Detachable quarter-turn blind hole fastener

Claim 1

An assembly of a fastener and a panel and a frame including in combination, a panel formed with an opening having a major diametral dimension and a minor diametral dimension, a frame formed with an opening having a major diametral dimension and a minor diametral dimension, said frame opening major and minor dimensions extending respectively generally in the directions of the panel minor and major dimensions, a fastener formed with a shoulder adapted to engage the outside of said panel around said opening, a stud mounted in said bushing for rotary and for limited axial movement, a cross pin on said stud adjacent to the inside of said panel, said cross pin having a length less than said major diametral dimensions and greater than said minor diametral dimensions, means for biasing said stud for axial movement of said cross pin toward said bushing, means forming spaced locking elements on said bushing over which said cross pin moves in response to rotary movement of said stud in one direction and concomitant axial movement against the action of said biasing means to align said cross pin with the minor dimension of said panel releasably to retain said fastener on said panel, and stops on said bushing angularly disposed between said locking elements, said stops extending axially for a distance greater than said limited axial movement of said stud to prevent rotary movement of said stud beyond the point at which the cross pin engages the stops, said cross pin riding over said locking elements and into alignment with the minor dimension of said frame in response to rotary movement of said stud in the other direction to engage the inner surface of said frame releasably to secure the panel to the frame.