tool

Abstract

To improve a power tool that can be attached with and detach an accessory.SOLUTION: A power tool is equipped with a motor configured to provide driving force to a tip end tool, a braking mechanism that is disposed in a driving force transmission path from the motor to the tip end tool, and is configured to brake the driving of the tip end tool, at least one attaching portion that is configured to be attached with an accessory, and a regulating member that is configured to be directly or indirectly pressed by the accessory to be displaced when attaching the accessory to any of at least the one attaching portion. The regulating member is located at a preventive position where releasing operation in a braking state by the braking mechanism is prevented by inter-member abutting, while the accessory is not attached to any of at least the one attaching portion. The regulating member is located at a permissible position where the releasing operation in the braking state is permitted because the inter-member abutting does not occur, while the accessory is attached to any of at least the one attaching portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to power tools. [Background technology]

[0002] A variety of accessories may be detachably attached to a power tool. For example, in a grinder having a tool bit configured to rotate, a cover (also called a wheel cover, disc cover, blade case, etc.) for covering a part of the tool bit and a side handle for a user to hold with one hand when holding the grinder handle with the other hand are available as detachable accessories.

[0003] For such grinders, there is a need to prevent them from being used without an accessory attached. For example, Patent Document 1 listed below discloses a grinder equipped with a sensor that detects whether a cover is attached and a controller that prohibits rotation of the tool bit when the cover is not attached. Patent Document 2 listed below also discloses a grinder equipped with a sensor that detects whether a cover is attached and a sensor that detects whether a side handle is attached. Patent Document 3 listed below discloses a grinder equipped with a blocking member that is displaced depending on whether an accessory is attached. In this grinder, when an accessory is not attached, a mechanical element that engages with an operating member for turning the switch on abuts against the blocking member, preventing the operating member from moving to the on position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 051893 [Patent Document 2] US Patent Application Publication No. 2018 / 272494 [Patent Document 3] US Patent Application Publication No. 2018 / 0326554 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is room for improvement in the above technologies. For example, in the technologies described in Patent Documents 1 and 2, there is a risk that the attachment of a cover or a side handle cannot be detected if the sensor breaks down or if the sensor's sensitivity is reduced due to the accumulation of dust. Furthermore, the technology described in Patent Document 3 only restricts the displacement of the operating member when no accessories are attached, so there is room for improvement in terms of more reliably restricting the drive of the tool bit. These points are not limited to grinders, but are common to all power tools with detachable accessories. [Means for solving the problem]

[0006] This specification discloses a power tool. The power tool may include a motor configured to provide a driving force to a tool bit, a braking mechanism disposed in a driving force transmission path from the motor to the tool bit and configured to brake the driving of the tool bit, at least one mounting portion configured to detachably mount an accessory, and a restricting member configured to be directly or indirectly pressed against the accessory and displaced when the accessory is mounted to any of the at least one mounting portion. The restricting member may be positioned in a blocking position that prevents a release operation of the braking mechanism by inter-member contact when the accessory is not mounted to any of the at least one mounting portion, and in a permitting position that allows a release operation of the braking state due to the absence of inter-member contact when the accessory is mounted to any of the at least one mounting portion.

[0007] This power tool allows the tool bit to be driven only when an accessory is attached, and this can be achieved using only a mechanical structure without using a sensor. Furthermore, when no accessory is attached, the brake mechanism's release operation is prevented by the restricting member. In other words, the power tool remains in a braked state. In other words, the tool bit is forced to stop regardless of the on / off state of the switch for driving the tool bit. Therefore, when no accessory is attached, the tool bit can be more reliably restricted from being driven. [Brief explanation of the drawings]

[0008] [Figure 1] 3 is a longitudinal cross-sectional view of the grinder according to the first embodiment of the present invention taken along line AA in FIG. 2, in which the side handle is not attached, the tool bit is in a braked state, and the operating member is in an off position. [Figure 2] FIG. 2 is a cross-sectional view of the grinder taken along line BB in FIG. 1. [Figure 3] 2 is a partial cross-sectional view of the grinder taken along line CC in FIG. 1. [Figure 4] FIG. 2 is a partial cross-sectional view of the grinder taken along line DD in FIG. 1. [Figure 5] FIG. 2 is a vertical cross-sectional view of the grinder taken along line EE in FIG. [Figure 6] FIG. 2 is a vertical cross-sectional view of the grinder taken along line FF in FIG. 1. [Figure 7] FIG. 2 is a partially enlarged view of the grinder shown in FIG. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. 2 is a longitudinal cross-sectional view of the grinder corresponding to FIG. 1, with the side handle attached, the tool bit in a brake-released state, and the operating member in an ON position. [Figure 11] 6 is a longitudinal sectional view of the grinder corresponding to FIG. 5, showing the side handle attached. FIG. [Figure 12] 7 is a longitudinal sectional view of the grinder corresponding to FIG. 6, showing the side handle attached. [Figure 13] 8 is a partial enlarged view of the grinder corresponding to FIG. 7, showing the side handle attached. [Figure 14] FIG. 10 is a longitudinal sectional view of a grinder according to a second embodiment of the present invention, in which the side handle is not attached, the tool bit is in a braked state, and the operating member is in an off position in a locked-off state. [Figure 15] 15 is a longitudinal cross-sectional view of the grinder corresponding to FIG. 14, in which the side handle is attached, the tool bit is in the brake-released state, and the operating member is in the off position in the lock-off released state. [Figure 16] FIG. 15 is a longitudinal cross-sectional view of the grinder corresponding to FIG. 14, in which the side handle is attached, the tool bit is in the brake-released state, and the operating member is in the on position with the lock-off released. [Figure 17] FIG. 15 is a partially enlarged view of the grinder shown in FIG. [Figure 18] FIG. 16 is a partially enlarged view of the grinder shown in FIG. [Figure 19] FIG. 15 is a partial cross-sectional view of the grinder taken along line GG in FIG. 14. [Figure 20] FIG. 16 is a partial cross-sectional view of the grinder taken along line GG in FIG. 15. DETAILED DESCRIPTION OF THE INVENTION

[0009] In one or more embodiments, the at least one mounting portion may include multiple mounting portions, making the above-described embodiments applicable to power tools that allow accessories to be selectively attached to multiple mounting locations.

[0010] In one or more embodiments, the restricting member may be a single member that is commonly provided for the multiple mounting portions. With this configuration, the single restricting member is shared by the multiple mounting portions, thereby reducing the number of parts and simplifying the device structure.

[0011] In one or more embodiments, the multiple mounting portions may include a first mounting portion and a second mounting portion. The permissible positions may include a first permissible position and a second permissible position. The restricting member may be configured to displace from the blocking position in a first direction to the first permissible position when the accessory is attached to the first mounting portion, and to displace from the blocking position in a second direction opposite to the first direction to the second permissible position when the accessory is attached to the second mounting portion. This configuration provides a rational structure for sharing a single restricting member for multiple mounting portions. In other words, a configuration in which the restricting member is pressed against an accessory to allow the release of a braked state when the accessory is attached to any of the multiple mounting portions can be realized with a simple device structure.

[0012] In one or more embodiments, the power tool may further include an intermediate member configured to be pressed and displaced by an accessory when the accessory is attached to any of the at least one mounting portions. The regulating member may be configured to be pressed and displaced by the intermediate member when the accessory is attached to any of the at least one mounting portions. This configuration provides a rational structure for displacing the regulating member to allow a release operation from the braked state when an accessory is attached to any of the at least one mounting portions. In other words, the regulating member can be made smaller than when the regulating member is directly pressed by the accessory when the accessory is attached to any of the at least one mounting portions, thereby reducing space constraints when designing the layout within the power tool.

[0013] In one or more embodiments, the motor may include a motor shaft. The power tool may further include a final output shaft configured to transmit driving force from the motor shaft and to which a tool accessory can be attached. The braking mechanism may be disposed around the motor shaft. With this configuration, the braking mechanism is not disposed around the final output shaft, thereby reducing the size and weight of the final output shaft. In this type of power tool, a user typically grips a portion other than the final output shaft during use. Therefore, with this configuration, the reduction in size and weight of the final output shaft improves the ease of handling of the power tool.

[0014] In one or more embodiments, the braking mechanism includes: a braked member that is fixed to the motor shaft and arranged to surround the motor shaft in a circumferential direction; a braking position that is configured to be pressed against the braked member to achieve a braking state and abuts against the braked member; covered and a non-braking position where the brake member is spaced from the braking member, a biasing member that biases the brake member toward the braking position, and a brake release member that is configured to press the brake member from the braking position toward the non-braking position against the biasing force of the biasing member to displace the brake member. With this configuration, it is possible to provide a braking function while preventing the power tool from becoming larger.

[0015] In one or more embodiments, the power tool may further include a switch for driving the motor and an operating member configured to be movable between an OFF position that turns the switch OFF and an ON position that turns the switch ON. The brake release member may be configured to operate in conjunction with the movement of the operating member between the OFF position and the ON position. This configuration facilitates timing adjustment between the release of the brake state and the ON operation of the switch (i.e., the operation of moving the operating member from the OFF position to the ON position). Specifically, a configuration can be easily realized that reliably releases the brake state before the switch is turned ON.

[0016] In one or more embodiments, the power tool may further include a link member configured to move in conjunction with the displacement of the operating member between the OFF position and the ON position. The link member may be configured to move when the operating member is displaced from the OFF position to the ON position, to press the switch so that the switch is turned on, and to press the brake release member so that the brake is released. This configuration makes it easy to ensure that the brake is released before the switch is turned on.

[0017] In one or more embodiments, the power tool may further include a switch for driving the motor, an operating member configured to be movable between an OFF position that turns the switch OFF and an ON position that turns the switch ON, and a lock-off unit configured to switch the status of the operating member between a locked-off state in which the operating member is prevented from moving from the OFF position to the ON position and an unlocked state in which the operating member is allowed to move from the OFF position to the ON position by changing the engagement state with the operating member. The brake release member may be configured to be linked to an operation for switching between the locked-off state and the unlocked state. With this configuration, when the status of the operating member is switched from the locked-off state to the unlocked state (at this point, the switch is in the OFF state), the brake release member releases the brake state. Therefore, a configuration can be easily realized that reliably releases the brake state before the switch is turned ON.

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. In the following embodiments, a handheld electric disc grinder (hereinafter simply referred to as a grinder) will be exemplified as a power tool.

[0019] First, a first embodiment of the present invention will be described. As shown in FIG. 1, a grinder 10 according to the first embodiment is configured to rotate a substantially disk-shaped tool bit 28 attached to a spindle 25 serving as a final output shaft. The spindle 25 is rotated by a rotational drive force provided by an electric motor 31 serving as a prime mover. Grindstones, rubber pads, brushes, blades, and the like are available as tool bits 28 that can be attached to the grinder 10. A user selects an appropriate tool bit 28 depending on the desired processing task and attaches it to the grinder 10. The grinder 10 can perform processing tasks such as grinding, polishing, and cutting on a workpiece depending on the type of tool bit 28.

[0020] 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 bit 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 bit 28) extends is defined as the up-down direction of the grinder 10. In the up-down direction, the side where the tool bit 28 is located is defined as the bottom side, and the opposite side is defined as the top 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 back 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.

[0021] 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 housed in the motor housing 30, which is located between the gear housing 20 and the handle housing 40 in the front-to-rear direction, i.e., the longitudinal direction of the grinder 10. The electric motor 31 is configured to be driven by externally supplied power (although in this embodiment this is AC power, it may also be DC power).

[0022] The gear housing 20 accommodates a mechanism for transmitting the rotational driving force of the electric motor 31 to the tool bit 28. Specifically, the gear housing 20 accommodates a small bevel gear 23, a large bevel gear 24, and a spindle 25. 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 rotatably supported about a rotation axis AX2 by bearings spaced apart 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 an attachment portion 22 at its lower end for detachably attaching a cover 300. The attachment portion 22 has a cylindrical shape extending in the vertical direction. The spindle 25 extends vertically within the gear housing 20, and extends from the gear housing 20 (more specifically, the mounting portion 22) on the lower side.

[0023] 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 on the spindle 25 below the inner flange 26, and a lock nut 27 is attached to the male thread. A tool bit 28 is sandwiched between the inner flange 26 and the lock nut 27, and the position of the tool bit 28 relative to the spindle 25 is fixed by tightening the lock nut 27.

[0024] The handle housing 40 is a portion that the user holds with one hand when using the grinder 10. The handle housing 40 has a cylindrical shape that extends generally in the front-to-rear direction. A switch 41 for driving the electric motor 31 is housed inside the handle housing 40. An operating member 50 is provided on the lower side of the handle housing 40 and is configured to be displaceable between an OFF position (see FIG. 1) that turns the switch 41 off and an ON position (see FIG. 10) that turns the switch 41 on.

[0025] 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 via the small bevel gear 23 and the large bevel gear 24 while being decelerated. 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 tool bit 28 fixed by the inner flange 26 and the lock nut 27 rotates together with the spindle 25. As is clear from the above description, the motor shaft 32, the small bevel gear 23, the large bevel gear 24, and the spindle 25 form a drive force transmission path from the electric motor 31 to the tool bit 28.

[0026] 1, 2, and 7, the grinder 10 further includes a braking mechanism 60 configured to brake the driving of the bit 28. In this embodiment, the braking mechanism 60 is disposed around the motor shaft 32 in the drive force transmission path from the electric motor 31 to the bit 28. Specifically, the braking mechanism 60 is disposed in a brake holder 61 that is disposed between the gear housing 20 and the motor housing 30 in the front-rear direction. The braking mechanism 60 includes a brake plate 62, a braking member 63, a brake shoe 64, a biasing member 65, and a brake release member 66.

[0027] As shown in Fig. 7, the brake plate 62 includes a cylindrical portion 62a and a braked portion 62b. The cylindrical portion 62a extends in the front-rear direction coaxially with the rotation axis AX1 so as to circumferentially surround the motor shaft 32. The cylindrical portion 62a is fixed to the motor shaft 32 by press fitting. The braked portion 62b is a flange-shaped portion that extends radially outward from the rear end of the cylindrical portion 62a relative to the rotation axis AX1. The front end surface of the braked portion 62b is formed as a flat surface that is perpendicular to the rotation axis AX1.

[0028] As shown in FIG. 7, the brake member 63 is an annular member disposed to surround the motor shaft 32. The brake member 63 includes a disc 63a extending in the radial direction, an inner protrusion 63b, and an outer protrusion 63c. The inner protrusion 63b protrudes forward from the disc 63a along the inner edge of the disc 63a. The outer protrusion 63c is a portion extending forward from the disc 63a and is formed only on the bottom portion of the outer periphery of the disc 63a. The outer protrusion 63c extends further forward than the inner protrusion 63b.

[0029] 7, the brake shoe 64 is fixed to the rear end surface of the disc 63a of the braking member 63. The brake shoe 64 is a disc-shaped member that circumferentially surrounds the cylindrical portion 62a and is disposed in a position that overlaps with the braked portion 62b when viewed in the front-rear direction. The disc 63a of the braking member 63 extends radially outward beyond the brake shoe 64.

[0030] As shown in FIG. 7 , the biasing member 65 is in the form of a coil spring in this embodiment. The biasing member 65 is disposed in a compressed state between the bearing support 34, which supports the bearing 33 that supports the motor shaft 32 at the front side, and the brake member 63. The biasing member 65 is disposed so that the cylindrical portion 62a of the brake plate 62 penetrates through its interior. The front end of the biasing member 65 is fitted into the protruding portion 35 of the bearing support 34 (which protrudes cylindrically rearward from the bearing support 34 in the circumferential direction), and the rear end of the biasing member 65 is fitted radially outward of the inner protruding portion 63b of the brake member 63. Therefore, the position of the biasing member 65 in the direction perpendicular to the rotation axis AX1 is fixed, and the brake member 63 and the brake shoe 64 are also maintained in appropriate positions in the direction perpendicular to the rotation axis AX1. With this configuration, the brake member 63 and the brake shoe 64 are configured to be displaceable in the front-rear direction depending on the compression amount of the biasing member 65.

[0031] The biasing member 65 constantly biases the brake member 63 and the brake shoe 64 rearward (toward a braking position, which will be described later). Therefore, when no external force is acting on the brake member 63, the brake shoe 64 abuts against the front end surface of the braked portion 62b of the brake plate 62, pressing the braked portion 62b rearward. This allows the braking function of the braking mechanism 60 to be exerted. When the brake shoe 64 is pressed against the braked portion 62b (hereinafter referred to as the braking state), the rotation of the tool bit 28 is stopped even if current is supplied to the electric motor 31. The position of the brake member 63 and the brake shoe 64 in the braking state is also referred to as the braking position (shown in FIGS. 1 and 7).

[0032] In this braking mechanism 60, braking can be released by displacing the brake member 63 and the brake shoe 64 forward. The released state of the brake is also referred to as the brake-released state. Specifically, a brake release member 66 that can be displaced in the front-rear direction is disposed behind the brake member 63. When the brake release member 66 is displaced forward, it abuts against the lower part of the disc 63a of the brake member 63 and presses the brake member 63 forward. As a result, as shown in FIG. 13 , the brake member 63 and the brake shoe 64 are displaced forward against the biasing force of the biasing member 65. As a result, the brake shoe 64 and the braked portion 62b of the brake plate 62 are separated, and braking is released. The position of the brake member 63 and the brake shoe 64 in the brake-released state is also referred to as the non-braking position (shown in FIGS. 10 and 13 ). The mechanism for displacing the brake release member 66 in the front-rear direction will be described later. According to the braking mechanism 60 described above, the components are compactly arranged around the motor shaft 32, so that the braking function can be provided while preventing the grinder 10 from becoming too large.

[0033] The grinder 10 further includes a side handle 200 (see FIGS. 10-12) and a cover 300 (see FIG. 1) as accessories. The side handle 200 is provided so that the user can hold it with the hand opposite to the hand that holds 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 (not shown) for the user to hold, an attachment portion 210 for attaching to the gear housing 20, and a pressing portion 220. The attachment portion 210 has a cylindrical shape extending in the longitudinal direction of the side handle 200 and extends from one end of the grip portion in the longitudinal direction of the side handle 200. A male screw is formed on the outer peripheral surface of the attachment portion 210. The pressing portion 220 (see FIG. 11) is a cylindrical portion that extends from the tip of the attachment portion 210 and has a smaller outer diameter than the attachment portion 210. The function of the pressing portion 220 will be described later.

[0034] 2, the gear housing 20 has a plurality of (two in this embodiment) mounting portions 29a, 29b for detachably mounting the side handle 200. The mounting portions 29a, 29b are arranged at the same position in the front-rear direction and at positions spaced apart from each other in the circumferential direction about the rotation axis AX1. More specifically, the first mounting portion 29a is formed on the left side surface of the gear housing 20, and the second mounting portion 29b is formed on the right side surface of the gear housing 20. Each of the first mounting portion 29a and the second mounting portion 29b is in the form of a through hole that connects the inside and outside of the gear housing 20. A female thread that screws onto the male thread of the mounting portion 210 is formed on the inner surface that defines the through hole.

[0035] The side handle 200 can be attached to the gear housing 20 by screwing the attachment portion 210 of the side handle 200 into one of the two attachment portions 29a, 29b. The user can arbitrarily select the attachment location of the side handle 200 from attachment portions 29a, 29b 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, two attachment portions 29a, 29b are provided, but the number of attachment portions for attaching the side handle 200 is not particularly limited and may be any number equal to or greater than one.

[0036] As shown in FIG. 1 , the cover 300 includes a cover body 310 that covers a portion of the tool bit 28 and an attachment portion 320 for attachment to the attachment 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, lower surface, and peripheral surface between the upper and lower surfaces of the tool bit 28. However, depending on the type of tool bit 28 used, the cover body 310 may cover only the upper surface and peripheral surface. The attachment portion 320 has an open, generally annular shape and extends upward from the upper surface of the cover body 310. The structure of the attachment portion 320 is well known and is not shown in the drawings. However, the attachment portion 320 has two opposing flanges at two circumferential ends. With the mounting portion 320 positioned so as to surround the mounting portion 22 of the gear housing 20, a bolt is inserted into the 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 mounting portion 22.

[0037] The grinder 10 described above has a mechanical configuration that allows the braking by the braking mechanism 60 to be released only when the side handle 200 is attached to either of the attachment portions 29a, 29b of the gear housing 20. Hereinafter, the mechanical configuration will be described in detail with reference to the drawings.

[0038] As shown in FIG. 1, an operating member 50 is provided below the motor housing 30 and the handle housing 40. The operating member 50 is an elongated member extending in the front-to-rear direction. The operating member 50 has a front end 51, a rear end 52, and two protrusions 53. The front end 51 and the rear end 52 are thinner than the other parts of the operating member 50 and protrude toward the front and rear, respectively.

[0039] As shown in FIG. 7 , the front end 51 is inserted into a through-hole 36 extending in the front-rear direction and formed in the bottom of the motor housing 30, and engages with the motor housing 30 via a concave-convex shape. As shown in FIG. 1 , the rear end 52 is supported by the bottom of the handle housing 40. Specifically, a hole 43 communicating with the interior of the handle housing 40 is formed in the bottom of the handle housing 40. A support portion 44 is formed on the rear side of the hole 43, defining the rear end of the hole 43. The support portion 44 has a larger diameter than the rear side of the handle housing 40, and its radially outer end protrudes toward the front. This forms a step on the radially inner side of the support portion 44. The rear end 52 of the operating member 50 rests on the step of the support portion 44. With this configuration, the operating member 50 is attached to the motor housing 30 and the handle housing 40 in a non-detachable state. As a result, the operating member 50 is configured to be pivotable counterclockwise about the engagement point between the front end portion 51 and the motor housing 30 as a fulcrum from the OFF position shown in FIG. 1 to the ON position shown in FIG.

[0040] As shown in Fig. 1, the two protrusions 53 extend upward from the top of the operating member 50 and are spaced apart in the left-right direction (only the left protrusion 53 is visible in Fig. 1). The protrusions 53 are located at positions corresponding to the holes 43 in the front-rear direction.

[0041] As shown in Fig. 1, an unlocking member 54 is attached to the operating member 50. The unlocking member 54 is provided at approximately the center of the operating member 50 in the front-to-rear direction. The unlocking member 54 is provided to switch the status of the operating member 50 between an unlocked state (see Fig. 1) in which displacement of the operating member 50 from the OFF position to the ON position is prevented, and an unlocked state (see Fig. 10) in which displacement of the operating member 50 from the OFF position to the ON position is permitted, by changing the state of engagement with the operating member 50.

[0042] Specifically, the lock-off member 54 is supported by the operating member 50 via a pin 57 supported in a boss provided inside the operating member 50. The lock-off member 54 is pivotable about the pin 57 between the locked-off position shown in Fig. 1 and the unlocked position shown in Fig. 10. The lock-off member 54 is constantly biased toward the locked-off position shown in Fig. 1 by a torsion spring (not shown).

[0043] The lock-off member 54 has an abutment end 55 and an operating end 56. When the lock-off member 54 is in the unlocked position, the lock-off member 54 protrudes downward through a hole 58 in the lock-off member 54. The abutment end 55 abuts against an abutment portion 37 provided at the rear end and bottom of the motor housing 30, protruding downward from the motor housing 30. Therefore, even if a user presses the operating member 50 upward to move the operating member 50 from the OFF position (see FIG. 1) to the ON position (see FIG. 10) (hereinafter also referred to as an ON operation), the pivoting of the operating member 50 is prevented. This maintains the unlocked state of the operating member 50. On the other hand, when a user pulls the operating end 56 rearward with their finger, the lock-off member 54 pivots counterclockwise against the biasing force of the torsion spring. As a result, the lock-off member 54 is housed in the hole 58 in the operating member 50, as shown in FIG. 10. That is, the lock-off member 54 is retracted to a position where it does not abut against the abutment portion 37. As a result, the user can pivot the operating member 50 to the ON position shown in FIG.

[0044] As shown in FIG. 1, a link member 45 is disposed above the operating member 50. The link member 45 has a through-hole 49 that penetrates in the left-right direction. A pin (not shown) supported by a boss formed inside the motor housing 30 is inserted into this through-hole 49. This allows the link member 45 to pivot around the pin. The link member 45 is biased in the counterclockwise direction by a torsion spring (not shown).

[0045] The link member 45 includes three arms 46, 47, and 48 extending radially outward relative to the pivot axis of the link member 45. The first arm 46 is located at the uppermost position, the third arm 48 is located at the lowermost position, and the second arm 47 is located midway between the first arm 46 and the third arm 48. The first arm 46 of the link member 45, which is biased counterclockwise, abuts against the abutment surface 38 of the motor housing 30, thereby defining an initial pivot position of the link member 45. When the first arm 46 is pivoted clockwise from the initial position shown in FIG. 1 against the biasing force of the torsion spring, the first arm 46 is positioned so that it can press the input member 42 of the switch 41 rearward, thereby switching the switch 41 from an OFF state to an ON state, as shown in FIG. 10 .

[0046] The second arm 47 is positioned so as to overlap the two protrusions 53 of the operating member 50 when viewed in the vertical direction. The tip of the second arm 47 is located directly above the protrusions 53. When the user presses the operating member 50 upward, displacing the operating member 50 from the OFF position shown in FIG. 1 to the ON position shown in FIG. 10 , the second arm 47 is lifted upward by the protrusions 53, as shown in FIG. 10 . This causes the link member 45 to pivot clockwise against the biasing force of the torsion spring, and as described above, the first arm 46 switches the switch 41 to the ON state. On the other hand, when the user releases the force pressing the operating member 50 upward, the link member 45 returns to the initial position shown in FIG. 1 due to the biasing force of the torsion spring, and the operating member 50 also returns to the OFF position shown in FIG. 1 . This returns the switch 41 to the OFF state. In this way, the link member 45 is configured to operate in conjunction with the displacement of the operating member 50 between the OFF position and the ON position.

[0047] As shown in Figure 1, the third arm 48 has a generally L-shaped tip bent forward. The rear end of a brake release member 66 is placed on the tip of the third arm 48. The brake release member 66 is an elongated member that extends in the front-rear direction along the bottom of the motor housing 30. The brake release member 66 extends from the third arm 48, passing through a baffle plate 39 (see Figure 7) located in front of the electric motor 31, to a position immediately behind the brake member 63.

[0048] When the operating member 50 is displaced from the OFF position shown in FIG. 1 to the ON position shown in FIG. 10 by a user operation, the link member 45 pivots clockwise as described above. At this time, the third arm 48 presses the brake release member 66 forward. As a result, the brake release member 66 displaces forward as shown in FIGS. 10 and 13 and presses the disk 63a of the brake member 63 forward. As a result, the braking by the braking mechanism 60 is released as described above. The link member 45 and the brake release member 66 are configured so that the brake release by the third arm 48 and the brake release member 66 occurs before the first arm 46 switches the switch 41 to the ON state. By linking the operating member 50 and the brake release member 66 as in this embodiment, a configuration can be easily realized in which the brake state is reliably released before the switch 41 is turned ON. In particular, in this embodiment, the operating member 50 and the brake release member 66 are linked via the link member 45, and therefore, by appropriately setting the circumferential positions of the arms 46, 47, 48 on the link member 45, it is possible to easily realize a configuration in which the brake state is reliably released before the switch 41 is turned on. When the user releases the force pressing the operating member 50 upward, the biasing force of the biasing member 65 returns the brake release member 66 to its initial position (see FIGS. 1 and 7) in which it does not press the brake member 63 forward.

[0049] When the side handle 200 is not attached to either of the attachment portions 29a, 29b, the grinder 10 has the function of preventing the brake release member 66 from moving forward as described above (moving forward to release the brake applied by the brake mechanism 60). This function is achieved by a single regulating member 70 (see FIG. 8) and two intermediate members 80 (see FIG. 9). The directions shown in FIGS. 8 and 9 indicate the directions when the regulating member 70 and the intermediate members 80 are assembled into the grinder 10. The two intermediate members 80 are arranged symmetrically with respect to the rotation axis AX1, as will be described later, and FIG. 9 shows the direction of the right-side intermediate member 80.

[0050] First, the intermediate member 80 will be described. As shown in FIG. 9, the intermediate member 80 has a pressing portion 81 that extends in a direction perpendicular to the up-down direction, and a pressed portion 82. A groove 83 is formed on the upper surface of the pressing portion 81. The groove 83 has two grooves, one on the upper side and the other on the side farther from the rotation axis AX1 (see FIG. 9). 9 1, the intermediate member 80 disposed on the right side of the rotation axis AX1 is formed so as to be open to the right side. The pressed portion 82 extends downward from approximately the center of the pressing portion 81 in the left-right direction. A through hole 84 is formed in the pressing portion 81 on the side farther from the rotation axis AX1 than the pressed portion 82. The through hole 84 extends in the front-rear direction.

[0051] 3, each intermediate member 80 is attached to the gear housing 20 by a press-fit pin 85 that passes through a through-hole 84 from the rear side and extends into the gear housing 20. A slight clearance is secured in the front-to-rear direction between the intermediate member 80 and the head of the press-fit pin 85 so that the intermediate member 80 can pivot about the press-fit pin 85.

[0052] As shown in FIG. 5, each of the intermediate members 80 is biased by a leaf spring 86 serving as a biasing member. Specifically, the leaf spring 86 has a generally L-shaped bent shape, with one side of the bent portion housed in a hole 20a formed in the gear housing 20. The other side of the bent portion is housed in a groove 83 of the intermediate member 80. As a result, the intermediate member 80 is constantly biased toward an initial position (see FIG. 5) where the pressed portion 82 abuts against the stopper 20b. As shown in FIGS. 2 and 5, the stopper 20b is a portion that protrudes inward from the inner surface of the gear housing 20 and also forms the mounting portions 29a, 29b. As shown in FIG. 2, the two intermediate members 80 are arranged so that their pressed portions 82 respectively block the vicinity of the inner ends of the mounting portions 29a, 29b of the gear housing 20.

[0053] When the side handle 200 is attached to either of the attachment portions 29a, 29b, the intermediate member 80 is pressed by the pressing portion 220 of the side handle 200 and pivoted. For example, when the side handle 200 is attached to the second attachment portion 29b of the attachment portions 29a, 29b, as shown in Fig. 11, the right-side intermediate member 80 pivots in a direction in which the pressed portion 82 moves away from the stopper 20b against the biasing force of the leaf spring 86. Although not shown in the figures, when the side handle 200 is attached to the attachment portion 29a, the left-side intermediate member 80 pivots in a direction in which it resists the biasing force of the leaf spring 86.

[0054] Next, the regulating member 70 will be described. As shown in FIG. 8, the regulating member 70 includes a main body 71, two pressed portions 73, and one regulating portion 75. The main body 71 has an annular shape that is open at the top. The pressed portions 73 are portions that protrude forward from both ends (upper ends) of the main body 71. A groove 74 is formed on the upper surface of the pressed portion 73. The groove 74 is open at the top and front. The regulating portion 75 is a portion that protrudes rearward from the main body 71 at the bottom (the center of the open annular shape) of the main body 71. Two through holes 72 that penetrate the main body 71 in the front-rear direction are formed approximately at the center of the main body 71 in the up-down direction. The through holes 72 are elongated holes with the up-down direction as the longitudinal direction.

[0055] As shown in Fig. 6, the restricting member 70 is disposed so as to surround the motor shaft 32 in the circumferential direction. As shown in Figs. 3 and 6, the restricting member 70 is attached to the bearing support 34 by two screws 76 that pass through the two through holes 72 and screw into threaded holes in the bearing support 34. A slight clearance is formed in the front-to-rear direction between the heads of the screws 76 and the bearing support 34, and the through holes 72 are elongated holes, so the restricting member 70 is supported by the bearing support 34 via the screws 76 so as to be displaceable along the through holes 72.

[0056] As shown in Fig. 5, the pressed portion 73 of the regulating member 70 is above the intermediate member 80 and is close to the pressing portion 81 of the intermediate member 80. As shown in Fig. 5, when the side handle 200 is not attached, the pressed portion 73 and the pressing portion 81 are slightly spaced apart in the vertical direction. Also, as shown in Fig. 4, the front portion of the pressed portion 73 overlaps the rear portion of the pressing portion 81 when viewed in the vertical direction.

[0057] Furthermore, as shown in FIGS. 4 and 6, a biasing member 77 is disposed in a compressed state between the pressed portion 73 and the gear housing 20. In this embodiment, the biasing member 77 is in the form of a coil spring. As shown in FIG. 4, the biasing member 77 is located in the groove 74. The outer edge of the pressed portion 73, which forms the groove 74, restricts the movement of the biasing member 77. The biasing member 77 biases the pressed portion 73 downward. The biasing forces of the two biasing members 77 are equal, and as shown in FIG. 6, when the side handle 200 is not attached, the two pressed portions 73 are located at the same vertical position.

[0058] Furthermore, as shown in FIGS. 1 and 7 , when the side handle 200 is in the unattached state, the restricting portion 75 of the restricting member 70 is in front of and close to the brake member 63 (more specifically, the outer protrusion 63c) of the brake mechanism 60. In other words, the restricting portion 75 is located on the displacement path of the outer protrusion 63c when the brake member 63 is displaced from the braking position shown in FIG. 7 to the non-braking position shown in FIG. 13 . Therefore, even if the brake release member 66 presses the outer protrusion 63c forward as a result of the user performing the on operation of the operating member 50 as described above, the outer protrusion 63c abuts against the restricting portion 75, restricting further displacement of the outer protrusion 63c. As a result, the brake mechanism 60 is prevented from being released from the braked state. In other words, the restricting portion 75 prevents the brake mechanism 60 from releasing the braked state by abutment between the members (here, abutment between the restricting portion 75 and the outer protrusion 63c). The position of the restricting member 70 at this time is also called the blocking position.

[0059] On the other hand, when the side handle 200 is attached to either of the attachment portions 29a, 29b, the brake mechanism 60 is allowed to release the braked state. Specifically, when the side handle 200 is attached to either of the attachment portions 29a, 29b, the restricting member 70 is indirectly (in other words, Intermediate member 80 11 and 12, the restricting member 70 is displaced so as to tilt in the left-right direction. For example, when the side handle 200 is attached to the second attachment portion 29b of the attachment portions 29a, 29b, the right-side intermediate member 80 pivots as described above and pushes up the right-side pressed portion 73 against the biasing force of the right-side biasing member 77. This causes the restricting member 70 to be displaced so as to tilt in the left-right direction, so that the right-side pressed portion 73 is positioned higher than the left-side pressed portion 73.

[0060] At this time, as shown in FIG. 12, the restricting portion 75 also displaces toward the upper right. As a result, the restricting portion 75 deviates from the displacement path of the outer protrusion 63c when the brake member 63 displaces from the braking position shown in FIG. 7 to the non-braking position shown in FIG. 13. As a result, as shown in FIG. 13, when the user performs the on operation of the operating member 50 as described above and the brake release member 66 presses the outer protrusion 63c forward, the outer protrusion 63c can displace forward without coming into contact with the restricting portion 75 (i.e., without the aforementioned inter-member contact occurring). Therefore, the release of the braking state of the brake mechanism 60 is permitted. The position of the restricting member 70 at this time is also referred to as the permitted position.

[0061] Although not shown, when the side handle 200 is attached to the attachment portion 29a, the left intermediate member 80 pivots as described above and pushes up the left pressed portion 73 against the biasing force of the left biasing member 77. This causes the regulating member 70 to be inclined and displaced so that the left pressed portion 73 is positioned higher than the right pressed portion 73. In other words, when the side handle 200 is attached to the attachment portion 29a, the regulating member 70 is displaced in the direction opposite to the direction of displacement when the side handle 200 is attached to the attachment portion 29b. In this case, too, the regulating portion 75 deviates from the displacement path of the outer protrusion 63c when the brake member 63 is displaced from the braking position shown in FIG. 7 to the non-braking position shown in FIG. 13. This allows the braking mechanism 60 to be released from the braking state.

[0062] When the side handle 200 is removed from the attachment portion 29a or the attachment portion 29b, the restricting portion 75 is returned to the blocking position shown in FIGS.

[0063] According to the grinder 10 described above, when the side handle 200 is not attached to either of the attachment portions 29a, 29b, the restricting member 70 is in a blocking position where the restricting portion 75 prevents the brake mechanism 60 from releasing the braked state by abutting against the restricting portion 75. On the other hand, when the side handle 200 is attached to either of the attachment portions 29a, 29b, the restricting member 70 is displaced to a permitting position where the restricting portion 75 permits the brake mechanism 60 to release the braked state. Therefore, a configuration in which the tool bit 28 can be driven only when the side handle 200 is attached can be realized using only a mechanical structure without using a sensor. Moreover, when the side handle 200 is not attached, the tool bit 28 is forced to stop by the brake mechanism 60 (a state in which the drive of the tool bit 28 is stopped regardless of the on / off state of the switch 41). Therefore, compared to a configuration in which the ON operation of the operating member 50 is simply prevented, the driving of the tool bit 28 can be more reliably restricted when the side handle 200 is not attached.

[0064] Furthermore, according to the grinder 10, a single regulating member 70 is shared by the two mounting portions 29a, 29b, thereby reducing the number of parts and simplifying the device structure. The regulating member 70 has an annular shape corresponding to the arrangement of the mounting portions 29a, 29b, which are spaced apart in the circumferential direction about the rotation axis AX1. This allows the single regulating member 70 to be shared by the mounting portions 29a, 29b with a simple configuration. Moreover, because the regulating member 70 is indirectly pressed by the side handle 200 via the intermediate member 80, the regulating member 70 can be made smaller than in a configuration in which the regulating member 70 is directly pressed by the side handle 200 (in other words, a configuration in which the regulating member 70 is large enough to reach a position where it is directly pressed by the side handle 200). Therefore, space constraints are less likely to be a factor in designing the internal layout of the device.

[0065] Furthermore, according to the grinder 10, the brake mechanism 60 is disposed around the motor shaft 32, not around the spindle 25. This allows the area around the spindle 25 (i.e., the gear housing 20 and its internal structure) to be made smaller and lighter. In other words, the gear housing 20, which is located relatively far from the handle housing 40 held by the user, can be made smaller and lighter. This improves the ease of handling of the grinder 10. Moreover, because the distance between the brake mechanism 60 and the operating member 50, which interlocks with the brake release member 66 of the brake mechanism 60, is shortened, the mechanical structure for interlocking the brake release member 66 and the operating member 50 can be simplified.

[0066] Furthermore, with grinder 10, the direction of displacement of regulating member 70 is opposite when side handle 200 is attached to mounting portion 29a and when side handle 200 is attached to mounting portion 29b. Therefore, when side handle 200 is attached to either mounting portion 29a or 29b, a configuration in which regulating member 70 is pressed against side handle 200 to allow the release operation of the braking state by braking mechanism 60 can be realized with a simple device structure.

[0067] A second embodiment of the present invention will be described below with reference to Figures 14 to 20. Only the differences between the second embodiment and the first embodiment will be described below. Components that are the same as or similar to those in the first embodiment are given the same reference numerals, and their description will be omitted. As shown in Figure 14, a grinder 410 according to the second embodiment includes an operating member 450 instead of the operating member 50, a lock-off unit 443 instead of the lock-off member 54, a pivot member 455 instead of the link member 45, and a braking mechanism 460 instead of the braking mechanism 60.

[0068] As shown in FIG. 14 , 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 the front end portion of the operating member 450 and has a smaller thickness (width in the up-down direction) than the other portions. The action end 451 passes through a through-hole 431 (see FIG. 17 ) formed in the motor housing 430 and reaches the interior 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 that protrudes rearward from 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.

[0069] This operating member 450 can pivot up and down around 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. 14, which is its initial position, to the ON position shown in Fig. 16, the switch 41 is switched from the OFF state to the ON state via the pivot member 455.

[0070] Specifically, the pivot member 455 is disposed above the protrusion 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 arm 456 and a second arm 457 extending radially outward with respect to the pivot axis of the pivot member 455. The first arm 456 is disposed directly above the protrusion 453, and the second arm 457 is disposed higher than the first arm 456. Although not shown in the figure, the pivot member 455 is biased counterclockwise by a biasing member (for example, a torsion spring) so that the first arm 456 abuts against the protrusion 453 of the operating member 450.

[0071] In an unlocked state (to be described later), when the user presses the operating member 450 upward, the operating member 450 is pivoted upward. This causes the protrusion 453 to displace the first arm 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 arm 457 is also pivoted clockwise together with the operating member 450. When the operating member 450 pivots to the ON position shown in FIG. 16 , the input member 42 of the switch 41 is pressed by the second arm 457 and pushed into the switch 41. This switches the switch 41 from the OFF state to the ON state. When the user releases the upward pressing of the operating member 450, the biasing force of the biasing member biasing the pivot member 455 causes the operating member 450 to pivot downward, returning to the OFF position shown in FIG. 14 . 14 due to the biasing force of the biasing member, and the input member 42 also retracts from the switch 41. This causes the switch 41 to return from the on state to the off state.

[0072] The lock-off portion 443 has the same function as the lock-off member 54 of the first embodiment. In contrast to the lock-off member 54 of the first embodiment, which is displaceable by itself, the lock-off portion 443 has a fixed (i.e., non-displaceable) engagement structure. In this embodiment, the lock-off portion 443 is formed rearward of the operating member 450 as part of the handle housing 440 (more specifically, the rear and lower part).

[0073] As shown in FIG. 14 , 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.

[0074] 14, the operating member 450 is held in a locked state so as to be displaceable in the front-rear and up-down directions, with the working end 451 inserted into the through-hole 431 and the engaging portion 452 placed on the support portion 446. The operating member 450 is manually displaced in the front-rear and up-down directions by the user. The user can easily displace the operating member 450 in the front-rear and up-down directions by hooking their finger on the protrusion 454.

[0075] 17 and 19, braking mechanism 460 includes a brake member 463 instead of brake member 63, and a brake release member 466 instead of brake release member 66. Brake member 463 includes a radially extending disk 463a and an inner protrusion 63b, but does not include an outer protrusion 63c. A notch 463d that is open on the bottom side is formed at the bottom end of disk 463a.

[0076] As shown in FIGS. 14, 17, and 19, the brake release member 466 is disposed between the restricting portion 75 of the restricting member 70 and the operating member 450 in a manner displaceable in the front-rear direction. As shown in FIGS. 17 and 19, in this embodiment, the brake release member 466 is a plate-shaped member extending in the front-rear direction. A flange portion 467 having a larger vertical and lateral width than the other portions is formed at the rear end of the brake release member 466. As shown in FIG. 19, a pressing portion 468 having a larger lateral width than the other portions is formed at the front side of the brake release member 466. A portion of the brake release member 466 forward of the pressing portion 468 is formed as an elongated tip portion 469. As shown in FIGS. 17 and 19, the tip portion 469 passes through the notch 463d of the brake member 463 and extends to just before the restricting portion 75 of the restricting member 70.

[0077] As shown in FIG. 17 , a coil spring 465 serving as a biasing member is disposed around the brake release member 466. The coil spring 465 is held in a compressed state between the baffle plate 39 fitted inside the motor housing 430 and a flange portion 467. The coil spring 465 constantly biases the brake release member 466 rearward, that is, toward the operating member 450. Therefore, the flange portion 467 always abuts against the working end 451 of the operating member 450 in the front-rear direction, regardless of the position of the brake release member 466 in the front-rear direction. When the user displaces the operating member 450 forward, the brake release member 466 is pushed forward by the operating member 450 against the biasing force of the coil spring 465 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 brake release member 466 are returned to their original positions by the biasing force of the coil spring 465. In this way, the brake release member 466 is configured to move in conjunction with the displacement of the operating member 450 in the front-rear direction.

[0078] The operation of such grinder 410 will be described below. First, as shown in FIG. 14, when operating member 450 is in the OFF position and in a locked-off state, engaging portion 452 of operating member 450 is housed in a recess between engaging portion 445 of lock-off portion 443 and support portion 446. The position of operating member 450 at this time is also referred to as the locked-off position. When operating member 450 is in the locked-off position, engaging portion 445 is located directly above engaging portion 452. Therefore, even if a user attempts to press operating member 450 upward, engaging portion 452 abuts on engaging portion 445, restricting upward displacement of operating member 450. Therefore, operating member 450 is prevented from displacing from the OFF position (see FIG. 14) to the ON position (see FIG. 16).

[0079] When the operating member 450 is in the OFF position and in the locked-off state, the brake release member 466 is not pressed forward by the operating member 450 and is located in the position shown in Figures 14, 17, and 19. At this time, as shown in Figure 19, the pressing portion 468 of the brake release member 466 and the disc 463a of the brake member 463 are spaced apart in the front-to-rear direction. Also, as shown in Figures 14, 17, and 19, the brake member 463 and the brake shoe 64 are in a braking position where they press the brake plate 62.

[0080] To change the operating member 450 from the unlocked state to the unlocked state, the user needs to displace the operating member 450 forward. However, as shown in FIGS. 17 and 19 , when the side handle is not attached, the restricting portion 75 of the restricting member 70 is located in front of the tip 469 of the brake release member 466. Therefore, when the user attempts to displace the operating member 450 forward, the tip 469 of the brake release member 466, which is linked to the operating member 450, abuts against the restricting portion 75, thereby restricting the forward displacement of the brake release member 466 (and thus the operating member 450). In this way, the restricting portion 75 prevents the status of the operating member 450 from being switched from the unlocked position state to the unlocked state due to inter-member abutment (here, abutment between the restricting portion 75 and the tip 469 of the brake release member 466). In other words, the restricting portion 75 blocks the displacement path along which the brake releasing member 466 is displaced forward.

[0081] On the other hand, in a state where the side handle 200 is attached to either of the attachment portions 29a, 29b (see the first embodiment), the restricting member 70 is displaced in the same manner as in the first embodiment, and as shown in FIGS. 18 and 20, the restricting member 70 does not block the displacement path along which the brake release member 466 is displaced forward. In other words, the above-described inter-member abutment does not occur, and the operating member 450 and the brake release member 466 are allowed to displace forward. Therefore, the user can displace the operating member 450 and the brake release member 466 forward to the positions shown in FIGS. 15, 18, and 20 against the biasing force of the coil spring 465.

[0082] 15, the engaging portion 452 of the operating member 450 is supported on the support portion 446 of the lock-off portion 443, but there is no engaging portion 445 directly above the engaging portion 452. Therefore, the operating member 450 is in a state where it can be displaced upward (i.e., the lock-off released state). The position of the operating member 450 at this time is also called the lock-off released position.

[0083] When the brake release member 466 is displaced forward as the operating member 50 is displaced from the lock-off position to the lock-off release position, the pressing portion 468 of the brake release member 466 comes into contact with the disc 463a of the brake member 463 and presses it forward, as shown in Fig. 20. This causes the brake member 463 and the brake shoe 64 to displace forward to a position where the brake shoe 64 is separated from the braked portion 62b of the brake plate 62 in the front-to-rear direction (i.e., the brake release position), as shown in Fig. 18. In this way, the braking state by the braking mechanism 460 is released.

[0084] After the operating member 450 is in the OFF position and in the unlocked state in this manner, when the user displaces the operating member 450 upward, the switch 41 is turned ON via the pivot member 455 in the manner described above, as shown in FIG. 16 . On the other hand, when the user wants to stop driving the grinder 410, the operating member 450 returns from the ON position (see FIG. 16 ) to the OFF position (see FIG. 14 ) as described above when the user releases the upward displacement of the operating member 450. At this time, the operating member 450 returns from the unlocked position (see FIG. 15 ) to the unlocked position (see FIG. 14 ) due to the biasing force of the coil spring 465, and the brake release member 466 returns from the position shown in FIGS. 18 and 20 to the position shown in FIGS. 17 and 19 . Accordingly, the brake member 463 and the brake shoe 64 also return from the non-braking position to the braking position. As is clear from the above description, in this embodiment, the operation member 450 and the brake release member 466 are linked together to provide a configuration in which the operation to release the lock-off state by the operation member 450 also serves as an operation to release the braked state by the brake mechanism 460.

[0085] According to the grinder 410 described above, similar to the first embodiment, a configuration in which the tool bit 28 can be driven only when the side handle 200 is attached can be realized using only a mechanical structure without using a sensor. Also, similar to the first embodiment, when the side handle 200 is not attached, the tool bit 28 is forced to stop by the braking mechanism 460. Therefore, compared to a configuration in which the on operation of the operating member 450 is simply prevented, the driving of the tool bit 28 can be more reliably restricted when the side handle 200 is not attached.

[0086] Furthermore, since the displacement of the operating member 450 accompanying the above-described unlocking operation is easy for the user to identify, if the electric motor 31 cannot be driven despite the operation of displacing the operating member 450 from the OFF position to the ON position, the user will easily realize that the reason is not a malfunction of the switch 41, but that the unlocking operation cannot be performed because the side handle 200 is not attached.

[0087] Furthermore, with the grinder 410, if the user displaces the operating member 450 forward to switch the status of the operating member 450 from the lock-off state to the lock-off release state, the brake release member 466 will release the braked state even if the operating member 450 remains in the OFF position. Therefore, it is possible to easily realize a configuration that reliably releases the braked state before the switch 41 is turned ON.

[0088] Although the embodiments of the present invention have been described above, the above-described embodiments are intended to facilitate understanding of the present invention and are not intended to 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. Furthermore, any combination or omission of the elements described in the claims and specification is possible within the scope of solving at least part of the above-described problems or achieving at least part of the effects.

[0089] For example, the shapes and configurations of the components of grinder 10 described above are merely examples, and any changes are possible as long as the functions of the components are maintained. For example, when side handle 200 is attached to either mounting portion 29a or 29b, restricting member 70 may have a size and shape that allows it to be directly pressed and displaced by side handle 200 without intermediate member 80 being used.

[0090] Furthermore, the restricting member 70 may have a shape that rotates about a rotation axis parallel to the rotation axis AX1 when pressed directly or indirectly by the side handle 200, instead of being tilted. In this case, the through hole 72 of the restricting member 70 may be formed in an arc shape so as to guide the rotational displacement of the restricting member 70. The rotation direction of the restricting member 70 may be the same when the side handle 200 is attached to the attachment portion 29a and when the side handle 200 is attached to the attachment portion 29b, or may be different.

[0091] Furthermore, the braking mechanism 60 or 460 may be arranged around the spindle 25 and configured to brake the rotation of the spindle 25. In this case, a conversion mechanism may additionally be provided that converts the displacement direction of the brake release member 66 or 466 into the displacement direction of the brake member 63 or 463 and the brake shoe 64.

[0092] Furthermore, in the second embodiment, a displaceable lock-off member may be provided as the lock-off portion instead of the lock-off portion 443, which is a fixed engagement structure. In this case, the brake release member may be configured to perform a brake release operation in conjunction with the displacement of the lock-off member from the lock-off position to the lock-off release position.

[0093] Furthermore, the grinder 10 or 410 may be configured so that displacement of the brake release member 66 or 466 for releasing the brake is prevented when the cover 300, instead of the side handle 200, is not attached. In this case, a restricting member that is pressed directly or indirectly against the cover 30 may be provided. Alternatively, the grinder 10 or 410 may be configured so that displacement of the brake release member 66 or 466 for releasing the brake is prevented when at least one of the side handle 200 and the cover 300 is not attached. In this case, an additional restricting member that displaces depending on whether the cover 300 is attached or not may be provided. In this case, the additional restricting member may be arranged to be aligned with the restricting member 70 in the front-to-rear direction and, when at least one of the side handle 200 and the cover 300 is not attached, may block the displacement path of the brake release member 66 or 466 for releasing the brake in series with the restricting member 70.

[0094] Furthermore, the above-described embodiment is not limited to grinders, but can be applied to any power tool to which an accessory can be detachably attached.

[0095] The correspondence between the components of the above embodiment and the components of the present invention is shown below. However, the components of the embodiment are merely examples and do not limit the components of the present invention. The grinder 10, 410 is an example of a "power tool." The tool tip 28 is an example of a "tool tip." The electric motor 31 is an example of a "motor." The braking mechanism 60, 460 is an example of a "braking mechanism." The side handle 200 is an example of an "accessory." The mounting portions 29a, 29b are an example of an "mounting portion." The restricting member 70 is an example of a "restricting member." The intermediate member 80 is an example of an "intermediate member." The motor shaft 32 is an example of a "motor shaft." The spindle 25 is an example of a "final output shaft." The brake plate 62 is an example of a "braked member." The brake members 63, 463 and the brake shoe 64 are examples of a "braking member." The biasing member 65 is an example of a "biasing member." The brake release members 66, 466 are an example of a "brake release member." The operating members 50, 450 are an example of an "operating member." The link member 45 is an example of a "link member." The lock-off portion 443 is an example of a "lock-off portion." [Explanation of symbols]

[0096] 10,410...Grinder 20...Gear housing 20a...hole 20b...Stopper 22...Mounting part 23...Small bevel gear 24...Large bevel gear 25...Spindle 26...Inner flange 27...Lock nut 28... Tip tool 29a...Mounting part 29a...First mounting part 29b...Mounting part 29b...Second mounting part 30,430...Motor housing 31...Electric motor 32...Motor shaft 33...Bearing 34...Bearing support 35...Protrusion 36...Through hole 37...Abutment part 38...Abutment surface 39...Baffle plate 40,440...Handle housing 41...Switch 42...Input member 43...hole 44...Support part 45...Link member 46...Arm 46...First arm 47...Second arm 48...Third Arm 49...Through hole 50,450...Operating member 51...front end 52...Rear end 53...protrusion 54...Lock-off member 55...Abutting end 56...Operation end 57...pin 58...hole 60,460...braking mechanism 61...Brake holder 62...Brake plate 62a...Cylindrical part 62b...braked part 63,463...Brake members 63a,463a...Disc 63b...Inner protrusion 63c...Outer protrusion 64...Brake shoe 65... Urging member 66,466...Brake release member 70...Regulatory components 71...Main body 72...Through hole 73...Pressure receiving part 74...Groove 75...Regulatory Department 76...Screw 77... Urging member 80...Intermediate member 81...Pressing part 82...Pressure receiving part 83...Groove 84...Through hole 85...Press-fit pin 86...Leaf spring 200...Side handle 210...Mounting part 220...Pressing part 300...cover 310...Cover body 320...Mounting part 431...Through hole 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 arm 457...Second Arm 458...pin 463d...notch 465...coil spring 467...Flange part 468...Pressing part 469...Tip AX1, AX2...rotation axis

Claims

1. A power tool, a motor configured to provide a driving force to the tool accessory; a braking mechanism disposed on a drive force transmission path from the motor to the tool bit and configured to brake the drive of the tool bit; at least one mounting portion configured to removably mount an accessory; An intermediate member; Regulatory member and Equipped with The intermediate member is When the accessory is not attached to any of the at least one attachment portions, the accessory is in a position where it does not press the restricting member, When the accessory is attached to any one of the at least one attachment portions, the accessory is pressed and displaced to a position where the restricting member is pressed. It is configured as follows: the restricting member is configured to be pressed by the intermediate member and displaced when the accessory is attached to any one of the at least one attachment portions, The braking mechanism includes: a braked member configured to rotate together with the tool bit; a braking member configured to be pressed against the braked member to achieve a braking state, and disposed displaceably between a braking position in contact with the braked member and a non-braking position separated from the braked member; Equipped with the accessory is a side handle; The regulating member is When the accessory is not attached to any of the at least one attachment portion, the accessory is in a blocking position that mechanically prevents the brake member from moving from the braking position to the non-braking position, thereby preventing the brake mechanism from releasing the braked state; When the accessory is attached to any one of the at least one attachment portions, the regulating member is pressed by the intermediate member and displaced to an allowable position that does not mechanically prevent the brake member from displacing from the braking position to the non-braking position, thereby permitting the release operation of the braked state. Power tools.

2. 2. The power tool of claim 1, The at least one mounting portion comprises a plurality of mounting portions. Power tools.

3. 3. The power tool of claim 2, The restricting member is a single member provided in common to the plurality of mounting portions. Power tools.

4. 4. The power tool of claim 3, the plurality of mounting portions include a first mounting portion and a second mounting portion; the permissible positions include a first permissible position and a second permissible position, The regulating member is When the accessory is attached to the first attachment portion, the accessory is displaced from the blocking position in a first direction to the first permissive position, When the accessory is attached to the second attachment portion, the accessory is displaced from the blocking position in a second direction opposite to the first direction to the second allowing position. It was configured as Power tools.

5. A power tool according to any one of claims 1 to 4, the motor comprises a motor shaft; The power tool further includes a final output shaft configured to transmit the driving force from the motor shaft, the final output shaft being capable of mounting the tool accessory; The braking mechanism is disposed around the motor shaft. Power tools.

6. 6. The power tool of claim 5, The braking mechanism includes: a braked member fixed to the motor shaft and arranged to surround the motor shaft in a circumferential direction; a braking member configured to be pressed against the braked member to achieve the braking state, and disposed displaceably between a braking position in contact with the braked member and a non-braking position spaced apart from the braked member; a biasing member that biases the braking member toward the braking position; a brake release member configured to press and displace the braking member from the braking position toward the non-braking position against the biasing force of the biasing member; Equipped with Power tools.

7. 7. The power tool of claim 6, a switch for driving the motor; an operating member configured to be displaceable between an OFF position that turns the switch OFF and an ON position that turns the switch ON; Furthermore, The brake release member is configured to move in conjunction with the displacement of the operating member between the OFF position and the ON position. Power tools.

8. 8. The power tool of claim 7, a link member configured to move in conjunction with displacement of the operating member between the off position and the on position; The link member is configured to be displaced when the operating member is displaced from the off position to the on position, to press the switch so that the switch is in the on state, and to press the brake release member so that the brake state is released. Power tools.

9. 7. The power tool of claim 6, a switch for driving the motor; an operating member configured to be displaceable between an OFF position that turns the switch OFF and an ON position that turns the switch ON; a lock-off unit configured to switch the status of the operating member between a lock-off state in which displacement of the operating member from the OFF position to the ON position is prevented and a lock-off release 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 Furthermore, The brake release member is configured to be operatively coupled to an operation for switching between the lock-off state and the lock-off release state. Power tools.

10. A power tool, a motor configured to provide a driving force to the tool accessory and having a motor shaft; a final output shaft configured to transmit the driving force from the motor shaft, the final output shaft being capable of mounting the tool bit; a switch for driving the motor; an operating member configured to be displaceable between an OFF position that turns the switch OFF and an ON position that turns the switch ON; a braking mechanism disposed on a drive force transmission path from the motor to the tool bit and configured to brake the drive of the tool bit; at least one mounting portion configured to removably mount an accessory; a restricting member configured to be directly or indirectly pressed against and displaced by the accessory when the accessory is attached to any one of the at least one attachment portions; Equipped with the accessory is a cover for partially covering the tool bit, the braking mechanism is disposed around the motor shaft; The braking mechanism includes: a braked member fixed to the motor shaft and arranged to surround the motor shaft in a circumferential direction; a braking member configured to be pressed against the braked member to achieve a braking state, the braking member being displaceable between a braking position in contact with the braked member and a non-braking position spaced apart from the braked member, and being disposed closer to the tool bit than the braked member; a biasing member that biases the braking member toward the braking position; a brake release member configured to press and displace the braking member from the braking position toward the non-braking position against the biasing force of the biasing member; Equipped with the brake release member is configured to move in conjunction with displacement of the operating member between the OFF position and the ON position, The regulating member is When the accessory is not attached to any of the at least one attachment portions, the regulating member abuts against the braking member on a side closer to the tool bit than the braking member, thereby being positioned at a blocking position that blocks the braking mechanism from releasing the braked state, When the accessory is attached to any one of the at least one attachment portions, the restricting member is directly or indirectly pressed against the accessory and displaced, thereby being positioned at an allowable position that allows the release operation of the braking state without contacting the braking member. Power tools.

11. 11. The power tool of claim 10, The restricting member and the biasing member partially overlap each other when viewed in a radial direction relative to the motor shaft. Power tools.

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