Patent ID: 8429772

Claim:
A helical coil spring comprising a wire formed into a multiple revolution central spiral portion defining a central spring axis and terminating at opposed ends with unknotted upper and lower end turns disposed in planes substantially perpendicular to the spring axis, each of the upper and lower end turns being substantially U-shaped and having a long leg and a short leg joined by an arcuate connector having a bump, the long leg being at the free unknotted end of one of said end turns and the short leg being at the free unknotted end of the other of the end turns of the coil spring, the lateral distance between the long leg of one of the end turns and the central spring axis being greater than the lateral distance between the short leg of the end turn and the central spring axis, the connector of one of the end turns being on the opposite side of the central spiral portion than the connector of the other end turn of the coil spring, wherein the wire is a high tensile strength wire having a tensile strength greater than 290,000 psi.