Abstract: A spring-loaded device is disclosed which allows for quick, easy and accurate adjustment of the horizontal distance between the side-rails of a conveyor belt or the height of the side-rails above the conveyor belt. In one embodiment, the adjustment device is attached to the side rails by a horizontal shaft, which supports, at its other end, a perpendicular setting pole. The upper end of the setting pole can engage in any one of a plurality of recesses of varying depth situated around the perimeter of a precalibrated, rotating disc adjacent to the setting pole. The depth of each recess into which the setting pole is placed corresponds to a certain distance of movement of one of the side rails. A compression spring surrounding that portion of the shaft collar adjacent to the side rails has sufficient tension to ensure that the setting pole remains in the recess at any setting.