US3080778A

US3080778A - Ram construction

Info

Publication number: US3080778A
Application number: US824509A
Authority: US
Inventors: Jr Robert L Alcorn
Original assignee: Chambersburg Engineering Co
Current assignee: Chambersburg Engineering Co
Priority date: 1959-07-02
Filing date: 1959-07-02
Publication date: 1963-03-12
Anticipated expiration: 1980-03-12

Description

March 12, 1963 R L. ALCORN, JR

RAM CONSTRUCTION Filed July 2, 1959 INVENTOR: ROBERT L. ALCORN ,JR.

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United States Patent Q 3,080,778 RAM CGNSTRUgyTIONP or to b t L. Alcorn, Jr., Chambers mg, a., assign Cli mbersburg Engineering lCompany, Chamhershurg,

Pa. acor oration of Pennsy Vania F iledJuly 2, 1959, Ser. No. seassa 5 (Ilaims. ((31.78-43) invention relates to a ram construction for an img: forging machine, and the like. Although it has been developed for machines in which a pair of rams are horizontally disposed and arranged to oppose one another, it may be employed to advantage on vertical drop hammers and other devices. More specifically, the present invention concerns a ram construction which 18 a inulti-piece structure including a shock-absorb ng cou w it. i fi l: prior art, rams for impact machines have been extremely expensive. Such rams, for the most part, have been constructed of one piece or of multiple SOlld pieces designed to absorb any shock atumpact. It has been known that much of the energy in such a machine is dissipated because the opposed rams of the same mass travel at the same speed in opposite directions and hence upon impact the equal and opposite energies developed tend to be effectively cancelled out. A certain amount of energy maybe transformed to heat and other energy may produce vibration or reverberation. The forces 1nvolved upon impact, however, are sufficiently great that there has apparently been considerable reluctance to adopt ram structures of lighter than conventional construction. I

The present invention is directed to a ram of considerably lighter construction than is common m the prior art and of a form which permits the use of stoc k materials. More specifically, the present invention involves the use of a shock mount or cushioning element composed preferably of resilient low hysteresis material of a relatively high durometer measurement The use of such a coupling member enables construct on of the support for the ram from relatively light materials, such as aluminum. For example in a preferred form, rather than a solid structure, a rather light weight support structure made from two relatively thin walled tubes suffic1ently rigid to support the weight of the ram head may be used. More specifically, the present invention m 1ts broadest form relates to an impact machine ram m which three principal components are employed The first or these is a ram supporting structure including a supporting column and a piston. The structure may be made of any suitable material but, in accordance with the present invention, for the first time may be made of extremely light tubular materials of stock sizes and relatively simple light weight cast parts. The second element of the combination is a ram head of strong, tough material. The ram head characteristically may be composed of a cast steel alloy or other materials sufficiently hard to accept the impact forces transmitted from the actual forging tools or dies which they support. Finally, between the ram head and the supporting structure is a coupling or connecting member of resilient material which is adapted to mechanically connect the ram head to the supporting column in such a way that the forces between the ram and the column acting upon the connecting member are shear forces. The connecting member is provided with physical properties which enable absorption of most of the forces involved. Thus, despite the fact that it is of resilient nature, it is extremely hard, and it is preferably of low hysteresis properties so that it can be distorted and return promptly to its original condition without the gen eration of-excessive heat. i

The ram head alone may be of a novel construction. In a"particular embodiment, it has a hollow in its supported end into which the supporting column is introduced and within whichthe coupling member is arranged with-' in an annular groove which extends radially outwardly from within the hollow. T

For abetter understanding of the present invention, reference is made to the accompanying drawings wherein FIG. 1 illustrates schematically in elevation a typical machine in which the ram of the present invention is em ployed; I 3 FIG. 2 is a sectional view taken along line 2-2 of FIG. 1 showing the construction of the ram; and v F1633 is 'a sectional view taken along line 3-3 of FIG.2.

A common and important type of impact forging machine is the doubleiram'impacter shown in FIG. 1. This machine has a base, generally designated 10, of relatively elongated form supportingcylinders 11 and 12 at opposite ends positioned to support two ram structures 13 and 14'. The rams in thistype of machine are horizontally disposed and arranged to oppose one another, as shown. Each of the rams 13, 14 has its own supporting column 15, 16 on one end of which is a piston head 17, 18 which is snugly engaged within the cylin der 11, 12, respectively. At their opposite ends, the rams have ram heads 19, 20 which carry forging dies 21, 22 which are designed to actually impact and form the material to be forged. The dies may be held in place by virtue of

dovetail appendages

23, 24 which are engaged in solts 25, 26 of similar fornr and depth but greater width than the

appendages

23, 24. The dies are wedged in place by means of pieces 27, 2S betweenthe side walls of the grooves-and the dovetail appendages to hold the die pieces in place. Additional 'supportand guide means 30, 31 guide the ram'heads and provide increased stability. Sensing elements for various controls may also be located in this region.

Referring to FIG. 3, it will be seen that the ram head 19 is provided with flanges 19a and 1% extending laterally toward the bottom of the head. The support structure is grooved at 30a and 30b to' accomodate the flanges 19a and 19b and between the flanges 19a and 1591; are imposed suitable bearing inserts 31a and 31b. i

In operation, the rams are fluid operated by providing a greater hydraulic force behind the piston heads 1'7, v18 within the cylinders 11, 12 than in front of the piston heads. To withdraw the pistons, a greater force is provided on the front side of the piston than on the back. The specific controls are beyond the scope of this application but examples of suitable controls may be found in the United States Patents Nos. 2,729,943 and'2,785,535.

The specific ram construction of ram 13 may be seen in FIG. 2. Great variety is possible in the actual form of the ram construction, but FIG. 2 illustrates a preferred form. In this particular construction, the ram head 19 is provided with a hollow 35 adjacent and extending inwardly from the back side thereof. This hollow or recess may be varied considerably, depending upon the type of construction employed. In the form shown, withinthe recess there is provided an annular groove 36 which has generally parallel side walls 37 and 38. The groove 36 is preferably of uniform diameter and preferably of same or smaller diameter than the mouth 39 of the hollow. The hollow from the mouth tapers inwardly in a surface 40 which extends to the radially extending wall 37.

The inwardly tapering surface 40 enables the resilient ring 41, shown snugly accommodated within the annular groove 36, to be pressed through the opening into the groove. The ring 41 is preferably rectangular in cross section, as shown, and is designed to extend radially inwardly well beyond the deeper side wall 38 into the pass.

hollow. The material selected for the ring is preferably rubber or some appropriate elastic or resilient material of relatively high durometer measurement so as to be difficult to deform. The material must have a high shear strength. It preferably has low hysteresis effect so that upon deformation the ring tends to return promptly to its original shape and so that it generates very little heat energy in the process.

In the course of assembly, the recessed plate 42 which makes contact with one end of the ring beyond wall 38 is first inserted within the hollow 35 which is further recessed beyond Wall 38 so that plate 42 is out of the way of ring 41 when it is inserted in the groove. Once ring 41 is inserted, a snugly fitting inner tube 43 of steel or other suitable material, intended to minimize the amount of compression effect upon ring 41, may be inserted within ring 41. Thereafter plate 44 may be put in place and bolts 45 employed to .pull the plates 42 and 44 together so that they snugly bracket the ends of the ring 41 adjacent its inner edge. With this arrangement, it will be seen that forces applied by the ram, and specifically by shoulder 38, will tend to produce a shearing force in the ring 41 between plate 44 and shoulder 38. Plate 44 is provided with rounded edges 44a which tend to supply greater area and a larger diameter the greater the shear efiect applied to ring 41. Ring 43 is left against plate 44 and is preferably barely longer than ring 41 so that any movement by it may be accommodated by the recess 42a in plate 42. The bolts 45 are preferably threaded only into plate 42 and pass slidably through unthreaded holes in plate 44.

Plate 44 is preferably also provided with a large threaded hole 47 at its center which engages threads 48a on inner tubular member 48 of the supporting column 13. .Tubular member 48 is preferably stock material of some conventional aluminum alloy and of conventional size. The other end of tube 48 is similarly threaded with threads 48b which are engaged by threads on cap member 49. Cap member 49 has a flange 49a providing threaded holes through which spaced threaded bolts 50 The ends of bolts 50 engage shoulder 51a on an annular flange 51 which snugly accommodates a tubular portion 49b of cap 49.

Flange 51 is part of an integral hollow cast assembly 52 providing the piston head 17. Although hollow, casting 52 is ribbed with radially extending ribs 52:: for greater strength and force transmitting capacity. Casting 52 is provided with an outer diameter suitable for engagement within cylinder 11 and may be made of an aluminum alloy casting.

Completing the assembly is an outer tubular member 53 of aluminum alloy, and preferably of a stock size which extends between shoulders on casting 52 and plate 44, respectively, which shoulders prevent lateral displacement.

The assembly is completed after bolts 45 have been put in place by threading the tubular member 48 into plate 44, placing the tubular member 53 and then the casting 52 in place, threading the cap 49 onto the end of tubular member 48 and tightening the bolts 50. As the bolts 50 are tightened, the tube 48 is placed in tension and the tube 53 is placed in compression. The forces involved can be adjusted to an optimum.

'In operation, upon impact of the dies supported by the rams, each ram head ceases to move forward. Ram head 19, for example, stops but inertia carries the plate 44 and the ram head supporting structure forward thereby imposing a shearing force on ring 41. By providing a ring of sutficiently hard durometer reading and of low hysteresis, all energy may be absorbed without producing an undue amount of heat. The support structure, therefore, may be made of the light construction illustrated.

Many modifications may be made in accordance with the present invention. For example, the ramhead might be provided with a shank instead of a hollow and the ring extend outwardly from ,the ram head to means on the support peripherally engaging the structure. Alternatively, instead of making the resilient member a ring as shown in the structure specifically described without greatly modifying the structure, a solid rubber plate might be interposed These and many other modifications within the scope of the claims may be undertaken. All such modifications within the scope of the claims are intended to be within the scope and spirit of the present invention. Moreover, no limitation is intended on the type of machine in which the ram of the present invention is embodied, the ram being useful in a wide variety of impacters.

I claim:

1. A ram for an impact machine comprising a ram supporting structure including a supporting column, a

j ram head of strong, tough material and a resilient ring providing the sole coupling member between the column and the ram head and having physical properties enabling the absorption by a shearing effect of most of the forces developed upon the impact of the ram head, said ring being received in opposed annular grooves each defined by side and bottom walls in said column and ram head, respectively, to provide confining rigid boundary walls around most of the ring, one of the side walls of each of said grooves providing opposed shoulders opposing axial impact movement of the ram head with respect to the column, the outer radius of one of said opposed shoulders being greater than the inner radius of the other of said opposed shoulders.

2. The ram of claim 1 in which the ram head is hollow and its shoulder is radially inwardly extending and the column extends into the hollow of the ram head and has its shoulder outwardly extending.

3. The ram of claim 2 in which the sole coupling member is a ring of rectangular cross section having low hysteresis properties.

4. The ram of claim 1 in which the column is composed of metal tubing.

5. A ram for an impact machine comprising a ram supporting structure including a tubular supporting column, an end plate terminating said column and providing thereon a circumferential shoulder, a ram head of strong, tough material having a recess in one end thereof defined by an inwardly directed annular wall, an annular groove formed in said annular wall and including axially spaced radially extending and parallel inner and outer side walls, said inner side wall providing a radially extending circumferential shoulder, the inner radius of which is less than the radius of said circumferential shoulder provided on said end plate, a ring of low hysteresis rubber snugly fitting within said groove and having an inwardly extending annular portion projecting into said recess, means clamping said inwardly extending annular portion of said ring against the circumferential shoulder provided on the column, said ring thereby providing the sole coupling means between said tubular column and said ram head, rigid means for preventing radially inward movement of said ring, said clamping means and said rigid means holding confined the inwardly extending annular portion of the ring, whereby, upon impact imposed upon said ram head, axial forces acting between said ram head and said column move said column inwardly within said recess and References Cited in the file of this patent UNITED STATES PATENTS St. Lawrence Mar. 13, 1888 1,450,177 Houpert Apr. 3, 1923 1,812,464 Billings June 30, 1931 (Other references on following page) 5 UNITED STATES PATENTS Flintermann Dec. 1, 1931 Schneider Sept. 6, 1932 McGuy Mar. 5, 1935 Fitzgerald Apr. 2, 1940 5 6 Knudsen Sept. 17, 1940' Thiry Dec. 2, 1947 FOREIGN PATENTS Germany NOV. 25, 1939

Claims

1. A RAM FOR AN IMPACT MACHINE COMPRISING A RAM SUPPORTING STRUCTURE INCLUDING A SUPPORTING COLUMN, A RAM HEAD OF STRONG, TOUGH MATERIAL AND A RESILIENT RING PROVIDING THE SOLE COUPLING MEMBER BETWEEN THE COLUMN AND THE RAM HEAD AND HAVING PHYSICAL PROPERTIES ENABLING THE ABSORPTION BY A SHEARING EFFECT OF MOST OF THE FORCES DEVELOPED UPON THE IMPACT OF THE RAM HEAD, SAID RING BEING RECEIVED IN OPPOSED ANNULAR GROOVES EACH DEFINED BY SIDE AND BOTTOM WALLS IN SAID COLUMN AND RAM HEAD, RESPECTIVELY, TO PROVIDE CONFINING RIGID BOUNDARY WALLS AROUND MOST OF THE RING, ONE OF THE SIDE WALLS OF EACH OF SAID GROOVES PROVIDING OPPOSED SHOULDERS OPPOSING AXIAL IMPACT MOVEMENT OF THE RAM HEAD WITH RESPECT TO THE COLUMN, THE OUTER RADIUS OF ONE OF SAID OPPOSED SHOULDERS BEING GREATER THAN THE INNER RADIUS OF THE OTHER OF SAID OPPOSED SHOULDERS.