Abstract: In connection with a device for retracting and advancing a thread processing element in relation to a threadline it is provided that the retracting and renewed advancing is caused solely by switching on a drive motor in a direction opposite its normal operational direction of rotation. For this purpose a drive member, which is maintained fixed against relative rotation in this direction of rotation, and another drive member which can be rotated in this direction of rotation in relation to the first by way of a drive motor, are provided, which change a rotating movement into an axial movement.

Abstract: A compound or composite powder which includes metallic or ceramic whiskers embedded in a metallic or ceramic matrix as host material, the whiskers have a length between 5.times.10.sup.-6 m and 2.times.10.sup.-4 m and diameters between 2.times.10.sup.-7 m and 1.times.10.sup.-5 m, and are embedded in the matrix with a volume proportion of whisker content between 1 to 50% (by volume), the reference being to a pore-free compacted compound/composite material; the whiskers being made of SiC, Si.sub.-3 N.sub.-4, Al.sub.-2 O.sub.-3 or ZrO.sub.-2 and are embedded in a ceramic matrix being Al.sub.-2 O.sub.-3, Al.sub.-2 O.sub.-3 +from 5 to 40% ZrO.sub.-2 +from 0 to 5% Y.sub.-2 O.sub.-3 or ZrO.sub.-2 with 3 to 15% Y.sub.-2 O.sub.-3 or Si-nitride or Si-carbide. Alternatively the whiskers are made of Si.sub.-3 N.sub.-4, Al.sub.-2 O.sub.-3, ZrO.sub.-2 or W and the matrix is made of W, Mo, Fe, Ni, Co, Cu or an alloy thereof.

Abstract: In a large antifriction bearing consisting of two bearing races and at least two track systems disposed therebetween each having a rolling element row which rolls on associated tracks of the bearing races, one rolling element row (4, 11) is of a different material to the other rolling element row (5, 12) to enable bearing properties such as clearance or bias, rotation resistance and wear compensation to be influenced without external action or interventions on the bearing and also to permit compensation of different track tolerances at the periphery (FIG. 1).