| 摘要 |
<p>In a device for counterpoising a range of cable supported loads, the inner end of a torsion spring is fastened to a shaft. A cam having an axially extending spiral cable groove of continuously varying radius is journaled on the shaft and the outer end of the spring is fastened to the cam. Means are provided to preload the spring to the onset of the useful portion of its torque versus revolutions relationship. A load supporting cable is wound on the cam with one end fastened at the largest radius end of the cam and with the load supporting portion of the cable having a first point of tangency with a smaller radius point in the groove when the load is in its uppermost position. Any load subject to a predetermined vertical travel distance will be counterpoised at all elevations by selecting a predetermined point of tangency in which case only one cam is needed for a range of load weights. The cam serves as a composite of individual cams for different loads. A new safety device and a new means for reducing nonconcentric winding of the counterpoise torsion spring are also provided.</p> |
