US3908429A

US3908429A - Hydraulic servo valve controlled cupping press

Info

Publication number: US3908429A
Application number: US434908A
Authority: US
Inventors: Martin M Gram
Original assignee: MTS Systems Corp
Current assignee: MTS Systems Corp
Priority date: 1974-01-21
Filing date: 1974-01-21
Publication date: 1975-09-30
Anticipated expiration: 1992-09-30
Also published as: JPS50114679A; GB1491143A; DE2502256A1

Abstract

A cupping press used for forming deep drawn cups that are made into drawn and ironed cans, and which includes an arrangement utilizing servo valve controlled hydraulic cylinders for the forming operation. Specially constructed multistage cylinders for the blanking and forming operations are operated with a closed loop control so that the cutting and forming operations are accurate and reliable.

Description

United States Patent 1 1 1111 3,908,429

Gram 1 Sept. 30, 1975 15 HYDRAULIC SERVO VALVE 2 522.450 9/1950 Jon-1115011 1. 72/432 CONTROLLED CUPPING PRESS 2,720,264 10/1955 Taylor CI a1. 2,843.070 7/1958 Berkley ct a1 72/349 [75] Inventor: M r in M- r m. p l 3.470.725 10/1969 Brown ct 111. 72/349 Minn 3.531.974 10/1970 Bicklcy 1 .1 72/455 3,702.55) 11 1972 H' lb' 1. 72'} [73] Assignce: MTS Systems Corporation, a d I 49 Minneapolis Primary E.\'aminerMilt0n S. Mchr [22] Filed: Jan. 21, 1974 Attornqv, Agent, or Firn1Duggcr, Johnson & 1211 Appl. No.: 434,908 Wcstma [57] ABSTRACT [52] U.S. Cl. 72/349; 72/350; 72/336; 72/432; 72/455 A cupping prc s5 used for forrmng decp drawn Cups [51] Int. Cl. B21D 22/22 1 3 99 9 m which [581 Field of Search 72/349. 350. 351. 432 :1 T i f l 72/455, 335. 336 3477 348 453 tro y rau1c cy 1n crs or t e orrnmg operanon. Spccmlly constructed mult1stagc cylmdcrs for the [56] References Cited blanking and forming operations are operated with a UNITED STATES PATENTS ClOSCCl loop control so that the cuttmg and formmg operations are accurate and reliable.

15681117 12/1935 Danly 83/637 2,411.503 11/1946 cuncstm a =11. 72/336 17 Clams, 10 Drawmg US. Patent Sept. 30,1975 Sheet 1 of 6 US. irawm Sept. 30,1975 Sheet 2 of6 3,908,429

U.S. Patent Sept. 30,1975 Sheet 3 of6 3,908,429 7 Sheet 5 of \H 45.5w m2? A wNN vmw wmN .WMN

Sept. 30,1975

US. Patent idea 923 Ar US. Patent Sept. 30,1975 Sheet 6 of6 3,908,429

cooLme PRESSURE HYDRAULIC SERVO VALVE CONTROLLED CUPPING PRESS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in deep drawing apparatus.

2. Prior Art In the prior art, various hydraulic presses have been utilized. The present device includes certain improvements to the actuators and to the arrangement of the load frame in which the actuators are mounted to increase the useability of the unit. The unit includes servo valve controls with feedback sensors to determine that each of the various stages of the hydraulic actuators completes its operation, before the next stage is energized.

SUMMARY OF THE INVENTION The present invention relates to hydraulic press devices used for the deep drawing of metal members formed into seamless cups as shown, for use as a first stage of manufacturing drawn and ironed cans.

A load frame formed into a number of different sections or modular units is provided. A die mounting block of the load frame can be separated for insertion, removal or servicing of the dies, and the frame sections are precisely relocated when the frame is restored to normal position. The arrangement of the two die portions (punch and female die) is such that the metal sheet from which the blanks are cut and formed is centered on a plane passing through the center line between the supports for the female die plate and the male actuators or punches so that any bending of the load frame will cause deflection of both the punch and die the same amount and the punch will be able to enter the female die even if the supports bow slightly.

The hydraulic actuators used comprise multistage cylinders which include one cylinder portion for cutting out the cup blank from a sheet of material, a clamping cylinder for holding the blank in position, and then a further cylinder for drawing the blank into cup shape through a die. In the combination, means are also provided in the actuators for passage of air which is used to blow off the formed cup from the punch.

The press is used with a plurality of actuators which are arranged to obtain the maximum utilization of the sheet of material being formed, and the press is easily adapted to different size of cups by providing means so that the hydraulic manifolds used with the actuators may be spaced different center distances apart if a different size cup is to be formed in the press.

In certain applications there are openings provided in the actuators for passage of cooling fluid to the punch. The servo valve controls include stroke or distance transducers to provide a stroke feedback signal for control. The transducers are mounted with the actuators to precisely and accurately sense the movement of the cylinder portion of the actuators during operation.

It is thus an object of the present invention to present a servo valve controlled hydraulic cupping press that is accurate and reliable. It is a further object of the present invention to provide a cupping or deep draw press which permits the accurate forming of the deep drawn It is a further object of the present invention to present multistage hydraulic actuators which have blank cutting, blank hold down, and deep drawing capabilities. Other objects will be apparent as the description proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view of a load frame for the hydraulic cupping press made according to the present invention and illustratively showing actuators and dies installed therein;

FIG. 2 is a side elevational view of the device of FIG.

FIG. 3 is a vertical sectional view of a typical actuator used with the cupping press of the present invention;

FIG. 4 is a vertical sectional view of a modified form of the actuator used in the present invention;

FIG. 5 is a fragmentary enlarged vertical sectional view taken as on line 55 in FIG. 2;

FIG. 6 is a fragmentary enlarged sectional view of a typical assembly between hydraulic manifolds used with actuators of the present invention showing the means for attaching tubes between adjacent hydraulic manifolds to permit changing the center distances of the actuators;

FIG. 7 is a schematical representation of a typical control circuitry shown in combination with a computer control for the device of the present invention;

FIGS. 8 and 9 are schematic representations of typical timing cycle for the blanking and draw cylinders, respectively, of the present invention; and

FIG. 10 is a part schematic representation of a typical hydraulic actuator used with the press of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The hydraulic cupping press illustrated generally at 10 comprises a load frame 1 1, which as shown as a rigid frame made up into indivualized sections that will permit, as will be explained, separation of the sections for maintenance and in case a jam occurs.

The frame 11 has a lower cross frame member 12, a center punch and die section 13, and an upper cross frame member 14. The upper and lower cross frame members or supports 12 and 14 are spaced apart to form the open die section 13 for the tools and including the actuators used in the cupping or forming process. The upper and lower cross frame supports 12 and 14 are separated by spaced

side walls

15, 15.

Cross frame members

14 and 12 as can be seen are deep in vertical dimension. The

cross members

12 and 14 are clamped against the walls 15 with four hydraulic cylinders illuswith precise feedback control of the actuators.

trated generally at 16.

The cylinders 16 are mounted onto the top of the upper cross support member 14. The cylinders 16 are double acting hydraulic cylinders controlled through suitable valves, from a suitable hydraulic pressure source. The cylinders 16 each have an elongated rod 17 controlled by an internal piston, and the rods extend through provided openings in the ends of cross frame support 14, the walls 15, and the cross frame support 12, down to near the bottom of the support 12.

As shown in FIG. 5, the lower end of each of the rods 17 is mounted in a nut so that the rods will be held with respect to the support 12, but are not threaded directly to the support 12. A separate nut 18 is threaded onto the end of each of the rods 17, and cap screws 19 are used for attaching the nuts 18 to the base 12. In this way, the rods 17 can be retracted by operating cylinders 16 to very tightly clamp the walls and the upper and lower cross frame supports 12 and 14 together. The walls 15 will be under a compressive force generated by the cylinders 16. Likewise, when hydraulic pressure is provided in the cylinders 16 to extend the rods 17 a greater distance from the cylinders, the nuts 18 and cap screws 19 will carry the load so that the upper cross member 14 and the lower member 12 will be forced apart or separated.

As shown in FIG. 2, the walls 15 have window openings 22 defined therein, and long cap screws 22A may be used for attaching the walls 15 to the upper cross frame member 14. This means that when the cylinders 16 are extended so that the rods 17 separate the upper and lower cross members the walls 15 will move with the upper cross member 14. The walls 15 could be attached to the lower cross member 12 if desired. A suitable upper tooling locating plate 23 is mounted to the upper cross frame member 14 and positioned between the walls 15 and the upper cross frame member. Likewise, a lower main tooling support plate 24 can be mounted underneath the walls 15 and on top of the lower cross frame member 12 and clamped between the walls 15 and the cross frame member 12. The upper tooling locating plate 23 and the lower tooling support plate 24, as well as the walls 15 may be precisely made for accurate location of the tooling. Dowel pins can be used for locating the tooling plates in position.

The lower locating plate 24 is held to the lower cross member 12 with suitable cap screws 25 so that the lower tooling plate 24 will move or stay with the lower member 12 when the rods 17 are extended.

Because the alignment between the upper draw punch members which are carried by the actuators used with the hydraulic cupping press, and the lower die members is very critical, and a minimum amount of tolerance is provided, it is important that if the hydraulic cylinders 16 are actuated to separate the upper and lower member, as may be done when a jam up occurs in the tooling, the parts are repositioned accurately. In order to insure that the upper and

lower cross members

12 and 14 and the walls 15 will assume the proper position, suitable guide pins are provided. The guide pins 30 have a shaft portion that is fixed to the walls 15, as shown there are two pins on each of the walls 15. The pins have a radiused end 30A that is precisely made fits with very close tolerance inside a hardened steel sleeve 31 that is mounted in the tooling plate 24. If after separation of the cross members the assembly is to be reclamped together, the pin ends 30A will be slidably guided inside the hardened sleeves 31. The pins insure that the walls 15 are precisely located with respect to the tooling plate 24 and because the walls 15 are clamped with the cap screws 22A to the upper cross member 14, the

cross frame members

12 and 14 will also be precisely realigned when the cylinders 16 are actuated to clamp the frame parts together. The radiused pin ends 30A will provide guides to reposition the walls 15 and lower cross member 12 even if the parts shift a significant amount when separated.

The lower cross frame member 12 can be mounted on supports 32 if desired.

The lower tooling plate 24 is designed to mount the blanking and drawing dies. There are a plurality of conveyor belts illustrated generally at 35 also provided below the dies. The conveyor belts 35 are used in a normal manner to receive formed cups from the dies. A formed cup is shown generally at 36 on the upper length of each of the conveyor belts. The conveyor belts may be mounted over end rollers in a conventional manner and they transport the formed cups 36 to a desired location. A die locating plate 37 is rigidly supported spaced from the lower tooling plate 24 by suitable supports 38 which rigidly support the entire assembly and are located between the conveyor belts. There is one conveyor belt for each of the dies used, to receive the formed cups from the die. There are usually two transverse rows of dies on the machine which are staggered to maximum utilization of material. For purposes of illustration, only one row of four dies is shown in FIG. 1. A second row of actuators is shown in FIG. 2. One row would be adjacent the front of the machine and one adjacent the rear. The actuators 40 are mounted to the upper tooling locating plate 23 and each actuator has a hydraulic manifold indicated generally 42 and servo valve controls illustrated generally at 41 mounted thereon. The manifolds and valves are connected to a supply of fluid under pressure and to return lines which are connected to the servo valve controls 41 through the manifolds 42. There is one of the manifolds 42 for each of the hydraulic actuators 40, and each of the manifolds receives pressure from a suitable pressure line 43, and is also connected to a return supply line 44. Suitable accumulators illustrated generally at 45 are utilized at the servo valves for eliminating pressure surges or spikes, and main supply and draw accumulators illustrated generally at 46 also can be used in the hydraulic system as desired. A schematic representation of a typical actuator and manifold is shown in FIG. 10 and will be explained subsequently.

The manifolds 42 are connected together from a common supply and the manifolds are connected directly to their respective actuators. When the center distances of the actuators 40 are changed because of a differing size cup being formed and thus a different size die being necessary, the manifolds 42 can be moved along with their actuators because of the connection pipe configuration between adjacent manifolds. Further, because of a necessity at times to service the hydraulic components, the manifolds can be quite easily removed individually by use of the connecting pipes as shown in FIG. 6. These pipes comprise a tube member 48 which slides into an opening in a first hydraulic manifold 42A, and the tube 48 has a flange 49 at its outer end. The flange bolts against the adjacent manifold 42B and opens to the desired port in the manifold 428. All tube connections between adjacent manifolds use the flanged tubes, and thus when one of the manifolds is to be disconnected from other manifolds, for example when the manifold 42A is to be disconnected from the manifold 42B, the cap screws holding the flange 49 in place can be removed, and any other flanges attached to the manifold 423 can also be released so that the tubes and flanges can be removed along with the manifold 42A. The flange 49 can be sealed with an O ring flat against the surface of the manifold 42B, if desired.

If the center to center distance of the actuators for

manifolds

42A and 42B is to be changed, the amount that tube 48 is protruding into manifold 42A can be changed without affecting the hydraulic pressure seal of the tube. An 0 ring 50 is used for a seal so the tube 48 can slide into and out of the manifold 42A to permit the distances between the manifolds to be changed.

The hydraulic connections between the manifolds include the tube 48 that is inserted into one of the manifolds and a flush fitting flange on the adjacent manifold which can be removed merely by unscrewing the cap screws holding the flange in place. Of course a small protrusion of the tube 48 at the flange end into manifold 428 could also be tolerated if desired because the tube 48 could be slid inwardly into the manifold 42B 21 short distance before removing the manifold 42A. This would permit a small projection to clear the manifold 423.

The servo valve controls are well known, and will be operated by controllers to actuate the actuators 40 to carry out the cutting of the cup blank from a sheet of material and the drawing or forming of the blank into cup shape.

Each of the servo valve controlled actuators 40 includes a stroke feedback transducer to the servo valve controller so that the movement in the actuators is controlled by a direct feedback signal. The movement of the actuators with relation to the dies held by the lower die support plate 37 is thus very precise. The individual dies are illustrated generally at 52. The upper surfaces of the dies 52 lie along a center plane illustrated generally at 53. The plane 53 is midway between the lower edge of the cross member 14 and the upper edge of the cross frame member 12. If there is any bending or bowing of the

cross frame members

12 and 14, as shown in greatly exaggerated scale by the dotted lines in FIG. 1, the center lines of the die and the actuators will be angled or cocked the same amount, so that the center lines will intersect even if there is some bowing of the supports. Thus the draw punch will still be positioned to properly enter the die opening. This is extremely important when very close tolerance punches and dies are used, and in particular when six or eight dies will be operated at once, the loads on the cross supports can become quite high. The bending of the cross members is therefore made equal to insure proper operation even when under load.

Referring to FIG. 3, a typical actuator 40 is shown in cross section. While many of the internal passageways for hydraulic pressure and return flows are not shown, these passageways are formed in the cylinder body itself and can be done in any convenient manner. The only criteria is that the passageways do not intersect or cross, and that they do not intersect any bolt holes or the like. Thus, the formation of the necessary passageways from the manifold 42 for the respective cylinders is believed to be well within the skill of the person working in the art, and for sake of clarity the passageways in many instances are omitted. The pistons and piston chambers are circular in cross section.

The actuators 40 in the form shown in FIG. 3 include a main body member 60. The body member 60 includes a planar external face for mounting the manifold 42 in position, for pressure and return flow to the various ports and passageways of the actuator. The upper end of the body 60 is mounted to the support plate 23. Because of the close tolerances involved, as shown, the body member 60 has a part spherical locating stud or ball 61 thereon. The stud 61 has a part spherical outer surface, that fits tightly with an opening 62 in the plate 23 so that the cylinder body 60 will be precisely located but yet can be guided into place. A plurality of studs 63 hold the cylinder tightly against the surface of the plate 23 to positively lock the body in position.

The main body 60 includes a cylindrical lower portion 60A, below the surface where the hydraulic manifold is connected, and a cylindrical sleeve 64 is slidably mounted over this lower portion. The sleeve 64 is slidably mounted over

annular bearings

65 and 66, which are spaced in longitudinal direction of the main body member. The lower bearing 66 is mounted onto a ring 75 that is fixed in place on the lower end portion 60A of the main body member. The sleeve 64 slides with respect to the body member, on the

bearings

65 and 66. An axially extending groove 64A may be provided to fit onto a fixed guide 64B to prevent the sleeve from rotating during operation.

The sleeve 64 includes an annular inwardly extending ledge 67 which forms, in connection with a mating shoulder on the body member 60 and the end of a ring 75, a double acting piston extending annularly around the reduced diameter lower portion 60A of the main body 60. The annular piston 67 is sealed on the outer diameter of the main body with an O ring 74. A chamber 68 is formed between the shoulder of the main body 60 and the upper surface of the ledge or piston 67, and suitable passageways are open from the associated hydraulic manifold to the chamber 68. When fluid under pressure is provided to the chamber 68 a force will be developed on the piston formed by the ledge 67. Cylinder return force is provided by fluid under pressure supplied to a chamber 78 between the lower surface of ledge 67 and the upper end of the ring 75.

An annular blank cutter 70 is used for blanking out the blanks for the cups to be drawn from a sheet of metal in combination with the blanking die ring illustrated generally at 71. The cutter 70 is made in three sections including a first ring 70A contacting the lower end of sleeve 64, a second ring 708 that clamps against the first ring and a third ring 70C clamped to the sec ond ring and having an annular cutting edge 72. The blanking die 70 will move down when pressure is supplied to chamber 68, and the cutting edge 72 will engage a sheet of material in the cutting die above a die ring 71. The die ring 71 as shown will move down wardly along guide studs 73 and as the cutting die 70 moves downwardly, the cutting edge 72 will shear off the material to form a round blank of material for drawing the cups and shown at 98A in dotted lines.

The ring member 75 is slidably sealed with respect to the outer surface of the lower portion of the sleeve 64 with a suitable O ring 76, and is held on the main body 64 with a plurality of cap screws, one of which is shown at 77. A suitable passageway is open to the chamber 75 for hydraulic flow, and as can be seen, the ring has an annular chamber or recess 78A which forms part of the chamber 78. I

The ring 75 supports a rod guide bushing 80 in place within an interior opening 81 in the main body member 60. The opening 81 as will be explained, forms the main draw cylinder, and the rod guide bushing 80 supports the rod 82 at its lower end. The rod 82 has an upper piston portion 83 at its upper end that is also slidably mounted in the opening 81. The piston portion is ring shaped, with a central opening that aligns with a central opening 84 in the rod 82. The piston portion has a larger surface area on the side thereof facing toward the base than on the return side.

A transfer tube 85 that is fixed at its upper end at a provided receptacle in the main body 60 is slidably mounted through the central opening of the piston por tion 83 and extends into the opening 84 of the rod. An ring 86 in the piston portion 83 slidably seals against the outer surface of the transfer tube 85. The piston forms a main piston chamber in opening 81, and a portion of the piston chamber is indicated at 87 to show where pressure for drawing the blank into a cup is applied to the piston.

The transfer tube is used to isolate the interior passageway 90 of the transfer tube and the lower portion of opening 84, on the rod side ofO ring 86 from the hydraulic oil which will be supplied to the chamber 87. The transfer tube also surrounds the linear displacement transducer indicated at 91. The displacement transducer is fixed at its upper head end 94 to the stud portion 61 with suitable cap screws and fittings. The linear displacement sensor has a movable rod 92 that moves with respect to the main portion thereof to sense displacement, and the rod 92 is attached as at 93 to the end of the actuator rod 82. The rod 92 is adjustably mounted, for zero adjustment, and can be positioned as necessary for obtaining a proper indication of movement of the actuator rod 82 with respect to the body 61. Movement of the rod 84 will be sensed by movement of the rod 92 with respect to the main body of the linear displacement sensor 91. Suitable connections are provided for providing an electrical signal from the displacement sensor 91 to the control circuitry proportional to the displacement of rod 84 from its retracted position.

The transfer tube 85 has a head end indicated at 94, with suitable passageways 95 leading to an air passageway 96 which is connected to a suitable source of air under pressure. The lower end 84A of chamber 84 of the actuator rod is open through a number of small passageways 97 to the center of a drawing punch 98 that is attached to the actuator rod 82 with suitable cap screws 99. Air under pressure coming through the transfer tube inner passageway 90, and

passageways

84A and 97 will be used to blow off a can or cup after it has been formed by the drawing die.

The sleeve portion of the actuator which operates the blanking or cutting edge 72 has been described, and the punch 98 for drawing the blank into a cup shape has also been shown as being attached to the main actuator rod 82 driven by the piston 83. The return side of the piston 83 is defined by the area of the annular surface indicated at 100. A return pressure passageway opens to the enlarged area of the opening 81 adjacent to the sleeve 80, so that return pressure can be exerted on piston 83 when the rod is to be retracted after the forming operation. The differential in area between the two surfaces of the pistons is made for a more rapid return stroke of the piston. The piston areas are selected to make the pressure drop across the valves for the main drawing operation equal in both directions of operation of the actuator rod. For example, at a typical flow rate of gpm in the system and a regulated pressure of 3,000 psi, if the forces required by punch 98 to draw the cup is developed with 2,500 psi, there will be a 500 psi pressure drop across the servo valve. Thus, the return piston size represented by surface 100 can be designed to cause a drop of 500 psi across the servo valve between the chamber 87 and drain with full pressure acting against the surface 100.

During the cup forming operation, it is necessary that the blank of material be retained by a hold down force, so that a controlled amount of the material being formed is permitted to slide into the draw die while the drawing operation is underway. The hold down cylinder is operated in combination with the ring 75. An annular (ring type) hold down piston 101 is shown in cross section, and a first end thereof fits into a recess in the sleeve 75, and is sealed with large annular 0 rings 102. The piston 101 is held in place on the ring with suitable cap screws 103.

The piston 101 fits into an annular chamber 104 which forms a hydraulic cylinder in a ring 105 that aetuates against the hold down pad 105A. The ring 105 and hold down pad 105A surround the draw die 98, and they are slidably movable with respect to the annular piston 101. 0 rings 106 seal the lower portion of the piston with respect to the chamber 104. A suitable hydraulic passageway is provided to the lower end of the piston 101, for example as shown in dotted lines on the right side of FIG. 3, and the passageway leads to the hy draulic service manifold for the actuator. Hydraulic fluid under pressure can thus be supplied to chamber 104 and pressure in the chamber will force the ring 105 and pad 105A toward the mating portion 1 10 of the die set 52. The two

parts

105 and 105A work together to hold down the cut blank during the drawing operation. The pressure in chamber 104 is at a regulated level so that amount of holding or clamping force on the blank is controlled. This will result in the desired drawing and forming of the blank to uniformly distribute the metal in the wall of the cup being formed. Also, when the edge of the blank has been pulled inwardly so that only a small flange is left (for example a flange of A inch or so), the pad is lifted off to prevent the pad from ironing down the edge of the blank as the last portion is pulled into the die.

The ring 105 has a lip portion 111 that forms a shoulder that mates with an annular shoulder 1 12 on the ring 70A for interaction of movement between sleeve 64 and ring 105. In addition, the pad 105A has an annular ledge or lip 113 that is positioned to abut against downwardly facing shoulder 114 of the ring 70A and hold the cutter 70 from moving to its full down position if the spacing between the blank support of the die and the pad 105A is too great. This can occur if two pieces of metal, for example, happen to getjammed between the holding pad 105 and the support 110. Such double thickness of metal could cause serious misalignment of the drawing die and thereby damage the dies. By having the support 113 engage the cutter 70, the cutter 70 will not go to its full down position if there is more than one thickness of metal. A limit detector switch indicated schematically at 223 (and also in FIG. 7) comprises contacts which close only when the cutting edge goes to its full down position. The detector is controlled by signals from a cutter displacement transducer shown in FIG. 7, and when the cutter is held from full travel by annular ledge 113, the limit detector senses the transducer output and does not close the switch 223. The lack of closing of switch 223 comprises a signal which stops further press operations until the malfunction is corrected. When the cutter 70 is in its full down position and finished cutting the blank shown schematically in dotted lines at 98A then the limit switch or contacts 223 will be closed to indicate that the blank has been cut. The contact closing is used as a signal to continue the drawing operation.

The hydraulic cylinder formed by piston 101 and chamber 104 is single acting and as will be explained is under pressure urging it downwardly toward the die. The pad 105A and ring 105 are retracted and held by the force of the blanking cylinder formed by sleeve 64 and piston 67. When the cutter is retracted by pressure in chamber 78, shoulder 113A on ring 70B engages ledge 113 to force the hold down pad to retract. The hold down pad is constrained only by the annular shoulder 113A and the surrounding cutter 70, and the hold down piston and cylinder have sufficient clearance so that the pad can rock or tilt slightly with respect to piston 101. Slightly irregular blanks may thus be held evenly and the pad can adjust to such malfunc tions as doubling of the sheet on one side without applying bending loads to the actuator. The hold down pad will tilt from a horizontal plane several degrees, for example 2 to degrees about any diametral line or axis.

Suitable switches may be utilized with the unit to indicate when the sleeve 64 and pad 105A are fully retracted. These switches are shown schematically in FIG. 7 and are conventional limit detectors which operate from the signal of the associated stroke transducer (LVDT). The stroke transducer 91 signal indicates the position of the punch 98 in relation to the die opening 115 in support 110. When the signal is at a certain value the limit detector closes the switch contacts. After the punch, cutter and hold down pad have been retracted, the sheet of material can be advanced and the cutting and drawing operation repeated.

When the actuator rod 82 and punch 98 have completed their stroke, or at any other appropriate time, air under pressure is introduced by suitable valves into passageway 96 and thus through passageway 90 on the interior of the transfer tube, to passageways 97 to the interior of the formed cup to blow the cup off the punch 98.

The O ring 86 keeps the hydraulic fluid (oil) in chamber 87 acting on piston portion 83 isolated from the air on the interior of the transfer tube.

It should be noted that as the actuator rod extends a greater portion of the passageway 84 is exposed as the rod slides down along the transfer tube. Thus the volume of air in the opening or passageway 84 is larger than when the transfer tube is telescoped into this passageway. On the return stroke of the actuator, which is relatively rapid, the transfer tube will displace some of the air in the passageway 84 causing compression of the air and raising the pressure acting on the formed cup covering punch 98 above the pressure of the air source. This extra pressure created on the return stroke of the rod 82 is an-aid in insuring that the formed cup will be popped off the punch and dropped onto the aligning conveyor belt 36.

The cavity volume on the interior of

rings

75, 105 and 105A also will change during the strokes of the punch. An atmospheric bleed passageway 116 is provided to permit air to flow in and out as the punch is reciprocated.

A feature of the actuators shown, which are multistage actuators, that is, more than one hydraulic cylinder on each actuator, is that the bending resistance of the blanking actuator is made as high as possible within the diameter limitation imposed by the size of cup. This is to minimize side deflection which can damage the cutting dies when a malfunction causes cutting to occur on one side only of the die. This is accomplished by having the separate cylinder for the cutting die and hold down pad formed at the end of the main body farthest from the support end. The main body is stiffest near the base and then is stepped down for the auxiliary cylinder, at locations spaced from the base where bending moments cause less deflection at the die.

Additionally, widely spaced bearings and 66 adequately support the sleeve 64, which forms the movable portion of the blanking cylinder.

Referring specifically to FIG. 4, a second form of actuator 40 is illustrated which is used in certain instances where hydraulic oil flow is required through the punch for cooling.

The actuator in this form of the invention is illustrated generally at and includes an actuator body 126 that has a surface 127 on which the manifold 42 for fluid pressure and return is mounted. The flows in turn are controlled by the servo valves. The manifold surface 127 includes the necessary ports and passageways for aligning with the passageways in the manifold. The actuator 125 is mounted with a radiused locating end stud 128 as in the previous form of the actuator, and would be bolted up against the locating plate 23.

An outer sleeve 130 comprising a blanking cylinder is slidably mounted over a cylindrical lower portion 126A of the body 126, and is sealed with respect thereto with suitable 0 rings and guided thereon with suitable bearings indicated at 131 and 132. The sleeve 130 carries a cutting edge die Iocator ring 133 (which corresponds to ring 70A of FIG. 3), and although the cutting edge die is not shown, it is the same type of die as that shown in FIG. 3. The sleeve 130 has an inwardly extending ledge 134 that forms a piston for the blanking cylinder, and this ledge or piston is sealed with respect to the reduced outer diameter of the body member 126. A first pressure chamber 135 is formed between the upper surface of piston 134 and a shoulder formed in body member 126. The chamber 135 opens to a passageway on the interior of the body 126, so that fluid under pressure may be supplied to chamber 135 to force the sleeve 130 away from the base of the body member or in other words axially downwardly.

The return cylinder chamber 136 for sleeve 130 is formed between the lower surface of the ledge 134 and the upper surface of an annular ring 137 that is fixed to the body member 126. The ring 137 surrounds the lower portion of the body member 126 and may be held in place with suitable cap screws 138. The ring 137 also has an inwardly extending ledge that surrounds a main piston or actuator rod 142 and which supports a sealing and bearing sleeve 140 in position at the lower end of a central inner axially extending opening indicated at 141 defined in the body member 126. The bearing sleeve 140 is held against axial movement, but slidably guides and seals against the cylindrical rod 142 that is mounted in the opening 141.

The rod 142 is formed into several sections of differing diameters and has a reduced cross, sectional size upper portion indicated at 142A that forms a shoulder 143 with the maximum diameter portion 142C of the piston rod. The maximum diameter portion 142C forms the piston and shoulder surface 143 in the piston surface used for the drawing operation. There is a second shoulder 144 defined on the rod where the rod reduces to the size which passes through the sleeve 140.

The shoulder 144 forms the return piston for the actuator rod.

A guide sleeve 145 is mounted inside the central opening 141 above the shoulder 143 of the rod, and abuts against a locator and fastening block 146 that is fixed at the upper end of the body 126 on the interior of stud 128. The sleeve 145 has an interior opening through which rod portion 142 extends. The sleeve carries suitable rings and bearings for slidably sealing and guiding the rod as it moves in axial direction. The outer surface of the sleeve is also sealed with 0" rings on the inner surface of opening 141.

The stop or locator block 146 is mounted in the upper end of the cylinder and mounts a pair of transfer tubes 150 (only one is shown, but the other is mounted in the same way), which are open to a passageway 151 for the inlet of cooling fluid for cooling the die set used. The cooling fluid connection passageways also will pass through the associated manifold. The cooling fluid passes through the interior of the first transfer tube into a first longitudinally extending opening 151A defined in the rod. The transfer tubes are sealed with suitable 0 rings 152 so that as the rod 142 is moved axially in the opening 141 by hydraulic pressure the hydraulic oil inside the opening at 141 above the shoulder 143 will not be permitted to contaminate the cooling fluid in passageway 151A, and vice versa. The passageway 151A is open through a suitable port to the drawing punch, only the upper part of which is shown in FIG. 4, at 157 but which mounts onto the lower end of the rod indicated at 1428. The fluid passes through passageways in the punch 157 and a small sealable connector 1518 can be used to connect the punch passageway to a return passageway 151A. Mating openings in the die and rod could be used as well. The passageway 151C is a coolant return passageway which would lead to a transfer tube mounted as shown in conjunction with passageway 151A. The return coolant will also be discharged through the manifold to a reservoir.

The upper locator plate 146 also fixedly mounts a stroke transducer indicated at 154, and the stroke transducer has a movable rod 155 which is attached to the lower end 1428 of the actuator rod. The rod 155 moves with the rod 142 as it extends or retracts and the transducer provides a signal along the line indicated at 155A to the control circuitry. The stroke transducer is mounted in an interior longitudinal passage 156 which is connected by a suitable passageway to the end of the rod 142B to the interior of the punch. The passageway 156 is open to the interior of sleeve 145 and through a port 156A to a passageway 156B which would connect through a valve to a source of fluid under pressure used to blow a formed can off the punch after the forming operation.

A passageway 158 is defined in the body member 126 and mates with another passage 158A defined in the ring 137. This passageway then leads to an opening surrounding the rod 142, which is the area into which the draw punch retracts on the return stroke of the rod. The passageways 158 and 158A provide a vent to atmosphere for air flow during the draw and return strokes of the punch. A suitable connection 159 may be used to connect the passageway to conduits leading to atmosphere.

A passageway 160 is defined in the actuator and leads to a suitable drain port on the surface 127, and fluid trapped between 0 rings and seals may be bled off through passageways such as 161 leading to a groove 161A in the support ring a small passageway 162 leading to an annular passageway 162A that in turn is open to a passageway 162B above a bearing 162C; a passageway 163 leading to an annular passageway 163A between the support bearings at the upper portion of the sleeve 130; and a passageway shown fragmentarily at 165 which leads to an annular passageway 165A to provide fluid drain for the lower bearings for the sleeve 130 as well.

It should be noted that the passageway 160 does not connect with the passageway shown at 169. The passageway 169 is for carrying hydraulic fluid under pressure to operate the hold down pad for the material being drawn. In this particular form of the invention, an annular ring 170 is provided with a center opening in which the draw die will be positioned, as shown, and ring 170 is mounted in an interior opening in the ring 137 at the lower end thereof. Suitable cap screws can be positioned around the periphery of the ring 170 to hold it in position. The ring 170 has the lower portion of its outer peripheral surface recessed away to form an annular chamber 171 in connection with the inner wall of the ring 137. The chamber forms a hydraulic cylinder to which the passageway 169 opens. The hold down pad 172 is machined to have an upwardly extending annular ring type piston 173 and the ring 173 has recesses defined at its upper end to form grooves for 0 rings 174 which are annular and extend all the way around the reduced area portion of the ring 170. The 0 rings seal against the side surfaces defining the chamber 171. The supplying of fluid under pressure to the passageway 169 will cause a force acting against the upper surface of the ring 173 tending to push the hold down pad 172 downwardly against the mating die part, which is shown in connection with the cylinder FIG. 3, to hold the sheet of material from which the blanks for the cup are cut, and to hold the blanks firmly in the die during the drawing operation. The hold down pad 172 has a shoulder 175 that engages a mating shoulder 176 on the member 133 for the cutting blade which moves with the sleeve 130. The shoulder 176 lifts the hold down pad on the return stroke of sleeve 130. The chamber 171 is a single acting cylinder and is useful to force the hold down ring 172 in one direction to hold the blank during forming under a controlled pressure. The ring 173 and pad 172 are again free to cock slightly because the pad is retained only by the member 133.

The cylinder or actuator 125 shown in FIG. 4 is con trolled in much the same manner as the one shown in FIG. 3, and suitable cooling fluid can easily be supplied to the draw die in this form of the actuator. The use of the transfer tubes again permits isolation of two fluids, namely the cooling fluid and air. The air on the interior of sleeve 145 is isolated from the cooling fluids by 0 rings 152 which are carried by rod 142 and slide along the respective transfer tubes.

Suitable connections are made so that fluid under pressure is supplied to the cylinder area 135 when the cutting is to be accomplished, and at the same time fluid under pressure would be supplied to the passageway 169 to push the hold down ring 172 down against the material in the die, to hold it securely. The stop member for preventing the cutting ring from fully seating if a double piece of metal is in the die is also incorporated into the die set, as shown in connection with FIG. 3, to provide a safety function.

Suitable limit switches are utilized to determine the seating of the cutter cylinder or sleeve 130 in its lowermost position when the cut is done and may be used to indicate full retraction of the sleeve 130.

In FIG. 4, a small tab 178 is shown attached to the rod 142 at the upper end, and this projects into a slot 179 defined in the sleeve 145 to keep the sleeve properly positioned with respect to the rod and prevent it from rotating in use. Likewise, the slot 180 is also used for a locating finger to prevent the outer sleeve 130 from rotating. The locating finger in slot 180 can be fixed with respect to the load frame in any desired man ner.

Referring to FIG. 10, a schematic diagram of the hydraulic cupping press is shown just for sake of clarity. While the schematic showing is not of any particular actuator, it would resemble perhaps most closely the actuator shown in FIG. 4, although separate numbering will be utilized. The actuator indicated generally at 300 comprises a main body 300A which has a manifold 30] attached thereto, and it is this manifold 301 that can be used with the connection tubes between adjacent manifolds on adjacent actuators for common drain connections, air connections and the like. Thus the manifold 301 is a representation of manifolds 42. An outer cylinder sleeve 302 is mounted on the main body 300A and defines cutting and return cylinders 303 and 304 for carrying the blank cutter. A hold down pad 305 is pro- 7 vided, and has a piston ring 305A operating in a cylinder 306 defined in the actuator body. A central rod 310 has a piston 310A thereon operating in a chamber and dividing the chamber into power and return

cylinders

311 and 312, respectively. The rod 310 is slidably mounted as shown, and carries the draw punch illustrated at 313 at the lower end thereof. The transfer tubes 314 and 315 are slidably sealingly mounted in passageways in the rod 31 for cooling oil passageways. A passageway 316 leading from tube 314 connects an aligning passageway in the manifold 301 to carry coolant to the rod 310 through the passageway in the rod, and through a passageway or passageways 317 in the punch 313, and back out through a second passageway in rod 310, through tube 315 and through passageway 318 in the actuator and manifold to the source of cool- An air passageway 319 in the center of rod 310 transfers air from the connecting passageways 319A in the actuator and manifold, and the passageway for air is formed through the punch 313 so that the air can be used for blowing a formed cup off the punch.

A drain passageway 320 is connected on opposite sides of the seals, as previously explained, and leadsjust to a drain through a connecting passageway in the manifold. The cylinder 306 is connected to a passageway 321 that leads to an accumulator 322A and to a pressure regulator assembly 322 which permits the adjustment of the pressure in the hold down pad cylinder 306 to a desired level so that the drawing is precisely controlled and the blank being formed will slip out from the hold down pad during the forming operation at a desired force to accurately form the cup.

The need to supply oil from a pressure source on each cycle is eliminated by the accumulator 322A which supplies oil under pressure as the hold down cylinder is permitted to extend and absorbs the oil as the hold down cylinder is retracted by action of the blanking or cutting cylinder. The accumulator 322A is large enough so only a small change in accumulator pressure occurs during each cycle. The accumulator pressure used to constantly urge the hold down pad toward a blank is used in the actuators of FIGS. 3 and 4 as well. A first servo valve 325 is connected to

passageways

326 and 327, respectively leading to the cylinders 303 and 304. This operates the cutting or blanking cylinder sleeve 302. A second servo valve 330 is connected to

passageways

331 and 332, respectively which lead to the cylinders 31 1 and 312, respectively for the main actuator rod. Cylinder 311 is the draw cylinder. The servo valves have suitable accumulators shown in FIG. 1, in the input sides, and on the drain sides as desired. The connections leading from the manifold 301 and the servo valves can go through a hydraulic distribution manifold, and then to the respective sources of cooling air, cooling fluid, and the various drains necessary.

Referring to FIG. 7 a simplified schematic diagram of the controls used is shown. A control computer 200 is used for monitor control in the cupping process, and each of the individual actuators are operated simultaneously and controlled separately. The computer 200 gives start and stop command signals in response to closing and opening of certain circuits, and for example if the start circuit is initiated, a pair of contacts 201 will be closed by the computer indicating that an operation cycle is to commence. It should be noted that each actuator has a control for the blanking cylinders and a separate control for the draw cylinder. Only three channels are shown but, of course, controllers for each actuator may be added as desired. The signal on line 202 is used to energize servo valve controllers for each actuator indicated generally 203. The controller includes a wave form generator 204 and the wave form generator is initiated by the signal from line 202 as shown. The wave form generator has an up rate adjustment 206 and a down rate adjustment 206A to provide the necessary adjustment to supply the proper form control signal for the valves in a known manner. The output signal is connected to span adjustment 205, and to a summing junction 205A where the wave form generator output signal is summed with the signal from set point device 207, and also from a signal carried along line 208 from a feedback signal generated by the stroke transducer 208A that is connected to the blanking

cylinder

64 or 130. While the transducer was not shown in FIGS. 3 or 4, such a transducer is connected to detect and deliver a signal which is a function of the stroke of the blanking cylinder as is well known. The stroke transducer feeds a signal through a signal condi tioner 209 of usual design. An error detector circuitry indicated at 210 can also be used, and this can have an indicator light 211 that is lit up if an error is detected in operation. The output of the summing junction 205A is fed through a gain control 212 to an input of a valve amplifier 213. The valve amplifier 213 also has a second input from a stabilizer circuit 214 which operates from a signal to the conditioner 209 of the stroke transducer, and then an output signal is fed along the line 215 to the respective servo valve 41 which is controlled in accordance with the wave form generator signal and feedback signal developed by the stroke transducer. This is a servo control loop used for operating the actuators. The servo control components are well known.

Limit detectors are provided as previously explained and are shown schematically in the controller. The limit detectors are activated by the signals from the stroke transducers, and can be adjusted in a known manner by means of potentiomcters to be activated at any desired stroke position of the respective cylinders. A limit detector indicated generally at 220 comprises a set of contacts 221 which will close to give a signal when the blanking cylinder portion (the sleeves 64 and 130) of the actuator is at its upper limit. This signal is fed back along line 222 and must be present before the contacts 201 are closed.

The blanking or cutting cylinder of the actuator is operated by the associated servo valve to cut the blank, and the hold down pad will extend with the blanking cylinder. When the blank is cut contacts or switch 223 of limit detector 220 will be closed, which will provide a signal along the line 224. The lines represented may comprise the necessary number of wires to carry the signals delivered. The lack of a signal from contacts 223 will prevent further press operation because this would indicate some problem with the hold down pad; for example, two pieces of metal under the hold down pad, so that switch 223 did not close, as previously explained.

The individual controllers 203 are provided separately for each of the different actuators. In the form of the press shown in FIG. 1, there would be eight actuators utilized in two parallel rows. Only three controllers are shown for the sake of convenience, and they will all be connected identically in parallel and constructed identically, and each will operate the servo valves for their respective actuator.

The line 202 thus is connected in parallel with a line 225 to the other controllers 203 for the start and stop signal leading to their respective wave form generators. It should be noted that the wave form generators 204 also receive a signal along the line 226 which provides a master rate signal from one of the draw cycle controllers 230, which is a control signal to control the rate at which the blanking cylinders are operated. The draw cycle controllers are illustrated at 230, and a control signal from the computer for closing the contacts 231 is used to start the draw cycle. The signal from contacts 231 will be provided when the lower limit switch 223 or contacts 223 are closed, which indicates that the blanking die has reached its lower limit and the blank has been cut out by the actuator. The signal to commenee drawing is provided along the line 232 to a wave form generator 233 of the controller 230. The wave form generator 233 provides the master rate signal along the line 226 to each of the wave form generators 204 for the respective controllers 203. This signal may be used to synchronize the control wave form provided by the generator 204 to that of the control signals from the wave form generators 233 to insure that the withdrawal or retraction of the blanking cylinder will be coordinated to the cycle of the draw cylinders.

The controllers 230 are separately provided for each of the individual actuators operating the draw punches. The wave form generators 233 include a master rate trim pot 234 in addition to the up and down rate

trim pots

235 and 236, respectively. Then the rest of the circuit includes a span adjustment 205 and this span adjustment would be connected to a summing junction, gain control, stabilizer valve amplifier and feedback controls as shown in the upper controller 203. The line 237 carries the output control signal for the respective servo valve controlling the draw cylinder. Stroke transducers 91 for the draw cylinders (FIG. 3) or 154 (FIG.

4) provide a feedback signal on the line 238 to the signal conditioner in the controllers as shown in the controllers 203. A switch 240 between each of the wave form generators 233 and its corresponding span control 205 in the controllers 230 permits disabling of one or more of the draw cylinders if desired. It should also be noted that in the controllers 230 for the additional channels other than the first or master channel, there is no need for wave form generators because each of the wave form generators in the draw cycle will be identical, and will be supplied along the line 241 to their respective controllers for the additional channels.

The controllers 230 include limit detectors which comprise contacts indicated at 243, which will provide an upper limit signal of the draw cylinder for the respective actuator which is carried along the line 244 back to the computer. A pair of contacts 245 are used to provide a signal along a line 246 back to the computer showing that the lower limit of the drawing cylinder of the respective actuator has been reached. This lower limit switch contacts are closed prior to the full stroke of the draw cylinder but near the end of the stroke to provide a signal indicating that only a small flange of the blank is left to be formed and that the hold down pad can be released.

The signal from the upper limit detector contacts 243 along line 244 may be used to permit closing of contacts 231 only when the cylinder is back in retracted position, so a cycle will not be initiated until one cycle is completed. The limit detectors provide physical signals necessary for insuring that the cylinders are in their proper position for sequence of opera tion.

It should be noted that the limit detector signals on lines 246 of the draw cylinders are connected by lines 247 to the wave form generators 204 for the respective channels or actuators. The signals may be used to control the blanking command from the wave form generator 204 for that actuator to return the actuator to its raised position. As soon as the lower limit is reached on the draw cylinder, the blanking or cutting cylinder can be retracted.

The hold down pad cylinder for holding the blank during cutting and drawing is controlled by the blanking cylinder. The hold down cylinder advances with the blanking cylinder until the hold down pad contacts the sheet from which the blank is to be cut at which time it is forced against the sheet by a constant force developed by the pressure in accumulator 322A. The blanking cylinder continues to advance until it has cut through the sheet to form the blank for the cup and reaches the end of its stroke. The blanking and hold down cylinders remain in this position in a normal cycle until the lower limit detector of the draw cylinder for that actuator is tripped. The signal from contacts 245 on

lines

246 and 247 is carried to the wave form generator 204 for the corresponding blanking cylinder to retract the blanking cylinder. This also lifts the hold down pad from the blank by overcoming the force of the hold down cylinder and forcing oil back into the associated accumulator 322A.

As mentioned, the limit detector contacts 245 are closed before the full draw stroke is completed so that the last portion of material around the edge of the blank is released by the hold down for the last portion of travel of the draw punch. The release of load from the hold down pad prevents tearing out pieces of metal around the edges of the cup or ironing down the edges to a knife edge.

In FIGS. 8 and 9 graphical representation of the command signals to blanking and drawing servo valves respectively are shown. The representations are plotted as percent of the maximum command signal onthe vertical scale and time on the horizontal scale.

First, referring to FIG. 8, the blanking cylinder wave form is shown. At the start of the cycle indicated at 250, the computer is closing the blanking start/stop contacts 201, and the command signal to the servo valve for the blanking cylinder starts to increase as shown. The blanking cylinders are moved to cut the blanks until the blanking cylinder lower limit is reached and this is indicated at point 251. This means that the blank has been sheared at the time represented as T By referring to FIG. 9, it can be seen that at substantially the same time T which is when the signal has been provided along the lines 224 of FIG. 7 indicating the blanking cylinder lower limit has been reached, the wave form generators 233 for the draw cylinder controllers are actuated by closure of the contacts 231, and a control signal represented by line 252 is providedto the servo valves for the draw cylinders. It should be noted that the blanking cylinders are still held at their lower limit until a time T which is indicated at 253 in FIG. 9, and at 254 in FIG. 8, which is the point of closure of the draw cylinder lower limit detector contacts 245. Then the blanking actuator will be retracted (also retracting the hold down pad) as indicated by signal line portion 255 in FIG. 8. The draw cylinder continues to move down until it reaches the end of its stroke represented at point 256 in FIG. 9, which is indicated as time T The signal for retracting the blanking cylinder reaches zero (fully retracted) at a time T The blanking cylinder portion has then been completely retracted and the blanking upper limit detector contacts 221 are closed and a signal is given along line 222 that the blanking cylinder upper limit has been reached. After this has happened at time T indicated at 257 in FIG. 9, the computer opens the draw contacts 231 for the respective channels and a signal represented by line portion 258 is provided to retract the draw cylinder. This continues until time T when the draw upper limit is reached, and 21 upper limit signal is provided along line 244 by the contacts 243. The shape of the wave form and the time involved can be changed by adjusting the up rate and down rate trip pots of wave form generators 204, and the up and down

trim pots

235 and 236 of the wave form generators 233.

The servo valve controllers and servo valves accurately control the can blanking and forming operations. The servo control loops for the blanking and drawing cylinders are interrelated and timed by limit detectors operated by the stroke feedback signals for accurate operation.

The mounting of the hold down pad as previously mentioned permits tilting of the pad of several degrees. The tilting is sufficient to accommodate a double thick ness of blank (two blanks) at one side of the pad without introducing bending.

What is claimed is:

' 1. In a blanking and forming die press for deep drawn members such as drawn and ironed cans, an actuator with a longitudinal central axis and an outer periphery,

comprising a multi-stage cylinder having a main body, a first cylinder portion movable with respect to said main body adjacent the outer periphery thereof, said first cylinder portion comprising a sleeve mounted over said main body and having piston portions cooperating with portions of said main body to form a fluid cylinder operable to move said sleeve with respect to said main body between a cutting and a retracted position, a hold down member, means defining a hold down cylinder and piston combination acting between said hold down member and said main body, and means to actuate said hold down cylinder to force said hold down member away from said main body, and cooperating means between said sleeve and said hold down member operable to retract said hold down member when said sleeve is retracted, but to permit movement of said sleeve toward its cutting position independently of said hold down member.

2. The combination as specified in claim 1 and limit detector means to determine when said sleeve reaches said cutting position, cooperating stop means between said hold down member and said sleeve to prevent said sleeve from moving to activate said limit detector means if said hold down member is held from moving a desired amount in direction away from said main body.

3. The combination of claim 1 and a cylinder rod having piston portions thereon cooperating with said main body and slidably mounted with respect thereto generally centered along the longitudinal central axis, said center cylinder portions being concentric with said sleeve and said hold down member and operable independently thereto for forming operations.

4. The combination as specified in claim 3 wherein said cooperating means between said sleeve and said hold down member comprise a lug on said hold down member, and a cooperating shoulder on said sleeve operable to retract said hold down cylinder toward said main body when said sleeve is retracted.

5. The combination as specified in claim 3 wherein said actuator includes a longitudinal passageway through said cylinder rod, and a stroke transducer attached between said main body portion and said cylinder rod to provide means for sensing position of said cylinder rod with respect to said main body, said stroke transducer being carried in said passageway.

6. The combination as specified in claim 3 and a longitudinal passageway defined in said cylinder rod, and transfer tube means mounted in said passageway in said rod, the exterior of said transfer tube means being open to a first fluid used for actuating said cylinder rod, sealing means between said rod and the exterior of said transfer tube means, and the interior of said transfer tube means being open to a second fluid supplied to said passageway in said rod.

7. The combination of claim 6 wherein said cylinder rod has two longitudinal passageways spaced from each other, separate transfer tube means in each of said longitudinal passageways, a work element attached to the outer end of said rod, connecting passageways in said work element fluidly connecting said longitudinal passageways, and means to connect the interior passageway of one of said transfer tube means to a source of work element cooling fluid.

8. The combination of claim 1 wherein said main body has a base and an outwardly extending end and first cylinder portion is formed at an outwardly extending end of said actuator and is formed by reducing the cross sectional size of said main body member adjacent the outwardly extending end thereof.

9. The combination of claim 8 wherein said sleeve is positioned to the exterior of said hold down cylinder,

10. The combination of claim 1 wherein said main body has a base end and an outer end and has a reduced cross sectional size portion adjacent its outer end forming a shoulder, a support ring mounted on said reduced cross sectional size portion and having an end surface facing said shoulder and spaced therefrom, said piston portions comprising an internal piston member on said sleeve positioned between said shoulder and said end surface and slidably sealed with respect to the reduced cross sectional portion to form chambers on opposite sides of said internal piston member.

11. The combination of claim 10 and sleeve bearing means for supporting said sleeve, one of said bearing means being mounted on said main body between said shoulder and said base end, and one of said bearing means being mounted in position spaced between the end surface of said ring and the outer end of said actuator.

12. The combination of claim 11 wherein said means defining said hold down cylinder and piston combination are of relative size and said cooperating means include nonsecured engagable members so that said hold down member may tilt between two to five degrees to accommodate irregularities in material contacted by said hold down member.

13. A forming press including a frame having a pair of cross heads fixedly supported relative to each other and spaced apart, a hydraulic actuator comprising a main actuator body having a base end mounted on one cross head and an outer end spaced from the base end and extending toward the other cross head, a blanking and drawing die assembly supported on said other cross head in alignment with said hydraulic actuator, said main actuator body including a cutting cylinder for cutting a blank, and including means defining a hold down cylinder having a hold down member movable to an extended position for engaging and holding a blank cut by said cutting cylinder against said die assembly, and means to directly mechanically support said means defining said hold down cylinder on said main body whereby force developed by said hold down cylinder is reacted directly by said main body to said one cross head and frame, said hold down cylinder being a single acting cylinder and said cutting cylinder being a double acting cylinder, and mechanical means directly acting between said cutting cylinder and said hold down cylinder to move said hold down member away from its extended position as soon as the cutting cylinder retracts past to a position where the mechanical means engage.

14. The combination of claim 13 and a die set including a support pad for supporting a blank, said die set including a blank drawing opening, means to supply pressure to said hold down cylinder to force said hold down member against a blank on said support pad to restrain said blank, punch means to draw a blank being restrained by said hold down member through said opening, and means to control said cutting cylinder to mechanically move said hold down cylinder away from said blank before said blank is completely drawn by said punch means.

15. An actuator used for forming drawn and ironed cans comprising a main cylinder body having a fluid power cylinder cavity defined therein, a piston and 1ongitudinally extending rod assembly mounted in said fluid power cylinder cavity and being actuable by a first fluid under pressure introduced into said fluid power cylinder cavity, said piston and rod assembly having a portion extending to the exterior of said main body, a longitudinally extending passageway in said piston and rod assembly, a transfer tube having a first end portion fixed to said main body and other portions positioned in said fluid power cylinder cavity and having portions slidably mounted in said passageway of said piston and rod assembly, said transfer tube having an exterior surface and an interior passageway, means connecting the interior passageway of said transfer tube to a source of a second fluid to be supplied to the longitudinal passageway of said piston and rod assembly, Sealing means between the exterior of said transfer tube and said piston and rod assembly to slidably seal the longitudinal passageway of said piston from fluid communication with the fluid power cylinder cavity when the piston and rod assembly is actuated.

16. A drawing die press assembly for forming can blanks comprising a frame having first and second cross supports fixed to said frame and spaced apart, a drawing die member mounted on said first cross support and defining an opening, fluid pressure cylinder means mounted on said second cross support and having an actuable punch member mounted thereon and movable to enter the die member opening under fluid pressure to form a can blank supported on the die member directly over the opening, said fluid pressure cylinder means further including a fluid pressure operated hold down member operable to engage a can blank in position resting on said die member and hold said blank under force as the punch member enters the drawing die member opening, said die member and said punch member being positioned so that the surface of a blank supported on said die member when the blank is held by said hold down member lies generally along a common bisecting plane between said cross supports, and said cross supports having substantially the same resistance to bending under loads from said fluid pressure cylinder means so that bending of said cross supports under load results in the center lines of said die member and said mating punch member intersecting at a point lying substantially in said bisecting plane.

17. A cupping press including a frame support, a plurality of actuators for use with a blanking and drawing die for forming drawn and ironed cans supported on said frame, each actuator comprising a main actuator body having a base end and an outer end spaced from the base end, each main actuator body including a cutting cylinder for cutting a blank, and including means defining a hold down cylinder having a hold down member movable to an extended position for engaging and holding a blank cut by said cutting cylinder on said blanking and drawing die, separate hydraulic manifold means for providing hydraulic connections to each of said actuators, and hydraulic connecting means between the manifolds of first and second adjacent actuators comprising a connecting tube having a first end portion slidably sealingly mounted in a first manifold and being inserted into said first manifold a desired amount, a flange at a second end of said tube, and means to sealingly connect the flange to a second manifold without substantial projection of said tube into said second manifold whereby the center-to-center distance between manifolds may be changed without changing connecting tubes, and one of said manifolds may be removed after disconnecting said flange.

Claims

1. In a blanking and forming die press for deep drawn members such as drawn and ironed cans, an actuator with a longitudinal central axis and an outer periphery, comprising a multi-stage cylinder having a main body, a first cylinder portion movable with respect to said main body adjacent the outer periphery thereof, said first cylinder portion comprising a sleeve mounted over said main body and having piston portions cooperating with portions of said main body to form a fluid cylinder operable to move said sleeve with respect to said main body between a cutting and a retracted position, a hold down member, means defining a hold down cylinder and piston combination acting between said hold down member and said main body, and means to actuate said hold down cylinder to force said hold down member away from said main body, and cooperating means between said sleeve and said hold down member operable to retract said hold down member when said sleeve is retracted, but to permit movement of said sleeve toward its cutting position independently of said hold down member.

9. The comBination of claim 8 wherein said sleeve is positioned to the exterior of said hold down cylinder.

15. An actuator used for forming drawn and ironed cans comprising a main cylinder body having a fluid power cylinder cavity defined therein, a piston and longitudinally extending rod assembly mounted in said fluid power cylinder cavity and being actuable by a first fluid under pressure introduced into said fluid power cylinder cavity, said piston and rod assembly having a portion extending to the exterior of said main body, a longitudinally extending passageway in said piston and rod assembly, a transfer tube having a first end portion fixed to said main body and other portions positioned in said fluid power cylinder cavity and having portions slidably mounted in said passageway of said piston and rod assembly, said transfer tube having an exterior surface and an interior passageway, means connecting the interior passageway of said transfer tube tO a source of a second fluid to be supplied to the longitudinal passageway of said piston and rod assembly, sealing means between the exterior of said transfer tube and said piston and rod assembly to slidably seal the longitudinal passageway of said piston from fluid communication with the fluid power cylinder cavity when the piston and rod assembly is actuated.