Abstract: A supplementary spring assembly (104) is fitted to three consecutive turns (86.1, 86.2, 86.3) of a vehicle suspension coil spring (102). The spring assembly (104) includes a central torsion-producing portion (105) having a pair of half-turn torsion springs (106, 108). The half-turn torsion springs (106, 108) are connected to each other by a C-shaped bight portion (109) which engages an intermediate turn (86.1) of the coil spring (102) in a clamping fit. First and second arms (110, 112) extend from opposite ends of the torsion springs (106, 108) and pass slidably through complemental apertures (114) formed in mounting blocks (116). The mounting blocks (116) include a clamping arrangement in the form of a C-shaped recess formed in the block (116) which is sized to fit around non-adjacent turns (86.2, 86.3) of the coil spring (102).

Abstract: A device for strengthening a coil spring comprising a torsion spring having a helical formation and two arms that are engageable with the coil spring. A deformable plastics body, such as polyurethane, is received within the helical formation resistively to oppose a reduction of the diameter of the formation whereby the device has a progressive action.