Abstract: A fastener to retain at least two members together under spring tension including a bolt having a fastener head shaped with two lateral extending protrusions respectively forming two shoulders for engagement of an outside surface of one of the members to be secured together. An opening is provided through the members to be secured together and at least the opening through the latter-mentioned member which is to be engaged by the shoulders of the fastener head is generally contoured to the shape of the fastener head such that the fastened head freely passes through this opening in keyhole fashion and the bolt is turned so that the shoulders of the fastener head ride up onto this outside surface clamping the members together under spring tension. Lock recesses may be provided in the outside surface of the member closest to the fastener head to receive the shoulders of the fastener head in locking engagement.

Abstract: A pipe coupling for joining interengaging ends of a pair of pipes in axial alignment comprised of a pair of semi-circular substantially identical sections adapted to mate with one another to hold the pipe ends therein. Each of the sections have cooperating locating flanges engaging corresponding surfaces in one of the pipe ends to facilitate the assembly thereof whereafter releasable securing means are disposed in aligned openings to maintain the sections in place.

Abstract: An expansion compensating pipe coupling including a circumferential head on one end of one pipe section with the head slidably received in a cylinder secured to one end of another pipe section. Means is provided for retaining the pipe head in the cylinder for checked axial movement to compensate for axial pipe expansion and contraction. One or more expansion rings may be provided on the pipe head for providing a fluid seal. The expansion rings may further be received in annular grooves in the head with passages leading from the bottom of the groove to the interior of the pipe section thereby utilizing the fluid pressure within the coupling to expand the expansion rings in good fluid seal engagement with the interior of the cylinder.