JPH0619848Y2 - Locking structure for impact tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a loosening prevention device for an impact power tool.

[Conventional technology]

As a slack preventive device for impact moving tools
There is one described in Japanese Patent No. 0.

The device described in this publication integrally connects a cylinder of an impact tool, a handle cap at its upper end, and a chisel holder at its lower end with a plurality of through bolts.

In this conventional example, the lower end of the through bolt is fixed to the chisel holder by some means, and a nut screwed into the male screw of the through bolt protruding above the handle cap is provided with a loosening stopper.

That is, a nut is screwed into a male screw on a through bolt that protrudes above the handle cap, and a washer-shaped stopper having a polygonal hole that fits the outside of the polygonal shape of this nut is used to utilize the polygonal hole. Non-rotatably fit on the outside of the nut.

The stopper is not rotatable with respect to the handle cap through the engagement of the engaging portion on the outside and the engaging portion of the handle cap.

[Problems to be solved by the device]

In the case of the above-described conventional locking device, the lower end of the through bolt is not rotatable with respect to the chisel holder, and the nut screwed into the male screw at the upper end is not rotatable with respect to the handle cap.

However, before screwing in the nut,
Except for the lower end, the length is very long with respect to the diameter, and when the nut is tightened, the shaft portion of the bolt is twisted, so that it is difficult to obtain an appropriate tightening force.

When a twist is introduced into the through bolt in this way, the through bolt overcomes the friction torque between the nut and the bearing surface and returns, and because the bolt is used for a long time with the twist occurring, There was a problem that the durability of the

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide an anti-loosening device for an impact power tool in which a twist is not introduced into a bolt.

[Means for Solving the Problems]

In order to achieve the above object, the present invention comprises a cylinder,
It consists of a handle cap at its upper end, a chisel holder at the lower end of the cylinder, and a plurality of through bolts penetrating them. The end members at the lower ends of these through bolts are non-rotatably engaged with the chisel holder. In an impact tool in which a top nut is screwed into the upper end of a through bolt, a polygonal engaging portion and a male screw on the upper portion of the through bolt are integrally formed on the upper portion of each through bolt, and A separate lock seat plate having a polygonal engagement hole that immovably engages is provided, and the lock seat plate is locked with the engagement hole of the lock seat plate engaged with the engagement portion of the through bolt. The locking part provided on a part of the seat plate is non-rotatably locked to the receiving part of the handle cap, and the top nut is screwed into the male screw protruding above the lock seat plate. Even if you tighten it The bolt is obtained by the so as not to cause twist.

〔Example〕

In the embodiment shown in the drawings, 1 is a cylinder, 2 is a handle cap fixed to the upper end of the cylinder, 3 is a chisel holder fixed to the lower end, and a chisel 4 is mounted in the holder 3.

Reference numeral 5 denotes a plurality of through bolts inserted into a plurality of through holes provided in the cylinder 1, the cap 2 and the holder 3.

The lower end of the through bolt 5 is not rotatable with respect to the holder 3.

That is, the end member 7 at the lower end of the bolt 5 is fixedly screwed into the bolt 5 or fixed, or integrated with the bolt 5, and a part of the engaging portion of the end member 7 is engaged with the engaging portion of the holder 3. ,
Although the lower end of the bolt 5 cannot rotate with respect to the holder 3,
This point is the same as the known one.

A male screw 8 is provided at the upper end of the bolt 5 as shown in FIG. 3, and a lower portion thereof serves as an engaging portion 9.

In the case of the embodiment, the outer periphery of the engaging portion 9 is polygonal as shown in the lower left portion of FIG.

A lock seat plate 10 is made of a thick metal plate and has a polygonal engaging hole 11 with which the polygonal outer periphery of the engaging portion 9 engages.

In addition, an engaging portion 1 having an arc shape is formed on a part of the outer side of the seat plate 10.
2 is provided, and this locking part 12 is a part of the receiving part 1 of the cap 2.
It contacts 3 and cannot rotate.

Reference numeral 14 denotes a top nut, which is a cap nut in the illustrated example. The nut 14 is screwed into the male screw 8 as shown in FIG.

At this time, even if the nut 14 is strongly tightened, the lower surface of the nut 14 simply slides on the seat plate 10 and the bolt 5 is not twisted.

It should be noted that an appropriate loosening prevention may be provided between the nut 14 and the male screw 8.

[Effect of device]

As described above, according to this invention, a part of the lock seat plate in which a polygonal engaging hole is non-rotatably fitted in a polygonal engaging portion formed on the upper portion of the through bolt is received by the handle cap. The upper end portion of the through bolt cannot rotate because it is locked to the portion so as not to rotate.

Therefore, even if the top nut is screwed into the male screw of the through bolt protruding above the lock seat plate and the top bolt is tightly tightened, there is no possibility that the through bolt will be twisted, and an appropriate tensile force can be applied to the through bolt.

[Brief description of drawings]

FIG. 1 is a front view showing an example of an impact tool in which the device of the present invention is implemented, FIG. 2 is a plan view of the same as above, and FIG. 3 is an enlarged vertical front view of a main part. 5 ... through bolt, 8 ... male screw, 9 ... engaging portion, 10 ... lock seat plate, 12 ... locking portion, 13 ... receiving portion, 14 ... top nut.

Claims (1)

[Scope of utility model registration request] 1. A cylinder, a handle cap at the upper end of the cylinder, a chisel holder at the lower end of the cylinder, and a plurality of through bolts penetrating these cylinders. The end member at the lower end of each through bolt is rotated with respect to the chisel holder. In a shock tool that is immovably engaged and has a top nut screwed into the upper end of the same through bolt,
A polygonal engaging portion and a male screw on the upper portion thereof are integrally formed, and a separate lock seat plate having a polygonal engaging hole for non-rotatably engaging with the engaging portion is provided. With the engagement hole of the lock seat plate engaged with the engagement portion of the through bolt, the locking portion provided on a part of the lock seat plate is non-rotatably engaged with the receiving portion of the handle cap. Locking structure for impact tool with locking top nut screwed into the male screw protruding above the lock seat plate.