Fastener

A fastener for coupling two relatively thin members with each member having an elongated opening therein and adapted to be placed in overlapping relationship with the elongated openings being in at least partially aligned position with respect to one another and the members being subject to severe shear loads comprising:

• a stud having an enlarged head portion and a body portion extending therefrom and means in the head of the stud for reception of a tool to facilitate rotation of the stud between the fastened and unfastened positions;
• the body portion being adapted to pass through the openings and the head being adapted to engage with the surface of the adjacent thin member and being larger than the opening therein;
• a receptacle adapted to interengage and disengage with the stud body between the fastened and unfastened positions;
• at least one spiral cam slot on one of the stud and receptacle and a corresponding cam surface on the other of the stud and receptacle whereby relative rotation therebetween will cause the cam surface to follow the cam slot between the fastened and unfastened positions, each spiral cam slot terminating in a detent for facilitating retention of the cam surface when the stud and receptacle are in the fastened position;
• spring means positioned to be biased as the cam surface follows the spiral cam slot thereby assisting in drawing the two members into tight interengagement and retaining the stud and receptacle in fastened condition;
• retention means for tending to retain the proper orientation of the fastener when the members are subjected to a shear load and to assume a substantial portion of tension load applied to the fastener so that the primary load on the coupled stud and receptacle is a shear load thereby increasing the load bearing capacity of the fastener, the retention means including a rigid washer of hard material and having a central aperture for passage of the stud body therethrough and the aperture being slightly larger in diameter than the outer diameter of the stud to provide a close fitting relationship, the surfaces forming the aperture having sharp edges so that when the stud body is passed through the two members to be fastened and the rigid washer is positioned on the stud body between the members to be fastened and the receptacle, the spring means will be resiliently deformable to permit rotation of the stud and corresponding movement of the cam surface along the cam slot between the locked and unlocked positions and the rigid washer will be positioned so that when the stud is subjected to a shear load and is rotationally biased the rigid washer will bite into the stud and will assist in retaining the stud from rotational movement thereby maintaining the coupled stud and receptacle in position for primary subjection to a shear load in contrast to a tension load.