US2516924A

US2516924A - Press operating valve with rapid advance and full pressure positions

Info

Publication number: US2516924A
Application number: US15534A
Authority: US
Inventors: Robert K Sedgwiek
Original assignee: American Steel Foundries
Current assignee: American Steel Foundries
Priority date: 1948-03-18
Filing date: 1948-03-18
Publication date: 1950-08-01
Anticipated expiration: 1967-08-01

Description

Aug. 1, 1950 INVENTOR Y ROBERT K. SEDGWIGK B VANCE AND ITIONS POS l8 Filed March FULL PRESSURE mm: mm 4 5 we: 2 E

amhnmz R. K. SEDGWICK PRESS OPERATING VALVE WITH RAPID AD Mum m 8 mm ATTORNEY Patented Aug. 1, 1950 UNITED STATES PATENT OFFICE PRESS OPERATING VALVE WITH RAPID AD- VANCE AN D FULL PRESSURE POSITION S.

Robert K. Sedgwick, Oak Park, Ill., assignor to American Steel Foundries, Chicago, 111., a corporation of New Jersey Application March 1a, 1948, Serial No. 15,534

7 Claims.

chamber 12 receiving a pipeor tube !4 carried by the casting 2 and slidably fitted in the ram at [6 in substantially fluid-tight engagement there with. Supported by the casting is a tank or reservoir [8 adapted to contain low pressure fluid communicating with the chamber 8 on the rapid adit is frequently desirable to incorporate what is known in the art as a speed change control to slow the advance stroke of the hydraulic motor before the resistance of the work is encountered and to thereafter initiate the full pressure stroke of the motor against the work. In prior art arrangements, many control mechanisms have been introduced for this purpose and usually involve multiplicity of valves and complicated piping arrangements.

Accordingly, it is a primary object of the present invention to device a single operating valve capable of controlling the rapid advance and pullback strokes of the motor and also capable of effecting speed change control for the purpose above described.

A further object of the invention is to devise a valve, such as above described, incorporating novel means for throttling the discharge of hydraulic fluid from the prefill valve of the hydraulic motor as the pullback phase of the motors cycle is initiated. By this means, sudden opening of the prcfill valve means and consequent noise and damage to the equipment is prevented.

The foregoing and other objects and advantages of the invention will become apparent from a consideration of the following specification and the accompanying drawing, wherein:

Figure 1 is a diagrammatic view of an hydraulic press incorporating the novel circuit, portions of the structure being broken away in vertical cross section to clarify the illustration;

Figure 2 is an enlarged vertical cross sectional view taken on the longitudinal axis of the operating valve with the stem thereof shown in elevation; and

Figure 3 is a cross sectional view taken on the line 3-3 of Figure 2.

Describing the invention in detail and referring first to Figure 1, the press comprises a cylinder casting 2 and a ram 4 having a head 5 defining a main advance chamber 8 and a return or pullback chambcr [0 Within the casting. I The ram 4 is hollow and comprises an internal rapid advance Vance stroke and the pullback stroke of the ram and cut off from communication with the main advance chamber 8 on the iull pressure stroke of the ram by aprefill valve Zllincluding a casin 22 with ports 23 connected to the reservoir. The

casing contains a stem 24 spring-pressed to its,

open position by a spring 28 reacting against the casing 22 and a spring seat 30 connected to the stem.

h ycle of the press is controlled by a single operating valve, generally designated 352, and shown in detail in Figures 2 and 3, wherein it will be seen that the valve comprisesa body or casing 34 havin a longitudinal here or passage 36 contaming a hollow s em 38 havin four 511001 or lands 2, 4 nd 46 and lso having a longitudinal passage 48 connected to the bore 36 y ports 50, 52, 54 and 56 through the respective lands of the stem,

The body 34 comprises an annular prefill chamber 58, a prefill exhaust or throttle chamber 60, a air of main exhaust ehambers E2 and $4, a rapid advance chamber 66, an inlet or. hi h pressure delivery chamber 58 and a pullback chamber 10. 1

The prefill exhaust chamber 5'! isconnccted directly to the tank by a port 12, as best scenin Figure and he exhaust chambers 62 nd 64 a similarly connected to the tank by ports (not shown). The nds of the bore 36 are connected to the tanks by ports 13.

The inlet chamber 68 is connected by a port 14 (Figure 2) to a pump 16. (Fi ure 1) operated by a motor 18, the suction side oithe ump being connected by a line to the tank It. V

The prefill chamber 58 is connected by a line 82 to the top of the casing 22 above the stem 24 and is connected through a conventionalspring pressed check valve 4 to the main chamber 8 of the hydraulic motor.

The r pid advance chamber 66 of the valve 32 is connected by a line 88 to the tube It and the pullback chamb r 0 of the valve is onne d y a line so to the pullback chamber ill of the bio draulic motor.

As indicated in Figure 1, the valve 32 is prefer.- ably actuated by pneumatic motors 921 and 94;; however, the valve m y be a uated ma ua or in any other desiredmanner, T e motor, 92

in Figure 2, the pressure fluid from the pump 16 is delivered to the inlet chamber 88 and flows through the port 54 and the passage 48 into the ports 52 and 5G and thence to exhaust through the chambers 62 and 54. Under these conditions, the prefill valve casing 22 is exhausted through the line 82, the prefill valve chamber 58 and the prefill exhaust valve chamber 66 inasmuch as the spool or land 40 of the stem 38, as best seen in Figure 2, accommodates flow of fluid from the chamber 58 to the chamber (iii.

The stem 38 is actuated to rapid advance position, indicated at the right extremity of Figure 2, by the motor 92 and, in this position of the stem, fluid is delivered from the inlet chamber '68 to the rapid advance chamber 66 and the pullback chamber It is exhausted through the exhaust chamber 64. Under these conditions the prefill valve chamber 58 is closed by the prefill land or spool 40.

In the full pressure stroke of the stem 33, indicated at the right of Figure 2, fluid from the inlet chamber 68 is delivered. to the rapid advance chamber 66 and thence into the ports 52 which, under these conditions, overlap the chamber 66. The fluid flowing into the ports 52 is conveyed through the passage 48 and the ports 50 into the prefill valve chamber .58 inasmuch as the ports 50, under these conditions, are disposed within the latter chamber. Thus fluid is conveyed to the line 82 (Figure 1) into the casing 22 acting upon the top area of the preflll valve stem 24 to urge the latter to its closed position. The fluid then flows through the check valve 84 which is adapted to create a slight back pros sure to close the stem 24 before delivery of fluid through the line 82 to the main advance chamber 8. Under these conditions, pressure is developed against the full cross sectional area of the head 6 on the full pressure stroke of the-ram 4. It may be noted in this connection that closing of the prefill valve stem 24 checks the rapid advance stroke of the ram 4 prior to initiation 4 of the pullback stroke, the stem is actuated by the motor 94 to the neutral position shown in Figure 2 preparatory to initiation of a new cycle.

It will be understood that the valve 32 may be actuated by manually operated means or may be automatically actuated by any suitable position or pressure responsive means, such" as are well known in the art. t will be understood that I do not wish to be limited by the exact embodiment of the device shown which is merely by way of illustration and not limitation as various and other forms of the device will, of course, be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

I claim:

1. In an hydraulic actuating circuit for an hydraulic motor having main advance and pullback chambers, ram means presenting main. advance and pullback areas in respective chambers and presenting a rapid advance area spaced from, the first-mentioned areas, a reservoir. of low.

pressure hydraulic fluid, and prefill valve meansadapted in the openposition thereof to'connect communication between said reservoir and said,

main advance chamber, said prefill valve means,

i comprising a closing pressure area adapted. when of the full pressure stroke thereof against the work. I

In the pullback or reverse position of the stem 38, as indicated at the right of Figure 2, pressure fluid is delivered from the inlet chamber 68 to the pullback'chamber I0 and is exhausted from the rapid advance chamberiifi to the exhaust chamber 62. At the same time, the prefill valve chamber 58 is exhausted at a predetermined rate through the port 12. This rate is determined by a throttle screw 95 threaded into the body 34 and held in adjusted position in the port 12 by alock nut 98. The outer end of the screw is provided with a cap nut I00 protecting a square extremity "12 of the screw adapted for actuation by a suitable tool, such as a wrench.

Thus due to the throttlingof fluid exhausted through the port 12, the prefill valve gradually opens at an adjustable predetermined rate preventing shock to the tank as the ram is actuated on the return or pullback stroke thereof by delivery of pressure fluid fromthe valve pullback chamber 10 through the line 90 to the pullback chamber In of the hydraulicmotor. At the end acted upon by pressure fluid to close said prefill valve means: .the combination, of an operating: valve including a body with an internal bore having a prefill chamber, a-preflllexhaust cham -a chamber, a pressure inlet chamber, a pullback chamber, and another main exhaust chamber. spaced in the foregoing sequence along said bore,

said exhaust chambersbeing connected to saidreservoir, said prefill chamber being connected to:

a port of said prefill valve means containing the closing area thereof and also being connected to.

saidmainadvance chamber through onewa vcheck valve means for accommodating flowmof fluid. to themain advance chamber after a predetermined back pressure has-been built up against said prefill valve area, a connection be tween the rapid advance chamber and the rapid advance area, and a connection between. said,

pullback chambers, a stem comprising a plurality of lands slidably fitted in said bore, said stern. being so formed and arranged that in the neutral position thereof one of said lands accommodates flow of fluid from the prefill chamber to the pre fill exhaust chamber, the other exhaust :cham bers and the inlet chamber being covered by the other lands respectively,passage means through said stem extending through all of said. lands and adapted in the neutral, position of the stem tooonnect the inlet chamber to the main exhaust chambers, said stem being adapted inthe rapidadvance position thereof to close the prefill. chamber, to direct flow of fluid from the inlet chamber to the rapid advance chamber and to exhaust flow of fluid from the pullback chamber to said, other main exhaust chamber, said stem being adapted in the full pressure position thereof to direct flow of. fluid from the inlet chamber to the rapid advance chamber, to direct fluid from the rapid advance chamber through said passage means to the prefillchamber and to exhaust the pullback chamber. to said other main exhaust chamber, and said stem. being. adapted in the reverse position thereof to direct flow of fluid from the inlet chamber tothe pull back"chamber, toexhaiis't "the "rapid advises chamber to said one main exhaust chamber and to exhaust the prefill chamber to the prefill exhaust chamber, and a source of high pressur fluid connected to the inlet chamber.

2. A circuit, according to claim 1, wherein said body is provided with means for adjustably throttling flow of fluid from the prefill exhaust chamber tothe reservoirs i "3. An operating valve for delivering pressure fluid comprising a body withan internal bore having a prefill chamber, a prefill exhaust chamber, a main exhaust chamber, a rapid advance chamber, a pressure inlet chamber, a pullback chamher, and another main exhaust chamber spaced in the foregoing sequence along said bore, a stem comprising a prefill land, aninlet land,'and a pair of exhaust lands slidably fitted insaid bore, said stem being so formed and arranged that in the neutral position thereof said prefillland accommodates flow of fluidfrom the" prefill chamber to the prefill exhaust chamber, the'other exhaust chambers and the inlet chamber being covered by the exhaust lands and the inlet land respectively, passage means through said stem having ports extending throughrespective lands and otherwise spaced fromsaid bore, said passage means being adapted in the neutral position of said stem to connect the inlet chamber to the main exhaust chambers, saidstembeing so formed and arranged that in the rapid advance position thereof said prefill land closes said prefill chamber positively preventing flow of fluid therethrough while the inlet land and one exhaust land accommodate flow of fluid fromthe inlet chamber to the rapid advance chamber and the other exhaust land accommodates flow of fluid from the pullback chamber to the exhaust chamber, said stem being so formed and arranged that in the full pressure position thereof the ports in said one exhaust land overlap the rapid advance chamber and the ports in the prefill land communicate with the prefill chamber, said one exhaust land accommodating flow of fluid from the inlet chamber to the rapid advance chamber and said other exhaust land accommodating flow of fluid from the pullback chamber to said other exhaust chamber, and said stem being so formed and arranged that in the reverse position thereof the inlet land and said other exhaust land accommodate flow of fluid from the inlet chamber to the pullback chamber and said one exhaust land accommodates fiow of fluid from the rapid advance chamber to the first-mentioned exhaust chamber and the prefill land accommodates flow of fluid from the prefill chamber to the prefill exhaust chamber.

4. A valve, according to claim 3, wherein said body is provided with means for adjustably throttling flow of fluid from the prefill exhaust chamber.

5. A valve comprising a body with an internal bore having seven chambers, a stem in said bore having four lands slidably fitted within the bore, the stem being so formed and arranged that in the neutral position thereof the first land accommodates fiow of fluid between the first and second chambers while the second, third and fourth lands cover the third, fifth and seventh chambers respectively, a passage through said stem having ports connected to each land, the ports in the second, third and fourth lands being disposed within chambers covered thereby in the neutral position of the stem while the ports in the first land are spaced from the first chamber, said stem being so formed and arranged that in a first advance position thereof the third land accommodates fiow'of fluid between the fourth and fifth chambers and the fourth land accommodates flow of fluid between the sixth and seventh chambers and the second land accommodates flow of, fluid between the second and third chambers, the first chamber being blocked by the first land and all ports being blocked by engagement with the bore, said stem being so formed and arranged that in a second advance position thereof the ports in the first land are disposed within the first chamber and the, ports in the second land overlap the fourth chamber to accommodate flow of fluid between the fourth and fifth chambers andthrough the passage to the first chamber, the fourth land accommodating flow of fluid between the sixth and seventh chambers, and said stem being soformed and arranged that in a reverse position thereof the first and second lands accommodate flow of fluid between the first and second chambers, the second and third lands accommodate flow of fluid between the third and fourth chambers and the third and fourth lands accommodate flow of fluid between the fifth and sixth chambers, all of the ports being blocked by engagementwith the bore, a port connected to each chamber, and means for adjustably throttling flow of fluid through the port of the second chamber. a i i i l 6. A. valve comprising a body with an internal bore havingseven chambers, a stem in said bore having four lands slidablyifitted within the bore, the stem being so formed and arranged that in the neutral position thereof the first land accommodates flow of 'fluid betweenthe first and second chambers while the second, third and fourth lands cover the third, fifth and seventh chambers respectively, a passage through said stem having ports connected to each land, the ports in the second, third and fourth lands being disposed within chambers covered thereby in the neutral position of the stem while the ports in the first land are spaced from the first chamber, said stem being so formed and arranged that in a first advance position thereof the third land accommodates flow of fluid between the fourth and fifth chambers and the fourth land accommodates flow of fluid between the sixth and seventh chambers, the first chamber being blocked by the first land and all ports being blocked by engagement with the bore, said stem being so formed and arranged that in a second advance position thereof the ports in the first land are disposed within the first chamber and the ports in the second land overlap the fourth chamber to accommodate flow of fluid between the fourth and fifth chambers and through the passage to the first chamber, the fourth land accommodating flow of fluid between the sixth and seventh chambers, and said stem being so formed and arranged that in the reverse position thereof the first and second lands accommodate flow of fluid between the first and second chambers, the second and third lands accommodate flow of fluid between the third and fourth chambers and the third and fourth lands accommodate fiow of fluid between the fifth and sixth chambers, all of the ports being blocked by engagement with the bore,

7. In an hydraulic actuating circuit for an hydraulic motor having main advance and pullback chambers, ram means presenting main advance and pullback areas in respective chambers and presenting a rapid advance area spaced from the first-mentioned areas, a reservoir of low pressure hydraulic fluid, and prefill valve means 7 adapted in the open position thereof to connect said reservoir and said main advance chamber and adapted in the closed position to cut off communication between said reservoir and said main advance chamber, said prefill valve means comprising a closing pressure area adapted when acted upon by pressure fluid to close said prefill valve means; the combination of an operating valve including a body with an internal bore having a prefill chamber, a prefill exhaust chamber, a main exhaust chamber, a rapid advance chamber, a pressure inlet chamber, a pullback chamber, and another main exhaust chamber spaced in the foregoing sequence along said bore, said exhaust chambers being connected to said reservoir, said prefill chamber being connected to a port of said prefill valve means containing the closing area thereof and also being connected to said main advance chamber through one-way check valve means for accommodating flow of fluid to the main advance chamber after a predetermined back pressure has been built up against said prefill valve area, a connection between the rapid advance chamber and the rapid advance area, and a connection between said pullback chambers, a stem comprising a plurality of lands slidably fitted. in said bore, said stem being so formed and arranged that in the neutral position thereof one of said lands accommodates flow of fluid from the prefill chamber to the prefill exhaust chamber, the other exhaust chambers and the inlet chamber being covered by the other lands respectively, passage means through said stein extending through all of said lands and adapted in the neutral position of the stem to 8. connect the inlet chamber to the main exhaust chambers, said stem being adapted in the rapid advance position thereof to close the preflll chamber, to direct flow of fluid from the inlet chamber to the rapid advance chamber and to exhaust flow of fluid from the pullback chamber to said other main exhaust chamber, said stem being adapted in the full pressure position thereof to direct flow of fluid from the inlet chamber to the rapid advance chamber, to direct fluid from the rapid advance chamber through said passage means to the prefill chamber and to exhaust the pullback chamber to said other main exhaust chamber, and said stem being adapted in the reverse position thereof to direct flow of fluid from the inlet chamber to the pullback chamber, to exhaust the rapid advance chamber to said one main exhaust chamber and to exhaust the prefill chamber to the prefill exhaust chamber, and a source of high pressure fluid connected to the inlet chamber, the ends of said bore having ports connected to said reservoir.

ROBERT K. SEDGWICK.

REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PATENTS Number I Name Date 226,218 Wilson Apr. 6, 1880 1,780,471 Galloway et a1. Nov. 4, 1930 2,004,399 Svenson June 11, 1935 2,048,789 Fiegel et a1 July 28, 1936