Abstract: A self-closing residential fire hinge apparatus for closing a door during a fire includes a door hinge with a spring-actuated release mechanism. The spring-actuated release mechanism includes a spring that is pre-tensioned in an open position and a coating covering the spring. The coating is a solid material that retains the spring in the open position. The coating has a melting point less than a melting point of the spring. For example, the coating may be formed of bismuth. When the coating is heated and becomes malleable, the spring is released to a closed position. When the coating is solid and not malleable, the door hinge allows regular opening and closing of the door. The apparatus may also include a spring assembly cap, improving the aesthetics of the assembly. The spring assembly cap may be composed of copper, improving conduction of the ambient heat to melt the coating even faster.

Abstract: A self-closing residential fire hinge apparatus for closing a door during a fire includes a door hinge with a spring-actuated release mechanism. The spring-actuated release mechanism includes a spring that is pre-tensioned in an open position and a coating covering the spring. The coating is a solid material that retains the spring in the open position. The coating has a melting point less than a melting point of the spring. For example, the coating may be formed of bismuth. When the coating is heated and becomes malleable, the spring is released to a closed position. When the coating is solid and not malleable, the door hinge allows regular opening and closing of the door. The apparatus may also include a spring assembly cap, improving the aesthetics of the assembly. The spring assembly cap may be composed of copper, improving conduction of the ambient heat to melt the coating even faster.

Abstract: The device comprises a target signal transmitter to induce an electromagnetic signal in the hidden object, a position reference transmitter to transmit a signal for positioning purposes, a sensor unit to detect changes in the magnetic flux of the hidden object due to the induced electromagnetic signal and the positioning signal from the position reference transmitter, and a central unit to process and display a map of the hidden object. The initial processing of the data results in a gray-scale representation of the object, but additional data processing may be performed.