power tools

Abstract

To provide an electric tool having a new structure in which a power distribution to a motor is permitted only in a state where two kinds of accessories are attached thereto, which is improved in degree of freedom of design of the electric tool.SOLUTION: An electric tool comprises: a motor; a first intermediate member configured to be displaced when a first accessory is attached to a first attachment part; a second intermediate member 70 configured to be displaced when a second accessory 300 is attached to a second attachment part 22; and a first interlocking member 80. The first interlocking member mechanically interlocks with respective displacement of the first intermediate member and the second intermediate member. The first interlocking member is displaced in the same direction when the first accessory is attached thereto and when the second accessory is attached thereto, and is cumulatively displaced when the first accessory and the second accessory are attached thereto. The electric tool is configured so that a power distribution to the motor is permitted only in a state where the first interlocking member is cumulatively displaced.SELECTED DRAWING: Figure 10

Description

Technical Field

[0005] , , ,

[0001] The present invention relates to a power tool configured to removably attach accessories.

Background Art

[0002] Various accessories may be removably attached to power tools. For example, in a grinder having a tip tool configured to be rotationally driven, two types of removable accessories (a side handle and a cover) are provided. The side handle is attached for the user to hold with the other hand when holding the handle of the grinder with one hand. The cover is attached to partially cover the tip tool.

[0003] In such a grinder, there is a desire to prevent the grinder from being used without the accessories attached. For example, Patent Document 1 below discloses a grinder including a first link member that is displaced when a side handle is attached, a first sensor that detects the displacement of the first link member, a second link member that is displaced when a cover is attached, a second sensor that detects the displacement of the second link member, and a controller. The controller allows power to be supplied to the motor (in other words, rotation of the tip tool) only when it is detected by the first sensor and the second sensor that both the side handle and the cover are attached.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the grinder described in Patent Document 1 has two sensors arranged discretely, which can lead to an increase in the size of the device. Specifically, if there are not two available spaces within the housing to discretely arrange the two sensors, the housing needs to be enlarged to secure space for the sensors. For this reason, the technology of the grinder described in Patent Document 1 cannot be widely applied to various grinder designs. This problem is not limited to grinders, but is common to various power tools in which power is only allowed to be supplied to the motor when two types of accessories are attached. For this reason, it is hoped that a power tool with a novel structure that allows power to be supplied to the motor only when two types of accessories are attached will be provided, thereby increasing the design freedom of power tools. [Means for solving the problem]

[0006] This specification discloses a power tool. The power tool may include a motor, a first mounting section for detachably attaching a first accessory, a second mounting section for detachably attaching a second accessory of a different type from the first accessory, a first intermediate member configured to be directly or indirectly pressed and displaced against the first accessory when the first accessory is attached to the first mounting section, a second intermediate member configured to be directly or indirectly pressed and displaced against the second accessory when the second accessory is attached to the second mounting section, and a first interlocking member. The first interlocking member may be configured to be mechanically interlocked with the displacement of the first intermediate member and the second intermediate member, respectively. The first interlocking member may further be configured to be displaced in the same direction when the first accessory is attached to the first mounting section and when the second accessory is attached to the second mounting section, and to be displaced cumulatively when the first accessory and the second accessory are attached to the first mounting section and the second mounting section, respectively. The power tool may be configured such that power is supplied to the motor only when the first interlocking member has been cumulatively displaced.

[0007] This power tool provides a novel structure in which the first and second accessories are attached to the first and second mounting parts, respectively, thereby allowing power to be supplied to the motor only when the first interlocking member is cumulatively displaced in conjunction with the first and second intermediate members. Therefore, it is possible to increase the design freedom of power tools that have a structure in which power to the motor is only allowed when both types of accessories are attached. For example, the first intermediate member, the second intermediate member, and the first interlocking member can be compactly arranged in the available space within the housing. Also, since the first interlocking member is interlocked with both the first and second intermediate members (in other words, the first interlocking member is shared by the first and second intermediate members), a configuration that allows power to be supplied to the motor only when both the first and second accessories are attached can be efficiently realized. For example, in an embodiment in which a power tool is equipped with a sensor that detects the cumulative displacement of a first interlocking member, a single sensor can detect that both the first and second accessories are attached. [Brief explanation of the drawing]

[0008] [Figure 1] This is a longitudinal cross-sectional view of a grinder according to one embodiment, showing the tip tool and the side handle and cover, which are accessories, removed. [Figure 2] This is a cross-sectional view of a grinder, showing it with the tip tool and accessories, such as the side handle and cover, removed. [Figure 3] This is a magnified section of Figure 1. [Figure 4] This is a magnified section of Figure 1. [Figure 5] This is a magnified view of a portion of Figure 2. [Figure 6] This is a side view showing an assembly comprising a first intermediate member, a second intermediate member, a first interlocking member, and a second interlocking member, with each member in its initial position. [Figure 7] Figure 6 is a perspective view of the assembly shown. [Figure 8]This is a front view showing the internal structure of the grinder, with each component of the assembly shown in Figure 6 in its initial position. [Figure 9] This is a perspective view showing the internal structure of the grinder, with each component of the assembly shown in Figure 6 in its initial position. [Figure 10] This is a vertical cross-sectional view of the grinder corresponding to Figure 1, showing the attachment of the cutting tool, as well as the side handle and cover as accessories. [Figure 11] This is a cross-sectional view of the grinder corresponding to Figure 2, showing the attachment of the cutting tool, as well as the side handle and cover as accessories. [Figure 12] This is a magnified view of a portion of Figure 10. [Figure 13] This is a magnified view of a portion of Figure 10. [Figure 14] This is a magnified view of a section of Figure 11. [Figure 15] This is a side view showing the assembly with only the side grips attached. [Figure 16] Figure 15 is a perspective view of the assembly shown. [Figure 17] This is a side view showing the assembly with only the cover attached. [Figure 18] Figure 17 is a perspective view of the assembly shown. [Figure 19] This is a side view showing the assembly with both the side grip and cover attached. [Figure 20] Figure 19 is a perspective view of the assembly shown. [Modes for carrying out the invention]

[0009] In one or more embodiments, the power tool may include a sensor configured to directly or indirectly detect the cumulative displacement of the first linkage member, and a controller configured to control the energization of the motor and to permit the energization of the motor only when the cumulative displacement of the first linkage member is detected by the sensor. According to this configuration, it is possible to detect with a single sensor that both the first accessory and the second accessory are attached. Therefore, the design freedom of the power tool can be improved. Also, compared to the case where two sensors are individually installed for each of the first accessory and the second accessory, the number of sensors, i.e., electronic components, and thus the wiring work can be reduced, facilitating manufacturing.

[0010] In one or more embodiments, the power tool may include a second linkage member configured to mechanically interlock with the cumulative displacement of the first linkage member. The first intermediate member, the second intermediate member, and the first linkage member may be arranged on the first side with respect to the motor in the axial direction, which is the direction in which the rotation axis of the motor extends. The sensor and the controller may be arranged on the second side opposite to the first side with respect to the motor in the axial direction. The second linkage member may extend from the first side to the second side. The sensor may be configured to detect the cumulative displacement of the first linkage member based on the displacement of the second linkage member. According to this configuration, since the sensor and the controller, i.e., the electronic components, are arranged on the second side, it is not necessary to make the first side an insulating specification. For this reason, the power tool can be made compact. Also, since it is not necessary to arrange the wiring for electrically connecting the sensor and the controller so as to cross the motor, the length of the wiring can be shortened and the ease of wiring is also improved.

[0011] In one or more embodiments, the first attachment direction for attaching the first accessory to the first attachment portion and the second attachment direction for attaching the second accessory to the second attachment portion may be different from each other. The first intermediate member and the second intermediate member may be configured to convert the pressing force of the first accessory in the first attachment direction and the pressing force of the second accessory in the second attachment direction into the same direction with respect to each other and transmit them to the first linkage member. According to this configuration, since it is not necessary to make the attachment directions of the first accessory and the second accessory the same in order to realize a configuration in which the first linkage member interlocks with both the first intermediate member and the second intermediate member, the design freedom of the power tool is improved.

[0012] In one or more embodiments, the first intermediate member may be configured to pivot when directly or indirectly pressed by the first accessory and interlock with the first linkage member by pressing the first linkage member. The second intermediate member may be configured to pivot when directly or indirectly pressed by the second accessory and interlock with the first linkage member by pressing the first linkage member. According to this configuration, the first intermediate member and the second intermediate member can convert the pressing force of the first accessory acting in the first attachment direction and the pressing force of the second accessory acting in the second attachment direction into the same direction with respect to each other with a small number of members.

[0013] In one or more embodiments, the first mounting portion may include a third side mounting portion located on a third side with respect to a plane containing the rotation axis of the motor, and a fourth side mounting portion located on a fourth side opposite to the third side with respect to the plane, for selectively mounting a first accessory. The third and fourth side mounting portions may be arranged symmetrically with respect to the plane. The first intermediate member may include a third intermediate member located adjacent to the third side mounting portion and a fourth intermediate member located adjacent to the fourth side mounting portion. The third and fourth intermediate members may be arranged symmetrically with respect to the plane. The third intermediate member may be configured to pivot about a first pivot axis. The fourth intermediate member may be configured to pivot about a second pivot axis extending in the same direction as the first pivot axis. The first pivot direction, which is the pivot direction of the third intermediate member when the first accessory is pressed directly or indirectly, may be opposite to the second pivot direction, which is the pivot direction of the fourth intermediate member when the first accessory is pressed directly or indirectly. With this configuration, in a power tool in which the first accessory can be selectively attached to two mounting positions, the first intermediate member and the first interlocking member can be interlocked regardless of which mounting position the first accessory is attached to.

[0014] In one or more embodiments, the power tool may include a first biasing member that biases a third intermediate member in the opposite direction to the first pivot direction, and a second biasing member that biases a fourth intermediate member in the opposite direction to the second pivot direction. Each of the third and fourth intermediate members may be in a non-contact state, not in contact with the first interlocking member, or in a non-pressed state, not pressing the first interlocking member, when not directly or indirectly pressed by the first accessory. With this configuration, when the first accessory is attached to the third mounting portion and the third intermediate member pivots in the first pivot direction and presses the first interlocking member, the fourth intermediate member, which is positioned on the opposite side of the plane from the third intermediate member, does not press the first interlocking member in the opposite direction to the third intermediate member by the biasing force of the second biasing member. Similarly, when the first accessory is attached to the fourth mounting portion and the fourth intermediate member pivots in the second pivot direction to press against the first interlocking member, the third intermediate member does not press against the first interlocking member in the opposite direction to the fourth intermediate member due to the biasing force of the first biasing member. Therefore, the first interlocking member can be smoothly displaced in the intended direction.

[0015] In one or more embodiments, the power tool may include a housing. The first interlocking member may include a first member pivotably supported in the housing. The first member may be configured to interlock with the first intermediate member by being pressed against the third or fourth intermediate member when the first accessory is attached to either the third or fourth mounting portion. The first interlocking member may include a second member configured to engage with the first member and the second intermediate member to interlock with the first member and the second intermediate member. With this configuration, since the first member is pivotably supported in the housing, the first accessory is attached to either the third side mounting portion or the fourth side mounting portion, and even if the first member is pressed against the third side intermediate member or the fourth side intermediate member (i.e., even if the first member is pressed against the third side intermediate member or the fourth side intermediate member on only one side with respect to the plane), the first interlocking member (i.e., the first member and the second member that engages with the first member) can be smoothly pivoted.

[0016] In one or more embodiments, the power tool may be a grinder configured to rotate the tool tip by the driving force of a motor. The first attachment may be a side grip. The second attachment may be a cover that partially covers the tool tip.

[0017] The embodiments will be described in more detail below with reference to the drawings. In the following embodiments, a handheld electric disc grinder (hereinafter simply referred to as a grinder) will be used as an example of a power tool.

[0018] First, an overview of the grinder 10 will be described with reference to Figures 1, 2, 10, and 11. As shown in Figure 10, the grinder 10 is configured to rotate a roughly disc-shaped tip tool 28 mounted on a spindle 25. The spindle 25 is rotated by the rotational driving force provided by an electric motor 31. Various tip tools 28 that can be attached to the grinder 10 are available, such as grinding wheels, rubber pads, brushes, and blades. The user selects the appropriate tip tool 28 according to the desired machining operation and attaches it to the grinder 10. The grinder 10 can perform machining operations such as grinding, polishing, and cutting on the workpiece, depending on the type of tip tool 28.

[0019] In the following explanation, 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. Of the front-rear direction, the side where the tip tool 28 is located is defined as the front side, and the opposite side is defined as the rear side. Furthermore, the direction in which the rotation axis AX2 of the spindle 25 (in other words, the rotation axis of the tip tool 28) extends is defined as the up-down direction of the grinder 10. Of the up-down direction, the side where the tip tool 28 is located is defined as the down side, and the opposite side is defined as the up side. Furthermore, the direction perpendicular to the up-down and front-rear directions is defined as the left-right direction of the grinder 10. Of the left-right direction, the right side when viewed from the rear to the front is defined as the right side of the grinder 10, and the opposite side is defined as the left side of the grinder 10.

[0020] As shown in Figures 1 and 10, the grinder 10 comprises a gear housing 20, a motor housing 30, a handle housing 40, and an intermediate housing 36. 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-rear direction, i.e., the longitudinal direction of the grinder 10. The electric motor 31 (motor shaft 32) is rotatably supported by a front bearing 34 and a rear bearing 35. The electric motor 31 is driven by power supplied from an external source (in this embodiment, AC power, but it may also be DC power). The intermediate housing 36 is located between the gear housing 20 and the motor housing 30 in the front-rear direction and, in this embodiment, is formed from two members. The intermediate housing 36 functions as a bearing support that supports the front bearing 34.

[0021] As shown in Figures 1 and 10, the gear housing 20 houses a mechanism for transmitting the rotational driving force of the electric motor 31 to the tool tip 28. Specifically, the gear housing 20 houses 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 the 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 a second mounting portion 22 at its lower end for detachably attaching a cover 300. The second mounting portion 22 has a cylindrical shape that extends in the vertical direction. The spindle 25 extends vertically within the gear housing 20 and extends downward from the gear housing 20 (more specifically, from the second mounting portion 22).

[0022] As shown in Figure 10, an inner flange 26 is attached around the spindle 25 at its lower end, which extends from the gear housing 20. Below the inner flange 26, a male threaded portion is formed on the spindle 25, and a lock nut 27 is attached to this male threaded portion. The position of the tip tool 28 relative to the spindle 25 is fixed by inserting the tip tool 28 between the inner flange 26 and the lock nut 27 and tightening the lock nut 27.

[0023] The handle housing 40 is the part that the user grips with one hand when using the grinder 10. As shown in Figure 10, the handle housing 40 has a cylindrical shape that extends generally in the front-to-back direction. Inside the handle housing 40 is a switch 41 for driving the electric motor 31.

[0024] As shown in Figures 1 and 10, a controller 43 is further housed within the handle housing 40, near the top of the handle housing 40. The controller 43 is located above the switch 41. The controller 43 and switch 41 are positioned rearward relative to the electric motor 31 in the front-rear direction. The controller 43 is electrically connected to the electric motor 31 and the switch 41. The controller 43 controls the driving of the electric motor 31 by controlling the power supplied to the electric motor 31. In this embodiment, the controller 43 includes a high-temperature protection circuit, an overcurrent protection circuit, and an over-discharge protection circuit. However, one or two of these protection circuits may be omitted.

[0025] As shown in Figures 1 and 10, an operating member 50 is provided on the underside of the motor housing 30 and the handle housing 40, which is configured to be displaceable between an off position, which turns the switch 41 off, and an on position, which turns the switch 41 on. The operating member 50 is an elongated member that extends in the front-rear direction. The operating member 50 has a front end portion 51 and a projection 53. The front end portion 51 is inserted into a through hole that extends in the front-rear direction and is formed in the bottom of the motor housing 30. The front end portion 51 has a concave and convex shape that engages with the motor housing 30, thereby holding the operating member 50 in a retaining state within the motor housing 30. The operating member 50 is configured to pivot counterclockwise from the off position shown in Figure 10 to the on position (not shown), with the engagement point between the front end portion 51 and the motor housing 30 as the pivot point. As shown in Figures 1 and 10, the projection 53 extends upward from the top of the operating member 50.

[0026] As shown in Figures 1 and 10, a lock-off member 54 is attached to the operating member 50. The lock-off member 54 is located approximately in the center of the operating member 50 in the front-rear direction. The lock-off member 54 is supported by the operating member 50 via a pin 57 supported within a boss located inside the operating member 50. The lock-off member 54 is pivotable about the pin 57. The lock-off member 54 is constantly biased in a clockwise direction when viewed from the left by a torsion spring (not shown).

[0027] The lock-off member 54 comprises a contact end 55 and an operating end 56. When the lock-off member 54 is in the initial position shown in Figures 1 and 10, the operating end 56 protrudes downward through the hole in the lock-off member 54. The contact end 55 abuts against a contact portion 33 provided at the rear end and bottom of the motor housing 30 so as to protrude downward from the motor housing 30. Therefore, even if the user performs an operation to push the operating member 50 upward (hereinafter also referred to as the "on operation") in order to displace the operating member 50 from the off position (see Figures 1 and 10) to the on position, the pivoting of the operating member 50 is prevented. On the other hand, if the user pulls the operating end 56 backward with their finger, the lock-off member 54 pivots counterclockwise against the biasing force of the torsion spring. As a result, the contact end 55 pivots to a position where it does not abut the contact portion 33. As a result, the user can pivot the operating member 50 to the on position.

[0028] As shown in Figures 1 and 10, a link member 45 is positioned above the operating member 50. The link member 45 has a through hole that penetrates it in the left-right direction, and a pin 48 is inserted into this through hole. The pin 48 is supported by a boss formed inside the handle housing 40. This configures the link member 45 to be pivotable around the pin 48. The link member 45 is biased counterclockwise when viewed from the left by a torsion spring (not shown).

[0029] The link member 45 comprises two arms 46 and 47 extending radially outward with respect to the pivot axis of the link member 45. The first arm 46 is located on the upper side, and the second arm 47 is located on the lower side. When the link member 45 is in its initial position (see Figures 1 and 10), the tip of the second arm 47 is in contact with the projection 53 of the operating member 50. When the user pushes the operating member 50 upward, displacing the operating member 50 from the off position (see Figures 1 and 10) to the on position (not shown), the second arm 47 is lifted upward by the projection 53. This causes the link member 45 to pivot clockwise against the biasing force of the torsion spring. At this time, the first arm 46 pushes the input member 42 of the switch 41 toward the rear. This switches the switch 41 from the off state to the on state. On the other hand, when the user releases the upward pressure on the operating member 50, the link member 45 returns to its initial position due to the biasing force of the torsion spring, and the switch 41 returns to the off state. At the same time, the operating member 50 is also pressed by the link member 45 and returns to the off position.

[0030] When the user operates the operating member 50 from the off position to the on position as described above, the switch 41 detects this and sends a control signal to the controller 43. Upon receiving this control signal, the controller 43 supplies power to the electric motor 31 to drive it. When the electric motor 31 is driven, 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 reduced in speed. At this time, the direction of rotational motion is also changed from the direction around the motor shaft 32 to the direction around the rotation axis AX2 of the spindle 25. According to this mechanism, as the motor shaft 32 rotates, the spindle 25 rotates around the rotation axis AX2, 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.

[0031] As shown in Figure 11, the grinder 10 is further equipped with two types of accessories: a side handle 200 and a cover 300. The side handle 200 is provided for the user to grip with the hand opposite to the hand gripping the handle housing 40. By using the side handle 200, the user can hold the grinder 10 more stably. The side handle 200 comprises a grip portion 210 for the user to grip and a mounting portion 220 for attachment to the gear housing 20. The mounting portion 220 has a cylindrical shape that extends 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 thread is formed on the outer circumferential surface of the tip of the mounting portion 220.

[0032] As shown in Figures 2 and 11, the gear housing 20 has two first mounting portions 29a and 29b for detachably attaching the side handle 200. The first mounting portion 29a is formed on the left side of the gear housing 20, and the first mounting portion 29b is formed on the right side of the gear housing 20. In other words, the first mounting portion 29a is formed on one side (left side) of the plane P1 which includes the rotation axis AX1 of the electric motor 31 (which in this embodiment also includes the rotation axis AX2 of the spindle 25), and the first mounting portion 29b is positioned on the other side (right side) of the plane P1. The plane P1 is a virtual plane that extends in the front-rear and up-down directions. More specifically, the first mounting portions 29a and 29b are arranged symmetrically with respect to the plane P1. Each of the first mounting portions 29a and 29b is in the form of a through hole that connects the inside and outside of the gear housing 20. The inner surface forming the through hole has a female thread that engages with the male thread of the mounting portion 220 of the side handle 200.

[0033] The side handle 200 can be attached to the gear housing 20 by screwing the mounting portion 220 of the side handle 200 into one of the two first mounting portions 29a and 29b. The user can arbitrarily select the mounting location of the side handle 200 from the first mounting portions 29a and 29b depending on the type of work to be performed using the grinder 10, or whether the user is right-handed or left-handed. Figure 11 shows the side handle 200 selectively attached to the first mounting portion 29a.

[0034] As shown in Figure 10, the cover 300 comprises a cover body 310 that covers a portion of the tip tool 28 and a mounting portion 320 for attachment to the second mounting portion 22. The cover body 310 covers approximately the rear half of the tip tool 28. In this embodiment, the cover body 310 covers the top surface and circumferential surface of the tip tool 28, but depending on the type of tip tool 28 used, it may cover the top surface, the bottom surface, and the circumferential surface between the top and bottom surfaces. The mounting portion 320 has an open, approximately annular shape and extends upward from the top surface of the cover body 310. The mounting portion 320 has two flanges (not shown) at its two circumferential ends, facing each other in the circumferential direction of the rotation axis AX2. With the mounting portion 320 positioned to surround the second mounting portion 22 of the gear housing 20, the radius of the annular shape of the mounting portion 320 is reduced by inserting a bolt (not shown) into the threaded hole formed in the flange and tightening it, thereby fixing the mounting portion 320 to the second mounting portion 22.

[0035] The grinder 10 described above can drive the electric motor 31 only when the side handle 200 is attached to either of the first mounting portions 29a or 29b of the gear housing 20, and the cover 300 is attached to the second mounting portion 22. When at least one of the side handle 200 and the cover 300 is not attached, even if the user operates the operating member 50 to the ON position and a control signal indicating that the switch 41 is ON is sent from the switch 41 to the controller 43, the controller 43 will not drive the electric motor 31 (in other words, will not energize the electric motor 31). On the other hand, when both the side handle 200 and the cover 300 are attached, the controller 43 will allow the electric motor 31 to drive when a control signal indicating that the switch 41 is ON is sent from the switch 41 to the controller 43. Such a configuration will be described in detail below with reference to the drawings.

[0036] The grinder 10 comprises first intermediate members 60a, 60b, a second intermediate member 70, a first interlocking member 80, a second interlocking member 90, and a sensor 44. As shown in Figures 5, 7, and 9, the first intermediate members 60a, 60b have the same shape as each other. The first intermediate member 60a is a member having a rod-shaped portion that extends in a direction slightly angled with respect to the rotation axis AX1. More precisely, the first intermediate member 60a extends from its rear end toward its front end toward away from the rotation axis AX1. A projection 61a is formed at the front end of the rod-shaped portion of the first intermediate member 60a, projecting radially outward with respect to the rotation axis AX1. A pressing portion 63a is formed at the rear end of the rod-shaped portion of the first intermediate member 60a, projecting in a claw shape radially outward. Near the rear end of the first intermediate member 60a, cylindrical shaft portions 62a are formed, projecting upward and downward, respectively (see Figure 7). As shown in Figures 8 and 9, the shaft portions 62a are supported within a boss 36a formed in the intermediate housing 36, and the first intermediate member 60a is pivotable about the first pivot axis AX3 (see Figure 7). Similarly, the first intermediate member 60b includes a projection 61b, a pressing portion 63b, and a shaft portion 62b. The shaft portion 62b is supported within a boss 36b formed in the intermediate housing 36, and the first intermediate member 60b is pivotable about the second pivot axis AX4 (see Figure 7). The first pivot axis AX3 and the second pivot axis AX4 are parallel and both extend in the vertical direction.

[0037] As shown in Figures 8 and 9, a torsion spring 64a is positioned around the shaft portion 62a of the first intermediate member 60a. Similarly, a torsion spring 64b is positioned around the shaft portion 62b of the first intermediate member 60b. The torsion spring 64a biases the first intermediate member 60a in a counterclockwise direction when viewed from above (in other words, in the direction in which the protruding portion 61a is displaced rearward). The torsion spring 64b biases the first intermediate member 60b in a clockwise direction when viewed from above (in other words, in the direction in which the protruding portion 61b is displaced rearward).

[0038] As shown in Figure 5, the first intermediate members 60a and 60b are positioned adjacent to the first mounting portions 29a and 29b, respectively. The first intermediate members 60a and 60b are positioned symmetrically with respect to the plane P1 (see Figures 2 and 11). When the first intermediate members 60a and 60b are in the initial position shown in Figure 5, the protrusions 61a and 61b located at the front ends of the first intermediate members 60a and 60b are housed within the first mounting portions 29a and 29b, respectively.

[0039] As shown in Figures 1, 7, and 9, the second intermediate member 70 is a member having a rod-shaped portion extending in the front-rear direction. A pressing portion 71 projecting downward is formed at the front end of the rod-shaped portion of the second intermediate member 70. As shown in Figure 7, cylindrical shaft portions 72 projecting to the right and left, respectively, are formed at the rear end of the rod-shaped portion of the second intermediate member 70. In addition, an arch-shaped portion 73 extending upward in an arch shape is formed at the rear end of the rod-shaped portion of the second intermediate member 70. The arch-shaped portion 73 has a shape that is symmetrical with respect to the rotation axis AX1. Cylindrical engaging portions 74 projecting to the right and left, respectively, are formed at both ends of the arch-shaped portion 73 (only the left engaging portion 74 is visible in Figure 7).

[0040] As shown in Figures 1, 9, and 10, the second intermediate member 70 is positioned near the bottom of the intermediate housing 36 such that approximately half of its rear side is housed within the intermediate housing 36. Approximately half of the front side of the second intermediate member 70 extends forward through a hole in the intermediate housing 36 and is exposed. The pressed portion 71 located at the front end of the second intermediate member 70 is located near the second mounting portion 22 of the gear housing 20.

[0041] The tip of the shaft portion 72 of the second intermediate member 70 is supported within a boss (not shown) formed in the intermediate housing 36, and the second intermediate member 70 is pivotable about a third pivot axis AX5 (see Figure 7) that extends in the left-right direction. As shown in Figures 8 and 9, a torsion spring 75 is positioned around the shaft portion 72 of the second intermediate member 70. The torsion spring 75 biases the second intermediate member 70 in a counterclockwise direction when viewed from the left side (in other words, in the direction in which the pressed portion 71 is displaced downward).

[0042] The first interlocking member 80 is a member configured to be mechanically interlocked with both the first intermediate members 60a, 60b and the second intermediate member 70 (details will be described later). As shown in Figure 7, in this embodiment, the first interlocking member 80 is composed of two members, namely, a first member 81 and a second member 82. The first member 81 is a substantially U-shaped member with an open bottom. The two lower ends 83 of the first member 81 protrude forward. The lower ends 83 are positioned to overlap with the first intermediate members 60a, 60b in the vertical direction. The lower ends 83 have a tapered shape, becoming narrower towards the front, such that the center of gravity of the first member 81 is located closer to its rear end than its front end.

[0043] As shown in Figures 7 and 9, a pressed portion 84 is formed at the front end of each of the two lower ends 83, projecting radially inward from the lower end 83 with respect to the rotation axis AX1. In this embodiment, the pressed portion 84 has a cylindrical shape. Each of the pressed portions 84 is located in front of and adjacent to the pressing portions 63a, 63b of the first intermediate members 60a, 60b. As shown in Figure 5, when the first intermediate members 60a, 60b are in their initial position, the pressing portions 63a, 63b and the two pressed portions 84 are in contact in the front-rear direction, but the pressing portions 63a, 63b are not pressing the two pressed portions 84 toward the front (referred to as the non-pressed state).

[0044] As shown in Figures 5 and 7, each of the two lower ends 83 is further formed with an engaging portion 86 that protrudes radially inward from the lower end 83 with respect to the rotation axis AX1. The engaging portion 86 is located behind the pressed portion 84. In this embodiment, the engaging portion 86 has a cylindrical shape.

[0045] The upper end of the first member 81 has cylindrical shaft portions 85 that project to the left and right, respectively. The tips of the shaft portions 85 are supported within bosses (not shown) formed in the intermediate housing 36, and the first member 81 is pivotable about a fourth pivot axis AX6 (see Figure 7) that extends in the left-right direction.

[0046] The first member 81 is configured to be mechanically interlocked with the first intermediate members 60a and 60b. Specifically, as shown in Figure 14, when the side handle 200 is attached to the first mounting portion 29a, the tip of the mounting portion 220 of the side handle 200 presses the protruding portion 61a of the first intermediate member 60a inward. As a result, the first intermediate member 60a pivots clockwise when viewed from above, against the biasing force of the torsion spring 64a, from the initial position shown in Figure 5 to the position shown in Figure 14. At this time, as shown in Figure 14, the pressing portion 63a of the first intermediate member 60a, while pivoting, presses the left side of the pressed portion 84 of the first member 81 toward the front. As a result, the first member 81 pivots forward (in other words, so that the lower end portion 83 is displaced forward) from the position shown in Figures 6 and 7 to the position shown in Figures 15 and 16, around the fourth pivot axis AX6 located at the shaft portion 85.

[0047] On the other hand, when the side handle 200 is removed from the first mounting portion 29a, that is, when the side handle 200 is no longer pressing against the protruding portion 61a of the first intermediate member 60a, the first intermediate member 60a pivots in a counterclockwise direction when viewed from above due to the biasing force of the torsion spring 64a, returning from the position shown in Figure 14 to the initial position shown in Figure 5. At this time, the first member 81 returns from the positions shown in Figures 15 and 16 to the positions shown in Figures 6 and 7 due to the biasing force of a biasing member (not shown) provided in the intermediate housing 36.

[0048] Although not shown in the diagram, when the side handle 200 is attached to the first mounting portion 29b, the tip of the mounting portion 220 of the side handle 200 presses the protruding portion 61b of the first intermediate member 60b inward, causing the first intermediate member 60b to pivot against the biasing force of the torsion spring 64b in a counterclockwise direction when viewed from above (that is, in the opposite direction to when the side handle 200 is attached to the first mounting portion 29a and pressed by the side handle 200). At this time, the pressing portion 63b of the first intermediate member 60b, while pivoting, presses the pressed portion 84 on the right side of the first member 81 toward the front. As a result, the first member 81 pivots forward around the fourth pivot axis AX6 located on the shaft portion 85, similar to when the side handle 200 is attached to the first mounting portion 29a. Similarly, when the side handle 200 is removed from the first mounting portion 29b, the first intermediate member 60b and the first member 81 return to their respective initial positions.

[0049] Thus, the first member 81 is configured to be pressed against the first intermediate member 60a or the first intermediate member 60b when the side handle 200 is selectively attached to either the first mounting portion 29a or 29b, thereby acting in conjunction with the first intermediate member 60a or the first intermediate member 60b.

[0050] As shown in Figure 7, the second member 82 is a substantially U-shaped member with an open bottom. As shown in Figures 5 and 7, the second member 82 is positioned radially inward from the first member 81. As shown in Figure 7, the second member 82 has a projecting upper end 89 at its upper end that projects upward. The projecting upper end 89 has a right side wall and a left side wall. The projecting upper end 89 further includes a beam portion 891 that connects the right side wall and the left side wall at their upper and rear positions. The beam portion 891 has a cylindrical shape that extends in the left-right direction. Below the beam portion 891, a through hole 892 (see Figures 3 and 12) is formed that extends in the front-rear direction. The two lower ends of the second member 82 extend below the lower end 83 of the first member 81. Each of the two lower ends of the second member 82 has an engaging portion 87 formed therein, which is a roughly U-shaped notch with an open lower side. Two engaging portions 74 of the second intermediate member 70 are inserted into the notches of the two engaging portions 87, respectively. This configuration engages the second member 82 and the second intermediate member 70.

[0051] The second member 82 is configured to be mechanically interlocked with the second intermediate member 70 and the first member 81. First, the interlocking of the second member 82 and the second intermediate member 70 will be described. As shown in Figures 10 and 12, when the cover 300 (more specifically, the mounting portion 320) is attached to the second mounting portion 22, the upper end of the mounting portion 320 presses the pressed portion 71 of the second intermediate member 70 upward. As a result, the second intermediate member 70 pivots against the biasing force of the torsion spring 75, around the third pivot axis AX5 located on the shaft portion 72, in a clockwise direction when viewed from the left, from the position shown in Figures 6 and 7 to the position shown in Figures 17 and 18. At this time, the engaging portion 87 that engages with the engaging portion 74 of the second intermediate member 70 is pressed toward the rear, and the second member 82 pivots counterclockwise when viewed from the left, around the fifth pivot axis AX7 (see Figure 7) located at the engaging portion 74, from the position shown in Figures 6 and 7 to the position shown in Figures 17 and 18.

[0052] On the other hand, when the cover 300 is removed from the second mounting portion 22, that is, when the cover 300 is no longer pressing against the pressed portion 71 of the second intermediate member 70, the second intermediate member 70 pivots counterclockwise when viewed from the left side due to the biasing force of the torsion spring 75, returning from the position shown in Figures 17 and 18 to the position shown in Figures 6 and 7. At this time, the engaging portion 87 of the second member 82, which engages with the engaging portion 74 of the second intermediate member 70, is pressed forward, so the second member 82 also pivots and returns from the position shown in Figures 17 and 18 to the position shown in Figures 6 and 7.

[0053] Thus, the second member 82 is pressed against the second intermediate member 70 when the cover 300 is attached to the second mounting portion 22, thereby being configured to move in conjunction with the second intermediate member 70.

[0054] Next, the interlocking of the second member 82 and the first member 81 will be explained. As shown in Figures 5 and 7, two engagement holes 88 are formed in each of the portions of the second member 82 that extend vertically on the left and right sides of the rotation axis AX1 (hereinafter referred to as the left portion and the right portion) (in Figure 7, only the right engagement hole 88 is visible). The two engagement holes 88 are in the form of holes that penetrate the left portion and the right portion in the left-right direction. In the vertical direction, the engagement holes 88 are located closer to the engagement portion 74 of the second intermediate member 70 than to the shaft portion 85 of the first member 81. The engagement portion 86 of the first interlocking member 80 is inserted into the two engagement holes 88. With this configuration, the second member 82 and the first member 81 are engaged.

[0055] Therefore, when the side handle 200 is attached, the first member 81 is pressed against the first intermediate member 60a or the first intermediate member 60b and pivots around the fourth pivot axis AX6, causing the engaging portion 86 to press the second member 82 forward. As a result, the second member 82 pivots around the fifth pivot axis AX7 (see Figure 7), which extends in the left-right direction, from the position shown in Figures 6 and 7 to the position shown in Figures 15 and 16. The fifth pivot axis AX7 is located at the engaging portion 74. Also, when the side handle 200 is removed and the first member 81 pivots in the opposite direction, the engaging portion 86 presses the second member 82 backward. As a result, the second member 82 pivots and returns from the position shown in Figures 15 and 16 to the position shown in Figures 6 and 7.

[0056] Furthermore, when the cover 300 is attached, the second intermediate member 70 pivots, and in conjunction with the second intermediate member 70, the second member 82 pivots in a counterclockwise direction when viewed from the left, causing the second member 82 to press the engaging portion 86 of the first member 81 forward. As a result, the first member 81 pivots clockwise when viewed from the left, around the fourth pivot axis AX6 located on the shaft portion 85, from the position shown in Figures 6 and 7 to the position shown in Figures 17 and 18. Also, when the cover 300 is removed and the second member 82 pivots in the opposite direction, the second member 82 presses the engaging portion 86 backward. As a result, the first member 81 pivots back from the position shown in Figures 17 and 18 to the position shown in Figures 6 and 7.

[0057] With this configuration, the second member 82 can be linked with both the second intermediate member 70 and the first member 81. As is clear from the above description, the second member 82 is displaced in the same direction when the side handle 200 is attached and when the cover 300 is attached.

[0058] The aforementioned interlocking of the first intermediate members 60a, 60b, the second intermediate member 70, and the first interlocking member 80 (first member 81 and second member 82) results in a cumulative displacement of the first interlocking member 80 when both the side handle 200 and the cover 300 are installed. Specifically, when the side handle 200 is installed first, as described above, the first interlocking member 80 is displaced (pivoted) from the initial position shown in Figures 6 and 7 to the position shown in Figures 15 and 16. Then, when the cover 300 is installed in addition to the side handle 200, the first interlocking member 80 is further displaced (pivoted) in the same direction as when the side handle 200 was installed, from the position shown in Figures 15 and 16 to the position shown in Figures 19 and 20. Furthermore, when the cover 300 is installed first, as described above, the first interlocking member 80 is displaced (pivoted) from the initial position shown in Figures 6 and 7 to the position shown in Figures 17 and 18. Then, when the side handle 200 is installed in addition to the cover 300, the first interlocking member 80 is further displaced (pivoted) in the same direction as when the cover 300 was installed, from the position shown in Figures 17 and 18 to the position shown in Figures 19 and 20. In this way, when both the side handle 200 and the cover 300 are installed, the first interlocking member 80 is cumulatively displaced from the initial position shown in Figures 6 and 7 to the position shown in Figures 19 and 20, regardless of the installation order of the side handle 200 and the cover 300.

[0059] The second interlocking member 90 is configured to mechanically interlock with such cumulative displacement of the first interlocking member 80. As shown in Figures 6 and 7, the second interlocking member 90 is a rod-shaped member extending in the front-rear direction. As shown in Figures 1 and 10, the second interlocking member 90 extends from in front of the electric motor 31 to behind the electric motor 31. The second interlocking member 90 is positioned along the inner upper surface of the motor housing 30 so as to be displaceable in the front-rear direction. As shown in Figures 3 and 12, the second interlocking member 90 extends forward of the second member 82 by passing through a through hole 892 formed in the protruding upper end 89 of the second member 82 of the first interlocking member 80.

[0060] As shown in Figures 6 and 7, an engaging portion 91 projecting upward is formed at the front end of the second interlocking member 90. The engaging portion 91 extends above the beam portion 891 of the protruding upper end 89. An arc-shaped recess 97 is formed at the rear base of the engaging portion 91. Protrusions 92 and 93 are formed near the rear end of the second interlocking member 90. The protrusions 92 and 93 project downward and are spaced apart in the front-rear direction. A positioning projection 94 projecting forward is formed on the front end surface of the protrusion 92. A positioning projection 95 projecting rearward is formed on the rear end surface of the protrusion 93.

[0061] As shown in Figures 4 and 13, a coil spring 96, as an example of a biasing member, is positioned between the protrusions 92 and 93. The rear end of the coil spring 96 rests on the front end surface of the protrusion 92, and the front end of the coil spring 96 rests on the portion of the motor housing 30 that protrudes between the protrusions 92 and 93. The coil spring 96 is positioned to surround the positioning protrusions 94 and 95, thereby restricting the movement of the coil spring 96 in a direction perpendicular to the front-rear direction. The coil spring 96 is positioned in a compressed state, constantly biasing the second interlocking member 90 toward the rear. The protrusion 93 functions as a stopper that restricts the rearward movement of the second interlocking member 90 by contacting the portion of the motor housing 30 that protrudes between the protrusions 92 and 93.

[0062] When the second interlocking member 90 is in the initial position shown in Figures 6 and 7, the engaging portion 91 of the second interlocking member 90 and the beam portion 891 of the second member 82 are spaced apart in the front-rear direction. When only the side handle 200 of the side handle 200 and cover 300 is attached, the second member 82 of the first interlocking member 80 pivots, causing the engaging portion 91 and the beam portion 891 of the second member 82 to come into contact, as shown in Figures 15 and 16. At this time, the beam portion 891 does not press the engaging portion 91 forward. Therefore, the second interlocking member 90 remains in the initial position. When only the cover 300 of the side handle 200 and cover 300 is attached, the second member 82 of the first interlocking member 80 pivots, causing the engaging portion 91 and the beam portion 891 of the second member 82 to come into contact, as shown in Figures 17 and 18. At this time, the beam portion 891 is not pressing the engaging portion 91 forward. Therefore, the second interlocking member 90 remains in its initial position.

[0063] When both the side handle 200 and the cover 300 are attached, the second member 82 of the first interlocking member 80 pivots further, causing the beam portion 891 of the second member 82 to press the engaging portion 91 forward, as shown in Figures 19 and 20. As a result, the second interlocking member 90 is displaced forward from the position shown in Figure 3 to the position shown in Figure 12, against the biasing force of the coil spring 96. Since a recess 97 is formed at the base of the engaging portion 91, when the second interlocking member 90 is displaced forward, the beam portion 891 is housed in the recess 97, as shown in Figure 12. Therefore, the beam portion 891 does not act a downward force on the second interlocking member 90. Consequently, the second interlocking member 90 can be displaced smoothly forward.

[0064] On the other hand, when at least one of the side handle 200 and the cover 300 is removed, the second member 82 returns from the position shown in Figures 19 and 20 to the position shown in Figures 15 and 16, or to the position shown in Figures 17 and 18. This releases the force with which the beam portion 891 of the second member 82 presses the engaging portion 91 forward, and the second interlocking member 90 returns to the initial position shown in Figure 3 due to the biasing force of the coil spring 96.

[0065] Thus, the second interlocking member 90 interlocks with the first interlocking member 80 so as to move depending on whether or not the first interlocking member 80 is being displaced cumulatively. In other words, the second interlocking member 90 moves forward only when the first interlocking member 80 is being displaced cumulatively, and moves backward only when the cumulative displacement is released.

[0066] The displacement of the second interlocking member 90 (in other words, the cumulative displacement of the first interlocking member 80) is detected by the sensor 44. Specifically, as shown in Figures 4 and 13, the sensor 44 is mounted on the substrate 441 so as to face the protrusion 92 of the second interlocking member 90 in the vertical direction. The sensor 44 is positioned behind the electric motor 31. In this embodiment, the sensor 44 is a Hall sensor. A magnet 49 is embedded in the protrusion 92 so as to be exposed facing downward. As shown in Figures 4 and 13, when the second interlocking member 90 is displaced in the front-rear direction, the magnet 49 crosses the sensor 44 in the front-rear direction. In this embodiment, the sensor 44 is a bipolar detection type, and the magnet 49 is configured so that the N pole and S pole are aligned in the front-rear direction. Therefore, the displacement of the second interlocking member 90 (the cumulative displacement of the first interlocking member 80) can be detected depending on whether the sensor 44 detects the N pole or the S pole. The type of sensor 44 is not particularly limited and may be, for example, a unipolar detection type Hall sensor, or any known type of magnetic sensor other than a Hall sensor (e.g., an MR sensor). The arrangement of the switch 41 and the magnet 49 may be changed as appropriate depending on the characteristics of the sensor 44.

[0067] This sensor 44 is electrically connected to the controller 43, and the output of the sensor 44 is input to the controller 43. If the sensor 44 does not detect the displacement of the second interlocking member 90 (the cumulative displacement of the first interlocking member 80), that is, if at least one of the side handle 200 and the cover 300 is not installed, the controller 43 prohibits the driving of the electric motor 31 (in other words, the energization of the electric motor 31). On the other hand, if the sensor 44 does detect the displacement of the second interlocking member 90 (the cumulative displacement of the first interlocking member 80), that is, if both the side handle 200 and the cover 300 are installed, the controller 43 allows the driving of the electric motor 31 when a control signal indicating that the switch 41 is in the ON state is sent from the switch 41 to the controller 43. Such prohibition / allowance control over the operation of the electric motor 31 may be implemented by software executed by the CPU of the controller 43, or it may be implemented solely by hardware (for example, a switching element may be used that turns the electrical connection between the controller 43 and the electric motor 31 on or off in response to input from the sensor 44).

[0068] According to the grinder 10 described above, both the side handle 200 and the cover 300 are attached, thereby providing a novel structure in which power is supplied to the electric motor 31 only when the first interlocking member 80 is cumulatively displaced in conjunction with the first intermediate members 60a, 60b and the second intermediate member 70. Therefore, the design freedom of a grinder having a structure in which power is supplied to the motor only when both the side handle and the cover are attached can be increased. For example, as in the embodiment described above, the first intermediate members 60a, 60b, the second intermediate member 70 and the first interlocking member 80 can be concentrated in the available space within the intermediate housing 36. Furthermore, since the first interlocking member 80 is interlocked with both the first intermediate members 60a, 60b and the second intermediate member 70 (in other words, the first interlocking member 80 is shared by the first intermediate members 60a, 60b and the second intermediate member 70), a configuration that allows power to be supplied to the electric motor 31 only when both the side handle 200 and the cover 300 are attached can be efficiently realized. For example, the fact that both the side handle 200 and the cover 300 are attached can be detected by a single sensor 44. Reducing the number of sensors reduces the number of electronic components and, consequently, the wiring work, making manufacturing easier.

[0069] Furthermore, in the grinder 10, the first intermediate members 60a, 60b, the second intermediate member 70, and the first interlocking member 80 are positioned in front of the electric motor 31, while the sensor 44 and controller 43 (i.e., electronic components) are positioned behind the electric motor 31. The cumulative displacement of the first interlocking member 80 is detected by the sensor 44 via the second interlocking member 90. Therefore, the part in front of the electric motor 31 (for example, the intermediate housing 36) does not need to be insulated. This allows the grinder 10 to be made more compact. Also, since the wiring for electrically connecting the sensor 44 and the controller 43 does not need to be routed across the electric motor 31, the length of the wiring can be shortened and the ease of wiring is improved.

[0070] Furthermore, in the grinder 10, although the mounting direction (approximately left-right) for attaching the side handle 200 to the first mounting portion 29a or the first mounting portion 29b and the mounting direction (up-down) for attaching the cover 300 to the second mounting portion 22 are different, the pressing forces of the side handle 200 and the cover 300 acting in these two mounting directions are converted to the same direction (front-back direction) by the first intermediate members 60a, 60b and the second intermediate member 70. Therefore, since it is not necessary to make the two mounting directions coincide, the design freedom of the grinder 10 is improved.

[0071] Furthermore, according to the grinder 10, the first intermediate members 60a and 60b pivot when pressed by the side handle 200 and press against the first interlocking member 80 (first member 81), thereby interlocking with the first interlocking member 80. Similarly, the second intermediate member 70 pivots when pressed by the cover 300 and presses against the first interlocking member 80 (second member 82), thereby interlocking with the first interlocking member 80. In this way, by configuring the first intermediate members 60a and 60b and the second intermediate member 70 to pivot, the pressing forces of the side handle 200 and the cover 300 acting in the two mounting directions can be converted to the same direction with a small number of components.

[0072] Furthermore, in the grinder 10, the first mounting portions 29a, 29b and the first intermediate members 60a, 60b are arranged symmetrically with respect to the plane P1 (see Figure 11) which includes the rotation axis AX1 of the electric motor 31. The pivot directions of the first intermediate members 60a, 60b when the side handle 200 is attached are opposite to each other. Therefore, regardless of whether the side handle 200 is attached to the first mounting portion 29a or 29b, the first intermediate members 60a, 60b corresponding to that mounting position can be linked with the first interlocking member 80. As a result, the user can select the mounting position of the side handle 200 from the first mounting portions 29a, 29b, which is highly convenient for the user.

[0073] Furthermore, according to the grinder 10, the first intermediate members 60a and 60b, which are biased in opposite directions by the torsion springs 64a and 64b respectively, are in an unpressed state in their initial position (see Figure 5) where they are not pressed by the side handle 200, and do not press against the first interlocking member 80 (first member 81). Therefore, when the side handle 200 is attached to the first mounting portion 29a and the first intermediate member 60a pivots to press against the first interlocking member 80 (first member 81), the first intermediate member 60b, which is positioned on the opposite side of the plane P1 (see Figure 11) from the first intermediate member 60a, does not press against the first interlocking member 80 (first member 81) in the opposite direction to the first intermediate member 60a due to the biasing force of the torsion spring 64b. Similarly, when the side handle 200 is attached to the first mounting portion 29b, no pressing force opposite to the pressing force of the first intermediate member 60b acts on the first interlocking member 80 (first member 81) from the first intermediate member 60a. Therefore, the first interlocking member 80 can be smoothly displaced in the intended direction. The same effect can be obtained even if the first intermediate members 60a and 60b are in a non-contact state with the first interlocking member 80 (first member 81) in their initial position (see Figure 5).

[0074] Furthermore, according to the grinder 10, the first interlocking member 80 comprises a first member 81 and a second member 82. The first member 81 is pivotably supported in the intermediate housing 36 and interlocks with the first intermediate member 60a or the first intermediate member 60b by being pressed by the first intermediate member 60a or the first intermediate member 60b when the side handle 200 is attached. The second member 82 engages with the first member 81 and interlocks with the second intermediate member 70 and the first member 81. With this configuration, since the first member 81 is pivotably supported in the intermediate housing 36, the side handle 200 can be attached, and even if the first member 81 is pressed against only one of the first intermediate members 60a and the first intermediate member 60b (i.e., pressed against only one of the right or left side of the first member 81), the first member 81, and by extension the first interlocking member 80, can be smoothly pivoted.

[0075] While embodiments of the present invention have been described above, these embodiments are provided to facilitate understanding of the present invention and do not limit it. The present invention can be modified and improved without departing from its spirit, and equivalents thereof are included. Furthermore, any combination or omission of the elements described in the claims and specification is possible to the extent that at least some of the above-described problems can be solved or at least some of the effects can be achieved.

[0076] For example, if the sensor 44 is positioned in front of the electric motor 31, the second interlocking member 90 may be omitted. In this case, the magnet 49 may be embedded in the first interlocking member 80 (second member 82), and the sensor 44 may directly detect the cumulative displacement of the first interlocking member 80.

[0077] Furthermore, instead of sensor 44, any type of sensor that directly or indirectly (for example, via the second interlocking member 90) detects the cumulative displacement of the first interlocking member 80 may be used. Such a sensor may be a microswitch, a photoelectric sensor, an ultrasonic distance sensor, or the like.

[0078] Furthermore, the first intermediate members 60a and 60b may be indirectly pressed against the side handle 200 via other additional movable members when the side handle 200 is attached. Similarly, the second intermediate member 70 may be indirectly pressed against the cover 300 via other additional movable members when the cover 300 is attached.

[0079] Furthermore, the mechanism for transmitting the displacement of the first intermediate members 60a, 60b and the second intermediate member 70 to the first interlocking member 80, and the mechanism for transmitting the displacement of the first interlocking member 80 to the second interlocking member 90, are not limited to the embodiments described above, but may be implemented by any mechanical mechanism (for example, a link mechanism).

[0080] Furthermore, the number of first mounting portions for attaching the side handle 200 may be one. In this case, the number of first intermediate members will also be one. Also, the first interlocking member 80 may have any structure that allows for the cumulative displacement described above, and may be formed from a single member, for example.

[0081] Furthermore, a configuration in which both the side handle 200 and the cover 300 are attached, and the electric motor 31 is allowed to be driven only when the first interlocking member 80 is cumulatively displaced, may be implemented mechanically instead of electrically by the controller 43. For example, an operating member (e.g., a slide switch) for switching the switch between on and off states may be located on the upper surface of the intermediate housing 36. In this case, when the first interlocking member 80 is not cumulatively displaced, the operating member, or an additional interlocking member linked to the operating member, may contact the first interlocking member 80, or an additional interlocking member linked to the first interlocking member 80, thereby restricting the operating member from being displaced from the off position to the on position. Also, when the first interlocking member 80 is cumulatively displaced, the electric motor 31 may be allowed to be driven by retracting the first interlocking member 80, or an additional interlocking member linked to the first interlocking member 80, to a position that does not hinder the operating member from being displaced from the off position to the on position. In such alternative embodiments, the sensor 44 may be omitted.

[0082] Furthermore, the above-described embodiment is not limited to the grinder 10, but is applicable to any power tool configured to allow the attachment of two types of accessories.

[0083] The correspondence between each component of the above embodiment and each component of the present invention is shown below. However, each component of the embodiment is merely an example and does not limit the components of the present invention. Grinder 10 is an example of a "power tool". Electric motor 31 is an example of a "motor". Side handle 200 is an example of a "first accessory". Cover 300 is an example of a "second accessory". First mounting parts 29a and 29b are examples of "first mounting parts", and also examples of "third side mounting part" and "fourth side mounting part", respectively. Second mounting part 22 is an example of a "second mounting part". First intermediate members 60a and 60b are examples of "first intermediate members", and also examples of "third side intermediate member" and "fourth side intermediate member", respectively. Second intermediate member 70 is an example of a "second intermediate member". First interlocking member 80 is an example of a "first interlocking member". Sensor 44 is an example of a "sensor". Controller 43 is an example of a "controller". Second interlocking member 90 is an example of a "second interlocking member". Plane P1 is an example of a "plane". First pivot axis AX3 is an example of a "first pivot axis". Second pivot axis AX4 is an example of a "second pivot axis". Torsion springs 64a and 64b are examples of a "first biasing member" and a "second biasing member", respectively. Intermediate housing 36 is an example of a "housing". First member 81 and second member 82 are examples of a "first member" and a "second member", respectively. Tip tool 28 is an example of a "tip tool". [Explanation of Symbols]

[0084] 10...Grinder 20... Gear Housing 22...Second mounting section 23...Small bevel gear 24...Large Bevel Gear 25... Spindle 26...Inner flange 27... Lock nuts 28... Tip tool 29a, 29b... First mounting section 30...Motor housing 31... Electric motor 32...Motor shaft 33...Abutment part 34...Front bearing 35...Rear bearing 36...Intermediate Housing 36a, 36b... Boss 40...Handle housing 41... Switch 42...Input component 43... Controller 44...Sensor 45... Link member 46, 47... Arm 48...pin 49...Magnets 50...Operating components 51...front end 53...protrusion 54... Lock-off component 55...Abutting end 56...Operation end 57...pin 60a, 60b... First intermediate member 61a,61b...Protrusion 62a,62b...Shaft part 63a, 63b... Pressing part 64a, 64b... Torsion springs 70...Second intermediate member 71...Pressed portion 72...Shaft 73...Arched section 74...Engaging part 75... Torsion spring 80...First interlocking member 81...First component 82...Second component 83...lower end 84...Pressed portion 85...Shaft 86, 87...Engaging parts 88...Engagement hole 89...Protruding upper end 90...Second interlocking member 91...Engaging part 92,93...protrusion 94, 95... Positioning protrusions 96... Coil spring 97...recess 200... Side handle 210... Grip section 220...Mounting part 300...cover 310...Cover body 320...Mounting part 441... Circuit board 891...beam section 892...Through hole P1...Plane AX1, AX2... Rotation axis AX3...First pivot axis AX4...Second pivot axis AX5...Third pivot axis AX6...Fourth pivot axis AX7...Fifth pivot axis

Claims

1. It is a power tool, Motor and, A first mounting section for detachably attaching a side grip as a first accessory, A second mounting section for detachably attaching a cover as a second accessory, A first intermediate member configured to be directly or indirectly pressed and displaced by the side grip when the side grip is attached to the first mounting portion, A second intermediate member configured to be directly or indirectly pressed and displaced by the cover when the cover is attached to the second mounting portion, A first interlocking member is configured to be mechanically interlocked with the displacement of the first intermediate member and the second intermediate member, and is configured to be displaced in the same direction when the side grip is attached to the first mounting portion and when the cover is attached to the second mounting portion. Equipped with, The first interlocking member is, When the side grip is attached to the first mounting portion while the cover is not attached to the second mounting portion, it is displaced from the first position to the second position. With the side grip attached to the first mounting portion, when the cover is attached to the second mounting portion, it is displaced from the second position to the third position opposite to the first position. When the cover is attached to the second mounting portion while the side grip is not attached to the first mounting portion, the cover is displaced from the first position to the fourth position. With the side grip attached to the first mounting portion, the cover is attached to the second mounting portion, and the side grip is configured to be displaced from the fourth position to the third position. The power tool is configured such that power is supplied to the motor only when the first interlocking member is displaced to the third position. The number of the first mounting portion is one. Power tools.

2. A power tool, Motor and, A first mounting section for detachably attaching a side grip as a first accessory, A second mounting section for detachably attaching a cover as a second accessory, A first intermediate member configured to be directly or indirectly pressed and displaced by the side grip when the side grip is attached to the first mounting portion, A second intermediate member configured to be directly or indirectly pressed and displaced by the cover when the cover is attached to the second mounting portion, A first interlocking member is configured to be mechanically interlocked with the displacement of the first intermediate member and the second intermediate member, and is configured to be displaced in the same direction when the side grip is attached to the first mounting portion and when the cover is attached to the second mounting portion. Equipped with, The first interlocking member is, When the side grip is attached to the first mounting portion while the cover is not attached to the second mounting portion, it is displaced from the first position to the second position. With the side grip attached to the first mounting portion, when the cover is attached to the second mounting portion, it is displaced from the second position to the third position opposite to the first position. When the cover is attached to the second mounting portion while the side grip is not attached to the first mounting portion, the cover is displaced from the first position to the fourth position. With the side grip attached to the first mounting portion, the cover is attached to the second mounting portion, and the side grip is configured to be displaced from the fourth position to the third position. The power tool is configured such that power is supplied to the motor only when the first interlocking member is displaced to the third position. The first mounting portion includes a first side mounting portion located on the first side of the motor in the axial direction, which is the direction in which the rotation axis of the motor extends, and a second side mounting portion located on the second side opposite to the first side of the motor in the axial direction. The first interlocking member is configured to perform the same displacement when the side grip is attached to the first side mounting portion and when the side grip is attached to the second side mounting portion. Power tools.

3. A power tool according to claim 1 or claim 2, A sensor configured to directly or indirectly detect the displacement of the first interlocking member to the third position, A controller configured to control the supply of power to the motor, and configured to allow power to be supplied to the motor only when the displacement of the first interlocking member to the third position is detected by the sensor, Power tools equipped with [specific features / features].

4. The power tool according to claim 3, The system includes a second interlocking member configured to be mechanically interlocked with the displacement of the first interlocking member, The first intermediate member, the second intermediate member, and the first interlocking member are arranged on the first side relative to the motor in the axial direction, which is the direction in which the rotation axis of the motor extends. The sensor and the controller are arranged in the axial direction on the second side opposite to the first side with respect to the motor. The second interlocking member extends from the first side to the second side, The sensor is configured to detect the displacement of the first interlocking member up to the third position based on the displacement of the second interlocking member. Power tools.

5. A power tool according to any one of claims 1 to 4, The first mounting direction for attaching the side grip to the first mounting portion and the second mounting direction for attaching the cover to the second mounting portion are different from each other. The first intermediate member and the second intermediate member are configured to convert the pressing force of the side grip in the first mounting direction and the pressing force of the cover in the second mounting direction into the same direction and transmit them to the first interlocking member. Power tools.

6. The power tool according to claim 5, The first intermediate member is configured to pivot when pressed directly or indirectly against the side grip, thereby pressing against the first interlocking member and interlocking with the first interlocking member. The second intermediate member is configured to pivot when pressed directly or indirectly against the cover, thereby pressing against the first interlocking member and thus interlocking with the first interlocking member. Power tools.

7. The power tool according to claim 6, The first mounting portion comprises a third mounting portion positioned on a third side with respect to a plane containing the rotation axis of the motor, and a fourth mounting portion positioned on a fourth side opposite to the third side with respect to the plane, for selectively mounting the side grip. The third mounting portion and the fourth mounting portion are arranged symmetrically with respect to the plane. The first intermediate member comprises a third intermediate member positioned adjacent to the third mounting portion and a fourth intermediate member positioned adjacent to the fourth mounting portion. The third intermediate member and the fourth intermediate member are arranged symmetrically with respect to the plane. The third intermediate member is configured to pivot about the first pivot axis, The fourth intermediate member is configured to pivot about a second pivot axis that extends in the same direction as the first pivot axis. The first pivot direction, which is the pivot direction of the third intermediate member when pressed directly or indirectly by the side grip, is opposite to the second pivot direction, which is the pivot direction of the fourth intermediate member when pressed directly or indirectly by the side grip. Power tools.

8. The power tool according to claim 7, A first biasing member that biases the third intermediate member in a direction opposite to the first pivot direction, A second biasing member that biases the fourth intermediate member in a direction opposite to the second pivot direction, Equipped with, Each of the third and fourth intermediate members is in a non-contact state, not in contact with the first interlocking member, or in a non-pressed state, not pressing on the first interlocking member, when not being pressed directly or indirectly against the side grip. Power tools.

9. A power tool according to claim 7 or claim 8, Equipped with a housing, The first interlocking member is, A first member pivotably supported in the housing, wherein the first member is configured to interlock with the first intermediate member by being pressed against the third intermediate member or the fourth intermediate member when the side grip is attached to either the third mounting portion or the fourth mounting portion, A second member is configured to engage with the first member and the second intermediate member and to interlock with the first member and the second intermediate member. Equipped with Power tools.

10. A power tool according to any one of claims 1 to 9, The aforementioned power tool is a grinder configured to rotate the tip tool by the driving force of the motor, The cover partially covers the tip tool. Power tools.

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