US2021370A - Load-distributing and vibration-damping article - Google Patents

Description

Nov. 19, 1935. P. D. MALLAY 2,021,370

LOAD DISTRIBUTING AND VIBRATION DAMPING ARTICLE I Filed Nov 2, 1932 INVENfbR Paul D. Mallayy i97 $62M ATTORNEY Patented Nov. 19, 19,35

' UNITED STATES PATENT OFFICE LOAD-DISTRIBUTIN G VIBRATION DAMPIN G ARTICLE Application November 2, 1932, Serial No. 840,738 1 Claim. ((1248-54) This invention relates to any article of manufacture adapted for use as a cushion and, particularly, as a load-distributing or vibrationdamping member.

The invention comprises the novel features hereinafter described or claimed and, especially. a cushion comprising a relatively compressible body element, in sheet or pad form, and a tough, resilient facing sheet, of low coefficient of friction, united to the body element. The invention comprises also a pipe line assembly including a support of concrete or other suitable material, a

pipe supported thereby, and a cushion, of the type described, disposed'between the support and the pipe, for distributing the load and facilitating lengthwise movement of the pipe as the pipe contracts or expands under the influence of changes of temperature. vcntion comprises a vibratile member, a support therefor, and a cushion of the kind described, disposed between the vibratile member and the support, not only for distributing the load but also for damping vibrations.

The invention is illustrated in the drawing in which:

Fig. 1 shows a perspective view of a preferred embodiment of the novel article, in the form of a cushion, with parts broken away for clearness of illustration;

Fig. 2 shows a perspective view of a portion of a pipe line assembly with the cushion member of. the type illustrated in Fig. 1, in position between a section of pipe and a concrete support therefor;

Fig. 3 shows an end view of an article similar to that of Fig. 1, but with facing elements united to opposite faces of the inner or body member; and

Fig. 4 shows a perspective view of a portion of a vibration-damped railway.

The cushion comprises a relatively compressible body element I, in sheet or pad form. Preferably, this element consists essentially of a strongly compressed pad of felted fibers. The fibers may be wool, although there has been used to particular advantage, felted cattle hair in the strongly compressed form which is sold commercially as polishing felt or cushion felt and has a density of approximately 24 pounds to the cubic foot. The said element should be compressible under strong load, into conforming relationship with irregularities of surface of a concrete support or the like, and yet should have sufiicient resiliency to support a heavyv weight such as a section of a pipe line with desired cushioning effect and also be sufficiently inelastic or non-vibratile to serve as vibration-damping material. It is obvious that In another embodiment, the in- 1 the compressible pad forced into conforming relationship with the irregularities of surface of the support should show a high degree of resistance to lateral movement over the support. Ordinary,

lightly compressed, very readily compressible, 5

lightweight felts are not suitable for the preferred embodiment of the invention.

A tough, resilient, somewhat flexible, non-corrodible sheet facing element 2, of low coefficient of friction is united to a face of the element I, suitably by a layer of adhesive 3, which integrally unites the facing element to the body element, say, over substantially the entire area of one face thereof. The adhesive may be of any satisfactory composition, say a rubber cement, applied in solution in a volatile solvent, or a bituminous material. The cement should be durable under the conditions to which the composited product is to be ex: posed during use, and should cause adherence of the facing to the body element under all circumstances.

The facing element 2 may consist of sheet packing material, preferably with a graphited or otherwise lubricated upper surface, in order to reduce the coeflicient of friction of. that surface. A packing sheet that has been used to advantage is one containing approximately 70% by weight of asbestos fibers and of rubber binder compound, of which about a third is rubber and the remainder zinc oxide, anti-oxidation materials and the like, 30 and made as described in lines 62-93, page 1 of U. S. Patent 1,521,603, issued to DeWitt on January 6, 1925. In making sheet packing as described by DeWitt, the rubber compound is mixed with reenforcing fibers of asbestos or the like, and formed into a sheet on mixing rollers, one of which is warm. During the mixing the fibers become dispersed in the rubber binder. Furthermore, the rubber therein becomes partly vulcanized. After the sheet is formed as described, in the 0 said lines of the patent to DeWitt, the sheet may be further vulcanized as by being maintained at a conventional rubber vulcanizing temperature, for

a usual period of. time, in customary equipment, as, for example, between heated metal plates of plane inner surface.

The facing element should be resistant to being torn or gouged, as by irregularities of surface of an iron pipe sliding thereover, in distinction from a tender rubber sheet.

Other reenforcing fibers than asbestos may be used. Thus, wood pulp may be used in cases in which temperature resistance of the finished article or the preferred degree of durability and reenforcement by the fibers is not required.

As binder in the packing sheet, there may be used other resilient materials than rubber, as, for

example, chloro-2-butadene-L3 polymerized to a rubber-like material, as described by Carothers and others, in the Journal of the American Chemical Society, vol. 53 pages 4203-6, 1931,'and referred to hereinafter as polymerized chloroprene.

In the pipe line assembly illustrated in Fig. 2, there is shown a concrete support 4 provided with a saddle or cradle 5, into which there is placed a cushion of the type illustrated in Fig. l. The cushion is flexed to fit the saddle and, advantageously, is adhered over its lower surface by a permanent, weather-resistant adhesive 6, which may be rubber cement or bituminous material, for example. This adhesive 6 unites the resilient, yieldable, relatively compressible lower portion i of the cushion member to the support. The pipe 1 rests directly upon the facing element 2 of the cushion.

The weight of the pipe compresses somewhat the element I, and causes it to conform closely with the irregularities of the usual type in the surface of a concrete support. However, the element i does not collapse entirely under the weight of the pipe, and maintains sufllcient resiliency to distribute the load satisfactorily over the support. Furthermore, the facing element 2 of low coefilcient of friction, which, as indicated previously, may be coated over its upper surface with a graphite or other friction-reducing material, constitutes a bearing surface over which the pipe may move, say, under the influence of changing temperature upon the length of a pipe line of which the section I is a part. The fact that the facing element'z is of the type described minimizes wear upon itself and also prevents injury of the pipe or the support by each other, as the pipe moves with respect to the support.

The thickness of the cushion member used may be varied. There has been used to advantage a thickness between /2 and inch. A member so made, with strongly compressed cattle hair felt as the body element i and an adhered facing sheet of packing comprising a rubber binder and asbestos reenforcing fibers dispersed therein has been found to be compressed to not less than onehalf of its original thickness by a load.- of 2,000 lbs. per sq. inch and, after supporting such a load for 100 hours, to regain not less than of its original thickness within six hours after removal of the load. Furthermore, this cushion member, when loaded, shows only a slight increase in its length or width, say less than 5% and usually less than 2% Theimproved cushion member may be used in other assemblies than the one illustrated in Fig. 2. Thus, the cushion may be used to damp vibrations, as, for example, by being interposed between the chassis and the springs of an automobile at the position of support of the body upon the springs. For such a use, the cushion may be protected on each face with adhered facing elements 2, as illustrated in Fig. 3.

A use of the article, of type illustrated in Fig. l, in damping vibration is illustrated in Fig. 4. A vibratile member 8 subjected to varying stress, in this case a steel railway rail, rests indirectly upon a suitable support, such as the railway tie 9.

Immediately below the base of the rail there may be a railway tie plate I of metal. This tie may be conventional but preferably is plane on both faces. Disposed between the support or tie and the rail, suitably between the tie and the tie plate is the vibration-damping pad with the facing element 2 in contact with the tie plate and the compressible element I, of strongly compressed cattle hair or the like, in contact with the tie. Usual railway spikes ll secure the various elements in the assembly.

The details that have been given are for the purpose of illustration and. not restriction, and

many variations therefrom'may be made without departing from the spirit and scope of the invention.

What I claim is:

In a pipe line assembly comprising a firm support for a pipe, a cushion upon the support, and a pipe resting upon the cushion, the improvement including a cushion having a resilient, relatively compressible lower portion in conforming contact with the support and providing a high degree of resistance to movement thereover and a lubricated, tough, resilient, non-corrodible facing sheet, of low coefflcient of friction, united on one side of the upper face of the said compressible portion and contacting on the other side with the pipe.

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