| 摘要 |
What is proposed is a door-actuating device which is provided with a door valve (9) for the compressed-air-actuated to-and-fro movement of a door (1) and with an emergency valve (17), by means of which the two working chambers (5 and 6) of the working cylinder (4) moving the door (1) can be made pressureless, in order to actuate the door (1) by hand. The emergency valve (1) has two locks (20/21, 33/34), of which one (20/21) is releasable mechanically and the other (33/34) pneumatically. This ensures that, although a change-over from power operation to manual operation can be brought about in any operating position of the door, nevertheless, conversely, a change-over from manual operation to power operation is possible only when first the mechanical lock (20/21) is released and then the pneumatic lock (33/34) is cancelled by the driver as a result of the actuation of the door valve (17). This prevents the possibility of jamming in the region of the door as a result of the actuation of the emergency valve (17) from outside through the open door (1). <IMAGE> |
