drive is also possible the drive speed should be regulated in such a way that the forward movement speed of the thrust unit corresponds to the travel speed of the tractor or other vehicle to which it is coupled for increasing the pulling power it must be possible to drive the thrust unit drive motor both forward and backward fig2 shows a tractor 20 with a thrust unit 22 coupled by means of a three point suspension 21 the thrust unit is sufficiently narrow so that it can be positioned between the rear wheels 23 of the tractor this arrangement is particularly favorable because it enables the thrust unit to take over part of the load of the drive wheels 23 the hydraulic lifting device 24 makes it possible to raise the thrust unit when turning and to control the degree of release of the pressure of the tractor rear wheels fig3 illustrates the manner in which a thrust unit 30 equipped with a guide pin 31 as illustrated in fig1 can be coupled to the gear unit 32 of the tractor the gear unit is provided with a sleeve 33 into which the pin 31 can be inserted the thrust unit can pivot about the longitudinal axis of the pin which makes it.