old ELECTRO-MATIC cast iron cover plate (#1)

This is actually the second one of these now in my collections, just having arrived the other day from another collector of traffic control equipment. :-) :-) :-) That doesn't matter so much, they both did the same thing...

This is a 7lb chunk of thick cast iron measuring roughly 6" x 9" x 3/4". It was once the end cover for an electrical junction box with connections to a pressure pad sort of apparatus which was actually *set into the pavement* of a street or roadway as a "traffic detector". (that worked with other related equipment, before modern equivalent technologies developed for the purpose) Bolt holes are recessed at each corner and the underside has a part# P-255 cast in, the topside has the ELECTRO-MATIC name logo as its most prominent center feature, with "AUTOMATIC SIGNAL DIV." as the top line.

ALL THE ABOVE is common to both covers, the differences determine that this one is older with the further wording. This one is next labeled "LABORATORY FOR ELECTRONICS, INC." as the second line, with "NORWALK, CONN" and "MADE IN U.S.A." as two lines on the bottom. In later production, the molds were altered and the rest of the wording modified to reflect changes in parent company structure. This one also has a stamped "U.S. PATENT 3,187,138" that doesn't appear on my newer cover. It nearly looks more worn down than the other as well, but this is also more likely an original casting variance.