US3450035A - Hydraulic press - Google Patents

Description

June 17, 1969 E. CHAPMAN HYDRAULIC PRESS Filed April 10. 1967 United States Patent 3,450,035 HYDRAULIC PRESS Everett Chapman, P.O. Box 207, West Chester, Pa. 19380 Filed Apr. 10, 1967, Ser. No. 629,670 Int. Cl. B3011 1/00, 1/32 U.S. Cl. 100-214 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to hydraulic presses and in particular relates to improvements in loop-shaped presses of the kind shown in my Patent 2,174,550.

The principal object of the invention is to provide improved structure for presses, which improvements greatly extend the operating capacity of the press: for example, up to 10,000 tons.

In one aspect the invention provides in loop-type presses a medium interposed between each semi-circular end sec tion and its complementary load pad, which operates to cause the whole surface area of the pad and of the end section to participate in transferring load as between the pad and the end section. This provides for maximum bearing area.

Providing for the whole of the surface area of the pad and the whole of the surface area of the end section to participate or do work in the transfer of load between the pad and the end section has several highly desirable and important advantages.

One of the principal advantages is that the transfer of load between the bearing of surface areas of the pad and end section is not accomplished through the medium of several small localized contact points. High stress concentration is avoided. Pressures are distributed over the whole bearing or surface area, and as a consequence the work level of the press is raised.

The medium between the pad and the end section provides for maximum stress distribution without the necessity of machining the bearing surfaces and without depending upon cold flow of engaging points on the bearing surface to establish the actual bearing areas. This eliminates expensive and time-consuming operations which would be necessary for accurately matching the bearing surfaces and makes the bearing areas independent of load.

In another aspect the invention contemplates improved loading structure comprising a hydraulic cylinder supporting the platen piston and mounted on a relatively massive load pad connected to the opposite end of the press. The cylinder is free from the connecting means so that it does not participate in the transfer of load reactions between the ends of the press and does work only to contain the hydraulic fluid.

The cylinder load pad arrangement is exceedingly important in that it provides a practical means for the construction of presses of extremely large capacities.

The load transfer medium and the loading structure cooperate in obtaining the objective of extending the operating capacity of the press.

A preferred form of the invention will be described below in connection with the following drawings, wherein:

FIGURE 1 is a front elevational view of a loop-shaped press incorporating the invention;

FIGURE 2 is a side elevational FIGURE 1.

The frame 1 of the press comprises a continuous loop of cold rolled steel and includes the annular end sections 2 and 3, which are interconnected by the center sections 4 and 5.

The frame 1 is fabricated by bending the steel into identical half sections which are joined together by welding in the areas 6 and 7.

Adjacent the end section 2 is a load pad 10, and adjacent the end section 3 is a load pad 11. The top load pad 10 is held fixed with respect to the end section by the bracket means 12 and 13.

In fabricating the frame 1, no machine operation is performed on the end or center sections. Thus the inner surface 14 of the end 2 and the inner surface 15 of the end 3 are in the same physical condition as rolled except for conventional cleaning. This non-machined condition is especially advantageous in reducing fabrication costs.

The load pads are preferably cast or forged members which are also left in the non-machined condition. The outer non-machined surface 16 of the pad 10 is in juxtaposition with the non-machined surface 14. The same condition prevails for the surface 15 and the surface 17 on the pad 11.

The surfaces 14, 15, 16, and 17 are load transfer surfaces as between the respective pads and the end sections. Between the surfaces 14 and 16 is a load transfer medium 20. and between the surfaces 15 and 17 is a load transfer medium 21. These transfer mediums provide that the whole area of the transfer surfaces participate in the load transfer function. As will be apparent to those skilled in the art, this condition is especially advantageous in that it eliminates for all practical purposes undesired stress concentrations and thereby permits the physical size of components to be minimized and raises the Work level of the press.

The invention contemplates that the transfer mediums 20 and 21 comprise particles of a compression resistant filler material fixed in position between the load transfer surfaces by a hardened resin. The amount and uniform dispersement of the filler and the holding of the same by the resin provides that the filler material does substantially all of the work in transferring loads or compression forces between the end pad and the end section.

The resin and the suspended filler engage the minute interstices of the surface and permit the whole surface to participate in the load transfer function. The resin and the filler are poured between the pad and the end sections and then hardened in place. Conventional jigs to hold the pad and end section along with conventional seals to dam the resin are used. Hardening is effected at room or at an elevated temperature.

A preferred resin is Shell Oil No. 928 or Ren Plastic No. 1101. For a hardener with the foregoing resin, I prefer to use a mixture by volume of 55% resin and 45% hardener. As will be understood, the stiffness or modulus of the mixture can be varied by changing the ratio of resin to hardener.

For a filler material, limestone in talc-like form is superior, and with a resin h ardener mixture as above mentioncd, the quantity of filler is approximately 65% by weight of pure resin. The filler is substantially uniformly dispersed throughout the resin-hardener mixture.

The press loading means described herein is particularly advantageous in that it provides a practical relatively inexpensive means for the fabrication of presses of capacities approaching 10,000 tons.

The cylinder 22 is supported on the planar surface 23 of the load pad 11 and extends upwardly toward the view of the press of Work table 24 on the load pad 10. The cylinder is secured to the load pad by conventional hold down brackets not shown.

The cylinder 22 carries the piston 28 having work platen 26. The piston is adapted to be recipnocated along the cylinder axis by fluid pressure in the chamber 27. The means for supplying the chamber 27 is conventional.

Preferably the end of the cylinder 22 is closed by a fluid seal arrangement which comprises a disk 30 and an O-ring 31 or the like in the space between the periphery of the disk and the inner wall of the cylinder.

As will be observed, the cylinder 22 is connected with the center sections 4 and 5 only by virtue of being mounted on the load pad. The cylinder does not participate in the transfer of load as between the ends of the press. Thus, the cylinder needs only be of a physical size and strength to maintain the fluid within the chamber 27 and therefore can be minimized in size.

A cylinder supported on a load pad comprises a structure which is easy to fabricate by conventional methods in sizes of relatively massive proportions. The machining of the inside of the cylinder in large sizes can be accomplished with standard size shop tools and equipment.

I claim:

1. In a press structure:

a frame formed by an elongated continuous loop of rolled steel comprising a pair of annular end sections interconnected by center sections, the inner surface of each end section being non-machined;

a load pad in each said end section, each load pad including an outer, non-machined surface facing the inner, non-machined surface of its end section, the two surfaces being spaced apart from one another; and

in each space between said non-machined surfaces, a mass occupying the space and comprising a plurality f particles of filler material fixed in position by a hardened resin filling the space between the particles and the mass being characterized: (a) by that it is the hardened product of a mixture comprising a viscous resin suspending a substantially uniformly distributed filler material and poured into said space when each end section and its load pad are held at a desired relative spacing, the resin being hardened in situ; (b) by that the percentage of filter material and the holding of the same by the hardened resin provides that the filler material does substantially all of the work in transmitting compressive loads as between the non-maohincd surface on the pad and the non-machined surface on the end section; (c) by that it engages all of the area of each non-machined surface and such engagement provides for the respective engaged surface areas to do work in the transfer of compressive loads from the load pad to the end section.

2. In a press structure:

a frame formed by an elongated continuous loop of rolled steel comprising a pair of annular end sections respectively interconnected by center sections;

a load pad in each end section, one of said load pads having a substantially planar face; 7

a hydraulic cylinder comprising a cylindrical member having an open end, the edge of the open end engaging said planar face and the cylinder member extending in a direction towards the other load pad and being connected with said center section only by said engagement with the load pad so that the member does not participate in the transfer of load reaction between said load pads; and

a piston constructed to support the part to be worked in the press and mounted in said hydraulic cylinder for reciprocating motion along the axis thereof, motion toward the other load pad moving and exerting a load on the part for the working operations.

3. A construction in accordance with claim 2 further including a disc inside of said cylinder and supported on said planar face the periphery of the disc being adjacent the inside surface of the cylindrical member and sealing means in the space between the periphery of the disc and the inside of the cylindrical member.

References Cited UNITED STATES PATENTS 1,461,093 7/ 1923 Kershner. 1,822,939 9/1931 Stout 18-16 2,174,550 10/1939 Chapman -269 2,417,697 3/1947 Loomis 100-269 2,959,900 11/ 1960 Wollett 18-16 XR FOREIGN PATENTS 489,776 1/ 1953 Canada.

BILLY I. WILHITE, Primary Examiner.

US. Cl. X.R. 100-269

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