Gear boxes

Claim 1

A gear box comprising a relatively long input shaft, a relatively short output shaft in coaxial relation and operatively connected with said input shaft and relatively rotatable therewith, two spaced lay shafts disposed in parallel relationship with said input and output shafts, a plurality of fixedly mounted input shaft gears on said input shaft, at least one rotatably mounted lay shaft gear disposed on each of said respective lay shafts and permanently meshing with a corresponding one of said fixedly mounted input shaft gears, at least one rotatably mounted input shaft gear on said input shaft, at least one fixedly mounted lay shaft gear disposed on at least one of said lay shafts and permanently meshing with said rotatably mounted input shaft gear, two output shaft gears rotatably mounted on said output shaft, two further fixedly mounted lay shaft gears disposed on each of said respective lay shafts towards one end thereof and each permanently meshing with one of said two output shaft gears, means for alternatively engaging one of said output shaft gears for operative transmission of torque between the two lay shafts and the output shaft; a synchronizer on said input shaft for engaging said input shaft with said input shaft rotatably mounted gear, at least one further synchronizer on each of said lay shafts for selectively engaging said respective lay shaft with a respective rotatably mounted lay shaft gear, and all forward gears synchronized by synchronizers.