Abstract: Method of forming a nozzle for use in air jet thread spinning processes, the nozzle comprising a body of selected steel material having a thread passage with an axis extending the longitudinal length of the body and one or more lateral bores entering tangentially into the passage, the method comprising the steps of selecting a raw unhardened steel material which is hardenable by heat or nitriding treatment; forming the body of the nozzle including the passage and the lateral bores out of the selected raw steel material; and hardening the formed body of raw steel material to a hardness of at least about 50 HRC.

Abstract: The mold for producing a perforated body to be used as a friction spinning element comprises a mold body provided with throughpass holes extending between the opposite mold body surfaces. Each of the throughpass holes is filled with a non-conducting material. Thus, there can be simultaneously formed by electroforming at the opposite mold body surfaces two perforated bodies which may be of the same or different thickness. By virtue of the simultaneous fabrication of the two perforated bodies the openings or perforations thereof are exactly in alignment or coincident and, if desired, these two perforated bodies can be secured to one another in superposed orientation to form a composite friction spinning element, such as a friction spinning plate or disc or an endless friction spinning belt or band.

Abstract: In the event of a yarn breakage the pressing roll of the inlet roll pair of a drafting arrangement is raised by a slubbing guide element from the inlet drafting roll or cylinder while simultaneously forming a clamping location for the slubbing or other fiber material.

Abstract: There are formed at the wall of the friction spinning element bores or holes with a predeterminate bore diameter and a coating on their side facing a fiber feed duct, the coating extending over the bore edges into the bores or holes. Each bore or hole thus formed has a diameter at the bore or hole entrance or inlet which is smaller than the bore diameter of the related bore or hole. Each bore or hole has a cross-sectional area of less than 0.283 mm.sup.2, but amounting to at least 0.07 mm.sup.2. In this way, the undesirable penetration of fibers or fiber parts into the bores or holes is prevented as far as possible when air flows through the bores or holes at the side of the coating, while retaining a hole form or configuration which is favorable from the standpoint of airflow and blockage of the bores or holes.

Abstract: The wall of the friction spinning element has bores or holes with a predeterminate bore diameter and a coating on their side facing a fiber feed duct, the coating extending over the bore edges into the bores. Each bore or hole thus formed has a diameter at the bore or hole entrance or inlet which is smaller than the bore diameter of the related bore or hole. Each bore or hole has a cross-sectional area of less than 0.283 mm.sup.2, but amounting to at least 0.07 mm.sup.2. In this way, the undesirable penetration of fibers or fiber parts into the bores or holes is prevented as far as possible when air flows through the bores or holes at the side of the coating, while retaining a hole form or configuration which is favorable from the standpoint of airflow and blockage of the bores or holes.

Abstract: Friction spinning elements, in the form of drums or discs comprising perforated friction spinning bodies are subject to the requirement that, on the one hand, the entry section of each hole should be as small as possible, in order to prevent penetration of fibers wherever possible. On the other hand, the form of each hole in the longitudinal direction, as viewed in the airflow direction, should be as favorable as possible aerodynamically so that a hole acting as a nozzle generates the lowest possible air resistance. Further, the form of the hole viewed along its length should be selected such that dirt and dust or other contaminants which may penetrate into the hole do not remain caught therein. It has been established that in galvanically formed perforated bodies there is a tendency for each hole to become larger in section with increasing wall thickness, thus giving each hole a diffusor-like longitudinal section as viewed in the airflow direction.

Abstract: In the manufacture of friction spinning drums, in order to be able to select the size of the holes or perforations, on the one hand, to oppose technological fiber loss and jamming of sucked in foreign particles and, on the other hand, to provide airflow advantages, it is proposed to manufacture the friction spinning drum from a thick-walled support and a thin-walled perforated body. As a result, holes or perforations having a sufficiently small cross-section to counteract the above-mentioned fiber loss can be formed in the thin-walled perforated body. On the other hand, holes or perforations having a large enough cross-section to prevent jamming of sucked in foreign particles or other contaminants can be provided in the thick-walled support.