US3105398A

US3105398A - Dynamic forming machine

Info

Publication number: US3105398A
Application number: US122736A
Authority: US
Inventors: Josef K Murek
Original assignee: General Dynamics Corp
Current assignee: General Dynamics Corp
Priority date: 1961-07-10
Filing date: 1961-07-10
Publication date: 1963-10-01
Anticipated expiration: 1980-10-01

Description

Oct.. 1, 1963 J, K, MUREK 3,105,398

DYNAMIC FORMING MACHINE Filed July 10, 1961 4 Sheets-Sheet 1 INV EN TOR.

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Oct. 1, 1963 J. K. MUREK DYNAMIC FORMING MACHINE Filed July 10. 1961 4 Sheets-Sheet 2 w ,m //.////Aw e Oct. 1; 1963 J. K. MUREK DYNAMIC FORMING MACHINE Filed July 10. 1961 4 Sheets-Sheet 3 -V I |92 Qbss' M. Mapex,

INV EN TOR.

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Oct. 1, 1963 J, K, MUREK 3,105,398

' DYNAMIC FORMING MACHINE Filed July 10. 1961 4 Sheets-Sheet 4 JSEF MURE/1:,

INV EN TOR.

tion of Delaware Filed luly 1G, 196i, Ser. No. 3.22,'736

5 Claims. (Si. 78-42) The present invention relates generally to high energy rate forming machines; more particularly, the invention relates to dynamic forming machines adapted for repetitive cycling.

High energy rate forming machines for repetitive cycling yoperation have had a number of disadvantages and shortcomings. A considerable number of steps and control functions have generally been involved in such operation of the machine. Automatic cycling has generally required the use of relatively complex actuators. Some machines have required more than one hydraulic system for automatic repetitive cycling. Some have had the disadvantage and expense of losing or dumping quantities of operating gases on each cycle of operation. Such machines have had relatively extensive maintenance problems.

The present invention provides a high energy rate forming machine which is adapted for repetitive cycling of operation by a pressure-actuated floating reseating piston for reseating an actuator piston preparatory to operation. The machine is adapted for automatic repetitive cycling by a control system including electrically operating control valves which operate to apply reseating pressure to the reseating piston, to relieve the reseating pressure prior to operation, and to apply a triggering pressure to the actuator piston to initiate actuator operation. The machine preferably includes a frame on which an actuator is mounted and to which a bolster is connected. An actuator piston is cooperable with a wall in the actuator to provide a pressure :seal between the piston and the wall separating areas of the piston. A ram connected with the actuator pistou confronts the bolster. A oating reseating piston is slidable in the actuator on the side of the actuator piston opposite from the wall. Hydraulic reseating pressure is applied to the reseating piston to urge the piston toward the wall to establish `the pressure seal and prior to actuator operation, this reseating pressure is relieved. Actuator operation is preferably initiated by the application of a tniggering force to the actuator piston, preferably by a tiiggerin pressure applied to an area of the actuator piston. The triggering force overbalances the forces on the piston to eliminate the pressure seal between the actuator piston and the wall, thereby releasing an actuating pressure upon an area of the actuator piston. The actuator piston is thereby impelled from the wall to impel the ram to impact the bolster.

In a preferred embodiment of the invention, an orifice is detined in the wall in the actuator and the abovementioned pressure seal is established about this oriiice. The wall separates an actuating pressure chamber and a set pressure chamber. A set pressure exerts a set force on the actuator piston to urge it toward the wall, and the actuating pressure acts oppositely on the actuator piston. The set pressure is introduced through an inlet tube which is secured to a bridge portion of the orifice wall which separates two portions of the orlce, and which extends into an axial bore in the actuator piston and in a thrust column which interconnects the piston md the ram. A frame structure includes guide rods which carry support pistons whichL are acted upon by pressure in damping assemblies to support the frame structure and the bolster. Upon impact of the ram on the bolster, the end portions of the guide rods are urged into damping cylinders in the damping assemblies to eifect predeterted States Patent masses mined deceleration of the frame and bolster assembly by forcing oil outwardly through graduated damping holes in the damping cylinder.

An electrically operated and automatically functioning pressure valve control system may preferably be utilized to provide automatic recycling ror repetitive operation of the forming machine. A normally open electrically operated irst valve permits oil under a reseating pressure to pass kfrom a supply to the reseating piston. A switch is operable upon movement of the ram into its upward position, to close this valve to stop the supply of reseating pressure. An automatic switch is responsive to the pressure drop produced by the closi-ng of the irst valve and momentarily opens another valve to apply a fburst of triggering pressure to an actuator piston area to effect Voverbalancing of the forces on the piston, thereby eliminating the pressure seal and releasing the actuating pressure upon an area of the actuator piston. This impels the actuator piston from the wall to impel the ram to impact the bolster.

lt is therefore an object of the present invention to provide a high energy rate forming machine which is adapted for convenient and economical repetitive operation.

An object of the invention is the provision of a high energy rate forming machine which is adapted for automatic recycling with a relatively simple actuator.

lt is an object of the invention to provide a high energy rate forming machine Which provides automatic repetitive cycling with improved reliability, ease of control and eihciency.

An object of this invention is to provide a dynamic forming machine which provides convenient and eii'icient repetitive cycling with a relatively simple actuator by utilizing a floating reseating piston arrangement for reseating an actuator piston preparatory to repeat operation.

It is an object of the present invention to provide a high energy rate forming machine according to the foregoing object wherein a novel pressure inlet tube arrangement facilitates the use of the oating reseating piston by permitting overlapping travel of the reseating piston and the actuator piston.

An object of this invention is the provision of a high energy rate forming `machine according to the foregoing objects wherein portions of an orifice Wall are separated by a wall bridge portion which provides means for mounting the pressure inlet tube.

It is an object of the invention to provide y"al dynamic forming machine which provides improved etliciency and economy in repetitive operation by eliminating loss of operating gas on each cycle of operation.

An object of the present invention is to provide a high energy rate forming machine wherein an hydraulically actuated reseating piston reseats an actuator piston preparatory to repetitive actuator operation and wherein the reseating piston separates oil under a reseating pressure from operating gas pressure, thereby prccluding loss of gas on each cycle of operation.

It is an object of the invention to provide a control valve system which facilitates automatic repetitive cycling of a dynamic forming machine utilizing a relatively simple high energy rate actuator.

Another object of the invention is the provision of a control valve system according to the foregoing object wherein automatic electrically operated valves apply reseating pressure to a reseating piston to reseat an actuator piston preparatory to operation, then relieve t Ae reseating pressure from the reseating piston, and apply a triggering pressure to the actuator piston to overhalance the force thereon to initiate actuator operation.

Another object of the invention is to provide a high energy rate forming machine which substantially reduces the maintenance problems associated with automatic cycling high energy rate forming machines.

Other objects, features and advantages of the present invention will become apparent to those versed in the art from a consideration of the following description, the appended claims and the accompanying drawings, wherein:

FIGURE 1 is an elevational view, partially in section, of a preferred embodiment of the forming machine of the present invention;

FIGURE 2 is an enlarged sectional View taken at line 2 2 of FIGURE l;

FIGURE 3 is a sectional view taken at line 3 3 of FGURE 2;

FIGURE 4 is an enlarged fragmentary sectional View showing details of the actuator assembly utilized with the dynamic forming machine of FIGURE l;

FlGURE 5 is an enlarged partial sectional view showing details of the damping assembly of the dynamic forming machine of FIGURE l;

FIGURE 6 is an enlarged fragmentary sectional view showing details of a limit switch utilized with the dynamic forming machine of FIGURE 1;

FIGURE 7 is an enlarged sectional View, taken at line '7-7 of FIGURE l; and Y FIGURE 8 is a diagramamtic illustration of a triggering pressure system and a hydraulic reseating pressure system which may be utilized with the dynamic forming machine of FIGURE l.

Referring to the drawings, and particularly lto FIG- URES l and 7, there is shown a preferred embodiment of the dynamic forging machine of the present invention. Two identical vertical support beams 10, each having a wide central web portion and end anges 1-2, 14, are Welded in spaced relation on opposite end portions of a base plate 16. The base plate is secured to a foundation 18 by bolts 2t). A cover plate 22 is secured by screws to upper portions of the end anges 14 of the beams 10, and another cover plate 24 is similarly secured by screws between the lower portions of flanges 14 of the beams.

A unitary frame and bolster assembly 26 includes an end plate 28 and a bolster assembly .39, which are rigidly interconnected by four guide rods .32. Threaded end portions of the guide rods extend through appropriate openings in the end plate, and each guide rod is secured to the end plate by

nuts

34, 36 which engage a threaded upper portion of lthe guide rod and clamp end plate between them, as shown.

The bolster assembly and a lower section 4G. rod 32 extends through 3@ comprises an upper section 38 A threaded portion of each guide appropriate aligned openings in the bolster sections, and are secured to each guide rod by nuts 42', '44 which are disposed in recesses on opposite sides of the bolster assembly and which threadedly engage the guide rods. A die part 46 is secured to the bolster by bolts 48 which extend through openings in a flange portion of the die part. A die cavity or recess 5i) is defined in the die part and a workpiece 52 is positioned atop the die.

As shown in FIGURES 1 and 5, an annular support piston 54 is secured to a threaded portion of the guide rod and spaced a short distance from its end. The piston is slidable in a cylindrical section 56 of a damping assembly 58. A'peripheral bearing 60 is provided on the piston. The damping assembly includes an upper end cap 62, a lower end cap 64 and the cylindrical section 56, these parts being secured in clamped relation by a plurality of tie bolts 66 which extend through circularly arranged vopenings in the upper end cap and are secured by engagement of their threaded lower end portions in openings in the base plate 16. Pressure sealing for the damping assembly is provided by seal rings 63 positioned between the respective end caps and the cylindrical section S6 ,7

in appropriate grooves in the end caps.

A reduced end portion 76 of each guide rod is slidable within a damping cylinder 72, which is secured to the lower end cap 64 by engagement of its end portion in a threaded circular recess in the end cap. A plurality of damping orifices are provided in 4the damping cylinder. For a purpose which is hereinafter described in relation to the operation of the damping assembly, these orifices are graduated and decrease in size in accordance with their distance from the top of the damping cylinder, as shown. A pool or reservoir of oil is provided about the damping cylinder.

A support pressure chamber 74 in the damping assembly is deiined by the cylindrical section 56, the lower end cap 6d and the support piston 54. The chamber is connected by a port '76 in the cylindrical section and a fluid coupling with a source of support pressure (not shown). The support pressure acts on the support piston to support the machine assembly, including the frame and bolster assembly 26, the actuator assembly and the ram. The pressure provides the supporting force by acting upon the effective differential area between the two sides of the support piston, because the support pressure exists in the space above the piston.

An actuator assembly Sti is mounted on the frame and bolster assembly 25. The actuator assembly is secured to the end member 28 by tie rods S2 which extend through appropriate openings in the end plate and have their end portions in threaded engagement in a bottom end plate 84. The guide rods 32 extend through respective openings in the bottom plate 34, and two rod bearing halves are secured by screws in a circular recess in the plate about each of the guide rods. An actuator housing is formed by an upper end cap Se, a lower end member 3, cylindrical sections 99, 92, an orifice wall member 9d and the bottom plate 84, all of which `are secured in clamped relation by the tie rods SZ, as hereinb-efore mentioned. Pressure sealing for the actuator housing is provided by resilient seal rings between the cylindrical sections, the end caps and the orifice wall, the seal rings being disposed in appropriate grooves in the respective end caps and in the orifice plate, -as shown.

Referring to FGURES l, 2 and 3, the orifice wall member 94 has an orifice defined therein, which is formed of a lower axial orice portion 93 and two generally rectangular upper orifice portions 19d, 192 separated by a bridge portion 16d of the orifice wall member. As shown, the bridge portion 1414 is thinner than the remainder of the orifice wall, so that the upper orifice portions communicate with the lower orifice portion 9d through the space under the bridge portion 1de. rthe orifice wall 94 separates an actuating pressure chamber 1535 and a set pressure chamber 168 in the actuator housing.

An actuator piston 11i) is slidable in cylindrical section 92 and in the set pressure chamber 1%. A sealing ring in a peripheral groove of the piston provides pressure sealing between the piston and the cylindrical section $2. A thrust column 112 is secured by engagement or its threaded reduced end portion axial opening in the piston. The thrust column extends through the lower end `of the actuator housing, and is slidably received in a bearing 116 mounted in the lower end member 88. A seal ring in a groove in the lower end member @8 about the thrust column provides pressure sealing.

An annular seal base 118 (FIGURE 4) is disposed in an end recess of the thrust column and confronts the orifice wall 94. The seal base is retained by a tube bearing 12d which is threadedly secured in an axial opening 122 in the thrust column. A seal ring '12d in an end of the thrust column provides pressure sealing between the seal base and the thrust column, andra seal ring 126 in a groove in the bearing provides pressure sealing between the seal base and the tube bearing. A circular resilient 5 sealing element 12S is secured as by bonding in a circular 114 (FIGURE 4) in an ,i

groove in the seal base in confronting relation with the surface of the orice wall member 94.

A generally rectangular ram assembly 13W is attached to the thrust column by threaded engagement of an end portion of the thrust column in an opening in an upper ram section 132. Upper section 132 is secured to a main ram section 134 by bolts 136, as shown. The ram assembly 139 is slidably mounted on the four guide rods 32 by arcuate bearing elements 138 which are secured in arcuate recesses in the respective corners of the rectangular main ram section 134. Each arcuate bearing element is secured against a recess shoulder by a bolt 14d. A male die part or punch 142 is secured by bolts to the lower surface of the ram.

A limit switch 144 is mounted in an opening in bottom end plate 34 and includes an insulating member 145 which threadedly engages an opening in the bottom end plate. A body member 145 is secured in a threaded bore in the insulating member. A helical spring 15@ and a contact plunger 152 are mounted in an axial opening in the body member. The spring exerts a biasing force on an enlarged portion 154 of the plunger, and a cap member 156 retains the plunger. When the upper bolster section 132 contacts and depresses the plunger 152 of the switch, an electrical circuit is completed through the ram, the plunger 152, cap member 156 and a wire 158.

Referring to FIGURES 2, 3 and 4, a set pressure inlet tube 169 is secured to the bridge portion 1de of the orifice wall member by engagement of its threaded end portion in an opening in the bridge section and is securely locked by nuts 162., 154. A radial passage 166 in the oriice wall is connected with a source of set pressure (not shown) by a uid coupling 16S and communicates with the set pressure inlet tube 169 through the opening in the orifice wall bridge section 1134 in which the inlet tube 164i is threadedly secured. The set pressure inlet tube 169 extends into an axial bore 17% in the thrust column and is slidably received in the tube bearing 120. A sliding pressure seal between the 4tube bearing and the tube is provided by a seal ring in a groove in the tube bearing. A radial opening 172 in the thrust column communicates between the bore 17@ and the set pressure chamber 193.

From the foregoing description and the drawings, it will be understood that the set pressure chamber 168 is connected with a source of set pressure (not shown) by the radial passage 172 and axial bore 17@ in the thrust column, the set pressure inlet tube 16%, the radialrpassage 166 in the orijice wall member, and the uid coupling 163.

An actuating pressure chamber 136 is connected with a source of actuating pressure (not shown) by a passage 174 in the orilice -wall member and a iiuid coupling 176. A passage 173 in the orice wall member and a fluid coupling 1% are connected with a source of triggering pressure (not shown) for a purpose hereinafter described.

An annular oating reseating piston 182 is slidable in the set pressure chamber 163 and is slidable on the thrust column by means of its am'al bore 184. A recessed portion 136 of 4the piston ser-ves a purpose which is hereinafter described. Pressure sealing between the piston and cylindrical section 92 is provided by a seal ring in a peripheral groove of ythe piston, and sealing between the thrust column and the piston is provided by a seal ring in a groove in the bore of the piston.

The set pressure chamber 193 is connected with a source of hydraulic reseating pressure (shown in FIG- URE 8) by a passage 188 in the lower end member S8 and by a uid coupling 19d. A pressure-responsive switch 192 communicates with the passage 1% and the iluid coupling through a passage 194, for a purpose hereinafter described.

To prepare the machine for operation, quantities of gas under appropriate pressures are introduced into the actuating pressure chamber 106, the set pressure chamber 10S, and the support pressure chamber 74. The support pressure is introduced into chamber Fifi (FGURES 5 and 1) through the fluid couplings 7S and ports '76. This pressure is such that by acting on the support pistons 4 it exerts -suicient force to support the entire bolster and frame assembly 26 of the machine. A relatively high actuating pres-sure is introduced into actuating pressure chamber 196 through the fluid coupling 175 and the passage 174 in the yorifice wall. A relatively low set pressure is established in set pressure chamber 193 from a source of set pressure (not shown) through iiuid coupling 168, passage 166 in the orifice wall member, set pressure inlet tube 161i, and the bore 170 and radial passage 172 in the thrust column. This pressure acts on the area of the actuator piston outside thrust column 11-2 to urge the actuator piston 11? toward the orifice wall member 94 to eiect a positive pressure seal between the piston and the -wall member by means of the circular resilient sealing element 123. The actuating pressure in chamber 106 is preferably sufficient in acting through orice portions 109, 192 upon the actuator piston area within the circular sealing element 128, to substantially balance the opposing force of the set pressure on the piston.

To initiate operation of the machine, a triggering pressure is introduced through the fluid coupling 18% and the pas-sage 178 in the oriiice wall member 94 to act yupon the area of actuator piston 110 radially outside the pressure seal between the annular resilient sealing element 128 and the orice wall member. The torce of the triggering pressure -on this area eiects sudden disengagement of the press-ure seal at the resilient sealing element 128. 'Ihe actuating pressure is thereby suddenly released upon the piston area radially outside the sealing element 1.28. The actuator piston is thereby suddenly impelled from the orifice wall, and the ram assembly 139 is impelled downwardly at high velocity.

In reaction to the rapid downward movement of the actuator piston and ram assembly, the entire frame and bolster assembly 26, including the guide rod 32 and the #bolster assembly, moves upwardly a distance which is relatively shorter in proportion to the relative masses of the respective assemblies. The reduced end portions 7G' of the guide rods being slidable in the damping cylinders 72, the upward movement of the guide rods causes their end portions itl to draw oil into the damping cylinders through the damping openings 73 from the supply in the damping assembly.

The ram assembly impacts the bolster assembly at high velocity, the impact between the die part 142 on the ram and the die pant 46 on the bolster assembly results in the high rate application of energy to eti-ect forming of the workpiece by the die parts. The opposing movements of the ram assembly 13o and the frame and bolster assembly 26 increase the energy which is imparted to the workpiece 52.

After the impact of the ram upon the bolster, the frame and bolster assembly 26 moves downwardly. This downward movement urges the end portions 7@ of the respective guide rods 32 into the damping cylinders to force the oil in the damping cylinders outwardly through the damping openings 73. Pressure dilerentials are thereby established across these openings which produce decelerating forces on the guide rods. Because of the graduated decreasing sizes of the damping orifices, the pressure dilerentials across the orifices increase and the decelerating forces increase as the guide rods move downwardly. The decelerating force therefore becomes progressively greater as the frame and bolster assembly moves downward, and predetermined or controlled deceleration lof the frame and bolster assembly is thus eiected.

After the downward movement of the frame and bolster assembly 25 has been stopped, the support presa sure in the chambers 74 of the damping assemblies urges the assembly upward and supports it in the position shown in FlGURE 1.

To prepare the actuator and the machine for repeat operation, the actuator piston must be reseated against the oriiice wall member 94 to -re-establish the pressure seal between them at the circular resilient sealing element 123, and to raise the ram assembly to its upward position. Reseating or" the actuator pist-on 11) and the raising of the ram assembly-13G` are eiected by introducing a hydraulic reseating pressure into the set pressure chamber 168 beneath the oating reseating piston 132. This hydraulic reseating pressure urges the reseating piston upward to raise the actuator piston and the ram asselibly. The floating reseating piston 1&2 may preferably contact the actuator piston, and the gas in the set pressure chamber is preferably compressed within the space delined between the pistons by the relief portion 186 of the reseating piston. The raising of the actuator piston by the action of the hydraulic reseating pressure on the reseating piston 182 eifects compression `of the actuating pressure into the actuating pressure chamber 195.

After the actuator piston is reseated the application of hydraulic reseating pressure to the reseating piston is stopped. This permits the pressure of the gas compressed in the set pressure chamber 1&8 to force the floating reseating piston 132 downward, thereby forcing the oil out of the set pressure chamber through the passage 18%V and the iluid coupling .190, and seating the'reseating piston against the lower end member 8S in the position shown in phantom outline in FGURE 4. The expansion of the 'gas above the reseating piston reestablishes the original set pressure in set pressure chamber 103.

Upon vthe reseating of lthe actuator piston 116, the trapping of pressure in the space defined between the orifice wall member 94- and the actuator piston 119 by the circular resilient sealing element 123 and the seal ring between cylindrical section 92 and the piston, is prevented by relieving pressure from this space through the passage 173 in the lorice wall and the fluid coupling 18?. If it were not released, pressure trapped in this space would act upon the actuator piston area radially outside the sealing element i128 and would oppose the force exerted ioppositely -upon the piston by the set pressure. Proper re-establishment yof the pressure seal at the resilient sealing element 128 could not be effected, because the actuating pressure in chamber 196 would be more than sucient to overbalance the force exerted oppositely on the actuator piston by the set pressure. This would preclude actuator operation, because the piston would be moved and the seal would be disengaged by the action of a relatively low pressure in the actuating pressure chamber 1%, instead of by the proper actuating pressure.

The floating reseating piston 182 serves the important function of separating an oil system and a gas system. It is highly desirable to utilize an hydraulic system and hydraulic reseating pressure, because of its positive action, rapidity and eciency. The separation of the oilV and gas systems by the iloating piston prevents mixing of gas and oil, which would involve problems. Absorption of gas in the set pressure chamber into the oil would produce a `drop in set pressure. It would also result in substantial losses of lgas by the venting thereof from the hydraulic system. Further, absorption of gas into the oil would produce a compressible foamy mixture. This would result in relatively ineicient operation and would require extra time for reseating. The pump supplying hydraulic pressure could not function properly and the compressble mixture and pump life would be much shorter.

The utility of the set pressure inlet tube arrangement is apparent from the foregoing description. lt permits overlapping travel of the actuator piston 11%` and the floating reseating piston 182. An inlet port for supplying set pressure cannot effectively be provided in the wall of the actuator, because of the overlapping travel. It would be diiiicult to insure proper positioning or alignment of the pistons and an inlet port at the times when set pressure must be admitted. The sealing rings in the peripheral grooves in the actuator piston and the reseating piston would have relatively short service lives if such an inlet port were used, because they would tend to be damaged in moving past the inlet port.

FIGURE 8 schematically illustrates anautomatic hydraulic reseating pressure systeni and an automatic gas triggering pressure system which may preferably be utilized for the automatic repetitive recycling of the dynamic forging machine of the invention.

A normally closed solenoid-operated valve 1% is 'connected in the fluid coupling 18u' which interconnects the passage 17S in the orilice wall member `9d with a source of triggering pressure (not shown). Actuation of the valve admits triggering pressure through the coupling 13) to the passage 173. A normally open solenoid-operated valve 19S communicates with the line 186' and normally provides communication between the passage in the orifice wall and the exterior atmosphere. Upon actuation the valve closes to prevent release of pressure from the passage 178 to the atmosphere. As indicated schematically in FIGURE I8, valves 196 and 193 are electrically connected with the pressure-operated switch i192 through relays Zilli, 202, respectively.

As hereinbefore described relative to FIGURE 4, the uid coupling 1% interconnects passage 13S below lloating piston 182 `with a source of hydraulic reseating pressure, and the pressure-responsive switch 192 communi- Cates with line and passage 188. A hydraulic pump 204 powered by a motor 206 is mounted in the line 19t) and supplies oil under a reseating pressure from reservoir 268 through the coupling 190' and the passage y183 to the set pressure chamber beneath the loating piston 182. A normally open solenoid-actuated valve 210 is connected in the line k194i, and actuation of the valve stops the application of oil under the reseating pressure through the line. A relief valve 212 is connected with coupling 190 by a by-pass coupling 214 and permits oil under pressure lfrom the pump 294 to pass directly back to the reservoir when the valve 210 Vis closed. A normally closed solenoid-operated valve 216 communicates through a coupling 218 with coupling 19t) and passage 1-88. Actuation thereof releases hydraulic pressure from the set pressure chamber beneath the floating piston 182 and permits the oil to pass to the reservoir 208.

The automatic electrically operated hydraulic reseating pressure system and triggering pressure system of FIG- URE 8 effect automatic repetitive cycling of the dynamic forming machine of FIGURES l through 7.

Referring to FIGURE 8, at the start of ay cycle of operation of the machine, a relay system (not shown) closes the valve 216 and opens the valve 210, while valve 198 is open to atmosphere and valve 19.5 is closed. The open valve 210 admits oil from the pump 212 to the reseating piston, and the closed valve 216 prevents the loss of reseating pressure from the set pressure chamber 16S to the reservoir 2103. Oil under the reseating pressure passes through the coupling 190 and passage 18S to the dloating reseating piston. The reseating piston is thereby urged toward or against actuator piston 11@ and the actuator piston is moved to its upward position shown in FIGURE 4, wherein a positive pressure seal is provided between the orice wall 914 and the actuator pist0n by the annular sealing element 128. The gas in set pressure `chamber 1418 between the pistons is substantially compressed within the space defined by the relief portion 186 of the reseating piston.

The upward movement of the actuator piston to the position shown in FIGURE 4 carries the ram assembly 130 to its upward position, as shown in FIGURE 1. As the ram assembly moves into this position its upper section 132 contacts and depresses the plunger 152 of limit switch 144. The switch initiates operation of a relay system (not shown) which after a time delay closes the solenoid operated valve 210, opens the solenoid operated valve 198, and opens the valve 216 (FIGURE 8). The closing of valve 210 stops the application of oil under rescating pressure from the pump to the reseating piston. The opening of valve `198 releases to the exterior atmosphere pressure which may be trapped between the actuator piston and the orifice wall in the space dened between resilient sealing element 128 and the peripheral sealing ring on the actuator piston, for the purpose which is hereinbefore described. The opening of valve 216 permits oil under the reseating pressure to pass vfrom the set pressure chamber to the reservoir. The gas compressed in set pressure .chamber 108 above the reseating piston 182 urges the reseating piston downwardly to the position shown in phantom outline in FIGURE 4. It is seated against lower end member l88 of the actuator assembly. This downward movement of the reseating piston forces the oil through passage 188 and coupling 190 to the reservoir 208.

Upon the seating of the reseating piston in the position shown in phantom outline in FIGURE 4, the pressure in the passage 188 and coupling 190 drops substantially to zero. The pressure-responsive switch 192 responds to this pressure drop iand acts through the relay system 292, 200, respectively to close the valve 198 and to momentarily open the valve 196. The closing of valve 198 prevents loss of triggering pressure to the exterior atmosphere. The momentary opening of valve 196 admits a burst of triggering pressure from the source of triggering pressure (not shown) through the coupling 180 into the space defined radially outside the circular resilient sealing element 128 and within the peripheral sealing ring of the actuator piston. This burst of triggering pressure to this piston `area unseats the actuator piston from the oriiice wall member 94 and disen-gages the pressure seal. The actuating pressure in'chamber 106 is thereby suddenly applied to the actuator piston tarea readily outside the resilient sealing element 128, and the actuator piston is rapidly impelled downwardly.

The downward -movement of the ram and the impacting of the workpiece carried by the bolster is followed by the operation' of the damping assembly, as hereinbefore described. A cycle of operation of the machine is thus completed, `.and a new cycle commences with the opening of valve 210 and the closing of valve 216 by the operation of the relay system.

From the foregoing description and from the drawings, it ywill be understood that the triggering pressure system and the ihydraulic reseating pressure system, shown diagrammatically in FIGURE 8, etect automatic repetitive operation' of the dyn-amic forming machine of the invention.

From the foregoing description, those versed in the :art will appreciate that the present invention achieves the objects and realizes the advantages hereinbefore mentioned.

Although specic embodiments of the present invention have been' illustrated and described herein, it will be understood that the same are merely exemplary of presently preferred embodime-nts capable of attaining the objects :and advantages hereinbefore mentioned, and that the invention is not limited thereto; variations will be readily apparent to those versed in the art, and the invention -is to be given its broadest possible interpretation within the terms of the -appended claims.

I claim:

1. A high energy rate forming machine comprising frame means, actuator means carried by the frame means, bolster means connected with the vframe means, an actuator piston slidable in the -actuator and confronting a wall therein, resilient sealing means between said piston and the wall for providing a pressure seal therebetween deining separate areas of the actuator piston', ram means connected with said actuator piston and confronting said bolster means, means establishing `an `actuating pressure in the actuator, a floating reseating piston slidable -in the actuator on the opposite side of said actuator piston' from said wall, `an oil reservoir, conduit means communicating between the reservoir `and the reseating piston, pump means -for supplying oil under a reseating pressure from said reservoir through the conduit means to the reseating piston, electrically operable normally open first valve means in the conduit means between the reservoir and the reseating piston, electrically operable normally closed second valve means interconnecting said conduit means and the reservoir, electrical means for opening said rst valve means to admit oil under the reseating pressure from the pump means to the reseating piston' and to close said second valve means to prevent loss of reseating pressure to the reservoir, said reseating pressure urging the reseating piston and the actuator piston toward said wall to prepare the actuator for operation and to move the ram means to its upward position, electrically operable normally open third valve means interconnecting said second :actuator piston area and the exterior atmosphere, limit switch means openable upon movement of the ram means into said upward position to close the first valve means to stop the supply of oil under reseating pressure from the pump means and to open the thi-rd valve means to relieve pressure trapped between the actuator piston and said wall, and to open the second valve means to release oil under reseating pressure from the reseating piston to the reservoir, electrically operable normally closed fourth valve means interconnecting a source of triggering pressure with said second Aactuator piston area, and switch means responsive to the pressure `drop caused by said closing of the rst valve means to close lthe third valve means to prevent loss of triggering pressure to the exterior atmosphere and to momentarily open the fourth valve means for a momentary application of triggering pressure to said second actuator piston area to overbalance the forces on the piston to eliminate said pressure seal and release the actuating pressure upon said second actuator piston area, whereby the actuator piston is impelled from said wall to impel said ram means to impact the bolster means.

2. A high energy rate forming machine comprising frame means, actuator means carried by the frame means, bolster means connected with the frame means, a wall dening two orifice portions separated by a wall bridge portion, said orice wall separating an actuating pressure chamber and a set pressure chamber in said actuator, an actuator piston slidable in said set pressure chamberV and confronting said orifice wall, a thrust column connected with the actuator piston and extending from the actuator, said actuator piston and said orifice wall being adapted for cooperation to provide a pressure seal therebetween about said orice, a set pressure inlet tube secured to said wall bridge portion and extending into an axial bore in the actuator piston and in the thrust column, said thrust column and actuator piston being movable relative to the inlet tube, said thrust column having passage means communicating between the thrust column rbore and the set pressure chamber, means for introducing a set pressure through said inlet tube, said bore and said passage into the set pressure chamber, said set pressure acting on the actuator piston to urge the pistou toward the wall, means for establishing a relatively high actuating pressure in the actuating pressure chamber to act on the actuator piston in a direction opposite to the action of the set pressure, ram means conneced with the thrust column and confronting said bolster means, a floating reseating piston slidable in the actuator on the opposite side of the actuator piston from said wall, means for applying hydraulic reseating pressure to said reseating piston to urge the actuator piston toward the wall against the action of the actuating pressure to establish said pressure seal about the oriice to prepare the actuator for operation, means for relieving the reseating pressure from the reseating piston preparatory to actuator operation, said set pressure in the set pressure chamber exerting a set force urging the actuator piston toward the orifice `wall to maintain said pressure seal, and means for applying a triggering force to the actuator piston to cooperate with the actuating pressure in overbalancing the set force to eliminate said pressure seal and release the actuating pressure upon an increased area or the actuator piston, whereby the ac-tuator piston is impelled from said -wall to impel the ram means to impact the bolster means.

3, A high energy rate forming machine comprising frame means, actuator means carried by the frame means, bolster means connected with the fname means, a wall defining au oriiice between an actuating pressure chamber and a set pressure chamber in said actuator, an actuator piston slidable in said set pressure chamber and confronting said orice wall, resilient sealing means positioned between the actuator piston and said orifice wall for providing a pressure seal therebetween about the orice and separating rirst and second .area of the actuator piston, means for establishing a relatively low set pressure in the set pressure chamber to act on the actuator piston to urge the piston toward the wall, means for establishing a relatively high actuating pressure the actuating pressure chamber to act on the actuator piston `in a direction opposite to the action of the set pressure, ram means connected with the actuator piston and confronting said bolster means, a iioating reseating piston slidable in the actuator on lthe opposite side of the actuator piston from said wall, an oil reservoir, conduit` means communieating between the reservoir and the reseating piston, pump means for supplying oil under a reseating pressure from said reservoir through the conduit means to the reseating piston, electrically operabie normally open first valve means in the conduit ymeans between the reservoir and the reseating piston, electrically operable normally closed second vadve means interconnecting said conduit means and the reservoir, electrical means for opening said iirst valve mee-uis to admit oil under the reseating pressure from Ithe pump means to the reseating piston and to close said second valve means to prevent loss of res-eating pressure to the reservoir, said reseating pressure urging the reseating piston and the actuator piston toward said wall to prepare the actuator for operation and to move the ram means to its upward position, electrically operable Vnormally open third valve means interconnecting said second actuator piston area and the exterior atmosphere, limit switch means operable upon movement of the ram means into said upward position to close the iirst valve means to stop the supply of oil under reseating pressure from the pump means and to open the third valve means Ito relieve pressure trapped between the actuator piston and said wall, and to open the second valve means to release oil under reseating pressure from the reseating piston to the reservoir, electrically operable normally closed fourth valve means interconnecting a source of triggering pressure with said second actuator piston area, and switch means responsive to the pressure .drop caused by said closing of the iirst valve 4means to close the third valve means to prevent yloss of triggering pressure to the exterior atmosphere and to momentarily open the fourth valve means for a momentary application of triggering pressure to cooperate with the force of the actuating pressure on said iirst actuator piston area to overbalance the forces on the piston to eliminate said pressure seal and release the actuating pressure upon said second actuator piston area, whereby the actuator piston is impelied from l2 said wall to impel said ram means to impact the bolster means.

4. A high energy rate forming machine comprising frame means, actuator means carried by the frame means, bolster means connected with the trame means, a wall defining two orifice portions separated yby a Wall bridge portion, said oriiice wall separating an actuating pressure chamber land la set pressure chamber in said actuator, an actuator piston slidable in said set pressure chamber and confronting said oriiice wall, a thrust column connected with the actuator piston and extending from the actuator, said actuator piston and said oriiice wall being adapted for cooperation to provide a pressure seal therebetween about said orifice, la set pressure inlet tube secured to said -wall `bridge portion and extending into an axial bore in the actuator piston and in the thrust column, said thrust column and actuator piston being movable relative to the inlet tube, said thrust column having passagemeans communicating between the thrust column bore and the set pressure chamber, means for introducing a set pressure through said inlet tube, said bore and said passage into the set pressure chamber, said set pressure acting on the actuator piston to urge the piston toward the wall, means for establishing a relatively high actuating pressure in the actuating prcssure cham-ber to -act on the actuator piston in a direction opposite to the-action of the set pressure, ram means connected with the thrust column and confronting said bolster means, a floating reseating piston slidable in the actuator on the opposite side of the actuator piston from said Wall, an oil reservoir, conduit means communicating between the reservoir and the reseating piston, pump means for supplying oil under a reseating pressure from said reservoir through the conduit means to thereseating piston, electrically operable normally open trst valve means in the conduit means between the reservoir and the reseating piston, electrically operable normally closed second valve means interconnecting said conduit means and the reservoir, electrical means for opening said first valve means to admit oil under the reseating pressure from the pump means to the reseating piston and to close said second valve means 1to prevent loss of reseating pressure to the reservoir, said reseating pressure urging the reseating piston and the actuator piston toward said wall to prepare the actuator for operation and to move the ram means to its upward position, limit switch means operable upon movement of the ram means into said upward position to close the first valve means to stop the supply of oil under reseating pressure from the pump means and to open the -second valve me-ans to release oil under rescating pressure from the reseating piston to the reservoir, said set pressure in the set pressure chamberexerting a set force urging the actuator piston toward the orice wall to maintain said pressure seal, and means for lapplying a triggering for-ce to the actuator piston to cooperate with the actuating pressure in overbalancing the set force to eliminate said pressure seal and release the actuating pressure upon an increased area of the actuator piston, whereby the actuator piston is impelled from said wall to impel the ram means to impact the bolster means.

5. A high energy rate vforming machine comprising frame means, actuator means carried by the frame means,

- bolster means connected with the rame means, a wall defining two orifice portions separated by a -wall bridge portion, said orifice Vwall separating `an actuating pressure chamber and ia set pressure chamber in said actuator, an actuator piston slidable in said set pressure chamber and confronting said orifice wall, a 'thrust column connected with the actuator piston and extending from the actuator, resi-lient sealing means positioned between the actuator piston and said orifice Wall for providing a pressure seal therebetween about the orifice and defining first and second areas of the actuator piston, a set pressure inlet tube secured to said wall bridge portion and extending into an axial bore in the actuator piston and in the thrust column, said thrust column and actuator piston being movable relative to the inlet tube, said thrust column having passage means communicating between the thrust column bore and the set pressure chamber, means for introducing a set pressure through said inlet tube, said bore and said passage into the set pressure chamber, said .set pressure acting on the actuator piston to urge the piston toward the wall, means for establishing a relatively high actuating pressure in the actuating pressure chamber to act on the actuator piston in a direction opposite to the yaction of the set pressure, ram means connected vwith the thrust column and `confronting said bolster means, a iioating reseating piston slidable in the actuator on the opposite side of the actuator piston from said Wall, an oil reservoir, conduit means communicating between the reservoir ymd the reseatin-g piston, pump `means for supplying oil under a reseating pressure from said reservoir through the conduit means to the reseating piston, electrically operable normally open iirst valve means in the conduit means between the reservoir `and the reseating piston, electrically operable normally closed second valve means interconnecting said conduit means and the reservoir, electrical means for opening said rst valve means to admit oil under the reseating pressure from the pump means to the reseating piston and to close said second valve means to prevent loss of reseating pressure to the reservoir, said reseating pressure urging Ithe reseating piston and the actuator piston toward said wall to prepare the actuator for operation and to move the ram means to its upward po-l sition, electrically operable normally open third valve means interconnecting said second actuator piston area and the exterior atmosphere, limit switch means operable upon movement of the ram means into said upward position to lose the rst valve means to stop the supply of oil under reseating pressure from Ithe pump means and to open the third valve means to relieve pressure trapped between the actuator piston and `said wall, `and to open the second valve means to release oil under reseating pressure from the reseating piston to the reservoir, electrically operable normally closed fourth valve means interconnecting -a source of triggering pressure with said second actuator piston area, and switch means responsive -to the pressure drop caused by said closing of the iirst valve means to close the third valve means to prevent loss of triggering pressure to the exterior atmosphere and to momentarily open the fourth valve means for a momentary application of triggering pressure to cooperate with the force of the actuating pressure on said first actuator piston `area to overbalance the forces on the piston to eliminate said pressure seal and release the actuating pressure upon said second actuator piston area, whereby the actuator piston is impelled trom said wall to impel said ram means to impact the bolster means.

References Cited in the tile of this patent UNITED STATES PATENTS

Claims

1. A HIGH ENERGY RATE FORMING MACHINE COMPRISING FRAME MEANS, ACTUATOR MEANS CARRIED BY THE FRAME MEANS, BOLSTER MEANS CONNECTED WITH THE FRAME MEANS, AN ACTUATOR PISTON SLIDABLE IN THE ACTUATOR AND CONFRONTING A WALL THEREIN, RESILIENT SEALING MEANS BETWEEN SAID PISTON AND THE WALL FOR PROVIDING A PRESSURE SEAL THEREBETWEEN DEFINING SEPARATE AREAS OF THE ACTUATOR PISTON, RAM MEANS CONNECTED WITH SAID ACTUATOR PISTON AND CONFRONTING SAID BOLSTER MEANS, MEANS ESTABLISHING AN ACTUATING PRESSURE IN THE ACTUATOR, A FLOATING RESEATING PISTON SLIDABLE IN THE ACTUATOR ON THE OPPOSITE SIDE OF SAID ACTUATOR PISTON FROM SAID WALL, AN OIL UNDER A RESERVOIR, CONDUIT MEANS COMMUNICATING BETWEEN THE RESERVOIR AND THE RESEATING PISTON, PUMP MEANS FOR SUPPLYING OIL UNDER A RESEATING PRESSURE FROM SAID RESERVOIR THROUGH THE CONDUIT MEANS TO THE RESEATING PISTON, ELECTRICALLY OPERABLE NORMALLY OPEN FIRST VALVE MEANS IN THE CONDUIT MEANS BETWEEN THE RESERVOIR AND THE RESEATING PISTON, ELECTRICALLY OPERABLE NORMALLY CLOSED SECOND VALVE MEANS INTERCONNECTING SAID CONDUIT MEANS AND THE RESERVOIR, ELECTRICAL MEANS FOR OPENING SAID FIRST VALVE MEANS TO ADMIT OIL UNDER THE RESEATING PRESSURE FROM THE PUMP MEANS THE RESEATING PISTON AND TO CLOSE SAID SECOND VALVE MEANS TO PREVENT LOSS OF RESEATING PRESSURE TO THE RESERVOIR, SAID RESEATING PRESSURE URGING THE RESEATING PISTON AND THE ACTUATOR PISTON TOWARD SAID WALL TO PREPARE THE ACTUATOR FOR OPERATION AND TO MOVE THE RAM MEANS TO ITS UPWARD POSITION, ELECTRICALLY OPERABLE NORMALLY OPEN THIRD VALVE MEANS INTERCONNECTING SAID SECOND ACTUATOR PISTON AREA AND THE EXTERIOR ATMOSPHERE, LIMIT SWITCH MEANS OPERABLE UPON MOVEMENT OF THE RAM MEANS INTO SAID UPWARD POSITION TO CLOSE THE FIRST VALVE MEANS TO STOP SUPPLY OF OIL UNDER RESEATING PRESSURE FROM THE PUMP MEANS AND TO OPEN THE THIRD VALVE MEANS TO RELIEVE PRESSURE TRAPPED BETWEEN THE ACTUATOR PISTON AND SAID WALL, AND TO OPEN THE SECOND VALVE MEANS TO RELEASE OIL UNDER RESEATING PRESSURE FROM THE RESEATING PISTON TO THE RESERVOIR, ELECTRICALLY OPERABLE NORMALLY CLOSED FOURTH VALVE MEANS INTERCONNECTING A SOURCE OF TRIGGERING PRESSURE WITH SAID SECOND ACTUTOR PISTON AREA, AND SWITCH MEANS RESPONSIVE TO THE PRESSURE DROP CAUSED BY SAID CLOSING OF THE FIRST VALVE MEANS TO CLOSE THE THIRD VALVE MEANS TO PREVENT LOSS OF TRIGGERING PRESSURE TO THE EXTERIOR ATMOSPHERE AND TO MOMENTARILY OPEN THE FOURTH VALVE MEANS FOR A MOMENTARY APPLICATION TRIGGERING PRESSURE TO SAID SECOND ACTUATOR PISTON AREA TO OVERBALANCE THE FORCES ON THE PISTON TO ELIMINATE SAID PRESSURE SEAL AND RELEASE THE ACTUATING PRESSURE UPON SAID SECOND ACTUATOR PISTON AREA, WHEREBY THE ACTUATOR PISTON IS IMPELLED FROM SAID WALL TO IMPEL SAID RAM MEANS TO IMPACT THE BOLSTER MEANS.