US2360007A - Drawing press - Google Patents

Description

Oct. 10, 1944. J. A. MULLER ,3

DRAWING PRESS Figted Dec. 22, 1941 3 Sheets-Sheet 1 Jmm J'OHAN A. MULLER.

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Oct. 10, 1944.

J. A. MULLER DRAWING PRESS Filed Dec 22, 1941 3 Sheets-Sheet 3 Jmveqm JOHAN A. MULLER,

Patented Oct. 10, 1944 DRAWING PRESS I Johan A; Muller, Dayton, Ohio, assignor to The 1 Hydraulic Development Corporation, Inc., Wilmington, Del., a corporation of Delaware Application December 22, 1941, Serial No. 424,000

8 Claims.

This invention relates to drawing presses and,

in particular, to drawing presses comprising feeding means.

One object of this invention consists in the provision of a drawing press having a horizontally moving drawing plunger and an automatically operated feeding system for feeding the work piece to the drawing plunger.

It is another object of this invention to provide a drawing press having a feeding device for feeding the work piece, which is operated in timed relationship with the operation of the drawing plunger.

It is another object to provide a drawing press having an electrical circuit for controlling the forward and return movements of the drawing plunger, which circuit comprises controlling means for controlling a feeding device so as to actuate the latter in synchronism with the drawing plunger.

Still another object of the invention consists in the provision of a drawing press having a blankholding plunger and a drawing plunger, and also comprises a workpiece feeding member which is automatically mov'e'dtoward vand away from the working position, while means is provided to delay the retraction of the feeding member until after the work piece has been engaged by the blank-holding plunger or by the drawing plunger.

This application is a continuation in part of my Figure 7 shows a and 2.

modification of Figures 1 General arrangement In general, the drawing press of this invention is an automatically operative press having a horideep cylindrical seamless metal articles with a closed end, such as, for example, a cartridge case,

or a hand fire extinguisher casing, it has been the practice to form a preliminary cup-shaped article from a flat blank of metal. Several successive operations have then been performed on this cup-shaped piece, each operation increasing the depth and decreasing the diameter thereof until the desired shape is obtained. To produce the preliminary work piece of shallow cup-shaped form from a fiat blank, it has been found concopending application, Serial No.- 275,707, filed May 25,1939.

Theabove and other objects of this invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

Figure 1 diagrammatically illustrates a drawing press according to the inventionin the position it occupies at the end of a working cycle.

Figure 2.is a view similar to Figure 1 but showing the elements of the press in the'position they occupy when approaching the end of a drawing stroke.

Figure 3 is an electric system in'connection with the press of Figures 1 and 2.

Figure 41s an enlarged sectional view through i the'work holder feeding mechanism, showing'the feedin g 'member in its retracted position.

Figures is an enlarged sectional view through the'workpice feeding mechanism taken along theline' 5 -5'of Figure 4.

Figure' di's a' fragmentary view of a portion of Figure 4, showing the feeding member in advanced position.

venient to employ a vertical downwardly-acting press. Where the shape of the work piece is such rather difficult to handle in a-vertical position, I

particularly where it is desired to feed the work piece automatically to the drawing plunger.

It is for this reason that the drawing press of the present invention is constructed and arranged with the main platen and the blank holder platen movable in a horizontal direction and synchronized with a hydraulically actuated feeding device for feeding the elongated work piece to the drawing plunger for the subsequent drawing operations- Structural arrangement Referring to the drawings in detail, the horizontal drawing press of this invention comprises therein a piston II with a piston rod I2, which latter has connected thereto a main platen ii.

The main platen I3 is slidably guided along guiding means of any standard design, not shown in the drawings. Also slidably guided along the said guiding means is a blank holder platen M which is operatively connected to the main platen l3 and movable relative thereto by means of blank holder plungers l5, which reciprocate in blank holder cylinders l6 provided in the main platen l3 iressure fluid for actuating the press plunger H in its working and retraction strokes is provided by means of a pump H, the pressur side of which is connected through conduit l3 with a four-way valve 9, while the suction side of the pump I1 is connected by means of a conduit 26 with a conduit 2| leading to a fluid reservoir or surge tank 22.

Also connected with the four-way valve l9 ill a conduit 23 leading to the right end of the main cylinder I6. -Connected with the opposite end of the main cylinder i6 is a conduit 24 which leads to the four-wayvalve l9.

A fourth conduit, namely conduit 26, connected to the'four-way valve l9, leads to the tank :2.

The four-way valve i9 has a valve member 26, which is continuously urged, by means of a spring (not shown) into position for establishing fluid connection between conduits 23 and 25, while simultaneously connecting conduit l6 with the conduit 24. A solenoid 21 isadapted, when energized, to shift the valve member 26 into position for establishing fluid connection between the conduits l6 and 23, while simultaneously connecting the, conduits and 25 with each other. e

The tank 22 is also connected with a con,- duit 28 comprising a pressure-relief valv 29 which may be by-passed by a conduit 39 comprising a check valve 3|. The conduit 26 communicates with a conduit 32 leading to the blank holder cylinders l6. Mounted on the blank holder platen i4 is a hollow blank holder plunger 33 adapted to enter a work 'piece 34 to be drawn and to clamp the same against a die 35.

Extending through th blank holder plunger 33 and connected to the main platen I3 is the drawing plunger 36 'for drawing a portion of the work piece 34 into the die 35. The work piece 34 is fed into the path of the drawing plunger 36 by means of a feeder, generally designated 31, and shown in detail in Figures 4, and 6, while only diagrammatically indicated in Efigures 1 and 2.

Referring to Figure 4, the feeding mechanism 31 is mounted upon the portion 36 of the press bed by means of a bracket 39, connected to the portion 36 in any convenient manner, for instance by screws 46.

The bracket 39 is provided with machined guideways 4| upon which a slide 42 is reciprocably mounted. Associated with the slide 42 is a feed cup 43 mounted upon arms 44, which are pivoted to the slide 42 by means of pivots 45. The arms 44 are urged upwardly against the slide 42 by springs 46 mounted upon cap screws 41. This construction permits the feed cup 43 to yield in a downward direction through a limited distance, thus enabling the withdrawal of the feed cup from the machine beneath the work piece when the latter has been clamped by the tubular blank holder plunger 33 against the die 35.

The feed cup slid 42 is reciprocated in the guideways 4| by means of a double-acting piston 46 which is reciprocably mounted in a cylinder 49. The cylinder 49 is integral with or in any desired manner connected to the bracket 39.

' In order to provide a control and proper timing of the-operation of the feeding mechanism 31', the electrical control system of the press is provided with a normally open limit switch 66 ply line' 66a.

supply line 66a is the solenoid 21 which, by clo- 5 upon by the drawing plunger 36 and to be enga'ged by the tubular blank holder plunger 33.

The cam 5| is connected to th slide 42 in any convenient manner, for instance by screws 52.

As will be seen from Figure 3, the switch 59,

m when closed, is adapted to establish connection between the solenoid 53 and the conduit 54 which. by closure of switch 55, may be connected with the main supply line 66. One end of the solenoid 63 is always connected with the main sup- Also connected with the main sure of the switch blade 63a pertaining to the solenoid 63, may be connected with the main supply line 56.

Q0 A second switch -blade 63b is adapted, when closed, to connect the solenoid 53 with main supply line 66 throughihe normally closed limit switch 93 which is adapted to be opened by the *arm Ila of the main platen i3.

2 The feeding mechanism 31 is provided with a 30 ing side members which in turn are pivotally mounted upon the supports 63 and 64 secured to the bracket 36. This construction enables the bottom and top members 6'! and 66 to be spaced relatively to each other by a distance most suitable to the particular work piece being drawn, this distance being adjustable by means of the adjusting screw 66 which passes through 9. lug 66 and'is held thereagainst by a lock nut 61.

The forward end of the top member 66 is pro- The cylinder 49 of the feeding mechanism 31 is provided with pressure fluid from a pilot pump 69 for advancing and retracting the feed cup 43. Normally, the pilot pump 66 is structurally united with the main pump l1. and driven by a motor common to both. However, for the sake of clarity, Figures 1 and 2 show the pilot pump 69 separated from the main pump l1.

The pilot pump 69 has its suction side connected to the conduit 2|, while its pressure side is connected by means of conduit 16 with a fourway valve ll. Also connected with the four-way valve II is a conduit 12 leading to the tank 22. A conduit .13 comprising a shutoif valve 14 has one end connected to the four-way valve 1|, while its other end communicates with one end of the feeding cylinder 49. The opposite end of the feeding cylinder 49 communicates with a conduit I6 comprising a check valve 16, and likewise connected to the four-way valve H.

The valve H comprises a valve member II which, by means of spring I6, is continuously urged into position for establishing fluid connection between the conduits l6 and. 1.3, while 70 simultaneously connecting conduits l2 and 15.

However, when actuated by, a cam member 13, the valve member 11 is shifted into position for establishing fluid connection between the conduits l0 and 15, while simultaneously interconnecting the conduits l2 and I3.

The cam 19 is rigidly connected to a control rod 80, having adjustably connected thereto a collar 8i adapted to be engaged by a sleeve 82 car ried by an arm 83 which, in its turn, is connected to the main platen I3. Also connected to the control rod 88 is a second cam 84 with a groove 88, while a compressible spring88 is interposed between the collar 82 and the cam 84. The cam 84 is adapted to engage a valve member 81 pertaining to a two-way valve 88, so as to establish fluid connection between a conduit 89 communicating with the valve 88 and the conduit 15, and a conduit 83 comprising a shutoff valve 9| and leading to the conduit 15. When the valve member 81 is not engaged by the cam 85, the

spring 82 shifts the yalve member 81 so as to interrupt fluid connection between the conduits 53 and 90.

Referring now to the embodiment shown in figure '1, the same differs from that of Figures 1 and 2 in that the valve 88, instead of being operated by the cam 84, is replaced by a valve 88a, which is fluid pressure operated. The parts of Figure 7 corresponding to those of Figures 1 and I 2 are, therefore, designated with the same ref- Operation Assuming that all parts of the press occupy the position shown in Figure 1, and that the pumps I1 and 69 are running, the operator, in order to start a working cycle of the press shown in Figures 1 and 2, closes the switch 55.

Since, in the position of Figure 1, the switch 58 is closed, closure of the switch 55 causes current to flow from the main supply line 56 through switches 55, 50 and solenoid 53 to the main supply line 58a. This causes energzation of the solenoid 53 and, as a result thereof, the switch blades 53a and 53b move to their closing position.

Closure of the switch blade 53b establishes a holding circuit for the solenoid 53, which holding circuit comprises the main supply line 58, normally closed limit switch 93, switch blade 53b, solenoid 53 and main supply line 56a. Closure of the switch blade 53a establishes a circuit comprising the main supply line 56, switch blade 53a, solenoid 21 and main supply line 56a, thereby energizing the solenoid 21.

Energization of the solenoid 21 causes shifting movement of the valve member 26 into position for establishing fluid connection between the conduits 23 and I8, while simultaneously connecting conduit 24 with the conduit 25. Pressure fluid from the pump l1, therefore, flows through conduits I8 and 23 into the right end of the main cylinder I and moves the piston II toward the left. Fluid expelled from cylinder I0 passes through conduits 24 and 25 into the tank 22.

Leftward movement of the piston I I causes the main platen I3 and the blank holder platen I4 to advance toward the work piece 34, while the arm 83, connected to the main platen I3, causes the sleeve 82 to engage spring 88 and,'by means of the latter and control rod 80, to move the cam 18 away from the valve member 11. As a result thereof, the valve 1| moves into position for establishing fluidconnection between the conduits 10 and 15, while simultaneously connecting the conduits 12 and 13 with each other. This, however, has no effect at this time, since the check valve 16 prevents fluid in conduit 10 from passing through the said check valve into the feeding cylinder 49, while, at this time, the two-way valve 88 is closed. Shortly after the blank holder platen it has advanced to such an extent that the blank holder plunger 33 clamps the work piece 34 against the die 35 and holds it properly clamped in this position, the sleeve 82 shifts, by means of spring 86, the cam 84 into such a position that the groove 85 comes into alignment with the valve member 81 and causes the latter to click into said groove.

In this position, the valve member 81 establishes fluid connection between the conduits 88 and 88, so that fiuid from the pilot pump 68 now flows through conduits 18, 15, 90 and 89 into the feeding cylinder 49. This fluid acts upon the feeding piston so as to cause the latter to withdraw the feeding cup 43 from beneath the work piece 34 clamped against the die 35, and to move the feeding cup 43 into the position shown in Figure 4. During this movement, a new work piece slides from the chute 31a into the cup 43.

As soon as the feeding slide 42 begins its retraction stroke, the cam 5I releases the switch 50, so that the latter opens. However, this has no effect on the energization of the solenoid 53, since the latter is held energized by the holding circuit comprising the main supply line 56, switch blade 53b, solenoid 53 and main supply line 56a. The piston II, therefore, continues its advancing movement and causes the drawing plunger 35 to engage the bottom of the work piece 34 and to draw the same into the die 35. If the clamping pressure in the blank holder cylinders I8 exceeds a predetermined value, the excessive pressure is released through the pressure relief valve 29 into the tank 22; 3

When the drawing plunger 38 has reached the end of its drawing stroke, the platen arm I3a engages the switch 93 so as to open the same, thereby breaking the holding circuit for the solenoid 53. As a result thereof, the solenoid 53 becomes deenergized and the switch blade 53a opens, thereby deenergizing the solenoid 21.

The valve member 25 of the four-way valve I9 now moves into position for establishing fluid connection between the conduits 24 and I8, while simultaneously connecting the conduits 23 and 25. Fluid from the pump I1, therefore, now passes through conduits I8 and 24 into the left end of the main cylinder I0 and moves the piston II with the piston rod I2 and main platen I3 toward the right. This also causes rightward movement of the blank holder I4, which is prevented by means, such as connecting rods (not shown in the drawings) from being disconnected fromthe platen I3. In this way, the drawing plunger 36 and blank holder plunger 33 are withdrawn from the work piece, which may now be removed.

During this retraction stroke of the main platen I3, the suction effect created in the cylinders I6 causes fluid to flow from the tank 22 through the check valve 3| into the cylinders I6 and fill the same with fluid. a

, The retraction stroke of the blank holder platen I4 is limited by the stop 84, while the retraction stroke of the press piston I I is limited by engagement of the piston portion 95 with the right end of the main cylinder I0. When the piston I I has reached this position, the cam I9 on the rod 80 has been moved by the arm 83 and collar II into the position shown in Figure 1, in which position the valve member 11 is actuated so as to again establish fluid connection between the conduits 10 and 13, while fluid connection is established between conduits l and 15. Therefore, fluid from the pump, 89 again flows through conduit 13 into the feeding cylinder 49 in the manner described above, and moves the slide "with the cup 43 again into the path of the drawing plunger 36. The press is now ready for a new cycle.

While, for the sake of simplification, the limit switch 93 has been described as position actuated, it is, of course, understood that, if desired, the switch 83 may also be pressure operated and form a part of a pressure responsive device, such as a so-called tonnage control valve, for instance, of the type disclosed in U. S. Patent 2,224,957 to Ernst.

It is furthermore to be understood that, while the cycle of the press, as described above, is semi-automatic, the press may also be operated fully automatically. In this instance, it is merely necessary to provide a linkage which is actuated by the press platen at the end of its retraction stroke for closing the switch 55.

With regard to the operation of the embodiment shown in Figure 7, the latter is substantially the same as described in connection with Figures 1 and 2. However, when, according to Figure '7, the clamping plunger 33 has clamped the work piece 34 against the die 35 and a predetermined pressure has built up in the clamping cylinders Hi, this pressure is conveyed through conduits 32 and 98 to the cylinder 91 where it acts upon the piston 9G, thereby shifting the valve member 81a into position for interconnecting the conduits 89 and 90. Fluid pressure from the pilot pump 69 will then be conveyed to the cylinder 49 in the manner above described. The remainder of the working stroke is then carried out as previously described. When the main platen I3 starts its retraction stroke. the 'pres-' sure in the clamping cylinders l6 drops beyond the predetermined pressure for actuating the piston 96, so that the spring-82 returns the valve member 81a to its initial position.

It will 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 my invention, what I claim as new and desire to secure by Letters Patent, is: I

1. In a hydraulic press, a reciprocable press plunger for exerting shaping pressure on a work piece, a press bed, a die supported by said press bed for cooperation with said plunger, a work piece feeder, a work piece support yieldably connected to said feeder and movable thereby for feeding a work piece into the path of said plunger and holding said work piece between said die and said plunger, motor means operable to reciprocate said feeder, clamping means for clamping said work piece against said die while said work piec is supported bysaid work piece support, and means including 'a switch, an electric circuit containing said switch and a valve controlling the supply of fluid to said motor means and operated by a solenoid in said ciring said motor means to reverse the movement a of said feeder to withdraw said work piece support from said work piece while said plunger continues its movement toward said die.

2. In a hydraulic press, a reciprocable press plunger for exerting shaping pressure on a work piece, a die arranged in alignment with said plunger for cooperation with the latter, a work piece feeder comprising a slide and-e, work piece support, said slide being operable to move a work piece in said support into the path of said plunger between the latter and said die and to hold said work piece in this position, fluid operable means associated with said slide for se lectively causing the same to perform a feeding or a retracting stroke, clamping means operatively connected with said plunger for clamping said work piece against said die, while it is in said support, said clamping means, when in clamping position, preventing said support from being retracted in the same plane in which the feeding movement thereof is effected, and means yieldingly connecting said support to said slide to allow said support, in response to a retracting movement of said slide, to pass about said work piece.

3. In a hydraulic press, a movable press plunger, a die for cooperation with said plunger for exerting a shaping action on said work piece, hydraulic means for reciprocating said press plunger, 9. work piece feeder, a work piece support yieldably connected to said feeder and adapted to fully support a work piece, said work piece support being operable by said feeder so as to move a work piece on said support into a position between said die and said plunger, a switch responsive to the movement of a work piece by said feeder substantially into the'said position, an electric circuit including said switch, a solenoid in said circuit and a valve actuated thereby for causing said plunger moving means 1 to initiate a working stroke of said plunger,

and hydraulic means for withdrawing said work piece support from said work piece while the latter is subjected to pressure created by said plunger.

4. In a hydraulic press, a reciprocable press plunger, a fluid source adapted to supply pressure fluid to said plunger for actuating the same, a work piece feeder comprising a slide and a channel or trough shaped work piece holder yieldably connected to said slide and adapted to support a work piece, said work piece holder being movable selectively into feeding position for placing a work piece on said work piece holder between said plunger and a work piece support, clamping means associated with said plunger for clamping said work piece against said support, a valve for controlling the supply of pressure fluid from said fluid source to said press plunger, a switch responsive to the arrival of said work piece feeder at a location near its feeding position, an electric circuit containing said switch, and a solenoid for actuating said valve to cause said press plunger to move into engagement with the work piece in said feeder to shape said work piece, and an electric circuit including a switch, a solenoid, a valve, and a piston controlled by said valve and. connected to the feeder, said switch being operable in response to the movement of said clamping 'means withdraw said feeder from said work piece while said plunger completes its working stroke.

5. In a hydraulic press, a reciprocable press plunger, a fluid source adapted to supply pressure fluid for operating said press plunger, a work piece feeder adapted to receiveand carry a work piece, hydraulic means for moving said feeder into 'feeding position so as to hold a work piece carfor effecting a forward stroke of said press plunger, and means responsive to a predetermined travel of said plunger during said forward stroke for actuating said feeder-moving means to withdraw said feeder from said work piece while said plunger continues said forward stroke.

6'. In a hydraulic press, a reciprocable press plunger, a fluid source adapted to supply pressure fluid for actuating said press plunger, a work piece feeder having a yieldable work piece holder for selectively placing a work piece into the path of said press plunger, said work piece holder being adapted to act as sole supporting means for said work piece and to hold the same in lifted position during the 'flrst portion of the working stroke of the press plunger, clamping means for clamping said work piece in said lifted position while the work piece is still supported by said feeder, a hydraulic ram for reciprocating said work piece feeder, a hydraulic circuit for supplying pressure fluid to said ram, a valve, an electric circuit containing a switch and electrical devices for actuating said valve, said switch being operable in response to the travel of said press plunger, said valve provided in said circuit for controlling the distribution of said pres.- sure fluid to said ram and thereby the movement of said feeder in one or the other direction.

7. In a hydraulic press, a press plunger, hydraulic means for moving said press plunger, a work piece feeder for moving a work piece into the path of said press plunger and acting as sole supporting means for said work piece during a predetermined portion of the pressing stroke of aid plunger, means for reciprocating said work piece feeder, clamping means responsive to the travel of said press plunger for clamping said work piece while in said feeder against a work piece support, means responsive to the completion of said clamping operation for withdrawing said feeder from said work piece, means controlled .by said press plunger forcausing a feeding operation of said feeder, and electric means associated with said feeder and responsive to the feeding position thereof for starting a pressing operation of, said press plunger.

8. In a hydraulic press, a press plunger, means for reciprocating said press plunger, a press bed, a die supported by said bed, a work piece feeder comprising a work piece holder for moving a work piece into a position between the latter and said die while supporting said work piece in this position, clamping means for clamping said work piece against said .die, means for conveying pressure to'said clamping means for actuating the same so as to clamp said work piece against said die, and control means responsive to a predetermined clamping pressure exerted by said clamping means upon said work piece for withdrawing said work piece holder from said work piece without affecting the movement of said press plunger.

JOHAN A. MUILER.

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