Abstract: The stator comprises a rigid tubular casing and an elastic lining which is tightly enclosed by the casing and symmetrical with respect to the longitudinal center axis of the stator. The inner surface of the lining forms a multiple thread and, in cross section, consists of a number of sections near the axis equal to the number of courses of the thread and an equally great number of concave arcs. The lining has a minimum thickness each at the concave arcs and a maximum thickness each near at least two of the transitions between the sections near the axis and the concave arcs.

Abstract: Improved joint seal for the rotor drive of an eccentric screw machine comprises a sealing cuff of elastomeric or thermoplastic material with a radially exterior rim bead connected to the outer joint sleeve by means of an exterior supporting ring, and a radially interior rim bead with a generally axis-parallel ring apron radially outward thereof. An interior supporting ring with an axis-parallel annular limb connects the radially interior rim bead of the cuff to a coupling rod of the joint with the annular limb of the interior supporting ring clasped between the radially interior rim bead and the ring apron disposed outwardly thereof on the sealing cuff. The radially exterior rim bead may be connected to the joint sleeve by means of an exterior suporting ring similar to the interior supporting ring.