Abstract: A control device for use in a dual function machine includes a first disconnecting device for connection between a first operator's control knob and at least one control valve usable for controlling a first function of the machine. A second disconnecting device is provided for connection between a second operator's control knob and at least one second control valve usable for controlling a second function of the machine. The disconnecting devices are arranged for mounting in actuating relationship to a swivel-type operator's seat, the first disconnecting device being actuated for disabling the second function when said seat is in a first position for operating the first function and the second disconnecting device being actuated for disabling the first function when the seat is in a second position for operating the second function.