Impact tools

Abstract

To provide a technique which contributes to decrease of vibration transmission to a gripping part of an impact tool.SOLUTION: An impact tool linearly driving a tip tool along a drive shaft comprises: a tool body which regulates the drive shaft; a motor which is accommodated in the tool body; a long handle which is connected with the tool body in a cantilever condition and extends in a direction crossing the drive shaft; and at least one energizing member which is interposed between the tool body and the handle. The motor includes a motor shaft which can rotate around a shaft parallel to the drive shaft. The handle includes: a first edge part which can rotatable around a rotation shaft to be connected with the tool body; and a grip part which is arranged between the first edge part and the free edge of the handle and constituted to be gripped by an operator. At least one energizing member energizes to rotate the tool body and the handle in a direction where the grip part is away from the tool body.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an impact tool configured to linearly drive an accessory tool. [Background technology]

[0002] In an impact tool, which performs machining work on a workpiece by driving a tool tip linearly along a drive shaft, particularly large vibrations occur in the extension direction of the drive shaft. In response to this, various vibration-proof housing structures have been proposed. For example, in an impact tool (hammer drill) disclosed in Patent Document 1, the handle is elastically connected to a main body that houses a motor and a drive mechanism so as to be movable in the extension direction of the drive shaft. A first guide member provided on the outer surface of a cylindrical motor housing part of the main body and a second guide member provided on the inner surface of a cylindrical housing part of the handle arranged outside the motor housing part slide against each other to guide the relative movement between the main body and the handle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-100897 A Summary of the Invention [Problem to be solved by the invention]

[0004] The structure disclosed in Patent Document 1 can effectively suppress the transmission of vibration in the extension direction of the drive shaft from the main body to the handle. However, there is room for further improvement in reducing the transmission of vibration to the grip part that is held by the user.

[0005] An object of the present disclosure is to provide a technique that contributes to reducing the transmission of vibration to a grip portion of an impact tool. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided an impact tool configured to linearly drive a tool bit along a drive shaft. The impact tool includes a tool body, a motor, a handle, and at least one biasing member. The tool body defines a drive shaft. The motor is housed in the tool body. The motor has a motor shaft that is rotatable about an axis parallel to the drive shaft. The handle is formed in an elongated shape, is connected to the tool body in a cantilevered manner, and extends in a direction intersecting the drive shaft. The handle includes a first end and a grip portion. The first end is connected to the tool body so as to be rotatable about a rotation axis relative to the tool body. The grip portion is located between the first end and a free end of the handle, and is configured to be held by a user. The at least one biasing member is interposed between the tool body and the handle, and biases the tool body and the handle to rotate in a direction in which the grip portion and the tool body move away from each other.

[0007] According to the above configuration, the handle rotates relative to the tool body in response to vibrations generated during operation of the tool tip, and at least one biasing member absorbs the vibrations, thereby reducing vibrations transmitted from the tool body to the handle. Furthermore, by providing the pivot shaft at the first end, the amount of movement of the grip part relative to the tool body can be increased compared to when the pivot shaft is provided in the grip part, thereby enhancing the effect of reducing vibration transmission to the grip part. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a left side view of the hammer drill according to the first embodiment, showing the handle in an initial position. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a partially enlarged view of FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 4 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 2 is a partial left side view of the hammer drill with the handle in a forward position; [Figure 7]FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 11 is a left side view of the hammer drill according to the second embodiment, showing the handle in an initial position. [Figure 9] FIG. 2 is a partial left side view of the hammer drill with the left member of the handle removed, showing the handle in an initial position; [Figure 10] FIG. 2 is a partial right side view of the hammer drill with the right member of the handle removed, showing the handle in an initial position; [Figure 11] 10 is a cross-sectional view taken along line XI-XI in FIG. 8. [Figure 12] FIG. 2 is a partial left side view of the hammer drill with the left member of the handle removed, showing the handle in a forward position; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In one or more embodiments of the present disclosure, the drive shaft may be located between the pivot shaft and the grip in the extension direction of the handle. With this configuration, the handle can be more easily rotated relative to the tool body in response to vibration in the extension direction of the drive shaft of the tool body (hereinafter simply referred to as the drive shaft direction), thereby further enhancing the effect of reducing vibration transmission.

[0010] In one or more embodiments of the present disclosure, at least a portion of the grip part may be located on a line that intersects the rotation axis and extends in a direction perpendicular to the drive shaft. With this configuration, the direction of movement of the grip part accompanying the relative rotation of the handle preferably corresponds to the drive shaft direction, and transmission of vibration in the drive shaft direction to the grip part can be effectively reduced.

[0011] In one or more embodiments of the present disclosure, the position of the pivot axis may be variable, which can effectively reduce the transmission of vibrations in various directions.

[0012] In one or more embodiments of the present disclosure, the tool body and the handle may be connected to each other via at least one elastic member interposed between the tool body and the first end of the handle around the rotation axis so as to be relatively movable in a direction intersecting the rotation axis. In other words, the tool body and the first end of the handle may be elastically connected by at least one elastic member. According to this configuration, it is possible to effectively reduce the transmission of vibration in a direction intersecting the rotation axis. Furthermore, the tool body and the handle may be connected to each other via at least one elastic member so as to be relatively movable in the extension direction of the rotation axis. According to this configuration, it is possible to effectively reduce the transmission of vibration in a direction intersecting the rotation axis and in the extension direction of the rotation axis without increasing the number of parts.

[0013] In one or more embodiments of the present disclosure, the handle may be formed by a first member and a second member connected to each other in the extending direction of the rotation shaft. Also, the at least one elastic member may include a first elastic member interposed between the tool body and the first member, and a second elastic member interposed between the tool body and the second member. With this configuration, the two elastic members can be easily arranged in a well-balanced manner in the extending direction of the rotation shaft.

[0014] In one or more embodiments of the present disclosure, the at least one biasing member may be at least one spring. The at least one spring may be arranged such that the biasing direction of the at least one spring generally coincides with the extension direction of a tangent to a circle centered on the rotation axis. This configuration realizes an optimal arrangement of the spring for the relative rotation of the tool body and the handle.

[0015] In one or more embodiments of the present disclosure, the at least one biasing member may include two springs that are symmetrically arranged with respect to a plane that includes the drive shaft and extends in the extension direction of the handle. This configuration can stabilize the relative rotation between the tool body and the handle compared to when a single spring is provided.

[0016] In one or more embodiments of the present disclosure, the at least one biasing member may be at least one torsion coil spring disposed around the pivot shaft, which allows a holding structure for the at least one torsion coil spring to be relatively simple and compact.

[0017] Representative and non-limiting examples of the present disclosure will be specifically described below with reference to the drawings.

[0018] <First Example> A hammer drill 1A according to a first embodiment will be described with reference to Fig. 1 to Fig. 7. The hammer drill 1A is an example of a power tool (a so-called impact tool) capable of driving the tip tool 91 linearly by striking the tip tool 91. More specifically, the hammer drill 1A is a power tool capable of performing an operation of driving the tip tool 91 linearly along a predetermined drive axis A1 (hereinafter referred to as an impact operation) and an operation of rotating the tip tool 91 around the drive axis A1 (hereinafter referred to as a rotation operation).

[0019] As shown in FIG. 1, the outer shell of a hammer drill 1A is mainly formed by a tool body 2A and a handle 3A connected to the tool body 2A.

[0020] The tool body 2A is a hollow body that houses the main mechanism of the hammer drill 1A, and is also referred to as a main housing, an outer housing, etc. The tool body 2A extends along the drive axis A1 of the tool tip 91. A tool holder 79 is disposed in one end of the tool body 2A in the extension direction of the drive axis A1 (hereinafter simply referred to as the drive axis direction). The tool tip 91 can be removably attached to the tool holder 79. The tool body 2A mainly houses a motor 71 and a drive mechanism 75 configured to drive the tool tip 91 held by the tool holder 79 by the power of the motor 71. In this embodiment, the motor 71 is disposed so that the rotation axis A2 of the motor shaft 711 that rotates integrally with the rotor extends parallel to the drive axis A1.

[0021] The handle 3A is a long hollow body and is connected in a cantilever manner to the other end of the tool body 2A in the drive shaft direction (i.e., the end opposite to the end where the tool holder 79 is arranged). In other words, only one end of the handle 3A in the longitudinal direction is connected to the tool body 2A, and the other end of the handle 3A is a free end. More specifically, the hammer drill 1A is a pistol-type hand-held tool. The handle 3A protrudes from the other end of the tool body 2A in a direction intersecting the drive shaft A1 (more specifically, in a direction substantially perpendicular to the drive shaft A1 and the rotation shaft A2). The handle 3A includes a trigger 331 that is pressed (pulled) by a user. In the hammer drill 1A, the motor 71 is energized in response to pressing of the trigger 331, and the drive mechanism 75 is driven, thereby performing a striking operation and / or a rotating operation.

[0022] The detailed configuration of the hammer drill 1A will be described below. For convenience, in the following description, the extending direction of the drive shaft A1 (the longitudinal direction of the tool body 2A) is defined as the front-rear direction of the hammer drill 1A. In the front-rear direction, the side where the tool holder 79 is arranged is defined as the front side of the hammer drill 1A, and the opposite side (the side where the handle 3A is connected) is defined as the rear side. A direction perpendicular to the drive shaft A1 and roughly corresponding to the extending direction of the handle 3A (direction perpendicular to the drive shaft A1 and the rotation axis A2) is defined as the up-down direction of the hammer drill 1A. In the up-down direction, the side where the handle 3A is connected to the tool body 2A is defined as the upper side of the hammer drill 1A, and the protruding end side of the handle 3A is defined as the lower side of the hammer drill 1A. In addition, a direction perpendicular to the front-rear direction and the up-down direction is defined as the left-right direction of the hammer drill 1A.

[0023] First, the configuration and internal structure of the tool body 2A will be described.

[0024] As shown in FIGS. 1 to 5, the tool body 2A includes a motor accommodating portion 21, a drive mechanism accommodating portion 23, an extension portion 25, and two first spring holding portions .

[0025] The motor accommodating portion 21 is a portion that accommodates the motor 71. The motor accommodating portion 21 constitutes the rear half of the tool main body 2A. The motor accommodating portion 21 is formed in a cylindrical shape with a closed rear end.

[0026] The drive mechanism accommodating section 23 is a section that accommodates the drive mechanism 75. The drive mechanism accommodating section 23 constitutes the front half of the tool body 2A. The front end of the drive mechanism accommodating section 23 is formed in a cylindrical shape, and the tool holder 79 is disposed therein. Since this is a well-known configuration, detailed illustration and description will be omitted, but the drive mechanism 75 includes a motion conversion mechanism and an impact mechanism that perform an impact operation, and a rotation transmission mechanism that performs a rotation operation. The motion conversion mechanism typically employs a mechanism that converts rotational motion into linear motion using a swinging member (e.g., a swash bearing, a wobble plate / bearing) or a crank mechanism and a piston. The rotation transmission mechanism typically employs a reduction mechanism including a plurality of gears.

[0027] In this embodiment, the hammer drill 1A has three operation modes: an impact mode (hammering only) in which only an impact operation is performed, a rotation mode (rotation only) in which only a rotation operation is performed, and a rotation impact mode (hammering with rotation) in which an impact operation and a rotation operation are performed simultaneously. This is also a well-known configuration, so detailed illustration and description will be omitted, but the drive mechanism 75 operates according to the operation mode selected by the user via the mode switching knob.

[0028] The extension part 25 is an elongated part extending in the drive shaft direction (i.e., in the front-rear direction) above the motor housing part 21. The rear end part of the extension part 25 (i.e., the upper rear end part of the tool body 2A) is elastically connected to the handle 3A (more specifically, the second connecting part 32) via an elastic member 41. For this reason, hereinafter, the rear end part of the extension part 25 is referred to as the first connecting part 26. The connecting structure between the first connecting part 26 and the second connecting part 32 will be described in detail later.

[0029] The two first spring holding parts 28 are provided at the left and right rear ends of the motor housing part 21, respectively. Each of the first spring holding parts 28 is configured to receive (contact) the first end 431 of the two ends of the biasing spring 43. In this embodiment, a compression coil spring is used for the biasing spring 43. The biasing spring 43 is interposed in a compressed state between the first spring holding part 28 and the handle 3A (specifically, the spring receiver 371 of the second spring holding part 37), and biases the tool body 2A and the handle 3A in a direction away from each other. That is, the first spring holding part 28 is elastically connected to the handle 3A (specifically, the second spring holding part 37) via the biasing spring 43. The connection structure between the first spring holding part 28 and the second spring holding part 37 will be described in detail later.

[0030] Next, the configuration and internal structure of the handle 3A will be described.

[0031] As shown in FIG. 4, in this embodiment, the handle 3A is formed by connecting and fixing a left side member (left side shell, left side handle portion) 301 and a right side member (right side shell, right side handle portion) 302 to each other in the left-right direction at multiple points by screws.

[0032] As shown in FIGS. 1 to 5, the handle 3A includes a cover portion 31, a second connecting portion 32, a grip portion 33, and two second spring holding portions 37. As shown in FIG.

[0033] The cover portion 31 constitutes the upper part of the handle 3A. The cover portion 31 is configured to cover the rear end portion of the tool body 2A (more specifically, the rear end portion of the motor housing portion 21 and the first connecting portion 26). More specifically, the cover portion 31 includes a left wall portion, a right wall portion, a rear wall portion, and an upper wall portion that are respectively disposed on the left side, right side, rear side, and upper side of the rear end portion of the tool body 2A.

[0034] The second connecting part 32 is provided on the upper end of the cover part 31 (i.e., the upper end part 30 of the handle 3A) and is connected to the first connecting part 26 of the tool body 2A via an elastic member 41. The detailed configuration of the second connecting part 32 and the manner of connection with the first connecting part 26 will be described later.

[0035] The grip portion 33 is a portion that is gripped by a user. The grip portion 33 extends downward from the cover portion 31. That is, the grip portion 33 extends in the up-down direction below the lower end of the tool body 2A. The grip portion 33 is a long cylindrical portion. A trigger 331 is disposed at the upper end of the grip portion 33. A switch 335 is disposed behind the trigger 331 inside the grip portion 33. The switch 335 is normally held in the OFF state, and is turned ON in response to a pressing operation of the trigger 331. In response to the switch 335 being turned ON, the motor 71 is energized. In addition, a power cord 337 that can be connected to an external AC power source extends from the lower end of the grip portion 33 (the free end, the protruding end of the handle 3A).

[0036] The two second spring holding portions 37 are provided corresponding to the left and right first spring holding portions 28 of the tool body 2A, respectively. Each of the second spring holding portions 37 is configured to receive (contact) the second end portion 432 of the two ends of the biasing spring 43. The connection structure between the first spring holding portion 28 and the second spring holding portion 37 will be described in detail later.

[0037] The connecting structure between the tool body 2A and the handle 3A will be described in detail below.

[0038] First, the connection structure between the first connecting portion 26 and the second connecting portion 32 will be described in detail.

[0039] 2 and 4, the extension portion 25 of the tool body 2A includes a plate-shaped portion 250 and two disk portions 251. The plate-shaped portion 250 is formed in a long rectangular plate shape and extends linearly in the front-rear direction. The two disk portions 251 protrude to the left and right, respectively, from the rear end portion of the plate-shaped portion 250. The first connecting portion 26 is formed by the two disk portions 251 and a portion between the two disk portions 251 of the plate-shaped portion 250 (the rear end portion of the plate-shaped portion 250).

[0040] The first connecting portion 26 has a support hole 260. The support hole 260 is an opening with a circular cross section that penetrates the first connecting portion 26 in the left-right direction. The support hole 260 penetrates the center of the disk portion 251. A ring-shaped recess 261 is formed on the side surface of each disk portion 251 so as to surround the periphery of the support hole 260. A ring-shaped elastic member 41 (elastic ring) is fitted in each recess 261. In this embodiment, the elastic member 41 is formed of silicone rubber.

[0041] On the other hand, as shown in Fig. 4, the second connecting portion 32 of the handle 3A has a connecting shaft 321. As described above, in this embodiment, the handle 3A is formed of the left side member 301 and the right side member 302. The connecting shaft 321 is formed by fixing a first portion provided on the left side member 301 and a second portion provided on the right side member 302 to each other with a screw. The connecting shaft 321 extends in the left-right direction between the left wall portion and the right wall portion of the cover portion 31 within the upper end portion 30 of the handle 3A.

[0042] The diameter of the connecting shaft 321 is smaller than the diameter of the support hole 260 of the first connecting portion 26. The connecting shaft 321 is inserted through the support hole 260 and supported by two elastic members 41. One of the two elastic members 41 is interposed between the left end of the connecting shaft 321 (the first portion of the left side member 301) and the first connecting portion 26 in the radial direction of the connecting shaft 321. The other elastic member 41 is interposed between the right end of the connecting shaft 321 (the second portion of the right side member 302) and the first connecting portion 26. The two elastic members 41 hold the connecting shaft 321 and the first connecting portion 26 in a state separated from each other in the radial direction of the connecting shaft 321.

[0043] Moreover, one of the elastic members 41 is interposed between the left wall portion (left side member 301) of the cover portion 31 and the first connecting portion 26 (disk portion 251) in the axial direction (left-right direction) of the connecting shaft 321. The other of the elastic members 41 is interposed between the right wall portion (right side member 302) of the cover portion 31 and the first connecting portion 26 (disk portion 251). The two elastic members 41 hold the left side member 301, the right side member 302, and the first connecting portion 26 in a state separated from each other in the left-right direction.

[0044] With such a connection structure, the connecting shaft 321 (and thus the handle 3A) can rotate around the rotation axis A3 relative to the first connecting part 26 (and thus the tool body 2A) with the axis of the connecting shaft 321 as the rotation axis A3. In addition, the connecting shaft 321 (and thus the handle 3A) can move in a direction intersecting the rotation axis A3 and in the extension direction (left-right direction) of the rotation axis A3 relative to the first connecting part 26 (and thus the tool body 2A) in response to the elastic deformation of the elastic member 41. That is, in this embodiment, the position of the rotation axis A3 relative to the tool body 2A (and thus the drive shaft A1) can vary in response to the elastic deformation of the elastic member 41. Note that, in the description of this embodiment, it is consistently stated that "the rotation axis A3 extends in the left-right direction", but this description may also include a case where the rotation axis A3 is slightly deviated from the strict left-right direction.

[0045] Next, the connection structure between the first spring holding portion 28 and the second spring holding portion 37 will be described.

[0046] 2 and 5, the two first spring holding parts 28 of the tool body 2A are disposed symmetrically with respect to an imaginary plane P which passes through the center of the left-right direction (extension direction of the rotation axis A3) of the hammer drill 1A (tool body 2A) and extends in the up-down direction (substantial extension direction of the handle 3A). The plane P includes the drive axis A1 and can also be said to be an imaginary plane P (plane P including the drive axis A1 and the rotation axis A2) extending in the up-down direction. Each of the first spring holding parts 28 includes a spring receiver (spring seat) 281 and a spring guide 285.

[0047] The spring bearing 281 is formed in a stepped cylindrical shape including a small diameter portion and a large diameter portion, and is fixed to the outer surface of the motor housing portion 21. The spring bearing 281 is disposed below and forward of the first connecting portion 26. The central axis of the spring bearing 281 is inclined with respect to the drive shaft A1 and the rotation axis A2 of the motor shaft 711. More specifically, the central axis of the spring bearing 281 is inclined downward toward the rear. The spring bearing 281 is disposed so that the small diameter portion is located diagonally below and rearward of the large diameter portion. The first end portion 431 of the biasing spring 43, which is a compression coil spring, is fitted into the small diameter portion of the spring bearing 281 and abuts against the abutment surface 282 of the shoulder portion (the step portion at the boundary between the small diameter portion and the large diameter portion) of the spring bearing 281.

[0048] The spring guide 285 extends obliquely downward and rearward adjacent to the small diameter portion of the spring receiver 281. The spring guide 285 has a curved surface that corresponds to the outer peripheral shape of the biasing spring 43. The spring guide 285 guides the expansion and contraction of the biasing spring 43 while suppressing movement of the biasing spring 43 in a direction intersecting the axis line of the biasing spring 43.

[0049] As shown in Figs. 2 to 5, the two second spring holding parts 37 of the handle 3A are wall parts protruding forward from the left and right sides of the cover part 31, respectively. The two second spring holding parts 37 are configured to cover the left and right first spring holding parts 28 of the tool body 2A from the left and right sides, respectively. Therefore, the second spring holding parts 37 are also arranged substantially symmetrically with respect to the plane P in correspondence with the first spring holding parts 28. A rectangular opening 370 is formed in a part of each second spring holding part 37 facing the first spring holding part 28. The opening 370 is arranged so that its long side is inclined downward toward the rear in a side view. The first spring holding part 28 and the urging spring 43 are arranged inside the opening 370. The spring receiver 281 of the first spring holding part 28 is arranged within the upper front end part of the opening 370. The opening 370 is surrounded by a spring receiver (spring seat) 371 , a stopper 376 , and two restriction portions 378 .

[0050] The spring receiver 371 is a wall portion that defines the lower rear short side of the opening 370, and is disposed below and rearward of the spring receiver 281 of the first spring holding portion 28. The spring receiver 371 has an abutment surface 373 that abuts against the second end 432 of the biasing spring 43. The abutment surface 373 is substantially opposed to the abutment surface 282 of the spring receiver 281 of the first spring holding portion 28. In addition, two locking pieces 374 protrude from the spring receiver 371. The second end 432 of the biasing spring 43 is fitted between and held by the two locking pieces 374.

[0051] The stopper 376 is a wall portion that defines the upper front short side of the opening 370, and has a stopper surface 377 that can abut against the end surface 283 of the spring receiver 281 (large diameter portion). The stopper surface 377 of the stopper 376 extends substantially parallel to the abutment surface 373 of the spring receiver 371.

[0052] The two restricting portions 378 are walls that define the two long sides of the opening 370. The restricting portions 378 prevent the middle portion of the biasing spring 43 from bending excessively when the tool body 2A and the handle 3A rotate relatively to each other.

[0053] The biasing spring (compression coil spring) 43 is held in a compressed state between the spring receiver 281 (contact surface 282) of the tool body 2A (first spring holding portion 28) and the spring receiver 371 (contact surface 373) of the handle 3A (second spring holding portion 37), and biases the tool body 2A and the handle 3A to rotate. More specifically, the biasing spring 43 biases the handle 3A relative to the tool body 2A so as to rotate the grip portion 33 in a direction away from the tool body 2A (the direction of the arrow (counterclockwise direction) in FIG. 3 ; hereinafter, referred to as the first direction). The first direction can also be referred to as a direction in which the free end of the handle 3A moves backward relative to the tool body 2A, or a direction in which the angle between the tool body 2A and the grip portion 33 (the angle between the drive shaft A1 and the long axis of the handle 3A) increases.

[0054] In the initial state, the handle 3A is held in a position (position shown in Figs. 3 and 5) where the stopper surface 377 of the stopper 376 abuts against the end surface 283 of the spring receiver 281 by the biasing force of the biasing spring 43. The initial state is a state where no external force acts to rotate the handle 3A in the opposite direction relative to the tool body 2A (i.e., the direction in which the grip portion 33 approaches the tool body 2A; hereinafter, referred to as the second direction) against the biasing force of the biasing spring 43. The second direction can be said to be the direction in which the free end of the handle 3A moves forward relative to the tool body 2A, or the direction in which the angle between the tool body 2A and the grip portion 33 becomes smaller. Hereinafter, the position of the handle 3A relative to the tool body 2A in the initial state is referred to as the initial position of the handle 3A.

[0055] 3, in this embodiment, the biasing spring 43 is disposed so that, when the handle 3A is in the initial position, the axis of the biasing spring 43 (i.e., the biasing direction or expansion / contraction direction of the biasing spring 43) generally coincides with the extension direction of a tangent T of a circle centered on the rotation axis A3 of the handle 3A (i.e., the rotation direction of the handle 3A relative to the tool body 2A). When the hammer drill 1A is viewed from the left or right, the upper end of the grip portion 33 (the portion where the trigger 331 is disposed) is located on an imaginary straight line L that intersects with the rotation axis A3 and extends in the vertical direction (more specifically, an imaginary straight line that is substantially perpendicular to the drive axis A1, the rotation axis A2, and the rotation axis A3).

[0056] On the other hand, as shown in Figs. 6 and 7, the handle 3A can rotate in the second direction relative to the tool body 2A while compressing the biasing spring 43 (against the biasing force of the biasing spring 43) in response to the application of an external force. In this embodiment, a stopper 332 is provided at the upper end of the trigger 331. The stopper 332 is a protrusion that protrudes upward from the trigger 331. When the handle 3A is in the initial position (the position shown in Fig. 3), the stopper 332 is disposed at a position spaced downward from the lower end of the tool body 2A (more specifically, the motor housing part 21). The handle 3A can rotate in the second direction relative to the tool body 2A from the initial position to a position (the position shown in Fig. 6; hereinafter, referred to as the forward position) where the stopper 332 abuts against the lower end of the tool body 2A. Note that, even when the handle 3A is in the forward position, the upper end of the grip part 33 is located on the straight line L.

[0057] The actions of the tool body 2A and the handle 3A during the striking operation will now be described.

[0058] When the driving mechanism 75 performs the impact operation, the tool tip 91 is driven along the driving shaft A1, and the largest vibration is generated in the tool body 2A in the driving shaft direction (front-rear direction). In response to this vibration, the handle 3A rotates within a range between an initial position and a forward position with respect to the tool body 2A while receiving the biasing force of the biasing spring 43 in the first direction, and the grip part 33 moves relatively approximately in the front-rear direction. The biasing spring 43 also absorbs vibration by expanding and contracting in response to the relative rotation of the tool body 2A and the handle 3A. This effectively reduces the vibration transmission in the driving shaft direction from the tool body 2A to the handle 3A. In particular, the axis of the biasing spring 43 is arranged along the relative rotation direction of the tool body 2A and the handle 3A, and the arrangement of the biasing spring 43 is optimized. Furthermore, since the two biasing springs 43 are disposed symmetrically with respect to the plane P in the extending direction (left-right direction) of the rotation axis A3, the tool body 2A and the handle 3A can rotate relatively in a stable manner.

[0059] In the hammer drill 1A, the rotation axis A3 of the handle 3A is provided at the upper end 30 of the handle 3A spaced upward from the grip 33. With this configuration, the amount of movement of the grip 33 in the front-rear direction relative to the tool body 2A can be increased compared to the case where the rotation axis A3 is provided at the grip 33, and the effect of reducing vibration transmission in the front-rear direction to the grip 33 can be improved. In addition, some known impact tools have a cylindrical rear end of the tool body and a cylindrical upper end of the handle that covers the periphery of the rear end of the tool body elastically connected to each other so as to be slidable in the drive shaft direction (front-rear direction). In such impact tools, the vibration-proof effect of the grip below the cylindrical part may be slightly lower than that of the cylindrical part of the handle. With the configuration of this embodiment, the vibration-proof effect of the grip 33 can be reliably increased compared to that of the cover part 31 (upper end 30) of the handle 3A.

[0060] Furthermore, in the extension direction of the handle 3A, the drive shaft A1 is located between the rotation shaft A3 of the handle 3A and the grip portion 33. With this configuration, the handle 3A can be more easily rotated relative to the tool body 2A in response to forward and backward vibrations of the tool body 2A, compared to when the drive shaft A1 is located above the rotation shaft A3. This improves the forward and backward vibration transmission effect.

[0061] Moreover, the upper end of the grip 33 (the part corresponding to the trigger 331) is located on a straight line L that intersects with the rotation axis A3 and extends in the vertical direction. With this configuration, the movement direction of the grip 33 when the handle 3A is rotated relatively corresponds favorably to the front-rear direction. Therefore, the vibration transmission effect in the front-rear direction is improved.

[0062] Furthermore, in the hammer drill 1A, the elastic member 41 arranged around the rotation axis A3 (connecting shaft 321) allows the relative movement between the tool body 2A and the handle 3A in any direction intersecting the rotation axis A3 due to elastic deformation. Furthermore, the elastic member 41 allows the relative movement between the tool body 2A and the handle 3A in the extension direction of the rotation axis A3 (i.e., the left-right direction) due to elastic deformation. That is, in this embodiment, not only are the tool body 2A and the handle 3A allowed to rotate around the rotation axis A3, but the elastic member 41 also allows the tool body 2A and the handle 3A to move relative to each other in the front-rear direction. Therefore, the transmission of the largest vibration in the front-rear direction is further effectively reduced. In addition, the tool body 2A also generates vibrations in other directions (e.g., up-down direction, left-right direction) that are not as large as the vibrations in the front-rear direction. The connecting structure using the elastic member 41 in this embodiment can appropriately respond to vibrations in any direction other than the front-rear direction according to the elastic deformation of the elastic member 41.

[0063] In this embodiment, the two elastic members 41 are disposed between the tool body 2A and the left member 301 of the handle 3A, and between the tool body 2A and the right member 302 of the handle 3A. With this configuration, the two elastic members 41 can be easily disposed in a well-balanced manner in the left-right direction when assembling the tool body 2A and the handle 3A (the left member 301 and the right member 302). Also, the relative movement between the tool body 2A and the handle 3A can be stabilized. <Second Example> A hammer drill 1B according to the second embodiment will be described below with reference to Figures 8 to 12. The hammer drill 1B of the second embodiment includes components common to the hammer drill 1A of the first embodiment (see Figure 1). Therefore, in the following, components of the hammer drill 1B that are substantially the same as those of the hammer drill 1A (including cases where the shape is slightly different) are given the same reference numerals and descriptions thereof are omitted or simplified, and different components will be mainly described.

[0064] 8, the hammer drill 1B of the second embodiment includes a tool body 2B and a handle 3B elastically connected to the tool body 2B, similar to the hammer drill 1A of the first embodiment. However, as will be described in detail later, the connection structure between the tool body 2B and the handle 3B is different from that of the first embodiment.

[0065] The tool body 2B includes a motor housing portion 21 that houses the motor 71, a drive mechanism housing portion 23 that houses the drive mechanism 75, and a long extending portion 25 that extends in the front-rear direction above the motor housing portion 21. A rear end portion of the extending portion 25 is configured as a first connecting portion 26 (see FIG. 11).

[0066] 9 to 11, the handle 3B is formed by connecting and fixing a left member (left shell) 301 and a right member (right shell) 302 to each other in the left-right direction with screws (not shown), as in the first embodiment. The handle 3B also includes a cover part 31 that covers the rear end of the tool body 2B, a second connecting part 32 elastically connected to the first connecting part 26, and a grip part 33 having a trigger 331.

[0067] The connecting structure between the tool body 2B and the handle 3B will be described in detail below.

[0068] 11, in the present embodiment, similarly to the first embodiment, the first connecting portion 26 of the tool body 2B and the second connecting portion 32 of the handle 3B are connected via two elastic members 41. That is, the elastic members 41 are respectively interposed between the connecting shaft 321 and the first connecting portion 26 in the radial direction of the connecting shaft 321. Also, the elastic members 41 are respectively interposed between the left side member 301 and the first connecting portion 26 and between the right side member 302 and the first connecting portion 26 in the axial direction (left-right direction) of the connecting shaft 321.

[0069] With this connection structure, the connecting shaft 321 (and therefore the handle 3A) can rotate around the rotation axis A3 relative to the first connecting part 26 (and therefore the tool body 2A) with the axis of the connecting shaft 321 as the rotation axis A3. Furthermore, the tool body 2B and the handle 3B can move relative to the first connecting part 26 (and therefore the tool body 2A) in a direction intersecting the rotation axis A3 and in the extension direction of the rotation axis A3 (left and right direction) in response to elastic deformation of the elastic member 41.

[0070] 9 to 11, in this embodiment, the tool body 2B and the handle 3B are urged to rotate in a direction in which the grip portion 33 and the tool body 2B move away from each other by a urging spring 44. In this embodiment, a torsion coil spring is used as the urging spring 44, rather than a compression coil spring.

[0071] The coil portion 440 of the biasing spring 44 is disposed around the disk portion 251 on the right side of the first connecting portion 26 (the rear end portion of the extending portion 25). A locking portion 255 that protrudes upward is provided at the upper rear end portion (forward of the disk portion 251) of the extending portion 25. The first end portion 441 of the biasing spring 44 is locked in a locking groove formed in the locking portion 255. In addition, an abutment portion 315 is provided on the rear wall portion of the cover portion 31 of the handle 3B (specifically, the right member 302). The second end portion 442 of the biasing spring 44 abuts against the front surface of the abutment portion 315.

[0072] With a first end 441 engaged with the engaging portion 255 and a second end 442 abutting against the abutment portion 315, the biasing spring (torsion coil spring) 44 biases the handle 3B to rotate in a first direction (counterclockwise direction in FIG. 9) relative to the tool body 2B. In an initial state, the handle 3B is held in an initial position (position shown in FIG. 9) where stoppers (not shown) provided on the tool body 2B and the handle 3B respectively abut against each other by the biasing force of the biasing spring 44. Meanwhile, in response to the application of an external force, the handle 3B is capable of rotating in a second direction opposite to the first direction relative to the tool body 2B to a position (hereinafter referred to as a forward position) where the stopper 332 abuts against the lower end of the tool body 2A while compressing the biasing spring 44 (against the biasing force of the biasing spring 44) as shown in FIG. 12.

[0073] The action of the tool body 2B and the handle 3B during the impact operation in this embodiment is substantially the same as the action of the tool body 2A and the handle 3A in Example 1. Therefore, in this embodiment as well, as described above, the transmission of vibration from the tool body 2B to the handle 3B is effectively reduced.

[0074] Furthermore, in this embodiment, the biasing spring 44 is a torsion coil spring, and is disposed around the rotation axis A3 (disk portion 251). With this configuration, the tool body 2A and the handle 3A can be appropriately biased to rotate simply by providing the locking portion 255 and the abutment portion 315, respectively, on the tool body 2A and the handle 3A. Thus, in this embodiment, a relatively simple and compact holding structure for the biasing spring 44 is realized. Also, with the configuration of this embodiment, the biasing spring 44 can be easily assembled.

[0075] The correspondence between the configurations (features) of the above-mentioned embodiments and the configurations (features) of this disclosure is shown below. However, the configurations (features) of the embodiments are merely examples and do not limit the configurations (features) of this disclosure or the present invention.

[0076] Each of the hammer drills 1A and 1B is an example of an "impact tool". The drive shaft A1 is an example of a "drive shaft". Each of the tool bodies 2A and 2B is an example of a "tool body". The motor 71 is an example of a "motor". The motor shaft 711 is an example of a "motor shaft". The rotating shaft A2 is an example of a "axis of the motor shaft". Each of the handles 3A and 3B is an example of a "handle". The upper end portion 30 of the handles 3A and 3B is an example of a "first end". The rotating shaft A3 is an example of a "rotating shaft". The grip portion 33 is an example of a "grip". The biasing spring 43 is an example of a "biasing member" and an example of a "spring". The biasing spring 44 is another example of a "biasing member" and an example of a "spring" and a "torsion coil spring". Each of the elastic members 41 is an example of an "elastic member". The left member 301 and the right member 302 of the handles 3A and 3B are examples of the "first member" and the "second member", respectively.

[0077] It should be noted that the above embodiment is merely illustrative, and the impact tool according to the present disclosure is not limited to the illustrated hammer drills 1A and 1B. For example, non-limiting modifications as exemplified below may be made. Furthermore, at least one of these modifications may be adopted in combination with at least one of the configurations (features) of the hammer drills 1A and 1B and the claims.

[0078] In the above embodiment, the hammer drills 1A and 1B are exemplified as the impact tool, but the features of the present disclosure may be applied to another power tool capable of performing an impact operation (for example, an electric hammer capable of performing only an impact operation without performing a rotation operation). The hammer drills 1A and 1B may have only two operation modes, an impact mode and a rotation mode. The configuration and arrangement of the motor 71 and the drive mechanism 75 may be appropriately changed depending on the impact tool to which the features of the present disclosure are applied.

[0079] The connecting structure between the tool bodies 2A, 2B and the handles 3A, 3B may be changed as appropriate. For example, instead of the first connecting portion 26 and the second connecting portion 32 described above, shafts protruding to the left and right may be provided at the rear end of the tool bodies 2A, 2B, respectively, while recesses may be formed at the left wall and the right wall of the upper end 30 of the handles 3A, 3B, respectively. An annular elastic member 41 may be fitted into each recess, and the shafts of the tool bodies 2A, 2B may be supported by the elastic member 41. Instead of each of the annular elastic members 41, a plurality of elastic members may be arranged around the connecting shaft 321. Also, the rear end of the tool bodies 2A, 2B and the upper end 30 of the handles 3A, 3B may be connected via a single elastic member so as to be relatively rotatable around the rotation axis A3 and relatively movable in at least one of the front-rear direction, the up-down direction, and the left-right direction. The elastic member 41 and the elastic members of the modified examples are not limited to silicone rubber, and for example, other types of rubber, various synthetic resins that are elastically deformable, and various springs can be suitably used.

[0080] Furthermore, the rear end of the tool body 2A, 2B and the upper end 30 of the handle 3A, 3B do not necessarily need to be connected via an elastic member, and may be directly connected to each other so as to be rotatable relative to each other. For example, the connecting shaft 321 may be supported so as to be rotatable with its outer circumferential surface in contact with a surface that defines the support hole 260. In other words, the position of the rotation axis A3 may be substantially immovable.

[0081] In the above embodiment, the handles 3A, 3B are formed by two half bodies (the left member 301 and the right member 302) connected to each other in the left-right direction. However, the handles 3A, 3B may be formed by connecting half bodies divided in the front-rear direction, for example. Alternatively, the handles 3A, 3B may be formed by connecting a plurality of members divided in other directions. Similarly, the components of the tool bodies 2A, 2B and the manner of connection thereof may be appropriately changed.

[0082] In addition, the elastic member that urges the tool main body 2A, 2B and the handle 3A, 3B to rotate in a direction in which the grip portion 33 and the tool main body 2A, 2B are separated from each other is not limited to the urging springs 43, 44. For example, a leaf spring, a spiral spring, a disc spring, etc. can be adopted instead of the urging springs 43, 44. Alternatively, an elastic member other than a spring, such as rubber or synthetic resin, may be adopted. In addition, the number and positions of the urging springs 43, 44 are not limited to the number and positions exemplified in the above embodiment. For example, only one urging spring 43 in the first embodiment may be provided on the plane P. Alternatively, three or more urging springs 43 may be provided. In the second embodiment, two urging springs 44 may be provided around the left and right disc portions 251. In addition, the configuration of the spring receiving portion that receives the ends of the urging springs 43, 44 may be appropriately changed depending on the type, position, etc. of the spring adopted.

[0083] The hammer drills 1A and 1B may be configured to operate on power supplied from a rechargeable battery (also called a battery pack) instead of an external AC power source. In this case, for example, a battery mounting section to which a battery can be attached and detached is provided at the lower end (free end) of the handles 3A and 3B.

[0084] Further, in view of the spirit of the present disclosure, the following aspects are constructed, at least one of which may be adopted in combination with at least one of the features described in the above-mentioned embodiments, examples, modifications, and claims. [Aspect 1] An extension direction of the drive shaft defines a front-rear direction of the impact tool, a direction perpendicular to the axis of the drive shaft and the axis of the motor shaft defines an up-down direction of the impact tool; The first end is an upper end of the handle and is connected to a rear end of the tool body so as to be rotatable about the rotation axis. [Aspect 2] The grip portion is located lower than the tool body in the up-down direction. [Aspect 3] The rotation axis extends substantially in the left-right direction perpendicular to the front-rear direction and the up-down direction. [Aspect 4] An upper end of the grip portion has an operating member configured to be pressed by the user. The trigger 331 in the above embodiment is an example of the "operating member" of this aspect. [Aspect 5] The upper end of the gripping portion is located on a straight line that intersects the rotation axis and extends in the up-down direction. [Aspect 6] The at least one elastic member is configured to allow relative movement between the tool body and the handle at least in the extension direction of the drive shaft. [Aspect 7] The elastic member is formed in an annular shape (an elastic ring). [Aspect 8] one of the tool body and the first end of the handle includes a shaft; The at least one resilient member is disposed about the shaft and is interposed between the shaft and the other of the tool body and the first end. The connecting shaft 321 in the above embodiment is the "shaft" of this aspect. [Aspect 9] The spring is a compression coil spring extending along an axis, and is disposed so that the axis generally coincides with the extension direction of the tangent line. [Explanation of symbols]

[0085] 1A, 1B: hammer drill, 2A, 2B: tool body, 21: motor housing, 23: drive mechanism housing, 25: extension, 250: plate-shaped portion, 251: disc portion, 255: locking portion, 26: first connecting portion, 260: support hole, 261: recess, 28: first spring holding portion, 281: spring receiver, 282: abutment surface, 283: end surface, 285: spring guide, 3A, 3B: handle, 301: left side member, 302: right side member, 30: upper end portion, 31: cover portion, 315: abutment portion, 32: second connecting portion, 321: connecting shaft, 33: grip portion, 331: trigger, 332: stopper, 335: switch, 337: power cord, 37: second spring holding portion, 370: opening, 371: spring receiver, 373: abutment surface, 374: locking piece, 376: stopper, 377: stopper surface, 378: restriction portion, 41: elastic member, 43: biasing spring, 431: first end portion, 432: second end portion, 44: biasing spring, 440: coil portion, 441: first end portion, 442: second end portion, 71: motor, 711: motor shaft, 75: driving mechanism, 79: tool holder, 91: tip tool, A1: driving shaft, A2: rotating shaft, A3: turning shaft

Claims

1. An impact tool configured to linearly drive a tool bit along a drive shaft, a tool body defining the drive shaft; a motor housed in the tool body and having a motor shaft rotatable about an axis parallel to the drive shaft; a long handle connected to the tool body in a cantilever manner and extending in a direction intersecting the drive shaft, the handle including a first end connected to the tool body so as to be rotatable about a rotation axis relative to the tool body, and a grip portion located between the first end and a free end of the handle and configured to be gripped by a user; a torsion coil spring interposed between the tool body and the handle and biasing the tool body and the handle to rotate in a direction in which the grip portion and the tool body move away from each other; the torsion coil spring has a coil portion disposed around the pivot shaft, a first end portion that applies a biasing force to the tool body, and a second end portion that applies a biasing force to the handle, one of the tool body and the first end of the handle includes a shaft; the other of the tool body and the first end of the handle comprises a cylindrical portion disposed around the shaft; The tool body and the handle are connected to each other so as to be relatively movable in a direction intersecting the rotation axis and in an extension direction of the rotation axis via at least one elastic ring interposed between the shaft and the cylindrical portion around the rotation axis and in a radial direction of the shaft, The impact tool, characterized in that the coil portion is arranged around the cylindrical portion.

2. The impact tool according to claim 1, The handle is formed by a first member and a second member that are connected to each other in an extending direction of the rotation shaft, An impact tool, characterized in that the at least one elastic ring includes a first elastic ring interposed between the tool body and the first member, and a second elastic ring interposed between the tool body and the second member.

3. An impact tool configured to linearly drive a tool bit along a drive shaft, a tool body defining the drive shaft; a motor housed in the tool body and having a motor shaft rotatable about an axis parallel to the drive shaft; a long handle connected to the tool body in a cantilever manner and extending in a direction intersecting the drive shaft, the handle including a first end connected to the tool body so as to be rotatable about a rotation axis relative to the tool body, and a grip portion located between the first end and a free end of the handle and configured to be gripped by a user; at least one compression coil spring is interposed between the tool body and the handle and biases the tool body and the handle to rotate in a direction in which the grip portion and the tool body move away from each other; an axis of the at least one compression coil spring substantially coincides with an extension direction of a tangent to a circle centered on the rotation shaft and is inclined with respect to the drive shaft; The at least one compression coil spring is arranged so that a straight line perpendicular to the rotation axis and the axis line intersects with the at least one compression coil spring.

4. The impact tool according to claim 3, An impact tool, characterized in that the at least one compression coil spring includes two compression coil springs that are arranged symmetrically with respect to a plane that includes the drive shaft and extends in an extension direction of the handle.

5. The impact tool according to claim 3 or 4, An impact tool, wherein the position of the pivot shaft is variable.

6. The impact tool according to claim 5, An impact tool, characterized in that the tool body and the handle are connected to each other so as to be able to move relatively in a direction intersecting the pivot axis via at least one elastic member interposed between the tool body and the first end of the handle around the pivot axis.

7. The impact tool according to claim 6, The impact tool, wherein the tool body and the handle are connected via the at least one elastic member so as to be capable of relative movement also in the extending direction of the rotation shaft.

8. An impact tool according to any one of claims 6 to 7, The handle is formed by a first member and a second member that are connected to each other in an extending direction of the rotation shaft, An impact tool, characterized in that the at least one elastic member includes a first elastic member interposed between the tool body and the first member, and a second elastic member interposed between the tool body and the second member.

9. An impact tool according to any one of claims 1 to 8, The impact tool, wherein the drive shaft is located between the rotation shaft and the grip portion in the extending direction of the handle.

10. The impact tool according to claim 9, An impact tool, characterized in that at least a portion of the grip portion is located on a straight line that intersects the rotation axis and extends in a direction perpendicular to the drive shaft.

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