Excavating – Ditcher – Condition responsive
Reexamination Certificate
2003-10-14
2009-12-29
Will, Thomas B (Department: 3671)
Excavating
Ditcher
Condition responsive
C060S446000, C037S195000
Reexamination Certificate
active
07637039
ABSTRACT:
A hydraulic pump displacement control apparatus for a working vehicle capable of reliably detecting the working vehicle under excavating operation and reducing loss in power is provided. For this purpose, the control apparatus includes a bottom pressure detector (45) for detecting a hydraulic pressure in a bottom side (13A) of a cylinder (60) for operating a working machine (10), a displacement control device (41) for controlling a displacement of a variable displacement hydraulic pump (26), and a controller (50) which determines that an excavating operation starts when a predetermined time elapses with a detection value from the bottom pressure detector at a predetermined value or less and thereafter, the detection value exceeds the predetermined value, and outputs a displacement control signal to reduce the displacement of the hydraulic pump to a predetermined displacement that is smaller than the maximum displacement to the displacement control device.
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A Spanish Search Report dated Apr. 1, 2008, issued in a counterpart Spanish Application.
Sato Yoshiharu
Toda Eiji
Frishauf Holtz Goodman & Chick P.C.
Komatsu Ltd.
McGowan Jamie L
Will Thomas B
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