Abstract: A stator assembly for a progressive pump or motor, comprising a resilient material stator (10) having a helical bore (12) therethrough, the cylindrical outer surface (14) of the stator having a plurality of axially extending circumferentially spaced outward projections (16). A rigid generally tubular member (22) has cooperating recesses (24) and may be formed of a unitary tube or of a plurality of shell elements with a cooperating clamp arrangement (32-36). The side faces (18,20) of the projections are flat and either parallel to one another or are inclined towards one another in the radially outward direction.

Abstract: A rotor and flexible drive shaft assembly for a progressive cavity pump or motor in which the rotor 10 is provided with an end portion 12 and the drive shaft 20 is provided with a head portion 18. A transverse spirally wound sheet metal pin 24 is engaged in the first passage 16 in the end portion 12 and a second passage 22 in the head portion 18, a retaining sleeve 26 preventing the pin from falling out, the retaining sleeve itself being held in place by a circlip 32.