Patent ID: 8590869

Claim:
A spring, comprising a hollow tubular polymer body, the body having a first end portion, a second end portion, a mid-portion connecting the first end portion to the second end portion, a center axis extending between the first end portion of the body and the second end portion of the body, an inner surface extending around and facing the center axis between the first end portion of the body and the second end portion of the body, and an outer surface extending around the center axis between the first end portion of the body and the second end portion of the body, the body having a length from the first end portion to the second end portion, the inner surface of the body between the first end portion of the body and the second end portion of the body being bowed inwardly towards the center axis when the spring is in a non-compressed state, and the first end portion of the body, the second end portion of the body, and the mid-portion of the body together substantially maintaining an annular cylindrical column structure throughout the length of the body from the first end portion of the body to the second end portion of the body, such that the mid-portion of the body has a substantial portion that is in direct alignment with the first end portion of the body and the second end portion of the body when the spring is compressed until at least a predetermined maximum compression designed for a predetermined use of the spring is reached.