We just received a few mechanical clock modules with an unusual mechanism from a surplus supplier. These clocks have plastic belts or strips with numbers on them, which are pulled through the clock mechanism in a continuous loop. The most interesting thing about this module is that the numbers and plastic backing are translucent, which allows the numbers to be backlit with LED's.
I haven't a clue what these were originally designed for. I don't think they were originally intended for commodity consumer clocks, because there is a separate switch on the front of the module that allows the alarm contacts to be closed at any time. Why would the average alarm clock user need to arbitrarily turn the alarm on with a switch? There is another, separate switch on the front of the module to handle normal resetting of the alarm. The switches are the two metal posts sticking out on either side of the display.