Patent ID: 8214970
Filing Date: 2012-07-10
Classification: A61G,B60B,B62B,Y10T

Abstract:
1. A wheel system comprising: a frame; a wheel rotatably mounted to the frame about a first axle defining a first horizontal axis and adapted to rollably engage a support surface; a lifter movable into and out of a retracted position and adapted to lift the wheel over a vertically disposed obstacle along the support surface, the lifter being defined by a generally C-shaped elongated member disengaged from the first axle and having first and second terminal ends facing opposite each other and interconnected by a curved intermediate body lying substantially completely within a periphery of the wheel when the lifter is in the retracted position, the first terminal end being pivotably and separately mounted to the frame about a second axle spaced from the first axle and defining a second horizontal axis, the second axle being located outside the periphery of the wheel, the second free-terminal end defining a contact surface and leading portion that is non-rotatable relative to the intermediate body and engageable with the obstacle for enabling lifting of the wheel; and a spring member separately located between a lower portion of the frame and a midportion of the curved intermediate body between the first and second terminal ends, wherein the contact surface and leading portion of the lifter is adapted to establish initial contact with the obstacle, and thereafter the lifter is configured to pivot about the first terminal end such that the wheel is lifted and translated over the obstacle; and wherein the spring member comprises a helical spring configured to bias the lifter into a fully retracted position in which the wheel can operate with minimal interference.