Abstract: A polyester yarn composed of a plurality of individual fibrous materials such as endless filaments or fibers. Each of these fibrous material is provided with cross-sectional thicker portions, thinner cross sectional portions and intermediate thickness-size portions randomly distributed along the axial direction thereof in a particular condition of distribution of cross-sections of these fibrous material. The above-mentioned polyester yarn involved a textured yarn applied to a drawn polyester multifilament yarn having the above-mentioned basic condition. To produce the polyester yarn according to the present invention, it is the basic condition that the undrawn polyester multifilament yarn should be drawn under a condition of a drawing ratio below a natural draw ratio of undrawn filaments of said undrawn multifilament yarn and a drawing temperature above a crystallizing initiating temperature of said undrawn filaments.

Abstract: A false twisting machine which includes a frame having racks of thread supply spools on opposite sides with centrally disposed bobbin supporting take-up mechanisms therebetween defining corridors on opposite sides thereof with thread heaters and false twisting members disposed horizontally across the top of the machine, together with thread transport mechanisms for stretching the threads and for advancing the threads vertically upward from the thread supply spools on opposite sides of the machine across the top of the machine in a horizontal path with virtually no deviation therefrom through the heaters and false twisters and then downwardly onto the take-up bobbins for ultimate removal of the wound thread packages from the machine thereby providing a machine of greatly reduced height and capable of easy maintenance.

Abstract: In order to interlace a plurality of textured filaments and produce bundled yarn, a plurality of textured filaments having reverse twists creating opposing torques, of which the bundled yarn is to be formed, are initially subjected to a prescribed degree of tension. The tensioned filaments are then brought together and permitted to relax. Upon relaxing, the textured filaments tend to entangle with each other to form the bundled yarn having a resultant neutral torque. The entanglement is carried out without the need for supplying jets of air to the yarn to force them to tangle together.