Gearbox with no break in torque

A gearbox comprising:

• forks, each fork comprising a guide finger;
• a control barrel comprising guide members, each guide member being configured to guide the guide finger of a corresponding fork;
• gears forming gear ratios;
• a primary shaft and a secondary shaft connected together by the gears;
• each gear comprising a gear wheel rotatably linked to one of the primary shaft and the secondary shaft, and an idler pinion mounted on the other of the primary shaft and secondary shaft, which mesh with one another, each idler pinion comprising first claws;
• sliding gears to ensure shifting of the gear ratios, each sliding gear being configured to cooperate with one or two idler pinions;
• said each sliding gear being configured to move towards associated one or two idler pinions by the fork;
• said each sliding gear comprising second claws complementary to the first claws of the one or two idler pinions cooperating with said each sliding gear;
• wherein all of the forks, the sliding gears, the idler pinions and the guide members of the control barrel of the gearbox forming a gear selection system;
• the corresponding fork, an associated sliding gear, the one or two idler pinions cooperating with the associated sliding gear and the guide member associated with the corresponding fork forming elements of a subassembly of the gear selection system;
• and
• wherein one element of each subassembly comprises an elastic return element, when a new gear ration is engaged, the elastic return element being configured engaged, to uncouple the associated sliding gear from the idler pinion of a gear forming a previously engaged gear ratio.