Explosion-proof mercury lamp lighting unit

Claim 1

AN EXPLOSION RESISTING LIGHTING UNIT HAVING A MERCURY VAPOR LAMP, SAID UNIT COMPRISING A METALLIC TUBULAR BODY, A GLOBE DETACHABLY SECURED TO THE LOWER END OF SAID BODY AND FORMING A FLAME TIGHT CLOSURE THEREFOR, A SUPPORTING MEMBER SECURED TO THE UPPER END OF THE BODY AND BEING FORMED AT ITS UPPER END WITH MEANS FOR ATTACHMENT TO A CONDUIT CONTAINING THE FEED WIRES FOR THE UNIT, SAID SUPPORTING MEMBER BEING CLOSED AT ITS LOWER END AND FORMING IN CONJUNCTION WITH THE BODY A FLAME TIGHT COMPARTMENT COMMUNICATING WITH SAID CONDUIT, A LAMP RECEPTACLE AND BALLAST ASSEMBLY MOUNTED IN SAID BODY, SAID ASSEMBLY COMPRISING A METALLIC PLATE DETACHABLY SECURED IN SAID BODY IN HEAT CONDUCTING RELATION THERETO AND EXTENDING TRANSVERSELY OF THE BODY INTERMEDIATE THE CLOSED END OF SAID SUPPORTING MEMBER AND SAID GLOBE, AN IRON CORE BALLAST MOUNTED ON THE UPPER SURFACE OF SAID PLATE, MEANS CLAMPING THE CORE OF SAID BALLAST AGAINST SAID PLATE IN HEAT CONDUCING RELATION THERETO, AND A LAMP RECEPTACLE FIXED TO THE UNDERSIDE OF SAID PLATE, CONDUCTORS SEALED IN THE CLOSED END OF SAID SUPPORTING MEMBER AND EXTENDING FROM SAID COMPARTMENT INTO THE AREA ABOVE SAID ASSEMBLY, SAID CONDUCTORS BEING CONNECTED TO SAID BALLAST AND SAID BALLAST BEING CONNECTED TO THE TERMINALS OF THE LAMP RECEPTACLE.