(19)
(11) EP 1 172 325 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
17.04.2002 Bulletin 2002/16

(43) Date of publication A2:
16.01.2002 Bulletin 2002/03

(21) Application number: 01302982.2

(22) Date of filing: 29.03.2001
(51) International Patent Classification (IPC)7: B66D 1/44, B66D 1/48, B66D 1/08, F15B 13/04, F15B 13/042, F15B 11/042, F15B 11/12
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 13.07.2000 JP 2000212746
01.02.2001 JP 2001025132

(71) Applicant: KOBELCO CONSTRUCTION MACHINERY CO., LTD.
Hiroshima-shi, Hiroshima 731-0138 (JP)

(72) Inventors:
  • Nishimoto, Yoshio, Nabco Seishin Plant
    Kobe-shi, Hyogo 651-2413 (JP)
  • Kobaysahi, Takahiro, Okubo Plant
    Okubo-cho, Akashi-shi, Hyogo 674-0063 (JP)
  • Tsunoo, Taisuke, Okubo Plant
    Okubo-cho, Akashi-shi, Hyogo 674-0063 (JP)
  • Imanishi, Etsujiro, Kobe Corporate Research Labs.
    Nishi-ku, Kobe-shi, Hyogo 651-2271 (JP)
  • Yonezawa, Satoshi, Kobe Corporate Research Labs.
    Nishi-ku, Kobe-shi, Hyogo 651-2271 (JP)

(74) Representative: Bailey, David Martin 
Brookes Batchellor 102-108 Clerkenwell Road
London EC1m 5SA
London EC1m 5SA (GB)

   


(54) Control device for hydraulic drive winch


(57) A winding-down side pilot port (5b) of a control valve (5) is of a 2-port construction comprising a normal winding-down side port (5b1) having a large pressure receiving area and a free fall side port (5b2) having a small pressure receiving area, wherein in the free fall operation carried out by setting a motor (2) to a small capacity, a pilot pressure of a winding-down side remote control valve (8) is supplied to the free fall side port through a mode switching valve (22). Thereby, a stroke of the control valve (5) can be suppressed so that a speed of a motor (2) does not exceed an allowable speed.
Additionally a load holding hydraulic system is disclosed with a hydraulic motor (101) and bidirectional pump (104) in closed circuit.






Search report