US2441539A - Die cushion - Google Patents

Description

May 11, 1948. H. D. ALDREDGE DIE-CUSHION Filed June 5, 1944 2 Sheets$heet 1 INVENTOR HOWARD D. AL DREDGE ATTORNEYS Patented May 11, 1948 UNITED STATES PATENT OFFICE 441,539 pm CUSHION Howard D. Aldr ga, Din'ton, Ohio Application June 3, 1944, Serial No. 538,567 r This invention relates: to. a hydraulically op.- erated die-cushion that is adapted to. be used on forming presses or punch presses of various types.

An object of the invention is to'provide a diecushion that is constructed and arranged as a unit structure that can be placed upon any forming press to provide a cushion for any part of a die that is supported upon the die cushion.

Another object of the invention is to provide a hydraulically operable die-cushion that is constructed and arranged in the manner of a bolster-plate that can be placed upon any forming press beneath a die member so that any part of the die requiring a cushioning action can be. operably connected to the die-cushion to obtain the desired cushioning action of the die parts.

Still another object of the invention is to provide a unitary structure of a bolster-plate having a hydraulically operated die-cushion associated therewith as a part of the unit structure so that the bolster-plate can be placed upon any forming press and thereby provide a diecushion on substantially any conventional forming press, even though the forming press was not constructed and designed for a die-cushion.

Another object of the invention is to'provide a bolster-plate having a die-cushion therein in accordance with any of the foregoing objects wherein the die-cushion is hydraulically openated, and the fluid system for the die-cushion is wholly contained as a part of the unit structure, whereby the die-cushion can be used on any forming press without requiring external connections to the die-cushion.

Further objects and advantages will become apparent from the drawings andthe following description Y In the drawings:

Figure 1 is a perspective elevational view of a mechanical press upon which the combination bolster-plate and die-cushion of this invention has been placed. V

Figure 2 is a side elevational view,. particularly in cross-section, illustratinetho bolstor plate and die-cushion of this invention. I

Fi ur 3 is an xploded perspective vi w of th bolster-plate and die-cushion of this invention with parts thereof broken away to illustrate the construction thereof.

Figure 4 is a vertical cross-sectional view taken substantially along line dad of Figure 3.

Figure 5 is a cross-sectional view thro gh olsterlate and d oshion, o this invention:

5} Claims. (Cl. 267- 1) ,z- Figure 6 is a cross-sectional view similar to Figure 5 illustrating, them oh nism. n action Figure is an. enlarg d. c o -sectio a vi w taken al ng lin l==l oi F gure 3- e Figure 8 i an de tional view or the diecus hion,- partially in crossesection, illustrating a m difi d arran ment f. a f u d control valv for the operating system of the die-cushion.

The combina ion bo sternlets and die-cushion ,i of this nvention is adapt d to be. applied o an convent nal form ng pr ss wher ver and when ever a diewushion isfldesired to beprovid d u on the forming press. Many f h standa d lin forming presses manufactured today do, not have d1e-cus1ions provided on them- :Iiowo or. i

many instances it is esired t pr duce a iece p n a .forming press or a type that requires a cushioning action to at leas one artof the die to prevent. the m tal. being rormed irom tearin or bein pierced during the i rming operat on However, the standard line r f rming P esses that areuo provided with die-cu h ons uc a piece could not read ly pe form d on hem, houo requiring the nec ssi y or pu chasi g a s ec a forming press, or requ ring the ne e ity of constructing a special d i e thatmay have a cushion incorporated there n i rthe pu os f u ionins the parti ul r el men d i e .In the lat er instance itis necessary to connect the cushionins member with a su tab e flu d ur e orsuplying the required fluid during operation of the cushioning member,

In this invention a special combination bolster plate and die-cushion is constructed as aunitary structure with the fluidactuating system for the die-cushion being an integral part of the combination structure. The arrangement therefore permits placement of the bolster-plate and dieoushion upon any c n ent on press h t s n provided with a die-cushion and t e b pt the standard prossiior ush on ng tio rv ious elements oi a die, The d e c n e constructed in conventionolmaur or w th th u l ins xtendin through th d e fr m he elements t be cushioned, these-pi s. ngaging t die-cushion in the bolstor pl te of this n e ti n or he p n se of cushioning the elements n t d e du in the forming operation- The combination bo t r-p at nd d e-c h on o this invention ge eral in a by th numeral in, is adapted to e used upo a for g p es of any conv nti n l typo n f w ch is illustrated in Fi ure 1,.

The iormi s press consists o a o H ing a bed I 2 that isas aptod t upp a di mber upon the same. The frame II carries the up-rights I3 that support a reciprocating ram I4 that is adapted to carry a punch or die member that cooperates with the die member carried upon the bed I2. The ram I4 is carried upon a crank I5 suitably driven through the pulley flywheel 51 for reciprocating the ram I4.

Under normal conditions the female die member will be supported upon the bed I2, and the male die member carried by the ram I4 so that the metal pieces placed upon the female die member can be formed upon reciprocation of the ram I4. When using the combination bolsterplate and die-cushion of this invention, the bolster-plate is supported upon the bed I2, and then the female die member is placed upon the bolster-plate I0, and the press can be operated in conventional manner and the elements of the die member can be cushioned by the diecushion in a manner. which will be hereinafter described. 7 H V e The die-cushion of this invention consists of a bolster-plate I6 that is adapted to be placed upon the bed of any conventional forming press. The bolster-plate I6 has an opening I I therein that receives the cushion plate I8 of the hydraulically operated die-cushion. The cushion plate I8 is connected to a piston I9 that operates in a cushioning cylinder that has. the cylinder bore 2| which receives the piston I9. A rod 22 extends between the piston I9 and the cushion plate I8 through an end closure wall 23 secured to the cylinder bore 2| to thereby form a closed cylinder chamber. 7

The cylinder 20 is provided with a flange 24 that receives the bolts 25 for securing the cylinder 20 to the lower side of the bolster plate I6. A spring 26 positioned between the piston I9 and the bottom wall of the cylinder 2|] normally holds the piston I9 and the cushion plate I8 in an upward position as illustrated in Figure 5. The spring 26 is of sufl'icient strength to support the parts previously mentioned together with the parts of the die that are to bev cushioned so that they will always be returned to the initial starting position, such as that illustrated in Figure 5.

The bolster plate I6 is adapted to support a die 39, which is secured thereto in any suitable and conventional manner. The die 30 is provided with the die opening 3| which receives the cushioning member 32 that has pins 33 extending therefrom into engagement with the cushion plate I8 of the die cushion. A male forming member 34 carried by the ram I4 is adapted to enter the die opening 3| for forming the work piece 35, the member 32 cushioning the work piece 35 by operation of the die-cushion in a manner hereinafter described.

The bolster plate I6 is provided with a pair of bores 36 and 35a extending through the same. The bore 36 receives the pistons 31 and 31a for reciprocation therein while the bore 36a receives the pistons 38 and 38a for reciprocation therein. The arrangement of each of the pistons 31, 31a, 38 and 38a is the same for each, hence a crosssectional view of only one of the pistons has been illustrated, and is more clearly shown in Figure '7.

The piston 31a that operates within the bore 36 is retained against a stop-shoulder 39provided by a smaller-diameter portion 40 of the bore 36 by means of aspring 4| that is retained in the bore 36 by means of the removable plug 42. The pistons 31, 31a, 38 and 38a are thus retained in a normal predetermined position. The spring 4| may be provided with suitable mechanism for adjusting the degree of compression thereof to change the pressure at which the cushion plate I8 will operate, or the springs can be changed in their respective bores when a pressure change is required for operating the cushion plate |8..

The bore 40 provided between the pistons 3'! and 31a, and the bore 40a provided between the pistons 38 and 38a are inter-connected by means of the passage 43 provided therebetween. The passage 43 is connected to the cylinder bore 2| by means of the passage 44 so that liquid in the cylinder bore 2| can be transferred through the passages 44 and 43 into the bores 40 and 40a to apply pressure against the pistons 31, 37a, 38 and 38a and cause them to move against the springs retaining them in position and thereby cause pressure to be developed in the cylinder chamber 2| that resists downward movement of the piston I9 as illustrated by the resistance of the springs 4|, and thus resisting downward movement of the cushion plate I3 which causes the member 32 to cushion the work-piece 35 during the forming operation.

By controlling the force of the springs 4|, the pressure developed in the chamber 2| can be controlled, or the pressure developed in the chamber 2| can be controlled by means of a restriction valve 59 that has the end thereof protruding into the passage 43 whereby to restrict the flow of liquid from the chamber 2| through the passage 44 into the passage 43. The resistance valve 50 therefore controls the pressure developed in the chamber 2| by regulating the pressure drop between the passage 44 and the passage 43 across the restriction valve 50.

The resistance valve 5|] consists of a stem 45 that has the threaded portion 46 thereon that is received in the threaded recess 41 in the bolster plate I6, the resistance valve 59 extending from the threaded portion 46 of the stem 45. A packing member 48 is provided around the stem 45 to prevent'loss of fluid around the resistance valve 50, and the valve 5|! is moved inwardly or outwardly upon rotating the same by means of the knurled knob '49.

The operation of the device, thus far described, is such that when the ram I4 moves downwardly to cause the punch 34 to engage the work-piece 35, it will be forced downwardly against the member 32, which in turn forces'the cushion-plate I8 downwardly. 'Downward movement of the piston I9 causes liquid in the chamber 2| to be delivered into the bores 40 and 40a in the bolster-plate I6 through the passages 44 and 43. Pressure will build up in the cylinder chamber 2| as determined by the springs 4| or by the pressure drop across the restriction valve 59 to thereby cushion the downward movement of the member 32 and thus support the work-piece 35 during the forming operation.

After the work-piece 35 is formed, as illustrated in Fig. 6, the ram I4 will move upwardly and thereby permit the spring 26 to lift the piston I9. The springs 4| in the bores in the bolster plate IE will also cause inward movement of the pistons 31, 31a, 38 and 38a to return the fluid from the bores 40 and 4011 through the passages 43 and 44 into the cylinder chamber 2|, thus causing the piston I9 to rise and refill the cylinder chamber 2| in preparation for the next cycle of operation.

During operation of the cushioning device, there may be a certain amount of leakage past the piston I9 to the upper side thereof, and past the pistons 31, 31a, 38- and 38a into the respective spring chambers associatedtherewith. Since the.

hydraulic. system of the die-cushion a self! contained system, it will? be necessary to return this leakage. fluid into the; operating system to insure that the cylinder chamber 21- is always completely full of liquid at. the end of its upstroke so that the. cushionrplate I81 can act. immediately to support the member 31 when the punch 34 strikes the work-piece 35;- J r e To provide for return of the Ieakage fluid, heretoforementioned, into the operatingsystem, the spring chambers behind the pistons 31 and are are interconnected bymeansof a-passage l'ilprovided in the bolster-plate id, and the spring chambers behind the pistons 3'8 and 380; are interconnected by means of asimilar passage cm. A passage 52 interconnects the spring chambers behind the pistons3lw and 38a, which in turn connects with a passage 53 that connects to a reservoir chamber 54 contained in the boss 55 carried along the side ofthe cylinder-"21. A passage 56 connectsbetween the reservoir chamber 54 and the upper side of'the piston {9 to'permit fluid to pass from above the piston 19' into the reservoir chamber 54, Thereservoir chamber 54 isprovided with a ventopening Hi so that theliquid can drain into the reservoir chamber by gravity. I

T provide for return of liquid from the reservoir chamber 54 tothe cylinderchamber H, a check-valve 53' is provided-between the outlet passage 59 from thereservoir--chamberand-the inlet passage 60 into the cylinder chamber 2!,

The check-valve 58' is normally retained in" a closed position by means of the spring 61' so that during the down-stroke of the piston I!) there will be no loss of fluid from the operating hydraulic system of the die cushion. However, during the upstroke of the piston f9, if there is insuflicient fluid to completely fill the chamber 2| at the end of the upstroke of the piston I9, liquid can be drawn from the reservoir chamber 54 through the check-valve 58 into the cylinder chamber 2! to thereby completelyfill the same and condition the chamber for the next cycle-of operation.

The resistance valve 50, illustrated in Figure 4, will provide a resistance to flow of liquid between the passages 43 and M in either direction of flow. However, if itis desired to obtain an unimpeded flow of liquid into the cylinder chamber ii-during the upstroke of the piston" I9, a resistance valve of the type illustrated in Figure 8 can be used.- In this arrangement a valve member 65 is springpressed to closed position against the valve opening 66 by means of a spring 51, a cage 68 retaining the same in position adjacentthe valve opening 66. The valve member 65 is regulated as to its open position by means of a rod 69 that is operated by suitable means extending exteriorly of the bolster plate 5, such as the knurled knob 49. In this latter instance, however, the stem 45; would carry an eccentric to engage the rod 69 and thus control the opening of the valve member 65 to regulate the resistance between the valve member 65 and the opening 66 when fluid is flowing in an upward direction through the passage 64. However, when fluid is flowing downwardly through the passage 44, and thus downwardly through the opening 66, the valve member 65 can leave the end of the rod 69and compress the spring 61 to provide a full and free opening for passage of fluid through the valve opening 65.

While the apparatus disclosed and described herein constitutes a preferred form of the invention, yet it will be understood that it is capable of mechanical illustration without departing; from: the spiritof thei nvention, and that all modifies tions that wall within the scope of the appended claims areintended to be included herein.

Having thus fully described, my invention, what I claim as new and desire to secure by Letters Patentis:

1'. Incombination, a bolster plate member adapted to rest upon the bed of a forming press support. a forming die, said plate having an opening through the same, a cylinder chamber secured to the underside of said plate and beneath said opening and having a piston reciprocable therein, means carried by said piston and extending" therefrom supporting a plate on the end thereof positioned within said opening that is. reciprocable therein, a chamber in said bolster plate, means in said bolster plate chamber for effecting a change in the effective volume thereof for securing fluid therein, and a passage connecting said cylinder chamber with said bolster plate chamber to permit displacement of fluid therebetweenupon reciprocation of said piston.

2. In combination, a bolster plate member adapted to rest upon the bed of a forming press and support a forming die, said plate having an opening through the same, a cylinder chamber secured to the underside'of said plate and beneath said opening and having a piston reciprocable therein, means carried by said piston and extending therefrom supporting a plate on the end thereof positioned within said opening that is reciprocable therein, a chamber in said bolster plate, movable means in said bolster plate chamber for efi'ecti'ng a change in the effective volume of said chamber means for receiving fluid therein, means in said bolster plate chamber to resist the movement of said movable means until a determined pressure is built up in said chamber, and a passage connecting said bolster plate chamber with said cylinder chamber through which fluid is transferred from said cylinder chamber to said bolster plate chamber under pressure as caused by said resistance means during movement of said piston in one direction thereof.

3. In combination, a bolster plate member adapted to be positioned upon the bed of a formingpress and support a die and having an opening therethrough, a hydraulic cushioning cylinder positioned on one side of said plate in substantial alignment'with said opening and having a piston therein supporting a cushioning plate in said opening, a chamber in said bolster plate having pressure resistance means therein for effecting a change in the efiective volume of the chamber means when pressure is built up in the'chamber means by liquid being transferred thereto, and passage'means in said bolster'plate and said cushioning cylinder hydraulically interc'onnectingsaid cushioning cylinder'with said bolster platechamber to permit an interchange of liquid under pressure th'erebetween upon a change 7 in volume in the cushioning cylinder caused by reciprocable movement of the piston therein. I

4. In combination, a bolster plate member adapted to be positioned upon the bed of a forming press and support a die'and having an opening therethrough, ahydraulic cushioning cylinder positioned on one side of said plate in substantial alignment with said opening and having a piston therein supporting a cushioning plate in said opening, a chamber in said bolster plate having pressure resistance. means therein for effecting a change in the efiective volume of the chamber means when pressure is built up in the chamber means by liquid being transferred thereto, passage means in said bolster plate and said cushioning cylinder hydraulically interconnecting said cushioning cylinder with said bolster plate chamber to permit an interchange of liquid under pressure therebetween upon a change in volume in the cushioning cylinder caused by reciproc-able movement of the piston therein, and resistance valve means in said passage means for resisting the movement of liquid from said cushioning cylinder to said bolster plate chamber means.

5. In combination, a bolster plate member adapted to be positioned upon the bed of a forming press and support a die and having an opening therethrough, a hydraulic cushioning cylinder positioned on one side of said plate in substantial alignment with said opening and having a piston therein supporting a cushioning plate in said opening, a chamber in said bolster plate, piston means reciprocable in said bolster plate chamber and opposed in movement thereof in one direction by spring means contained in the said chamber, a passage in said bolster plate and said cushioning cylinder hydraulically connecting said cushioning cylinder with said bolster plate chamber whereby liquid can be transmitted from said cushioning cylinder into. said bolster plate chamber to move said second piston means against said spring means and thereby develop hydraulic pressure in said cushioning cylinder to resist movement of the piston therein, and resistance valve means in said passage for resisting the flow of liquid from the cushioning cylinder to the chamber means to increase the pressure in the cushioning cylinder as determined by the pressure drop across the resistance valve means.

.6. In combination, a bolster plate member adapted to be positioned upon the bed of a forming press and support a die and having an opening therethrough, a hydraulic cushioning cylinder positioned on one side of said plate in substantial alignment with said opening and having a piston, therein supporting a cushioning plate in said opening, a chamber in said bolster plate, piston means reciprocable in said bolster plate chamber and opposed in movement thereof in one direction by spring means, a passage in said bolster plate and said cushioning cylinder hydraulically connecting said cushioning cylinder with said bolster plate chamber whereby liquid can be transmitted from said cushioning cylinder into the said chamber to move said piston means against said spring means and thereby develop hydraulic pressure in said cushioning cylinder to resist movement of the piston therein, a passage for conducting hydraulic liquid that leaks past either of said piston means to a reservoir on said bolster plate, and a passage including a check valve therein connecting said reservoir with said cushioning cylinder to permit hydraulic liquid to flow from said reservoir to said cushionin cylinder periodically to refill the cushioning cylinder during reciprocation thereof of any liquid lost therefrom. I 7. In combination, a bolster plate member adapted to be positioned upon the bed of a forming press and support a die and having an opening therethrough, a hydraulic cushioning cylinder positioned on one side of said plate in substantial alignment with said opening and having a piston therein supporting a cushioning plate in said opening for reciprocation therein, a chamber extending transversely through said bolster plate substantially paralleled with the upper surface thereof Ior receiving liquid from said hydraulic cushioning cylinder, piston means in said chamber, spring means in said chamber engaged by said piston means to oppose movement of said piston means in one direction, a passage in said bolster plate and said cushioning ylinder hydraulically connecting said cushioning cylinder with said bolster plate chamber whereby liquid can be transmitted from said cushioning cylinder into the said chamber to move said piston means against said spring and thereby develop hydraulic pressure against said cushioning cylinder to resist movement of the piston in the cushioning cylinder, a reservoir on said bolster plate for hydraulic liquid, and passage means connecting said reservoir with said cushioning cylinder whereby to supply said cylinder with liquid from said reservoir to refill the same during reciprocation of said piston in said cushioning cylinder.

8. In combination, a bolster plate member adapted to be positioned upon the bed of a forming press and support a die and having an opening therethrough, a hydraulic cushioning cylinder positioned on one side of said plate in substantial alignment with said opening and having a piston therein supporting a cushioning plate in said opening for reciprocation therein, bores extending transversely through said bolster plate adjacent each side of the opening therein and substantially parallel to the upper surface of the bolster plate, a piston in each of said bores reciprocable therein for regulating the effective volume thereof to receive liquid from said hydraulic cushioning cylinder, spring means in each of said bores against which said pistons in the respective bores are urged, a passage hydraulically interconnecting said bores positioned in said bolster plate and said hydraulic cushioning cylinder whereby liquid can be transmitted from said hydraulic cushioning cylinder into said bores to move said pistons against the. springs therein and thereby develop hydraulic pressure in said cushioning cylinder to resist movement of the piston in the cushioning cylinder, a liquid reservoir in said cushioning cylinder, and a passage including a check valve therein hydraulically connecting said reservoir with said cushioning cylinder to permit hydraulic liquid to flow from the reservoir to said cushioning cylinder to refill the same during the reciprocation thereof of any lost liquid.

9. In combination, a bolster plate member adapted to be positioned upon the bed of a forming press and support a die and having an opening therethrough, a hydraulic cushioning cylinder positioned on one side of said plate in substantial alignment with said opening and having a piston therein supporting a cushioning plate in said opening for reciprocation therein, bores extending transversely through said bolster plate adjacent each side of the opening therein and substantially paralleled to the upper surface of the bolster plate, a piston in each of said bores reciprocable therein for regulating the effective volume thereof to receive liquid from said hydraulic cushioning cylinder, spring means in each of said bores against which said pistons in the respective bores are urged, a passage hydraulically interconnecting said bores positioned in said bolster plate and said hydraulic cushioning cylinder whereby liquid can be transmitted from said hydraulic cushioning cylinder into said bores to move said pistons against the springs therein and REFERENCES CITED thereby develop hydraulic pressure in said cushioning cylinder to resist movement of the piston The following references are of record i the in the cushioning cylinder, at liquid reservoir in file this P e Said cushioning cylinder, and a passage hydralu- 5 UNITED STATES P ATENTS lically connectmg said bores and said cushioning cylinder with said reservoir for conducting to said Number Date reservoir hydraulic liquid that leaks past either 1,647,045 Humphlls 06th 1927 the pistons in said bores or the piston in said 1,664,435 Rode 3, 1923 hydraulic cushioning cylinder. 10 1,774,614 Rode Sept- 1930 1,846,439 Rode et a1. Feb. 23, 1932 HOWARD AIDREDGE. 1.982.471 GIUSS w. NOV. 27, 1934

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