The invention relates to a mechanical belt transmission. It relates to a transmission in which a toothed belt 60 passes successively over a smooth drive pulley 46, a smooth return pulley 52, a toothed pulley 48 and a toothed pulley 50, the toothed face of the belt then being turned towards the two latter pulleys. In this way, the two driven members associated with the pulleys 48 and 50 are synchronised, and a certain slip is possible, especially upon startup, between the drive pulley 46 and the smooth face of the belt. Application to transmissions for centrifugal fertiliser dispensers.
