JP2002219668A - Driving tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability and usability of a housing and surely prevent the idle driving by efficiently mitigating an impact force. SOLUTION: A tool holder 14 is formed of a cylindrical holder body 15 having a rear part 15a loosely inserted in a barrel 2, a separate-body flange 19 externally fitted to the rear part 15a, and a rubber sleeve 21 externally fitted to the rear part 15a between the barrel 2 and the holder body 15 and regulating the rearward movement with its abutting on the flange 19. A rubber ring 26 is interposed between the head part 23a of the bolt 23 and the flange 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a striking tool such as an electric hammer having a tool holder into which a bit can be inserted at the front end of a housing.

[0002]

2. Description of the Related Art In an electric hammer, for example, a cylinder is provided in a cylindrical housing, and a piston which moves forward and backward by a motor drive and a striker interlocked with the piston via an air chamber are provided in the cylinder. Further, a meson is accommodated in the housing in front of the striker so as to be movable back and forth. On the other hand, a flange of a cylindrical tool holder into which a bit can be inserted is fixed to the front end of the housing with a bolt from the front, and when the bit is inserted into this tool holder, the meson pushed by the bit moves to the front of the cylinder. Stop at a predetermined position. Therefore, when the motor is driven with the bit inserted, the piston moves forward and backward, causing the striker to advance and retreat at a predetermined stroke, causing the striker to strike the meson, and transmitting the striking force to the bit via the meson. Will be communicated.

[0003]

During the above-mentioned striking operation, the impact force generated by the bit and the meson is transmitted to the housing via the tool holder, so that the durability of the housing is reduced or the operator is discomforted. In addition to this, the bolt may be loosened. On the other hand, if the bit is not inserted or the tip of the bit is not pressed against the ground, etc., the meson projects forward and separates from the striker with the first strike of the striker, and the striker thereafter Even if it moves forward and backward, it does not come into contact with the meson, so that an idle shot is prevented. However, the protruding meson may bounce backward with the force of contacting the tool holder at the time of the first idle hit, and may again be allowed to hit by the hitter, and the hit hit is not sufficiently prevented.

Accordingly, an object of the present invention is to provide a striking tool capable of effectively mitigating an impact force to improve the durability and feeling of use of a housing and also to reliably prevent a blank hit. It is intended for.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a tool holder is provided with a cylindrical holder body whose rear part can be loosely inserted into a housing, and a tool holder provided with a front part. A separate flange that is mounted in a movement-restricted state and a ring-shaped part that is positioned between the housing and the holder body and that is mounted on the rear part behind the flange and that is restricted from moving backward when in contact with the flange. And a second buffer member is interposed between the head of the bolt and the flange. In addition to the object of the first aspect, the invention according to claim 2 further includes the step of attaching the flange to the bolt so that the bolt tightening torque required for fixing the flange can be secured even if the second buffer member is used. Sleeves that penetrate and contact the bolt head and the front end of the housing, respectively, are provided.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial longitudinal sectional view of the electric hammer. The electric hammer 1 has a cylinder 3 coaxially fixed to the rear (right side in the figure) inside a cylindrical barrel 2 as a housing. A piston 4 is provided inside which is reciprocated in the axial direction from the rotation of a motor (not shown) via a crank mechanism. A striker 6 as a striker is provided in front of the piston 4 via an air chamber 5 in the axial direction. It is stored so that it can move back and forth. In addition, in front of the cylinder 3 in the barrel 2, a large diameter portion 8 is provided at the front as a meson.
Two-stage shaft-shaped impact bolt 7 with small diameter portion 9 at the rear
Are accommodated so as to be able to move back and forth in the axial direction. Further, between the impact bolt 7 and the cylinder 3, iron rings 10, 11 and rubber rings 12 into which only the small diameter portion 9 can be loosely inserted.
Are slidably accommodated, and the front iron ring 10 is urged by a coil spring 13 provided outside the cylinder 3 to a position where the iron ring 10 comes into contact with a tool holder 14 described later.

The tool holder 14 is a cylindrical body coaxially mounted on the front end of the barrel 2 and, as shown in FIG.
A two-stage hole is formed with a small-diameter hole 16 in which the large-diameter portion 7 can be loosely inserted and a large-diameter hole 17 in which the large-diameter portion 8 of the impact bolt 7 can be loosely inserted. The formed holder main body 15, a flange 19 which is separately provided on a rear part 15 a of the holder main body 15, and a rear part 15 a
And a rubber sleeve 21 as a first cushioning member which is separately packaged. First, the flange 19 has a disk shape whose front position is regulated by abutting against a stopper 18 protruding from the outer periphery of the holder body 15, and has a cylinder located on the inner diameter side between the barrel 2 and the rear portion 15 a. The shape part 20 is extended. Next, the rubber sleeve 21 has the same inner and outer diameters as the cylindrical portion 20 of the flange 19 between the barrel 2 and the rear portion 15a, and abuts the rear end of the cylindrical portion 20 forward, while moving backward. The cylindrical portion 20 and the ring stopper 2 come into contact with a ring stopper 22 screwed around the rear end of the rear portion 15a.
2 is restricted from moving in the axial direction.

Thus, the flange 19 and the rubber sleeve 21
Is inserted from the front of the barrel 2 and the flange 19 is connected to a plurality of bolts 23, 23,.
By screwing to the front end of the barrel 2 with the
Is made. However, each bolt 23 is provided with a sleeve 24 that penetrates through the flange 19 and abuts on the head 23 a of the bolt 23 and the front end of the barrel 2, respectively. 24, a rubber ring 2 having a square cross section as a second cushioning member.
6 is exterior. Therefore, the flange 19 is pressed and fixed to the front surface of the barrel 2 via the rubber rings 26, 26,... By the sleeves 24, 24,. Here, sleeve 2
The reason for using 4 is to obtain a tightening torque required for fixing the flange 19 at each bolt 23.

Reference numeral 27 denotes a bit, which is a tool holder 1
4, the tool retainer 29 is orthogonally inserted into the tool holder 14 at the position of the cutout 28 formed at the upper intermediate portion, so that the bit 27 is attached to the rear end of the cutout 28 by the tool retainer 29. The tool retainer 29 can be moved in the axial direction between a forward position where the tool 29 abuts and a retracted position where the tool retainer 29 abuts the front end of the cutout 28. The bit 2 that has entered the large-diameter hole 17 of the tool holder 14 earlier than the contact
7 enters the bottomed hole 30 recessed in the large diameter portion 8 of the impact bolt 7, retreats the impact bolt 7, and connects the iron rings 10, 11 and the rubber ring 12 to the cylinder 3.
Retract until it touches. At this pushed position, the small diameter portion 9 of the impact bolt 7 projects into the cylinder 3.

In the electric hammer 1 constructed as described above, when the bit 27 is inserted into the tool holder 14 and its tip is pressed against the ground or the like, the bit 27 is retracted and the impact bolt 7 is pushed to the pushing position as described above. Retreat. Therefore, when the motor is driven to move the piston 4 forward and backward, the striker 6 moves forward and backward in conjunction with the air spring action of the closed air chamber 5, and strikes the small diameter portion 9 of the impact bolt 7 at the time of forward movement. . Therefore, the impact force is transmitted to the bit 27 that comes into contact with the impact bolt 7 via the impact bolt 7. Here, the impact force due to the impact operation is also transmitted to the tool holder 14 via the impact bolt 7 and the bit 27, but since the rubber sleeve 21 is interposed between the tool holder 14 and the barrel 2, the 2 is smaller. Similarly, the impact force is transmitted to the bolt 23, but the impact force transmitted to the bolt 23 is small because the rubber ring 26 is interposed between the bolt 23 and the flange 19.

When the bit 27 is pulled out of the tool holder 14 or the tip of the bit 27 is separated from the ground or the like, the impact bolt 7
When the striker 6 moves forward and strikes the impact bolt 7 (blank hit), the impact bolt 7 moves forward with that momentum. Therefore, as shown in FIGS. 1 and 2, the small-diameter portion 9 of the impact bolt 7 is separated from the cylinder 3, so that the striker 6 does not come into contact with the impact bolt 7 even if the striker 6 moves forward, and the subsequent hitting is prevented. In particular, here, even if the impact bolt 7 which has advanced has collided with the bottom of the large-diameter hole 17, the impact at the time of collision of the impact bolt 7 is reduced by the elasticity of the rubber sleeve 21 and the rubber ring 26 of each bolt 23. , The impact bolt 7 has less rebound, and the small-diameter portion 9 is
It does not protrude inside.

As described above, according to the above-described embodiment, the tool holder 14 includes the holder main body 15 whose rear portion 15a can be freely inserted into the barrel 2, and the separate flange 19 that is externally provided on the rear portion 15a of the holder main body 15. A rubber sleeve 21 is provided between the barrel 2 and the rear portion 15a, and is provided on the rear portion 15a, and is restricted from moving rearward in a contact state with the flange 19, while the head 23a of the bolt 23 is With the rubber ring 26 interposed between the flange 19 and the flange 19, the impact force transmitted to the barrel 2 and the bolt 23 during the impact operation can be effectively reduced. Therefore, it is possible to improve the durability of the barrel 2 and the feeling of use of the operator, and to prevent the bolt 23 from being loosened. In addition, it is possible to prevent the impact bolt 7 from rebounding in a state where the bit 27 is not provided or in a state where the impact bolt 7 is not pressed against the ground or the like, so that it is possible to surely prevent the idle hit. Furthermore, the bolt 23
Since the sleeves 24 that penetrate the flange 19 and abut on the head 23a of the bolt 23 and the front end of the barrel 2 are provided, the tightening torque of the bolt 23 required for fixing the flange 19 even with the rubber ring 26 is used. Can be secured.

The first cushioning member is not limited to the rubber sleeve 21 but may be an O-ring. In this case, the number of the first cushioning member is not limited to one, and a plurality of members may be arranged in the axial direction. The same applies to the second cushioning member. A plurality of O-rings may be provided in the axial direction to improve the elasticity.
The sleeve 24 is not always necessary if the necessary tightening torque is obtained for the bolt.

[0014]

According to the first aspect of the present invention, the tool holder is formed by the holder main body, the flange separate from the holder main body, and the first buffer member, while the head of the bolt and the flange are connected to each other. By interposing the second buffer member therebetween, it is possible to effectively reduce the impact force transmitted to the housing and the bolt during the impact operation. Therefore, the durability of the housing and the usability of the worker can be improved, and the loosening of the bolt can be prevented. In addition, the bounce of the meson in a state where there is no bit or a state where the meson is not pressed against the ground or the like can be suppressed, so that it is possible to reliably prevent the blank hit. According to the second aspect of the present invention, in addition to the effect of the first aspect, the second cushioning member is provided by providing the bolt with sleeves that penetrate the flange and abut on the bolt head and the housing front end, respectively. Even with the use of, the bolt tightening torque required for fixing the flange can be secured.

[Brief description of the drawings]

FIG. 1 is a partial vertical cross-sectional view of an electric hammer (in an idling prevention state).

FIG. 2 is an enlarged sectional view of a tool holder part in FIG.

[Explanation of symbols]

1. Electric hammer, 2. Barrel, 3. Cylinder, 4
..Piston, 6 striker, 7 impact bolt, 14 tool holder, 19 flange, 21
..Rubber sleeve, 23..bolt, 26..Rubber ring, 27..bit

Claims (2)

[Claims] 1. A tool holder in which a bit can be inserted is coaxially disposed in front of a cylindrical housing, and a flange provided around the tool holder is screwed to a front end of the housing with a bolt from the front. On the other hand, a piston provided in the housing is provided with a piston which moves forward and backward, and a striker which moves forward and backward with a predetermined stroke through an air chamber in front of the piston. In front of the child, a meson supporting the rear end of the bit inserted in the tool holder is housed, and the hitter is hit by the hitter with the advance and retreat of the piston, so that a hitting operation is performed on the bit. A transmitting tool capable of transmitting the tool holder, wherein the tool holder has a cylindrical holder main body whose rear portion can be loosely inserted into the housing, and a forward movement restricted state of the holder main body. A separate flange to be provided, and a ring-shaped second member which is provided between the housing and the holder main body, is provided at the rear portion behind the flange, and is restricted from moving rearward in a contact state with the flange. 1 between the bolt head and the flange.
A striking tool characterized by interposing a buffer member. 2. The hitting tool according to claim 1, wherein the bolt is provided with sleeves that penetrate a flange and respectively contact the bolt head and the front end of the housing.