Patent ID: 7896366
Filing Date: 2011-03-01
Classification: B60B,E04G,E06C

Abstract:
1. A retractable wheel assembly cooperable with a movable structure, the retractable wheel assembly comprising: a wheel frame supporting a wheel; a pivot bracket assembly coupleable with the movable structure and secured to the wheel frame, the pivot bracket assembly being displaceable between an extended position and a retracted position; and a biasing mechanism coupled with the pivot bracket assembly, wherein the biasing mechanism urges the pivot bracket assembly toward the extended position when the pivot bracket assembly is in the extended position and urges the pivot bracket assembly toward the retracted position when the pivot bracket assembly is in the retracted position, and wherein in the extended position, the biasing mechanism acts on the pivot bracket assembly such that a predetermined downward force directly on the pivot bracket assembly via the movable structure shifts the biasing mechanism over center so that the pivot bracket assembly is displaced to the retracted position.