JPH01274971A - Striking tool - Google Patents

Abstract

PURPOSE:To prevent dust from being deposited between both air chambers to prevents a reduction in a striking force adjusting function of a striking tool by providing a volume varying means for varying the volume of a second air chamber while a relative position between a striking member, a piston member and the second air chamber formed in the striking tool body so as to be connected to a first air chamber is maintained. CONSTITUTION:A striking force is adjusted by adjusting the volume of a second air chamber 8 by means of a volume varying means (adjusting bolt) 9, adjusting the sum of the volume of a first air chamber formed between a striker 3 and a piston member 6 and the volume of the second air chamber 8, and adjusting the amount of advance and retract of the striker 3 with respect to a preset amount of advance and retract of the piston member 6. In this instance, since the second air chamber 8 is connected to the atmosphere only through the first air chamber 5 without being directly connected to the surrounding atmosphere, dust floating in the surrounding atmosphere does not penetrate into between both air chambers 5, 8, thereby being not deposited. A passage between the first and second air chambers 5, 8 is, as a result, no blocked by dust, and a reduction in the cross-sectional area of the passage can be prevented for many hours.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an impact tool, and particularly to an impact tool that is less likely to deteriorate or lose its impact force adjustment function.

[Prior Art] Conventionally, as an impact tool, as shown in FIG. 5, for example,
A chisel 2 is slidably inserted into the front end of the impact tool body 1, and a striking member 3 is slidably attached to the impact tool body 1 behind the chisel 2 and strikes the chisel 2.
By expanding or compressing an air chamber 5 formed between the striking member 3 and the striking member 3, the air chamber 5 is slidably attached to the striking tool main body 1 behind the striking member 3 and is slid back and forth by the driving means 4. There is a piston member 6 for moving the striking member 3 back and forth, and the air chamber 5 is communicated with the atmosphere via a variable throttle valve 7 (Utility Model No. 56-7267
(See Publication No. 7).

In this conventional example, by adjusting the opening/closing degree of the variable throttle valve 7, the internal pressure of the air chamber 5 can be adjusted and the impact force can be arbitrarily changed.

[Problems to be Solved by the Invention] However, according to the above-mentioned conventional example, since the air chamber 5 and the atmosphere are communicated via the variable throttle valve 7, dust floating in the surrounding atmosphere is removed from the atmosphere. At the same time, the air enters and exits the air chamber 5, clogging the variable throttle valve 7, resulting in a reduction or loss of the impact force adjustment function.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a striking tool in which the impact force adjustment function is less likely to be degraded or lost.

[Means for Solving the Problems] A striking tool according to the present invention includes a chisel slidably inserted into the front end of a striking tool body, and a chisel slidably attached to the striking tool body behind the chisel. A first air chamber formed between a striking member that strikes the chisel and the striking member, which is slidably attached to the striking tool body behind the striking member and is slid back and forth by a driving means. The impact tool has a piston member that moves the impact member back and forth by expansion or compression, and the impact tool body includes the first
The device includes a second air chamber formed in communication with the air chamber, and a volume variable means for varying the volume of the second air chamber while maintaining the relative position of the striking member and the piston member. .

[Operation] In the impact tool according to the present invention, the total volume of the first air chamber and the second air chamber can be adjusted by adjusting the volume of the second air chamber using the volume variable means, so that the total volume of the first air chamber and the second air chamber can be set constant. The striking force is adjusted by adjusting the amount of movement of the striking member relative to the amount of movement of the piston member back and forth. Also, the second
Since the air chamber is not directly communicated with the surrounding atmosphere but only communicated with the atmosphere through the first air chamber, dust floating in the surrounding air is transferred between the first air chamber and the second air chamber. There is no possibility that dust will accumulate between the first air chamber and the second air chamber, and the darkness between the first and second air chambers will not be blocked by dust or the passage between them will be interrupted. It is possible to prevent the area from decreasing over a long period of time.

[Effects of the Invention] According to the impact tool according to the present invention, as explained above, by adjusting the volume of the second air chamber by the volume variable means, the total of the first air chamber and the second air chamber can be adjusted. The impact force can be adjusted by adjusting the volume and adjusting the amount of movement of the striking member relative to the amount of movement of the piston member back and forth which is set constant. Moreover, dust in the atmosphere does not accumulate between the first air chamber and the second air chamber, and the space between the first and second air chambers is not blocked by dust or the cross-sectional area of the passage is reduced. It is possible to prevent the impact force adjustment function from deteriorating or being lost due to the accumulation of dust for a long period of time.

[Example 1 Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, in this embodiment, the present invention is applied to a striking tool in which a chisel 2 moves forward and backward but does not rotate. A chisel 2 is slidably inserted into the front end (left end in the figure) of the tool body 1, and a chisel 2 is slidably attached to the impact tool body 1 behind the chisel 2 and strikes the chisel 2. A first air chamber is formed between a striker 3 as a striking member and the striker 3, which is slidably attached to the striking tool main body 1 behind the striker 3 and slid back and forth by a driving means 4. The piston member 6 moves the striking member 3 back and forth by expansion or compression of the piston member 5. The impact tool main body 1 includes a second air chamber 8 formed in communication with the first air chamber 5, a back pressure chamber 7 formed in front of the piston portion 3a of the striker 3, and a second air chamber 8 formed in communication with the first air chamber 5; An adjustment bolt 9 is provided as a volume varying means for varying the volume of the second air chamber 8 while maintaining the relative position with the piston member 6.

The impact tool main body 1 includes a housing 10 and a cylinder 11 into which the striker 3 and the piston member 6 are fitted. ing.

In order to form the second air chamber 8, the first air chamber 5 is formed when the piston member 6 is at the forward limit position shown in FIG.
A cylindrical chamber forming part 10a is formed in a protruding manner at one location on the outer periphery of the housing 10 at a position corresponding to the rear part of the housing 10. An adjustment bolt 9 is screwed into the chamber forming part 10a from the outside through a screw in an airtight manner, and the chamber forming part 10a and the female screw 9 are screwed together from the outside.
A second air chamber 8 is formed.

Further, the cylinder 11 is formed with a small-diameter communication hole 16 as shown in FIG. When the striker 3 is at the forward limit position, the back pressure chamber 7 is connected to the atmosphere communication passage 17 through the communication hole 16, and when the striker 3 is at the forward limit position, the first air chamber 5 is connected to the atmosphere through the communication hole 16. .

The drive means 4 is not particularly limited as long as it is configured to drive the piston member 6 back and forth, and may include, for example, a drive source (not shown) such as an electric, pneumatic, or hydraulic motor, or an engine, and the drive source. A rotating plate 12 that is rotated;
An eccentric pin 13 is provided on the rotary plate 12, and one end is pivotally connected to the eccentric pin 13 and the other end is connected to the piston member 6.
and a connecting rod 15 pivotally connected via a piston pin 14, so that the piston member 6 can be reciprocated in the front-rear direction with a predetermined stroke.

The piston member 6 is moved into the cylinder 14 by the driving means 4.
It reciprocates back and forth at the rear of the chisel 2, compresses the air in the first air chamber 5 and the second air chamber 8 as it moves forward, and causes the striker 3 to collide with the chisel 2 with an impact due to the air pressure.
It is designed to give striking power to.

To explain the impact operation of the above-mentioned impact tool, immediately after striking the chisel 2 with the striker 3, communication is made by the striker 3, which initially retreats due to the air pressure in the back pressure chamber 7 and the repulsive force accompanying the collision with the chisel 2. The hole 16 is closed, and as the piston member 6 moves backward at high speed during this time, the first air chamber 5 and the second air chamber 8 become negative pressure, and this negative pressure causes the striker 3 to move to one point. Move to the retraction limit position shown by the chain line.

During this time, the piston member 6 passes through the retraction limit position shown by the two-dot chain line and moves forward, and the internal pressure in the first air chamber 5 and the second air chamber 8 rises rapidly, and when the striker 3 reaches the retraction limit position. When the internal pressure reaches its peak, the striker 3 rapidly moves forward due to the internal pressure and collides with the rear end of the chisel 2 to strike it.

At that moment, the first air chamber 5 communicates with the atmosphere through the communication hole 16, but at the next moment, the back pressure chamber 7 communicates with the atmosphere through the communication hole 16, facilitating the backward movement of the striker 3. It is supposed to be done.

The amount of retraction of the striker 3 is determined depending on the degree of pressure reduction in the first air chamber 5, but since the amount of retraction of the piston member 6 is constant, the amount of retraction of the striker 3 is determined depending on the degree of pressure reduction in the first air chamber 5. It will be determined depending on the total volume of the communicating second air chambers 8.

Here, to explain the structure for communicating the first air chamber 5 and the second air chamber 8, a protrusion 18 is formed on the outer peripheral surface of the cylinder 11 that constitutes the peripheral wall of the first air chamber 5, and this A vent hole 19 passing through the protrusion 1 and the peripheral wall of the cylinder 11 is formed, and the second air chamber 8 is opened on the inner peripheral surface of the housing 10 at the position of the vent hole 19.
A sealing member 21 is installed between the housing 8 and the inner peripheral surface of the housing 10.

The adjustment bolt 9 is screwed onto the side opposite to the opening 20 of the second air chamber 8, and by screwing it forward and backward, the second air chamber 8
It is designed to adjust the volume of. Then, during the adjustment, the total volume of the first air chamber 5 and the second air chamber 8 is transferred to the first air through the volume compensation passage 22 in a volume corresponding to the volume of the second air chamber 8 that has been increased or decreased due to the adjustment. By introducing the air into the chamber 5 and the second air chamber 8, the striker 3 is prevented from being displaced during volume adjustment. In addition, the adjustment bolt 9
A lock nut 23 for fixing this to the housing 10 is screwed onto the housing 10 at an arbitrary position, and by tightening this nut 22 toward the housing 10, this and the housing 1 are screwed together.
0 ring 24 interposed between the 0 ring 24 and the 0 ring 24
2 can be closed off.

In this configuration, when the volume of the second air chamber 8 is adjusted by screwing the adjustment bolt 9 back and forth, the total volume of the first air chamber 5 and the second air chamber 8 is increased or decreased. When the volume of air chamber 8 is increased, the total volume of first air chamber 5 and second air chamber 8 increases, and the negative pressure within first and second air chambers 5 and 8 when piston member 6 retreats is alleviated. Striker 3
Since the backward movement of the piston member 6 is reduced and the air pressure in the first and second air chambers 5 and 8 is relaxed when the piston member 6 moves forward, the striking force applied to the chisel 2 is reduced. On the other hand, when the volume of the second air chamber 8 is reduced, the impact force increases.

Further, the second air chamber 8 is not directly opened to the atmosphere, but is communicated with the atmosphere via the first air chamber 5, the communication hole 16, and the atmosphere communication path 17, and when in use, the second air chamber 8 is Since the volume is fixed, the amount of air flowing in and out of the second air chamber 8 is much smaller than the amount of air flowing in and out of the first air chamber 5 from the atmosphere communication passage 17. Therefore, dust floating in the atmosphere Almost no dust enters the ventilation hole 19 or the opening 20, and even if it does, since the ventilation hole 19 and the opening 20 are formed relatively large, they will not be clogged with dust.

As a result, the impact force adjustment function can be maintained for a long period of time.

In the above embodiment, the volume compensation passage 22 is formed in the portion of the housing 10 surrounding the second adjustment chamber 8. For example, as shown in FIG. A passage 22A is formed, and a passage 2 for volume compensation is formed.
A machine screw 25 screwed into the adjustment bolt 9 at the outer end of 2A
It is also possible to configure it so that it can be opened and closed using an O-ring 26.

Furthermore, the present invention can be applied to a striking tool configured such that the chisel 2 rotates as it advances and retreats. In this case, for example, as shown in FIG. 4, the first air chamber 5
A bearing 27 for rotatably fitting the cylinder 1j into the housing 10 is provided around the outer periphery of the housing 10.
Circumferential grooves 28 and 29 that communicate with each other on the inner circumferential surface and outer circumferential surface of
The inner circumferential groove 28 and the ventilation hole 19A penetrating the circumferential wall of the cylinder 11 communicate with each other, and the outer circumferential groove 29
By communicating with the opening 20 of the second air chamber 8,
The first air chamber 5 and the second air chamber 8 can be communicated with each other at all times.

[Brief explanation of the drawing]

FIG. 1 is a cutaway longitudinal sectional side view of the main part of the impact tool according to the embodiment of the present invention, FIG. 2 is an enlarged longitudinal sectional view of the second air chamber and adjustment bolt, and FIG. FIG. 4 is a view corresponding to FIG. 2 showing a modification, FIG. 4 is a view corresponding to FIG. 2 of an impact tool according to another embodiment, and FIG. 5 is a longitudinal sectional view of a main part of a conventional example. 1. Impact tool body, 2. Chisel, 3. 4 strikers, 4. Drive means, 5. First air chamber, 6
...Piston member, 8.Second air chamber, 9.Adjustment bolt. Figure 2

Claims (1)

[Claims] (1) A chisel that is slidably inserted into the front end of the impact tool body, a striking member that is slidably attached to the impact tool body behind the chisel and that strikes the chisel, and the rear of the striking member. a piston member which is slidably attached to the impact tool body and is slid back and forth by a driving means to move the impact member back and forth by expansion or compression of a first air chamber formed between the impact tool body and the impact tool body; In the impact tool, the impact tool has a second air chamber formed in the impact tool main body in communication with the first air chamber, and a relative position between the impact member and the piston member is maintained so that the second air chamber is in communication with the first air chamber. A striking tool characterized by comprising a volume variable means for varying the volume.