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Description
A counterclockwise torque is applied about fixed axis A to ratchet wheel 1 to hoist load Q. Pawls 2, 3 and 4 turn about fixed axis B and separately engage the teeth of wheel 1, preventing its rotation in the reverse direction and dropping of load Q. The pawls are of different length, pawl 3 being longer than pawl 4 and pawl 2 than pawl 3 by an amount equal to one-third the pitch of the ratchet wheel teeth. The provision of three such pawls is equivalent to having a ratchet wheel with three times as many (but consequently weaker) teeth. The pawls are held in engagement with wheel 1 by flat spring 5. $2775$RG,MH$
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