tool

Abstract

To provide a tool which has a configuration where a motor can be activated only when two kinds of accessories are attached without using a sensor.SOLUTION: A tool comprises: a motor; a switch; an operation member for the switch; a first accessory; a second accessory; a third intermediate member which is synchronized with deviation of the operation member; a first intermediate member whose position is displaced from a first block position that blocks a displacement path of the third intermediate member to a first non-block position that does not block the displacement path by attaching the first accessory; and a second intermediate member whose position is displaced from a second block position that blocks a displacement path to a second non-block position that does not block the displacement path by attaching the second accessory. When the first intermediate member is positioned at the first non-block position and when the second intermediate member is positioned at the second non-block position, displacement of the third intermediate member is allowed so that the operation member is allowed to be displaced into ON position.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tool including a prime mover. [Background technology]

[0002] A tool equipped with a prime mover may have various accessories attached in a detachable manner. For example, in a grinder having a tool tip configured to rotate, a cover (also called a wheel cover, disc cover, blade case, etc.) for covering a part of the tool tip and a side handle for a user to hold with one hand when holding the handle of the grinder with the other hand are provided as detachable accessories.

[0003] For such grinders, there is a demand for preventing the grinder from being used without the attachment. For example, the following Patent Document 1 discloses a grinder equipped with a sensor that detects whether or not a cover is attached, and a controller that prohibits the rotation of the tool tip when the cover is not attached. Also, the following Patent Document 2 discloses a grinder equipped with a sensor that detects whether or not a cover is attached, and a sensor that detects whether or not a side handle is attached. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 051893 [Patent Document 2] US Patent Application Publication No. 2018 / 272494 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the techniques described in Patent Documents 1 and 2, if the sensor breaks down or if the sensitivity of the sensor is reduced due to the adhesion of dust, there is a risk that the attachment of the cover or the side handle cannot be detected. In addition, in a configuration in which the rotation of the tip tool is prohibited unless both the cover and the side handle are attached, it is necessary to provide individual sensors for the cover and the side handle, which leads to an increase in costs. This problem is not limited to grinders, but is common to any tool that has a prime mover and can detachably attach two types of accessories. For this reason, it is desirable to realize a configuration in a tool that can drive the prime mover only when two types of accessories are attached, without using a sensor. [Means for solving the problem]

[0006] This specification discloses a tool, which may include a prime mover, a switch for driving the prime mover, an operating member configured to be displaceable between an OFF position that turns the switch to an OFF state and an ON position that turns the switch to an ON state, a first accessory, a second accessory, a first mounting portion configured to detachably mount the first accessory, a second mounting portion configured to detachably mount the second accessory, a first intermediate member configured to be displaced by mounting the first accessory to the first mounting portion, a second intermediate member configured to be displaced by mounting the second accessory to the second mounting portion, and a third intermediate member configured to be displaced on a displacement path between an OFF corresponding position corresponding to the OFF position and an ON corresponding position corresponding to the ON position in conjunction with the displacement of the operating member. The first intermediate member may be located at a first blocking position blocking the displacement path of the third intermediate member when the first accessory is not attached to the first attachment portion, and may be located at a first non-blocking position not blocking the displacement path of the third intermediate member when the first accessory is attached to the first attachment portion. The second intermediate member may be located at a second blocking position blocking the displacement path of the third intermediate member when the second accessory is not attached to the second attachment portion, and may be located at a second non-blocking position not blocking the displacement path of the third intermediate member when the second accessory is attached to the second attachment portion. When the first intermediate member is located at the first non-blocking position and the second intermediate member is located at the second non-blocking position, the third intermediate member may be permitted to displace from the OFF corresponding position to the ON corresponding position, thereby permitting the displacement of the operating member from the OFF position to the ON position. When at least the first intermediate member is positioned in the first blocking position, or when at least the second intermediate member is positioned in the second blocking position, displacement of the third intermediate member from the off corresponding position to the on corresponding position may be prevented by at least one of the first intermediate member and the second intermediate member, thereby preventing displacement of the operating member from the off position to the on position.

[0007] According to this tool, when at least one of the first accessory and the second accessory is not attached, at least one of the first intermediate member and the second intermediate member blocks the displacement path of the third intermediate member, thereby preventing the operation member from displacing from the OFF position to the ON position. When the first accessory is attached to the first attachment section and the second accessory is attached to the second attachment section, the first intermediate member and the second intermediate member displace to positions that do not block the displacement path of the third intermediate member, thereby allowing the operation member to displace from the OFF position to the ON position. Thus, a configuration that can drive the prime mover only when both the first accessory and the second accessory are attached can be realized using only a mechanical structure without using a sensor. [Brief description of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional view of a grinder according to a first embodiment of the present invention, showing a state in which a side grip and a wheel cover are attached and an operating member is in an ON position. [Diagram 2] FIG. 2 is a longitudinal cross-sectional view of the grinder with the side grip and wheel cover removed and the operating member in the off position. [Diagram 3] FIG. 2 is a partially enlarged view of the grinder shown in FIG. [Figure 4] FIG. 3 is a partially enlarged view of the grinder shown in FIG. 2. [Diagram 5] FIG. 2 is a partially enlarged view of the grinder shown in FIG. [Figure 6] FIG. 3 is a partially enlarged view of the grinder shown in FIG. 2. [Figure 7] FIG. 4 is a perspective view of a first intermediate member. [Figure 8] FIG. 4 is a perspective view of a second intermediate member. [Figure 9] 4 is a perspective view of a holding member that holds a first intermediate member and a second intermediate member. FIG. [Figure 10] FIG. 11 is a perspective view of a third intermediate member. [Figure 11] FIG. 2 is a perspective view showing components of the conversion mechanism. [Figure 12] FIG. 2 is a perspective view showing components of the conversion mechanism. [Figure 13] FIG. 2 is a perspective view showing components of the conversion mechanism. [Figure 14] FIG. 2 is a diagram showing the internal structure of the grinder with the side grips and wheel covers removed. [Figure 15] FIG. 2 is a diagram showing the internal structure of the grinder with the side grips attached and the wheel covers removed. [Figure 16] FIG. 2 is a diagram showing the internal structure of the grinder with the side grip and wheel cover attached. [Figure 17] FIG. 11 is a longitudinal sectional view of a grinder according to a second embodiment of the present invention, showing a state in which the side grip is not attached and the operating member is in a lock-off position. [Figure 18] 11 is a longitudinal sectional view of a grinder according to a second embodiment, showing a state in which a side grip is attached and an operating member is in an unlocked position and an off position. FIG. [Figure 19] 11 is a longitudinal sectional view of a grinder according to a second embodiment, showing a state in which a side grip is attached and an operating member is in an unlocked position and an on position. FIG. [Figure 20] FIG. 18 is a partial enlarged view of the grinder shown in FIG. [Figure 21] FIG. 19 is a partial enlarged view of the grinder shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In one or more embodiments, the tool may include a prime mover, a switch for driving the prime mover, an operating member configured to be displaceable between an off position that sets the switch to an off state and an on position that sets the switch to an on state, a first accessory, a second accessory, a first mounting portion configured to removably attach the first accessory, a second mounting portion configured to removably attach the second accessory, a first intermediate member configured to be displaced by attaching the first accessory to the first mounting portion, a second intermediate member configured to be displaced by attaching the second accessory to the second mounting portion, and a third intermediate member configured to be displaced on a displacement path between an off corresponding position corresponding to the off position and an on corresponding position corresponding to the on position in response to displacement of the operating member. The first intermediate member may be located at a first blocking position blocking the displacement path of the third intermediate member when the first accessory is not attached to the first attachment portion, and may be located at a first non-blocking position not blocking the displacement path of the third intermediate member when the first accessory is attached to the first attachment portion. The second intermediate member may be located at a second blocking position blocking the displacement path of the third intermediate member when the second accessory is not attached to the second attachment portion, and may be located at a second non-blocking position not blocking the displacement path of the third intermediate member when the second accessory is attached to the second attachment portion. When the first intermediate member is located at the first non-blocking position and the second intermediate member is located at the second non-blocking position, the third intermediate member may be permitted to displace from the OFF corresponding position to the ON corresponding position, thereby permitting the displacement of the operating member from the OFF position to the ON position. When at least the first intermediate member is positioned in the first blocking position, or when at least the second intermediate member is positioned in the second blocking position, displacement of the third intermediate member from the off corresponding position to the on corresponding position may be prevented by at least one of the first intermediate member and the second intermediate member, thereby preventing displacement of the operating member from the off position to the on position.

[0010] According to this tool, when at least one of the first accessory and the second accessory is not attached, at least one of the first intermediate member and the second intermediate member blocks the displacement path of the third intermediate member, thereby preventing the operation member from displacing from the OFF position to the ON position. When the first accessory is attached to the first attachment section and the second accessory is attached to the second attachment section, the first intermediate member and the second intermediate member displace to positions that do not block the displacement path of the third intermediate member, thereby allowing the operation member to displace from the OFF position to the ON position. Thus, a configuration that can drive the prime mover only when both the first accessory and the second accessory are attached can be realized using only a mechanical structure without using a sensor.

[0011] In one or more embodiments, the prime mover may be an electric motor. The tool may be a grinder including an end tool configured to be rotated by the electric motor. The first accessory may be a side grip. The second accessory may be a cover that partially covers the end tool. This configuration allows for a grinder that can drive the electric motor only when both the side grip and the cover are attached, without the use of a sensor.

[0012] In one or more embodiments, the first attachment portion may include at least two side grip attachment portions for selectively attaching the side grips. The first intermediate member may be a single member provided in common to the at least two side grip attachment portions. The first intermediate member may have at least one pressed portion that is pressed directly or indirectly by the side grip when the side grip is attached to one side grip attachment portion arbitrarily selected from the at least two side grip attachment portions, and may be configured to be displaced when the at least one pressed portion is pressed. According to this configuration, a single first intermediate member is shared by the at least two side grip attachment portions, thereby reducing the number of parts.

[0013] In one or more embodiments, the first intermediate member may include a first intermediate member body having a ring or partial ring shape. The at least two side grip attachment portions may be located at positions spaced apart from one another in a circumferential direction of the ring or partial ring. With this configuration, the first intermediate member has a shape corresponding to the arrangement of the at least two side grip attachment portions, so that a single first intermediate member can be shared by the at least two side grip attachment portions with a simple configuration.

[0014] In one or more embodiments, the first intermediate member may be configured to rotate about the axis of rotation when at least one pressed portion is pressed. With this configuration, when at least two side grip attachment portions are located at positions spaced apart from each other in the circumferential direction of the ring or partial ring, the first intermediate member can be easily displaced even when the first accessory is attached to any of the at least two side grip attachment portions. In addition, since there is no need to secure a space for displacing the first intermediate member in the direction in which the axis of rotation extends, the size of the tool in the direction in which the axis of rotation extends can be made compact.

[0015] In one or more embodiments, the at least one pressed portion may protrude radially outward from the first intermediate member body. The at least one pressed portion may be provided at at least two positions corresponding to the positions of the at least two side grip attachment portions, respectively. This configuration allows the first intermediate member to be easily rotated.

[0016] In one or more embodiments, the first intermediate member may include a blocking portion that blocks the displacement path of the third intermediate member when the first intermediate member is in the first blocking position. The blocking portion may protrude radially outward from the first intermediate member body. With this configuration, the third intermediate member can be disposed around the outer edge of the tool while avoiding the locations where the main components of the tool are disposed.

[0017] In one or more embodiments, the first intermediate member body may have a first through hole having an arc shape centered on the rotation axis. The first intermediate member may be screwed through the first through hole so as to be rotatable along the arc shape. With this configuration, the first intermediate member can be rotatably held with a simple configuration.

[0018] In one or more embodiments, at least one of the pressed portions may have a pressed surface that is angled with respect to the longitudinal direction of the side grip such that the first intermediate member is displaced in a direction different from the longitudinal direction of the side grip when the side grip is attached to one of the side grip attachment portions. This configuration allows the first intermediate member to be easily rotated.

[0019] In one or more embodiments, the second intermediate member may be configured to be directly or indirectly pressed against the cover when the cover is attached to the second attachment portion, and to move linearly. According to this configuration, if the attachment direction of the cover is set to the linear movement direction of the second intermediate member, no direction conversion mechanism is required, and the second intermediate member can be displaced with a simple configuration.

[0020] In one or more embodiments, the second intermediate member may have a second through hole in the form of a long hole whose longitudinal direction is the direction in which the second intermediate member moves linearly. The second intermediate member may be screwed through the second through hole so as to be linearly movable along the long hole. With this configuration, the second intermediate member can be held linearly movable with a simple configuration.

[0021] In one or more embodiments, the rotational axis of the electric motor and the rotational axis of the tool accessory may intersect.

[0022] In one or more embodiments, the first and second mounting portions may be disposed on a first side in a longitudinal direction of the tool. The operating member may be disposed on a second side opposite to the first side. The third intermediate member may be an elongated member extending in the longitudinal direction. With this configuration, the above-described aspects of the present invention can be easily realized even when the first and second mounting portions and the operating member are disposed at positions relatively far from each other.

[0023] In one or more embodiments, the tool may include a single holding member that holds the first intermediate member and the second intermediate member. With this configuration, when the first intermediate member and the second intermediate member are attached to the holding member, the relative positions of the first intermediate member and the second intermediate member are automatically determined. In other words, there is no need to adjust the relative positions of the first intermediate member and the second intermediate member when assembling the tool.

[0024] In one or more embodiments, the first displacement direction, which is the displacement direction of the operating member, and the second displacement direction, which is the displacement direction of the third intermediate member, may be different from each other. The tool may include a conversion mechanism configured to convert the movement of the operating member in the first displacement direction into the movement of the third intermediate member in the second displacement direction. With this configuration, the displacement direction of the operating member is not subject to design constraints, so that an optimal type of operating member can be adopted depending on the specifications of the tool.

[0025] In one or more embodiments, the tool may be a grinder. The grinder may include a handle housing for a user to hold and a motor housing for accommodating an electric motor. The handle housing may be located on the opposite side of the motor housing to the tool bit in a direction in which the rotation axis of the electric motor extends. Such a grinder is easy to apply the above-mentioned aspects.

[0026] In one or more embodiments, the tool may include a switch for driving a prime mover, an operating member configured to be displaceable in a first direction between an OFF position that turns the switch to an OFF state and an ON position that turns the switch to an ON state, a mounting section configured to detachably mount an accessory, a lock-off section configured to switch a status of the operating member between a locked-off state in which displacement of the operating member from the OFF position to the ON position is prevented and a unlocked state in which displacement of the operating member from the OFF position to the ON position is permitted by changing an engagement state with the operating member, and a first intermediate member configured to be displaced by being pressed directly or indirectly by the accessory when the accessory is mounted on the mounting section. The first intermediate member may be located in a blocking position that blocks a release operation for switching the locked-off state to the unlocked state by inter-member abutment when the accessory is not mounted on the mounting section, and in a permitting position that permits the release operation due to the absence of inter-member abutment when the accessory is mounted on the mounting section.

[0027] According to this tool, the configuration that allows the prime mover to be driven only when an accessory is attached can be realized by using only a mechanical structure without using a sensor. Also, since the operation of releasing the lock-off usually involves a displacement of a component that is easily identifiable by a user, if the prime mover cannot be driven despite the operation of displacing the operating member from the OFF position to the ON position, it is easy for the user to realize that the reason is not a switch failure but that an accessory is not attached.

[0028] In one or more embodiments, the lock-off portion may be a fixed engagement structure. The operating member may be configured to be displaceable in a second direction different from the first direction from a lock-off position corresponding to the locked-off state to a lock-off release position corresponding to the locked-off release state. The release operation may be displacing the operating member from the locked-off position to the lock-off release position.

[0029] In one or more embodiments, the tool may further include a second intermediate member configured to move in conjunction with a displacement of the operating member in the second direction between a first corresponding position corresponding to the unlocked position of the operating member and a second corresponding position corresponding to the unlocked position of the operating member. The first intermediate member may be configured to be displaced such that, when in the blocking position, the first intermediate member blocks a displacement path of the second intermediate member from the first corresponding position to the second corresponding position, and when in the allowing position, the first intermediate member does not block a displacement path of the second intermediate member from the first corresponding position to the second corresponding position. With this configuration, the first intermediate member and the operating member may be disposed apart from each other, improving the design freedom of the tool.

[0030] Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings. In the following embodiment, a handheld electric disc grinder (hereinafter simply referred to as grinder) 10 will be exemplified as a tool equipped with a prime mover.

[0031] As shown in Figs. 1 and 2, the grinder 10 is configured to rotate a substantially disk-shaped tool tip 28 attached to a spindle 25. The spindle 25 is rotated by a rotational driving force provided by an electric motor 31 as a prime mover. As the tool tip 28 that can be attached to the grinder 10, a grindstone, a rubber pad, a brush, a blade, etc. are prepared. A user selects an appropriate tool tip 28 according to a desired processing operation and attaches it to the grinder 10. The grinder 10 can perform processing operations such as grinding, polishing, and cutting on a workpiece according to the type of tool tip 28.

[0032] In the following description, the direction in which the rotation axis AX1 of the electric motor 31 (in other words, the motor shaft 32) extends is defined as the front-rear direction of the grinder 10. In the front-rear direction, the side where the tool tip 28 is located is defined as the front side, and the opposite side is defined as the rear side. In addition, the direction in which the rotation axis AX2 of the spindle 25 (in other words, the rotation axis of the tool tip 28) extends is defined as the up-down direction of the grinder 10. In the up-down direction, the side where the tool tip 28 is located is defined as the lower side, and the opposite side is defined as the upper side. In addition, the direction perpendicular to the up-down direction and the front-rear direction is defined as the left-right direction of the grinder 10. In the left-right direction, the right side when viewed from the rear side to the front side is defined as the right side of the grinder 10, and the opposite side is defined as the left side of the grinder 10.

[0033] 1 and 2, the grinder 10 includes a gear housing 20, a motor housing 30, and a handle housing 40. An electric motor 31 is accommodated in the motor housing 30, which is located between the gear housing 20 and the handle housing 40 in the front-rear direction, i.e., in the longitudinal direction of the grinder 10. The electric motor 31 is configured to be driven by power supplied from the outside (AC power in this embodiment, but may be DC power).

[0034] A mechanism for transmitting the rotational driving force of the electric motor 31 to the tool tip 28 is accommodated in the gear housing 20. Specifically, the small bevel gear 23, the large bevel gear 24, and the spindle 25 are accommodated in the gear housing 20. The small bevel gear 23 is fixed around the motor shaft 32 at the front end of the motor shaft 32 of the electric motor 31. The spindle 25 is supported rotatably about the rotation axis AX2 by bearings arranged at a distance in the vertical direction. The rotation axis AX2 intersects (more specifically, is perpendicular to) the rotation axis AX1 of the electric motor 31. The large bevel gear 24 is fixed around the spindle 25 above the spindle 25 and meshes with the small bevel gear 23. The gear housing 20 has a second mounting portion 22 at its lower end for detachably mounting the cover 300. The second mounting portion 22 has a cylindrical shape extending in the vertical direction. The spindle 25 extends in the vertical direction within the gear housing 20, and extends from the gear housing 20 (more specifically, from the second mounting portion 22) on the lower side.

[0035] An inner flange 26 is attached around the spindle 25 at the lower end of the spindle 25 extending from the gear housing 20. A male thread is formed below the inner flange 26 on the spindle 25, and a lock nut 27 is attached to the male thread. A tool tip 28 is sandwiched between the inner flange 26 and the lock nut 27, and the position of the tool tip 28 relative to the spindle 25 is fixed by tightening the lock nut 27.

[0036] The handle housing 40 is a portion that a user holds with one hand when using the grinder 10. The handle housing 40 has a cylindrical shape that extends generally in the front-rear direction. A switch 41 for driving the electric motor 31 is accommodated inside the handle housing 40. An operating member 50 is provided below the handle housing 40 and configured to be displaceable between an OFF position (see FIG. 2) that turns the switch 41 to an OFF state and an ON position (see FIG. 1) that turns the switch 41 to an ON state.

[0037] When the user operates the operating member 50 from the OFF position to the ON position to drive the electric motor 31, the rotation of the motor shaft 32 is transmitted to the spindle 25 while being decelerated via the small bevel gear 23 and the large bevel gear 24. At this time, the direction of the rotational motion is also converted from the direction around the motor shaft 32 to the direction around the rotation axis AX2 of the spindle 25. According to this mechanism, the spindle 25 rotates around the rotation axis AX2 in conjunction with the rotation of the motor shaft 32, and as a result, the tip tool 28 fixed by the inner flange 26 and the lock nut 27 rotates together with the spindle 25.

[0038] As shown in FIG. 1, the grinder 10 further includes a side handle 200 and a cover 300 as accessories. The side handle 200 is provided for a user to hold with the hand opposite to the hand holding the handle housing 40. By using the side handle 200, the user can hold the grinder 10 more stably. The side handle 200 includes a grip portion 210 for the user to hold, and an attachment portion 220 for attachment to the gear housing 20. The attachment portion 220 has a cylindrical shape extending in the longitudinal direction of the side handle 200, and extends from one end of the grip portion 210 in the longitudinal direction of the side handle 200. A male screw is formed on the outer circumferential surface of the attachment portion 220.

[0039] As shown in FIG. 14, the gear housing 20 has three first mounting parts 29a to 29c for detachably mounting the side handle 200. The first mounting parts 29a to 29c are arranged at positions spaced apart from each other in the circumferential direction around the rotation axis AX1. More specifically, the first mounting part 29a is formed on the left side surface of the gear housing 20, the first mounting part 29b is formed on the upper surface of the gear housing 20, and the first mounting part 29c is formed on the right side surface of the gear housing 20. The three first mounting parts 29a to 29c are provided at positions rotationally symmetrical with respect to the rotation axis AX1. Each of the first mounting parts 29a to 29c is in the form of a through hole that communicates the inside and outside of the gear housing 20. A female screw that screws into the male screw of the mounting part 220 is formed on the inner surface that forms the through hole.

[0040] The side handle 200 can be attached to the gear housing 20 by screwing the attachment portion 220 of the side handle 200 into one selected from the three first attachment portions 29a to 29c. The user can arbitrarily select the attachment location of the side handle 200 from the first attachment portions 29a to 29c depending on the type of work to be performed using the grinder 10 or whether the user is right-handed or left-handed. In this embodiment, three first attachment portions 29a to 29c are provided, but the number of first attachment portions is not particularly limited and may be any number equal to or greater than one. For example, only two first attachment portions 29a, 29c may be provided.

[0041] As shown in FIG. 1, the cover 300 includes a cover body 310 that covers a part of the tool bit 28, and a mounting portion 320 for mounting to the second mounting portion 22. The cover body 310 covers approximately the rear half of the tool bit 28. In this embodiment, the cover body 310 covers the upper surface, the lower surface, and the circumferential surface between the upper surface and the lower surface of the tool bit 28, but depending on the type of tool bit 28 used, the cover body 310 may cover only the upper surface and the circumferential surface. The mounting portion 320 has an open, approximately annular shape and extends upward from the upper surface of the cover body 310. The structure of the mounting portion 320 is well known, so it is not shown in the drawings, but the mounting portion 320 has two opposing flanges at two circumferential ends. With the mounting portion 320 positioned so as to surround the second mounting portion 22 of the gear housing 20, a bolt is inserted into a screw hole formed in the flange and tightened, thereby reducing the radius of the annular shape of the mounting portion 320 and fixing the mounting portion 320 to the second mounting portion 22.

[0042] The above-mentioned grinder 10 has a mechanical configuration in which the operating member 50 can be displaced from the OFF position to the ON position only when the side handle 200 is attached to any one of the first attachment parts 29a to 29c of the gear housing 20 and the cover 300 is attached to the second attachment part 22 of the gear housing 20, and the operating member 50 is prevented from being displaced from the OFF position to the ON position when at least one of the side handle 200 and the cover 300 is not attached. The mechanical configuration will be described in detail below with reference to the drawings.

[0043] 4, an operating member 50 is provided on the underside of the handle housing 40. In this embodiment, the operating member 50 is a paddle type, but may be implemented in any other type. The operating member 50 extends over almost the entire range of the handle housing 40 in the front-rear direction.

[0044] The operating member 50 includes a support shaft 51, a projection 52, a spring seat 53, a spring 54, and an action end 55. The support shaft 51 is provided near the rear end of the operating member 50. The support shaft 51 has a cylindrical shape extending in the left-right direction, and is rotatably supported by the handle housing 40. The projection 52 extends in an L-shape toward the upper and front sides at approximately the center of the operating member 50 in the front-rear direction. The tip of the projection 52 engages with the input member 42 of the switch 41. One end of the spring 54 is seated on the spring seat 53. The other end of the spring 54 is seated on the handle housing 40. The spring 54 biases the operating member 50 toward the off position. The action end 55 is the front end of the operating member 50 in the front-rear direction. A second horizontally extending portion 123 of a second link member 120 (described later) is placed on the action end 55.

[0045] When the user grasps the handle housing 40 and the operating member 50 (in other words, presses the operating member 50 upward) in a state where the operating member 50 is in the OFF position (see FIG. 4), the operating member 50 rotates about the support shaft 51 as a fulcrum in a direction approaching the handle housing 40 to the ON position (see FIG. 3) against the biasing force of the spring 54. When the operating member 50 is displaced from the OFF position to the ON position, the protrusion 52 of the operating member 50 is also displaced upward, and as a result, the input member 42 engaged with the protrusion 52 is also displaced upward. When the operating member 50 reaches the ON position, the input member 42 is pushed into the switch 41. The switch 41 detects that the input member 42 has been pushed in, and sends a signal to a controller (not shown) to drive the electric motor 31. When the controller receives this signal, it supplies power to the electric motor 31.

[0046] When the user releases his / her finger from the operating member 50, the operating member 50 returns from the ON position to the OFF position due to the biasing force of the spring 54. This causes the protrusion 52 and therefore the input member 42 to return to their original positions. The switch 41 detects that the input member 42 has been withdrawn and sends a signal to the controller to stop the electric motor 31. Upon receiving this signal, the controller stops the supply of power to the electric motor 31. A lock-off switch 57 is provided near the front end of the operating member 50 in the front-rear direction to lock the operating member 50 in the OFF position and prevent it from being displaced to the ON position.

[0047] 1 and 2, the grinder 10 further includes a first intermediate member 60, a second intermediate member 70, a holding member 140, a third intermediate member 80, and a conversion mechanism 100. First, an overview of the first intermediate member 60, the second intermediate member 70, the holding member 140, the third intermediate member 80, and the conversion mechanism 100 will be described.

[0048] The first intermediate member 60 is configured to be pressed against the mounting portion 220 of the side handle 200 and displaced by attaching the side handle 200 to any of the first mounting portions 29a to 29c. In this embodiment, the first intermediate member 60 rotates a predetermined angle about the rotation axis AX1 as a displacement operation. The first intermediate member 60 is a substantially annular member, and is disposed inside the gear housing 20 forward of the electric motor 31 so as to surround the motor shaft 32.

[0049] The second intermediate member 70 is configured to be pressed against the mounting portion 320 of the cover 300 by mounting the cover 300 to the second mounting portion 22, and displaced. In this embodiment, the second intermediate member 70 moves linearly upward as such a displacing motion. The second intermediate member 70 is disposed between the motor shaft 32 and the tool bit 28, forward of the first intermediate member 60. The holding member 140 is disposed forward of the first intermediate member 60, and holds the first intermediate member 60 and the second intermediate member 70 together.

[0050] The third intermediate member 80 is disposed to extend in the front-rear direction at the bottom of the gear housing 20 and the motor housing 30. The third intermediate member 80 is configured to be displaced in the front-rear direction between an OFF corresponding position (see FIG. 6) corresponding to the OFF position of the operating member 50 and an ON corresponding position (see FIG. 5) corresponding to the ON position of the operating member 50 in conjunction with the displacement of the operating member 50. The conversion mechanism 100 is configured to convert the rotational movement of the operating member 50 in a substantially vertical direction into a linear movement of the third intermediate member 80 in the front-rear direction.

[0051] When the side handle 200 is not attached to any of the first mounting portions 29a to 29c of the gear housing 20, the first intermediate member 60 is located in a first blocking position (see Figures 6 and 14) that blocks the displacement path for the third intermediate member 80 to displace from the off corresponding position to the on corresponding position, and when the side handle 200 is attached to any of the first mounting portions 29a to 29c, the first intermediate member 60 is located in a first non-blocking position (see Figures 5, 15 and 16) that does not block the displacement path of the third intermediate member 80.

[0052] When the cover 300 is not attached to the second mounting portion 22 of the gear housing 20, the second intermediate member 70 is located in a second blocking position (see Figures 6, 14, and 15) that blocks the displacement path of the third intermediate member 80, and when the cover 300 is attached to the second mounting portion 22, the second intermediate member 70 is located in a second non-blocking position (see Figures 5 and 16) that does not block the displacement path of the third intermediate member 80.

[0053] Hereinafter, the first intermediate member 60, the second intermediate member 70, the holding member 140, the third intermediate member 80, and the conversion mechanism 100 will be described in detail. First, the first intermediate member 60 will be described. As shown in FIG. 7, the first intermediate member 60 is a single member, and is provided in common with the first mounting portions 29a to 29c. The first intermediate member 60 includes a first intermediate member body 61. In this embodiment, the first intermediate member body 61 has a ring shape centered on the rotation axis AX1 of the electric motor 31. However, the first intermediate member 60 may have a partial ring shape (in other words, a ring shape that is not closed). A through hole through which the motor shaft 32 passes is formed in the center of the first intermediate member body 61.

[0054] The first intermediate member 60 further includes three pressed portions 62a to 62c and a blocking portion 64. The three pressed portions 62a to 62c are arranged spaced apart from one another in the circumferential direction. The pressed portion 62a is a portion that is pressed by the side handle 200 (more specifically, the tip of the mounting portion 220) when the side handle 200 is attached to the first mounting portion 29a of the gear housing 20. Similarly, the pressed portion 62b is a portion that is pressed by the side handle 200 when the side handle 200 is attached to the first mounting portion 29b, and the pressed portion 62c is a portion that is pressed by the side handle 200 when the side handle 200 is attached to the first mounting portion 29c. Therefore, the pressed portions 62a to 62c are arranged at angular positions corresponding to the angular positions of the first mounting portions 29a to 29c, respectively (see FIG. 14). Each of the pressed portions 62a to 62c protrudes from the first intermediate member body 61 radially outward.

[0055] As described above, the first intermediate member 60 is configured to rotate about the rotation axis AX1 when any of the pressed portions 62a to 62c is pressed by the side handle 200. Comparing Figures 14 and 15, it can be seen that by attaching the side handle 200 to the first mounting portion 29c, the pressed portion 62c is pressed by the side handle 200, and the first intermediate member 60 rotates counterclockwise from the position shown in Figure 14 to the position shown in Figure 15.

[0056] As shown in FIG. 7 and FIG. 14, the pressed portion 62a has a pressed surface 63a angled with respect to the longitudinal direction of the side handle 200 when the side handle 200 is attached to the first attachment portion 29a (in other words, the attachment direction of the side handle 200). Similarly, the pressed portion 62b has a pressed surface 63b angled with respect to the longitudinal direction of the side handle 200 when the side handle 200 is attached to the first attachment portion 29b. Similarly, the pressed portion 62c has a pressed surface 63c angled with respect to the longitudinal direction of the side handle 200 when the side handle 200 is attached to the first attachment portion 29c. The pressed surfaces 63a to 63c are angled at about 45 degrees with respect to the longitudinal direction of the corresponding side handle 200 (see FIG. 14). This angle can be set at any angle so that the first intermediate member 60 is displaced in a direction different from the longitudinal direction of the side handle 200. In an alternative embodiment, the angle may be set within a range of not less than 30 degrees and not more than 60 degrees. With the pressed surfaces 63a to 63c angled in this manner, the first intermediate member 60 can be easily rotated.

[0057] The blocking portion 64 is a portion that blocks the displacement path of the third intermediate member 80 when the side handle 200 is not attached to any of the first attachment portions 29a to 29c. The blocking portion 64 protrudes radially outward from the first intermediate member body 61. When the side handle 200 is not attached to any of the first attachment portions 29a to 29c, the blocking portion 64 is located at the bottommost portion of the first intermediate member 60 (see FIG. 14). On the other hand, when the side handle 200 is attached to any of the first attachment portions 29a to 29c, the blocking portion 64 retreats to the upper right side of the bottommost portion due to the rotation of the first intermediate member 60 (see FIG. 15).

[0058] As shown in FIG. 7, the first intermediate member body 61 includes first through holes 65, 66. Each of the first through holes 65, 66 has an arc shape centered on the rotation axis AX1. The first through holes 65, 66 are arranged at positions rotationally symmetrical by 180 degrees with respect to the rotation axis AX1. The first intermediate member 60 is screwed to the holding member 140 through the first through holes 65, 66. Specifically, a bolt 91 is inserted into the first through holes 65, 66 as shown in FIGS. 14 to 16. The bolt 91 is screwed into screw holes 143a, 144a of the holding member 140 described later. A predetermined clearance is ensured between the head of the bolt 91 and the first intermediate member 60, so that the first intermediate member 60 is held by the holding member 140 so as to be rotatable along the arc shape of the first through holes 65, 66. According to this configuration, the first intermediate member 60 can be held with a simple structure.

[0059] The first intermediate member 60 further includes a protrusion 67. The protrusion 67 extends forward from the front surface of the first intermediate member body 61. This protrusion 67 is used to bias the first intermediate member 60 toward the first blocking position (see FIGS. 6 and 14) by a spring 68 (see FIG. 9), which will be described later.

[0060] Next, the second intermediate member 70 will be described. As shown in FIG. 8, the second intermediate member 70 includes a base 71, a pressed portion 72, a blocking portion 73, support portions 74, 75, and a spring seat 78. The base 71 is a flat portion whose longitudinal direction is the front-rear direction and perpendicular to the up-down direction. The pressed portion 72 is a portion that is pressed upward by the mounting portion 320 of the cover 300 when the cover 300 is mounted to the second mounting portion 22, and is located at the front end of the second intermediate member 70. The pressed portion 72 has a flat plate shape parallel to the base 71. A step portion is formed between the base 71 and the pressed portion 72. This step portion can reduce the amount of displacement of the second intermediate member 70 when the cover 300 is mounted. Specifically, when the cover 300 is attached, the second intermediate member 70 is not displaced from the state in which the mounting portion 320 of the cover 300 is raised to the same position as the base 71 until the mounting portion 320 abuts against the pressed portion 72, so the amount of displacement of the second intermediate member 70 is smaller by the step difference compared to a configuration in which the pressed portion 72 is at the same vertical position as the base 71. Therefore, the displacement space of the second intermediate member 70 can be reduced. In other words, the vertical size of the grinder 10 can be prevented from increasing.

[0061] The blocking portion 73 is a portion that blocks the displacement path of the third intermediate member 80 when the cover 300 is not attached to the second mounting portion 22. The blocking portion 73 is located at the rear end of the second intermediate member 70, and extends upward from the rear end of the base 71. The blocking portion 73 has a flat plate shape perpendicular to the front-rear direction. When the cover 300 is not attached to the second mounting portion 22, the blocking portion 73 is located at a position that overlaps with the blocking portion 64 of the first intermediate member 60 when the side handle 200 is not attached, as seen in the front-rear direction, as shown in FIG.

[0062] The support parts 74, 75 are disposed in the vicinity of the blocking part 73, in front of the blocking part 73, so as to face each other in the left-right direction. The support parts 74, 75 extend from the base 71 in the left-right direction away from each other, and then bend and extend upward, forming a substantially L-shaped shape. The support parts 74, 75 are each formed with a second through hole 76, 77 penetrating the support parts 74, 75 in the front-rear direction. The second through holes 76, 77 are in the form of an elongated hole whose longitudinal direction is the up-down direction (i.e., the direction in which the cover 300 moves linearly when pressed). The second intermediate member 70 is screwed to the holding member 140 through the second through holes 76, 77. Specifically, a bolt 92 is inserted into the second through holes 76, 77 as shown in FIGS. 14 to 16. The bolt 92 is screwed into screw holes 145a, 146a of the holding member 140, which will be described later. By ensuring a predetermined clearance between the head of the bolt 92 and the support portions 74, 75, respectively, the second intermediate member 70 is held by the holding member 140 so as to be linearly movable along the second through holes 76, 77. According to this configuration, the second intermediate member 70 can be held with a simple configuration.

[0063] The spring seat 78 is provided so as to protrude upward from the base 71. A spring 79 (see FIG. 6) is held between the spring seat 78 and a spring seat 148 (see FIG. 9) of the holding member 140. The spring 79 biases the second intermediate member 70 toward the second blocking position (see FIGS. 6, 14, and 15).

[0064] Next, the holding member 140 will be described. As shown in Fig. 9, the holding member 140 includes an annular portion 141, a cylindrical portion 142, protruding portions 143 and 144, protruding portions 145 and 146, a spring seat 148, and a spring accommodating portion 149. The annular portion 141 has a disk shape centered on the rotation axis AX1 of the electric motor 31, and has a through hole formed in the center. A notch 147 is formed on the lower side of the annular portion 141 to ensure a displacement space for the second intermediate member 70.

[0065] The cylindrical portion 142 has a cylindrical shape extending rearward from the annular portion 141. The diameter of the cylindrical portion 142 is smaller than the diameter of the annular portion 141. A spring accommodating portion 149 is formed adjacent to the cylindrical portion 142 on the upper side of the cylindrical portion 142. The spring accommodating portion 149 is formed in an arc shape centered on the rotation axis AX1. A spring 68 that can expand and contract along the arc shape of the spring accommodating portion 149 is accommodated in the spring accommodating portion 149. The rear side of the spring accommodating portion 149 is open, and the protrusion 67 of the first intermediate member 60 is inserted into the spring accommodating portion 149 through this opening. One end of the spring 68 is supported by the inner surface of the spring accommodating portion 149 (a flat surface located at one end of the arc shape), and the other end of the spring 68 engages with the protrusion 67. This causes the first intermediate member 60 to be urged in the clockwise direction (in other words, toward the first blocking position).

[0066] The protruding portions 143, 144 are disposed so as to be spaced apart from each other in the left-right direction. The protruding portions 143, 144 extend rearward from the annular portion 141 at approximately the center of the annular portion 141 in the up-down direction. The protruding portions 143, 144 have screw holes 143a, 144a in which female threads are formed, respectively. The screw holes 143a, 144a extend frontward from the rear end surfaces of the protruding portions 143, 144. The bolts 91 are screwed into the screw holes 143a, 144a to attach the first intermediate member 60 to the holding member 140 in the above-mentioned manner (see FIG. 14).

[0067] The protruding parts 145, 146 are disposed below the protruding parts 143, 144 and spaced apart from each other in the left-right direction. The protruding parts 145, 146 have screw holes 145a, 146a in which female threads are formed, respectively. The screw holes 145a, 146a extend from the rear end surfaces of the protruding parts 145, 146 toward the front side. The bolts 92 are screwed into the screw holes 145a, 146a to attach the second intermediate member 70 to the holding member 140 in the above-mentioned manner (see FIG. 14). In order to hold the second intermediate member 70 forward of the first intermediate member 60, the length of the protruding parts 145, 146 in the front-rear direction is smaller than the length of the protruding parts 143, 144 in the front-rear direction.

[0068] The above-mentioned spring seat 148 is formed at the lower end of the cylindrical portion 142. With the first intermediate member 60 and the second intermediate member 70 attached, the holding member 140 is fitted into the gear housing 20 such that the outer periphery of the annular portion 141 and the inner periphery of the cylindrical portion 142 abut against the gear housing 20. This fixes the holding member 140 to the gear housing 20. When the first intermediate member 60 and the second intermediate member 70 are attached to a single holding member 140, the relative positions of the first intermediate member 60 and the second intermediate member 70 are naturally determined, so that there is no need to adjust the relative positions of the first intermediate member 60 and the second intermediate member 70 when assembling the grinder 10.

[0069] Next, the third intermediate member 80 and the conversion mechanism 100 will be described. As shown in Fig. 10, the third intermediate member 80 has a vertically extending portion 81 extending in the up-down direction and a rod-shaped horizontally extending portion 82 extending in an elongated manner forward from the lower end of the vertically extending portion 81. The horizontally extending portion 82 has a front end 83.

[0070] As shown in FIG. 1, the conversion mechanism 100 includes a first link member 110, a second link member 120, and a holding member 130. As shown in FIG. 11, the first link member 110 includes a pressing portion 111, engagement portions 112 and 113, and a through hole 114. The pressing portion 111 is located on the front side and upper side of the first link member 110. The pressing portion 111 has a circular arc-shaped curved surface facing the front side. The engagement portion 112 is a portion that extends in a U-shape toward the rear side at the left end of the first link member 110. The engagement portion 112 has a groove 112a that opens to the rear side. The engagement portion 113 is a portion that extends in a U-shape toward the rear side at the right end of the first link member 110. The engagement portion 113 has a groove 113a that opens to the rear side. The engagement portions 112, 113 are formed at positions where they completely overlap each other when viewed in the left-right direction. The through hole 114 is located on the front and lower side of the first link member 110, and penetrates the first link member 110 in the left-right direction.

[0071] 12, the second link member 120 includes a vertically extending portion 121 extending in the up-down direction, a first horizontally extending portion 122 extending forward from the lower end of the vertically extending portion 121, and a second horizontally extending portion 123 extending rearward from the upper end of the vertically extending portion 121. A support shaft 124 extending cylindrically in the left-right direction is formed at the front end of the first horizontally extending portion 122.

[0072] As shown in Fig. 13, the holding member 130 has a substantially cubic box shape. A spring seat 131 is formed on the inner surface of the front side of the holding member 130. A spring 132 is fixed to the spring seat 131 so as to be expandable in the front-rear direction within the holding member 130. The holding member 130 has two open sides, the rear side and the lower side, with an opening 134 formed on the rear side and an opening 135 formed on the lower side. The holding member 130 has a through hole 133 penetrating the left and right sides of the holding member 130 in the left-right direction.

[0073] As shown in FIG. 4, the first link member 110 is supported by the holding member 130 so as to be rotatable about a pin by inserting the pin through the through hole 114 of the first link member 110 and the through hole 133 of the holding member 130. The third intermediate member 80 is disposed so that the vertically extending portion 81 is located between the spring 132 and the pressing portion 111 of the first link member 110. Therefore, the third intermediate member 80 is biased toward the rear side by the spring 132. The second link member 120 is disposed so that the support shaft 124 is inserted into the groove 112a of the engagement portion 112 and the groove 113a of the engagement portion 113, and the rear end of the second horizontally extending portion 123 is placed on the working end 55 of the operating member 50. If the first link member 110 is attached to the holding member 130 and then the holding member 130 is assembled to the grinder 10, assembly becomes easier than when the first link member 110 is directly assembled to the housing of the grinder 10 or the like.

[0074] According to this conversion mechanism 100, the rotational motion of the operating member 50 in the approximately vertical direction can be changed to the linear motion of the third intermediate member 80 in the front-rear direction. Specifically, when the operating member 50 is displaced from the OFF position shown in FIG. 4 to the ON position shown in FIG. 3, the working end 55 of the operating member 50 is also displaced upward. At this time, as shown in FIG. 3, the second horizontally extending portion 123 of the second link member 120 is pushed upward by the working end 55 of the operating member 50. As a result, the entire second link member 120 moves linearly upward. At this time, since the support shaft 124 of the second link member 120 is inserted into the grooves 112a, 113a of the first link member 110, the engagement portions 112, 113 engaged with the support shaft 124 also receive an upward force. As a result, the first link member 110 rotates about the pin inserted into the through hole 114. At this time, the pressing portion 111 of the first link member 110 slides on the vertically extending portion 81 of the third intermediate member 80, and exerts a force directed forward on the vertically extending portion 81. As a result, the third intermediate member 80 moves linearly forward against the biasing force of the spring 132. On the other hand, when the operating member 50 returns from the ON position to the OFF position, the biasing force of the horizontally extending portion 82 returns the third intermediate member 80 to the position shown in FIG. 6. At this time, the first link member 110 is pushed rearward by the third intermediate member 80, so that it rotates and returns to its original position, and the second link member 120 engaged with the engagement portions 112 and 113 is also pulled downward and returns to its original position.

[0075] According to this conversion mechanism 100, even if the displacement direction of the operating member 50 differs from the displacement direction of the third intermediate member 80, the operating member 50 and the third intermediate member 80 can be interlocked. Therefore, the displacement direction of the operating member 50 is not subject to design constraints, so that an optimal type of operating member 50 can be adopted depending on the specifications of the grinder 10.

[0076] According to the above-described grinder 10, when the side handle 200 is not attached, the first intermediate member 60 is in the first blocking position (i.e., a position blocking the forward / rearward displacement path of the third intermediate member 80) shown in Fig. 6 and Fig. 14. In this state, when the user attempts to operate the operating member 50 from the OFF position to the ON position, as is clear from Fig. 6, the front end 83 of the third intermediate member 80 linked to the operating member 50 abuts against the blocking portion 64 of the first intermediate member 60, so that the third intermediate member 80 cannot be displaced further forward. Therefore, the operating member 50 cannot be displaced to the ON position either.

[0077] Furthermore, in a state where the cover 300 is not attached, the second intermediate member 70 is in the second blocking position (i.e., a position blocking the displacement path of the third intermediate member 80 in the front-rear direction) shown in Fig. 6 and Fig. 15. In this state, even if the user attempts to operate the operating member 50 from the OFF position to the ON position, even if the first intermediate member 60 is in the first non-blocking position (i.e., a position that does not block the displacement path of the third intermediate member 80 in the front-rear direction) shown in Fig. 14, as is clear from Fig. 6, the front end 83 of the third intermediate member 80 interlocked with the operating member 50 abuts against the blocking portion 73 of the second intermediate member 70, so that the third intermediate member 80 cannot be displaced further forward. Therefore, the operating member 50 cannot be displaced to the ON position either.

[0078] On the other hand, when the side handle 200 is attached, the first intermediate member 60 is pressed by the side handle 200 and rotated against the biasing force of the spring 68, and the blocking portion 64 of the first intermediate member 60 is displaced to a position where it does not block the displacement path of the third intermediate member 80 in the front-rear direction. Furthermore, when the cover 300 is attached, the second intermediate member 70 is pressed by the cover 300 and linearly moved against the biasing force of the spring 79, and the blocking portion 73 of the second intermediate member 70 is displaced to a position where it does not block the displacement path of the third intermediate member 80 in the front-rear direction. At this time, as is clear from FIG. 5, the third intermediate member 80 can be displaced forward without abutting against the first intermediate member 60 and the second intermediate member 70. Therefore, the operating member 50 can also be displaced to the on position. Therefore, a configuration in which the electric motor 31 can be driven only when both the side handle 200 and the cover 300 are attached can be realized using only a mechanical configuration without using a sensor.

[0079] Furthermore, the first intermediate member 60 is configured to rotate about the rotation axis AX1 when any of the pressed portions 62a to 62c is pressed by the side handle 200. Therefore, there is no need to ensure a displacement space for the first intermediate member 60 in the front-rear direction, and the size of the grinder 10 in the front-rear direction can be made compact.

[0080] Furthermore, when the cover 300 is attached, the second intermediate member 70 is pressed by the cover 300 (more specifically, the attachment portion 320) and moves linearly in the attachment direction (i.e., upward) of the cover 300. This eliminates the need for a direction changing mechanism, and allows for a simplified device configuration.

[0081] A second embodiment of the present invention will be described below with reference to Figures 17 to 21. Only the differences between the second embodiment and the first embodiment will be described below. As shown in Figure 17, a grinder 400 according to the second embodiment includes an operating member 450, a lock-off portion 443, a first intermediate member 460, and a second intermediate member 480.

[0082] As shown in FIG. 17, the operating member 450 is an elongated member extending in the front-rear direction, and is disposed below the motor housing 430 and the handle housing 440. The operating member 450 includes an action end 451, an engagement portion 452, a protrusion 453, and a protrusion 454. The action end 451 is a front end portion of the operating member 450, and has a smaller thickness (width in the vertical direction) than other portions. The action end 451 passes through a through hole 431 (see FIG. 20) formed in the motor housing 430 and reaches the inside of the motor housing 430. The engagement portion 452 is a portion for engaging with a lock-off portion 443 described later, and in this embodiment, is in the form of a protrusion protruding rearward at the rear end portion of the operating member 450. The protrusion 453 protrudes upward from an upper portion of the operating member 450. The protrusion 453 is disposed on the rear side of the operating member 450 in the front-rear direction. The protrusion 454 protrudes downward from a lower portion of the operating member 450. The protrusion 454 is disposed approximately in the center of the operating member 450 in the front-rear direction.

[0083] This operating member 450 can pivot up and down about a fulcrum that is a portion of the working end 451 that is located inside the through hole 431. When the operating member 450 is displaced upward from the OFF position shown in Fig. 17, which is the initial position, to the ON position shown in Fig. 19, the switch 441 is switched from the OFF state to the ON state via the pivot member 455.

[0084] Specifically, the pivot member 455 is disposed above the projection 453 of the operating member 450. The pivot member 455 is configured to be pivotable about a pin 458 supported by a boss of the handle housing 440, and includes a first portion 456 and a second portion 457 extending radially outward with respect to the pivot axis. The first portion 456 is disposed directly above the projection 453, and the second portion 457 is disposed higher than the first portion 456. Although not shown in the drawings, the pivot member 455 is biased counterclockwise by a biasing member (for example, a torsion spring) so that the first portion 456 abuts against the projection 453 of the operating member 450.

[0085] In a lock-off release state described later, when the user performs an operation of pressing the operating member 450 upward, the operating member 450 is pivoted upward. As a result, the protrusion 453 displaces the first portion 456 of the pivot member 455 upward against the biasing force of the biasing member, and the pivot member 455 is pivoted clockwise. As a result, the second portion 457 is also pivoted clockwise integrally. Then, when the operating member 450 pivots to the ON position shown in FIG. 19, the input member 442 of the switch 441 is pressed by the second portion 457 and pushed into the inside of the switch 441. As a result, the switch 441 is switched from the OFF state to the ON state. When the user releases the upward pressing operation on the operating member 450, the operating member 450 is pivoted downward by the biasing force of the biasing member that biases the pivot member 455, and returns to the OFF position shown in FIG. 17. 17 due to the biasing force of the biasing member, and the input member 442 also retracts from the switch 441. This causes the switch 441 to return from the on state to the off state.

[0086] The lock-off part 443 has a function similar to that of the lock-off switch 57 of the first embodiment. Specifically, the lock-off part 443 is configured to switch the status of the operating member 450 between a lock-off state in which the operating member 450 is prevented from being displaced from the OFF position to the ON position and a lock-off release state in which the operating member 450 is permitted to be displaced from the OFF position to the ON position by changing the engagement state with the operating member 450. In contrast to the lock-off switch 57 of the first embodiment, which is displaceable by itself, the lock-off part 443 has a fixed (i.e., non-displaceable) engagement structure. In this embodiment, the lock-off part 443 is formed on the rear side of the operating member 450 as a part of the handle housing 440 (more specifically, the rear and lower part).

[0087] As shown in Fig. 17, the lock-off portion 443 includes a base portion 444, an engagement portion 445, and a support portion 446. The base portion 444 is a portion that protrudes downward from the lower portion of the handle housing 440. The engagement portion 445 and the support portion 446 protrude forward from the base portion 444. The engagement portion 445 is located above the support portion 446, and a recess that is open to the front is formed between the engagement portion 445 and the support portion 446. The support portion 446 extends forward of the engagement portion 445.

[0088] 17, the operating member 450 is held in a non-detachable state so as to be displaceable in the front-rear and up-down directions by inserting the action end 451 into the through-hole 431 and placing the engagement portion 452 on the support portion 446. The operation member 450 is manually displaced in the front-rear and up-down directions by the user. The user can easily displace the operation member 450 in the front-rear and up-down directions by hooking their finger on the protrusion 454.

[0089] 17, the first intermediate member 460 is disposed forward of the operating member 450. The first intermediate member 460 has the same or similar configuration as the first intermediate member 60 of the first embodiment, and is configured to be displaced by being pressed directly or indirectly by a side handle (not shown) as an accessory when the side handle is attached to an attachment portion (not shown).

[0090] As shown in Figs. 17 and 20, the second intermediate member 480 is disposed between the first intermediate member 460 and the operating member 450 in a manner displaceable in the front-rear direction. As shown in Fig. 20, in this embodiment, the second intermediate member 480 is a rod-shaped member extending in the front-rear direction. An expanded diameter portion 481 having a larger diameter than other portions is formed at the rear end of the second intermediate member 480. The "diameter" here refers to the length around the front-rear direction, and the cross-sectional shape of the second intermediate member 480 and / or the expanded diameter portion 481 in a direction perpendicular to the front-rear direction is not limited to a circle.

[0091] As shown in FIG. 20, a coil spring 485 is disposed around the second intermediate member 480 as a biasing member. The coil spring 485 is held in a compressed state between the baffle plate 432 fitted inside the motor housing 430 and the enlarged diameter portion 481. The second intermediate member 480 is always biased backward, that is, toward the operating member 450, by the coil spring 485. Therefore, regardless of the position of the second intermediate member 480 in the front-rear direction, the enlarged diameter portion 481 always abuts against the working end portion 451 of the operating member 450 in the front-rear direction. When the user displaces the operating member 450 forward, the second intermediate member 480 is pushed forward by the operating member 450 against the biasing force of the coil spring 485, and is displaced forward together with the operating member 450. On the other hand, when the user releases the force displacing the operating member 450 forward, the operating member 450 and the second intermediate member 480 are returned to their original positions by the biasing force of the coil spring 485. In this manner, the second intermediate member 480 is configured to move in conjunction with the displacement of the operating member 450 in the front-rear direction.

[0092] The operation of such a grinder 400 will be described below. First, as shown in FIG. 17, when the operating member 450 is in the OFF position and in the locked-off state, the engaging portion 452 of the operating member 450 is accommodated in a recess between the engaging portion 445 of the lock-off portion 443 and the support portion 446. The position of the operating member 450 at this time is also called the locked-off position. When the operating member 450 is in the locked-off position, the engaging portion 445 is located directly above the engaging portion 452, so that even if the user tries to press the operating member 450 upward, the engaging portion 452 abuts against the engaging portion 445, and the upward displacement of the operating member 450 is restricted. Therefore, the operating member 450 is prevented from displacing from the OFF position (see FIG. 17) to the ON position (see FIG. 19). When the operating member 450 is in the OFF position and in the locked-off state, the second intermediate member 480 is not pressed forward by the operating member 450 and is located in the position shown in FIG. 20. The position of the second intermediate member 480 at this time is also referred to as a first corresponding position.

[0093] In order to change the operating member 450 from the locked-off state to the unlocked state, the user needs to displace the operating member 450 forward. However, as shown in FIG. 20, in a state where the side handle is not attached to the attachment portion, the first intermediate member 460 is located in front of the second intermediate member 480. Therefore, when the user tries to displace the operating member 450 forward, the tip 482 of the second intermediate member 480 linked to the operating member 450 abuts against the first intermediate member 460, so that the forward displacement of the second intermediate member 480 (and thus the operating member 450) is restricted. In this way, the first intermediate member 460 prevents the status of the operating member 450 from being switched from the locked-off position state to the unlocked state by the inter-member abutment (here, the abutment between the first intermediate member 460 and the tip 482 of the second intermediate member 480). In other words, the first intermediate member 460 blocks the displacement path along which the second intermediate member 480 is displaced forward from the first corresponding position.

[0094] On the other hand, as shown in FIG. 21, in a state where the side handle is attached to the attachment portion, the first intermediate member 460 is displaced in the same manner as in the first embodiment, and the second intermediate member 480 is not blocked from displacing forward from the first corresponding position (in the cross section shown in FIG. 21, the first intermediate member 460 is displaced to a position not shown). That is, the above-mentioned inter-member abutment does not occur, and the operation member 450 and the second intermediate member 480 are allowed to displace forward. Therefore, the user can displace the operation member 450 and the second intermediate member 480 forward to the positions shown in FIG. 18 and FIG. 21 against the biasing force of the coil spring 485. At this time, as shown in FIG. 18, the engagement portion 452 of the operation member 450 is supported on the support portion 446 of the lock-off portion 443, but the engagement portion 445 does not exist directly above the engagement portion 452. Therefore, the operation member 450 is in a state where it can be displaced upward (that is, the lock-off release state). The position of the operating member 50 at this time is also called the lock-off release position, and the position of the second intermediate member 480 is also called the second corresponding position.

[0095] In this way, after the operating member 450 is in the OFF position and in the lock-off release state, when the user displaces the operating member 450 upward, the switch 441 becomes in the ON state via the pivot member 455 in the above-mentioned manner, as shown in Fig. 19. On the other hand, when stopping the driving of the grinder 400, when the user releases the upward displacement operation of the operating member 450, the operating member 450 returns from the ON position (see Fig. 19) to the OFF position (see Fig. 18) as described above. At this time, the operating member 450 returns from the lock-off release position (see Fig. 18) to the lock-off position (see Fig. 17) by the biasing force of the coil spring 485, and the second intermediate member 480 returns from the second corresponding position to the first corresponding position.

[0096] According to the above-mentioned grinder 400, a configuration that allows the electric motor to be driven only when the side handle is attached can be realized by using only a mechanical structure without using a sensor. In addition, since the displacement of the operating member 450 accompanying the above-mentioned unlocking operation is easy for a user to recognize, when the electric motor cannot be driven despite the operation of displacing the operating member 450 from the OFF position to the ON position, the user can easily realize that the reason is not a failure of the switch 441, but that the unlocking operation cannot be performed because the side handle is not attached.

[0097] Moreover, according to the grinder 400, the second intermediate member 480 that is interlocked with the operating member 450 is disposed between the first intermediate member 460 and the operating member 450. This allows the first intermediate member 460 and the operating member 450 to be laid out apart from each other, improving the design freedom of the grinder 400. However, the second intermediate member 480 may be omitted. In this case, the working end 451 of the operating member 450 may extend to the position of the first intermediate member 460 in the front-rear direction, and the first intermediate member 460 may block the displacement path of the working end 451 only when the side handle is not attached.

[0098] In an alternative embodiment, the grinder 400 may be configured such that the operating member 450 can be switched from the locked-off state to the unlocked state only when both the side handle and the cover are attached, similar to the first embodiment. Alternatively, the grinder 400 may be configured such that the operating member 450 can be switched from the locked-off state to the unlocked state only when the cover is attached.

[0099] In a further alternative embodiment, a displaceable lock-off member may be provided as the lock-off member instead of the lock-off portion 443 which is a fixed engagement structure. In this case, a second intermediate member may be provided between the first intermediate member 460 and the lock-off member for preventing the lock-off member from displacing from the lock-off position to the lock-off release position only when the side handle is not attached.

[0100] Although the embodiment of the present invention has been described above, the above-mentioned embodiment is for facilitating understanding of the present invention and does not limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof. In addition, any combination or omission of each element described in the claims and specification is possible within the scope of solving at least a part of the above-mentioned problems or achieving at least a part of the effects.

[0101] For example, the shapes and forms of the components of the grinder 10 described above are merely examples, and any changes are possible as long as the functions of the components are ensured. For example, the pressed parts 62a to 62c of the first intermediate member 60 may protrude to the front or rear side instead of protruding radially outward. Alternatively, the blocking part 64 may be omitted, and a through hole through which the third intermediate member 80 can pass when the first intermediate member 60 is in the first non-blocking position may be formed in the first intermediate member body 61. In this case, when the first intermediate member 60 is in the first non-blocking position, the first intermediate member body 61 functions to block the displacement path of the third intermediate member 80. Alternatively, at least a part of the third intermediate member 80 (for example, the horizontally extending part 82) may be a wire.

[0102] Furthermore, the first intermediate member 60 may be indirectly pressed by the side handle 200 when the side handle 200 is attached. In other words, an additional member that is pressed and displaced by the side handle 200 may be provided, and the first intermediate member 60 may be displaced by this additional member. Similarly, the second intermediate member 70 may be indirectly pressed by the cover 300 when the cover 300 is attached.

[0103] Furthermore, instead of being configured to rotate when the side handle 200 is attached, the first intermediate member 60 may be configured to be pressed by the side handle 200 and tilted when the side handle 200 is attached. For example, the first intermediate member 60 may have a support shaft on the upper side of the first intermediate member 60, and when the side handle 200 is attached, the first intermediate member 60 may be tilted around the support shaft so that the lower end of the first intermediate member 60 approaches the front side.

[0104] Furthermore, the above-described embodiment is not limited to the grinder 10, but can be applied to any tool that is equipped with a prime mover and to which two types of accessories can be detachably attached. [Explanation of symbols]

[0105] 10,400...Grinder 20...Gear housing 22...Second mounting part 23...Small bevel gear 24...Large bevel gear 25...Spindle 26...Inner flange 27...Lock nut 28... Tip tool 29a, 29b, 29c...First mounting portion 30,430...Motor housing 31...Electric motor 32...Motor shaft 40,440...Handle housing 41,441...Switch 42,442... Input member 50,450...Operating parts 51...Spindle 52...protrusion 53...Spring seat 54...Spring 55...Working end 57...Lock off switch 60...First intermediate member 61...First intermediate member body 62a, 62b, 62c...Pressed part 63a,63b,63c...Pressed surface 64...Cutting section 65...First through hole 67...protrusion 68...Spring 70...Second intermediate member 71...Bass 72...Pressure receiving part 73...Cutting section 74...Support part 76...Second through hole 78...Spring seat 79...Spring 80...Third intermediate member 81...Vertical extension part 82...Horizontal extension part 83...front end 91,92...Volts 100...Conversion mechanism 110...First link member 111...Pressing part 112, 113...Engagement part 112a,113a...Groove 114...Through hole 120...Second link member 121...Vertical extension part 122...first horizontal extension 123...Second horizontal extension 124...Spindle 130...Retaining member 131...Spring seat 132...Spring 133...Through hole 134,135...Aperture 140...Retaining member 141...Ring section 142...Cylindrical section 143,144,145,146...protrusion 143a, 144a, 145a, 146a...Screw holes 147...Notch 148...Spring seat 149...Spring housing 200...Side handle 210...Grip section 220...Mounting part 300...Cover 310...Cover body 320...Mounting part 431...Through hole 432...Baffle plate 443...Lock-off section 444...Base 445...Engagement part 446...Support part 451...Working end 452...Engagement part 453,454...protrusion 455...Pivot member 456...First part 457...Second part 458...pin 460...First intermediate part 480...Second intermediate part 481... Expanded diameter section 482...Tip 485... Coil spring AX1, AX2...Rotation axis

Claims

1. A tool, The prime mover, a switch for driving the prime mover; an operating member configured to be displaceable in a first direction between an OFF position that turns the switch to an OFF state and an ON position that turns the switch to an ON state; A mounting portion configured to removably mount an accessory; a lock-off unit configured to switch a status of the operating member between a lock-off state in which the operating member is prevented from being displaced from the OFF position to the ON position and an unlocked state in which the operating member is permitted to be displaced from the OFF position to the ON position by changing an engagement state with the operating member; a first intermediate member configured to be directly or indirectly pressed against the accessory and displaced when the accessory is attached to the attachment portion; and Equipped with The first intermediate member includes: When the accessory is not attached to the attachment portion, the lock-off lever is positioned at a blocking position where a release operation for switching the lock-off state to the lock-off release state is blocked by contact between members, When the accessory is attached to the attachment portion, the attachment portion is in an allowable position that allows the release operation because no contact between the members occurs. tool.

2. 2. The tool according to claim 1, The lock-off portion has a fixed engagement structure, the operating member is configured to be displaceable in a second direction different from the first direction from a lock-off position corresponding to the lock-off state to a lock-off release position corresponding to the lock-off release state, The release operation is to displace the operating member from the lock-off position to the lock-off release position. tool.

3. 3. The tool according to claim 2, a second intermediate member configured to move in conjunction with a displacement of the operating member in the second direction between a first corresponding position corresponding to the lock-off position of the operating member and a second corresponding position corresponding to the lock-off release position of the operating member, The first intermediate member is configured to be displaced so as to block a displacement path of the second intermediate member from the first corresponding position to the second corresponding position when in the blocking position, and not to block the displacement path of the second intermediate member from the first corresponding position to the second corresponding position when in the allowing position. tool.

4. A tool according to any one of claims 1 to 3, the prime mover being an electric motor; the tool is a grinder having a tool tip configured to be rotated by the electric motor, The accessory is a side grip. tool.

5. The tool according to claim 4, the mounting portion includes at least two side grip mounting portions for selectively mounting the side grips; The first intermediate member includes: a single member provided in common to the at least two side grip attachment portions; The gripper has at least one pressed portion that is pressed directly or indirectly against the side grip when the side grip is attached to one side grip attachment portion arbitrarily selected from the at least two side grip attachment portions, and is configured to be displaced when the at least one pressed portion is pressed. tool.

6. 6. The tool according to claim 5, the first intermediate member comprises a first intermediate member body having a ring or partial ring shape; The at least two side grip attachment portions are located at spaced apart positions circumferentially about the ring or partial ring. tool.

7. 7. The tool according to claim 6, The first intermediate member is configured to rotate about a rotation axis when the at least one pressed portion is pressed. tool.

8. The tool according to claim 7, The at least one pressed portion is protruding radially outward from the first intermediate member body, at least two positions corresponding to the positions of the at least two side grip attachment parts, tool.

9. A tool according to claim 8, which depends on at least claim 3, the first intermediate member includes a blocking portion that blocks the displacement path of the second intermediate member when the first intermediate member is in the blocking position; The blocking portion protrudes radially outward from the first intermediate member body. tool.

10. A tool according to any one of claims 7 to 9, the first intermediate member body has a first through hole having an arc shape centered on the rotation axis, The first intermediate member is screwed through the first through hole so as to be rotatable along the arc shape. tool.

11. A tool according to any one of claims 5 to 10, The at least one pressed portion has a pressed surface that is angled with respect to the longitudinal direction of the side grip such that the first intermediate member is displaced in a direction different from the longitudinal direction of the side grip when the side grip is attached to the one side grip attachment portion. tool.

12. A tool according to any one of claims 4 to 11, The rotation axis of the electric motor and the rotation axis of the tool bit intersect with each other. tool.

13. A tool according to claim 3 and any one of claims 4 to 12 which includes at least claim 3 as a dependent, The attachment portion is disposed on a first side in a longitudinal direction of the tool, The operating member is disposed on a second side opposite to the first side, The second intermediate member is an elongated member extending in the longitudinal direction. tool.

14. A tool according to any one of claims 4 to 12 and claim 13, which depends on at least claim 4, a handle housing for being grasped by a user; a motor housing that accommodates the electric motor; Equipped with The handle housing is located on the opposite side of the motor housing to the tool bit in a direction in which a rotation axis of the electric motor extends. tool.

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