US Patent 7626321 Spring coil shunt for light string socket

A mechanical shunt for use in a socket of a string of lights resides in an otherwise typical lamp of a string of lights. The present shunt is a coiled spring shunt held by one of the electrical terminals in the socket so that it is cantilevered toward and in electrical contact with the other electrical terminal. The central portion of the spring shunt has a larger diameter. The lamp holder has bottom that, upon insertion of the holder into the socket, presses down on the central portion of the spring shunt so that its first end is moved out of electrical contact with the first electrical terminal, thereby allowing electrical current to pass through the filament in the bulb.