JPH09201778A - Air nailing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the noise of an air nailing machine by decreasing the exhaust sound of the machine. SOLUTION: A blow back chamber 29 is formed in the periphery of an air cylinder 27 and an exhaust chamber 30 is also formed outside of the blow back chamber 29 by inserting a cylinder diaphragm 26 and a ring-shaped diaphragm 28 into a cylinder housing part 23. An exhaust port 34 of the exhaust chamber 30 is provided radially in the cylinder housing part 23. An exhaust port 37 of a switching valve 35 and the exhaust chamber 30 are connected with an exhaust pipe 38. In the return stroke of a piston 46, the pressurized air in an air cell 42 of the air cylinder 27 is exhausted from the exhaust port 34 outside through the exhaust port 37, the exhaust pipe 38, and the exhaust chamber 30. At this time, the heat of a bumper 49 is absorbed through the cylinder housing part 23 by expansion of the pressurized air and is cooled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air nailer, and more particularly to an air nailer having an improved exhaust mechanism.

[0002]

2. Description of the Related Art A conventional pneumatic nailing machine will be described with reference to FIG. As shown in the figure, in the air nailing machine 1, an air cylinder 3 is built in a cylinder housing portion 2, and a blowback chamber 4 is formed around the air cylinder 3. The air cylinder 3 is controlled by a hollow switching valve 6 that opens and closes a rear air chamber of the rear surface of the piston 5, and the switching valve 6 is pilot-operated by a trigger valve 7.

The rear small diameter portion of the switching valve 6 is inserted into a guide hole provided in the cylinder housing portion 2 and protrudes rearward,
An exhaust chamber 8 for accommodating a protruding portion of the switching valve 6 is formed in the cylinder housing portion 2, and one side surface of the exhaust chamber 8 is opened to the atmosphere to form an exhaust port.

In the standby state, the switching valve 6 is advanced by the pressure air supplied from the trigger valve 7 to the air chamber 10 of the switching valve 6 through the pilot line 9, and the rear air chamber 11 and the pressure air chamber 12 of the air cylinder 3 are advanced. And cut off.

When the trigger valve 7 is operated and the pressure air in the air chamber 10 of the switching valve 6 is discharged, the switching valve 6 is retracted by the pressure air acting on the outer peripheral surface of the front portion, and the pressure air chamber 12 and While communicating with the rear air chamber 11 of the air cylinder 3, the switching valve 6 is brought into pressure contact with the baffle plate 8 to close the center hole, and the rear air chamber 11 of the air cylinder 3 and the atmosphere are shut off.

When the contact arm 14 mounted on the nose block 13 is pressed against the surface to be nailed and pushed in and the trigger lever 15 is pulled, the trigger valve 7 is opened, and the pressure in the rear air chamber 11 of the air cylinder 3 and the pressure are increased. The piston 5 is activated by communicating with the air chamber 12.

When the piston 5 advances from the standby position and the driver rod 16 injects the nail N in the nose block 13, the pressurized air is vented to the outer peripheral surface of the air cylinder 3, the vents 17 and 18 and the flap valve. It flows into the blowback chamber 4 in the outer peripheral portion through 19 and the piston 5 collides with the rubber bumper 20 in the front portion of the air cylinder 3.

When the trigger lever 15 or the contact arm 14 is turned off, the switching valve 6 returns to the standby position, the rear air chamber 11 of the air cylinder 3 communicates with the atmosphere, and the piston 5 moves to the blowback chamber 4. It retreats due to pressure. At this time, the compressed air in the rear air chamber 11 of the air cylinder 3 is discharged rearward through the center hole of the switching valve 6, and is discharged to the surroundings from the gap between the baffle plate 8 and the cylinder housing portion 2.

[0009]

In the conventional air nailing machine, since the exhaust port is provided close to the air chamber of the air cylinder in the cylinder housing portion, the exhaust path from the air cylinder is short and the exhaust noise is low. However, there is a demand for low noise.

Further, although the bumper is hit by a piston to generate heat, there is a problem that during continuous work for a long time, the temperature rises and the deterioration of the bumper is accelerated, resulting in deterioration of durability. Therefore, there is a technical problem to be solved in order to improve the working environment by reducing the exhaust noise of the air nailing machine, and prevent the deterioration of durability. The present invention solves the above problems. The purpose is to

[0011]

DISCLOSURE OF THE INVENTION The present invention is proposed in order to achieve the above-mentioned object, and accommodates an air cylinder in the cylinder housing portion of the nailer housing,
A blowback chamber is formed by closing a cylindrical space between the outer peripheral surface of the air cylinder and the inner wall surface of the cylinder housing portion, and the front portion of the air cylinder and the blowback chamber are communicated with each other, and A switching valve for selectively switching the rear air chamber to the exhaust port or the pressure air chamber in the housing is provided, and the switching valve is operated to drive the piston of the air cylinder to be supplied into the nose block of the housing. In the pneumatic nailing machine, a nail is ejected by a driver rod connected to the piston, and the piston is retracted by the compressed air accumulated in the blowback chamber in the forward stroke of the piston to return to the standby position. The cylindrical space between the outer peripheral surface of the cylinder and the inner wall surface of the cylinder housing is At the coaxial double cylindrical space is divided and closed, the inner space is communicated with the front part of the air cylinder as a blowback chamber, and the outer space is connected to the exhaust port of the switching valve, The present invention provides an air nailing machine characterized in that an exhaust chamber is provided by providing an exhaust port communicating the outside space with the atmosphere.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to FIGS. The figure shows an air nailer 2
1 shows a die-cast housing 22 in which a cylinder housing portion 23 and a hollow grip portion 24 are integrally formed, and an end cap 2 is provided at an opening end portion of the grip portion 24.
5 is screwed in. A mounting hole for an air connector plug (not shown) is opened at the center of the end cap 25,
The air connector plug and the air compressor are connected by a hose to supply pressurized air from the air compressor into the grip portion 24.

In the cylinder housing portion 23, a cylindrical partition wall 26 having a diameter smaller than the inner diameter of the cylinder housing portion 23.
An air cylinder 27 having a diameter smaller than that of the cylindrical partition wall 26 is coaxially arranged. Inside the cylinder housing portion 23, the inner wall surface of the cylinder housing portion 23 and the air cylinder 2
A ring-shaped partition wall 28 that is in contact with the outer peripheral surface of 7 is inserted into contact with the rear end portion of the cylindrical partition wall 26, and the cylindrical space between the air cylinder 27 and the cylinder housing portion 23 is the cylindrical partition wall 26 and the ring-shaped partition wall. 28 is divided into a blowback chamber 29 outside the air cylinder 27 and an exhaust chamber 30 outside the blowback chamber 29.

Vent holes 31 and 32 are opened in the front side surface of the air cylinder 27 and slightly rearward thereof, and a flap valve 33 is attached to the outside of the rear vent hole 31.
In addition, an exhaust port 34 that connects the exhaust chamber 30 and the atmosphere is also radially provided in the front portion of the cylinder housing portion 23.

The switching valve 35 arranged at the rear portion of the air cylinder 27 is a spool valve having a through hole at its center, and has a small diameter portion protruding rearward from the center of the large diameter portion at the front portion.

A cylinder cap 36 is mounted on the rear end of the cylinder housing portion 23.
The small diameter portion of the switching valve 35 is inserted into a guide hole provided in the inner partition wall, and the exhaust port 37 opened and closed by the switching valve 35.
Are formed. Exhaust port 37 and exhaust chamber 30
And are connected by an exhaust pipe line 38 indicated by a chain line. A switching valve 35 is provided on the inner wall surface of the rear portion of the cylinder cap 36.
Is installed, and when the switching valve 35 is retracted, the valve seat 36a is pressed against the valve seat 36a to close the space between the rear air chamber of the air cylinder 27 and the exhaust port 37.

The air chamber 39 formed by the rear surface of the large diameter portion of the switching valve 35 and the rear wall of the cylinder housing portion 23 is connected to the trigger valve 41 of the grip portion 24 by the pilot conduit 40, and The pipe 40 and the exhaust pipe 38 intersect with each other in the drawing, but they are independent pipes.

The operation of the trigger valve 41 and the switching valve 35 and the operation of the air cylinder 27 are the same as those of the conventional pneumatic nailing machine, and in the standby state shown in the figure, the air chamber of the switching valve 35 is passed through the trigger valve 41. By the pressurized air supplied to 39,
The switching valve 35 is advanced to a position that shuts off the rear air chamber 42 of the air cylinder 27 and the pressure air chamber 43 in the grip portion 24.

When the trigger lever 44 and the contact arm 45 are operated, the pressure air in the air chamber 39 of the switching valve 35 is discharged through the trigger valve 41, and the pressure air chamber 43 acting on the outer peripheral surface of the front portion of the switching valve 35. The switching valve 35 retracts due to the pressure. As a result, the pressure air chamber 43 and the rear air chamber 42 of the air cylinder 27 communicate with each other, and the switching valve 35 serves as the valve seat 36 of the cylinder cap 36.
The rear air chamber of the air cylinder 27 and the exhaust port 37 are closed by being pressed against a, and the piston 46 of the air cylinder 27 is activated by the pressure of the pressure air chamber 43.

The driver rod 47 connected to the piston 46 advances along the guide hole of the nose block 48 attached to the tip of the cylinder housing portion 23 and ejects the nail N supplied into the nose block 48. When the piston 46 advances, the air on the front surface of the piston 46 is compressed and filled in the blowback chamber 29 through the vent holes 31 and 32, and the piston 46 collides with the bumper 49 on the front part of the air cylinder 27.

When the trigger lever 44 or the contact arm 45 is turned off and the trigger valve 41 returns to the initial position, the pressurized air is supplied to the air chamber 39 of the switching valve 35, the switching valve 35 moves forward, and the air cylinder 27 Rear air chamber 42
Is shut off from the pressure air chamber 43 and the exhaust port 37
Communicate with As a result, the compressed air accumulated in the blowback chamber 29 is transferred to the piston 46 through the vent 32.
And the compressed air in the rear air chamber 42 of the air cylinder 27 is discharged to the outside from the exhaust port 34 via the exhaust port 37, the exhaust pipe line 38, and the exhaust chamber 30.

As described above, since the large-capacity exhaust chamber 30 is provided in the path from the rear air chamber 42 of the air cylinder 27 to the atmosphere, the burst sound accompanying the expansion of the pressurized air is attenuated in the exhaust chamber 30, The exhaust sound volume is significantly reduced.

Also, in the exhaust stroke, the air cylinder 27
The compressed air therein is cooled by expanding in the exhaust chamber 30, and this cooled air is cooled by the cylinder housing portion 23.
To cool the walls. Therefore, the heat of the rubber bumper 49, which is hit by the piston 46 to generate heat, is absorbed through the cylinder housing portion 23 to cool the bumper 49, and the deterioration of the bumper 49 due to the heat is prevented.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the technical scope of the present invention, and it is a matter of course that the present invention extends to those modifications. is there.

[0025]

As described above, in the pneumatic nailing machine of the present invention, the exhaust chamber is formed inside the cylinder housing, and the compressed air of the air cylinder is discharged from the exhaust chamber to the outside of the cylinder housing. Due to the sound deadening effect of the large-capacity exhaust chamber, the exhaust sound is significantly reduced as compared with the conventional air nailer.

Further, when the compressed air is discharged from the exhaust port provided in the front portion of the cylinder housing portion, the housing is cooled by the air expansion and the heat of the rubber bumper in the air cylinder is absorbed, so that the elasticity of the bumper is increased. It exerts various effects such as suppressing deterioration and improving durability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an air nailing machine showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a cross-sectional view of a pneumatic nailing machine showing a conventional example.

[Explanation of symbols]

 21 Air nailing machine 22 Housing 23 Cylinder housing part 24 Grip part 26 Cylindrical partition wall 27 Air cylinder 29 Blow back chamber 30 Exhaust chamber 34 Exhaust port 35 Switching valve 36 Head cap 38 Exhaust pipe line 43 Pressure air chamber 49 Bumper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Makoto Kosuge 6-6 Nihonbashi-Hakozakicho, Chuo-ku, Tokyo Max Co., Ltd. (72) Koji Kubo 6-6-6 Nihonbashi-Hakozakicho, Chuo-ku, Tokyo Max Co., Ltd. (72) Inventor Hiroki Yamamoto 6-6 Nihonbashi Hakozakicho, Chuo-ku, Tokyo Max Co., Ltd.

Claims (1)

[Claims] 1. A blowback chamber is formed by accommodating an air cylinder in a cylinder housing portion of a nailing machine housing and closing a cylindrical space between an outer peripheral surface of the air cylinder and an inner wall surface of the cylinder housing portion. A switching valve that connects the front portion of the air cylinder and the blowback chamber and that selectively switches the rear air chamber of the air cylinder to the exhaust port or the pressure air chamber in the housing, and operates the switching valve. Then, the piston of the air cylinder is driven to inject the nail supplied in the nose block of the housing by the driver rod connected to the piston, and the compressed air accumulated in the blowback chamber in the forward stroke of the piston is used. In an air nailer that retracts the piston to return to the standby position, A cylindrical space between the outer peripheral surface of the air cylinder (27) and the inner wall surface of the cylinder housing part (23) is defined by a cylindrical partition wall (2).
6) is divided into coaxial double cylindrical spaces, which are each closed, and the inner space is made to communicate with the front part of the air cylinder (27) to form a blowback chamber (29), and the outer space is switched to the above. An air nailing machine characterized in that an exhaust chamber (30) is provided with an exhaust port (34) connected to an exhaust port (37) of a valve (35) and communicating the outer space with the atmosphere.