Patent ID: 7893369

Claim:
A ratchet wheel mechanism, comprising a camshaft circular disc ( 220 ), on the front end surface of said camshaft circular disc being disposed at least one groove ( 211 ), on the circumference of said camshaft circular disc being disposed a plurality of positioning slots ( 212 ); a driving cam ( 208 ), on the front end surface of said driving cam being disposed at least one groove ( 222 ) corresponding to said groove ( 211 ) on said camshaft circular disc, on the rim of said driving cam being disposed a plurality of angular-shaped teeth ( 235 ); a first pawl ( 255 ) and a second pawl ( 265 ); after the front end surface of said camshaft circular disc and the front end surface of said driving cam engaging each other, said groove ( 211 ) on said camshaft circular disc and said groove ( 222 ) on said driving cam forming at least one empty chamber ( 231 ), at least one resilient element ( 213 ) being positioned in said empty chamber ( 231 ); when said camshaft circular disc being at a control position, said first pawl falling into a positioning slots of said camshaft circular disc to lock said camshaft circular disc at said control position; when said driving cam starting to rotate toward a next control position, said camshaft circular disc staying at its place, said groove ( 211 ) on said camshaft circular disc and said groove ( 222 ) on said driving cam being staggered each other to compress said resilient element to store resilient potential energy; when said driving cam rotating to the next control position, one of said angular-shaped teeth pushing said first pawl out from one of said positioning slots, said resilient element pushing said camshaft circular disc to turn to the next control position, said second pawl falling into another one of said positioning slots of said camshaft circular disc to lock said camshaft circular disc at the next control position.