JPH0645341Y2 - Nailer safety device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a pneumatic pneumatic nailing machine which is driven based on the operation of a contact valve which is interlocked with the operation of pressing a contact member against a material to be driven together with the operation of a trigger.

[0002]

2. Description of the Related Art In a nailing machine that impacts a striking piston with compressed air to strike a nail, a nailing valve that operates by pulling a trigger lever and an operation that presses a contact member against a material to be driven operate. There is known a safety device in which a nailing machine is activated by directly connecting the contact valve with the contact valve and actuating both valves (US Pat. No. 3,288,339). This is one in which a trigger valve and a contact valve are communicated with each other via an air flow path, and when both valves are brought into an operating state together, a main valve that drives a nailing machine is activated.

As described above, the device using the contact valve has a problem that it takes time to exhaust the compressed air from the contact valve, and the operation response is deteriorated.
In order to improve the operation response, it is necessary to discharge the compressed air in the communication passage connecting the trigger valve and the contact valve in a short time, so that the exhaust area is large and the operation stroke must be small from the viewpoint of workability. is there. For this reason, a large-diameter face seal valve is used as the contact valve, and compressed air is usually applied to the back surface of the contact valve to operate the contact valve against this air pressure at startup. There is.

However, when a large amount of compressed air pressure acts on the back surface of a face seal valve having a large diameter exhaust port, a large force is required to operate the valve, which tends to deteriorate the nailing work.

Although it is easy to reduce the effect of the air pressure applied to the valve by using the differential valve, the valve is actuated by the effect of the vibration acting on the nailing machine and the nail is erroneously shot. Therefore, it is not suitable as a safety device for a nail driver.

[0006]

The object of the present invention is to solve the above-mentioned drawbacks and to maintain the closed position by the action of air pressure during normal operation to prevent accidental firing due to vibration of the nailing machine. It is an object of the present invention to provide a safety device for a compressed air type nailer that can be operated with a small operating force by releasing the air pressure during a nailing operation.

[0008]

In order to achieve the above object, a safety device for a pneumatic pneumatic nailing machine according to the present invention comprises a starting valve for actuating a main valve of the nailing machine and a front projection of a nose portion. A nailing machine, comprising: a contact valve that is operated by abutting on a contact member that is disposed and that opens and closes a communication passage that communicates with the trigger valve to the atmosphere, wherein the contact valve is formed in a hollow shape; An exhaust valve that is operated by the contact member to open and close a communication passage communicating with the trigger valve to the atmosphere, and a piston portion formed in the exhaust valve are slidably accommodated,
A valve cylinder having a chamber formed above the piston portion, a small hole for constantly connecting the inside of the valve cylinder to a compressed air supply source, and a slidably accommodated inside the hollow portion of the exhaust valve, Also has an operation stem protruding so as to be close to the contact member, and a release valve for opening and closing the inside of the chamber with respect to the atmosphere.

[0009]

According to the above construction, when the lower end of the contact member is pressed against the driven material, the upper end surface of the contact member first comes into contact with the operating stem of the release valve and pushes it up. This opens the flow path between the chamber and the exhaust port, and the compressed air in the chamber is exhausted. In this case, compressed air is supplied from the micro holes into the chamber, but since the exhaust flow rate is larger than the inflow amount, the pressure inside the chamber drops, and the air pressure acting downward on the upper end of the exhaust valve disappears. . Therefore, the force required for the contact member to move the exhaust valve upward after the release valve is small,
The operation is easy.

On the other hand, normally, since the pressure of the compressed air introduced into the chamber through the minute holes acts downward on the upper end surface of the exhaust valve, it may be affected by vibrations due to movement of the nail driver. Exhaust valve does not operate and safety can be sufficiently secured.

Further, since the release valve only exhausts the air in the chamber, it requires only a minute stroke and a small diameter, so that its operating force does not become large. After the release valve operates, air pressure does not act on the release valve.Therefore, by setting the difference between the diameter of the sliding seal part of the exhaust valve with the valve cylinder and the effective diameter of the exhaust port seal part, The operation force can be set in any way.

As described above, even if the operation response is improved by setting the opening area of the exhaust valve large, the operation load of the valve does not increase and a nailing machine with good operability can be obtained.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a main part of a housing of a compressed air type nail driving machine. In the housing, an air chamber a connected to a compressed air supply source and a hammer driving driver 1 are integrally connected to a striking piston. 2, a striking cylinder 3 slidably accommodating the striking cylinder 3 and the striking cylinder 3 in the air chamber a.
And an annular main valve 4 that opens and closes with respect to
When the main valve 4 moves to the position where the air supply port 5 is opened (the position shown by the dotted line in the figure), compressed air is supplied from the air chamber a, the striking piston 2 is driven, and the driver 1 drives in a nail.

The main valve 4 is slidably accommodated in a main valve control chamber 6 and moves to an exhaust position and an air supply position by supplying and discharging compressed air in the main chamber a to and from the control chamber. The operation is controlled by the cooperation of the starting valve 7 and the contact valve 8.

The starting valve 7 is a hollow upper valve stem 9
And a lower valve stem 10 whose upper half is slidably accommodated in the upper valve stem 9, and the upper part of the upper valve stem 9 connects the main valve control chamber 6 to the air chamber a.
To a lower position connected to the exhaust hole 40, and a lower part is slidably accommodated in a valve cylinder 11 which slidably accommodates the lower valve stem 10. The lower valve stem 10 is constantly urged downward by a spring 12, and the lower end thereof has a trigger lever 13 at its lower end.
And is moved up and down by manual operation of the trigger lever 13.

A pilot chamber 14 is formed below the lower end of the upper valve stem 9, and the pilot chamber 14 communicates with the air chamber a by means of a through hole 15 formed in the side wall of the upper valve stem 9. It communicates with the contact valve 8 via the passage 16. In addition,
A space between the through hole 15 and the pilot chamber 14 is opened and closed by a seal ring 41 at the upper center of the lower valve stem 10 coming into contact with and separating from the inner wall of the lower end of the upper valve stem 9.

Next, as shown in FIG. 2, the contact valve 8 is operated by a contact member 17 which is operated in contact with the material 30 to be driven, and is arranged in the valve housing 17 and the upper end is closed. A valve cylinder 18, an exhaust valve 19, an intake valve 20, and a release valve 21, which are slidably arranged in the valve cylinder 18, and communicate with the start valve 7 via a communication passage 16. .

The contact member 17 is normally provided at the tip of the nailing machine and protrudes from the tip of the nose portion 22 having an injection port, and is pressed against the driven material 42 to move relative to the nose portion 22. To do.

The exhaust valve 19 is in the form of a sleeve having a hollow portion in the center, is formed to have a large diameter, and has a piston portion 23 that slides in the valve cylinder 18 on the upper portion, and at the time of sliding, it is attached to the lower side surface. The seal ring 24 provided around the valve housing 17 is brought into contact with and separated from an annular seal surface 25 formed inside the lower end of the valve housing 17, so that the exhaust port 26 formed below the valve housing 17 and the communication passage 16 are separated from each other. It is configured to open and close to the atmosphere. Also, the exhaust valve 1
The spring 9 provided between the valve cylinder 18 and the lower end of the valve cylinder 18 is always biased in the direction of closing the communication passage 16.

The intake valve 20 is arranged above the exhaust valve 19,
An annular wall 27 is formed on the upper part, and a hollow stem 29 is integrally formed on the lower part by narrowing to a small diameter. The hollow stem 29 penetrates the hollow portion of the exhaust valve 19 and projects downward. When reciprocating in the valve cylinder 18, the intermediate seal ring 30 abuts and separates from the inner wall of the valve cylinder 18 to open and close between the communication passage 16 and the air chamber a. ing.

A release chamber 31 is formed between the upper end recess 28 of the intake valve 20 and the valve cylinder 18. The release chamber 31 is always in communication with the air chamber a through a passage 32 formed in the side wall of the valve cylinder 18 and a small hole 33 formed in the upper annular wall 27 of the intake valve 20.

Next, the release valve 21 is disposed in the release chamber 31 and is constantly urged downward by the spring 34. Further, a valve ring 35 is provided in the upper part, the hollow stem 29 of the intake valve 20 is inserted therethrough, and the operation stem 21a protruding in the lower part so as to be closer to the contact member 17 than the exhaust valve 19 is formed. . Further, a seal ring 36 is provided between the inner bottom surface of the annular wall 27 of the intake valve 20 and the valve ring 35 of the release valve 21, and the valve ring 35 contacts the seal ring 36 when reciprocating. By separating,
The release chamber 35 is opened and closed with respect to the exhaust port 26.

Each spring 2 of the exhaust valve 19 and the release valve 21
7, 34 are omitted in FIG.

In the above structure, before the contact striking operation, as shown in FIG. 2, the exhaust valve 19, the intake valve 20 and the release valve 21 constituting the contact valve 8 are located below,
Since the flow path between the communication passage 16 and the exhaust port 26 is closed, the release chamber 31 is filled with compressed air, and the flow path between the air chamber a and the communication passage 16 is open, the compressed air is It is full within 16. On the other hand, as shown in FIG. 1, the upper valve stem 9 is pushed upward by the compressed air supplied to the pilot chamber 14 through the through hole 15 to close the exhaust hole 40, and the compressed air is supplied into the main valve control chamber 6. This air pressure urges the main valve 4 to the exhaust position. At this time, the striking piston 2 does not move. Further, the lower valve stem 10 is positioned below by the force of the spring 12.

Next, when the trigger lever 13 is pulled, as shown in FIG. 3, the lower valve stem 10 is pushed up, so that the space between the pilot chamber 14 and the through hole 15 is blocked, and compressed air to the pilot chamber 14 is blocked. The supply is stopped and at the same time the pilot chamber 14 is in communication with the passage 16. However, since the passage 16 is filled with the compressed air via the contact valve 8, the inside of the pilot chamber 14 is not reduced in pressure and the upper valve stem 9 remains held at the same position as in FIG.

Thereafter, when the contact member 17 is pressed against the material 42 to be driven, the contact member 17 moves relative to the nose portion 4 as shown in FIG. 4, and the operation stem 21a of the release valve 21 is first moved. Since it hits the lower end and pushes it up, the valve ring 35 and the seal ring 3
6 is released, the compressed air in the release chamber 31 is opened to the exhaust port 26, the intake valve 20 is subsequently pushed up, and the flow path between the air chamber a and the communication passage 16 is closed,
Further subsequently, the exhaust valve 19 is actuated, the seal ring 24 at the lower end is separated from the annular seal surface 25, the seal between them is released, and the flow passage between the communication passage 16 and the exhaust port 26 is instantly opened. Moreover, since the opening area of the exhaust valve 19 is set large, a large amount of compressed air is instantaneously exhausted from the communication passage 16. As a result, the pressure in the pilot chamber 14 is reduced, and the upper valve stem 9 moves downward as shown in FIG. As a result, the upper valve stem 9 connects the exhaust hole 40 and the main valve control chamber 6 to move the main valve 4 upward. Compressed air is introduced above the striking piston 2 from the air supply port 5, and the striking piston 2 is driven to drive out the nails supplied into the nose portion 4.

When the contact member 17 is separated from the material 42 to be driven after nailing, the exhaust valve 19, the intake valve 20 and the release valve 21 of the contact valve 8 move downward again as shown in FIG. The flow passage between the communication passage 16 and the exhaust port 26 is closed, the flow passage between the air release chamber 31a and the communication passage 16 is opened, and compressed air is supplied into the pilot chamber 14 through the communication passage 16. Therefore, the upper valve stem 9 moves upward again to close the exhaust hole 40 and move to the position where the air chamber a and the main valve control chamber 6 are opened as shown in FIG. Therefore, the main valve 4 is connected to the air supply port 5
Is moved to the closed position, the compressed air in the striking cylinder 3 is exhausted, and the striking piston 2 is returned to ascend.

By the way, as shown in FIG. 4, when the lower end of the contact member 17 is pressed against the driven material 42, the upper end surface of the contact member 17 first contacts the lower end of the operation stem 21a of the release valve 21 and pushes it up. As a result, the release chamber 31 is opened to the exhaust port 26, and the compressed air in the release chamber 31 is exhausted. In this case, compressed air is supplied from the small holes 33 into the release chamber 31, but since the exhaust flow rate is larger than the inflow amount, the pressure inside the release chamber 31 drops and acts downward on the upper end of the exhaust valve 19. The air pressure that was used is lost. Therefore, after the operation stem 21a, the contact member 17 is continuously connected to the exhaust valve 19
The force to move it upwards when hitting is small,
Easy to operate.

On the other hand, normally, the release chamber 3
Since the pressure of the compressed air introduced through the small hole 33 into the inside of No. 1 acts on the upper end surface of the exhaust valve 19 downward, the exhaust valve 19 may be activated by vibration due to movement of the nailing machine or the like. There is no safety.

Further, since the release valve 21 only discharges the compressed air in the release chamber 31, it requires only a minute stroke and a small diameter is sufficient. Therefore, the force for operating the release valve 21 can be small. Therefore, even if the opening area of the exhaust valve 19 is set large to improve the operation response, the operating load of the contact valve 8 does not increase, and a nailing machine with good operability can be obtained.

Incidentally, the contact valve 8 may have a structure in which the intake valve 20 is removed as shown in FIG. 5, and a small hole 33 connecting to the air chamber a may be formed in the valve cylinder. In the figure, the same reference numerals as those in FIGS. 2 and 4 denote the same parts.

In this case, normally, as shown in the figure, the release valve 21 cooperates with the exhaust valve 19 to close the release chamber 31 to the atmosphere, and the compressed air flowing in through the small hole 33 is released. The air pressure that accumulates in the chamber 31 is released by the release valve 2.
1 and the exhaust valve 19 and the upper surface to close the exhaust valve 19.

When the contact member 17 is pressed, as shown in FIG. 6, first, the release valve 21 is pushed up by hitting the lower end of the operation stem 21a, and the air in the release chamber 31 is released to the atmosphere. Small hole 33 in the valve cylinder
Although compressed air flows in through the chamber, the pressure inside the release chamber 31 becomes substantially equal to the atmospheric pressure because the amount of discharge is larger.

Subsequently, by pressing the contact member 17, as shown in FIG. 7, the exhaust valve 19 is pushed up to connect the communication passage 16 communicating with the starting valve 7 to the atmosphere, and the nailing machine is driven. At this time, since the compressed air from the trigger valve acts only on the outer diameter difference portion of the piston portion 23, the exhaust valve moves lightly and is easy to operate.

Compressed air is supplied to the pilot chamber 14 of the starting valve 7 in this case from the air chamber a through the through hole 15 formed in the upper valve stem 9.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a starting valve and its peripheral portion of a safety device for a compressed air nailer according to the present invention.

FIG. 2 is a sectional view of a contact valve of the safety device.

FIG. 3 is an explanatory view of an operation mode of the start valve.

FIG. 4 is an explanatory view of an operating mode of the contact valve.

FIG. 5 is a cross-sectional view of another example of the contact valve of the safety device.

FIG. 6 is an explanatory cross-sectional view of the contact valve during operation.

FIG. 7 is an operation explanatory view of the contact valve.

[Explanation of symbols]

 a Air chamber 2 Strike piston 3 Strike cylinder 4 Main valve 8 Contact valve 17 Contact member 19 Exhaust valve 20 Intake valve 21 Release valve 31 Release chamber 33 Small hole

Claims (1)

[Scope of utility model registration request] 1. A starting valve for operating a main valve of a nailing machine and a contact member which is operated by abutting a contact member projectingly arranged in front of a nose portion and opens and closes a communication passage communicating with the trigger valve to the atmosphere. A nailing machine comprising a contact valve, wherein the contact valve is formed in a hollow shape and is operated by the contact member to open and close a communication passage communicating with the trigger valve to the atmosphere, and the exhaust gas. A valve cylinder in which a piston portion formed in the valve is slidably accommodated and a chamber is formed above the piston portion, a small hole for constantly connecting the inside of the valve cylinder to a compressed air supply source, and the exhaust valve The operation stem is slidably accommodated in the hollow portion and protrudes closer to the contact member than the exhaust valve. A safety device for a nailing machine, comprising: a release valve that opens and closes the inside of the chamber with respect to the atmosphere.