(19)
(11) EP 0 276 845 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
18.10.1989 Bulletin 1989/42

(43) Date of publication A2:
03.08.1988 Bulletin 1988/31

(21) Application number: 88101219.9

(22) Date of filing: 28.01.1988
(51) International Patent Classification (IPC)4E02D 7/18
(84) Designated Contracting States:
CH DE FR GB IT LI NL

(30) Priority: 30.01.1987 JP 20128/87

(71) Applicant: KABUSHIKI KAISHA TAKAHASHI ENGINEERING
Tokyo (JP)

(72) Inventors:
  • Tasaki, Yasuo
    Edogawa-ku, Tokyo (JP)
  • Kumai, Seizo
    Kita-ku, Tokyo (JP)

(74) Representative: Huss, Carl-Hans, Dipl.-Ing. 
Patentanwalt, Postfach 14 54
D-82454 Garmisch-Partenkirchen
D-82454 Garmisch-Partenkirchen (DE)


(56) References cited: : 
   
       


    (54) Pile driver


    (57) The present invention provides a pile driver com­prising a vibration cylinder (3) and a self-equilibration cylinder (7) so provided vertically in series with each other that the axes of their respective rods lie on the center line passing through the center of gravity of an inertial weight (1), the rods of the vibration and self-equilibration cylinders being coupled to each other, the vibration cylinder having provided therein a changeover valve (10) to supply and discharge a pressurized fluid to and from the vibration cylinder, the self-equilibration cylinder having provided therein a control valve (11) responsive to the rod of either the self-equilibration cylinder or vibration cylin­der to supply and discharge the pressurized fluid to and from a control chamber in the self-equilibration cylinder. The piston of the self-equilibration cylinder is supported with a low rigidity to the inertial weight by means of accumulators (14) provided as communicating with the control chambers in the self-equilibration cylinder, and also the self-equilibration cylinder or vibration cylinder has pro­vided at the lower end of the rod thereof a chuck (17) which grasps the pile.







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