US 5,957,441 AGranted

Hourglass-shaped elastomeric compression spring

AssigneeMiner Enterprises, Inc.

InventorKevin B. Tews

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Abstract

A compression spring formed from an elastomer member having a ratio of plastic strain to elastic strain that is greater than 1.5 to 1 is disclosed. The elastomer spring member defines an elongated axis between opposed ends of the spring and has a molecular structure. A periphery of the elastomer member has a series of axially spaced annular portions of increased cross-sectional area with an annular waistline portion disposed between adjacent annular portions of increased cross-sectional area to provide the elongated member with a series of axially spaced hourglass configurations arranged in end-to-end relation relative to each other. The hourglass configurations along the periphery of the elastomer member allowing the elastomeric spring to collapse upon itself during compression thereof while maintaining a substantially constant outside diameter for the areas of increased cross-sectional area. The internal molecular structure in each annular portion of increased cross-sectional area along with the annular waistline portion being oriented in a predetermined manner during precompression of the elastomeric member to eliminate any compression set characteristic of the elastomer material.

Claims16

Dependent claims

An axially elongated elastomeric spring for use within a hollow guiding device, said elastomeric spring having an effective operating range defined between zero deflection and excessive deflection which causes radial outward bulging of the spring sufficient to establish an interaction between an outer diameter of the elastometic spring and the guiding device thereby effecting the load deflection curve of the spring, said elastometic spring comprising:

an axially stacked series of one-piece spring units for absorbing impacts imparted to said spring, said stacked series of spring units combining to define an elongated axis for said spring;
with each spring unit being foamed of an elastomer material having a molecular structure and a ratio of plastic strain to elastic strain that is greater than 1.5 to 1, the molecular structure of at least one portion of each spring unit being orientated in at least one direction;
and
wherein each spring unit is configured with annular upper and lower portions joined together by an annular waistline portion, with the annularly configured upper and lower portions having generally coequal outside diameters which are both greater than an outer diameter of said waistline portion such that each spring unit has a generally hourglass configuration, with the upper portion of each spring unit having a top and the lower portion of each spring unit having a base, and with slanting upper and lower wall sections joining said top and said base with said waistline portion whereby during load deflection of said spring the configuration of each spring unit causes the upper and lower wall sections to move toward each other with substantially no increase in the outside diameter of said upper and lower portions of each spring unit thereby maintaining an outer diameter of the spring in radially spaced relation from the guiding device during a spring work cycle.

1 more element

Dependencies are inferred from the claim text.