Rim 1 is keyed to the driving shaft and carries weights 2 which turn about axes A and B of the rim. Weights 2 are pressed by spring 3 against drum 6 which is keyed to the driven shaft. When the driving shaft reaches a definite speed, the clutch is disengaged because the weights develop a centrifugal force exceeding the tension of spring 3. Levers 4 , which limit the outward motion of the weights, are pivoted to the weights and to arm 5, rotating freely about the shaft.
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