US1859058A - Press system - Google Patents

Description

May 17, 1932. T, F. sTAcY 1,859,058

PRESS SYSTEM Filed Jan. 7,1930 2 sheets-sheet 1 df'llevw:

TEW l\ a May 17, 1932. STACY 1,859,058

PRESS SYSTEM Filed Jan. 7, 1930 2 Sheets-Sheet 2 Patented May 17, 1932 UNITED STATES PATENT OFFICE THOMAS F. STACY, OF PIQUA, OHIO, ASSIGNOR TO THE FRENCH OIL MILL MACHINERY CO., OF PIQUA, OHIO PRESS SYSTEM Application led January 7, 1930. Serial No. 419,095.

This invention relates to hydraulic presses, and particularly to a system for the operation of such presses.

An object of the invention is to provide an f improved apparatus for. the operation of hydraulic pressesy which will be economical in the use of high pressure fluids, which will be exceptionally rapid in operation, which will be as automatic and uiet as possible in operation, and Which will be relatively simple, compact and inexpensive.

,Various other objects and advantages will bc apparent from the following description of an embodiment of the invention, and the novel features will be pointed out herein4 after in the appended claims.

In the accompanying drawings:

Fig. 1 represents, somewhat schematically and diagrammatically, a press operation system constructed in accordance with this invention;

Fig. 2 is a sectional elevation through the check valve casing on a larger scale to illustrate the details thereof Fig. 3 is a sectional plan of one of the valves of the same, the section being taken approximately along the line 3-3 of Fig. 2; an

F ig. 4 is a diagram similar to Fig. 1 except that a pump is connected to opposite ends of the valve casing.

ln the embodiment of the invention, the hydraulic press may be of any suitable construction, and may include a movable pressure platen 1, a main piston or ram 2 reciprocating in 'a main cylinder 3, which piston 2 and cylinder 3 together form a main hydraulic pressure device by which the platen 1 may be subjected to very high hydraulic pressures and advanced to its Work or load. The platen 1 cooperates with another platen or base, not shown, as usual in the art.

A plurality of rods 4 connect the platen 1 to a cross bar or beam 5 which is connected to or carries an auxiliary or pull-back piston 6 that reciprocates in an auxiliary or pullback cylinder 7. The cylinder 7 may, for convenience, -be disposed endwise of or Iparallel to the cylinder 3, so that the pistons 2 and`6 extend in opposite directions toward one another and into their respective cylinders which are disposed endwise of one another between the pistons. The piston 6 and cylinder 7 together constitute an auxiliary or pull-back device by which the platen 1 vmay be retracted or returned to its normal or starting position.

A source of fluid under pressure is utilized in connection with this system, and for this purpose I have found that a closed or pneumatic tank 8 constitutes a very satisfactory and inexpensive source. This tank 8 is closed so as to confine a gas,such'as air, in its upper part and contains a liquid in its lower part. The gas in the upper part is placed under pressure and serves as pneumatic means by which pneumatic pressure is exerted on the liquid in the tank. lA main pipe 9 connects the lower end of the tank 8 with a valve casing l0. The valve casing has a passage 11 extending crosswise of the end of the pipe 9 which opens into the casing so that the liquid from thepipe 9 may enter the passage .11, divide and move toward opposite ends of the casing 10.

A pipe or conduit 12 is attached to one end of the casing 10, in communication with one end of the passage 11, and connects the passage 11 with the cylinder 7. Another' pipe or conduit 13, usually larger than the pipe 12, is connected to the other end of the casing 10, in communication with the opposite end of the passage 11, and connects the assage 11 to the main cylinder 3. It will Ee observed that liquid from the tank 8 may pass through the pipe 9 into the passage 11, and from the latter through both or either of the pipes 12 or 13 to the pull-back or main cylinders 7 or 3.

A reversible pump 14 is connected between the pipes 12 and 13, so as to transfer liquid between the two rams in either direction. When the transfer is in a direction from the pull-back cylinder to the main cylinder,- the main ram or piston 2 will be operated downwardly, and when the pump 14 is reversed, liquid will be withdrawn `from the 'main cylinder v3 and directed to the Vpull-back. cylinder y.to cause a retraction or elevation of the platen 1.

A valve seat ring 15 is provided in one end of the passage 11 between the connections to the pipes 9 and 13, and a similar but preferably smaller valve seat ring 16 is provided at the opposite end of the passage 11 between the points of communication of the passage 11 with the pipes 9 and 12. The Outer ends of the passage 11 may be closed by removable plugs 17 provided in the casing ends and having recesses 18 in their inner ends. A valve 19 is provided in the outer end of the passage 11 beyond the seat ring 15, and cooperates with the ring 15 to close or open communication between the pipes 9 and 13. To guide the valve 19 toward and from seating position upon the ring 15, the valve may have a piston or extension 20 which slides in the cavity 18 in the adjacent plug 17.

In order to avoid interference with the free operation of the valve 19, by suction in the inner end of the recess or cavity 18, a hole 21 may be drilled from the outer or free end of the piston or extension 20 towards the valve 19 and then one or more transverse holes 22 may be drilled through the piston or extension 20 adjacent the valve 19 and communicating with the hole 21. This provides free communication between the pipe 13 and the recess 18 so that the piston 20 may slide freely and guide the Valve 19 toward and from its seat. The valve 19 is thus a freely opening check valve which permits free HOW of liquid from the pipe 9 to the pipe 13, and automatically prevents return How because the return flow causes a seating of the valve 19.

A similar and preferably smaller valve 23 is disposed in the opposite end of the passage 11 between the seat ring 16 and the pipe 12, and this valve 23 is similarly guided toward and from the ring 16 by a piston or extension 24.- of the valve, this piston or extension 211- being provided with longitudinal and crosswise holes 21 and 22 as in the piston eXtension 20. The valve 23 thus also is a freely opening check valve controlling communication between the pipes 9 and 12, permitting free flow from the pipe 9 to pipe 12 and automat-ically checking reverse flow.

It is undesirable that both check valves be closed at the same time, and therefore one of the valves, such asthe valve 23, is provided with a stem 25 extending through the ring 16 in spaced relation thereto along the passage 11 into the ring 15. The stem 25 is of such length that when the valve 23 is in closed position on its seat ring 16, the stem will project beyond the ring 15 and prevent closing movement of the valve 19. When either valve moves into open position it will permit movement of the other valve 23 into closed position. Thus each of the valves 19 and 23 is free to move to open position independently of the other valve, yet the simultaneous closing of both valves is automatically prevented.

In the operation of this system the tank 8 is partially filled with gas, such as air, and the balance with a liquid of the type, such as oil, used for the operation of hydraulic presses, the main ram 2 being retracted, for example, as shown in Fig. 1. At this time the gas or air in the tank 8, is under considerable pressure. To cause an operation of the press, the pump 14 is operated in a direction to draw liquid from the pipe 12 and the pull-back cylinder 7 and force it into the pipe 1,3 from which it travels to the main cylinder 3. At this time there is no great pressure in the cylinder 3, and the valve 19 will immediately be opened by reason of the pressure in the tank or reservoir 8, and the liquid will then pass through pipes 9 and 13 into the main press cylinder 3, causing the ram 2 to travel downwardly rather rapidly.

The ram 2, under the pressure from tank 8, travels Jfaster than it could by the action of the pump alone, and the liquid in the pullback ram is displaced faster than it can be handled by the pump. This displaced liquid tends to flow through the pipe 12 into passage 11, and consequently tends to close the other valve 23. The operaton of the ram 2 continues until it engages the work and the resistance of the work Causes a building up of pressure in the cylinder 3 which approximately equals the pressure in the tank 8. When the pressures in the cylinder 3 and tank 8 approximately equalize, the valve 19 will close because the flow therethrough Jfrom the pipe 9 will stop and the continued operation of the pump 14 will build up a pressure in the pipe 13 tending to cause a reverse flow to the pipe 9. This reverse liow automatically closes the valve 19.

The displacement of liquid from the pullback cylinder 7 will decrease upon slowing up of the platen 1, and to supply the suction side of the pump, the liquid will iiow from the pipe 9 through the valve ring 16 into the pipe 12 causing an opening of the valve 23. The pump, Jfor an instant, may tend to discharge backwardly through the valve ring 15 because the valve 23 may open slightly before the increased pressure in pipe 13 Causes a closing of the valve 19. When the valve 23 opens, however, it allows the valve 19 to close and the pump will then build up a pressure in the main cylinder to the desired point. i

When a reverse operation of the press is desired, the direction of the operation of the pump is reversed so as to draw liquid from the pipe 13 and cylinder 3 and dscharge it into the pull-back cylinder 7. At the beginning of this operation, the suction in the pipe 13 transmitted from the pump will cause the pressure in the pipe 13 to drop rapidly to zero and the pump will discharge into the pipe 12, some of the liquid passing into the'cylinder 7 and the remainder into the pipe 9 and thence into the tank 8.

As soon as the pressure in the main cylinder drops below that of the tank 8, or to approximately zero, the valve 19 will open due tothe pump suction on the pipe 13 and the air pressure on the other side. When the valve 19 opens for this reason, the other valve 23 may close, whereupon the pump will then discharge into the pull-back cylinder 7, pushing the piston 6 outwardly and reextent in the prior devices.

tracting the platen l and rain 2.

The valve 23 through its stem 25 holds the valve 19 open and the excess liquid from the cylinder 3 will flow through tlie pipe 13 into the pipe 9 and thence back into the tank 8 where the pressure is again built up and stored for a succeeding operation. This completes one cycle of operation and it will be noted that the press is controlled solely by the operation of the pump 14, all of the other operations occurringA autoniat'cally. The valve casing 10 may, if desired, be arranged in horizontal position so that the valves 19 and 23 will travel yhorizontally toward and from closed positions.

In Figs. 1 and 2, the pump 14 is connected directly across the pipes 12 and 13, but in Fig. 4 the pump 14 is connected by pipes 14a and 146 to the same pipes 12 and 13 through the opposite ends or plugs 17a of the valve housing or casing 10, so that the liquid entering the valve casing 10 from the pump 14 will strike one of the movable valves and tend to force it closed. The discharge from the pump travels through the holes 21 and 22 in the valves, and by impinging directly upon a valve will have its direction of flow changed somewhat, this change in direction providing the positive closing force acting upon the valve and tending to close it quickly` and without chattering. In addition to the avoidance of chattering and consequent noise, this rapid closing of the valve also saves time in the cycle of operations.

In this double check valve arrangement, in which the valves 19 and 23 operate one another automatically, there will be no hammering or knocking such as has existe-d to some While the two check valves might be connected permanent-- ly together it is not necessary to do so. The action is usually more sluggish when the two check valves are connected together than when separate, and it is easier to manufacture the check valves when they are formed of separate parts which are not connected.

While a pneumatic tank 8 has been illustrated for the purpose of providing a source of fluid under pressure, it vwill be understood that a weighted accumulator may be employed instead of the tank 8 itdesired, or

any other sources of fluid under pressure may be used.

It will be obvious that various changes in the details, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art Within the principle and scope of the invention as expressed in the appended claims.

Claims:

1. In a hydraulic press system, a main ram, an oppositely acting pull-back ram, a source of fluid under pressure connected to each of said rams, a check valve in each connection of said source to said rams and preventing return flow of said fluid from said rains toward said source, means for transferring fluid between said rams in either direction to vary ,the effectiveness of said rams alternately, and means interposed between said check valves, and preventing the seating of both valves at the same time.

2. In a hydraulic press system, a main ram, an oppositely acting pull-back ram, a source of fluid under pressure connected to each of said rams, a check valvein each connection of said source to said rams to permit free flow of said-fluid from said source towards said rams and automatically preventing return flow, the valve in the connection to said main rain being the larger of the valves, means for transferring fluid between said rams in either direction to vary the effectiveness of said rams alternately, and a stem carried by one of said valves and operative upon the other valve to prevent seatmediate of its ends to said pipe and having a passage extending transversely of the said pipe, conduits connecting the ends of said passage to said rams, said passage having outwardly facing valve seats between said pipe and said conduits, a check valve in the outer end of each passage cooperating with its adjacent valve seat, whereby said valves may open freely to permit flow of said fluid from said source to both rams and automatically prevent return fiow to said source, means for transferring fluid between said rams in either direction to vary the relative electiveness of said rams, and means interposed between said valves whereby the simultaneous closing of both valves is prevented and opening of either valve permits closing of the other.

4. In a hydraulic press system, a main ram, an oppositely acting pull-back ram, a source of fluid under pressure, a pipe leading from said source, a valve casing connected interz wardly facing valve seats between said pipe and said conduits, a check valve in the outer end of each passage cooperating with its adjacent valve seat, whereby said Valves may open freely to permit iiow of said fluid from said source to both rams and automatically prevent return flow to said source, means for transferring fluid between said rams in either direction to vary the relative effectiveness of said rams, one of said valves having a stem e): ending along said passage and engageable with the other valve to prevent simultaneous seating of both valves, whereby the opening of either valve willautomatically allow closing of the other valve.

5. In a hydraulic press system, a main ram, an oppositely acting pull-back ram, a source of fluid under pressure connected to each of said rams` a separate check valve in each connection of said source to said rams to permit free flow of said fluid from said source towards said rams and automatically preventing return How, and means for transferring fluid between said rams in either direction to vary the effectiveness of said rams alternately, said valves being operable upon one another to prevent closure of both valves at the same time, whereby openin of either valve automatically allows closing of the other.

6. In a hydraulic press system, a main ram, an oppositely acting pull-back ram, a source of fluid under pressure connected to each of said rams, a check valve in each connection of said source to said rams to permit free How of said fluid from said source towards said rams and automatically preventing return iiow, means interposed between said check valves, whereby the simultaneous closing of both valves is prevented, and the opening of either valve permits the closing of the other, and means for transferring fluid in either direction between said connections and discharging into said connections between the valves and the rams in a manner to impinge directly against a valve in a direction tending to close it when` the direction of flow is into the connection having that particular valve. whereby when the direction of fluid transfer is reversed, the valves will be forcibly actuated into a reverse relation to one another.

7. In a hydraulic press system, a main ram, an oppositely acting pull-back ram, a source of fluid under pressure connected to each of said rams, a check valve in each connection of said source to said rams to permit free flow of saidiiuid from said source towards said rams and automatically preventing return flow, one of said valves having a stem operative upon t-he other valve to prevent seating of both valves at the. same time, whereby when one valve opens it automatically allows closing of the other valve, and means for transferring fluid between said rams in either direction through said connections, with the discharge from the pump into either connection impinging directly upon a valve in that connection in a direction tending to close that valve, whereby, when the direction of operation of the pump is reversed the valves will be quickly and forcibly reversed automatically and without chattering.

8. In a hydraulic press system, a main ram, an oppositely acting pull-back ram, a source of fluid under pressure, a pipe leading from said source, a valve casing connected intermediate of its ends to said pipe and having a passage extending transversely of the said pipe, conduits connecting the ends of said passage to said rams, said passage having outwardly facing valve seats between said pipe and said conduits, a check valve in the outer end of each passage cooperating with its adjacent valve seat, whereby said valves may open freely to permit flow of said fluid from said source to both rams and automatically prevent return flow to said source, means interposed between said valves, whereby the opening of either valve automatically allows closing of the other valve, and a re versible pump connected to the outer ends of said passage for transferring fluid in either direction between said rams through said conduits.

9. In a hydraulic press system, a main ram, an oppositely acting pull-back ram, a source of fluid under pressure connected directly to each of said rams, a separate, free check valve in each connection from said source to said rams to permit free flow of said uid from said source toward said rams and automatically preventing return flow, and means for transferring fluidV between said rams in either direction to vary the effectiveness of said rams alternately, one of said valves having a part acting upon the other valve to prevent seating of both valves at the same time, whereby when one valve closes it automatically forces the other valve open.

10. In a ,hydraulic press system, a main ram, an oppositely acting pull-back ram, a

source of fluid under pressure, a pipe leading from said source, a valve casing connected to said pipe and having a` passage communicating between its ends with said pipe, conduits connecting the ends of said passage to said rams, sai-d passage having outwardly facing valve seats between said pipe and said conduits', a free check valve" in the outer end of each passage cooperating with the adjacent valve seat, whereby said valves may open freely to permit flow of said fluid from said source to both rams and automatically prevent return flow to said source, means connected to the opposite ends of said passage for transferring fluid between said conduits in either direction to vary the relative eectiveness of said rams, said means opening into the ends of said passage in the directions in which said valves move toward their seats, whereby astream of fluid discharged into either end of the passage from said transferring means will directly impinge upon the adjacent valve and .urge it into closed position.

11. In a hydraulic press system, a main ram, an oppositely acting pull-back ram, a source of fluid under pressure, a pipe lead ing from said source, a valve casing connected to said pipe and having a passage cornmunicating between its ends with said pipe, conduits connecting the ends of said passage to said rams, said passage having outwardly facing valve seats between said pipe and said conduits, a free check valve in the outer end of each passage cooperating with the adjacent valve seat, whereby said valves may open freely to permit flow of said fluid `from said source to both rams and automatically prevent return fiow to said source, means connected to the opposite ends of said passage for transferring fiuid between said conduits in either direction to vary the relative effectiveness of said rams, said means opening into the ends of said passage in the directions' in which said valves move toward their seats, whereby a stream of fluid discharged into 'either end of the passagev from said transferring means Will: directly impinge upon the adjacent valve and urge it into closed position, said valves having cooperating parts which prevent the seating of both valves at the same time.

THOMAS F. STACY.

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