| 摘要 |
A powered door actuator (16) for opening an otherwise conventional hinged or sliding fire stop or other door comprises a driven winch, a cord (18) passing from the winch round a pully (20) on a relatively movable part of the (e.g. pivoted) door (10) before returning to a tension drum having a spring applying constant tension to the cord to take up stack. The door is drawn open by the cord when the winch is switched on, e.g. from a manually operated switch or an automatic sensor as a person reaches the door. The door is held open by braking means acting on the winch e.g. for a timed interval, and then swings closed e.g. under the action of a door closer when the winch is released. No special adaptation of the door is needed and it can be opened and closed from either side in the normal way without use of the actuator if desired. <IMAGE> |
