Method and apparatus for heat setting fastener elements

Abstract

A method of heat setting spaced fastener elements on a fastener chain includes contracting a formed thermoplastic wire constituting the fastener elements, while heating the fastener chain to which the formed wire is affixed, until the pitch of the fastener elements attains a predetermined value smaller than the value of a desired pitch and subsequently cooling the formed wire while the wire is stretched to provide the desired element spacing. Apparatus for practicing the method includes a rotated heating wheel having circumferential teeth the pitch whereof is less than the desired element pitch in order to engage and contract the formed thermoplastic wire while the fastener chain bearing the wire is heated, a rotated cooling wheel having circumferential teeth the pitch whereof is equal to the desired element pitch in order to engage and stretch the molded wire while the fastener chain, received from the heating wheel, is cooled, and means for heating the fastener chain as the chain traverses the outer periphery of the heating wheel.

Dependencies are inferred from the claim text.