Impact tool

Abstract

The present application provides a kind of impact tool.Hammer drill (1) includes tool holder (10), two balls (35,35) being arranged in the receiving hole (45,45) of tool holder, the guide washer (33) of the front side of ball to the receiving hole by helical spring (34) force, press ring (32) is arranged adjacent to the front side of guide washer and the operation sleeve (31) of the front and back movement of press ring between the locking position and the locking release position of two balls.In the front surface of guide washer, protruding portion (42) is provided to the side of press ring, by protruding portion (42), in the locking position of press ring guide washer becomes the inclined attitude from the axis (A) of tool holder, so that one ball (35) can be more rearward than the other ball (35) moves.Accordingly, by making two balls reliably retreat, tip tool can be smoothly inserted into tool holder.

Description

TECHNICAL FIELD

[0001] The present application relates to an electric hammer, hammer drill, or the like impact tool. BACKGROUND

[0002] An electric hammer, hammer drill, or the like impact tool converts rotation of a motor inside a housing into forward and backward movement of a piston through a crank mechanism or the like. And, an impact member that moves forward and backward in linkage with the piston directly or indirectly impacts a rear end of a tip tool installed to a tool holder.

[0003] In this impact tool, a chuck mechanism (mounting portion) for inserting the tip tool to the tool holder is provided at a tip end of the housing. In this mounting portion, as disclosed in Patent Literature 1, a pair of balls that can move in an axial direction and a radial direction of the tool holder are housed in a pair of housing holes provided to be penetrated through the tool holder. The balls are forced to a position in front of the housing hole by a guide washer (abutting member) that is forced to the front by a coil spring. A press ring is externally attached to the tool holder. The press ring can move forward and backward between a locked position where the press ring is positioned outside the balls and protrudes the balls into the tool holder, and an unlocked position where the press ring retreats from the outside of the balls to the rear and allows the balls to retreat from the tool holder. The press ring is held to the inner periphery of an operation sleeve and is forced to the locked position by a coil spring. When the operation sleeve is made to retreat, the press ring slides to the unlocked position, so that the tip tool can be detached and attached.

[0004] The guide washer has a receiving portion of a conical shape that protrudes to the rear as it approaches the center. A retreat portion is concavely provided at a part of the receiving portion, the retreat portion protrudes to the rear with an angle with respect to the axis of the tool holder that is smaller than that of the other portion. The positions of the two balls are shifted forward and backward by making the lower ball fit in the retreat portion.

[0005] In the attachment portion, when the rear end of the tip tool is inserted into the tool holder, the upper ball first pushes into between the pressing ring and the receiving portion and retreats from inside the tool holder, thereby tilting the guide washer. When the tip tool is further retracted, the lower ball also pushes into between the pressing ring and the receiving portion and retreats from inside the tool holder. And, when the groove provided to the outer periphery of the tip tool reaches the position of the balls, the two balls advance by the urging force of the coil spring and are engaged in the groove, thereby integrating the tip tool with the tool holder in the rotational direction. Therefore, even without retracting the operation sleeve, the tip tool can be inserted and attached (inserted and attached) to the tool holder by just pushing.

[0006] [Related Art Documents]

[0007] [Patent Documents]

[0008] Patent Document 1: Japanese Patent No. 4949886 SUMMARY

[0009] [Problems to be Solved by the Invention]

[0010] However, the invention of Patent Document 1 causes the position of the ball to shift due to the retreat portion provided locally to the guide washer, and thus, when the tip tool is inserted, the ball cannot smoothly retreat to the retreat portion. It is also considered to increase the protruding amount of the retreat portion to the rear to increase the moving range of the ball, but when the tip tool is inserted, the component force in the radial direction of the guide washer is larger than the component force in the pushing direction of the guide washer by the retreat portion, and thus, there is a concern that the tip tool cannot be pushed.

[0011] Therefore, an object of the present invention is to provide an impact tool that can smoothly insert and attach a tip tool to a tool holder by reliably retreating two balls.

[0012] [Means for Solving the Problems]

[0013] To achieve the above object, the present application is an impact tool including a tool holder of a cylindrical shape, two balls, an abutting member of a ring shape, a pressing ring, and an operation sleeve, wherein a tip tool is capable of being inserted into the tool holder from the front; the two balls are disposed in a pair of housing holes provided in the tool holder in the radial direction so as to be movable forward and backward in the axial direction of the tool holder and so as to be able to be tilted in the axial direction inside the tool holder; the abutting member of the ring shape is externally attached to the tool holder so as to be movable forward and backward, and the two balls are forced by a force applying member toward the front side of the housing hole; the pressing ring is externally attached to the tool holder so as to be movable forward and backward and is disposed adjacent to the front side of the abutting member, and is forced by the force applying member toward the front; the operation sleeve is externally attached to the tool holder and abuts the pressing ring on the inner peripheral side, and is movable forward and backward between a locking position on the front side and a locking release position on the rear side, wherein the locking position on the front side is a position in which the pressing ring is positioned outside the two balls on the front side of the housing hole and the two balls are projected toward the axial direction inside the tool holder, and the locking release position on the rear side is a position in which the pressing ring is retreated from the outside of the two balls and the two balls are allowed to retreat from the projected position projected toward the inside of the tool holder, and the impact tool is characterized in that a projection projecting toward the other side is provided on at least one of the facing surfaces of the abutting member and the pressing ring, and by the projection, the abutting member becomes a tilted attitude inclined from the axis of the tool holder in the locking position of the pressing ring, so that the ball of either side is capable of being moved more toward the rear than the ball of the other side.

[0014] [Effect of the Invention]

[0015] According to the present application, the tip tool is smoothly inserted into the tool holder by reliably retreating the two balls. Therefore, the insertion performance of the tip tool is improved.

[0016] [Explanation of Reference Numerals]

[0017] 1: hammer drill; 2: main body case; 3: motor case; 4: motor; 5: output shaft; 10: tool holder; 17: large diameter portion; 18: small diameter portion; 20: piston; 24: impact piece; 25: intermediate piece; 26: stopper rubber; 30: mounting portion; 31: operation sleeve; 32: pressing ring; 33, 33a: guide washer; 34: coil spring; 35: ball; 40: receiving portion; 40A: lower half portion side; 40B: upper half portion side; 41: inner side flat portion; 42: projection portion; 43: outer side flat portion; 45: housing hole; 50: tip tool; 51: tapered end portion; A: axis of tool holder. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a central longitudinal sectional view of the hammer drill.

[0019] Figure 2A indicates a state before installation of the tip tool, Figure 2B indicates an initial pressing state of the tip tool, Figure 2C indicates a state of further pressing the tip tool.

[0020] Figure 3A indicates a state of further pressing the tip tool to roll the two balls to the tapered end portion, Figure 2C indicates a state of further pressing the tip tool to roll the two balls to the outer periphery of the tip tool, Figure 3B indicates a state of further pressing the tip tool to engage the two balls with the groove. Figure 3C

[0021] Figures 4A-4C is an explanatory view of the guide washer, wherein, Figure 4A indicates a perspective view of the guide washer viewed from the front, Figure 4B indicates a front view, Figure 4C indicates a central longitudinal sectional view.

[0022] Figures 5A-5C is an explanatory view of the guide washer of a modification, wherein, Figure 5A indicates a perspective view of the guide washer viewed from the front, Figure 5B indicates a front view, Figure 5C indicates a central longitudinal sectional view. DETAILED DESCRIPTION

[0023] In one embodiment of the present application, the protruding portion can be provided to the front surface of the abutting member. According to this structure, the inclined posture of the abutting member can be simply obtained.

[0024] In one embodiment of the present application, the abutting member can be a disc shape which is equal in the circumferential direction except for the protruding portion. According to this structure, the shape of the abutting member becomes simple.

[0025] In one embodiment of the present application, the central portion of the abutting member can be a conical shape which gradually retreats toward the center. According to this structure, the balls can be smoothly moved to the rear.

[0026] In one embodiment of the present application, the portion of the conical shape can be bulged to the rear in a manner that the angle with respect to the axis of the tool holder becomes smaller in a part in the circumferential direction, and the protruding portion is provided to the radially outer side of the part, and one ball can be further moved to the rear through the bulged portion of the conical shape. According to this structure, the ball can be more reliably retreated to the rear.

[0027] ​In one embodiment of the present application, the conical shape can be provided to the central portion of the abutting member, and a flat surface portion can be provided to the outer periphery of the central portion. According to this structure, the pressing ring can be stably forced even if the protruding portion is provided to the abutting member.

[0028] In one embodiment of the present application, the force applying member can be a conical spiral spring whose diameter gradually increases as it approaches the front. According to this structure, the applied force can be efficiently transmitted in accordance with the shape of the abutting member.

[0029] In one embodiment of the present application, a second flat surface portion for abutting the front end of the spiral spring can be formed to the outer periphery of the abutting member. According to this structure, the force applying state of the abutting member is stable.

[0030] [Embodiment]

[0031] Hereinafter, an embodiment of the present application will be described with reference to the drawings.

[0032] Figure 1 is a central longitudinal sectional view showing an example of a hammer drill 1 as an impact tool.

[0033] The hammer drill 1 is connected to a motor housing 3 in the lower portion of the front side of a main housing 2 in the up-and-down direction. A motor 4, which makes an output shaft 5 face upward, is housed in the motor housing 3. In the main housing 2, a gear housing 6 is provided above the motor housing 3. A crank shaft 7 and an intermediate shaft 8, which engage with the output shaft 5, are provided in parallel in the gear housing 6. A front housing 9, which is a cylinder extending forward, is assembled to the front side of the gear housing 6. In the front housing 9, a tool holder 10, which is a cylinder, is supported coaxially and rotatably. A handle housing 11 is connected to the rear portion of the main housing 2. A housing cover 12 for covering the front housing 9 is connected to the front portion of the main housing 2.

[0034] The intermediate shaft 8 engages with a bevel gear 13 provided to the rear end of the tool holder 10. A switch 14 and a switch operating lever 15 are provided to the handle housing 11. A power supply cord 16 is connected to the lower portion of the handle housing 11.

[0035] The tool holder 10 is a large diameter portion 17 in the front housing 9. The front end of the large diameter portion 17 is a small diameter portion 18, which becomes slender as it approaches the front and protrudes from the front housing 9. An attachment portion 30 for inserting an attachment top tool 50 is provided to the small diameter portion 18. The attachment portion 30 will be described later.

[0036] A piston 20 is provided in the large diameter portion 17. The piston 20 is connected to the eccentric pin 21 of the crank shaft 7 through a connecting rod 22. In front of the piston 20, an impact member 24 is housed in the large diameter portion 17 through an air chamber 23. In front of the impact member 24, an intermediate member 25 is housed in the large diameter portion 17.

[0037] A not-shown switching operation handle is provided on the left side surface of the main body case 2. By operating the switching operation handle, three operation modes of a hammer mode, a hammer drill mode, and a drill mode can be selected. In the hammer mode, the crank shaft 7 is rotated in a state where the rotation of the tool holder 10 is locked to apply an impact to the tip tool 50. In the hammer drill mode, the crank shaft 7 and the intermediate shaft 8 are simultaneously operated to apply an impact and rotation to the tip tool 50. In the drill mode, the intermediate shaft 8 is rotated without applying an impact to rotate the tip tool 50 together with the tool holder 10.

[0038] Also as Figure 2A shown, an annular stopper rubber 26 is attached to the tip of the small diameter portion 18 of the tool holder 10. An attachment portion 30 is provided between the stopper rubber 26 and the front case 9. The attachment portion 30 has an operation sleeve 31, a pressing ring 32, a guide washer 33, a coil spring 34, and two ball bearings 35, 35.

[0039] The operation sleeve 31 is externally attached to the small diameter portion 18 between the stopper rubber 26 and the front case 9, and is movable forward and backward. An annular stopper portion 36 is formed on the inner periphery of the operation sleeve 31. The stopper portion 36 abuts against the stopper rubber 26 at the advanced position of the operation sleeve 31.

[0040] The pressing ring 32 is externally attached to the small diameter portion 18 in the operation sleeve 31. The inner periphery of the pressing ring 32 is formed in a stepped shape of a large diameter portion 37 at the front side, a small diameter portion 38 at the rear side, and a tapered portion 39 connecting the both. The pressing ring 32 is movable forward and backward in the operation sleeve 31, and is restricted from advancing forward at the position where it abuts against the stopper portion 36.

[0041] The guide washer 33 is a disc shape externally attached to the small diameter portion 18 in the operation sleeve 31. The diameter of the guide washer 33 is larger than that of the pressing ring 32, and the central portion is a bearing portion 40 of a conical shape protruding rearward as it approaches the center from the outer periphery. However, the conical shape of the bearing portion 40 is not uniform over the entire circumference, but as shown in Figures 4A-4C the drawing, is formed to be non-uniform in the up-down direction in such a manner that the angle of the upper half portion side 40B of the bearing portion 40 with respect to the axis A of the tool holder 10 is smaller than that of the lower half portion side 40A of the bearing portion 40. Accordingly, the protruding amount of the upper half portion side 40B protruding rearward is larger than that of the lower half portion side 40A.

[0042] An inner side flat portion 41 orthogonal to the axis A is formed on the outer periphery of the receiving portion 40. A protruding portion 42 protruding forward is formed on the upper side of the inner side flat portion 41 in the center in the left-right direction. An outer side flat portion 43 orthogonal to the axis A is formed on the outermost periphery of the guide washer 33.

[0043] The coil spring 34 is externally fitted between the front end of the large diameter portion 17 of the tool holder 10 and the guide washer 33 in the small diameter portion 18. The coil spring 34 is conical in shape becoming smaller in diameter toward the rear from the front end. The front end of the coil spring 34 abuts against the rear surface of the outer side flat portion 43 of the guide washer 33. The rear end of the coil spring 34 abuts against the front end of the large diameter portion 17.

[0044] Therefore, the coil spring 34 exerts a force on the guide washer 33 in the forward direction, and exerts a force on the press ring 32 and the operation sleeve 31 in the forward direction via the guide washer 33.

[0045] In Figure 2A In the normal state shown, the operation sleeve 31 is located in an advanced position abutting against the stopper rubber 26 by the force of the coil spring 34. The press ring 32 is located in an advanced position abutting against the stopper portion 36 of the operation sleeve 31. The guide washer 33 is located in an advanced position with the inner side flat portion 41 abutting against the rear surface of the press ring 32.

[0046] However, since the protruding portion 42 of the guide washer 33 abuts against the rear surface on the upper side of the press ring 32, the guide washer 33 abuts against the press ring 32 in an inclined attitude with the upper side located further rearward than the lower side in the advanced position, not coaxial with the axis A.

[0047] A pair of housing holes 45, 45 are formed in the small diameter portion 18 of the tool holder 10. The housing holes 45, 45 are disposed in point-symmetrical positions with the axis A as the center, and pass through the small diameter portion 18 in the radial direction. The housing hole 45 is formed longer in the front-rear direction, and the both ends in the front-rear direction are formed in a tapered shape becoming slender toward the axis A side from the outer surface of the small diameter portion 18. A pair of protrusions 46, 46 extending in the front-rear direction are formed on the inner periphery of the small diameter portion 18 at positions differing by 90° in phase from the housing hole 45.

[0048] The balls 35, 35 are housed in the housing holes 45, 45, and can roll in the front-rear direction in the housing hole 45, respectively. Each ball 35 can also roll in the radial direction in the housing hole 45. Each ball 35 can roll to a position protruding partially into the small diameter portion 18 on the axis side of the small diameter portion 18. In Figure 2A In the advanced position (locked position) of the operation sleeve 31 and the press ring 32 shown, the reduced diameter portion 38 of the press ring 32 is located on the outer side of the balls 35, 35. Therefore, the balls 35, 35 are locked in the protruding position protruding into the small diameter portion 18, and are restricted from moving to the radial outer side.

[0049] In this state, the lower half 40A of the receiving portion 40 of the guide washer 33 abuts against the lower ball 35A (hereinafter, when distinguishing between upper and lower, the lower ball is marked as 35A and the upper ball is marked as 35B). Therefore, the ball 35A is locked in the protruding position protruding into the small diameter portion 18 on the front side of the receiving hole 45.

[0050] On the other hand, the upper half 40B of the receiving portion 40, which has a larger tilt angle, is more rearward than the lower half 40A. Therefore, a retraction space S is formed between the pressing ring 32 and the upper half 40B, allowing the ball 35B to move rearward. However, even when the ball 35B retracts to abut against the upper half 40B, its contact with the reduced-diameter portion 38 of the pressing ring 32 remains unchanged. Therefore, the protruding position of the ball 35B protruding into the smaller-diameter portion 18 is maintained.

[0051] A tapered end 51 that tapers towards the rear is formed at the rear end of the tip tool 50. A pair of grooves 52, 52 are formed at a point symmetrical about the axis on the outer periphery of the rear end of the tip tool 50 in the front-rear direction. At a position 90° out of phase with the grooves 52, 52, a pair of engaging grooves 53, 53 extending forward from the rear end are formed on the outer periphery of the rear end of the tip tool 50.

[0052] In the hammer drill 1 configured as described above, when the tip tool 50 is inserted (installed and mounted) into the mounting portion 30, as... Figure 2A As shown, with the operating sleeve 31 in the forward position, the rear end of the tip tool 50 is inserted into the small diameter portion 18 such that the engaging grooves 53, 53 mate with the protrusions 46, 46 of the small diameter portion 18. Then, the tapered end 51 of the tip tool 50 abuts against the balls 35A, 35B. However, since a retraction space S is formed behind the upper ball 35B, the ball 35B retracts within the receiving hole 45 while abutting against the pressing ring 32. At this time, as... Figure 2B As shown, the ball bearing 35B retracts until its center is located behind the rear end of the pressing ring 32 and abuts against the upper half of the receiving part 40 side 40B. Therefore, it does not hinder the retraction of the tip tool 50.

[0053] As the top tool 50 continues to move backward, such as Figure 2CAs shown, the lower ball 35A is pushed by the tapered end 51 of the tip tool 50 to move to the rear of the housing hole 45. Then, the ball 35A is squeezed between the pressing ring 32 and the lower half side 40A of the receiving portion 40. Thus, the ball 35A moves the lower portion of the guide washer 33 rearward. Next, the upper ball 35B is also pushed by the tapered end 51 to move to the rear of the housing hole 45. Then, the ball 35B is squeezed between the pressing ring 32 and the upper half side 40B of the receiving portion 40. Thus, the ball 35B moves the upper portion of the guide washer 33 rearward.

[0054] When the tip tool 50 is further retracted, as shown in FIG. 6, the balls 35A, 35B move to the radially outer side between the pressing ring 32 and the guide washer 33 while rolling relatively to the tapered end 51. Since the balls 35A, 35B always abut against the pressing ring 32, the pressing ring 32 is not retracted even if the hammer drill 1 is directed upward. Figure 3A

[0055] Then, when the tip tool 50 is further retracted, as shown in FIG. 7, the balls 35A, 35B roll relatively over the tapered end 51 onto the rear end peripheral surface of the tip tool 50 and retreat radially outward from the housing holes 45, 45. When the tip tool 50 is retracted in this state, the grooves 52, 52 reach the inner side of the balls 35A, 35B. Then, as shown in FIG. 8, the balls 35A, 35B are pushed by the receiving portion 40 of the guide washer 33 to move to the inner side of the pressing ring 32, thereby returning from the housing holes 45, 45 to the projected positions. Thus, the balls 35A, 35B are engaged with the grooves 52, 52. In this way, the tip tool 50 is prevented from being detached by the balls 35A, 35B and is integrated with the tool holder 10 in the rotational direction. Figure 3B Figure 3C

[0056] After the tip tool 50 is installed, the operation mode is selected by switching the operation handle and the push operation is performed on the switch operation handle 15. Then, the switch 14 is turned on to drive the motor 4, so that the output shaft 5 is rotated.

[0057] In the hammer mode, the rotation of the output shaft 5 is transmitted to the crank shaft 7. However, the rotation of the intermediate shaft 8 is not transmitted from the bevel gear 13 to the tool holder 10. Thus, the piston 20 is moved forward and rearward via the connecting rod 22 by the eccentric movement of the eccentric pin 21. Then, the impact piece 24 is moved forward and rearward by the air chamber 23, and the impact piece 24 indirectly impacts the tip tool 50 through the intermediate piece 25. Thus, the tip tool 50 can perform cutting or the like on the work material.

[0058] ​​​In the case of the hammer drill mode, the rotation of the output shaft 5 is transmitted to the crank shaft 7. In addition, the rotation of the intermediate shaft 8 is transmitted to the tool holder 10 from the bevel gear 13. Therefore, the tool holder 10 rotates, and the tip tool 50 rotates along with the impact.

[0059] On the other hand, in the case of the drill mode, the crank shaft 7 does not rotate, and the rotation of the intermediate shaft 8 is transmitted to the tool holder 10. Therefore, the piston 20 does not move back and forth, and the tip tool 50 rotates to be able to perforate the work material or the like.

[0060] Further, in the case where the tip tool 50 is detached from the tool holder 10, the operation sleeve 31 is retracted from the state shown in Fig. 1 against the urging force of the coil spring 34. Then, the press ring 32 is also retracted by being pushed by the stopper 36, and thus the guide washer 33 is also retracted. Therefore, the press ring 32 moves to the lock release position where the diameter-enlarged portion 37 becomes outside of the balls 35, 35. When the tip tool 50 is pulled toward the front in this state, the balls 35, 35 engaged with the grooves 52, 52 are disengaged from the grooves 52, 52 and move to the radial outside of the housing holes 45, 45. Therefore, the tip tool 50, from which the prevention of detachment based on the balls 35, 35 is released, can be pulled out. Figure 3C

[0061] Thus, according to the hammer drill 1 of the above-described mode, the protruding portion 42 (protruding portion) protruding toward the press ring 32 is provided on the facing surface of the guide washer 33 (abutting member) facing the press ring 32. By this protruding portion 42, the guide washer 33 is brought into the inclined attitude inclined from the axis A of the tool holder 10 at the lock position of the press ring 32, and thus the ball 35B can move more rearward than the ball 35A.

[0062] According to this structure, the tip tool 50 can be smoothly inserted into the tool holder 10 by reliably retreating the two balls 35A, 35B. Therefore, the insertion performance of the tip tool 50 is improved.

[0063] The protruding portion 42 is provided to the front surface of the guide washer 33. Therefore, the inclined attitude of the guide washer 33 can be simply obtained.

[0064] The guide washer 33 is a circular disc shape equal in the circumferential direction except for the protruding portion 42. Therefore, the shape of the guide washer 33 becomes simple.

[0065] The central portion of the guide washer 33 is a receiving portion 40 of a conical shape gradually retracted toward the center. Therefore, the balls 35A, 35B can smoothly move rearward.

[0066] ​The upper half portion side 40B (a portion in the circumferential direction) of the receiving portion 40 is bulged toward the rear in a manner that the angle with respect to the axis A of the tool holder 10 is reduced. Further, a protruding portion 42 is provided on the radially outer side of the upper half portion side 40B, and the ball 35B is able to move further toward the rear through the upper half portion side 40B. Therefore, the ball 35B is able to be more reliably evacuated toward the rear.

[0067] The receiving portion 40 of the conical shape is provided to the central portion of the guide washer 33, and an inner side flat portion 41 (flat portion) is provided to the outer periphery of the central portion. Therefore, even if the protruding portion 42 is provided to the guide washer 33, the pressing ring 32 is able to be stably applied with the force.

[0068] The force applying member that applies the force to the guide washer 33 is the conical spring 34 whose diameter is gradually increased toward the front. Therefore, the applied force is able to be efficiently transmitted in conformity with the shape of the guide washer 33.

[0069] The outer side flat portion 43 (second flat portion) for the front end of the conical spring 34 to abut is formed on the outer periphery of the guide washer 33. Therefore, the force application state of the guide washer 33 is stable.

[0070] Next, a modification of the present application will be described.

[0071] The bulged portion of the receiving portion can also be a portion that is smaller than half in the circumferential direction if the ball is able to be evacuated. However, the bulged portion without the abutting member can also be acceptable. For example, the receiving portion 40 can also be made into the conical shape that is uniform in the circumferential direction as the guide washer 33a as shown. Figures 5A-5C In this case, the inclined posture of the guide washer 33a is also able to be obtained by the protruding portion 42.

[0072] The abutting member can be the conical shape as a whole instead of the central portion. Conversely, the abutting member can also be a shape other than the conical shape (for example, a spherical shape or a flat shape).

[0073] The structure in which the abutting member is integrated with the tool holder in the rotational direction (for example, the fitting of the widths of the sides to each other) can be adopted between the abutting member and the tool holder.

[0074] The shape of the protruding portion is not limited to the protruding portion of the above-described manner. The protruding portion can also be a protrusion that is formed long in the circumferential direction. A plurality of protruding portions can also be provided.

[0075] The protruding portion can also be provided to the rear surface of the pressing ring instead of being provided to the abutting member. The manner of the protruding portion in this case can also be appropriately changed. The protruding portion can also not be provided, and the abutting member can be inclined by locally increasing the wall thickness of the pressing ring.

[0076] The protrusions can also be provided on the facing surfaces of both the abutting member and the pressing ring.

[0077] The coil spring is not limited to the conical shape. A force applying member other than the coil spring can also be used.

[0078] In the above-described manner, an example in which a pair of the housing holes and the balls are arranged above and below the tool holder is described, but the present application is not limited to this arrangement. The present application also includes a case in which the housing holes and the balls are arranged to the left and right of the tool holder or are arranged to other phases.

[0079] The hammer drill can also have, for example, a structure in which the impact section has an intermediate shaft parallel to the tool holder, and an arm that can swing by a swash bearing that tilts the axis is provided on a boss sleeve provided on the intermediate shaft, so that a piston cylinder connected to the arm can move forward and backward.

[0080] The orientation and type of the motor are not limited to the above-described manner.

[0081] The operation mode is not limited to the three modes (hammer mode, hammer drill mode, drill mode) described above. For example, it can be possible to select only two operation modes, the hammer drill mode and the hammer mode.

[0082] The motor can not be an AC motor, but can be a DC motor in which a battery pack is installed as a power source.

[0083] The impact tool is not limited to the hammer drill, and the present application can also be applied to the attachment section even if it is an electric hammer that has only an impact section.

Claims

1. An impact tool comprising a cylindrical tool holder, two balls, an annular abutment member, a pressing ring, and an operating sleeve, wherein, The cylindrical tool holder allows the rear end of the top tool to be inserted from the front; The two balls are radially disposed within a pair of receiving holes in the tool holder, such that they can move back and forth in the axial direction of the tool holder and can enter and exit the axial side within the tool holder; The abutting member is externally mounted to the tool holder in a manner that allows it to move back and forth, and the force-applying member applies force to the two balls toward the front side of the receiving hole; The pressing ring is externally mounted to the tool holder in a back-and-forth movable manner and is disposed adjacent to the front side of the abutting member, and is subjected to forward force by the force-applying member; The operating sleeve is externally mounted to the tool holder and abuts against the pressing ring on its inner circumferential side. It is movable back and forth between a front locked position and a rear unlocked position. The front locked position is where the pressing ring is located outside the two balls on the front side of the receiving hole, causing the two balls to protrude towards the axis within the tool holder. The rear unlocked position is where the pressing ring retracts from the outside of the two balls, allowing the two balls to retract from their protruding position within the tool holder. The impact tool is characterized in that... At least one of the opposing surfaces of the abutting member and the pressing ring is provided with a protrusion that protrudes toward the other side. Through the protrusion, in the locked position of the pressing ring, the abutting member is in an inclined posture that is tilted from the axis of the tool holder, so that the ball of one side can move further back than the ball of the other side.

2. The impact tool according to claim 1, characterized in that, The protrusion is provided on the front surface of the abutment member.

3. The impact tool according to claim 2, characterized in that, The abutting member is a disc shape that is uniformly circular in the circumferential direction, except for the protrusion.

4. The impact tool according to claim 3, characterized in that, At least the central portion of the abutting member is a conical shape that gradually recedes towards the center.

5. The impact tool according to claim 4, characterized in that, The conical portion bulges rearward in a manner that decreases in angle relative to the axis of the tool holder in the circumferential direction, and the protrusion is provided on the radially outer side of the portion, through which one of the ball bearings can move further rearward.

6. The impact tool according to claim 4, characterized in that, The conical shape is provided in the central portion of the abutting member, and a flat portion is provided on the outer periphery of the central portion.

7. The impact tool according to any one of claims 1 to 6, characterized in that, The force-applying component is a conical helical spring whose diameter gradually increases as it moves forward.

8. The impact tool according to claim 7, characterized in that, A second planar portion is formed on the outer periphery of the abutting member, where the front end of the helical spring abuts.

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