JP2001310271A - Tool holding device for impact tools - Google Patents

Abstract

(57) Abstract: The present invention relates to a tool holding device for an impact tool, and an object thereof is to improve the operability of the device. A rotating torque is applied to the holder by a torsion spring so that the holder is always located at a position where the holder moves in a radial direction, and a rotation amount of the holder is provided on the front cover. By limiting the groove 2b and the protrusion 6b of the holder 6, the structure is not affected by intrusion of dust or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool holding device for holding a tip tool of an impact tool such as an electric hammer and a hammer drill.

[0002]

2. Description of the Related Art As a conventional tool holding device for an impact tool, there is one as disclosed in Japanese Patent Application Laid-Open No. 9-11155. Hereinafter, a conventional tool holding device for an impact tool will be described with reference to FIGS. FIG. 3 is a longitudinal sectional side view of a conventional tool holding device for an impact tool, and FIG.
FIG. 5 is a sectional view taken along line CC of FIG. 3.

[0003] The tool holding device for an impact tool basically holds the locking tool 3 by engaging the locking member 3 with the small diameter portion 1 a of the tip tool 1. Therefore, in order to exchange the tip tool 1, it is necessary to make the locking member 3 movable in the radial direction. The locking member 3 is arranged in holes 2a provided at several places (three places in the figure) on the front cover 2 in a non-rotating state with respect to the main body. ,
Further, a convex portion is also formed on the outer wall of the locking member 3, and these convex portions are engaged with each other, so that even if the tip tool 1 is not present, the locking member 3 is located inside the front cover 2. It is configured not to fall.

A grip 7 is fitted around the outer periphery of the holder 6, and a damper 8 and a plate 9 are provided at the upper end of the holder 6 to absorb a shock in the tool axis direction. A shaft C retaining ring 10 is disposed to prevent the ring from coming off.

The movement of the locking member 3 in the radial direction is restricted by the holder 6 located on the outer periphery thereof. FIG. 4 shows a state in which the holder 6 restricts the radial movement of the locking member 3 so that the holder 6 does not move in the radial direction when the holder 6 comes into contact with the outer periphery of the locking member 3. That is, the state shown in FIG. 4 is a state in which the tip tool 1 is prevented from coming off. When the holder 6 is rotated approximately 45 degrees from the state shown in FIG. 4, a groove 6 provided inside the holder 6 is formed on the outer periphery of the locking member 3.
c is located, and the locking member 3 can be moved in the radial direction, so that the tip tool 1 can be replaced.

The locking member 3 is always attached to the front cover 2.
A locking portion 6 e provided adjacent to the groove 6 c of the holder 6, and a locking member 3.
Engages to restrict the holder 6 from rotating only approximately 45 degrees.

[0007] The rotation position of the holder 6 configured as described above is regulated by the engagement between the steel ball 11 provided on the holder 6 and the conical groove 2 c provided on the front cover 2. The holder 6 is provided with a through hole 6 d having a diameter slightly larger than the steel ball 11, and the steel ball 11 having a diameter larger than the thickness of the holder 6 is inserted into the through hole 6 d. A C-shaped leaf spring 12 is provided on the outer periphery of the steel ball 11 and the holder 6,
Due to this C-shaped leaf spring 12, an inward force always acts on the steel ball 11. Since the steel ball 11 has a diameter larger than the thickness of the holder 6, when the steel ball 11 comes to the position of the conical groove 2 c provided in the front cover 2, the steel ball 1 is pressed by the spring pressure of the C-shaped leaf spring 12.
1 is embedded in the conical groove 2c, whereby the rotation of the holder 6 is restricted. The state shown in FIG. 5 shows the engagement state between the steel ball 11 and the conical groove 2c in a state where the movement of the locking member 3 in the radial direction is restricted (the state shown in FIG. 4). The conical groove 2c also exists at a position shifted by approximately 45 degrees in addition to the conical groove 2c engaged with the steel ball 11 in FIG. The operator rotates the grip 7 integrally formed with the holder 6 with a force larger than the rotation stop torque (engagement force between the steel ball 11 and the conical groove 2c) by the C-shaped leaf spring 12 shown in FIG. Then, the steel ball 11 leaves the conical groove 2c against the C-shaped leaf spring 12. Further, when the operator rotates the grip 7, the holder 6 rotates, and the conical groove 2c located at the shifted position and the steel ball 11 are engaged. This state is a state in which the groove 6c is present on the outer periphery of the locking member 3 in FIG. 4 and the locking part 6e is in a position where it comes into contact with the locking member 3, so that the steel ball 11 has two conical grooves. Movement is possible only between 2c.

[0008]

In the above-mentioned conventional tool holding device, when dust such as concrete enters the conical groove of the front cover or the hole provided in the holder, the sliding resistance of the steel ball increases, and There has been a problem that the turning torque of the holder becomes large and the operability at the time of attaching and detaching the tip tool is deteriorated.

It is an object of the present invention to provide a tool holding device which eliminates the above-mentioned disadvantages of the prior art and has good operability.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotary torque to a holder by a torsion spring so that the holder is always located at a position for locking the radial movement of a locking member. The amount of rotation is limited by the groove provided in the front cover and the protrusion of the holder, and is achieved by a structure which is not affected by intrusion of dust and the like.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a tool holding device for an impact tool according to the present invention will be described below with reference to FIGS.

The relationship among the tip tool 1, the front cover 2, the locking member 3, the front sleeve 5, the holder 6, the grip 7, the damper 8, the plate 9, and the shaft C retaining ring 10 is the same as in the prior art. Is omitted here.

In this embodiment, the torsion spring 4 is disposed between the front sleeve 5 and the holder 6. The function of the torsion spring 4 is to apply a turning torque to the holder 6. Therefore, the torsion spring 4 does not necessarily need to have an axial spring force.

Arms 4a are provided at both ends of the torsion spring 4,
One arm 4 a of the torsion spring 4 is inserted into a hole 5 a of the front sleeve 5, and the other arm 4 a is inserted into a hole 6 a of the holder 6. In this embodiment, the length of the arm portion 4a is set to an optimum length by an assembling method described later in order to prevent the torsion spring 4 from generating an axial spring force.

On the other hand, the holder 6 is provided with a plurality (three in this embodiment) of projecting portions 6b protruding inward, and is engaged with grooves 2b provided on the outer periphery of the front cover 2. Accordingly, the grooves 2b also correspond to the protrusions 6b, and therefore are provided in the same number as the number of the protrusions 6b. The groove 2b is open in the tip direction (left direction in FIG. 1), and has a circumferential length that allows the protrusion 6b to rotate approximately 50 degrees within one groove 2b. I have. With such a configuration, the holder 6 can rotate in a range of approximately 50 degrees with respect to the front cover 2. Front cover 2 and holder 6
2 is maintained unless the operator turns the holder 6 via the grip 7, that is, the state in which the radial movement of the locking member 3 is regulated by the holder 6. It has become. To maintain this state, the torsion spring 4 is given an initial rotation torque. The initial rotation torque is a torque for further rotating the holder 6 in the counterclockwise direction in the state of FIG. 2. Even if the initial rotation torque applies a rotational vibration to the entire tool, for example, 2 can be maintained. In this embodiment, in order to prevent the initial rotation torque from being applied to the locking member 3, the projection 6b is configured not to abut the locking member 3 but to abut both side walls of the groove 2b. ing. In this embodiment, the torsion direction of the torsion spring 4 is set such that when the holder 6 is rotated clockwise from the state of FIG. However, this may be twisted in the opposite direction so that the screw diameter increases when the holder 6 is rotated.

The groove 2b of the front cover 2 is formed by cold forging, and the protrusion 6b of the holder 6 is formed.
Is also formed by cold forging. In the present embodiment, the projections 6b can be formed integrally with the holder 6 by molding by cold forging, thereby reducing the number of parts. Absent.

A gap is provided between the groove 2b of the front cover 2 and the projection 6b of the holder 6 so that dust such as concrete cannot be accumulated. The dust passing through the gap is removed from between the front sleeve 5 and the grip 7. It has a structure that can be released to the outside of the tool holding device.

Next, a method of assembling the tool holding device of the impact tool according to the present embodiment will be described.

First, the front sleeve 5 is inserted around the front cover 2 attached to the impact tool. At this time, since the front sleeve 5 is configured so as not to rotate with respect to the front cover 2, the rotation is prevented only by inserting the front sleeve 5 into the front cover 2. After the front sleeve 5 is inserted, a retaining ring is attached to the Freon and the cover 2 to prevent the front sleeve 5 from coming off (restriction of axial movement).

Next, one arm 4a of the torsion spring 4 is inserted into the hole 5a of the front sleeve 5, and the locking member 3 is further inserted.
Is inserted into the hole 2a and the holder 6 is inserted over the front cover 2 from the front end of the shaft. With the holder 6 inserted into the front cover 2 to some extent, the other arm 4 a of the torsion spring 4 is inserted into the hole 6 a of the holder 6.
When the arm 4a of the torsion spring 4 is inserted into the groove 6a, the position of the hole 6a is determined if the torsion spring 4 is not slightly twisted.
Are not positioned in the hole 6a. The torsion of the torsion spring 4 generates the above-described initial rotation torque. The arm 4a of the torsion spring 4 is aligned with the position of the hole 6a, and the holder 6 is further moved rightward in FIG. 1 so that the arm 4a is inserted into the hole 6a. At this time, in order to prevent the torsion spring 4 from generating an axial spring force,
It is desirable that the arm 4a and the hole 6a have a sufficient length.

Finally, the grip 7 and the damper 8 are inserted from the front end of the shaft, and the shaft C retaining ring 10 is attached to prevent the components from coming off.

As described above, the tool holding device of this embodiment can be assembled. However, since all the components are assembled by being inserted from the tip of the shaft, the tool holding device has a very excellent assemblability. .

The operation of the tool holding device thus assembled will be described.

When the operator mounts or removes the tip tool 1, a grip 7 integrally formed with the holder 6 is used.
Is rotated clockwise in FIG. 2 against the torsion spring 4. When rotated about 50 degrees, the protrusion 6b of the holder 6
Abuts against the inner wall of the groove 2a, and cannot rotate any more. At that position, the groove 6c is present on the outer periphery of the locking member 3, so that the locking member 3 can be moved in the radial direction,
The locking force of the tool bit 1 is lost, and the operator can mount or remove the tool bit 1. When the attaching or detaching operation of the tip tool 1 is completed, the operator simply releases the grip 7 held, and the holder 6 returns to the original position by the action of the torsion spring 4.

In the present embodiment, the operator operates the tip tool 1
When performing the attachment or detachment, the operator needs to hold the grip 7 against the torsion spring 4, but if necessary, a configuration capable of maintaining the grip 7 in a rotated state is added. Is also good.

[0026]

According to the present invention, a rotational torque is applied to the holder by a torsion spring so that the holder is always located at a position where the radial movement of the locking member is locked. A tool holding device with good operability can be provided by using a structure that is limited by the groove provided in the cover and the protrusion of the holder and is not affected by intrusion of dust or the like.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing an embodiment of a tool holding device for an impact tool according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a longitudinal sectional side view of a conventional tool holding device for an impact tool.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a sectional view taken along line CC of FIG. 3;

[Explanation of symbols]

In the drawing, 1 is a tip tool, 1a is a small diameter portion, 2 is a front cover, 2a is a hole, 2b is a groove, 2c is a conical groove, 3
Is a locking member, 4 is a torsion spring, 4a is an arm, 5 is a front sleeve, 5a is a hole, 6 is a holder, 6a is a hole, 6
b is a projection, 6c is a groove, 6d is a through hole, 6e is a locking part, 7 is a grip, 8 is a damper, 9 is a plate, 10 is a C-ring, 11 is a steel ball, and 12 is a C-shaped leaf spring. It is.

Claims (3)

[Claims] 1. A front cover for accommodating a tip tool that performs an impact motion, and a front cover is provided so as to be radially movable in a hole provided in the front cover, and regulates and releases the axial movement of the tip tool. In a tool holding device for an impact tool having a locking member and a holder for restricting and releasing a radial movement of the locking member by a rotation operation, the holder holds one end of a torsion spring, and rotates the holder. A tool holding device for an impact tool, wherein a torsion force is generated in the torsion spring by an operation, and the torsion force causes the position of the holder to act on a position for restricting a radial movement of the locking member. 2. A protrusion is provided on an inner peripheral side of the holder, and a groove having a predetermined length is provided on an outer periphery of the front cover in a circumferential direction, and the groove is engaged with the protrusion.
2. A tool holding device for an impact tool according to claim 1, wherein a rotation range of said holder is regulated. 3. The front end of the groove provided on the outer periphery of the front cover is open.
A tool holding device for the impact tool according to the above.