| 摘要 |
A door closing device has an upright tube closed at the bottom and containing a damping liquid, a sinker weight being arranged in the tube and connected to a flexible cord which extends out of the top of the tube for connection to a door so that a door is automatically closed when released, the sinker weight falling under gravity to pull the door closed. The device includes a passage extending through the sinker weight with a valve seat formed at the lower end of the passage and co-operating with a buoyant self-seating valve member (preferably a plastic ball which is not captive relative to the weight) which controls liquid flow through the passage when the weight sinks. As the door is opened, the weight is pulled rapidly upwards and lifts off the buoyant valve member. Preferably, the valve member substantially seals the passage in the weight and there is a clearance around the weight for passage of the damping liquid during closing of the door.
|
