| 摘要 |
PCT No. PCT/GB96/00746 Sec. 371 Date Apr. 1, 1998 Sec. 102(e) Date Apr. 1, 1998 PCT Filed Mar. 28, 1996 PCT Pub. No. WO96/30693 PCT Pub. Date Oct. 3, 1996The disclosure relates to a vertically operating linear actuator for a multi-stage extendible column for carrying a cinematograph or TV camera. A load representing the weight imposed by the multi-stage column with its camera is indicated at (10), a vertically extending gas strut at (11) and a base (12). A piston rod (15) of the strut carries a rotatable disc mounted on a pivot pin eccentrically to its geometric center to provide a varying radius of rotation between the offset center and disc periphery (21). A tether (22) extends over the disc and is secured at one end to an anchorage (23) on the base and the other end supports the load (10). The effective force applied by the strut to the weight (10) will be determined by the effective radii of the disc (20) at points where the tether engages the disc. The varying radii are arranged to compensate for the diminishing force generated by the gas strut (11) at its extends to maintain a constant force on the load (10) so that the latter remains imbalanced throughout its range of movement. |
