Friction crimping of synthetic threads

Claim 1

In an apparatus for imparting a false twist to a running synthetic thread by means of rotating friction elements engaging said thread and driven by said thread, the thread being subjected to a setting treatment while in a state of high twist to obtain a crimped thread; the improvement comprising two friction elements each rotatable about one of two parallel axes and each including at least one annular drive groove and at least one friction disc having a friction surface consisting of a resilient and abrasionresistant material with a high coefficient of friction, the inner diameters of the drive grooves being equal, the outer diameters of the friction discs being equal and the friction discs being axially spaced from and overlapping each other; there being furthermore provided a first annular thread-receiving groove in one friction element and thread guide means; the arrangement being such that the thread is fed via said thread-receiving groove and leaves via said drive grooves thereby entraining the friction elements for rotation; the thread being guided by the thread-receiving groove and by the thread guide means along the friction elements in a path substantially parallel to said axes of rotation and perpendicular to the friction discs; the thread guide means guiding the thread coming from the friction discs into the drive grooves.