Patents Assigned to Kolbelco Construction Machinery Co., Ltd.
  • Patent number: 6648303
    Abstract: A winding-down side pilot port of a control valve is of a 2-port construction comprising a normal winding-down side port having a large pressure receiving area and a free fall side port having a small pressure receiving area, wherein in the free fall operation carried out by setting a motor to a small capacity, a pilot pressure of a winding-down side remote control valve is supplied to the free fall side port through a mode switching valve. Thereby, a stroke of the control valve can be suppressed so that a speed of a motor does not exceed an allowable speed.
    Type: Grant
    Filed: November 2, 2000
    Date of Patent: November 18, 2003
    Assignee: Kolbelco Construction Machinery Co., Ltd.
    Inventors: Yoshio Nishimoto, Takahiro Kobayashi, Taisuke Tsunoo, Etsujiro Imanishi, Satoshi Yonezawa