| 摘要 |
<p>1,206,810. Winches; platform elevators. T. HEDSTROM. 10 June, 1968 [13 June, 1967], No. 27521/68. Headings B8B and B8H. A device on a working platform for lifting and lowering the platform along a cable 4 freely depending from a building &c., comprises adjacent driving and counter pulleys 2, 1, around which the cable passes, and a spring-biased wheel 3 for pressing the cable into grooves on the pulley 2 to provide the necessary frictional engagement between pulley and cable. The cable 4 passes over each pulley 1, 2 a plurality of times in a figure eight path, depending on the number of grooves in the pulleys. The pulley 2 may be either electrically driven or manually powered by foot pedals and a chain with an operator's seat and supports provided. The device may be mounted in a frame which is detachably mountable on the platform and is provided with brakes and building engaging wheels.</p> |
