A robotic apparatus for the cleaning and maintenance of coal fired boilers, which is designed to operate in the high temperature environment of the combustion gasses to effectively clean and remove slag deposits of the boiler heat transfer surfaces by use of a precision directed, low pressure, low flow rate water stream. The lifter may include a lifter support movable between a first position below the hopper and a second position spaced from the first position, and a lifter carriage carried by the lifter support and pivotally movable between a retracted position and an extended position for lifting and inverting refuse collection containers to dump the refuse into the collection hopper. The pivot bearing comprises a bearing journal, a bearing hub and at least one plain bearing sleeve which is arranged between the bearing journal and the bearing hub, and a central radial force application plane of the tensioning roller is axially spaced apart from a central radial bearing plane of the pivot bearing. Resolution can be controlled by using appropriate end section potentials to control the axial spread of the ion cloud. The received user-defined codeset converter is then distributed to the one or more other users having the substantially identical category via the network, whereby the distributed user-defined codeset converter provides a customized codeset mapping table for the user and the one or more other users based on the determined category. The assembly device comprises a single first crown rigidly secured to the car and assembled by a bearing to a second crown performing securing to the mobile support.