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US 3,938,314 AGranted
False-twist texturing process with hollow friction twist tubes
AssigneeE. I. Du Pont de Nemours and Company
InventorGeorge Roy Trammell
Life of this patent
Estimating the term…
Abstract
False-twist texturing processes which apply twist with hollow friction tubes, fitted at each end with a toroidal bushing, are improved by using a high friction bushing at the yarn inlet and a lower friction bushing at the yarn outlet. Further improvements are provided by adjustments in the yarn inlet and outlet angles, and the speeds of the bushing surfaces.
Claims6
In the false-twist texturing process wherein synthetic thermoplastic yarn is passed continuously through a heating zone and through one or more hollow friction-twist tubes fitted with toroidal bushings to heat-set latent crimp in the yarn;
- the improvements which comprise feeding the yarn under a tension T.sub.1 from the heating zone over a high friction toroidal surface of a synthetic elastomer located at an end of a friction-twist tube at an angle .alpha. of at least 85.degree. to the yarn path, then passing the yarn over a low friction toroidal surface of an extremely hard material located at an end of a friction-twist tube at an angle .beta. of 50.degree. to 80.degree. to the yarn path and having a surface velocity no greater than that of the high friction surface, and withdrawing the yarn from the friction-twist tube under a tension T.sub.2 where T.sub.2 /T.sub.1 has a value of 1 to 2.
Dependencies are inferred from the claim text.