Abstract: Slubs are removed from an open-end spinning chamber by the application of suction to a debris-extraction duct by a valve opened to a suction line as the chamber is opened to a suction line as the chamber is opened for cleaning.

Abstract: Friction spinning apparatus comprises two rollers arranged in parallel closely spaced relationship so as to define therebetween adjacent the line of closest approach a throat and a fibre feed means for feeding fibres into the throat for twisting into yarn as shown in G.B. No. 2042599. The surface of each of the rollers has a roughness characteristic at most 250 micro inches (6.25 microns) and the roller having its surface moving from the fibre feed means into the throat has a roughness less than that of the other roller by from 20 to 100 micro inches (0.5 to 2.54 microns).

Abstract: A method of open-end spinning a yarn formed of two different types of fibers of staple fiber and a yarn formed thereby in which most of the outer fibers are formed of one type of fiber and most of the inner fibers are formed of the other component. The types of fibers are integrally linked by orienting and distributing the fibers as they approach the open end such that they lie substantially parallel to the open end and overlapping whereby part of some of the fibers of the inner type of fiber wrap around some of the fibers of the outer type of fiber.

Abstract: This friction spinner includes an opening roller system for feeding fibers to and through a feed duct to a throat formed between the adjacent peripheral surfaces of two parallel drum rollers rotating in the same direction, one roller perforate so that air may be drawn thereinto through its peripheral surface, and the other imperforate, and rotating such that the imperforate roller rotates out of the throat and the perforate roller rotates into the throat when viewed from above. Yarn formed at the throat, by frictional contact of the fed fibers with the rotating surfaces, is withdrawn along the throat. The fiber feed duct is arranged to feed the fibers in an airstream having a direction inclined to the yarn axis of yarn being formed at the throat and providing a component of fiber movement opposite to the direction of yarn withdrawal, which is to say transverse thereto.

Abstract: A friction spinning apparatus including two rollers defining between them an elongate yarn formation area from which yarn is drawn axially of the rollers, has a fibre feed duct extending to a position between the rollers and closely adjacent the yarn formation area. The fibre feed duct includes a surface along each side adjacent the respective roller which surface is curved to follow the curvature of the adjacent portion of the roller.

Abstract: The yarn formation area of a friction spinning apparatus, in which the rotating friction rollers and the feed duct lie closely adjacent, is quickly and simply cleaned of remaining fibres at a yarn break and protection is provided against damage caused by excess fibres entering the area. One of the rollers, which is imperforate, is mounted for pivotal movement away from the area and at a break suction through the other roller is temporarily closed off from one end of the area toward the opposite end to eject the remaining fibres. Return movement of the roller is guided to ensure proper return to the operating position.

Abstract: A roller for a friction spinning apparatus comprises a hollow perforated base member of aluminium or similar material, with a chrome dioxide plasma coating at most 0.004 inch. The perforations are at most 0.03 inch in diameter and provide a ratio of hole to total area of at least 25%. The thickness of the base member is at most 0.125 inch.

Abstract: Spinning is started on a friction spinning apparatus by drawing the end of yarn back to a position adjacent the surface but in such a condition that it is free from the influence of the suction through the surface. This is done by closing off the suction while the end is in the position so that the yarn is drawn by an additional suction source into an adjacent position. The yarn end is drawn from one end of the surface to lie along the surface by gradually closing off the suction from that end toward the opposite end. Subsequently the suction is reopened to bring the yarn end under its influence to draw the end onto the surface so the fibre feed and take-up can be restarted.

Abstract: A friction spinning apparatus comprises an opening roller system for feeding fibres in a feed duct to the throat formed between the adjacent peripheral surfaces of two parallel drums rotating in the same direction. Yarn formed at the throat, by frictional contact between the fed fibres and the surfaces, is withdrawn along the throat. The fibre feed duct is arranged to feed the fibres in an airstream having a direction inclined to the yarn axis and providing a component of fiber movement opposite to the direction of yarn withdrawal. A suction opening in the duct wall facing away from the drums causes an additional airstream across the duct parallel to the yarn axis to turn the fibres from the direction of inclination to a direction more nearly parallel to the yarn axis as they approach the throat. One of the drums is perforated for suction through its surface, the other is imperforate and formed with a resilient surface of a rubber material.

Abstract: An apparatus for twisting a fibre strand to have repeated along its length alternating zones of opposite twist comprises a fluid vortex device having two fluid inlets and a valve controlling fluid flow to the inlets. The valve comprises a hollow cylindrical rotatable valve member and a sleeve having a number of outlet ports surrounding the member. Fluid supplied to the hollow member is distributed to the outlet ports by rotation of the member. Plastics dry bearings between the member and the sleeve act to prevent improper flow of air along the abutting surfaces. The vortex device comprises a member formed with a bore, the bore having a wide port into which the fluid is injected through the inlets and a restricted port forming a venturi of diameter of the order twice that of the yarn. A plug through which the yarn passes at the end of the bore remote from the venturi inhibits escape of air from that end.

Abstract: A method of forming a self-twisted fibrous structure comprises twisting two strands of similar count such that each has repeated along its length alternating zones of opposite twist, converging the strands at a convergence point such that they partly untwist around one another to form a self-twisted structure and acting on the strands at or downstream of the convergence point by applying further alternating zones of opposite twist so as to modify the strand to ply twist ratio of the structure. The further twist is applied at a point not greater than one half cycle length from the first twist point and at a phase difference 20.degree. to 60.degree. following.