HANDHELD BATTERY OPERATED POWER TOOL, RECHARGEABLE BATTERY PACK, AND METHODS FOR CONTROLLING SUCH POWER TOOLS AND BATTERY PACKS - Patent application

Abstract

The handheld battery operated power tool includes a work implement, an electric motor configured to operate the work implement, and a connector assembly (32) configured to be releasably coupled to a mating connector of a removable and rechargeable battery pack (20) to power the electric motor. The connector assembly (32) includes a connector temperature sensing device (58) configured to sense a temperature of the connector assembly (32). A rubber cushion (48) allows the connector body (34) to flex relative to the housing (13a).

Description

[Technical field]

[0001] The present invention relates to hand-held battery operated power tools, rechargeable battery packs, combinations of such power tools and battery packs and systems including the same, as well as to methods of controlling such power tools and battery packs, and computer programs for implementing such methods. [Background technology]

[0002] Hand-held power tools such as chainsaws have been well known for over 100 years. Considering power to weight and operating time, most chainsaws are still powered by internal combustion engines of the two-stroke type, but battery-powered chainsaws are becoming more popular. However, obtaining high power without compromising other aspects of the chainsaw such as cost, weight, battery life before recharging, and the usefulness of the battery for other types of products remains a challenge. Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to solve or at least mitigate some or all of the above mentioned problems. [Means for solving the problem]

[0004] To this end, a hand-held battery-operated power tool is provided. The hand-held battery-operated power tool includes a work implement, an electric motor configured to operate the work implement, and a connector assembly configured to be releasably coupled to a mating connector of a removable and rechargeable battery pack to power the electric motor. The connector assembly includes a connector temperature sensing device configured to sense a temperature of the connector assembly. The connector temperature sensing device can monitor the actual condition of the connector assembly, thereby allowing a higher current to be obtained from the battery pack, at least temporarily, than would be possible without the connector temperature sensing device. For example, the use of lithium-ion cells in the battery pack may allow a relatively wide operating voltage, for example, from about 25V to about 42V, in a power tool system specified to operate at 36V, depending on the state of charge of the battery pack. Such a wide voltage range may require increased current during discharge of the battery pack as the voltage decreases in order to maintain a certain output of the power tool. This generates more heat in the connector assembly. Monitoring the temperature of the connector assembly allows the average power of the power tool to be increased during a discharge cycle of the battery pack. The connector temperature sensing device may include one or more temperature sensors, which may be configured as, for example, thermistor(s), for example, of a negative temperature coefficient type. According to an embodiment, the power tool may be configured to obtain a maximum power of more than 1.8 kW from the battery pack. For example, the power tool may be an outdoor power tool, for example, a leaf blower, or a vegetation cutter, such as a chainsaw or a clearing saw, or a construction tool, for example, a power cutter / cut-off machine for cutting bricks, metal, and concrete. The power tool may include a battery compartment configured to accommodate and hold the battery pack.

[0005] According to a second aspect, at least some of the above-mentioned problems are solved or at least alleviated by a rechargeable battery pack. The rechargeable battery pack is configured to be removably attached to a hand-held battery-operated power tool. The rechargeable battery pack comprises a plurality of rechargeable battery cells and a connector assembly configured to be releasably coupled to a mating connector of the power tool to supply power to the power tool from the plurality of battery cells. The connector assembly comprises a connector temperature sensing device configured to sense a temperature of the connector assembly. The plurality of rechargeable battery cells may be electrically interconnected in groups, for example in a series and / or parallel configuration. The plurality of battery cells may be arranged within a battery housing. The connector assembly may comprise a set of current supply connector terminals arranged to be accessible from outside the battery pack. The rechargeable battery cells may be, for example, of the lithium-ion type. According to an embodiment, the connector temperature sensing device may be arranged at a certain distance from the rechargeable battery cells. This reduces heat transfer from the rechargeable battery cells to the connector temperature sensing device. The distance between the connector temperature sensing device and the nearest battery cell is preferably greater than 30 mm. Again, the connector temperature sensing device may include one or more temperature sensors, which may be configured as, for example, thermistor(s), for example, of the negative temperature coefficient type. The battery pack may be configured to provide a maximum power of greater than 1.8 kW to the power tool.

[0006] According to an embodiment of the hand-held battery-operated power tool and / or the battery pack, the connector assembly may comprise a first current supply connector terminal configured to engage with a respective mating first current supply connector of the mating connector at a first terminal engagement connection. The connector temperature sensing device comprises a first terminal temperature sensor located less than 60 mm from the first terminal engagement connection. The first terminal temperature sensor may be located within said distance along a path of the first current supply line, which may be formed at least in part by, for example, the first current supply cable. According to a further embodiment, the first terminal temperature sensor may be located less than 40 mm from the first terminal engagement connection.

[0007] According to an embodiment, the connector assembly may include a first current supply cable. The first terminal temperature sensor is disposed less than 8 mm from a conductor of the first current supply cable. The first current supply cable may be coupled to the first current supply connector terminal. According to a further embodiment, the first terminal temperature sensor may be disposed in direct contact with the first current supply cable.

[0008] According to an embodiment, the connector assembly may include a second current supply connector terminal. The second current supply connector terminal is configured to engage with a respective mating second current supply connector terminal of the mating connector at the second terminal engagement connection. The connector temperature sensing device includes a second terminal temperature sensor located less than 60 mm from the second terminal engagement connection. According to a further embodiment, the second terminal temperature sensor may be located less than 40 mm from the second terminal engagement connection. The first current supply connector terminal may be a positive voltage current supply connector terminal and the second current supply connector terminal may be a negative voltage current supply connector terminal. Alternatively, the first current supply connector terminal may be a negative voltage current supply connector terminal and the second current supply connector terminal may be a positive voltage current supply connector terminal. For example, depending on manufacturing tolerances, wear, or other connection conditions, the first and second terminal engagement connections may have different electrical resistances and therefore generate different amounts of heat during current supply. Sensing the temperature of both terminal engagement connections allows for a higher average current to be obtained from the battery pack. Also, the second terminal temperature sensor may be located within said distance, for example along a path of the second current supply line, which may be at least partially formed by the second current supply cable. According to a further embodiment, the connector assembly may comprise a second current supply cable coupled to the second current supply connector terminal. The second terminal temperature sensor may be located less than 8 mm from a conductor of the second current supply cable or in direct abutment with the second current supply cable.

[0009] According to embodiments, the connector temperature sensing device may include a printed circuit board and two or more temperature sensors coupled to the printed circuit board. Such an arrangement allows for on-demand assembly during manufacture of the power tool or battery pack and ensures accurate and precise positioning of the temperature sensors.

[0010] According to an embodiment, the connector assembly may comprise a cable holder provided with one or more holes, each hole configured to at least partially surround and hold a respective current supply cable. The connector temperature sensing device comprises one or more temperature sensors arranged in said one or more holes. According to an embodiment, a printed circuit board of the connector temperature sensing device may also be carried by said cable holder.

[0011] According to an embodiment, the hand-held battery-operated power tool and / or the battery pack may further comprise a rigid body frame. The connector assembly comprises a rigid connector body and an elastic connector body support. The connector body is attached to the body frame via the connector body support. This allows the connector assembly to automatically align with the position of the mating connector when connected, regardless of dirt on the connector or slight misalignment within manufacturing tolerances. This allows for an improved electrical connection between the connector assembly and the mating connector. Thus, the power supply capability of the electrical connector connection formed by the connector assembly and the mating connector is increased, and heat generated at the electrical connector connection is reduced. According to an embodiment, the connector body support may be made of an elastomer, such as natural or synthetic rubber. The connector temperature sensing device may be attached to the rigid body frame via the elastic connector body support. The rigid body frame may be formed by the power tool housing or the battery housing, as the case may be. According to an embodiment, the battery housing may be configured to be rigidly connected to the power tool housing. Needless to say, each of the rigid body frame and the rigid connector body may be made of multiple elements rigidly interconnected. The rigid connector body may carry a pair of current-delivery connector terminals that may be configured as cantilever finger terminals that are configured to resiliently flex in a direction perpendicular to the mating direction of the mating connector during mating. The current-delivery connector terminals may be hermaphroditic.

[0012] According to an embodiment, the mating connector may be configured to be coupled to the connector assembly along the connection direction. The elastic connector body support is configured to allow the connector body to move elastically in the connection direction. According to an embodiment, the elastic connector body support may be configured to allow the connector body to move elastically in the connection direction with a maximum bending range of 0.5 mm to 4 mm. The elastic connector body support may be configured to allow the connector body to move elastically in a direction perpendicular to the connection direction or in any direction along a plane perpendicular to the connection direction. The rigid body frame may include a rigid connector sheath surrounding the connector body and extending along the connection direction.

[0013] According to an embodiment, the elastic connector body support may be configured as a cushion pad sandwiched between the connector body and the body frame, which may provide the desired flexibility in a compact space with low cost and complexity. The cushion pad may be made of an elastomer, such as a thermoplastic elastomer.

[0014] According to an embodiment, the cushion pad may have a thickness in the connection direction of between 2 mm and 10 mm. According to a further embodiment, the cushion pad may have a thickness in the connection direction of between 3 mm and 6 mm.

[0015] According to an embodiment, the cushion pad may be integrally formed with the cable holder. The cable holder may be made of, for example, a non-elastomeric resin, such as a non-elastomeric thermoplastic resin. The cable holder and the cushion pad may be formed as a two-component injection molded part. The connector temperature sensing device may be carried by the cable holder.

[0016] According to an embodiment, the handheld battery-operated power tool and / or the battery pack may further comprise a controller configured to set an upper limit of power that can be obtained from the battery pack based on a sensor signal from the connector temperature sensing device. According to a further embodiment, the controller may be configured to enable the power tool to operate in a normal power mode in response to determining that the connector temperature exceeds a power limit threshold temperature. The controller may also be configured to enable the power tool to operate in a high power mode in response to determining that the connector temperature is below a power limit release threshold temperature. The high power mode enables the power tool to operate at a higher power than the normal power mode. The power tool may comprise a user interface, e.g., an indicator light, configured to indicate whether the power tool is in the high power mode or the normal power mode. The power limit threshold temperature and the power limit release threshold temperature may be the same or different. The power limit threshold temperature and the power limit release threshold temperature may be static or may be dynamically set by the controller. For example, the controller may set the power limit threshold temperature and the power limit release threshold temperature based on a difference between a sensor signal from the connector temperature sensing device and a sensor signal from an ambient temperature sensor separate from the connector temperature sensing device. According to an embodiment, the power tool may be configured to obtain a power of more than 2.5 kW in a high power mode and less than 2.5 kW in a normal power mode. Exemplary suitable values ​​for the power limit threshold temperature and the power limit release threshold temperature may be, for example, between 50° C. and 100° C. Alternatively or additionally, the controller may be configured to initiate a connector overheat protection operation based on the sensor signal from the connector temperature sensing device. The connector overheat protection operation may include, for example, operating a cooling fan configured to cool the connector.

[0017] According to a third aspect, at least some of the above problems are solved or at least alleviated by a handheld battery-operated power tool. The handheld battery-operated power tool includes a body frame, a working implement carried by the body frame, an electric motor carried by the body frame and configured to operate the working implement, and a connector assembly configured to be releasably coupled to a mating connector of a removable and rechargeable battery pack to provide power to the electric motor. The connector assembly is configured to be coupled to the mating connector along a connection direction. The connector assembly includes a rigid connector body and an elastic connector body support. The elastic connector body support is configured as a cushion pad sandwiched between the connector body and the body frame to allow the connector body to move elastically in the connection direction.

[0018] According to a fourth aspect, at least some of the above problems are solved or at least alleviated by a rechargeable battery pack configured to be removably attached to a hand-held battery-operated power tool. The rechargeable battery pack includes a rigid body frame, a plurality of rechargeable battery cells held in the body frame, and a connector assembly configured to be releasably coupled to a mating connector of the power tool to provide power from the plurality of battery cells to the power tool. The connector assembly includes a rigid connector body and an elastic connector body support. The elastic connector body support is configured as a cushion pad sandwiched between the connector body and the rigid body frame to allow the connector body to move elastically in a connection direction.

[0019] According to respective embodiments of the hand tool and the battery pack, the cushion pad may be made of elastomer. The cushion pad may have an exemplary thickness of 2 mm to 10 mm, more preferably 3 mm to 6 mm. And / or the cushion pad may be configured to allow the connector body to move elastically in the connection direction with an exemplary maximum bending range of 0.5 mm to 4 mm. The cushion pad may be integrally formed with a cable holder provided with one or more holes. Each hole is configured to at least partially surround and hold a respective current supply cable. The cable holder may be non-elastomeric and may be integrally formed with the cushion pad, for example by two-component injection molding. Again, according to embodiments, the rigid body frame may be formed by the power tool housing or the battery housing, as the case may be. The battery housing may be configured to be rigidly connected to the power tool housing. Each of the rigid body frame and the rigid connector body may consist of a plurality of rigidly interconnected elements. The rigid connector body may carry a set of current supply connector terminals. The current supplying connector terminals may be cantilever finger terminals configured to resiliently bend in a direction perpendicular to the mating direction of the mating connector during connection. The current supplying connector terminals may be hermaphroditic. The elastic connector body support may be configured to allow the connector body to resiliently move in a direction perpendicular to the connection direction or in any direction along a plane perpendicular to the connection direction. The body frame may include a connector sheath surrounding the connector body and extending along the connection direction.

[0020] According to a fifth aspect, at least some of the above problems are solved or at least alleviated by a combination of a hand-held battery-operated power tool according to any of the first and third aspects with a battery pack according to any of the second and fourth aspects. In such a combination, a connector assembly of the battery pack forms a mating connector to be connected to a connector assembly of the power tool. Alternatively, a connector assembly of the power tool forms a mating connector to be connected to a connector assembly of the battery pack. According to an exemplary combination, the connector assembly of the power tool may include the connector temperature sensing device described above, and the connector assembly of the battery pack may include the cushion pad described above. Alternatively, the connector assembly of the power tool may include the cushion pad described above, and the connector assembly of the battery pack may include the connector temperature sensing device described above.

[0021] According to a sixth aspect, at least some of the above problems are solved or at least alleviated by a tool system. The tool system comprises a first hand-held battery-powered power tool, a second hand-held battery-powered power tool, and a removable and rechargeable battery pack configured to be alternately coupled to the first hand-held battery-powered power tool and the second hand-held battery-powered power tool. The second hand-held battery-powered power tool has a power limit that can be obtained from the battery pack, the power limit being independent of the temperature of the electrical coupling connection between the battery pack and the second hand-held battery-powered power tool. The first hand-held battery-powered power tool is a hand-held battery-powered power tool according to the first aspect above, and the power limit of the first hand-held battery-powered power tool may be set to a higher value than the power limit of the second hand-held battery-powered power tool. Such a system allows interoperability between high power tools and conventional low power tools and the battery pack while maximizing the power of the high power tool.

[0022] According to a seventh aspect, at least some of the above problems are solved or at least alleviated by a method of controlling a hand-held battery-powered power tool to obtain power from a battery pack. The method includes the steps of: sensing a temperature of a connector of an electrical coupling connection between the hand-held battery-powered power tool and the battery pack; enabling the power tool to operate in a normal power mode in response to determining that the connector temperature exceeds a power limit threshold temperature; and enabling the power tool to operate in a high power mode in response to determining that the connector temperature is below a power limit release threshold temperature, the high power mode allowing the power tool to operate at a higher power than the normal power mode. The power limit threshold temperature and the power limit release threshold temperature may be the same or different.

[0023] According to an eighth aspect, there is provided a data processing device comprising one or more processors and a memory configured to perform the method set forth above. According to a ninth aspect, there is provided a computer program product comprising instructions for performing the method set out above when the program is run on a processor.

[0024] According to a tenth aspect, there is provided a computer readable storage medium (99) having stored thereon the computer program product described above. It should be noted that embodiments of the present invention may be implemented by all possible combinations of the features recited in the claims. Furthermore, it is understood that various embodiments described with respect to a device may be combined with a method, or alternatively, various embodiments described with respect to a method may be combined with an apparatus.

[0025] The above, as well as additional objects, features, and advantages of the present invention will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the invention, taken in conjunction with the accompanying drawings in which like reference numerals are used for similar elements and in which: [Brief description of the drawings]

[0026] [Figure 1A] FIG. 1 is a side plan view of a handheld battery powered chain saw having a rechargeable battery. [Figure 1B] FIG. 1B is a plan view of the chain saw of FIG. 1A from above. [Figure 2A] 1B is a perspective view of the power unit body of the chainsaw of FIG. 1A during insertion of a battery; FIG. [Figure 2B] 2B is an enlarged view of the area indicated by B in FIG. 2A showing the connector assembly of the chainsaw. [Figure 2C] An enlarged view of a portion of FIG. 2B. [Diagram 3] FIG. 1B is a top view of the battery of FIG. 1A. [Figure 4] 4 is a perspective view of a cross section of the battery of FIG. 3 as indicated by line IV-IV of FIG. 3. [Figure 5A] FIG. 2C is an exploded perspective view of the connector assembly of FIG. 2B. [Figure 5B] FIG. 2C is an exploded view of the connector assembly of FIG. 2B from a different perspective. [Figure 6] 1B is a perspective view of a cross section of the chainsaw and battery of FIG. 1A as indicated by line VI-VI of FIG. 1A. [Figure 7A] 1B is a perspective view of a pair of current supply connectors of the chainsaw and battery of FIG. 1A before connection. [Figure 7B] 7B is a cross-sectional view of the current supply connector of FIG. 7A after connection. [Figure 8] FIG. 2 illustrates a tool system including the chainsaw and battery of FIG. 1 and an additional chainsaw. [Figure 9] 1B is a flow chart illustrating a method of controlling the chainsaw and battery of FIG. 1A. [Figure 10] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] All the figures are schematic and not necessarily drawn to scale, and generally show only parts necessary to explain the embodiments, and other parts may be omitted. FIG. 1A shows a hand-held battery-operated power tool implemented as an electric chain saw 10. The power tool 10 includes a power unit body 12 provided with a pair of handles 14a, 14b. The handles 14a, 14b allow an operator (not shown) to hold and operate the power tool 10. The pair of handles includes a front handle 14a for holding typically with the left hand and a rear handle 14b for holding typically with the right hand. The rear handle 14b is located at the top of the power unit body 12. That is, the exemplary chain saw 10 is of a so-called top handle type. However, it will be understood that the disclosure of this specification is equally applicable to rear handle type chain saws and other types of hand-held battery-operated power tools. The power unit body 12 holds and operates a working assembly. In the illustrated case, the working assembly is configured as a cutting assembly including a saw chain 16 and a long guide bar 18 for guiding the saw chain 16 in a long loop shape. The cutting assembly extends in a longitudinal direction L from a front end of the power unit body 12. The power tool 10 further includes a removable and rechargeable battery pack 20, an electric motor 22 (shown only diagrammatically in FIG. 1A by a dashed circle), and a finger-operable trigger 24 that allows an operator to control the flow of power from the battery pack 20 to the electric motor 22, thereby enabling the operator to selectively move the saw chain 16 with the electric motor 22. The power tool 10 further includes a controller 26 (shown only diagrammatically in FIG. 1A by a dashed rectangle) configured to control the electric motor 22 based on input from the trigger 24. The trigger 24 extends downwardly from a bottom surface of the rear handle 14b and is movable between a released position (shown) that stops the saw chain 16 and a fully depressed position (not shown) that operates the electric motor 22 to move the saw chain 16.

[0028] 1B shows the power tool 10 from above without the saw chain 16. The guide bar extends along a longitudinal direction L in a main extension plane P. 2A, the power supply unit body 12 includes a battery compartment 28 molded to accommodate and surround the battery pack 20. The battery compartment 28 includes an electrical connector 30. The electrical connector 30 is configured to releasably couple to a mating electrical connector (not shown in FIG. 2A) of the battery pack 20 to supply power to the electric motor 22 (FIG. 1A). The battery pack 20 is insertable into the battery compartment 28 of the power supply unit body 12 along an insertion direction C, which in the illustrated example extends perpendicular to the main extension plane P (FIG. 1B) of the guide bar 18 (FIG. 1B). The insertion direction C also defines a connection direction for connecting the electrical connector of the battery pack 20 to the electrical connector 30 of the power tool 10. The power supply unit body 12 includes a rigid power tool housing 13. The power tool housing 13 functions as a rigid body frame of the power supply unit body 12 to provide structural support to various components. The power tool housing 13 includes a first housing portion 13a and a second housing portion 13b. The first and second housing portions 13a, 13b are firmly joined to each other.

[0029] 2B shows the connector 30 in more detail. The connector 30 is formed by a connector assembly 32 comprising a rigid connector body 34 having a pair of connector terminals 36. The connector terminals 36 are arranged so as to be accessible from the exterior of the housing 13 (FIG. 2A) when the battery pack 20 (FIG. 1A) is not connected to the housing 13. The first housing part 13a comprises a rigid connector sheath 38 which surrounds the connector body 34 and forms a sleeve extending along the connection direction C (FIG. 2A).

[0030] 2C illustrates the connector assembly 32 in further detail. The set of connector terminals 36 includes a first current supply connector terminal 40a and a second current supply connector terminal 40b, each configured to mate with a respective mating current supply connector terminal (not shown) of a mating connector (not shown). The first current supply connector terminal 40a is a positive terminal configured to receive current from the battery pack 20. The second current supply terminal 40b is a negative terminal configured to return current to the battery pack 20. A set of control terminals 42 allows for the exchange of control signals between the power tool 10 and the battery pack 20, e.g., for power control, exchange of battery status information, etc.

[0031] FIG. 3 shows a side of the battery pack 20 facing the electrical connector 30 of the power tool 10 in FIG. 2A. The battery pack 20 comprises a plurality of rechargeable battery cells (not shown) of the lithium-ion type arranged in a battery housing 21. The battery pack 20 further comprises an electrical connector 130. The electrical connector 130 is configured to be releasably coupled to a mating electrical connector of the power tool 10, i.e. the electrical connector 30 of the power tool 10 (FIG. 2A), to supply electrical power to the electric motor 22 (FIG. 1A) of the power tool 10. Similar to the connector 30 of the power tool, the connector 130 of the battery pack 20 is formed by a connector assembly 132. The connector assembly 132 comprises respective rigid connector bodies 134 having a pair of connector terminals 136. The connector terminals 136 are accessible from the outside of the housing 21 when the battery pack 20 is not connected to the power tool 10 (FIG. 1). The rigid connector sheath 138 is formed by the battery housing 21 and surrounds the connector body 134 to form a sleeve extending along the connection direction C (FIG. 2A).

[0032] FIG. 4 shows a cross section of the battery pack 20. The set of connector terminals 136 includes a first current supply connector terminal 140a and a second current supply connector terminal 140b, each configured to engage with a mating current supply connector terminal, i.e., the corresponding first and second current supply connector terminals 40a, 40b (FIG. 2C) of the connector 30 of the power tool 10. The cross section also shows the battery cells 45 of the battery pack 20. The cells 45 are electrically interconnected in groups in series and parallel configurations in a manner not shown to provide a combined voltage of approximately 36V between the first current supply connector terminal 140a and the second current supply connector terminal 140b. Current supply cables 144a, 144b are connected to the first and second current supply connector terminals 140a, 140b, respectively, to provide power from the battery cells 45. Similar to the power tool housing 13 (FIG. 2A), the battery pack housing 21 includes a number of rigidly interconnected parts 21a, 21b, 21c, one of which, part 21a, forms a connector sheath 138.

[0033] Returning now to the connector assembly 32 of the power tool 10 (FIG. 2A), FIG. 5A shows a rigid connector body 34 having current supply connector terminals 40a, 40b (shown in FIG. 2C, not shown in FIG. 5A). The connector body 34 is resiliently connected to the body frame of the power tool 10 represented by the second housing part 13b via an elastic connector body support 48. The elastic connector body support 48 is configured as a rubber cushion pad disposed between the connector body 34 and the second housing part 13b. Both the connector body support 48 and the connector body 34 are attached to a pair of screw fixing posts 50 formed integrally with the second housing part 13b by a pair of mounting screws 52. One of the mounting screws 52 is shown. The resiliently attached connector assembly 32 can automatically align with the position of the mating connector when connected within a bending range allowed by the flexibility of the connector body support 48. In particular, the connector body support allows the rigid connector body 34 to bend along the connection direction C and in a plane perpendicular to the connection direction C relative to the rigid housing 13 (FIG. 2A). The cushion pad has a thickness T of about 4 mm in the connection direction and allows the connector body 34 to move elastically in the connection direction C with a maximum bending range of about 1 mm. The cushion pad 48 is integrally formed with the cable holder 54. The cable holder 54 includes cable holding holes 56a, 56b accessible from the edge. Thereby, the current supply cables 44a, 44b may be pressed into the respective holes 56a, 56b of the cable holder 54 in a cable insertion direction perpendicular to the extension direction of the cables to the position shown in FIG. 5B.

[0034] FIG. 5B shows the connector assembly 32 having a first current supply cable 44a and a second current supply cable 44b. The first current supply cable 44a is connected to the first current supply terminal 40a and is held in a first hole 56a of the cable holder 54. The second current supply cable 44b is connected to the second current supply terminal 40b and is held in a second hole 56b of the cable holder 54. The cable holder 54 also carries a connector temperature sensing device 58. The temperature sensing device 58 is configured to sense the temperature of the connector assembly. The temperature sensing device 58 includes a first terminal temperature sensor 60a disposed in the first hole 56a of the cable holder 54 and a second terminal temperature sensor 60b disposed in the second hole 56b of the cable holder 54. Thus, the cable holder 54 holds the terminal temperature sensors 60a, 60b in direct contact with the current supply cables 44a, 44b, respectively. The terminal temperature sensors 60a, 60b are connected to a printed circuit board 62 carried by the cable holder 54. The printed circuit board 62 is only shown diagrammatically in the view of Figure 5B. However, it will be understood that the printed circuit board 62 may be configured to be attached to the housing 13 (Figure 2A), for example by means of screws 52, for example by sandwiching the printed circuit board 62 between the connector body 34 and the connector body support 48, or between the connector body support 48 and the second housing part 13b.

[0035] The terminal temperature sensors 60a, 60b are connected to the control device 26 (FIG. 1A) in a manner not shown. The controller 26 is configured to set a power upper limit of the power that the power tool 10 (FIG. 1A) can obtain from the battery pack 20 (FIG. 1) based on the sensor signal from the connector temperature sensing device 58. In response to detecting that the temperature of the connector 30 (FIG. 2A), represented by the maximum temperature of the temperature of the current supply cable 44, exceeds a power limit threshold temperature, e.g., 60 degrees, the controller 26 limits the power tool 10 to operate in a normal power mode, e.g., 2.2 kW. If the controller 26 determines that the temperature of the connector 30 (FIG. 2A) is below a power limit release threshold temperature, e.g., 50 degrees, the controller 26 allows the power tool 10 to operate in a high power mode, e.g., 2.7 kW. An indicator light 64 (FIG. 1B), which may include a message "power boost available," illuminates to inform the power tool operator that the power tool 10 is in the high power mode. By setting the power limit threshold temperature higher than the power limit release threshold temperature, the power tool 10 does not switch between the normal mode and the high power mode excessively.

[0036] The cross-sectional view of Figure 6 shows the location of the connector assembly 32 within the housing 13 of the power tool 10. Screws 52 attach the connector body 34 to threaded fixing posts 50 on the inner surface of the second housing portion 13b through the elastic connector body support 48. Only the second and third housing portions 13b, 13c of the battery pack 20 are shown in Figure 6.

[0037] 7A shows the first current supply connector terminal 40a and the first current supply cable 44a of the connector assembly 32 (FIG. 2C) of the power tool 10 (FIG. 1A) and the first current supply connector terminal 140a and the first current supply cable 144a of the connector assembly 132 (FIG. 3) of the battery pack 20 (FIG. 1A) before connection along the connection direction C. The first current supply cable 44a of the power tool 10 has a first cable conductor 66 that forms a first current supply line together with the first current supply connector terminal 40a and a first cable insulating sheath 68 that surrounds the first cable conductor 66. Each current supply connector terminal 40a, 140a is configured as a cantilever finger terminal that is configured to bend elastically in a direction perpendicular to the connection direction C during connection to reach the position shown in FIG. 7B when connected.

[0038] In the cross section of FIG. 7B showing the cable holder 54 and the first terminal temperature sensor 60a, the first current supply connector terminal 40a of the power tool 10 (FIG. 1A) engages with the first current supply connector terminal 140a of the battery pack 20 (FIG. 1A) at the first terminal engagement connection 70. The first terminal temperature sensor 60a is located at a distance D1 of about 15 mm from the first terminal engagement connection 70 along the current supply path formed by the first current supply wire. The current supply wire also acts as a heat transfer wire so that the temperature of the first terminal engagement connection 70 is well represented by the reading of the first terminal temperature sensor 60a abutting the first current supply cable 44a at a distance D2 of about 2 mm from the conductor 66 of the first current supply cable 44a. The first terminal temperature sensor 60a is connected to the printed circuit board 62 (FIG. 5B) via a lead wire 69.

[0039] It is understood that second current supply connector terminal 40b (FIG. 2C) of power tool 10 (FIG. 1A) may engage with second current supply connector terminal 140b (FIG. 3) of battery pack 20 (FIG. 3) at a second terminal engaging connection that may be identical to first terminal engaging connection 70. It is also understood that second terminal temperature sensor 60b (FIG. 5B) may be positioned accordingly.

[0040] Similarly, it will be appreciated that alternatively or additionally, the connector assembly 132 (FIG. 3) of the battery pack 20 may include a similar connector temperature sensing device that may communicate the connector temperature to the controller 26 of the power tool 10. Alternatively, the connector temperature sensing device may communicate the connector temperature to a controller integrated within the battery pack, which may then limit the maximum power available to the battery pack.

[0041] Similarly, it will be understood that the rigid connector body 134 of the connector assembly 132 of the battery pack 20 may be elastically connected to the housing 21 of the battery pack 20 via an elastic cushion pad to allow the connector body 134 to flex relative to the battery pack housing 21.

[0042] FIG. 8 shows a tool system 80 including the power tool 10 of FIG. 1A, a second hand-held battery-operated power tool 810, and the battery pack 20 of FIG. 3. The battery pack 20 is configured to be alternately coupled to the power tool 10, which is a first power tool, and the second power tool 810. The second power tool 810 is substantially identical to the first power tool 10, but differs from the first power tool 10 in that the second power tool 810 is not provided with a terminal temperature sensing device 58 (FIG. 5B). Having no information about the connector temperature, the controller of the second power tool 810 is configured to enable only the normal power mode, independent of the temperature change of the electrical connector 830 of the second power tool 810. Meanwhile, the first power tool 10 may be set to a high power mode, allowing the first power tool 10 to be operated at a higher power than the second power tool 810 whenever the electrical connector 30 of the first power tool 10 is sufficiently cool. For clarity, although the tool system 80 is illustrated with reference to two chainsaws 10, 810, this is not required. The tool system may consist of or include other types of hand held battery operated power tools, such as two leaf blowers, a leaf blower and a hedge trimmer, a chainsaw and a clearing saw, etc.

[0043] Figure 9 illustrates a method of controlling the hand-held battery operated power tool 10 of Figure 1A to obtain power from the battery pack 20. The method is implemented in the controller 26, which includes a processor and memory for this purpose. Alternatively, the method may be implemented in a battery controller within the battery pack 20.

[0044] In step 901, the controller 26 senses the temperature of the connector using the connector temperature sensing device 58. Specifically, the controller 26 senses the temperature of the connector 30 (FIG. 2A) or 130 (FIG. 3) of the electrical coupling connection between the hand-held battery-operated power tool 10 and the battery pack 20.

[0045] In step 902, the controller 26 determines whether the connector temperature exceeds the power limit threshold temperature. If the connector temperature exceeds the power limit threshold temperature, the controller sets the power tool 10 or battery pack 20 to a mode that allows the power tool 10 to operate in a normal power mode, while preventing operation in a high power mode.

[0046] In step 903, the controller 26 determines whether the connector temperature is less than the power limit release threshold temperature. If the connector temperature is less than the power limit release threshold temperature, the controller 26 sets the power tool 10 or the battery pack 20 to a mode that allows the power tool 10 to operate in a high power mode. The high power mode allows the power tool 10 to operate at a higher power than the normal power mode.

[0047] Figure 10 shows a computer readable storage medium embodied as a CD (compact disc) 99. The CD 99 has stored thereon a computer program product including instructions for performing any of the above-described methods when the program is executed on a processor.

[0048] The present invention has been described above primarily with reference to certain embodiments. However, as will be readily appreciated by those skilled in the art, other embodiments than those disclosed above are equally possible within the scope of the present invention, as set forth in the appended claims.

[0049] For example, the present invention has been described with reference to a rear handle type chain saw. However, it will be understood that the teachings herein are equally applicable to top handle type chain saws. The temperature sensor of the connector temperature sensing device need not be located in direct contact with the current supply cable, but may be located in another suitable location within the connector assembly.

[0050] In the claims, the word "comprising" does not exclude other elements or steps and the indefinite article "a" or "an" does not exclude a plurality.

Claims

1. A handheld battery-powered power tool A working implement (16); an electric motor (22) configured to operate the work implement (16); a connector assembly (32) configured to be releasably coupled to a mating connector (130) of a removable and rechargeable battery pack (20) to supply power to the electric motor (22); The connector assembly (32) includes a connector temperature sensing device (58) configured to sense a temperature of the connector assembly (32).

2. A rechargeable battery pack configured to be removably attached to a hand-held battery-operated power tool (10), the rechargeable battery pack comprising: a plurality of rechargeable battery cells (45); a connector assembly (132) configured to be releasably coupled to a mating connector (30) of the power tool (10) to supply power from the plurality of battery cells (45) to the power tool (10). The rechargeable battery pack, wherein the connector assembly (132) includes a connector temperature sensing device (58) configured to sense a temperature of the connector assembly (132).

3. The connector assembly (32, 132) includes a first current supply connector terminal (40a, 140a); The first current supply connector terminal (40a, 140a) is configured to engage with a first current supply connector terminal (140a, 40a) of the mating connector (130, 30) at a first terminal engagement connection portion (70); 3. The hand-held battery operated power tool or battery pack of claim 1 or 2, wherein the connector temperature sensing device (58) comprises a first terminal temperature sensor (60a) located less than 50 mm from the first terminal engaging connection (70).

4. The connector assembly (32, 132) includes a first current supply cable (44a, 144a); 4. The hand-held battery-operated power tool or battery pack of claim 1, wherein the first terminal temperature sensor (60a) is positioned less than 8 mm from a conductor (66) of the first current supply cable (44a, 144a).

5. The connector assembly (32, 132) includes a second current supply connector terminal (40b, 140b); the second current supply connector terminal (40b, 140b) is configured to engage with a second current supply connector terminal (140b, 40b) of the mating connector (130, 30) at a second terminal engagement connection portion (70); 5. The hand-held battery operated power tool or battery pack of claim 3 or 4, wherein the connector temperature sensing device (58) comprises a second terminal temperature sensor (60b) located less than 50 mm from the second terminal engaging connection (70).

6. 6. The hand-held battery operated power tool or battery pack of claim 1, wherein the connector temperature sensing device (58) comprises a printed circuit board (62) and two or more temperature sensors (60a, 60b) coupled to the printed circuit board (62).

7. The connector assembly (32, 132) includes a cable holder (54) having one or more holes (56a, 56b) therein; each of said one or more holes (56a, 56b) configured to at least partially surround and retain a respective current supply cable (44a, 44b, 144a, 144b); 7. The hand-held battery operated power tool or battery pack of claim 1, wherein the connector temperature sensing device (58) comprises one or more temperature sensors (60a, 60b) disposed in the one or more holes (56a, 56b).

8. Further comprising a rigid body frame (13, 21); The connector assembly (32, 132) comprises a rigid connector body (34, 134) and a resilient connector body support (48); 8. A hand-held battery-operated power tool or battery pack according to any one of claims 1 to 7, wherein the connector body (34, 134) is attached to the body frame (13, 21) via the connector body support (48).

9. the mating connector (130, 30) is configured to be coupled to the connector assembly (32, 132) along a connection direction (C); 9. The hand-held battery-operated power tool or battery pack of claim 8, wherein the elastic connector body support (48) is configured to allow the connector body (34, 134) to move elastically in the connection direction (C).

10. 10. The hand-held battery-operated power tool or battery pack of claim 9, wherein the elastic connector body support (48) is configured as a cushion pad sandwiched between the connector body (34, 134) and the body frame (13, 21).

11. The hand-held battery-operated power tool or battery pack according to claim 10, wherein the cushion pad (48) has a thickness (T) in the connection direction of 2 mm to 10 mm.

12. 12. The hand-held battery-operated power tool or battery pack according to claim 10 or 11, wherein the cushion pad (48) is integrally formed with a cable holder (54).

13. 13. The hand-held battery-operated power tool or battery pack of claim 1, further comprising a controller (26) configured to set an upper limit on power that can be drawn from the battery pack (20) based on a sensor signal from the connector temperature sensing device (58).

14. A handheld battery-powered power tool A main body frame (13); a working implement (16) carried by the body frame (13); an electric motor (22) carried by the body frame and configured to operate the work implement (16); a connector assembly (32) configured to be releasably coupled to a mating connector (130) of a removable and rechargeable battery pack (20) to supply power to the electric motor (22); The connector assembly (32) is configured to be coupled to the mating connector (130) along a connection direction (C); The connector assembly (32) comprises a rigid connector body (34) and a resilient connector body support (48); The elastic connector body support (48) is configured as a cushion pad sandwiched between the connector body (34) and the main body frame (13) to enable the connector body (34) to move elastically in the connection direction (C).

15. A rechargeable battery pack configured to be removably attached to a hand-held battery-operated power tool (10), the rechargeable battery pack (20) comprising: A rigid body frame (21); a plurality of rechargeable battery cells (45) held in the body frame (21); a connector assembly (132) configured to be releasably coupled to a mating connector (130) of the power tool (10) along a connection direction (C) in order to supply power from the plurality of battery cells (45) to the power tool (10). The connector assembly (132) comprises a rigid connector body (134) and a resilient connector body support (48); The rechargeable battery pack, wherein the elastic connector body support (48) is configured as a cushion pad sandwiched between the connector body (134) and the rigid body frame (21) to allow the connector body (134) to move elastically in the connection direction (C).

16. A combination of a hand-held battery-operated power tool (10) according to claim 14 or any one of the claims dependent on claim 1 with a battery pack (20) according to claim 15 or any one of the claims dependent on claim 2.

17. A tool system A first handheld battery-operated power tool (10); a second handheld battery-operated power tool (810); a removable and rechargeable battery pack (20) configured to be alternately coupled to the first handheld battery-powered power tool (10) and the second handheld battery-powered power tool (810); the second handheld battery-operated power tool (810) has an upper limit of power that can be obtained from the battery pack (20); the power limit is independent of a temperature of an electrical coupling connection between the battery pack (20) and the second hand-held battery-operated power tool (810); The first hand-held battery-powered power tool (10) is a hand-held battery-powered power tool (10) according to claim 13 in combination with claim 1, The power upper limit of the first handheld battery-powered power tool (10) may be set to a value higher than the power upper limit of the second handheld battery-powered power tool (810).

18. A method for controlling a handheld battery-operated power tool (10) to obtain power from a battery pack (20), sensing a temperature of a connector of an electrical coupling connection (70) between the hand-held battery-operated power tool (10) and the battery pack (20); in response to determining that the connector temperature exceeds a power limit threshold temperature, enabling the power tool to operate in a normal power mode; and enabling the power tool (10) to operate in a high power mode in response to determining that the connector temperature is below a power limit release threshold temperature, the high power mode enabling the power tool (10) to operate at a higher power than the normal power mode.

19. A data processing device (26) comprising one or more processors and a memory configured to perform the method of claim 18.

20. A computer program product comprising instructions for performing the method according to claim 18 when the program is executed on a processor.

21. A computer readable storage medium (99) having stored thereon a computer program product according to claim 20.

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