US2185402A - Filling valve - Google Patents

Description

Filed March 4, 1937 2 3 l W r/Iu| m 2 2 T 5 2 w 1| 4 1 f 2 M 2 7 J Vw w24 nA 3 2 M 2,/ fn 2 ,M 675- om 2 22 M 2 A 3 /V i M ilf 2 www; 2

Patented Jan. 2, 1940 UNITED STATE-s 2,185,402 Fumo VALVE Richard W. Dinzl, Narberth, Pa., assignor to Baldwin-Southwark Corporation, a corporation of Delaware Application March d, 1937, [Serial N0. 128,998

8 Claims.

This invention relates generally to hydraulic presses and particularly to an improved lling check valve. y

In certain prior types of filling check valves, the

a valve is opened under high pushback pressure which creates a considerable hydraulic shock set up by the oil rushing through the valve. Also, in such prior devices the pilot plunger in suddenly opening the valve is brought to a stop by l@ striking a positive mechanical abutment at the end of the stroke. These conditions are quite objectionable for various reasons one of which is the breakage of the pipe and opening of the pipe joints leading to the iilling check valve operating` 'Hi cylinder. When such a breakage occurs, the press is necessarily shut down until adequate repair can be made.

It is an object of my invention to provide an improved apparatus and system that makes it 2o impossible to establishany appreciable pressure Ain the pushback line of the pushback or return `cylinders until the lling check valve has opened. A further object is to provide an improved construction whose mode of operation is such as to insure quiet opening of the lling valve and to bring the filling valve to a stop Without mechanical shock at the end of its opening stroke.

A further object is to provide an improved filling valve that is relatively simple and economical in construction, operation and maintenance without sacrice of positive and sensitive control. A further obiectiis to provide an improved con struction and arrangement of parts providing a relative simple, compact and eiiicient combined pilot cylinder, bypass and dashpot for filling i check valves.

Other objects and advantages wil be more apparent to those skilled in the art from the following description of the accompanying drawing in which:

Fig. 1 is a' vertical section diagrammatically illustrating the application of my improved iilling valve to a conventional type press; and

Fig. 2 is an enlarged vertical sectign through.,

my improved valve. Y

In the particular embodiment of the invention such as is disclosed herein merely for the purpose of illustrating one specific form among possible others that the invention might take in practice, I have diagrammatically shown in Fig. l a press having a base I, and an upper stationary crosshead 2 suitably supported by the base I by tie rods or framework 3. A platen 4 is normally moved downward by a ram and cylinder 5 and 6 while a pair of pushback cylinders 1 and 8 is connected to platen 4 in any suitable manner such as by piston rods 9. The cylinders 1 and 8 and the pistons therefor broadly constitute a return mechanism for the movable platen. The platen 4 and ramv 5 are adapted to initially move down- 5 ward under gravity until the work piece is engaged. During such gravity movement, iiuid from a. illling tank II! flows freely through ports IIa and into cylinder Ii past a check valve II in amanner such as is well understood in the art. 10

My improved means for operating and controlling the filling check valve Il will lhe understood more easily by describing the same in connection with the following sequence of press operations.

The platen 4 is held up by placing a reversing valve I2 in its down position whereupon iiuid pressure is discharged from a pump I3 through a check valve I4 and pipes I5 and I6 to the lower ends of pushback cylinders 1 and 8. At the 20 same time pump pressure is transmitted through a pipe I1 and a manually adjustable valve I8 to a port I9 of a pilot cylinder 29. the port I9 being -closed at this moment by reason of lling valve being in its down open position as will be ex- 25 plained later. Hence full pump pressure is built .up in the pushback cylinders to hold up the platen. `The platen could also be held up by placing the reversing valve in neutral thereby trapping iiuid in the pushback cylinders. A pipe 30 I3a supplies makeup iluid from lling tank I0 to pump I3.

To start the press down, reversing valve I2 is moved to its uppermost position, whereupon the pump is connected to a pipe 2| leading 'to the 35 main cylinder 6 while pipe I5 `is connectedv to a pump suction pipe 22. With these connections made, and the illling valve II already open as a free ilow check valve during down movement of main ram 5, lling fluid ows to cylinder 6 from 40 tank I0, but when platen 4 engages the work and resistance to movement occurs, then spring 39 moves lling valve I I to its closed position whereupon pump pressure transmitted through pipe 2l will build up in main cylinder 6 to act against the 45 under side of lllng valve I I to positively hold the valve closed. Hence the final stroke of the main ram is completed under full working pump pressure.

To reverse the ram, valve I2 is moved`to its 50 down position, whereupon pump I3 is `connected to pipes I5, I9 and I1. Fluid transmitted through pipe I1 and pilot cylinder port I9, ows into an annular recess 23 of a pilot piston 28 which is t now in its upper position by virtue of the lling 55 filling valve I I into lling tank I0.

valve having been' previously raised to its closed position. The fluid thence flows, Fig. 2, into ports 24, 25 and 26 to a chamber 21 containing the pilot piston 28 in which said ports and recesses are formed. Communicating with the annular recess 23 is a lateral passage 32 having a pressure control or bypass oriiice 29 in constant communication with the filling tank. I8. As a result of orifice 29, it is seen that pressure in pipes I1 and I6 and in the pushback cylinders 1 and 8 is maintained at a certain definite minimum value which is not great enough to move the -pushback rams together with platen 4 and main ram upwardly, although this pressure is great enough when acting on the top of differential piston 28 to move the same downwardly and thereby move a valve stem 30 vand the valve I I to an open position. When the lling valve is thus opened initially, 'the fluid in main cylinder 6 discharges into filling tank Il). The minimum pressure acting on the pushback rams 9 will create a force acting upwardly through these rams and main ram 5 so as to tend to generate pressure in the main cylinder, but said minimum pressure is sufficiently low that no appreciable pressure will be generated in the main ram cylinder 6 and hence the pressure therein offers very little resistance to opening movement of the lling valve by the pilot piston 28. During further opening movement of iilling valve II, annular lrecess 23 rides past bypass passage 32 thereby preventing escape of pump fluid through orice 29. Pump pressure will now build up to a maximum to cause the pushback mechanism to raise platen 4 and main ram 5, it being understood that during such upward movement fluid in main cylnders6 is freely discharged upwardly through To stop the press in its up position, valve I2 is moved by the operator to its down position and left therein. A subsequent down stroke cycle of the platen is effected in the manner as heretofore described.

Another advantage of my improved arrangement is that opening movement of the lling ./alve is automatically brought to a stop by a gradual deceleration without the necessity of relying upon a mechanical stop as has been the practice heretofore. To accomplish this retardation, it will be noted that downward movement of piston 28 will cause annular recess 23 to ride past port I9 and thereby gradually restrict and finally prevent flow of operating fluid to chamber 21, thereby bringing piston 28 and valve II to a complete stop.

However, it is necessary to relieve pressure in chamber 21 so that upon starting the succeeding down stroke the filling valve'will be able to close when the main ram is subjected to the full pump pressure to effect iinal movement of the main ram. The reduction of pressure in chamber 21 is accomplished by the provision of a check valve 33 adapted to allow iiow of iiuid to pipe I1 and thence through pipes I5 and 22 to the suction side of pump I3 when the reversing valve I2 is moved to its upperposition for effecting a down stroke. It will, of course, be understood that a usual spring 39 is employed to yieldably urge the filling valve toward its closed position upon release of pressure in chamber 21, although spring 39 is not strong enough during the initial down stroke of the main ram 5 to prevent automatic opening of the iilling valve by the suction action in main cylinder 6 caused by the down movement of ram 5 and its platen 4 under the action of gravity.

From the foregoing disclosure, it is seen that with my improved pilot piston and cylinder construction part of the pump discharge is bypassed through thel smallY orifice 29 directly into the filling tank I0 so that just suicient pressure will be present in chamber 21 on top of piston 28 to open check valve II, which pressure, however, is insuflicient to lift the press. As a result, no pressure can build up in the pushback line until the .filling check valve II has partially opened and closed oi port I9 together with the pump line connected thereto. When this occurs, pump pressure will build up in the pushback line to raise the press. Also'when the check valve II is about three-quarters open, the annular recess 23 will be moving past supply port I9 to cut off the pressure connection with consequent slowing down of the opening speed of the check valve to a very slow movement before coming to a stop,

l thus eliminating any possibility of shock.

Hence it is seen that I have provided a very eiiective filling check valve and control system therefor that is relatively simple and economical I in construction, operation and maintenance and in addition avoids the objections of hydraulic and mechanical shocks.

It will of course be understood that various changes in details of construction and arrangement of parts may be made by those skilled in the art without departing from the spirit of the Ainvention as set forth in the appended claims.

1. The combination in a hydraulic press comprising a main ram and cylinder and a return ram cylinder mechanism, a filling tank, a filling valve for controlling communication between said tank and said main cylinder, means constituting a source of iiuid pressure for operating said main raml and said return mechanism, operating means for opening said filling valve, and means responsive to opening of the filling valve for thereafter automatically initiating return movement of the main ram.

2. The combination in a hydraulic press comprising a main ram and cylinder and a return .ram and cylinder mechanism, a filling tank, a

filling valve for controlling communication between said tank and said main cylinder, iluid pressure means for operating said filling valve, means constituting a source of iiuid pressure for operating said main ram and said return mechanism, means for supplying fluid pressure from said source to said return mechanism and to said filling valve operating means, means for controlling said pressure so that it is insuiiicient to cause the return mechanism to raise the main ram but is suflicient to initially open the filling valve, thereby to discharge fluid under a relatively low pressure in said main cylinder to said filling tank, and means responsive to opening of the lling valve for automatically further controlling said pressure so that it is suiiicient to effect return operation of said return mechanism.

3. The combination in a hydraulic press comprising a main ram and cylinder and a return ram and cylinder mechanism, a iilling tank, a filling valve for controlling communication between said tank'and said main cylinder, means constituting a source of fluid pressure for operating said main ram and said return mechanism, a pilot piston and cylinder for operating said lling valve, means for supplying fluid from said source to said pilot cylinder, means for by-passing fluid from said source to maintain a predetermined minimum pressure in said pilot cylinder to effect initial opening thereof, and means responsive to opening of the filling valve to control said bypassing means and thereby cause the pressure of said fluid to increase suiciently to 5 operate said return mechanismf'-,

4. The combination in a hydraulic press comprising a main ram'and cylinder and a return ram and cylinder mechanism, a filling tank, a filling valve for controlling communication 'between said tank and said main cylinder, means constituting a source of fiuid pressure for operating said main ram and said return mechanism, means for opening said filling valve by fluid pressure supplied from said source, and means for reducing the rate of supply of fiuid from said source to said opening means for said filling valve automatically as the filling valve moves toward its open position thereby allowing the source of pressure to increase so that thereupon mi the return mechanism is operative.

5. The combination in a hydraulic press comprising a main ram and cylinder and a return ram and cylinder mechanism, a filling tank, a filling valve for controlling communication between said tank and said main cylinder, means constituting a source of fluid pressure for operating said main' ram and said return mechanism,

means for opening said lling valve by fluid pressure supplied from said source, and means automatically responsive to opening movement of said filling valve for gradually reducing the supply of fluid to said opening means thereby to retard opening movement of said filling valve as it progresses toward its open position.

at 6. 'I'he combination in a hydraulic press comprising a main ram and cylinder and a return ram and cylinder mechanism, a filling tank, a

filling valve for controlling communication between said tank and said main cylinder, means 40 constituting a source of fluid pressure for oper ating said main ram and said return mechanism, operating means "for opening said filling valve with fluid pressure from said source andl before such pressure is sufficient in the return 4,5 mechanism to initiate return movement of the main ram, and means responsive to opening of the filling valve for controlling the uid pressure to said opening means and thereby automatically allowing the pressure from said source to build up sufficiently to effect operation of the return mechanism and means for relieving the ud pressure in said filling valve operating means automatically when uid pressure in said return mechanism is relieved to permit initial down movement of the main ram.

7. The combination in a hydraulic press comprising a main ram and cylinder and a return ram and cylinder mechanism, a filling tank, a filling valve for controlling -communication between said tank and said main cylinder, means constituting a source of fluid pressure for operating said main ram and said return mechanism, a pilot piston and cylinder for opening said filling valve, a supply port in said pilot cylinder and a passage in said pilot piston adapted to register with said supply port and to transmit fluid pressure therefrom to said pilot cylinder, means for supplying uid pressure from said source to said port and to said return movement, a by-pass orifice communicating with said source of pressure to establish a pressure above a predetermined minimum in the pilot cylinder sufiicient to open said filling valve but insufficient to effect return movement of said return mechanism, and means automatically operative only after saidfilling valve is definitely open to thereafter control said orifice so as to allow said source pressure to build up to produce a force sufficient for return movement.

8. The combination in a hydraulic press comprising a main ram and cylinder and a return ram and cylinder mechanism, a filling tank, a filling valve for controlling communication between said tank and said main cylinder, means constituting a source of fluid pressure for operating said main ram and said return mechanism, a pilot piston and cylinder for opening said filling valve, a supply port in said pilot cylinder and a passage in said pilot piston adapted to register with said supply port and to transmit fluid pressure therefrom to said pilot cylinder, means for supplying fiuid pressure from said source to said port, and an orifice in said pilot cylinder wall adapted for communication with said pilot piston passage so as to maintain a pressure above a predetermined minimum in said pilot cylinder, said orifice and piston passage being so related that the orifice is closed ofi upon a predetermined movement of the piston thereby to permit the fluid pressure at said source to build up and effect final opening movement of the filling valve.

RICHARD W. DINZL.

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