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US 4,356,668 AGranted
Method and apparatus for door protection
OwnerRichard P. Wagnerinventor
Life of this patent
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Abstract
This invention is a method and an apparatus by which a barrier is automatically placed before partially opened doors, which barrier is automatically removed when the door is fully opened and safe for travel. The invention includes means to detect when the door is fully opened and thereupon to activate barrier removal means, together with barrier placement means automatically activated at any time when the door is not fully opened.
Claims1
The method of preventing passage through a partially opened door comprising:
- (1) closing a door;
- (2) placing a barrier in position across the door opening area;
- (3) establishing a predetermined attitude of opening of the door;
- (4) providing means suitable to remove the barrier when the door reaches the predetermined condition;
- (5) sending a signal to the barrier removal means when the door reaches the predetermined condition;
- and (6) removing the barrier upon receipt of the signal.
3 more elements
Dependencies are inferred from the claim text.