Electric lamp having an outer bulb

Abstract

The lamp comprises a discharge vessel ( 2 ), which is sealed in a vacuum-tight manner and is arranged in an outer bulb ( 12 ) which only partially surrounds the discharge vessel. The outer bulb comprises an open tube, which is closed by sheet-metal parts.

1 . An electric lamp having an outer bulb and having an inner vessel, in particular a discharge vessel, arranged therein, the inner vessel being elongate and having two ends, the ends having seals, and the outer bulb only partially surrounding the inner vessel, wherein the outer bulb is an open tube made from glass and having two ends, at least one end being sealed by an essentially planar sheet-metal part made from resilient sheet metal, the sheet-metal part being fixed on the associated seal.  
     
     
         2 . The lamp as claimed in  claim 1 , wherein the sheet-metal part is in the form of a disk, the outer diameter of the disk approximately corresponding to the outer diameter of the end of the open tube.  
     
     
         3 . The lamp as claimed in  claim 2 , wherein lugs, which bear on the inside against the end of the tube are distributed over the circumference of the outer diameter of the sheet-metal part.  
     
     
         4 . The lamp as claimed in  claim 2 , wherein the sheet-metal part has a central opening which is matched to the cross section of the seal.  
     
     
         5 . The lamp as claimed in  claim 4 , wherein the sheet-metal part is held securely on the seal by the seal being cylindrical with a given diameter and opening out over one edge into an extension part which is in the form of an open tube having a relatively large diameter, the diameter of the central opening of the sheet-metal part being matched to that of the seal.  
     
     
         6 . The lamp as claimed in  claim 5 , wherein the zone is divided into a plurality of tabs by means of radially extending slots.  
     
     
         7 . The lamp as claimed in  claim 3 , wherein a clamping action of the sheet-metal part on the tube is achieved by the lugs being bent out in the manner of a roof.  
     
     
         8 . The lamp as claimed in  claim 1 , wherein the seal has a circular cross section and, in particular, represents a fuse seal.  
     
     
         9 . The lamp as claimed in  claim 1 , wherein the outer bulb is kept air-tight by a sealing ring being introduced in the contact region between the sheet-metal part and the end of the open tube.  
     
     
         10 . The lamp as claimed in  claim 1 , wherein the inner vessel is sealed at two mutually opposing ends by means of identical seals, the outer bulb being fixed to the seals of the inner vessel by means of two sheet-metal parts.  
     
     
         11 . A method for producing a lamp having an outer bulb as claimed in  claim 1 , wherein an open tube is pushed centrally over an inner vessel, and then a sheet-metal part is placed onto the open end of the tube, the lugs being bent back through approximately 90°, and the central opening being selected to be slightly smaller than the cross section of the associated seal, with the result that, when it is placed on the seal, the central opening is enlarged to the diameter of the seal by the individual tabs of the surrounding zone being bent out slightly from the plane of the sheet-metal part.