JPH09300237A - Head valve seal device for driving machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving machine having a stable continuous hammering speed by keeping a seal at a constant position for a cylinder and a head valve, and reducing the fluctuation of the pressure receiving area of the head valve attributable to the dispersion of the seal position. SOLUTION: A fine projection 24 is formed at least on one of the opposed surfaces of a cylinder 3 and a head valve 6 in close contact, thereby keeping a constant seal position for the cylinder 3 and the head valve 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head valve sealing device for a driving machine, in which the head valve and the end surface of the cylinder can be reliably sealed and the pressure receiving area can be kept constant.

[0002]

2. Description of the Related Art As a conventional example of a multiple impact type driving machine, Japanese Patent Application Laid-Open No. 5-16077 filed by the applicant of the present invention is mentioned.
This will be described with reference to FIG. When the nail 22 is inserted into the nail guide 23 and the tip of the nail 22 is pressed against the material 24 to be driven, the head of the nail 22 pushes up the push lever 26 and unlocks the trigger 25. When the trigger 25 is pulled in this state, the trigger valve 11 operates and the compressed air in the head valve upper chamber 8 is released to the atmosphere via the air passages 12 and 10. Therefore, the head valve 6 rapidly rises, compressed air flows into the upper portion of the piston 4, the piston 4 and the driver blade 20 rapidly descend, and the nail 22 in the nail guide 23 is driven into the driven material 24.

The air below the piston 4 of the cylinder 3 flows into the return air chamber 14 through the communication hole 17. When the piston 4 passes through the communication hole 19 having the check valve 18, the compressed air above the piston 4 of the cylinder 3 also passes through the communication hole 19.
The return air flows into the air chamber 14. When a part of the compressed air that has flowed into the return air chamber 14 reaches the repetitive valve lower chamber 13 via the air passage 15, the repetitive valve 27 moves up and shuts off the air passage 10 and the air passage 12.

Since the head valve upper chamber 8 and the pressure accumulating chamber 2 are communicated with each other through the air passage 16 provided vertically penetrating the head valve 6, the compressed air in the pressure accumulating chamber 2 flows in,
The pressure in the head valve upper chamber 8 and the air passage 10 increases. The repetitive valve 27 does not descend because the upper pressure receiving area S1 is smaller than the lower pressure receiving area S2, and thus the air passage 1
The state where 0 and the air passage 12 are blocked is maintained.

The head valve 6 is lowered by the pressing force of the head valve spring 28 as the pressure of the head valve upper chamber 8 rises, shuts off the cylinder 3 and the pressure accumulating chamber 2, and removes the air above the piston 4 in the cylinder 3 from the exhaust valve 7. Release to atmosphere. Therefore, the compressed air in the return air chamber 14 causes the piston 4 to return to the initial top dead center. Due to the expansion of air, the pressure of the return air chamber 14 becomes low, the pressure of the communicating repetitive valve lower chamber 13 also becomes low, and the pressure of the repetitive valve upper chamber 9 causes the repetitive valve 27 to descend and the head valve upper chamber 8 And the compressed air in the air passage 10 is released to the atmosphere via the trigger valve 11. Since the passage cross-sectional area of the air passage 16 is set to be sufficiently smaller than the passage cross-sectional areas of the air passages 10 and 12, the amount of discharge from the trigger valve 11 is larger than that of the air filling from the air passage 16 and the head valve above Room 8
Pressure drops rapidly. When the pressure in the head valve upper chamber 8 drops, a series of operations such as raising and driving the head valve 6 are performed again as described above. These series of operations are trigger 2
It is automatically repeated while 5 is operated, and the nail 22 is driven into the driven material 24 by a large number of repeated impacts.

When the trigger 25 is released and the trigger valve 11 is returned, the head valve 6 and the upper end surface of the cylinder 3 are sealed. These sealing surfaces are smooth so that they do not leak compressed air and adhere closely. When the trigger 25 is pulled and the trigger valve 11 is opened, as described above, the pressure in the head valve upper chamber 8 rapidly decreases, and the pressure in the pressure accumulating chamber 2 applied to the area S3 becomes larger than the pressing force of the head valve spring 28. The head valve 6 rapidly rises and the compressed air in the pressure accumulating chamber 2 flows into the upper side of the piston 4 of the cylinder 3.

[0007]

In the above-described driving machine, when the head valve 6 is made of a flexible material such as rubber and the cylinder 3 is made of a non-flexible material such as aluminum,
The flexible head valve 6 is brought into pressure contact with the head valve 6 and the cylinder 3 by the pressure of the head valve upper chamber 8 and the pressure of the head valve spring 28 so that the head valve 6 and the cylinder 3 are in close contact with each other. However, when enlarged microscopically, the sealing surfaces of the head valve 6 and the cylinder 3 are not entirely in contact,
As shown in FIG. 5, there is also a case where a part is pressed. If the seals are not uniform and thus vary, the area S3 changes. As a result, the force for pushing up the head valve 6 varies depending on the driving machine, and there is a problem that the continuous striking speed varies depending on the driving machine. Head valve 6
When the close contact state of the cylinder 3 becomes familiar, there is a problem that the continuous striking speed changes even with the same driving machine.

In order to solve the above-mentioned problem, as shown in FIG. 6, it is conceivable to mount a seal member 29 such as an O-ring on the seal surface of the cylinder 3 or the head valve 6, but with such a structure, the parts are There is a problem in that the number increases, the cost increases, and the assembly man-hour increases. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a driving machine capable of stable quality, easy assembling and cost reduction.

[0009]

The above object can be achieved by providing minute projections on at least one of the sealing surfaces of the head valve and the cylinder.

[0010]

In the driving machine constructed as described above, the convex portion of the head valve is in close contact with the end surface of the cylinder for sealing. When the head valve is closed, the contact surface pressure becomes higher than the conventional seal surface due to this convex portion, and the contact surface is always in close contact with the end surface of the cylinder. Therefore, the change in the area S3 due to the variation in the seal is extremely small, and the continuous impact speed is high. Can be stabilized.

Further, since the convex portion is brought into close contact with the cylinder with a high contact surface pressure from the beginning of the assembling, the continuous striking speed does not change due to familiarity.

Further, since the head valve and the convex portion are integrated, easy assembling and cost reduction can be achieved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION One embodiment of the present invention is shown in FIGS. Compressed air from a compressor (not shown) is accumulated in the pressure accumulating chamber 2 of the driving tool body 1. A cylindrical cylinder 3 is provided in the driving tool body 1, and a piston 4 is provided in the cylinder 3 so as to be vertically slidable. A piston ring 5 is provided on the outer circumference of the piston 4 to seal between the cylinder 3 and the piston 4. A head valve 6 is provided above the cylinder 3, and when the head valve 6 rises, the upper end of the cylinder 3 opens and the accumulator 2 communicates with the upper side of the piston 4 of the cylinder 3, and the exhaust valve 7 closes. Cylinder 3
When the upper end is closed and the exhaust valve 7 is opened, the upper side of the piston 4 of the cylinder 3 communicates with the atmosphere. The head valve upper chamber 8 communicates with the repetitive valve upper chamber 9 via the air passage 10, and the repetitive valve upper chamber 9 and the trigger valve 11 communicate with each other via the air passage 12. Repetitive valve lower chamber 13 and return air chamber 14
Communicate with each other via the air passage 15. The head valve 6 is provided with an air passage 16 penetrating vertically, and is closed at the upper end of the cylinder 3 when the head valve 6 descends, and the head valve upper chamber 8 and the pressure accumulating chamber 2 communicate with each other when the head valve 6 rises. The passage cross-sectional area of the air passage 16 is set sufficiently smaller than the passage cross-sectional areas of the air passage 10 and the air passage 12. A communication hole 19 having a communication hole 17 and a check valve 18 is provided in the cylinder 3 so as to communicate with the return air chamber 14 as in the conventional driving machine.

A piston 4 is provided at the nail ejection portion of the driving machine body 1.
And a blade guide 21 for guiding the driver blade 20 integrally connected with the blade guide 21 for guiding the nail 22.
A nail guide 23 that slides up and down along the nail and a nail 22 are inserted into the nail guide 23, and the tip of the nail 22 is driven into the driven material 2.
There is provided a push lever 26 which is pushed by the blade guide 21 and ascends while being guided by the blade guide 21 to release the lock of the trigger 25. Cylinder 3 of head valve 6
As shown in FIG. 2 and FIG. 3, a ring-shaped convex portion 24 having a minute height is provided on the surface opposite to. When the head valve 6 is closed, the pressure on the contact surface increases due to the convex portion 24, and the convex portion 24 comes into close contact with the upper end surface of the cylinder 3.
The change of the area S3 due to the variation of the seal becomes very small, and the continuous impact speed can be stabilized. Further, since the convex portion 24 comes into close contact with the cylinder 3 with a large contact surface pressure from the beginning of assembly, there is no change in the continuous striking speed due to familiarity. Furthermore, since the convex portion 24 is formed integrally with the head valve 6, the assembly is facilitated and the cost can be reduced.

The driving operation by the driving machine having the above-mentioned structure is shown in FIGS.
This will be described with reference to FIG. When the nail 22 is inserted into the nail guide 23 and the tip of the nail 22 is pressed against the driven material 24, the head of the nail 22 pushes up the push lever 26 and the upper end of the push lever 26 unlocks the trigger 25. When the trigger 25 is pulled in this state, the compressed air in the head valve upper chamber 8 is released from the trigger valve 11 via the air passages 10 and 12, and due to the pressure of the pressure accumulating chamber 2 applied to the area S3,
The head valve 6 rises and the compressed air suddenly rises.
And the driver blade 20 integrated with the piston 4 suddenly descends. Driver blade 2
0 drives the nail 22 in the nail guide 23 while descending to the bottom dead center of the piston 4.

When the compressed air that has flowed into the return air chamber 14 flows into the repetitive valve lower chamber 13 through the air passage 15, the repetitive valve upper chamber 9 is at atmospheric pressure, so that the repetitive valve 27 ascends and the air passage 10 and the air The passage 12 is cut off. Since the head valve upper chamber 8 and the pressure accumulating chamber 2 are communicated with each other via the air passage 16, the compressed air in the pressure accumulating chamber 2 flows in and the pressure in the head valve upper chamber 8 and the air passage 10 increases. Since the upper pressure receiving area S1 is smaller than the lower pressure receiving area S2, the repetitive valve 27 keeps the air passage 10 and the air passage 12 blocked.

The head valve 6 is lowered by the pressing force of the head valve spring 28 as the pressure of the head valve upper chamber 8 rises, shuts off the cylinder 3 and the pressure accumulating chamber 2, and removes the air above the piston 4 of the cylinder 3 from the exhaust valve 7. Released into the atmosphere. As a result, the compressed air in the return air chamber 14 causes the piston 4 to return to the initial top dead center. Due to the expansion of air, the pressure in the return air chamber 14 becomes low, and the pressure in the communicating repetitive valve lower chamber 13 also becomes low. Repeat valve upper chamber 9
The repetitive valve 27 is lowered by the pressure of the trigger valve 11 and the compressed air in the head valve upper chamber 8 and the air passage 10 is moved to the trigger valve 11
To the atmosphere via.

The cross sectional area of the air passage 16 is equal to that of the air passage 1.
0, since it is set sufficiently smaller than the passage cross-sectional area of the air passage 12, the trigger valve 1
The discharge from 1 increases, and the pressure in the head valve upper chamber 8 drops rapidly. When the pressure in the head valve upper chamber 8 drops, a series of operations such as raising and driving of the head valve 6 are performed again as described above. By repeatedly hitting many times,
The nail 22 is driven into the driven material 24.

Contrary to the above-described operation, when the trigger 25 is released, the compressed air in the pressure accumulating chamber 2 is filled from the trigger valve 11 into the upper chamber 8 of the head valve through the air passages 12 and 10, as shown in FIGS. As shown in, the head valve 6 descends, and the piston 4 stops the driving operation at the position where it has returned to the top dead center. The push lever 26 and the nail guide 23 are lowered to lock the trigger 25 as shown in FIG.

FIG. 7 shows another embodiment of the present invention in which the convex portion 24 is provided on the cylinder 3 side.
Even if it is provided on the side, the same effect as that of the above embodiment can be obtained.

[0021]

As described above, according to the present invention, the convex portion is provided on at least one of the facing surfaces of the head valve and the cylinder, and the head valve and the end surface of the cylinder are brought into close contact with each other via the convex portion. The position is always constant, the change of the area S3 due to the variation of the seal is very small, the continuous impact speed can be stabilized, and the continuous impact speed does not change due to familiarization.
Further, since the convex portion is integrated with the head valve or the cylinder, the assembly is facilitated and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a driving machine adopting a sealing device of the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1 showing a time when a head valve is descending.

FIG. 3 is an enlarged view of a main part of FIG. 1 showing a time when a head valve is raised.

FIG. 4 is a sectional view showing an example of a conventional driving machine.

FIG. 5 is an enlarged view of a main part of FIG. 4;

FIG. 6 is an enlarged view of a main part showing an example of a configuration that can be considered in order to solve the drawback of FIG.

FIG. 7 is an enlarged cross-sectional view of a main part showing another embodiment of the present invention.

[Explanation of symbols]

1 is a driver main body, 3 is a cylinder, 4 is a piston, 6 is a head valve, and 24 is a convex portion.

Claims (1)

[Claims] 1. A pressure accumulating chamber for accumulating compressed air, a piston reciprocally provided in a cylindrical cylinder, and compressed air in the pressure accumulating chamber is introduced into the atmosphere above the piston in the cylinder. A head valve sealing device for a driving machine, comprising: a driving machine having a head valve that alternately performs an operation, wherein a minute convex portion is provided on at least one of the sealing surfaces of the head valve and the cylinder in close contact with each other.