Abstract: To provide for effective sealing of a movable piston in a cylinder formed with a longitudinal slit, a motion transfer element (9, 10, 11, 12) is coupled to the piston (5) extending through the slit (3) and shaped in form of a yoke (11) extending over and around the outer surfaces of the cylinder tube (1), to retain the portions of the tube separated by the slit. The slit is sealed in the region between sealed ends (4) of the cylinder and the piston heads (6, 7) of the piston by a pair of separable and re-engageable plastic strips (18, 27), the inner strip (18) being formed with a projecting headed ridge (26) fitting in a snap-in groove (30) defined by two legs (29) extending from the outer strip.

Abstract: A stiff, form-stable elongated tubular housing (1) is formed with an axially extending longitudinal slit (12). A drive spindle (4) is retained in bearings (8) located in end flanges (2) of the housing, driven for example by a motor (M). A pair of spindle nuts (5, 6) clamp, between themselves, a tubular portion (15) of a force transfer element (14) which is located externally of the housing and moved by a web (13) passing through the slit. The force transfer element is guided on the housing by interengaging groove and projection means (20, 21), which also isolate forces applied to the force transfer element from the spindle drive.

Abstract: To form a protective cover for an elongated machine element, such as a feed spindle or the like (1), a tubular structure (7) which may be formed of a plurality of parallel strips (7a) has edges which are formed with an interengaging, interlocking but separable ridge or rib-groove construction (10, 9) similar to a slide fastener. To provide for secure interengagement and covering of a traveling element (2-4) on the spindle, a guide cone (16) is secured to the traveling element surrounding the tubular structure. The guide cone may include a hub (4) formed with a part-circumferential opening or openings (15) through which the opened guide tube portions can pass to permit the traveling element to move while providing continuous protection to the spindle upon movement thereof, the guide cone insuring reclosing of the rib-and-groove behind the movable element, and opening in advance thereof. The tube may be formed, in addition, with longitudinal guide grooves (23) in which closing elements can engage (FIGS. 8-11).