US2157418A - Spring cover - Google Patents

Description

S. W`. LIPPITT SPRING COVER May 9, 1939.

Filed NOV. 20, 1937 INVENT OR.

V uw 9 Patented May 9, 1939 UNITED STATES iPATENT OFFICE 3 Claims.

This invention relatesbroadly to covers for the laminated road springs of automobiles and more specifically to an elastic tubular casing formed for assembly over the end of the spring 5 and capable of tensible engagement therewith.

The spring covers in` commercial use at the present time are, for the greater part, formed of a plurality of thin sheet metal sections con structed to encompass the spring, and to ex therewith through the articulated organization of the sections. Such covers have been found objectionable due to the initial cost thereof, the cost of assembly upon the spring, the rapid deterioration of the cover, the rattles and noise developed herein and because such structures failed to preclude the admission of water and foreign matter from the interior of the cover. V

The only other type of spring cover that attained any commercial success was made of oil cloth cut and sewed to envelop the spring and formed for assembly thereon through a longitudinal slot closed by lacings, glove snaps and similar devices. These covers were likewise objectionable due to the rapid deterioration of the fabric because it was impossible to keep the cover drawn taut over the spring and in intimate en.- gagement therewith because the material and structure would not preclude the entry of water and foreign materials into the interior of the cover and due to the inflexible character of the fabric.

The present invention contemplates a cover formed of an elastic knitted fabric impregnated and coated with rubber or a similar yieldable material and formed as a tube adapted to sheath the spring in compressive engagement.

Another object of the invention is to provide an elastic cover which is adapted. to retain an appreciable amount of lubricant therein andi which when stretched over the spring' will maintain a constant pressure thereon and thereby force the lubricant between the leaves of the laminated spring.

Another object of the invention is to provide a rubberized knitted fabric tube which possesses sufficient elasticity to accommodate the assembly thereof upon the spring by stretching the material over the spring eye and clips while drawing the cover over the body of the spring.

Other objects and advantages more or less anciliary of the foregoing and the manner in which all the various objects are realized will appear in the following description which, considered in connection with the accompanying drawing, sets forth the preferred embodiment of the invention.

Referring to the drawing in which the preferred embodiment of the invention is illustrated:

Fig. 1 is a side view of an automobile road spring of the conventional leaf spring type show' ing the improved spring cover thereon in longitudinal section;

Fig. 2 is a transverse section through the spring and cover shown in Fig. l, the section being taken on the plane indicated by the line 2-2 of Fig. 1; and

Fig. 3 is a transverse sectional view similar to the section illustrated in Fig. 2. but including a valve to facilitate the application of a lubricant.

Referring first to Fig. l, the automobile spring ii! chosen for purposes of illustration, comprises the usual main leaf Il formed with an eye l?! in the end portion thereof, a plurality of successively shorter leaves I3 and the customary spring clips I4 for the retention of the shorter leaves.

The improved spring cover embodying the present invention is formed of an elastic knitted fabric l5, which may be knitted in tubular form of suitable configuration for snug engagement upon the spring when stretched and drawn thereover, or may be formed from a flat knitted sheet having the longitudinal edge portions thereof overlapped to form a tube of the characteristics referred to above. In knitting the fabric it is desirable to form the loops 0r entwine textiles in such a manner as to facilitate the maximum eX- tensibility of the fabric in the direction which, in assembly, will be transverse the spring so that the fabric may be stretched over the spring eye l2, clips I4, or other protrusions forming a part of the spring assembly without danger of fracture of the fabric. The knitted fabric, whether in a tubular or flat sheet form is impregnated and coated with rubber or a similar elastic material which may be calendered therein, then vulcanized or otherwise suitably cured. In a knitted fabric of this character the openings between the loops or the interstices in the fabric permit the entry of the rubber through and through and is so imbedded and keyed therein as to form a homogeneous mass in the sense that it is difiicult to pull or strip the rubber therefrom as may be done with a closewoven fabric, which by the very nature of its construction precludes the penetration of the rubber into the fabric and the interlocking relation thereof with the textile strands. After the rubber is vulcanized, the spring cover thus formed may be readily assembled upon the spring by stretching the large open end of the cover over the spring eye I 2, then drawing the cover down over the body of the spring. If a rubber compound is used which is subject to deterioration in the presence of grease, the surfaces of the cover may be coated with an asphalt paint or a similar grease resisting material I6, as shown in Fig. 3. However, rubber compositions and similar elastic materials, known to repel the deleterious action of grease, are available and may be employed when lubricants are used which attack the elastic coating.

In the use of the spring cover made from a rubber composition subject to deterioration in the presence of grease, the spring leaves and interior walls of the cover may be copiously covered with a past'e formed of an inert fluid and graphite, such lubricant can be readily renewed from time to time by merely stripping the end portions of the cover back upon itself and again coating the surface of the spring with the lubricant. Lubrication of the spring may also be effected by forcing the graphite, or grease, when a grease resisting elastic is employed, through the valve or coupling I1 in the wall of the cover as shown in Fig. 3. Such method of lubrication is particularly effectious with the present invention since the elastic cover will permit the entry and storage of an appreciable amount of lubricant I8 and will, in addition effectuate the uniform distribution of the lubricant along the spring.

In the construction of the spring cover t'he size of the opening through the tube is smaller than the body of the spring for which the cover was designed, thus when the cover is assembled upon the spring it will be sufficiently stretched or tensioned to maintain a constant pressure upon the spring and constantly urge the lubricant between the leaves thereof.

Although the foregoing description is necessarily of a detailed character, in order that the invention may be completely set forth, it is to be understood that the specific terminology is not intended to be restrictive or confining, and that various rearrangements f parts and modifications of detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

l. A spring cover formed of a sheet of knitted fabric having rubber calendered thereon, said sheet being folded to form a tube substantially equal in length to the portion of the spring intermediate the suspension bearings thereof and smaller than corresponding transverse sections of the spring, said fabric being knitted for greater extensibility in one dimension of the sheet than the other and being arranged within the tube with the extensible dimension of the sheet transverse the axis of the spring.

2. A cover for automobile leaf springs comprising a conical tube of knitted fabric, said tube comprising a sheet of fabric knitted for extensibility throughout the width thereof and limited longitudinal distention and having a yieldable material possessing the characteristics of rubber calendered thereon, said sheet being arranged in the construction of the tube to facilitate transverse extensibility and limited longitudinal distenton thereof.

3. A spring cover comprising a tube of knitted fabric knitted with greater distensibility transversely than longitudinally, said tube having rubber calendered upon the fabric and being formed for tensive engagement upon the spring.

STEPHEN W. LIPPI'I'I.

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