JPH0641813Y2 - Safety device for compressed air nailer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to the safety of a compressed air type nailer driven based on the operation of a contact valve that is interlocked with the operation of a trigger and the operation of pressing a contact member against a material to be driven. It relates to the device.

(Prior art and its problems) In a nailing machine that impacts a striking piston by compressed air to strike a nail, pulling operation of a trigger lever arranged in the vicinity of a grip formed in a housing and nail firing There is provided a safety device that activates the nail driving machine only when the contact operation with the material to be driven by the contact member arranged near the tip of the operating nose portion is performed at the same time.

The usual safety device is that the upper end of the contact member protruding from the tip of the nose part is extended to the vicinity of the trigger lever via the contact arm, and the trigger valve for starting is activated by the upward movement of the contact arm and the operation of the trigger lever. Is configured to operate.

When the contact arm at the upper end of the contact member is extended to the trigger lever in this way, it is necessary to form a sliding guide for the contact arm and to secure a space for disposing the contact arm. It makes the structure of the complicated and causes a trouble in driving,
It may cause a failure. Further, it is necessary to lengthen the operation stroke of the contact arm, which deteriorates the operation characteristics of the nail driver.

On the other hand, as a technique different from the above, there is known a safety device that activates a contact valve directly connected to a trigger valve for activation by actuation of a contact member and activates a nailing machine by actuation of 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.

However, in the operation mode of the nail driver, when the contact member is hit against the surface of the material to be nailed while maintaining the state where the trigger lever is first operated, so-called contact hammering is performed, the contact member is It is difficult to always press accurately against the material to be driven. For example, when the contact member is immediately separated after being pressed against the material to be driven, the contact valve is maintained for a very short time. If the operating time of the contact valve is short, the main valve will be actuated, and the main valve will be returned immediately after the actuation of the drive piston. There are problems such as insufficient driving, and insufficient storage of compressed air in the chamber for returning the piston so that the piston cannot be returned.

(Object of the Invention) The present invention solves the above-mentioned drawbacks, and particularly, in a nailing machine equipped with a manually operated trigger valve and a contact valve operated by being pressed against a material to be driven, when driving by a contact operation. It is an object of the present invention to provide a safety device for a compressed air type nailer that delays the return operation of the contact valve to output a reliable operation signal to the main valve.

(Means for Achieving the Purpose) In order to achieve the above-mentioned object, a safety device for a compressed air nailing machine according to the present invention includes a striking cylinder arranged in a housing and a slidable arrangement in the cylinder. Striking piston integrally provided with a nail driving driver, an air chamber constantly connected to a compressed air supply source, and a main valve for selectively connecting the striking piston of the striking cylinder above the striking piston to the air chamber and the atmosphere. And a pilot chamber having a pilot valve stem for selectively connecting a main valve control chamber controlling the operation of the main valve to an air chamber and an atmosphere, and a pilot chamber containing one end of the pilot valve stem. Operated by a pilot valve that is operated by supplying and discharging compressed air to and from the contact member that is operated in contact with the material to be driven. And a contact valve that selectively connects a communication passage communicating with the pilot chamber to the exhaust port and the air chamber, and a communication lever that is operated by a manually operated trigger lever to open and close the communication passage communicating the pilot chamber and the contact valve. A contact valve having a trigger valve stem, the contact valve being disposed in the valve housing and having an upper end closed; and an exhaust port formed in the valve housing and disposed in the valve cylinder. A sleeve-shaped exhaust valve that opens and closes a flow path to and from the communication passage, and a hollow stem that penetrates the hollow portion of the exhaust valve and projects downward are integrally provided and disposed above the exhaust valve in the valve cylinder. And an intake valve that opens and closes a flow path between the communication passage and the air chamber, and a hollow stem of the intake valve. An operation stem that is inserted into the delay chamber defined between the valve cylinder and the upper end of the intake valve, and that opens and closes a flow path between the delay chamber and the exhaust port. And the delay chamber is always in communication with the air chamber via a flow path having a minute diameter.

(Operation and Effect of the Invention) According to the above configuration, when the trigger valve stem is actuated by pulling the trigger lever, the flow path between the pilot chamber and the communication passage opens. Then, when the contact member is pressed against the material to be driven, the exhaust valve, the intake valve, and the operation stem operate. Since the communication passage is connected to the exhaust port by the operation of the exhaust valve, the pilot chamber is depressurized and the pilot valve stem operates to connect the main valve control chamber to the atmosphere to operate the main valve. As a result, the striking piston is driven and the nail is driven into the material to be driven.

When the contact member is separated from the material to be driven, the exhaust valve of the contact valve and the operation stem immediately return and move, closing the flow path between the communication passage and the exhaust port, and closing the flow path between the delay chamber and the exhaust port. close.

By the way, since the delay chamber is located above the intake valve, compressed air must be supplied into the delay chamber so that the internal pressure becomes sufficiently high for the intake valve to move back. However, since the compressed air is supplied from the air chamber through the flow path having a small diameter, the compressed air is delayed in the delay chamber. As a result, the supply of compressed air from the air chamber to the pilot chamber via the communication passage is delayed, the return movement of the pilot valve stem is delayed, and the operation of connecting the main valve control chamber to the air chamber is delayed.

As described above, the pilot valve operates only after waiting for the pressure in the delay chamber to become sufficiently high to operate the intake valve after the predetermined time determined by the volume of the delay chamber and the minute diameter passage has elapsed. During that time, the main valve control chamber is opened to the atmosphere, the main valve control chamber is sufficiently exhausted, and the main valve is reliably kept open for a predetermined time.

Therefore, delay the pilot valve stem even if the contact valve is kept in an operating state for an extremely short time, such as when the contact member is immediately separated after being pressed against the material to be driven. Since it can be restored, the main valve can be fully operated.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 shows a recoilless compressed air type nailer. The nailer includes a housing 1 and a grip 2 each having an air chamber a connected to a compressed air supply source, and a housing. A nose portion 4 having an ejection port for a nail 3 is provided on the lower end side of the nail 1, a nail supply magazine 5 is provided between the nose portion 4 and the grip 2, and the housing 1
A movable striking cylinder 6 which slides in the axial direction of the nose portion 4 is provided in the interior of the casing, and the upper end of the movable striking cylinder 6 is closed by an upper wall 7, and inside thereof, a driver sliding in the injection port. A striking piston 9 integrally connected with 8 is slidably provided, and a main valve 10 selectively selects between the upper wall 7 of the movable striking cylinder 6 and the upper portion of the striking piston 9 to the air chamber a and the atmosphere. The striking piston 9 is driven by switching connection.

The housing 1 is double formed by an outer shell 1a and a fixed sleeve 1b provided inside the outer shell 1a, and the movable striking cylinder 6 is fixed sleeve 1b arranged inside the housing 1.
It is slidably held in the air chamber a while being separated from the air chamber a. An opening 14 is formed on the peripheral wall of the fixed sleeve 1b, which is always in communication with the air supply / exhaust port 13 formed on the peripheral wall near the upper end of the movable striking cylinder 6, and the main valve 10 is provided on the outer peripheral side of the fixed sleeve 1b. An annular main valve control chamber 12 that slidably accommodates is formed, and in the main valve control chamber 12, a fixed sleeve 1b and a sleeve-shaped main valve 10 that is slidable are arranged.

The main valve 10 is at an exhaust position where the supply / exhaust port 13 formed in the upper part of the movable striking cylinder 6 is connected to the exhaust hole 11 at the upper end of the housing 1 from the opening formed in the upper part of the fixed sleeve 1b (solid line in FIG. 5). Position) and the air supply / exhaust port 13 from the opening 14 to the air supply position (dotted line position in the figure) connecting to the air chamber a.

Next, the compressed air in the main chamber that acts on the portion exposed in the main valve main chamber a and the control chamber
The compressed air supplied to and discharged from the inside 12 moves to the exhaust position and the supply position, and the drive control of the main valve 10 is performed by the pilot valve 18 provided between the housing 1 and the grip 2.

When the pilot valve 18 is in the upper position (the position shown in FIG. 5) due to the vertical movement of the valve stem 19, the inside of the main valve control chamber 12 is connected to the air chamber a and the exhaust hole 15 is closed. At the same time, when in the lower position, the main valve 10 is driven by disconnecting the main valve control chamber 12 from the air chamber a and connecting the control chamber 12 to the exhaust hole 15. The lower end side of the pilot valve stem 19 is slidably accommodated in the pilot chamber 20 and operates as described above by supplying / discharging compressed air into / from the pilot chamber 20.

The pilot chamber 20 is formed in a trigger valve provided in the vicinity of the trigger lever 29, communicates with the air chamber a through a small hole 21 formed in the side wall of the pilot valve stem 19, and also through a communication passage 22.
Connect to 23. Further, the trigger valve stem is provided in the hollow parts of the pilot chamber 20 and the pilot valve stem 19.
24 are slidably accommodated. Between the small hole 21 and the pilot chamber 20, a seal ring 25 at the upper center of the trigger valve stem 24 is opened and closed by coming into contact with and separated from the inner wall of the lower end of the pilot valve stem 19, and the communication passage 22 and the pilot chamber 20. Between 20 and 20, the seal ring 26 at the lower center of the trigger valve stem 24 is
It is opened and closed by coming into contact with and separating from the inner wall of the. The trigger valve stem 24 is constantly urged downward by a spring 28, and the lower end thereof is arranged to face the trigger lever 29 and moves up and down by manual operation of the trigger lever 29.

The contact valve 23 is operated by a contact member 31 which is operated in contact with the material 30 to be driven.
As shown in the figure, a valve cylinder 33 disposed in a valve housing 32 and having an upper end closed, an exhaust valve 34 and an intake valve slidably disposed in the valve cylinder 33.
It is composed of 35 and an operation stem 36.

The contact member 31 normally projects from the tip of the nose portion 4 and moves relative to the nose portion 4 when pressed against the driven material 30.

The exhaust valve 34 has a sleeve-like shape having a hollow portion in the center and is formed to have a large diameter. It is configured to open and close the flow path between the exhaust port 39 formed below the valve housing 32 and the communication passage 22 by contacting and separating from the annular seal surface 38 formed on one side. Further, the exhaust valve 34 is constantly urged in a direction of closing the flow path by a spring 41 provided between the exhaust valve 34 and the lower end of the valve cylinder 33.

The intake valve 35 is arranged above the exhaust valve 34, and has an annular wall 42 at the top.
Is formed, a concave portion 43 is formed inside thereof, and the lower portion is narrowed to a small diameter to integrally form a hollow stem 44. The hollow stem 44 penetrates the hollow portion of the exhaust valve 34 and projects downward. When reciprocating in the valve cylinder 33, the intermediate seal ring 45 abuts and separates from the inner wall of the valve cylinder 33 to open and close the flow path between the communication passage 22 and the air chamber a. Is configured.

Next, the operation stem 36 includes the valve cylinder 33 and the intake valve 35.
It is arranged in the delay chamber 46 defined between the upper end of the spring and the upper recess, and is always urged downward by the spring 43. In addition, a valve ring 47 is provided on the upper part of the hollow stem 44 of the intake valve 35.
Is inserted through and protrudes downward. In addition, the intake valve 35
A seal ring 48 is provided between the bottom surface of the concave portion of the operation stem 36 and the valve ring 47 of the operation stem 36, and when the valve ring 47 abuts and separates from the seal ring 48 when reciprocating, the stem 44
The flow path formed between the delay chamber 46 and the exhaust port 39 is opened and closed.

The delay chamber 46 is always in communication with the air chamber a via a communication passage 55 formed in the side wall of the valve cylinder 33 and a minute diameter flow passage 51 formed in the upper annular wall 42 of the intake valve 35. .

The exhaust valve 35 and the springs 41 and 43 of the operation stem 36 are omitted in FIGS. 1 and 4.

In the above-mentioned configuration, before the contact striking operation, as shown in FIG. 1, the exhaust valve 34, the intake valve 35, and the operation stem 36 which form the contact valve 23 are located below, and the communication passage 22 and the exhaust port 39 are connected. 2 is closed, the delay chamber 46 is filled with compressed air, and the flow path between the main chamber and the communication passage 22 is open. Therefore, as shown in FIG. The inside is full. On the other hand, the pilot valve stem 19 is supplied to the pilot chamber 20 through the small hole 21. Therefore, the pilot valve stem 19 is pushed up by the compressed air supplied to the pilot chamber 20 through the contact valve 23 and the small hole 21 to close the exhaust hole 15, and the compressed air is supplied into the main valve control chamber 12. The main valve 10 is biased to the exhaust position by this air pressure. At this time, the striking piston 9 does not move.
Further, the trigger valve stem 24 is located below by the force of the spring 28.

Next, pull the trigger lever 29, as shown in FIG.
As the trigger valve stem 24 is pushed up, the flow path between the pilot chamber 20 and the communication passage 22 opens. But,
Since the communication passage 22 is already filled with compressed air, the air pressure in the pilot chamber 20 does not drop, and the pilot valve stem 19 remains held in the same position as in FIG.

When the contact member 31 is then pressed against the material 30 to be driven, the contact member 31 moves relative to the nose portion 4 as shown in FIG. 4, and the exhaust valve 34 and the intake valve 35 of the contact valve 23 are moved. And the operating stem 36 are moved upward.

By moving the contact member 31 upward, first, the seal between the valve ring 47 of the operating stem 36 and the seal ring 48 is released, the compressed air in the delay chamber 46 is opened to the exhaust port 39, and then the intake valve 35. Is moved to close the flow path between the main chamber and the communication passage 22, and then the exhaust valve 34 is actuated to move the seal ring 37 at the lower end away from the annular seal surface 38, and both seals are released instantaneously. With communication passage 22 and exhaust port
The channel with 39 is opened. Moreover, since the opening area of the exhaust valve 34 is set large, a large amount of compressed air is instantaneously exhausted.

Since the compressed air in the pilot chamber 20 is also exhausted from the communication passage 22, the pilot chamber 20 is depressurized and the pilot valve stem 19 moves downward as shown in FIG.
As a result, the pilot valve stem 19 connects the exhaust hole 15 and the main valve control chamber 12 to move the main valve 10 upward. Compressed air is introduced above the striking piston 9 from the air supply / exhaust port 13, and the striking piston 9 is driven to drive out the nails supplied into the nose portion 4. Since the force due to the reaction acts on the upper wall 7 of the movable striking cylinder 6, the movable striking cylinder 6 moves upward, whereby the reaction due to the driving of the striking piston 9 is canceled. The downward movement of the pilot valve stem 19 causes the seal ring 25 of the trigger valve stem 24 to re-close between the stoma 21 and the pilot chamber 20. As a result, the inflow of compressed air from the small holes 21 into the pilot chamber 20 is stopped.

After the nail driving, when the contact member 31 is separated from the driven material 30, the exhaust valve 34, the intake valve 35, and the operation stem 36 of the contact valve 23 move downward again as shown in FIG. Since the flow passage between the passage 22 and the exhaust port 39 is closed, the flow passage between the air chamber a and the communication passage 22 is opened, and compressed air is supplied into the pilot chamber 20 through the communication passage 22, The pilot valve stem 19 again moves upward to close the exhaust hole 15, and the air chamber a and the main valve control chamber 12
And move to the open position. Therefore, the main valve 10 moves to a position where the air supply / exhaust port 13 is closed, and the compressed air in the movable striking cylinder 6 flows from the air supply / exhaust port 13 to the opening 14 in FIG.
Exhausted through the exhaust hole 11, the striking piston 9 rises and returns by the compressed air stored in the blowback chamber 52 at the time of striking.

By the way, when the contact member 31 is separated from the driven material 30 as described above, the exhaust valve 34 of the contact valve 23 and the operation stem 36 are immediately returned and moved by the springs 41 and 43,
The flow path between the communication passage 22 and the exhaust port 39 is closed, and the delay chamber is closed.
The flow path between 46 and the exhaust port 39 is closed. In contrast, the intake valve 35
The return movement from the position shown in FIG. 4 to the position shown in FIG. 1 is delayed. The reason for this is that in order for the intake valve 35 to return and move, sufficient compressed air must be supplied to the delay chamber 46 and the internal pressure must be sufficiently high. Is done through the delay chamber
This is because the supply of the compressed air into the inside of the delay chamber 46 is delayed, and the pressurization inside the delay chamber 46 is delayed. As a result, the supply of compressed air from the air chamber a to the pilot chamber 20 via the communication passage 22 is delayed, the upward return of the pilot valve stem 19 is delayed, and the main valve control chamber 12 is moved to the air chamber a. The connection operation is delayed.

In this way, the pilot valve 18 does not wait until the pressure in the delay chamber 46 becomes sufficiently high to operate the intake valve 35 after a predetermined time determined by the volume of the delay chamber 46 and the small diameter flow passage 51 has elapsed. Since it operates, the main valve control chamber 12 is opened to the atmosphere during that time, the exhaust is sufficiently performed, and the operation of the main valve 10 is completely performed. Since the pilot chamber 20 and the small hole 21 are closed by the seal ring 25 of the trigger valve stem 24 as described above, compressed air does not flow into the pilot chamber 20 through the small hole 21. Therefore, the delay is determined by the capacity of the delay chamber 46 and the flow path 51 having a small diameter.

Therefore, even when the contact valve 23 is kept in an operating state for an extremely short time such as when the contact member 31 is pressed against the driven material 30 and then immediately separated from each other, the pilot valve stem 19 Can be delayed and returned, so that the main valve 10 can be fully operated.

The striking cylinder does not have to be movable.

[Brief description of drawings]

1 to 4 are explanatory views of an operation mode of a safety device of a compressed air type nailer according to the present invention, FIG. 5 is a longitudinal sectional view of the nailer, and FIG. 6 is a contact valve and a contact member. FIG. Reference numeral a ... Air chamber, 1 ... Housing, 4 ... Nose portion, 6 ... Movable impact cylinder, 9 ... Impact piston, 10 ... Main valve, 18 ... Pilot valve, 19 ... Pilot valve stem, 20 ... Pilot chamber, 22 ... Station Aisle, 23
... Contact valve, 24 ... Trigger valve stem, 31 ... Contact member, 32 ... Valve housing, 34 ... Exhaust valve, 35
... intake valve, 36 ... operation stem, 39 ... exhaust port, 46 ... delay chamber, 51 ... small diameter flow path

Claims (1)

[Scope of utility model registration request] 1. A striking cylinder disposed in a housing,
A striking piston integrally provided with a nail driving driver slidably disposed in the cylinder, an air chamber constantly connected to a compressed air supply source, and an air chamber above the striking piston of the striking cylinder. A nailing machine comprising a main valve selectively connected to the atmosphere, comprising a pilot valve stem for selectively connecting a main valve control chamber controlling the operation of the main valve to the air chamber and the atmosphere, and the pilot A pilot valve that is operated by supplying and discharging compressed air to and from a pilot chamber that accommodates one end of a valve stem, and a communication passage that is operated by a contact member that is operated in contact with a material to be driven and that communicates with the pilot chamber. A contact valve that selectively connects the exhaust port and the air chamber, and a manually operated trigger lever And a trigger valve stem that opens and closes a communication passage that communicates between the pilot chamber and a contact valve, the contact valve being disposed in a valve housing and having a closed top end. A sleeve-shaped exhaust valve that is arranged in the valve cylinder and that opens and closes a flow path between the exhaust port formed in the valve housing and the communication passage, and a hollow portion of the exhaust valve that penetrates and projects downward. Has an integrated hollow stem and is arranged above the exhaust valve in the valve cylinder, and opens and closes a flow path between the communication passage and the air chamber; and a hollow stem of the intake valve. Is inserted and protrudes downward, and is disposed in a delay chamber defined between the valve cylinder and the upper end of the intake valve, and is disposed above the delay chamber. A compressed air nailing device, characterized in that it is configured by an operation stem that opens and closes a flow path with an exhaust port, and that the delay chamber is always in communication with the air chamber through a flow path having a minute diameter. Machine safety device.