JPS6222753B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a safety device for a fastener setting machine.

In general, a fastener driving machine sequentially supplies a series of rivets to an injection port, and drives a driving driver facing the injection port with high-pressure air to drive the rivets into a workpiece, such as concrete or steel plate. Fastener driving machines that drive rivets into hard materials use extremely high-pressure air as a driving source, so accurate and safe operation is required when firing the rivets. Therefore, contact driving, in which the trigger lever is pulled in advance and the tip of the injection port of the fastener is pressed against the surface of the workpiece to fire the rivets, or the tip of the injection port may be fired continuously due to the recoil during firing. When a fastener driver is driven by the so-called dribble that is ejected as a result of hitting the workpiece, it is difficult to accurately orient the ejection port perpendicularly to the surface of the workpiece, and it tends to be oriented diagonally. In this case, the studs may bounce off the surface of the workpiece, causing an unexpected accident, and must be avoided.

The present invention was developed in view of the above circumstances, and an object of the present invention is to propose a safety device for a fastener setting machine that can reliably prevent contact driving and dribbling, and ensure safe operation of the fastener setting machine at all times. do.

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

In Figures 1 to 3, symbol A is a riveting machine;
This rivet driving machine A loads rivets 3 into an injection port 2 using a tack feeding device (not shown), presses the tip pressing portion of a contact arm 4 protruding from the tip of the injection port 2 against a workpiece 5, By pulling the trigger lever 6, the trigger valve 7 is actuated and the air in the upper chamber 10 of the head valve is exhausted from the trigger valve 7, thereby opening the head valve 9 which is in the closed state and releasing the high pressure air stored in the main chamber 8 to the main chamber. is supplied to the cylinder 11, and the driving piston 12 fitted in the cylinder 11 is instantly advanced;
The stud 3 is driven into the workpiece 5 by a driver 13 provided on the piston 12. The main chamber 8 communicates directly with an external driving air source (not shown) or indirectly through a booster (not shown) built into the fastening machine A, and introduces high-pressure air into the interior. The trigger valve 7 introduces the high pressure air in the main chamber 8 from the air introduction chamber 14 into the control chamber 15, as shown in FIGS.
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 supplied again, so the trigger valve protrudes to the outside. When the stem 16 is pushed in, 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 actuates the cylindrical valve 17, which causes the valve 17 and the trigger to An exhaust gap is created between the control chamber 15 and the 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. When the trigger lever 6 is released, the spring pressure causes the trigger valve stem 16 to protrude outside and stop the exhaust, so the cylindrical valve 17 is biased to its original position and the air introduction chamber 14 and control chamber 15 are communicated with each other. , 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.

In this way, the operation of the head valve 9 is performed in conjunction with the operation of the trigger valve 7, but the upper chamber 10 of the head valve can be selectively connected to either the main chamber 8 or the trigger valve 7 via the one-cycle valve 20. It is something that communicates with
When the fastener setting machine is not in operation, it communicates with the main chamber 8. In this way, when the head valve upper chamber 10 communicates with the main chamber 8, even if the trigger valve 7 is operated, its control air is not connected to the head valve 9, so the head valve 9
doesn't work. 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. And head valve 9
Control of switching the connection between the main chamber 8 or the trigger valve 7 is performed by the one-cycle valve 20.

That is, as shown in FIGS. 4a and 4b, the one-cycle valve 20 communicates with the control chamber 15 of the trigger valve 7 at its upper end, communicates with the head valve upper chamber 10 and the main chamber 8 at its upper end, and further communicates with the control chamber 15 of the trigger valve 7 at its upper end. Inside the valve housing 22 with the valve cap 21,
A sleeve-shaped valve 23 is fitted so as to be able to reciprocate up and down, and a valve stem 2 is opposed to the valve 23 and protrudes below the valve cap 21.
4 is provided, and by supplying and discharging control air from the trigger valve 7 and operating the valve stem 24, the valve 23 is moved to the non-operating position (top dead center) where the main chamber 8 and the head valve upper chamber 10 communicate with each other, or to the upper head valve position. The trigger valve control chamber 10 and the trigger valve control chamber 15 communicate with each other by switching to one of the operation ready positions (bottom dead center), and when the trigger valve is in the operation ready position, the firing operation of the nailing machine A automatically causes the trigger valve to be activated. The switching operation causes the driving piston 12 to move forward,
This allows one cycle of backward movement.

The valve 23 is sleeve-shaped, and a throttle hole 26 is formed at the end of the inner cavity 25 on the trigger valve 7 side, and annular protrusions 27, 27 are formed on the outer surface to seal against the inner surface of the valve housing 22. A communication space 28 is formed. And valve 2
3 is at the top dead center position, the above communication space 28
When the main chamber 8 is at the bottom dead center, the trigger valve control chamber 15 and the head valve upper chamber 10 are communicated with each other. Further, a coil spring 29 is interposed between the valve 23 and the valve stem 24, and the valve 23
is biased upward. The spring pressure of the coil spring 29 is set smaller than the air pressure of the control air acting on the upper end surface of the valve 23. The valve stem 24 is formed to be insertable into the cavity 25 of the valve, and is normally in a sealed state with the valve cap 21, but is shallowly inserted into the lower end opening of the cavity 25 to prevent air from being discharged from the opening. However, when it is pushed into the valve housing 22, it releases the seal with the valve cap 21 to create an exhaust gap, and is deeply inserted into the cavity 25 to seal its lower end opening.

The one-cycle valve 20 is configured such that when the fastener A is in an inoperative state, the control air supplied from the trigger valve 7 is supplied to the valve 23 as shown in FIG. 4a.
This air pressure acts on the upper and lower end surfaces of the valve 23 because the air is supplied to the lower valve chamber 30 through the gap 25 . At this time, the effective pressure receiving area of the upper and lower end surfaces is
Since the lower end surface is set larger than the upper end surface, the valve 23 is biased toward the top dead center. The communication cavity 28 therefore provides direct communication between the main chamber 8 and the head valve upper chamber 10. At this point, even if the trigger valve 7 is activated by the firing operation of the fastener A and the control air is exhausted to the outside, the air is simply exhausted from the gap 25 of the valve 23 and the lower chamber 30. Since the valve 23 is still held at the top dead center by the spring bias, the state of communication between the head valve upper chamber 10 and the main chamber 8 is also maintained, and therefore the fastener A is kept in a state in which operation is impossible. ing. On the other hand, the figure b
When the valve stem 24 is pushed into the valve housing, the air in the lower chamber 30 of the valve 23 is exhausted from the valve cap 21, so that the valve 23 loses air support and moves downward. At that time, the valve stem 24 is inserted into the cavity 25 of the valve 23.
Since it is deeply inserted into the cavity, the lower end opening of the cavity 25 is sealed, and the air inside the cavity 25 is retained as it is. When the valve 23 moves downward, the communication space 28 also moves downward, so that communication between the main chamber 8 and the head valve upper chamber 10 is cut off, and instead, the head valve upper chamber 10 and the trigger valve control chamber 15 are communicated with each other. However, only at this time does the fastener A become ready for operation. When the firing operation is performed with the communication switched, and the trigger valve 7 is activated as shown in FIG. It opens and the driving piston 12 is driven forward. Similarly, the air in the cavity 25 of the valve 23 is also exhausted from the trigger valve 7, but at that time, the air has to pass through the throttle hole 26, so it takes time to exhaust from the cavity 25. The air above the valve 23 is exhausted before the air inside the gap 25 is exhausted. For this reason,
While the air pressure acting on the upper end surface of the valve 23 is released, the residual pressure air and the spring pressure in the cavity 25 act upward, so due to this pressure difference, a predetermined time delay, i.e. After the air in the head valve upper chamber 10 is exhausted from the trigger valve control chamber 15, the valve 23 automatically moves upward and returns to the state shown in FIG. As a result, the head valve upper chamber 10 and the main chamber 8 are communicated again, so that air is supplied from the main chamber 8 to the exhausted upper chamber 10, which closes the head valve 9.
The driving piston 12 moves back and automatically ends the one-cycle operation, and at the same time, the fastener A returns to its inoperable state.

Therefore, the operation of the head valve 9 can be controlled by pulling the trigger lever 6, that is, by operating the trigger valve 7.
This occurs when the one-cycle valve 20 at the top dead center moves downward to switch the air connection circuit, but this switching action also occurs when the valve stem 24 is pushed into the valve housing and activated, that is, when the contact arm The tip of 4 is the valve stem 2 above.
This is done when you press 4.

The contact arm 4 is provided near the injection port 2 of the fastener 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, as shown in FIG. A first arm 31 whose lower end 33 is pressed against the surface of the workpiece 5 and a second arm 32 whose upper end 35 faces below the valve stem 24 are provided at the upper end 34 of the first arm 31. The lower end portion 36 of the second arm 32 is fitted into the expanded cylinder 37, and the lower end opening 38 of the cylinder 37 communicates with the control chamber 15 of the trigger valve 7. When control air is supplied from the valve 7 into the expansion cylinder 37, the cylinder 37 expands due to the air pressure of the air, as shown in FIG. 4a.
The second arm 32 is pushed up as shown by the dotted line, and the contact arm 4 is extended as a whole. In this state, when a contact operation is 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 moved upward for the first time as shown in FIG. 4b. pushes up the valve stem 24 at the bottom of the one-cycle valve 20 to operate it, and the one-cycle valve 20 is switched and operated. Therefore, the valve stem 24 is actuated by the air supply from the trigger valve 7 and the contact operation. In response, the trigger valve 7 is activated and the control air is supplied to the control room 1.
5, the air is also exhausted from the expansion cylinder 37, so the cylinder 37 contracts, the second arm 32 moves downward under the action of the spring pressure, and the contact arm 4 becomes shorter as a whole. The above valve stem 2 can be removed only by contact operation.
You can't push 4 up.

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. Further, what slides inside the cylinder 37 is not limited to the second arm 32, but may be any actuating member that extends the valve stem 24 into an actuable state by air supplied to the cylinder 37. The second arm may be moved up and down by sliding of the actuating member, and the valve stem 24 may be extended to an operable state.

As mentioned above, the firing operation of the fastener setting machine A, that is, the operation of the head valve 9 can be controlled by operating the trigger valve 7, when the valve 23 of the one-cycle valve 20 at the top dead center is activated. This is when the air connection circuit is switched by moving downward, but this switching operation occurs when the injection port 2 of the fastener A
Tip 35 of contact arm 4 provided nearby
is performed when the lower valve stem 24 of the one-cycle valve 20 is pushed in, and the contact arm 4 further pushes up the valve stem 24 as follows.
This is when the contact operation and the supply of control air from the trigger valve 7 cooperate.

In other words, since the control air from the trigger valve 7 is supplied when the trigger valve 7 is in the non-operating state, the contact operation is effective only when the trigger valve 7 is in the non-operating state. If the trigger valve 7 is operated first, the air inside the expansion cylinder 37 will be exhausted from the trigger valve control chamber 15, so the cylinder 37 will be contracted and even if the contact operation is performed,
Since cooperation with air is not established, the above operation becomes invalid.

Therefore, when using the nailing machine A, the tip 33 of the contact arm 4 must be firmly pressed against the workpiece 5, and then the firing operation of pulling the trigger lever 6 must be performed. cannot be fired. Even if the firing operation is performed before the contact operation, the stud 3 will not be fired. For this reason, contact driving is not possible, and if the trigger lever 6 is kept pulled even after a rivet is fired, the next rivet firing will be disabled. Even if the work piece 5 is continuously pressed against the workpiece 5, dribbling is prevented, so it is safe.

In addition, the one-cycle valve 20 is operated by discharging air from the trigger valve 7 based on the firing operation.
Since the head valve upper chamber 10 is automatically brought into direct communication with the main chamber 8 and the head valve upper chamber 10 is rendered uncontrollable, firing due to erroneous operation or accidental explosion can be prevented. Furthermore, if the trigger lever 6 is kept pulled after the stud is fired, the contact operation will be invalidated, but even if, for example, some force is applied and the tip 35 of the contact arm 4 operates the valve stem 24. ,
Valve housing 22 of one-cycle valve 20
Since the inside is evacuated and the pressure is equal to atmospheric pressure,
The valve 23 remains stationary and the one-cycle valve 20 does not switch the air circuit. It is therefore doubly safe.

Next, the manner in which the nailing machine A having the above configuration is used will be explained.

First, before driving the fastener A, the valve 23 of the one-cycle valve 20 is at the top dead center, and the gap 25
and a trigger valve control chamber 15 in the valve lower chamber 30.
Control air is supplied from the main chamber 8, and air to the head valve upper chamber 10 is supplied directly from the main chamber 8. On the other hand, the trigger valve control chamber 1 is also connected to the expansion cylinder 37 of the contact arm 4.
Air is supplied from 5, and the cylinder 37 is expanded. Next, in order to drive the fastener A, the contact arm 4 is first pressed against the workpiece 5, and in cooperation with the air supply to the cylinder 37, the tip of the second arm 32 is pressed against the valve stem. 24
is pushed up, the one-cycle valve 20 is operated to switch the air passage, the head valve upper chamber 10 and the trigger valve control chamber 15 are communicated with each other, and the fastener A is maintained in a ready state for operation. When the trigger lever 6 is pulled in this state, the air in the head valve upper chamber 10 is discharged from the trigger valve control chamber 15, the head valve 9 opens as described above, and the driving piston 1
2 can be driven to drive the studs 3 supplied into the injection port 2 toward the workpiece 5. Note that if the firing operation is performed before the contact operation, the control air will be exhausted from the trigger valve control chamber 15, making the contact operation invalid. Further, along with the firing operation, the air inside the gap 25 of the one-cycle valve 20 is also exhausted, and the one-cycle valve 20 is also exhausted.
0 automatically rises after a predetermined time delay, the head valve upper chamber 10 again communicates directly with the main chamber 8, and the driving piston 12 is retracted and held at the top dead center, so that the fastener A is inoperable. maintained in a possible state. By releasing the trigger lever 6, the one-cycle valve 2 is released from the trigger valve control chamber 15.
High-pressure air is supplied to the gap 25 and its lower chamber 30, and the state before the driving of the fastener A is restored.

As described in detail above, the safety device for a fastener setting machine according to the present invention includes a contact arm that protrudes from the tip of the injection port of the fastening machine and has a pressing portion against the workpiece surface, and one end of which communicates with the trigger valve control chamber. The other end faces the valve stem operated by the contact arm, and further includes a cavity opening at both ends and having a throttle hole formed on the trigger valve side, and is biased by a spring toward the trigger valve side to control the trigger valve. When air is supplied from the chamber, the head valve is in a position to communicate with the main chamber by air pressure and spring pressure acting on both ends of the valve, and when the valve stem is operated,
The trigger valve is moved to a position where the air is retained in the cavity and communicates with the upper chamber of the head valve, and when the trigger valve is operated, after a predetermined time delay as air is exhausted from the trigger valve control chamber,
a one-cycle valve having a sleeve-shaped valve that automatically moves back due to residual air pressure in the cavity and spring bias; and a one-cycle valve that is provided in a part of the contact arm and expands by air supplied from a trigger valve control chamber; The valve stem includes an expansion cylinder that extends the tip of the contact arm so that the valve stem can be operated. For this reason, when the fastener is inactive, the upper chamber of the head valve, which directly controls the drive of the fastener, is connected to the main chamber, so even if the firing operation is performed, the air in the upper chamber of the head valve is not controlled. Therefore, the operation of the nailing machine is maintained in an impossible state and is safe. Next, to prepare the nailer for operation, the tip of the contact arm operates the lower valve stem of the one-cycle valve, causing the one-cycle valve to communicate with the upper chamber of the head valve and the trigger valve control chamber. However, the contact arm can actuate the valve stem by pressing the pressing part when the trigger valve is in the inoperative state and air is supplied from the trigger valve into the expansion cylinder. If the trigger valve is actuated first, the air in the expansion cylinder will be exhausted and the nail setting machine will return to a safe non-operational state. For this reason, contact hitting is prevented. In addition, if you leave the trigger valve operating (i.e., pull the trigger lever) when firing a rivet, the pressing part of the contact arm will not continuously press against the workpiece due to the reaction when driving the rivet machine. , it is safe because dribbling is prevented. Furthermore, the one-cycle valve automatically connects the upper chamber of the head valve directly to the main chamber by operating the trigger valve based on the firing operation, making the upper chamber of the head valve uncontrollable. It is possible to prevent an outburst. Furthermore, if the trigger lever is kept pulled after the stud is fired, the pressing operation of the contact arm will be disabled, but even if some force is applied and the tip of the contact arm operates the valve stem, Because the valve housing of the one-cycle valve is vented to equal atmospheric pressure, the valve remains stationary and the one-cycle valve maintains the fastener in a safe inoperable condition. Therefore, the safety of the fastener setting machine is ensured in this respect as well, and the fastening machine can be operated safely at all times.

[Brief explanation of the drawing]

FIG. 1 is an overall view showing the safety device of the fastener A of the present invention together with the main parts of the fastener A, FIGS. 2 a and b are explanatory diagrams of the operating state of the trigger valve, and FIG. It is a summary explanatory diagram of the air communication state of
Figures 4a and 4b are explanatory diagrams of the operating state of the one-cycle valve and contact arm. Code A...tacker, 2...injection port, 3...tack,
4... Contact arm, 5... Workpiece, 6...
...Trigger lever, 7...Trigger valve, 8...Main chamber, 9...Head valve, 10...Head valve upper chamber, 15...Trigger valve control chamber,
16...Trigger valve stem, 20...One cycle valve, 21...Valve cap, 22...
Valve housing, 23... valve, 24... valve stem, 25... void, 26... throttle hole,
29... Coil spring, 30... Lower chamber, 31... First arm, 32... Second arm, 33, 36...
Lower end, 34, 35... Upper end, 37... Expansion cylinder, 38... Opening.

Claims (1)

[Claims] 1. A contact arm that protrudes from the tip of the injection port of the nailing machine and has a pressing portion against the workpiece surface, and one end communicates with the trigger valve control chamber,
The other end faces the valve stem actuated by the contact arm, and further includes a cavity opening at both ends and having a throttle hole formed on the trigger valve side, and is biased by a spring toward the trigger valve side;
When air is supplied from the trigger valve control chamber, the head valve and the main chamber are in communication with each other by air pressure and spring pressure acting on both ends of the valve body, and when the valve stem is operated, the trigger valve is operated with air retained in the cavity. When the trigger valve is actuated, air is exhausted from the trigger valve control chamber, and after a predetermined time delay, the remaining air pressure in the cavity and the spring bias are adjusted. The one-cycle valve is housed in a cylinder formed at the end of the contact arm, and is supplied with air introduced into the cylinder from the trigger valve control chamber. and an actuating member that extends the valve stem into an actuable state.