US2905032A

US2905032A - Die forging presses

Info

Publication number: US2905032A
Application number: US585879A
Authority: US
Inventors: Samuel J Fuchs
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-05-18
Filing date: 1956-05-18
Publication date: 1959-09-22
Anticipated expiration: 1976-09-22

Description

Sept. 22, 1959 I s FUHS 2,905,032

DIE FORGING PRESSES Filed May 18, 1956 2 Sheets-Sheat l 26 'Er a //IIIIIlII/l'I IIIIIIIIIIIl/I//jfl IN KEN TOR.

Sept.22, 1959 I sime@ 2,9o5,o32 I DIE FORGING PRESSQES Sheets-Sheet 2 rap..."

'III/l United States Patent O DIE FORGING PRESSES Samuel J. Fuchs, New York, N.Y. Application May 18, 1956, Serial No. '585,879 -3 Claims. (CI. 78-44) This invention relates to die forging presses, especially heavy presses, and a method of Operating them.

The die parts usually called die blocks, which are the members in direct contact with the work being formed or forged, and the die sets, one of which is inserted between each die block and a platen of the press, are usually fa'brica-ted of high strength alloy steel. On the other hand the platens and their supporting beams, because of their large eXtent, are usually made of ordinary structural steel for economic reasons. 'Ihe die sets are pris-. matic blocks which transmt the force applied by the platens to the die.

To make the die sets thick enough so that when they are under load by the action of the press, they do not subject the die blocks or platens, especially the latter, to unequal stress distribution would be uneconomical because of the high cost of high strength alloy steel.

The use of relatively thin die sets tends to result in excessive concentration of stress on theplatens with consequen-t ndentation and permanent set of their surface where it contacts the die sets.

It is an object of the present invention to make such provision that the economy of using thin die sets can be eftected. It is proposed to accomplish this by providing mating surfaces, between the die set and the platen, so formed relatively to each other' as to eliminate or equalize substantially the unequal stress noted above. There are a number of ways in which this can be done. For example, the. mating. surface of the die set can be suitablyconcaved toward thevplaten, the mating surface of the platen can be suitably concaved toward the die set, or the relative configurations of said mating surfaces can be such as to provide a suitable cavity. In its broadest sense suitable .space is to -be provided which tends to close up to reduce or eliminate unequal distribution'of stress .upon the platen when the pressure is applied by the press. q

An object of the invention is the mitigation of the accentuated stresses prevailingjin present construction in proximity to the central portion of the die set-platen interface.

My preferred way is to use :an insert or lamination with a concave surface between the die set and platen, keeping the surfaces of the die set and platen plane because of shop difiiculties in handling such cumbersome pieces as die sets and platens. Said concave surface preferably forms a depression or cavity which is greatest at its central portion, tapering of to zero at its periphery.

Other objects 'and advantages will become apparent -upon further study of the specification and drawings, in which:

Fig. 1 is a conventionalized or diagrammatic end View of the working parts of a typical heavy capacity die forging press except that it shows inserts or laminations provided between the die sets and platens in accordance with the preferred form of my invention.

2,905,032 Pa'tented Sept. 22, 1959 Fig. 2 is a section of the press taken along the line 2--2 of Fig. 1 'but with the foundation omitted and the two center rods broken ofi for clarity.

Fig. 3 is an enlarged partial elevation of the press of Fig. 1 showing only the lower die block, die set, insert and a broken away portion of the platen before the pressure is applied by the press.

Fig. 4 is an enlarged partial section, along the line.

4-4 of Fig. 3, through the lower die set, insert and platen before the pressure is applied by the press. The insert or lamination is concave toward the bottom.

Fig. 5 is a similar section to that of Fig. 4 but shows conditions after the load `or pressure has been applied, the die set having become convex downward at its lower surface.

Fig. 6 is a diagram showing the various pressures under consideration.

-Fig. 7 is a partial section taken similarly to Fig. 4 but with a modified insert, the modification of the insert consistng in providing it with `a concavity or depression both in its top and in its bottom.

Fig. 8 is a partial section taken similarly to Fig. 4 but modified by the provision of two inserts with suitable cavities.

Fig. 9 is a partial section taken similarly to Fig. 4

- but without the provision of an insert, the concavity being provided on the bottom of the die set itself, and

Fig. 10 is a partial section taken similarly to Fig. 4 but without the provision of an insert, the cavity being provided in the platen.

Referring to Figs. 1 and 2, which show the preferred form of my invention embodied in `a die forging press,

q the die blocks 10 and 11 `are supported `as in the usual practice by die

sets

12 and 13. Die

sets

12 and 13 are essentially prismatic blocks of high strength alloy steel, which transmit the pressure developed by the press upon die blocks 10 and 11 through upper and lower inscrts or

laminations

14 and 15 to the upper and

lower platens

16 and 17 respectively.

Upper cross beams 18 are in operative relationto upper platen 16. Lower cross beams 19 are in operative relation to lower platen 17 and support the press by resting on foundation 20. Cross beams 19 are stationary, while upper cross beams 18 and additional or lowermost cross beams 22 are movable. There is a cross bearn 22 i in Vertical :alignment with each pair of

cross beams

18 and 19. Each upper cross beam 18 has a tie rod 23 eX-tending between it and a lowermost cross beam 22. Said tie rods are slida-bly mounted in beams 19. EX- tending between each p a-ir of

cross beams

19 and 22 are hydraulic cylinders 24.' As is well known in the art when cylinders 24 force down their pisten rods or rams 25,`upper die block 10 is forced down to lower die block 1 1 compressing whatever work that may have been set between said blocks.

When die set 13 is subjected to pressure, Fig. 6, where the die set 13 is shown in mating contact with a plane surface, because of the flexibility of said die set and die block 11, the line of pressure is that shown by curve BAB, the pressure being greatest near A. This would result for usual die set proportions in producing heavier pressure toward the center of any work being forged in die block 11 and subject the platen 17 to a greater intensity of pressure locally. However, if a cavity BDBCB were provided, the excess pressure in the vicinity of A would be relieved by the deflection of die set 13 but the pressure would be ncreased toward regions B. If the proper form of cavity were provided, the pressure would be uniform as shown by line FGF. It is an object of the invention to produce such uniform pressure.

In the foregoing description of the development of stress distribution according to the invention, the assumpton was made of a concentrically uniform intensity of load delivered to the die set from the die block. This is the industrially important ca e o responding s stantially to the majority of industrial applications. Where, however, the appled load is cc emri at is, t S shifted to one side With respect to he a s Of t e die set, .the function and Co structi n f th pa ts to provide a cavity or cavites is the same as described herein except that the preformed hollowed .out ,surface or Surfaces is asymmetrically modified, the cen ra p rtion f the cavity or cavites being correspondingly shifted to one side with respect to the die .set.

As noted before, the cavty or cavitie can he provided in a number of diiferent ways, Refrring to Figs. 3, 4 and 5. insert 15 -s shown located bet een ie set ,13 and laten 17. Insert 15 is concave on the bottom. In Figs. 3 and 4 no pressure has been applied by the press so that the cavity 26 is visible. The bottom of die set 13 is plane. Upon the :application of 1111655111?, avity 26 disappears, Fig, 5, the lower surface of die set 13 becoming substantally convex downward.

In Fig. 7 an insert 27 is shown located between die set 13 and platen 17. Insert 27 is provided 'With a ca ity 28 in its uppcr surface and a cavity 29 in its lower ,surface, These two avities together function :in a similar manrer to the single cavity 26 of Fig. 3.

In Fg, 8 an pp insert 30 is p ovided with a cav y 31 in its lower surface and a lower insert 32 is pro i ed with a cavity 33 in its lower .surface. These cavities together are the equivalent of the single cavity 26 of Fig. 3.

In Fig. 9, die set 13 is provided with ,a cavity 34 :which closes p When p ssure is appled resul ng n equal distribution of stress.

In Fig. 10, platen `17 is provided With a avity 35 which clo p when pressure is app ied resulting in equal distribution of stress.

The cavities noted above may be supplid either for the upper assembly of the press with its platen 16, die block and die set 12 or for the lower assernbly with its platen 17, die block `11 and die set 13 or the cavities may be applied for both the upper and lower assemblies of the press.

With all the various forms of inserts or laminations such as inserts or laminations 14, '15, 27, .30 and 32, there exists the common feature of an equivalent aggregate thickness of hollow space included between die set and platen in the unloaded condition, which is elastically closeable under load. As noted before, the mating surfaces between die set and platen can also be preformed to achieve the 'same result of hollow included space, but the accurate preparation of the surfaces of these massive members into the required contour would be cumbersome and inconvenient.

The depth of the hollow space or oavity diminishes generally from that at the central portion, distance DC Fg. 6, to the perimeter of the cavity. Said depth is of an amount calculated to result in the desired stress distribution or equalization of stress under load at the mating surfaces of the die set and the platen. The numerical data required for the determnation of the depth at each coordinate point of the hollow space or cavity may be obtained in advance by calculation but preferably by :a series of tcsts with scale models of gypsum, glass, or other elastic materials. From the numerc l a a so o'btained, the required contoured surface can be fabricated by those sklled in the art.

I claim:

1. Lamination means adapted to be set intermediate of the die block and the platen of a press, said means being of varied thickness, being thnner at its central portion than toward its edges to allow the die block to deect elastically more at the central portion than towards the edges when pressure is applicd to it by the press, so as to result in substantal equalizaton of pressure on the platen.

2, In a press, a Construction provided intermediate of the die set and the platen of the press, said Construction aving mating surfaces formed to provide space between them, said space being deeper at some portions than at others to allow the .die set, when pressure is applied to it y the press, to deflect elastcally more at the deeper portions than at others, so as to effect equalzation of pressure on the platen, said space being provided by the relative form of the mating surfaces of the platen and the ie set, the mating surface of the platen being substantially fiat .and that of the die set concaved.

3 Ina press, a Construction provided intermediate of he ie .and the platen of the press, said Construction having mating surfaces formed to provide space between hem, said space being deeper at some portions than at others to allow the die set when pressure 's applied to it by the press, to defiect elastcally more at the deeper portions than at others, so as to etfect equalization of preure on the platen, said 'space 'being provided by the relative form of the mating surfaces of the platen and the die set, the mating surface of the die set being substantially flat and that of the platen concaved.

References Cited in the file of this patent UNITED STATES PATENTS 87,304 Smith Feb. 23, 1869 1,206656 Benedictus Nov. 28, 1916 l246,'740 Haefely Nov. 13, 1917 1,352911 Paque ..-1- Sept. 14, 1920 1,582,571 Budd Apr. 27, 1926 1,695,239 Norton Dec. 11, 1928 1, 778,43 8 Vincent Oct. 14, 1930 2,710,903 Seelofi? et al. June 14, 1955 FOREIGN PATENTS 16,200 Great Britain Dec. 15, 1904