power tools

Abstract

To provide improvement relating to a mounting structure of a cover of a tip tool.SOLUTION: An electric tool includes a spindle, a housing, a cover body which is removably mounted on the housing and partially covers the tip tool mounted on the lower end of the spindle, a first engagement part provided on the cover body, and a second engagement part provided on the housing. The cover body includes an upper plate part, and an outer peripheral part which is provided along the outer edge of the upper plate part and projects downward from the outer edge. The second engagement part is movable between an engagement position engaged with the first engagement part, and a release position that cannot be engaged with the first engagement part. The first engagement part and the second engagement part are engaged with each other, which regulates rotation around the driving shaft of the cover body relative to the housing. The first engagement part is at the same position as the outer peripheral part of the cover body or radially outward from the outer peripheral part in a radial direction perpendicular to the driving shaft, and is between the upper end and the lower end of the cover body in the vertical direction.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a power tool. More specifically, the present disclosure relates to a power tool including a cover that partially covers a tip tool attached to a spindle. Background Art

[0002] A power tool (for example, a power tool that rotates or oscillates a tip tool) may be provided with a cover that partially covers the tip tool attached to the lower end of a spindle, in order to suppress scattering of dust and sparks generated during machining work. In view of workability when the power tool is used in a narrow space, it is preferable that the size of the power tool in the axial direction of the spindle is small. Accordingly, improvements for reducing the size in the axial direction of the spindle have been proposed regarding the cover attachment structure. For example, Patent Document 1 discloses a grinder provided with a lever arranged radially outward of a protective hood (cover) and engageable with the protective hood. Prior Art Literature Patent Literature

[0003] Patent Document 1 European Patent No. 2189244 Specification Summary of the Invention Problem to be Solved by the Invention

[0004] In the grinder described above, the protective hood includes a disc-shaped portion arranged above the tip tool, and an edge portion connected to an outer edge of the disc-shaped portion and surrounding an edge of the tip tool. The lever is arranged radially outward of the protective hood, and is engageable with a recess formed in a portion of the edge portion of the protective hood that is arranged on the lower side relative to the tip tool. There is room for further improvement in such a cover attachment structure.

[0005] In view of the above circumstances, a non-limiting object of the present disclosure is to provide an improvement related to an attachment structure for a cover of a tip tool. [Means for solving the problem]

[0006] According to one non-limiting aspect of the present disclosure, a power tool is provided comprising a spindle, a housing, a cover body, a first engaging portion, and a second engaging portion. Examples of power tools in this aspect include rotary tools that rotate the tip tool around a drive shaft (e.g., grinders, cutters, circular saws), and vibratory tools that oscillate (reciprocate) the tip tool around a drive shaft (so-called multi-tools).

[0007] The spindle extends along the drive shaft that defines the vertical direction of the power tool. The spindle has a lower end from which a tool tip can be attached and detached. The housing houses the spindle with the lower end of the spindle exposed to the outside. The cover body is detachably attached to the housing and is configured to partially cover the tool tip mounted on the lower end of the spindle. The cover body includes a top plate portion positioned above the tool tip and an outer periphery portion that protrudes downward from the outer edge along the outer edge of the top plate portion. A first engaging portion is provided on the cover body. A second engaging portion is provided on the housing and is movable between an engaged position in which it engages with the first engaging portion and a disengaged position in which it cannot engage with the first engaging portion. The first and second engaging portions are configured to engage with each other to restrict the rotation of the cover body around the drive shaft relative to the housing. The first engaging portion is located at the same position as or radially outward from the outer periphery of the cover body in the radial direction perpendicular to the drive shaft, and is located between the upper and lower ends of the cover body in the vertical direction. In this context, "located in the same position as the outer periphery" specifically refers to cases where, for example, the first engaging portion is a recess or hole formed in the outer periphery. Furthermore, "between the upper and lower ends" includes the same position as the upper end and the same position as the lower end.

[0008] In this embodiment of the power tool, a first engaging portion provided on the cover body and a second engaging portion provided on the housing engage with each other to restrict the rotation of the cover body. The first engaging portion is located between the upper and lower ends of the cover body in the vertical direction. In other words, the first engaging portion does not protrude above or below the cover body. Therefore, compared to the case where the first engaging portion protrudes above or below the cover body, it is possible to suppress an increase in the overall vertical size of the power tool, including the second engaging portion. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of the grinder according to the first embodiment. [Figure 2] This is a cross-sectional view of a grinder. [Figure 3] This is a magnified view of a portion of Figure 2. [Figure 4] This is a perspective view of the cover. [Figure 5] This is a perspective view of the front end of the grinder. [Figure 6] This is a partially disassembled perspective view of a grinder with the tip tool and cover removed. [Figure 7] This is a partial left side view of the grinder with the cover removed and the lever in the engaged position. [Figure 8] This is a cross-sectional view showing the lever and rail in the engaged position. [Figure 9] This is a partial left side view of the grinder with the cover removed and the lever in the release position. [Figure 10] This is a cross-sectional view showing the lever and rail in the release position. [Figure 11] This is a partial left side view of the grinder of the second embodiment with the cover removed and the lever in the engaged position. [Figure 12] This is a partial cross-sectional view of the grinder according to the third embodiment when the lever is in the engaged position. [Figure 13] This is a perspective view of the cover. [Figure 14]It is an enlarged perspective view of the rail engaging portion and a peripheral portion thereof. [Figure 15] It is a partially exploded perspective view of the grinder with the end tool and the cover removed. [Figure 16] It is a partial cross-sectional view of the grinder when the lever is in the release position. [Figure 17] It is a partial perspective view of the grinder according to the fourth embodiment. [Figure 18] It is a perspective view of the cover. [Figure 19] It is a bottom view of the grinder when the lever is in the engagement position. [Figure 20] It is a partially exploded perspective view of the grinder with the end tool and the cover removed. [Figure 21] It is a bottom view of the grinder when the lever is in the release position. [Figure 22] It is a partial cross-sectional view of the grinder according to the fifth embodiment when the lever is in the engagement position. [Figure 23] It is a perspective view of the cover. [Figure 24] It is a cross-sectional view showing the lever and the rail in the engagement position. [Figure 25] It is a partial perspective view of the grinder. [Figure 26] It is a partially exploded perspective view of the grinder with the end tool and the cover removed. [Figure 27] It is a partial cross-sectional view of the grinder when the lever is in the release position. [Figure 28] It is a cross-sectional view showing the lever and the rail in the release position. [Figure 29] It is a partial cross-sectional view of the grinder according to the sixth embodiment when the lever is in the engagement position. [Figure 30] It is a partial perspective view of the grinder. [Figure 31] It is a partially exploded perspective view of the grinder with the end tool and the cover removed. [Figure 32] It is a cross-sectional view showing the lever and the rail in the engagement position. [Figure 33] This is a partial cross-sectional view of the grinder when the lever is in the release position. [Figure 34] This is a cross-sectional view showing the lever and rail in the release position. [Figure 35] This is a partial cross-sectional view of the grinder according to the seventh embodiment when the latch is in the engaged position. [Figure 36] This is a bottom view of the grinder when the latch is in the engaged position. [Figure 37] This is a cross-sectional view showing the latch and cover in the released position. [Figure 38] This is a bottom view of the grinder with a different cover attached. [Figure 39] This is a bottom view of the grinder with yet another cover attached. [Modes for carrying out the invention]

[0010] In one non-limiting embodiment of this disclosure, the first engaging portion may be configured as a projection that protrudes radially outward from the upper plate portion or outer peripheral portion of the cover body. This embodiment increases the design flexibility of the engagement structure between the first engaging portion and the second engaging portion.

[0011] In addition to or instead of the above embodiment, the second engaging portion may be a lever that is linearly movable substantially parallel to the drive shaft. According to this embodiment, the rotation of the cover body can be effectively restricted by the cooperation of a protrusion provided on the cover body and a movable member with a simple configuration provided on the housing.

[0012] In addition to or in lieu of the above embodiments, the protruding portion may have at least one recess or hole extending in the vertical direction. The second engaging portion may have a projection configured to engage with the recess or hole when in the engaged position. According to this embodiment, rotation of the cover body relative to the housing can be reliably restricted.

[0013] In addition to or in lieu of the above embodiments, the second engaging portion may be movable in a plane substantially perpendicular to the drive shaft. According to this embodiment, the second engaging portion can be reliably miniaturized in the vertical direction.

[0014] In addition to or in lieu of the above embodiments, the protruding portion may have at least one recess that is recessed radially inward from the outer edge of the protruding portion. The second engaging portion may have a projection configured to engage with the recess when in the engaged position. According to this embodiment, rotation of the cover body relative to the housing can be reliably restricted.

[0015] In addition to, or in place of, the above embodiment, the second engaging portion may be a rotatable lever that can be operated externally by the user. According to this embodiment, an easy-to-operate lever is realized.

[0016] In addition to the above embodiments, or in place of the above embodiments, a biasing member configured to bias the second engaging portion toward the engagement position may be further provided. According to this embodiment, the engagement state between the first engaging portion and the second engaging portion can be maintained by the biasing force of the biasing member.

[0017] In addition to the above embodiments, or in place of the above embodiments, the first engaging portion may be formed separately from the cover body and fixed to the cover body. According to this embodiment, since the cover body and the first engaging portion can be manufactured separately and then fixed to each other, manufacturing is easier compared to the case in which the cover body and the first engaging portion are formed integrally from the beginning.

[0018] In addition to the above embodiment, or in place of the above embodiment, the lower end of the second engaging portion may be at the same position as the lower end of the cover body, or above the lower end of the cover body, both when the second engaging portion is in the engaged position and when it is in the released position. According to this embodiment, since the second engaging portion does not protrude downward from the cover body, the entire power tool including the second engaging portion can be made smaller in the vertical direction. Furthermore, the possibility of the second engaging portion being affected by unexpected external forces can be reduced.

[0019] In addition to the above embodiments, or in place of the above embodiments, the second engaging portion may be located between the upper end and the lower end of the cover body in the vertical direction, whether the second engaging portion is in the engaged position or the released position. According to this embodiment, since the second engaging portion does not protrude above or below the cover body, the possibility of the second engaging portion being affected by unexpected external forces can be further reduced.

[0020] Hereinafter, with reference to the drawings, representative and non-limiting embodiments of this disclosure will be described in detail. In the following embodiments, a handheld electric disc grinder (hereinafter simply referred to as a grinder) will be given as an example of a power tool. A grinder is also an example of a rotary tool configured to rotate a cutting tool.

[0021] <First Embodiment> The grinder 1A according to the first embodiment will be described below with reference to Figures 1 to 10.

[0022] First, the general configuration of the grinder 1A will be described. As shown in Figures 1 and 2, the grinder 1A comprises a motor 21, a spindle 25 operably connected to the motor 21, and a housing 10A that houses the motor 21 and the spindle 25. The housing 10A is an elongated hollow body that forms the outer shell of the grinder 1A. The motor 21 is positioned such that the rotation axis RX of the output shaft 215 extends approximately parallel to the long axis of the housing 10A. The spindle 25 is located within one end of the housing 10A in the direction of its long axis. The spindle 25 is rotatably supported within the housing 10A around the drive axis DX. The drive axis DX intersects (more specifically, substantially orthogonal to) the rotation axis RX of the output shaft 215.

[0023] One axial end of the spindle 25 is exposed to the outside from the housing 10A. The tool tip 91 is removably attached to this end of the spindle 25. A portion of the tool tip 91 is covered by a cover 5A attached to the housing 10A.

[0024] As the spindle 25 is rotated around the drive shaft DX by the motor 21, the tip tool 91 rotates, performing machining operations on the workpiece. Various tip tools 91, such as grinding wheels, cutting wheels, blades, rubber pads, and brushes, are available for attachment to the grinder 1A. Grinding wheels, cutting wheels, and blades are not limited examples of disc-shaped tip tools 91. The user selects the appropriate tip tool 91 according to the desired machining operation and attaches it to the grinder 1A. The grinder 1A can perform machining operations such as grinding, polishing, and cutting on the workpiece, depending on the type of tip tool 91.

[0025] The detailed configuration of grinder 1A is described below. For the sake of clarity, the direction in which the drive shaft DX extends is defined as the vertical direction of grinder 1A. In the vertical direction, the side where the tip tool 91 is located is defined as the lower side of grinder 1A, and the opposite side is defined as the upper side of grinder 1A. The direction in which the rotation axis RX of the output shaft 215 extends is defined as the front-rear direction of grinder 1A. In the front-rear direction, the side where the spindle 25 is located is defined as the front side of grinder 1A, and the opposite side is defined as the rear side of grinder 1A. The direction perpendicular to the vertical and front-rear directions is defined as the left-right direction of grinder 1A. Furthermore, any direction perpendicular to the drive shaft DX is defined as the radial direction, the direction away from the drive shaft DX is defined as the radially outward direction, and the direction towards the drive shaft DX is defined as the radially inward direction.

[0026] First, let's explain the configuration of housing 10A.

[0027] As shown in Figures 1 and 2, the housing 10A includes, in order from front to back, a drive mechanism housing 11, a motor housing 13, a handle 15, and a controller housing 17. The drive mechanism housing 11 is the part that houses the spindle 25 and the intermediate shaft 23, and is also called the gear housing. The drive mechanism housing 11 constitutes the front end of the housing 10A. The motor housing 13 is the part that houses the motor 21 and the fan 22. The handle 15 is the part that is gripped by the user, and is also called the grip. The controller housing 17 is the part that houses the controller 29. The controller housing 17 constitutes the rear end of the housing 10A.

[0028] The elements (mechanisms) arranged within the housing 10A will be described below.

[0029] The output shaft 215 of the motor 21 is supported within the motor housing 13 so as to be rotatable around the rotation axis RX. The fan 22 is fixed to the portion of the output shaft 215 that extends forward of the stator 211 and rotates integrally with the output shaft 215.

[0030] As shown in Figure 3, the spindle 25 is rotatably supported around the drive shaft DX within the drive mechanism housing 11. A driven gear 250 is fixed around the upper part of the spindle 25. The lower end of the spindle 25 protrudes below the housing 10A. The lower end of the spindle 25 is configured as a tool mounting portion 253 from which a tip tool 91 can be attached and detached. In this embodiment, the outer circumferential surface of the tool mounting portion 253 is threaded, and the tip tool 91 is fixed to the tool mounting portion 253 by a lock nut 254. However, the method of attaching the tip tool 91 to the spindle 25 is not limited to this, and any known method may be adopted.

[0031] The grinder 1A is equipped with a cover 5A to protect the user from dust and sparks generated during the machining of the workpiece by the cutting tool 91. The cover 5A is removablely attached to the housing 10A and is configured to partially cover the cutting tool 91 attached to the tool mounting portion 253 of the spindle 25. The cover 5A is also referred to as a wheel cover, disc cover, protective cover, protective hood, etc. Details of the cover 5A will be described later.

[0032] As shown in Figure 3, the intermediate shaft 23 is a shaft that transmits the rotational driving force of the motor 21 to the spindle 25, and is operably connected to the motor 21 and the spindle 25. Specifically, the intermediate shaft 23 is arranged coaxially with the output shaft 215 of the motor 21 and is rotatably supported within the drive mechanism housing 11 around the rotation axis RX. The rear end of the intermediate shaft 23 engages with the front end of the output shaft 215 via a connecting member, and the intermediate shaft 23 rotates integrally with the output shaft 215. A drive gear 230 is provided at the front end of the intermediate shaft 23. The drive gear 230 meshes with a driven gear 250. Bevel gears are used for both the drive gear 230 and the driven gear 250.

[0033] With the above configuration, the spindle 25 rotates around the drive shaft DX via the intermediate shaft 23 in response to the drive of the motor 21, and the tip tool 91 fixed to the tool mounting section 253 rotates integrally with the spindle 25. However, the rotational driving force of the motor 21 may be transmitted to the spindle 25 via any mechanism other than the intermediate shaft 23.

[0034] As shown in Figure 2, a switch 27 is housed in the handle portion 15. The switch 27 is a switch for starting the motor 21. In this embodiment, while the switch is in the ON position, power is supplied to the motor 21, and the motor 21 is driven. The housing 10A is provided with a switch knob 271 for switching the switch 27 on and off. More specifically, the switch knob 271 is supported on the upper part of the motor housing portion 13 so as to be externally operable by the user and movable between the ON position and the OFF position. The switch knob 271 is normally held in the OFF position. The switch knob 271 is connected to the switch 27 via a connecting member 272. The switch 27 is switched from OFF to ON as the user moves the switch knob 271 from the OFF position to the ON position.

[0035] The controller housing 17 houses a controller 29 configured to control the operation of the grinder 1A. The controller 29 includes a control circuit and is electrically connected to the motor 21, switch 27, etc. In this embodiment, the controller 29 is configured to control the driving of the motor 21 (power supply to the motor 21) in accordance with the on / off state of the switch 27.

[0036] Furthermore, the controller housing 17 is provided with a battery mounting section 18. A rechargeable battery 93 is detachably mounted in the battery mounting section 18. The battery mounting section 18 includes a physical engagement structure with the battery 93 and terminals for electrically connecting to the battery 93. The grinder 1A of this embodiment operates on power supplied from the battery 93. However, the grinder 1A may be configured to operate on power supplied from an external AC power source via a power cord.

[0037] The cover 5A will be described below. Although the cover 5A is removable from the housing 10A, in the following description, the orientation of the cover 5A will be referred to based on the orientation of the grinder 1A when the cover 5A is attached to the housing 10A.

[0038] As shown in Figures 1, 3, and 4, the cover 5A comprises a cover body 50 and a rail 55A. The cover body 50 is a single (seamless) metal component. On the other hand, the rail 55A is originally a metal component formed separately from the cover body 50 and is fixed to the cover body 50. With this configuration, manufacturing is easy because the cover body 50 and the rail 55A can be processed separately and then joined together. However, the cover body 50 and the rail 55A may be a single component formed integrally.

[0039] The cover body 50 is configured to partially cover the tip tool 91. The cover body 50 in this embodiment includes an upper plate portion 51, an outer peripheral portion 53, and a lip portion 54.

[0040] The upper plate portion 51 is a thin, plate-like part positioned above the tip tool 91 in the vertical direction. The upper plate portion 51 is positioned substantially parallel to the plane perpendicular to the drive shaft DX (i.e., substantially parallel to the surface of the disc-shaped tip tool 91 (e.g., grinding wheel, cutting wheel, blade)). The upper plate portion 51 is also formed in a fan shape (arc shape) when viewed from above or below, and its inner edge (radially inner edge) 511 and outer edge (radially outer edge) 515 are arc-shaped. The upper plate portion 51 is configured to cover the portion of the disc-shaped tip tool 91 that is 180 degrees or more in angle.

[0041] The outer peripheral portion 53 is provided along the outer edge 515 of the upper plate portion 51 and is a portion that protrudes downward from the upper plate portion 51. The outer peripheral portion 53 is formed in the shape of a thin plate that is curved in an arc. The outer peripheral portion 53 is positioned radially outward of the tip tool 91 with respect to the outer edge of the disc-shaped tip tool 91. The lower end of the outer peripheral portion 53 is configured to be located at least below the lower surface of the disc-shaped tip tool 91.

[0042] The lip portion 54 is a part that protrudes radially inward from the lower end of the outer circumference portion 53. The inner edge of the lip portion 54 is radially outward from the outer edge of the disc-shaped tip tool 91. The radial width of the lip portion 54 may be changed, or the lip portion 54 may be omitted.

[0043] The rail 55A is a thin, plate-like portion that protrudes radially outward from the cover body 50. More specifically, the rail 55A protrudes radially outward from the upper end of the outer peripheral portion 53. The position of the rail 55A is set such that its upper surface 551 is substantially in the same plane as the upper surface 513 of the upper plate portion 51 (they are substantially in the same position in the vertical direction). The width (radial length) of the rail 55A is substantially uniform and is significantly smaller than the diameter of the upper plate portion 51. The thickness of the rail 55A in the vertical direction is substantially uniform. From this configuration, it can be said that the rail 55A is an arc-shaped projection that protrudes radially outward from the upper plate portion 51 or the outer peripheral portion 53.

[0044] Furthermore, the rail 55A has a plurality of engagement holes 56A arranged spaced apart from each other. In this embodiment, all engagement holes 56A are arranged at equal intervals, but the spacing between adjacent engagement holes 56A may differ. The engagement holes 56A are holes that penetrate the rail 55A in the vertical direction (in the thickness direction of the rail 55A). However, the engagement holes 56A may be recesses (bottomed holes) that are open downwards, or recesses (notches) that are recessed radially inward from the outer edge of the rail 55A. In this embodiment, the engagement holes 56A have a circular cross-section.

[0045] The following describes the structure provided in housing 10A for the installation of cover 5A.

[0046] As shown in Figures 1, 3, 5, and 6, the housing 10A is provided with a body engagement portion 31A configured to engage with the cover body 50 of the cover 5A (specifically, the upper plate portion 51), and a rail engagement portion 30A configured to engage with the rail 55A.

[0047] As shown in Figures 3, 5, and 6, the main body engagement portion 31A includes a main body engagement groove 311. The main body engagement groove 311 is an annular groove formed in the housing 10A so as to surround the drive shaft DX (spindle 25). The main body engagement groove 311 is configured to receive at least a portion of the inner edge portion 512 (the arc-shaped portion along the inner edge 511) of the upper plate portion 51 of the cover body 50. More specifically, the main body engagement groove 311 and the inner edge portion 512 are configured so that their respective cross-sectional shapes are substantially aligned with each other. The user can move the cover 5A, which is positioned so that the upper plate portion 51 is substantially perpendicular to the drive shaft DX and the inner edge portion 512 faces the main body engagement groove 311 from the front side of the housing 10A, backward relative to the housing 10A and fit the inner edge portion 512 into the main body engagement groove 311. Furthermore, with the inner edge 512 of the upper plate portion 51 fitted into the main body engagement groove 311, the user can rotate the cover 5A around the drive shaft DX relative to the housing 10A.

[0048] The rail engagement portion 30A includes a rail engagement groove 32A and a lever 35A.

[0049] As shown in Figures 3, 5, and 6, the rail engagement groove 32A is provided on the radially outer side of the cover 5A in the housing 10A. In this embodiment, the rail engagement groove 32A is provided behind the main body engagement groove 311 and approximately in the center of the housing 10A in the left-right direction. The rail engagement groove 32A is an arc-shaped groove that opens forward and recesses backward, and is configured to receive a part of the outer edge 556 (the arc-shaped portion along the outer edge 555) of the rail 55A. The rail engagement groove 32A and the outer edge 556 are configured so that their respective cross-sectional shapes are generally consistent with each other. As described above, since the upper surface 513 of the upper plate portion 51 of the cover body 50 and the upper surface 551 of the rail 55A are substantially in the same plane, the upper ends of the main body engagement groove 311 and the rail engagement groove 32A are substantially in the same position in the vertical direction.

[0050] The rail engagement groove 32A faces the portion of the main body engagement groove 311 located behind the spindle 25 in the front-rear direction. In the radial direction, the rail engagement groove 32A is configured such that the distance between the bottom surface (the inner side of the groove) of the main body engagement groove 311 and the bottom surface of the rail engagement groove 32A is slightly greater than the distance between the inner edge 511 of the upper plate portion 51 and the outer edge 555 of the rail 55A. Therefore, as described above, when the user rotates the cover 5A with the inner edge 512 of the upper plate portion 51 fitted into the main body engagement groove 311, the outer edge 556 of the rail 55A fits into the rail engagement groove 32A. In this state, the user can rotate the cover 5A to the desired position. The cover 5A rotates while sliding between the inner edge 512 of the upper plate portion 51 and the outer edge 556 of the rail 55A, respectively, in the main body engagement groove 311 and the rail engagement groove 32A.

[0051] As shown in Figures 1, 5, and 6, the lever 35A is provided on the radially outer side of the cover 5A in the housing 10A. In this embodiment, the lever 35A is located at the left rear end of the drive mechanism housing 11. The lever 35A is also supported so as to be movable in a linear manner. Part of the lever 35A is exposed to the outside of the housing 10A, and another part is located inside the housing 10A.

[0052] More specifically, as shown in Figures 1, 5 to 7, the lever 35A includes an operating portion 351A configured to be manually operated by the user, an engaging portion 353A that can engage with the rail 55A, and a connecting portion 355A that connects the operating portion 351A and the engaging portion 353A. In this embodiment, the operating portion 351A, the connecting portion 355A, and the engaging portion 353A are configured as a single (seamless) metal member. However, the lever 35A may be formed by connecting and fixing multiple members to each other.

[0053] The connecting portion 355A is a plate-like portion that extends in a straight line and extends in the vertical direction. The operating portion 351A protrudes from one end (upper end) of the connecting portion 355A in a direction intersecting the connecting portion 355A (forward). The engaging portion 353A protrudes from the other end (lower end) of the connecting portion 355A in a direction intersecting the connecting portion 355A (forward). The tip (front end) of the engaging portion 353A is provided with an engaging projection 354A that protrudes toward the operating portion 351A (upward). The engaging projection 354A is configured to engage with the engaging hole 56A of the rail 55A of the cover 5A. The width of the tip of the engaging projection 354A in the left-right direction is set to be slightly smaller than the diameter of the engaging hole 56A.

[0054] The lever 35A is supported such that the operating portion 351A is exposed above the housing 10A, the connecting portion 355A is at least partially located inside the housing 10A, the engaging portion 353A is exposed below the housing 10A, and the engaging projection 354A protrudes upward.

[0055] More specifically, as shown in Figures 6 and 7, a portion of the connecting portion 355A is slidably positioned substantially parallel to the drive shaft DX (i.e., substantially vertically) within a retaining groove 101A formed at the rear end of the drive mechanism housing 11. The retaining groove 101A is recessed to the right from the left side of the housing 10A (drive mechanism housing 11), with its upper and lower ends open. The upper and lower ends of the connecting portion 355A protrude above and below the retaining groove 101A, respectively. The operating portion 351A protrudes forward from the connecting portion 355A above the retaining groove 101A, and the engaging portion 353A protrudes forward from the connecting portion 355A below the retaining groove 101A. The retaining groove 101A is also covered from the left side by a cover portion 102A. In this way, by using the retaining groove 101A and the cover portion 102A to position a part of the lever 35A (the connecting portion 355A) inside the housing 10A, assembly is made easier. Furthermore, the possibility of the lever 35A being affected by unexpected external forces can be reduced.

[0056] In this embodiment, the lever 35A is biased upward by a biasing member 357A. More specifically, a spring receiving projection 356A is provided on the connecting portion 355A of the lever 35A. The spring receiving projection 356A protrudes rearward from the connecting portion 355A. On the other hand, a spring receiving recess 103A communicating with the retaining groove 101A is provided on the rear side of the retaining groove 101A of the housing 10A. The spring receiving projection 356A is located within the spring receiving recess 103A. The biasing member 357A is a compression coil spring and is located below the spring receiving projection 356A within the spring receiving recess 103A. Therefore, in the initial state when no external force is applied that opposes the biasing force of the biasing member 357A, the lever 35A is held in its uppermost position where the spring receiving projection 356A abuts against the surface defining the upper end of the spring receiving recess 103A.

[0057] When the lever 35A is in its uppermost position, the operating portion 351A of the lever 35A is positioned above the upper end of the retaining groove 101A. Also, the engaging projection 354A of the engaging portion 353A is positioned to engage with the engaging hole 56A of the rail 55A of the cover 5A. More specifically, in the circumferential direction around the drive shaft DX, the engaging projection 354A is positioned to correspond to one of the engaging holes 56A of the rail 55A, and when the lever 35A is in its uppermost position, as shown in Figure 8, the engaging projection 354A is inserted into the engaging hole 56A from below and engages with the engaging hole 56A. Furthermore, the biasing force of the biasing member 357A stably maintains the engaged state between the engaging projection 354A and the engaging hole 56A. In the following, the position in which the lever 35A can engage with the rail 55A (more specifically, the position in which the engaging projection 354A can engage with the engaging hole 56A) is also referred to as the engagement position of the lever 35A.

[0058] The engaging projection 354A and engaging hole 56A, having the configuration described above, ensure that when the lever 35A is in the engaged position and the engaging projection 354A and engaging hole 56A are engaged, the rotation of the cover 5A relative to the housing 10A is reliably restricted. Furthermore, the fitting of the rail 55A (outer edge portion 556) and the rail engaging groove 32A, having the configuration described above, restricts the vertical movement of the cover body 50 relative to the housing 10A. Similarly, since the upper plate portion 51 (inner edge portion 512) of the cover body 5A is also fitted into the body engaging groove 311, the vertical movement of the cover 5A is restricted at two positions separated in the front-rear direction. As a result, the vertical movement of the cover body 50 relative to the housing 10A is effectively restricted. Movement in the front-rear direction is also effectively restricted.

[0059] The lever 35A can be moved downward from the engagement position in response to manual operation by the user. Specifically, when the user presses the operating part 351A downward, as shown in Figures 9 and 10, the lever 35A moves downward against the biasing force of the biasing member 357A, and the engagement projection 354A of the engagement part 353A disengages from the engagement hole 56A of the rail 55A. In other words, the engagement between the engagement projection 354A and the engagement hole 56A is released. Hereinafter, the position in which the lever 35A cannot engage with the rail 55A (more specifically, the position in which the engagement projection 354A and the engagement hole 56A cannot engage) is also referred to as the release position of the lever 35A. With the lever 35A in the release position, the user can rotate the cover 5A around the drive shaft DX relative to the housing 10A to position it in a desired location or remove it from the housing 10A.

[0060] In this embodiment, since the operating portion 351A of the lever 35A is exposed above the housing 10A, the user can easily move the lever 35A from the engaged position to the released position. Furthermore, since the lever 35A is configured to move linearly in response to downward pressure on the operating portion 351A, operation is easier compared to a configuration in which the operating portion 351A is pulled.

[0061] As described above, according to the grinder 1A of this embodiment, the rail 55A provided on the cover body 50 works in cooperation with the rail engagement portion 30A (rail engagement groove 32A and lever 35A) of the housing 10A to restrict the circumferential movement of the cover body 50 relative to the housing 10A (rotation around the drive shaft DX) and movement in directions other than the circumferential direction (specifically, the vertical and longitudinal directions). In other words, the rail 55A can perform two functions: proper positioning of the cover body 50 relative to the housing 10A in the circumferential direction and suppression of play (looseness) in other directions. Therefore, compared to realizing these two functions with separate structures, it is possible to reduce the required space and simplify the structure. In this embodiment, since the upper surface 551 of the rail 55A and the upper surface 513 of the upper plate portion 51 are in the same plane, the upper surfaces 551 and 513 can also be used integrally to restrict the upward movement of the cover body 50 (suppression of vertical play).

[0062] Furthermore, the rail 55A is a protruding portion that extends radially outward from the cover body 50 and does not protrude above or below the cover body 50. In addition, the rail engagement groove 32A of the rail engagement portion 30A is located above the lower end of the cover body 50, and the lower end of the lever 35A is located above the lower end of the cover body 50 in both the engaged and released positions. As a result, the overall size of the grinder 1A (especially the front end of the grinder 1A) in the vertical direction is suppressed. Also, the rail 55A and the rail engagement portion 30A do not get in the way during machining work. Thus, in this embodiment, a grinder 1A that is easy to operate even in relatively narrow spaces is realized.

[0063] <Second Embodiment> The grinder 1B according to the second embodiment will be described below with reference to Figure 11. Note that the components of the grinder 1B in the second embodiment, excluding the housing 10B, are substantially the same as those of the grinder 1A in the first embodiment (including cases where the shape differs slightly). Furthermore, the majority of the housing 10B has substantially the same configuration as the housing 10A in the first embodiment. Therefore, in the following, components of the grinder 1B that are substantially the same as those of the grinder 1A will be given the same reference numerals, and their descriptions will be omitted or simplified, while the different components will be described primarily. This also applies to subsequent embodiments.

[0064] As shown in Figure 11, the housing 10B of the second embodiment includes the same main body engaging portion 31A as in the first embodiment and a rail engaging portion 30B that is different from that of the first embodiment. The other configurations of the housing 10B are substantially the same as those of the housing 10A of the first embodiment. The rail engaging portion 30B includes the same rail engaging groove 32A (see Figure 3) as in the first embodiment and a lever 35B that is different from the lever 35A (see Figure 7) of the first embodiment.

[0065] Lever 35B is configured such that its operating direction is opposite to that of lever 35A. More specifically, lever 35B includes an operating portion 351A configured to be manually operated by the user, an engaging portion 353B that can engage with an engaging hole 56A of rail 55A, and a connecting portion 355A that connects the operating portion 351A and the engaging portion 353B. A portion of the connecting portion 355A is held in a retaining groove 101A so as to be slidable in the vertical direction, as in the first embodiment. The operating portion 351A protrudes forward from the upper end of the connecting portion 355A above the retaining groove 101A. The engaging portion 353B protrudes forward from the lower end of the connecting portion 355A. The tip of the engaging portion 353B is provided with an engaging projection 354B that protrudes downward. That is, the engaging projection 354B protrudes in the opposite direction to the engaging projection 354A of the first embodiment. The width of the tip of the engaging projection 354B in the left-right direction is set to be slightly smaller than the diameter of the engaging hole 56A.

[0066] Furthermore, in this embodiment, the biasing member 357A is positioned above the spring receiving projection 356A within the spring receiving recess 103A. Therefore, the lever 35B is biased downward by the biasing member 357A. In the initial state, the lever 35B is held at its lowest position, where the spring receiving projection 356A abuts against the surface defining the lower end of the spring receiving recess 103A. When the lever 35B is at its lowest position, the engaging projection 354B can engage with the engaging hole 56A of the rail 55A. In other words, in this embodiment, the lowest position of the lever 35B corresponds to the engaged position of the lever 35B, and the release position of the lever 35B is set above the engaged position. Although not shown in the figures, the user can move the lever 35B upward to the release position by pulling the operating part 351A upward against the biasing force of the biasing member 357A.

[0067] In this embodiment as well, the rail 55A and the rail engagement portion 30B work together to perform two functions: proper circumferential positioning of the cover body 50 relative to the housing 10B, and suppression of play in other directions. Therefore, compared to realizing these two functions with separate structures, it is possible to reduce the required space and simplify the structure.

[0068] Furthermore, the rail 55A is a protruding portion that extends radially outward from the cover body 50 and does not protrude above or below the cover body 50. In addition, the lever 35B is located above the lower end of the cover body 50, both in the engaged and released positions. Therefore, in this embodiment as well, the overall vertical size of the grinder 1B (especially the front end of the grinder 1A) is suppressed, resulting in a grinder 1B that is easy to operate even in relatively confined spaces.

[0069] <Third Embodiment> The grinder 1C according to the third embodiment will be described below with reference to Figures 12 to 16. The grinder 1C includes a cover 5C and a housing 10C that differ in configuration from those of the first embodiment.

[0070] As shown in Figures 12 and 13, the cover 5C comprises a cover body 50 and a rail 55C. The rail 55C has substantially the same configuration as the rail 55A of the first embodiment (see Figure 4). That is, the rail 55C is an arc-shaped projection that protrudes radially outward from the cover body 50 and has a plurality of engagement holes 56A. However, unlike the first embodiment, the rail 55C protrudes from approximately the center of the outer circumference 53 in the vertical direction.

[0071] As shown in Figures 12, 14, and 15, the housing 10C has the same body engagement portion 31A (body engagement groove 311) as in the first embodiment and a rail engagement portion 30C that is different from that of the first embodiment. The other configurations of the housing 10C are substantially the same as those of the housing 10A of the first embodiment.

[0072] The rail engagement portion 30C is located behind the cover 5C and includes a lever 35C that differs from that of the first embodiment. The lever 35C is partially housed in the lower part of the housing 10C. The lever 35C is also configured to be operated from below by the user. More specifically, the lever 35C includes an operating portion 351C configured to be manually operated by the user, an engagement portion 353C that can engage with an engagement hole 56A of the rail 55C, and a connecting portion 355C that connects the operating portion 351A and the engagement portion 353B.

[0073] The connecting portion 355C is a plate-shaped portion that extends in a straight line. The connecting portion 355C is slidably positioned vertically within a retaining groove 101C formed at the lower end of the housing 10C. The retaining groove 101C is located approximately in the center of the housing 10C in the left-right direction. The operating portion 351C is connected to the lower end of the connecting portion 355C below the retaining groove 101C, forming a T-shape with the connecting portion 355C. The engaging portion 353C protrudes forward from the upper end of the connecting portion 355C, beyond the retaining groove 101C. The tip of the engaging portion 353C is provided with an engaging projection 354C that protrudes downward. The width of the tip of the engaging projection 354C in the left-right direction is set to be slightly smaller than the diameter of the engaging hole 56A.

[0074] The lever 35C is biased downward by a biasing member 357C. The biasing member 357C is located in a spring-receiving recess 103C provided in the housing 10C. The spring-receiving recess 103C communicates with the retaining groove 101C on the front side and is configured to recess upward. The engaging portion 353C of the lever 35C is located within the spring-receiving recess 103C. The spring-receiving recess 103C is covered from below by a cover portion 102C. By arranging a portion of the lever 35C within the housing 10C using the spring-receiving recess 103C and the cover portion 102C in this way, assembly is facilitated. Furthermore, the possibility of the lever 35C being affected by unexpected external forces can be reduced.

[0075] The biasing member 357C is a compression coil spring, positioned above the engaging portion 353C within the spring receiving recess 103C. Therefore, as shown in Figure 12, in the initial state, the lever 35C is held in its lowest position, with the engaging portion 353C in contact with the upper surface of the cover portion 102C. When the lever 35C is in its lowest position, the engaging projection 354C can engage with the engaging hole 56A of the rail 55C. In other words, in this embodiment, the lowest position of the lever 35C corresponds to the engaged position of the lever 35C, and the release position of the lever 35C is set above the engaged position. On the other hand, as shown in Figure 16, the user can move the lever 35C upward to the release position by pressing the operating portion 351C upward against the biasing force of the biasing member 357C.

[0076] As described above, in the grinder 1C of this embodiment, the rotation of the cover body 50 relative to the housing 10C is restricted by the engagement of the rail 55C provided on the cover body 50 and the lever 35C provided on the housing 10C. In this embodiment as well, the rotation of the cover body 50 relative to the housing 10C is reliably restricted by the engagement of the engaging projection 354C of the lever 35C and the engaging hole 56A of the rail 55C.

[0077] The rail 55C is a projection that extends radially outward from the cover body 50 and does not protrude above or below the cover body 50. In this embodiment, the lever 35C is located between the upper and lower ends of the cover body 50, both in the engaged and released positions. This suppresses an increase in the overall vertical size of the grinder 1A (especially the front end of the grinder 1A). Furthermore, the rail 55C and lever 35C do not get in the way during machining operations. Thus, in this embodiment as well, a grinder 1C that is easy to operate even in relatively confined spaces is realized.

[0078] <Fourth Embodiment> The grinder 1D according to the fourth embodiment will be described below with reference to Figures 17 to 21. The grinder 1D includes a cover 5D and a housing 10D that differ in configuration from those of the first embodiment.

[0079] As shown in Figures 17 and 18, the cover 5D comprises a cover body 50 and a rail 55D. The rail 55D is configured as an arc-shaped projection that protrudes radially outward, similar to the rail 55A in the first embodiment (see Figure 4). On the other hand, unlike the rail 55A, the rail 55D protrudes from approximately the center in the vertical direction of the outer circumference 53. The rail 55D also has a plurality of engagement recesses 56D formed on its outer edge. The engagement recesses 56D are rectangular recesses (notches) that are recessed radially inward from the outer edge of the rail 55D. In this embodiment, all engagement recesses 56D are arranged at equal intervals, but the spacing between adjacent engagement recesses 56D may differ.

[0080] As shown in Figures 17, 19, and 20, the housing 10D includes the same body engagement portion 31A (body engagement groove 311) as in the first embodiment, and a rail engagement portion 30D that is different from that of the first embodiment. The other configurations of the housing 10D are substantially the same as those of the housing 10A of the first embodiment.

[0081] The rail engagement portion 30D is located behind the cover 5D and includes a lever 35D that differs from that of the first embodiment. The lever 35D is a rotatable lever and is supported at the lower end of the housing 10D behind the cover 5D. The lever 35D is also configured to be operated by a user from the side of the housing 10D. More specifically, the lever 35D includes an operating portion 351D configured to be manually operated by a user, an engagement portion 353D that can engage with an engagement recess 56D of the rail 55D, and a connecting portion 355D that connects the operating portion 351D and the engagement portion 353D.

[0082] The connecting portion 355D is a plate-shaped portion that extends in a straight line. The connecting portion 355D is rotatably attached to a cylindrical portion 105 provided at the lower end of the housing 10D via a screw 358D, and extends generally in the left-right direction. The operating portion 351D is connected to the left end of the connecting portion 355D on the left side of the housing 10D. The operating portion 351D is formed in an L-shape and includes a tab that protrudes to the left. The engaging portion 353D includes an engaging projection 354D that protrudes downward from the right end of the connecting portion 355D. The engaging projection 354D is located approximately in the center of the housing 10D in the left-right direction. The width of the tip of the engaging projection 354D in the left-right direction is set to be slightly smaller than the width of the engaging recess 56D in the circumferential direction.

[0083] In this embodiment, the lever 35D is rotationally biased by a biasing member 357D in a direction in which the engaging projection 354D moves forward (i.e., closer to the cover 5D). More specifically, the biasing member 357D is a torsion coil spring. The coil portion of the biasing member 357D is arranged around a cylindrical portion 105 into which a screw 358D is threaded. A spring receiving projection 356D is provided in the portion of the connecting portion 355D of the lever 35D between the screw 358D and the engaging projection 354D, projecting upward. One end of the biasing member 357D is locked to the housing 10D, and the other end is locked to the spring receiving projection 356D. As a result, the lever 35D is rotationally biased around an axis extending in the vertical direction, in a direction in which the engaging projection 354D moves forward.

[0084] In the circumferential direction, the engaging projection 354D is positioned to correspond to one of the engaging recesses 56D, and when the lever 35D is in its foremost position, as shown in Figure 19, the engaging projection 354D is inserted into the engaging recess 56D from the radially outward direction. In other words, in this embodiment, the position of the lever 35D when the engaging projection 354D is in its foremost position corresponds to the engagement position of the lever 35D. On the other hand, as shown in Figure 21, when the user presses the operating part 351D (tab) forward, the lever 35D rotates around an axis extending in the vertical direction, against the biasing force of the biasing member 357D, in a direction that moves the engaging projection 354D backward (i.e., away from the cover 5D). As a result, the lever 35D moves to a release position where the engaging projection 354D is disengaged from the engaging recess 56D of the rail 55D.

[0085] As described above, in the grinder 1D of this embodiment, the rotation of the cover body 50 relative to the housing 10D is restricted by the engagement of the rail 55D provided on the cover body 50 and the lever 35D provided on the housing 10D. In this embodiment as well, the rotation of the cover body 50 relative to the housing 10D is reliably restricted by the engagement of the engaging projection 354D of the lever 35D and the engaging recess (notch) 56D of the rail 55D.

[0086] The rail 55D is a projection that extends radially outward from the cover body 50 and does not protrude above or below the cover body 50. In this embodiment, the lever 35D is a rotating lever that moves in a plane substantially perpendicular to the drive shaft DX, and is located between the upper and lower ends of the cover body 50 in both the engaged and disengaged positions. As a result, the overall size of the grinder 1A (especially the front end of the grinder 1A) in the vertical direction is suppressed. In addition, the rail 55D and lever 35D do not get in the way during machining work. Thus, in this embodiment as well, a grinder 1D that is easy to operate even in relatively narrow spaces is realized. <Fifth Embodiment> The grinder 1E according to the fifth embodiment will be described below with reference to Figures 22 to 28. The grinder 1E includes a cover 5E and a housing 10E that differ in configuration from those of the first embodiment.

[0087] As shown in Figures 22 and 23, the cover 5E comprises a cover body 50 and a rail 55E. The rail 55E is configured as an arc-shaped projection that protrudes radially outward, similar to the rail 55A in the first embodiment. The upper surface 551 of the rail 55E is substantially in the same plane as the upper surface 513 of the upper plate portion 51. On the other hand, unlike the first embodiment, the rail 55E has a plurality of engagement recesses 56E formed on its upper surface 551. The engagement recesses 56E are hemispherical recesses that are recessed downward from the upper surface 551. In this embodiment, all engagement recesses 56E are arranged at equal intervals, but the spacing between adjacent engagement recesses 56E may differ.

[0088] As shown in Figures 22, 24 to 26, the housing 10E includes the same body engagement portion 31A (body engagement groove 311) as in the first embodiment, and a rail engagement portion 30E that is different from that of the first embodiment. The other configurations of the housing 10E are substantially the same as those of the housing 10A of the first embodiment.

[0089] The rail engagement portion 30E is located behind the cover 5E and includes an engagement projection 32E (see Figures 24 and 26), a regulating wall 33, and a lever 35E.

[0090] The engaging projection 32E protrudes downward from the portion of the lower surface 104 of the central part of the housing 10E in the left-right direction, specifically from the part located directly above the rail 55E of the cover 5E. The engaging projection 32E is configured to generally align with the engaging recess 56E of the rail 55E. In other words, the engaging projection 32E is a hemispherical projection.

[0091] The restricting wall 33 is a wall portion that extends vertically behind the engaging projection 32E. The front surface of the restricting wall 33 is gently curved to correspond to the outer edge 555 of the rail 55E. The restricting wall 33 is configured such that, in the radial direction, the distance between the bottom surface (the inner surface of the groove) of the main engaging groove 311 and the front surface of the restricting wall 33 is slightly greater than the distance between the inner edge 511 of the upper plate portion 51 and the outer edge 555 of the rail 55E.

[0092] The lever 35E is a rotatable lever supported at the lower end of the housing 10E, behind the cover 5E. The lever 35E is also configured to be operated by the user from below the housing 10E. More specifically, the lever 35E is generally L-shaped when viewed from the side. The lever 35E includes an operating portion 351E configured to be manually operated by the user, an engaging portion 353E configured to engage (contact) with the rail 55E, and a connecting portion 355E connecting the operating portion 351E and the engaging portion 353E.

[0093] A pair of left and right arm portions 356E protrude from the connecting portion 355E. The connecting portion 355E is rotatably attached to the lower end of the housing 10E via a support pin 358E. The support pin 358E is inserted through the arm portion 356E and is supported by a pair of left and right support portions 107 provided on the housing 10E, extending in the left-right direction. Therefore, the lever 35E is rotatable around an axis extending in the left-right direction. The operating portion 351E extends generally rearward from one end of the connecting portion 355E below the housing 10E. The engaging portion 353E extends generally upward from the other end of the connecting portion 355E. In this embodiment, the engaging portion 353E is configured to engage (contact) with the rail 55E and press the rail 55E against the housing 10E (lower surface 104).

[0094] In this embodiment, the lever 35E is biased by a biasing member 357E to rotate in a direction in which the engaging portion 353E moves generally upward (i.e., approaches the rail 55E from below). More specifically, the biasing member 357E is a torsion coil spring. The coil portion of the biasing member 357E is arranged around the support pin 358E. One end of the biasing member 357E is locked to the housing 10E, and the other end is locked to the connecting portion 355E. As a result, the lever 35E is biased to rotate around an axis extending in the left-right direction, in a direction in which the engaging portion 353E moves generally upward.

[0095] As shown in Figure 22, when the engaging portion 353E is in its uppermost position, the tip of the engaging portion 353E abuts against the lower surface 552 of the rail 55E of the cover 5E, pressing the rail 55E against the lower surface 104 of the housing 10E. In the circumferential direction, when the engaging projection 32E on the lower surface of the housing 10E is positioned to correspond to one of the engaging recesses 56E, the engaging projection 32E fits into the engaging recess 56E, as shown in Figure 24. Hereinafter, the position of the lever 35E when the engaging portion 353E engages (abuts against) the rail 55E and presses against the housing 10E, and engages the engaging projection 32E with the engaging recess 56E, will also be referred to as the engagement position of the lever 35E. When the lever 35E is in the engagement position, the operating portion 351D extends diagonally downward as it moves towards the rear.

[0096] As shown in Figures 27 and 28, when the user presses the operating part 351E upward, that is, towards the housing 10E, the lever 35E rotates against the biasing force of the biasing member 357E, in a direction that causes the engaging part 353E to move downward (that is, away from the rail 55E). This releases the engagement between the engaging projection 32E and the engaging recess 56E. Hereinafter, the position of the lever 35E when the engaging projection 32E and the engaging recess 56E are not engaged will also be referred to as the release position of the lever 35E. With the lever 35E in the release position, the user can rotate the cover 5E around the drive shaft DX relative to the housing 10E to position it in a desired location or remove it from the housing 10E.

[0097] As shown in Figures 22 and 27, in this embodiment, whether the lever 35E is in the engaged position or the released position, the rear end of the operating section 351E (the tip of the lever 35E) is positioned at least forward of the handle section 15 (see Figure 1) in the front-to-back direction. In this embodiment, the rear end of the operating section 351E is positioned forward of the switch knob 271 supported by the motor housing section 13. More specifically, the rear end of the operating section 351E is located directly below the front end of the motor housing section 13 (more specifically, directly below the fan 22). This arrangement makes it less likely for the lever 35E to get in the way when the user grips the handle section 15 and operates the switch knob 271.

[0098] As described above, in the grinder 1E of this embodiment, the rail 55E and the rail engagement portion 30E work together to perform two functions: proper circumferential positioning of the cover body 50 relative to the housing 10E, and suppression of play in other directions. Therefore, compared to realizing these two functions with separate structures, it is possible to reduce the required space and simplify the structure.

[0099] Specifically, the lever 35E, biased by the biasing member 357E, presses the rail 55E against the lower surface 104 of the housing 10E, thereby effectively restricting the vertical movement of the rail 55E relative to the housing 10E. In this embodiment, since the upper surface 551 of the rail 55E and the upper surface 513 of the upper plate portion 51 are in the same plane, the upper surfaces 551 and 513 are pressed together against the lower surface 104 of the housing 10E, thereby more reliably restricting the vertical movement of the cover 5E.

[0100] Furthermore, in this embodiment, the lever 35E engages with the hemispherical engaging projection 32E of the housing 10E and the engaging recess 56E of the rail 55E, and the lever 35E presses the rail 55E against the lower surface 104 of the housing 10E. This effectively suppresses the movement of the cover 5E in all directions relative to the housing 10E (e.g., circumferential, longitudinal, and vertical movement). The engaging projection 32E may be omitted. Even in this case, the lever 35E pressing the rail 55E against the lower surface 104 of the housing 10E can restrict not only the vertical movement of the cover 5E relative to the housing 10E, but also movement in other directions (e.g., circumferential and longitudinal movement). In addition, the restricting wall 33 can effectively restrict the longitudinal movement of the cover 5E.

[0101] <Sixth Embodiment> The grinder 1F according to the sixth embodiment will be described below with reference to Figures 29 to 34. The grinder 1F includes a cover 5F and a housing 10F, which have partially different configurations from those of the first embodiment.

[0102] As shown in Figures 29 and 30, the cover 5F comprises a cover body 50 and a rail 55F. The rail 55F is configured as an arc-shaped projection that protrudes radially outward, similar to the rail 55A of the first embodiment (see Figure 4). However, unlike the first embodiment, the upper surface 551 of the rail 55F is located below the upper surface 513 of the upper plate portion 51 of the cover body 50. The rail 55F also has a plurality of engagement holes 56F, similar to the first embodiment. In this embodiment, all engagement holes 56F are arranged at equal intervals, but the spacing between adjacent engagement holes 56F may differ.

[0103] As shown in Figures 29 to 32, the housing 10F includes the same main body engagement portion 31A (main body engagement groove 311) and rail engagement portion 30F as in the first embodiment. The other configurations of the housing 10F are substantially the same as those of the housing 10A in the first embodiment.

[0104] The rail engagement portion 30F is located behind the cover 5F and includes a rail engagement groove 32F and a lever 35F.

[0105] The rail engagement groove 32F is located behind the main engagement groove 311 and approximately in the center of the housing 10F in the left-right direction. The rail engagement groove 32F is located below the main engagement groove 311, corresponding to the rail 55F being located below the upper plate portion 51. The rail engagement groove 32F has substantially the same configuration as the rail engagement groove 32A of the first embodiment (see Figure 3). That is, the rail engagement groove 32F is a groove that opens forward, recesses backward, and extends in an arc shape, and is configured to receive a part of the outer edge portion 556 of the rail 55F. The rail engagement groove 32F and the outer edge portion 556 are configured so that their respective cross-sectional shapes are generally consistent with each other.

[0106] Lever 35F differs from lever 35E (see Figure 26) of the fifth embodiment only in that it has an engaging portion 353F instead of the engaging portion 353E of lever 35E; otherwise, it has a substantially identical configuration to lever 35E. In other words, lever 35F is formed in a roughly L-shape when viewed from the side and includes an operating portion 351E, an engaging portion 353F, and a connecting portion 355E that connects the operating portion 351E and the engaging portion 353F.

[0107] Lever 35F, like lever 35E, is supported at the rear of cover 5F and at the lower end of housing 10F via support pin 358E, and is rotatable about an axis extending in the left-right direction. In this embodiment, lever 35F is located to the right of rail engagement groove 32F. Engaging portion 353F has an engaging projection 354F at its tip. The engaging projection 354F is configured to engage with the engagement hole 56F of rail 55F. The left-right width of the tip of the engaging projection 354F is set to be slightly smaller than the diameter of the engagement hole 56F. Similar to the fifth embodiment, lever 35F is biased by biasing member 357E to rotate in a direction in which the engaging projection 354F of engaging portion 353F moves generally upward (i.e., approaches rail 55F from below).

[0108] As shown in Figures 30 and 32, in the circumferential direction, the engaging projection 354F is positioned to correspond to one of the engaging holes 56F. When the engaging projection 354F is in its uppermost position, the engaging projection 354F is inserted into the engaging hole 56F from below and engages with the engaging hole 56F. In other words, in this embodiment, the position of the lever 35F when the engaging projection 354F is in its uppermost position corresponds to the engagement position of the lever 35F.

[0109] As shown in Figures 33 and 34, when the user presses the operating part 351E upward, that is, towards the housing 10F, the lever 35F rotates around an axis extending in the left-right direction, against the biasing force of the biasing member 357E, so that the engaging projection 354F moves downward, and is positioned in the release position. In this embodiment, since the engaging projection 354F moves in an arc shape within the engaging hole 56F as the lever 35F rotates, the diameter of the engaging hole 56F is set to be larger than that of the engaging hole 56A in the first embodiment.

[0110] In the grinder 1F of this embodiment, similar to the first embodiment, the rail 55F and the rail engagement portion 30F (rail engagement groove 32F and lever 35F) work together to perform two functions: proper circumferential positioning of the cover body 50 relative to the housing 10F, and suppression of play in other directions. Therefore, compared to realizing these two functions with separate structures, it is possible to reduce the required space and simplify the structure.

[0111] <Seventh Embodiment> The grinder 1G according to the seventh embodiment will be described below with reference to Figures 35 to 37. The grinder 1G comprises a cover 5G and a housing 10G that differ in configuration from the first embodiment. The cover 5G comprises only the cover body 50. In other words, the cover 5G does not have rails. The housing 10G comprises the same body engagement portion 31A (body engagement groove 311) as the first embodiment and an outer peripheral engagement portion 30G that is not present in the first embodiment. In Figure 35, for convenience, the housing 10G of the grinder 1G and some of the mechanisms arranged inside the housing 10G are simply illustrated or omitted from the illustration, but the configuration of the grinder 1G other than the outer peripheral engagement portion 30G is substantially the same as that of the grinder 1A of the first embodiment (see Figure 3).

[0112] As shown in Figures 35 to 37, the outer peripheral engaging portion 30G includes a latch 35G positioned below the housing 10G. The latch 35G is a tension-operated fastener and may also be called a draw latch or toggle latch. The latch 35G includes a rectangular metal plate-shaped engaging portion 353G and a U-shaped metal arm 355G. One longitudinal end of the engaging portion 353G is bent to form a hook 354G. Both ends of the arm 355G are rotatably connected to both sides of the other longitudinal end of the engaging portion 353G. The central part of the arm 355G is rotatably supported around an axis extending in the left-right direction at the lower end of the housing 10G.

[0113] With the above configuration, the latch 35G is movable between an engaged position in which the hook 354G engages with the lip portion 54, as shown in Figures 35 and 36, and a released position in which the hook 354G cannot engage with the lip portion 54, as shown in Figure 37. When the latch 35G is in the engaged position, tension acts on the cover 5G via the engaging portion 353G, restricting the circumferential movement of the cover 5G relative to the housing 10G (rotation around the drive shaft DX). Since the size of the latch 35G in the vertical direction can be minimized when it is in the engaged position, it can contribute to miniaturization of the grinder 1G in the vertical direction (extending direction of the drive shaft DX).

[0114] Below, with reference to Figures 38 and 39, two more examples of covers that can effectively accommodate latch 35G are shown.

[0115] The cover 5H shown in Figure 38 has a plurality of projections 541 that protrude radially inward from the lip portion 54. The projections 541 are arranged at equal intervals in the circumferential direction. The spacing between adjacent projections 541 is set to be slightly larger than the width in the left-right direction of the engaging portion 353G of the latch 35G. With this configuration, when the latch 35G is in the engaged position, the hook 354G (see Figure 35) engages with the lip portion 54 between the projections 541, thereby more reliably restricting the rotation of the cover 5H relative to the housing 10G.

[0116] The cover 5J shown in Figure 39 has a lip portion 54 on its outer circumference 53, but instead of having a lip portion 54, the outer circumference 53 (circumferential wall portion) has a plurality of protrusions 535 that project radially inward. The protrusions 535 are arranged at equal intervals in the circumferential direction. The spacing between adjacent protrusions 535 is set to be slightly larger than the width in the left-right direction of the engaging portion 353G of the latch 35G. With this configuration, as in the example in Figure 38, when the latch 35G is in the engaged position, the hook 354G engages with the lower end of the outer circumference 53 between the protrusions 535, thereby more reliably restricting the rotation of the cover 5J relative to the housing 10G.

[0117] The correspondence between each component (feature) of the above embodiments and each component (feature) of the present disclosure or invention is shown below. However, each component of the embodiments is merely an example and does not limit each component of the present disclosure or invention.

[0118] Grinders 1A, 1B, 1C, 1D, 1E, and 1F are examples of "power tools". Spindle 25 is an example of a "spindle". Housings 10A, 10B, 10C, 10D, 10E, and 10F are examples of "housings". Cover body 50 is an example of a "cover body". Top plate 51 and outer perimeter 53 are examples of "top plate" and "outer perimeter", respectively. Rails 55A, 55C, 55D, 55E, and 55F are examples of "first engaging parts" and also examples of "protruding parts". Lever 35A, 35B, 35C, 35D, 35E, and 35F are examples of "second engaging parts".

[0119] Lever 35A, 35B, and 35C are examples of "linearly movable levers". Engagement holes 56A and 56F are examples of "holes in protruding parts". Lever 35D is an example of a "rotatable lever" that can move in a plane substantially perpendicular to the drive shaft. Engagement recess 56D is an example of a "recess in a protruding part". Engagement projections 354A, 354B, 354C, 354D, and 354F are examples of "projections in second engaging parts". Biasing members 357A, 357C, 357D, and 357E are examples of "biasing members".

[0120] The above embodiments are merely illustrative, and the power tools relating to this disclosure are not limited to the illustrated grinders 1A, 1B, 1C, 1D, 1E, and 1F. For example, modifications as illustrated below can be made. Furthermore, at least one of these modifications may be adopted in combination with the grinders 1A, 1B, 1C, 1D, 1E, and 1F illustrated in the embodiments, and at least one of the features described in each claim.

[0121] For example, this disclosure may also be applied to other types of power tools (e.g., cutters, circular saws, multi-tools) that have a removable cover that partially covers the tip tool mounted on the spindle. Depending on the type of power tool, the configuration of the housing, the elements (mechanisms) housed in the housing, and their arrangement may be modified as appropriate.

[0122] The cover body relating to this disclosure is not limited to the cover body 50 exemplified in the above embodiment. For example, the shape of the cover body 50 (e.g., the circumferential length and radial length of the upper plate portion 51) can be changed as appropriate.

[0123] The first engaging portion according to this disclosure is not limited to the rails 55A, 55C, 55D, 55E, and 55F exemplified in the above embodiments. For example, the shape of the rails 55A, 55C, 55D, 55E, and 55F (e.g., circumferential length, radial width, vertical thickness, etc.) and / or the position of the rails 55A, 55C, 55D, 55E, and 55F relative to the cover body 50 can be changed as appropriate. The cross-sectional shape, size, and arrangement of the engaging holes 56A, 56F and engaging recesses 56E can also be changed as appropriate. Furthermore, the first engaging portion according to this disclosure does not necessarily have to be an arc-shaped rail, as long as it can engage with a second engaging portion (e.g., a lever) provided on the housing so as to be movable between an engaged position and a released position. For example, the first engaging portion may be configured as a projection, recess, or hole provided on the outer circumference of the cover body. Furthermore, the first engaging portion according to this disclosure may protrude from the top plate portion rather than the outer circumference portion.

[0124] The second engaging portion according to this disclosure is not limited to the levers 35A, 35B, 35C, 35D, 35E, and 35F exemplified in the above embodiments. For example, the configuration (e.g., shape, arrangement, and support configuration) of the levers 35A, 35B, 35C, 35D, 35E, and 35F can be appropriately changed in relation to the configuration of the first engaging portion (e.g., recesses or holes provided in the rails 55A, 55C, 55D, 55E, and 55F). For example, the second engaging portion may employ a lever that can move linearly in a plane perpendicular to the drive shaft DX between the engaged position and the released position. Furthermore, while it is preferable that the second engaging portion is biased to the engaged position by a biasing member, it may also be lockable to the housing in both the engaged and released positions. The springs used in the biasing members 357A, 357C, 357D, and 357E in the above embodiments are merely examples and may be changed to other types of springs or elastic bodies other than springs.

[0125] Furthermore, for example, the cross-sectional shape and arrangement of the rail engagement grooves 32A and 32F can be appropriately changed in accordance with changes to the first engagement portion (e.g., the rail). The rail engagement grooves 32A and 32F may be omitted. Alternatively, the housing may be provided with a configuration that restricts the movement of the cover body relative to the housing in directions other than the circumferential direction by engaging with the cover body instead of the first engagement portion (e.g., the rail).

[0126] In view of the spirit of the present invention and the embodiments described above, the following embodiments can be constructed. At least one of the following embodiments may be adopted in combination with the features of the embodiments and their modifications, or at least one of the features described in each claim. [Aspect 1] The first engaging portion is an arc-shaped rail. [Aspect 2] The housing has a rail engagement groove into which the outer edge of the rail can be fitted. [Aspect 3] The second engaging portion is at least partially housed in the housing. [Aspect 4] The aforementioned lever is A control unit configured to be operated externally by the user, The engagement portion is configured to engage with the first engagement portion when the lever is in the engagement position, and to be unable to engage with the second engagement portion when the lever is in the release position. It includes a connecting portion that connects the operating portion and the engaging portion. [Aspect 5] The operating unit is configured to be operated externally from above the housing. [Aspect 6] The operating unit is configured to be operated externally from the side of the housing. [Aspect 7] The upper plate portion is fan-shaped or arc-shaped, The outer periphery is a plate-like portion that is curved in an arc shape. [Aspect 8] The housing has a body engagement groove into which the inner edge of the upper plate portion of the cover body can be fitted. [Explanation of Symbols]

[0127] 1A, 1B, 1C, 1D, 1E, 1F, 1G: Grinder, 10A, 10B, 10C, 10D, 10E, 10F, 10G: Housing, 101A, 101C: Retaining groove, 102A, 102C: Cover part, 103A, 103C: Spring receiving recess, 104: Bottom surface, 105: Cylindrical part, 107: Support part, 11: Drive mechanism housing part, 13: Motor housing part, 15: Handle part, 17: Controller housing part, 18: Battery mounting part, 21: Motor, 211: Stator, 215: Output shaft 22: Fan, 23: Intermediate shaft, 230: Drive gear, 25: Spindle, 250: Driven gear, 253: Tool mounting part, 254: Lock nut, 27: Switch, 271: Switch knob, 272: Connecting member, 29: Controller, 30A, 30B, 30C, 30D, 30E, 30F, 30G: Outer circumference engaging part, 31A: Main body engaging part, 311: Main body engaging groove, 32A, 32F: Rail engaging groove, 32E: Engaging projection, 33: Regulating wall, 35A, 35B, 35C, 35D, 35 E, 35F: Lever, 351A, 351C, 351D, 351E: Operating part, 353A, 353B, 353C, 353D, 353E, 353F, 353G: Engaging part, 354A, 354B, 354C, 354D, 354F: Engaging projection, 354G: Hook, 355A, 355C, 355D, 355E: Connecting part, 355G: Arm, 356A, 356D: Spring receiving projection, 356E: Arm part, 357A, 357C, 357D, 357E: Biasing member, 358D: Screw, 358E :Support pin, 35G:Latch, 5A, 5C, 5D, 5E, 5F, 5G, 5H, 5J:Cover, 50:Cover body, 51:Top plate, 511:Inner edge, 512:Inner edge, 513:Top surface, 515:Outer edge, 53:Peripheral part, 535:Convex part, 54:Lip part, 541:Protrusion, 55A, 55C, 55D, 55E, 55F:Rail, 551:Top surface, 552:Bottom surface, 555:Outer edge, 556:Outer edge, 56A, 56F:Engagement hole, 56D, 56E:Engagement recess, 91:Tip tool, 93:Battery

Claims

1. It is a power tool, A spindle extending along a drive shaft that defines the vertical direction of the power tool, the spindle having a lower end from which a tip tool can be attached and detached, With the lower end exposed to the outside, the housing accommodates the spindle, A cover body that is removably attached to the housing and configured to partially cover the tip tool mounted on the lower end of the spindle, the cover body including an upper plate portion positioned above the tip tool and an outer peripheral portion that protrudes downward from the outer edge along the outer edge of the upper plate portion, The first engaging portion provided on the cover body, The housing is provided with a second engaging portion which is movable between an engaging position that engages with the first engaging portion and a disengaged position that cannot engage with the first engaging portion, The first engaging portion and the second engaging portion are configured to engage with each other, thereby restricting the rotation of the cover body around the drive shaft relative to the housing. The first engaging portion is located in the radial direction perpendicular to the drive shaft at the same position as the outer circumference or radially outward from the outer circumference, and is located between the upper and lower ends of the cover body in the vertical direction. The power tool is characterized in that the first engaging portion is configured as a protruding portion that protrudes radially outward from the upper plate portion or the outer peripheral portion of the cover body.

2. The power tool according to claim 1, The power tool is characterized in that the second engaging portion is a lever that can move linearly substantially parallel to the drive shaft.

3. The power tool according to claim 1, The aforementioned protrusion has at least one recess or hole extending in the vertical direction, The power tool is characterized in that the second engaging portion has a projection configured to engage with the recess or the hole when in the engaging position.

4. The power tool according to claim 1, The power tool is characterized in that the second engaging portion is movable in a plane substantially perpendicular to the drive shaft.

5. The power tool according to claim 4, The aforementioned protrusion has at least one recess that is recessed radially inward from the outer edge of the protrusion, The power tool is characterized in that the second engaging portion has a projection configured to engage with the recess when in the engaging position.

6. The power tool according to claim 4, The power tool is characterized in that the second engaging portion is a rotatable lever that can be operated externally by the user.

7. The power tool according to claim 1, The power tool further comprises a biasing member configured to bias the second engagement portion toward the engagement position.

8. The power tool according to claim 1, The power tool is characterized in that the first engaging portion is formed separately from the cover body and fixed to the cover body.

9. The power tool according to claim 1, The power tool is characterized in that the lower end of the second engaging portion is at the same position as the lower end of the cover body in the vertical direction, or above the lower end of the cover body, whether the second engaging portion is in the engaged position or in the released position.

10. The power tool according to claim 9, The power tool is characterized in that all of the second engaging portions are located between the upper end and the lower end of the cover body in the vertical direction, whether the second engaging portion is in the engaged position or in the released position.

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