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Wheelchair suspension

  • US 9,913,768 B2
  • Filed: 04/20/2015
  • Issued: 03/13/2018
  • Est. Priority Date: 10/09/2009
  • Status: Active Grant
First Claim
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1. A wheelchair comprising:

  • a frame;

    first and second drive assemblies that each include a drive wheel;

    first and second suspension assemblies that each include an anti-tip linkage and a shock absorber with a spring return;

    first and second front anti-tip wheels positioned forward of the drive wheels by the first and second anti-tip linkages;

    first and second rear anti-tip wheels positioned rearward of the drive wheels by the first and second anti-tip linkages;

    the first anti-tip linkage couples the first front anti-tip wheel to the first rear anti-tip wheel such that upward movement of the first front anti-tip wheel relative to the frame causes upward movement of the first rear anti-tip wheel relative to the frame, wherein the first anti-tip linkage includes a first rigid front anti-tip pivot arm that is pivotally coupled to the frame, a first rigid rear anti-tip pivot arm that is pivotally coupled to the frame, and a first rigid connecting link that couples the first rigid front anti-tip pivot arm and the first rigid rear anti-tip pivot arm;

    wherein the first shock absorber with spring return is directly coupled to the first rigid rear anti-tip pivot arm and is directly coupled to the frame to bias the first rigid rear anti-tip pivot arm downward relative to the frame;

    the second anti-tip linkage couples the second front anti-tip wheel to the second rear anti-tip wheel such that upward movement of the second front anti-tip wheel relative to the frame causes upward movement of the second rear anti-tip wheel relative to the frame, wherein the second anti-tip linkage includes a second rigid front anti-tip pivot arm that is pivotally coupled to the frame, a second rigid rear anti-tip pivot arm that is pivotally coupled to the frame, and a second rigid connecting link that couples the second rigid front anti-tip pivot arm and the second rigid rear anti-tip pivot arm;

    wherein the second shock absorber with spring return is directly coupled to the second rigid rear anti-tip pivot arm and is directly coupled to the frame to bias the second rigid rear anti-tip pivot arm downward relative to the frame;

    wherein the first drive assembly is pivotally coupled to the frame at a first drive assembly pivot axis that is forward of an axis of rotation of the drive wheel of the first drive assembly;

    wherein the first drive assembly is biased downward relative to the frame by a first drive assembly biasing spring that is coupled to the frame;

    wherein the second drive assembly is pivotally coupled to the frame at a second drive assembly pivot axis that is forward of an axis of rotation of the drive wheel of the second drive assembly; and

    wherein the second drive assembly is biased downward relative to the frame by a second drive assembly biasing spring that is coupled to the frame.

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