JPS6222754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a contact prevention device for a fastener setting machine, and more specifically, to a contact arm prevention device for a fastener setting machine. In cooperation with the operation,
For the first time, the nailing machine can be kept in a ready state for operation, and if the trigger valve is activated first, the safety valve will automatically operate and disable the above cooperation, leaving the nailing machine in an inoperable state. This invention relates to a contact drive prevention device for a fastener setting machine.

Generally, a fastener driving machine sequentially supplies a series of rivets to an injection port, and drives a driving driver facing the injection port using high air pressure to drive the rivets into the workpiece, such as concrete or steel plate. A fastener driving machine that drives rivets into hard materials uses extremely high-pressure air as a driving source. However, when driving with such high air pressure, it is necessary to make sure that the tip of the injection port hits the surface of the workpiece perpendicularly before firing the rivet. If the rivet is fired diagonally toward the workpiece, since the workpiece is hard, it may hit the surface of the workpiece and bounce in an unexpected direction, potentially causing an unexpected accident. For this reason, so-called contact driving, in which the trigger lever is pulled in advance and the contact arm provided at the tip of the injection port is pressed against the workpiece to fire the rivet, must be avoided. This is because in this type of contact driving, the moment the contact arm is pressed against the surface of the workpiece, the rivet driving machine is activated and the rivets are fired, and the rivets are fired perpendicular to the surface of the workpiece. This is because there is no time to check and adjust the direction of the injection port. Similarly, there is also so-called dribbling, in which the tip of the contact arm hits the surface of the workpiece against the operator's intention due to the recoil when the nailing machine operates, resulting in the driving of the nailing machine. must be strictly avoided.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks and to propose a contact driving prevention device which is particularly capable of preventing contact driving in a fastener driving machine driven by high-pressure air.

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

In the figure, the symbol A is a nailing machine, and this nailing machine A
Loads the rivets 3 into the injection port 2 using a tack feeding device (not shown), presses the tip pressing portion of the contact arm 4 protruding from the tip of the injection port 2 against the workpiece 5, and pulls the trigger lever 6. By operating the trigger valve 7 and exhausting the air in the head valve upper chamber 10 from the trigger valve 7, the head valve 9, which is in the closed state, is opened and the high pressure air stored in the main chamber 8 is released into the main cylinder 11.
, the driving piston 12 fitted in the cylinder 11 is instantly advanced, and the piston 12 is
The rivet 3 is driven into the workpiece 5 by a driver 13 provided in the workpiece 5. The main chamber 8 is connected directly to an external driving air source (not shown) or to a booster (not shown) built into the nailing machine A.
The trigger valve 7 connects the high pressure air in the main chamber 8 from the air introduction chamber 14 to the control chamber, as shown in FIGS. 15, the air is supplied to the head valve upper chamber 10, etc., and by pulling the trigger lever 6, the supplied air is exhausted from the control chamber 15 to the outside, and by releasing the trigger lever 6, the air is discharged again. When the trigger valve stem 16, which supplies air and protrudes to the outside, is pushed inside, an exhaust gap is created on the outside of the stem 16, and the air that was biasing the cylindrical valve 17 is exhausted and the cylindrical valve 17 is moved upward, thereby creating an exhaust gap between the valve 17 and the trigger valve housing 18, and the air inside the control chamber 15 is exhausted together with the supply air supplied to the head valve upper chamber 10 and the like. At the same time, communication between the air introduction chamber 14 and the control chamber 15 is cut off. Trigger lever 6
When released, the spring pressure will cause the trigger valve stem 16 to
protrudes outside and stops exhausting, so the cylindrical valve 17 is biased to its original position and the air introduction chamber 14 is
The control room 15 communicates with the control room 15, and air is supplied from the control room 15 again. Therefore, the above-mentioned supply air is control air whose supply and exhaust can be controlled by operating the trigger valve 7.

As described above, the operation of the head valve 9 is performed in conjunction with the operation of the trigger valve 7, but for safety reasons, the head valve upper chamber 10 is normally placed in direct communication with the main chamber and is placed outside the control of the trigger valve 7. Only when the valve control chamber 15 is communicated is the setting machine ready for operation. That is, when the head valve upper chamber 10 communicates with the main chamber 8, even if the trigger valve 7 is operated, the control air is not connected to the head valve upper chamber 10, so the head valve 9 will not operate. The head valve 9 can be operated in conjunction with the operation of the trigger valve 7 only when the head valve upper chamber 10 and the trigger valve control chamber 15 are in communication. Switching of the connection between the head valve 9 and the main chamber 8 or the trigger valve 7 is controlled by the pilot valve 20.

The pilot valve 20 has a valve sleeve 22
The inner part moves up and down as shown in the figure, and selectively communicates the air passage leading to the head valve 9 with the air passage leading to the main chamber 8 or the air passage leading to the trigger valve 7, thereby controlling the opening and closing of the head valve 9 of the nailing machine A. The operation is briefly explained as follows. That is, the pilot valve 20
is normally at the top dead center position in FIGS. 4a and 4b, and since the head valve upper chamber 10 is directly connected to the main chamber 8 at this time, the head valve 9 will not operate even if the trigger valve is actuated.
On the other hand, when the valve stem 24 is pushed up, the seal between the stem 24 and the valve cap 21 is released, and the air in the pilot valve lower chamber 30 is discharged from around the valve stem 24 to below the valve cap 21. The pilot valve 20 loses support from the air pressure and moves downward to bottom dead center. With the above-mentioned lowering, the air passage leading to the head valve 9 is cut off from the air passage leading to the main chamber 8 and communicated with the air passage leading to the trigger valve 7. The fastening machine is now ready for operation. Therefore, when the trigger lever 6 is pulled, the high-pressure air in the head valve upper chamber 10 is discharged from the trigger valve 7, and the high-pressure air in the main chamber 8 is supplied into the driving cylinder 11.
3 is driven. In addition, by pulling the trigger lever 6, the air above the pilot valve 20 is exhausted, and accordingly, the pilot valve 20
The air in the lower chamber 30 is also discharged through the gap 25 formed through the center;
Since air is difficult to be discharged from the upper end throttle hole 26, the pilot valve 20 automatically rises again due to the residual pressure in the cavity 25 and the spring pressure, and reaches the top dead center. When the trigger lever 6 is released, the high pressure air from the main chamber 8 is supplied to the lower chamber 30 via the trigger valve 7 and through the cavity 25 of the pilot valve 20, so the pilot valve 20 remains at the top dead center. Retained.

As mentioned above, the switching operation in which the pilot valve at the top dead center moves downward to switch the air connection circuit is performed when the tip of the contact arm 4, which is installed near the injection port of the fastener setting machine, moves down to the lower part of the pilot valve 20. This occurs when the valve stem 24 is pushed in, at which time the fastener A is held in a ready state. The reason why the contact arm 4 pushes up the valve stem 24 is to push the contact arm 4 up against the workpiece 5.
Contact operation and safety valve 4
This is when the supply of output air from 0 cooperates.

Next, the contact arm 4 and the safety valve 40 will be explained in detail with reference to FIGS. 4a and 4b.

The contact arm 4 is provided near the injection port 2 of the fastening machine A, and is activated by a contact operation in which one end 33 is pressed onto the workpiece 5, and the other end 35 presses the valve stem 24. A first arm 31 whose lower end 33 is pressed against the surface of the workpiece 5 in FIG. The second arm 32 is connected by fitting the lower end 36 into the provided expansion cylinder 37, and the lower end opening 38 of the cylinder 37 communicates with a safety valve 40, which will be described later. When output air is supplied from the valve 40 into the expansion cylinder 37, the cylinder 37 is expanded by the air pressure of the air, the second arm 32 is pushed up, and the contact arm 4 is expanded as a whole. In this state, when a contact operation is further performed to press the lower end 33 of the first arm 31 against the workpiece 5 and the contact arm 4 moves upward, the tip 35 of the second arm 32 is brought into contact with the lower part of the pilot valve 20. The valve stem 24 is pushed up and operated, and the pilot valve 20 is switched and operated. Therefore, the operation of the valve stem 24 is performed by the cooperation of the air supply from the safety valve 40 and the contact operation. On the other hand, when the trigger valve 7 is activated and the control air is exhausted from the control chamber 15, the air is also exhausted from the expansion cylinder 37, so the cylinder 3
7 is contracted, and the second arm 32 is compressed by the action of the spring pressure.
moves downward, and the contact arm 4 becomes shorter as a whole. Therefore, the valve stem 24 cannot be pushed up only by contact operation.

Note that the expansion cylinder 37 is not limited to the example provided at the intermediate portion of the contact arm 4 as described above.

Next, the safety valve 40 has an annular recess 41 in the forehead (on the left side when facing the drawing) and an enlarged part 42 in the middle part, and has a front chamber 43a.
The valve housing 43 is fitted in a cylindrical valve housing 43 having an inner diameter smaller than the inner diameter of the rear chamber 43b and communicating with the trigger valve and the contact arm 4 so as to be able to reciprocate between a first position at the front and a second position at the rear. ing. Small diameter front chamber 4 of the valve housing 43
3a has an air passage 46 communicating with the trigger valve 7.
is opened, and an air passage 47 communicating with the cylinder 37 of the contact arm 4 is opened in the large diameter rear chamber 43b. Further, the annular recess 41 at the front of the safety valve 40 fits into the small-diameter front chamber 43a of the valve housing 43 to form a cavity 44, whereas the enlarged portion 42 fits into the large-diameter rear chamber 43b. It matches. A coil spring 45 is interposed between the enlarged portion 42 and the rear end portion of the valve housing 43.

When the safety valve 40 is in the first position as shown in FIG. 4a, the safety valve 40 is
The air pressure is supplied to the cavity 44 and acts on the front and rear end surfaces of the annular recess 41, but the air pressure acting on both end surfaces is the same. Therefore, the safety valve 40 is normally biased to the first position by the spring bias of the coil spring 45. At this time, since the front air passage 46 and the rear air passage 47 are cut off, output air cannot be supplied from the safety valve 40 to the expansion cylinder 37 of the contact arm 4. On the other hand, safety valve 40
When the valve housing 43 is moved back to the second position, as shown in FIG. Rear chamber 43
b is connected to the space 44 of the safety valve 40 that has moved rearward with the above-mentioned backward movement, and the front and rear air passages 46 and 47 are connected through this connection space 48, and are in contact with the trigger valve 7. It communicates with the expansion cylinder 37 of the arm 4. At this time, due to the high pressure air supplied from the front air passage, air pressure acts in opposite directions on the front end surface (front end surface of the concave portion 41) and rear end surface (front end surface of the enlarged portion 42) of the connection space 48. do. In this case, the backward working pressure of the air pressure acting on the front end surface of the connection space 48 is greater than the forward working pressure obtained by adding the spring pressure of the coil spring 45 to the air pressure acting on the front end surface of the connection space 48. It is set to be large. This allows the second
The safety valve 40 that has retreated to the position is self-maintained at that position. Furthermore, as described above, when retracting from the first position to the second position, the front and rear air passages 4
6 and 47 are in communication, so the safety valve 40
output air is supplied into the expansion cylinder 37 of the contact arm 4, which expands to extend the second arm 32. Furthermore, the output air from the safety valve 40 and the contact arm 4
The pilot valve 20 can be actuated for the first time in cooperation with the pressing operation on the workpiece 5, and the air in the air passages 46, 47 is released from the trigger valve 7 in synchronization with the firing operation of the fastener A. When the air is exhausted, the air inside the safety valve 40 and the expansion cylinder 37 is also exhausted, and the air pressure is also released accordingly, so the safety valve 40 loses its self-holding force and the spring tension of the coil spring 45 is released. Due to the force, it moves forward again to the first position and is biased there. Furthermore, the expansion cylinder 37 also contracts as the output air from the safety valve 40 is exhausted, and therefore the contact arm 4 shortens.

Therefore, next, the air flow in the nailing machine A is mainly controlled by the expansion cylinder 37 of the contact arm 4.
This will be explained in relation to the operation of the safety valve 40.

First, before driving the nail driving machine, high pressure air in the main chamber 8 is supplied to the head valve 9 via the pilot valve 20, while the trigger valve 7
It is supplied to the pilot valve 20 located at the top dead center through the air, and is also supplied to the safety valve 40. In driving the above-mentioned nailing machine A,
First, the safety valve 40 is moved from the first position to the second position in connection with manual operation or operation of the tack feeding device.
retreat into position. At this time, the safety valve 40 and the expansion cylinder 37 of the contact arm 4 communicate with each other, and the output air from the safety valve 40 is supplied to the cylinder 37.
expands, thereby causing the second contact arm 4 to
Arm 32 extends.

At this stage, even if the trigger lever 6 is pulled, the fastener A is not driven. Because trigger lever 6
When pulled, air is exhausted from the trigger valve 7, but the pilot valve 20 is not activated thereby. This is because the air supplied to the head valve 9 does not change. Furthermore, the air supplied to the expansion cylinder 37 of the contact arm 4 via the safety valve 40 is also exhausted at the same time, and the self-holding of the safety valve 40 is released, and the expansion cylinder 37 contracts, so that the contact arm 4 is shortened back to its original state, and the fastener A is kept in a state where it cannot be operated.

Retract the safety valve 40 to the second position,
After expanding the cylinder 37 of the contact arm 4 by the output air, when the base of the first arm 31 of the contact arm 4 is pressed against the workpiece 5, the second arm 37 is expanded by the cooperation of the air and the contact operation. The tip of the arm 32 pushes up the valve stem 24 and moves the pilot valve 20 down. By operating the pilot valve 20, communication between the main chamber 8 and the head valve upper chamber 10 is cut off.
Communication is established between the trigger valve 7 and the head valve upper chamber 10, and the fastener setting machine A becomes ready for operation.
When the trigger lever 6 is pulled in this state, the air is exhausted from the trigger valve 7 and at the same time the air in the head valve upper chamber 10 is also exhausted, so the head valve 9 is activated and high pressure air is discharged from the main chamber 8 into the main cylinder 11. and the driver 13
instantly descends and fires the rivet towards the material to be driven. Then, in synchronization with the exhaust from the trigger valve 7, the trigger valve 7 is connected to the expansion cylinder 3 of the contact arm 4 via the safety valve 40.
The air that was supplied to the inside of the safety valve 4
0 self-holding is released and the valve 40 is moved forward to the first position to be evacuated, so the contact arm 4 is shortened and the fastener A cannot be fired, maintaining a safe state. After that, by releasing the trigger lever 6, the main chamber 8
Internal air is supplied to the pilot valve 20 and safety valve 40 via the trigger valve 7.

As mentioned above, in order to switch and operate the pilot valve 20 that controls the opening and closing of the head valve 9 by the firing operation of the nail setting machine A, in addition to the contact operation of the contact arm 4, the cylinder 37 of the contact arm 4 must be activated. Safety valve 4 inside
It is necessary that output air from 0 is supplied and the two cooperate, and furthermore, in order to supply air into the cylinder 37, the safety valve 40 must move from the first position to the second position. is necessary. However, since the output air is supplied from the safety valve 40 when the trigger valve 7 is in the non-operating state, the contact operation is effectively performed only when the trigger valve 7 is in the non-operating state. Therefore, when the trigger valve 7 is actuated first, the self-holding of the safety valve 40 in the second position is released and the safety valve 40 advances to the first position.
At the same time, the air inside the expansion cylinder 37 is released from the trigger valve 7.
Since the air is exhausted from the control chamber 15, the cylinder 37 is contracted, so even if a contact operation is performed after that, the operation will not work with the air, so the above operation will become invalid. Contact strikes are prevented.

Therefore, when using the fastener A, it is impossible to fire the fasteners 3 unless you first firmly press the tip 33 of the contact arm 4 against the workpiece 5 and then perform the firing operation. Can not. Even if the firing operation is performed before the contact operation, the stud 3 will not be fired, so contact driving will not be possible. Moreover, after firing a rivet, the self-holding of the safety valve 40 is released and moves to the first position where the rivet driving machine A cannot operate, so that the rivet driving machine A is in a safe state. Therefore, even if the tip of the contact arm 4 continuously touches the workpiece 5 due to the reaction when driving the nailing machine A.
Even if this results in pressing, the next rivet firing will be invalid. Therefore, dribbling is also prevented.

As explained in detail above, the contact drive prevention device of the fastener setting machine of the present invention includes a trigger valve having a control chamber for controlling the opening and closing of air supply and exhaust introduced from the main chamber, and a trigger valve from the tip of the injection port of the fastener setting machine. an expansion cylinder provided on a portion of the protruding contact arm and expanded by air supply, which cooperates with the pressing operation of the contact arm to maintain the fastener driver in a state of readiness for operation, and communicates with the trigger valve control chamber; On the other hand, it is connected to the expansion cylinder and is provided so as to be able to reciprocate between a first position where it is biased by a spring and a second position where it is operated by tack feeding, manual operation, etc., and in the second position, the trigger is activated. It is self-held by the air pressure of the air supplied from the valve control chamber, and the air is supplied to the expansion cylinder, and when the trigger valve is operated, the self-holding is released by exhaust from the trigger valve control chamber, and it moves from the second position to the second position. The present invention is characterized by comprising a safety valve that operates to the first position and cuts off air supply to the expansion cylinder. Therefore,
In order to operate the nailing machine, the safety valve must move from the first position to the second position when the contact operation of the contact arm and the air supply into the cylinder of the contact arm cooperate. It is. However, if the trigger valve is activated at this time, the air inside the expansion cylinder will be exhausted.
As a result, the self-holding of the safety valve is released and the safety valve is operated to the first position, so the above-mentioned cooperation is not established, and therefore, even if a contact operation is performed, it becomes invalid. In order for the above cooperation to take place, the safety valve must be operated to the second position again. Therefore, contact damage can be reliably prevented. Furthermore, when the trigger valve is actuated to drive the fastener, the self-retention of the safety valve is released, and the air inside the expansion cylinder is also exhausted, eliminating the risk of dribbling and turning the safety valve back into the second position. The fastener is held in a non-operational safe state until activated into position.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a fastener A equipped with a contact prevention device according to the present invention, FIG. 2 is a summary explanatory diagram of the air communication state of the fastener, and FIGS. 3 a and b are trigger valves. It is an explanatory diagram of the operating state of the fourth
Figures a and b are explanatory views of the operating states of the pilot valve, safety valve and contact arm. Code A...tacker, 2...injection port, 3...tack,
4... Contact arm, 5... Workpiece, 7...
...Trigger valve, 10...Head valve upper chamber, 1
5... Control room, 24... Valve stem, 31...
First arm, 32... Second arm, 37... Expansion cylinder, 38... Opening, 40... Safety valve, 41... Annular recess, 42... Ampulla, 4
3...Valve housing, 45...Coil spring,
46, 47...Air passage, 48...Empty space.

Claims (1)

[Claims] 1. A trigger valve that has a control chamber that controls the opening and closing of the air supply and exhaust introduced from the main chamber, and a trigger valve that is provided on a part of the contact arm that protrudes from the tip of the injection port of the fastener driver and that expands when air is supplied, an expansion cylinder that cooperates with the pressing operation of the arm to maintain the nailing machine in a state of readiness for operation; and an expansion cylinder that communicates with the trigger valve control chamber;
A first spring-biased cylinder communicating with the expansion cylinder.
It is provided so as to be able to reciprocate between the position and a second position operated by tack feeding, manual operation, etc. from the position,
In the second position, the trigger valve is self-held by the air pressure of the air supplied from the trigger valve control chamber, and the air is supplied to the expansion cylinder, and when the trigger valve is activated, the self-holding is released by exhaust from the trigger valve control chamber. 1. A contact driving prevention device for a nail setting machine, comprising: a safety valve that operates from a second position to a first position and shuts off air supply to the expansion cylinder.