JPH0753902Y2 - Head valve of nailer - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head valve which is not affected by the phenomenon of freezing due to adiabatic expansion during driving in a nailing machine driven by compressed air.

[0002]

2. Description of the Related Art Generally, in a nailing machine driven by compressed air, as shown in FIG. 4, a head valve 21 is arranged at an upper end portion of a striking cylinder 20, and an opening / closing operation of the head valve 21 causes an inside of the striking cylinder 20 to move. Is selectively connected to the air chamber 22 of the compressed air and the exhaust port 25 to drive the striking piston 23 in the striking cylinder 20. A compression spring 24 for urging the head valve 21 to the closed position is arranged in the nailing machine, and compressed air introduced into the striking cylinder 20 from the air chamber 22 and driving the striking piston 23 is compressed by the striking cylinder 20. When discharged from the inside to the exhaust port 25, the structure is such that it is discharged via the compression spring 24. The compression spring 24 is formed in a coil shape,
The compressed air passes from the inside to the outside of the compression spring 24,
At this time, it will pass between the springs. However, the compressed air expands rapidly when discharged from such a narrow exhaust space, so the adiabatic expansion cools the peripheral portion,
Ice droplets 26 adhere to the periphery of the compression spring 24 and the head valve 21. The ice droplets of the compression spring 24 further narrow the narrow exhaust space, which deteriorates the exhaust performance. When the exhaust performance deteriorates, the compressed air is not exhausted sufficiently, so that the striking piston 21 returns to the top dead center poorly.
The operation of the nailing machine becomes unstable and problems such as idle driving and defective driving occur.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks and to provide a head valve which can be operated satisfactorily without being affected by the phenomenon of freezing due to adiabatic expansion during driving.

[0004]

To achieve the above object, a head valve of a nailing machine according to the present invention comprises a striking cylinder for slidably accommodating a striking piston for striking a nail and an upper portion of the striking cylinder. In a nailing machine in which a head valve is arranged and compressed air is supplied to and exhausted from the striking cylinder by opening and closing the head valve to drive the striking piston in a nailing direction, the head valve has a substantially cylindrical shape. Of the head valve body and a flange formed in the inner diameter direction from the lower end of the head valve,
The flange is disposed below a cylinder cap disposed above the striking cylinder, and a compression spring that urges the head valve downward is disposed between the inner end of the flange and the cylinder cap. In addition, a plurality of exhaust openings are dispersedly arranged on the flange.

[0005]

According to the above construction, when the striking piston moves upward and the compressed air supplied into the striking cylinder is discharged, a part of the compressed air passes from the inside to the outside of the compression spring. Adiabatic expansion of the compressed air cools the peripheral portion of the compression spring, and ice droplets adhere to the periphery of the compression spring and the head valve. However, most of the compressed air passes through the exhaust opening of the flange of the head valve, so that exhaust failure does not occur. As described above, since the exhaust performance is not deteriorated by the phenomenon of freezing, the striking piston can be surely moved to the top dead center, and it is possible to effectively prevent occurrence of phenomena such as idling and defective driving.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of a nailing machine, which is shown in a nailing machine main body 1 in FIGS. The striking cylinder 2 is vertically arranged, the striking piston 3 is slidably accommodated in the striking cylinder 2, and a nose portion 4 is extended below the striking cylinder 2 and the striking piston 4 is provided in the nose portion 4. The driver 3a integrally connected to the impact cylinder 3 is guided, and the compressed air is supplied and exhausted above the impact cylinder 2 by the opening / closing operation of the head valve 5 provided above the impact cylinder 2, whereby the impact piston 3 Is driven to strike the nail in the nose portion 4 to drive it out.

A cylinder cap 6 is provided above the striking cylinder 2, and an annular valve housing 7 is formed so as to open downward around the outer circumference of the cylinder cap 6.

The head valve 5 is composed of a substantially cylindrical head valve body 5a and a flange 5b formed in the inner diameter direction from the lower end of the head valve 5, and a plurality of exhaust openings 8 are dispersed in the flange 5b. It is arranged. The outer peripheral portion 9 of the lower surface of the flange 5b is made of urethane resin and faces the upper end surface 10 of the striking cylinder 2 so as to come into contact therewith to form a sealing surface. The lower surface of the outer peripheral portion of the head valve 5 is exposed to the air chamber 11 in which compressed air is stored, and an air passage 12 leading to a trigger valve (not shown) is formed at the upper end of the valve housing 7.

The head valve body 5a of the head valve 5 is slidably accommodated in the valve housing 7. The flange 5b is arranged under the cylinder cap 6 arranged on the upper part of the striking cylinder 2, and the head valve 5 is arranged downward between the inner end of the flange 5b and the cylinder cap 6 of the striking cylinder 2. A compression spring 13 is arranged to urge it toward. 14 is a spring receiving member. The head valve 5 is normally held in the position (closed position) shown in FIG. 2 by the pressure of the compressed air sent from the air passage 12 into the valve housing 7 and the spring pressure of the compression spring 13.

Further, between the outer peripheral surface of the cylinder cap 6 and the inner peripheral surface of the head valve body 5a, the striking cylinder 2 is provided.
An exhaust passage a is formed for exhausting the compressed air therein to the exhaust port 15 above the nailer.

In the above-mentioned structure, when the compressed air in the valve housing 7 is exhausted from the air passage 12 by activating the trigger valve, the air chamber 1
Since the air pressure in 1 acts on the lower surface of the outer peripheral portion of the head valve 5 and pushes the head valve 5 upward as shown by an arrow P against the pressure of the compression spring 13 of the compression spring 13, the head valve 5 is a striking cylinder. Move away from the top edge of 2 to the open position. Therefore, the compressed air in the air chamber 11 is rapidly introduced into the striking cylinder 2, and the striking piston 3 is pushed down to drive the nail in the nose portion 4 to strike it.

On the other hand, when the trigger valve is operated to supply compressed air from the air passage 12 into the valve housing 7, the head valve 5 is closed again by the air pressure and the spring pressure of the compression spring 13 as shown in FIG. To position
The supply of compressed air from the air chamber 11 is stopped. At the same time, the striking piston 3 is moved upward by another mechanism, and the compressed air supplied into the striking cylinder 2 is discharged from the exhaust passage a. At this time, a part of the compressed air passes from the inside to the outside of the compression spring 13, so that the peripheral portion of the compression spring 13 is cooled by the adiabatic expansion of the compressed air, and ice droplets cause the compression spring 13 and the head valve 5 to cool. Adhere to around. However, since most of the compressed air passes through the exhaust opening 8 of the flange 5b of the head valve 5, exhaust failure does not occur. As described above, since the operation of the nail driving machine is not affected by the phenomenon of freezing, the striking piston 3 can surely move to the top dead center, and it is possible to effectively prevent the occurrence of phenomena such as idle driving and defective driving. can do.

The phenomenon of freezing occurs even when compressed air is introduced into the striking cylinder 2 from the air chamber 11, but since urethane is used for the sealing surface of the head valve 5, ice is used for the sealing surface. Drops are less likely to attach, preventing poor sealing.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view of a head valve of the nail driver.

FIG. 3 is an explanatory diagram of an exhaust state of compressed air.

FIG. 4 is a cross-sectional view of a main part around a conventional head valve.

[Explanation of symbols]

 2 striking cylinder 3 striking piston 5 head valve 5a head valve body 5b flange 6 cylinder cap 8 exhaust opening 13 compression spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Yoshizawa, 6-6, Hakozakicho, Nihonbashi, Chuo-ku, Tokyo, Max Co., Ltd. (56) References: 61-191876 (JP, U): 55 -147273 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A striking cylinder for slidably accommodating a striking piston for striking a nail, and a head valve arranged above the striking cylinder, and opening and closing the head valve to supply compressed air to the striking cylinder. In a nailing machine that drives the striking piston in the nailing direction by exhausting, the head valve is formed from a substantially cylindrical head valve main body and a flange formed in an inner diameter direction from a lower end portion of the head valve. A compression spring for arranging the flange at a lower portion of a cylinder cap arranged at an upper portion of the striking cylinder and for urging the head valve downward between an inner peripheral side end portion of the flange and a cylinder cap. A head valve for a nailing machine, characterized in that a plurality of exhaust openings are dispersedly arranged on the flange.