JPH0617801A - Safety valve device - Google Patents

Abstract

PURPOSE: To eliminate a negative effect on a response time of a safety valve by proving a directional control valve for controlling working fluid to a housing cylinder of a corresponding working cylinder between each chamber and a corresponding pilot valve. CONSTITUTION: When pilot valves 58, 60 are positioned at switching positions, hydraulic pressure is applied downward to working pistons 84 of directional control valves 80, 82 to close escape ports 90. Working pistons 86 of the directional control valves 80, 82 disengage from the valve seats. Crossing conduits 94, 96 communicate with chambers 44, 46. Working fluid flow from the chamber 44, 46 into housing cylinders above working pistons 18, and move valve rods 16 to switching positions. Consequently, an inlet port P is communicated with a working port A, and a working port B is communicated with an outlet port S, and other port is closed. Therefore, working fluid flows from the working port A into a chamber 17, and a plunger 15 moves to the right. Thus, the chamber volume can precisely be set, and the response time can be kept constant without being affected by volume of the pilot conduit.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a safety valve device for controlling the flow of pressure fluid to a fluid actuated system such as a double acting cylinder of a power press, and more particularly to an inlet port, a working port and an outlet. A pair of valve stems are included to control the flow of pressure fluid to and from the ports, each of which is slidable within a housing cylinder that is part of the valve chamber, and the pressure fluid is A safety valve arrangement of the type having a main control valve, such as including a working piston which is operatively connectable to a reservoir for enabling an action on the working piston of the valve stem. .

[0002]

2. Description of the Related Art One of safety valve devices of this type is disclosed in US Pat.
No. 4,748,896 and includes a pair of pilot valves by which the two valve stems are each controlled to be shiftable between two actuated positions of the valves. These pilot valves are located outside the actual main control valve and are connected thereto via respective pilot passages. That is, each pilot valve requires two pilot passages to connect with its main control valve, one pilot passage leading to its corresponding reservoir, and the other pilot passage It leads to the working piston of the associated valve stem.

One of the drawbacks of this form is that each pilot passage between the pilot valve and each reservoir has a negative effect on the internal switching time, or response time, of the safety valve device. The reason is that the volumes of these pilot passages bring about an effective volume expansion of each storage chamber. That is, the pilot passages must be sized and maintained throughout their placement,
This limits the versatility and availability of the safety valve device. Further, it is possible that the pilot passages connecting the pilot valves with the safety valve arrangement may be inadvertently reversed during installation, thereby defeating the safety characteristics of the valve arrangement.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is therefore to provide an improved safety valve device in which the abovementioned drawbacks are eliminated.

[0005]

This object, and various other objects that will become apparent later, are provided in accordance with the invention by providing a directional control valve between each reservoir and its corresponding pilot valve. Achieved by Suitably, respective cross passages are provided for connecting both directional control valves to the housing cylinders of both working pistons, and the directional control valves and each cross passage are preferably integrated into the housing. It is good to have been done.

By directly connecting the storage chambers to the housing cylinders of the respective working pistons via their crossing passages, the volumes of the storage chambers can be precisely sized, and the internal response time can be set by the pilots. It remains unaffected by the volume of the passage. The maximum permissible time difference between the actuations of the pilot valves is determined exclusively by the size of the volume of the reservoirs and the size of the respective through-holes connecting the reservoirs to the valve chamber containing the valve stem. .

As described above, the safety valve device according to the present invention is
It eliminates the need for adjustment of various parts between the main control valve and each pilot valve, which influence safety. Since the main control valve is supplied with pressure fluid directly from the reservoirs and the cross-passages are housed in the valve housing, the drawbacks hitherto experienced are essentially eliminated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to specific embodiments shown in the accompanying drawings. In all of these drawings, the same or corresponding members are always designated by the same reference numerals. Referring to the accompanying drawings, and in particular to FIG. 1, this shows a longitudinal cross section of a safety valve device, generally designated by the reference numeral 10, which is, for example, a longitudinally slidable plunger. A device for controlling a fluid actuation system, such as a double-acting cylinder element 14, which is provided with 15 and thus the interior of the cylinder 14 is divided into two chambers 17, 19. This safety valve device 10 has a housing 1
2 including one inlet port P, two working ports A and B, and two outlet or return ports R and S
The working port A is in communication with the chamber 17 via the supply line 21 and the working port B is in communication with the chamber 19 via the supply line 22 so that the pressurized fluid can flow through the plunger 15 It is supplied to both sides of this one so that reciprocating motion of this one can be achieved.

The housing 12 contains a pair of valve stems 16 which are arranged parallel to each other in respective valve chambers 23 and inside the housing 12 in respective longitudinal directions. Can move. Each valve rod
16 includes a working piston 18 at one of its shaft ends, which is engageable with a valve seat 24 and is slidable in a housing cylinder 25 in the upper part of its valve chamber 23. At some distance from this working piston 18, each valve stem 16 has a central double valve piston 2
0, which is connected to each other by a rod 22c of reduced diameter to form a generally annular gap 26, an upper valve member 20a and a lower valve member 20b.
And the upper valve member 20a of each valve stem 16
Controls valve seat 27, and lower valve member 20b
29 and the valve seat 31 can be engaged. The valve chambers of the two valve rods 16 facing each other 23
A pair of intersecting passages 28, 30 are provided to connect the respective annular spaces 26 of the. In addition, in their upper region each valve chamber 23 is connected via a passage 33.

At the other shaft end, the valve stems 16 are equipped with an inverted U-shaped, spring-biased control piston 32. Both control pistons 32 control the flow of fluid inside a passage 34 extending between the working port B and the outlet port S, and they are arranged in series along the passage 34.

The operation of the safety valve device 10 is effected by activating a pair of preliminary control valves, namely pilot valves 58, 60, which pilot valves are operated manually, mechanically or electrically. , Electromagnetically, or by pressure, or by any other suitable means. Inside the housing 12 there are provided reservoirs 44 and 46, which are designated for the pilot valves 58, 60 respectively, both reservoirs 44, 46 via the through-hole 48. And communicates with the valve chamber 23.

A spring-biased check valve 68 is located in the passageway between the inlet port P and the valve chamber 23 and prevents backflow of pressurized fluid into the inlet port P. A guide groove 70 is branched from the inlet port P to direct the pressure fluid to the chamber 72, and a relief valve 74 is provided in the chamber. The relief valve 74 is biased in the opening direction, for example by a spring (not shown). A through hole 73 is connected to the storage chamber 44 and the chamber 72, and this through hole is normally formed.
The pressure fluid flowing from the inlet port P into the chamber 72 is closed by the relief valve 74 when it is pressed against the through hole 73. While the supply of pressure fluid is shut off, its relief valve 74 is open and the reservoir 44 has a through hole 7
Connected to the outside air via 5.

As further shown in FIG. 1, each reservoir 4
4 and 46 are in communication with a chamber 76, in which spring-loaded directional control valves 80, 82 are provided, the directional control valve 80 thus corresponding to the reservoir 44 and the pilot valve 50.
Is inserted in the passageway between and and the directional control valve
82 is inserted in the passage between the storage chamber 46 and the pilot valve 60. Each directional control valve 80, 82 is provided with a working piston 84 at its one shaft end and a valve piston 86 at the other shaft end, to which the spring 77 acts. Has been. Each room 76
Is controlled by working piston 84 Control port 92
And escape port 90, and further working port 88
Is included. A pair of cross passages 94, 96 connect each working port 88 of each directional control valve 80, 82 to each working piston 18
Directly connect to housing cylinder 25 of. The control ports 92 of the directional control valves 80 and 82 are connected to the pilot valves 58 and 60 by the pilot passages 96 and 100, respectively.
Is bound to. Supply line 102 connects both pilot valves 58, 60 to a pressure supply not shown.

Having described the individual components and structure of the safety valve device 10 according to the present invention, the mode of operation thereof will now be described in more detail. FIG. 1 shows the safety valve arrangement 10 in its idle position, in which case both control valves 80,
82 is each pilot passage 98, 100 and each pilot valve 5
8 and 60 are breathing through. Similarly, each working piston 18 is vented through its respective cross passage 94, 96 and each relief port 90 of both directional control valves 80, 82. Each valve stem 16 is pushed into its respective upper position by a respective spring-loaded control piston 32, in which the inlet port P is connected to the working port B, while the working port B and the outlet port S are connected. The passage between and is closed by each control piston 32, and the working port A is in open communication with the outlet port R. Thus, pressure is built up through the supply line 22 into the chamber 19 of the cylinder 14, but the other chamber 17 is open to the outside, which causes the plunger 15 to move to the left. The pressure in the reservoirs 44, 46 pushes the valve pistons 86 of both directional control valves 80, 82 to their upper position.

As shown in FIG. 2, each pilot valve 58,
Each working piston of both directional control valves 80, 82 when 60 is activated to occupy its switching position.
At 84, the pressure of the pressure fluid 84 is exerted to move downwards against the force of the spring 77 and each corresponding relief port 9
Close 0. The respective working pistons 86 of the respective directional control valves 80, 82 are disengaged from their corresponding valve seats so that the respective cross passages 94, 96 are arranged in their respective working ports.
It connects to each storage room 44 and 46 via 88. That is,
Pressure fluid flows from each reservoir 33, 46 via their open directional control valves 80, 82 and each cross passage 94, 96 above the working piston 18 of each valve rod 16 and the housing cylinder above.
Inflow into 23 to move the stems 16 to their switching positions. Therefore, the communication between the inlet port P and the working port B is blocked by the lower valve member 20b of each valve piston 20, while the communication between the inlet port P and the working port A is opened. Similarly, the communication between working port B and outlet port S is opened, while the communication between working port A and outlet port R is blocked. Thus, the pressurized fluid flows from the working port A through the supply line 21 into the chamber 17, whereby the plunger 15 is moved to the right.

Referring now to FIG. 3, this shows an example of a malfunction of the safety valve device 10, in which only the pilot valve 58 is activated, whereas the pilot valve 60 is deactivated. It remains activated (relief position). That is, the pressure fluid flows through the cross passage 94 to the housing cylinder 25 above the working piston 18 of the right valve stem 16 thereby moving the valve stem downwards into the switching position whereby the reservoir 46 is Through hole 4
8 and via exit port R. The reservoir 46 is pressureless, so that no pressure can act on the valve piston 86 of the right-hand directional control valve 82 and this control valve is held in its upper position by the force of the spring 77. Even if the pilot valve 60 is actuated at this point, the actuation of its directional control valve 82, i.e. the switching, remains ineffective because the reservoir 46 is pressureless, so that the working piston 18 on the left has no pressure fluid. Pressure does not work and therefore cannot occupy its switching position. Therefore, its safety function is maintained.

In the above type of safety valve device, activation of both pilot valves 58, 60 must occur within a certain time interval, since otherwise its safety function is triggered. Is. This time interval can be, for example, 0.5 seconds.

By connecting each storage chamber 44, 46 directly to the housing cylinder 23 of each working piston 18 via crossing passages 94, 96, the volume of each storage chamber 44, 46 can be precisely dimensioned. , And its internal response time can remain unaffected by the volume of the pilot passages. The maximum permissible time difference between actuation of each pilot valve 58, 60 depends on the size of the volume of each storage chamber 44, 46 and the connection of each storage chamber 44, 46 with each valve chamber 25 in which each valve rod 16 is housed. It is solely determined by the size of the through hole 48 that is formed.

The external pilot valves 58, 60 can therefore be provided with optional pilot passages 98, 100. Moreover, the control pressure via supply line 102 can be supplied individually and may deviate from the level of main pressure at inlet port P.

Although the present invention has been described and described as one of the safety valve devices, many modifications and structural modifications are possible without departing from the technical scope of the present invention. It is not intended to limit the invention to the above description only. What is believed to be novel and desirous of being protected by a patent is set forth in the following claims.

[Brief description of drawings]

1 an embodiment of a safety valve device according to the invention,
FIG. 3 is a longitudinal cross-sectional view of a non-actuated state having a normally closed pilot valve.

2 is a longitudinal sectional view of the safety valve device of FIG. 1 in a switching position by an activated pilot valve.

3 is a longitudinal cross-sectional view of the safety valve device of FIG. 1 with one of the pilot valves in a non-actuated, defective position.

[Explanation of symbols]

 10 Safety Valve Device 12 Housing 14 Double-acting Cylinder 15 Plunger 16 Valve Rod 17 Chamber 18 Working Piston 19 Chamber 20 Central Double Valve Piston 21 Supply Line 22 Supply Line 23 Valve Chamber 24 Valve Seat 25 Housing Cylinder 26 Annular Gap 28 Crossing Passage 29 Valve Seat 30 cross passage 32 control piston 44 storage chamber 46 storage chamber 48 through hole 58 pilot valve 60 pilot valve 68 check valve 70 guide groove 74 relief valve 80 directional control valve 82 directional control valve 84 work piston 86 work piston 88 work port 90 Escape port 92 Control port 94 Crossing passage 96 Crossing passage 98 Pilot passage 100 Pilot passage A Working port B Working port P Inlet port R Outlet port S Outlet port

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[Procedure amendment]

[Submission date] April 13, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

Claims (4)

[Claims] 1. A safety valve device for controlling the flow of a pressurized fluid to a fluid working system such as a double-acting cylinder of a power press, wherein an inlet port and an outlet port are operatively connected to the fluid working system, respectively. And a working port with a working port, each having a working piston (wherein this working piston is in a housing cylinder connectable to a reservoir to allow a pressurized fluid to act on it). Slidable) and a pair of valve rods arranged parallel to each other in the housing and actuated by respective pilot valves, and controlling the flow of pressure fluid from the reservoir to the housing cylinder of the working piston. For safety, including a pair of directional control valves disposed in a passage between the reservoir and each of the associated pilot valves. The valve device. 2. The safety valve device of claim 1, further comprising a cross passageway for coupling the directional control valve to the housing cylinder of the working piston. 3. The safety valve device of claim 1, wherein the directional control valve and the cross passage are integrated into the housing. 4. A safety valve device for controlling the flow of pressure fluid to a fluid working system such as a double-acting cylinder of a power press, wherein an inlet port and an outlet port are operatively connected to the fluid working system, respectively. And a working port with working ports, each having a working piston slidable in a housing cylinder connectable to a reservoir for controlling the flow of pressure fluid between each corresponding port. A main valve means including a pair of valve stems adapted to allow pressure fluid to act on the lever working piston; two valve actuations of the main valve means operatively coupled to the main valve means. Second for providing switching between positions
Of said reservoirs and said associated pilot valves for controlling the flow of pressurized fluid from said reservoirs to said housing cylinders of said working pistons by means of said second valve means and said second valve means. The safety valve device including a third valve means interposed between.