Abstract: A belt tightening device is provided for open-end spinning machines which is capable of ensuring good belt thrust, eliminating vibrations, and reducing the noise level of the machine. Each bearing box of a belt tightening roll is attached to the end of a pair of flat legs extending in spaced apart relationship to each other along the endless driving belt. The legs are connected to the bearing box either by spring elements, or are formed themselves by leaf springs.

Abstract: The invention solves the problem of ejecting impurities out of a cleaning aperture in the fiber separating device of an open-end rotor spinning unit, particularly when there are various contaminations of fibrous slivers and of different kinds of textile fibers being processed. For this purpose an air flow regulator is provided in the separating device in an air supply duct communicating with the cleaning aperture. According to the invention, the air flow regulator is provided with an air directing wall near the outlet of the air supply duct and thus directs air flow into the cleaning aperture toward the fiber opening cylinder.

Abstract: The invention relates to an open-end rotor spinning unit and particularly solves the problem of the relationship between a fiber defining stud of a separator, a fiber supply duct and a yarn take-off duct passing through the separator and the stud.According to the invention, there is established a dimensional relationship of the defining stud to the mean staple length of fibers, and the orientation of the supply duct at an acute angle to the front wall of a cylindrical projection partially engaging into the spinning rotor.In inner section of the peripheral wall of the defining stud is curved in the direction of a natural fiber flow trajectory into the direction of the spinning rotor rotation while the outer section is either in contact with or radially set back from the cylindrical wall of the projection at a distance of up to 4 millimeters from the edge of the wall.

Abstract: Apparatus for separating fibers in open-end spinning machines, having a combing-out cylinder by which a fibrous sliver supplied by a feeding device is separated in a combing-out zone provided between a card clothing of the combing-out cylinder, and an operating wall of an insert, the cross-section of said zone decreasing, at least in the introductory portion thereof, in the fiber flow direction while the separated and combed-out fibers are conveyed through a duct into a rotary spinning chamber. The insert is provided with at least two differenly concave faces for providing different combing-out zones, said insert being adjustable into positions in which any of said concave faces is adapted to cooperate in providing the combing-out zone, the insert being held in a desired one of its respective positions.