JP2006007389A - Impact tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a socket attaching and detaching mechanism of an impact tool, preventing lowering of transmission efficiency of impact energy due to rattle between an anvil and a socket and fatigue rupture of the anvil, and further simply performing attachment and detachment of a socket. <P>SOLUTION: This impact tool includes: a groove 17c formed along the direction of the rotation axis of an output shaft 17 of the anvil 18; an energizing elastic body part 50b extending along the inside of the groove; and a fixing part 50f for fixing one end side of the energizing elastic body part 50b to the square output shaft 17, wherein when a socket body 1 is fitted and mounted to the square output shaft 17c, the pressing force based on the elastic deformation in the groove 17c of the energizing elastic body part 50b energizes the socket body 1 in the opposite direction to the rotating direction of the square output shaft 17. On the other hand, a locking elastic body part 50a is disposed parallel to the energizing elastic body part 50b, and a projection part 50d of the locking elastic body part 50a is engaged with a locking hole 1a of the socket, whereby the socket body can be simply attached and detached to and from the square output shaft 17. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an impact tool that functions as a driver or a wrench capable of firmly tightening a screw by striking or impacting in the screw tightening rotation direction, and more particularly to a socket attaching / detaching structure used for the impact tool.

  In general, an impact tool uses an electric motor as a drive source, and the drive source is composed of, for example, a plurality of planetary gears that mesh with gear teeth provided on a rotating shaft of the electric motor and a ring gear that meshes with the planetary gear. It is decelerated by the power transmission mechanism and gives a rotational force to the spindle. A hammer is provided on the outer periphery on the tip side of the spindle to give a rotational hit to the anvil. The anvil is mounted with a socket body, which is a bolt tightening tool, at its tip, and is disposed so as to be freely rotatable on the same axis as the spindle. The spindle and the hammer are connected via a cam mechanism including a cam groove provided in each of the spindle and the hammer and a ball fitted in the cam groove, and the rotation of the spindle is transmitted to the hammer. The hammer and the spindle are engaged with each other through claws provided on the opposing surfaces. When a load exceeding a certain value is applied to the hammer, the hammer rotates with the spindle and moves away from the anvil. The nail is dissociated by moving. When the load on the hammer is erased as the claws are dissociated, the hammer moves forward while rotating in the direction approaching the anvil by the pressing force of the spring, and the claws are impactably engaged with each other. Therefore, the hammer hits the anvil in a rotational manner, and thereby, the bolt is subjected to the rotational impact from the anvil through the socket to be screwed. The configuration of such an impact tool is disclosed, for example, in Patent Document 1 below. In this impact tool, the anvil, which is the output shaft of the impact tool, has a square cross section at its tip, such as a square or a hexagon, and it corresponds to the size of the bolt or nut to be tightened or released. One end of the selected socket body has a socket attachment / detachment structure for fitting or locking.

  As a first example of an impact tool having a typical conventional socket attaching / detaching structure, there is one shown in FIGS. As shown in FIG. 26 and FIG. 27, the anvil output shaft is fitted to the rear end of the socket body 1 that functions as a wrench (in the following description, “socket body” may be simply referred to as “socket”). A rectangular hole 1b is provided, and a fastening hexagonal hole 1d into which a nut or the like is fitted is provided at the tip. On the other hand, as shown in FIGS. 23 and 25, a locking hole (for inserting a square output shaft 5 b such as a square and a pin 6 at the tip of an anvil 5 mounted on a conventional impact tool body 4 ( Through hole) 5a. The output shaft 5b of the anvil is inserted so as to fit or lock into a square hole 1b such as a square of the socket 1. Further, as shown in FIGS. 23 and 24, the square output shaft 5b of the anvil and the square hole 1b of the socket are fitted and communicated with the anvil locking hole 5a and the socket locking hole 1a. By inserting the cylindrical pin 6, the socket 1 is prevented from being detached from the anvil 5. Further, a groove 1c is provided on the outer periphery of the socket 1 where the locking hole 1a is located, and the cylindrical pin 6 is detached from the locking holes 1a and 5a by covering the groove 1c with the elastic ring 2. It has a structure that prevents this.

  As a second example of an impact tool having a conventional socket attaching / detaching structure, there is a structure as shown in FIG. In the technique disclosed in Patent Document 1, in order to eliminate the shakiness of the socket and improve the efficiency of torque transmission, an elastic body that presses the output shaft in a direction perpendicular to the shaft, that is, in the radial direction is provided on the socket. Proposed.

JP-A-8-229835

  However, in the first example of the conventional impact tool, since various fastening members are used in actual fastening work, the socket body 1 needs to be frequently replaced each time, and the socket body at the time of fastening work is also required. Therefore, it is necessary to replace the socket body 1 frequently. However, when replacing the socket body 1, the elastic ring 2 is removed from the groove 1c using a tool such as a flat-blade screwdriver, and the locking hole 1a of the socket body 1 and the rectangular output shaft 5 of the impact tool body 4 are replaced. Since it is necessary to remove the insertion pin 6 communicated with the locking hole 5a, there is a problem that it takes time to attach and detach, so that work efficiency does not increase and a tool such as a flat-blade screwdriver must always be carried. . Further, since the fitting portion between the rectangular output shaft 5b of the anvil and the rectangular hole 1b of the socket body has a rattling, there is a problem that the transmission impact energy is reduced due to the influence of the rattling. Further, the rectangular output shaft 5b of the anvil has a through-hole portion 5a, and there is a problem that a fatigue failure occurs from the through-hole portion 5a due to long-term use, and the fastening operation itself is interrupted.

  Further, in the second example of the conventional impact tool described in Patent Document 1, since a means for preventing rattling is provided on the socket, there is a problem in that a commercially available socket cannot be used. .

  Accordingly, it is a primary object of the present invention to provide an impact tool including a socket attachment / detachment structure that prevents a reduction in impact energy transmission efficiency due to rattling that exists between an anvil and a socket that are fitted to each other.

  Another object of the present invention is to provide an impact tool having a socket attachment / detachment structure that prevents damage due to fatigue failure of an anvil and allows the socket to be attached / detached relatively easily without using other tools. is there.

  The above and other objects and novel features of the present invention will become more apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be described as follows.

  (1) An impact tool according to the present invention includes a motor as a drive source, a spindle to which a rotational force is applied by the motor via a power transmission mechanism, and a spindle that is attached to the spindle and is movable in the direction of the rotation axis of the spindle. A hammer that engages and applies a rotational striking force, an anvil having a square output shaft that is rotated by the rotational striking force of the hammer and that has a square cross-sectional shape across the rotational shaft, and a rectangular output shaft of the anvil that has a socket attachment / detachment mechanism A socket body having a square hole for fitting and mounting via the socket, wherein the socket attaching / detaching mechanism is provided on at least one of the plurality of square surfaces of the rectangular output shaft and the rotation shaft of the output shaft. A groove formed along the direction, an urging elastic body portion disposed in the groove and extending along the groove, and the urging elastic body portion can be elastically deformed. The biasing elastic body portion is fixed to the rectangular output shaft, and the groove and the biasing elastic body portion fit the socket body on the rectangular output shaft. When mounted together, the pressing force based on the elastic deformation in the groove of the urging elastic body is arranged to urge the socket body in the direction opposite to the rotation direction of the rectangular output shaft. It is characterized by that.

  (2) In the impact tool according to the above item (1) according to the present invention, the socket attaching / detaching mechanism includes a locking hole formed in the socket body from the square hole of the socket body toward an outer peripheral surface thereof, A locking elastic body portion comprising an elastic body member disposed in parallel with the biasing elastic body portion along the groove, and having a protrusion that engages with the locking hole in a part thereof; And having the one end side fixed to the rectangular output shaft so that the locking elastic body portion can be elastically deformed, and when the socket body is fitted to the rectangular output shaft, the locking is performed. The protrusions of the locking elastic body portion are engaged with the holes, and when the socket body is released from the rectangular output shaft, the locking elastic body portion is elastically deformed to release the locking body. The engagement between the hole and the protrusion of the locking elastic body portion is released.

  (3) In the impact tool according to the above item (2) according to the present invention, a connection body for operation extending in a direction perpendicular to the rotation axis direction of the rectangular output shaft, continuously to the other end side of the elastic body portion for locking. A portion is provided, and the engagement elastic body portion is elastically deformed by pressing the operation connecting body portion to release the engagement between the engagement hole and the protrusion of the engagement elastic body portion. Features.

  (4) The impact tool according to the present invention is characterized in that two sets of the urging elastic body portions are respectively formed on two opposing surfaces of a plurality of angular surfaces of the rectangular output shaft.

  (5) In the impact tool according to the present invention, the urging elastic body portion is constituted by a belt-like elastic body member.

  (6) In the impact tool according to the present invention, the urging elastic body portion and the locking elastic body portion are integrally formed by a single plate-like elastic body member, and the urging elastic body portion and the engagement member are integrally formed. The stopper elastic body portions are separated from each other by slits in the groove.

  (7) In the impact tool according to the present invention, the urging elastic body part and the fixing elastic part on one end side of the locking elastic body part are fixed to the distal end surface of the rectangular output shaft with a screw. Features.

  (8) In the impact tool according to the present invention, the urging elastic body portion is constituted by a linear elastic body member.

  According to the impact tool as described in the above item (1) of the present invention, the socket attaching / detaching mechanism arranges the urging elastic body portion such as a hold spring along the groove of the square output shaft of the anvil, Further, since the biasing elastic body portion is fixed to the rectangular output shaft, it is possible to easily apply the biasing force in the direction opposite to the rotation direction of the output shaft of the anvil by the pressing action of the biasing elastic body portion. As a result, it is possible to prevent a reduction in impact energy transmission efficiency due to rattling between the anvil and the socket to be fitted.

  According to the impact tool as described in the above section (2) or (3) of the present invention, the socket attaching / detaching mechanism causes the locking elastic body portion to elastically deform the locking elastic body portion. The projection is provided on a part of the socket so that the socket is engaged with or released from the locking hole of the socket body, and the socket is attached or detached. As a result, the attachment and detachment of the socket can be carried out relatively easily, and since there is no need to use a conventional through hole for locking in the anvil, damage due to fatigue failure of the anvil can be prevented.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted.

  FIGS. 1 to 11 are drawings showing an impact tool according to a first embodiment of the present invention, FIG. 1 is a partially broken side view showing the whole impact tool, and FIG. 2 is an enlarged part showing a main part of a socket attaching / detaching mechanism. 3 is a side view of the anvil, FIG. 4 is a partial sectional view of the anvil, FIG. 5 is a plan view of an elastic member in which an urging elastic body portion and a locking elastic body portion are integrally formed, FIG. And FIG. 7 is a side view of the elastic member and a cutaway side view thereof, FIG. 8 is an elevation view of the elastic member, and FIGS. 9 and 10 are cross-sectional views of the structure when the elastic member is fixed to the anvil. FIG. 11 is a partial cross-sectional view of the elastic member and anvil along the line DD in FIG.

  First, the configuration of the impact tool main body will be described with reference to FIG. The impact tool 11 is attached to the spindle 15 to which a rotational force is applied via a power transmission mechanism 14 by a motor 13 as a drive source in the housing 12 of the main body, and the direction of the spindle 15 in the rotation axis direction. A hammer 16 that is movably engaged with each other and that imparts a rotational striking force, and an anvil 18 that is rotated by the rotational striking force of the hammer 16 and that has a square output shaft 17 having a square cross-sectional shape such as a square. In addition, a trigger switch 20 is provided in the handle part (grip part) 19 of the housing 12, and a power cord for connecting to a commercial power outlet extends from the lower part of the handle part 19, although not shown in the figure. Electrical wiring is provided to drive the motor 13 via the trigger switch 20. The motor 13 is driven by a storage battery power source, and the storage battery may be built in the handle portion 19.

  The rotational force of the rotating shaft 22 of the motor 13 is transmitted to the spindle 15 via a power transmission mechanism (planetary gear train) 14 engaged with gear teeth provided at the end of the rotating shaft 22. The power transmission mechanism 14 includes a pinion gear (sun gear) 23 provided on the rotary shaft 22, a plurality of planetary gears 24 that mesh with the pinion gear 23, and an internal gear (ring gear) 25 that meshes with the planetary gear. These are incorporated in the inner cover 21. The spindle 15 has a tip connected to and supported by a hole provided in the center of the anvil 18, and a rear end (right end side in the drawing) is integrated with the planetary gear 24 of the power transmission mechanism 14 and supported by a bearing 28. The spindle 15 is given a rotational force reduced with respect to the rotation of the motor 13 by the power transmission mechanism 14 constituted by the planetary gear 24 and the ring gear 25.

  The anvil 18 is supported by a bearing 27 fixed to the hammer case 26, and holds the detachable socket body 1 via a socket attaching / detaching mechanism described later.

  The hammer 16 is slidable in the axial direction with respect to the ring area surrounding the spindle 15 and the spindle 15, and is urged forward in the axial direction by a spring 29.

  A groove 30 having an inverted V-shaped (substantially triangular) cross-sectional shape is provided on the inner peripheral surface of the hammer 16. The tip surface of the hammer 16 is engaged with the anvil 18 to transmit rotational power to the anvil 18. A striking portion (claw portion) 32 for applying impact torque to the anvil 18 is also provided. On the other hand, a V-shaped cam groove 31 is provided in the axial direction on the outer peripheral surface of the spindle 15, and the hammer 16 is inserted through a steel ball 33 inserted between the cam groove 31 and the groove 30 in the hammer 16. Rotate. At this time, if the rotational torque of the hammer 16 is smaller than the load torque for rotating the bolts and nuts of the object to be tightened, the hammer 16 retreats while compressing the spring 29 along the cam groove 31, The hammer 16 gets over the anvil 18 from the time when the hitting part 32 is separated from the coupling with the anvil 18, and further, the hammer 16 advances while rotating by receiving the bias by the spring 29 and the guide by the cam groove 31. At 32, impact torque is applied to the anvil 18 in front of the rotation. This impact torque is transmitted to the socket body 1, and further, the impact torque is transmitted from the socket body 1 to a fastening member such as a bolt or a nut to perform tightening or release.

  Next, the socket attaching / detaching mechanism according to the present invention will be described. As shown in FIGS. 1 and 2, the socket body 1 itself can have the same structure as described above with reference to FIGS. 26 and 27. Therefore, in the following description of the present invention, the socket body 1 will be described with reference to the same reference numerals for the same parts as those in FIGS. On the front end side of the socket body 1, there is provided a tightening square hole 1d having a square shape such as a hexagonal cross section corresponding to the type of bolt and nut for fastening a fastening member (not shown). Further, the rear end side has an output shaft square hole portion 1b such as a quadrangle to which the square output shaft 17 of the anvil 18 is fitted. As shown in FIGS. 3 and 4, the output shaft 17 of the anvil 18 is provided with a groove portion 17 c for disposing an elastic member (hold spring) 50.

  As shown in FIGS. 5 to 8, the elastic member 50 includes an urging elastic body portion 50b and a locking elastic body portion 50a. Both are processed by press molding and integrally formed by a single plate-like elastic member 50. The elastic member 50 is mechanically separated by a slit (separation groove) 50c into an urging elastic body portion 50b and a locking elastic body portion 50a, and the locking elastic body portion 50a has a protrusion 50d. Is provided. One end portions of the urging elastic body portion 50b and the locking elastic body portion 50a have a shared portion (fixed portion) 50f. The shared portion 50f is connected to the output shaft 17 by a screw 51 through the screw hole 50e. A fixing portion (hold portion) fixed to the screw hole 17d is formed.

  As shown in FIG. 9, the urging elastic body portion 50b and the locking elastic body portion 50a are bent at an angle of 90 degrees or more with respect to the surface of the shared portion 50f. In other words, the angle of the anvil 18 with respect to the rotation axis direction is such that the locking elastic body portion 50a has an angle θ1, and the biasing elastic body portion 50b has an angle θ2 larger than the angle θ1. Both of these are fixed to the tip of the anvil 18 by the screw 51 and are disposed in the groove 17c. As shown in FIG. 2, when the socket body 1 is fitted to the output shaft 17, both the urging elastic body portion 50 b and the locking elastic body portion 50 a are elastically deformed, and the socket body 1 It functions to press the inner peripheral surface of the square hole 1b.

  As shown in FIGS. 10 and 11, when the rectangular hole 1b of the socket body 1 is inserted into the output shaft 17 of the anvil, the urging elastic body portion 50b can be elastically deformed so that the groove 17c of the output shaft 17 can be elastically deformed. Therefore, a pressing force F in the direction of the arrow is applied to the socket body 1. This pressing force F is urged in the direction opposite to the rotation direction of the rectangular output shaft 17. At this time, since the protrusion 50d of the locking elastic body portion 50a of the hold spring 50 engages with the locking hole portion 1a of the socket body 1, the elastic deformation is released and the socket body 1 is moved upward. There is no pressing.

  Therefore, as described above, the socket body 1 is pushed up in the direction of the arrow shown in FIG. 11 by the urging elastic body portion 50b of the hall spring 50, and the locking elastic body portion 50a of the hold spring 50 is the socket. Since 1 is not pushed upward, the socket 1 is biased in the left rotation direction with respect to the right rotation direction of the anvil 18. That is, when the right rotation fastening bolt is used, the socket 1 is urged in the reverse left rotation direction. As a result, even if there is rattling, that is, there is a gap between the rectangular output shaft 17 of the anvil 18 and the rectangular hole 1b of the socket body 1, the rectangular hole 1b is Therefore, the hitting energy can be efficiently transmitted from the anvil 18 to the socket 1.

  FIG. 22 is a characteristic diagram showing a change over time in the torque applied to the nut when the impact tool is struck by bolts and nuts. (A) is a characteristic diagram using the impact tool according to the first conventional example, and (b) is a characteristic diagram of the impact tool according to the present invention. According to the present invention, conventionally, the maximum torque value was bisected in a relatively long time, but according to the present invention shown in (b), a single shot larger than the conventional torque in a relatively short time. Torque and stable tightening torque could be obtained. Compared with the conventional one, about 20 to 30% of power loss can be prevented.

  According to the present invention, since the protrusion 50d provided on the locking elastic body 50a of the hold spring 50 is engaged with the locking hole (through hole) 1a of the socket 1, the impact tool During use, the socket 1 does not fall off or leave the anvil 18. Further, an operation connecting body portion 50g is provided at an end of the latching elastic body portion 50a of the hold spring 50, and the operation spring body 50g is pushed down in the direction of the arrow 52 shown in FIG. The engagement between the projection 50d provided on the 50 locking elastic body 50a and the locking hole (through hole) 1a of the socket body 1 is released, and the socket 1 can be easily attached and detached.

  Next, a socket attaching / detaching mechanism according to a second embodiment of the present invention will be described with reference to FIGS. Two pairs (two sets) of the biasing elastic body portion 50b and the locking elastic body portion 50a of the hold spring 50 described above are set to a rotational position of 180 degrees around the screw hole 50e, that is, a point-symmetrical position. Can be arranged in one piece. That is, as shown in FIGS. 12 to 14, a single elastic member (hold spring) 50 is biased with two slits 50c and two locking elastic members 50a having projections 50d. The elastic body portion 50b is provided in two places. Then, as shown in FIG. 16, two groove portions 17 c are provided in two opposing outer peripheral surfaces of the rectangular output shaft 17, and the holding spring 50 is fixed to the front end surface of the rectangular output shaft 17 by screws 51. The elastic body portion 50a and the urging elastic body portion 50b are disposed in the groove portions 17c on each surface. As a result, the urging of the socket 1 in the counterclockwise rotation direction with respect to the anvil 18 is made stronger and reliable, while the socket 1 is prevented from falling off the anvil 18.

  17 to 21 show a third embodiment of the present invention. The hold spring 50 acting as the urging elastic body portion 50b is a linear elastic body member, and the urging elastic body portion 50b is formed so as to spread outward as it goes to the end. A locking projection 50h for fixing to the rectangular output shaft 17 is provided at the end so as to protrude inward. Further, the square output shaft 17 is provided with a groove portion 17c in which the elastic body portion 50b for urging the hold spring 50 is disposed, and a locking groove portion 17e in which the projection portion 50h is locked, so that the left side with respect to the anvil 18 is provided. The socket 1 is urged in the rotational direction. Further, in the loosening operation of the right rotation bolt and the tightening operation of the left rotation bolt, the transmission loss of impact energy can be prevented by urging the socket 1 in the right rotation direction with respect to the anvil 18. In order to reverse the bias, the shape of the hold spring 50 can be changed by reversing the left and right.

  As described above, according to the present invention, since the shakiness between the socket and the anvil is eliminated, it is possible to prevent the transmission of impact energy from being reduced, and the socket can be attached and detached with a simple operation.

The fragmentary sectional view of the impact tool concerning a 1st embodiment of the present invention. The principal part expanded fragmentary sectional view of the socket attachment / detachment mechanism which concerns on the 1st Embodiment of this invention. The side view of the anvil which concerns on the 1st Embodiment of this invention. FIG. 4 is a partial cross-sectional view of the anvil along the line BB in FIG. 3. The top view of an elastic body member provided with the elastic body part for urging | biasing which concerns on the 1st Embodiment of this invention, and the elastic body part for latching. The side view of the elastic body member shown by FIG. The fracture | rupture side view of the elastic body member shown by FIG. FIG. 6 is an elevation view of the elastic member shown in FIG. 5. FIG. 6 is a structural cross-sectional view when the elastic body member shown in FIG. 5 is fixed to an anvil. The principal part expanded sectional view of the socket attachment / detachment mechanism which concerns on the 1st Embodiment of this invention. Sectional drawing which follows the DD line of FIG. The side view of the elastic body member which concerns on the 2nd Embodiment of this invention. The top view which concerns on the 2nd Embodiment of this invention. Sectional drawing which follows the DD line of FIG. Sectional drawing of the principal part of the socket attachment / detachment mechanism which concerns on the 2nd Embodiment of this invention. FIG. 16 is a cross-sectional view of FIG. 15. The top view of the elastic body member which concerns on the 3rd Embodiment of this invention. The elevational view of the elastic member shown by FIG. Sectional drawing of the principal part of the socket attachment / detachment mechanism which concerns on the 3rd Embodiment of this invention. FIG. 20 is a cross-sectional view of FIG. 19. Sectional drawing of the principal part of the socket attachment / detachment mechanism which concerns on the 3rd Embodiment of this invention. It is a characteristic view showing the time change of torque, (a) is a characteristic view of a conventional example, (b) is a characteristic view of the present invention. Sectional drawing of the socket attachment / detachment mechanism of the impact tool which concerns on a prior art example. FIG. 24 is a cross-sectional view taken along line AA of FIG. The side view of the anvil of the impact tool which concerns on a prior art example. Sectional drawing of the socket main body of the impact tool which concerns on a prior art example. The side view of the socket main body of the impact tool which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Socket body (socket) 1a Locking hole (through hole) 1b Square hole 1c Ring peripheral groove 1d Fastening square hole 2 Elastic ring 4 Conventional impact tool main body 5 Conventional anvil 5a Locking hole Part (through hole) 5b Conventional square output shaft 6 Cylindrical pin 11 Impact tool of the present invention 12 Impact tool body (housing)
DESCRIPTION OF SYMBOLS 13 Motor 14 Power transmission mechanism 15 Spindle 16 Hammer 17 Anvil square output shaft 17c Installation groove 17d Screw hole 17e Locking hole 18 Anvil 19 Handle portion 20 Trigger switch 21 Inner cover 22 Motor rotation shaft 23 Pinion gear (sun gear) 24 planetary gear 25 internal gear (ring gear) 26 hammer case 27 hammer case bearing 28 planetary gear bearing 29 spring 30 reverse V-shaped groove 31 cam groove 32 striking part (claw part) 33 steel ball 50 elastic body member (hold spring) 50a Locking elastic body portion 50b Energizing elastic body portion 50c Slit (groove for separation) 50d Projection portion 50e Screw hole 50f Shared portion (fixing portion) 50g Operation connecting body portion 50h Locking projection portion 51 Screw 52 Arrow F pressing force

Claims (12)

  A motor serving as a drive source, a spindle to which a rotational force is applied by the motor via a power transmission mechanism, and a hammer that is attached to the spindle and is movably engaged in the direction of the rotation axis of the spindle to provide a rotational impact force And an anvil having a rectangular output shaft that is rotated by the hammering force of the hammer and has a square cross-sectional shape across the rotational axis, and a corner for fitting and mounting the rectangular output shaft of the anvil via a socket attaching / detaching mechanism A socket body having a hole, wherein the socket attaching / detaching mechanism includes a groove formed along at least one of the plurality of square surfaces of the rectangular output shaft along the rotation axis direction of the output shaft; An urging elastic body portion disposed in the groove and extending along the groove, and one end side of the urging elastic body portion so that the urging elastic body portion can be elastically deformed A fixing portion that is fixed to the rectangular output shaft, and the groove and the biasing elastic body portion of the biasing elastic body portion when the socket body is fitted and mounted on the rectangular output shaft. An impact tool, wherein a pressing force based on elastic deformation in the groove is arranged so as to urge the socket body in a direction opposite to a rotation direction of the rectangular output shaft.   The socket attaching / detaching mechanism includes a locking hole formed in the socket body from the square hole of the socket body toward an outer peripheral surface thereof, and in parallel with the urging elastic body portion along the groove. A locking elastic body portion having a protruding portion that engages with the locking hole, the locking elastic body portion being elastically deformable. The one end side is fixed to the rectangular output shaft so that when the socket body is fitted and mounted on the rectangular output shaft, the protruding portion of the locking elastic body portion is engaged with the locking hole. On the other hand, when the socket main body is released from the rectangular output shaft, the locking elastic body is elastically deformed to engage the locking hole and the protrusion of the locking elastic body. The impact tool according to claim 1, wherein the impact tool is released.   An operation connecting body portion extending in a direction perpendicular to the rotation axis direction of the rectangular output shaft is provided continuously to the other end side of the locking elastic body portion, and the locking connection portion is pressed by the operation connecting body portion. The impact tool according to claim 2, wherein the elastic body portion is elastically deformed to release the engagement between the locking hole and the protruding portion of the locking elastic body portion.   The two sets of the urging elastic body portions are formed on two opposing surfaces of a plurality of square surfaces of the rectangular output shaft, respectively. Impact tool.   The impact tool according to any one of claims 1 to 4, wherein the urging elastic body portion is constituted by a belt-like elastic body member.   The urging elastic body part and the locking elastic body part are integrally formed by a single plate-like elastic body member, and the urging elastic body part and the locking elastic body part are formed in the groove. 6. The impact tool according to claim 2, wherein the impact tool is separated from each other by a slit.   7. The fixing portion on one end side of the urging elastic body portion and the locking elastic body portion is fixed to a distal end surface of the rectangular output shaft with a screw. The impact tool described in one.   The impact tool according to claim 1, wherein the urging elastic body portion is constituted by a linear elastic body member.   A motor serving as a drive source, a spindle to which a rotational force is applied by the motor via a power transmission mechanism, and a hammer that is attached to the spindle and is movably engaged in the direction of the rotation axis of the spindle to provide a rotational impact force And an anvil having a rectangular output shaft that is rotated by the hammering force of the hammer and has a square cross-sectional shape across the rotational axis, and a corner for fitting and mounting the rectangular output shaft of the anvil via a socket attaching / detaching mechanism A socket body having a hole, wherein the socket attaching / detaching mechanism includes a locking hole formed in the socket body from the square hole of the socket body toward an outer peripheral surface thereof, A groove formed on at least one of a plurality of rectangular surfaces of the rectangular output shaft along the rotation axis direction of the output shaft, and an elastic member disposed along the groove. A locking elastic body portion having a protrusion that engages with the locking hole in a part thereof, and the locking elastic body portion so that the locking elastic body portion can be elastically deformed. A fixing portion for fixing one end side of the socket to the rectangular output shaft, and when the socket body is fitted to the rectangular output shaft, the protruding portion of the locking elastic body portion is engaged with the locking hole. On the other hand, when the socket body is unfitted to the rectangular output shaft, the locking elastic body is elastically deformed to engage the locking hole and the protrusion of the locking elastic body. Impact tool characterized by releasing   An operation connecting body portion extending in a direction perpendicular to the rotation axis direction of the rectangular output shaft is provided continuously to the other end side of the locking elastic body portion, and the locking connection portion is pressed by the operation connecting body portion. The impact tool according to claim 9, wherein the elastic body portion is elastically deformed to release the engagement between the locking hole and the protrusion of the locking elastic body portion.   Two sets of the locking elastic body portions are respectively formed on two opposing surfaces of a plurality of square surfaces of the rectangular output shaft, and two sets of the locking holes are opposed to the socket body. The impact tool according to claim 9, wherein the impact tool is formed on two inner peripheral surfaces. The impact tool according to claim 11, wherein the two sets of locking elastic body portions are integrally formed of a plate-like elastic member.

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