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Both
the Poole and the Barr battery clocks were made based on patents
by Arthur F. Poole. They were made in several case styles, but the
glass dome models are the most sought after.
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The first
were sold in the early 1920s and until 1934, when manufacturing under
the Poole name ceased. In 1937, the Barr manufacturing company resumed
production of the Poole designs, but sold them under the Barr name. Both
companies are thought to have been financed by the American Chain and
Cable Company of Ithica, New York.
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Poole
Clock
Height: 10 inches
Width: 8.5 inches
Depth: 4 inches
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The Poole
and Barr clocks are powered by three "D" size flashlight cells. The mechanism
is unique. A Hipp toggle mechanism allows the pendulum to swing freely
and advance the hands through a gear train using a ratchet wheel and pawl
moved by the pendulum. When the motion of the pendulum decreases‹ usually
every thirty of forty strokes‹the toggle catches a trigger notch, causing
a pivoted arm to fall against a sloped surface on the pendulum rod, thus
providing a propelling force to the pendulum. An electrical contact made
as the pivoted arm drops, energizes the electromagnets, which reset the
pivoted arm and trigger. The principle is efficient and the clocks perform
well but depend on velocity operated linkage to function quickly. Generally,
any oil on the pivots will slow the mechanics and the clock will not operate
in a satisfactory manner. Both the Barr and the Poole clocks are constructed
of steel and brass pieces mass-produced on the punch-press. Few machined
parts are used in the clocks.
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