Patents Assigned to Perma-Tite AB
  • Patent number: 4793752
    Abstract: There is provided a flanged drive-head lock washer for use in combination with a wedge-action-type fastener, wherein the fastener includes a bolt or screw member having a cam nut or cam head. The flanged drive-head washer is formed having a nut-like body and a plurality of wrench-engaging sides to match the sides of the particular nut or head of a bolt. The upper face of the washer comprises a plurality of cam members arranged to lockingly engage the corresponding cam surface formed on the contacting surface of the cam nut or cam head. The lower surface of the washer is formed having a frictional surface defined by an enlarged annular flange. The matching cam surfaces are arranged to align the corresponding wrench-engaging side walls, whereby the cam nut or cam head can be simultaneously rotated during removal of the fastener without affecting the integrity of the fastener.
    Type: Grant
    Filed: May 11, 1987
    Date of Patent: December 27, 1988
    Assignee: Perma-Tite AB
    Inventor: Bengt O. Frieberg