Interchangeable illuminated sign

Claim 1

A sign illuminated by a fluorescent light comprising, in combination, a rectangular box having an open rectangular front face and having inwardly-extending lugs at the front face to receive fasteners, a rectangular frame of a size to cover the front of the box and having thin flanges extending inwardly around the entire periphery of said frame and defining a rectangular sign opening, said frame having raised bars extending longitudinally thereof on the inner surface thereof and located outwardly of the thin flanges which define longitudinal edges of the sign opening, said raised bars having fastener openings therein, threaded fasteners extending through said fastener openings and being threadedly received in said lugs, a fluorescent light tube located centrally within said box and extending longitudinally thereof, electrical wiring for said light tube located within said box and extending to the outside of said box in the form of an electric cord, a plurality of thin, opaque plates which are rectangular in shape and uniform in height, said plates having transparent indicia in the form of numbers, letters, or designs formed therein, a plurality of spacer blank plates of the same height as said opaque plates serving as spacers between appropriate ones of said thin, opaque plates, as required, the height of all of said plates being substantially equal to the distance between the inner edges of said thin flanges extending longitudinally of the sign opening, each of said plates having thin, rear edge flanges extending beyond the ends of the plate and a rear, thin side flange extending beyond one side edge of the plate, with the opposite side edge of the plate having a front, thin side flange extending beyond the opposite side edge of the plate to engage the rear side flange of an adjacent one of said plates, with said end rear flanges being behind and in contact with the inner surfaces of the longitudinal frame flanges and outer edges of said end flanges being in substantially abutting relationship with edge portions of said raised bars, a light-transmitting plate extending over the backs of said plates and in contact therewith, and clamping means fastened to said raised bars and engaging the back surface of said light-transmitting plate.