Abstract: A pulley consists of a pulley basic body which has a cylindrical outer circumferential surface. Sitting on this cylindrical outer circumferential surface is a tire which is of sandwich-like design with regard to its radial extent. This results in a plurality of rings concentric to one another. The ring which is furthest on the inside in the radial direction and the ring which is furthest on the outside in the radial direction are in each case elastomeric rings, whereas a reinforcing ring is located between them. The elastomeric outer ring is harder than the elastomeric inner ring, so that a very abrasion-resistant surface is achieved, over which the rope runs, whereas the elastomeric inner ring provides for adequate resilience. The reinforcing ring is provided in order to distribute the rope load as uniformly as possible over the elastomeric inner ring.

Abstract: On an eccentric screw pump or an eccentric screw motor, both the outer wall and the inner wall of the jacket (21) have a helicoid form. In order to stabilise the cross-sectional profile of the jacket (21) in the vicinity of the ends and to allow it to be simply coupled to the other housing sections (5, 6), a retaining ring (28) sits on each end of the jacket (21). The retaining ring contains a through channel (32), whose cross-sectional surface has a form which substantially corresponds to the cross-sectional surface that is delimited by the inner wall (23) or outer wall (24).

Abstract: A rotor (4) for an eccentric screw pump or a subsurface drilling motor consists of a straight, essentially cylindrical core element (21), onto which a shell (22) is forged by a cold-forging process. The forging gives the shell (22) the helical external form required for eccentric screw pumps (1). The rotor (4) described can be produced by non-cutting shaping, which is of considerable advantage in particular in the case of large rotor dimensions, since no waste material is produced.