Method and apparatus for controlling twist in yarn
AssigneeWWG Industries, Inc.
InventorsAlan H. Norris, Phillip W. Chambley
Life of this patent
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Abstract
Singles yarns are formed from a synthetic material, twisted in one direction, heat-set, cooled and false-twisted in the opposite direction. Two similarly treated strands are joined at their nodes and plied, resulting in an improved ply-twist singles twist ratio. The first twisting and heat-setting can be done concurrently using jet twisting with steam, and apparatus for accomplishing this is disclosed.
Claims9
A method of preparing a false-twisted singles yarn for incorporation in a plied yarn to obtain an increased ratio of ply twist to singles twist therein comprising the steps of
- imparting a first predetermined amount of twist to the singles yarn strand in a first direction;
- heating the twisted strand to a temperature at least as great as the glass transition temperature of the material;
- subsequently cooling the twisted strand below the glass transition temperature;
- and
- imparting a second predetermined amount of twist in the opposite direction to that portion of the strand which was subjected to said twisting, heating and cooling steps.
A method of forming a plied yarn comprising the steps of
- continuously longitudinally moving a plurality of singles yarn strands formed of a synthetic material having a known glass transition temperature;
- imparting first predetermined amount of twist to portions of each of said strands
- heating said portions of each of the twisted strands to a temperature at least as great as the glass transition temperature of the synthetic material;
- subsequently cooling said portions of each of the twisted strands below the glass transition temperature;
- imparting second predetermined amounts of twist to said portions of each of the strands which are subjected to said twisting, heating and cooling steps, said second predetermined amounts of twist for each strand being in a direction which is opposite to the direction of the first predetermined amount of twist;
- and
- bringing the strands into contiguous relationship and permitting the strands to ply together into a self-twisted, plied yarn.
An apparatus for treating a yarn strand comprising
- means for forming a singles yarn strand from a material having a known glass transition temperature;
- first fluid jet twist means downstream of said means for forming for receiving said strand and selectively imparting twist in either direction to said strand, said twist means having an axial yarn passage therethrough;
- means for supplying steam under pressure to said passage in said first twist means;
- an elongated tube extending coaxially away from the output end of said passage;
- second fluid jet twist means downstream of and spaced from said tube for receiving said strand and selectively imparting twist in either direction to said strand, said second twist means having an axial yarn passage therethrough;
- means for supplying air to said second twist means at a temperature below said glass transition temperature;
- and
- means for receiving said strand from said second twist means.
Dependencies are inferred from the claim text.