| 摘要 |
329,801. Thomas, S. E., and Quicktho (1928), Ltd. April 26, 1929. Sashes balanced by springs.-A spring counterbalancing device for a vertically sliding window sash has a compensating cam i by which a uniform lifting tension is exerted by the spiral torsion spring c directly connected to the cam. The cam or eccentric i is housed in a casing &c. b on the sash and connected to the fixed rail h by the cord g running on its grooved edge. As the window is raised the leverage due to the reduced radius of the cam at the point of contact of the cord g maintains a constant tension on the cord. |
