JPS5831655Y2 - Silencer for pneumatic impact tools - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a noise reduction device for a pneumatic impact tool using compressed air pressure as a driving source.

Conventionally, as an example of a pneumatic impact tool, a hitting piston is integrally connected with a driver, a hitting cylinder is slidably and tightly fitted with the hitting piston, a main air chamber is connected to an air pressure source, and the hitting piston is connected downwardly. and a return air chamber capable of applying return air pressure to the lower chamber side of the striking piston in the striking cylinder after reaching the dead center, so that return air pressure is applied to the lower chamber of the striking piston when the striking piston reciprocates within the striking cylinder. A pneumatic impact tool is known in which an exhaust passage for discharging a portion of air into the atmosphere is provided at the lower end of the impact cylinder.

The exhaust passage discharges the air that remains in the lower chamber of the striking piston and serves as a back pressure to the atmosphere during striking, that is, when the striking piston reciprocates, and allows the striking piston to move smoothly forward. At the time of return, a part of the return air introduced into the lower chamber of the striking piston is released into the atmosphere, so that a stable return state of the striking piston can be obtained.

By the way, when the striking piston strikes and returns, a part of the air acting in the lower chamber of the striking piston is suddenly released into the atmosphere from the exhaust passage, which generates unpleasant exhaust noise and becomes a source of noise. It had become.

Therefore, the present invention aims to eliminate the above-mentioned conventional drawbacks and provide a new noise muffling device that is highly effective at reducing exhaust noise without generating excessive exhaust resistance in the exhaust passage. This includes a striking piston to which the driver is integrally connected, a striking cylinder into which the striking piston is slidably and tightly fitted, a main air chamber led out to an air pressure source, and the above-mentioned after the striking piston reaches the bottom dead center. A return air chamber capable of applying return air pressure to the lower chamber side of the striking piston in the striking cylinder is provided, and when the striking piston reciprocates within the striking cylinder, a part of the air acting in the lower chamber of the striking piston is removed. In a pneumatic impact tool in which an exhaust passage for discharging into the atmosphere is provided on the lower end side of the impact cylinder, an air storage chamber is formed in the middle of the exhaust passage.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings, regarding an example in which the present invention is applied to a pneumatic nailing machine.

FIG. 1 is a diagram showing a first embodiment of the present invention, FIG. 1A is a vertical cross-sectional view of the vicinity of the lower end of the striking cylinder of the nailer, and FIG. 1B is an enlarged vertical cross-sectional view of the vicinity of the exhaust passage. It is a front view.

In FIG. 1A, numeral 2 denotes a nailer main body constituted by a housing portion of the nailer 1, in which a striking cylinder 3 is built and a nose 4 is disposed at the lower end.

That is, the diameter of the vicinity of the lower end 2a of the main body 2 is reduced, and the lower end 31 of the impact cylinder 3 is tightly fitted and held therein, and furthermore, at this lower end, there is a connecting portion provided at the base end of the nose 4 (upper end side in the figure). 41 are integrally connected.

As a result, the nose 4 has a driver guide hole 42 formed through the nose 4 in the axial direction and protrudes coaxially with the lower ends of the main body 2 and the impact cylinder 3.

The inner wall of the connecting part 41 of the nose 4 has a flat part 41b inside the annular inclined surface 41a on the outer peripheral side, and further has a stepped part 43 on the inside thereof into which the driver guide 5 is fitted and held.
is formed, and the portion 43 has a driver insertion hole 51 in the center.
A driver guide 5 having a diameter is loosely fitted therein.

A flange portion 52 is formed at the upper end of this driver guide 50 in the figure, and its surface 52a is a bun 1 which will be described later.
2, and a gap 8 is maintained between the flange portion local edge 52a' and the stepped portion peripheral wall 42a.

Further, 6 is a striking piston, and an O-ring 61,
They are tightly fitted through 61.

A driver 7 is integrally connected to this piston 6.

In addition, on the inner circumferential wall of the lower end portion 31 of the impact cylinder 3,
A large diameter portion 3c constituting a bumper holding portion is formed that has a larger diameter from step to step 3b than the cylinder main diameter portion 3a.

Further, 100 is a return air chamber that stores compressed air in the lower chamber 3B of the striking piston, which also flows into the return air passage 101 when the striking piston 6 moves forward, and the air in this return air chamber 100 is supplied to the striking piston. 6, the air flows into the striking piston lower chamber 3B again through the return air passage 101.

A bun 12 for stopping the striking piston 6 at the bottom dead center position within the striking cylinder 3 is incorporated in the lower end portion 31 of the striking cylinder.

The buns 12 are made of hard rubber material, etc.
A driver insertion hole 12a is provided in the axial direction of the central portion.

Further, an annular groove 12c is carved in the lower end surface, that is, the seating portion 12b of the driver guide 5 on the flange portion 52, and the annular groove 12c and the driver insertion hole 1
Radial recesses 12d and 12d are cut into the holes 2a and 2a, respectively.

On the other hand, the connecting portion 41 is provided with an exhaust passage 50 for discharging a part of the air acting in the lower chamber 3B of the striking piston of the striking cylinder 3 into the atmosphere.

This exhaust passage 50 is configured as described below.

That is, as shown in FIG. 1B, the connecting portion 41 is provided with an opening 51 that communicates with the inside of the lower chamber 3B of the impact cylinder, and the inner diameter of the opening 51 is gradually expanded from the inside to the outside. and a small diameter portion 51a, a medium diameter portion 51b, and a large diameter portion 51c.
It becomes.

The large diameter portion 51c includes an air flow rate adjustment bolt,
A so-called choke bolt 53 is screwed on.

That is, from one end (outside) of this choke bolt 53, an insertion hole 54 for a screwdriver having a hexagonal inner periphery is opened in the central axial direction.

Further, a large diameter hole 56 forming a part of an air storage chamber 57, which will be described later, is provided at the other end (inner side) of the choke bolt 53.

A small diameter hole 55 is formed through the center of the choke bolt 53σ to communicate the inside of the insertion hole 54 and the inside of the large diameter hole 56.

The inner diameter of the small diameter hole 55 is approximately the same as the inner diameter of the small diameter portion 51a.

Therefore, the exhaust passage 50 is constituted by the small diameter part 51a, the small diameter hole 55 of the choke bolt 53, and the insertion hole 54 for a screwdriver tool, and the medium diameter part 51
b and the large diameter hole 56 form an air storage chamber 51 provided in the middle of the exhaust passage 50.

That is, when the striking piston 6 moves forward and returns, the small diameter part of the opening 51 passes through the driver insertion hole 12a of the bumper 12, the radial recesses 12d, the -i-shaped groove 12c, and the gap 8. A part of the compressed air in the striking piston lower chamber 3B flowing into the blow piston 51a is temporarily stored in the air storage chamber 57.

Then, the air expands within the storage chamber 57, and the exhaust noise is absorbed.

The air is supplied to the small diameter hole 55 of the choke bolt 53,
It is released into the atmosphere through the screwdriver insertion hole 54.

That is, air with reduced exhaust noise is discharged into the atmosphere from the exhaust passage 50.

Next, a second embodiment of the present invention will be described with reference to FIG.

It should be noted that the same reference numerals are given to the parts having the same structure as those of the first embodiment.

As shown in FIG.
An opening 60 communicating with the inside of B is opened, and this opening 60
is gradually expanded in diameter from the inside to the outside, and has a small diameter portion 61a,
This is a large diameter portion 61b.

First, a first yoke bolt 71 is screwed onto the large diameter portion 61b, and then a second yoke bolt 81 is screwed onto the large diameter portion 61b.

The outer diameters of the first yoke bolt 71 and the second yoke bolt 81 are the same.

From one end (outside) of the first tie yoke bolt 71 is an insertion hole 72 for a screwdriver having a hexagonal inner circumference, and from the other end (inside) is a small diameter hole 73 having the same inner diameter as the small diameter portion 61a. are opened in the central axial direction, and the small diameter hole 73 and the insertion hole 72 communicate with each other.

On the other hand, from one end (outside) of the second tie yoke bolt 81, an insertion hole 82 for a screwdriver with a hexagonal inner periphery is opened in the central axial direction, and at the other end (inside), a large diameter hole 82 is opened.
3 have been established.

A small diameter hole 8 is provided in the center of the second jaw bolt 81 to communicate the inside of the insertion hole 82 and the inside of the large diameter hole 83.
4 is formed through the hole.

The inner diameter of this small diameter hole 84 is approximately the same as the inner diameter of the small diameter hole 73 of the first jaw bolt 71.

Therefore, the exhaust passage 90 includes the small diameter portion 61a, the small diameter hole 73 of the first choke bolt 71, the small diameter hole 84 of the second choke bolt 81, and the insertion hole 8 for a screwdriver tool.
2, and the insertion hole 72 for a screwdriver of the first jaw bolt 11 and the large diameter hole 83 of the second jaw bolt 810 form an air storage chamber 91 provided in the middle of the exhaust passage 90.

That is, as in the first embodiment, the air flowing into the small diameter portion 61a and the small diameter hole 73 of the first tie yoke bolt 71 through the gap 8 expands in the air storage chamber 91.
Exhaust noise is absorbed.

Then, the air is supplied to the small diameter hole 8 of the second choke bolt 81.
4 and an insertion hole 82 for a screwdriver into the atmosphere.

That is, air with reduced exhaust noise is discharged into the atmosphere from the exhaust passage 90.

As described above, according to the present invention, the air in the lower chamber of the striking piston, which is suddenly released into the atmosphere from the exhaust passage when the striking piston moves forward and returns, is temporarily stored in the exhaust passage, and is indirectly released into the atmosphere. Since the air can be discharged into the atmosphere, air with reduced exhaust noise can be discharged from the exhaust passage into the atmosphere.

Further, since no noise damping device such as an exhaust filter is disposed in the exhaust passage, no exhaust resistance is generated in the exhaust passage, and the sequence circuit of air acting within the impact tool body is not disrupted.

Furthermore, since there is no need to incorporate parts such as the exhaust filter, the configuration is simple.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the present invention, in which FIG. 1A is a vertical cross-sectional view of the vicinity of the lower end of the impact cylinder, and FIG. 1B is an enlarged vertical cross-sectional view of the vicinity of the exhaust passage. FIG. 2 is an enlarged longitudinal sectional view of the vicinity of the exhaust passage showing a second embodiment of the present invention. 1... Nailer, 3... Hit cylinder,
6...Blow piston, 7...Driver, 31...Blow cylinder lower end, 50, 90.
...Exhaust passage, 57, 91...Air storage chamber, 100...Return air chamber.

Claims (1)

[Scope of utility model registration request] A striking piston to which a driver is integrally connected, a striking cylinder in which the striking piston is slidably and tightly fitted, a main air chamber connected to an air pressure source, and a striking piston in the striking cylinder after the striking piston reaches the bottom dead center. A return air chamber capable of applying return air pressure to the piston lower chamber side is provided, and when the striking piston reciprocates within the striking cylinder, part of the air acting in the striking piston lower chamber is released into the atmosphere. 1. A sound muffling device for a pneumatic impact tool in which an exhaust passage is provided at the lower end of the impact cylinder, characterized in that an air storage chamber is formed in the middle of the exhaust passage.