Switch knob lighting device

Claim 1

A switch having a lightable knob, comprising an elongated movable operating rod for effecting make-and-brake operations of the switch, said operating rod having an axially extending central opening through the entire length thereof; a transparent rod mounted in said opening and extending substantially the entire length thereof; means defining a chamber integrally formed with the operating rod or rigidly fixed thereto for movement therewith and communicating with the inner end of said central opening; a light source in said chamber in confronting relationship to the inner end of said transparent rod; a knob mounted on the outer end of the operating rod and having formed therein a conic recess which progressively enlarges in diameter toward the outer end thereof; a conic lens fixedly disposed in said conic recess at a fixed distance from said light source; and a lightable indication plate mounted on the outer end of said knob and closing the outer end of said conic recess; the inner end of said transparent rod facing said light source and the outer end of said transparent rod facing said lens whereby light emitted from the light source advances straight through the transparent rod and is diffused by means of the lens thereby to illuminate the indication plate from the interior; a switch case and means supporting said operating rod for longitudinal sliding movement relative to said switch case; an insulator fixedly attached to said switch case and provided with a plurality of fixed contacts connected to an electric source; a contact holder slidably disposed in said switch case and being fixedly connected to said operating rod and carrying a movable contact for selective engagement with said fixed contacts, said contact holder having said chamber formed therein, said light source being an electric lamp fixedly disposed in said chamber for movement with said contact holder; and lead wires extending from the lamp and connected to either a further switch or said fixed contacts; said operating rod being rigidly inserted into the contact holder to communicate with said chamber and adapted to slidingly shift the contact holder along said insulator and to stop the holder at positions in which said movable contact comes into contact with one of the fixed contacts thereby to light the lamp.