US Patent 8251384 Axle and suspension

An improved skateboard truck in which a curved support surface is configured to make line contact that sweeps back and forth along a working surface associated with a truck's axle as the axle oscillates through a cycle including left-turn and right-turn orientations. The axle pivots around the locus of line contact during at least a portion of the cycle. From a frame of reference associated with the support surface, the lines of contact are parallel at max-left and max-right turn configurations. Preferred embodiments include structure arranged to resist departure from a zero-turn configuration while permitting micro-turn adjustment. Structure may be included to limit the range of rolling rotation of the deck about its length axis.