| 摘要 |
450,249. " On and off " castors. BARLTROP, A. C., 55, Dysons Road, Edmonton, London. Sept. 5, 1935, No. 494. [Class 52 (i)] A castor frame mounted beneath a piece of furniture is urged downwardly by spring means which, in the out of use position, is insufficient to counteract the weight of the article but which has an associated pivoted linkage serving to increase the spring action as the article is raised. In the preferred construction a collapsable parallelogram frame is employed having adjustable tension springs mounted across one diagonal, the alteration in shape of the parallelogram as the article is raised, manually or by a lever or other device, serves to increase the lifting moment exerted by the spring so that in the raised position the latter can support the weight of the article. |
