Fitting for flexible plastic pipe

Abstract

A fitting, for pipe of flexible plastic material, having improved sealing and mechanical holding characteristics. The fitting includes a main body having an external screw thread terminating at a shoulder from which a coaxial, reduced-diameter, nipple projects. Annular saw tooth or buttress ribs on the nipple are dimensioned to have a slip fit into the interior of a plastic pipe section. A collet is slideable on the exterior of the pipe section into abutment with the shoulder and is radially compressed by a collet sleeve threaded onto the external threads of the fitting body. Axial slots in the collet open alternately at opposite ends of the collet so that radial compression is achieved over the entire length of the collet. Saw toothed or buttress annual ribs on the collet interior bite into the exterior surface of the pipe section in opposition to the ribs on the inserted nipple, the pipe wall being thereby radially clamped between the collet and nipple. To prevent relative rotation between the fitting and the pipe during connection and provide a positive nonrotating engagement between the collet and the fitting, the leading end of the collet is provided with a plurality of ratchet teeth which engage and cooperate with projections or ratchet dogs on the face of the shoulder of the fitting and the projections or dogs on the shoulder additionally partially bite into and become embedded in the end of the pipe.