A counterclockwise torque is applied about fixed axis A to ratchet wheel 1 to hoist load Q. Reversible pawl 2 turns about fixed axis B and engages the teeth of wheel 1, preventing its rotation in the reverse direction and dropping of load Q. Pawl 2 is held in engagement with wheel 1 by spring 3. If the position of load Q is changed to Q', a clockwise torque is required to hoist it and pawl 2 is reversed to the position shown by dash lines.
$2770$RG,MH$