Patent ID: 8646356

Claim:
A spring damper made of elastic material and configured to be inserted between an inner coil spring and an outer coil spring of a double coil spring comprising: a generally cylindrical body, the generally cylindrical body being made of elastic material and having generally straight wall sections that form a polygonal cross-sectional shape when no forces are applied to the generally cylindrical body; a plurality of outer-wall convex portions formed at an outer wall of the generally cylindrical body and extending in a longitudinal direction of the generally cylindrical body from its one longitudinal end to the other longitudinal end, each of the outer-wall convex portions being located at an intersection of two generally straight wall sections and outwardly projecting, each of the outer-wall convex portions being elastically deformable in a radial inward direction, wherein the outer-wall convex portions will generate an outward radial force upon being deformed in the radial inward direction; and a plurality of inner-wall convex portions formed at an inner wall of the generally cylindrical body and extending in the longitudinal direction of the generally cylindrical body from its one longitudinal end to the other longitudinal end, each of the inner-wall convex portions inwardly projecting and being elastically deformable in a radial outward direction, wherein the inner-wall convex portions will generate an inward radial force upon being elastically deformed in the radial outward direction, wherein a cross-sectional shape of the generally straight wall sections is changed when the outer-wall convex portions are deformed in the radial inward direction and the inner-wall convex portions are deformed in the radial outward direction such that the cross-sectional shape changes from the polygonal cross-sectional shape to another cross-sectional shape.