Abstract: A coupling device for a tractor has a frame (4) which is mounted on the rear underside (3) of the tractor (1). A drawbar (14), with a coupling member (15), is guided in the frame (4). The drawbar (14) is moved by a slide (18) and can be swung sideways about a vertical axis. Centering pieces (34) and stop blocks with centering faces (35) and stop faces (38) engage one another to laterally align and fix the drawbar (14). In a lower position the drawbar facilitates lateral swivelling movement about the connecting pin (22). In an upper towing position the drawbar (14) is laterally fixed by the centering pieces (34) and the stop blocks (38). This results in improved control of the coupling members associated with the to be towed implement through lateral alignment of the drawbar and its automatic transfer into its centered position.

Abstract: During monitoring of the driveline of an agricultural implement in respect of overloading and the degree of loading, from a first occurrence of slip, the slip revolutions occurring during a measuring cycle are added up. If the number of slip revolutions exceeds a permissible number of slip revolutions, a signal is generated indicating an overloading condition, a new measuring cycle beginning upon release of the signal to be able to take into account the effects resulting from a change in the behavior of the tractor driver, the nature of the signal being changed responsive to the speed differential between the input speed and output speed of a friction coupling permitting relative rotation.