Transmission assembly for a self-propelled machine, and machine fitted with such a transmission

A transmission assembly for a self-propelled machine (20) that can be positioned between the primary motor shaft (21) and the wheels (22) of said machine, and comprising a transmission housing (1) fitted with an input shaft (3) and an output shaft (4), such as the main shaft of the wheels of the machine, a drive shaft (2) that can be driven in rotation by the primary motor shaft (21) and is linked to said input shaft (3) forming the shaft driven by an endless belt drive (11), a clutch mechanism (10) and, arranged between the input shaft (3) and the output shaft (4) for transmitting the movement from the input shaft (3) to the output shaft (4), transmission means (13) including a mechanism (5) for reversing the direction of rotational drive of the output shaft (4), the clutch and direction-reversing mechanisms (10, 5) each having a control (6, 12), said clutch and direction reversing controls (6, 12) being carried on said housing (1) and being mounted respectively and movably the one (6) between at least three positions, i.e. a neutral position, a forward position and a reverse position, and the other one (12) between at least an engaged position and a disengaged position, wherein the direction reversing control (6) forms, when said direction reversing control (6) is in neutral position, means for blocking the clutch control (12) in disengaged position that can prevent the clutch control (12) from shifting from the disengaged position to the engaged position, and the clutch control (12) forms, when the clutch control (12) is in engaged position, means for locking the direction reversing control (6) in the forward or reverse position, that can prevent the direction reversing control (6) from shifting from the forward or reverse position into the neutral position.