SIGNAL ACTIVATED DOOR HINGE

摘要

This Signal Activated Door Hinge closes a door when activated by an external electrical signal. The hinge is typically the central hinge of a three-hinge door, with its upper part attached to standard hinge plates, and its lower part being an elongated cover tube housing its electro-mechanical components The lower part of the hinge plates is attached to an upper sprocket pinned to a lower sprocket which supports a central drop shaft extending to the bottom of the cover tube. An annular drop weight slides on the drop shaft and in the readiness position is latched to a pivoted release lever near the top of the drop shaft. A bi-metallic muscle wire, which changes length when electrically heated, controls the rotary position of the pivoted release lever. When an electric signal, such as from a fire alarm, is transmitted to the circuitry of the muscle wire, it rotates the release lever away from the drop weight which unlatches and slides down the drop shaft under gravity, impacting the bottom of the drop shaft and pulling it down to open the sprocket connections. This causes a coiled spiral activation spring inside the upper sprocket to unwind and thereby rotate a hinge plate to close the door. To reset the hinge, the signal is canceled and the drop weight pulled up to the latched position in the release lever, ready for the next signal activation. The signal closes the door from any position, whether fully or partly open or closed. This compact hinge has distinct advantages over external door closing mechanisms.