Abstract: A trolley has a chassis provided with a load-carrying assembly and a drive unit for imparting a longitudinal translational motion to the trolley. A centering finger has the shape of a polygonal cross-section, vertical-axis pyramid having downwardly-converging edges. The centering finger is supported by an element that rotatably fastens the centering finger to the chassis. The centering finger is connected to a device that can move the finger between a retracted position that is above the floor and an extended position where the finger engages a matching recess housed in a ring, which is, in turn, set into the floor. The recess is positioned in such a way that the vertical axis of the recess passes through the intersection between the longitudinal and transverse axes of a reference point and a theoretical path of the trolley, and at least one of the sides of the recess is perpendicular to the theoretical path.

Abstract: The device has a chassis with at least a translational drive unit, a load-carrying assembly, a device for moving a ring in a vertical direction between a retracted position in which it is above the ground and a pivoting position in which it engages the floor and allows the trolley to be lifted, and a device for pivoting the trolley when it is raised in relation to the ring. The device for vertically moving the ring includes a sliding element slidably mounted in vertical channels on the chassis and having fastened to its lower end a circular plate on which the ring is free to rotate. The upper portion of the sliding element supports the vertical load-handling assembly, and the element is connected to the chassis by drives for moving the trolley and the load in a vertical direction. The drives are provided with a device for detecting the completed rectilinear travel and controlled by an on-board control device.