| 摘要 |
The door panel is contained inside the frame with the weight-compensating unit consisting of at least one helical spring (11) pre-tensioned by being turned and one end on a horizontal shaft (7). The shaft and helical spring are positioned directly on the door panel with each end of the shaft protruding beyond the door leaf supports with a driving wheel in the form of cog or chain wheel (15) engaging with vertical chains (13,14). |
