Flexible belt yarn false twisting apparatus

A yarn false twist machine having a frame, a plurality of false twisting stations positioned in side-by-side relation along the length of said frame, and means for feeding a yarn through each of the false twisting stations, the improvement wherein said false twisting stations include

• a shaft rotatably mounted to said frame and extending horizontally therealong,
• a roller fixedly mounted to said shaft in association with each of said stations,
• an endless belt rotatably mounted adjacent each roller such that the outer face of the belt is disposed in opposing, substantially non-contacting relationship with the peripheral surface of its associated roller to define opposed friction surfaces and a twisting zone therebetween,
• means for rotating said shaft and each of said belts such that the opposing surfaces run in different directions through said twisting zone,
• means for guiding a running yarn through each of said twisting zones,
• means operatively mounted adjacent the inner face of each belt for locally biasing such belt toward the peripheral surface of the associated roller only at said twisting zone,
• whereby each yarn may be continuously moved through a twisting zone while having twist imparted thereto by frictional contact between the yarn and the respective opposed friction surfaces resulting from the force exerted by the biasing means, and while the yarn engaging friction surfaces remain in substantially non-contacting relationship with respect to each other.

A yarn false twisting apparatus comprising first and second twist imparting flexible endless belts, with each belt having inner and outer faces, and with said outer faces of each belt defining a yarn engaging friction surface,

• means mounting said belts at a predetermined angle with respect to each other and for rotational movement wherein portions of the respective yarn engaging friction surfaces are disposed in opposing, substantially non-contacting relationship and define therebetween a twisting zone for accommodating a running yarn, said mounting means comprising a pair of mounting rollers for each of said belts, and means for resiliently separating the mounting rollers of each pair to tension the belt thereon, and with said separating means for said first belt providing a greater force than the separating means for said second belt,
• means for rotating each of said belts such that their respective yarn engaging friction surfaces run in different directions through said twisting zone, and
• means operatively mounted adjacent said inner face of said second belt for locally biasing said second belt toward the first belt only at said twisting zone and without generating substantial friction between said biasing means and said second belt,
• whereby a yarn may be continuously moved through said twisting zone while having twist imparted thereto by frictional contact between the yarn and the respective opposed friction surfaces resulting from the force exerted by the biasing means, and while the yarn engaging friction surfaces remain in substantially non-contacting relationship with respect to each other.

A yarn false twisting apparatus comprising

• a pair of twist imparting members, at least one of said members comprising a flexible endless belt having inner and outer faces, with one of said faces defining a yarn engaging friction surface, and with the other of said twist imparting members also including a yarn engaging friction surface,
• means mounting said members for rotational movement wherein portions of the respective yarn engaging friction surfaces are disposed in opposing, substantially non-contacting relationship and define therebetween a twisting zone for accommodating a running yarn,
• means for rotating each of said members such that their respective yarn engaging friction surfaces run in different directions through said twisting zone, and
• means operatively mounted adjacent the face of said belt opposite its yarn engaging friction surface for locally biasing said belt toward the other member only at said twisting zone and without generating substantial friction between said biasing means and belt, said biasing means comprising a piston mounted for axial movement toward and away from the adjacent face of said belt and including a pressure surface directly opposing the adjacent face and aligned with said twisting zone, and resilient means for urging said piston and pressure surface toward the adjacent face of said belt,
• whereby a yarn may be continuously moved through said twisting zone while having twist imparted thereto by frictional contact between the yarn and the respective opposed friction surfaces resulting from the force exerted by the biasing means, and while the yarn engaging friction surfaces remain in substantially non-contacting relationship with respect to each other.

A yarn false twisting apparatus comprising

• a pair of twist imparting members, at least one of said members comprising a flexible endless belt having inner and outer faces, with one of said faces defining a yarn engaging friction surface, and with the other of said twist imparting members also including a yarn engaging friction surface,
• means mounting said members for rotational movement wherein portions of the respective yarn engaging friction surfaces are disposed in opposing, substantially non-contacting relationship and define therebetween a twisting zone for accommodating a running yarn,
• means for rotating each of said members such that their respective yarn engaging friction surfaces run in different directions through said twisting zone, and
• means operatively mounted adjacent the face of said belt opposite its yarn engaging friction surface for locally biasing said belt toward the other member only at said twisting zone and without generating substantial friction between said biasing means and belt, said biasing means comprising a piston having a free end positioned to directly overlie the adjacent face of said belt and in alignment with said twisting zone, and means for conveying pressurized air between said free end of said piston and said other face and so as to form an air cushion therebetween,
• whereby a yarn may be continuously moved through said twisting zone while having twist imparted thereto by frictional contact between the yarn and the respective opposed friction surfaces resulting from the force exerted by the biasing means and while the yarn engaging friction surfaces remain in substantially non-contacting relationship with respect to each other.

A yarn false twisting apparatus comprising a pair of twist imparting members, at least one of said members comprising a flexible endless belt having inner and outer faces, with one of said faces defining a yarn engaging friction surface, and with the other of said twist imparting members also including a yarn engaging friction surface,

• means mounting said members for rotational movement wherein portions of the respective yarn engaging friction surfaces are disposed in opposing, substantially non-contacting relationship and define therebetween a twisting zone for accommodating a running yarn,
• means for rotating each of said members such that their respective yarn engaging friction surfaces run in different directions through said twisting zone, and
• means operatively mounted adjacent the face of said belt opposite its yarn engaging friction surface for locally biasing said belt toward the other member only at said twisting zone and without generating substantial friction between said biasing means and belt, said biasing means comprising an elongate tubular member having a free end, means adjustably mounting said tubular member such that said free end directly overlies the adjacent face of said belt and the distance between said free end and adjacent face may be varied, and means for supplying pressurized air to said tubular member whereby an air cushion is formed between said free end and the adjacent face,
• whereby a yarn may be continuously moved through said twisting zone while having twist imparted thereto by frictional contact between the yarn and the respective opposed friction surfaces resulting from the force exerted by the biasing means, and while the yarn engaging friction surfaces remain in substantially non-contacting relationship with respect to each other.

A yarn false twisting apparatus comprising first and second twist imparting flexible endless belts, with each belt having inner and outer faces, and with one face of each belt defining a yarn engaging friction surface,

• means mounting said belts at a predetermined angle with respect to each other and for rotational movement wherein portions of the respective yarn engaging friction surfaces are disposed in opposing, substantially non-contacting relationship and define therebetween a twisting zone for accommodating a running yarn,
• means for guiding a running yarn through said twisting zone to define a yarn path therethrough,
• means for rotating each of said belts such that their respective yarn engaging friction surfaces run in different directions through said twisting zone, and
• means operatively mounted adjacent the other face of at least one of said belts for locally biasing said one belt toward the other belt only at said twisting zone and such that the biasing force is substantially limited to an area which is coincident to the path of the running yarn,
• whereby a yarn may be continuously moved through said twisting zone while having twist imparted thereto by frictional contact between the yarn and the respective opposed friction surfaces resulting from the force exerted by the biasing means, and while the yarn engaging friction surfaces remain in substantially non-contacting relationship with respect to each other.