Yarn false twisting method and apparatus

A method of false twisting yarn which comprises the steps of

• operatively rotating a pair of twist imparting circular discs in opposite rotational directions about generally parallel spaced apart axes, with each disc including a yarn engaging friction surface, and such that portions of the respective yarn engaging friction surfaces are disposed in opposing, face to face relationship and define a twisting zone therebetween which is located at a point laterally spaced from the plane defined by said disc axes of rotation, while
• advancing a yarn through said twisting zone along a path extending generally perpendicular to the plane defined by said axes of rotation and between the axes of rotation, so that twist is imparted thereto by the frictional contact between the yarn and the respective opposed friction surfaces which results from the applied force, and while
• laterally deflecting the advancing yarn after leaving the rotating discs at a point downstream of said discs and in a direction generally perpendicular to the plane defined between the opposing faces of the discs and at an angle of between about 3 to 15 degrees with respect to said plane, and so that the yarn is brought into frictional contact with the peripheral edge of one of said discs at a point on the side of said plane defined by the axes of rotation opposite the twisting zone, to thereby impart twist to the yarn in a direction opposite to that imparted at said twisting zone.

A yarn false twisting apparatus comprising

• a pair of twist imparting circular discs, with each disc including a yarn engaging friction surface,
• means rotatably mounting said discs for rotation about substantially parallel spaced apart axes such that portions of the respective yarn engaging friction surfaces are disposed in opposing face to face relationship and define a twisting zone therebetween which is located at a point laterally spaced from the plane defined by the disc axes of rotation,
• means for rotating the discs in opposite rotational directions such that their respective yarn engaging friction surfaces run in different directions through said twisting zone, and
• means for guiding an advancing yarn through said twisting zone in a direction generally perpendicular to the plane defined by said disc axes of rotation so as to have twist imparted thereto at said twisting zone by frictional contact between the yarn and the respective opposed friction surfaces, and including yarn guide means positioned downstream of said discs for laterally deflecting the advancing yarn at an angle of between about 3 to 15 degrees with respect to the plane defined between the opposing faces to said discs, and so that the yarn is brought into frictional contact with the peripheral edge of one of said discs at a point on the side of said plane defined by the disc axes of rotation opposite said twisting zone, to thereby impart twist to the yarn in a direction opposite to that imparted at said twisting zone.