Handheld battery-powered power tool, rechargeable battery pack, and method of controlling such a power tool and battery pack

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-powered power tools, rechargeable battery packs, combinations of such power tools and battery packs, and systems including them. The present invention also relates to methods of controlling such power tools and battery packs, and computer programs for implementing such methods.

Background Art

[0002] Hand-held power tools such as chain saws have been well-known for over 100 years. Considering power output and operating time relative to weight, most chain saws are still driven by two-stroke type internal combustion engines, but the popularity of battery-powered chain saws is increasing. However, obtaining high power output without compromising other aspects of chain saws such as cost, weight, battery life before recharging, and the usefulness of the battery for other types of products remains an issue.

Summary of the Invention

Problems to be Solved by the Invention

[0003] An object of the present invention is to solve some or all of the above problems or at least mitigate them.

Means for Solving the Problems

[0004] To achieve this object, a hand-held battery-powered power tool is provided. The hand-held battery-powered power tool includes a working tool, an electric motor configured to operate the working tool, and a connector assembly configured to be releasably coupled to a connector that is a mating partner of a removable and rechargeable battery pack to supply power to the electric motor. The connector assembly includes a connector temperature sensing device configured to sense the temperature of the connector assembly. Since the connector temperature sensing device can monitor the actual state of the connector assembly, it enables obtaining a higher current from the battery pack at least temporarily than would be the case without the connector temperature sensing device. For example, by using lithium-ion cells in the battery pack, in a power tool system designated to operate at 36V depending on the state of charge of the battery pack, a relatively wide operating voltage, for example, from about 25V to about 42V, may be enabled. Such a wide voltage range may require an increased current during discharge of the battery pack as the voltage drops to maintain a specific output of the power tool. This generates more heat in the connector assembly. By monitoring the temperature of the connector assembly, it becomes possible to increase the average power of the power tool during the discharge cycle of the battery pack. The connector temperature sensing device may include one or more temperature sensors configured, for example, as negative temperature coefficient types such as thermistors (plural possible). According to an embodiment, the power tool may be configured to obtain a maximum power exceeding 1.8 kW from the battery pack. For example, the power tool may be an outdoor power tool, such as a leaf blower, or a vegetation cutter such as a chainsaw or clearing saw, or a construction tool such as a power cutter / cut-off machine for cutting bricks, metal, and concrete. The power tool may also include a battery compartment configured to accommodate and hold the battery pack.

[0005] According to a second aspect, at least some of the above-described problems are solved or at least mitigated by a rechargeable battery pack. The rechargeable battery pack is configured to be removably attached to a hand-held battery-powered power tool. The rechargeable battery pack includes a plurality of rechargeable battery cells and a connector assembly configured to be releasably coupled to a connector, which is a mating part of the power tool, to supply power from the plurality of battery cells to the power tool. The connector assembly includes a connector temperature sensing device configured to sense the 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 disposed within a battery housing. The connector assembly may include a set of current supply connector terminals disposed so as 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 disposed at a certain distance from the rechargeable battery cells. Thereby, heat transfer from the rechargeable battery cells to the connector temperature sensing device is reduced. The distance between the connector temperature sensing device and the nearest battery cell is preferably more than 30 mm. Also in this case, the connector temperature sensing device may include one or more temperature sensors that can be configured, for example, as a negative temperature coefficient type, such as a thermistor (s). The battery pack may be configured to supply a maximum power of more than 1.8 kW to the power tool.

[0006] According to embodiments of the handheld battery-operated power tool and / or battery pack, the connector assembly may include 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 may include 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 this distance along a path of the first current supply line, which may be at least partially formed, for example, by the first current supply cable. According to further embodiments, 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 may be positioned less than 8 mm from the 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 positioned 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 a 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 temperatures of both terminal engagement connections enables a higher average current to be obtained from the battery pack. The second terminal temperature sensor may also be located within the 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 include 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 the conductor of the second current supply cable or in direct contact 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 include 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 connector temperature sensing device includes one or more temperature sensors disposed in the one or more holes. According to an embodiment, the printed circuit board of the connector temperature sensing device may also be carried by the cable holder.

[0011] According to an embodiment, the hand-held battery-powered power tool and / or the battery pack may further include a rigid body frame. The connector assembly includes a rigid connector body and an elastic connector body support. The connector body is attached to the body frame via the connector body support. Thereby, the connector assembly can be automatically aligned with the position of the mating connector during connection, regardless of dirt on the connector or slight misalignment within manufacturing tolerances. This enables an improved electrical connection between the connector assembly and the mating connector. Therefore, the power supply capacity of the electrical connector connection formed by the connector assembly and the mating connector is increased, and the 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 rubber 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, in some cases, be formed by the power tool housing or the battery housing. According to an embodiment, the battery housing may be configured to be firmly connected to the power tool housing. Needless to say, each of the rigid body frame and the rigid connector body may be composed of a plurality of rigidly interconnected elements. The rigid connector body may carry a set of current supply connector terminals. The current supply connector terminals may be configured as cantilever finger terminals that elastically bend in a direction perpendicular to the connection direction of the mating connector during connection. The current supply connector terminals may be of the male-female type.

[0012] According to embodiments, the mating connector may be configured to be coupled to the connector assembly along a connecting direction. The elastic connector body support is configured to allow the connector body to move elastically in the connecting direction. According to embodiments, the elastic connector body support may be configured to allow the connector body to move elastically in the connecting 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 connecting direction or in any direction along a plane perpendicular to the connecting direction. The rigid body frame may include a rigid connector sheath surrounding the connector body and extending along the connecting direction.

[0013] According to embodiments, the resilient connector body support may be configured as a cushion pad sandwiched between the connector body and the body frame, thereby providing 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 2 mm to 10 mm. According to a further embodiment, the cushion pad may have a thickness in the connection direction of 3 mm to 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 embodiments, the handheld battery-operated power tool and / or the battery pack may further include a controller configured to set an upper limit on power that can be drawn from the battery pack based on a sensor signal from the connector temperature sensing device. According to further embodiments, 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 in the normal power mode. The power tool may include a user interface, such as an indicator lamp, 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 greater than 2.5 kW in a high power mode and a power 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-mentioned 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 work implement carried by the body frame, an electric motor carried by the body frame and configured to operate the work implement, and a connector assembly configured to be releasably coupled to a mating connector of a detachable and rechargeable battery pack to supply 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 elastic movement of the connector body in the connection direction.

[0018] According to a fourth aspect, at least some of the above-mentioned problems are solved or at least alleviated by a rechargeable battery pack configured to be removably attached to a handheld 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 supply 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 elastic movement of the connector body in a connection direction.

[0019] According to each embodiment of the hand-held tool and the battery pack, the cushion pad may be made of an 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 enable the connector body to move elastically in the connection direction within 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 each 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. Also in this case, according to the embodiment, the rigid body portion frame may in some cases be formed by the power tool housing or the battery housing. The battery housing may be configured to be firmly connected to the power tool housing. Each of the rigid body portion 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 supply connector terminals may be cantilever finger terminals configured to elastically bend in a direction perpendicular to the connection direction of the mating connector during connection. The current supply connector terminals may be of the same gender. The elastic connector body support may be configured to enable 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 body portion frame may surround the connector body and may include a connector sheath extending along the connection direction.

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

[0021] According to a sixth aspect, at least some of the above problems are solved or at least mitigated by a tool system. The tool system includes 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 upper limit that can be obtained from the battery pack, and the power upper limit is 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 the hand-held battery-powered power tool according to the first aspect above, and the power upper limit of the first hand-held battery-powered power tool may be set to a value higher than the power upper limit of the second hand-held battery-powered power tool. Such a system enables interoperability between the high-power tool and the conventional low-power tool 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 mitigated by a method of controlling a hand-held battery-powered power tool to obtain power from a battery pack. The method includes sensing the 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 a determination 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 a determination that the connector temperature is less than a power limit release threshold temperature, where the high power mode enables 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 execute the above method. According to a ninth aspect, there is provided a computer program product including instructions for executing the above method when the program is executed on a processor.

[0024] According to a tenth aspect, there is provided a computer-readable storage medium (99) storing the above computer program product. It should be noted that the embodiments of the present invention can be implemented by all possible combinations of the features described in the claims. Further, it is understood that the various embodiments described with respect to the device can be combined with the method. Or, it is understood that the various embodiments described with respect to the method can be combined with the apparatus.

[0025] The above and additional objects, features, and effects of the present invention will be better understood through the following illustrative and non-limiting detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings in which like elements are designated by the same reference numerals.

Brief Description of the Drawings

[0026] [Figure 1A] Plan view of a hand-held battery-powered chainsaw having a rechargeable battery, as seen from the side. [Figure 1B] Plan view of the chainsaw of FIG. 1A, as seen from above. [Figure 2A] Perspective view of the power unit body of the chainsaw of FIG. 1A during battery insertion. [Figure 2B] Enlarged view of the region indicated by B in FIG. 2A, showing the connector assembly of the chainsaw. [Figure 2C] Partial enlarged view of FIG. 2B. [Figure 3] Plan view of the battery of FIG. 1A. [Figure 4] Perspective view of the cross-section of the battery of FIG. 3, taken along line IV-IV of FIG. 3. [Figure 5A] Exploded perspective view of the connector assembly of FIG. 2B. [Figure 5B] Exploded view of the connector assembly of FIG. 2B, seen from different viewpoints. [Figure 6] Perspective view of the cross-section of the chainsaw and battery of FIG. 1A, taken along line VI-VI of FIG. 1A. [Figure 7A] Perspective view of a set of current supply connectors of the chainsaw and battery of FIG. 1A before connection. [Figure 7B] Cross-sectional view of the current supply connector of FIG. 7A after connection. [Figure 8] Diagram showing a tool system comprising the chainsaw and battery of FIG. 1 and an additional chainsaw. [Figure 9] Flowchart showing a method of controlling the chainsaw and battery of FIG. 1A. [Figure 10] Perspective view of a data medium.

DETAILED DESCRIPTION OF THE INVENTION

[0027] All the figures are schematic and are not necessarily drawn to scale. Generally, only the parts necessary for explaining the embodiments are shown, and other parts may be omitted. FIG. 1A illustrates a handheld battery-powered power tool embodied as an electric chainsaw 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, typically for holding with the left hand, and a rear handle 14b, typically for holding with the right hand. The rear handle 14b is located at the top of the power unit body 12. In other words, the exemplary chainsaw 10 is a so-called top-handle type. However, it will be understood that the disclosure herein is equally applicable to rear-handle type chainsaws and other types of handheld battery-powered 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 that guides the saw chain 16 in a long loop. The cutting assembly extends in a longitudinal direction L from the 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 schematically in FIG. 1A by a dashed circle), and a finger-operated trigger 24 that enables 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 using the electric motor 22. The power tool 10 further includes a controller 26 (shown only schematically 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. Referring now to FIG. 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, providing structural support to various components. The power tool housing 13 includes a first housing portion 13a and a second housing portion 13b, which are firmly joined together.

[0029] 2B shows the connector 30 in more detail. The connector 30 is formed by a connector assembly 32 including a rigid connector body 34 having a pair of connector terminals 36. The connector terminals 36 are positioned 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 includes a rigid connector sheath 38 that surrounds the connector body 34 and forms a sleeve extending along the connection direction C (FIG. 2A).

[0030] FIG. 2C shows the connector assembly 32 in more detail. A set of connector terminals 36 includes a first current supply connector terminal 40a and a second current supply connector terminal 40b. The first current supply connector terminal 40a and the second current supply connector terminal 40b are each configured to engage 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 enables the exchange of control signals between the power tool 10 and the battery pack 20, for example, for power control, exchange of battery state information, etc.

[0031] FIG. 3 shows a side view of the battery pack 20 facing the electrical connector 30 of the power tool 10 in FIG. 2A. The battery pack 20 includes a plurality of rechargeable lithium-ion type battery cells (not shown) disposed within a battery housing 21. The battery pack 20 further includes an electrical connector 130. The electrical connector 130 is configured to supply power to the electric motor 22 (FIG. 1A) of the power tool 10 by being releasably coupled to an electrical connector that is a mating partner of the power tool 10, i.e., the electrical connector 30 (FIG. 2A) 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 includes respective rigid connector bodies 134 having a set of connector terminals 136. The connector terminals 136 are accessible from outside the housing 21 when the battery pack 20 is not connected to the power tool 10 (FIG. 1). A rigid connector sheath 138 is formed by the battery housing 21 and forms a sleeve that surrounds the connector body 134 and extends 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. The first current supply connector terminal 140a and the second current supply connector terminal 140b are each configured to mate with a corresponding first and second current supply connector terminal 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 series and parallel groups (not shown) to provide a combined voltage of approximately 36 V 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 comprises a plurality of rigidly interconnected parts 21a, 21b, and 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 portion 13b, via a resilient connector body support 48. The resilient connector body support 48 is configured as a rubber cushion pad disposed between the connector body 34 and the second housing portion 13b. Both the connector body support 48 and the connector body 34 are attached to a pair of screw fixing posts 50 integrally formed with the second housing portion 13b by a pair of mounting screws 52. One of the mounting screws 52 is shown. This resilient attachment allows the connector assembly 32 to automatically align with the mating connector during connection within the bending range permitted by the flexibility of the connector body support 48. In particular, the connector body support allows the rigid connector body 34 to flex 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 approximately 4 mm in the connection direction and allows the connector body 34 to resiliently move in the connection direction C with a maximum bending range of approximately 1 mm. The cushion pad 48 is integrally formed with the cable holder 54. The cable holder 54 includes cable retention holes 56 a, 56 b accessible from its edge. Thereby, the current supply cables 44 a, 44 b may be pressed into the respective holes 56 a, 56 b 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 a 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 held within a first hole 56a of a cable holder 54. The second current supply cable 44b is connected to the second current supply terminal 40b and held within 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 within the first hole 56a of the cable holder 54 and a second terminal temperature sensor 60b disposed within the second hole 56b of the cable holder 54. Thereby, 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 schematically shown in the view of FIG. 5B. However, it is understood that the printed circuit board 62 may be configured to be attached to the housing 13 (FIG. 2A), for example, by a screw 52 to sandwich the printed circuit board 62, for example, between the connector body 34 and the connector body support 48, or between the connector body support 48 and the second housing portion 13b.

[0035] The terminal temperature sensors 60a and 60b are connected to the control device 26 (FIG. 1A) in a manner not shown. The controller 26 is configured to set the 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 the power limit threshold temperature, for example, 60 degrees, the controller 26 restricts the power tool 10 to operate in the normal power mode of, for example, 2.2 kW. When the controller 26 determines that the temperature of the connector 30 (FIG. 2A) is less than the power limit release threshold temperature, for example, 50 degrees, the controller 26 permits the power tool 10 to operate in the high power mode of, for example, 2.7 kW. The display lamp 64 (FIG. 1B), which may include the message "Power boost available", lights up to inform the operator of the power tool that the power tool 10 is in the high power mode. By setting a power limit threshold temperature higher than the power limit release threshold temperature, the power tool 10 does not switch excessively between the normal mode and the high power mode.

[0036] The cross-sectional view of FIG. 6 shows the position of the connector assembly 32 within the housing 13 of the power tool 10. The screw 52 attaches the connector body 34 to the screw fixing post 50 on the inner surface of the second housing part 13b via the elastic connector body support 48. In FIG. 6, only the second and third housing parts 13b and 13c of the battery pack 20 are shown.

[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 resiliently bend 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 positioned along the current supply path formed by the first current supply wire at a distance D1 of approximately 15 mm from the first terminal engagement connection 70. The current supply wire also acts as a heat transfer wire so that the temperature at the first terminal engagement connection 70 is well represented by a reading from the first terminal temperature sensor 60a, which abuts the first current supply cable 44a at a distance D2 of approximately 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 mate 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 incorporated 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 illustrates a tool system 80 including the power tool 10 of FIG. 1A, a second handheld 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 first power tool 10 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 does not include a terminal temperature sensing device 58 (FIG. 5B). Without information about the connector temperature, the controller of the second power tool 810 is configured to enable only the normal power mode, independent of temperature changes in the electrical connector 830 of the second power tool 810. Meanwhile, the first power tool 10 may be configured to operate 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, and 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 hedge trimmer, a chainsaw and a clearing saw, etc.

[0043] FIG. 9 shows a method of controlling the hand-held battery-powered power tool 10 of FIG. 1A to obtain power from the battery pack 20. This method is implemented in a controller 26 having a processor and a 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-powered power tool 10 and the battery pack 20.

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

[0046] In step 903, the controller 26 determines whether the connector temperature is less than a 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 in which the power tool 10 can operate in the high power mode. The high power mode enables the power tool 10 to operate at a higher power than the normal power mode.

[0047] FIG. 10 shows a computer-readable storage medium implemented as a CD (compact disc) 99. The CD 99 stores a computer program product including instructions that, when executed on a processor, execute any of the above methods.

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

[0049] For example, the present invention has been described with reference to a rear handle type chainsaw. However, it is understood that the teachings herein are equally applicable to a top handle type chainsaw. The temperature sensor of the connector temperature sensing device need not be disposed in direct contact with the current supply cable and may be disposed at another suitable position 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 hand-held battery-powered electric tool, comprising: a working tool (16); an electric motor (22) configured to operate the working tool (16); a connector assembly (32) configured to be releasably coupled to a connector (130) which is a mating partner of a detachable and rechargeable battery pack (20) for supplying power to the electric motor (22); The hand-held battery-powered electric tool, wherein the connector assembly (32) includes a connector temperature sensing device (58) configured to sense the temperature of the connector assembly (32).

2. The connector assembly (32) includes a first current supply connector terminal (40a), The first current supply connector terminal (40a) is configured to engage with a first current supply connector terminal (140a) which is a mating partner of the connector (130) at a first terminal engagement connection portion (70). The hand-held battery-powered electric tool according to claim 1, wherein the connector temperature sensing device (58) includes a first terminal temperature sensor (60a) disposed less than 50 mm from the first terminal engagement connection portion (70).

3. The connector assembly (32) includes a first current supply cable (44a), The hand-held battery-powered electric tool according to claim 1, wherein the first terminal temperature sensor (60a) is disposed less than 8 mm from a conductor (66) of the first current supply cable (44a).

4. The connector assembly (32) includes a second current supply connector terminal (40b), The second current supply connector terminal (40b) is configured to engage with a second current supply connector terminal (140b) which is a mating partner of the connector (130) at a second terminal engagement connection portion (70). The hand-held battery-powered electric tool according to claim 2, wherein the connector temperature sensing device (58) includes a second terminal temperature sensor (60b) disposed less than 50 mm from the second terminal engagement connection portion (70).

5. The hand-held battery-powered electric tool according to claim 1, wherein the connector temperature sensing device (58) includes a printed circuit board (62) and two or more temperature sensors (60a, 60b) coupled to the printed circuit board (62).

6. The connector assembly (32) includes a cable holder (54) provided with one or more holes (56a, 56b), each of the one or more holes (56a, 56b) is configured to at least partially surround and hold a respective current supply cable (44a, 44b), The hand-held battery-powered power tool according to claim 1, wherein the connector temperature sensing device (58) includes one or more temperature sensors (60a, 60b) disposed in the one or more holes (56a, 56b).

7. further comprising a rigid body portion frame (13), the connector assembly (32) includes a rigid connector body (34) and an elastic connector body support (48), The hand-held battery-powered power tool according to claim 1, wherein the rigid connector body (34) is attached to the rigid body portion frame (13) via the elastic connector body support (48).

8. The connector (130) as the mating connector is configured to be coupled to the connector assembly (32) along a connection direction (C), The hand-held battery-powered power tool according to claim 7, wherein the elastic connector body support (48) is configured to allow the rigid connector body (34) to move elastically in the connection direction (C).

9. The hand-held battery-powered power tool according to claim 8, wherein the elastic connector body support (48) is configured as a cushion pad sandwiched between the rigid connector body (34) and the rigid body portion frame (13).

10. The hand-held battery-powered power tool according to claim 9, wherein the cushion pad (48) has a thickness (T) of 2 mm to 10 mm in the connection direction.

11. The hand-held battery-powered power tool according to claim 9, wherein the cushion pad (48) is integrally formed with the cable holder (54).

12. The hand-held battery-powered power tool according to claim 1, further comprising a controller (26) configured to set an upper limit of power obtainable from the battery pack (20) based on a sensor signal from the connector temperature sensing device (58).

13. A tool system a first hand-held battery-powered power tool (10), a second hand-held battery-powered power tool (810), A detachable and rechargeable battery pack (20) configured to be alternately coupled to the first hand-held battery-powered power tool (10) and the second hand-held battery-powered power tool (810). The second hand-held battery-powered power tool (810) has a power upper limit that can be obtained from the battery pack (20). The power upper limit is independent of the temperature of the electrical coupling connection between the battery pack (20) and the second hand-held battery-powered power tool (810). The first hand-held battery-powered power tool (10) is the hand-held battery-powered power tool (10) according to claim 12. The power upper limit of the first hand-held battery-powered power tool (10) may be set to a value higher than the power upper limit of the second hand-held battery-powered power tool (810). Tool system.

14. A method for controlling a hand-held battery-powered power tool (10) to obtain power from a battery pack (20), comprising Sensing the temperature of the connector of the electrical coupling connection (70) between the hand-held battery-powered power tool (10) and the battery pack (20); Enabling the hand-held battery-powered power tool (10) to operate in a normal power mode in response to a determination that the temperature of the connector exceeds a power limit threshold temperature; Enabling the hand-held battery-powered power tool (10) to operate in a high power mode in response to a determination that the temperature of the connector is less than a power limit release threshold temperature, the high power mode being capable of operating the hand-held battery-powered power tool (10) at a power higher than the normal power mode. A method comprising the steps of.

15. A data processing device (26) comprising one or more processors and a memory configured to execute the method according to claim 14.

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