Screw jack for the support of plate structures, with continuous/intermittent height adjustment, has a center body with left/right threads sliding within a tube carrier in outer sleeves and balls through openings to ride in the threads

摘要

The screw jack, to give a continuous or intermittent height adjustment to support a structure, has at least one tubular or cylindrical body (1) with left-hand and right-hand threads running within each other. The upper end of the body is attached to the supported structure in a durable or release mounting. The body has a sliding movement within a tubular carrier (4), which has a number of openings (5) at right angles to the symmetrical axis on separated planes. The gaps between the planes match the recessed grooves of the threadings on the center body. Ring-shaped sleeves (6) slide on the outer carrier, with at least one inner surface (11) at an angle to the axial line, to form a wedge with the outer surface of the carrier. Or the inner sleeve surface has radial wedge surfaces matching the openings. Balls (7) and/or rollers are in the openings between the threads at the inner body and the inner wall surface of the outer sleeve. The sleeves are locked together in a release positive fit through a circular spring (14).