Abstract: The invention relates to a coupling for working vehicles, such as tractors, which coupling comprises on the working vehicle two fixedly connected members, two locking bars and two levers for cooperation with two coupling members on the work attachment. The two fixedly connected members are joined by means of a pipe arranged between their facing sides, in which pipe the two locking bars are slidably mounted for movement through orifices in said members to positions inside and outside of the outwardly facing sides of the latter. The locking bars work within the free surfaces of the members defined by their edge surface. The coupling members have an inner wedge-shaped cavity corresponding to the outer wedge shape of the fixedly connected members, and have orifices in their walls having the same dimensional relationship to their inner wedge-shaped cavities as the locking bars have to the outer wedge shape of the fixedly connected members.