Abstract: Apparatus for forming a plastic attachment on an article includes clamping mechanisms which position the article and form a mold surrounding the appropriate section of the article. During the process of molding the plastic attachment, the article may be moved through the mold to facilitate forming the attachment along a length of the article. The apparatus is illustrated by an annular mold for forming mating plastic couplings around the ends of tubes such as corrugated and smooth-walled metal pipes.

Abstract: A plastic coupling for joining two metal pipe sections end-to-end to form a pipe assembly. A first plastic spigot cuff is formed along the periphery of the end of the first pipe and a mating second plastic bell cuff is formed along the periphery of the end of the second pipe, such that the first and second cuffs form a bell and spigot joint with the first, spigot cuff inserted into and joined to the second, bell cuff.

Abstract: A coupling for joining metal pipes or pipe sections end-to-end to form a pipe assembly. A plastic cuff is formed on one of the pipe ends and a mating, second plastic cuff is formed on the other pipe end. In one embodiment, a wire hoop is mounted over each pipe end, the hoops are rotatable around the associated pipe ends to align the hoops, and bolt assemblies spanning the two hoops are used to tighten the hoops axially, to thereby clamp the pipe ends and compress the cuffs between the pipe ends and provide a leak-proof joint. The cuffs are selected from configurations including tongue-and-groove and bell-and-spigot. The cuffs can be formed on the pipe ends in the shop, then the pre-cuffed pipe sections can be readily assembled into stable, leak-proof, corrosion-resistant lengths of pipe in the field.