Multi-speed reversible transmission of countershaft construction

A multi-speed reversible transmission of the countershaft construction type for providing twelve forward speeds and six reverse speeds and comprising a housing, four shafts mounted in said housing and arranged in parallelism;

• said shafts including a power input shaft, a power output shaft, an intermediate shaft, and a high-input and reverse direction shaft;
• said power input shaft, said high-input and reverse direction shaft and said intermediate shaft each having a duplex clutch mounted thereon;
• each duplex clutch have two clutches arranged side-by-side, each clutch having a gear at one side thereof and driveable thereby, each duplex clutch also having a central gear forming a pair of clutch actuating pressure chambers and said central gears being rotatably mounted on their respective shaft, said central gear of said input shaft duplex clutch being in constant mesh with the said central gears of said other two duplex clutches, said power input shaft also having an input gear fixed thereto for delivering power to one of said clutch side gears of said high-input and reverse shaft, said output shaft having an output gear rotatably journalled thereon and in constant mesh with one of the clutch side gears of said intermediate shaft and driven thereby, said output shaft also having a high-speed range clutch detachably connected between said output shaft and said output gear, a low-speed range brake anchored in said housing, said output shaft also having a planetary gear system driven by said output gear and connected between said output gear and said low-speed range brake, whereby either said high-speed range clutch or said low-speed range brake can be used selectively with said output gear to permit drive to said output shaft.