Patent ID: 7228752

Claim:
A gearbox for all terrain vehicles comprising an engine having a crankshaft which drives a belt transmission mechanism of a transmission case thereby transmitting power to a final axle in said gearbox via a driven axle of said belt transmission mechanism, wherein said driven axle has an end extending into said gearbox and provided with a torque release mechanism, said torque release mechanism comprises a driving gear, a flange, a plurality of balls, a sliding disc and a resilient member on said end of said driven axle, said flange has a plurality of recesses, said sliding disc is formed with a circular groove facing said driving gear, said circular groove has a plurality of recesses aligned with said recesses of said flange thereby enabling said balls to be received therebetween, said resilient member has an end abutting against a locking member and arranged between said sliding disc and said locking member, said driving gear is freely rotatably mounted on said end of said driven axle, said sliding disc has teeth engageable with teeth of said end of said driven axle, and said driving gear is fixedly mounted on said flange.