Patent Publication Number: US-6992560-B2

Title: Fuse structure

Description:
FIELD OF THE INVENTION 
   The present invention relates to a fuse structure, which is provided with an aperture on its non-conductive tube in order to facilitate in manufacturing without flaws. 
   BACKGROUND OF THE INVENTION 
   A conventional fuse includes a non-conductive tube ( 1 ), as shown in  FIG. 1A , which connects one end with a metal cap ( 3 ) by welding with tin ( 2 ). A resistance filament ( 4 ) is provided therein. And then, another cap ( 3 ′) is welded on the other end of the non-conductive tube ( 1 ) with tin ( 2 ′) to produce a complete fuse, as in  FIGS. 1B and 1C . In such manufacturing procedure, when the cap ( 3 ′) is being welded, the temperature will increase and cause air in the tube ( 1 ) to expand and be pushed outwardly. The tin ( 2 ′) is usually extruded and exposed outside the metal cap ( 3 ′) as in  FIG. 1D . This fuse is useless and is only a defeat work. 
   SUMMARY OF THE INVENTION 
   The present invention is to provide a fuse structure, which can overcome the drawback of prior art and provides a perfect product. 
   Now, accompanying with the following drawings, the character of the present invention will be described here and after. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1A to 1D  are cross-sectional plan view showing a conventional fuse in manufacturing procedures. 
       FIG. 2  is an exploded perspective view showing a fuse structure according to the present invention. 
       FIG. 3  is an assembled perspective view of  FIG. 2 . 
       FIG. 4  is a cross-sectional plan view of  FIG. 3 . 
       FIGS. 5A to 5D  are cross-sectional plan view showing the fuse structure in manufacturing procedures according to the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Please referring to  FIGS. 2 to 4 , the fuse structure of the present invention includes a non-conductive tube ( 1 ), which connects both ends with two respective metal caps ( 3 ), ( 3 ′) by welding tin ( 2 ), ( 2 ′). An inner resistance filament ( 4 ) is provided in the tube ( 1 ) connecting with two caps ( 3 ), ( 3 ′). The improvement of the present invention is to provide an aperture ( 11 ) on the non-conductive tube ( 1 ). The aperture ( 11 ), which can be covered by the cap ( 3 ′) when it is a complete product, will be better. 
   In manufacturing procedures, as showing in  FIGS. 5A to 5D , it can be found that heated air in the tube ( 1 ) can be exhausted through the aperture ( 11 ) when the cap ( 3 ′) is welded on the tube ( 1 ). Hence, tin ( 2 ′) will never be extruded outside the cap ( 3 ′) and a perfect fuse is manufactured. 
   Accordingly, the fuse structure of the present invention can be manufactured is ease and the complete product will be flawless that reaches the purpose of patent.