A conveyor device, comprising a) a plurality of rack elements arranged in a first row to define a first conveyor track. The conveyor device also comprises b) a plurality of rack elements arranged in a second row to define a second conveyor track. The conveyor device includes c) a robot unit with a traction device and a driving device, wherein said traction device is adapted to move said robot unit along said first or said second conveying direction and said driving device is adapted to engage said coupling interface of said movable carrier device to drive said movable carrier device. The conveyor device also includes d) a cross traverse rack element adapted to take up said robot unit, wherein said cross traverse rack element comprises a traverse movable load carrying device having an upper traverse load surface adapted to take up an object and a traverse coupling interface.