JP3369963B2 - Valve opening / closing mechanism and gun nozzle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve opening / closing mechanism and a gun nozzle.

[0002]

2. Description of the Related Art Generally, a gun nozzle for cleaning uses a valve such as a ball valve or a conical valve for a small flow rate of 30 liter / min or less, and a large flow rate of 50 liter / min or more. A flat valve type valve is used in the one. As a conventional valve opening / closing mechanism for a gun nozzle using a flat valve type valve, there is a manual type as shown in FIG. The valve opening / closing mechanism of the gun nozzle presses the valve body 22 against the seat portion 10b of the valve seat 10 by the force of the compression coil spring 21, and further, when supplying the cleaning water,
The force of the high-pressure water supplied from the water inlet of the socket 5 into the valve chamber acts as a pressing force for pressing the valve body 22 against the valve seat 10. Thus, the water inlet side and the nozzle (not shown) side are normally shut off by the valve opening / closing mechanism, and the flow path 10a is closed.
The rod 23 for operating the valve element 22 to move back and forth and the valve element 22 are provided independently of each other.

In this state, the lever 7 of the gun nozzle is shown in FIG.
When the rod 23 is pushed by operating from the position shown by the solid line (valve closed position) to the position shown by the broken line (valve open position), the valve body 22 is pushed upward by the upper end portion of the rod 23, and together with the rod 23. The valve body 22 moves to the valve open position side in the upper part of the figure. Therefore, as shown in FIG. 6, the valve body 22 is separated from the seat portion 10b of the valve seat 10, and the flow passage 10a is opened. As a result, high-pressure water flows from the water inlet side of the socket 5 to the opening of the valve seat 10 and the flow path 1
0a, the lance 4, etc., and flows into a nozzle (not shown), from which it is jetted to the outside as high-pressure water for cleaning. In FIG. 5, the valve body 22, the rod 23, and the compression coil spring 21 are located when the lever 7 is located at the solid line position (valve closed position: injection stop position) on the left half side of the center line C2 in the drawing. The respective member positions are shown, and the half part on the right side of the center line C2 in the drawing shows the respective member positions when the lever 7 is positioned at the broken line position (valve open position: injection position). In addition, 1 is a body,
24 is a cap screwed into the body 1, 3 is a pipe connecting the socket 5 and the body 1, 6 is a hand guard,
Reference numeral 8 is a pin that is planted in the body 1 and rotatably supports the lever 7, reference numeral 9 is a grip that accommodates the socket 5 and the pipe 3 therein, 16 and 18 are O-rings, and 17 is a backup ring.

As another conventional gun nozzle, FIG.
And there is a gun nozzle as shown in Figure 8 ("Industrial cleaning").
Published by Japan Cleaning Association June 24, 1988 P. 116
~ 118). In such a gun nozzle, in the unloaded state in which pressure water is not jetted, the main valve 111 is
It is pressed against the valve seat 106 by the spring force of a pressure ring 114 set behind the lever pivot 108. The pressure water sent out by the high-pressure pump flows into the chamber A, and the main valve 111
Through a slight gap between the cylinder 105 and the cylinder 105 and flows into the B chamber. In this state, the high-pressure water in the chamber A and the high-pressure water in the chamber B have the same pressure, but the main valve 111 is pressed against the valve seat 106 by the pressure in the chamber B and the spring force of the pressure spring 113, and the pressurized water is not jetted. . next,
When the lever 103 is gripped, the lever pivot 108 is pushed backward, and the control valve 107 connected by the set bolt 112 also moves backward at the same time. At this time, the tip of the control valve 107 and the main valve 11
1, the pressure water that has flowed into the B chamber passes through the hole in the main valve 111 and flows out forward, causing a pressure drop in the B chamber. When the A-chamber pressure overcomes the B-chamber pressure, the main valve 111 moves backward, the valve starts to open, and the pressure water is jetted forward. Lever 103
Then, the main valve 111 is pushed back by the spring force of the pressure spring 114 set behind the lever pivot 108, the valve is closed and the pressure water is shut off, and the state returns to the original state.

[0005]

However, in the conventional valve opening / closing mechanism as shown in FIG. 5 described above, the valve closing direction with respect to the valve body in the valve closing position in the state where high pressure water is supplied. There is a problem that a large force is required to open the valve because a large pressing force is applied to the valve. That is, in order to move the lever 7 from the injection stop position (valve closed position) shown by the solid line in FIG. 5 to the injection position (valve open position) shown by the broken line, the pressing force by the pressure of the high pressure water acting on the valve body 22 is used. And the force equivalent to the sum of the pressing force by the compression coil spring 21 divided by the lever ratio of the lever 7, that is, the force calculated by (pressing force by pressure + pressing force by spring) / (lever ratio) It is necessary to apply a large operating force to the lever 7. Also, during injection (while maintaining the valve open)
Is larger than (force corresponding to the sum of the pressing force due to the pressure acting on the cross-sectional area of the rod 23 and the pressing force when the compression coil spring 21 is further compressed than when it is closed) / (lever ratio) It is necessary to continue to apply operating force. For example, in the case of a gun nozzle that uses high-pressure water of about 5 MPa, an operating force of about 10 kgf was required. For this reason, the fatigue of the operator who operates the gun nozzle has increased.

Further, the gun nozzle shown in FIGS. 7 and 8 has the valve chambers A and B as described above, and since the water pressure of the chamber A is used to open the valve (main valve), the main valve is opened. When closing the valve, a strong return compression spring having a set load to counter the water pressure in the chamber A is required. Therefore, in order to maintain the valve open state, an operating force that opposes not only the pressure spring 113 but also the pressure spring 114, which is a strong return compression spring, is required, and the operator's fatigue increases. There is a point.

As a solution to this, it is conceivable to use a dynamic actuator such as an electric actuator or a fluid pressure actuator to operate the lever. However, the dynamic actuator portion is larger and heavier than the valve body. The larger size makes the device harder to handle, and
Power actuators such as electric motors, electric cylinders, fluid pressure motors, and fluid pressure cylinders have a complicated structure and are expensive, so that the cost of the device is high. Further, there is another problem that the portability is poor because a power source for driving such an electric actuator is required.

The present invention aims to solve such problems. That is, an object of the present invention is to provide a valve opening / closing mechanism and a gun nozzle that have a simple structure, but can reduce the operating force of the operating portion of the valve opening / closing mechanism to reduce operator fatigue.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above problems by reducing the force acting on the operating portion in the valve closing direction. That is, as for the valve opening / closing mechanism of the present invention, in the first aspect of the present invention, the valve chamber (1b) into which high-pressure water flows in and the flow path (10a) fixed to the valve chamber (1b) and capable of discharging high-pressure water. ) And a valve seat (10) having a seat surface (10b) disposed on the inflow side of the high pressure water, and a valve seat (1
0) seat surface (10b) can open and close the first valve surface (11
c) and has a flow path (11a) through which high-pressure water can flow, and the seat surface (11) is provided on the side opposite to the valve seat (10).
b), a first valve body (11), a first spring (14) for urging the first valve body (11) to separate from the seat surface (10b) of the valve seat (10), and a first A second valve surface (13a) capable of opening and closing the seat surface (11b) of the valve body (11) and a second valve surface (13c) projecting from the opposite side of the first valve body (11). The valve body (13), the second valve body (13), the second spring (15) for urging the second valve body (13) to press the seat surface (11b) of the first valve body (11), and the second valve body (13). ), And has a rod (12) which is integral with the second valve body (13) and whose end opposite to the valve chamber (1b) is at atmospheric pressure. By operating the rod (12), Two
An operating portion for moving the valve body (13) forward and backward, and a shaft portion (1
3c) is set to have a cross-sectional area orthogonal to the axial direction of the rod (12) equal to the cross-sectional area orthogonal to the axial direction of the outer end portion of the rod (12), and the axial portion of the second valve body (13) ( The end portion of 13c) opposite to the operation portion is under atmospheric pressure.

According to the first aspect of the present invention, the second valve body (13) is moved to the first valve body (1) by the operating portion.
The fluid in the valve chamber (1b) is pushed by the human force so that the fluid in the valve chamber (1b) separates from the channel (1).
It flows into a), the first valve body (11) is pushed up by the pushing force of the first spring (14), and separates from the valve seat (10). As a result, the fluid flows in between the first valve body (11) and the second valve body (13) and between the first valve body (11) and the valve seat (10). Furthermore, the shaft portion (13c)
By setting the outer end of the operating portion under atmospheric pressure, the force due to the fluid pressure applied to the shaft portion (13c) of the second valve body (13) (upward force in FIG. 2) and the operating portion ( Since it is possible to cancel the force due to the fluid pressure (downward force in FIG. 2) applied to 12), the force in the axial direction due to the fluid pressure is reduced in the operating portion, and the force required to open the valve is greater than in the past. Can be made smaller. That is, by setting the cross-sectional area orthogonal to the axial direction of the shaft portion (13c) to be equal to the cross-sectional area orthogonal to the axial direction of the outer end portion of the rod (12), the valve is opened and the open state is maintained. Since the necessary operating force is only the force that opposes the second spring (15), which is a weak spring force that overcomes the sliding resistance of the shaft portion (13c), the burden on the operator is significantly reduced. Further, it suffices to add a flat valve element (first valve element 11) and a spring (first spring 14) to the valve opening mechanism of the conventional gun nozzle as shown in FIG. Never.

Further, in claim 1, the rod (12) and the shaft portion (13c) of the second valve body (13) are integrally connected, and their cross-sectional areas are set equal to each other. Since the axial force due to the fluid pressure does not act on the operating rod (12), the force required for opening the valve can be made smaller than before, and the fatigue of the operator can be reduced. That is, the shaft portion (13) of the second valve body (13)
In addition to making the cross-sectional area orthogonal to the axial direction of c) and the corresponding cross-sectional area of the rod (12) equal,
c) and the outer end of the rod (12) are under atmospheric pressure, the force due to the fluid pressure exerted on the shaft portion (13c) of the second valve body (13) (the upward force in FIG. 2) , Rod (1
Since all the force due to the fluid pressure applied to 2) (the downward force in FIG. 2) can be canceled out, the operating force of the lever (7) is reliably reduced.

According to a second aspect of the present invention, in the valve opening / closing mechanism according to the first aspect, the rod (12) of the operating portion is provided.
Is provided with a lever (7) for advancing and retracting.
With this configuration, the valve opening / closing mechanism can be easily operated by operating the lever (7).

According to a third aspect of the present invention, in the valve opening / closing mechanism according to the first or second aspect, the second valve body (1
3) has a second valve surface (13a) formed to project from an intermediate portion of the shaft portion (13c), and a seat surface (10b) of the valve seat (10) is provided with a flow path () of the valve seat (10). The cross-sectional area of 10a) is larger than the cross-sectional area of the channel (11a) formed in the first valve body (11). When configured as described in claim 3, the present invention can be applied to a valve opening / closing mechanism of a general fluid pressure device. For example, a valve opening / closing mechanism including a pilot valve and a main valve body.
Here, the pilot valve is used in combination with a valve element that operates at a small flow rate and a pilot spring that is a spring having a small force amount that opposes a small pressure receiving area corresponding thereto. The main valve is a main valve controlled by a pilot valve.

Further, a fourth aspect is characterized in that the valve opening / closing mechanism according to any one of the first, second or third aspects is applied to a gun nozzle. In the case of the construction according to claim 4, the force required for operating the lever (7) of the gun nozzle is small, and in particular, even when the injection state is maintained by the gun nozzle for a relatively long time, the cleaning is performed. It is possible to reduce the fatigue of the worker during work or the like. The reference numerals in parentheses indicate the corresponding members of the embodiment.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment of the Invention) FIG.
The first embodiment of the present invention is shown in FIG. FIG. 2 shows a valve closed state in which the main part of FIG. 1 is enlarged. Further, FIG. 3 shows a valve open state in which the main part of FIG. 1 is enlarged. 1, a body 1 on the left side in FIG. 1 has an inlet port 1a on the right side in the figure, a cap mounting port 1d on the upper side in the figure, an outlet port 1c on the lower left in the figure, a rod fitting hole 1e on the lower side in the figure, and Internal valve seat mounting holes 1f are formed respectively. The cap 2 is screwed into the cap mounting opening 1d of the body 1, and the valve seat 10 is fitted into the valve seat mounting hole 1f.

The cap 2 is formed with a recess into which a shaft portion 13c of a second valve body 13 described later is fitted. A valve chamber 1b is formed by the inner wall of the body 1, the inner wall of the cap 2, the ring-shaped seat surface 10b of the valve seat 10, and the like. Inside the valve chamber 1b, the flow passage 11a and the seat surface 11 are arranged so that they can be seated and separated from the seat surface 10b of the valve seat 10.
b and the first valve body 11 which is the main valve on which the first valve surface 11c is formed, and the second valve surface 13a is formed so as to be able to be seated / separated from the seat surface 11b of the first valve body 11. The first valve 14 and the second valve body 13, which are pilot springs that exert a force to push up the second valve body 13 and the first valve body 11 that are pilot valve bodies from the seat surface 10b of the valve seat 10,
A second spring 15 is provided which exerts a force so as to press it toward the valve body 11.

The first spring 14 and the second spring 15 are, for example, compression coil springs. In addition, in FIG.
In the first valve body 11, the rod (operating portion) 12, the first spring 14 and the second spring 15 which will be described later, a half portion on the left side of the center line C1 in FIG. (Valve closed position: injection stop position) shows the respective member positions, and the right half of the center line C1 in the figure positions the lever 7 at the broken line position (valve open position: injection position). The respective member positions when they are moved are shown.

One end of a pipe 3 is screwed into the inflow port 1a of the body 1. A socket 5 is screwed into the other end of the pipe 3. A grip 9 is provided so as to cover the outer peripheral side of the pipe 3. A lance 4 is screwed into the outlet 1c of the body 1. An end side of the lance 4 (not shown) is connected to a nozzle (not shown). The rod 12 is slidably fitted in the rod fitting hole 1e of the body 1. The second valve body 13 has a substantially conical second shape.
It has a valve surface 13a and a shaft portion 13c extending upward from the valve surface 13a so as to be slidably fitted in the recess of the cap 2, and a through hole 13b is formed in the shaft center portion. A vent hole 20 is formed in the concave portion of the cap 2 so that the end portion of the shaft portion 13c on the side opposite to the rod 12 is under atmospheric pressure in a state where the shaft portion 13c of the second valve body 13 is fitted. .

The rod 12 reaches the upper end side of the shaft portion 13c in the drawing through the flow passage 10a of the valve seat 10, the flow passage 11a of the first valve body 11, and the through hole 13b at the center of the second valve body 13. The stepped portion 12a and the flat head machine screw 19
It is integrally connected to the valve body 13. The countersunk head screw 19 is provided such that the threaded portion is screwed into the upper end portion of the rod 12 and the countersunk portion contacts the conical hole-shaped counterbore surface of the shaft portion 13c.

The outer diameter of the outer end of the rod 12 and the second valve body 1
The outer diameter of the shaft portion 13c of No. 3 has the same dimension. Thereby, as described above, the rod 12 and the second valve body 13 are integrated, and the outer end portion of the rod 12 and the second valve body 13 are integrated.
Coupled with the fact that the outer end of the shaft portion 13c is under atmospheric pressure, the respective axial forces acting on the rod 12 and the shaft portion 13c of the second valve body 13 at the time of valve opening are applied. Can be offset. That is, when the valve is opened (the moment when the second valve body 13 separates from the first valve body 11), the rod 12 is not subjected to the axial force due to the pressure of the high-pressure water and the second spring 1
Only the pressing force of 5 and the lifting force of the first spring 14 act. The second spring 15 has a shaft portion (13
A weak spring force sufficient to overcome the sliding resistance of c) is sufficient.

Therefore, the operating force required to push in the rod 7 is (the force of the second spring 15-the force of the first spring 14).
It should be larger than. The pressing force acting on the seat surface 11b (upper surface in the figure) side of the first valve body 11 by the high-pressure water in the valve chamber 1b (the seat surface of the second valve body 13 and the first valve body 11) The sum of the pushing force acting on the valve face 11c (the upper face in the figure) and the pushing force of the first spring 14 (which is due to the high-pressure water flowing into the outlet 1c side from between 11b and 11b) is larger. The mounting load of the first spring 14 is set so that

On the lower side of the body 1 in FIG. 1, a lever 7 is supported by a pin 8 so as to be rotatable between a position shown by a solid line (valve closed position) and a position shown by a broken line (valve open position). ing. The lower end of the rod 12 is in contact with the lever 7. A hand guard 6 is provided on the lower side of the lever 7 in the figure so as to prevent filth and dirty water from getting into the hands during the cleaning work. In addition, 16 is an O ring,
It is used both for sealing the fitting portion between the concave portion of the cap 2 and the shaft portion 13c of the second valve body 13 and for sealing the fitting portion between the body 1 and the rod 12, and 17 is a backup ring. Reference numerals 18 denote O-rings that seal the fitting portion between the body 1 and the cap 2.

Next, the operation of the first embodiment will be described. High-pressure water flows from the water inlet on the socket 5 side through the flow passage 1a of the body 1 into the valve chamber 1b, and with the lever 7 in the valve closed position shown by the solid line in FIG. No pressure acts on the 1c side, and the force due to the pressure of the high-pressure water in the valve chamber 1b presses the first valve body 11 against the seat surface 10b of the valve seat 10 and causes the second valve body 13 to move to the first side.
It is pressed against the seat surface 11b of the valve body 11. Further, the force of the second spring 15 in the valve closing direction acts, and the force of the first spring 14 in the valve opening direction also acts.

In this state, the upper end of the shaft portion 13c of the second valve body 13 in the drawing and the lower end portion of the rod 12 integral with the shaft portion 13c are under atmospheric pressure, so that the high pressure acting on the second valve body 13 is high. The force of water is greater than that of the conventional one shown in FIG.
3c (or rod 12) is reduced by an amount corresponding to the sectional area. Further, since the force in the valve opening direction by the first spring 14 is applied, the force in the valve closing direction acting on the second valve body 13 is further reduced.

In this state, when the lever 7 is operated in the valve opening direction shown by the broken line in FIG. 1, the rod 12 and the second valve body 13 integrated with the rod 12 are operated with a force much smaller than the conventional one as described above. It can be moved upwards. As a result, as shown in FIG. 3, the second valve body 13 is separated from the seat surface 11b of the first valve body 11 (however, the first valve body 11 is in a transitional state where it is not yet separated from the valve seat 10). Flow path 11a of the first valve body 11 and the flow path 1 of the valve seat 10.
A small amount of high-pressure water flows through the outlet 0a toward the outlet 1c,
The force that pushes the valve element 11 in the valve opening direction increases. Further, the first valve body 11 from which the pressing force of the second valve body 13 has been released,
It is pushed upward in the drawing by the pushing force of the first spring 14 in the valve opening direction.

In this way, the first valve body 1 made of high pressure water is used.
The second valve body 13 is more than the pressing force acting on the upper side surface in FIG.
And the seat surface 11b of the first valve body 11 from the outlet 1c
Since the push-up force acting on the lower side surface in the figure and the push-up force of the first spring 14 due to the high-pressure water flowing into the side become larger, the first valve body 11 moves from the seat surface 10b of the valve seat 10 as shown in the figure. Leave. As a result, in addition to a small amount of high-pressure water passing through the flow path 11a of the first valve body 11 as shown by the upper arrow in FIG. 3, a large amount of high-pressure water as shown by the lower two arrows in FIG. Then, it flows from the inflow port 1a side to the outflow port 1c side through the flow path 10a of the valve seat 10, and is supplied to the nozzle via the lance 4.

In order to maintain the injection state for a relatively long time during the injection of high-pressure water, it is sufficient to oppose only the force of the second spring 15 acting on the rod 12 in the valve closing direction. Can be small. When the lever 7 is released, the second valve body 13 is pushed out by the second spring 15 and comes into contact with the first valve body 11, and further the first spring 14 is compressed, so that the first valve body 11 moves to the valve seat 10. It is pressed. When the first valve body 11 comes into close contact with the valve seat 10, the high-pressure water pressure is applied to the first valve body 11 and the valve is closed.

(Second Embodiment of the Invention) FIG. 4 shows a second embodiment of the present invention. This is the second valve body 1 having the conical surface-shaped second valve surface 13a in the first embodiment.
Instead of 3, the second valve body 13 'having a flat second valve surface 13'a is used. That is, in the second embodiment, both the first valve body 11 and the second valve body 13 'are flat valve-shaped. The operation of the second embodiment is that the flow rate passing between the lower surface of the flat valve-shaped second valve body 13 'in the figure and the seat surface 11b of the first valve body 11 is the first.
The third embodiment is similar to the first embodiment except that it can be provided more than that of the first embodiment, and thus detailed description of the operation is omitted.

In the above description of the first embodiment, the second valve body 13 has the substantially conical second valve surface 13a, but a ball-shaped valve portion (spherical valve portion). May be included. Further, although the rod 12 and the second valve body 13 are screw-coupled in the description of each of the above-described embodiments, these may be integrated. In this case, the intermediate portion of the rod-shaped portion is projected to the outer diameter side, and the valve surface is formed on this protruding portion.

[0030]

EXAMPLE When the operating force of the lever 7 at the time of high-pressure water injection was measured using a device having a conventional structure as shown in FIG. 5, when the pressure of the high-pressure water supplied was 5 MPa, it was 10 kg.
An operating force of f or more was required. On the other hand, in the device of the present invention shown in FIG. 1, the operating force of the lever 7 was 1 kgf under the same pressure condition, and could be made about 1/10 of the conventional force.

[0031]

As described above, according to the present invention, the valve can be opened with a smaller operating force than before, so that the fatigue level of the operator can be reduced as compared with the prior art. The structure of the valve opening / closing mechanism is very simple, and the device can be made relatively inexpensive. In the case of the construction as set forth in claim 1, since the force due to the fluid pressure applied to the shaft portion of the second valve body and the force due to the fluid pressure applied to the rod can be offset, the lever operation force is ensured. Can be reduced to Further, since it is only necessary to add a flat plate-shaped valve element and a spring to a valve opening mechanism such as a conventional gun nozzle, it is not necessary to upsize the device, and the device can be manufactured at low cost. In the case of the configuration according to claim 2, the lever facilitates the operation of the valve opening / closing mechanism. When configured as described in claim 3, the present invention can be applied to a valve opening / closing mechanism of a general fluid pressure device such as a pilot valve. According to the fourth aspect, it is possible to provide a gun nozzle with a small lever operating force. By using such a gun nozzle, it is possible to remarkably reduce the fatigue of the operator, especially when the injection state is maintained for a relatively long time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a gun nozzle showing a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of FIG. 1, showing a closed state of a valve.

FIG. 3 is an enlarged cross-sectional view of a main part of FIG. 1, showing an open state of a valve.

FIG. 4 is a cross-sectional view of a gun nozzle showing a second embodiment of the present invention.

FIG. 5 is a sectional view of a conventional gun nozzle.

6 is an enlarged cross-sectional view of a main part of FIG. 5, showing an open state of the valve.

FIG. 7 is a schematic cross-sectional view showing another conventional gun nozzle.

8A and 8B are views for explaining the operation principle of the injection of the gun nozzle of FIG. 7, FIG. 8A is a view showing a non-injection state, and FIG.
[Fig. 4] is a view showing a state where the gun lever is started to be gripped, and (c) is a view showing an injection state.

[Explanation of symbols]

1 body 1b valve chamber 7 Lever (operation part) 8 pin 9 grip 10 seat 10a flow path 10b seat surface 11 First valve body (main valve body) 11a flow path 11b Seat surface 11c First valve face 12 Rod (operation part) 13 Second valve body (pilot valve body) 13a Second valve face 13b through hole 13c Shaft 14 first spring 15 Second spring 19 Flat head screw 20 vents

Claims (4)

(57) [Claims] 1. A valve chamber (1b) for inflowing high-pressure water, a flow passage (10a) fixed to the valve chamber (1b) and capable of outflowing high-pressure water, and a seat surface arranged on the inflow side of the high-pressure water. (1
0b) having a valve seat (10) and a first valve surface (11c) capable of opening and closing a seat surface (10b) of the valve seat (10), and a flow path (11) capable of inflowing high-pressure water.
a) and a first valve body (11) having a seat surface (11b) on the side opposite to the valve seat (10), and the first valve body (11) having a seat surface (10b) of the valve seat (10).
The first spring (14) for urging the first valve body (11) away from the first valve body (11) and the second valve surface (13a) for opening and closing the seat surface (11b) of the first valve body (11). )
A second valve body (13) having a shaft portion (13c) projecting on the opposite side to the second valve body (13) and a seat surface (11) of the first valve body (11).
a second spring (15) for urging the second valve body (13) to press the second valve body (13), the second spring (15) being integral with the second valve body (13) and the end opposite to the valve chamber (1b). A portion having a rod (12) under atmospheric pressure, and an operating portion for moving the second valve body (13) forward and backward by operating the rod (12), and orthogonal to the axial direction of the shaft portion (13c). Is set to be equal to the cross-sectional area orthogonal to the axial direction of the outer end portion of the rod (12), and the operating portion of the shaft portion (13c) of the second valve body (13). A valve opening / closing mechanism in which the opposite end is under atmospheric pressure. 2. The valve opening / closing mechanism according to claim 1, further comprising a lever (7) for advancing and retracting a rod (12) of the operation portion. 3. The second valve body (13) has a second valve surface (13a) formed so as to project from an intermediate portion of the shaft portion (13c), and the seat surface (10b) of the valve seat (10) is The cross-sectional area of the flow passage (10a) of the valve seat (10) is larger than the cross-sectional area of the flow passage (11a) formed in the first valve body (11). Valve opening and closing mechanism. 4. A gun nozzle having the valve opening / closing mechanism according to claim 1. Description: