Industrial robot system for work at at least a work station comprising at least a docking station (5) at the work station, a platform (3) that carries a robot unit (2) and that is movable to the docking station. A connection device (1) is configured to connect the platform to the docking station. The connection device comprises a primary connection unit on the platform and a secondary connection unit on the docking station. A first protruding member (11a) protrudes out from one of the primary connection unit and a first space (11b) exists at the secondary connection unit. The first space receives the first protruding member in a connecting direction (10). A locking device (15) provides locking of the platform to the docking station when the first protruding member is inserted in the first space. A power unit (17) exerts, when the first protruding member is inserted in the first space, a force that is directed in the connecting direction and that by the locking device presses the platform towards the docking station, wherein the platform is fixed at the docking station in a certain position.