False twisting apparatus and method

A method of false twisting a yarn and converting from S to Z twist or vice versa, and comprising the steps of

• providing a pair of twist imparting circular discs, with each disc including a yarn engaging friction surface, and with at least one of said discs being relatively thin and flexible, and with said discs being mounted for rotation about parallel spaced apart axes and such that portions of the respective yarn engaging friction surfaces are disposed in opposing, face to face relationship,
• providing at least one pressure applying member, with said pressure applying member being positioned intermediate said axes of rotation of said discs and so as to locally bias said one flexible disc toward the other disc and thereby define a twisting zone,
• rotating each of said discs in opposite directions about their respective axes, while advancing a yarn along a path of travel through said twisting zone in a direction perpendicular to a plane defined by the axes of rotation of said discs so as to have twist imparted thereto by frictional contact between the yarn and the respective opposed friction surfaces resulting from the force exerted by said pressure applying member, and then
• reversing the respective positions of said discs such that each axis of rotation is disposed on the opposite side of said pressure applying member from its original position, and reversing the direction of rotation of each disc, while maintaining the same friction surfaces in contact with the yarn and the same yarn path of travel, to thereby convert from S to Z twist, or vice versa.

A method of false twisting a yarn and converting from S to Z twist or vice versa, and comprising the steps of

• providing a pair of twist imparting circular discs, with each disc being relatively thin and flexible and including a yarn engaging friction surface on each side thereof, and with said discs being mounted for rotation about parallel spaced apart axes and such that portions of the respective yarn engaging friction surfaces are disposed in opposing, face to face relationship,
• providing a pair of pressure applying members, with said pressure applying members being aligned with each other and so as to locally bias respective ones of said flexible discs toward the other disc and thereby define a twisting zone,
• rotating each of said discs in opposite directions about their respective axes, while advancing a yarn along a path of travel through said twisting zone in a direction perpendicular to a plane defined by the axes of rotation of said discs so as to have twist imparted thereto by frictional contact between the yarn and the respective opposed friction surfaces resulting from the force exerted by said pressure applying member, and then
• moving each of said discs axially along its axis of rotation so that the opposite friction surface engages the opposite side of the yarn which such disc formerly engaged, while maintaining the same direction of rotation of each disc and yarn path of travel, to thereby convert from S to Z twist or vice versa.

A method of false twisting a yarn and alternately imparting S and Z twist to produce a novelty yarn, and comprising the steps of

• providing a pair of twist imparting circular discs, with each disc including a yarn engaging friction surface, and with at least one of said discs being relatively thin and flexible, and with said discs being mounted for rotation about parallel spaced apart axes and such that portions of the respective yarn engaging friction surfaces are disposed in opposing, face to face relationship,
• providing a first pressure applying member, with said first pressure applying member being positioned intermediate said axes of rotation of said discs and on one side of the plane defined by such axes of rotation, and so as to locally bias said on flexible disc toward the other disc and thereby define a first twisting zone,
• providing a second pressure applying member, with said second member being positioned intermediate said axes of rotation and on the other side of the plane defined by such axes, and so as to locally bias said one flexible disc toward the other disc and thereby define a second twisting zone,
• rotating each of said discs in opposite directions about their respective axes, while advancing a yarn along a path of travel through said twisting zone in a direction perpendicular to a plane defined by the axes of rotation of said discs so as to have twist imparted thereto by frictional contact between the yarn and the respective opposed friction surfaces resulting from the force exerted by one of said pressure applying members at the associated twisting zone, while
• alternately actuating said first and second pressure applying members to produce alternating S and Z twist portions in the advancing yarn.