Soft-start system for power tools with instantaneous switch and mechanical direction selection switch

Abstract

A soft-start system for power tools is described. The soft-start system uses a direction feedback signal from the power tool's direction selection switch. A power tool using this soft-start system is also described. Additionally, a power supply circuit using the soft-start system is described.

Description

[0001] Cross-references to related applications

[0002] This application is a continuation-in-part (CIP) application and claims priority to U.S. Nonprovisional Application No. 16 / 420,383, filed May 23, 2019, which in turn claims priority to U.S. Provisional Application No. 62 / 797,744, filed January 28, 2019. This application also claims priority to U.S. Provisional Patent Application No. 62 / 976,714, filed February 14, 2020. This application also claims priority to Indian Provisional Patent Application No. 202021018474, filed April 30, 2020. Technical Field

[0003] This disclosure relates to the field of power tools, such as tapping machines and drain cleaners. More specifically, this disclosure relates to power supply circuits for power tools, soft-start systems, and power tools using such soft-start systems. Background Technology

[0004] Power tools such as tapping machines are typically powered by a general-purpose motor and use momentary switching, such as a foot switch, and mechanical direction selection switches, such as rotary switches, to control the power flow from AC power to the general-purpose motor. Currently, tapping machines are not equipped with soft-start circuits. In conventional soft-start circuits, a soft-start algorithm is used in conjunction with current feedback and control circuitry on a circuit board.

[0005] However, conventional soft-start circuits are not suitable for tapping machines. This is typically because tapping machines use both momentary switches and mechanical direction switches simultaneously. Furthermore, the circuit boards associated with currently known soft-start circuits cannot be used on different machines or tools, particularly those utilizing controls such as those found in tapping machines. In other words, conventional circuits for traditional soft-start circuits are unsuitable for many, but not all, tapping machines due to their specific control configurations. Another drawback of conventional soft-start circuits is that, without directional feedback, a HOT start may occur if the user operates the machine while the momentary switch is blocked, which is unacceptable according to IEC 62481 and IEC 61000:3-3 standards.

[0006] Another issue associated with tapping machines equipped with both instantaneous and mechanical direction switches is controlling the power supply to the machine, particularly the motor's armature windings, via both switches. More specifically, the tapping machine cannot be turned on unless both switches are closed. Therefore, determining the position of the mechanical direction switch is essential, and this information is used to control the soft-start algorithm.

[0007] Therefore, a soft-start circuit and related devices for power tools with instantaneous switching and mechanical direction selection switches are needed to mitigate the above-mentioned disadvantages. Summary of the Invention

[0008] The difficulties and drawbacks associated with previous methods are addressed in this disclosure as follows:

[0009] In one aspect, this disclosure provides a power supply circuit including a momentary switch, a direction selection switch, a soft-start system, and at least one direction feedback signal from the direction selection switch to the soft-start system.

[0010] In another aspect, this disclosure provides a soft-start system including a momentary switch for switching power supplies. The momentary switch provides a momentary switch actuation signal. The soft-start system also includes a zero-crossing detection device for providing a zero-crossing detection input AC supply. The soft-start system also includes a driver for switching and controlling the power supplies. The driver has an input for receiving a driver control signal. The soft-start system also includes a direction selection switch for switching the direction of motor rotation. The direction selection switch provides a positive signal and a reverse signal. The soft-start system also includes a microcontroller for executing a soft-start algorithm. The microcontroller receives the momentary switch actuation signal, the zero-crossing detection signal, the positive signal, or the reverse signal. The microcontroller is configured to generate a driver control signal using the soft-start algorithm. The driver control signal is provided to the driver's input.

[0011] In another aspect, this disclosure provides an electric tool including an electric motor that provides rotational output, an instantaneous switch for switching power to the motor, a direction selection switch for switching the rotational direction of the motor to the direction of the motor, and a soft-start system for controlling the operation of the electric motor.

[0012] In another aspect, this disclosure provides a power tool including an electric motor providing rotational output and a soft-start system for controlling the operation of the electric motor. The soft-start system includes (i) an instantaneous switch for switching power, the instantaneous switch providing an instantaneous switch actuation signal, (ii) a zero-crossing detection device for providing a zero-crossing detection signal, (iii) a driver for switching and controlling the power, the driver having an input for receiving a driver control signal, (iv) a direction selection switch for switching the rotational direction of the motor, the direction selection switch providing a forward signal and a reverse signal, and (v) a microcontroller for executing a soft-start algorithm. The microcontroller receives the instantaneous switch actuation signal, the zero-crossing detection signal, the forward signal, and the reverse signal. The microcontroller is configured to generate a driver control signal using the soft-start algorithm. The driver control signal is provided to the input of the driver.

[0013] As will be appreciated, the subject matter described herein is capable of other and different embodiments, and modifications can be made to several details in various respects without departing from the claimed subject matter. Therefore, the drawings and description should be considered illustrative rather than restrictive. Attached Figure Description

[0014] Figure 1 A schematic block diagram of the power supply circuit in a conventional tapping machine is shown.

[0015] Figure 2 The internal structure of the direction selection switch is shown.

[0016] Figure 3 The electrical connections of the directional switch in the forward (FWD) position are shown.

[0017] Figure 4 The electrical connections of the directional switch in the reverse (REV) position are shown.

[0018] Figure 5 The direction of the current flowing through the armature winding in the motor of the tapping machine is shown, as well as the direction switch in the forward (FWD) position.

[0019] Figure 6 The diagram illustrates the change in the direction of the current flowing through the armature windings in the motor and the direction switch in reverse (REV).

[0020] Figure 7 A schematic block diagram of a power supply circuit according to an embodiment of the present disclosure is shown, the power supply circuit having a soft-start circuit board embedded in a power tool.

[0021] Figure 8 A schematic block diagram of a soft-start system, soft-start circuit, or soft-start board according to an embodiment of the present disclosure is shown.

[0022] Figure 9 A schematic diagram of a power supply and converter used in conjunction with a soft-start circuit is shown.

[0023] Figure 10 The instantaneous switch detection circuit and the zero-crossing detection circuit are shown.

[0024] Figure 11 The direction detection circuit and associated waveforms are shown.

[0025] Figure 12 The waveform conditions for a microcontroller’s repeated soft-start routine or algorithm are shown.

[0026] Figure 13 The waveforms associated with the undesirable HOT start-up conditions are shown.

[0027] Figure 14 The modified directional feedback circuit is shown.

[0028] Figure 15 The waveform of the modified direction detection is shown.

[0029] Figure 16 The waveform of the TRIAC gate pulse is shown.

[0030] Figure 17 The waveform of the modified directional feedback is shown.

[0031] Figure 18 The waveform of soft start is shown.

[0032] Figure 19 An alternative embodiment of the power tool system is shown, in which soft start is utilized, but the direction of motor rotation is changed electronically.

[0033] Figure 20 This is a flowchart illustrating a method for powering a tool according to this topic.

[0034] Figure 21 This is a flowchart illustrating how to operate the tools according to this topic. Detailed Implementation

[0035] Some of the objectives of this disclosure achieved by at least one embodiment herein are as follows:

[0036] The purpose of this invention is to provide a soft start for power tools, the power tools having an instantaneous switch and a mechanical direction selection switch.

[0037] Another object of the present invention is to provide a soft start for a power tool having an instantaneous switch and a mechanical direction selection switch, which facilitates direction detection.

[0038] Another object of the present invention is to provide a soft start for a power tool having an instantaneous switch and a mechanical direction selection switch, which facilitates soft start without the need for a current sensor.

[0039] Another object of the present invention is to provide a soft start for a power tool having an instantaneous switch and a mechanical direction selection switch, and to provide a solution and a solution to problems associated with tapping machines including instantaneous switches and direction switches.

[0040] Another object of the present invention is to provide a soft start for a power tool having an instantaneous switch and a mechanical direction selection switch, and capable of operating a tapping machine with a power range of 0.5 HP to 3 HP.

[0041] Power tools such as tapping machines with momentary switches and mechanical direction selection switches typically include multiple switch positions or combinations of positions to control the power flow from AC power or a power supply to the power tool's motor. Typically, the momentary switch and the mechanical direction selection switch are connected in series, so the motor cannot be turned on unless both are switched on.

[0042] As used in this article, “soft start” refers to the characteristic of an electric motor gradually transitioning to the typical or desired rotational output speed associated with the operation of a power tool. For example, this gradual transition typically occurs when the electric motor is activated and, over a period of 0 ms to 800 ms, the motor’s rotational output increases from 0 RPM to a speed of approximately 18,100 RPM.

[0043] Figure 1 A schematic block diagram of the power supply circuit in a conventional tapping machine is shown. This type of tapping machine is typically equipped with a universal motor having an excitation winding and an armature winding. The direction of the motor is reversed by changing the direction of the current flowing through the armature winding. Specifically, Figure 1 A momentary switch 105 is shown, which, as previously described, can be in the form of a foot switch. Figure 1 A suppressor 110 is also shown, which can be, for example, a surge protector that limits the voltage supplied to the motor and / or other electrical components. The suppressor or surge protector prevents voltage spikes. Figure 1 A mechanical direction selection switch 120, or as occasionally referred to herein as a "direction switch" or "direction switch," is also shown. A suppressor 110 is disposed between the instantaneous switch 105 and the mechanical direction switch 120 and is electrically connected to both the instantaneous switch and the mechanical direction switch. Figure 1 Motor 170 is also shown. A mechanical direction selection switch 120 is disposed between the suppressor 110 and the motor 170 and is electrically connected to the suppressor and the motor. As is known in the art, motor 170 includes a field winding 171 and an armature winding 172.

[0044] For example, the mechanical direction switch of switch 120 is used to change the rotation direction of the motor from forward (FRD) to reverse (REV). Figure 2 The internal schematic structure of the direction switch 120 is shown. Figure 3 This is a detailed view of a portion of the internal schematic structure of the directional switch 120, showing representative contacts of the motor 170 rotating in the FRD direction and their number (position 1). Figure 4 This is a detailed view of a portion of the internal schematic structure of the direction switch 120, showing representative contacts of the motor 170 rotating in the REV direction and their numbering (position 2). From Figure 2 As can be seen, switch contacts 8-6, 7-3, 4-2, and 5-1 are always electrically connected or "short-circuited." For example... Figure 3 As shown, when the direction switch 120 is in the FRD direction, it is the same as described above. Figure 2 Like the contacts, contacts 12-11, 6-5, and 4-3 are also short-circuited. However, as... Figure 4 As shown, when the direction switch 120 is in the REV direction, it is the same as described above. Figure 2 Like the contacts, contacts 12-11, 8-7, and 1-2 are also short-circuited. Once the momentary switch 105 is pressed or otherwise actuated, an AC input voltage is available at the inputs of contacts 12 and 8 of the FRD / REV mechanical direction selection switch 120. If the mechanical direction selection switch 120 is in the FRD direction, the current flowing through the armature winding follows the direction shown in the diagram. Figure 5 As shown. If the mechanical direction selection switch 120 is in the REV direction, the direction of the current flowing through the armature winding will become as follows. Figure 6 As shown.

[0045] Compare Figure 5 and Figure 6 It can be seen that the direction of the armature winding voltage changes relative to the position of, for example, the mechanical direction selection switch of switch 120. Therefore, if the armature voltage can be properly sensed, the operating direction of the motor can be detected.

[0046] A preferred embodiment of the soft-start system according to the invention for a power tool having, for example, a foot switch 105 as an instantaneous switch and, for example, a switch 120 as a mechanical direction selection switch will now be described in detail with reference to the figures.

[0047] Figure 7 A schematic block diagram of a power supply circuit including a soft-start system, soft-start circuit, or soft-start board 115 according to an embodiment of this disclosure is shown. As described herein, the power supply circuit is used in a power tool 250. The soft-start system, soft-start circuit, or soft-start board 115 is disposed between the suppressor 110 and the mechanical direction selection switch 120, and one or more direction feedback signals 210, 212 provided to the soft-start board 115 avoid the aforementioned HOT start problem. Further reference Figure 7 Suppressor 110 is located at the input side of the soft-start system, soft-start circuit, or soft-start board 115. A positive feedback signal 210 is provided to the soft-start system 115 from the direction selection switch 120. A negative feedback signal 212 is provided to the soft-start system 115 from the direction selection switch 120.

[0048] Various switches can be used in this disclosure. Although directional selection switches are described herein as mechanical, i.e., having physical components such as contacts, terminals, and / or throw or movable switch elements, it should be understood that this disclosure also includes the use of motor switches and electronic switches. The directional switches used in this disclosure are multi-position switches and typically provide selection of a first position, a second position, a third position, and in many versions, a fourth position or additional position. In many embodiments, the directional switch can provide two, three, four, or more positions. The switch positions are typically associated with the operating mode of the motor, tool, or machine, such as forward, reverse, and neutral. A wide variety of momentary switches can be used.

[0049] Figure 8 A schematic block diagram of a soft-start system, soft-start circuit, or soft-start board 115 according to this disclosure is shown. (Refer to...) Figure 8 In one embodiment, when the momentary switch 105 (e.g.) Figure 7 When the soft-start system 115 (shown) is pressed or otherwise actuated, an AC power supply voltage is available at the input of the non-isolated power supply 150. The non-isolated power supply 150 generates a DC voltage, which is applied to the input of the isolated DC-DC converter 155 to power all the digital circuitry of the system 115. Typically, the power supply 150 is an AC-DC transformer, and the converter 155 is a buck converter that reduces the DC voltage applied to its input to a DC output voltage typically between 5 volts and 3.3 volts. The system 115 typically includes momentary / foot switch detection circuitry or other device 130, zero-crossing detection (ZCD) circuitry or other device 135, one or more TRIAC drivers 140, forward detection circuitry or device 165, reverse detection circuitry or device 175, signal conditioning circuitry or device 180, and a microcontroller 185. In some versions, the soft-start system 115 may further include the non-isolated power supply 150 and the isolated DC-DC converter 155. The soft start system 115 receives electrical power from an AC power source or line 125 and an associated neutral point (NEUTRAL) 145. The soft start system 115 is electrically connected to the FRD / REV directional switch 160 (similar or identical to the previously mentioned directional switch 120), and in turn to the motor 170.

[0050] Figure 9 A schematic diagram of a typical power supply 150 and converter 155 used in the soft-start circuit 115 is shown. On-board circuitry detects the momentary switch 105. Figure 7 The press or actuation of ) and sends a signal to the microcontroller 185 ( Figure 8 The soft-start circuit or board 115 also detects the "zero crossing" of the AC power signal and generates one or more pulses 220. Figure 8These pulses 220 are fed back to the microcontroller 185 to identify the frequency of the input signal. The instantaneous switch detection 130, together with the zero-crossing detection (ZCD) 135, provides input to the microcontroller 185 to initiate or otherwise start a soft-start routine or algorithm.

[0051] Figure 10 The instantaneous switch detection 130 and zero-crossing detection (ZCD) circuit 135 are shown. Motor direction is detected based on armature voltage; therefore, to obtain feedback, a voltage must exist across the armature terminals, and only when the mechanical direction selection switch 120 (…) is activated. Figure 7 This is only possible when the mechanical direction selection switch 120 is in the FRD or REV position. If the mechanical direction selection switch 120 is in another position, such as zero or "0" or "OFF", there will be no voltage across the armature, and therefore no direction feedback will be obtained. Under standard operating conditions, when the user places the mechanical direction selection switch 120 in the ON position and then presses the momentary switch 105, the soft-start routine is initiated or otherwise applied, and the motor gradually turns on.

[0052] Figure 11 The orientation detection circuits 165 and 175, along with their associated waveforms, are shown. Figure 11 It can be seen that the directional feedback gradually increases with the increase of armature voltage. The direction detection circuits 165 and 175 require approximately 280ms to provide recorded feedback to the microcontroller 185. When the user has blocked the momentary switch 105 but the mechanical direction selection switch 120 is in the 0 position, the onboard microcontroller 185 will receive signals from the momentary switch 105 and the zero-crossing detector (ZCD) 135, and therefore the controller 185 will initiate a soft-start routine. However, since the mechanical direction selection switch 120 is in the 0 position, there will be no voltage across the armature, therefore there will be no directional feedback, and thus the soft-start routine will be stopped, and as... Figure 12 As shown, the microcontroller 185 will restart the routine. This causes the soft-start routine or algorithm to loop or repeat. Since the onboard controller 185 cannot control when the user opens the direction switch 120, this situation may lead to... Figure 13 The waveform shows the undesirable HOT startup conditions.

[0053] More specifically, in some embodiments, a voltage measurement on a rotary switch is used to monitor forward and reverse directions. This measurement (e.g.) Figure 11 (As shown) The switch selection (forward or reverse) is identified by measuring the voltage across the armature winding. This circuit exhibits hysteresis; if the user blocks the momentary switch 105 (not recommended, but likely to occur in the field), the soft-start function may be lost. To avoid this loss of soft-start function, a... Figure 14The circuit.

[0054] Figure 13 The diagram illustrates the different times at which the user can open the direction switch 120 to the FRD / REV position, and based on the motor voltage at that moment, the motor 170 draws an equivalent current. This results in a HOT start. Therefore, to remedy this situation, according to this topic, it is considered necessary to improve the response time of the direction feedback and apply a constant voltage to the motor armature. This has been found to avoid hysteresis in the motor 170 and sudden starts or "jumps".

[0055] Figure 14 The modified directional feedback circuits 165A and 175A according to this disclosure are shown. Directional feedback outputs 210 and 212 are provided to the onboard microcontroller 185, and signals are sent to the microcontroller 185 based on this feedback and several other feedbacks to perform a soft-start function. Figure 14 The circuitry ensures that the timing of the circuit is fast enough to prevent HOT startup. IS01 / IS02 provides isolation from the AC power supply voltage present on the mechanical direction switch / armature winding. Furthermore, IS01 / IS02 converts the AC power supply to a low-level DC voltage (e.g., 0 to 3VDC), which is then conditioned by additional signal conditioning circuitry before being supplied to the microcontroller 185. Figure 8 The 180 in the middle processes the low-level voltage. Figure 14 The circuitry allows for early direction detection, specifically at low motor current. This circuitry includes an operational amplifier that detects the direction of the rotary switch (i.e., the direction switch) at very low armature voltage levels and therefore low armature current, and transmits this information to the microcontroller 185. This circuitry allows an AC voltage to appear across the rotary switch for a very short time (e.g., a fixed duty cycle), which does not cause a "sudden" or hysteretic response in the motor 170. This AC voltage is applied to the armature windings of the motor 170 when the user changes the rotary switch to the FRD or REV position. Figure 14 The circuitry senses the low voltage and, within 100ms, provides a signal to the onboard microcontroller 185 to execute a soft-start routine, which is imperceptible to the user. This operation makes the entire circuit unique, especially when operating a tapping machine with the aforementioned instantaneous switch 105 and mechanical direction switch 120.

[0056] Figure 15 The modified direction detection waveform is shown. Because the detection level is reduced, a full soft-start routine is no longer required for direction detection. An optimal TRIAC duty cycle has been determined that avoids the aforementioned hysteresis and / or abrupt changes in the motor, and that this duty cycle can be continuously applied to motor 170 regardless of the position of the mechanical direction selection switch. Figure 16 As shown in the waveform, the TRIAC gate pulse dips along with the zero-crossing detection signal. The modified direction feedback waveform is as follows. Figure 17 As shown.

[0057] The waveform was evaluated under the condition that the momentary switch 105 was blocked and the mechanical direction selection switch 120 was turned on / off. For example... Figure 18 As shown in the waveform, a soft start is observed every time the machine is turned on, regardless of whether the machine is operated incorrectly.

[0058] In many embodiments, the purpose of this disclosure is to provide orientation detection and soft-start without a current sensor. Therefore, since voltage sensors typically have a longer lifespan than current sensors, the reliability, cost, and size of the resulting system are improved.

[0059] Furthermore, this disclosure provides a solution for a tapping machine having, for example, an instantaneous switch 105 and a directional switch 120. This solution is applicable to tapping machines, particularly those with a power range of 0.5 HP to 3 HP. It should be understood that this disclosure is also applicable to power tools with power less than 0.5 HP and / or greater than 3 HP.

[0060] In an alternative embodiment, a similar solution can be implemented for power tools, where soft starting is essential, but the direction of rotation is changed electronically, i.e., there is no mechanical switch, such as by pressing a button on a panel or other component. This system can be implemented using a combination of relays that can be used to change the direction of current flowing through the motor armature based on received electronic signals. Figure 19 A schematic block diagram of this configuration is shown. The relay can be mounted externally on a panel or, for example, on an electronic control board integrated into a power tool. Specifically, Figure 19Another embodiment of the circuitry for a power tool using a soft-start system is shown, wherein the direction of rotation of the motor is electronically changed. An AC power supply or line 125 and an associated neutral point 145 are provided at an instantaneous switch 105. The output of switch 105 is electrically connected to an electronic control board 195. The electronic control board 195 typically includes a microcontroller and other circuitry described herein. The electronic control board 195 receives actuation signals from a push-button, toggle switch, or rocket switch 200. The AC power supply and neutral points 125, 145 provide electrical power to the motor 170. Two relays RL1 and RL2, each having a coil 205, are electrically connected to the field winding and armature winding 172, respectively. The electronic control board 195 receives an armature voltage measurement signal, which it uses to determine the direction of rotation of the motor 170. For example, the electronic control board 195 can energize relays RL1 and RL2 and associated coils 205 to change the direction of the current flowing through the armature winding 172 of the motor 170 based on armature voltage measurement signals or other parameters.

[0061] The soft-start system and related aspects disclosed herein can be combined with and / or used with a wide variety of power tools, such as Figure 7 The power tool 250 is schematically shown in the diagram. Almost all power tools that use motors, momentary switches, and directional switches can be used in conjunction with the contents of this disclosure. Non-limiting examples of such power tools include tapping machines, drain cleaners, hand drills, impact wrenches, lathes, etc.

[0062] Typically, in one embodiment, a power tool includes an electric motor providing rotational output, an instantaneous switch for switching power to the motor, a direction selection switch for switching the rotational direction of the motor, and a soft-start system for controlling the operation of the electric motor. In some versions, the power tool may include a suppressor disposed on the input side of the soft-start system. The power tool may include at least one directional feedback signal from the direction selection switch or other circuitry to the soft-start system. The power tool may include a positive signal from the direction selection switch or other circuitry to the soft-start system. Optionally or additionally, the power tool may include a reverse signal from the direction selection switch or other circuitry to the soft-start system. The soft-start system may include (i) a zero-crossing detection device for providing a zero-crossing detection signal, (ii) a driver for switching and controlling power, the driver having an input for receiving a driver control signal, and (iii) a microcontroller for executing a soft-start algorithm. The instantaneous switch or other circuitry provides an instantaneous switch actuation signal. The direction selection switch or circuitry provides both a positive and a reverse signal. The microcontroller receives the instantaneous switch actuation signal, the zero-crossing detection signal, the positive signal, and the reverse signal. The microcontroller is configured to use a soft-start algorithm to generate driver control signals. These driver control signals are provided to the driver's input. In some versions, the direction selection switch is a mechanical direction selection switch. In other versions, the direction selection switch is an electronic direction selection switch.

[0063] In another embodiment, the power tool includes an electric motor providing rotational output and a soft-start system for controlling the operation of the electric motor. The soft-start system includes (i) an instantaneous switch for switching power, the instantaneous switch or other circuitry providing an instantaneous switch actuation signal, (ii) a zero-crossing detection device for providing a zero-crossing detection signal, (iii) a driver for switching and controlling power, the driver having an input for receiving driver control signals, (iv) a direction selection switch for switching the direction of motor rotation, the direction selection switch or other circuitry providing circuitry for positive and negative signals, and (v) a microcontroller for executing a soft-start algorithm. The microcontroller receives the instantaneous switch actuation signal, the zero-crossing detection signal, the positive signal, and the negative signal. The microcontroller is configured to generate driver control signals using the soft-start algorithm. The driver control signals are provided to the driver's input. In some versions, the soft-start system does not have a current sensor. The direction selection switch may be a mechanical direction selection switch. Alternatively, the direction selection switch may be an electronic direction selection switch.

[0064] Figure 20A method 300 for powering a tool or tool system according to this subject matter is illustrated. Method 300 includes actuating a power switch or startup routine associated with the tool or tool system as shown in operation 305. In operation 310, system power is turned on, which may be indicated to the user, for example, via an indicator or light. In operation 320, a clock and / or controller in the tool system is activated; in some applications, the clock and / or controller may include a reset. In operation 330, general purpose input / output (GPIO) controls associated with the tool or tool system are activated and / or otherwise configured. For example, this may include configuring pins as inputs or outputs depending on the type of circuit to which the controller pins are connected. GPIO pins can be configured as inputs to detect direction feedback, and GPIO pins can also be configured as outputs to generate gate pulses to enable TRIAC. In operation 340, peripheral components are configured. For example, this may include configuring timers required for timing calculations within a microcontroller, and configuring microcontroller pins as communication channels (e.g., UART or I2C). In operation 350, system variables are initialized. This may include initializing some default variables, such as zero-crossing detection dejitter delay and default input frequency, as well as the fixed gate pulse width, which needs to be applied to the TRIAC before receiving direction feedback. In operation 360, the application's main loop begins. Now combined Figure 21 Describe the process. In operation 370, method 300 terminates. Termination may be due to operator actions and / or other operational aspects.

[0065] Figure 21 It illustrates the use of tools or tool systems to perform, for example... Figure 20The main loop of the application referenced in this document is method 400. Method 400 includes an initial permission phase as shown in 405. If permitted, the state of a switch, such as a foot switch 410, is evaluated in operation 410. If the switch in operation 410 is actuated, the method proceeds to operation 415, where a frequency is detected. If the switch in operation 410 is not actuated, as shown herein, the method proceeds to loop phase 455. In operation 415, if a frequency is detected, as shown herein, the method proceeds to the phase immediately preceding operation 425. In operation 415, if no frequency is detected, operation 420 is performed, where the power supply frequency is monitored, referred to as zero-crossing detection. In operation 425, a fixed gate pulse is applied to one or more TRIACs. In operation 430, if a forward or reverse direction is detected, as shown herein, the method proceeds to operation 435. In operation 430, if neither a forward nor reverse direction is detected, the method again executes operation 425. In operation 435, a soft start is applied to the motor. In stage 440, the motor is running. In operation 445, if the foot switch or other actuator is de-actuated, or if the direction changes, the motor stops in operation 450. If the foot switch or other actuator remains stationary and the direction remains unchanged, the motor continues to operate as in 440. After the motor stops in operation 450, the method reaches cycle stage 455, in which the method is repeated starting from 405.

[0066] This disclosure provides several technical advantages, including, but not limited to, enabling soft-start of power tools with instantaneous switches and mechanical direction selection switches. As mentioned above, in some versions, power tools can use electronic direction selection switches. These advantages include, but are not limited to, facilitating the presence of direction detection, facilitating soft-start without current sensors, providing a universal solution for tapping machines including instantaneous switches and direction switches, and / or enabling use in tapping machines operating at power from 0.5 HP to 3 HP.

[0067] Examples are provided to thoroughly convey the scope of this disclosure to those skilled in the art. Numerous details relating to particular components and methods are set forth to provide a complete understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that the details provided in the examples should not be construed as limiting the scope of this disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

[0068] In this disclosure, the terminology used is for the purpose of explaining particular embodiments only, and such terminology should not be considered as limiting the scope of this disclosure. As used in this disclosure, unless the context clearly indicates otherwise, the forms “a,” “an,” and “the” are also intended to include plural forms. The terms “comprises,” “comprising,” “including,” and “having” are open-ended transitional phrases that specify the presence of the stated features, elements, modules, units, and / or components, but do not preclude the presence or inclusion of one or more other features, elements, components, and / or groups thereof.

[0069] When an element is referred to as being “mounted,” “joined,” “connected,” or “coupled” to another element, it can be located directly on, joined, connected to, or coupled to that other element. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed elements.

[0070] Terms such as “internal”, “external”, “below”, “under”, “lower”, “above”, “upper”, etc., may be used in this disclosure to describe the relationship between the different elements shown in the figures.

[0071] The use of the terms "at least" or "at least one" implies the use of one or more elements or components or quantities, as they may be used in embodiments of this disclosure to achieve one or more desired purposes or results.

[0072] The foregoing description of embodiments has been provided for illustrative purposes and is not intended to limit the scope of this disclosure. Components of a particular embodiment are generally not limited to that particular embodiment and are interchangeable. Such variations are not considered to depart from this disclosure, and all such modifications are considered to be within the scope of this disclosure.

[0073] In the following description, embodiments thereof and their various features and advantageous details are illustrated with reference to non-limiting examples. Descriptions of well-known components and processing techniques have been omitted to avoid unnecessarily obscuring the embodiments herein. The examples used herein are intended only to facilitate an understanding of how the embodiments herein can be practiced, and further to enable those skilled in the art to practice the embodiments herein. Therefore, the examples should not be construed as limiting the scope of the embodiments herein.

[0074] The foregoing description of specific embodiments sufficiently reveals the general nature of the embodiments herein. Therefore, others can readily modify and / or adapt various applications such as the specific embodiments by applying existing knowledge without departing from the general concept. Thus, such modifications and adaptations should and are intended to be understood as being within the equivalent meaning and scope of the disclosed embodiments. It should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered restrictive. Therefore, although embodiments herein have been described with reference to preferred embodiments, those skilled in the art will recognize that modifications can be made within the spirit and scope of the embodiments described herein to practice the embodiments.

[0075] Any discussion of documents, actions, materials, devices, articles, etc., included in this specification is only for providing context for this disclosure. It should not be construed as an admission that any or all of these issues constitute part of the prior art, or as an admission that they were common general knowledge in the relevant field that existed anywhere prior to the priority date of this application.

[0076] Although the focus herein has been placed on the components and elements of the preferred embodiments, it should be understood that many embodiments can be implemented and many changes can be made to the preferred embodiments without departing from the principles of this disclosure. Based on the disclosure herein, those skilled in the art will appreciate these and other variations in the preferred embodiments and other embodiments of this disclosure, and it will be clearly understood that the foregoing description should be interpreted as illustrative rather than limiting.

[0077] As the technology is applied and improved in the future, many other benefits will undoubtedly become apparent.

[0078] All patents, applications, standards and articles mentioned in this article are incorporated herein by reference in their entirety.

[0079] This subject matter encompasses all possible combinations of the features and aspects described herein. Therefore, for example, if one feature is described in association with one embodiment and another feature is described in association with another embodiment, it should be understood that this subject matter includes embodiments having combinations of these features.

[0080] As described above, this subject matter addresses many problems associated with prior strategies, systems, and / or devices. However, it should be understood that, without departing from the principles and scope of the claimed subject matter as set forth in the appended claims, those skilled in the art can make various changes to the details, materials, and arrangements of the components described and illustrated herein for the purpose of explaining the nature of this subject matter.

Claims

1. A power supply circuit for a general-purpose motor, the power supply circuit comprising: Instantaneous switch; Direction selection switch; Soft-start system; At least one directional feedback signal from the direction selection switch to the soft-start system; The direction selection switch includes a first state for the universal motor to reverse, a second state for the universal motor to not rotate, and a third state for the universal motor to rotate forward. The direction selection switch is configured to change the rotation direction of the general-purpose motor, and the instantaneous switch includes a first state for actuation and a second state for de-actuation. Furthermore, the direction selection switch and the momentary switch are configured such that: if the momentary switch is in a first state for actuation and the direction selection switch is in a third state for the general-purpose motor to rotate forward, then the general-purpose motor operates in the forward direction, or If the instantaneous switch is in the first state for actuation and the direction selection switch is in the first state for reversing the universal motor, then the universal motor runs in reverse.

2. The power supply circuit according to claim 1, wherein, The at least one direction feedback signal includes a reverse signal from the direction selection switch to the soft-start system.

3. The power supply circuit according to claim 1, wherein, The soft-start system includes (i) a zero-crossing detection device that provides a zero-crossing detection signal, (ii) a driver for switching and controlling the power supply, the driver having an input for receiving driver control signals, and (iii) a microcontroller for executing a soft-start algorithm. The instantaneous switch provides an instantaneous switch actuation signal; The direction selection switch provides a positive signal and a reverse signal; The microcontroller receives the instantaneous switch actuation signal, the zero-crossing detection signal, the positive signal, and the negative signal. The microcontroller is configured to generate a driver control signal using the soft-start algorithm, and the driver control signal is provided to the input of the driver.

4. The power supply circuit according to claim 3, wherein, The driver is a TRIAC driver.

5. The power supply circuit according to claim 3, wherein, The soft-start system does not have a current sensor.

6. The power supply circuit according to claim 1, wherein, The direction selection switch is a mechanical direction selection switch.

7. The power supply circuit according to claim 1, wherein, The at least one direction feedback signal is provided by the direction detection circuit.

8. The power supply circuit according to claim 7, wherein, The direction detection circuit includes a forward detection circuit and a reverse detection circuit.

9. The power supply circuit according to claim 8, wherein, The forward detection circuit and the reverse detection circuit detect the rotation direction of the general-purpose motor.

10. The power supply circuit according to claim 1, wherein, The direction selection switch directly controls the rotation direction of the general-purpose motor.

11. The power supply circuit according to claim 1, wherein, The direction selection switch does not communicate directly with the microcontroller, which is configured to generate driver control signals.

12. The power supply circuit according to claim 1, wherein, The soft-start system detects the rotation direction of the general-purpose motor.

13. The power supply circuit according to claim 1, wherein, The power supply circuit is configured to activate the soft-start system when the instantaneous switch is actuated and the state of the direction selection switch changes.

14. The power supply circuit according to claim 13, wherein, The state change of the direction selection switch includes changing between the off state and the forward or reverse state.

15. A soft-start system for a general-purpose motor, the system comprising: A momentary switch for switching power, the momentary switch including a first state for actuation, the momentary switch providing a momentary switch actuation signal; A zero-crossing detection device, which is used to provide a zero-crossing detection signal; A driver for switching and controlling power, the driver having an input for receiving driver control signals; A direction selection switch, used to switch the power supply, provides a positive signal and a reverse signal, and A microcontroller for executing a soft-start algorithm, the microcontroller receiving an instantaneous switch actuation signal, a zero-crossing detection signal, a positive signal, and a negative signal, the microcontroller being configured to use the soft-start algorithm to generate a driver control signal, the driver control signal being provided to the input of the driver; The direction selection switch and the instantaneous switch are configured such that if the instantaneous switch is in a first state for actuation and the direction selection switch provides a positive signal, the general-purpose motor operates in the forward direction.

16. The soft-start system according to claim 15, wherein, The driver is a TRIAC driver.

17. The soft-start system according to claim 15, wherein, The soft-start system does not have a current sensor.

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