Yarn friction false twist device

Friction false twist device of the class comprising three equiangularly spaced parallel shafts each having a set of rotary friction discs equally axially spaced and arranged so that discs of the sets overlap one another substantially when viewed axially and a strand passing through the centre of the device follows a zig-zag spiralling path as it contacts the rim of each disc in turn, wherein one of the sets of discs is a datum set and is mounted on a support member with its shaft projecting relative to a flat reference surface of the support member and with its shaft axis at a location which is fixed relative to the parallel axes of the shafts of the other two sets of discs, the latter shafts being carried on respective pivotal members each having a flat undersurface seated upon the flat reference surface of the support member or a surface co-planar therewith, and the shafts being mounted on the pivotal members with their axes equally spaced from fixed axes about which the pivotal members are adjustable, the latter axes being equally spaced from each other and from the shaft axis of the datum set of discs, and means being provided for locking the pivotal members in selected positions of adjustment.