(19)
(11) EP 0 549 368 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
16.02.1994 Bulletin 1994/07

(43) Date of publication A2:
30.06.1993 Bulletin 1993/26

(21) Application number: 92311818.6

(22) Date of filing: 24.12.1992
(51) International Patent Classification (IPC)5: H01T 13/39, H01T 21/02
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 27.12.1991 JP 346901/91
07.05.1992 JP 114809/92

(71) Applicant: NGK SPARK PLUG CO., LTD
Nagoya-shi (JP)

(72) Inventors:
  • Matsutani, Wataru
    Nagoya-shi (JP)
  • Kagawa, Junichi
    Nagoya-shi (JP)

(74) Representative: Senior, Alan Murray 
J.A. KEMP & CO., 14 South Square, Gray's Inn
London WC1R 5LX
London WC1R 5LX (GB)


(56) References cited: : 
   
       


    (54) An electrode for a spark plug and a method of manufacturing the same


    (57) In an electrode for a spark plug, a composite column is provided to have a beat-conductor core embedded in a metallic clad by means of swaging. A firing tip is provided from a slug which is made of a noble metal. The slug is concentrically placed on an end surface of the metallic clad, and a laser beam welding is applied on the slug to thermally melt whole the slug 80 that the end surface of the metallic clad is partly fused into the slug in the range of 0.5 wt % to 80.0 wt %.






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