Compression spring with cone shaped frustums subject to compression set
AssigneeMiner Enterprises, Inc.
InventorsNeal E. Wydra, David W. Geick
Life of this patent
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Abstract
A compression spring formed of an elastomer having a ratio of plastic strain to elastic strain that is greater than 1.5 to l and formed into a spherical body having cone frustums at each end to provide for a substantially constant spring rate over a major portion of its displacement. The spring is precompressed to overcome the compression set characteristics of the elastomer and to orient its molecular structure. The spring is particularly useful as a bumper spring for an automotive vehicle.
Claims8
A compression spring adapted to absorb collision energy and to be compressively displaced in response to a collision between two masses at a substantially constant spring rate over a major portion of its displacement, said spring comprising:
- a) a hollow spring member formed of an elastomer having a molecular structure and having a ratio of plastic strain to elastic strain that is greater than 1.5 to 1, the molecular structure of said member being oriented in at least one direction;
- b) said spring member having a spherical segment whose ends terminate in a transition means, said transition means comprising an integral extension of said spherical segment extending at an angle from the spherical segment;
- c) said spring having means for interconnection between two members for absorbing energy;
- and
- d) the material of said spherical segment, transition means and the angle being oriented to provide a relatively constant spring rate over a major portion of the compressive displacement of the material.
In a vehicle bumper assembly, a compression spring interconnected between the vehicle and its associated bumper, said spring comprising:
- a) a hollow spring member formed of an elastomer having a molecular structure and a ratio of plastic strain to elastic strain that is greater than 1.5 to 1the molecular structure of said member being oriented in at least one direction;
- b) said spring member having a spherical segment with ends extending therefrom at an angle, the elastomer forming said spherical segment, said ends and said angle being subject to a compression set for providing for a relatively constant spring rate over a major portion of the compression of said spring.
A preform for a compression spring comprising:
- a) a generally cylindrical body formed of an elastomer having a ratio of plastic strain to elastic strain that is greater than 1.5 to 1;
- b) cone shape frustums extending at an angle from at least one end of said cylindrical body;
- c) attaching means for mounting said compression spring between two structural members, and
- d) the elastomer of said cylindrical body, said cone shape frustums and the angle being subject to a compression set such that the elastomers is transformed into a compression spring.
A compression spring comprising:
- a) a hollow spring member formed of an elastomer material having a ratio of plastic strain to elastic strain that is greater than 1.5 to 1;
- b) said spring member having a spherical segment,
- c) a frustum extending at an angle from at least one end of said spherical segment and having substantially the same cross-sectional thickness of said segment;
- and
- d) the elastomer material of said segment, said frustum and the angle being subject to a compression set to provide a relatively constant spring rate over a major portion of the compression of said spring.
Dependencies are inferred from the claim text.