Simplex Master Clock
Circa 1955
Simplex is famous for their time clocks. However, this is a master clock for controlling bells to signal the different times of the day
for shift changes, start of school or recesses. The clock was only 32 inches high, had a nice looking oak case, and the dial was easy to read.
But it was not a very prictical design and you don't very often find one.
It used the clock's minute hand and the clock dial and hands
as half of a series circuit and a separate wheel with tabs as the second half. When the wheel tab would make contact with the control switch and the clock's minute hand would actually
make contact with a tab mounted on the clock dial, electrice current would flow to a bell causing it to ring. The minute hand was actually part of an electric switch.
The wheel was not precise and the tabs required a tool to mount.
This system was short lived.
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