A torque is applied by weight Q to disk 6 which rotates about fixed axis A. Disk 6 is connected by flat spiral spring 7 to link 1. Pawl 2 slides in guides 5 of disk 6 and engages the internal teeth of fixed ratchet wheel 4. The action of spiral spring 7 causes link 1 to turn and, by means of pin a, to withdraw pawl 2 from engagement with ratchet wheel 4, compressing spring 3. After this, disk 6 turns until pawl 2 engages the next tooth of ratchet wheel 4 due to the action of spring 3. Link (crank) 1 is stopped when disk 6 begins to turn by a special mechanism (not shown). Therefore, spiral spring 7 is tensioned and the whole process is repeated.
$2714$RG,ML$