US2839897A - Control valves for hydraulic presses - Google Patents

Control valves for hydraulic presses Download PDF

Info

Publication number
US2839897A
US2839897A US573971A US57397156A US2839897A US 2839897 A US2839897 A US 2839897A US 573971 A US573971 A US 573971A US 57397156 A US57397156 A US 57397156A US 2839897 A US2839897 A US 2839897A
Authority
US
United States
Prior art keywords
valve
pressure
connection
spindle
servo
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US573971A
Other languages
English (en)
Inventor
Towler Frank Hathorn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Electraulic Presses Ltd
Original Assignee
Electraulic Presses Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB922155A external-priority patent/GB812133A/en
Application filed by Electraulic Presses Ltd filed Critical Electraulic Presses Ltd
Application granted granted Critical
Publication of US2839897A publication Critical patent/US2839897A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J9/00—Forging presses
    • B21J9/10—Drives for forging presses
    • B21J9/12—Drives for forging presses operated by hydraulic or liquid pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J9/00—Forging presses
    • B21J9/10—Drives for forging presses
    • B21J9/20—Control devices specially adapted to forging presses not restricted to one of the preceding subgroups
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/16—Control arrangements for fluid-driven presses

Definitions

  • This invention relates to control valves for hydraulic presses and particularly for direct-hydraulic presses of the type in which the pressure liquid for the operating stroke and return stroke of the hydraulic press is directly supplied by hydraulic pumps without the interposition of a hydraulic accumulator. Nevertheless it will be understood that a hydraulic accumulator may be used for auxiliary operations or to operate the control valves.
  • this invention relates tocontrol valves for direct hydraulic forging and swaging presses in which it is desired to make a series of rapidly repeated short planishing strokes in addition to normal forging strokes.
  • the invention also relates to control valves for direct hydraulic presses for such operations as forging, coining, or forming, in which it is desired to secure almost instantaneous reversal :of the press ram upon completion of the pressing operation, or at a point controlled by the operator.
  • One object of this invention is to separate some of the primary pressure control valves from the pilot-pressure control valves, so that the primary-pressure valves may be mounted on or near their associated press cylinders thereby employing less large bore high pressure piping, and permitting most of the pilot-pressure valves to be mounted in a control panel conveniently located to suit the press operator.
  • a further object of this invention is to provide a directional control valve so constructed and arranged that the delivery of the primary pressure pumps does not pass through the said directional control valve to either the. press cylinder or return cylinders, and the said directional' control valve being soarranged that'the delivery of the primary pressure pumps is continuously connected to the return cylinders and the function of the new directional control valve is such as todirect pressure liquid to actuate admission valves to direct the delivery of the primary pressure pumps to the press cylinder for the forging stroke and alternately to actuate the prefill and exhaust valve for the return stroke.
  • a still further object of this invention is to provide a servo-actuated directional control valve of simple construction for the control of hydraulic forging presses and like'presses, the said control valve having only two operative positions, forwardfand return and for such valve to be servo-controlled by a simple reversingvalve.
  • Yet a further object of this invention is to arrange the servo-actuated directional control valve in a hydraulic system so that the primary pressure does not pass through the directional control valve to either the main cylinder or the return'cylinders but the said valve directs the primary pressure to actuate one or more admission valves to serve that purpose.
  • all the primary pressure pumps may be in continuous communication with the return cylinders and one function of the said directional control valve is to direct primary or servo pressure to actuate an admission valve so as to admit primary'pressure from all the pumps tothe main cylinder to effect the, forging stroke and another function of the said directional control valveis to direct primary pressure or servo pressure to actuate the prefilling and exhaust valve 'of' the press in order to release liquid from the ,main cylinder of the press to effect the return stroke of the press ram as the said admission valve is closed.
  • a further object of this invention is to provide improved means for regulating the length of the return stroke when making rapid planishing strokes on automatic cycle.
  • The. present invention consists broadly in a hydraulic system which comprises in combination with a hydraulic forging press having a main ram in a cylinder for effecting the forging stroke, one or more return rams and cylinders for effecting the return stroke of the main ram and a prefill and exhaust valve which is opened at the conclusion of the forging stroke to decompress the main cylinder and permit the main ram to make its return stroke, control means comprising two sets of primary pressure pumps which deliver directly to the one or more return rams and cylinders during the return stroke, a servo pressure liquid supply line having means for maintaining therein a supply of liquid at a predetermined pressure, an admission valve adapted to open automatically and pass the delivery of one set of pumps to themain press cylinder for a forging stroke of the press ram and to be closed by servo pressure to cause said set of pumps to deliver directly to the one or more return.
  • a servooperated reflux valve adapted to control the rate at which liquid is displaced from the one or more return cylinders during each forging stroke and to divert the same to the main press cylinder, servo pressure operated unloading valves for loading and unloading each set .of primary pressure pumps, a control valve which is manually operated to control the functions of the press and a'servo pressure operated distributing valve which operates under the control of the manually operable valve to distribute servopressure for eifecting operation of the servo pressure operated valves in the system and primary pressure for opening the prefill-' exhaust valve of the press.
  • the invention also includes a hydraulic systemas above in which, in the control means a reversing valve is emvalve when the press is operating to planishing strokes.
  • Fig. 1 is a diagrammatic arrangement of the system shown in conjunction with a downstroking forging press with the main control and distributing valves in the neutral position.
  • Figs; 2, 3 and 4 show the main control valve of Fig. l
  • Figs. 5 and 6 show the distributing valve of Fig. l
  • Fig. 1 The hydraulic systemillustrated in Fig. 1 isshown n conjunction with a downstroking forging press and in the figure A denotes the press cylinder and main ram,
  • B the returncylindcrs and rams for effecting the upward or return stroke of the main press ram
  • C the prefill exhaust valve to control the filling by gravity of oil from an. overhead tank Q
  • D a displacement piston and cylinder in which the displacement piston reciprocates .with the main press ram.
  • the control gear of the present invention forming the hydraulic system illustrated in Fig. .1 comprises'a servopressure operated distributing valve E, a hand or lever operated main control valve U incorporating a reversing valve, a stroke control valve V, a normally open pilot pressure operated relay valve L, a normally closed pilot pressure operated relay valve S, a pump W for supplying servo-pressure, two sets of pumps Y and Z for supplying primary pressure for actuating the press, normally .open servo operated amplifier valves J and K which control the loading and unloading of the sets of pumps Y .and Z respectively, a reflux valve H which among other purposes hereafter to bedescribed functions to regulate the speed of the approach stroke of the press ram, and
  • the system illustrated also includes a fixed pressure master valve R functioning as a relief valve to limit the pressure of the liquid delivered by the two sets of primary pressure pumps Y, Z, a relief valve I to limit the pressure of the liquid delivered by the low pressure servo pump W, and
  • variable pressurerelief valve T to limit the pressure within the press cylinder A.
  • a passage 11 is provided within the casing which connects- US to U3 and a longitudinalpassage i is formed within the; interior of the valve spindle. This passage i communicates at each end with the interior of the bore by radial holes so as, to on occasions provide a connection between U2 and outlet U6 which leads to exhaust.
  • the separate spindle c is formed with a miter valve c1 adapted to coact with a seating within the bore containing the spindle c, and to the lefthand of this miter valve a reduced portion c2 opposite to the radial passage or connection U7.
  • a small plunger j projecting from the left hand end of the spindle 0 extends into a space which receives primary pressure liquid through the radial passage or connection U8.
  • The. right hand end of the spindle c is also provided with a small diameter PIOJCC- tion k which on occasion is adapted to be contacted by the opposing end of the spindle a and when so contacted to preserve an annular space which is open to exhaust by means of the connection U9.
  • the head of the miter valve c1 is contained within an annular space which is connected to the connection U1 by means of a transfer passage 1 which although shown in the drawing as being on the exterior of the valve casing is in practice, formed within the thickness of the valve casing.
  • a further interior transfer passage m is provided connecting connection U9 to the space at the extreme left hand end of the valve spindle c.
  • Servo pressure operated directional control valve E The directional control valve B is operated by servo pressure under the control of the lever operated valve U .and as illustrated in the drawings its valve member is for actuating the prefill valve C.
  • the aforementioned openings or connections are indicated in the drawings by the numerals 1 to 12 and in this specification these are referred to as E1, E2, E3, E4, E5, E6, E7, E8, E9, E10, E11 and E12 respectively.
  • the shorter portion n of the valve member is separate from :the valve spindle 0 and its function is to act as a piston to force the spindle 0 to the right hand position in the drawing when the spindle of control valve U is moved by the operator into the hand reversal position shown in Fig. 5 of the drawings.
  • valve E As in the case of valve U some of the connections in valve E are interconnected by internal transfer passages and in the valve illustrated these include a transfer passage p connecting E5 to a space p1 at the right hand end of the valve spindle 0, a transfer passage q containing a choke ql in its length and connecting E1 to E11,
  • the spindle o is reciprocated to the right in the drawings by the admission of servo pressure through the connection 11 toan annular space between the two portions n and 0 of the valve member and to the left by the admission of servo pressure to the space p1 through the connection 5 and transfer passage 1 in which space it acts against the outer end of a small piston 01 forming an integral extension of the spindle 0.
  • This through passage also communicates with the cylinder 15 by a branch connection 17 containing a spring loaded check valve 18.
  • a piston 19 Freely reciprocable within the cylinder 15 and slidable over the spindle 10 is a piston 19. This piston is moved towards the right hand end of the cylinder 15 in the drawing by servo pressure delivered by the displacement ram D on the press through connection marked 2 on the drawings at the left hand end of the present valve V and the piston 19 is returned to the left hand end of its cylinder by servo pressure entering past the check valve 18 in the branch connection 17.
  • the relief valve T comprises a valve member 20 which is held closed by a spring whose tension is varied by a calibrated thimble nut'21.
  • the force applied by the press ram -A is limited to a figure which is predetermined by adjustment of the nut 21.
  • the left hand end of the valve member 20 is open to primary pressure through connection 1, hereafter referred to as T1 and when the predetermined pressure is exceeded the valve member 20 is forced to the right in the drawing until T1 connects with an outlet connection marked 5 and hereafter referred to as T 5.
  • T1 primary pressure from T1 passes out through T5 to connection E11 of distributing valve E and acts to force the valve spindle of this valve to the right in the drawing to bring about reversal of the press ram A.
  • the casing containing the spring of valve T is, permanently open to exhaust through connection marked 6.
  • the auxiliary apparatus shown in Fig. 1 includes:
  • a relief valve R designed to limit the pressure of the liquid delivered by the primary pumps Y, Z,
  • the press cylinder is filled from the overhead tank Q- through the prefill valve C, that is to say that the press cylinder draws liquid from tank Q through the prefill valve on the gravity downward stroke of the press ram and on the return stroke it returns pressure liquid. through the decompression valve into tank Q to decompress the press cylinder and, when the prefill valve is held open, liquid is returned to the tank Q on the upward or; return stroke of the press ram A.
  • the servopressure actuated directional control valve E serves to actuate auxiliary valves in order to direct pressure liquid from the primary pressure mps Y, Z to the main cylinder A and the return cylinders B so as to control the movement of the press ram and to unload the primary pressure pumps when the press ram is inoperative, and it also actuates the prefill and exhaust valve C in order to effect the decompression of the press, cylinder and hold the prefill valve open during the rapid return stroke of the press ram.
  • Servo-pressure is supplied by the servopump W primary pressure. liquid to operate the press rams is provided by the five pumps Y and Z.
  • the primary pressure pumps are continuously connected to the return cylinders B and primary pressure liquid from the pumps may be admitted to the main cylinder through the admission valve F which is opened by primary pressure against its spring and reflux valve H which is opened against its spring by primary pressure or by servo-pressure during automatic planishing.
  • the press ram A is prevented from falling by the liquid being locked in the return cylinders B by means of check valves X2 and X11 and the reflux valve H which is closed on the return stroke.
  • the function of valve H is to regulate the speed of the approach stroke.
  • valve H acts as a relief valve between the return cylinders and the main cylinder and on automatic planishing strokes the valve H regulates the speed of the approach stroke; itis opened on the down stroke by servo-pressure when doing automatic planishing strokes, but on forging strokes it is opened by primary pressure and closed on the up stroke by spring and servo-pressure.
  • the unloading valve 1 is intended to load and unload the two primary pressure pumps Y.
  • the unloading valve K is intended to unloadthe three primary pressure pumps Z.
  • the valve L is actuated by a tappet valve N to limit the return stroke 'ofthe press ram A.
  • a further tappet valve 0 limits the down stroke by actuating unloading valve J and also unloading valve K.
  • valves '3 and K maybe constructed in accordance with out co-pending U. S. application Serial No. 324,104 filed December 4, '1952, now Patent No. 2,805,038.
  • the relief valve Ris designed to limit the pressure of the liquid delivered by the primary pressure pumps and this relief valve may be constructed in accordance with our co-pending U. .8. application Serial No. 430,339 filed May 17, 1954, but any other suitable formof relief valve may be used.
  • the construction of valve L is substantially as shown in sectionin Fig. 1.
  • the valve S is of slightly'different construction and is as shown in section'in Fig. l.
  • the valve S is designed to direct servo-pressure from connection E4 of the directional control valve E to connection 3 of valve H during automatic'planishing strokes.
  • the control valve U is operated by means of a hand lever not shown to direct servo-pressure to the directional control valve E to cause the press ram 'Ato make a downward stroke and as pressure is built up in the cylinder A as the ram contacts the forging, the same pressure is applied to the small spindle j at the extreme left of valve U in the drawing which acts in opposition to the force applied to the hand-lever so that the force applied by press'ram A is substantially proportional to the force applied to the hand-lever and, if this is exceeded, spindle U is moved to reverse the press, ram.
  • the press may be reversed by the relief valve T acting through the valve E as will be described later.
  • the length of the return stroke is regulated by valve V as previously described.
  • the spindle 22 of the admission valve F has area 23 and a seat area 24 and it is forced into the closed position by a spring.
  • pressure at F1 acts on area 23 audit is opposed by pressure at a connection F3 plus the force of the spring.
  • the spindle is down, thereby a piston action only.
  • connection F1 from F2 pressure at c'onnection F1 acts on the annular area 23 plus pressure at F2 acting on the area 24 under the seat and opposed by the pressure at P3 acting on the area above the piston plus the force of the spring.
  • connection E of valve E is also in communication with the stroke control cylinder D on the press.
  • Connection E5 is also coupled to connection E8 by a reduced portion or neck on the spindle o.
  • connection U3 is joined to U6 by reduced portions d, e in the spindle a and because connection U6 is piped to exhaust the line at connection U3 is also to exhaust.
  • This line is joined to connection 6 of E where it takes two paths, one straight through the internal drilling s in E to connection 1 of the fixed pressure relay valve L, the second via a neck in the spindle 0 to connection E4 on E and thus to connection 2 of S.
  • connection U1 is to exhaust at.connection U6 along the reduced portion d in its spindle a, and as connection U1 is also in communication with connection 4 of the fixed pressure servo valve S, the lack of servo pressure in this line allows this valve S to come to the closed position.
  • connection 3 of the normally closed amplifier H is also connected to exhaust allowing it to close,'and isolating its connections 1 and 2.
  • connection 1 of H is piped to the return cylinders B and pressure is also locked by the check valves X2 and X11. 7
  • Connection E10 of valve E is open to exhaust along a reduced portion of its valve spindle o to connection E7, the prefill valve C connection 1 is therefore open to exhaust and C is closed by associated springs.
  • Connection 30f F the pressure actuated seated bypass-valve, is open to exhaust through connections E1 and E7 of valve E, thus F remains closed due to spring Forge ;
  • connection U1 remains coupled to exhaust atconnection U6, thus valve S remains closed, as there is no pressure on its connection 4.
  • .Also connection U2 of valve U is coupled to U6 and exhaust by its axial passage i, thus there is no pressure on connection E12 of valveE.
  • a servo-pressure line, by-passing valve B through check valve X6 puts pressure on connection E5 of E and on the small end 01 of the valve spindle 0, thus the spindle 0 of valve E is retained in its left-hand or forge position Fig. 1.
  • Con- 8 nection E5 on valve E is also inconnection with E8, via the neck in its spindle, and from E8 it is piped hack into the servo supply line.
  • Connection US on valve U is open to connection U3 via the internal drilling h and neck f in the spindle a.
  • connection 10f F As there is no servo-pressure in the line connection E1 on valve E to connection 3 on F, primary pressure acting on connection 10f F will lift the spindle of F thus joining connection 1 to 2 and hence the pumps Z can deliver to the main cylinder.
  • the pumps Y deliver via check valves X12 and X11 to connection 1 of valve H.
  • the valve opens at the pressure required to overcome the spring and the pumps deliver through connection 2 into the main cylinder line.
  • the main cylinder pressure line is also in communication with connection 1 on T and connection U8 of valve U.
  • connection E6 is subject to servo-pressure as previously described, the same servo-pressure acts through connection E1.to E11 on the left-hand area of spindle 0 as the spindle area is greater than that of the small plunger 0 at the extreme right of valve E.
  • connection E9 is coupled to E10 and therefore the primary pumps Y are coupled to the operating piston 27 of the prefill and exhaust valve C thus opening the decompression valve 26.
  • valve F closes by servo-pressure from E6 via E1 applied at connection 3 of valve F and all pumps now deliver to the return cylinders B and the press ram returns.
  • servo-pressure is cut oil? from connection U3 by U3 being joined to U6 and exhaust, which opens connection 3 of valve J and connection 3 of valve K to exhaust via L2 and L1 to U3 and allows the amplifiers J and K to open and unload the pumps. Because servo-pressure is cut off from E6 it will be cut off from E1 and E11, but as US is through to U4 servo-pressure is on E5 which causes the spindle of valve E to return .9 to the press position. Pressure liquid is locked in cylinders B by valve H as described previously under Neutral.
  • connection 4 of L When the tappet valve N is contacted at the limit of the upward stroke of the press ram connections 1 and 2 on N are joined, thus directing servo-pressure on to connection 4 of L causing its spindle to lift, isolating its connection 1 from connection 2 and connecting 2 to exhaust port 3.
  • the press ram is held up by pressure locked in the return cylinders by H and check valves X2 and X11.
  • valve U In order to make automatic planishing strokes, valve U is placed in the automatic position Fig. 3, and the lever actuated spindle is held in contact with the reversing valve at the left-hand end. In this position connection U5 is open to U1 and U3 and these connections are isolated from exhaust at connection U6 by the spindle a. Therefore, servo-pressure is applied to connection 4 on valve S lifting the spindle and opening its connection 2 to 1.
  • Servo-pressure is now applied through connections E4 and E6 on valve E to 2 on valve S, the spindle being open to 1, pressure can pass to connection 3 of H thereby lifting the spindle of valve H and opening its connections 1 to 2 and giving free passage of oil from the return cylinders B to the main cylinder A.
  • the press ram A can now fall freely by gravity, the speed of fall being controlled by the setting of valve H. Because the main ram is falling faster than pumping speed, the prefill and exhaust valve C will open allowing oil to flow by gravity into the main cylinder.
  • the primary pressure pumps are loaded as previously described. On contacting the work the prefill and exhaust valve C is closed and pressure builds up in the main cylinder, this pressure is also applied to the small spindle j at the left-hand end of U.
  • the load thus applied by the small spindle to the reversing valve 0 is opposed by the load applied at the hand lever of valve U. When the load applied by the small plunger is greater than the load applied by the hand lever, the spindle and reversing valves are moved slightly to the right.
  • connection U1 to U7 through the reversing valve seat on valve U and servo-pressure is applied through connection E11 on valve E to the left-hand end of the spindle c in valve E.
  • the spindle of E is thereby moved to the automatic reversal position Fig. 5 and reversal takes place as described under Forge.
  • the load applied by the press is substantially proportional to the load applied to the hand lever on valve U.
  • the length of return stroke is determined by the setting of stroke control valve V as previously described.
  • the press will operate automatically as long as valve U is held in the Auto position. It will be seen that the difference between forge and automatic is that in the forge position the press ram makes a single stroke and is pumped down at pump speed, whereas in the Auto position the press ram falls by gravity and makes repeated strokes.
  • connection U1 on valve U is open to connection U6 and exhaust, also connection U5 is open to U2, U3 and U4.
  • Servo-pressure is now applied through connection U2 to connection E12 on valve E thereby pushing the spindle of E to the right into the return position Fig. 6.
  • the press is now returned as previously described.
  • valve V is inoperative as U4 is coupled to US, and therefore cylinder D cannot create a pressure in excess of servo-pressure, thus the press will rise until the single interrupter valve N is contacted, when the press ram is stopped and is held by pressure liquid locked in the return cylinders 'by valve H as previously described.
  • connection US will be coupled to U2 and servo-pressure will be directed to connection l2 on E pushing the spindle to the right, this shuts off connection 4 of E from servo-pressure of connection 6 of E thus servo-pressure is removed from connection 1 on O and hence connection 4 on L, this allows the spindle in L to return to its normally open position, which allows servo pressure to pass from connection 6 on E via connections 1 and 2 on L to connections 3 on J and K, thus closing down their spindles and loading the 1.
  • control means comprising two sets of primary pressure pumps connected by conduit means to deliver directly to the one or more of the return ram cylinders during the return stroke, a servo pressure liquid supply line having means for maintaining therein in a supply of liquid at a predetermined pressure, an admission'valve connected to said conduit means and opened by the pressure therein to pass the delivery of one set of pumps to the main press cylinder for a forging stroke of the press ram, said admission valve being closed by servo pressure and operative when closed to cause said set of pumps to deliver directly to the one or more return cylinders, a servo operated reflux valve connected in said conduit means to control the rate at which liquid is displaced from the one or more return cylinders
  • Control means according to claim 2 wherein the reversing valve consists in a miter valve on a piston which is co-axial with the spindle of the manual control valve,
  • said miter valve being held on. its seat by the spindle of.
  • Control means which includes a stroke control valve which comprises a manually adjustable spindle and a piston which is movable over the spindle by pressure liquid displaced during the return stroke of the press ram by a ram which reciprocates with the press ram in a cylinder, said piston displacing liquid in advance of itself through an outlet port in the manually adjustable spindle until said outlet port is covered by the piston and the movement of the piston is halted when the pressure in the cylinder containing the said ram builds up and effectsdisplacement of the spindle of the servo operated distributing valve to its forge position and the repeating of the automatic planishing stroke.
  • a stroke control valve which comprises a manually adjustable spindle and a piston which is movable over the spindle by pressure liquid displaced during the return stroke of the press ram by a ram which reciprocates with the press ram in a cylinder, said piston displacing liquid in advance of itself through an outlet port in the manually adjustable spindle until said outlet port is covered by the piston and the movement
  • Control means according to claim 2 wherein the manual control valve has four operative'positions into which its valve member may be moved and in each of whichIthe'press is caused to perform a different function, as follows: neutral in which all pumps are unloaded, forge in which the press ram performs a normal forging stroke, auto in which the press ram makes a series of rapidly repeated short planishing strokes and return in which the press ram is reversed under the control of the operator.
  • Control means which includes two servo pressure operated relay valves one of which is arranged to control an operation of the reflux valve and the other to control the opening and closing of the two pump unloading valves.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Presses (AREA)
US573971A 1955-03-30 1956-03-26 Control valves for hydraulic presses Expired - Lifetime US2839897A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB2839897X 1955-03-30
GB922155A GB812133A (en) 1956-03-23 1956-03-23 Improvements in and relating to control valves for hydraulic presses

Publications (1)

Publication Number Publication Date
US2839897A true US2839897A (en) 1958-06-24

Family

ID=32328023

Family Applications (1)

Application Number Title Priority Date Filing Date
US573971A Expired - Lifetime US2839897A (en) 1955-03-30 1956-03-26 Control valves for hydraulic presses

Country Status (5)

Country Link
US (1) US2839897A (en)van)
BE (1) BE546574A (en)van)
CH (1) CH347059A (en)van)
FR (1) FR1148953A (en)van)
NL (2) NL105881C (en)van)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1269457B (de) * 1957-04-20 1968-05-30 Schloemann Ag Freiformschmiedepresse mit von Servomotoren oeffenbare Pressenventile

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1895710A (en) * 1931-11-24 1933-01-31 Hydraulic Press Mfg Co Hydraulic press
US2766586A (en) * 1951-05-24 1956-10-16 Electraulic Presses Ltd Control valves for hydraulic presses

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1895710A (en) * 1931-11-24 1933-01-31 Hydraulic Press Mfg Co Hydraulic press
US2766586A (en) * 1951-05-24 1956-10-16 Electraulic Presses Ltd Control valves for hydraulic presses

Also Published As

Publication number Publication date
NL105881C (en)van)
CH347059A (de) 1960-06-15
NL205911A (en)van)
BE546574A (en)van)
FR1148953A (fr) 1957-12-18

Similar Documents

Publication Publication Date Title
US2300162A (en) Hydraulic press
US3160174A (en) Remote power shift circuits for spool valves and the like
US2374593A (en) Solenoid operated valve
US3608435A (en) Pressure controlled directional system
US2070720A (en) Hydraulic press operating circuits and valves therefor
US2305610A (en) Press with die cushion
US2552604A (en) Fluid pressure control for variable delivery pump hydraulic drive system control
US2839897A (en) Control valves for hydraulic presses
US2072488A (en) Press system
US2516449A (en) Movement controlling valve means for follow-up pressure fluid servomotors and the like
US2636346A (en) Pressure accumulator circuit for hydraulic presses
US2790305A (en) Control valves for hydraulic presses
US2882766A (en) Control mechanism for hydraulic presses
US2577981A (en) Hydraulic motor control
US2766586A (en) Control valves for hydraulic presses
US2928423A (en) Pressure relief and valve spool positioning mechanism
US2861426A (en) Control valves for hydraulic presses
US2823647A (en) Valve system and apparatus for controlling eluid actuated servomotor
US2098425A (en) Control mechanism for pumps
US2545246A (en) Main cylinder release and pump bypass valve
US2300338A (en) Hydraulic press and the like
US2967485A (en) Pressure actuated by-pass valves
US2462815A (en) Valve system for hydraulic press circuits
US2449400A (en) Follow-up type servomotor
DE750470C (de) Druckstelze fuer Pressen o. dgl.