MULTIPLE BALLS SUPPORTED PUSH ACTUATOR

摘要

The push actuator (10) has a fixed base (12) which rotatably carries a selectively rotatable rotor (44, 46, 48, 50). A horizontal band (24) has a lower portion stacked in a helical pattern and has an upper portion engaged by the upper portion of a vertical band (30), to form a vertical telescopic column (32). The lower portion of the vertical band (30) is stacked in a spiral, separately from the horizontal band (24), the horizontal band (24) is supported on the rotor (44, 46, 48, 50) with a helical ball support track (70) along which a number of balls (72) can roll and slide, to allow substantially frictionless rotation of the rotor member (44, 46, 48, 50) while the horizontal band (24) remains rotatably stationary. A ball re-circulation unit (76) allows the balls (72) to circulate between the top of the track (70a) and the bottom of the track (70b). Upon rotation of the rotor (44, 46, 48, 50), the vertical column (32) is formed by the horizontal band (24) being lifted and its turns being spaced through its engagement on the rotating helical ball support track (70), and by each turn of the vertical band (30) being inserted between two vertically successive turns of the horizontal band (24).