(19)
(11) EP 0 627 543 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
02.08.1995 Bulletin 1995/31

(43) Date of publication A2:
07.12.1994 Bulletin 1994/49

(21) Application number: 94303286.2

(22) Date of filing: 06.05.1994
(51) International Patent Classification (IPC)5: E21B 4/14, E21B 21/02, E21B 21/14
(84) Designated Contracting States:
CH DE FR GB IT LI NL

(30) Priority: 01.06.1993 KR 9401593

(71) Applicants:
  • KENCHO KOBE CO., LTD.
    Osaka-shi, Osaka-fu (JP)
  • Mo, Jeon Jin
    Song-pa Gu, Seoul (KR)

(72) Inventor:
  • Mo, Jeon Jin
    Song-pa Gu, Seoul (KR)

(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) Underground borer with down hammer


    (57) In an underground borer with down hammer having a vehicle body 1. a guide stilt 2 standing on the vehicle body, and a rotary machine 4 having its bottom coupled with a screw shaft 3 and a down hammer B. a supply unit 5 is interposed between the rotary machine 4 and the screw shaft 3, a fluid conduit 6 is formed centrally of the screw shaft 3, compressed air conduits 7 and 7' are formed to surround the fluid conduit 6. and a fluid jetting pipe 8 is arranged centrally of the down hammer B to extend until the inside of a bit body 9 so that water may be discharged, along with high-pressure compressed air, from a central portion of the bottom surface of the bit body during boring to cool the bit body, promote anti-wear properties, suppress powdery dirts, reduce noises and increase the boring speed.






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