US3124091A

US3124091A - williamson

Info

Publication number: US3124091A
Authority: US
Publication date: 1964-03-10
Anticipated expiration: 1981-03-10

Description

Mmh 1o, 1964 Filed Feb. 9, 1961 F. M. WILLIAMSON RAM TYPE PRESS 2 Sheets-Sheet 1 vBY March 10, 1964 F. M. WILLIAMSON 3,124,091v

RAM TYPE PRESS Filed Feb. 9, 1961' v 2 sheetssneet 2 4d INVENTOR.

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United States Patent O 3,124,091 RAM TYPE PRESS Floyd M. Wiliimnson, 452 Lakewood, Detroit 15, Mich. Filed Feb. 9, 1961, Ser. No. 88,092 6 Claims. (Cl. 113-45) This invention relates to a ram type press and particularly to a die actuated by the press and adapted to perform multiple operations on a workpiece in a predetermined sequence upon each working stroke of the ram.

The present invention provides a die consisting of a plurality of die members at least some of which are provided with a hydraulic cushion so as to provide a predetermined resistance to movement of such die members whereby the several die members perform their respective operations on the workpiece in a predetermined sequence during a single stroke of the press. lt has heretofore been proposed to perform multiple operations in sequence in one working stroke of the press ram, but the prior systems have required the use of additional power from a source other than the movement of the ram of the press. The prior arrangements therefore required additional equipment such as pumps or boosters and also required critical timing of the operation of the additional power source. These and other disadvantages attendant upon use of an outside power source are eliminated by the present invention.

A principal object of the invention is to provide a new and improved hydraulic control system for the dies in a ram type press. Y

A further object of the invention is to provide a die arrangement for a press which is adapted to perform multiple operations in sequence on the Work during each stroke of the press.

Another object of the invention is to provide a die having a plurality of relatively movable die members and a hydraulic control system for the die members adapted to cause them to perform their respective operations on a workpiece in a predetermined sequence during each stroke of the press.

Other and further objects of the invention will be apparent from the following description and claims and may be understood by reference to the accompanying drawings, of which there are two sheets, which by way of illustration show a preferred embodiment of the invention and what I now consider to be the best mode of applying the principles thereof. Other embodiments of the invention may be used without departing from the scope of the present invention as set forth in the appended claims.

In the drawings:

FIG. 1 is a sectional schematic view of a die and a control system therefor constructed according to the present invention; and

FIGS. 2, 3 and 4 are sectional views illustrating a sequence of operations being performed by a die like that shown in FIG. 1.

In FIG. l there is disclosed a die comprising a lower die shoe 10 and an upper die shoe 12, which is adapted to be reciprocated by the ram 14 of the press. The lower die shoe is provided with a forming die 16, an annular cut-olf die member 18 and a stop plate 2i). The cut-oil1 die 18 is provided with a shoulder 22 at its lower end which is adapted to reciprocate within cooperating recesses 24 formed on the die member 16 and the plate 20. The plate is provided with a shoulder 26 which limits upward movement of the die member 18.

The upper die shoe 12 is provided with a cut-off die 2S, a forming die 30 and an annular forming die 32 arranged in opposed relation to the lower die member 18 and provided with an enlarged shoulder 34 adapted to engage the bottom 36 of the annular cavity deiined between the lee die members 23 and 39 to limit movement of the die member 32 relative to the die

members

28 and 30.

The lower die member 18 is provided with a hydraulic cushion consisting of a series of pistons 4i) disposed in cylinders 42 in the lower die shoe 10. The upper forming die 3) is provided with a hydraulic cushion consisting of one or more pistons 44 working within cylinders 46 in the upper die shoe 12. The upper die member 32 is also provided with a similar hydraulic cushion consisting of pistons 48 working within cylinders Sii formed in the upper die shoe 12.

The hydraulic control system for the

movable die members

13, 30 and 32 includes a tank 52 containing hydraulic fluid under relatively light pressure supplied through a line 54 connected to a suitable source of air pressure. The hydraulic iluid is maintained at a pressure of 7() to 10() lbs. per square inch, for example. A line 56 leads from the lower end of the tank 52 to a valve unit 58 which includes passages 6b and 62. The passage 62 is normally closed by a check valve 64 past which the hydraulic iluid is supplied from the tank to passages 66 and 68 to a line '79, which communicates with a passage 72 in the upper die shoe 12. Each of the cylinders 46 and 50 is supplied with hydraulic fluid from the tank 52 past the check valve 64 to hold the die members 3) and 32 in their extended positions shown in FIG. 2.

The cylinders 42 in the lower die shoe 10 are supplied with hydraulic iluid from the tank 52 through a line 74 leading to a valve unit 76 which includes a passage 78 intersected by a passage 8?, which is normally closed by a check valve S2 and passages S4 and 86 connected to a conduit 35. A line 9i) communicates with conduit 88 and is connected to the cylinders 42 so that hydraulic iluid under pressure is supplied from the tank 52 past the check Valve $2 to the cylinders 42 to force the pistons 4t? upwardly to hold the die member 18 in its extended position.

The passages @i5 and 6i? in the valve unit 58 comprise a by-pass around the check valve 64 through which hydraulic fluid is returned from the cylinders 46 and 50 back to the tank 52. A pressure relief valve 92 normally closes the by-pass and is held in its closed position by a spring 94. An adjusting screw 96 engages the spring 94 so that the pressure at which the valve 92 will open may be adjusted at any predetermined value.

The valve unit '76 is also provided with a by-pass around the check valve 82 therein and such by-pass comprises a conduit 9S connected to the line 99, a passage 160 normally closed by a pressure relief valve 162, the passage '78 and line 74. The pressure relief valve 162 is closed by a spring 194, the force of which may be adjusted by a screw 106 so that the valve 102 will open when a predetermined pressure is reached in the cylinders 42.

When the ram of the press is raised, the cylinders 46 and 5h will be supplied with hydraulic iluid through the valve unit 58 to force the pistons therein downwardly, thereby to hold the die members 39 and 32 in their extended positions as shown in FIG. 2. The cylinders 42 will be supplied with hydraulic iluid throughl the valve unit '76 to force the pistons 4b therein upwardly to hold the die member 1S in its extended position. As the ram descends, the work is clamped between the upper die member 32 and the lower die member 18. The pressure relief valve 1192 is set to open at a pressure suilicient to hold the lower die member 1S in its extended position as the ram descends further so that the cut-oilC die 28 trims the work to size as the ram moves to the position shown in FIG. 3. During this movement of the ram the upper die member 22 is retracted, forcing the pistons 48 upwardly within cylinders 51D and forcing the hydraulic fluid back through the line 7@ and passage o8 past the pressure relief valve 92 to passage d@ and line 56. During this movement of the ram, the piston holds the forming die Sil in its extended position so as to form the work into the die ld in the ianner shown in FlG. 3.

Continued movement of the ram forces the die member 3d to its retracted position, forcing the hydraulic fluid from the cylinder back to the tank 52 past the pressure relief valve E32. As soon as the head 34 on the upper die member f2 is engaged by the underside of the die shoe l2, continued downward movement of the ram will cause the lower die member i8 to be retracted,.thcre by increasing the pressure in the cylinders l2 until the pressure relief Valve lil?. opens, whereupon the hydraulic fluid is forced hack to the tank past the valve M2. During this movement of the ram, the die members 3.. and 1S move as a unit while the die members lo and 3i) are stationary so that the peripheral edge of the work is curled over in the manner shown in HG. 4, thus performing a further operation on the work.

A part of the hydraulic fluid discharged from the cylinders l2 through the lines El() and 93 will flow through passage llt? in the valve unit 7&5 into a bore M2 containing a spool valve 1M having a reduced diameter portion around which the fluid flows to a passage lite from which the flows through passage rIlS to the righthand end of the bore lf2 to force the spool valve H4 to the left so as to close the passage Sti. As soon as the passage ll is closed, as the spool valve ld moves to the left, the ruid will flow through a passage l2@ past a check Valve therein and through passage MS to the end of the bore H2 to effect continued movement of the valve Irl-fi against the spring E22. After the ram has completed its working stroke and begins to raise, hydraulic fluid will flow from the tank 52 past the check valve 64 to the cylinders do and Sd to force the die members 39 and 32 to their extended positions. However, since the valve 15.4 has closed off passage Si), the cylinders e2 will not immediately be supplied with hydraulic fluid upon opening of the press. The valve lillfl therefore provides a time-delay device for preventing return movement or the die member 18 to its extended position until the valve 1M returns to its right-hand position under the force of spring 122. The valve lll/lcannot shift to the righthand end of the bore until the hydraulic fluid trapped therein escapes through passage l past a bleeder valve 124, which may be adjusted to provide the proper restriction of passage M3 to obtain the desired time delay in the refilling of the cylinders 42. As soon as the valve 1M opens the passage Sil, the hydraulic fluid will iiow past check valve to the cylinders 52, thereby urging the pistons lt@ and the die member i8 upwardly to strip the work from the die. The scrap resulting from the trimming of the work is stripped from the die by a stripper plate 126 which is urged upwardly by a spring 123.

It will be seen that with the present arrangement proper selection of the pressures at which the pressure relief valves 92 and l0?. will open will result in the desired sequence of operation of the various die members carried by the die shoes. The specific operations disclosed and described herein are for purposes of illustration only, and it is apparent that other shapes may be imparted to the workpiece and other operations performed than those disclosed herein.

In the form of the invention described above, the timedelay device is shown as associated with the lower die member 18. It will be apparent that this time-delay feature might be employed in conjunction with any of the hydraulic cushions. The shape of the part to be formed and the operations to be performed on it will in each case determine the sequence of operation of the various die members and which, if any, of the die members should have a time-delay mechanism of the type described associated therewith. lt will also be apparent that a separate pressure relief valve may be associated with each hydraulic cushion or that two or more of the 4. hydraulic cushions may exhaust through tA e same pressure relief valve, depending upon the seque ce of operations desired.

The time-delay valve disclosed herein forms the subject matter of my Patent No. 2,901,238, issued August 25, 1959.

While I have illustrated and described a preferred embodiment of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

l. In a ram type press adapted to perform multiple oserations in sequence on a workpiece during the working stroke of the ram and wherein the press is provided Vith a first set of relatively movable first and second retractable dies arranged to successively engage the workpiece and an opposed second set of relatively movable first and second dies arranged to successively engage the workpiece as the ram moves to closed position,Y a hydraulic cushion for the first die of the first set which is first to act on the workpiece and a hydraulic cushion for the first die of the second set which is first to act on the workpiece and is retracted as the ram moves to its closed position, each of said cushions comprising a cylinder and piston normally reacting against its respective die, a tank containing hydraulic fluid under pressure, hydraulic fluid connections between said tank and cylinder through which hydraulic fluid is supplied to said cylinder to react against the piston therein to bias the die associated therewith to its extended position, and a pressure relief valve in said connections operable to provide a predetermined resistance to displacement of hydraulic fluid from the cylinder associated therewith due to closing of the press ram so as to provide a predetermined resistance to retractile movement of the die associated with such cylinder, the pressure relief valve of the hydraulic cushion associated with the die of the first set being set to open at a lower pressure than the pressure relief valve of the hydraulic cushion associated with the first die of the second set so that as the opposed dies successively engage and act on the workpiece as the ram moves to its closed position the dies of the first set will be successively retracted before the retraction of the first die of the second set, said first die of the second set while held in its extended position by its hydraulic cushion, and its opposite die while being retracted, being arranged so as to clamp the workpiece therebetween while the second die of the first set engages the workpiece and cooperates with its opposed die to form the workpiece as the ram moves toward closed position, said first die of said second set being positioned after the retraction of the dies of the first set so that said first die of the second set will be moved by the ram against thc resistance provided by its hydraulic cushion and cooperate with its opposed die while the workpiece is held by the other dies of said sets to form the edge of the workpiece downwardly into a curl below the metal of the workpiece held by the adjacent edges of said other' dies as the ram moves to its closed position.

2. Apparatus according to claim 1 wherein said first set of dies is mounted on the press ram.

3. Apparatus according to claim 1 wherein said first die of said second set is shaped for cooperation with said second die of the first set to shape the edge portion of the workpiece into a precurl form as said workpiece is formed by the second dies of the two sets, and wherein said first die of said second set and its opposed die cooperate to form and curl said precurl form into a hollow bead.

4. Apparatus according to claim 1 wherein said first set of dies includes a cut-off die cooperable with a cutedgc on said first die of said second set to trim the workpiece prior to the aforesaid forming operations.

5. Apparatus according to claim l wherein a time delay valve is disposed in the hydraulic fluid connections of the hydraulic cushion for the first die of the second set, said time delay Valve being operable to delay the supply of hydraulic uid to the cylinder of such cushion for a predetermined time interval after the press ram begins to open.

6. Apparatus according to claim 1 wherein said hydraulic cushion for said rst die of said rst set includes a cylinder and piston reacting against the second die of said first set for biasing said second die to its extended position.

References Cited in the le of this patent UNITED STATES PATENTS

Claims

1. IN A RAM TYPE PRESS ADAPTED TO PERFORM MULTIPLE OPERATIONS IN SEQUENCE ON A WORKPIECE DURING THE WORKING STROKE OF THE RAM AND WHEREIN THE PRESS IS PROVIDED WITH A FIRST SET OF RELATIVELY MOVABLE FIRST AND SECOND RETRACTABLE DIES ARRANGED TO SUCCESSIVELY ENGAGE THE WORKPIECE AND AN OPPOSED SECOND SET OF RELATIVELY MOVABLE FIRST AND SECOND DIES ARRANGED TO SUCCESSIVELY ENGAGE THE WORKPIECE AS THE RAM MOVES TO CLOSED POSITION, A HYDRAULIC CUSHION FOR THE FIRST DIE OF THE FIRST SET WHICH IS FIRST TO ACT ON THE WORKPIECE AND A HYDRAULIC CUSHION FOR THE FIRST DIE OF THE SECOND SET WHICH IS FIRST TO ACT ON THE WORKPIECE AND IS RETRACTED AS THE RAM MOVES TO ITS CLOSED POSITION, EACH OF SAID CUSHIONS COMPRISING A CYLINDER AND PISTON NORMALLY REACTING AGAINST ITS RESPECTIVE DIE, A TANK CONTAINING HYDRAULIC FLUID UNDER PRESSURE, HYDRAULIC FLUID CONNECTIONS BETWEEN SAID TANK AND CYLINDER THROUGH WHICH HYDRAULIC FLUID IS SUPPLIED TO SAID CYLINDER TO REACT AGAINST THE PISTON THEREIN TO BIAS THE DIE ASSOCIATED THEREWITH TO ITS EXTENDED POSITION, AND A PRESSURE RELIEF VALVE IN SAID CONNECTIONS OPERABLE TO PROVIDE A PREDETERMINED RESISTANCE TO DISPLACEMENT OF HYDRAULIC FLUID FROM THE CYLINDER ASSOCIATED THEREWITH DUE TO CLOSING OF THE PRESS RAM SO AS TO PROVIDE A PREDETERMINED RESISTANCE TO RETRACTILE MOVEMENT OF THE DIE ASSOCIATED WITH SUCH CYLINDER, THE PRESSURE RELIEF VALVE OF THE HYDRAULIC CUSHION ASSOCIATED WITH THE DIE OF THE FIRST SET BEING SET TO OPEN AT A LOWER PRESSURE THAN THE PRESSURE RELIEF VALVE OF THE HYDRAULIC