JP3267469B2 - Buffer mechanism in pneumatic nailing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic nailing machine for driving a driver together with a striking piston by supplying and discharging compressed air to and from a striking cylinder. The driven striking piston is stopped at a bottom dead center. The present invention relates to a shock absorbing mechanism that absorbs the impact of a striking piston by using a special structure for a bumper for causing the shock.

[0002]

2. Description of the Related Art In general, a pneumatic nailer of this type drives a percussion piston using compressed air to drive out a nail. Recently, high-pressure compressed air has been used. Therefore, a high-power nailing machine can be realized despite its small size and good operability.

[0003] When the striking piston is driven by high-pressure air, the impact force increases, so that the shock-absorbing bumper for absorbing the impact of the striking piston must be enlarged. However, when the bumper is large, it is difficult to realize the miniaturization.

However, the bumper of the conventional nailing machine has a bending allowance formed on the outside, so that the bumper bends and deforms outward when subjected to the impact of the striking piston. Therefore, in order to absorb a larger impact force, it is necessary to form a large bending allowance in consideration of the amount of bending of the bumper to increase the amount of bending of the bumper. A problem occurs in that the durability of the bumper is reduced due to the large deflection of the bumper.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shock absorbing mechanism in a pneumatic nailing machine which can effectively absorb the impact of a striking piston driven by high-pressure air without increasing the size of a bumper. Its purpose is to

[0006]

Means for Achieving the Object To achieve the above object, a shock absorbing mechanism in a pneumatic nailing machine according to the present invention comprises:
A driver guide in which a driving piston integrally formed with a striking piston is formed at a lower portion of the striking cylinder by driving a striking piston in the striking cylinder by supplying and discharging compressed air from an upper end of a striking cylinder arranged inside the body. In a pneumatic nailing machine that penetrates through a hole and punches out an injection port, a cylindrical bumper that receives the lower surface of a striking piston is provided below the striking cylinder to cover the entire outer peripheral surface.
And the inner and outer diameters of the lower part of the bumper
Are larger than the inner diameter and the outer diameter of the upper part, respectively, so that a space larger than the upper part of the bumper is formed inside the lower part of the bumper, and the clearance between the driver and the driver guide hole is formed smaller.

[0007]

According to the present invention, the lower surface of the impact piston strikes the bumper after being driven by nail driving, so that the upper portion of the bumper is bent inward and deformed. At this time, the inner space of the bumper is compressed and reduced, and the opening at the upper end is closed by being pressed against the lower surface of the striking piston. Further, the clearance between the driver and the driver guide hole is formed small, and the air in the inner space cannot instantaneously escape from the clearance to the outside, so that the air trapped inside is compressed inside the bumper. Is done. The compressed air is discharged from the clearance immediately after the impact piston stops.

Thus, the impact of the striking piston is efficiently absorbed by the synergistic effect of the elasticity of the bumper and the air cushion generated inside the bumper. Therefore, the impact of the striking piston can be sufficiently absorbed without increasing the size of the bumper itself.

Further, since the air in the inner space cannot escape to the outside at a very short moment until the impact piston hits the bumper and stops, the bending deformation of the bumper is alleviated by the air sealed in the inner space. Since excessive deformation is prevented, the durability of the bumper is also improved.

[0010]

1 and 2 show a nailing machine according to the present invention. This nailing machine is provided with a compressed air supply source (inside of a body 1) like a normal pneumatic nailing machine. An air chamber 2 for storing compressed air introduced from a not shown) and a striking cylinder 3 are provided, and compressed air is supplied to and discharged from the striking cylinder 3 by operating a start valve 5 and a head valve 6 which are linked by operating a trigger lever 4. Then, the striking piston 7 in the striking cylinder 3 is reciprocated, and the driver 8 integrally connected to the striking piston 7 is driven into the nose 9 at the tip of the body 1, and the nail 10 supplied into the ejection opening of the nose 9 is disengaged. The driving is performed by hitting the material to be driven.

That is, as shown in FIG. 3, the trigger lever 4 pushes the valve stem 11 of the starting valve 5 to move the pilot valve 12 downward to open the air passage 13 to the exhaust port 14, so that the upper chamber of the head valve 6 can be opened. The compressed air 15 is discharged from the exhaust port 14, the head valve 6 is opened and the compressed air in the air chamber 2 is rapidly supplied into the striking cylinder 3 to drive the striking piston 7.

When the trigger lever 4 is returned after nailing, the valve stem 11 of the starting valve 5 is moved downward by a spring, and at the same time, the pilot valve 12 is moved upward, as shown in FIG. 13 to upper room 15
The compressed air supplied to the striking cylinder 3 is opened while the head valve 6 is closed and the exhaust valve 16 is opened, and the compressed air passes through the exhaust chamber 17 formed along the side surface of the body 1. It is exhausted outside. At the same time, the compressed air stored in the blowback chamber 18 around the striking cylinder 3 compressed at the time of striking causes the striking piston 7 to move upward, return to the initial top dead center position, and prepare for the next nail driving. It is.

By the way, a bumper 20 for receiving the lower surface of the driven impact piston 7 is disposed below the impact cylinder 3. The bumper 20 is formed in a cylindrical shape from an elastic material such as rubber, and has a lower inner diameter and
By making the outer diameter larger than the inner diameter and the outer diameter of the upper part , the bumper 20 is formed to bend inward when receiving an impact from above.

The driver 8 is inserted into a driver guide hole 21 provided below the bumper 20 and is slidably received in the exit of the nose portion 9. The clearance between the driver 8 and the driver guide hole 21 is so small that air in the inner space S of the bumper 20 does not easily escape from the clearance.

In the shock absorbing mechanism of the impact piston 7,
After the impact piston 7 is driven into the nail, the lower surface of the impact piston 7 is impacted against the bumper 20, so that the upper portion of the bumper 20 is bent inward as shown in FIG. At this time, bumper 2
The inside space S of 0 is compressed and reduced, and the opening at the upper end is pressed against the lower surface of the striking piston 7 and closed. Further, the clearance between the driver 8 and the driver guide hole 21 is formed small, and the air in the inner space S cannot instantaneously escape from the clearance to the outside. Compressed inside. The compressed air is discharged from the clearance immediately after the impact piston 7 stops.

As described above, the impact of the striking piston 7 is efficiently absorbed by the synergistic effect of the elasticity of the bumper 20 and the air cushion generated inside the bumper 20. Therefore, the impact of the striking piston 7 can be sufficiently absorbed without increasing the size of the bumper 20 itself.

Further, since the air in the inner space S cannot escape to the outside at a very short moment until the impact piston 7 hits the bumper 20 and stops, the bending deformation of the bumper 20 is also sealed in the inner space S. Since it is alleviated by air and excessive deformation is prevented, the durability of the bumper 20 is also improved.

[Brief description of the drawings]

FIG. 1 is a side view of a nailing machine according to the present invention.

FIG. 2 is a longitudinal sectional view of the nailing machine.

FIG. 3 is a sectional view of the nailing machine at the time of a nail driving operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 3 Impact cylinder 7 Impact piston 8 Driver 20 Bumper 21 Driver guide hole

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B25C 7/00 B25C 1/04

Claims (1)

(57) [Claims] 1. A striking piston in a striking cylinder is driven by nailing by supplying and discharging compressed air from an upper end of a striking cylinder disposed in a body, and a driver integrally coupled with the striking piston is driven by a lower portion of the striking cylinder. In the pneumatic nailing machine, which penetrates through a driver guide hole formed in the above and punches into an injection port, a cylindrical bumper for receiving a lower surface of a striking piston is accommodated below the striking cylinder.
And arranged to, in the lower portion of the bumper inner and outer diameter upper portion of the
A pneumatic nailing machine characterized in that a space larger than the upper part of the bumper is formed inside the lower part of the bumper by making it larger than the inner diameter and the outer diameter , and the clearance between the driver and the driver guide hole is made smaller. Buffer mechanism.