Power tool and hammer drill

Abstract

To provide a power tool to which both of two kinds of different auxiliary handles can be attached exchangeably.SOLUTION: A power tool 1 includes: a main handle 5 integrated with a tool body 2; a columnar handle attaching part 10 capable of detachably mounting a first auxiliary handle 20 or a second auxiliary handle as an auxiliary handle to the tool body 2; and grooves 13, 14 formed on the outer peripheral surface of the handle attaching part 10 and extending in an axial direction. The first auxiliary handle 20 includes: a columnar first band 21; a band holding part 22 holding both ends of the first band 21 so as to rise and sink and changing the diameter of the first band 21; and a first projection projecting inwards in a diameter direction from the inner peripheral surface of the band holding part 22 and engaged with the grooves 13, 14. The second auxiliary handle includes: a columnar second band having a notch in an axial direction; a fastening member adjusting the width in a circumferential direction of the notch of the second band and changing the diameter of the second band; and a second projection projecting inwards in the diameter direction from the inner peripheral surface of the second band and engaged with the grooves 13, 14.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to power tools and hammer drills that can be fitted with auxiliary handles. [Background technology]

[0002] For example, a power tool known as a hammer drill has a tool body equipped with an electric motor as a power source, and a main handle that is integral with the tool body. A tip tool such as a hammer bit is attached to the front end of the tool body. A handle attachment part to which an auxiliary handle can be attached is provided in the front part of the tool body close to the attachment part of the tip tool. A user can hold the power tool in a stable position by holding both the main handle at the rear of the tool body and the auxiliary handle attached to the front part.

[0003] Patent Document 1 discloses an auxiliary handle equipped with a resin band. The resin band is provided in a generally C-shape with a cylindrical shape partially cut out in the axial direction. Both circumferential ends of the resin band are connected by a bolt. The circumferential ends of the resin band approach each other by rotating the bolt in the tightening direction. This allows the resin band to be reduced in diameter and attached to the handle attachment part. By rotating the bolt in the loosening direction, the distance between both circumferential ends of the resin band increases. This allows the resin band to be expanded in diameter and removed from the handle attachment part.

[0004] In addition to the power tool described in Patent Document 1, a power tool to which an auxiliary handle with an iron band can be attached has been provided. Both longitudinal ends of the iron band are held by a band holding part. The band holding part holds the iron band so that the protruding length of both ends can be changed. By shortening the protruding length of both ends of the iron band, the iron band can be elastically contracted in diameter and attached to the handle attachment part. By lengthening the protruding length of both ends of the iron band, the iron band can be expanded in diameter and removed from the handle attachment part.

[0005] In conventional products, the handle attachment part to which the iron band can be attached is provided with a smaller diameter than the front area of ​​the handle attachment part. The iron band is prevented from slipping off from the handle attachment part by utilizing the step caused by the difference in diameter. On the other hand, the resin band has a smaller elastic deformation amount than the iron band. Therefore, if a resin band is attached to a handle attachment part to which the iron band can be attached, it is difficult for the resin band to overcome the step of the anti-slip part provided at the front end of the handle attachment part even if the resin band is elastically deformed. Therefore, it is difficult to remove the resin band from the handle attachment part. Also, if an iron band is attached to the handle attachment part described in Patent Document 1, the iron band is not sufficiently prevented from slipping off from the handle attachment part. Thus, there has been no power tool in the past in which both an auxiliary handle with a resin band and an auxiliary handle with an iron band can be interchangeably attached. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5997660 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, there is a need for a power tool that can be interchangeably equipped with two different types of auxiliary handles. [Means for solving the problem]

[0008] According to one feature of the present disclosure, the power tool has a main handle that is integrally provided on the tool body. The power tool has a cylindrical handle attachment part that is provided on the tool body so that a first auxiliary handle or a second auxiliary handle can be detachably attached as an auxiliary handle. The power tool has a groove that is formed on the outer circumferential surface of the handle attachment part and extends in the axial direction. The first auxiliary handle has an arc-shaped first band. The first auxiliary handle has a band holding part that holds both ends of the first band in a retractable manner and changes the diameter of the first band. The first auxiliary handle has a first protrusion that protrudes radially inward from the inner circumferential surface of the first band and / or the band holding part and engages with the groove. The second auxiliary handle has an arc-shaped second band that has a notch in the axial direction. The second auxiliary handle has a fastening member that adjusts the circumferential width of the notch of the second band to change the diameter of the second band. The second auxiliary handle has a second protrusion that protrudes radially inward from the inner circumferential surface of the second band and engages with the groove.

[0009] Therefore, the groove provided in the handle attachment portion serves as both an engagement portion for the first protrusion of the first auxiliary handle and an engagement portion for the second protrusion of the second auxiliary handle. The first auxiliary handle is prevented from rotating relative to the handle attachment portion by engagement between the groove and the first protrusion. The second auxiliary handle is prevented from rotating relative to the handle attachment portion by engagement between the groove and the second protrusion. Therefore, the handle attachment portion can be interchangeably attached with a first auxiliary handle equipped with a first band that can be made to contract or expand in diameter by changing the length at which both ends protrude, and a second auxiliary handle equipped with a second band that can be made to contract or expand in diameter by adjusting the circumferential width of the notch. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of a power tool according to an embodiment of the present disclosure, the view showing a state in which a first auxiliary handle is attached. [Diagram 2] FIG. 2 is a perspective view of a power tool having a second auxiliary handle attached thereto. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. 4 is a left side view of the handle attachment portion to which the first auxiliary handle is attached. [Figure 6] 11 is a left side view of the handle attachment portion to which the second auxiliary handle is attached. FIG. [Figure 7] FIG. [Figure 8] 8 is a cross-sectional view taken along line VIII-VIII in FIG. 4. [Figure 9] FIG. 2 is a perspective view of a first auxiliary handle. [Figure 10] FIG. 4 is a front view of the first auxiliary handle. [Figure 11] FIG. 4 is a vertical cross-sectional view of the first auxiliary handle. [Figure 12] FIG. 13 is a top view of the first auxiliary handle with the first band removed. [Figure 13] FIG. 4 is a perspective view of a second auxiliary handle. [Figure 14] FIG. 4 is a front view of the second auxiliary handle. [Figure 15] 15 is a cross-sectional view taken along line XV-XV in FIG. 14. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] According to another feature of the present disclosure, the tool body has a shape in which the diameter of the area ahead of the handle attachment portion is the same as or smaller than the diameter of the handle attachment portion. Therefore, the area ahead of the handle attachment portion is prevented from interfering with the first band or the second band when the expanded first band or the second band is moved axially. Therefore, even if the amount of elastic deformation of the first band or the second band is small and the amount of expansion is small, the first band or the second band can be easily moved to a position radially outward of the handle attachment portion.

[0012] According to another feature of the present disclosure, the handle attachment portion has a fastening surface that abuts against an inner peripheral surface of the first band or an inner peripheral surface of the second band. The handle attachment portion has a retaining portion that is located at an axial end of the groove and protrudes from the groove. The retaining portion restricts axial movement of the first protrusion and the second protrusion. The retaining portion has the same radial height as the fastening surface or a radial height lower than the fastening surface.

[0013] Therefore, when the first band is fastened to the fastening surface, the retaining portion abuts against the first protrusion to prevent the first band from slipping out. When the second band is fastened to the fastening surface, the retaining portion abuts against the second protrusion to prevent the second band from slipping out. The first band or the second band is expanded in diameter from a reduced diameter state fastened to the fastening surface and moved in the axial direction. At this time, the first band or the second band moves toward the retaining portion having a radial height equal to or lower than the fastening surface. Therefore, interference between the first band or the second band and the retaining portion is suppressed. Thus, both the first band and the second band can be reliably prevented from slipping out when attached to the handle attachment portion, and can be smoothly removed when removed from the handle attachment portion.

[0014] According to another feature of the present disclosure, the groove is axially longer than the axial width of the first projection and is axially longer than the axial width of the second projection. Therefore, the first projection or the second projection can be securely accommodated in the groove in the axial direction. Therefore, the first band or the second band can be securely prevented from rotating or coming off the handle attachment portion.

[0015] According to another feature of the present disclosure, when the first auxiliary handle is attached to the handle attachment part, the axial position of the first protrusion of the first band relative to the groove is the same as the axial position of the second protrusion of the second band relative to the groove when the second auxiliary handle is attached to the handle attachment part. Therefore, the first auxiliary handle and the second auxiliary handle can be attached to the handle attachment part at the same axial position. Therefore, the same feeling of use can be achieved when the first auxiliary handle is attached and when the second auxiliary handle is attached. This increases the freedom of selection of the auxiliary handle to be attached to the handle attachment part, improving the usability of the power tool.

[0016] According to another feature of the present disclosure, the first projection is provided on an axial edge of the first band and / or the band holding portion. The second projection is provided on an axial edge of the second band. Thus, the first projection can be provided at a position abutting the axial edge of the groove. The second projection can be provided at a position abutting the axial edge of the groove. Thus, the same groove can function as a retainer for both the first projection and the second projection.

[0017] According to another feature of the present disclosure, the handle attachment portion is provided with a plurality of grooves in the circumferential direction. Therefore, the first band or the second band is prevented from rotating or coming off at a plurality of points in the circumferential direction of the handle attachment portion. Therefore, the position retention and attitude retention of the first band or the second band attached to the handle attachment portion can be improved.

[0018] According to another feature of the present disclosure, two of the grooves are provided at positions facing each other in the radial direction of the handle attachment part. Therefore, the first band or the second band can be positioned at the two positions that are furthest apart in the radial direction of the handle attachment part. This can further improve the position retention of the first band or the second band attached to the handle attachment part.

[0019] According to another feature of the present disclosure, four or more grooves are provided at equal intervals in the circumferential direction of the handle attachment part, so that the first auxiliary handle or the second auxiliary handle can be attached to the handle attachment part in a plurality of positions rotated at predetermined angular intervals (e.g., 90° intervals) in the circumferential direction.

[0020] According to another feature of the present disclosure, the power tool is a hammer drill equipped with a first auxiliary handle or a second auxiliary handle. Therefore, by a user gripping the first auxiliary handle or the second auxiliary handle attached to the handle attachment part, the user can hold the tool body in a stable position against the repeated striking motions of the hammer drill. Moreover, by switching between the first auxiliary handle and the second auxiliary handle depending on the usage state of the hammer drill, operability can be improved.

[0021] Next, one embodiment of the present disclosure will be described with reference to Figs. 1 to 15. A hammer drill is shown as an example of a power tool 1. The hammer drill can perform chipping or drilling on a workpiece such as concrete by repeatedly striking a tip tool such as a hammer bit. As shown in Fig. 1, the power tool 1 has a tool body 2 in which an electric motor 6 is housed, a chuck 4 provided at the front of the tool body 2 and capable of mounting a tip tool, and a main handle 5 that can be held by a user. The tool body 2 is provided in a long, approximately cylindrical shape along the axial direction of the electric motor 6. The main handle 5 extends approximately perpendicular to the longitudinal direction of the tool body 2 on the side opposite to the chuck 4. In the following description, the chuck 4 side is referred to as the front side, and the side on which the main handle 5 is provided is referred to as the rear side. The direction in which the main handle 5 extends relative to the tool body 2 is referred to as the down side. The left-right direction is based on the viewpoint of a user holding the main handle 5.

[0022] As shown in FIG. 1, the tool body 2 has a motor housing 2b in which an electric motor 6 is housed. The main handle 5 extends downward from the rear end of the motor housing 2b. The tool body 2 has a gear housing 2c in front of the motor housing 2b. The front region of the gear housing 2c is provided as a substantially cylindrical tip portion 2a whose axial direction is the front-rear direction. A cylindrical chuck 4 whose axial direction is the front-rear direction is provided in front of the tip portion 2a. The chuck 4 has a diameter smaller than that of the tip portion 2a. A tool insertion hole 4a extending in the front-rear direction is provided in the center of the chuck 4. The tip tool is attached to the output shaft 7 (see FIG. 8) located inside the gear housing 2c and the tip portion 2a by inserting the base of a tip tool such as a hammer bit into the tool insertion hole 4a from the front. A substantially cylindrical chuck cover 3 is provided on the outer periphery of the rear portion of the chuck 4. The chuck cover 3 has a diameter smaller than that of the tip portion 2a. The tool tip can be removed from the output shaft 7 by pulling the chuck cover 3 backward.

[0023] As shown in FIG. 1, the gear housing 2c accommodates a rotation transmission mechanism, a motion conversion mechanism, an impact mechanism, an output shaft 7 (see FIG. 8), etc. that are driven by the activation of the electric motor 6. The rotation transmission mechanism transmits the rotational power of the electric motor 6 to the output shaft 7 while reducing the speed. This causes the output shaft 7 to rotate around an axis extending in the front-rear direction. The motion conversion mechanism converts the rotational power of the electric motor 6 into linear back-rear reciprocating motion of a piston. The impact mechanism reciprocates the output shaft 7 in the front-rear direction using the power of the piston of the motion conversion mechanism. The tool attached to the output shaft 7 rotates around the axis and reciprocates in the front-rear direction, thereby repeatedly rotating and impacting the workpiece in front.

[0024] As shown in FIG. 1, a power cord 5c extending downward is provided at the lower end of the main handle 5. For example, by connecting the power cord 5c to a 100V AC power source, power can be supplied to the electric motor 6. A trigger 5a is provided on the front of the main handle 5. A user can hook the fingers holding the main handle 5 on the trigger 5a and pull it. Pulling the trigger 5a starts the electric motor 6. A lock button 5b that can be switched on and off by pressing is provided on the side of the main handle 5 and behind the trigger 5a. When the lock button 5b is in the off state, the electric motor 6 stops when the pulling operation of the trigger 5a is stopped. When the lock button 5b is in the on state, once the trigger 5a is pulled, the electric motor 6 continues to start even after the pulling operation is stopped. A forward / reverse switching lever 2d that can switch the rotation direction of the electric motor 6 between forward and reverse is provided on the side of the motor housing 2b and above the trigger 5a.

[0025] As shown in Fig. 3, the tip 2a of the tool body 2 is provided with a handle attachment part 10 to which an auxiliary handle can be removably attached. A first auxiliary handle 20 (see Fig. 1) having a first band 21 and a second auxiliary handle 30 (see Fig. 2) having a second band 31 can be interchangeably attached to the handle attachment part 10. Details of the first auxiliary handle 20 and the second auxiliary handle 30 will be described later. The handle attachment part 10 has a cylindrical fastening surface 12 and an annular retaining part 11 provided in front of the fastening surface 12. The fastening surface 12 and the retaining part 11 are provided so as to have the same radial height from the shaft center. The front end of the fastening surface 12 and the rear end of the retaining part 11 are connected to be flush with each other.

[0026] As shown in Figs. 3, 4, 7, and 8, grooves 13 and 14 extending in the axial direction (front-rear direction) are provided on the outer peripheral surface of the handle attachment part 10. The groove 13 is recessed radially inward with respect to the fastening surface 12. The groove 13 has a trapezoidal cross section when viewed from the front-rear direction. The groove 14 is provided in a flat shape by cutting out the fastening surface 12 in a direction perpendicular to the radial direction. The grooves 13 and 14 are provided at 45° intervals in the circumferential direction around the axial center C. Specifically, two grooves 14 are provided, one each at the upper end (this position is defined as the 0° position) and the lower end (180° position) of the fastening surface 12. A total of six grooves 13 are provided at positions of 45°, 90°, 135°, 225°, 270°, and 315° at 45° intervals between the two grooves 14. The front ends 13a, 14a of the grooves 13, 14 are provided at the same front-to-rear position as the rear end of the retaining portion 11. Therefore, the retaining portion 11 protrudes radially outward from the front ends 13a, 14a of the grooves 13, 14. The rear ends 13b, 14b of the grooves 13, 14 are provided at approximately the same front-to-rear position as the rear end of the fastening surface 12.

[0027] As shown in Figs. 3, 4 and 7, the tip 2a of the tool body 2 is provided with a cup attachment portion 15 to which a separately prepared, substantially cylindrical dust-collecting cup can be attached. The cup attachment portion 15 is provided in front of the retaining portion 11. The cup attachment portion 15 is provided in a substantially cylindrical shape with a diameter equal to or smaller than that of the retaining portion 11. The cup attachment portion 15 is provided with a plurality of L-shaped grooves, each of which is made up of a groove extending in the axial direction and a groove extending in the circumferential direction. The dust-collecting cup is inserted from the front to the rear of the cup attachment portion 15 and rotated in the circumferential direction relative to the cup attachment portion 15. This allows the dust-collecting cup to be attached so as to cover the chuck 4 and the tool bit from the radially outward direction.

[0028] As shown in Figs. 1, 9 to 11, the first auxiliary handle 20 has a first band 21 curved in an arc shape, a band holding portion 22 that holds both ends of the first band 21, and a grip 24 connected to the band holding portion 22. The first band 21 is made of iron, which has high elasticity and rigidity, and is provided with a substantially constant thickness. The first band 21 is provided above the band holding portion 22. The grip 24 extends in a cylindrical shape in the up-down direction below the band holding portion 22. The surface of the grip 24 is covered with an elastomer resin layer to prevent slipping when the user holds it. Note that, for convenience of explanation, the up-down, left-right, and right-left directions of the first auxiliary handle 20 are specified, but the position of the first auxiliary handle 20 relative to the power tool 1 is not limited thereto. For example, the grip 24 may extend in a direction such as left, right, upward, diagonally downward left, diagonally upward left, diagonally downward right, or diagonally upward right relative to the handle mounting portion 10.

[0029] 9, a disk-shaped flange 24a extending in a direction perpendicular to the up-down direction is provided at the upper end of grip 24. A disk-shaped flange 22c extending in a direction perpendicular to the up-down direction and capable of sliding on the upper surface of flange 24a is provided at the lower end of band holding part 22. Grip 24 can be rotated relative to band holding part 22 around a screw shaft 26b of band connecting member 26 described later.

[0030] As shown in Figs. 9 to 12, an opening 22a that opens upward is provided at the top of the band holding part 22. The opening 22a is arc-shaped when viewed from the front-rear direction and rectangular when viewed from above. First projections 23 that protrude radially inward are provided on the inner peripheral surfaces of the front wall 22f and the rear wall 22g that constitute the opening 22a. The front wall 22f and the rear wall 22g correspond to the axial (front-rear) edges of the band holding part 22. The first projections 23 have substantially the same shape as the cross-sectional shape of the groove 13 (see Fig. 8) so as to fit into the groove 13, and are provided in a trapezoidal shape when viewed from the front-rear direction. Three first projections 23 are provided on each of the front wall 22f and the rear wall 22g of the opening 22a at 45° intervals in the circumferential direction around the axial center C of the handle attachment part 10 (see Fig. 8). The multiple first protrusions 23a provided on the front wall 22f of the opening 22a and the multiple first protrusions 23b provided on the rear wall of the opening 22a are disposed so as to overlap with each other when viewed from the front-rear direction.

[0031] As shown in Figs. 11 and 12, the first auxiliary handle 20 is provided with a fastening mechanism 25 that changes the length of the first band 21 relative to the opening 22a to fasten the first band 21 to the fastening surface 12 (see Fig. 1). A rectangular box-shaped recess 22b that opens upward is provided on the inner lower side of the opening 22a. A band connecting member 26 of the fastening mechanism 25 is provided inside the box-shaped recess 22b. The band connecting member 26 is movable in the vertical direction along the wall surface of the box-shaped recess 22b. A pair of rectangular columnar insertion parts 26a that protrude toward both the left and right are provided on the upper part of the band connecting member 26. A rectangular insertion hole 21e that penetrates the first band 21 in the plate thickness direction is provided on both longitudinal end parts 21d of the first band 21. The insertion part 26a is inserted into the insertion hole 21e of the longitudinal end part 21d. As a result, the first band 21 extends and retracts in the vertical direction relative to the opening 22a in conjunction with the up and down movement of the band connecting member 26. The diameter of the first band 21 increases or decreases according to the change in the length of extension and retraction. When the first band 21 is in a reduced diameter state, the inner peripheral surface 21a of the first band 21 becomes an arcuate surface following the arcuate shape of the opening 22a.

[0032] 11, a circular through hole 22d is provided at the bottom end of the box-shaped recess 22b, vertically penetrating the band holding portion 22. A band connecting member 26 extending in the vertical direction is inserted into the through hole 22d and protrudes towards the grip 24. A threaded shaft portion 26b having a male thread is provided at the bottom of the band connecting member 26.

[0033] As shown in FIG. 11, a circular through hole 24b is provided in the center of the grip 24, penetrating in the vertical direction. A hexagonal nut engagement recess 24c is provided in communication with the lower end of the through hole 24b. A hexagonal nut 25a screwed onto the threaded shaft portion 26b is inserted into the nut engagement recess 24c. The hexagonal nut 25a is prevented from rotating relative to the grip 24 by the nut engagement recess 24c. When the grip 24 is rotated around the axis of the threaded shaft portion 26b, the hexagonal nut 25a also rotates around the axis of the threaded shaft portion 26b. As a result, the threaded shaft portion 26b screwed onto the hexagonal nut 25a moves in the vertical direction relative to the hexagonal nut 25a. When the threaded shaft portion 26b moves upward, the first band 21 becomes longer in projection length and expands in diameter. When the threaded shaft portion 26b moves downward, the first band 21 becomes shorter in projection length and contracts in diameter.

[0034] 5, the front end 21b of the first band 21 is provided at approximately the same front-to-rear position as the front end of the front first protrusion 23a. The rear end 21c of the first band 21 is provided at approximately the same front-to-rear position as the rear end of the rear first protrusion 23b. The grooves 13, 14 are provided longer in the axial direction (front-to-rear direction) than the width from the front end of the front first protrusion 23a to the rear end of the rear first protrusion 23b.

[0035] As shown in FIG. 5, the first band 21 in an expanded state is moved backward from the front of the tool body 2 to a radially outer position of the fastening surface 12 to reduce the diameter. As a result, the inner peripheral surface 21a (see FIG. 10) of the first band 21 is fastened following the fastening surface 12. When the first band 21 is fastened to the fastening surface 12, the front end 21b of the first band 21 and the front first protrusion 23a are located rearward of the front ends 13a and 14a of the grooves 13 and 14. When the first band 21 is fastened to the fastening surface 12, the rear end 21c of the first band 21 and the rear first protrusion 23b are located forward of the rear ends 13b and 14b of the grooves 13 and 14. As a result, the multiple first protrusions 23a and 23b are all accommodated in the grooves 13 and 14 and fitted into the groove 13 or engaged with the groove 14.

[0036] As shown in Figs. 1 and 11, the band holding part 22 is provided with a hexagonal pole insertion hole 22e that penetrates in the front-rear direction so that a hammer pole prepared separately can be inserted therethrough. The hammer pole is used when repeatedly forming holes of a predetermined depth in a workpiece. A pushable unlock button 27 is provided below the pole insertion hole 22e of the band holding part 22. The unlock button 27 is biased downward by a compression spring 27b. A pole engagement part 27a having rack teeth arranged in the front-rear direction is provided on the upper part of the unlock button 27. When the unlock button 27 is not pressed, the rack teeth of the pole engagement part 27a advance to the right part of the pole insertion hole 22e. As a result, the rack teeth of the pole engagement part 27a engage with the rack teeth of the hammer pole inserted into the pole insertion hole 22e. The hammer pole is locked at a front-rear position where it protrudes forward by a predetermined protruding length. When the unlock button 27 is pressed upward against the biasing force, The rack teeth of the pole engaging portion 27a are retracted from the pole insertion hole 22e, whereby the rack teeth of the pole engaging portion 27a are disengaged from the rack teeth of the hammer pole, allowing the hammer pole to be moved in the front-rear direction.

[0037] As shown in Figs. 2, 13 to 15, the second auxiliary handle 30 has a second band 31 having a substantially C-shape with a part of the cylindrical shape cut out in the axial direction, and a grip 34 connected to the second band 31. The second band 31 is made of a resin having a relatively high elasticity and a relatively high rigidity. The inner peripheral surface 31a of the second band 31 is arc-shaped when viewed from the front-rear direction. The grip 34 extends in a cylindrical shape in the vertical direction below the second band 31. The surface of the grip 34 is covered with an elastomer resin layer to prevent slipping when the user holds it. The upper end of the grip 34 is provided with a disk-shaped flange 34a extending in a direction perpendicular to the vertical direction. Although the vertical, horizontal, and lateral directions of the second auxiliary handle 30 are specified for the convenience of explanation, the position of the second auxiliary handle 30 relative to the power tool 1 is not limited thereto. For example, the grip 34 may be in a position extending leftward, rightward, upward, diagonally downward to the left, diagonally upward to the left, diagonally downward to the right, diagonally upward to the right, etc. relative to the handle attachment portion 10 .

[0038] As shown in Figs. 13 to 15, the inner peripheral surface 31a of the second band 31 is provided with a second protrusion 32 protruding radially inward. The second protrusion 32 has a shape substantially the same as the cross-sectional shape of the groove 13 (see Fig. 8) so as to fit into the groove 13, and is provided in a trapezoidal shape when viewed from the front-rear direction. A total of eight second protrusions 32 are provided at 45° intervals in the circumferential direction around the axial center C of the handle attachment part 10 (see Fig. 8). The front end 32a of the second protrusion 32 is provided near the front end (edge) 31b of the second band 31 and is located slightly rearward of the front end 31b. The rear end 32b of the second protrusion 32 is provided near the rear end (edge) 31c of the second band 31 and is located slightly forward of the rear end 31c.

[0039] As shown in Figs. 13 and 14, the second auxiliary handle 30 is provided with a fastening member 33 for expanding or contracting the diameter of the second band 31. The fastening member 33 has a bolt 33b, an operating portion 33a that can rotate the bolt 33b around its axis, and a hexagonal nut 33c that is screwed onto the bolt 33b. The second band 31 has a circumferential end portion 31d on the base side and a circumferential end portion 31e on the tip side that is in a cantilever state. The circumferential ends 31d, 31e face each other in the circumferential direction. The circumferential ends 31d, 31e are connected in the circumferential direction by a bolt 33b that is screwed onto each of them. The operating portion 33a is rotatably provided on the base side (left side) of the second band 31 including the circumferential end portion 31d. The hexagonal nut 33c is screwed onto the bolt 33b while being prevented from rotating within the right circumferential end portion 31e.

[0040] As shown in Figs. 13 and 14, a notch 31f is formed by cutting the arc shape of the second band 31 in the axial direction between the circumferential ends 31d and 31e. When the operating portion 33a of the fastening member 33 is rotated in the fastening direction, the hexagonal nut 33c in the circumferential end 31e moves leftward relative to the bolt 33b. As a result, the circumferential ends 31d and 31e approach each other, and the circumferential width of the notch 31f, in other words, the circumferential distance between the circumferential end 31d and the circumferential end 31e, becomes narrower. Therefore, the diameter of the second band 31 is reduced. When the operating portion 33a of the fastening member 33 is rotated in the loosening direction, the hexagonal nut 33c in the circumferential end 31e moves rightward relative to the bolt 33b. As a result, the circumferential ends 31d and 31e move away from each other, and the circumferential width of the notch 31f increases. Therefore, the diameter of the second band 31 increases.

[0041] As shown in FIG. 6, the second band 31 in an expanded state is moved backward from the front of the tool body 2 to a radially outer position of the fastening surface 12 to reduce the diameter. As a result, the inner peripheral surface 31a (see FIG. 13) of the second band 31 is fastened following the fastening surface 12. The grooves 13 and 14 are provided longer in the axial direction (front-rear direction) than the width from the front end 32a to the rear end 32b of the second projection 32. Therefore, when the second band 31 is fastened to the fastening surface 12, the front end 32a of the second projection 32 is located rearward of the front ends 13a and 14a of the grooves 13 and 14. When the second band 31 is fastened to the fastening surface 12, the rear end 32b of the second projection 32 is located forward of the rear ends 13b and 14b of the grooves 13 and 14. As a result, the multiple second projections 32 are all accommodated in the grooves 13 and 14 and fitted into the grooves 13 or engaged with the grooves 14.

[0042] As described above, the power tool 1 has a main handle 5 that is integrally provided on the tool body 2 as shown in Figs. 1 and 2. The power tool 1 has a cylindrical handle attachment portion 10 that is provided on the tool body 2 to which a first auxiliary handle 20 or a second auxiliary handle 30 can be detachably attached as an auxiliary handle. The power tool 1 has grooves 13, 14 that are formed on the outer circumferential surface of the handle attachment portion 10 and extend in the axial direction. The first auxiliary handle 20 has a first band 21 that is arc-shaped. The first auxiliary handle 20 has a band holding portion 22 that holds both ends (longitudinal ends 21d, see Fig. 11) of the first band 21 in a retractable manner to change the diameter of the first band 21. The first auxiliary handle 20 has a first protrusion 23 that protrudes radially inward from the inner circumferential surface (front wall 22f and rear wall 22g) of the band holding portion 22 and engages with the grooves 13, 14 (see Fig. 9). The second auxiliary handle 30 has an arc-shaped second band 31 having a notch 31f in the axial direction. The second auxiliary handle 30 has a fastening member 33 that adjusts the circumferential width of the notch 31f of the second band 31 to change the diameter of the second band 31. The second auxiliary handle 30 has a second protrusion 32 that protrudes radially inward from the inner circumferential surface 31a of the second band 31 and engages with the grooves 13, 14 (see FIG. 13).

[0043] Therefore, the grooves 13, 14 provided in the handle attachment part 10 serve as an engagement part for the first protrusion 23 of the first auxiliary handle 20 and an engagement part for the second protrusion 32 of the second auxiliary handle 30. The first auxiliary handle 20 is prevented from rotating relative to the handle attachment part 10 by the engagement of the grooves 13, 14 with the first protrusion 23. The second auxiliary handle 30 is prevented from rotating relative to the handle attachment part 10 by the engagement of the grooves 13, 14 with the second protrusion 32. Therefore, the first auxiliary handle 20 having the first band 21 that can be reduced or expanded in diameter by changing the protruding length of both longitudinal ends 21d, and the second auxiliary handle 30 having the second band 31 that can be reduced or expanded in diameter by adjusting the circumferential width of the notch 31f can be interchangeably attached to the handle attachment part 10.

[0044] 3, 4 and 7, the tool body 2 has a shape in which the diameter ahead of the handle mounting part 10 is the same as or smaller than the diameter of the handle mounting part 10. Therefore, in the area ahead of the handle mounting part 10, interference with the first band 21 or the second band 31 is suppressed when the expanded first band 21 or the second band 31 is moved axially. Therefore, even if the amount of elastic deformation of the first band 21 or the second band 31 is small and the amount of expansion is small, the first band 21 or the second band 31 can be easily moved to a position radially outward of the handle mounting part 10.

[0045] As shown in Figures 3 to 7, the handle attachment part 10 has a fastening surface 12 that abuts against the inner circumferential surface 21a of the first band 21 (see Figure 9) or the inner circumferential surface 31a of the second band 31 (see Figure 13). The handle attachment part 10 has a retaining portion 11 that is located at the axial end of the grooves 13, 14 and protrudes from the grooves 13, 14. The retaining portion 11 restricts the axial movement of the first projection 23 and the second projection 32. The retaining portion 11 has the same radial height as the fastening surface 12 or a lower radial height than the fastening surface 12.

[0046] Therefore, when the first band 21 is fastened to the fastening surface 12, the retaining portion 11 abuts against the first protrusion 23 to prevent the first band 21 from slipping out. When the second band 31 is fastened to the fastening surface 12, the retaining portion 11 abuts against the second protrusion 32 to prevent the second band 31 from slipping out. The first band 21 or the second band 31 is expanded in diameter from the reduced diameter state fastened to the fastening surface 12 and moved in the axial direction. At this time, the first band 21 or the second band 31 moves toward the retaining portion 11 having the same radial height as the fastening surface 12 or a lower radial height than the fastening surface 12. Therefore, interference between the first band 21 or the second band 31 and the retaining portion 11 is suppressed. Thus, both the first band 21 and the second band 31 can be reliably prevented from slipping out when attached to the handle attachment portion 10, and can be smoothly removed from the handle attachment portion 10.

[0047] 5 and 6, the grooves 13, 14 are axially longer than the axial width of the first projection 23 (the width from the front end of the first projection 23a to the rear end of the first projection 23b) and are also axially longer than the axial width of the second projection 32. Therefore, the first projection 23 or the second projection 32 can be securely accommodated in the grooves 13, 14 in the axial direction. Therefore, the first band 21 or the second band 31 can be securely prevented from rotating or coming off the handle attachment portion 10.

[0048] 5 and 6, when the first auxiliary handle 20 is attached to the handle attachment portion 10, the axial position of the first protrusion 23 of the first band 21 relative to the grooves 13, 14 is the same as the axial position of the second protrusion 32 of the second band 31 relative to the grooves 13, 14 when the second auxiliary handle 30 is attached to the handle attachment portion 10. Therefore, the first auxiliary handle 20 and the second auxiliary handle 30 can be attached to the handle attachment portion 10 at the same axial position. Therefore, the same feeling of use can be achieved when the first auxiliary handle 20 is attached and when the second auxiliary handle 30 is attached. This increases the freedom of selection of the auxiliary handle to be attached to the handle attachment portion 10, improving the usability of the power tool 1.

[0049] As shown in Figs. 9 and 13, the first projection 23 is provided on the axial end edges (front wall 22f and rear wall 22g) of the band holding portion 22. The second projection 32 is provided on the axial end edges (front end 31b and rear end 31c) of the second band 31. Therefore, the first projection 23 can be provided at a position where it abuts on the front ends 13a and 14a which are the axial end edges of the grooves 13 and 14 (see Figs. 5 and 6). The second projection 32 can be provided at a position where it abuts on the front ends 13a and 14a which are the axial end edges of the grooves 13 and 14. Therefore, the same grooves 13 and 14 can function as a retainer for both the first projection 23 and the second projection 32.

[0050] 5, 6 and 8, the handle attachment part 10 is provided with a plurality of grooves 13, 14 in the circumferential direction. Therefore, the first band 21 or the second band 31 is prevented from rotating or coming off at a plurality of points in the circumferential direction of the handle attachment part 10. This makes it possible to improve the position retention and attitude retention of the first band 21 or the second band 31 attached to the handle attachment part 10.

[0051] 5, 6 and 8, two of the multiple grooves 13, 14 are provided at positions facing each other in the radial direction of the handle attachment part 10. Therefore, the first band 21 or the second band 31 can be positioned at the two positions that are furthest apart in the radial direction of the handle attachment part 10. This makes it possible to further improve the ability to maintain the posture of the first band 21 or the second band 31 attached to the handle attachment part 10.

[0052] 5, 6 and 8, four or more grooves 13, 14 are provided at equal intervals in the circumferential direction of the handle attachment part 10. Therefore, the first auxiliary handle 20 or the second auxiliary handle 30 can be attached to the handle attachment part 10 in a plurality of positions rotated at a predetermined angle interval (for example, 90° interval) in the circumferential direction.

[0053] 1 and 2, the power tool 1 is a hammer drill equipped with a first auxiliary handle 20 or a second auxiliary handle 30. Therefore, by gripping the first auxiliary handle 20 or the second auxiliary handle 30 attached to the handle attachment part 10, the user can hold the tool body 2 in a stable position for the repeated striking motions of the hammer drill 1. Moreover, by switching between the first auxiliary handle 20 and the second auxiliary handle 30 depending on the state of use of the hammer drill 1, operability can be improved.

[0054] Various modifications can be made to the power tool 1 of the present embodiment described above. A hammer drill has been exemplified as the power tool 1. Instead of this, the power tool 1 may be applied to a power tool to which two types of auxiliary handles can be attached, such as a driver drill or a grinder, which is held by a user. The power tool 1 may be provided as a single product with the first auxiliary handle 20 or the second auxiliary handle 30, or both auxiliary handles. Alternatively, the power tool 1, the first auxiliary handle 20, and the second auxiliary handle 30 may each be provided as separate products.

[0055] The electric motor 6 is exemplified as the driving source, and the power tool 1 is exemplified in which power is supplied from an AC power source to the electric motor 6. Alternatively, for example, a rechargeable battery that is detachable from the tool body 2 may be used as the power supply source. For example, the present disclosure may be applied to power tools driven by other power sources such as air tools and engine tools.

[0056] An iron band has been exemplified as the first band 21. Alternatively, the first band 21 may be made of other metals having elasticity and rigidity, such as aluminum. An iron resin band has been exemplified as the second band 31. Alternatively, the second band 31 may be made of a material with high rigidity, such as metal.

[0057] A configuration in which the band holding portion 22 is provided with the first protrusion 23 that engages with the grooves 13, 14 has been exemplified. Instead of this, the first protrusion 23 may be provided on the first band 21. For example, the first protrusion 23 may be provided on both the first band 21 and the band holding portion 22. The handle attachment portion 10 having six grooves 13 and two grooves 14 has been exemplified. The number of grooves 13, 14 is not limited to that exemplified, and may be increased or decreased as appropriate. The angular interval between each groove 13, 14 is not limited to the exemplified 45° interval, and may be changed as appropriate depending on, for example, the number of grooves 13, 14. The groove 13 may be provided instead of the groove 14, and all grooves provided on the handle attachment portion 10 may be grooves 13.

[0058] The first auxiliary handle 20 has been exemplified in which the first band 21 is extended or retracted from the band holding portion 22 by rotating the grip 24 about an axis relative to the band holding portion 22. The structure for extending or retracting the first band 21 is not limited to this, and the first band 21 may be extended or retracted from the band holding portion 22 by, for example, a pulling operation. The second auxiliary handle 30 has been exemplified, and includes a second band 31 that expands or contracts by adjusting the circumferential width of the notch 31f by rotating the operating portion 33a of the fastening member 33. The structure for adjusting the circumferential width of the notch 31f is not limited to this, and the circumferential width of the notch 31f may be adjusted by, for example, a pulling operation or a pushing operation of the operating portion. [Explanation of symbols]

[0059] 1...Power tool (hammer drill) 2... tool body, 2a... tip portion, 2b... motor housing, 2c... gear housing 2d…Forward / reverse rotation switch lever 3…Chuck cover 4...Chuck, 4a...Tool insertion hole 5...Main handle, 5a...Trigger, 5b...Lock button, 5c...Power cord 6. Electric motor 7…Output shaft 10…Handle attachment part 11…Prevention part 12... Fastening surface 13...groove, 13a...front end, 13b...rear end 14...groove, 14a...front end, 14b...rear end 15…Cup attachment part 20…First auxiliary handle (auxiliary handle) 21...first band, 21a...inner circumferential surface, 21b...front end, 21c...rear end 21d: longitudinal end portion; 21e: insertion hole 22... band holding portion, 22a... opening, 22b... box-shaped recess, 22c... flange portion, 22d... through hole 22e...Pole insertion hole, 22f...Front wall (inner circumference, edge), 22g...Rear wall (inner circumference, edge) 23...first protrusion, 23a...(front) first protrusion, 23b...(rear) first protrusion 24...grip, 24a...flange, 24b...through hole, 24c...nut engagement recess 25...fastening mechanism, 25a...hexagonal nut 26... band connecting member, 26a... insertion portion, 26b... screw shaft portion 27...unlock button, 27a...pole engagement portion, 27b...compression spring 30…Second auxiliary handle (auxiliary handle) 31... second band, 31a... inner peripheral surface, 31b... front end (edge), 31c... rear end (edge) 31d, 31e...circumferential end, 31f...notch 32...second protrusion, 32a...front end, 32b...rear end 33... fastening member, 33a... operating portion, 33b... bolt, 33c... hexagonal nut 34…grip, 34a…tsuba (hand guard) C…Axis center

Claims

1. A power tool, a main handle that is integrally provided on the tool body; a cylindrical handle attachment portion provided on the tool body to which a first auxiliary handle or a second auxiliary handle can be detachably attached; A groove is formed on the outer peripheral surface of the handle attachment portion and extends in the axial direction, The first auxiliary handle has an arc-shaped first band, a band holding portion that holds both ends of the first band in a retractable manner and changes the diameter of the first band, and a first protrusion that protrudes radially inward from an inner peripheral surface of the first band and / or the band holding portion and engages with the groove, The second auxiliary handle is a power tool having a second band having an arc shape with an axial notch, a fastening member that adjusts the circumferential width of the notch in the second band to change the diameter of the second band, and a second protrusion that protrudes radially inward from the inner surface of the second band and engages with the groove.

2. 2. The power tool of claim 1, The tool body has a shape in which the diameter of the portion forward of the handle attachment portion is the same as or smaller than the diameter of the handle attachment portion.

3. 3. The power tool according to claim 1 or 2, The handle attachment portion has a fastening surface that abuts against the inner peripheral surface of the first band or the inner peripheral surface of the second band, and a retaining portion that is located at an end of the groove in the axial direction and protrudes from the groove, and the retaining portion restricts movement of the first protrusion and the second protrusion in the axial direction, A power tool in which the retaining portion has the same radial height as the fastening surface or a radial height lower than the fastening surface.

4. 4. The power tool of claim 3, A power tool, wherein the groove is longer in the axial direction than the axial width of the first projection and longer in the axial direction than the axial width of the second projection.

5. 3. The power tool according to claim 1 or 2, A power tool in which the axial position of the first protrusion of the first band relative to the groove when the first auxiliary handle is attached to the handle attachment portion is the same as the axial position of the second protrusion of the second band relative to the groove when the second auxiliary handle is attached to the handle attachment portion.

6. 3. The power tool according to claim 1 or 2, the first protrusion is provided on an edge of the first band and / or the band holding portion in the axial direction, The second protrusion is provided on an axial end edge of the second band.

7. 3. The power tool according to claim 1 or 2, The handle attachment portion is provided with a plurality of grooves in a circumferential direction.

8. 8. The power tool of claim 7, Two of the plurality of grooves are provided at positions opposite to each other in the radial direction of the handle attachment portion.

9. 8. The power tool of claim 7, The plurality of grooves may be four or more and may be equally spaced apart in the circumferential direction of the handle attachment portion.

10. A hammer drill comprising the first auxiliary handle or the second auxiliary handle according to claim 1 or 2.

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