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.

Barr Clock
Height:
11.75 inches
Diameter: 7.25 inches
(at base)
 
Poole Clock
Height:
10.75 inches
Diameter: 7 inches
(at base)
 

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.

Poole Clock
Height:
10 inches
Width: 8.5 inches
Depth: 4 inches
 

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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