Patents by Inventor David Millard Christy

David Millard Christy has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5711580
    Abstract: The device is a footrest support structure for attachment to the frame of a wheelchair. A footrest is carried on the end of a telescoping leg pivotally engaged to a wheelchair frame. The telescoping leg automatically extends as it is elevated, by means of a folding link that engages the two parts of the leg. The link is engaged as well by a lever lock that permits the first arm to slide freely in a first direction but not in a second direction until the lock is actuated. The first arm of the folding link is pivotally engaged to the upper leg at a first pivot point intermediate the ends of the first arm and the leg, respectively, for pivoting the arm in a generally vertical plane. The second arm is pivotally engaged at its lower end to the lower leg at a second pivot point. The distance between said first and second pivot points extends as the footrest support structure is elevated, thus causing the leg to elongate.
    Type: Grant
    Filed: September 13, 1996
    Date of Patent: January 27, 1998
    Assignee: Advanced Mobility Systems Corporation
    Inventors: Hugh Walter Barclay, David Millard Christy