US2325146A - Drawing press - Google Patents

Description

' pRAwING PRESS FiledA April 29, 1942 JOH BY 'INVENTOR AN A. MULLER me. m

ATTRNEYS ating the press platen.'

A Patented 'July 27, 1943 OFFICE DRAWING PRESS Johan A. Muller. Dayton,

Hydraulic Development mington,

Corporation, Del., a corporation of Delaware Ohio, assigner to The Inc.. Wil- Application April 29, 1942, Serial No. 441,042

14 Claims.

This invention relates to presses and, in particular, to hydraulic presses having blank-hold ing arrangements in association with drawing devices.

A well known type oi' presses of the above character comprises a press platen operated by a ram and provided with clamping cylinders, which have reciprocably mounted therein clamping plungers for actuating a blankholder platen. While this type of presses works very satisfactorily, it has the clamping cylinders arranged separate from the ram, thereby requiring machining of the press ram and the clamping cylinders in different machining setups.

It is, therefore, an object of the invention to provide an improved blankholder press, which will enable machining of the press ram and clamping cylinders iny a single machining setup.

It is another object of the invention to provide a blankholder press, in which the press ram is provided with a recess conning a clamping cylinder for receiving the clamping plunger for actuation of the blankholder platen.

It is another object to provide an improved blankholder press with an increased guiding length for guiding the blankholder means actu- It is still another object of the invention to provide a blankholder press having a clamping cylinder piston arrangement for actuating the blankholder platen, in which the packing heretofore required for preventing undue leakage from the clamping cylinder piston arrangement may be' omitted without allecting the eiliciency ofsaid vclamping cylinder piston arrangement.

A still further object of the invention consists in the provision of a blankholder press in which the clamping plungers for actuating the blankholder platen are guided in the press platen and the press ram for actuating the latter.

These and other objects and advantages of the invention will appear more clearly from the following speciilcation in connection with the accompnying drawing diagrammatically showing a press according to the present invention.

General arrangement and extending into said press plunger means,v

which latter form a clamping cylinder.

The clamping cylinder in the press plunger means communicates with 'auxiliary cylinder means through conduit means supported by said press plunger means and adapted to telescope into said auxiliary cylinder means.

Structural arrangement l Referring now to 'the drawing in detail, the structure shown therein comprises a press head I with two main or press cylinders 2, 3, having respectively mounted therein press rams 4, 5. Each of the press rams 4, 5 is provided with a cavity 6, l, forming a clamping cylinder for co`k operation with clamping spectively.

The clamping plungers plungers 8 and 9 re- 8 and 9 are connected I Il in any convenient manner, for instance by screws II. Each of the clamping plungers 8 and 9 passes through bushings I2, I3 in the press platen I4 and through packing I5, I6 in the rams 4, 45. The press platen I4 is connected to the rams 4, 5 in any convenient manner, for instance by split rings I1 and I8 and screws I9.

The press platen I 4 carries a press plunger or die 20 adapted'to pass through an opening 2| in the blankholder platen I D, which latter has connected thereto suspension rods 22, 23 respectively extending through bores 24, 25 in the press platen I4, and having threaded thereto nuts 26, 21 for abutment with the upper surface of the press platen I4 so as to maintain the clamping platen I0 suspended when the latter is spaced from the work piece to be shaped. Also connected with the press platen I4 is a control arm 28 adapted lto engage a collar 23 adjustably mounted on a push rod 30. 'Ihe push rod 30 also has adjustably mounted thereon a collar 3I for cooperation with an arm 32 of a threearm lever, generally designated 33, which lever is pivotally connected with a link 34 which, in its turn, ispivotally connected to an armature 35 controlled by a solenoid 36. The arm 31 of the three-arm lever 33 is connected through a linkage system 38 with a control rod 33 for controlling the position of the flow-control member pertaining to a reversible variable delivery pump 40 and adapted, in one position, to cause the pump 40 to deliver pressure iluid into the conduit 4I, while movement of the flow-control member into another position causes the pump 40 to deliver pressure iluid into the conduit 42.

ing the latter to actuate the armature .in its turn, shifts the three-arm lever 33 and The conduit 4I leads to the upper portion of the press cylinder 3, which upper portion is in continuous fluid connection with the upper .portion of the press cylinder 2 by meansof a conduit 43, a casing 44 and a conduit 45, branching oil from the conduit 45 and leading to a main cylinder relief and pump by-pass valve 41. Also conected with the valve 41 is a conduit 43 leading into the conduit 49 and a conduit 49 connected with the conduit 50. One end of the conduit 59 leads to a two-way valve 5I, while the other end of the conduit 50 communicates with a conduit 52. The conduit 52 branches off from the conduit 42 and leads to a surge valve 53. The surge valve 53 may be of any standard design, for instance of the type set forth in U. S. Patent No. 2,193,248 to Ernst, and servesV to preilll the press cylinders 2 and 3 during the rst portion of the downward strokes of the rams 4 and 5, during which the rams move downwardly by gravity.

The main cylinder relief and pump by-pass valve 41 serves to initiate the retraction strokes of the press rams, and for a more detailed description of the said valve 41, reference may be had to U. S. Patent No. 2,268,205 to Ernst.

The conduit 42 leads to the lower portion of the press cylinder 3, which portion is connected by means of a conduit 54 with the lower portion of the press cylinder 2. The conduit 54 communicates with a conduit 55 comprising a check valve 56 located in a iiuid reservoir or tank 51 which houses the valves 41, 5I and 53. Also' connected with the uid tank 51 are conduits 58 and 59 respectively comprising pressure relief valves 99 and 8|, and leading to auxiliary cylinders 92 and 63 connected in any convenient manner with the press head I.

The cylinder 52 communicates with a conduit 54 comprising a check valve 85 and communicating with a conduit 95. The conduit 55 comprises check valves 61 and 93 and leads to a conduit 69, which latter is connected with the cylinder 53 and comprises a check valve 10. The conduit 56 is also connected with the two-way valve 5I by means of a conduit 1 I. The valve 5I is normally held by means of a spring, not shown, in such a position as to prevent fluid connection between the conduit 1I and the exhaust conduit 19. However, in response to a predetermined pressure in the conduit 50, the valve 5I overcomes the thrust of the said spring, thereby establishing fluid connection between the conduits 1I and 16.

Reciprocably mounted in each of the cylinders 52 and 93 are hollow auxiliary plungers 12' and 13 respectively, which latter are connected to the rams 5 and 4, and establish fluid connecv tion between the interior of the cylinders 32 and 93 and the cavities 9 and 1 in the rams 5 and 4.

The plungers 12 and 13 pass through bushings 14 and 15 respectively, partly located in the auxiliary cylinders and partly located in the press cylinders.

Operation It maybe assumed that all parts of the press occupy the position shown in the drawing, and that it is now desired to cause the press to perform a working cycle. To this end, the oper- -ator starts the pump 40 in any convenient manner, and energizes the solenoid 35, thereby caus- 35 which,

the linkage system 39 so as to cause leftward movement of the control rod 39.

As a result thereof, the pump is moved into full delivery forward stroke position so as to deliver pressure fluid through the conduit 4I into vthe upper portion of the press cylinder 3. From here a part of the fluid ows through the conduit 43, casing 44 and conduit 45 into the upper portion of the press cylinder 2, while simultaneously uid is withdrawn from the lower portion of the press cylinders 2 and 3 through the conduit-s 54 and 42. Therefore, the rams 4 and 5 move downwardly as fast as uid is withdrawn from the lower portion of the press cylinders 2 and 3. The fluid delivered into the upper portion of the press cylinders 2 and 3 is, at this time, supplemented by fluid passing from Vthe tank 51 through the surge valve 53 and conduits 43 and 55 into the cylinders 3 and 2.

Downward movement of the'rams 4 and 5 also causes the press platen I4, connected to said rams, to move downwardly, and inasmuch as the blankholder platen I0 is suspended on the press platen I4, also the blankholder platen I0 and the clamping plungers 9 and 9, connected thereto, move downwardly.

The vacuum created in the auxiliary cylinders 62 and 63 by downward movement of the auxiliary plungers 12 and 13 connected to the ,rams 4 and 5 respectively, is lled byuid passing from the tank through the check valves 65 and 10.

As soon as the blankholder platen I0 engages the work piece to be shaped, the blankholder platen comes to a halt, thereby also halting the clamping plungers 8 and 9. While the rams 4 and 5 are continuing their downward movement,

cylinders 1 and 6 respectively and, since the space occupied by said clamping plungers 8 and 9 is larger than thev space released by the hollow plungers 12 and 13 in the cylinders 62 and 63, pressure begins to build up in the clamping cylinders 6 and 1 so as to cause the blankholder platen I0 to hold the work piece clamped at a certain pressure. Simultaneously the pressure in the clamping cylinders 6 and 1 causes the check valves 65 and 10 to close.

It will be noted that, since the valve 5I at this time prevents fluid connection between the conduits 1I and 16, no fluid can escape from the conduits 64 and 69 into the tank 51.

When the above mentioned pressure exceeds a predetermined value, corresponding to the setting of the pressure relief valves 60 and 6I, the excessive Apressure is released through said relief valves. The'press platen I4 and press plunger 20 now continue their downward movement, thereby drawing or shaping the work piece, held by the blankholder platen I0.

When the press plunger 20 has completed its drawing or shaping operation, the operator deenergizes the solenoid 36, thereby allowing a spring, not shown, in the pump 40 to shift the flow-control rod 39 toward the right so as to move the pump 40 into full delivery retraction stroke position. Pressure fluid is now delivered by the pump 40 into the conduit 42, from where it flows through the conduit 52 to the main cylinder relief and pump by-pass valve 41 to actuate the same so as to release fluid from the upper portion of the press cylinders 2 and 3.

Furthermore, fluid from the conduit 52^is conveyed to thesurge valve 53 to4 open the latter surge valve between the upper portion of the assaut press cylinders and the tank 61. Fluid also ows from the conduit 62 to the two-way valve 6I and shifts the same so as to eilect iluid connection between the conduits 1I and 16. l

Fluid pressure delivered bythe pump 46 into theconduit 42 is now conveyed to the lower portion of the press cylinders 3 and 2 where-it causes upward movement of the press rams and, thereby, of the press platen I4 and the press plunger 20. 'I'he uid expelled from the upper portion of the press cylinders during the upward movement of the press rams passes through conduits 43 and 45 and the surge valve 63 in to the tank 51. Y While the rams 4 and 5 move upwardly, ythe press platen I4 moves away from the blankholder platen hollow plungers 1,2 and 13 when moving into their respective cylinders 62 and 63. I! the fiuid expelled by the plungers 12 and 13 is not suilicient to fill the increased space in the cylinders 6 and .1,

I so that the free space in the' clamping cylinders 6 and 1 increases. 'I'his space issubstantially lled with uid expelled by the 3 to the present invention consists in that 6 and l throughout the width oi' the press platen, and that the clamping plungers 6 and 3 and .6. In this way. the clamping plungers 6 and 6 have a relatively large portion continuouslyA guided, so that with smaller presses no particular guiding Agibs for the The press platen, in this instance. is rigidly cona nected with the clamping plungers 6 and 3.

Since the clamping cylinders 6 and 1, according to the arrangement provided in the rams 6 and 4. the bore through which the clamping plungers 6 and 3 extend into the cavities 1 and 6 maybe machined in the same machining setup for machining the exterior" surface of the rams. I'he cavities 6 and 1 are cast and need no machining. In this way. the costs of manufacturing the press according to the invention are materially decreased over the costs-involved in machining cylinder presses as heretofore known.

The provision of the cavities s and 1 in the rams 4 and 6 constitutes an important saving in "thematerial for the rams.

whue the structure shown in the erewmg merelyv shows two press rams with two clamping cylinders therein, it is, of course,.understood that the arrangement may be multiplied. If desired,

- the press may be provided with some rams havand 1| through the two-way valve 5i and exhaust conduit 16 into the tank 51.

When the press platen Ill of its retraction stroke, the collar 29 is engaged by the platen arm 28 so that the push rod 30 is lifted and causes the collar 3i to shift the threearm lever 33 in anti-clockwise direction to such an extent that the control rod 39 moves the pump 40 into substantially neutral or no delivery position. Consequently, no more pressure fluid is delivered to the lower portion of the press cylinders 2 and 3 so that the press rams 4 and 5 come to a halt. All parts now occupy the position shown in the drawing and the press is ready for a new cycle.

From the above it will be seen that the cavities 6 and 1 act as clamping cylinders for cooperation with the clamping plungers 9 and 6 to exert the desired clamping pressure on the blankholder platen I0. It will .furthermore be noted that, since iluid pressure is conveyed through the hollow plungers 12 and 13 into the auxiliary cylinders 62 and 63 from the cavities 6 and 1, the pressure in the avities 6 and 1 also acts upon the marginal `or annular areas of the hollow plungers 12 and 13, thereby also acting on the rams 5 and 4 connected to the plungers 12 and 13. In other words, not the total pressure acting on the upper surface of the clamping plungers 8 and 9 is to be derived from the pressure acting on the rams 4 and 5, but only the pressure acting on a clamping plunger area, which equals the sectional area of the bores 11 and 18 in the hollow plungers 12 and 13.

It should also be noted that, since during the pressing operation pressure prevails in the cylinders 62 and 63 as well as in the upper portion of the press cylinders 3 and 2, it is quite suf- Il cient to provide bushings 14 and 15 through and 13 pass and no packing approaches the end ing clamping cylinders therein, 'and other rams having no clamping cylinders associated therei with.

It win be understood that I desire to comprehend within my invention such modifications as come within the scope of the claims and the invention.

Having thus fully described myinvention, what I claim as new vand desire to secure by Letters Patent, is:

l. In combination in a drawing press, a reciprocable press platen, fluid operable plunger means for actuating said platen, said plunger j means having a cavity therein conning a clamping cylinder, blankholder means for holding a being shapedpby pressure exerted 0n said press plunger means .reciprocable in said clamping cylinder for actuating said blankholder means, said clamping plunger means being arranged to create pressure in said clamping cylinder in response to the movement of said press platen toward said blankholder means.

2. In combination in a drawing press, a hollow press ram conilning a clamping cylinder, iluid operable advancing and retracting means associated Vwith said ram for reciprocating the same, blankholder means for holding a workpiece while it is being shaped by pressure-exerted .on said press ram, and iluid operable clamping plunger means reciprocable in saidclamping cylinder and operatively connected with said blankholder means for conveying pressure thereto.

3. In combination in a drawing press, a press ram having a cavity therein forming a clamping cylinder, motor means for reciprocating said ram,

ram, and iluidoperable clamping plunger means reciprocable in said clamping cylinder and responsive to a relative movement between said ram and said blankholder means for pressure in said clamping cylinder and said pressure to said creating conveying blankholder means. f

me bushings I2 and I3 guide the clamping "plungersare rurthermore guided bythe lower end o! the rams 4 of the present'invention, are' platen, and clampingvv 4. In combination in a drawing press, a hollow press ram comming a main clamping cylinder, fluid operable advancing and retracting means for reciprocating said ram, blankholder means for holding a work piece while it is being shaped by pressure exerted on said ram, main clamping plunger means reciprocable in said main clamping cylinder and operatively connected with said blankholder means for conveying pressure thereto, an auxiliary clamping cylinder, and a hollow auxiliary clamping plunger hydraulically interconnecting said main and said auxiliary clamping cylinders, said main clamping plunger means being adapted in response to a relative movement between said ram and said blankholder means to create pressure in said'clamping cylinders.

5. In combination in a drawing press, a press platen, a plurality of press rams connected to said platen for actuating the same, each of said rams being hollow and confining a clamping cylinder, fluid operable advancing and retracting means for reciprocating said rams, blankholder means for holding a work piece while it is being shaped by pressure exerted on said platen, and a plurality of clamping plungers arranged to-move with said blankholder means and respectively reciprocable in said clamping cylinders for creating pressure therein in response to a relative movement between said press platen and said blankholder means, and for conveying said pressure to said blankholder means.

6. In combination in a drawing press, a press platen, hollow ram means confining clamping cylinder means, blankholder means for holding a work piece while it is being shaped by pressure exerted on said ram means, clamping plunger means arranged to move with said blankholder means and reciprocable in said clamping cylinder means, and means for moving said ram means relative to said blankholder means for creating pressure in said clamping cylinder means and conveying said pressure to said blankholder means.

7. In combination in a drawing press, a press platen, fluid operable hollow ram means confining clamping cylinder means and connected to said platen for reciprocating the same, blankholder means for holding a work piece while it is being shaped by pressure exerted cn said platen, fluid operable clamping plunger means reciprocable in said clamping cylinder means and guided by said platen for blankholder means, said clamping plunger means being adapted in response to a relative movement between said platen and said blankholder means to create pressure in said clamping cylinder means, and means for conveying fluid into said clamping cylinder means.

8.' In combination in a drawing press, fluid operable hollow drawing plunger means, a press platen operable by said plunger means, blankholder means for holding a work piece While it is being shaped by pressure exerted on said drawing plunger means, and clamping plunger means reciprocable in said drawing plunger means, said clamping plunger means being connected to said blankholder means and operable by the motion of said press platen.

9. In combination in a drawing press, drawing cylinder'means, drawing plunger means therein, a press platen operated by said drawing plunger means, clamping cylinder-piston-assernblies associated with said platen and operable automatically to create pressure therein in response to the movement yof said .drawing plunger means in conveying pressure to said drawing direction, the cylinders of said clamping cylinder-piston-assemblies being formed by said drawing plunger means. a clamping platen operable by said clamping cylinder-piston-assemblies for holding a work piece clamped while it is subjected to shaping pressure by said drawing plunger means through said press platen, auxiliary cylinders, auxiliary plungers movable in said auxiliary cylinders, means for conducting fluid between said clamping cylinder-piston-assemblies and said auxiliary cylinders, and a pressure relief device for each auxiliary cylinder adapted to discharge fluid therefrom in response to the attainment of a predetermined pressure therein.

10. In combination in a drawing press, a press head having a drawing cylinder, a hollow drawing plunger therein confining a clamping cylinder, a platen operated by said drawing plunger, blankholder means for holding a work piece while it is being shaped by pressure'exerted on said drawing plunger, a clamping plunger reciprocable. in said clamping cylinder and connected to said blankholder means for conveying pressure thereto, an auxiliary cylinder mounted on said press head, an auxiliary plunger movable in said auxiliary cylinder and connected to said drawing plunger, means for conducting fluid between said clamping cylinder and said auxiliary cylinder, and a pressure relief device associated with said auxiliary cylinder and adapted to discharge fluid therefrom in response to the attainment 'of a predetermined pressure thereon, the working surface of the head of said auxiliary plunger and said drawing plunger being positioned in similar direction relative to said platen, whereby the pressure fluid generated in said clamping cylinder during the clamping operation acts against the auxiliary plunger in the same direction as the pressure exerted on said platen by said drawirg plunger during the pressing operation thereo 1l. In combination in a drawing press, a drawing cylinder, a hollow drawing plunger therein confining a clamping cylinder, a press platen operated by said drawing plunger, blankholder means for holding a work piece while it is being shaped by pressure exerted on said platen, a clamping plunger reciprocable in said clamping cylinder and operable by movement of said platen relative to said blankholder means for exerting pressure on the latter, an auxiliary cylinder, an auxiliary hollow plunger connectedv to said clamping cylinder and reciprocable in said auxiliary cylinder, and a pressure relief device associated with said auxiliary cylinder and adapted to discharge fluid therefrom in response to the attainment of a predetermined pressure therein.

l2. In combination in a drawing press, a drawing cylinder, a hollow drawing plunger therein confining a clamping cylinder, a press platen operated by said drawing plunger, blankholder means for holding a work piece While it is being shaped by pressure exerted on said platen, a clamping plunger reciprocable in said clamping cylinder and operable by movement of said platen relative to said blankholder means for exerting pressure on the latter, an auxiliary cylinder, an auxiliary hollow plunger connected to said clamping cylinder and reciprocable in said auxiliary cylinder, a pressure relief device associated with said auxiliary cylinder and adapted to discharge fluid therefrom in response to the attainment of a predetermined pressure therein, a fluid reservoir, and valve means arranged automatically to prevent fluid connection between said clamping cylinder and said iiuid reservoir during the pressingoperation of said drawing plunger and adapted in response to the retraction stroke of said drawing plunger to establish fluid connection between said clamping cylinder and said uid reservoir.

13. In combination in a drawing press, a draws ing cylinder, a hollow drawing plunger reciprocable in said drawing cylinder and confining a clamping cylinder, blankholder means for holding a work piece while shaping pressure is exerted' 14. In combination in a drawing press, a press platen, a drawing cylinder, a. hollow drawing 4plunger reciprocable in said cylinderA for actuating said press platen, said drawing plunger conilning a clamping Vcylinder,-blankholder means for holding a work piece while ii; is being shaped l by pressure exerted on said press platen, a fluid operable clamping plunger reciprocable in said clamping cylinder for conveying pressure to said blankholder means, said clamping plunger extending through said press platen and being movable relative thereto, means in said press platen for'guiding said clamping plunger, an auxiliary cylinder, means for admitting uid to said auxiliary cylinder, and a hollow auxiliary plunger supported by said drawing plunger and reciprocable in said auxiliary cylinder for continuously establishing hydraulic connection between said clamping cylinder and saidv auxiliary cylinder, said clamping plunger cooperating with said clamping cylinder for creating pressure therein in response to the movement of said press platen toward said blankholder means. y

i JOHAN A. MULLER.

Images