Changeable display unit for use in a sign device

Claim 1

An interchangeable display unit for use in a sign device which comprises: a case containing an electromagnet disposed therein and extending along opposite sides thereof, said case including a case aperture disposed at a front side thereof and a plurality of biased members disposed at a rear side of said case for mounting to a baseboard, a fixed plate containing a plate aperture disposed at the center thereof, said fixed plate being bent with a bending angle of less than 90° at is center to form wing portions which extend therefrom, said fixed plate being attached to said case so that their respective apertures coincide, and a movable plate rotably attached to said fixed plate at the center thereof, said movable plate having various colors on its surfaces which are different from or the same as the color on the surfaces of said wing portions, respectively, and a circular permanent magnet which faces said electromagnet through said apertures whereby after each display unit is inserted into the baseboard by the plurality of biased members, when the electromagnet is activated, the movable plate is selectively moved between the wing portions of the fixed plate in a short response time whereby the colors on the opposite side surfaces on the movable plate and the fixed plate are selectively combined with each other on the baseboard to create a desired sign.