Patents by Inventor Mathias H. Riesgraf

Mathias H. Riesgraf 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).

  • King pin lock for semi-trailers
    Patent number: 3982413
    Abstract: This is a lock which can be quickly and easily attached to the locking groove of the king pin of a trailer to block entrance of the king pin into the attaching slot of the "fifth wheel" of a tractor, the lock having a pair of pivotally connected pin-surrounding locking segments with a snap-in lock element to hold the segments in closed position and also incorporating a safety warning sign to indicate the presence of the lock on the king pin and prevent inadvertent damage to the lock or the tractor unit.
    Type: Grant
    Filed: March 17, 1975
    Date of Patent: September 28, 1976
    Inventors: Richard A. Stone, Mathias H. Riesgraf