Method of producing covered elastic yarn

A method of producing a covered elastic yarn comprising the steps of covering an unstabilised elastic polymeric core yarn by passing the yarn through a winding station whilst winding a heat-shrinkable continuous filament covering yarn thereon, and collecting the covered yarn, and thereafter transferring the covered unstabilised yarn to a heat treatment machine, unwinding the covered unstabilised yarn from a package and passing the yarn through said machine wherein it is concurrently subjected to a drafting action, to draw the core yarn and reduce its tex count, and to a heating action, of less than 1 second duration, to stabilise the core yarn and set it temporarily to a desired tex count at least 10 percent lower than the tex count of the unstabilised core, said drafting action extending the core yarn to at least 150 percent of its unextended length and, with the heating action, reducing the elongation to break of said yarn to 150 percent or less, and said heating action producing a shrinkage in said covering yarn of at least 5 percent.