US2541534A - Hydraulic press - Google Patents

Description

W. P. MUIR HYDRAULIC PRESS Feb. 13, 1951 4 Sheets-Sheet 2 Filed Jan. 25, 1947 mu v2 3 m@ \u w 5w m u -T x T mo 3 i 1 ow E W W M I 2K m 0.2L 1 1+ u NOM\OI1J m m HNVENTQ \MEQMUJIR ATTORNEYS W. P- MUIR HYDRAULIC PRESS Feb. 13,1951

4 Sheets-Sheet 3 Filed Jan. 25, 1947 /9 INVENTOR W.P MUIR WW2? kg ATTORNEYS W. P. MUIR HYDRAULIC PRESS Feb. 13, 1951 4 Sheets-Sheet 4 Filed Jan. 25, 1947 INVENTOR WPMUIR ATTORNEYS? Patented Feb. 13, 1951 HYDRAULIC PRESS William P.. Muir, Hampstead, Quebec, Canada,

assignor. to Dominion Engineering. Works Limited, Lachine, Quebec, Canada Application January'25, 1947, SerialNo. 724,424

6 Claims. 1

This invention relates to hydraulic presses and particularly to vertical draw-presses in which the work is subjected to a long or deep draw" by means of aring draw-die and a cooperatingpunch.

In vertical draw-presses of conventional design, the punch is rigidly secured to a ram-operated cross-head so that it is always disposed in a vertical position in line withthe opening of a ring draw-die carried by a stationary dieholder rigidly mounted on-the press base. These presses are frequently used for re-drawing operations in which a piece of previously drawn work with a solid end is redrawn to increase its length and decrease its diameter and, wall thickness; Such presses are designed to come to rest with the lower end of the punch positioned above the die a distance greater than the length of the work to be redrawn in order to enable the Work tobe placed on the die and held in a vertical position to receive the punch as the latter travels downwardly on its working stroke. This means that the press daylightf theheight, and the-idle advance or' pre-fill' stroke of the press must be increased beyond reasonable proportions in order to provide for the redrawing of previously drawn work of considerable length. The" excessive increase in the press daylight and height of the press is undesirable in that it involves an excessive increase in the head room required for installation of the press and gives rise to excessive vibration. The accompanying increase in the length of the idle advance or; pre-fill portion of the punch stroke slows down the working cycle of the press to a very substantial degree.

Press daylight is the term applied to the maximum distance between the top face of the press base and the underface of the movable punch-carrying crosshead when the crosshead is at the limit of its upward travel. This distance is the summation of certain dimensions such. as the length of the die holder, the length of the work, the length of the punch, the length of the punch holder by means of which the punch is attached to the crosshead, and certain clearance dimensions. In a conventional draw-press designed fora long draw the press daylight adds up to a large dimension out of all proportion with the other dimensions'of the press and requiring excessive headroom. The idle advance orpre- I fill portion of the working strokeof the punch is increased, with resulting slowing down of the working cycle, as the-clearance between the draw die and the retracted punch is increased to take care of an increase in the'length of the work.

' punch is tiltable from a Verticalworking position in axial alignment with, the draw-die. to. an inclined leading position in which. the lower end of the punch is. displaced to one side of thedraw die and die holder to permit the work; to. be slipped upwardly onto the punch, which is then tilted backto its vertical position to. center the work with reference to the ring draw diethrough which the work is forced by the punch, during the downward or working stroke of the punchcarrying crosshead.

The punch i tilted from its vertical working position to its inclined loading position and viceversa by suitable tilting mechanism which may be automatically or manually controlled. The tiltingmechanism may comprise a cylinder and piston device or other punch tilting means operable toswing the punch about a pivoted axis and preferably includes control means: interlocked with other control elements of the press to make it impossible to effect a working stroke. of the press unless the punch is in its vertical working position.

The inclined loading of the work. onto the punch may be accomplished by hand but, for convenience, rapidity, and safety, is preferably accomplished by'a power-operated manually controlled loading mechanism which functions to slide the workonto the punch and to then actuate a control element which causes the punch tilting mechanism to swing the punch and the work to a. vertical position. in operative alignment with the opening, of the draw die. through which the work is forced by a subsequent downward working stroke of the punch.

The press is also preferably equipped with automatic control means whereby the punch. tilting mechanism is operated to automatically tilt the punch from its vertical working position to its inclined loading position as the punch-carrying crosshead reaches the limit of its upward returnstroke travel.

Other characteristic features and advantages of the invention will be apparent irom the following detailed description of the accompanyin drawings, in which Figure 1 is a view showing the conventional tooling arrangement of a hydraulic draw press of a type to which the present invention relates.

Figure 2 is a view similar to Figure 1 but showing an improved tooling arrangement embodying the essential features of'my invention.

Figure 3 is a diagrammatic view of a complete fluid circuit including the improved tooling arrangement and parts co-operating therewith.

Figure 4 is an enlarged view partly in side elevation and partly in vertical section of my improved tooling arrangement.

Figure 5 is a side elevational view of the arrangement shown in Figure 4.

Figure 6 is an enlarged detailed view of the punch-tilting mechanism shown in the preceding figures.

As shown in Fig. 1, the tooling arrangement of a conventional, vertical, hydraulic draw-press comprises a movable ram-operated crosshead 5 to which a punch 6 is rigidly secured in vertical position by means of a fixed punch holder 1. The punch 6 is centered with respect to the central opening of a ring draw die 8 fitted in the upper end of a stationary die holder 9 rigidly mounted on the punch base It. The punch 6 is shown at the limit of its upward travel and a work-piece II is shown interposed between the lower end of the punch and the draw die 8. The work piece I I is shown as a drawn tubular member having a solid lower end Ha against which the punch acts to force the work-piece downwardly through the draw die to thereby increase the length and decrease the diameter and wall thickness of the work-piece as represented, for example, by the redrawn work-piece l2 appearing directly below the draw die. The press stroke is indicated by the distance line A while the press daylight is indicated by the distance line B.

By virtue of the improved tooling arrange- 'ment shown in Fig. 2, the present invention substantially reduces the press daylight and the length of the idle advance portion of the working stroke of the punch 6 as will be seen by comparing the length of the press daylight distance line B (Fig. 2) with the length of distance line B (Fig. 1). assembling punch 6' with crosshead 5' so that,

in the fully raised or retracted position of the crosshead, the punch is tilted from the vertical working position shown in full lines to the inclined loading position indicated by dotted lines. In the inclined loading position of the punch the lower end thereof is displaced to one side of the draw die 8' and die holder 9 so that work-piece Il may be slid upwardly onto the punch which is then swung to its vertical position to center .the work on the draw die prior to commence- .ment of the working stroke during which the descending punch forces the work downwardly through the draw die to produce the finished drawn work l2 shown beneath the draw die. This pivotal mounting of the punch so that its lower end may be swung to a loading position at one side of the die holder makes it feasible to reduce the press daylight so that, in the fully raised position of crosshead 5, the lower end of the punch is elevated above the draw die a relatively short distance which may be considerably less than the length of work-piece H. It will also be seen that, with the work-piece fitted on the punch and the latter disposed in This is accomplished by its vertical position, the punch makes only a relatively short idle advance before contacting the solid lower end of the work-piece and commencing the draw. This, obviously, speeds up the working cycle as compared with the arrangement shown in Fig. 1 in which the length of the idle advance portion of the working stroke of the punch is greater. than'the length of the workpiece [0.

The mounting of the tiltable punch The upper end of punch 6' (see Figs. 3 to 6 inclusive) is screwed into a pivotally mounted punch holder I5. This holder is provided with trunnions l6 journalled in slide bearings l'i fitted in guideways l 8 provided in a punch holder frame l9 rigidly secured to the underface of crosshead 5'. The bearings H are free to have a limited vertical movement in guideways l8 and are retained therein by bearing plates 20. The punch holder frame I9 is secured to crosshead 5 by stud bolts l9a and nuts i912 so that it may be properly centered by centering screws 25 bearing against the sides of said frame and having screwthreaded engagement with centering posts 22 carried by the crosshead. This enables the punch 6' to be accurately located with reference to the cooperating draw die.

The punch holder i5 is formed witha convexly curved upper surface [5a adapted to bear against a concavely curved bottom floating bearing surface 23 of a bearing block 24 fitted in punch holder frame I9. Bearing block 24 is also formed with a convexly curved upper bearing surface 25 adapted to bear against a concavely curved bottom bearing surface 26 of a thrust block 21 which is also fitted in frame [9 and is provided with a flat upper surface for contact with the lower surface of crosshead 5. The curved bearing sur-. faces 15a, 23, 25 and 26 are arranged to permit self alignment of the punch 6 and punch holder 15 by movement thereof in different paths at right angles to each other. In this connection it may be explained that the direction of curvature of the engaging bearing surfaces I50. and 23 of punch holder [5 and floating bearing block 2 is at right angles to the direction of curvature of the engaging bearing surfaces 25 and 2G of bearing block 24 and thrust block 2?. It may also be noted here that the self-aligning movement of the punch occurs when the latter is under load and the trunnion slide bearings I? are raised clear of their retaining plates 29 so that the upward thrust of the punch is taken by the curved bearing surfaces of the punch holder I5, floating bearing block 2 3, and thrust block 21.

When punch 6' is placed under load, the bearings I! move upwardly in the guideways l8 so that the thrust, instead of being taken by said bearings, is transmitted directly to the crosshead 5 through punch holder l5, bearing block 24 and thrust block 21.

The punch tilting mechanism Punch 6' is tilted from its vertical working position to its inclined loading position and viceversa by tilting mechanism comprising tilting lever 29 having one end rigidly secured to punch holder 15 and the other end pivotally secured, by clevis 3|], to the piston rod 3! of a piston 360. (Fig. 3) working in cylinder 32 which is mounted on crosshead 5 by bearing bracket 33.

Cylinder 32 is connected in an air circuit, hereinafter described, so that when crosshead 5 reaches the upper limit of its travel air is supplied. to the upper end and exhausted; from the lower end of said cylinder to cause. the piston working therein to travel downwardly and thereby tilt the lever 29 and punch holder [5 to swine punch 6 from its vertical Working position to its inclined loading position.

After the work I! has been loaded onto the inclined punch 6', the routing of air to and from cylinder 32 is reversed, as hereinafter explained, so that air is exhausted from the upper end and supplied to the lower end of said cylinder to effect upward movement of piston operating therein to thereby swing the punch 6' to its vertical working position. Following this, fluid is supplied to the working cylinder of the press to effect a downward or working stroke of the ram to which crosshead 5' is attached. Thepunch, descending with the crosshead, forces the work down.- wardly through the draw die.

An adjustable stop screw 34 is threaded upwardly through a stop bracket 35 fastened to a side of punch holder [5 directly opposite the side to which tilting lever 29 is attached. This stop screw is engageable with a cooperating stop 36 of punch holder frame I9 to limit tilting movement of the punch holder and punch in one direction. Hardened stop plugs 3'! are fitted in punch holder frame 19 and tilting lever 23 to limit swinging movement of the punch holder and punch in the opposite direction. An adiusting screw 39a is threaded upwardly through lever 29 to provide for adjustment of the stop plug El carried by said lever.

A switch trip lever 38 is fixed to one of the trunnions it of punch holder I5 and functions to close a valve-controlling micro switch 39 when the punch 6' is tilted to its vertical working position. Switch 39 is supported by switch bracket is attached to crosshead 5' and opens automatically when punch 6 is tilted to its inclined work receiving position.

The work loading mechlanism The loading of work I l onto punch 6 may be accomplished by hand but is preferably accomplished by a manually controlled, power actuated, work loading mechanism generally indicated at 4|. This mechanism comprises a loading head 42 arranged to slide along an inclined loading bracket 43 provided with guides 43 between which the loading head is positioned. The loading bracket 43 is carried by die holder 9 and the surface over which the loading head travels is inclined so that the loading head is in axial alignment with punch 6' when the latter is in its inclined loading position. The loading head 62 is screwed onto the upper end of a piston. rod 35 having its lower end fastened to a piston 46 (Fig. 3) working in a loading cylinder 4"? mounted on the inclined loading head supporting surface of loading bracket 43.

When the press is at rest with punch 6" in its inclined loading position, the piston operating in loading cylinder 5? is at the lower end ofv said cylinder and the loading head 52 is in the lowered position. as shownin Figs. 2 and 3. The work. i l is then placed on loading head 62' so that it is supported by the inclined guiding surface of loading bracket 43. Air is then supplied, as hereinafter described, to the lower end of loading cylinder t! to raise the loading piston and the loading head 32 to thereby slide the work i l upwardly onto the inclined punch 6-. As the loading head :22 reaches the. upper limit of. its. travel fluid connections are established" whereby air is supplied 6 to the lower end and exhausted from the upper end of punch tilting cylinder 32 to cause the piston working therein to travel upwardly and thereby tilt the lever 29 and punch holder to swing punch 6 to its vertical working position.

The air circuit This circuit (Fig. 3) includes a main air supply line 60 connected to a pump or other suitable source of compressed air. From this supply line air is routed to punch tilting cylinder 32 through line 6!, four-way pilot-controlled reversing valve 62, telescopic line 63, connected to the upper end of said cylinder and telescopic line 64 connected to the lower end of said cylinder.

Air is supplied to the lower end of punch-tilting cylinder 32 through line 64 and exhausted from the upper end of said cylinder through line 63 when reversing valve $2 is shifted to the right by pilot air pressure supplied through pilot line 65, automatic loading-head actuated pilot valve 66, and pilot line 61. Air is supplied to the upper end of cylinder 32 through line 63 and is exhausted from the lower end of said cylinder through line 64 when reversing valve 62 is shifted to the left by pilot air pressure supplied through pilot line 68-, automatic crosshead actuated pilot valve 6% and pilot line 10. The loading-head actuated pilot valve 66 is opened by a roller cam i! (Fig. 5) on loading head 12 when the latter reaches the limit of its upward travel during the loading of the work onto the punch 6. The crosshead-actuated pilot valve 69 is opened by a cam 12 on crosshead 5 when the crosshead is at the top of its stroke.

Air is routed to loading cylinder 4? from supply line 613 through line 14, four-way pilot controlled reversing valve 15, line 16 connected to the lower end of cylinder 41 and line 11 connected to the upper end of said cylinder.

Air is supplied to the lower end of loading cylinder t1 through line it and exhausted from the upper end of said cylinder through line Ti when reversing valve i5 is. shifted to the left by pilot air pressure supplied from line 63 through pilot lines it and 88', manually operable load buttons 8| and 82 and pilot line 83. Air is supplied to the upper end of loading cylinder 11 through line H and exhausted from the lower end of said cylinder through line it when reversing valve '55 is shifted to the right by pilot air pressure. sup plied from line M through pilot line 85,. automatic cross-head actuated pilot valve 86, and pilot lines 8? and The cross-head actuated pilotv valve 86 is opened by the; cross-head cam 12' when the cross-head has descended a short distance on its working stroke.

Two manually operable load buttons 84 and 82 are provided as a safety measure to compel the operator to use both hands in operating the loading mechanism and thus ensure that the operators two hands will be safely out of the way. The line connection between buttons 55 and. 82 includes a bleed which prevents locked up air permitting the second button alone to start the cycle.

The stroking of the press is controlled by a main. reversibie working valve, not shown, operating in a valve casing 69. This working valve is connected by valve stem 95!, to an operating piston in working in cylinder 92. Air is routed to cylinder-'33 from supply line 5c through. line line. 9% connected to the upper end of cylinder 93 and line 9! connected to the lower end of said cylinder.

Air is supplied to the upper end of the working valve operating cylinder 92 through line 96 and is exhausted from the lower end of said cylinder through line 9'! when valve 95 is shifted to the right by pilot air pressure supplied from line 60 through pilot line 99, solenoid-controlled valve I60, pilot line 69!, non-repeat three-way valve H32, pilot line !03, manually operable start button m4, and pilot line N35. The operating solenoid its of valve I89 is connected to a H volt source ID? of electrical energy through the previously mentioned micro switch 39 which is opened by trip lever 38 when the punch is tilted to its loading position and closes automatically when the punch is swung back to its vertical working position.

Air is supplied to the lower end of working valve operating cylinder 92 through line 9'! and is exhausted from the upper end of said cylinder through line 96 when reversing valve 95 is shifted to the left by pilot air pressure supplied through pilot line 429, automatic pressure operated valve H0, and pilot lines HI and H2. Valve H0 is a normally closed valve which is opened auto-- matically b suitable distance trip means (not shown) when the punch has travelled a predetermined di tance in the working stroke direction.

An air vessel H5 connected to the air supply line 6!] through check valve I IE to provide a supplementary source of compressed air for operating the main working valve of the press in event of failure of the normal air supply.

The previously mentioned pilot line 19 is connected to one end of a cylinder H8 containing a working valve locking piston H9. A piston rod l2!) is connected to piston H9 and is provided at its free end with a latch lZi which engages at times in a notch 90a provided in working-valve stem 9%. Piston H8 is operated to a working valve locking position by air pressure supplied to cylinder E E8 through pilot line 19 and is operated to a working valve releasing position by its biasing spring i22 when line 19 is connected to exhaust through the reversing valve 52 controlling the punch tilting piston 3 l.

A pilot line E24 is connected between the pilot line 83 serving the reversing valve of loading cylinder ll and the pilot lines Ill and H2 serving the reversing valve 95 of the working valve operating cylinder 92.

The pilot line H serving the reversing valve 95 of working-valve operating cylinder 92 is connected, through a normally closed automatic starter valve I26 and pilot line l2! to non-repeat valve H12.

Operation of air circuit and parts associated therewith As previously stated, the press comes to rest with the punch 6 in its inclined loading position and the loading head 42 in its lowered position. The operator places the work on the loading head 32 and then presses the two loading buttons 8| and 82 to open position. Since reversing valve 62 is now positioned to supply air through lin 63 to the upper end of cylinder 32 to hold punch 6 in its inclined loading position, it will be seen that the opening of buttons 81 and 82 results in pilot air pressure being supplied to the right hand end of reversing valve 15 through pilot lines I9 and 80, buttons BI and 82, and pilot line 83,

thereby reversing valve 15 to supply air to the lower end of loading cylinder 41 through pipe 16 and to exhaust air from the lower end of said loading cylinder through pipe 11. The resulting upward movement of loading piston 46 and loading head 42 causes the work I l to be slid upwardly onto the punch 6.

As the loading head 42 reaches the upper limit of its travel, it'opens pilot valve 65 so that pilot air pressure is supplied through pilot line 65,

pilot vave 66, and pilot line 61 to the left hand end of reversing valve 62, which is thus shifted to the right to supply air to the lower end of punch-tilting cylinder 33 through line 64' and to exhaust air from the upper end of said cylinder through line 63, thereby operating piston 3| in an upward direction to swing punch 6 to its vertical operating position in line with drawring 8.

As punch 6' swings to its vertical operating position, the switch trip lever 38 moves against switch 39, thereby closing the latter to energize solenoid I96 and open valve N30 to supply operating air to manually-operable start button IM through line I93 and to automatic start valve I26 through line E21.

If the automatic start valve I26 is open, air will be delivered through this valve and the pilot line I05 to the left hand end of reversing valve 95 and will operate the latter to supply air to the upper end of cylinder 92 through line 95 and to exhaust air from the lower end of said cylinder through line 9?. The resulting downward movement of piston 9| will lower the working valve in valve casing 89 to a position establishing fluid connections through which hydraulic pressure fluid is routed to and from the press ram to ellect a downward working stroke of the punch carrying crosshead 5. If the automatic start valve :26 is closed when solenoid-actuated valve EHO is opened by closure of switch 39, the manually operable start button I04 is opened to reverse valve 95 and effect a Working stroke of the press. When crosshead 5' has descended a short distance on its working stroke, the cross head cam 12 opens pilot valve through which air pressure is delivered to operate reversing valve 15 to a position in which air is delivered to the upper end of loading cylinder 41 and exhausted from the lower end of said cylinder to return the loading head 42 to its starting position.

When punch 6' is at the bottom of its working stroke, valve Hi] is automatically opened by the previously mentioned distance trip means so that pilot pressure is supplied through pilot lines I09, Ill and H2 to shift valve to a position in which air is supplied to the lower end of cylinder 92 and exhausted from the upper end of said cylinder. The resulting upward movement of piston 9i reverses the working valve in valve casing 89 to establish fluid connections through which pressure fluid is routed to and from the press ram to effect an upward return stroke of cross head 5 and punch 6.

When valve [ID is opened, a shot of air is delivered to the loading cylinder reversing valve 75 through pilot lines E26 and 88 to ensure descent of loading head 42 to its starting position. When cross head 5 reaches the top of its return stroke, cross head cam 12 opens pilot valve 59 through which pilot pressure is delivered to shift reversing valve 62 to a position in which air is exhausted through the lower end of punch-tilting cylinder 32 and is supplied to the upper end of said cylinder to tilt punch 6 to its inclined workreceiving position.

I claim:

1. In a hydraulic draw press, a crosshead, a punch holder frame secured to said crosshead, a punch holder pivotally supported in said frame by slide bearings permitting limited bodily movement of the punch holder toward and away from the crosshead, a bearing block and a thrust block slidably arranged in the punch holder frame between the punch holder and the crosshead, said bearing block having curved bearing surfaces engaging complementary bearing surfaces of the punch holder and thrust block between which the bearing block is interposed, the curvature of the engaging bearing surfaces of the punch holder, bearing block, and thrust block being such as to provide for self alignment of the punch and punch holder by movement thereof to pathsat right angles to each other.

2. In a hydraulic draw press, a vertically extended die-holder, a draw-die mounted in the upper end of said die-holder, a vertically movable crosshead arranged to travel toward and away from said die, a tiltable punch pivotally secured to said crosshead for swinging movement from a vertical working position in axial alignment with the draw-die to an inclined work-receiving position in which the lower end of the punch is disposed to one side of the draw-die to permit a work piece to be slid upwardly onto said punch, punch-tilting mechanism for swinging said punch from it working position to its work-receiving position and vice-versa, means for moving said crosshead toward and away from said die, means for operating the punch-tilting mechanism to cause the punch to be disposed in its inclined work-receiving position when said punch is returned to an elevated starting position relative to the draw-die by the punch carrier after completing a working stroke, power actuated punch loading means for sliding a work piece upwardly onto the punch when the latter is in its inclined work-receiving position, and means connected to and actuated by said last mentioned means for operating said tilting mechanism to swing the punch to its working position after the work has been placed thereon and prior to commencement of the downward or working stroke of the punch and crosshead.

3. A draw press comprising a stationary drawdie provided with a vertical opening for the reception of a work piece, a vertically movable punch adapted to receive thereon a tubular work piece open at one end and to force the work piece through the opening of the draw-die during the working stroke of the punch, a vertically movable punch carrier to which the upper end of the punch is pivotally secured for swinging movement about a horizontal axis from a vertical working position in axial alignment with the work-receiving opening of the draw-die to an inclined loading or work-receiving position and vice versa, operating means connected to the punch carrier for raising and lowering same to efiect the working and return strokes of the punch, a punch tilting mechanism connected to the punch for swinging the latter from its vertical working position to its inclined work-receiving position, means connected to the punch carrier and to the punch tilting mechanism to operate the latter to swing the punch to its inclined work-receiving position when the carrier and punch are returned to their starting position following a Working stroke of the punch, power actuated loading means operable to slide a tubular work piece open at one end upwardly onto the punch when the latter is in its inclined workreceiving position and means connected to said punch tilt ng mechanism and operable by and in response to a loading operation 01' said loading means to operate said punch tilting mechanism to swing the punch to its working position after the tubular work piece has been slid onto the punch by said loading means.

4. A fluid actuated draw press comprising a stationary vertically extending die holder, a draw-die carried by said die holder and provided with a vertical opening for the reception of a tubular work piece, an inclined work piece guide carried by said die holder and inclining downwardly and outwardly from the upper end of the die holder, a loading head arranged to slide upwardly and downwardly on said guide, a loading head operating piston connected to said loading head, a cylinder in which said piston works, a reversing valve and pipe connections through which fluid is routed to and from said cylinder to shift the loading head from a starting to a punch loading position and vice versa "dependin on the positioning of the reversing valve, a manually operable control valve and pipe connections through which fluid is routed to operate said reversing valve to a position in which fluid is routed to and from the loading head cylinder to operate the loading head to its punch loading position, a normally closed loading head pilot valve and pipe connections through which fluid is supplied to operate said reversing valve to a position in which fluid is routed to and from the loading head cylinder to operate the loading head to its starting position when said pilot valve is opened, a vertically movable punch adapted to receive thereon a tubular work piece open at one end and to force the work piece through said die during a downward working stroke of the punch, a vertically movable punch carrier to which: the upper end of the punch is pivotally secured to provide for swinging movement of the punch about a horizontal axis from a vertical working position in axial alignment with the work-receiving opening of the die to an inclined work-receiving position and vice versa, operating means connected to the punch carrier for lowering and raising same to effect the working and return strokes of the punch, a punch tilting mechanism comprising a cylinder and piston device connected to the carrier and to the punch for operating the latter from its vertical working position to its inclined work-receiving position and vice versa, a punch tilting mechanism reversing valve and pipe connections through which fluid is routed to and from the cylinder and piston device of the punch tilting mechanism to operate the punch to a working position or to a work-receiving position depending on the positioning of said reversing valve, a normally closed punch control valve and pipe connections through which fluid is delivered to operate the reversing valve of the punch tilting mechanism to a position in which fluid is routed to and from the cylinder and piston device of said mechanism to swing the punch to its inclined workreceiving position, valve actuating mechanism carried by and movable with the punch carrier and arranged to automatically engage and open said punch control valve when the carrier and punch are returned to startin position following a working stroke of the punch, said valve actuating mechanism being also arranged to engage and open the loading head pilot valve when the punch carrier is moved a predetermined distance downwardly from its starting position, the arrangement of the punch and loading head being such that, when the punch is in its inelined working position, it is in axial alignment with the working head to permit the tubular work piece to be slid onto the punch by a load operation of the loading head in response to closure of the manually operable control valve through which fluid is supplied to the loading head operating valve to shift the latter to a loading head operating position, and a loading head actuated valve and pipe connections through which fluid is delivered to operate the reversing valve of the punch tilting mechanism to efiect swinging movement of the punch from its work-receiving to its working position following the sliding of the work piece onto the punch by the loading head, said loading head actuated valve being a normally closed valve arranged to be engaged and opened by the loading head as the latter completes its loading operation.

5. A draw press comprising a stationary drawdie provided with an opening for the reception of a workpiece, a punch adapted to receive thereon a tubular work piece and to force said work piece through said die during a working stroke of the punch, a reciprocating punch carrier to which one end of the punch is pivotally secured to provide for swinging movement of the punch from a working position in axial alignment with said die to an inclined work-receiving position and vice versa, and punch positioning means comprising a cylinder and piston device connected to the punch and to the punch carrier, a reversing valve and fluid circulating conduits connected to said valve and to said cylinder and piston device to providev a, fluid circulating system through which pressure fluid is routed via the reversing valve to and from the cylinder and piston device to actuate the latter to swing the punch from its working to its work-receiving position and vice versa dependent on the position of the reversing valve. 7

6. In a draw press of the type set forth in claim 5 in which the reversing valve is a fluid pressure operated valve, a normally closed punch control valve and pipe connections through which fluid is delivered, in the open position of the control valve, to operate said reversing valve to a position in which fluid is routed to and from said cylinder and piston device to swing the punch to its inclined working position, valve actuating means connected to the punch carrier to travel therewith and arranged to engage and open said punch control valve when the carrier and punch are returned to starting position following a working stroke of the punch, power actuated loading means including a reciprocating loading head arranged to support thereon a tubular work piece open at one end and operable, during the working stroke thereof, to slide the work piece upwardly onto the punch when the latter is in its inclined work-receiving position, a second normally closed punch control valve arranged to be engaged and opened by the loading head during the working stroke of the latter and pipe connections through which pressure fluid is routed to said reversing valve via said second control valve in the open position of the latter to operate the reversing valve to a position in which fluid is routed to and from said cylinder and piston device to swing the punch to its working position following the sliding of the work piece onto the punch by the loading head.

WILLIAM P. MUIR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,582,217 Henry Apr. 27, 1926 1,981,490 Witte Nov. 20,1934 2,001,902 Englebertz May 21, 1935 2,023,879 Friden Dec. 10, 1935 2,125,249 Temple July 26, 1938 2,161,752 Temple June 6, 1939 2,339,019 Le Tourneau Jan. 11, 1944 2,403,183 Lefere July 2, 1946

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