JPS6159876B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve device for supplying and shutting off compressible fluid to an output section, such as in a pneumatic nailer.

2. Description of the Related Art Valve devices provided in conventional driving machines include those having structures shown in FIGS. 1 and 2. That is, the valve shown in FIG. 1 performs the following operation by pulling the trigger. The plunger rises, the compressible fluid supply part opens, the exhaust part closes, and the compressible fluid accumulated in the handle part is supplied to the upper surface of the collar provided in the cylinder, which acts as an output valve. The cylinder is lowered and compressible fluid is supplied to the upper surface of the output piston, driving the output piston.

The valve shown in FIG. 2 operates as follows by pulling the trigger. When the plunger rises, the compressible fluid supply part is closed and the exhaust part opens, and the compressible fluid supplied to the top surface of the head valve is discharged from the exhaust port of the valve, causing the head valve to rise and the output piston to move. drive

Both valves can be operated regardless of the pressure supplied to the driving machine body.
When used at high pressures that are outside the appropriate operating pressure range, undesirable safety issues such as excessive force being applied to each part, shortening the life of the product, and damage to the housing, which is a pressure vessel, were undesirable. . There is also a method in which compressed air flows out from the valve section when the pressure becomes high, but this method has the disadvantage that a large amount of compressed air flows out from the valve section, wasting the air.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, increase the safety of equipment using this type of compressible fluid, and maintain the expected life of the product without wasting air. be.

The present invention focuses on the fact that the push-up load on the plunger varies depending on the pressure of the compressible fluid supplied to the driving machine body, and the present invention has developed the plunger in at least two
The upper plunger is divided into parts and connected through an elastic body such as a compression spring, and the upper plunger is under pressure.
By devising the relationship between the elastic body and the lower plunger to which manual force is applied, the upper plunger does not operate when pressure is high, and the upper plunger operates normally when the supply air pressure is readjusted to the appropriate pressure. It is something.

The overall configuration of the driving machine is shown in FIG. 3, and FIG. 4 is an enlarged cross-sectional view of the control valve 7 according to the present invention. In FIG. 3, the output section consisting of a cylinder, output piston, etc., and the air passage from the on-off valve to the output valve are the same as those shown in FIG. 1.

FIG. 4 shows an on-off valve, that is, a control valve 7.
This shows the state when compressible fluid is supplied to the main body without operating the O
Since the O° ring 24 and the inclined surface portion 36 of the valve bushing 9 contact each other to close the supply port 35, the compressible fluid does not flow downward and is blocked, while the O° ring 25 attached to the plunger 22 closes the supply port 35. Since it is not in contact with the inner surface 37 of the output valve, the air passage 11 communicating with the output valve communicates with the atmosphere via the exhaust passage 23. Therefore, the output piston 6 is not driven.

FIG. 5 shows the state of control valve 7 after operation when trigger 10 is pulled while compressible fluid within the proper pressure range is being supplied. The plunger 20 and the plunger 22 are raised, the O-ring 24 and the inclined surface part 36 of the valve bushing 9 are separated, and the supply port 35 is opened.The O-ring 25 is brought into close contact with the inner surface 37 of the valve bushing 9, and the exhaust passage 23 is closed. The sexual fluid is supplied to the output valve through the air passage 11 and as a result drives the output piston 6. In FIG. 5, the force pushing up the plunger 22 by pulling the trigger 10 is P _B , and the pressure receiving surface 26, which is a part of the plunger 20, receives the pressure of the compressible fluid, and the plunger 20
Assuming that the force acting on the plunger spring 21 is P _A and the set load of the plunger spring 21 is P ₁ , the force relationship P ₁ ≧P _B ≧P _A holds true within an appropriate pressure range.

On the other hand, FIG. 6 shows the state after the control valve 7 is operated when the trigger 10 is pulled when high-pressure compressible fluid is being supplied to the driving machine main body.
Since the supplied compressible fluid is at high pressure, the set load P _S1 of the plunger spring 21 does not satisfy the above equation, and the load when the plunger spring 21 is deflected is expressed as P ₂ as shown in FIG. Then, the power relationship of P ₂ ≧P _B ≧P _A is also not satisfied. That is, P
The relationship is _A ≧P _B ≧P ₂ . Therefore, although the exhaust passage 23 is closed by the O-ring 25, the O-ring 24 and the inclined surface portion 36 of the valve bush 9 do not open, and therefore the supply port 35 does not open, so even if the trigger 9 is pulled, the compressible fluid is not released. The output piston 6 cannot be driven because it is not supplied to the output valve.

The plunger spring 21 in FIG.
Although it is set to have a set load of P ₁ , the set load of the plunger spring 21 is
A similar effect is produced even if P ₁ =0, that is, the plunger spring 21 is freely attached. There is a pressure reducing valve (not shown) in the middle of the hose that supplies compressed air from the compressor to the main unit to adjust the normal pressure, but if the pressure is reduced and returned to the appropriate pressure, the control valve will operate normally. return.

Figure 7 shows the conventional driving machine shown in Figure 2.
This is a valve showing a modified example for applying a control valve that produces the effects of the present invention. That is, when the trigger 10 is not pulled, compressible fluid is supplied to the upper surface of the head valve through the air passage as shown in FIG. When the trigger 10 is pulled within the appropriate pressure range, the force relationship P ₁ ≧P _B ≧P _A is established as described above, and the O° ring 33 attached to the plunger 30 and the handle 3 The seal surface 34, which is a part of the head valve, seals and cuts off the supply of compressible fluid, and at the same time, the O-ring 32 and the inclined surface of the valve bush 9 open, so that the compressible fluid that was being supplied to the upper surface of the head valve is replaced by air. It passes through the passage 11 and the exhaust passage 23 and is discharged to the atmosphere, the head valve rises, and the output piston 6 is driven. On the other hand, when the trigger 10 is pulled during high pressure, the load on the plunger spring 21 is P _A ≧P _B ≧P as described above.
In order to satisfy the relationship _S2 , the output piston is not driven for the reasons mentioned above.

According to the present invention, since the upper and lower plungers are connected through an elastic body such as a compression spring, when the plunger spring is deflected by the stroke amount of the lower plunger, compressible fluid pressure is generated in the plunger spring. When a force greater than P _S2 acts on the upper plunger, the upper plunger will not operate even if the trigger is pulled, and the output piston will not be driven. Therefore, air is not wasted unnecessarily, and the driving machine cannot be operated at high pressures outside the appropriate pressure range, thus maintaining the life expectancy of the product as originally expected. .

[Brief explanation of the drawing]

1 and 2 are side longitudinal sectional views of an output section and a valve section of a conventional driving machine. FIG. 3 is a side view showing the entire driving machine according to the present invention, FIG. 4 is an enlarged vertical sectional view showing one embodiment of the control valve according to the present invention, and FIGS. FIG. 3 is an enlarged vertical cross-sectional view showing a state when the control valve shown in the figure is in operation. FIG. 7 is an enlarged longitudinal sectional view showing a modified embodiment of the control valve according to the present invention. In the figure, 1 is the driving machine body, 6 is the output piston, 5 is the cylinder collar, 12 is the head valve, and 7
9 is an on-off valve (control valve), 9 is a valve bush, 10 is a trigger, 21 is a plunger spring, and 20 and 22 are plungers.

Claims (1)

[Claims] 1. A driving machine equipped with an output piston that performs a driving operation, an output valve that drives the output piston, an on-off valve that supplies and discharges compressed fluid to the output valve, and a trigger that operates the on-off valve,
The plunger of the opening/closing valve is divided into at least two parts each having an elastic body interposed therein, so that the plunger is configured to be expandable and retractable depending on the pressure of the compressed fluid, and under normal pressure, the plunger can be expanded and contracted according to the pressure of the compressed fluid. When the plunger moves integrally to supply and discharge the compressed fluid, and the compressed fluid used reaches excessive pressure, the elastic body built into the plunger is compressed in response to the movement of the trigger. A control valve for a driving machine, characterized in that the control valve is configured to maintain the compressed fluid supply port in a closed state.