Lift-off device for oven chamber doors of a coke oven

A lift-off system for the doors of oven chambers of a horizontal chamber coke oven having handles that can be raised and lowered between a bottom and a top terminal position and can be moved, in an intermediate engagement position, in the direction of the longitudinal axis of the oven chambers comprising door positioning means for opening and closing a door and for raising and lowering same into and out of a cleaning position, first and second counters coupled to a pulse generator constructed and arranged to generate pulses as a function of the raising movement of the door, first switch means responsive to the movement of the door, said first counter responsive to the movement of said switch to control the raising of the door by counting the number of pulses which can be preselected and corresponds to a constant preliminary raising movement of the door handles, second switch means located above said door, said second counter being constructed as a forward-backward counter, which counts the pulses between the upper position of the preliminary raising movement and a cleaning position, located above it and determined by said second switch means, said counter counting forwards or backwards depending on the direction of movement of the door handles, and limiting the lowering movement of the door from the cleaning position into the upper position of the preliminary raising movement.