Abstract: A rotor for an open-end spinning machine. A spinning portion of a bottomed cylindrical body has a hollow portion where twisted yarn is formed by a continuous twisting operation while gathering short fiber groups in the maximum diameter portion of the spinning chamber. A rotary shaft is joined to the spinning portion. The spinning portion is made of a silicon nitride sintered body which includes no less than 60% silicon nitride grain having an aspect ratio not less than 3, and an average grain size of from 0.1 to 10 .mu.m. The rotor is hardly damaged at a high speed rotation of 100,000 r.p.m. or more, and the yarn strength and the yarn quality are not reduced even after an extended use of the rotor for a long time.

Abstract: A cutter for a double-pile loom which cutter is fixed to a slider to slide on a rail in parallel with the cloth fell. The cutter is adapted to reciprocate crosswise in the space between the top and bottom sheets of fabric synchronously with picking to cut the pile yarns which stitch together two sheets of fabric to form piles. The cutter edge is made of a single crystal sapphire and is highly resistant to wear having its cutting characteristics maintained for a long term. Grindstones are not needed to maintain a sharpness of the cutter.

Abstract: A yarn piecing and knotting device for use in a pneumatic spinning machine for spinning slivers directly into a yarn by air jetting nozzles is disclosed. This yarn knotting device comprises means for retaining a spun yarn temporarily during a period ranging from the time of completion of the operation of a yarn knotter for connecting the spun yarn with a yarn taken out of a package to the time of resumption of winding.