Abstract: The mounting mechanism comprise: on the straddle carrier side, a main frame mounted on wheels and suitable for selective lifting and lowering of the main frame in relation to the ground; on the equipment side, an auxiliary frame suitable for fixing to the main frame using detachable connection mechanism allowing it to be detached; and of a number of struts for supporting the auxiliary frame on the ground when the auxiliary frame is separated from the main frame. The main frame and the auxiliary frame both comprise a pair of parallel, substantially horizontal girders. One of the frames comprises mechanism for longitudinal guidance able to co-operate with the girders on the other frame to guide the two frames in along each other, when the main frame moves longitudinally with respect to the auxiliary frame supported by the struts.