US2693780A - Pressure controlled forming apparatus - Google Patents

Description

1954 M. A. WINTER PRESSURE CONTROLLED FORMING APPARATUS 2 Sheets-Sheet 1 Filed Feb. 10, 1951 INVENTOR BY M 2 1954 M. A. WINTER PRESSURE CONTROLLED FORMING APPARATUS 2 Sheets-Sheet 2 Filed Feb. 10, 1951 INVENTOR 072%72-73 ATTORNEY Unie States Patent PRESSURE CONTROLLED FORMING APPARATUS Mahlon- A. Winter, Baltimore, Md, assignor to The Glenn L. Martin Company, Middle River, Md., 2 corporation of Maryland Application February 10, 1951, Serial No. 210,354

Claims. (Cl. 113-44) This invention relates to an improved apparatusv for controlled pressure forming of metal blanks about a die block, of the type wherein a resilient pad or block of rubber or rubber-like material, maintained under controlled pressure, serves as the forming medium. Apparatus of this same general type has been fully shown and described in co-pending applications, Serial No. 30,766, Serial No. 65,552, now Patent No. 2,605,731, issued August 5, 1952, and Serial No. 170,106 to which reference is hereby made.

Apparatus of this type is desirably made as a separate unit which is adapted to be inserted between the movable and stationary platens of a conventional hydraulic press. Incorporated in such apparatus is a. vertically movable pressure plate or template which is adapted to apply the desired variable pressure to the rubber pad in the head. This pressure plate is supported by fluid pressure means and must be movable against the fluid pressure therein from an uppermost position, substantially level with the top of the die block, to an extent equal to the maximum desired depth of forming. At the same time it must be. so supported as to withstand substantially the entire force developed by the press, which in practice may run up to several hundreds or even thousands of tonsv and to distribute it to the fluid pressure unit and thence to the stationary platen of the press. Likewise the die block itself must be rigidly supported from the stationary platen of the press so as to withstand a relatively large percentage of' the total force available in the press. However the clear space (commonly referred to as the daylight opening) between the upper and lower platens of such presses is usually quite limited and to permit the use of a controlled-pressure forming unit therein, the latter must be relatively small and compact and of but limited vertical extent. These conflicting requirements pose a serious problem in the design of such apparatus.

An object of this invention is to provide such a forming. unit of relatively simple construction but which at the. same time provides the desired strength and compactness, and which is therefore readily useable in a press having but a relatively small daylight opening.

A further object is to provide such a unit wherein a pair of. spaced fluid pressure units conjointly support a relatively massive superstructure partially enclosing said units.

and having a channel formed transversely across the. upper surface thereof, the pressure plate being supported directly from the superstructure in bridging relation to said' channel.

A further object is to provide a generally U-shaped support for the die block, said support straddling the superstructure with its cross member traversing the channel therein and adapted to support the die block medially thereof.

Further objects and advantages will become apparent from the following description and claims especially when considered in conjunction with the drawing wherein:

Figure 1 is a fragmentary front view of the forming apparatus.

Figure 2 is an end view thereof, and

Figure 3 is a top plan view.

The forming apparatus of this invention is primarily intended for use in conjunction with a forming press of the type havinga movable head 1 having a cavity 2 formed.

therein and opening downwardly as at 3, said cavity being substantially filled with a resilient pad 4 of rubber or. rubber-like. material. In. such a forming apparatus the pad 4, upon downward. movement. of the head. toward the, sta- Patented Nov. 9, 1954 tionary platen of the press, serves as the forming. medium. for forming a blank about a die block 6 carried on the stationary platen 5.. As was shown and described in the. above mentioned co-pending applications, a pressure plate 7 surrounds the. die block 6 and is mounted for vertical movement. relative thereto, such movement being resisted in a predetermined fashion so as to control the pressure within the rubber pad 4 throughout the forming operation.

In the instant case, the pressure plate. is supported by a pair of spaced fluid pressure units 8, each including a. piston 9 rigidly supported from the stationary platen 5, and a cylinder 10 telescopically associated therewith. The hydraulic units 8 conjointly support a massive superstructure 11, provided with a pair of recesses 12 adapted to receive. and house the hydraulic units therein as clearly trapped therein.

shown in Figure l. The upper surface of the superstructure 11 is formed to provide a channel 13 extendingtransversely thereacross. A sealing ring 14 is supported on the upper edges 15 of the channel walls, the shape and dimensions of the sealing ring being such as to mate the opening 3 in the head. Pressure plate 7 rests directly upon ring 14, the ring and plate bridging the channel as clearly shown in the drawing. Posts 16 are also provided to furnish. additional support for the intermediate portions of thel plate 7 directly from the bottom wall 17 of the channe Tosupport the die block 6 an inverted generally U- shaped support 18 is provided, said support straddling. the superstructure and: comprising a pair of spaced legs 19- and. a bolster 20 rigidly carried thereby and constituting. the cross-member of the U-shaped support. As clearly shown in the drawing, bolster 20 traverses the channel 13 and supports the die block 6 medially thereof. Suitable holes 21 are provided through the bolster 20 for receiving the pressure plate supporting posts 16. Since the. forces involved are extremely great during the forming operation, additional support for the intermediate portion of the bolster is provided by a pair of generally rectangular posts 22 resting on the stationary platen. 5' and extending through openings 23 provided in the median rib- 24 of the superstructure. As shown in Figure 2, these posts. directly contact the undersurface of the bolster 20. Additional support may also be provided by means of a plurality of posts such as at 25, said last. mentioned posts also extending from the stationary platen into direct supporting relationship with the underside of the bolster.

Housed with the front leg 19 of the U-shaped support control plunger 27 thereof carrying at its outer end a cam follower roller. 28

tails: of this control valve form no part of the present invention, but if further details are desired, reference. may be had to application Serial No. 65,552 wherein such a valve is fully described and illustrated. Suitable control surfaces 30 and pressure gauges 31 may also be conveniently grouped on the upwardly inclined surface. of the front leg 19 as indicated in the drawing. Housed within the. rear leg: 19 of the U'-shaped support is a sole.- noid actuated stripper control valve, the purpose of which will become apparent herebelow.

Only so much of the fluid pressure control system is shown diagrammatically in the drawing as is deemed necessary to an understanding of the operation of the device. At the beginning, of a forming operation, cylinders 10 will be full of hydraulic fluid and will support the super-- structure 11 and pressure plate 7 in the relationship shown in Figures 1 and 2 with the blank to be formed (not shown) resting on the latter. During the forming; operation, as the head 1 is lowered, the rubber pad Wilkbfl confined therein by the pressure plate and sealing ring and the. pressure transmitted thereby to the pressure plate 7 will, in turn, be applied through the superstructure 11 to the. cylinders 10 to build up pressure within the fluid When this fluid pressure reaches a value corresponding to the instantaneous pressure set-- ting of the. control valve 26, fluid will be permitted to flow from. the. cylinders through conduits 33 and will be conducted as by conduit 34 to and through the pressure adapted to ride along a control cam 29. rigidly supported on the. superstructure. The specific de-v control valve 26 and thence, as at 35, to an accumulator 36. As the fluid flows out of the cylinders, the superstructure with its pressure plate 7 will be permitted to move downwardly a corresponding amount, the rubber pad serving to thereupon form the blank about the die block. Since the pressure setting of the valve 26 is controlled by the cam 29, which in turn is mounted upon and movable with the superstructure 11, it can readily be seen that the pressure acting between pressure plate 7 and the rubber pad 4 will at all times be controlled in predetermined relationship to the relative position of the pressure plate and the die block. Since the rubber pad is completely confined during the forming operation, the pressure transmitted thereto by the pressure plate 7 will be distributed in all directions throughout the pad. Thus the pressure in the rubber pad is at all times positively controlled in accordance with the progress of the forming operation.

At the completion of the forming operation, the head will be raised as in normal operation, and, when it has been raised to a predetermined point, a suitable switch (not shown) will be actuated to energize the solenoid of the stripper valve 32 so as to open this valve. Fluid will then flow as diagrammatically indicated at 37 and 38, from the accumulator, through the stripper valve and into the cylinders 10 by way of the conduit 33 to restore the parts to their original position. Reference is made to co-pending applications Serial No. 65,552 and Serial No. 170,106 for more detailed information as to suitable hydraulic and electrical control systems for use with such forming apparatus.

By constructing the parts as shown, an extremely effective mechanism results. By supporting the die block from a U-shaped member straddling the superstructure and lying within the channel .13 thereof, the overall height of the device is kept to a minimum while at the same time providing the necessary support and distribution of the forces involved. This feature is particularly important, where the daylight opening between the head and stationary platen of the press is relatively small and a forming apparatus of comparatively great height cannot be tolerated.

While in the embodiment ring has been shown for illustrated, a separate sealing insuring a close fit with the opening in the head, this element could obviously be omitted and the pressure plate itself shaped to closely mate the opening. However by providing the separate sealing ring, it is possible to use a pressure plate which has been cut but roughly to size, thereby reducing the tooling costs for a particular forming job.

Other changes and modifications can obviously be made without departing from the spirit and scope of the invention as defined by the appended claims.

I claim as my invention:

1. In a forming apparatus of the type having a head movable toward a die block for forming a blank thereabout and wherein said head is provided with a downwardly opening cavity and a pad of resilient material substantially filling said cavity and constituting the forming medium, apparatus for supporting said die block and for placing said pad under controlled pressure throughout the forming operation, comprising a pair of spaced expansible fluid pressure resistance units, each including a fixedportion and a relatively movable portion conjointly arranged to contain pressure fluid therein, and means for supplying pressure fluid to said units, downward movement of said moveable portions being resisted in accordance with the fluid pressure in said units at any time, a superstructure spanning said units and conjointly supported by the movable portions thereof, said superstructure being formed to provide an upwardly opening channel extending transversely across the upper face thereof beneath said pad, a generally U-shaped die block support straddling said superstructure with its cross member extending through said channel and supporting said die block therein, means comprising a pressure plate carried by said superstructure in bridging relationship to said channel and cooperating with said head to completely confine said pad therein throughout the forming operation, said pressure plate having an opening therein adapted to slidably receive said die block, and means responsive to relative movement between said pressure plate and said die block for variably controlling the fluid pressure within said units in predetermined relationship thereto.

2. In a forming apparatus of the type having a head movable toward a die block for forming a blank thereabout and wherein said head wardly opening cavity and a pad of resilient material substantially filling said cavity and constituting the forming medium, apparatus for supporting said die block and for placing said pad under controlled pressure throughout the forming operation, comprising a pair of spaced expansible fluid pressure resistance units, each including a fixed portion and a relatively movable portion conjointly arranged to contain pressure fluid therein, and means for supplying pressure fluid to said units, downward movement of said moveable portions being resisted in accordance with the fluid pressure in said units at any time, a superstructure spanning said units and conjointly supported by the movable portions thereof, said superstructure having its under portion recessed to receive and partially house said units therein with the sides of said superstructure extending downwardly alongside said moveable members throughout the major portion of their height and said superstructure having an upwardly opening channel extending transversely across the upper face thereof beneath said pad, a generally U-shaped die block support straddling said superstructure with its cross member extending through said channel and supporting said die block therein, means-comprising a pressure plate carried by said superstructure in bridging relationship to said channel and cooperating with said head to completely confine said pad therein through the forming operation, said pressure plate having an opening therein adapted to slidably receive said die block, and means responsive to relative movement between said pressure plate and said die block for variably controlling the fluid pressure within said units in predetermined relationship thereto.

3. Forming apparatus for use in conjunction with a press having a base and a vertically movable head employing a resilient pad in said head as the forming medium, said apparatus comprising a pair of laterally spaced fluid presusre resistance units each including a piston fixedly carried by the base and a cylinder vertically movable relative thereto conjointly arranged to contain pressure fluid therein, and means for supplying pressure fluid to the interior of said units, a superstructure conjointly carried by and spanning said cylinders, said superstructure having a pair of recesses formed in the under portion thereof adapted to substantially house said cylinders, and the upper surface of said superstructure having a channel formed therein extending transversely thereacross substantially mid-way between the axes of said cylinders, a generally U-shaped die block support carried by said base and straddling said superstructure with its cross member extending through said channel, a die block carried by said cross member within said channel and means comprising a pressure plate carried by said superstructure in bridging relationship to said channel and said cross member and adapted to cooperate with said head to completely confine said resilient pad therein and to apply pressure thereto throughout the forming operation, and means for variably controlling the fluid pressure in said units in predetermined relationship to the relative position of said die block and said pressure plate.

4. Forming apparatus for use in conjunction with a press having a base and a vertically movable head employing a resilient pad in said headas the forming medium, said apparatus comprising a pair of laterally spaced fluid pressure resistance units each including a piston fixedly carried by the base and a cylinder vertically movable relative thereto conjointly arranged to contain pressure fluid therein, and means for supplying pressure fluid to the interior of said units, a superstructure conjointly carried by and spanning said cylinders, said superstructure having a pair of recesses formed in the under portion thereof adapted to substantially house said cylinders, and a medial web separating said recesses and the upper surface of said superstructure having a channel formed therein extending transversely thereacross substantially mid-way between the axes of said cylinders, a generally U-shaped die block support carried by said base and straddling said superstructure with its cross member extending through said channel, said superstructure having a vertical passage-Way formed therein traversing said web and opening through the bottom surface of said channel and auxiliary supporting means extending from is provided with a downsaid base through said passageway into supporting re lationship with the under side of said cross member, a die block carried by said cross member within said channel and means comprising a pressure plate carried by said superstructure in bridging relationship to said channel and said cross member and adapted to cooperate with said head to completely confine said resilient pad therein and to apply pressure thereto throughout the forming operation, and means for variably controlling the fluid pressure in said units in predetermined relationship to the relative position of said die block and said pressure plate.

5. Forming apparatus for use in conjunction with a press having a base and a vertically movable head employing a resilient pad in said head as the forming medium, said apparatus comprising a pair of laterally spaced fluid pressure resistance units each including a piston fixedly carried by the base and a cylinder vertically movable relative thereto conjointly arranged to contain pressure fluid therein, and means for supplying pressure fluid to the interior of said units, a superstructure conjointly carried by and spanning said cylinders, said superstructure having a pair of recesses formed in the under portion thereof adapted to substantially house said cylinders, and the upper surface of said superstructure having a channel formed therein extending transversely thereacross substantially mid-way between the axes of said cylinder, a generally U-shaped die block support carried by said base and straddling said superstructure with its cross member extending through said channel, a die block carried by said cross member within said channel and means comprising a pressure plate carried by said superstructure in bridging relationship to said channel and said cross member and adapted to cooperate with said head to completely confine said resilient pad therein and to apply pressure thereto throughout the forming opera tion, said cross member being provided with a plurality of spaced holes extending vertically therethrough, and a plurality of posts supported from the bottom wall of said channel and extending through said holes into supporting relation with said pressure plate intermediate the Walls of said channel, and means for variably controlling the fluid pressure in said units in predetermined relationship to the relative position of said die block and said pressure plate.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,866,595 Glasner et a1. July 12, 1932 1,919,771 Byerlein July 25, 1933 2,331,430 Shoemaker Oct. 12, 1943 2,485,354 Brannon Oct. 18, 1949

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