Cutting tool

Abstract

To provide a technology which enables improvement of users' convenience in a cutting tool provided with a hand guard.SOLUTION: A cutting tool disclosed by the specification includes: a cutting unit; a prime mover configured to drive the cutting unit; a housing including a housing body for holding the cutting unit and housing the prime mover, and a grip which extends from the housing body and is configured to be grasped by a user's hand; and a hand guard attached to the housing, configured to protect fingers of the user's hand grasping the grip, and being more deformable than the housing.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology disclosed in this specification relates to cutting tools.

Background Art

[0002] Patent Document 1 discloses a cutting tool including a cutting working part, a prime mover that drives the cutting working part, a housing body that holds the cutting working part and houses the prime mover, and a grip that extends from the housing body and is gripped by a user's hand. A finger guard part is attached to the housing and protects the user's fingers in the state where the grip is gripped. The finger guard part is integrally formed with the housing without a joint. Therefore, the ease of deformation of the finger guard part is about the same as that of the housing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the cutting tool of Patent Document 1, a finger guard part (corresponding to the hand guard in this application) is provided to protect the user's fingers in the state where the grip is gripped. However, in a cutting tool, providing a hand guard may impair the convenience of the user. For example, when a user performs a cutting operation (e.g., pruning operation of a tree branch) using a cutting tool, the hand guard may mechanically interfere with an obstacle (e.g., a tree trunk), making it impossible to set the cutting tool in a desired position or posture, which may hinder the cutting operation. In this specification, a technology capable of improving the convenience of the user in a cutting tool provided with a hand guard is provided.

Means for Solving the Problems

[0005] A cutting tool disclosed herein comprises a housing including a cutting workpiece, a prime mover for driving the cutting workpiece, a housing body for holding the cutting workpiece and housing the prime mover, and a grip extending from the housing body and grasped by the user's hand; and a handguard attached to the housing and more deformable than the housing for protecting the user's fingers when the grip is grasped. In this specification, "deformation of the handguard" means reversible deformation. For example, "deformation of the handguard" may mean elastic deformation of the handguard itself. Also, in a handguard provided like a so-called swing door, "deformation of the handguard" may mean that the handguard swings and deforms from a closed state to an open state. Also, in a handguard provided so as to be translationally movable between a first position and a second position relative to the housing, "deformation of the handguard" may mean that the position of the handguard relative to the housing changes.

[0006] According to the above configuration, when the handguard is in contact with an obstacle and a load is applied to the handguard, the handguard deforms relative to the housing. Therefore, when a user performs cutting work with a cutting tool, even if the handguard interferes with an obstacle, the cutting tool can be positioned and rotated as desired. Thus, user convenience can be improved with a cutting tool equipped with a handguard. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view of the chainsaw T1 according to Example 1, taken from the front left and above. [Figure 2] This is a perspective view of the chainsaw T1 according to Example 1, with the battery pack B1 removed from the battery interface 160, as seen from the rear right upper side. [Figure 3] This is a bottom view of the chainsaw T1 according to Example 1, seen from below. [Figure 4]This is a perspective view of the chainsaw T1 according to Embodiment 1, with the sprocket cover 18 removed from the housing body 14, as seen from the rear left upper. [Figure 5] This is a cross-sectional view from the left of the internal structure near the base end of the grip 16 of the chainsaw T1 according to Example 1. [Figure 6] This is a cross-sectional view of the internal structure of the housing 4 of the chainsaw T1 according to Example 1, viewed from the right. [Figure 7] This is a view of the chainsaw T1 according to Embodiment 1, showing the electric motor 64, motor shaft 80, cooling fan 82, power transmission mechanism 70, oil pump 68, sprocket 26, and working section 10, as seen from the front right and above. [Figure 8] This is a view of the inside of the housing body 14 of the chainsaw T1 according to Embodiment 1, seen from the front along a direction perpendicular to the axis A1 of the motor shaft 80. [Figure 9] This is a perspective view of the chainsaw T2 according to Example 2, with the battery pack B2 removed from the battery interface 160, as seen from the rear right upper side. [Figure 10] This is a cross-sectional view of the internal structure of the housing 4 of the chainsaw T2 according to Example 2, viewed from the right. [Figure 11] This is a perspective view of the chainsaw T3 according to Example 3, with the battery pack B3 removed from the battery interface 360, as seen from the rear right upper side. [Figure 12] This is a cross-sectional view of the internal structure of the housing 4 of the chainsaw T3 according to Example 3, viewed from the right. [Figure 13] This is a perspective view of the chainsaw T4 according to Example 4, with the battery pack B4 removed from the battery interface 360, as seen from the rear right upper side. [Figure 14] This is a cross-sectional view of the internal structure of the housing 4 of the chainsaw T4 according to Embodiment 4, viewed from the right. [Figure 15]This is a perspective view of the modified chainsaw T1, with the battery pack B1 removed from the battery interface 160, taken from the rear right upper side. [Modes for carrying out the invention]

[0008] Representative and non-limiting examples of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to show those skilled in the art details for carrying out preferred examples of the present invention and is not intended to limit the scope of the invention. Furthermore, the disclosed additional features and inventions may be used separately from or in conjunction with other features and inventions to provide a further improved cutting tool.

[0009] Furthermore, the combinations of features and processes disclosed in the following detailed description are not essential for carrying out the present invention in the broadest sense, and are described solely to illustrate representative examples of the present invention. Moreover, the various features of the following representative examples, as well as the various features described in the claims, do not necessarily have to be combined in the same way as the examples described herein, or in the order listed, to provide additional and useful embodiments of the present invention.

[0010] All features described herein and / or in the claims are intended to be disclosed individually and independently of each other, as limitations to the specific matters described in the original disclosure and in the claims, separate from the features described in the examples and / or in the claims. Furthermore, all descriptions of numerical ranges and groups or clusters are intended to disclose intermediate configurations as limitations to the specific matters described in the original disclosure and in the claims.

[0011] In one or more embodiments, the housing may be formed of a material having a Young's modulus greater than 100 MPa. The hand guard may be formed of a material having a Young's modulus within the range of 1 MPa to 100 MPa.

[0012] When the hand guard is deformed by elastic deformation, the greater the Young's modulus of the material used for the hand guard, the greater the load required to deform the hand guard by a predetermined amount. According to the above configuration, the user can sufficiently deform the hand guard with a relatively small load. Therefore, the convenience of the user can be further improved.

[0013] In one or more embodiments, the housing may be formed of a plastic material. The hand guard may be formed of a rubber material.

[0014] The rubber material can be elastically deformed more greatly than other materials (for example, plastic materials). According to the above configuration, the user can elastically deform the hand guard greatly. Therefore, the convenience of the user can be further improved.

[0015] In one or more embodiments, the hand guard may include a first end portion disposed near the proximal end of the grip, a second end portion disposed near the distal end of the grip, and a guard body continuously extending between the first end portion and the second end portion. In this specification, in the grip, the end portion closer to the housing body is referred to as the "proximal end of the grip", and the end portion farther from the housing body is referred to as the "distal end of the grip".

[0016] According to the above configuration, the hand guard is disposed so as to cover from the proximal end to the distal end of the grip. Therefore, the fingers of the user in the state of gripping the grip can be reliably protected.

[0017] In one or more embodiments, the housing may further include a first mounting portion to which the first end of the handguard is attached, and a second mounting portion to which the second end of the handguard is attached. At least one of the first end and the second end may be rotatably mounted to at least one of the corresponding first and second mounting portions.

[0018] When the handguard is supported by the housing at two points, a first end and a second end, both the first and second ends may be fixed to corresponding first and second mounting points. In this case, the handguard can be considered a beam fixed at both ends, so the load required to deform the handguard (guard body) by a predetermined amount becomes large. In contrast, according to the above configuration, at least one of the first and second ends is rotatably attached to at least one of the corresponding first and second mounting points. In this case, the handguard can be considered a beam fixed at one end and simply supported (pinned) at the other end, or a beam simply supported (pinned) at both ends, so the user can sufficiently deform the handguard with a relatively small load.

[0019] In one or more embodiments, the guard body may include a plate portion formed in the shape of a plate.

[0020] According to the above configuration, by making the plate section thin and spreading out, the plate section can be made more elastically deformable, and the plate section can protect the user's fingers over a wide area. Therefore, it is possible to create a handguard that is easily deformable while ensuring the protective function of the handguard.

[0021] In one or more embodiments, the guard body may include ribs that protrude from the surface of the plate portion at a position opposite to the grip and that extend in a direction toward the second end.

[0022] If the plate portion deforms excessively at the position opposite the grip (the amount of deflection of the plate portion becomes excessive), the gap between the grip and the plate portion becomes excessively narrow, and there is a risk that the plate portion will be pressed against the fingers of the user gripping the grip. In this case, it becomes difficult for the user to change the position of their fingers, thus compromising user convenience. With the above configuration, the rigidity of the plate portion at the position opposite the grip is increased by the rib portion. Therefore, excessive deformation of the plate portion at the position opposite the grip (excessive deflection of the plate portion) can be suppressed. Therefore, the pressing of the plate portion against the fingers of the user gripping the grip can be suppressed. Consequently, user convenience can be improved.

[0023] In one or more embodiments, the rib portion may protrude from the surface of the plate portion opposite to the surface facing the grip.

[0024] If the ribs protrude from the surface of the plate facing the grip, there is a possibility that the ribs may come into contact with the user's fingers when inserting or removing them between the grip and the plate. In this case, it may cause inconvenience to the user and thus impair user convenience. In contrast, with the above configuration, the ribs protrude from the surface of the plate opposite to the surface facing the grip. Therefore, it is possible to suppress the ribs coming into contact with the user's fingers when inserting or removing them between the grip and the plate. Thus, user convenience can be improved.

[0025] In one or more embodiments, the cutting tool may further include a trigger lever provided near the base end of the grip, which activates the motor when pulled toward the grip by the user's fingers. The guard body may include a first extension connected to the first end and extending away from the grip from the base end toward the tip end, a second extension connected to the second end and extending away from the grip from the tip end toward the base end, and a bend connecting the first and second extensions. The length of the first extension may be shorter than the length of the second extension.

[0026] When the guard body deforms, if it presses against the user's fingers while they are on the trigger lever, it may cause accidental operation of the trigger lever. In contrast, with the above configuration, the guard body has increased rigidity near the bent portion. Furthermore, the bent portion is shaped to protrude outward when viewed from the grip. As a result, when the guard body is pressed against the grip, the bent portion creates space between the grip and the guard body. Also, since the bent portion is located closer to the base end of the grip, space is created near the trigger lever when the guard body is pressed against the grip. Therefore, with the above configuration, it is possible to suppress the guard body from pressing against the user's fingers while they are on the trigger lever, thereby suppressing accidental operation of the trigger lever.

[0027] (Example 1) As shown in Figure 1, the cutting tool in this embodiment is a chainsaw T1. The chainsaw T1 is a so-called pruning chainsaw, mainly used for cutting wood and tree branches. The chainsaw T1 is relatively lightweight, weighing at most about 2000g. As a result, the chainsaw T1 can be carried with one hand.

[0028] The chainsaw T1 comprises a housing 4, a guide bar 6, a saw chain 8, a handguard 20, and a battery pack B1. The guide bar 6 is an elongated, plate-shaped member attached to the housing 4 so as to protrude forward from the housing 4. The guide bar 6 is made of a metal material such as iron. The saw chain 8 has multiple interconnected cutters (not shown) and is attached along the periphery of the guide bar 6. A roughly rectangular battery pack B1 is attached to the housing 4. The chainsaw T1 uses power supplied from the battery pack B1 to move the saw chain 8 along the periphery of the guide bar 6.

[0029] Various guide bars 6 can be attached depending on the type of cutting work. The radius of curvature of the tip of the guide bar 6 is, for example, 15 mm. In this embodiment, the chainsaw T1 moves the saw chain 8 along the periphery of the guide bar 6 at a speed of, for example, 8 m / s. In this specification, the guide bar 6 and the saw chain 8 are sometimes collectively referred to as the "working section 10". In this embodiment, the weight of the working section 10 is, for example, about 180 g. The housing 4 is also provided with a working cover 12 that covers a part of the working section 10. Therefore, the user performs the cutting work by pressing the part of the working section 10 that is not covered by the working cover 12 against the object to be cut (for example, a tree branch). At this time, it is assumed that the load that the user applies to the chainsaw T1 is at most about 20 N.

[0030] In the following explanation, along the longitudinal direction of the guide bar 6, the direction from the housing 4 toward the guide bar 6 is defined as the forward direction, and the direction from the guide bar 6 toward the housing 4 is defined as the rearward direction. Furthermore, the direction perpendicular to the front-rear direction, from the work section 10 toward the work cover 12, is defined as the upward direction, and the direction toward the work cover 12 toward the work section 10 is defined as the downward direction. Finally, the direction perpendicular to both the front-rear and up-down directions is defined as the left-right direction. Note that in Figures 1 to 15, for the sake of simplicity, the saw chain 8 is shown as a ring-shaped member flush with the guide bar 6.

[0031] The housing 4 comprises a housing body 14, a grip 16, a first mounting portion 22, and a second mounting portion 24. The housing body 14 has a substantially rectangular parallelepiped shape, inclined from bottom to top as it moves from front to rear in the front-rear direction. The housing body 14 holds the work section 10 together with the sprocket cover 18 at the front. The grip 16 is connected to the front lower part of the housing body 14. The grip 16 has a substantially cylindrical shape, inclined from top to bottom as it moves from front to rear in the front-rear direction. The first mounting portion 22 is provided projecting downward from the housing 4 and is located near the base end of the grip 16. The second mounting portion 24 is provided projecting downward from the housing 4 and is located near the tip of the grip 16. The handguard 20 is attached to the first mounting portion 22 and the second mounting portion 24. The housing 4 (housing body 14, grip 16, first mounting portion 22, and second mounting portion 24) is made of a material with a Young's modulus greater than 100 MPa. In this embodiment, the housing 4 is made of a plastic material such as polyamide. The Young's modulus of polyamide may vary depending on the surrounding environment, but it can be said to be greater than at least 5000 MPa. The parts where the user's fingers are placed (the head 14a of the housing body 14 and the area around the grip 16) are coated with a rubber material such as nitrile butadiene rubber.

[0032] The battery pack B1 houses a rechargeable secondary battery, such as a lithium-ion battery. The output voltage of the battery pack B1 is, for example, 10V. The battery capacity of the battery pack B1 is, for example, 1.5Ah. The weight of the battery pack B1 is, for example, approximately 215g. As shown in Figure 3, a display unit 166 is provided on the bottom surface of the battery pack B1. The display unit 166 informs the user of the remaining battery level of the battery pack B1 by changing the display according to the remaining battery level of the battery pack B1.

[0033] As shown in Figure 2, the tip of the grip 16 is provided with a battery interface 160 for detachably receiving the battery pack B1. The battery pack B1 is attached to the battery interface 160 by sliding it from the rear upper to the front lower. The battery interface 160 also has a connection terminal 162 for connecting to the terminals (not shown) of the battery pack B1. The connection terminal 162 is electrically connected to the control unit 62 (see Figure 6) and the trigger switch 52 (see Figure 6), which will be described later. When the battery pack B1 is attached to the battery interface 160, the terminals of the battery pack B1 and the connection terminal 162 are electrically connected. This allows power to be supplied from the battery pack B1 to the control unit 62 and the trigger switch 52.

[0034] As shown in Figure 1, when the battery pack B1 is attached to the battery interface 160, the outer surfaces of the battery pack B1 and the grip 16 are smoothly connected. The battery pack B1 can be removed by pressing in the hook 164 provided on the battery pack B1 and sliding it from the front-down to the rear-up relative to the battery interface 160.

[0035] As shown in Figure 4, the sprocket cover 18 comprises a sprocket cover body 36 and a locking member 42. The sprocket cover body 36 includes a sleeve 38. The locking member 42 includes a locking member body 44, a nut 46, and a claw portion 48. Inside the sprocket cover 18, the sprocket 26 is exposed to the outside of the housing body 14. A saw chain 8 is stretched across the sprocket 26 from the guide bar 6. The guide bar 6 also has a notch 6a that extends along the front-rear direction. Pins 28, 30 and bolts 32, which are fixed protruding from the left side of the housing body 14, are inserted into the notch 6a from the right side.

[0036] From the state shown in Figure 4, the sprocket cover 18 can be attached to the housing body 14 by inserting a bolt 32 into the sleeve 38 of the sprocket cover body 36 and fastening a nut 46 of the locking member 42 to the bolt 32 that passes through the sleeve 38. With the nut 46 fastened to the bolt 32, the guide bar 6 is sandwiched and fixed between the housing body 14 and the sprocket cover 18. The user can adjust the tension of the saw chain 8 by changing the distance between the guide bar 6 and the sprocket 26 by sliding the guide bar 6 in the front-back direction relative to the housing body 14 with the bolt 32 and nut 46 loosened.

[0037] The user can tighten or loosen the bolt 32 and nut 46 by rotating the claw portion 48, which is positioned to the left of the locking member body 44, around the axis of the bolt 32. This allows the user to fasten the nut 46 to the bolt 32 with sufficient tightening torque without using any special tools. As shown in Figure 1, the claw portion 48 is normally held in a reclined position along the locking member body 44 by a torsion spring (not shown).

[0038] As shown in Figure 2, a trigger lever 50 for the user to drive the workpiece 10 is located on the lower surface near the base end of the grip 16. As shown in Figure 5, the trigger lever 50 is supported by the housing 4 so as to be rotatable around a pivot axis 50a that extends in the left-right direction. The user can pull up the trigger lever 50 toward the grip 16. In this specification, the front end of the portion of the trigger lever 50 that is exposed to the outside of the grip 16 is simply referred to as the "front end 50f". The rear end of the portion of the trigger lever 50 that is exposed to the outside of the grip 16 is simply referred to as the "rear end 50r".

[0039] Inside the housing 4 is a trigger switch 52 that detects the user's operation of pulling up the trigger lever 50. The trigger switch 52 is located directly above the trigger lever 50 and straddles the space between the grip 16 and the housing body 14. The trigger switch 52 is electrically connected to a control unit 62 (see Figure 6), which will be described later. The trigger switch 52 outputs a trigger-on signal to the control unit 62 while the trigger lever 50 is being pulled up. The housing 4 also contains a locking member 54 that switches between a state that allows and prohibits the user from operating the trigger lever 50. The locking member 54 is located directly above the trigger lever 50 and in front of the trigger switch 52. The locking member 54 is supported by the housing 4 so as to be rotatable around a pivot axis 54a that extends in the left-right direction.

[0040] When the locking member 54 is rotated upward, it mechanically interferes with the trigger lever 50, preventing the trigger lever 50 from rotating upward. When the locking member 54 is rotated downward, it no longer interferes with the trigger lever 50, allowing the trigger lever 50 to rotate upward.

[0041] As shown in Figure 1, the locking member 54 includes a left-side locking lever 58a that protrudes to the outside of the housing 4 through a through-hole 56a provided on the left side of the housing 4. As shown in Figure 2, the locking member 54 also includes a right-side locking lever 58b that protrudes to the outside of the housing 4 through a through-hole 56b provided on the right side of the housing 4. Hereinafter, the left-side locking lever 58a and the right-side locking lever 58b will be collectively referred to as "locking lever 58". The user can rotate the locking member 54 via the locking lever 58.

[0042] The trigger lever 50 and the locking member 54 are connected to each other by a torsion spring 60 (see Figure 5). The torsion spring 60 biases the trigger lever 50 to rotate downward and the locking member 54 to rotate upward. Therefore, when the user releases their hand from the trigger lever 50, the trigger lever 50 is rotated downward due to the biasing force of the torsion spring 60. Also, when the user releases their hand from the locking lever 58, the locking member 54 is rotated upward due to the biasing force of the torsion spring 60.

[0043] For example, when using the chainsaw T1, the user holds the chainsaw T1 by gripping the grip 16 with their right hand and resting their left hand on the head 14a. From this position, when the user pushes down the lock lever 58 with their right thumb, the user is allowed to operate the trigger lever 50. In this state, the user pulls up the trigger lever 50 with their right index finger, which drives the work unit 10.

[0044] (Handguard 20 configuration) The handguard 20 shown in Figure 1 is a protective device for protecting the user's hand when gripping the grip 16. If the saw chain 8 breaks while the user is performing a cutting operation (while the work unit 10 is running), the broken saw chain 8 may fly out from the guide bar 6 while maintaining its momentum. In such a case, the handguard 20 can prevent the saw chain 8 that has flown out from the guide bar 6 from coming into contact with the user's hand gripping the grip 16 (see Figure 1). For example, the handguard 20 is made of a material with a Young's modulus in the range of 1 MPa to 100 MPa. In this embodiment, the handguard 20 is made of a rubber material such as nitrile butadiene rubber. The Young's modulus of nitrile butadiene rubber may vary depending on the surrounding environment, but it can be said to be in the range of 1 MPa to 10 MPa.

[0045] The handguard 20 comprises a first end 202, a second end 204, and a guard body 206 that extends continuously between the first end 202 and the second end 204. The first end 202 is attached to a first mounting portion 22 so as to be rotatable around a pivot axis 22a extending in the left-right direction. By being attached to the first mounting portion 22, the first end 202 is positioned near the base end of the grip 16. The second end 204 is attached to a second mounting portion 24 so as to be rotatable around a pivot axis 24a (see Figure 2) extending in the left-right direction. By being attached to the second mounting portion 24, the second end 204 is positioned near the tip of the grip 16.

[0046] The guard body 206 comprises a plate portion 208 formed in a plate shape and a plurality of rib portions 210 (see Figure 3) protruding downward from the lower surface of the plate portion 208. The plate portion 208 is positioned so that its upper surface faces the grip 16. In this embodiment, the thickness of the plate portion 208 (thickness in the direction perpendicular to the upper and lower surfaces of the plate portion 208) is, for example, about 5 mm.

[0047] As shown in Figure 3, when the chainsaw T1 is viewed from below, the plate portion 208 has a roughly rectangular shape. The plate portion 208 has a width of approximately 29 mm to the left of the left side of the guide bar 6. The plate portion 208 has a width of approximately 30 mm to the right of the right side of the guide bar 6. The plate portion 208 also has a width of approximately 30 mm to the left of the left side of the grip 16 (see Figure 1). The plate portion 208 has a width of approximately 0.5 mm to the right of the right side of the grip 16.

[0048] The multiple rib sections 210 include a first rib section 212 extending in the front-rear direction along the lower surface of the plate section 208, a second rib section 214 extending in the left-right direction along the lower surface of the plate section 208, and a third rib section 216 extending along the peripheral edge of the lower surface of the plate section 208. There are four first rib sections 212 arranged in the left-right direction. When the chainsaw T1 is viewed from below, each of the first rib sections 212 extends in a substantially straight line between the first end 202 and the second end 204. There are also three second rib sections 214 arranged in the front-rear direction. The first rib sections 212 and the second rib sections 214 are connected at mutually perpendicular points. The second rib sections 214 are connected to the third rib section 216 at their left and right ends.

[0049] As shown in Figure 6, the plate portion 208 is composed of a first extension portion 220 that extends away from the grip 16 as it moves from the base end towards the tip end, a second extension portion 222 that extends away from the grip 16 as it moves from the tip end towards the base end, and a bent portion 224 that connects the first extension portion 220 and the second extension portion 222. The length of the first extension portion 220 in the extension direction is shorter than the length of the second extension portion 222 in the extension direction. The bending angle of the bent portion 224 is, for example, 100°. The radius of curvature of the bent portion 224 is, for example, 18 mm. As a result, in its natural state (when no external force is applied to the handguard 20), the handguard 20 has a shape that protrudes outward when viewed from the grip 16.

[0050] In the handguard 20 configured as described above, the handguard 20 is more elastically deformable than the housing 4. The handguard 20 is configured to begin to deform when a predetermined load of 5N or less is applied, for example, from a direction opposite to the lower surface of the plate portion 208. Here, "beginning to deform" means that the elastic strain of the handguard 20 exceeds 1%. Therefore, the user can deform the handguard 20 with a relatively small load.

[0051] (Internal structure of the T1 chainsaw) As shown in Figure 6, the housing body 14 contains a control unit 62, an electric motor 64, an oil tank 66, an oil pump 68, a reduction gear 72, and a cooling fan 82.

[0052] As shown in Figure 7, the electric motor 64 is an inner-rotor type DC brushless motor. The electric motor 64 comprises a stator 76 around which a coil 74 is wound, and a rotor 78 located inside the stator 76 and equipped with permanent magnets (not shown). In this embodiment, the weight of the electric motor 64 (coil 74, stator 76, and rotor 78) is, for example, approximately 180g. A motor shaft 80 is fixed to the rotor 78, positioned to pass through the center of both the stator 76 and the rotor 78. Therefore, the electric motor 64 is configured to rotate the motor shaft 80.

[0053] The cooling fan 82 is fixed to the motor shaft 80 below the rotor 78. The cooling fan 82 rotates in conjunction with the rotation of the motor shaft 80. When the cooling fan 82 rotates, an airflow is formed that moves from bottom to top along the axis A1 of the motor shaft 80 (see Figure 6). At this time, air is drawn in from the outside to the inside of the housing 4 through the left intake port 140 (see Figure 1) and the right intake port 142 (see Figure 2). Also, air is discharged from the inside to the outside of the housing 4 through the left exhaust port 144 (see Figure 1) and the right exhaust port 146 (see Figure 2). As a result, the cooling fan 82 can cool the electric motor 64 in conjunction with the driving of the electric motor 64.

[0054] The reduction gear 72 includes a first bevel gear 72a fixed to the motor shaft 80 below the cooling fan 82, and a second bevel gear 72b that meshes with the first bevel gear 72a. The second bevel gear 72b is fixed to the drive shaft 84. The drive shaft 84 is supported by the housing 4 (see Figure 1) so as to be rotatable around a rotation axis that extends in the left-right direction. A sprocket 26 is fixed to the drive shaft 84 to the left of the second bevel gear 72b. Therefore, when the electric motor 64 is driven, the rotational motion of the motor shaft 80 is transmitted to the saw chain 8 via the reduction gear 72, the drive shaft 84, and the sprocket 26. This causes the saw chain 8 to rotate around the sprocket 26 and the guide bar 6.

[0055] The oil tank 66 shown in Figure 6 is a tank for storing lubricating oil to lubricate the saw chain 8. The oil tank 66 can store a maximum of approximately 50cc of lubricating oil. The oil tank 66 is provided with an oil filler port (not shown) for replenishing the oil. A cap 660 is detachably attached to the oil filler port. The oil tank 66 is located near the front end of the housing body 14. As shown in Figure 2, the cap 660 and oil filler port of the oil tank 66 are exposed to the outside of the housing body 14. Therefore, the user can replenish the oil tank 66 by removing the cap 660 from the oil filler port without disassembling the housing body 14.

[0056] As shown in Figure 7, a worm gear 84a is fixed to the drive shaft 84 to the right of the second bevel gear 72b. The worm gear 84a meshes with the worm wheel 68a of the oil pump 68. Therefore, when the electric motor 64 is driven, the rotational motion of the motor shaft 80 is transmitted to the oil pump 68 via the reduction gear 72, drive shaft 84, worm gear 84a, and worm wheel 68a. This drives the oil pump 68. When the oil pump 68 is driven, lubricating oil is drawn into the oil supply passage 682 via the suction section 680 located inside the oil tank 66 (see Figure 6). Then, lubricating oil is supplied from the oil supply passage 682 to the guide bar 6 and saw chain 8 via the discharge section 684.

[0057] In this specification, the mechanism consisting of the reduction gear 72, the drive shaft 84, and the worm gear 84a may be referred to as the "power transmission mechanism 70". As shown in Figure 6, the power transmission mechanism 70 is located in the central part of the housing body 14. The power transmission mechanism 70 is located in front of and below the electric motor 64. The power transmission mechanism 70 is located behind the oil tank 66. In this embodiment, the weight of the power transmission mechanism 70 is, for example, approximately 110 g.

[0058] The control unit 62 is located directly below the top 14a of the housing body 14. The control unit 62 is located above and behind the electric motor 64. Below the control unit 62 and behind the electric motor 64, a wiring space S is formed. Although not shown, most of the conductors that electrically connect the various components such as the control unit 62 and the electric motor 64 are routed through the wiring space S.

[0059] The control unit 62 includes a control board (not shown) equipped with an inverter circuit having multiple switching elements and a control circuit that controls the operation of each switching element, and a roughly rectangular controller case 620 that houses the control board. The controller case 620 is made of a metal material such as aluminum. In this embodiment, the weight of the control unit 62 is, for example, about 60g.

[0060] The control unit 62 converts the DC power supplied from the battery pack B1 into three-phase AC power and supplies it to the electric motor 64 while the trigger switch 52 outputs a trigger-on signal. When the trigger switch 52 stops outputting a trigger-on signal, the control unit 62 cuts off the power supply from the battery pack B1 to the electric motor 64. The control unit 62 also controls the drive of the electric motor 64 so that the saw chain 8 travels in a predetermined direction. The predetermined direction of travel is such that the saw chain 8 travels forward when above the guide bar 6 and backward when below the guide bar 6.

[0061] (Positional relationship of main components with respect to axis A1) The axis A1 of the motor shaft 80 (see Figure 7) is located on a plane that extends in the front-rear and up-down directions. The axis A1 is inclined in the up-down direction, from rear to front as it moves from top to bottom. In this embodiment, the inclination angle of the axis A1 with respect to the up-down direction is 41°. The control unit 62 is located on axis A1. The control unit 62 (controller case 620) is located along a plane that is approximately perpendicular to axis A1. The distance from axis A1 to the front end 62f of the control unit 62 (coinciding with the front end of the controller case 620) is smaller than the distance from axis A1 to the rear end 62r of the control unit 62 (coinciding with the rear end of the controller case 620). In addition, the drive shaft 84 of the power transmission mechanism 70 is located approximately perpendicular to axis A1.

[0062] As shown in Figure 8, when viewing the inside of the housing body 14 (see Figure 1) from the front along a direction perpendicular to axis A1, the control unit 62, electric motor 64, cooling fan 82, power transmission mechanism 70 and sprocket 26, and oil tank 66 are arranged in approximately a straight line from top to bottom. When viewed from the front along a direction perpendicular to axis A1, the center of gravity 62G of the control unit 62, the center of gravity 64G of the electric motor 64, and the center of gravity 82G of the cooling fan 82 are all located on axis A1.

[0063] When viewed from the front along a direction perpendicular to axis A1, the control unit 62, the electric motor 64, and the cooling fan 82 each have a shape that is approximately symmetrical (approximately symmetrical with respect to axis A1). Although not shown, the grip 16 (see Figure 1) and the battery pack B1 (see Figure 1) also have a shape that is approximately symmetrical (approximately symmetrical with respect to axis A1). The sprocket 26 is positioned to the left of axis A1. The oil tank 66, oil pump 68, second bevel gear 72b, and worm gear 84a are positioned to the right of axis A1.

[0064] (Positional relationship of main components with respect to the trigger lever 50) Figure 6 illustrates a straight line A2 that passes through the front end 50f of the trigger lever 50 and extends vertically, and a straight line A3 that passes through the rear end 50r of the trigger lever 50 and extends vertically.

[0065] The front end 62f of the control unit 62 is located behind the rear end 50r of the trigger lever 50. The front end 64f of the electric motor 64 is located behind the front end 50f of the trigger lever 50 and in front of the rear end 50r of the trigger lever 50. The rear end 70r of the power transmission mechanism 70 (coinciding with the rear end of the first bevel gear 72a) is located behind the front end 50f of the trigger lever 50 and in front of the rear end 50r of the trigger lever 50. The front end B1f of the battery pack B1 is located behind the rear end 50r of the trigger lever 50. Also, the center of gravity position 62G of the control unit 62 is located behind the rear end 50r of the trigger lever 50. The center of gravity position 64G of the electric motor 64 is located behind the rear end 50r of the trigger lever 50. The center of gravity position 82G of the cooling fan 82 is located behind the front end 50f of the trigger lever 50 and in front of the rear end 50r of the trigger lever 50. The center of gravity BG1 of the battery pack B1 is located behind the rear end 50r of the trigger lever 50.

[0066] In the chainsaw T1 configured as described above, the center of gravity TG1 of the chainsaw T1 is located inside the housing 4, between straight lines A2 and A3. It can also be said that the center of gravity TG1 is located in a position that coincides with the locking member 54. Furthermore, the distance from straight line A2 to the center of gravity TG1 and the distance from straight line A3 to the center of gravity TG1 are approximately the same. In this embodiment, the center of gravity TG1 is determined with the oil tank 66 full of lubricating oil, the battery pack B1 attached to the battery interface 160, and all other components attached.

[0067] (Example 2) As shown in Figure 9, the cutting tool in this embodiment is a chainsaw T2. The chainsaw T2 has substantially the same configuration as the chainsaw T1 of Embodiment 1, except that it is equipped with a battery pack B2 instead of a battery pack B1. Below, only the differences between the chainsaw T2 and the chainsaw T1 will be described.

[0068] Battery pack B2 houses a rechargeable secondary battery, such as a lithium-ion battery. The output voltage of battery pack B2 is, for example, 10V. The battery capacity of battery pack B2 is, for example, 4.0Ah. The weight of battery pack B2 is, for example, approximately 375g. Battery pack B2 is detachably attached to the battery interface 160, similar to battery pack B1.

[0069] Compared to battery pack B1 (see Figure 2), battery pack B2 has a larger width in the direction in which the grip 16 extends. The width of battery pack B2 in the left-right direction is about the same as that of battery pack B1. The width of battery pack B2 in the direction perpendicular to the direction in which the grip 16 extends and the left-right direction is about the same as that of battery pack B1. As a result, the volume of battery pack B2 is larger than that of battery pack B1.

[0070] As shown in Figure 10, the front end B2f and center of gravity BG2 of the battery pack B2 are located behind the rear end 50r of the trigger lever 50. Furthermore, the center of gravity TG2 of the chainsaw T2 is located inside the housing 4, between straight lines A2 and A3. It can also be said that the center of gravity TG2 is located near the front end of the trigger switch 52. Additionally, the distance from straight line A2 to the center of gravity TG2 is greater than the distance from straight line A3 to the center of gravity TG2.

[0071] (Example 3) As shown in Figure 11, the cutting tool in this embodiment is a chainsaw T3. The chainsaw T3 has a configuration that is substantially the same as the chainsaw T1 of Embodiment 1, except that it is equipped with a battery pack B3 instead of a battery pack B1 and a battery interface 360 ​​instead of a battery interface 160. Below, only the differences between the chainsaw T3 and the chainsaw T1 will be described.

[0072] Battery pack B3 houses a rechargeable secondary battery, such as a lithium-ion battery. The output voltage of battery pack B3 is, for example, 18V. The battery capacity of battery pack B3 is, for example, 2.0Ah. The weight of battery pack B3 is, for example, approximately 375g. The width of the grip 16 of battery pack B3 in the extending direction is about the same as that of battery pack B1 (see Figure 2). Compared to battery pack B1, battery pack B3 is wider in the left-right direction. Compared to battery pack B1, battery pack B3 is wider in the direction perpendicular to the extending direction and the left-right direction of the grip 16. As a result, the volume of battery pack B3 is larger than that of battery pack B1.

[0073] The battery pack B3 is mounted to the battery interface 360 ​​by sliding it from the rear upper to the front lower. The battery interface 360 ​​also has a connection terminal 362 for connecting to the terminals (not shown) of the battery pack B3. The connection terminal 362 is electrically connected to the control unit 62 (see Figure 12) and the trigger switch 52 (see Figure 12). When the battery pack B3 is mounted to the battery interface 360, the terminals of the battery pack B3 and the connection terminal 362 are electrically connected. This allows power to be supplied from the battery pack B3 to the control unit 62 and the trigger switch 52.

[0074] As shown in Figure 12, when the battery pack B3 is attached to the battery interface 360, the outer surface of the battery pack B3 and the grip 16 are smoothly connected. The battery pack B3 can be removed by pressing in the hook 364 (see Figure 11) provided on the battery pack B3 and sliding it from the front-down to the rear-up relative to the battery interface 360.

[0075] The front end B3f and center of gravity BG3 of the battery pack B3 are located behind the rear end 50r of the trigger lever 50. The center of gravity TG3 of the chainsaw T3 is located inside the housing 4, between straight lines A2 and A3. It can also be said that the center of gravity TG3 is located near the front end of the trigger switch 52. Furthermore, the distance from straight line A2 to the center of gravity TG3 is greater than the distance from straight line A3 to the center of gravity TG3. Note that the center of gravity TG3 of the chainsaw T3 is in approximately the same position as the center of gravity TG2 of the chainsaw T2 in Embodiment 2.

[0076] (Example 4) As shown in Figure 13, the cutting tool in this embodiment is a chainsaw T4. The chainsaw T4 has a configuration that is substantially the same as the chainsaw T3 of Embodiment 3, except that it is equipped with a battery pack B4 instead of a battery pack B3. Below, only the differences between the chainsaw T4 and the chainsaw T3 will be described.

[0077] Battery pack B4 houses a rechargeable secondary battery, such as a lithium-ion battery. The voltage of battery pack B4 is, for example, 18V. The battery capacity of battery pack B4 is, for example, 6.0Ah. The weight of battery pack B4 is, for example, approximately 670g. Battery pack B4 is detachably attached to the battery interface 360, similar to battery pack B3.

[0078] Compared to battery pack B3 (see Figure 11), battery pack B4 has a larger width in the direction in which the grip 16 extends. The width of battery pack B4 in the left-right direction is about the same as that of battery pack B3. The width of battery pack B4 in the direction perpendicular to the direction in which the grip 16 extends and the left-right direction is about the same as that of battery pack B3. As a result, the volume of battery pack B4 is larger than that of battery pack B3.

[0079] As shown in Figure 14, the front end B4f and center of gravity BG4 of the battery pack B4 are located behind the rear end 50r of the trigger lever 50. Furthermore, the center of gravity TG4 of the chainsaw T4 is located inside the housing 4, and behind the straight line A3. The center of gravity TG3 can also be said to be located near the rear end of the trigger switch 52.

[0080] In the following, the Chainsaw T1, Chainsaw T2, Chainsaw T3, and Chainsaw T4 will sometimes be collectively referred to as "Chainsaw T".

[0081] (modified version) In the above embodiment, the cutting tool was described as a chainsaw T having a guide bar 6 and a saw chain 8 as the working part 10. In another embodiment, the cutting tool may be a reciprocating saw having a saw blade as the working part 10. In yet another embodiment, the cutting tool may be electric scissors having shearing blades as the working part 10. Note that if the cutting tool is a reciprocating saw or electric scissors, the cutting tool does not need to have an oil tank 66 and an oil pump 68.

[0082] In the above embodiment, a configuration was described in which the chainsaw T is a pruning chainsaw intended to be carried with one hand. In another embodiment, the chainsaw T may be a large chainsaw intended to be carried with both hands, and may have a handle for gripping with a hand other than the hand gripping the grip (corresponding to grip 16). In this case, the handle for gripping with the other hand may be provided above the housing (corresponding to housing 4) or on the side of the housing.

[0083] In the above embodiment, a configuration in which the electric motor 64 is an inner rotor type DC brushless motor was described. In another embodiment, the electric motor 64 may be an outer rotor type DC brushless motor. Alternatively, the electric motor 64 may be a brushed motor or another type of electric motor.

[0084] In the above embodiment, the chainsaw T (an example of a cutting tool) may be equipped with an engine with an internal combustion engine instead of an electric motor 64 as the prime mover for rotating the sprocket 26. In this case, the engine may be used to drive a drive shaft 84 fixed to the sprocket 26.

[0085] In the above embodiment, a configuration was described in which a plastic material such as polyamide is used for the housing 4. In another embodiment, a plastic material other than polyamide (e.g., polycarbonate) may be used for the housing 4, as long as the material has a Young's modulus greater than 100 MPa. In yet another embodiment, a material other than a plastic material (e.g., a metallic material such as aluminum) may be used for the housing 4, as long as the material has a Young's modulus greater than 100 MPa.

[0086] In the above embodiment, a configuration was described in which a rubber material such as nitrile butadiene rubber was used for the handguard 20. In another embodiment, a rubber material other than nitrile butadiene rubber (for example, ethylene propylene rubber) may be used for the handguard 20, as long as the Young's modulus is in the range of 1 MPa to 100 MPa.

[0087] In the above embodiment, at least one of the first end 202 and the second end 204 of the handguard 20 may be non-rotatably attached to at least one of the corresponding first mounting portion 22 and second mounting portion 24.

[0088] In the above embodiment, the handguard 20 may not have at least one of the multiple rib portions 210, the first rib portion 212, the second rib portion 214, and the third rib portion 216.

[0089] In the above embodiment, a configuration was described in which the handguard 20 is formed from a material with a relatively low Young's modulus (rubber material), making it more elastically deformable than the housing 4. In another embodiment, the handguard 20 may be configured to swing relative to the housing 4, like a so-called swing door. In this case, when the handguard 20 is in contact with an obstacle and a load is applied to it, the handguard 20 deforms from a closed state to an open state. In yet another embodiment, the handguard 20 may be configured to be translationally movable between a first position and a second position relative to the housing 4. In this case, when the handguard 20 is in contact with an obstacle and a load is applied to it, the handguard 20 translates between the first and second positions, changing the position of the handguard 20 relative to the housing 4. When the handguard 20 is deformed by a method other than elastic deformation, a material other than rubber (for example, a plastic material such as polyamide) may be used for the handguard 20, or a material with a Young's modulus greater than 100 MPa may be used.

[0090] In the above embodiment, the chainsaw T (an example of a cutting tool) does not necessarily have a power transmission mechanism 70. In this case, for example, the sprocket 26 may have multiple teeth formed on it, and the multiple teeth of the sprocket 26 may mesh with the first bevel gear 72a fixed to the motor shaft 80. Also, the worm wheel 68a of the oil pump 68 may mesh with the first bevel gear 72a fixed to the motor shaft 80.

[0091] In the above embodiment, a configuration was described in which a metal material such as aluminum is used for the controller case 620. In another embodiment, a metal material other than aluminum (for example, iron) may be used for the controller case 620. In yet another embodiment, a material other than a metal material (for example, a plastic material such as polyamide) may be used for the controller case 620.

[0092] As shown in Figure 15, the chainsaw T1 (an example of a cutting tool) may be equipped with an exhaust port 544 instead of the exhaust ports 144 and 146 in the above embodiment. The exhaust port 544 is provided on the head 14a of the housing body 14. In this case, when the cooling fan 82 rotates, air is discharged from the inside of the housing 4 to the outside through the exhaust port 544 instead of the exhaust ports 144 and 146. In this case as well, the cooling fan 82 can cool the electric motor 64 in conjunction with the driving of the electric motor 64. Note that the above configuration may also be applied to chainsaws T2, T3, and T4.

[0093] (Correspondence) As described above, in one or more embodiments, the chainsaw T (an example of a cutting tool) comprises a working section 10 (an example of a cutting working section), an electric motor 64 (an example of a prime mover) that drives the working section 10, a housing 4 including a housing body 14 that holds the working section 10 and houses the electric motor 64, and a grip 16 extending from the housing body 14 and held by the user's hand, and a handguard 20 attached to the housing 4 and more deformable than the housing 4, which protects the user's fingers when they are holding the grip 16.

[0094] According to the above configuration, when the handguard 20 is in contact with an obstacle and a load is applied to the handguard 20, the handguard 20 deforms relative to the housing 4. Therefore, when a user performs cutting work with the chainsaw T, even if the handguard 20 interferes with an obstacle, the chainsaw T can be positioned in the desired location and orientation. Thus, the convenience of the user can be improved in a chainsaw T equipped with a handguard 20.

[0095] In one or more embodiments, the housing 4 is formed of a material with a Young's modulus greater than 100 MPa. The handguard 20 is formed of a material with a Young's modulus ranging from 1 MPa to 100 MPa.

[0096] When the handguard 20 is deformed by elastic deformation, the larger the Young's modulus of the material used for the handguard 20, the greater the load required to deform the handguard 20 by a predetermined amount. With the above configuration, the user can sufficiently deform the handguard 20 with a relatively small load. Therefore, user convenience can be further improved.

[0097] In one or more embodiments, the housing 4 is formed of a plastic material. The handguard 20 is formed of a rubber material.

[0098] Rubber materials can undergo greater elastic deformation compared to other materials (e.g., plastic materials). With the above configuration, the user can significantly elastically deform the handguard 20. Therefore, user convenience can be further improved.

[0099] In one or more embodiments, the handguard 20 comprises a first end 202 positioned near the base end of the grip 16, a second end 204 positioned near the tip of the grip 16, and a guard body 206 extending continuously between the first end 202 and the second end 204.

[0100] According to the above configuration, the handguard 20 is positioned to cover the grip 16 from its base to its tip. This ensures reliable protection of the user's fingers when gripping the grip 16.

[0101] In one or more embodiments, the housing 4 further includes a first mounting portion 22 to which a first end 202 of the handguard 20 is attached, and a second mounting portion 24 to which a second end 204 of the handguard 20 is attached. At least one of the first end 202 and the second end 204 is rotatably mounted to at least one of the corresponding first mounting portion 22 and the second mounting portion 24.

[0102] When the handguard 20 is supported by the housing 4 at two points, a first end 202 and a second end 204, both the first end 202 and the second end 204 may be fixed to the corresponding first mounting portion 22 and second mounting portion 24. In this case, the handguard 20 can be considered a beam fixed at both ends, so the load required to deform the handguard 20 (guard body 206) by a predetermined amount becomes large. In contrast, according to the above configuration, at least one of the first end 202 and the second end 204 is rotatably attached to at least one of the corresponding first mounting portion 22 and second mounting portion 24. In this case, the handguard 20 can be considered a beam fixed at one end and simply supported (pin-supported) at the other end, or a beam simply supported (pin-supported) at both ends, so the user can sufficiently deform the handguard 20 with a relatively small load.

[0103] In one or more embodiments, the guard body 206 includes a plate portion 208 formed in a plate shape.

[0104] According to the above configuration, by making the plate portion 208 thin and spreading, the plate portion 208 can be made elastically deformable, and the plate portion 208 can protect the user's fingers over a wide area. Therefore, it is possible to realize a handguard 20 that is easily deformable while ensuring the protective function of the handguard 20.

[0105] In one or more embodiments, the guard body 206 includes a first rib portion 212 (example of a rib portion) that protrudes from the surface of the plate portion 208 at a position opposite to the grip 16 and extends in a direction toward the second end 204 from the first end 202.

[0106] If the plate portion 208 deforms excessively at the position opposite the grip 16 (the amount of deflection of the plate portion 208 becomes excessive), the distance between the grip 16 and the plate portion 208 becomes excessively narrow, and there is a risk that the plate portion 208 will be pressed against the fingers of the user gripping the grip 16. In this case, it becomes difficult for the user to change the position of their fingers, thus impairing user convenience. With the above configuration, the rigidity of the plate portion 208 at the position opposite the grip 16 is increased by the first rib portion 212. Therefore, it is possible to suppress excessive deformation of the plate portion 208 at the position opposite the grip 16 (the amount of deflection of the plate portion 208 becomes excessive). Therefore, it is possible to suppress the plate portion 208 from being pressed against the fingers of the user gripping the grip 16. Thus, user convenience can be improved.

[0107] In one or more embodiments, the first rib portion 212 protrudes from the lower surface of the plate portion 208 (for example, the surface opposite to the surface of the plate portion that faces the grip).

[0108] If the first rib portion 212 protrudes from the upper surface of the plate portion 208 (for example, the surface of the plate portion facing the grip), the first rib portion 212 may come into contact with the user's fingers when inserting and removing them between the grip 16 and the plate portion 208. In this case, it may cause inconvenience to the user and thus impair user convenience. In contrast, with the above configuration, the first rib portion 212 protrudes from the lower surface of the plate portion 208. Therefore, it is possible to prevent the first rib portion 212 from coming into contact with the user's fingers when inserting and removing them between the grip 16 and the plate portion 208. Thus, user convenience can be improved.

[0109] In one or more embodiments, the chainsaw T further includes a trigger lever 50 located near the base end of the grip 16, which acts as an electric motor 64 when pulled toward the grip 16 by the user's fingers. The guard body 206 includes a first extension 220 connected to a first end 202 and extending away from the grip 16 from the base end toward the tip end, a second extension 222 connected to a second end 204 and extending away from the grip 16 from the tip end toward the base end, and a bent portion 224 connecting the first extension 220 and the second extension 222. The length of the first extension 220 is shorter than the length of the second extension 222.

[0110] When the guard body 206 deforms, if it presses against the user's fingers while they are on the trigger lever 50, it may cause accidental operation of the trigger lever 50. In contrast, with the above configuration, the guard body 206 has increased rigidity near the bent portion 224. The bent portion 224 is shaped to protrude outward when viewed from the grip 16. As a result, when the guard body 206 is pressed against the grip 16, the bent portion 224 ensures a space between the grip 16 and the guard body 206. Also, since the bent portion 224 is located closer to the base end of the grip 16, a space is ensured near the trigger lever 50 when the guard body 206 is pressed against the grip 16. Therefore, with the above configuration, it is possible to suppress the guard body 206 from pressing against the user's fingers while they are on the trigger lever 50, and thus suppress accidental operation of the trigger lever 50. [Explanation of Symbols]

[0111] 4: Housing 6: Guide bar 6a: Notch 8: Saw chain 10: Work Department 12: Work cover 14: Housing body 14a:Head 16: Grip 18: Sprocket cover 20: Handguard 22: First mounting section 22a: Rotary shaft 24: Second mounting section 24a: Rotary shaft 26: Sprocket 28, 30: Pin 32: Bolt 36: Sprocket cover body 38: Sleeves 42:Locking member 44: Locking member body 46: Nut 48: Nail area 50: Trigger lever 50a: Rotary shaft 50f: Front end of the trigger lever 50r: Rear end of trigger lever 52: Trigger switch 54: Locking component 54a: Rotary shaft 56a: Through hole 56b: Through hole 58a: Left side lock lever 58b: Right-side lock lever 60: Torsion spring 62: Control Unit 62G: Center of gravity of the control unit 62f: Front end of the control unit 62r: Rear end of the control unit 64: Electric motor 64G: Center of gravity of the electric motor 64f: Front end of electric motor 66: Oil tank 68: Oil pump 68a: Worm wheel 70: Power transmission mechanism 70r: Rear end of power transmission mechanism 72:Reducer 72a: First bevel gear 72b: Second bevel gear 74: Coil 76: Status 78: Rotor 80: Motor shaft 82: Cooling fan 82G: Center of gravity of the cooling fan 84: Drive shaft 84a: Worm gear 140: Left side air intake 142: Right-side air intake 144: Left side exhaust port 146: Right-side exhaust port 160: Battery Interface 162: Connection terminal 164: Hook 166:Display section 202: First end 204 :Second end 206: Guard body 208: Plate section 210: Rib section 212: First rib section 214: Second rib section 216: Third rib section 220: 1st extension part 222: 2nd extension part 224: Bending section 360: Battery Interface 362: Connection terminal 364: Hook 544: Exhaust vent 620: Controller Case 660: Cap 680: Suction part 682: Oil supply route 684:Discharge part B1, B2, B3, B4: Battery pack B1f, B2f, B3f, B4f: Front end of the battery pack BG1, BG2, BG3, BG4: Center of gravity of the battery pack S: Wiring space T1, T2, T3, T4: Chainsaw TG1, TG2, TG3, TG4: Center of gravity of the chainsaw

Claims

1. A cutting operation unit; A prime mover that drives the cutting unit; a housing including a housing main body that holds the cutting unit and houses the prime mover, and a grip that extends from the housing main body and is held by a user's hand; A cutting tool comprising: a hand guard attached to the housing, protecting the user's fingers when holding the grip, and being more easily deformed than the housing.

2. the housing is made of a material having a Young's modulus greater than 100 MPa; The cutting tool of claim 1 , wherein the hand guard is formed from a material having a Young's modulus in the range of 1 MPa to 100 MPa.

3. the housing is formed from a plastic material; The cutting tool of claim 1 , wherein the hand guard is formed from a rubber material.

4. The hand guard is a first end portion disposed adjacent a base end of the grip; A second end portion disposed near a tip of the grip; 2. The cutting tool of claim 1, further comprising a guard body extending continuously between said first end and said second end.

5. The housing includes: a first attachment portion to which the first end of the hand guard is attached; a second mounting portion to which the second end of the hand guard is attached, The cutting tool of claim 4 , wherein at least one of the first end and the second end is rotatably mounted to a corresponding at least one of the first mounting portion and the second mounting portion.

6. The cutting tool according to claim 4 , wherein the guard body includes a plate portion formed in a plate shape.

7. 7. The cutting tool according to claim 6, wherein the guard body includes a rib portion that protrudes from a surface of the plate portion at a position facing the grip and extends in a direction from the first end toward the second end.

8. The cutting tool according to claim 7 , wherein the rib portion protrudes from a surface of the plate portion opposite a surface facing the grip.

9. a trigger lever provided near the base end of the grip and configured to operate the prime mover by being pulled toward the grip by a user's finger, The guard body includes: a first extension portion connected to the first end portion and extending away from the grip from the base end side toward the tip end side; a second extension portion connected to the second end portion and extending away from the grip as it moves from the tip side toward the base end side; a bending portion connecting the first extension portion and the second extension portion, The cutting tool of claim 4 , wherein the first extension has a length less than a length of the second extension.

Images