Helical tubular compression-spring
View Patent ↗The present invention discloses a helical tubular compression-spring assembly comprising a tubular guide-rod having a non-circular cross-section helically swept along its longitudinal-axis, and a slider with a complementary tubular bore swept helically along another path. During operation, insertion of the guide-rod into the slider from an aligned coaxial position induces elastic-deformation in the guide-rod walls arising from a geometric-mismatch between the helices, thereby storing elastic-energy. Upon release, this stored energy urges the slider toward the aligned-position, producing a restoring-force whose magnitude can be precisely tuned through variations in helical-pitches, cross-sectional eccentricities, wall-thickness, material properties, and overall dimensions. This integrated design further offers superior compactness, customizable force-displacement characteristics, enhanced durability, and simplified manufacturing compared to conventional compression-springs.
1 . A compression-spring assembly comprising:
a tubular guide-rod formed by sweeping a first non-circular cross-section perpendicular to a first longitudinal-axis along a first helical-path about the first longitudinal-axis, wherein the first helical-path has a first pitch-length;
a slider defining a tubular bore to receive the guide-rod, wherein the tubular bore is formed by sweeping a second non-circular cross-section perpendicular to a second longitudinal-axis along a second helical-path about the second longitudinal-axis, wherein the second helical-path has a second pitch-length;
wherein the first and second non-circular cross-sections comprise outer boundaries of an identical shape, and the first and second pitch-lengths are different;
wherein the tubular guide-rod and the tubular bore comprise an aligned-position in which the first and second longitudinal-axes coincide; and
wherein inserting the tubular guide-rod into the tubular bore of the slider from the aligned-position along the coincident first and second longitudinal-axes induces elastic-deformation of the tubular guide-rod due to a geometric-mismatch between the tubular guide-rod and the tubular bore arising from the difference in the first and second pitch-lengths, thereby generating a restoring-force that, upon release, returns the tubular guide-rod and the slider toward the aligned-position.
2 . The compression-spring assembly of claim 1 , wherein magnitude of the restoring-force is determined by magnitude of the geometric-mismatch, wherein the magnitude of the geometric-mismatch depending on one or more of:
a difference in the first and second pitch-lengths;
eccentricities of the first and second non-circular cross-sections;
elastic-properties of a material forming the tubular guide-rod, wherein the material is capable of reversible-deformation;
a wall-thickness of the tubular guide-rod; and
overall dimensions of the compression-spring assembly.
3 . A method of generating a restoring-force using the compression-spring assembly of claim 1 , the method comprising:
positioning the slider such that the tubular bore of the slider receives the tubular guide-rod in the aligned-position;
inserting the tubular guide-rod into the tubular bore of the slider along the first and second longitudinal-axes to produce a displacement, thereby elastically deforming the tubular guide-rod and generating the restoring-force; and
releasing the displacement, whereby the restoring-force returns the tubular guide-rod and the slider toward the aligned-position.