Electric tool system

Abstract

To provide various electric tools and electric tool systems which are operable using various AC power sources and DC power sources.SOLUTION: An electric tool system (1) includes: a first electric tool (10A1) having a first electric tool rated voltage; second electric tools (10A2, 10A3 and 10B) having second electric tool rated voltages different from the first electric tool rated voltage; and a first battery pack (20A4) which can be coupled to the first electric tool (10A1) and the second electric tools (10A2, 10A3 and 10B). The first battery pack (20A4) is switchable between a first configuration having a first battery pack rated voltage corresponding to the first electric tool rated voltage so that the first battery pack can operate the first electric tool (10A1), and a second configuration having a convertible battery pack rated voltage corresponding to the second electric tool rated voltage (10A2) so that the battery pack can operate the second electric tools (10A2, 10A3 and 10B).SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to U.S. Provisional Patent Application No. 61 / 994,953, filed May 18, 2014, entitled "Power Tool System"; U.S. Provisional Patent Application No. 62 / 000,112, filed May 19, 2014, entitled "Power Tool System"; U.S. Provisional Patent Application No. 62 / 046,546, filed September 5, 2014, entitled "Convertible Battery Pack"; U.S. Provisional Patent Application No. 62 / 118,917, filed February 20, 2015, entitled "Convertible Battery Pack"; U.S. Provisional Patent Application No. 62 / 091,134, filed December 12, 2014, entitled "Convertible Battery Pack"; U.S. Provisional Patent Application No. 62 / 114,645, filed February 11, 2015, entitled "Transport for System for Convertible Battery Pack"; U.S. Provisional Patent Application No. 62 / 000,307, filed May 19, 2014, entitled "Cycle - By - Cycle Current Limit for Power Tools Having a Brushless Motor"; and U.S. Provisional Patent Application No. 62 / 093,513, filed December 18, 2014, entitled "Conduction Band Control for Brushless Motors in Power Tools", under 35 U.S.C. § 119(e), and each of these patent documents is incorporated herein by reference.

[0002] This application relates to a power tool system including various power tools and other electrical devices operable using various AC and DC power sources.

Background Art

[0003] Various types of power tools are generally used in construction, home renovation, outdoor, and do-it-yourself projects. Power tools generally fall into two categories: AC power tools (often also called corded power tools) that can operate using one or more AC power sources (such as AC commercial power or a generator), and DC power tools (often also called cordless power tools) that can operate using one or more DC power sources (such as a removable and rechargeable battery pack).

[0004] Corded or AC power tools are generally used in heavy-duty applications such as heavy-duty sawing, heavy-duty drilling and hammering, and heavy-duty metalworking that require higher power and / or longer operating times compared to the uses of cordless power tools. However, as the name implies, corded tools require the use of a cord that can be connected to an AC power source. In many applications, such as at a construction site, connecting to an AC power source is not practical and / or AC power has to be generated by a separate AC power generator, such as a generator powered by gasoline.

[0005] Cordless or DC power tools are generally used in lighter-duty applications such as light-duty sawing, light-duty drilling and fastening that require lower power and / or shorter operating times compared to the uses of corded power tools. Since cordless tools can be more limited in their power and / or run time, they are generally not industrially acceptable in many of the heavier-duty applications. Also, cordless tools are limited in weight because higher voltage and / or capacity batteries have a greater weight, which tends to create ergonomic drawbacks.

[0006] In addition, AC and DC power tools can operate using many different types of motors and motor control circuits. For example, corded or AC power tools can operate using an AC brushed motor, a universal brushed motor (operable using AC or DC), or a brushless motor. The motor in a corded tool can have a structure optimized or rated to operate by an AC voltage source having a rated voltage substantially the same as the AC commercial power supply (e.g., 120V in the United States and 230V in most of Europe). The motor in an AC or corded tool is generally controlled using an AC control circuit that can include an on-off switch (e.g., in the case of a tool operating at a substantially constant no-load speed) or a variable speed control circuit such as a triac control circuit (e.g., in the case of a motor tool operating at a variable no-load speed). An example of a triac control circuit can be found in Patent Document 1, which is incorporated herein by reference.

[0007] Also, cordless or DC power tools can operate using many different types of motors and control circuits. For example, cordless or DC power tools can operate using a DC brushed motor, a universal brushed motor, or a brushless motor. Since the batteries of cordless power tools tend to have a rated voltage lower than that of AC commercial power (e.g., 12V, 20V, 40V, etc.), the motors of cordless or DC power tools generally have a structure optimized or rated to be used with a DC power source having one or more of these lower voltages. The control circuit for a cordless or DC power tool can include an on-off switch (e.g., in the case of a tool operating at a substantially constant no-load speed) or a variable speed control circuit (e.g., in the case of a tool operating at a variable no-load speed). The variable speed control circuit may have, for example, an analog voltage regulator or a digital pulse-width modulation (PWM) control device to control the power supply to the motor. An example of a PWM control circuit can be found in Patent Document 2, which is incorporated by reference herein.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Means for Solving the Problems

[0009] In one aspect, the power tool system includes a first power tool having a low power tool rated voltage, a second power tool having an intermediate power tool rated voltage higher than the low power tool rated voltage, a third power tool having a high power tool rated voltage higher than the intermediate power tool rated voltage, a first battery pack having a low battery pack rated voltage corresponding to the low power tool rated voltage, and a convertible battery pack. The convertible battery pack is operable in a first configuration in which the convertible battery pack has a convertible battery pack rated voltage corresponding to the first power tool rated voltage and in a second configuration in which the convertible battery pack has a second convertible battery pack rated voltage corresponding to the second power tool rated voltage. The first battery pack is connectable to the first power tool to enable operation of the first power tool. The convertible battery pack is connectable to the first power tool in the first configuration to enable operation of the first power tool. The convertible battery pack is connectable to the second power tool in the second configuration to enable operation of the second power tool. A plurality of convertible battery packs are connectable to the third power tool in the second configuration to enable operation of the third power tool.

[0010] Embodiments of this aspect may include one or more of the following features. The third power tool may alternatively be connectable to an AC power source having a rated voltage corresponding to the voltage rating of the AC commercial power source to enable operation of the third power tool using a plurality of convertible battery packs or the AC power source. The AC commercial power source voltage rating may be about 100 volts to 120 volts or about 220 volts to 240 volts. The high power tool rated voltage may correspond to the voltage rating of the AC commercial power source. The system may further include a battery pack charger having a low charger rated voltage corresponding to the low battery pack rated voltage and to the convertible battery pack rated voltage, in which case the battery pack charger is configured to be coupled to the first battery pack to charge the first battery pack and to be coupled to the convertible battery pack to charge the convertible battery pack when in the first configuration.

[0011] The rated voltage of the intermediate power tool may be an integer multiple of the rated voltage of the low power tool, and the rated voltage of the high power tool may be an integer multiple of the rated voltage of the intermediate power tool. The rated voltage of the low power tool may be about 17 volts to 20 volts, the rated voltage of the intermediate power tool may be about 51 volts to 60 volts, and the rated voltage of the high power tool may be about 102 volts to 120 volts. The first power tool may have been sold before May 18, 2014, and the second and third power tools may not have been sold before May 18, 2014. The first power tool may be a DC-only power tool, the second power tool may be a DC-only power tool, and the third power tool may be an AC / DC power tool.

[0012] When the convertible battery pack is coupled to the first power tool, it may be automatically configured into a first configuration, and when coupled to the second or third power tool, it may be automatically configured into a second configuration. The system may include a third battery pack having an intermediate battery pack rated voltage. The third battery pack may be connectable to the second power tool to enable operation of the second power tool. A plurality of third battery packs may be connectable to the third power tool to enable operation of the third power tool. The first battery pack may not have the ability to enable operation of the second or third power tool.

[0013] In another aspect, the power tool system includes a first battery pack having a first battery pack rated voltage, a convertible battery pack that is operable in a first configuration in which the convertible battery pack has the first battery pack rated voltage and in a second configuration in which the convertible battery pack has a second convertible battery pack rated voltage that is higher than the first convertible battery pack rated voltage. The first power tool has a first motor, a first motor control circuit, and a first power interface. The first power tool has a first power tool rated voltage corresponding to the first battery pack rated voltage and a first convertible battery pack rated voltage. The first power tool is operable using the first battery pack when the first power interface is coupled to the first battery pack or using the convertible battery pack when the first power interface is coupled to the convertible battery pack such that the convertible battery pack is in the first configuration. The second power tool has a second motor, a second motor control circuit, and a second power interface. The second power tool has a second power tool rated voltage corresponding to the second convertible battery pack rated voltage. The second power tool is operable using the convertible battery pack when the second power interface is coupled to the convertible battery pack such that the convertible battery pack is in the second configuration. The third power tool has a third motor, a third motor control circuit, and a third power interface. The third power tool has a third rated voltage that is an integer multiple of the second convertible battery pack rated voltage. The third power tool is operable using a plurality of convertible battery packs when the third power tool interface is coupled to the plurality of convertible battery packs such that each of the plurality of convertible battery packs is in the second configuration.

[0014] Embodiments of this aspect may include one or more of the following features. The third power interface of the third power tool may alternatively be connectable to an AC power source having a rated voltage corresponding to the voltage rating of the AC commercial power source to enable operation of the third power tool using a plurality of convertible battery packs or the AC power source. The voltage rating of the AC commercial power source may be about 100 volts to 120 volts or about 220 volts to 240 volts. The high power tool rated voltage may correspond to the voltage rating of the AC commercial power source.

[0015] The system may include a battery pack charger having a first charger rated voltage corresponding to the first battery pack rated voltage and to the first convertible battery pack rated voltage. The battery pack charger may be configured to be coupled to the first battery pack to charge the first battery pack and, when in the first configuration, to be coupled to the convertible battery pack to charge the convertible battery pack. The second power tool rated voltage may be an integer multiple of the first power tool rated voltage. The first power tool rated voltage may be about 17 volts to 20 volts, the second power tool rated voltage may be about 51 volts to 60 volts, and the third power tool rated voltage may be about 100 volts to 120 volts. The first power tool may have been sold before May 18, 2014, and the second and third power tools may not have been sold before May 18, 2014.

[0016] The first power tool may be a DC-only power tool. The second power tool may be a DC-only power tool. The third power tool may be an AC / DC power tool. The convertible battery pack may be automatically configured in a first configuration when coupled to the first power tool and may be automatically configured in a second configuration when coupled to the second power tool or the third power tool. The system may include a third battery pack having a third battery pack rated voltage corresponding to the second power tool rated voltage. The third battery pack may be connectable to the second power tool to enable operation of the second power tool, and a plurality of third battery packs may be connectable to the third power tool to enable operation of the third power tool. The first battery pack may not have the ability to enable operation of the second power tool or the third power tool.

[0017] In another aspect, a power tool includes a power supply interface, a motor, and a motor control circuit. The power supply interface is configured to receive AC power from an AC power supply having a rated AC voltage corresponding to the rated voltage of the AC commercial power supply and to receive DC power from one or more removable battery packs having a total rated DC voltage corresponding to the rated voltage of the AC commercial power supply. The motor has a rated voltage corresponding to the rated AC voltage and to the rated DC voltage. The motor is operable using both AC power from the AC power supply and DC power from the DC power supply. The motor control circuit is configured to control operation of the motor using one of the AC power and the DC power without reducing the magnitude of the rated AC voltage, without reducing the magnitude of the rated DC voltage, and without converting the DC power to AC power.

[0018] Embodiments of this aspect may include one or more of the following features. The rated AC voltage may be about 100 volts to 120 volts. The DC rated voltage may be about 102 volts to about 120 volts. The rated voltage of the motor is about 100 volts to 120 volts. The rated AC voltage may include the RMS voltage of 120VAC, and the rated DC voltage may include the nominal voltage of 120 volts. The rated AC voltage may include an average voltage of about 108 volts, and the rated DC voltage may include a nominal voltage of about 108 volts. The AC power source may include an AC commercial power source.

[0019] One or more removable battery packs may include at least two removable battery packs. At least two battery packs may be connected in series with each other. Each battery pack may have a DC rated voltage that is approximately half of the rated AC voltage. The motor may be a universal motor. The control circuit may be configured to operate the universal motor at a constant no-load speed. The control circuit is configured to operate the universal motor at a variable no-load speed based on user input. The motor may include a brushless motor.

[0020] In another aspect, the power tool system includes a DC power source and a power tool. The DC power source includes one or more battery packs that cooperate to have a rated DC voltage corresponding to the rated voltage of the AC commercial power supply. The power tool has a power interface, a motor, and a motor control circuit. The power interface is configured to receive AC power from an AC power source having the rated voltage of the AC commercial power supply and to receive DC power from the DC power source. The motor has a rated voltage corresponding to the rated voltage of the AC commercial power supply and the rated DC voltage. The motor is operable using both AC power from the AC commercial power supply and DC power from the DC power source. The motor control circuit is configured to control the operation of the motor using one of the AC power and the DC power without reducing the magnitude of the rated AC voltage, without reducing the magnitude of the rated DC voltage, and without converting DC power to AC power.

[0021] Embodiments of this aspect may include one or more of the following features. The rated AC voltage may be about 100 volts to 120 volts. The DC rated voltage may be about 102 volts to about 120 volts. The rated voltage of the motor is about 100 volts to 120 volts. The rated AC voltage may include a 120VAC RMS voltage, and the rated DC voltage may include a nominal voltage of 120 volts. The rated AC voltage may include an average voltage of about 108 volts, and the rated DC voltage may include a nominal voltage of about 108 volts. The AC power source may include an AC commercial power supply.

[0022] One or more removable battery packs may include at least two removable battery packs. The at least two battery packs may be connected in series with each other. Each battery pack may have a rated DC voltage that is about half of the rated AC voltage. The motor may be a universal motor. The control circuit may be configured to operate the universal motor at a constant no-load speed. The control circuit is configured to operate the universal motor at a variable no-load speed based on user input. The motor may include a brushless motor.

[0023] In another aspect, the power tool includes a power interface, a motor, and a motor control circuit. The power interface is configured to receive AC power from an AC commercial power source having a rated AC voltage and to receive DC power from a DC power source having one or more battery packs that cooperate to have a rated DC voltage different from the rated AC voltage. The motor has a rated voltage corresponding to one of the rated AC voltage and the rated DC voltage. The motor is operable using both AC power from the AC power source and DC power from the DC power source. The motor control circuit is configured to enable operation of the motor using one of the AC power and the DC power such that the motor has substantially the same output speed performance when operating using the AC power source and the DC power source.

[0024] Embodiments of this aspect may include one or more of the following features. The rated DC voltage may be less than the rated AC voltage. The rated AC voltage may be about 100 volts to 120 volts, and the rated DC voltage may be less than 100 volts. The rated DC voltage may be about 51 volts to 60 volts. The rated AC voltage may be less than the rated DC voltage. The one or more battery packs may include two battery packs connected to each other in series, in which case each battery pack has a rated voltage that is about half of the rated AC voltage. The motor may be a universal motor. The control circuit may operate the universal motor at a constant no-load speed. The control circuit may operate the universal motor at a variable no-load speed based on user input. When operating using an AC power source and a DC power source, the control circuit may optimize the pulse width modulation range according to the rated voltages of the AC power source and the DC power source so that the motor has substantially the same output performance. The motor may be a brushless motor. When operating using an AC power source and a DC power source, the control circuit may use at least one of per-cycle current limiting, conduction band control, and advance angle control so that the motor has substantially the same output speed performance.

[0025] In another aspect, the power tool includes means for receiving AC power from an AC commercial power source having a rated AC voltage, and means for receiving DC power from a DC power source having one or more battery packs having a rated DC voltage different from the rated AC voltage. Further, the power tool has a motor having a rated voltage corresponding to the higher of the rated AC voltage and the rated DC voltage. The motor is operable using both AC power from the AC power source and DC power from the DC power source. Also, when operating using the AC power source and the DC power source, the power tool has means for operating the motor using one of the AC power and the DC power so that the motor has substantially the same output speed performance.

[0026] Embodiments of this aspect may include one or more of the following features. The rated DC voltage may be less than the rated AC voltage. The rated AC voltage may be about 100 volts to 120 volts, and the DC voltage may be less than 100 volts. The rated DC voltage may be about 51 volts to 60 volts. The rated AC voltage may be less than the rated DC voltage. The one or more battery packs may include two battery packs connected to each other in series, in which case each battery pack has a rated voltage that is about half of the rated AC voltage. The motor may be a universal motor. The means for operating the motor may operate the universal motor at a constant no-load speed. The means for operating the motor may operate the universal motor at a variable no-load speed based on user input. The means for operating the motor may optimize the pulse width modulation range according to the rated voltages of the AC power supply and the DC power supply so that the motor has substantially the same output speed performance when operating using the AC power supply and the DC power supply. The motor may be a brushless motor. The means for operating the motor may use at least one of per-cycle current limiting, conduction band control, and advance angle control so that the motor has substantially the same output speed performance when operating using the AC power supply and the DC power supply.

[0027] In another aspect, the power tool system includes a first power tool having a first power tool rated voltage, a second power tool having a second power tool rated voltage different from the first power tool rated voltage, and a first battery pack connectable to the first power tool and the second power tool. The first battery pack is switchable between a first configuration having a first battery pack rated voltage corresponding to the first power tool rated voltage such that the first battery pack enables operation of the first power tool and a second configuration having a convertible battery pack rated voltage corresponding to the second power tool rated voltage such that the battery pack enables operation of the second power tool.

[0028] Embodiments of this aspect may include one or more of the following features. The system may include a second removable battery pack having a first battery pack rated voltage and configured to be coupled to a first power tool to enable operation of the first power tool, but not to enable operation of a second power tool. The second power tool rated voltage may be greater than the first power tool rated voltage. The first power tool rated voltage may be an integer multiple of the second power tool rated voltage. The first power tool rated voltage may be about 17 volts to 20 volts, and the second power tool rated voltage may be about 51 volts to 60 volts. The first power tool may have been sold prior to May 18, 2014, and the second power tool may not have been sold prior to May 18, 2014. The first power tool may be a DC-only power tool, and the second power tool may be a DC-only power tool or an AC / DC power tool. Alternatively, the second power tool may be connectable to an AC power source having a rated voltage corresponding to the voltage rating of an AC commercial power source to enable operation of the second power tool using an interchangeable battery pack or the AC power source.

[0029] According to another aspect of the present invention, there is provided a power tool, the power tool comprising: a housing; an electric universal motor having a positive terminal, a negative terminal, and a commutator engaged with a pair of brushes coupled to the positive and negative terminals, the motor being configured to operate within an operating voltage range of about 90V to 132V; a power interface configured to receive at least one of AC power from an AC power source having a first nominal voltage and DC power from a DC power source having a second nominal voltage, the DC power source having at least one removable battery pack coupled to the power interface, the power interface being configured to output AC power via an AC power line and output DC power via a DC power line, the first and second nominal voltages being substantially within the operating voltage range of the motor; and a motor control circuit configured to supply power from one of the AC power line or the DC power line to the motor via a common node such that the brush is electrically coupled to one of the AC or DC power sources.

[0030] In one embodiment, the motor control circuit has an on / off switch disposed between the common node of the AC and DC power lines and the motor.

[0031] In one embodiment, the motor control circuit has a control unit coupled to a power switch disposed on the DC power line. In one embodiment, the control unit is configured to monitor a fault condition associated with the DC power source and turn off the power switch to interrupt the supply of power from the DC power source to the motor.

[0032] In one embodiment, the power tool further includes a power switching unit configured to isolate the AC power line and the DC power line. In one embodiment, the power switching unit has a relay switch disposed on the DC power line and activated by a coil coupled to the AC power line. In one embodiment, the power switching unit has at least one double-pole double-throw switch disposed between the common node of the AC and DC power lines and the power interface. In one embodiment, the power switching unit has at least one single-pole double-throw switch having an output terminal coupled to the common node of the AC and DC power lines.

[0033] In one embodiment, the DC power source has a high-rated voltage battery pack.

[0034] In one embodiment, the DC power source includes at least two medium-rated voltage battery packs, and the power interface is configured to connect two or more of the at least two battery packs in series.

[0035] According to another aspect of the present invention, the power tool described above is a variable speed tool as described herein.

[0036] In one embodiment, the power tool further includes a DC switch circuit disposed between the DC power line and the motor, an AC switch disposed between the AC power line and the motor, and a control unit configured to control the switching operation of the DC switch circuit or the AC switch to enable variable speed operation of the motor at a constant torque by controlling the speed of the motor.

[0037] In one embodiment, the DC switch circuit comprises one or more controllable semiconductor switches configured as at least one of a chopper circuit, a half-bridge circuit, or a full-bridge circuit, and the control unit is configured to control the pulse-width modulation (PWM) duty cycle of the one or more semiconductor switches according to a desired motor speed.

[0038] In one embodiment, the AC switch comprises a phase-controlled switch having at least one of a triac, a thyristor, or an SCR switch, and the control unit is configured to control the phase of the AC switch according to a desired motor speed.

[0039] In one embodiment, the control unit is configured to detect a current on one of the AC power line or the DC power line to set the operating mode to one of the AC operating mode or the DC operating mode, and to control the switching operation of either the DC switch circuit or the AC switch based on the operating mode.

[0040] In an alternative embodiment, the power tool further comprises a power switching unit having a diode bridge and a controllable semiconductor switch incorporated within the diode bridge, wherein the AC and DC power lines of the power interface are coupled together to a first node of the diode bridge, and the motor is coupled to a second node of the diode bridge, and a control unit configured to control the switching operation of the semiconductor switch to enable variable speed operation of the motor at a constant torque by controlling the speed of the motor.

[0041] In one embodiment, the control unit is configured to detect a current on one of the AC power line or the DC power line so as to set the operation mode to one of the AC operation mode or the DC operation mode, and to control the switching operation of the semiconductor switch according to the operation mode.

[0042] In one embodiment, in the DC operation mode, the control unit is configured to set a pulse width modulation (PWM) duty cycle according to a desired motor speed, and to periodically turn on and off the semiconductor switch according to the PWM duty cycle.

[0043] In one embodiment, in the AC operation mode, the control unit is configured to set a conduction band according to a desired motor speed, and to turn on the semiconductor switch at approximately the start point of the conduction band and turn off the semiconductor switch at approximately the zero crossing of the AC power line within a half cycle of each AC line.

[0044] In one embodiment, the power tool further includes a second semiconductor switch and a freewheel diode arranged in series between the power tool and the motor to allow a current path for the motor current during the off cycle of the semiconductor switch in the DC operation mode.

[0045] In one embodiment, the semiconductor switch includes one of a field effect transistor (FET) and an insulated gate bipolar transistor (IGBT).

[0046] In one embodiment, the diode bridge is configured to rectify the AC power line through the semiconductor switch rather than through the motor.

[0047] In one embodiment, the semiconductor switching unit is disposed between the common nodes of the AC and DC power lines.

[0048] According to another aspect of the present invention, there is provided a power tool, the power tool including: a housing; a universal motor having a positive terminal, a negative terminal, and a commutator engaged with a pair of brushes coupled to the positive and negative terminals, the motor being configured to operate within an operating voltage range; a power interface configured to receive at least one of AC power from an AC power source having a first nominal voltage or DC power from a DC power source having a second nominal voltage, the DC power source having at least one removable battery pack coupled to the power interface, the power interface being configured to output AC power via an AC power line and output DC power via a DC power line, the second nominal voltage being substantially within the operating voltage range of the motor, but the first nominal voltage being substantially higher than the operating voltage range of the motor; and a motor control circuit configured to supply power from one of the AC power line or the DC power line to the motor via a common node such that the brushes are electrically coupled to one of the AC or DC power sources, the motor control circuit being configured to reduce the supply of power from the AC power line to the motor to a level corresponding to the operating voltage of the operating voltage range of the motor.

[0049] In one embodiment, the motor control circuit includes an AC switch disposed in series with the AC power line, and a control unit configured to control the phase of the AC power line via the AC switch and set a fixed conduction band of the AC switch to reduce the average voltage value on the AC line to a level corresponding to the operating voltage range of the motor.

[0050] In one embodiment, the motor control circuit has an on / off switch disposed between the common node of the AC and DC power lines and the motor.

[0051] In one embodiment, the motor control circuit has a control unit coupled to a power switch disposed on the DC power line. In one embodiment, the control unit is configured to monitor a fault condition associated with the DC power supply and to turn off the power switch to interrupt the supply of power from the DC power supply to the motor.

[0052] In one embodiment, the power tool further has a power switching unit configured to isolate the AC power line and the DC power line. In one embodiment, the power switching unit has a relay switch disposed on the DC power line and activated by a coil coupled to the AC power line. In one embodiment, the power switching unit has at least one double-pole double-throw switch disposed between a common node of the AC and DC power lines and the power interface. In one embodiment, the power switching unit has at least one single-pole double-throw switch having an output terminal coupled to the common node of the AC and DC power lines.

[0053] In one embodiment, the DC power supply has a high-rated voltage battery pack.

[0054] In one embodiment, the DC power supply comprises at least two intermediate-rated voltage battery packs, and the power interface is configured to connect two or more of the at least two battery packs in series. In one embodiment, the operating voltage range of the motor is within a range of about 100V to 120V including a second nominal voltage, and the first nominal voltage is within a range of 220VAC to 240VAC. In one embodiment, the control unit is configured to set a fixed conduction band of the AC switch to a value within a range of 100 to 140 degrees.

[0055] In one embodiment, the operating voltage range of the motor is within a range of approximately 60V to 90V that includes the second nominal voltage, and the first nominal voltage is within a range of 100VAC to 120VAC. In one embodiment, the control unit is configured to set the fixed conduction band of the AC switch to a value within a range of 70 to 110 degrees.

[0056] In one embodiment, the control unit is configured to operate the tool at a constant speed in the fixed conduction band.

[0057] In one embodiment, the AC switch includes a phase-controlled switch having one of a triac, a silicon controlled rectifier, or an SCR switch, and the controller is configured to control the phase of the AC switch according to the desired motor speed.

[0058] According to another aspect of the present invention, the electric power tool described above is a variable speed electric power tool as described herein.

[0059] According to one embodiment, the motor control circuit further includes a DC switch circuit disposed between the DC power line and the motor, and in this case, the control unit is configured to control the switching operation of the DC switch circuit or the AC switch to enable variable speed operation of the motor at a constant load by controlling the speed of the motor.

[0060] According to one embodiment, the DC switch circuit includes one or more controllable semiconductor switches configured as at least one of a chopper circuit, a half-bridge circuit, or a full-bridge circuit, and the control unit is configured to control the pulse width modulation (PWM) duty cycle of the one or more semiconductor switches according to the desired motor speed.

[0061] According to one embodiment, the control unit is configured to change the conduction angle of the AC switch from zero to a fixed conduction band up to the maximum according to the desired motor speed.

[0062] According to one embodiment, the control unit is configured to detect the current on one of the AC power line or the DC power line to set the operation mode to one of the AC operation mode or the DC operation mode, and to control the switching operation of one or the other of the DC switch circuit or the AC switch based on the operation mode.

[0063] According to one embodiment, the motor control circuit is a power switching unit including a diode bridge and a controllable semiconductor switch incorporated in the diode bridge, wherein the AC and DC power lines of the power interface are coupled together to a first node of the diode bridge, and the motor is coupled to a second node of the diode bridge, and a control unit configured to control the switching operation of the semiconductor switch to enable variable speed operation of the motor at a constant load by controlling the speed of the motor, and a control unit configured to control the phase of the AC power line via the semiconductor switch.

[0064] In one embodiment, the control unit is configured to detect the current on one of the AC power line or the DC power line to set the operation mode to one of the AC operation mode or the DC operation mode, and to control the switching operation of the semiconductor switch in one of the AC operation mode or the DC operation mode according to the operation mode.

[0065] In one embodiment, in the DC operation mode, the control unit is configured to set a pulse width modulation (PWM) duty cycle according to the desired motor speed, and to periodically activate and deactivate the semiconductor switch according to the PWM duty cycle.

[0066] In one embodiment, in the AC operation mode, the control unit is configured to set a maximum conduction band corresponding to the operating voltage range of the motor.

[0067] In one embodiment, the control unit is configured to set the conduction band from zero to maximum up to the maximum conduction band according to and proportional to the desired motor speed, and within each AC line half-cycle, turn on the semiconductor switch at approximately the start point of the conduction band and turn off the semiconductor switch at approximately the zero crossing of the AC power line.

[0068] In one embodiment, the operating voltage range of the motor is approximately in the range of 100V to 120V including the second nominal voltage, and the first nominal voltage is in the range of 220VAC to 240VAC. In one embodiment, the control unit is configured to set the maximum conduction band to a value within the range of 100 to 140 degrees.

[0069] In one embodiment, the operating voltage range of the motor is approximately in the range of 60V to 100V including the second nominal voltage, and the first nominal voltage is in the range of 100VAC to 120VAC. In one embodiment, the control unit is configured to set the maximum conduction band of the AC switch to a value within the range of 70 to 110 degrees.

[0070] In one embodiment, the diode bridge is configured to rectify the AC power line through the semiconductor switch without passing through the motor.

[0071] In one embodiment, the motor control circuit further includes a second semiconductor switch and a freewheel diode arranged in series with the motor to allow a current path for the motor current in the off-cycle of the semiconductor switch in the DC operation mode.

[0072] In one embodiment, the semiconductor switch has one of a field effect transistor (FET) or an insulated gate bipolar transistor (IGBT).

[0073] According to another aspect of the present invention, there is provided a power tool, the power tool comprising: a housing; an electric universal motor having a positive terminal, a negative terminal, and a commutator engaged with a pair of brushes coupled to the positive and negative terminals; a power interface configured to receive at least one of AC power from an AC power source or DC power from a DC power source, and to output AC power via an AC power line and DC power via a DC power line; a power switching unit having a diode bridge and a controllable semiconductor switch incorporated in the diode bridge, wherein the AC and DC power lines of the power interface are commonly coupled to a first node of the diode bridge, and the motor is coupled to a second node of the diode bridge; and a control unit configured to control the switching operation of the semiconductor switch so as to enable variable speed operation of the motor at a constant torque by controlling the speed of the motor.

[0074] In one embodiment, the control unit is configured to detect a current on one of the AC power line or the DC power line to set an operation mode to one of an AC operation mode or a DC operation mode, and to control the switching operation of the semiconductor switch according to the operation mode.

[0075] In one embodiment, in the DC operation mode, the control unit is configured to set a pulse width modulation (PWM) duty cycle according to a desired motor speed, and to periodically activate and deactivate the semiconductor switch according to the PWM duty cycle.

[0076] In one embodiment, in the AC operation mode, the control unit sets the conduction band according to the desired speed of the motor, and in each AC line half-cycle, is configured to turn on the semiconductor switch at approximately the starting point of the conduction band and turn off the semiconductor switch at approximately the zero crossing of the AC power line.

[0077] In one embodiment, the power tool further has a second semiconductor switch and a freewheel diode arranged in series with the motor to allow a current path for the motor current in the off-cycle of the semiconductor switch in the DC operation mode.

[0078] In one embodiment, the semiconductor switch has one of a field effect transistor (FET) or an insulated gate bipolar transistor (IGBT).

[0079] In one embodiment, the diode bridge is configured to rectify the AC power line through the semiconductor switch without passing through the motor.

[0080] In one embodiment, the power switching unit is arranged between the common nodes of the AC and DC power lines.

[0081] According to another aspect of the present invention, a power tool is provided, the power tool comprising a housing and an electric direct current (DC) motor having a positive terminal, a negative terminal, and a commutator engaged with a pair of brushes coupled to the positive and negative terminals, the motor being configured to operate within an operating voltage range of approximately 90V to 132V, and a power interface configured to receive at least one of AC power from an AC power source having a first nominal voltage or DC power from a DC power source having a second nominal voltage, the DC power source having at least one removable battery pack coupled to the power interface, the power interface being configured to output AC power via an AC power line and output DC power via a DC power line, the first and second nominal voltages being included within approximately the operating voltage range of the motor, and a motor control circuit including a rectifier circuit configured to rectify an alternating current signal into a rectified signal on the AC power line, the motor control circuit being configured to supply power from one of the AC line or the DC line to the motor via a common node such that the brushes are electrically coupled to one of the AC or DC power sources.

[0082] In one embodiment, the rectifier circuit includes a full-wave diode bridge rectifier.

[0083] In one embodiment, the motor control circuit has an on / off switch disposed between the common node of the AC and DC power lines and the motor.

[0084] In one embodiment, the motor control circuit has a control unit coupled to a power switch disposed on the DC power line. In one embodiment, the control unit is configured to monitor a fault condition associated with the DC power source and turn off the power switch to interrupt the supply of power from the DC power source to the motor.

[0085] In one embodiment, the power tool further includes a power switching unit configured to isolate the AC power line and the DC power line. In one embodiment, the power switching unit has a relay switch disposed on the DC power line and activated by a coil coupled to the AC power line. In one embodiment, the power switching unit has at least one double-pole double-throw switch disposed between the common node of the AC and DC power lines and the power interface. In one embodiment, the power switching unit includes at least one single-pole double-throw switch having an output terminal coupled to the common node of the AC and DC power lines.

[0086] In one embodiment, the DC power source has a high-rated voltage battery pack.

[0087] In one embodiment, the DC power source includes at least two medium-rated voltage battery packs, and the power interface is configured to connect two or more of the at least two battery packs in series.

[0088] According to another aspect of the present invention, the power tool described above is a variable-speed tool as described herein.

[0089] In one embodiment, the power tool further includes a switching circuit disposed between the common node of the AC and DC power lines and the motor, and a control unit configured to control the switching operation of the switching circuit to enable variable-speed operation of the motor at a constant torque by controlling the speed of the motor.

[0090] In one embodiment, the switching circuit comprises one or more controllable semiconductor switches configured as at least one of a chopper circuit, a half-bridge circuit, or a full-bridge circuit, and the control unit is configured to control the pulse-width modulation (PWM) duty cycle of the one or more semiconductor switches according to a desired motor speed.

[0091] In one embodiment, the motor is a permanent magnet DC motor.

[0092] According to another aspect of the present invention, a power tool is provided, the power tool comprising a housing, an electrical direct current (DC) motor having a positive terminal, a negative terminal, and a commutator engaged with a pair of brushes coupled to the positive and negative terminals, the motor being configured to operate within an operating voltage range, a power interface configured to receive at least one of AC power from an AC power source having a first nominal voltage or DC power from a DC power source having a second nominal voltage, the DC power source having at least one removable battery pack coupled to the power interface, the power interface being configured to output AC power via an AC power line and DC power via a DC power line, the second nominal voltage being substantially within the operating voltage range of the motor, but the first nominal voltage being substantially higher than the operating voltage range of the motor, a motor control circuit including a rectifier circuit configured to rectify an alternating current signal into a rectified signal on the AC power line, the motor control circuit being configured to supply power from one of the AC power line or the DC power line to the motor via a common node such that the brushes are electrically coupled to one of the AC or DC power sources, and the motor control circuit being configured to reduce the supply of power from the AC power line to the motor to a level corresponding to the operating voltage range of the motor.

[0093] In one embodiment, the rectifier circuit includes a half-wave diode bridge circuit configured to reduce the average voltage value on the AC power line by about half.

[0094] In one embodiment, the motor control circuit includes a power switch disposed between the common nodes of the AC and DC power lines, and a control unit configured to control the pulse width modulation (PWM) of the power switch. The control unit is configured to set the pulse width modulation (PWM) duty cycle of the power switch to a fixed value less than 100% so as to reduce the average voltage value on the AC line to a level corresponding to the operating voltage range of the motor. In one embodiment, the power switch has one of a field effect transistor (FET) or an insulated gate bipolar transistor (IGBT).

[0095] In one embodiment, the motor control circuit includes an AC switch disposed in series with the AC power line between the power interface and the rectifier circuit, and a control unit configured to control the phase of the AC power line via the AC switch and set a fixed conduction band of the AC switch so as to reduce the average voltage value on the AC power line to a level corresponding to the operating voltage range of the motor.

[0096] In one embodiment, the AC switch includes a phase-controlled switch having one of a triac, a thyristor, or an SCR switch, and the controller is configured to control the phase of the AC switch according to the desired motor speed.

[0097] In one embodiment, the motor control circuit has an on / off switch disposed between the common node of the AC and DC power lines and the motor.

[0098] In one embodiment, the motor control circuit has a control unit coupled to a power switch disposed on the DC power line. In one embodiment, the control unit is configured to monitor a fault condition associated with the DC power supply and turn off the power switch to interrupt the power supply from the DC power supply to the motor.

[0099] In one embodiment, the power tool further includes a power switching unit configured to isolate the AC power line and the DC power line. In one embodiment, the power switching unit has a relay switch disposed on the DC power line and activated by a coil coupled to the AC power line. In one embodiment, the power switching unit has at least one double-pole double-throw switch disposed between the common node of the AC and DC power lines and the power interface. In one embodiment, the power switching unit has at least one single-pole double-throw switch having an output terminal coupled to the common node of the AC and DC power lines.

[0100] In one embodiment, the DC power source has a high-rated voltage battery pack.

[0101] In one embodiment, the DC power source includes at least two medium-rated voltage battery packs, and the power interface is configured to connect two or more of the at least two battery packs in series. In another embodiment, the operating voltage range of the motor is approximately in the range of 100V to 120V including the second nominal voltage, and the first nominal voltage is in the range of 220VAC to 240VAC. In one embodiment, the control unit is configured to set the fixed conduction band of the AC switch to a value within the range of 100 to 140 degrees.

[0102] In one embodiment, the operating voltage range of the motor is approximately in the range of 60V to 90V including the second nominal voltage, and the first nominal voltage is in the range of 100VAC to 120VAC. In one embodiment, the control unit is configured to set the fixed conduction band of the AC switch to a value within the range of 70 to 110 degrees.

[0103] In one embodiment, the control unit is configured to operate the tool at a constant speed in the fixed conduction band.

[0104] According to another aspect of the present invention, the power tool described above is a variable speed tool, as described herein.

[0105] In one embodiment, the power tool further includes a switching circuit disposed between a common node of AC and DC power lines and the motor, and a control unit configured to control the pulse width modulation (PWM) switching operation of the switching circuit so as to enable variable speed operation of the motor at a constant torque by controlling the speed of the motor.

[0106] In one embodiment, the switching circuit includes one or more controllable semiconductor switches configured as at least one of a chopper circuit, a half-bridge circuit, or a full-bridge circuit, and the control unit is configured to control the pulse width modulation (PWM) duty cycle of the one or more semiconductor switches according to a desired motor speed.

[0107] According to one embodiment, the control unit is configured to detect a current on one of the AC power line or the DC power line so as to set the operation mode to one of an AC operation mode or a DC operation mode.

[0108] In one embodiment, the controller is configured to reduce the supply of power through the switching circuit to a level corresponding to the operating voltage range of the motor in the AC operation mode.

[0109] In one embodiment, the control unit is configured to control the switching operation of the switching circuit within a first duty cycle range in the DC operation mode and within a second duty cycle range in the AC operation mode, where the second duty cycle range is smaller than the first duty cycle range.

[0110] In one embodiment, the control unit is configured to control the switching operation of the switching circuit at a duty cycle from zero to 100% in the DC operation mode and to control the switching operation of the switching circuit up to a threshold less than 100% from zero in the AC operation mode.

[0111] According to another aspect of the present invention, a power tool is provided, the power tool comprising: a housing; a brushless direct current (BLDC) motor including a stator having at least three stator windings corresponding to at least three phases of a rotor and a motor, wherein the rotor is movable by the stator when appropriately energized within the phase corresponding to the stator winding, each phase being characterized by a corresponding voltage waveform for supplying energy to the corresponding stator winding, the motor being configured to operate within an operating voltage range; a power interface configured to receive at least one of AC power from an AC power source having a first nominal voltage or DC power from a DC power source having a second nominal voltage, the DC power source having at least one removable battery pack coupled to the power interface, the power interface being configured to output AC power via an AC power line and DC power via a DC power line; and a motor control circuit configured to receive the AC power line and the DC power line and to supply power to the motor at a level corresponding to the operating voltage range of the motor, the motor control circuit having a rectifier circuit configured to rectify an alternating signal on the AC power line into a rectified voltage signal on a DC bus line and a power switch circuit configured to regulate the supply of power from the DC bus line to the motor.

[0112] In one embodiment, the rectifier circuit has a diode bridge. In one embodiment, the rectifier circuit further has a link capacitor arranged in parallel with the diode bridge on the DC bus line. In one embodiment, the diode bridge has a full-wave bridge. In an alternative embodiment, the diode bridge has a half-wave bridge.

[0113] In one embodiment, the DC power line is directly connected to a node on the DC bus line, thereby bypassing the rectifier circuit. In an alternative embodiment, the DC power line and the AC power line are coupled together to the input node of the rectifier circuit.

[0114] In one embodiment, the power tool further has a power switching unit configured to isolate the AC power line and the DC power line. In one embodiment, the switching unit has a relay switch arranged on the DC power line and activated by a coil coupled to the AC power line. In one embodiment, the power switching unit has at least one single-pole double-throw switch having an input terminal coupled to the AC and DC power lines and an output terminal coupled to the input node of the rectifier circuit. In one embodiment, the power switching unit has at least one double-pole double-throw switch having an input terminal coupled to the AC and DC power lines, a first output terminal coupled to the input node of the rectifier circuit, and a second output terminal directly coupled to a node on the DC bus line, thereby bypassing the rectifier circuit.

[0115] In one embodiment, the motor control circuit further includes a controller configured to control the switching operation of the power switch circuit. In one embodiment, the controller is a programmable device including a microcontroller, a microprocessor, a computer processor, a signal processor. Alternatively, the controller is an integrated circuit configured and customized to control the switching operation of the power switch unit. In one embodiment, the control unit is further configured to monitor a fault condition associated with the power tool or the DC power supply and activate and deactivate the power switch circuit to interrupt the power supply to the motor. In one embodiment, the control unit is configured to detect a current on one of the AC power line or the DC power line to set the operating mode to one of the AC operating mode or the DC operating mode, and to control the switching operation of the power switch circuit based on the operating mode. In an alternative embodiment, the control unit is configured to control the switching operation of the power switch circuit regardless of the AC or DC operating mode.

[0116] In one embodiment, the power switch circuit has a plurality of power switches including three pairs of high-side and low-side power switches configured as a three-phase bridge circuit coupled to the phases of the motor.

[0117] In one embodiment, the motor control circuit further includes a gate driver circuit coupled to the controller and the power switch circuit and configured to drive the gates of the plurality of power switches based on one or more drive signals from the controller.

[0118] In one embodiment, the motor control circuit further includes a power supply regulator including at least one voltage regulator configured to output a voltage signal to supply power to at least one of the gate driver circuit or the controller.

[0119] In one embodiment, the motor control circuit is coupled to at least one of an on / off actuator or a trigger switch, and further includes an on / off switch configured to interrupt the supply of power from the power regulator and the gate driver circuit.

[0120] In one embodiment, the power tool further includes a plurality of position sensors disposed in the vicinity of the rotor to provide a rotational position signal of the rotor to the control unit. In one embodiment, the controller is configured to control the switching operation of the power switch circuit based on the position signal so as to appropriately supply energy to the stator winding at a corresponding phase.

[0121] According to one embodiment, at each phase of the motor, the controller is configured to activate a drive signal for a corresponding one of the plurality of power switches within a conduction band corresponding to the phase of the motor.

[0122] In one embodiment, the controller sets a pulse width modulation (PWM) duty cycle according to a desired motor speed, and controls the drive signal to periodically turn on and off a corresponding one of the plurality of power switches within the conduction band according to the PWM duty cycle to enable variable speed operation of the motor at a constant load.

[0123] According to one aspect of the present invention, both the first and second nominal voltages are substantially included within the operating voltage range of the motor.

[0124] In one embodiment, the operating voltage range of the motor is approximately within the range of 90V to 132V, which substantially includes the second nominal voltage, and the first nominal voltage is approximately within the range of 100VAC to 120VAC. In one embodiment, the DC power supply has a high-rated voltage battery pack. In one embodiment, the DC power supply includes at least two intermediate-rated voltage battery packs, and the power supply interface is configured to connect two or more of the at least two battery packs in series.

[0125] In one embodiment, the link capacitor has a capacitance value optimized to provide an average voltage of approximately 110V or less on the DC bus line when the power tool is powered by an AC power supply. In this case, the first nominal voltage is approximately 120VAC. In one embodiment, the link capacitor has a capacitance value of approximately 50 μF or less.

[0126] In one embodiment, the link capacitor has a capacitance value optimized to provide an average voltage of approximately 120V on the DC bus line when the power tool is powered by an AC power supply. In this case, the first nominal voltage is approximately 120VAC. In one embodiment, the link capacitor has a capacitance value of approximately 200 to 600 μF or less. In one embodiment, the DC power supply has a nominal voltage of approximately 120VDC.

[0127] According to one aspect of the present invention, at least one of the first and second nominal voltages does not substantially correspond to the operating voltage range of the motor.

[0128] In one embodiment, the motor control circuit is configured to optimize the supply of power from at least one of the AC power line or the DC power line to the motor at a level corresponding to the operating voltage range of the motor.

[0129] In one embodiment, the controller is configured to set the operating mode to one of an AC operating mode or a DC operating mode, and to control the switching operation of the power switch circuit based on the operating mode. In one embodiment, the controller is configured to detect the current on one of the AC power line or the DC power line in order to set the operating mode. In one embodiment, the controller is configured to receive a signal indicating the operating mode from the power interface.

[0130] In one embodiment, the operating voltage range of the motor includes the first nominal voltage but does not include the second nominal voltage. In one embodiment, the operating voltage range of the motor is approximately within the range of 100V to 120V including the first nominal voltage, and the second nominal voltage is within the range of about 60VDC to 100VDC. In one embodiment, the controller may be configured to increase the effective power supply to the motor in the DC operating mode so as to correspond to the operating voltage range of the motor.

[0131] In one embodiment, the operating voltage range of the motor includes the second nominal voltage but does not include the first nominal voltage. In one embodiment, the operating voltage range of the motor is approximately within the range of 60V to 100V including the second nominal voltage, and the first nominal voltage is within the range of about 100VAC to 120VAC. In one embodiment, the controller may be configured to reduce the effective power supply to the motor in the AC operating mode so as to correspond to the operating voltage range of the motor.

[0132] In one embodiment, the operating voltage range of the motor includes neither the first nominal voltage nor the second nominal voltage. In one embodiment, the motor control circuit is configured to optimize the supply of power to the motor from both the AC power line and the DC power line at a level corresponding to the operating voltage range of the motor.

[0133] In one embodiment, the operating voltage range of the motor is approximately in the range of 150V to 170V, the first nominal voltage is in the range of approximately 100VAC to 120VAC, and the second nominal voltage is in the range of approximately 90VDC to 120VDC. In one embodiment, the controller may be configured to increase the effective power supply to the motor in both the AC operating mode and the DC operating mode so as to correspond to the operating voltage range of the motor.

[0134] In one embodiment, the operating voltage range of the motor is approximately in the range of 150V to 170V, the first nominal voltage is approximately in the range of 220VAC to 240VAC, and the second nominal voltage is approximately in the range of 90VDC to 120VDC. In one embodiment, the controller may be configured to increase the effective power supply to the motor in the DC operating mode but reduce the effective power supply to the motor in the AC operating mode so as to correspond to the operating voltage of the motor.

[0135] In one embodiment, the controller is configured to control the switching operation of the power switch circuit via one or more drive signals at a fixed pulse width modulation (PWM) duty cycle, and the controller sets the fixed PWM duty cycle to a first value with respect to the first nominal voltage when powered by an AC power supply and to a second value different from the first value with respect to the second nominal voltage when powered by a DC power supply.

[0136] In one embodiment, the controller is configured to control the switching operation of the power switch circuit via one or more drive signals at a fixed pulse width modulation (PWM) duty cycle less than 100% in the AC operating mode so as to reduce the effective power supply to the motor in the AC operating mode corresponding to the operating voltage range of the motor.

[0137] In one embodiment, the controller is configured to control the switching operation of the power switch circuit via one or more drive signals at a pulse width modulation (PWM) duty cycle that is a maximum threshold value, and the controller sets the threshold value to a first value with respect to a first nominal voltage when powered by an AC power supply and to a second value different from the first value with respect to a second nominal voltage when powered by a DC power supply.

[0138] In one embodiment, the controller is configured to control the switching operation of the power switch circuit within a first duty cycle range in the DC operation mode and within a second duty cycle range in the AC operation mode so as to reduce the effective power supply to the motor in the AC operation mode corresponding to the operating voltage range of the motor, where the second PWM duty cycle range is smaller than the first duty cycle range.

[0139] In one embodiment, the controller is configured to control the switching operation of the power switch circuit at a duty cycle from zero to 100% in the DC operation mode and at a threshold value from zero to less than 100% in the AC operation mode so as to reduce the effective power supply to the motor in the AC operation mode corresponding to the operating voltage range of the motor.

[0140] In one embodiment, the controller is configured to receive a measured value of the instantaneous current on the DC bus line, and by comparing the instantaneous current measured value with a current limit, and in response to the instantaneous current measured value exceeding the current limit, turn off a plurality of power switches for the remaining portion of the current time interval to interrupt the current flowing through the electric motor, so as to implement current limiting for the current through the power switch circuit. In this case, the duration of each time interval is defined as a function of a given frequency at which the electric motor is controlled by the controller.

[0141] In one embodiment, the controller turns on the selected power switch at the end point of the current time interval, thereby resuming the flow of current to the motor.

[0142] In one embodiment, the duration of each time interval is about 10 times the "reciprocal of a given frequency at which the motor is controlled by the controller". In one embodiment, the duration of each time interval is approximately 100 microseconds.

[0143] In one embodiment, the duration of each time interval corresponds to the period of the pulse width modulation (PWM) cycle.

[0144] In one embodiment, the controller is configured to receive a measured value of the current on the DC bus line and implement current limiting for the current through the power switch circuit by setting or adjusting the PWM duty cycle of one or more drive signals. In one embodiment, the controller is configured to monitor the current through the DC bus line and adjust the PWM duty cycle when the current through the DC bus line exceeds the current limit.

[0145] In one embodiment, the controller is configured to set the current limit according to the voltage rating of one of the AC or DC power supplies.

[0146] In one embodiment, the controller is configured to set the current limit to a first threshold in the AC operation mode and to a second threshold in the DC operation mode so as to reduce the effective power supply to the motor in the AC operation mode to correspond to the operating voltage range of the motor. In this case, the second threshold is higher than the first threshold.

[0147] According to one embodiment, the controller is configured to activate a drive signal within each phase of the motor for a corresponding one of a plurality of power switches within a conduction band (CB) corresponding to the phase of the motor. According to one embodiment, the CB is set to about 120 degrees.

[0148] In one embodiment, the controller is configured to shift the CB by an advance angle (AA) such that the CB precedes the counter electromotive force (EMF) current of the motor. According to one embodiment, the AA is set to about 30 degrees.

[0149] In one embodiment, the controller is configured to set at least one of the CB or the AA according to the voltage rating of one or more of the AC or DC power supplies. In one embodiment, the controller sets at least one of the CB or the AA to a first value with respect to a first nominal voltage when powered by an AC power supply and to a second value different from the first value with respect to a second nominal voltage when powered by a DC power supply.

[0150] In one embodiment, the controller is configured to set the CB to a first CB value in the AC operation mode and to a second CB value greater than the first CB value in the DC operation mode. In one embodiment, the second CB value is determined to increase the effective power supply to the motor in the DC operation mode so as to correspond to the operating voltage range of the motor. In one embodiment, the first CB value is about 120 degrees and the second CB value is greater than about 130 degrees.

[0151] In one embodiment, the controller is configured to set the AA to a first AA value in the AC operation mode and to a second AA value greater than the first AA value in the DC operation mode. In one embodiment, the second AA value is determined to increase the effective power supply to the motor in the DC operation mode so as to correspond to the operating voltage range of the motor. In one embodiment, the first AA value is about 30 degrees and the second AA value is greater than about 35 degrees.

[0152] In one embodiment, the controller is configured to set CB and AA in a coordinated state according to the voltage rating of the AC or DC power supply.

[0153] In one embodiment, the controller is configured to set at least one of CB or AA to a base value corresponding to the maximum speed of the motor at substantially no load, and to gradually increase at least one of CB or AA from the base value to a threshold value with respect to an increase in torque so as to provide a substantially linear speed-torque curve. In one embodiment, the controller is configured to maintain a substantially constant speed on the speed-torque curve. In one embodiment, the base value and the threshold value correspond to a low torque range in which the speed-torque curve is substantially linear. In one embodiment, the controller is configured to maintain at least one of CB or AA at a torque greater than the low torque range.

[0154] According to another aspect of the present invention, there is provided a power tool, the power tool including a brushless direct current (BLDC) motor including a housing and a stator having at least three stator windings corresponding to at least three phases of a rotor and a motor, wherein the rotor is movable by the stator when appropriately energized within the phase corresponding to the stator winding, each phase being characterized by a corresponding voltage waveform for energizing the corresponding stator winding, and the motor being configured to operate within an operating voltage range; a brushless direct current motor; and a motor control circuit configured to receive power from a first power supply having a first nominal voltage or a second power supply having a second nominal voltage different from the first nominal voltage, and to supply power to the motor at a level corresponding to the operating voltage range of the motor. In one embodiment, the first and second power supplies each have an AC power supply or a DC power supply.

[0155] In one embodiment, at least one of the first and second nominal voltages is not substantially corresponding to, different from, or outside the operating voltage range of the motor. In one embodiment, the motor control circuit is configured to optimize the supply of power from at least one of the first or second power supplies to the motor at a level corresponding to the operating voltage range of the motor.

[0156] In one embodiment, the operating voltage range of the motor includes the first nominal voltage but does not include the second nominal voltage. In one embodiment, the operating voltage range of the motor is approximately within the range of 100V to 120V including the first nominal voltage, and the second nominal voltage is approximately within the range of 60V to 100V. In one embodiment, the controller may be configured to increase the effective power supply to the motor so as to correspond to the operating voltage range of the motor when powered by the second power supply.

[0157] In one embodiment, the operating voltage range of the motor includes the second nominal voltage but does not include the first nominal voltage. In one embodiment, the operating voltage range of the motor is approximately in the range of 60V to 100V, which substantially includes the second nominal voltage, and the first nominal voltage is approximately in the range of 100VAC to 120VAC. In one embodiment, when powered by the first power source, the controller may be configured to reduce the effective power supply to the motor so as to correspond to the operating voltage range of the motor.

[0158] In one embodiment, the operating voltage range of the motor does not include either the first nominal voltage or the second nominal voltage. In one embodiment, the motor control circuit is configured to optimize the power supply to the motor from both the first and second power sources at a level corresponding to the operating voltage range of the motor.

[0159] In one embodiment, at least one of the first or second power sources includes an AC power source, and the motor control circuit has a rectifier circuit including a diode bridge. In one embodiment, the rectifier circuit further has a link capacitor arranged in parallel with the diode bridge on the DC bus line. In one embodiment, the diode bridge has a full-wave bridge. In an alternative embodiment, the diode bridge has a half-wave bridge.

[0160] In one embodiment, both the first and second power sources have DC power sources with different nominal voltage levels.

[0161] In one embodiment, the motor control circuit further has a controller configured to control the switching operation of the power switch circuit. In one embodiment, the controller is a programmable device including a microcontroller, a microprocessor, a computer processor, a signal processor. Alternatively, the controller is an integrated circuit configured and customized to control the switching operation of the power switch unit.

[0162] In one embodiment, the power switch circuit has a plurality of power switches including three pairs of high-side and low-side power switches configured as a three-phase bridge circuit connected to the phases of the motor. In one embodiment, the motor control circuit further has a gate driver circuit coupled to the controller and the power switch circuit and configured to drive the gates of the plurality of power switches based on one or more drive signals from the controller. In one embodiment, the motor control circuit further has a power regulator including at least one voltage regulator configured to output a voltage signal to supply power to at least one of the gate driver circuit or the controller. In one embodiment, the motor control circuit further has an on / off switch coupled to at least one of the on / off actuator or the trigger switch and configured to interrupt the supply of power from the power regulator and the gate driver circuit.

[0163] In one embodiment, the power tool further has a plurality of position sensors disposed in the vicinity of the rotor to provide a rotation position signal of the rotor to the control unit. In one embodiment, the controller is configured to control the switching operation of the power switch circuit based on the position signal to appropriately supply energy to the stator windings within the corresponding phase.

[0164] According to one embodiment, within each phase of the motor, the controller is configured to activate a drive signal for a corresponding one of the plurality of power switches within a conduction band corresponding to the phase of the motor.

[0165] In one embodiment, the controller is configured to set a pulse-width modulation (PWM) duty cycle according to a desired motor speed and to control a drive signal to periodically turn on and off a corresponding one of a plurality of power switches within a conduction band to enable variable speed operation of the motor at a constant load according to the PWM duty cycle.

[0166] In one embodiment, the link capacitor has a capacitance value of about 50 μF or less.

[0167] In one embodiment, the controller is configured to control the switching operation of a power switch circuit via one or more drive signals at a fixed pulse-width modulation (PWM) duty cycle, and the controller sets the fixed PWM duty cycle to a first value with respect to a first nominal voltage when powered by a first power supply and to a second value different from the first value with respect to a second nominal voltage when powered by a second power supply.

[0168] In one embodiment, the controller is configured to control the switching operation of a power switch circuit via one or more drive signals at a pulse-width modulation (PWM) duty cycle up to a maximum threshold value, and the controller sets the threshold value to a first value with respect to a first nominal voltage when powered by a first power supply and to a second value different from the first value with respect to a second nominal voltage when powered by a second power supply.

[0169] In one embodiment, when the controller is powered by the first or second power supply so as to correspond to the operating voltage range of the motor, in order to optimize the effective power supply to the motor, when coupled to the first power supply, it controls the switching operation of the power switch circuit within the first duty cycle range, and when coupled to the second power supply, it controls the switching operation of the power switch circuit within the second duty cycle range. In this case, the second PWM duty cycle range is smaller than the first duty cycle range.

[0170] In one embodiment, the controller is configured to receive a measured value of the instantaneous current on the DC bus line, and by comparing the instantaneous current measured value with the current limit, and in response to the instantaneous current measured value exceeding the current limit, to turn off a plurality of power switches for the remaining part of the current time interval to interrupt the current flowing through the electric motor, thereby implementing current limiting for the current through the power switch circuit. In this case, the duration of each time interval is defined as a function of a given frequency at which the electric motor is controlled by the controller.

[0171] In one embodiment, the controller turns on the select power switch at the end point of the current time interval, thereby restarting the flow of current to the motor.

[0172] In one embodiment, the duration of each time interval is approximately 10 times the reciprocal of the given frequency at which the motor is controlled by the controller. In one embodiment, the duration of each time interval is approximately 10 microseconds.

[0173] In one embodiment, the duration of each time interval corresponds to the period of the pulse width modulation (PWM) cycle.

[0174] In one embodiment, the controller is configured to receive a measured value of the current on the DC bus line and to implement current limiting for the current through the power switch circuit by setting or adjusting the PWM duty cycle of one or more drive signals. In one embodiment, the controller is configured to monitor the current through the DC bus line and to adjust the PWM duty cycle when the current through the DC bus line exceeds the current limit.

[0175] In one embodiment, the controller is configured to set the current limit according to the voltage rating of one of the first or second power supplies.

[0176] In one embodiment, the controller is configured to set the current limit to a first threshold when the power tool is powered by the first power supply and to a second threshold when the power tool is powered by the second power supply, so as to optimize the effective power supply from the first or second power supply to the motor corresponding to the operating voltage range of the motor. In this case, the second threshold is higher than the first threshold.

[0177] According to one embodiment, the controller is configured to activate a drive signal within each phase of the motor for a corresponding one of the plurality of power switches within a conduction band (CB) corresponding to the phase of the motor. According to one embodiment, the CB is set to approximately 120 degrees.

[0178] In one embodiment, the controller is configured to shift the CB by an advance angle (AA) such that the CB precedes the back electromotive force (EMF) current of the motor. According to one embodiment, the AA is set to approximately 30 degrees.

[0179] In one embodiment, the controller is configured to set at least one of the CB or AA according to the voltage rating of one or more of the first or second power supplies.

[0180] In one embodiment, the controller is configured to set the CB to a first CB value when the power tool is powered by the first power source and to a second CB value greater than the first CB value when the power tool is powered by the second power source. In one embodiment, the second CB value is determined to increase or decrease the effective power supply to the motor when the power tool is powered by the first or second power source so as to correspond to the operating voltage range of the motor. In one embodiment, the first CB value is about 120 degrees and the second CB value is greater than about 130 degrees.

[0181] In one embodiment, the controller is configured to set the AA to a first AA value when the power tool is powered by the first power source and to a second AA value greater than the first AA value when the power tool is powered by the second power source. In one embodiment, the second AA value is determined to increase or decrease the effective power supply to the motor when the power tool is powered by the first or second power source so as to correspond to the operating voltage range of the motor. In one embodiment, the first AA value is about 30 degrees and the second AA value is greater than about 35 degrees.

[0182] In one embodiment, the controller is configured to set the CB and AA in a coordinated state according to the voltage rating of the first or second power source.

[0183] In one embodiment, the controller is configured to set at least one of CB or AA to a base value corresponding to the maximum speed of the motor in a substantially no-load state, and to gradually increase at least one of CB or AA from the base value to a threshold value with respect to an increase in torque so as to provide a substantially linear speed-torque curve. In one embodiment, the controller is configured to maintain a substantially constant speed on the speed-torque curve. In one embodiment, the base value and the threshold value correspond to a low torque range in which the speed-torque curve is substantially linear. In one embodiment, the controller is configured to maintain at least one of CB or AA at a torque greater than the low torque range.

[0184] In another aspect, the battery pack is bidirectionally convertible between a low rated voltage / high capacity configuration and an intermediate rated voltage / low capacity configuration.

[0185] In another aspect, the power tool system includes a battery pack that is bidirectionally convertible between a low rated voltage / high capacity configuration and an intermediate rated voltage / low capacity configuration, and a power tool coupled to the battery pack that converts the battery pack from the low rated voltage / high capacity configuration to the intermediate rated voltage / low capacity configuration and operates with the battery pack in the intermediate rated voltage / low capacity configuration.

[0186] In another aspect, the power tool system includes a battery pack that is bidirectionally convertible between a low rated voltage / high capacity configuration and an intermediate rated voltage / low capacity configuration, a first power tool coupled to the battery pack that converts the battery pack from the low rated voltage / high capacity configuration to the intermediate rated voltage / low capacity configuration and operates with the battery pack in the intermediate rated voltage / low capacity configuration, and a second power tool coupled to the battery pack that operates with the battery pack in the low rated voltage / high capacity configuration.

[0187] In another aspect, the power tool system includes a first battery pack that is bidirectionally convertible between a low-rated voltage / high-capacity configuration and an intermediate-rated voltage / low-capacity configuration, a second battery pack that is always in the low-rated voltage / high-capacity configuration, and a power tool that is coupled to the first battery pack and operates with the first battery pack in its low-rated voltage / high-capacity configuration, and is also coupled to the second battery pack and operates with the second battery pack in its low-rated voltage / high-capacity configuration.

[0188] In another aspect, the power tool system includes a first battery pack that is bidirectionally convertible between a low-rated voltage / high-capacity configuration and an intermediate-rated voltage / low-capacity configuration, a second battery pack that is always in the low-rated voltage / high-capacity configuration, a first power tool that is coupled to the first battery pack and operates with the first battery pack in its low-rated voltage / high-capacity configuration, and is also coupled to the second battery pack and operates with the second battery pack in its low-rated voltage / high-capacity configuration, and a second power tool that is coupled to the first battery pack but not to the second battery pack and operates with the first battery pack in its high-rated voltage / low-capacity configuration.

[0189] In another aspect, the power tool system includes a battery pack that is bidirectionally convertible between a low-rated voltage / high-capacity configuration and an intermediate-rated voltage / low-capacity configuration, a first intermediate-rated voltage power tool that is coupled to the battery pack, converts the battery pack from the low-rated voltage / high-capacity configuration to the intermediate-rated voltage / low-capacity configuration, and operates with the battery pack in its intermediate-rated voltage / low-capacity configuration, and a second high-rated voltage power tool that is coupled to a plurality of battery packs, converts each battery pack from the low-rated voltage / high-capacity configuration to the intermediate-rated voltage / low-capacity configuration, and operates with the battery packs in their intermediate-rated voltage / low-capacity configurations.

[0190] In another aspect, the power tool system includes a battery pack that is bidirectionally convertible between a low-rated voltage / high-capacity configuration and an intermediate-rated voltage / low-capacity configuration, coupled to a plurality of battery packs, converting each battery pack from the low-rated voltage / high-capacity configuration to the intermediate-rated voltage / low-capacity configuration, and / or coupled to a high-rated voltage AC power source, together with the battery packs and / or the high-rated voltage AC power source in their intermediate-rated voltage / low-capacity configuration, a high-rated voltage power tool that operates at a high-rated voltage.

[0191] In another aspect, the first battery pack is bidirectionally convertible between a low-rated voltage / high-capacity configuration and an intermediate-rated voltage / low-capacity configuration, the second battery pack is always in the low-rated voltage / high-capacity configuration, and a battery pack charger electrically and mechanically connectable to the first battery pack and the second battery pack can charge both the first battery pack and the second battery pack.

[0192] In another aspect, the battery pack includes a housing and a battery present within the housing. The battery may include a plurality of rechargeable cells and a switching network coupled to the plurality of rechargeable cells. The switching network may have a first configuration and a second configuration. The switching network may be switchable from the first configuration to the second configuration and from the second configuration to the first configuration. The plurality of rechargeable cells may be in the first configuration when the switching network is in the first configuration and in the second configuration when the switching network is in the second configuration. The second configuration is different from the first configuration.

[0193] The switching network of the battery pack of this embodiment may have a third configuration. In this case, when the switching network is in the third configuration, the plurality of rechargeable cells are in the third configuration. The switching network of the battery pack of this embodiment may be switched between the first configuration and the second configuration by an external input to the battery pack. The first configuration of the rechargeable cells of the battery pack of this embodiment may be a relatively low voltage and high capacity configuration, and the second configuration of the rechargeable cells of the battery pack may be a relatively high voltage and low capacity configuration. The battery pack of this embodiment may include a cell configuration in which the first configuration provides a first rated pack voltage and the second configuration provides a second rated pack voltage. In this case, the first rated pack voltage is different from the second rated pack voltage. The third configuration of the battery pack of this embodiment may be an open circuit configuration.

[0194] The rechargeable cells of the battery pack in the first configuration may enter the third configuration during the conversion between the first and second configurations. The battery pack of this embodiment may have a terminal block coupled to the plurality of rechargeable cells and the switching network. In this case, the terminal block receives a switching element for switching the switching network from the first configuration to the second configuration.

[0195] In another aspect, the battery pack has a housing and a battery present within the housing. The battery may include a set P of O rechargeable cells Q, where O is a number ≧ 2. The set P of rechargeable cells Q may include N subsets R of cells Q, where N is a number ≧ 2. Each subset R of cells Q may include M cells Q, where M is a number ≧ 1, and where M × N = O. The battery may include a switching network coupled to the rechargeable cells, in which case the switching network may have a first configuration and a second configuration and may be switchable from the first configuration to the second configuration and from the second configuration to the first configuration. All of the subsets R of rechargeable cells Q may be connected in parallel when the switching network is in the first configuration and may be separated when the switching network is in the second configuration. The first power terminal may be coupled to the positive terminal of cell Q1, and the second power terminal may be coupled to the negative terminal of QO, in which case the first and second power terminals provide power externally from the battery pack. A negative conversion terminal may be coupled to the negative terminals of each of the subsets R1 to RN-1, and a positive conversion terminal may be coupled to the positive terminals of each of the subsets R2 to RN. The negative conversion terminal and the positive conversion terminal of the battery pack of this embodiment are accessible from outside the battery housing.

[0196] In another aspect, the battery pack has a housing and a battery present within the housing. The battery of this embodiment may include the battery present within the housing. The battery of this embodiment may include a set P of O rechargeable cells Q, where O is a number ≧ 2. The set P of rechargeable cells Q may include N subsets R of cells Q, where N is a number ≧ 2. Each subset R of cells Q may include M cells Q, where M is a number ≧ 1 and M×N = O. The battery pack of this embodiment may include a switching network coupled to the rechargeable cells. The switching network may have a first configuration and a second configuration and may be switchable from the first configuration to the second configuration and from the second configuration to the first configuration. All of the subsets R of the rechargeable cells Q may be connected in parallel when the switching network is in the first configuration and may be separated when the switching network is in the second configuration. The battery pack may include a first power terminal coupled to the positive terminal of Q1 and a second power terminal coupled to the negative terminal of QO, in which case the first and second power terminals provide power externally from the battery pack. The battery pack may include a negative conversion terminal coupled to the negative terminal of each subset of cells and a positive conversion terminal coupled to the positive terminal of each subset of cells.

[0197] In another aspect, the power tool has a first power source from an AC input having a rated AC voltage, a second power source from a plurality of rechargeable battery cells having a rated DC voltage, a motor connectable to the first and second power sources, and a control circuit configured to operate the motor with substantially the same output power when operated by the first and second power sources. The rated DC voltage of the power tool of this embodiment may be approximately equal to the rated AC voltage. The motor of the power tool of this embodiment is a brushed motor. The control circuit of the power tool of this embodiment may operate the brushed motor at a constant no-load speed regardless of whether the motor is operating by the first power source or the second power source. The control circuit of the power tool of this embodiment may operate the brushed motor at a variable no-load speed based on a user input. The control circuit of the power tool of this embodiment may include an IGBT / MOSFET circuit configured to operate the motor at a variable no-load speed using the first power source or the second power source. The motor of the power tool of this embodiment may be a brushless motor. The control circuit of the power tool of this embodiment may have a small capacitor and a per-cycle current limiter. The rated DC voltage of the power tool of this embodiment may be less than the rated AC voltage. The control circuit of the power tool of this embodiment may have a small capacitor and a per-cycle current limiter. The control circuit of the power tool of this embodiment may have at least one of an advance angle control device and a conduction band control device. The control circuit of the power tool of this embodiment may detect whether the first and second power sources are activated. The control circuit of the power tool of this embodiment may always select the first power source when the first power source is active. The control circuit of the power tool of this embodiment may switch to the second power source when the first power source stops. The control circuit of the power tool of this embodiment may include a boost mode in which the control circuit operates the power source at a greater output power using both the first and second power sources simultaneously. The power source of the power tool of this embodiment may be provided by a cord set.The first power source and the second power source of the power tool according to this embodiment may simultaneously supply power to the motor, or may supply substantially greater power than that which can be individually supplied by the first or second power source.

[0198] In another aspect, the power tool has an input for receiving power from an AC power source, an input for receiving power from a rechargeable DC power source, a charger for charging the rechargeable DC power source by the AC power source, and a motor configured to be powered by at least one of the AC power source and the rechargeable DC power source. The AC power source of the power tool according to this embodiment may be a commercial power line. The rechargeable DC power source of the power tool according to this embodiment may be a removable battery pack.

[0199] In another embodiment, the power tool has an input for receiving AC power from an AC power source, where the AC power source has a rated AC voltage and is located outside the power tool, and an input for receiving DC power from a DC power source, where the DC power source has a rated DC voltage and is a plurality of rechargeable battery cells, and the rated DC voltage is approximately equal to the rated AC voltage, and a motor configured to be powered by at least one of the AC power source and the DC power source. The AC power source of the power tool according to this embodiment may be a commercial power line. The rechargeable DC power source of the power tool according to this embodiment may be a battery pack. The AC power source and the DC power source of the power tool according to this embodiment may have a rated voltage of 120 volts.

[0200] In another aspect, the power tool has a motor, a first power source from an AC input line, and a second power source from a rechargeable battery, where the second power source provides power substantially equivalent to that of the first power source. The first power source and the second power source of the power tool according to this embodiment may simultaneously supply power to the motor. The first power source and the second power source of the power tool according to this embodiment may alternately supply power to the motor.

[0201] In another aspect, the power tool has a motor, a first power source from an AC input line, and a second power source from a rechargeable battery, the second power source providing power substantially equivalent to the power of the first power source. The first power source and the second power source of the power tool in this embodiment may simultaneously provide power to the motor. The first power source and the second power source of the power tool in this embodiment may alternately provide power to the motor.

[0202] In another aspect, the battery pack may include a housing, a plurality of cells, and a converter element, the converter element being movable between a first position in which the plurality of cells are configured to provide a first rated voltage and a second position in which the plurality of cells are configured to provide a second rated voltage different from the first rated voltage.

[0203] Embodiments of this aspect may include one or more of the following features. In the case of the battery pack described above, the converter element has a housing and a plurality of contacts. In the case of the battery pack described above, the housing forms an internal cavity, and the plurality of cells are housed within the internal cavity. In the case of the battery pack described above, the housing forms an internal cavity, the converter element is housed within the internal cavity, and is accessible from outside the housing. The battery pack described above further has a battery having a plurality of cells and a converter element, and a switching network. In the case of the battery pack described above, the housing further has an external slot and a through hole at a first end of the slot, and the through hole extends from the external surface of the housing to the internal cavity of the housing. In the case of the battery pack described above, the converter element further has a protrusion extending through the through hole and a plurality of contacts. In the case of the battery pack described above, the converter element has a jumper switch. The battery pack further has a battery having a plurality of cells, a plurality of conductive contact pads, and nodes between adjacent electrically connected cells, each of the plurality of conductive contact pads being coupled to a single node, the converter element including a plurality of contacts, (a) when the converter element is in a first position, each of the plurality of converter element contacts is electrically connected to a first set of the plurality of conductive contact pads, each of the plurality of conductive contact pads being within a single first set of the plurality of conductive contact pads, and (b) when the converter element is in a second position, each of the converter element contacts is electrically connected to a second set of the plurality of conductive contact pads, each second set of the plurality of conductive contact pads being different from all other second sets of the plurality of conductive contact pads, and each first set of the plurality of conductive contact pads being different from each second set of the plurality of conductive contact pads.The battery pack described above further includes a battery having a plurality of cells, a plurality of conductive contact pads, and nodes between adjacent electrically connected cells, wherein each of the plurality of conductive contact pads is coupled to a single node. In this case, when the converter element is in the first position, each of the plurality of converter element contacts is a shunt between the conductive contact pads within a corresponding first set of the plurality of conductive contact pads, and when the converter element is in the second position, each of the plurality of converter element contacts is a shunt between the conductive contact pads within a corresponding second set of the plurality of conductive contact pads.

[0204] In another aspect, the battery pack includes a housing, a plurality of cells, and a converter element, wherein the converter element is movable between a first position in which the plurality of cells are electrically connected in a first cell configuration and a second position in which the plurality of cells are electrically connected in a second cell configuration, and the first cell configuration is different from the second cell configuration.

[0205] Embodiments of this aspect may include one or more of the following features. In the battery pack described above, the converter element has a housing and a plurality of contacts. In the battery pack described above, the housing forms an internal cavity, and the plurality of cells are housed within the internal cavity. In the battery pack described above, the housing forms an internal cavity, the converter element is housed within the internal cavity and is accessible from outside the housing. In the battery pack described above, it further has a battery having a plurality of cells and a converter element, and a switching network. In the battery pack described above, the housing further has an external slot and a through hole at a first end of the slot, and the through hole extends from the external surface of the housing to the internal cavity of the housing. In the battery pack described above, the converter element further has a protrusion extending through the through hole and a plurality of contacts. In the battery pack described above, the converter element has a jumper switch. In the battery pack described above, it further has a battery having a plurality of cells, a plurality of conductive contact pads, and nodes between adjacent electrically connected cells, where each of the plurality of conductive contact pads is connected to a single node, and in this case, the converter element includes a plurality of contacts, (a) when the converter element is in a first position, each of the plurality of converter element contacts is electrically connected to a first subset of the plurality of conductive contact pads, and (b) when the converter element is in a second position, each of the plurality of converter element contacts is electrically connected to a second subset of the plurality of conductive contact pads, and the second subset of the plurality of conductive contact pads is different from the first subset of the plurality of conductive contact pads.The battery pack further includes a battery having a plurality of cells, a plurality of conductive contact pads, and nodes at the junctions between adjacent electrically connected cells, wherein each of the plurality of conductive contact pads is coupled to a single node. In this case, when the converter element is in the first position, each of the plurality of converter element contacts is a shunt between the conductive contact pads within a first subset of the plurality of conductive contact pads, and when the converter element is in the second position, each of the plurality of converter element contacts is a shunt between the conductive contact pads within a second subset of the plurality of conductive contact pads.

[0206] In another aspect, the battery pack includes a housing, a set of cells having at least two cells, two subsets of the set of cells, where each cell of the set of cells is within a single subset, each subset of cells is electrically connected in series and has a positive node and a negative node, a switching network having a first switch connecting the positive end of the first subset to the positive end of the second subset, a second switch connecting the negative end of the first subset to the negative end of the second subset, and a third switch connecting the negative end of the first subset to the positive end of the second subset, and a converter element operating with the switching network to open and close the first, second, and third switches to convert the set of cells between a low voltage configuration and an intermediate voltage configuration.

[0207] In another aspect, the battery pack includes a housing, a cell assembly having at least two cells, two subsets of the cell assembly, each cell of the cell assembly being within a single subset, each subset of cells being electrically connected in series and having a positive node and a negative node, a switching network having a first switch connecting the positive end of the first subset to the positive end of the second subset, a second switch connecting the negative end of the first subset to the negative end of the second subset, and a third switch connecting the negative end of the first subset to the positive end of the second subset, and a converter element operating with the switching network to configure the first, second, and third switches in a first state in which the cell assembly is electrically connected in a first cell configuration and in a second state in which the cell assembly is electrically connected in a second cell configuration, the first cell configuration being different from the second cell configuration.

[0208] Embodiments of this aspect may include one or more of the following features. In the battery pack described above, the converter element operates when the battery pack is coupled to an electrical device. In the battery pack described above, the converter element has a set of terminals and operates when the battery pack is coupled to an electrical device.

[0209] In another aspect, a combination of an electrical device and a battery pack is a battery pack comprising: (1) a housing including a battery pack interface; (2) a plurality of cells; and (3) a converter element movable between a first position in which the plurality of cells are configured to provide a first rated voltage and a second position in which the plurality of cells are configured to provide a second rated voltage different from the first rated voltage. The combination further includes an electrical device including a housing, the housing including an electrical device interface configured to couple to the battery pack interface for mechanically coupling the electrical device to the battery pack, the electrical device interface including a conversion function for moving the converter element from the first position to the second position when the electrical device is mechanically coupled to the battery pack.

[0210] Embodiments of this aspect may include one or more of the following features. In the combination, the converter element has a plurality of battery terminals, and the conversion function has a plurality of electrical device terminals. In the combination described above, the converter element has a housing and a plurality of contacts. In the combination described above, the housing forms an internal cavity, and the plurality of cells are housed within the internal cavity. In the combination described above, the housing forms an internal cavity, and the converter element is housed within the internal cavity. The combination further includes a battery including a plurality of cells. In the combination, the electrical device is a power tool. In the combination described above, the electrical device is a charger. In the combination described above, the electrical device is a battery holding tray.

[0211] In another aspect, a battery pack includes a housing, a plurality of cells, and a first set of terminals electrically coupled to the plurality of cells, the first set of terminals providing output power, and a second set of terminals electrically coupled to a set of the plurality of cells, the second set of terminals configured to enable conversion of the plurality of cells between a first configuration and a second configuration.

[0212] Embodiments of this aspect may include one or more of the following features. In the battery pack described above, the housing forms a cavity, and the plurality of cells, the first set of terminals, and the second set of terminals are housed within the internal cavity. In the battery pack described above, it further has a battery having a plurality of cells. In the battery pack described above, the second set of terminals includes a set of switches. In the battery pack described above, the second set of terminals is configured to receive a switching device that enables the switches to convert the plurality of cells from a first configuration to a second configuration. In the battery pack described above, the second set of terminals is configured to convert the plurality of cells from a first configuration to a second configuration when receiving the switching device. In the battery pack described above, the plurality of cells are converted from a first configuration to a second configuration when the second set of terminals receives the switching device. In the battery pack described above, the second set of terminals is configured to enable conversion of the plurality of cells to a third configuration. In the battery pack described above, the plurality of cells enter the third configuration during switching from the first and second configurations.

[0213] In another aspect, a combination of a battery pack and an electrical device has: (a) a battery pack having a housing, a plurality of cells, a first set of battery terminals electrically coupled to the plurality of cells, the first set of terminals providing output power, and a second set of battery terminals electrically coupled to the plurality of cells, the second set of terminals being configured to allow the plurality of cells to be converted from a first configuration to a second configuration; and (b) a first set of electrical device terminals configured to be electrically coupled to the first set of battery terminals, and an electrical device having a converter element configured to be electrically coupled to the second set of battery terminals to enable conversion of the plurality of cells from the first configuration to the second configuration.

[0214] Embodiments of this aspect may include one or more of the following features. In the battery pack described above, it further has a battery including a plurality of cells. In the battery pack described above, the electrical device is a power tool having a motor, and the first set of power tool terminals is configured to be electrically coupled to the motor and electrically coupled to the first set of battery terminals, and the first set of tool terminals provides input power. In the battery pack described above, the electrical device is a charger. In the battery pack described above, the electrical device is a battery holder.

[0215] In another aspect, the battery pack includes a housing, a plurality of cells, and a set of connection terminals, and the connection terminals are movable between a first position where the plurality of cells are configured to provide a first rated voltage and a second position where the plurality of cells are configured to provide a second rated voltage different from the first rated voltage.

[0216] In another aspect, the battery pack includes a housing, a plurality of cells, and a set of connection terminals, and the connection terminals are movable between a first terminal configuration in which the plurality of cells are electrically connected in a first cell configuration and a second terminal configuration in which the plurality of cells are electrically connected in a second cell configuration, and the first cell configuration is different from the second cell configuration.

[0217] In another aspect, the convertible battery pack has a housing, a plurality of cells, a set of battery terminals, and a conversion subsystem, and the conversion subsystem has a converter element, and the converter element is movable between a first position where the plurality of cells are configured to provide a first rated voltage at the set of battery terminals and a second position where the plurality of cells are configured to provide a second rated voltage at the set of battery terminals, and the second rated voltage is different from the first rated voltage.

[0218] Embodiments of this aspect may include one or more of the following features. In the battery pack of this exemplary embodiment, the converter element has a housing and a plurality of contacts, the housing forms an internal cavity, and a plurality of cells are housed within the internal cavity. In this exemplary embodiment, the converter element is housed within the internal cavity and is accessible from outside the housing. In this exemplary embodiment, the battery pack further has a battery having a plurality of cells, and the conversion subsystem has a converter element and a switching network. In this exemplary embodiment, the battery pack further has an external slot and a through hole at a first end of the slot, and the through hole extends from the external surface of the housing to the internal cavity of the housing. In the battery pack of this exemplary embodiment, the converter element further has a protrusion extending through the through hole and a plurality of contacts. In the battery pack of this exemplary embodiment, the switching network of the conversion subsystem includes a switch for sending a power current through a second set of battery terminals. In this exemplary embodiment, the set of battery terminals of the battery pack further has a first set of battery terminals electrically coupled to the plurality of cells and a second set of battery terminals electrically coupled to the plurality of cells, the first set of battery terminals being configured to provide power when the battery pack is in a first rated voltage configuration and a second rated voltage configuration, and the second set of battery terminals being configured to provide power only when the battery pack is in the second rated voltage configuration.

[0219] In another aspect, an exemplary embodiment of a convertible battery pack has a housing, a plurality of cell strings, and a conversion subsystem, the conversion subsystem having a converter element, where the converter element is movable between a first position where the plurality of cell strings are electrically connected in a first cell configuration and a second position where the plurality of cell strings are electrically connected in a second cell configuration, and the first cell configuration is different from the second cell configuration.

[0220] Embodiments of this aspect may include one or more of the following features. In the battery pack of this exemplary embodiment, the converter element has a housing and a plurality of contacts, the housing forms an internal cavity, and the plurality of cell strings are accommodated within the internal cavity. In the battery pack of this exemplary embodiment, the converter element is accommodated within the internal cavity and is accessible from outside the housing. This exemplary battery pack further has a battery having a plurality of cell strings and a converter element, and a switching network. In the battery pack of this exemplary embodiment, the housing further has an external slot and a through hole at a first end of the slot, and the through hole extends from the external surface of the housing to the internal cavity of the housing. In the battery pack of this exemplary embodiment, the converter element further has a protrusion extending through the through hole and a plurality of contact pads. In the battery pack of this exemplary embodiment, the converter element has a plurality of switching contacts.

[0221] In another aspect, an exemplary embodiment of a convertible battery pack has a housing, a set of cells, the set of cells having two cell strings, each cell string of the cells having at least one cell, the cells of each cell string being electrically connected in series, each cell string of the cells having a positive terminal and a negative terminal, a first switch connecting the positive terminal of the first cell string to the positive terminal of the second cell string, a second switch connecting the negative terminal of the first cell string to the negative terminal of the second cell string, and a third switch connecting the negative terminal of the first cell string to the positive terminal of the second cell string, a switching network having a converter element operating with the switching network to open and close the first, second, and third switches so as to convert the set of cells between a low-rated voltage configuration and an intermediate-rated voltage configuration.

[0222] In another aspect, an exemplary embodiment of a convertible battery pack includes a housing and a cell assembly, the cell assembly having two strings of cells, each string of cells having at least one cell, the cells of each string of cells being electrically connected in series, each string of cells having a positive terminal and a negative terminal, a cell assembly, a first switch connecting the positive terminal of the first string of cells to the positive terminal of the second string of cells, a second switch connecting the negative terminal of the first string of cells to the negative terminal of the second string of cells, and a third switch connecting the negative terminal of the first string of cells to the positive terminal of the second string of cells, a switching network having a first, a second, and a third switch, and, in operation, a converter element operating with the switching network to configure the first, second, and third switches to a first state in which the cell assembly is electrically connected in a first cell configuration and a second state in which the cell assembly is electrically connected in a second cell configuration, the first cell configuration being different from the second cell configuration.

[0223] Embodiments of this aspect may include one or more of the following features. In the battery pack of this exemplary embodiment, the converter element operates when the battery pack is coupled to an electrical device and has a set of switching contacts.

[0224] In another aspect, an exemplary embodiment of a combination of an electrical device and a convertible battery pack is a battery pack comprising: (1) a housing including a battery pack interface; (2) a plurality of cells; and (3) a converter element movable between a first position where the plurality of cells are configured to provide a first rated voltage and have a first capacity, and a second position where the plurality of cells are configured to provide a second rated voltage and have a second capacity, the second rated voltage and the second capacity being different from the first rated voltage and the first capacity, and an electrical device including a housing, the housing including an electrical device interface configured to couple the electrical device mechanically to the battery pack interface, the electrical device interface including a conversion function for moving the converter element from the first position to the second position when the electrical device is mechanically coupled to the battery pack.

[0225] Embodiments of this aspect may include one or more of the following features. This exemplary convertible battery pack further has a first set of battery pack terminals for providing power to a load of the electrical device and a second set of battery pack terminals for providing power to a load of the electrical terminals.

[0226] In another aspect, an exemplary embodiment of a convertible battery pack is a battery pack having a housing, a plurality of cells, a first set of battery pack terminals electrically coupled to the plurality of cells and configured to provide output power, and a second set of battery pack terminals electrically coupled to the plurality of cells and configured to enable conversion of the plurality of cells between a first configuration and a second configuration.

[0227] Embodiments of this aspect may include one or more of the following features. In the battery pack of this exemplary embodiment, the second set of battery pack terminals is electrically coupled to a set of switches. In the battery pack of this exemplary embodiment, when the set of switches is in the first state, the second set of battery pack terminals is configured to enable a plurality of cells to be converted from a first configuration to a second configuration. In the battery pack of this exemplary embodiment, when receiving a switching device, the set of switches is arranged in the first state. In the battery pack of this exemplary embodiment, when the set of switches is in the first state, the second set of battery pack terminals is configured to transfer a power current from the battery pack to a coupled electrical device. In the battery pack of this exemplary embodiment, the plurality of cells are converted from a first configuration to a second configuration when the battery pack receives a conversion element.

[0228] In another aspect, an exemplary embodiment of a combination of a battery pack and an electrical device includes: (a) a battery pack having a housing, a plurality of cells, a first set of battery pack terminals electrically coupled to the plurality of cells, and a second set of battery pack terminals electrically coupled to the plurality of cells, the plurality of cells being configurable to provide a first rated voltage and a second rated voltage, the first set of battery pack terminals being configured to provide power when the battery pack is in a first rated voltage configuration and a second rated voltage configuration, and the second set of battery pack terminals being configured to provide power only when the battery pack is in a second rated voltage configuration; and (b) an electrical device having a first set of electrical device terminals configured to be electrically coupled to the first set of battery pack terminals and a second set of electrical device terminals configured to be electrically coupled to the second set of battery pack terminals to provide power to a load of the electrical device. In the exemplary combination, the electrical device includes a conversion element for converting the battery pack from a first rated voltage to a second rated voltage.

[0229] Embodiments of this aspect may include one or more of the following features. In an exemplary combination, the electrical device is a power tool having a motor, and a first set of power tool terminals is configured to be electrically coupled to the motor and to be electrically coupled to a first set of battery pack terminals, and the first set of tool terminals provides input power.

[0230] In another aspect, an exemplary embodiment of a combination of a battery pack and an electrical device includes: (a) a battery pack having a housing, a plurality of cells, a first set of battery pack terminals electrically coupled to the plurality of cells, and a second set of battery pack terminals electrically coupled to the plurality of cells, the plurality of cells being configurable to provide a first rated voltage and a second rated voltage, the first set of battery pack terminals being configured to provide power when the battery pack is in a first rated voltage configuration and a second rated voltage configuration, and the second set of battery pack terminals being configured to provide power only when the battery pack is in a second rated voltage configuration; and (b) a charger having a first set of charger terminals configured to be electrically coupled to the first set of battery pack terminals and a second set of charger terminals configured to be electrically coupled to the second set of battery pack terminals to provide power from the charger to the plurality of cells. In an exemplary combination, the charger includes a conversion element for converting the battery pack from a first rated voltage to a second rated voltage.

[0231] Advantages may include one or more of the following. The power tool system may enable a power tool system with sufficient compatibility including low-power, mid-power, and high-power cordless power tools and high-power AC / DC power tools. The convertible battery pack may enable system backward compatibility with existing power tools. The system may include a power supply tool with a DC rated voltage corresponding to the rated voltage of an AC commercial power supply for high-power operation of a power tool using battery pack power. These and other advantages and features will become apparent from the specification, drawings, and claims.

Brief Description of the Drawings

[0232]

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Best Mode for Carrying Out the Invention

[0233] I. Power Tool System Referring to Figure 1A, in one embodiment, the power tool system 1 includes a set of power tools 10 (including a DC power tool 10A and an AC / DC power tool 10B), a set of power sources 20 (including a DC battery pack power source 20A and an AC power source 20B), and a set of battery pack chargers 30. Each of the power tool, the power source, and the battery pack charger can be expressed as having a rated voltage. The rated voltage used in this application can mean one or more of the advertised voltage, the operating voltage, the nominal voltage, or the maximum voltage depending on the context. Also, the rated voltage can include a single voltage, several individual voltages, or one or more ranges of voltages. The rated voltage used in this application can mean any of these types of voltages or a range of any of these types of voltages.

[0234] Published voltage: For power tools, battery packs, and chargers, the published voltage generally means the voltage displayed by the manufacturer or seller on the labels, packaging, user manuals, instructions, advertisements, marketing, or other support documents for these products so that the user is notified of which power tools, battery packs, and chargers will operate with each other. The published voltage may include a numerical voltage value that notifies the user of which power tools, battery packs, and chargers will operate with each other, or may include another word, phrase, alphanumeric combination, icon, or logo. In some embodiments, as described below, a power tool, battery pack, or charger may have a single published voltage (e.g., 20V), a range of published voltages (e.g., 20V to 60V), or multiple separate published voltages (e.g., 20V / 60V). Also, as described further below, a power tool may be advertised or labeled with a notation (e.g., AC / DC or AC / 60V) that notifies that it will operate with both DC and AC power sources. Also, an AC power source may also be expressed as having a published voltage, which is the voltage that is generally known as the AC commercial power supply voltage in a given country (e.g., 120VAC in the United States and 220VAC to 240VAC in Europe).

[0235] Operating Voltage: In the case of power tools, the operating voltage generally means the voltage or range of voltages of one or more AC and / or DC power supplies for which the power tool, its motor, and its electronic components are designed to operate. For example, a power tool advertised as a 120VAC / DC tool may have an operating voltage range of 92V to 132V. Also, the operating voltage of a power tool can mean the aggregate of the operating voltages of multiple power supplies connected to the power tool (e.g., a 120V power tool may be operable using two 60V battery packs connected in series). In the case of battery packs and chargers, the operating voltage means the DC voltage or range of DC voltages for which the battery pack or charger is designed to operate. For example, a battery pack or charger advertised as a 20V battery pack or charger may have an operating voltage range of 17V to 19V. In the case of an AC power supply, the operating voltage can mean the root-mean-square (RMS) of the voltage value of the AC waveform and / or the average voltage within each positive half-cycle of the AC waveform. For example, a 120VAC commercial power supply can be expressed as having an RMS operating voltage of 120V and an average positive operating voltage of 108V.

[0236] Nominal Voltage: In the case of a battery pack, the nominal voltage generally means the average DC voltage output from the battery pack. For example, a battery pack advertised as a 20V battery pack with an operating voltage of 17V to 19V may have a nominal voltage of 18V. In the case of an AC power supply, the operating voltage can mean the root-mean-square (RMS) of the voltage value of the AC waveform and / or the average voltage within each positive half-cycle of the AC waveform. For example, a 120VAC commercial power supply can be expressed as having an RMS nominal voltage of 120V and an average positive nominal voltage of 108V.

[0237] Maximum Voltage: In the case of a battery pack, the maximum voltage can mean the fully charged voltage of the battery pack. For example, a battery pack advertised as a 20V battery pack may have a fully charged maximum voltage of 20V. In the case of a charger, the maximum voltage can mean the maximum voltage at which the battery pack can be charged by the charger. For example, a 20V charger may have a maximum charging voltage of 20V.

[0238] Also, certain components of the power tool, battery pack, and charger may be expressed as having a voltage rating, and it should also be noted that each of them may mean one or more of the published voltage, operating voltage, nominal voltage, or maximum voltage. The rated voltage of each of these components may include a single voltage, several separate voltages, or one or more ranges of voltages. These voltage ratings may be the same as, or different from, the rated voltages of the power tool, battery pack, and charger. For example, the motor of a power tool may be expressed as having its own operating voltage or range of voltages designed for the motor to operate. The rated voltage of the motor may be the same as, or different from, the operating voltage or voltage range of the power tool. For example, a power tool having a voltage rating of 60V to 120V may have a motor with an operating voltage of 60V to 120V or a motor with an operating voltage of 90V to 100V.

[0239] Also, the power tool, power source, and charger may have ratings for characteristics other than voltage. For example, the power tool may have ratings for motor performance such as output power (e.g., maximum watts out (MWO) described in U.S. Patent No. 7,497,275 incorporated by reference) or the speed of the motor under a given load condition. In another example, the battery pack may have a rated capacity, which means the total energy stored in the battery pack. The rated capacity of the battery pack may depend on the rated capacity of the individual cells and the way the cells are electrically connected.

[0240] Also, this application refers to the ratings of voltage (and other characteristics) by using relative terms such as low, medium, high, and extremely high. The terms low rating, medium rating, high rating, and extremely high rating are relative terms used to indicate the relative relationships among the various ratings of power tools, battery packs, AC power supplies, chargers, and their components, and are not intended to be limited to any specific numerical value or range. For example, it should be understood that a low-rated voltage is generally lower than a medium-rated voltage, a medium-rated voltage is generally lower than a high-rated voltage, and a high-rated voltage is generally lower than an extremely high-rated voltage. In a particular embodiment, different rated voltages may be integer multiples or divisors of each other. For example, the medium-rated voltage may be an integer multiple of the low-rated voltage, and the high-rated voltage may be an integer multiple of the medium-rated voltage. For example, the low-rated voltage may be 20V, the medium-rated voltage may be 60V (3 × 20V), and the high-rated voltage may be 120V (2 × 60V and 6 × 20V). In this application, the notation "XY" may often be used as a general notation for the terms low, medium, high, and extremely high.

[0241] In some examples, a power tool, power supply, or charger may be described as having multiple rated voltages. For example, a power tool or battery pack may have a low / medium rated voltage or a medium / high rated voltage. As will be described in more detail later, these multiple ratings mean a power tool, power supply, or charger having multiple maximum, nominal, or actual voltages, or multiple published voltages, or configured to operate with two or more power tools, battery packs, AC power supplies, or chargers having different rated voltages. For example, a medium / high rated voltage power tool may be labeled as having medium and high voltages and may be configured to operate with a medium-rated voltage battery pack or a high-rated voltage AC power supply. It should be understood that multiple rated voltages can mean that the rated voltage has a range spanning two different rated voltages, or that the rated voltage has two separate and different rated values.

[0242] Also, this application often refers to a first one of a power tool, a power source, a charger, or components thereof as having a first rated voltage that corresponds to, matches, or is equivalent to a second rated voltage of a second one of a power tool, a power source, a charger, or components thereof. This comparison generally means a first rated voltage having one or more values or one or more value ranges that are substantially equal to, overlap, or are included in one or more values or one or more value ranges of the second rated voltage, or that the first one of the power tool, the power source, the charger, or the component is configured to operate with the second one of the power tool, the power source, the charger, or components thereof. For example, an AC / DC power tool having a rated voltage of 120V (published) or 90V - 132V (operating) may correspond to a pair of battery packs having a total rated voltage of 120V (published and maximum), 108V (nominal), or 102V - 120V (operating), or may correspond to some AC power sources having a rated voltage in the range of 100VAC - 120VAC.

[0243] Conversely, the present application often refers to a first one of a power tool, a power source, a charger, or components thereof as having a first rated voltage that does not correspond to, is different from, or is not equivalent to the second rated voltage of a second one of a power tool, a power source, a charger, or components thereof. These comparisons generally mean a first rated voltage having one or more values or one or more value ranges that are not equal to, do not overlap with, or are not included in one or more values or one or more value ranges of the second rated voltage, or that a first one of a power tool, a power source, a charger, or components thereof is not configured to operate with a second one of a power tool, a power source, a charger, or components thereof. For example, an AC / DC power tool having a rated voltage of 120V (published) or 90V to 132V (operating) may not correspond to a battery pack having a total rated voltage of 60V (published and maximum), 54V (nominal), or 51V to 60V (operating), or may not correspond to an AC power source having a rated voltage in the range of 220VA to 240VAC.

[0244] Referring back to FIG. 1A, the power tool 10 includes a cordless-only or DC power tool 10A set and a corded / cordless or AC / DC power tool 10B set. The DC power tool 10A set may include a low-rated voltage DC power tool 10A1 set (e.g., less than 40V such as 4V, 8V, 12V, 18V, 20V, 24V, and / or 36V), an intermediate-rated voltage DC power tool 10A2 set (e.g., 40V to 80V such as 40V, 54V, 60V, 72V, and / or 80V), and a high-rated voltage DC power tool 10A3 set (e.g., 100V to 240V such as 100V, 110V, 120V, 220V, 230V, and / or 240V). Also, the high-rated voltage DC power tools can be represented as including a subset of high-rated voltage DC power tools (e.g., 100V to 120V such as 100V, 110V, or 120V in the case of the United States, Canada, Mexico, and Japan) and a subset of extremely high-rated voltage DC power tools (e.g., 220V to 240V such as 220V, 230V, or 240V in the case of most countries in Europe, South America, Africa, and Asia). For convenience, the high-rated and extremely high-rated voltage DC power tools are collectively referred to as the high-rated voltage DC power tool 10A3 set.

[0245] The AC / DC power tool 10B generally has a rated voltage corresponding to the rated voltage of the AC commercial power supply in the countries where the tool operates or is sold (for example, in countries such as the United States, Canada, Mexico, and Japan, it is 100V, 110V, or 120V, etc., for example, 100V to 120V, and in most countries in Europe, South America, Asia, and Africa, it is 220V, 230V, and / or 240V, etc., 220V to 240V). In some examples, these high-rated voltage AC / DC power tools 10B are alternatively also referred to as AC / DC power tools having an AC rating, in which case the AC rating means the fact that the high voltage rating of the AC / DC power tool corresponds to the voltage rating of the AC commercial power supply in the country where the power tool operates and / or is sold. For the purpose of convenience, high-rated and extra-high-rated voltage AC / DC power tools are collectively referred to as the set of high-rated voltage AC / DC power tools 10B.

[0246] A. Power supply The power supply 20 set may include a DC battery pack power supply 20A set and an AC power supply 20B set. The DC battery pack power supply 20A set may include one or more of the following: a low-rated voltage battery pack 20A1 set (e.g., less than 40V such as 4V, 8V, 12V, 20V, 24V, and / or 36V, etc.), an intermediate-rated voltage battery pack 20A2 set (e.g., 40V - 80V such as 40V, 54V, 60V, 72V, and / or 80V, etc.), a high-rated voltage battery pack 20A3 set (e.g., 100V - 120V and 220V - 240V such as 100V, 110V, 120V, 220V, 230V, and / or 240V, etc.), and a variable voltage range battery pack 20A4 set (described in more detail later). The AC power supply 20B may include a power supply with a high voltage rating corresponding to the voltage ratings of the AC power supplies in the countries where the tool is operable and / or sold (e.g., in countries such as the United States, Canada, Mexico, and Japan, 100V - 120V such as 100V, 110V, or 120V, etc., and in most countries in Europe, South America, Asia, and Africa, 220V - 240V such as 220V, 230V, and / or 240V, etc.). The AC power supply may have an AC commercial power supply, or may have an alternative power supply with a similar rated voltage such as an AC generator or another portable AC power supply.

[0247] One or more of the DC battery pack power supplies 20A are configured to supply power to one or more of a set of low-rated voltage DC power tools 10A1, a set of medium-rated voltage DC power tools 10A2, and a set of high-rated voltage DC power tools 10A3, as will be described later. The AC / DC power tool 10B can be powered by one or more of the DC battery pack power supplies 20A or by one or more of the AC power supplies 20B. FIGS. 111-114 show an exemplary embodiment of an AC / DC power tool interface 22B for providing AC power from an AC power supply 20B to the AC / DC power tool 10B. The AC / DC power tool interface 22B includes a housing 23 and, at a first end, a cord 25 that includes two or three branch plugs (not shown) and, at a second end, is coupled to the housing 23. The housing 23 includes a pair 27 of DC power tool interfaces that are substantially equivalent in shape and size to the DC power tool interface 22A of the DC battery pack power supply 20A. The housing 23 also includes three branch outlets 29 (or, alternatively, two branch outlets) located between the pair 27 of DC power tool interfaces. The illustrated AC / DC power tool interface 22B of the AC power supply 20B is received within an exemplary power supply interface 16 of the AC / DC power tool shown and described in FIGS. 114 and 115. As shown in FIG. 113, the AC / DC power tool interface 22B may include a circuit 31 for receiving a "dirty" AC signal from a particular AC power source, such as a gas-powered generator. The set of battery pack chargers 30 includes one or more battery pack chargers 30 configured to charge one or more of the DC battery pack power supplies 20A. The following is a more detailed description of the power supply 20, the battery pack charger 30, and the power tool 10.

[0248] 1. DC battery pack power supply Referring to FIG. 1, as described above, the DC battery pack power source 20A includes a set of low-rated voltage battery packs 20A1, a set of intermediate-rated voltage battery packs 20A2, a set of high-rated voltage battery packs 20A3, and a set of convertible battery packs 20A4. Each battery pack may include a housing, a plurality of cells, and a power tool interface configured to couple the battery pack to a power tool or a charger. Each cell typically has a rated voltage expressed in volts (V) and a rated capacity (meaning the energy stored in the cell) expressed in ampere-hours (Ah). As is well known to those skilled in the art, when the cells in a battery pack are connected in series with each other, the voltages of the cells are additive. When the cells are connected in parallel with each other, the capacities of the cells are additive. The battery pack may include several strings of cells. Within each string, the cells may be connected in series with each other, and each string may be connected in parallel with respect to other cells. The configuration, voltage, and capacity of the cells and cell strings determine the overall rated voltage and rated capacity of the battery pack. Within each set of the DC battery pack power source 20A, there may be battery packs having the same voltage but a plurality of different rated capacities, such as, for example, 1.5 ampere-hours (Ah), 2 Ah, 3 Ah, or 4 Ah.

[0249] Figures 2A through 2C illustrate exemplary battery cell configurations of battery 24, which is part of the set of DC battery pack power supplies 20A. These examples are not intended to limit the possible cell configurations of battery 24 within each set of DC battery pack power supplies 20A. Figure 2A shows battery 24 having five battery cells 26 connected in series. In this example, if each of cells 26 has a rated voltage of 4V and a rated capacity of 1.5Ah, then this battery 24 would have a rated voltage of 20V and a rated capacity of 1.5Ah. Figure 2B shows battery 24 having ten cells. Battery 24 includes five subsets 28 of cells 26, with each subset 28 including two cells 26. The cells 26 of each subset 28 are connected in parallel, and the subsets 28 are connected in series. In this example, if each of cells 26 has a rated voltage of 4V and a rated capacity of 1.5Ah, then this battery 24 would have a rated voltage of 20V and a rated capacity of 3Ah. Figure 2C shows battery 24 having fifteen cells 120. Battery 24 includes five subsets 28 of cells 26, with each subset 28 including three cells 26. The cells 26 of each subset 28 are connected in parallel, and the subsets 28 are connected in series. In this example, if each of cells 26 has a rated voltage of 4V and a rated capacity of 1.5Ah, then this battery 24 would have a rated voltage of 20V and a rated capacity of 4.5Ah.

[0250] a. Low rated voltage battery pack Referring to FIGS. 1A and 3A, each of the low-voltage battery packs 20A1 is configured to couple to a battery pack interface 16A on a corresponding low-voltage power tool 10A1 and to a battery pack interface 16A on a corresponding low-voltage battery pack charger 30, and includes a DC power tool interface 22A. The DC power tool interface 22A may include a DC power input / output + terminal, a DC power input / output - terminal, and a communication (COMM) terminal. The set of low-voltage battery packs 20A1 may include one or more battery packs having a first rated voltage and a first rated capacity. The first rated voltage is a low rated voltage when compared to other battery packs within the DC battery pack power supply 20A, relatively speaking. For example, the low-voltage battery pack 20A1 may include a battery pack having a rated voltage of 17V to 20V (which may include a published voltage of 20V, an operating voltage of 17V to 19V, a nominal voltage of 18 volts, and a maximum voltage of 20V). However, the set of low-voltage battery packs 20A1 is not limited to a rated voltage of 20V. The set of low-voltage battery packs 20A1 may have other relatively low rated voltages such as 4V, 8V, 12V, 18V, 24V, or 36V. Within the set of low-voltage battery packs 20A1, there may be battery packs having the same rated voltage but different rated capacities. For example, the set of low-voltage battery packs 20A1 may include a 20V / 1.5Ah battery pack, a 20V / 2Ah battery pack, a 20V / 3Ah battery pack, and / or a 20V / 4Ah battery pack. When referring to the low rated voltage of the set of low-voltage battery packs 20A1, it means that the rated voltage of the set of low-voltage battery packs 20A1 is lower than the rated voltages of the set of medium-rated voltage battery packs 20A2 and the set of high-rated voltage battery packs 20A3.

[0251] Examples of battery packs within the low voltage battery pack 120A may include the DEWALT 20V MAX, a set of battery packs sold by DEWALT Industrial Tool Co. of Towson, Maryland. Other examples of battery packs that may be included within the first set of battery packs 110 are described in U.S. Patent No. 8,653,787, and U.S. Patent Application Nos. 13 / 079,158, 13 / 475,002, and 13 / 080,887, the disclosures of which are incorporated by reference.

[0252] The rated voltage of the low voltage battery pack 20A1 is generally such that the low voltage battery pack 20A1 can provide power to the low voltage DC power tool 10A1 and operate with the low voltage DC power tool 10A1, corresponding to the rated voltage of the low voltage DC power tool 10A1. Also, as will be described in more detail later, the low voltage battery pack 20A1 can be connected in series to one or more of the intermediate voltage DC power tool 10A2, the high voltage DC power tool 10A3, or the high voltage AC / DC power tool 10B, for example, such that the voltage of the low voltage battery pack 20A1 is additive and corresponds to the rated voltage of the power tool with the battery packs combined, to provide power. The low voltage battery pack 20A1 may additionally or alternatively be connected in series with one or more of the intermediate and high voltage battery packs 20A2, 20A3, or the convertible battery pack 20A4 to output a desired voltage level for any of the intermediate and high voltage DC power tools 10A2, 10A3, and / or the AC / DC power tool 10B.

[0253] b. Intermediate voltage battery pack Referring to FIGS. 1A and 3B, each of the intermediate voltage battery packs 20A2 is configured to be coupled to a battery pack interface 16A on a corresponding intermediate voltage DC power tool 10A2 and to a battery pack interface 16A on a corresponding intermediate voltage battery pack charger 30, and includes a DC power tool interface 22A. The DC power tool interface 22A may include a DC power input / output terminal, a DC power input / output terminal, and a communication (COMM) terminal. The set of intermediate voltage battery packs 20A2 may include one or more battery packs having a second rated voltage and a second rated capacity. The second rated voltage is an intermediate voltage when expressed relatively and compared to other battery packs within the set of DC battery pack power sources 20A. For example, the set of intermediate voltage battery packs 20A2 may include a battery pack having a rated voltage of 51V to 60V (which may include a published voltage of 60V, an operating voltage of 51V to 57V, a nominal voltage of 54V, and a maximum voltage of 60V). However, the set of intermediate voltage battery packs 20A2 is not limited to a rated voltage of 60V. The set of intermediate voltage battery packs 20A2 may have other relatively intermediate rated voltages such as 40V, 54V, 72V, or 80V. Within the set of intermediate voltage battery packs 20A2, there may be battery packs having the same rated voltage but different rated capacities. For example, the set of intermediate voltage battery packs 20A2 may include a 60V / 1.5Ah battery pack, a 60V / 2Ah battery pack, a 60V / 3Ah battery pack, and / or a 60V / 4Ah battery pack. When referring to the intermediate voltage of the set of intermediate voltage battery packs 20A2, it means that the rated voltage of the set of intermediate voltage battery packs 20A2 is higher than the rated voltage of the set of low voltage battery packs 20A1 but lower than the rated voltage of the set of high voltage battery packs 20A3.

[0254] The rated voltage of the intermediate rated voltage battery pack 20A2 set generally corresponds to the rated voltage of the intermediate rated voltage DC power tool 10A2 such that the intermediate rated voltage battery pack 20A2 set can supply power to the intermediate rated voltage DC power tool 10A2 and operate with the intermediate rated voltage DC power tool 10A2. Also, as will be described in more detail later, the intermediate rated voltage battery pack 20A2 set may be capable of supplying power to the high rated voltage DC power tool 10A3 or the AC / DC power tool 10B by connecting a plurality of the intermediate rated voltage battery packs 20A2 in series with each other to these tools such that, for example, the voltages of the intermediate rated voltage battery packs 20A2 are additive and correspond to the rated voltage of the power tool to which the battery packs are connected. The intermediate rated voltage battery pack 20A2 may additionally or alternatively be connected in series with any one of the low rated voltage battery pack 20A1, the high rated voltage battery pack 20A3, or the convertible battery pack 20A4 so as to output a desired voltage level for either the high rated voltage DC power tool 10A or the AC / DC power tool 10B.

[0255] c. High rated voltage battery pack Referring to FIGS. 1A and 3C, each of the high-rated voltage battery packs 20A3 is configured to couple to a battery pack interface 16A on a corresponding high-rated voltage DC power tool 10A3 and to a battery pack interface 16A on a corresponding intermediate-rated voltage battery charger 30, and includes a DC power tool interface 22A. The DC power tool interface 22A may include a DC power input / output + terminal, a DC power input / output - terminal, and a communication (COMM) terminal. The set of high-rated voltage battery packs 20A3 may include one or more battery packs having a third rated voltage and a third rated capacity. The third rated voltage is a high rated voltage when compared to other battery packs within the set of DC battery pack power supplies 220A, relatively speaking. For example, the set of high-rated voltage battery packs 20A3 may include a battery pack having a rated voltage of 102V to 120V (which may include a published voltage of 120V, an operating voltage of 102V to 114V, a nominal voltage of 108V, and a maximum voltage of 120V). However, the set of high-rated voltage battery packs 20A3 is not limited to a rated voltage of 120V. The set of high-rated voltage battery packs 20A3 may have other relatively high rated voltages such as 90V, 100V, 110V, or 120V. The high rated voltage of the set of high-rated voltage battery packs 20A3 may alternatively be referred to as an AC rated voltage, because the high rated voltage may correspond to the rated voltage of the AC commercial power supply in the country where the power tool is operable and / or sold. Within the set of high-rated voltage battery packs 20A3, there may be battery packs having the same rated voltage but different rated capacities. For example, the set of high-rated voltage battery packs 20A3 may include a 120V / 1.5Ah battery pack, a 120V / 2Ah battery pack, a 120V / 3Ah battery pack, and / or a 120V / 4Ah battery pack. When referring to the high rated voltage of the set of high-rated voltage battery packs 20A3, it means that the rated voltage of the set of high-rated voltage battery packs 20A3 is higher than the rated voltage of the set of low-rated voltage battery packs 20A1 and the rated voltage of the set of intermediate-rated voltage battery packs 20A2.

[0256] The rated voltage of the high-rated voltage battery pack 20A3 set generally corresponds to the rated voltages of the high-rated voltage DC power tool 10A3 and the AC / DC power tool 10B such that the high-rated voltage battery pack 20A3 set can supply power to the high-rated voltage DC power tool 10A3 and the AC / DC power tool 10B and can operate with the high-rated voltage DC power tool 10A3 and the AC / DC power tool 10B. Also, as will be described in more detail later, the high-rated voltage battery pack 20A3 set may be able to supply power to the extremely high-rated voltage AC / DC power tool 128 by connecting a plurality of the high-rated voltage battery packs 20A3 in series to the tool such that, for example, the voltages of the high-rated voltage battery packs 20A3 are additive. The high-rated voltage battery pack 20A3 may additionally or alternatively be coupled in series with any one of the low-rated voltage battery pack 20A1, the intermediate-rated voltage battery pack 20A2, or the convertible battery pack 20A4 to output a desired voltage level for any of the AC / DC power tools 10B.

[0257] d. Convertible battery pack Referring to FIG. 1A and as will be described in more detail later, the convertible battery pack 20A4 set is a convertible battery pack, each of which can be converted between (1) a first rated voltage and a first rated capacity and (2) a second rated voltage and a second rated capacity that are different from the first rated voltage and the first rated capacity. For example, the configuration of the cells present within the battery pack 20A4 may be changed between a first cell configuration that places the convertible battery pack 20A4 in a first battery pack configuration and a second cell configuration that places the convertible battery pack 20A4 in a second battery pack configuration. In one embodiment, in the first battery pack configuration, the convertible battery pack 20A4 has a low rated voltage and a high rated capacity, and in the second battery pack configuration, the battery pack has an intermediate rated voltage and a low rated capacity. In other words, the battery packs of the convertible battery pack 20A4 set have the ability to have at least two different rated voltages, such as a lower rated voltage and a higher rated voltage, and at least two different capacities, such as a higher rated capacity and a lower rated capacity.

[0258] As described above, low, medium, and high ratings are relative terms and are not intended to limit the battery packs of the convertible battery pack 20A4 set to a specific rating. Alternatively, the convertible battery packs of the convertible battery pack 20A4 set may be operable with the low-voltage power tool 10A1 and with the medium-voltage power tool 20A2, in which case the medium voltage is greater than the low voltage. In a particular embodiment, the convertible battery pack 20A4 has a low voltage (e.g., a published voltage of 20V, an operating voltage of 17V to 19V, a nominal voltage of 18V, and a maximum voltage of 20V, which may include 17V to 20V) corresponding to the low voltage of the low-voltage DC power tool 10A1, and an intermediate voltage (e.g., a published voltage of 60V, an operating voltage of 51V to 57V, a nominal voltage of 54V, and a maximum voltage of 60V, which may include 60V) corresponding to the intermediate voltage of the intermediate-voltage DC power tool 10A2 and is convertible therebetween. Further, as will be described later, the convertible battery pack 20A4 may be operable at its intermediate voltage and may be capable of providing power to the high-voltage DC power tool 10A3 and the high-voltage AC / DC power tool 10B when the convertible battery packs are connected in series with each other such that their voltages are additive to correspond to the rated voltage of the high-voltage DC power tool 10A3 or the AC / DC power tool 10B.

[0259] In other embodiments, the convertible battery pack may have downward compatibility with a first existing set of power tools having a first rated voltage when in the first rated voltage configuration and may have upward compatibility with a second new set of power tools having a second rated voltage. For example, the convertible battery pack may be connectable to the first set of power tools when in the first rated voltage configuration, where the first set of power tools is an existing power tool sold prior to May 18, 2014, and may be connectable to the second set of power tools when in the second rated voltage configuration, where the second set of power tools is not one sold prior to May 18, 2014. For example, in one possible embodiment, a low / intermediate rated convertible battery pack may be connectable to one or more of the DeWALT® 20V MAX cordless power tools sold by DeWALT Industrial Tool Co. of Towson, Maryland, which were sold prior to May 18, 2014, when in the 20V rated voltage configuration, and may be connectable to one or more 60V rated power tools that were not sold prior to May 18, 2014, when in the 60V rated voltage configuration. Accordingly, the convertible battery pack facilitates compatibility within a power tool system having both existing and new sets of power tools.

[0260] Referring to FIGS. 1A and 3A - 3C, the convertible battery pack 20A4 includes a plurality of cells and a DC power tool interface 22A configured to be coupled to a battery pack interface 16A on a corresponding low, medium, or high rated voltage DC power tool 10A1, 10A2, or 10A3, respectively. Also, the DC power tool interface 22A is configured to be coupled to a battery pack interface 16A on a corresponding battery pack charger 30. As will be described in more detail later, the convertible battery pack 20A4 may be coupled to one or more rated voltage battery pack chargers 30, in which case the convertible battery pack 20A4 is placed in a voltage rating configuration corresponding to the battery pack charger 30 when coupled to the battery pack charger 30. For example, the DC power tool interface 22A may include a DC power input / output + terminal, a DC power input / output - terminal, and a communication (COMM) terminal. Some possible embodiments of the convertible battery pack and its interface will be described in more detail later.

[0261] B. Battery Pack Charger Referring to FIGS. 1A and 3A - 3C, a set of battery pack chargers 30 includes one or more battery pack chargers that can be mechanically and electrically coupled to a battery pack of one or more of a low - rated voltage battery pack 20A1, an intermediate - rated voltage battery pack 20A2, a high - rated voltage battery pack 20A3, and a convertible battery pack 20A4. The set of battery pack chargers 30 can charge any of the battery packs 20A1, 20A2, 20A3, 20A4. The battery pack chargers 30 can have different rated voltages. For example, the battery pack chargers 30 may have one or more rated voltages such as a low - rated voltage, an intermediate - rated voltage, and / or a high - rated voltage to match the rated voltage of a set of battery packs in the system. Also, the battery pack chargers 30 may have a plurality of rated voltages or a range of rated voltages (e.g., low - intermediate rated voltage) so that the battery pack chargers 30 can charge battery packs having different rated voltages. Further, the battery pack charger 30 may have a battery pack interface 16A configured to couple to a DC power tool interface 22A on the battery pack. The battery pack interface 16A may include a DC power input / output + terminal, a DC power input / output - terminal, and a communication (COMM) terminal. In certain embodiments, the battery pack interface 16A may further include a converter configured to place one of the convertible battery packs in a desired rated voltage configuration to charge the battery pack, as will be described in more detail later.

[0262] C. Power Tools 1. Low - Rated Voltage DC Power Tools Referring to FIGS. 1A and 3A, a set of low-voltage power tools 10A1 includes one or more different types of cordless or DC-only power tools that utilize DC power supplied from one or more of low-voltage DC battery pack power sources 20A (such as removable and rechargeable battery packs). The rated voltage of the low-voltage DC power tool 10A1 may generally correspond to the rated voltage of the low-voltage battery pack 20A1, or may correspond to the rated voltage of the convertible battery pack 20A4 when placed in a low-voltage configuration. For example, a low-voltage DC power tool 10A1 having a rated voltage of 20V can be powered by using one or more 20V battery packs 20A1, or by a 20V / 60V convertible battery pack 20A4 in a 20V configuration. The 20V power tool rated voltage may itself be a shortened representation of a wider rated voltage, such as 17 - 20V, which can include an operating voltage range, for example, of 17V to 20V, that encompasses the rated voltage range of the low-voltage battery pack.

[0263] The low-voltage DC power tool 10A1 each includes a motor 12A that can be powered by a DC-only power source. The motor 12A can be any brushed or brushless DC electric motor, including, without limitation, a permanent magnet brushless DC motor (BLDC), a permanent magnet brushed motor, a universal motor, etc. Also, the low-voltage DC power tool 10A1 may include a motor control circuit 14A configured to receive DC power from a battery pack interface 16A via a DC line input DC+ / - and control the power supply from the DC power source to the motor 12A. In an exemplary embodiment, the motor control circuit 14A may include a power unit 18A having one or more power switches (not shown) disposed between the power source and the motor 12A. The power switch may be an electromechanical on / off switch, a power semiconductor device (e.g., a diode, FET, BJT, IGBT, etc.), or a combination thereof. In an exemplary embodiment, the motor control circuit 14A may further include a control unit 11. The control unit 11 may be configured to control the switching operation of the power switch within the power unit 18A. In an exemplary embodiment, the control unit 11 may include a microcontroller or a similar programmable module configured to control the gate of the power switch. Additionally, or alternatively, the control unit 11 may be configured to monitor and manage the operation of the DC battery pack power source 20A. Additionally, or alternatively, the control unit 11 may be configured to monitor and manage various tool operations and states such as temperature control, overspeed control, braking control, etc.

[0264] In an exemplary embodiment, as will be described in more detail below, the low-voltage DC power tool 10A1 may be a constant-speed tool (e.g., a portable light, saw, grinder, etc.). In such a power tool, the power unit 18A may simply include an electromechanical on / off switch that can be engaged by the user of the tool. Alternatively, the power unit 18A may include one or more semiconductor devices that are controlled by the control unit 11 at a fixed no-load speed to operate or stop the motor 12A of the tool.

[0265] In another embodiment, as will be described in more detail below, the low-voltage DC power tool 10A1 may be a variable-speed tool (e.g., a portable drill, impact driver, reciprocating saw, etc.). In such a power tool, the power switch of the power unit 18A may include one or more semiconductor devices (e.g., FETs and diodes, H-bridges, etc.) configured in various configurations, and the control unit 11 may control the pulse-width modulation of the power switch to control the speed of the motor 12A.

[0266] The low-voltage DC power tool 10A1 may include, among other things, portable cordless tools such as drills, circular saws, screwdrivers, reciprocating saws, vibrating tools, impact drivers, and flashlights. The low-voltage power tools may include existing cordless power tools that were sold prior to May 18, 2014. Examples of such low-voltage DC power tools 10A1 may include one or more of the cordless power tool sets DeWALT® 20V MAX sold by DeWALT Industrial Tool Co. of Towson, Maryland. The low-voltage DC power tool 10A1 may alternatively include cordless power tools that were not sold prior to May 18, 2014. In other examples, U.S. Patent Nos. 8,381,830, 8,317,350, 8,267,192, D646,947, and D644,494 disclose tools having or similar to the low-voltage cordless power tool 10A1, and these documents are incorporated by reference.

[0267] 2. Intermediate Rated Voltage DC Power Tools Referring to FIGS. 1A and 3B, the set of intermediate rated voltage DC power tools 10A2 may include one or more different types of cordless or DC-only power tools that utilize DC power supplied from one or more of the DC battery pack power supplies 20A having an intermediate rated voltage, either alone or in cooperation (such as a removable and rechargeable battery pack). The rated voltage of the intermediate rated voltage DC power tool 10A2 will generally correspond to the rated voltage of the intermediate rated voltage battery pack 20A2 or, in the case of a convertible battery pack 20A4 placed in an intermediate rated voltage configuration, the rated voltage of the convertible battery pack 20A4. For example, the intermediate rated voltage DC power tool 10A2 may have a rated voltage of 60V and may be powered by a 60V intermediate rated voltage battery pack 20A2 or a 20V / 60V convertible battery pack 20A4 in a 60V configuration. The 60V power tool rated voltage may be a shorthand for a wider rated voltage such as 17 - 20V, which may include an operating range such as 51V - 60V, including the rated voltage of the intermediate rated voltage battery pack. In an exemplary embodiment, the intermediate rated voltage DC power tool 10A2 may include a plurality of battery interfaces configured to receive two or more low rated voltage battery packs 20A1. In an exemplary embodiment, the intermediate rated voltage DC power tool 10A2 may also include, in addition, a circuit for coupling the DC battery pack power supplies 20A in series to generate a desired intermediate rated voltage corresponding to the rated voltage of the intermediate rated voltage DC power tool 10A2.

[0268] Similar to the above-mentioned low-rated voltage DC power tool 10A1, the medium-rated voltage DC power tool 10A2 each includes a motor 12A that can be powered by a DC battery pack power supply 20A. The motor 12A can be any brushed or brushless DC electric motor, including, without limitation, a permanent magnet brushless DC motor (BLDC), a permanent magnet brushed motor, a universal motor, etc. Also, the medium-rated voltage DC power tool 10A2 includes a motor control circuit 14A configured to receive DC power from a battery pack interface 16A via a DC line input DC+ / - and control the power supply from the DC power supply to the motor 12A. In an exemplary embodiment, the motor control circuit 14A may include a power unit 18A having one or more power switches (not shown) disposed between the power supply and the motor 12A. The power switch may be an electromechanical on / off switch, a power semiconductor device (e.g., a diode, FET, BJT, IGBT, etc.), or a combination thereof. In an exemplary embodiment, the motor control circuit 14A may further include a control unit 11. The control unit 11 may be configured to control the switching operation of the power switch within the power unit 18A. Similar to the above-mentioned motor control circuit 14A for the low-rated voltage DC power tool 10A1, the motor control circuit 14A can control the motor 12A at a fixed or variable speed. In an exemplary embodiment, the control unit 11 may include a microcontroller or a similar programmable module configured to control the gate of the power switch. Additionally, or alternatively, the control unit 11 may be configured to monitor and manage the operation of the DC battery pack power supply 20A. Additionally, or alternatively, the control unit 11 may be configured to monitor and manage various tool operations and states such as temperature control, overspeed control, braking control, etc.

[0269] The intermediate voltage DC power tool 10A2 can include tools of a type similar to the low voltage DC power tool 10A1 that have relatively high power output requirements, such as drills, circular saws, screwdrivers, reciprocating saws, vibrating tools, impact drivers, and flashlights. Also, the intermediate voltage DC power tool 10A2 can additionally or alternatively have other types of tools that require more power or capacity than the low voltage DC power tool 10A1, such as chain saws, string trimmers, hedge trimmers, lawn mowers, nail guns, and / or rotary hammers.

[0270] In yet another and / or further embodiment, as will be described in more detail hereinafter, the motor control circuit 14A of the intermediate voltage DC power tool 10A2 enables power supply to the motor 12A using a plurality of DC battery pack power supplies 20A that have different rated voltages and are less than the intermediate voltage. In other words, the intermediate voltage DC power tool 10A2 may be configured to operate at a plurality of rated voltages (e.g., at a low voltage or at an intermediate voltage). Such an intermediate voltage DC power tool 10A2 can be described as having a plurality of voltage ratings corresponding to each of the voltage ratings of the plurality of DC power supplies capable of powering the tool. For example, the intermediate voltage DC power tool 10A2 of FIG. 3B can have a low / intermediate voltage (e.g., 20V / 60V rated voltage, 40V / 60V rated voltage) with the ability to be selectively powered by one of the low voltage battery packs 20A1 (e.g., a 20V battery pack), by one of the intermediate voltage battery packs 20A2 (e.g., a 60V battery pack), or by a convertible battery pack 20A4 in a low voltage configuration or an intermediate voltage configuration. In an alternative embodiment, the intermediate voltage DC power tool 10A2 can operate by using a pair of low voltage battery packs 20A1 connected in series (e.g., two 18V battery packs 20A1 connected in series to generate a combined low voltage of 36V) to operate at yet another different low or intermediate voltage that is different from the intermediate voltage of the motor 12A within the intermediate voltage DC power tool 10A2.

[0271] Operation of the power tool motor 12A at significantly different voltage levels will result in a large difference in the performance of the power tool, particularly in the rotational speed of the motor, which can be significant and, in some cases, unsatisfactory to the user. Thus, in one embodiment of the invention described herein, the motor control circuit 14A is configured to optimize the performance of the motor 12A based on the rated voltage of the power supply, i.e., based on whether the intermediate rated voltage DC power tool 10A2 is coupled to either a low rated voltage DC power supply (e.g., a low rated voltage battery pack 20A1) or an intermediate rated voltage power supply (e.g., an intermediate rated voltage battery pack 20A2 in which the motor 212A in the intermediate rated voltage DC power tool 10A2 is optimized or rated). By doing so, the difference in the output performance of the tool is minimized or at least reduced to a level satisfactory to the end user.

[0272] In this embodiment, the motor control circuit 14A is configured to increase or decrease the effective motor performance from the power supply to a level corresponding to the operating voltage range (or voltage rating) of the intermediate rated voltage DC power tool 10A2. Specifically, when used with the intermediate rated voltage battery pack 20A2, the motor control circuit 14A can reduce the power output of the tool 10A in a manner satisfactory to the end user so as to match (or be reasonably close to) the output level of the tool 10A when used with the low rated voltage battery pack 20A1. Alternatively, or additionally, when used with the low rated voltage battery pack 20A1, the motor control circuit 14A can increase the power output of the intermediate rated voltage DC power tool 10A2 in a manner satisfactory to the end user so as to match (or be reasonably close to) the output level of the intermediate rated voltage DC power tool 10A2 when used with the intermediate rated voltage battery pack 20A2. In one embodiment, the low / intermediate rated voltage DC power tool 10A2 may be configured to identify the rated voltage of the power supply via, for example, a battery ID and optimize the motor performance accordingly. These methods for optimizing (i.e., increasing or decreasing) the effective motor performance will be described in detail later in the present disclosure.

[0273] 3. High Rated Voltage DC Power Tool Referring to FIGS. 1A and 3C, the high voltage DC power tool 10A3 set may include a cordless (DC only) high voltage (or AC rated) power tool having a motor configured to operate at high voltage and high output power (e.g., such as about 1000 to 1500 watts). Similar to the low and intermediate voltage DC power tools 10A1, 10A2, the high voltage DC power tool 10A3 may also include various cordless tools (i.e., power tools, outdoor tools, etc.) for high power output applications. The high voltage DC power tool 10A3 may include tools of a type similar to low voltage and intermediate voltage DC power tools such as, for example, drills, circular saws, screwdrivers, reciprocating saws, vibrating tools, impact drivers, flashlights, string trimmers, hedge trimmers, lawn mowers, nailers, and / or rotary hammers. The high voltage DC power tool may additionally or alternatively include other types of tools that require higher power or capacity such as, for example, mitre saws, chain saws, hammer drills, grinders, and compressors.

[0274] Similar to the low and medium rated voltage DC power tools 10A1 and 10A2, the high rated voltage DC power tool 10A3 is configured to enable operation from one or more DC battery pack power sources 20A having a high rated voltage corresponding to the rated voltage of the power tool 10A, and includes a motor 12A, a motor control circuit 14A, and a battery pack interface 16A. Similar to the motor 12A described above with reference to FIG. 3A, the motor 12A may be any brushed or brushless DC electric motor, including, without limitation, a permanent magnet brushless DC motor (BLDC), a permanent magnet DC brushed motor (PMDC), a universal motor, and the like. Similarly, the motor control circuit 14A may include a power unit 18A having one or more power switches (not shown) disposed between the power source and the motor 12A. The power switch may be an electromechanical on / off switch, a power semiconductor device (e.g., a diode, FET, BJT, IGBT, etc.), or a combination thereof. In one embodiment, the motor control circuit 14A may further include a control unit 11. The control unit 11 may be configured to control the switching operation of the power switches within the power unit 18A. The motor control circuit 14A may control the motor 12A at a fixed or variable speed. In one embodiment, the control unit 11 may include a microcontroller or a similar programmable module configured to control the gates of the power switches. Additionally, or alternatively, the control unit 11 may be configured to monitor and manage the operation of the DC battery pack power source 20A. Additionally, or alternatively, the control unit 11 may be configured to monitor and manage the operation and status of various tools.

[0275] Referring to FIG. 3C, the high-rated voltage DC power tool 10A3 may be powered by a single DC battery pack power source 20A received within a battery pack interface (or, battery receptacle) 16A. In one embodiment, the DC battery pack power source 20A may be a high-rated voltage battery pack 20A3 having a high-rated voltage (e.g., 120V) corresponding to the rated voltage of the high-rated voltage DC power tool 10A3.

[0276] Referring to FIG. 3C, in an alternative embodiment, the battery pack interface 16A of the high rated voltage DC power tool 10A3 may include two or more battery outlets 16A1, 16A2 that receive two or more DC battery pack power supplies 20A at a given time. In one embodiment, the high rated voltage DC power tool 10A3 may be powered by a pair of DC battery pack power supplies 20A that are received together within the battery outlets 216A1, 216A2. Also, in this embodiment, the battery pack interface 16A may include a switching unit (not shown) configured to connect two DC battery pack power supplies 20A in series. The switching unit may include, for example, a circuit provided within the battery pack interface 16A or within the motor control circuit 14A. Alternatively, the DC battery pack power supply 20A may be an intermediate rated voltage battery pack 20A2 (e.g., two 60V battery packs connected in series for a combined rated voltage of 120V) connected in series via a switching unit 120-10 to output a similar high rated voltage. In yet another embodiment, a single high rated voltage battery pack 20A3 may be coupled to one of the battery outlets to provide a rated voltage of 120V. For example, the high rated voltage DC power tool 10A2 may have a rated voltage of 60V and may be powered by two 60V intermediate rated voltage battery packs 20A2 or by two 20V / 60V convertible battery packs 20A4 in its 60V configuration. The 120V power tool rated voltage may itself be a shortened representation of a wider rated voltage range of 102V to 120V, which may include, for example, an operating range of 102V to 120V that encompasses the operating ranges of the two intermediate rated voltage battery packs.

[0277] In one embodiment, the total rated voltage of the battery packs received within one or more cordless power tool battery outlets 16A may correspond to the rated voltage of the cordless DC power tool 10A itself. However, in other embodiments, the high-rated voltage cordless DC power tool 10A3 may, in addition to this, be operable using one or more DC battery pack power sources 20A that cooperatively have a rated voltage less than the rated voltages of the motor 12A and the motor control circuit 14A within the high-rated voltage cordless DC power tool 10A3. In this latter case, the cordless DC power tool 10A may be described as having multiple rated voltages corresponding to the rated voltage of the DC battery pack power source 20A that the high-rated voltage DC power tool 10A3 will receive. For example, the high-rated voltage DC power tool 10A3 may be an intermediate / high-rated voltage DC power tool (e.g., 60V / 120V, 60 - 120V power tool, 80V / 120V, or 80 - 120V power tool) if it is operable using a high-rated voltage battery pack 20A3 or an intermediate-rated voltage battery pack 20A2 that has the ability to be selectively powered by a plurality of low-rated voltage battery packs 20A1 (e.g., 20V battery packs), one or more intermediate-rated voltage battery packs 20A2 (e.g., 60V battery packs), one high-rated voltage battery pack 20A3, or one or more convertible battery packs 20A4. The user may mix and match any of the DC battery pack power sources 20A for use with the high-rated voltage DC power tool 10A3.

[0278] The motor (which can be optimized to function at high power and high voltage ratings as described) within the high-rated voltage power tool 10A3 may be configured to optimize motor performance based on the rated voltage of the low-rated voltage DC battery pack 20A1 so as to operate acceptably with a DC power supply having a total voltage rating that is less than the voltage rating of the motor. As briefly described above and as will be described in detail in the present disclosure, this can be accomplished by optimizing (i.e., increasing or decreasing) the effective motor performance from the power supply to a level corresponding to the operating voltage range (or voltage rating) of the high-rated voltage DC power tool 10A3.

[0279] In an alternative or additional embodiment (not shown), an AC / DC adapter may be provided to couple an AC power supply to the battery pack interface 16 and convert the AC power from the AC power supply to a DC signal of equivalent rated voltage for supply to the high-rated voltage DC power tool 10A3 via the battery pack interface 16A.

[0280] 4. High (AC) Rated Voltage AC / DC Power Tool Referring to FIGS. 1A and 4, the corded / cordless (AC / DC) power tool 10B has an AC / DC power interface 16 having a DC line input DC+ / -(16A), an AC line input ACH, ACL (16B), and a communication line (COMM), respectively, coupled to a motor control circuit 14B. The AC / DC power interface 16 is configured to be coupled to a tool interface of one or more of a DC battery pack power source 20A and an AC power source 20B. The DC battery pack power source 20A may have a DC power input / output + terminal, a DC power input / output - terminal, and a communication (COMM) terminal that can be coupled to the DC+ / - line input and the communication line (COMM) in the AC / DC power interface 16 within the AC / DC power tool 10B. Also, the DC power input / output + terminal, the DC power input / output - terminal, and the communication (COMM) terminal of the DC battery pack power source 20A may be coupled to the battery pack interface 16A of the battery pack charger 30 for the DC battery pack power source 20A as described above. The AC power source 20B may be coupled to the ACH, ACL, and / or communication (COMM) terminals of the power interface 16B within the AC / DC power tool 10B by AC power H and AC power L terminals or lines, as well as by a communication (COMM) terminal or line. In each AC / DC power tool 10B, the motor control circuit 14B and the motor 12B are designed to optimize the performance of the motor for a given rated voltage of the power tool and the power source.

[0281] As will be described further below, the motor 12B may be a brushless or brushed motor such as a permanent magnet brushless DC motor (BLDC), a permanent magnet DC motor with brushes (PMDC), or a universal motor. The motor control circuit 14B may, as will be described in more detail below, enable constant speed operation or variable speed operation and may include different power switching and control circuits depending on the type of motor and speed control.

[0282] In an exemplary embodiment, the AC / DC power interface 16 may be configured to include a single battery pack interface (e.g., a battery pack receptacle) 16A and an AC power interface 16B (e.g., an AC power cable received within the tool housing). The motor control circuit 14B in this embodiment may be configured to selectively switch between an AC power source 20B and a DC battery pack power source 20A. In this embodiment, the DC battery pack power source 20A may be a high-rated voltage battery pack 20A3 having a high-rated voltage (e.g., 120V) corresponding to the rated voltage of the AC / DC power tool 10B and / or the rated voltage of the AC power source 20B. The motor control unit 14B may be configured to supply AC power from the AC power source 20B in a standard setting when detecting current from the AC power source 20B, and otherwise to supply power from the DC battery pack power source 20A.

[0283] Referring to FIGS. 114-117, in another exemplary embodiment, the AC / DC power interface 16 may be configured to include, in addition to the AC power interface 16B, a pair of battery interfaces 16A such as two battery receptacles 16A1, 16A2. This configuration allows the AC / DC power tool 10B to be powered by a plurality of DC battery pack power sources 20A that cooperatively have a high-rated voltage corresponding to the AC rated voltage of the commercial power supply when connected in series. In this embodiment, the AC / DC power tool 10B may be powered by a pair of DC battery pack power sources 20A received within the battery receptacles 16A1, 16A2. In one embodiment, a switching unit may be provided and configured to connect two DC battery pack power sources 20A in series. Such a switching unit may include, for example, a simple wire connection provided within the AC / DC power interface 16 that connects the battery receptacles 16A1, 16A2. Alternatively, such a switching unit may be provided as a pair of motor control circuits 14B.

[0284] In this embodiment, the DC battery pack power supply 20A may be two of the intermediate rated voltage battery packs 20A2 connected in series via a switching unit (for example, two 60V battery packs connected in series for a combined rated voltage of 120V) so as to output the same high rated voltage. Referring to FIG. 116, in yet another exemplary embodiment, a single high rated voltage voltage pack 20A3 may be coupled to one of the battery outlets 16A2 to provide a rated voltage of 120V, and the other battery outlet 16A1 may be left in an unused state. In this embodiment, the motor control circuit 14B may be configured to select one of the AC power supply 20B or the combined DC battery pack power supply 20A to provide power to the motor 12B.

[0285] In these embodiments, the total rated voltage of the DC battery pack power supply 20A received within one or more AC / DC power tool battery pack outlets 16A may correspond to the rated voltage level of the AC / DC power tool 10B, which generally corresponds to the rated voltage of the AC commercial power supply 20B. As described above, the power supply 20 used for the high-rated voltage DC power tool 10A3 or the AC / DC power tool 10B is the high-rated voltage commercial AC power supply 20B. For example, the AC / DC power tool 10A2 may have a rated voltage of 120V and may be powered by a 120VAC AC commercial power supply or by two 20V / 60V convertible battery packs 20A4 in series connection in its 60V configuration. The 120V power tool rated voltage may be a shortened representation of a wider rated voltage, such as 100V - 120V, which encompasses the operating range of the power tool and the operating range of the two intermediate rated voltage battery packs. In one embodiment, the 120V power tool rated voltage may be a still wider operating range of 90V - 132V, which encompasses the entire operating range of the two intermediate rated voltage battery packs (e.g., 102VDC - 120VDC), and may be a shortened representation of all available AC power supplies (e.g., 100VAC, 110VAC, 120VAC) in North America and Japan with a ±10% error factor to account for voltage fluctuations in the AC commercial power supply.

[0286] In other embodiments, in addition to this, the AC / DC power tool 10B may be operable using one or more of the DC battery pack power supplies 20A that have a rated voltage that is less than the AC rated voltage of the AC commercial power supply and less than the voltage ratings of the motor 12A and the motor control circuit 14A. In this embodiment, the AC / DC power tool 10B may be expressed as having a plurality of rated voltages corresponding to the rated voltages of the DC battery pack power supply 20A and the AC power supply 20B that the AC / DC power tool 10B is to receive. For example, the AC / DC power tool 10B is an intermediate / high rated power tool if it is operable using an intermediate rated voltage battery pack 20A2 or a high rated voltage AC power supply 20B (e.g., 60V / 120V or 60~120V or 60VDC / 120VDC). According to this embodiment, the user may be given the ability to mix and match any of the DC battery pack power supplies 20A for use with the AC / DC power tool 10B. For example, the AC / DC power tool 10B may be usable with two low rated voltage packs 20A1 (e.g., 20V, 30V, or 40V packs) connected in series via a switching unit to output a rated voltage of 40V to 80V. In another example, the AC / DC power tool 10B may be used with a low rated voltage battery pack 20A1 and an intermediate rated voltage battery pack 20A2 for a total rated voltage of 80V to 100V.

[0287] For the motor 12B in the AC / DC power tool 10B (optimized to operate at high output power and high voltage ratings as described above) to function acceptably with a DC battery pack power supply having a total voltage rating less than the high voltage rating of the tool (e.g., within the range of 40V to 100V as described above), the motor control circuit 14B may be configured to optimize the motor performance based on the rated voltage of the DC battery pack power supply 20A. As briefly described above and as will be described in detail later in the present disclosure, this may be performed by optimizing (i.e., increasing or decreasing) the effective motor performance from the power supply to a level corresponding to the operating voltage range (or voltage rating) of the high rated voltage DC power tool 10A3.

[0288] II. AC / DC Power Tools and Motor Control Referring to FIGS. 1A and 5A, the high-rated voltage AC / DC power tool 10B can be classified based on the type of motor, i.e., the high-rated voltage AC / DC power tool 122 having a brushed motor and the high-rated voltage AC / DC power tool 128 having a brushless motor. Also, referring to FIG. 5B, the AC-rated voltage AC / DC power tool 122 having a brushed motor can be further classified into four subsets: a constant-speed AC / DC power tool 123 having a universal motor, a variable-speed AC / DC power tool 124 having a universal motor, a constant-speed AC / DC power tool 125 having a DC brushed motor, and a variable-speed AC / DC power tool 126 having a universal motor, based on speed control and motor type. These various sets and subsets of high-rated voltage AC / DC power tools will be described in more detail later.

[0289] In the following FIGS. 5A - 15E, the power tools 123, 124, 125, 126, and 128 can each correspond to the power tool 10B shown in FIG. 4. Similarly, in the following FIGS. 5A - 15E, the motors 123-2, 124-2, 125-2, 126-2, and 202 can each correspond to the motor 12B in FIG. 4, the motor control circuits 123-4, 124-4, 125-4, 126-4, and 204 can each correspond to the motor control circuit 14B in FIG. 4, the power units 123-6, 124-6, 125-6, 126-6, and 206 can each correspond to the power unit 18B in FIG. 4, the control units 123-8, 124-8, 125-8, 126-8, and 208 can each correspond to the control unit 11B in FIG. 4, and the power interfaces 123-5, 124-5, 125-5, 126-5, and 128-5 can each correspond to the power interface 16B in FIG. 4.

[0290] A. Constant-Speed AC / DC Power Tool with a Universal Motor Next, referring to FIGS. 6A - 6D, a first subset of the AC / DC power tools 122 having a brush motor includes a constant - speed AC / DC power tool 123 having a universal motor (hereinafter referred to as the constant - speed universal motor tool 123). These include corded / cordless (AC / DC) power tools that operate at a constant speed under no - load (or a certain load), and include a brushed universal motor 123 - 2 configured to operate at a high rated voltage (e.g., 100V - 120V, or more broadly 90V - 132V) and high power (e.g., 1500 - 2500 watts). The universal motor is a series - wound motor having a stator field coil and a commutator connected in series to the field coil. The universal motor in this system can operate not only with a DC power source but also with an AC power source. In one embodiment, the constant - speed universal motor tool 123 may include high - power tools for high - power applications such as a concrete hammer, a mitre saw, a table saw, a vacuum cleaner, a blower, and a lawn mower.

[0291] In one embodiment, the constant - speed universal motor tool 123 includes a motor control circuit 123 - 4 that operates the universal motor 123 - 2 at a constant speed in a no - load state. The power tool 123 further includes a power interface 123 - 5 configured to receive power from one or more of the above - mentioned DC power source and / or AC power source. The power interface 123 - 5 is electrically coupled to the motor control circuit 123 - 4 by DC power lines DC+ and DC - (for supplying power from the DC power source) and by AC power lines ACH and ACL (for supplying power from the AC power source).

[0292] In one embodiment, the motor control circuit 123-4 may include a power unit 123-6. In one embodiment, the power unit 123-6 includes an electromechanical on / off switch 123-12. In one embodiment, the tool 123 includes an on / off trigger or actuator (not shown) coupled to the on / off switch 123-12 that enables a user to activate or deactivate the motor 123-2. The on / off switch 123-12 is provided in series with the power supply to electrically connect or disconnect the supply of power from the power interface 123-5 to the motor 123-2.

[0293] Referring to FIG. 6A, a constant speed universal motor tool 123 is shown according to one embodiment, where the ACH and DC+ power lines are coupled together at a common positive node 123-11a, and the ACL and DC- power lines are coupled together at a common negative node 123-11b. In this embodiment, the on / off switch 123-12 is disposed between the positive common node 123-11a and the motor 123-2. In one embodiment, a mechanical lockout device may be utilized to ensure that only one of the AC or DC power supplies is utilized at any given point in time. In an exemplary embodiment, the mechanical lockout device may physically block access to one of the AC or DC power supplies at any given point in time.

[0294] In addition to this, as shown in FIG. 6A, a constant speed universal motor tool 123 may further be provided with a control unit 123-8. In one embodiment, the control unit 123-8 may be coupled to a power switch 123-13 disposed between the DC+ power line of the power interface 123-5 and the on / off switch 123-12 within the power unit 123-6. In one embodiment, the control unit 123-8 may be provided to monitor the state of the power tool 123 and / or the battery. In one embodiment, the control unit 123-8 may be coupled to an element of the tool 123 such as a thermistor within the tool. Also, in one embodiment, the control unit 123-8 may be coupled to one or more battery packs via a communication signal line COMM provided from the power interface 123-5. The COMM signal line may provide control or information signals related to the operation or state of the one or more battery packs to the control unit 123-8. In one embodiment, the control unit 123-8 may be configured to interrupt power from the DC+ power line from the power interface 123-5 using the power switch 123-13 when a fault condition of the tool (e.g., tool temperature overrun, tool current overrun, etc.) or a fault condition of the battery (e.g., battery temperature overrun, battery current overrun, battery voltage overrun, battery voltage underrun, etc.) is detected. In one embodiment, the power switch 123-13 may include a FET or other controllable switch controlled by the control unit 123-8.

[0295] FIGS. 6B to 6D show a constant speed universal motor tool 123 according to an alternative embodiment, in which case the DC power lines DC+ / DC- and the AC power lines ACH / ACL are isolated via a power switching unit 123-15 to ensure that power cannot be supplied simultaneously from both the AC and DC power sources (even when the power interface 123-5 is coupled to both AC and DC power sources).

[0296] In one embodiment, as shown in FIG. 6B, the power switching unit 123-15 may include a normally closed single-pole single-throw relay disposed between the DC power line DC+ and the on / off switch 123-12 with the coil coupled to the AC power lines ACH and ACL. The output of the power switching unit 123-15 and the ACH power line are coupled together to the power switch 123-13. When no AC power is supplied, the relay is inactive and the DC power line DC+ is coupled to the power switch 123-13. When AC power is supplied, the coil is energized and the relay becomes active, and thus the DC power line DC+ is separated from the power switch 123-13.

[0297] In an alternative or additional embodiment, as shown in FIG. 6C, the power switching unit 123-15 may include a double-pole double-throw switch 123-16 having an input terminal coupled to the DC+ and ACH power lines of the power interface 123-5 and an output terminal coupled together to the power switch 123-13. In one embodiment, a second double-pole double-throw switch 123-17 is provided having an input terminal coupled to the negative DC- and ACL power lines of the power interface 123-5 and an output terminal coupled together to the negative terminal of the motor 123-2. In one embodiment, switches 123-16 and 123-17 may be controlled via a relay coil as in FIG. 6B. Alternatively, switches 123-16 and 123-17 may be controlled via a mechanical switching mechanism (e.g., a movable contact provided on a battery connector that closes the switch when a battery pack is inserted into the battery connector).

[0298] In another embodiment, as shown in FIG. 6D, the power switching unit 123-15 may include a single-pole double-throw switch 123-18 having an input terminal coupled to the DC+ and ACH power lines of the power interface 123-5 and an output terminal coupled to the power switch 123-13. In one embodiment, a second single-pole double-throw switch 123-19 is provided having an input terminal coupled to the negative DC- and ACL power lines of the power interface 123-5 and an output terminal coupled to the negative terminal of the motor 123-2. In one embodiment, switches 123-18 and 123-19 may be controlled via a relay coil, similar to FIG. 6B. Alternatively, switches 123-18 and 123-19 may be controlled via a mechanical switching mechanism (e.g., a movable contact provided on a battery socket that closes the switch when the battery pack is inserted into the battery socket).

[0299] The tool 123 of FIGS. 6A-6D is provided with a control unit 123-8 and a power switch 123-13 to interrupt power supply in the event of a tool or battery fault condition, but it should be understood that the tool 123 may be provided without the control unit 123-8 and the power switch 123-13. For example, one or more battery packs may be provided with their own controller to monitor their fault condition and manage their operation.

[0300] 1. Constant speed universal motor tool having a power source with equivalent voltage rating In FIGS. 6A-6D above, the power tool 123 is designed to operate, for example, in a high rated voltage range of 100V to 120V (corresponding to the AC power voltage range of 100VAC to 120VAC in North America and Japan), or more broadly, in the range of 90V to 132V (±10% of the 100-120V AC power voltage range), and at high power (e.g., 1500 to 2500 watts). Specifically, the components of the motor 123-2 and the power unit 123-6 of the power tool 123 are designed and optimized to handle a high rated voltage of 100 to 120V, or more broadly, 90V to 132V. This can be accomplished by selecting a voltage-compatible electric device and designing a motor with an appropriate size and winding configuration to handle the high rated voltage range. Also, the motor 123-2 has an operating voltage or operating voltage range that can be equivalent to, included in, or corresponding to the operating voltage or operating voltage range of the tool 123.

[0301] In one embodiment, the power interface 123-5 is configured to provide an AC power line having a nominal voltage within the range of 100 to 120V (e.g., 120VAC at 50-60Hz in the United States or 100VAC in Japan) from an AC power source, or to provide a DC power line having a nominal voltage within the range of 100 to 120V (e.g., 108VDC) from a DC power source. In other words, both the DC nominal voltage and the AC nominal voltage provided through the power interface 123-5 correspond to (e.g., match, overlap, or are included in) the operating voltage range of the motor 123-2 (i.e., the high rated voltage of 100V to 120V, or more broadly, approximately 90V to 132V). Note that the nominal voltage of 120VAC corresponds to an average voltage of approximately 108V when measured in the positive half cycle of the AC sine wave, which provides equivalent speed performance to 108VAC power.

[0302] 2. Constant-Speed Universal Motor Tool with Power Sources Having Different Voltage Ratings FIG. 6E shows a power tool 123 according to another embodiment of the present invention, where the power supply provided by an AC power source has a nominal voltage that is significantly different from the nominal voltage provided by a DC power source. For example, the AC power line of the power supply interface 123-5 may provide a nominal voltage within the range of 100 - 120V, and the DC power line may provide a nominal voltage within the range of 60V - 100V (e.g., 72VDC or 90VDC). In another example, the AC power line may provide a nominal voltage within the range of 220 - 240V (e.g., 230V in many European countries or 220V in many African countries), and the DC power line may provide a nominal voltage within the range of 100 - 120V (e.g., 108VDC).

[0303] Operation of the power tool motor 123-2 at significantly different voltage levels can result in a large difference in the performance of the power tool, particularly in the rotational speed of the motor, which can be significant and, in some cases, unsatisfactory for the user. Also, supplying a voltage level outside the operating voltage level of the motor 123-2 can damage the motor and related switching components. Thus, in one embodiment of the present invention described herein, the motor control circuit 123-4 is configured to optimize the power supply to the motor 123-2 (and thus motor performance) according to the nominal voltage of the AC or DC power line such that the motor 123-2 provides substantially uniform speed and power performance in a manner satisfactory to the end user, regardless of the nominal voltage provided on the AC or DC power line.

[0304] In this embodiment, the motor 123-2 may be designed and configured to operate in a voltage range that includes the nominal voltage of the DC power line. In an exemplary embodiment, the power tool 123 may operate in a voltage range of 60V to 90V (or, more broadly, 54V to 99V, which is ±10% of this), which includes the nominal voltage of the DC power line of the power interface 123-5 (e.g., 72VDC or 90VDC), but is less than the nominal voltage of the AC power line (e.g., 220V to 240V). In another exemplary embodiment, the motor 123-2 may be designed to operate in a voltage range of 100V to 120V (or, more broadly, 90V to 132V, which is ±10% of this), which includes the nominal voltage of the DC power line of the power interface 123-5 (e.g., 108VDC), but is less than the nominal voltage range of 220 to 240V of the AC power line.

[0305] In one embodiment, in order for the tool 123 to operate with a higher nominal voltage of the AC power line, the tool 123 is further provided with a phase-controlled AC switch 123-16. In one embodiment, the AC switch 123-16 may include a triac or SRC switch controlled by the control unit 123-8. In one embodiment, the control unit 123-8 may be configured to set a fixed conduction band (or firing angle) of the AC switch 123-16 corresponding to the operating voltage of the tool 123.

[0306] For example, in the case of a tool 123 having a motor 123-2 with an operating voltage range of 60V to 100V, but receiving AC power with a nominal voltage of 100V to 120V, the conduction band of the AC switch 123-16 may be set to a value within the range of 100 to 140 degrees, such as, for example, about 120 degrees. In this example, the arcing angle of the AC switch 123-16 may be set to 60 degrees. By setting the arcing angle to about 60 degrees, the AC voltage supplied to the motor is approximately within the range of 70 to 90V, which corresponds to the operating voltage of the tool 123. In this way, the control unit 123-8 optimizes the power supply to the motor 123-2.

[0307] In another example, in the case of a tool 123 having a motor 123-2 with an operating voltage range of 100 to 120V, but receiving AC power with a nominal voltage of 220 to 240V, the conduction band of the AC switch 123-16 may be set to a value within the range of 70 to 110 degrees, such as, for example, about 90 degrees. In this example, the arcing angle of the AC switch 123-16 may be set to 90 degrees. By setting the arcing angle to 90 degrees, the AC voltage supplied to the motor is approximately within the range of 100 to 120V, which corresponds to the operating voltage of the tool 123.

[0308] In this way, the motor control circuit 123-4 optimizes the power supply to the motor 123-2 according to the nominal voltage of the AC or DC power line so that the motor 123-2 provides substantially uniform speed and power performance in a manner satisfactory to the end user, regardless of the nominal voltage provided on the AC or DC power line.

[0309] B. Variable Speed AC / DC Power Tools with Universal Motors Next, referring to FIGS. 7A - 7H, a second subset of AC / DC power tools having a brush motor 122 includes a variable speed AC / DC power tool 124 having a universal motor (herein also referred to as the variable speed universal motor tool 124). These include corded / cordless (AC / DC) power tools that operate at variable speeds in a no-load state and are configured to operate at high rated voltages (e.g., 100V - 120V, more broadly 90V - 132V) and at high power (e.g., 1500 - 2500 watts), and include a brushed universal motor 124-2. As described above, the universal motor is a series-wound motor having a stator field coil and a commutator connected in series with the field coil. The universal motor in this scheme can operate not only with a DC power source but also with an AC power source. In one embodiment, the variable speed universal motor tool 124 can include high-power tools having variable speed control, such as a concrete drill, a hammer, a grinder, a saw, etc.

[0310] In one embodiment, the variable speed universal motor tool 124 is provided with a variable speed actuator (not shown), such as, for example, a trigger switch, a contact detection switch, a capacitive switch, a gyroscope, or other variable speed input mechanism (not shown) that can be engaged by the user. In one embodiment, the variable speed actuator is coupled to or includes a potentiometer or other circuit for generating a variable speed signal (e.g., a variable voltage signal, a variable current signal, etc.) indicating the desired speed of the motor 124-2. In one embodiment, the variable speed universal motor tool 124 may additionally be provided with an on / off trigger or actuator (not shown) that enables the user to start the motor 124-2. Alternatively, the on / off trigger function may be incorporated into the variable speed actuator such that an initial actuation of the variable speed trigger by the user functions to start the motor 124-2 (i.e., there is no separate on / off actuator).

[0311] In one embodiment, the variable speed universal motor tool 124 includes a motor control circuit 124-4 that operates the universal motor 124-2 at a variable speed in a no-load or constant load state. The power tool 124 further includes a power interface 124-5 configured to receive power from one or more of the DC power source and / or AC power source described above. The power interface 124-5 is electrically coupled to the motor control circuit 124-4 by DC power lines DC+ and DC- (for supplying power from the DC power source) and by AC power lines ACH and ACL (for supplying power from the AC power source).

[0312] In one embodiment, the motor control circuit 124-4 may include a power unit 124-6. In one embodiment, the power unit 124-6 may include a DC switch circuit 124-14 disposed between the DC power lines DC+ / DC- and the motor 124-2, and an AC switch 124-16 disposed between the AC power lines ACH / ACL and the motor 124-2. In one embodiment, the DC switch circuit 124-14 may include a combination of one or more power semiconductor devices (e.g., diodes, FETs, BJTs, IGBTs, etc.) configured to provide power from the DC power lines DC+ / DC- to the motor 124-2 in a switchable manner. In one embodiment, the AC switch 124-16 may include a phase-controlled AC switch (e.g., triac, SCR, thyristor, etc.) configured to provide power from the AC power lines ACH / ACL to the motor 124-2 in a switchable manner.

[0313] In one embodiment, the motor control circuit 124-4 may further include a control unit 124-8. The control unit 124-8 may be configured to control the switching operations of the DC switch circuit 124-14 and the AC switch 124-16. In one embodiment, the control unit 124-8 may include a microcontroller or a similar programmable module configured to control the gates of the power switches. In one embodiment, when power is supplied from one or more battery packs through the DC power lines DC+ / DC-, the control unit 124-8 is configured to control the PWM duty cycle of one or more semiconductor switches in the DC switch circuit 124-14 so as to control the speed of the motor 124-2 based on the speed signal from the variable speed actuator. Similarly, when power is supplied from an AC power source through the AC power lines ACH / ACL, the control unit 124-8 is configured to control the arc angle (or conduction angle) of the AC switch 124-16 so as to control the speed of the motor 124-2 based on the speed signal from the variable speed actuator.

[0314] Also, in one embodiment, the control unit 124-8 may be coupled to one or more battery packs via a communication signal line COMM provided from the power interface 124-5. The COMM signal line may provide control or information signals related to the operation or state of the one or more battery packs to the control unit 124-8. In one embodiment, the control unit 124-8 may be configured to interrupt the power from the DC output line of the power interface 124-5 using the DC switch circuit 124-14 when a battery fault (e.g., battery temperature over - limit, battery current over - limit, battery voltage over - limit, battery voltage under - limit, etc.) is detected. The control unit 124-8 may be further configured to interrupt the power from the AC or DC output line of the power interface 124-5 using the DC switch circuit 124-14 and / or the AC switch 124-16 when a tool fault condition (e.g., tool temperature over - limit, tool current over - limit, etc.) is detected.

[0315] In one embodiment, the power unit 124-6 may further be provided with an electromechanical on / off switch 124-12 coupled to the above-described on / off trigger or actuator. The on / off switch simply connects or disconnects the supply of power from the power interface 124-5 to the motor 124-2. Alternatively, the control unit 124-8 may be configured to deactivate the DC switch circuit 124-14 and the AC switch 124-16 until it detects the actuation by the user of the on / off trigger or actuator (or, in the case where the on / off trigger function is built into a variable speed actuator, the initial actuation of the variable speed actuator). The control unit 124-8 may then activate the operation of the motor 124-2 via the DC switch circuit 124-14 or the AC switch 124-16. In this way, the power unit 124-6 may be operable without the electromechanical on / off switch 124-12.

[0316] Referring to FIG. 7A, a variable speed universal motor tool 124 is shown according to one embodiment, in which case the ACH and DC+ power lines are coupled together at a common positive node 124-11a, and the ACL and DC- power lines are coupled together at a common negative node 124-11b. In this embodiment, the on / off switch 124-12 is disposed between the positive common node 124-11a and the motor 124-2. To ensure that only one of the AC or DC power supplies is utilized at any given time, in one embodiment, the control unit 124-8 may be configured to activate only one of the DC switch circuit 124-14 and the AC switch 124-16 at any given time.

[0317] In a further embodiment, as a redundancy measure and to minimize electrical leakage, a mechanical lockout device may be utilized. In an exemplary embodiment, the mechanical lockout device may physically block access to the AC or DC power supply at any given time.

[0318] FIG. 7B shows a variable speed universal motor tool 124 according to an alternative embodiment, in which case the DC power lines DC+ / DC− and the AC power lines ACH / ACL are isolated via a power switching unit 124-15 to ensure that power cannot be supplied simultaneously from both the AC and DC power supplies (even when the power interface 124-5 is coupled to both AC and DC power supplies). The switching unit 124-15 may be configured to include a relay, a single-pole double-throw switch, a double-pole double-throw switch, or a combination thereof, as illustrated and described with reference to FIGS. 6B-6D. The power switching unit 124-15 of FIG. 7B is shown between a power interface 124-5 on one side and a DC switch circuit 124-14 and an AC switch 124-16 on the other side, but it should be understood that the power switching unit 124-15 may alternatively be provided between a DC switch circuit 124-14 and an AC switch 124-16 on one side and a motor 124-2 on the other side, depending on the switching configuration utilized within the power switching unit 124-15.

[0319] As described above, the DC switch circuit 124-14 may include a combination of one or more semiconductor devices. FIGS. 7C-7E illustrate various configurations and embodiments of the DC switch circuit 124-14. In one embodiment shown in FIG. 7C, a combination of an FET and a diode is used in what is known as a chopper circuit, and the control unit 124-8 drives the gate of the FET (via a gate driver not shown) to control the PWM duty cycle of the motor 124-2. In another embodiment shown in FIG. 7D, a combination of two FETs is used in series (i.e., a half-bridge). In this case, the control unit 124-8 can drive the gate of one or both FETs (i.e., single-switch PWM control or PWM control with synchronous rectification). In yet another embodiment shown in FIG. 7E, a combination of four FETs is used as an H-bridge (full-bridge). In this case, the control unit 124-8 may drive the gates of two or four FETs to a PWM duty cycle of 0% to 100% associated with the desired speed of the motor from zero to maximum speed (i.e., with or without synchronous rectification). Note that any type of controllable semiconductor device, such as a BJT or IGBT, may be used instead of the FETs shown in these figures. For a detailed description of these circuits and the associated PWM control mechanisms, reference is made to U.S. Patent No. 8,446,120 entitled "Electronic Switch Module for a Power Tool". The contents of this patent document are hereby incorporated by reference in their entirety.

[0320] Referring again to FIGS. 7A and 7B, the AC switch 124-16 may include a phase-controlled AC power switch such as a triac, SCR, thyristor, etc., configured in series on the AC power line ACH and / or the AC power line ACL. In one embodiment, the control unit 124-8 controls the speed of the motor by switching the motor current on and off at periodic intervals with respect to the zero crossings of the AC current or voltage waveform. The control unit 124-8 may fire the AC switch 124-16 at a conduction angle of 0 to 180 degrees within each AC half-cycle related to the desired speed of the motor from zero to maximum speed. For example, if the desired motor speed is 50% of the maximum speed, the control unit 124-8 may fire the AC switch 124-16 at 90 degrees, which is the midpoint of the half-cycle. Preferably, such periodic intervals are generated to occur in synchronization with the original AC waveform. The conduction angle determines the point within the AC waveform at which the AC switch 124-16 is fired, i.e., turned on, thereby supplying electrical energy to the motor 124-2. The AC switch 124-16 turns off at the end point of the selected period, i.e., at the zero crossing of the AC waveform. Thus, the conduction angle is measured from the firing point of the AC switch 124-16 to the zero crossing. For a detailed description of the phase control of a triac or other phase-controlled AC switch in a power tool, reference is made to U.S. Patent No. 8,657,031 entitled "Universal Control Module", U.S. Patent No. 7,834,566 entitled "Generic Motor Control", and U.S. Patent No. 5,986,417 entitled "Sensorless Universal Motor Speed Controller". Each of these patent documents is hereby incorporated by reference in its entirety.

[0321] As described above, the control unit 124-8 controls the switching operations of both the DC switch circuit 124-14 and the AC switch 124-16. When the tool 124 is coupled to an AC power source, the control unit 124-8 may detect a current through the AC power lines ACH / ACL and set its operating mode to control the AC switch 124-16. In one embodiment, when the tool 124 is coupled to a DC power source, the control unit 124-8 may detect the absence of a zero crossing on the AC power lines ACH / ACL and change its operating mode to control the DC switch circuit 124-14. It should be noted that the control unit 124-8 may set its operating mode by various methods such as detecting a signal from the COMM signal line or detecting a voltage on the DC power lines DC+ / DC-.

[0322] 1. Integrated power switch / diode bridge Referring now to FIGS. 7F-7H, a variable speed universal motor tool 124 is shown in accordance with an alternative embodiment, in which the AC and DC power lines of the power interface 124-5 are coupled to an integrated AC / DC power switching circuit 124-18.

[0323] As shown in FIGS. 7G and 7H, the integrated AC / DC power switching circuit 124-18 includes a semiconductor switch Q1 incorporated within a diode bridge composed of diodes D1 to D4. The semiconductor switch Q1 may be a field effect transistor (FET), as shown in FIG. 7H, or an insulated gate bipolar transistor (IGBT), as shown in FIG. 7G. The semiconductor switch Q1 is disposed at one end between D1 and D3 and at the other end between D2 and D4. The line inputs DC+ and ACH are coupled together to a node of the diode bridge between D1 and D4. The positive motor terminal M+ is coupled to a node of the diode bridge between D2 and D3.

[0324] When the tool 124 is coupled to a DC power supply, in one embodiment, the control unit 124-8 sets its operating mode to the DC mode as described above. In this mode, the control unit 124-8 controls the motor speed by controlling the semiconductor switch Q1 via the PWM technique, i.e., by turning the switch Q1 on and off to provide a pulsed voltage. The PWM duty cycle, or the ratio of the on and off periods within the PWM signal, is selected according to the desired speed of the motor.

[0325] When the tool 124 is coupled to an AC power source, in one embodiment, the control unit 124-8 sets its operating mode to AC as described above. In this mode, the control unit 124-8 controls the semiconductor switch Q1 in a manner similar to the switching operation of a phase-controlled switch such as a triac. Specifically, the switch Q1 is turned on by the control unit 124-8 so as to correspond to the time point of the AC half cycle at which the triac will be properly ignited. The control unit 124-8 continuously maintains the switch Q1 in the on state until it reaches the zero crossing indicating the end of the AC half cycle. At that time point, the control unit 124-8 turns off the switch Q1 so as to correspond to the time point of the current zero crossing. In this way, the control unit 124-8 controls the speed of the motor by operating the switch Q1 within each half cycle so as to control the conduction angle of each AC half cycle according to the desired motor speed.

[0326] When power is supplied via the DC power line DC+ / DC-, the current flows into the motor 124-2 through D1-Q1-D2. As described above, the control unit 124-8 controls the speed of the motor by controlling the PWM duty cycle of the switch Q1. When power is supplied via the AC power line ACH / ACL, the current flows through D1-Q1-D2 in all positive half cycles and through D3-Q1-D4 in all negative half cycles. Therefore, the diode bridge D1-D4 functions to rectify the AC power passing through the switch Q1, but does not rectify the AC power passing through the motor terminals M+ / M-. As described above, the control unit 124-8 controls the speed of the motor by controlling the conduction band of each half cycle via the switch Q1.

[0327] Note that in one embodiment, the control unit 124-8 can perform PWM control on switch Q1 in both AC and DC operation modes. Specifically, instead of controlling the conduction band of the AC line within each half cycle, the control unit 124-8 may select a PWM duty cycle by using the above-described PWM technique to control the speed of the motor.

[0328] Depending on the size and characteristics of the motor 124-2, the motor 124-2 may have an inductive current that is slightly delayed with respect to the AC line current. In the AC operation mode, this current is allowed to decay to zero at the end of each AC half cycle, i.e., after all voltage zero crossings. However, in the DC operation mode, it is desirable to provide a current path for the inductive current of the motor 124-2. Thus, according to one embodiment, a freewheel switch Q2 and a freewheel diode D5 are further provided in parallel with the motor 124-2 to provide a path for the inductive current flowing through the motor 124-2 when Q1 is turned off. In one embodiment, in the AC operation mode, the control unit 124-8 is configured to always keep Q2 in the off state. However, in the DC operation mode, the control unit 124-8 is configured to keep the freewheel switch Q2 in the on state.

[0329] In a further embodiment, the control unit 124-8 is configured to activate Q2 when switch Q1 is stopped, and to activate Q1 when switch Q2 is stopped. In other words, when Q1 is pulse width modulated, the on and off periods of switch Q1 will coincide synchronously with the off and on periods of switch Q2. This ensures that the freewheel current path of Q2 / D5 does not short circuit the motor 124-8 in any Q1 on cycle.

[0330] According to such a configuration, the speed of the motor 124-2 can be controlled regardless of whether the power tool 124 is connected to an AC power source or a DC power source.

[0331] 2. Variable speed universal motor tool having a power source with equivalent voltage ratings In FIGS. 7A, 7B, and 7F described above, the power tool 124 is designed to operate, for example, in a high rated voltage range of 100V to 120V (corresponding to an AC power voltage range of 100V to 120VAC), or more broadly, 90V to 132V (corresponding to ±10% of the AC power voltage range of 100 to 120VAC), and at high power (e.g., 1500 to 2500 watts). Also, the motor 124-2 has an operating voltage or operating voltage range that can be equivalent to, included in, or corresponding to the operating voltage or operating voltage range of the tool 124.

[0332] In one embodiment, the power supply interface 124-5 is configured to provide an AC voltage having a nominal voltage that is significantly different from the nominal voltage provided by the DC power source. For example, the AC power line of the power supply interface 124-5 may provide a nominal voltage within the range of 100 to 120V, and the DC power line may provide a nominal voltage within the range of 60V to 100V (e.g., 72VDC or 90VDC). In another example, the AC power line may provide a nominal voltage within the range of 220 to 240V (e.g., 230V in many European countries or 220V in many African countries), and the DC power line may provide a nominal voltage within the range of 100 to 120V (e.g., 108VDC).

[0333] 3. Variable speed universal motor tool having a power source with different voltage ratings According to an alternative embodiment of the present invention, the voltage provided by the AC power supply has a nominal voltage that is significantly different from the nominal voltage provided by the DC power supply. For example, the AC power line of the power interface 124-5 may provide a nominal voltage within the range of 100 to 120V, and the DC power line may provide a nominal voltage within the range of 60V to 100V (e.g., 72VDC or 90VDC). In another example, the AC power line may provide a nominal voltage within the range of 220 to 240V (e.g., 230V in many European countries or 220V in many African countries), and the DC power line may provide a nominal voltage within the range of 100 to 120V (e.g., 108VDC).

[0334] The operation of the power tool motor 124-2 at significantly different voltage levels may result in a large difference in the performance of the power tool, particularly in the rotational speed of the motor, which may be significant and, in some cases, may not be satisfactory for the user. Also, the supply of a voltage level outside the operating voltage range of the motor 124-2 may damage the motor and related switching components. Therefore, in one embodiment of the present invention described herein, the motor control circuit 124-4 is configured to optimize the supply of power to the motor 124-2 (and thus the motor performance) according to the nominal voltage of the AC or DC power line so that the motor 124-2 provides substantially uniform speed and power performance in a manner satisfactory to the end user, regardless of the nominal voltage provided on the AC or DC power line.

[0335] In this embodiment, the motor 124-2 may be designed and configured to operate in a voltage range that includes the nominal voltage of the DC power line. In an exemplary embodiment, the motor 124-2 includes the nominal voltage of the DC power line of the power interface 124-5 (e.g., 72 VDC or 90 VDC), but is less than the nominal voltage of the AC power line (e.g., 220 V - 240 V), and may be designed to operate in a voltage range of, for example, 60 V - 90 V (or, more broadly, 54 V - 99 V which is this ±10%). In another exemplary embodiment, the motor 124-2 includes the nominal voltage of the DC power line of the power interface 124-5 (e.g., 108 VDC), but is less than the 220 - 240 V nominal voltage range of the AC power line, and may be designed to operate in a voltage range of 100 V - 120 V (or, more broadly, 90 V - 132 V which is this ±10%).

[0336] In one embodiment, so that the motor 124-2 operates with the nominal voltage of the higher AC power line, the control unit 124-8 may be configured to set a fixed maximum conduction band for the phase-controlled AC switch 124-16 corresponding to the operating voltage of the tool 124. Specifically, the control unit 124-8 may set a fixed ignition angle corresponding to the maximum speed of the tool (e.g., at a 100% trigger displacement), thereby resulting in a conduction band of less than 180 degrees within each AC half-cycle at the maximum no-load speed. This enables the control unit 124-8 to optimize the power supply to the motor by effectively reducing the total voltage provided from the AC power supply to the motor 124-2.

[0337] For example, in the case of the motor 124-2 that has an operating voltage range of 60 to 100V but receives AC power with a nominal voltage of 100 to 120V, the conduction band of the AC switch 124-16 may be set to a maximum value of about 120 degrees. In other words, the arcing angle of the AC switch 124-16 may be varied from 60 degrees (corresponding to a conduction angle of 120 degrees) at the desired maximum speed to 180 degrees (corresponding to a conduction angle of 0 degrees) at zero speed. By setting the maximum arcing angle to about 60 degrees, the AC voltage supplied to the motor at the desired maximum speed is substantially in the range of 70 to 90V, which corresponds to the operating voltage of the tool 124.

[0338] In this way, the motor control circuit 124-4 optimizes the supply of power to the motor 124-2 according to the nominal voltage of the AC or DC power line so that the motor 124-2 provides substantially uniform speed and power performance in a manner satisfactory to the end user, regardless of the nominal voltage provided on the AC or DC power line.

[0339] C. Constant-Speed AC / DC Power Tools with Brushed PMDC Motors Next, referring to FIGS. 8A and 8B, a third subset of AC / DC power tools having a brushed motor 122 includes a constant speed AC / DC power tool 125 having a permanent magnet DC (PMDC) brushed motor that tends to have better efficiency than a universal motor (hereinafter referred to as a constant speed PMDC tool 125). These include corded / cordless (AC / DC) power tools that operate at a constant speed in a no-load (or constant load) state, and include a PMDC brushed motor 125-2 configured to operate at a high rated voltage (e.g., 100V - 120V) and high power (e.g., 1500 - 2500 watts). The PMDC brushed motor generally includes a wound rotor coupled to a commutator and a stator having a permanent magnet fixed therein. The PMDC motor operates only on DC power, as its name indicates. This is because the permanent magnet on the stator does not change polarity, and as the AC power changes from the positive half-cycle to the negative half-cycle, the change in polarity within the brush causes the motor to stop. For this reason, in one embodiment, as shown in FIGS. 8A and 8B, the power from the AC power source is passed through a rectifier circuit 125-20 to convert or remove the negative half-cycle of the AC power. In one embodiment, the rectifier circuit 125-20 may be a full-wave rectifier configured to rectify the AC voltage waveform by converting the negative half-cycle of the AC power to a positive half-cycle. Alternatively, in one embodiment, the rectifier circuit 125-20 may be a half-wave rectifier circuit to remove the half-cycle of the AC power. In one embodiment, a link capacitor or smoothing capacitor (not shown) may be further provided in the rectifier circuit 125-20. In one embodiment, the constant speed PMDC motor tool 125 may include high-power tools for high-power applications such as concrete hammers, mitre saws, table saws, vacuum cleaners, blowers, and lawn mowers.

[0340] Many aspects of the constant speed PMDC motor tool 125 are similar to those of the constant speed universal motor tool 123 described above with reference to FIGS. 6A-6E. In one embodiment, the constant speed PMDC motor tool 125 includes a motor control circuit 125-4 that operates the PMDC motor 125-2 at a constant speed in a no-load state. The power tool 125 further includes a power interface 125-5 configured to receive power from one or more of the DC power source and / or AC power source described above. The power interface 125-5 is electrically coupled to the motor control circuit 125-4 by DC power lines DC+ and DC- (for supplying power from the DC power source) and by AC power lines ACH and ACL (for supplying power from the AC power source).

[0341] In one embodiment, the motor control circuit 125-4 includes a power unit 125-6. The power unit 125-6 is provided in series with the motor 125-2 and may include an electromechanical on / off switch 125-12 coupled to an on / off trigger or actuator (not shown). Additionally and / or alternatively, the power unit 125 may include a power switch 125-13 coupled to the DC power lines DC+ / DC- and the control unit 125-8. In one embodiment, a control unit 125-8 may be provided to monitor the state of the power tool 125 and / or the battery. In one embodiment, the control unit 125-8 may be coupled to an element of the tool 125, such as a thermistor inside the tool. Also, in one embodiment, the control unit 125-8 may be coupled to one or more battery packs via a communication signal line COMM provided from the power supply interface 125-5. The COMM signal line may provide control or information signals related to the operation or state of the one or more battery packs to the control unit 125-8. In one embodiment, the control unit 125-8 is configured to interrupt the power from the DC+ output line of the power supply interface 125-5 using the power switch 125-13 when a fault condition of the tool (e.g., tool temperature overrun, tool current overrun, etc.) or a fault condition of the battery (e.g., battery temperature overrun, battery current overrun, battery voltage overrun, battery voltage underrun, etc.) is detected. In one embodiment, the power switch 125-13 may include a FET or other controllable switch controlled by the control unit 125-8. Note that in an alternative embodiment, the power switch 125-13 may be provided between both the AC power line ACH / ACL and the DC power lines DC+ / DC- on one side and the motor 125-2 on the other side such that the control unit 125-8 allows interruption of power from an AC or DC power source in the event of a tool fault condition.Also, in another embodiment, the constant speed PMCM motor tool 125 may be provided without an on / off switch 125-12, and the control unit 125-8 may be configured to initiate activation of the power switch 125-13 when an on / off trigger or actuator is actuated by the user. In other words, the power switch 125-13 may be used for on / off and fault condition control. It should be noted that the power switch 125-13 is not used to control the variable speed control (e.g., PWM control) of the motor 125-2 in this embodiment.

[0342] Referring to FIG. 8A, a constant speed PMDC motor tool 125 is shown according to one embodiment, where the DC+ power line and the V+ output of the rectifier circuit 125-20 (which carries the rectified ACH power line) are coupled together at a common positive node 125-11a, and the DC- power line and the Gnd output from the rectifier circuit 125-20 (corresponding to the ACL power line) are coupled together at a common negative node 125-11b. In this embodiment, the on / off switch 125-12 is disposed between the positive common node 125-11a and the motor 125-2. To ensure that only one of the AC or DC power supplies is utilized at any given point in time, in one embodiment, a mechanical lockout device may be utilized. In an exemplary embodiment, the mechanical lockout device may physically block access to one of the AC or DC power supplies at any given point in time.

[0343] In FIG. 8B, a constant speed PMDC motor tool 125 is shown according to an alternative embodiment, where the DC power lines DC+ / DC- and the AC power lines ACH / ACL are isolated via a power switching unit 125-15 to ensure that power cannot be supplied simultaneously from both the AC and DC power sources (even when the power supply interface 125-5 is coupled to both AC and DC power sources). The power switching unit 125-15 may be configured in the same way as any of the configurations of the power switching unit 123-15 in FIGS. 6B-6D. Note that the power switching unit 125-15 may be arranged between the AC power lines ACH / ACL and the rectifier circuit 125-20 in an alternative embodiment. In yet another embodiment, the power switching unit 125-15 may be arranged between the power switch 125-13 and the on / off switch 125-12.

[0344] The tools 125 in FIGS. 8A and 8B are provided with a control unit 125-8 and a power switch 125-13 to interrupt power supply in case of a fault condition of the tool or the battery. However, it should be understood that the tool 125 may be provided without the control unit 125-8 and the power switch 125-13. For example, one or more batteries may be provided with their own controller to monitor their fault condition and manage their operation.

[0345] 1. Constant speed PMDC tool with a power source having an equivalent voltage rating In FIGS. 8A and 8B described above, the power tool 125 is designed to operate at a high voltage rating range, such as 100V - 120V (more broadly, 90V - 132V corresponding to ±10% of the AC power voltage range of 100 - 120VAC), and at high power (e.g., 1500 - 2500 watts), corresponding to an AC power voltage range. Also, the motor 125-2 has an operating voltage or operating voltage range that can be equivalent to, included in, or corresponding to the operating voltage or operating voltage range of the tool 125.

[0346] In one embodiment, the power supply interface 125-5 is configured to provide an AC power line having a nominal voltage in the range of 100-120V from an AC power supply (e.g., 120VAC at 50-60Hz in the United States, or 100VAC in Japan), or to provide a DC power line having a nominal voltage in the range of 100-120V from a DC power supply (e.g., 108VDC). In other words, both the DC nominal voltage and the AC nominal voltage provided through the power supply interface 125-5 correspond to (e.g., match, overlap with, or are included in) the operating voltage range of the power tool 125 (i.e., the high rated voltage of 100V-120V, or more broadly, about 90V-132V). The nominal voltage of 120VAC corresponds to an average voltage of about 108V when measured in the positive half cycle of the AC sine wave, and it should be noted that this provides equivalent speed performance to 108VDC power.

[0347] 2. Constant speed PMDC tool with power supplies having different voltage ranges According to another embodiment of the present invention, the voltage provided by the AC power supply has a nominal voltage that is significantly different from the nominal voltage provided by the DC power supply. For example, the AC power line of the power supply interface 125-5 may provide a nominal voltage in the range of 100-120V, and the DC power line may provide a nominal voltage in the range of 60V-100V (e.g., 72VDC or 90VDC). In another example, the AC power line may provide a nominal voltage in the range of 220-240V, and the DC power line may provide a nominal voltage in the range of 100-120V (e.g., 108VDC).

[0348] The operation of the power tool motor 125-2 at significantly different voltage levels can result in a large difference in the performance of the power tool, particularly in the rotational speed of the motor, which can be significant and, in some cases, unsatisfactory for the user. Also, supplying a voltage level outside the operating voltage range of the motor 125-2 can damage the motor and associated switching components. Thus, in one embodiment of the invention described herein, the motor control circuit 125-4 is configured to optimize the supply of power (and thus motor performance) to the motor 125-2 in a manner satisfactory to the end user, substantially uniformly in speed and power performance, regardless of the nominal voltage provided on the AC or DC power line, in response to the nominal voltage of the AC or DC power line.

[0349] In this embodiment, the power tool motor 125-2 may be designed and configured to operate in a voltage range that includes the nominal voltage of the DC power line. In one exemplary embodiment, the motor 125-2 may be designed to operate in a voltage range of, for example, 60V to 90V (or, more broadly, 54V to 99V which is this ±10%), which includes the nominal voltage of the DC power line of the power supply interface 125-5 (e.g., 72VDC or 90VDC) but is less than the nominal voltage of the AC power line (e.g., 220V - 240V). In another exemplary embodiment, the motor 125-2 may be designed to operate in a voltage range of 100V to 120V (or, more broadly, 90V to 132V which is this ±10%), which includes the nominal voltage of the DC power line of the power supply interface 125-5 (e.g., 108VDC) but is less than the nominal voltage of the 220 - 240V AC power line.

[0350] In one embodiment, to operate motor 125-2 at a higher nominal voltage of the AC power line, motor control circuit 125-4 may be designed to optimize the supply of power to motor 125-2 in accordance with the various embodiments described herein.

[0351] In one embodiment, rectifier circuit 125-20 may be provided as a half-wave diode bridge rectifier. As those skilled in the art will recognize, a half-wave rectified waveform will have approximately half the average nominal voltage of the input AC waveform. Thus, in a scenario where the nominal voltage of the AC power line is in the range of 220 - 240V and motor 125-2 is designed to operate in a voltage range of 100V - 120V, rectifier circuit 125-20 may be configured as a half-wave rectifier to provide motor 125-2 with an average nominal AC voltage of 110V - 120V, which is within the operating voltage range of power tool 125.

[0352] In another embodiment, as shown in FIG. 8C, the V+ output of rectifier circuit 125-20 may be provided as an input to power switch 125-13, and control unit 125-8 may be configured to pulse-width modulate (PWM) the V+ signal at a fixed duty cycle corresponding to the operating voltage of tool 125. For example, in the case of tool 125 having an operating voltage range of 60 - 100V but receiving AC power having a nominal voltage of 100 - 120V, when control unit 125-8 detects an AC current on the AC power line of power interface 125-5, control unit 125-8 controls the PWM switching operation of power switch 125-13 at a fixed duty cycle within the range of 60% - 80% (e.g., 70%). As a result, when operating from an AC power source, a voltage level of approximately 70 - 90V corresponding to the operating voltage of tool 125 is supplied to motor 125-2.

[0353] In yet another embodiment, as shown in FIG. 8D, the tool 125 may further be provided with a phase-controlled AC switch 125-16. In one embodiment, the AC switch 125-16 is arranged in series with the V+ output of the rectifier circuit 125-20. In one embodiment, the AC switch 125-16 may include a triac or SRC switch controlled by the control unit 125-8. In one embodiment, the control unit 125-8 may be configured to set a fixed conduction band (or firing angle) of the AC switch 125-16 corresponding to the operating voltage of the tool 125. For example, in the case of the motor 125-2 that receives AC power having a nominal voltage of 100 - 120V but an operating voltage range of 60V - 100V, the conduction band of the AC switch 125-16 may be fixedly set at approximately 120 degrees. In other words, the firing angle of the AC switch 125-16 may be set at 60 degrees. By setting the firing angle at approximately 60 degrees, the AC voltage supplied to the motor 125-2 will be within a range of approximately 70 - 90V corresponding to the operating voltage of the motor 125-2. In another example, in the case of the motor 125-2 that receives AC power having a nominal voltage of 220 - 240V but an operating voltage range of 100 - 120V, the conduction band of the AC switch 125-16 may be fixedly set at approximately 90 degrees. In other words, the firing angle of the AC switch 125-16 may be set at 90 degrees. By setting the firing angle at 90 degrees, the AC voltage supplied to the motor 125-2 will be within a range of approximately 100 - 120V corresponding to the operating voltage of the motor 125-2. In this way, the control unit 125-8 optimizes the power supply to the motor 125-2.

[0354] In this way, the motor control circuit 125-4 optimizes the power supply to the motor 125-2 according to the nominal voltage of the AC or DC power line so that the motor 125-2 provides substantially uniform speed and power performance in a manner satisfactory to the end user, regardless of the nominal voltage provided on the AC or DC power line.

[0355] D. Variable - speed AC / DC power tools with brushed DC motors Next, referring to FIGS. 9A - 9B, a fourth subset of AC / DC power tools having a brushed motor 122 includes a variable - speed AC / DC power tool 126 having a PMDC motor (also referred to herein as variable - speed PMDC motor tool 126). These include corded / or cordless (AC / DC) power tools that operate at variable speeds in no - load conditions and include a brushed permanent - magnet DC (PMDC) motor 126 - 2 configured to operate at a high rated voltage (e.g., 100 - 120V) and high power (e.g., 1500 - 2500 watts). As described above, a PMDC - brushed motor generally includes a wound rotor coupled to a commutator and a stator having a permanent magnet fixed therein. A PMDC motor operates by DC power only, because the permanent magnet on the stator does not change polarity, and as the AC power changes from the positive half - cycle to the negative half - cycle, the polarity change in the brush causes the motor to stop. For this reason, in one embodiment, as shown in FIGS. 9A and 9B, the power from the AC power source is passed through a rectifier circuit 126 - 20 to convert or remove the negative half - cycle of the AC power. In one embodiment, the rectifier circuit 126 - 20 may be a full - wave rectifier to convert the negative half - cycle of the AC power to the positive half - cycle. Alternatively, in one embodiment, the rectifier circuit 126 - 20 may be a half - wave rectifier circuit to remove the half - cycle of the AC power. In one embodiment, the variable - speed PMDC motor tool 126 may include high - power tools having variable - speed control, such as a concrete drill, a hammer, a grinder, a saw, etc.

[0356] Many aspects of the variable speed PMDC motor tool 126 are similar to those of the variable speed universal motor tool 124 described above with reference to FIGS. 7A-7E. In one embodiment, the variable speed PMDC motor tool 126 is provided with a variable speed actuator (not shown, e.g., a trigger switch, a contact sensing switch, a capacitive switch, a gyroscope, or other variable speed input mechanism) that can be engaged by the user. In one embodiment, the variable speed actuator is coupled to or includes a potentiometer or other circuit for generating a variable speed signal (e.g., a variable voltage signal, a variable current signal, etc.) indicative of a desired speed of the motor 126-2. In one embodiment, the variable speed PMDC motor tool 126 may further be provided with an on / off trigger or actuator (not shown) that enables the user to start the motor 126-2. Alternatively, the on / off trigger function may be incorporated into the variable speed actuator such that an initial actuation of the variable speed trigger by the user functions to start the motor 126-2 (i.e., there is no separate on / off actuator).

[0357] In one embodiment, the variable speed PMDC motor tool 126 includes a motor control circuit 126-4 that operates the PMDC motor 126-2 at a variable speed in a no-load or constant load state. The power tool 126 further includes a power supply interface 126-5 configured to receive power from one or more of the DC power sources and / or AC power sources described above. The power supply interface 126-5 is electrically coupled to the motor control circuit 126-4 by DC power lines DC+ and DC- (for supplying power from a DC power source) and by AC power lines ACH and ACL (for supplying power from an AC power source). The AC power lines ACH and ACL are input to a rectifier circuit 126-20.

[0358] Since the AC line is passed through the rectifier circuit 126-20, it no longer contains negative components and thus, in one embodiment, does not operate with the phase-controlled switch for variable speed control. Thus, in one embodiment, instead of the separate DC and AC switch circuits shown in FIGS. 7A and 7B, the motor control circuit 126-4 is provided with a PWM switching circuit 126-14. The PWM switching circuit may include, for example, a combination of one or more power semiconductor devices (e.g., diodes, FETs, BJTs, IGBTs, etc.) configured as a chopper circuit, a half bridge, or an H-bridge as shown in FIGS. 7C to 7E.

[0359] In one embodiment, the motor control circuit 126-4 further includes a control unit 126-8. The control unit 126-8 may be configured to control the switching operation of the PWM switching circuit 126-14. In one embodiment, the control unit 126-8 may include a microcontroller or a similar programmable module configured to control the gate of the power switch. In one embodiment, the control unit 126-8 is configured to control the PWM duty cycle of one or more semiconductor switches in the PWM switching circuit 126-14 to control the speed of the motor 126-2. In addition to this, the control unit 126-8 monitors and manages the operation of a power tool or a battery pack coupled to the power interface 126-5, and interrupts the power to the motor 126-2 in the case of a fault condition of the tool or the battery (such as battery temperature over - temperature, tool temperature over - temperature, battery current over - current, tool current over - current, battery voltage over - voltage, battery voltage under - voltage, etc.). In one embodiment, the control unit 126-8 may be coupled to one or more battery packs via a communication signal line COMM provided from the power interface 126-5. The COMM signal line may provide control or information signals related to the operation or state of one or more battery packs to the control unit 126-6. In one embodiment, the control unit 126-6 may be configured to interrupt the power from the DC output line of the power interface 126-5 when the COMM line indicates a battery fault or failure condition.

[0360] Similar to the variable speed universal motor tool 124 described above with reference to FIGS. 7A-7E, the variable speed PMDC motor tool 126 may further be provided with an electromechanical on / off switch 126-12 coupled to the on / off trigger or actuator described above. The on / off switch 126-12 simply connects or disconnects the supply of power from the power source to the motor 126-2. Alternatively, the tool 126 may be provided without the on / off switch 126-12. In this case, the control unit 126-8 may be configured to deactivate the PWM switching circuit 126-14 until it detects actuation by the user of the on / off trigger or actuator (or, if the on / off trigger function is incorporated within the variable speed actuator, initial actuation of the variable speed actuator). The control circuit 126-8 may then activate the operation of the motor 126-2 by activating one or more of the switches within the PWM switching circuit 126-14.

[0361] Referring to FIG. 9A, the tool 126 is shown according to one embodiment, in which the ACH and DC+ power lines are coupled together at a common positive node 126-11a and the ACL and DC- power lines are coupled together at a common negative node 126-11b. In this embodiment, the on / off switch 126-12 and the PWM switching circuit 126-14 are disposed between the positive common node 126-11a and the motor 126-2. To ensure that only one of the AC or DC power sources is utilized at any given time and to minimize leakage, in one embodiment, a mechanical lockout device (the embodiment of which will be described in more detail later) may be utilized. In an exemplary embodiment, the mechanical lockout device may physically block access to the AC or DC power source at any given time.

[0362] In FIG. 9B, a variable speed PMDC motor tool 126 is shown according to an alternative embodiment, where the DC power lines DC+ / DC− and the AC power lines ACH / ACL are isolated from each other via a power switching unit 126-15 to ensure that power cannot be supplied simultaneously from both the AC power source and one or more battery packs (even when the power interface is coupled to both AC and DC power sources). The power switching unit 126-15 may be configured in the same manner as any of the configurations of the power switching unit 123-15 of FIGS. 6B-6D, i.e., as a relay, a single-pole double-throw switch, a double-pole double-throw switch, or a combination thereof. The power switching unit 126-15 of FIG. 9B is shown between the rectifier circuit 126-20 and the PWM switching circuit 126-14, but it should be understood that the power switching unit 126-15 may alternatively be provided directly on the AC and DC line outputs of the power interface 126-5.

[0363] 1. Variable speed brushed DC tool with a power source having an equivalent voltage rating In FIGS. 9A and 9B described above, the power tool 126 is designed to operate in a high voltage rating range of, for example, 100V - 120V (corresponding to the AC power voltage range of 100V - 120VAC), and more broadly, 90V - 132V (corresponding to ±10% of the AC power voltage range of 100 - 120VAC), and at high power (e.g., 1500 - 2500 watts). Specifically, the components of the motor 126-2 and the power unit 126-6 of the power tool 126 are designed and optimized to handle a high voltage rating of 100 - 120V, preferably 90V - 132V. Also, the motor 126-2 has an operating voltage or operating voltage range that can be equivalent to, included in, or corresponding to the operating voltage or operating voltage range of the tool 126.

[0364] In one embodiment, the power supply interface 126-5 is configured to provide an AC power line having a nominal voltage in the range of 100 to 120 V...

Claims

1. A power tool system comprising: a multi-voltage battery pack for use with a first power tool, the first power tool having a first battery pack interface and configured to operate at a first operating voltage; and A second power tool configured to be used with the battery pack having the multiple voltages, The power tool system includes both the battery pack having the multiple voltages and the second power tool, the second power tool has a second battery pack interface and is configured to operate at a second operating voltage higher than the first operating voltage. the second power tool; having The battery pack having multiple voltages includes: Housing and a first string of battery cells disposed within the housing in an electrically series arrangement, the first string of battery cells having a first positive voltage terminal and a first negative voltage terminal; a second string of battery cells disposed within the housing in an electrically series arrangement, the second string of battery cells having a second positive voltage terminal and a second negative voltage terminal; Power tool interface and having the power tool interface and the second battery pack interface are configured and arranged to be mechanically and electrically coupled to each other; when the second battery pack interface is coupled to the power tool interface, the first positive voltage terminal is electrically connected to the second negative voltage terminal, and the first and second strings of battery cells are electrically connected to each other in a series connection configuration to supply the second operating voltage to the second power tool; the power tool interface is further configured to be couplable with the first battery pack interface, the first battery pack interface being shaped and configured to mate with a second power tool interface of a battery pack having a single voltage, the battery pack having a single voltage being configured to provide the first operating voltage but not the second operating voltage; the power tool interface is configured and adapted to be mechanically and electrically coupled to the first battery pack interface; when the first battery pack interface is coupled to the power tool interface, the first and second positive voltage terminals are electrically connected to each other and the first and second negative voltage terminals are electrically connected to each other, such that the first and second battery cell strings are electrically connected to each other in a parallel connection configuration to supply the first operating voltage to the first power tool; the power tool interface and the second power tool interface are interchangeably coupleable to the first battery pack interface, such that the first power tool can be operated with either the battery pack having the multiple voltages or the battery pack having the single voltage. Power tool system.

2. The power tool system according to claim 1, the second power tool interface of the battery pack having the single voltage is configured to be mechanically incompatible with the second battery pack interface of the second power tool; the second power tool interface of the battery pack having the single voltage is configured to be incapable of being electrically coupled to the second battery pack interface of the second power tool; The power tool interface has a slot in the housing; the second battery pack interface of the second power tool has a downwardly extending protrusion shaped and configured to mate with a slot in the housing of the multiple voltage battery pack when coupled with the power tool interface; the second battery pack interface includes a plurality of rail portions and a plurality of groove portions; the power tool interface of the multiple voltage battery pack is shaped and configured to selectively mechanically mate with (1) a plurality of complementary rails and grooves on the first battery pack interface and (2) the plurality of rails and grooves on the second battery pack interface of the second power tool; the power tool interface of the multiple voltage battery pack includes a latch portion shaped and configured to maintain a mechanical and electrical connection between the power tool interface and the first or second battery pack interface; the second power tool interface of the single voltage battery pack has a plurality of rails and a plurality of grooves shaped and configured to mate with the plurality of rails and the plurality of grooves complementary to the first battery pack interface; the first battery cell string includes five battery cells arranged in a first string within the housing; the second battery cell string includes five battery cells arranged in a second string within the housing; the second row is disposed above the first row, the first row of battery cells and the second row of battery cells are arranged in a 2 x 5 matrix within the housing; the first row of battery cells and the second row of battery cells each define a longitudinal axis that is parallel to one another; the multi-voltage battery pack having first and second opposing sides; each of the battery cells in the first battery cell string and the second battery cell string has a positive voltage terminal and a negative voltage terminal; positive voltage terminals of three of the five battery cells in the first battery cell string are disposed on the first side of the multiple voltage battery pack; positive voltage terminals of three of the five battery cells in the second battery cell string are disposed on the first side of the multiple voltage battery pack; negative voltage terminals of two of the five battery cells in the first battery cell string are disposed on the first side of the battery pack having multiple voltages; negative voltage terminals of two of the five battery cells in the second battery cell string are disposed on the first side of the multiple voltage battery pack; a negative voltage terminal of the battery cell in the first string of battery cells on the first side is vertically aligned with a corresponding negative voltage terminal of the battery cell in the second string of battery cells on the first side; a positive voltage terminal of the battery cell in the first string of battery cells on the first side is vertically aligned with a corresponding positive voltage terminal of the battery cell in the second string of battery cells on the first side; the second power tool includes a conductive jumper having first and second contacts electrically interconnected; the second battery pack interface of the second power tool includes the electrically interconnected first and second contacts of the conductive jumper, such that when the power tool interface is coupled to the second battery pack interface, the first and second contacts of the conductive jumper are in electrical contact with the first positive voltage terminal and the second negative voltage terminal, respectively, and the first and second strings of battery cells are electrically connected in series with each other via the conductive jumper of the second power tool; the first operating voltage is from about 17 to about 20 volts, and the second operating voltage is from about 34 to about 40 volts; the second power tool has a power tool housing; the second battery pack interface is disposed on the power tool housing; the multi-voltage battery pack has an open circuit configuration in which the first and second battery cell strings are not electrically connected in parallel or in series with each other; the power tool interface having a first row of electrical terminals shaped and configured to physically and electrically contact corresponding electrical contacts of the second power tool when mechanically and electrically coupled with the second battery pack interface; the power tool interface having a second row of electrical terminals shaped and configured to physically and electrically contact corresponding electrical contacts of the second power tool when mechanically and electrically coupled with the second battery pack interface; the first column is vertically offset from the second column; a plurality of the electrical terminals in the first row of electrical terminals constitute signal terminals; a plurality of electrical terminals in the second row of electrical terminals defining first and second terminals; the first terminal of the second string of electrical terminals is electrically connected to the first positive voltage terminal of the first string of battery cells; the second terminal of the second string of electrical terminals is electrically connected to the second negative voltage terminal of the second string of battery cells; the first row of electrical terminals being horizontally spaced apart; the second row of electrical terminals being horizontally spaced apart; Power tool system.

3. 2. The power tool system of claim 1, wherein the second power tool interface of the battery pack having the single voltage is configured to be mechanically incompatible with the second battery pack interface of the second power tool.

4. 4. The power tool system of claim 3, wherein the second power tool interface of the battery pack having the single voltage is configured so as not to be electrically connectable to the second battery pack interface of the second power tool.

5. The power tool system according to claim 4, The power tool interface has a slot in the housing; the second battery pack interface of the second power tool having a downwardly extending protrusion shaped and configured to mate with a slot in the housing of the multiple voltage battery pack when coupled with the power tool interface; Power tool system.

6. 6. The power tool system of claim 5, wherein the first battery pack interface of the first power tool does not have a protrusion shaped and configured to mate with a slot in the housing when mechanically and electrically coupled to the power tool interface.

7. 6. The power tool system of claim 5, wherein the second power tool interface has a physical structure that occupies a space corresponding to a location of the slot in the power tool interface.

8. The power tool system according to claim 1, the second battery pack interface includes a plurality of rail portions and a plurality of groove portions; the power tool interface of the multiple voltage battery pack includes: (1) a plurality of rails and a plurality of grooves formed in a complementary shape on the first battery pack interface; and (2) a plurality of rails and a plurality of grooves formed and configured to selectively mechanically mate with the plurality of rails and the plurality of grooves on the second battery pack interface; the power tool interface of the multiple voltage battery pack includes a latch portion shaped and configured to maintain a mechanical and electrical connection between the power tool interface and the first or second battery pack interface. Power tool system.

9. 9. The power tool system of claim 8, wherein the second power tool interface of the single voltage battery pack has a plurality of rail portions and a plurality of grooves shaped and configured to mate with the plurality of rail portions and the plurality of grooves formed in a complementary shape on the first battery pack interface.

10. The power tool system according to claim 1, the first battery cell string includes n battery cells arranged in a first string within the housing; the second battery cell string includes n battery cells arranged in a second string within the housing; the second row is disposed above the first row, n is an integer of 3 or more; Power tool system.

11. The power tool system according to claim 10 , wherein the first row of battery cells and the second row of battery cells are arranged in a 2×n matrix within the housing.

12. The power tool system according to claim 1, the first battery cell string has five battery cells; the second battery cell string has five battery cells; Power tool system.

13. The power tool system according to claim 12, the first row of battery cells and the second row of battery cells each define a longitudinal axis that is parallel to one another; the multi-voltage battery pack having first and second opposing sides; each of the battery cells in the first battery cell string and the second battery cell string has a positive voltage terminal and a negative voltage terminal; positive voltage terminals of three of the five battery cells in the first battery cell string are disposed on the first side of the multiple voltage battery pack; positive voltage terminals of three of the five battery cells in the second battery cell string are disposed on the first side of the multiple voltage battery pack; negative voltage terminals of two of the five battery cells in the first battery cell string are disposed on the first side of the battery pack having multiple voltages; negative voltage terminals of two of the five battery cells in the second battery cell string are disposed on the first side of the multiple voltage battery pack; a negative voltage terminal of the battery cell in the first string of battery cells on the first side is vertically aligned with a corresponding negative voltage terminal of the battery cell in the second string of battery cells on the first side; a positive voltage terminal of the battery cell in the first string of battery cells on the first side is vertically aligned with a corresponding positive voltage terminal of the battery cell in the second string of battery cells on the first side. Power tool system.

14. The power tool system according to claim 1, the second power tool includes a conductive jumper having first and second contacts electrically interconnected; the second battery pack interface of the second power tool includes the electrically interconnected first and second contacts of the conductive jumper, such that when the power tool interface is coupled to the second battery pack interface, the first and second contacts of the conductive jumper are in electrical contact with the first positive voltage terminal and the second negative voltage terminal, respectively, and the first and second strings of battery cells are electrically connected in series with each other via the conductive jumper of the second power tool. Power tool system.

15. 2. The power tool system of claim 1, wherein the first operating voltage is from about 17 to about 20 volts, and the second operating voltage is from about 34 to about 40 volts.

16. The power tool system according to claim 1, the second power tool has a power tool housing; The second battery pack interface is disposed on the power tool housing.

17. 2. The power tool system according to claim 1, wherein the battery pack having multiple voltages has an open circuit configuration in which the first and second battery cell strings are not electrically connected in parallel or in series to each other.

18. 18. The power tool system of claim 17, wherein the power tool interface and the second battery pack interface are configured and arranged such that when the power tool interface is decoupled from the second battery pack interface, the multiple voltage battery pack changes from a series connection configuration to the open circuit configuration.

19. 20. The power tool system of claim 18, wherein the power tool interface is configured and arranged such that, when uncoupled from the second battery pack interface, the battery packs having the multiple voltages are sequentially changed from (1) the series connection configuration to (2) the open circuit configuration to (3) the parallel connection configuration.

20. The power tool system according to claim 1, the power tool interface having a first row of electrical terminals shaped and configured to physically and electrically contact corresponding electrical contacts of the second power tool when mechanically and electrically coupled with the second battery pack interface; the power tool interface having a second row of electrical terminals shaped and configured to physically and electrically contact corresponding electrical contacts of the second power tool when mechanically and electrically coupled with the second battery pack interface; a top of the first row is vertically offset from a top of the second row. Power tool system.

21. 21. The power tool system of claim 20, a plurality of the electrical terminals in the first row of electrical terminals constitute signal terminals; a plurality of electrical terminals in the second row of electrical terminals defining first and second terminals; the first terminal of the second string of electrical terminals is electrically connected to the first positive voltage terminal of the first string of battery cells; the second terminal of the second string of electrical terminals is electrically connected to the second negative voltage terminal of the second string of battery cells. Power tool system.

22. 21. The power tool system of claim 20, the housing has a first row of slots; a plurality of electrical terminals in the first row of electrical terminals disposed in respective slots in the first row of slots; the housing has a second row of slots; a plurality of electrical terminals in the second row of electrical terminals disposed in respective slots in the second row of slots; a top of the first row of slots is vertically offset from a top of the second row of slots. Power tool system.

23. The power tool system according to claim 1, the power tool interface having a first row of electrical contacts shaped and configured to make physical and electrical contact with corresponding electrical contacts of the second power tool when mechanically and electrically coupled with the second battery pack interface; the power tool interface having a second row of electrical contacts shaped and configured to physically and electrically contact corresponding electrical contacts of the second power tool when mechanically and electrically coupled with the second battery pack interface; the first column is vertically offset from the second column. Power tool system.

24. A power tool system comprising: A battery pack having multiple voltages; a second power tool having a plurality of grooves, a plurality of rails, and a plurality of electrical terminals; having The battery pack having multiple voltages includes: a housing having a bottom wall, a pair of side walls, a pair of end walls, and a top wall, the bottom wall, the pair of side walls, the pair of end walls, and the top wall defining a receptacle; an electro-mechanical interface coupled to the top wall, a terminal block having a plurality of slots for receiving a plurality of electrical terminals; a pair of longitudinal rail portions extending along the terminal block, the pair of longitudinal grooves being defined between the rail portions and the top wall portion; and a latch portion; the electromechanical interface is configured to be coupled to a first power tool operating at a first operating voltage by sliding the pair of longitudinal rail portions and the pair of longitudinal groove portions into corresponding groove portions and rail portions of the first power tool, whereby a plurality of electrical terminals of the first power tool are received in the slots of the electromechanical interface and engage with the plurality of electrical terminals of the battery pack, and further the latch portion engages with the first power tool to maintain a coupling between the electromechanical interface and the first power tool; the electromechanical interface is configured to be coupled to a second power tool by sliding the pair of longitudinal rail portions and the pair of longitudinal groove portions into the plurality of groove portions and the plurality of rail portions of the second power tool operating at a second, different operating voltage, whereby the plurality of electrical terminals of the second power tool are received in the slots of the electromechanical interface and engage with the plurality of electrical terminals of the battery pack, and further the latch portion engages with the second power tool to maintain a coupling between the electromechanical interface and the second power tool. the electromechanical interface; a plurality of battery cells disposed in the receiving portion of the housing, the battery cells being (1) configured to be connected in parallel with one another to provide power to the plurality of electrical terminals at the first operating voltage when the electro-mechanical interface is coupled to the first power tool, and (2) configured to be connected in series with one another to provide power to the plurality of electrical terminals at the second operating voltage when the electro-mechanical interface is coupled to the second power tool; having the terminal block, the plurality of slots, the plurality of electrical terminals of the battery pack, the longitudinal rail portion, the longitudinal groove portion, and the latch portion of the electromechanical interface have substantially the same configurations as the terminal block, the plurality of slots, the plurality of electrical terminals of the battery pack, the longitudinal rail portion, the longitudinal groove portion, and the latch portion of the electromechanical interface of a battery pack having a single voltage, the battery pack having a single voltage being operable only at the first operating voltage, and being coupled to the first power tool to supply power to the first power tool at the first operating voltage; Power tool system.

25. 25. The power tool system of claim 24, the electromechanical interface of the battery pack having a single voltage is configured to be incapable of being mechanically or electrically coupled to the second power tool; the electro-mechanical interface of the multi-voltage battery pack includes a slot in the housing; the second power tool having a downwardly extending protrusion shaped and configured to mate with a slot in the housing of the multiple voltages battery pack when coupled to the power tool interface of the multiple voltages battery pack; Power tool system.

26. 25. The power tool system of claim 24, The plurality of battery cells of the battery pack having the plurality of voltages are a first battery cell string consisting of five battery cells arranged in series with each other; a second battery cell string consisting of five battery cells arranged in series with each other; and having the first string of battery cells is disposed in a first row within the housing; the second string of battery cells is disposed in a second string within the housing; the second row is disposed above the first row, the first row of battery cells and the second row of battery cells are arranged in a 2 x 5 matrix within the housing; the first row of battery cells and the second row of battery cells each define a longitudinal axis that is parallel to one another; the multi-voltage battery pack having first and second opposing sides; each of the battery cells in the first battery cell string and the second battery cell string has a positive voltage terminal and a negative voltage terminal; positive voltage terminals of three of the five battery cells in the first battery cell string are disposed on the first side of the multiple voltage battery pack; positive voltage terminals of three of the five battery cells in the second battery cell string are disposed on the first side of the multiple voltage battery pack; negative voltage terminals of two of the five battery cells in the first battery cell string are disposed on the first side of the battery pack having multiple voltages; negative voltage terminals of two of the five battery cells in the second battery cell string are disposed on the first side of the multiple voltage battery pack; a negative voltage terminal of the battery cell in the first string of battery cells on the first side is vertically aligned with a corresponding negative voltage terminal of the battery cell in the second string of battery cells on the first side; a positive voltage terminal of the battery cell in the first string of battery cells on the first side is vertically aligned with a corresponding positive voltage terminal of the battery cell in the second string of battery cells on the first side. Power tool system.

27. 25. The power tool system of claim 24, The plurality of battery cells of the battery pack having the plurality of voltages are a first string of battery cells arranged in series with one another; a second string of battery cells arranged in series with each other; and having the plurality of electrical terminals at the electro-mechanical interface of the plurality of voltage battery packs include a first electrical contact and a second electrical contact; the first electrical contact is electrically connected to a first positive voltage terminal of the first string of battery cells; the second electrical contact is electrically connected to a second negative voltage terminal of the second string of battery cells; the first and second electrical contacts are configured to be electrically connected to each other via a conductive jumper of the second power tool when the electro-mechanical interface of the multiple voltage battery pack is coupled to the second power tool, such that the first and second strings of battery cells are electrically connected in series to each other via the conductive jumper when the electro-mechanical interface of the multiple voltage battery pack is coupled to the second power tool. Power tool system.

28. 25. The power tool system of claim 24, The plurality of battery cells of the battery pack having the plurality of voltages are a first string of battery cells arranged in series with one another; a second string of battery cells arranged in series with each other; and having the multiple-voltage battery pack has an open circuit configuration in which the first and second battery cell strings are not electrically connected in parallel or in series to each other; Power tool system.

29. 25. The power tool system of claim 24, The plurality of battery cells of the battery pack having the plurality of voltages are a first string of battery cells arranged in series with one another and having a first positive voltage terminal and a first negative voltage terminal; a second string of battery cells arranged in series with each other and having a second positive voltage terminal and a second negative voltage terminal; having the plurality of electrical terminals of the plurality of voltage battery packs includes a first row of electrical terminals and a second row of electrical terminals; the first column is vertically offset from the second column; a plurality of the electrical terminals in the first row of electrical terminals constitute signal terminals; a plurality of electrical terminals in the second row of electrical terminals defining first and second terminals; the first terminal of the second string of electrical terminals is electrically connected to the first positive voltage terminal of the first string of battery cells; the second terminal of the second string of electrical terminals is electrically connected to the second negative voltage terminal of the second string of battery cells; the first row of electrical terminals being horizontally spaced apart; the second row of electrical terminals being horizontally spaced apart; Power tool system.

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