Apparatus for producing electric current composed of a hull for a guide wheel, of a guide wheel, of a current generator body said current generator body being composed of a rotating current generator, of a box frame, of a first toothed wheel placed in a integral and concentric position with the rotor of the rotating current generator and of a second toothed wheel mechanically connected to the first toothed wheel and mechanically connected to the guide wheel, being said second toothed wheel held in contact with the tread surface of the guide wheel by the thrust exerted by an elastic component on the current generator body. CHARACTERIZED BY THE FACT THAT: - said second toothed wheel is composed of a cylindrical upper part free from teeth and of a cylindrical lower portion equipped with teeth and said cylindrical upper part superimposed and joined to said lower cylindrical portion being said cylindrical upper part with larger diameter than the cylindrical lower portion and - said box frame of the current generator body, suitable to leave uncovered the second toothed wheel of a portion sufficient to allow free access to the outer cylindrical surface of the cylindrical upper part of the second toothed wheel from outside, and - said hull for the guide wheel comprising: • a lower spray guard compartment adapted to contain, secured and free to rotate around its own center, the guide wheel; • an upper compartment joined and superimposed on said lower spray guard compartment, by means of the connection wall of the compartments, being said upper compartment adapted to receive in its interior the current generator body, said current generator body free to slide vertically within said upper compartment and positioned so as to the outer cylindrical surface of the second toothed wheel is in contact with the tread surface of the guide wheel, being said lower spray guard compartment and said upper compartment communicating through a slot, placed on the connection wall of the compartments, and being said slot suitable to receive in the middle the accessible portion of the second toothed wheel of the current generator body. • a closure cap for the open wall of the upper compartment, suitable to ensure stable said current generator body inside the upper compartment and said closure cap comprising at least one housing for at least a push button suitable to lift the current generator body and to release the outer cylindrical surface of the second toothed wheel from contact with the tread surface of the guide wheel. - said second toothed wheel is composed of a cylindrical upper part free from teeth and of a cylindrical lower portion equipped with teeth and said cylindrical upper part superimposed and joined to said lower cylindrical portion being said cylindrical upper part with larger diameter than the cylindrical lower portion and - said box frame of the current generator body, suitable to leave uncovered the second toothed wheel of a portion sufficient to allow free access to the outer cylindrical surface of the cylindrical upper part of the second toothed wheel from outside, and - said hull for the guide wheel comprising: • a lower spray guard compartment adapted to contain, secured and free to rotate around its own center, the guide wheel; • an upper compartment joined and superimposed on said lower spray guard compartment, by means of the connection wall of the compartments, being said upper compartment adapted to receive in its interior the current generator body, said current generator body free to slide vertically within said upper compartment and positioned so as to the outer cylindrical surface of the second toothed wheel is in contact with the tread surface of the guide wheel, being said lower spray guard compartment and said upper compartment communicating through a slot, placed on the connection wall of the compartments, and being said slot suitable to receive in the middle the accessible portion of the second toothed wheel of the current generator body. • a closure cap for the open wall of the upper compartment, suitable to ensure stable said current generator body inside the upper compartment and said closure cap comprising at least one housing for at least a push button suitable to lift the current generator body and to release the outer cylindrical surface of the second toothed wheel from contact with the tread surface of the guide wheel. • a lower spray guard compartment adapted to contain, secured and free to rotate around its own center, the guide wheel; • an upper compartment joined and superimposed on said lower spray guard compartment, by means of the connection wall of the compartments, being said upper compartment adapted to receive in its interior the current generator body, said current generator body free to slide vertically within said upper compartment and positioned so as to the outer cylindrical surface of the second toothed wheel is in contact with the tread surface of the guide wheel, being said lower spray guard compartment and said upper compartment communicating through a slot, placed on the connection wall of the compartments, and being said slot suitable to receive in the middle the accessible portion of the second toothed wheel of the current generator body. • a closure cap for the open wall of the upper compartment, suitable to ensure stable said current generator body inside the upper compartment and said closure cap comprising at least one housing for at least a push button suitable to lift the current generator body and to release the outer cylindrical surface of the second toothed wheel from contact with the tread surface of the guide wheel.