Patent ID: 7356991
Filing Date: 2008-04-15
Classification: E02F,F15B

Abstract:
1. A hydraulic control device of an excavator comprising a first hydraulic pump ( 1 ), a second hydraulic pump ( 2 ), a swing control valve ( 6 ) in fluid communication with the first hydraulic pump ( 1 ) for controlling hydraulic flow from the first hydraulic pump ( 1 ) to a swing motor ( 14 ), a boom high-speed control valve ( 7 ) disposed at downstream of the swing control valve ( 6 ) and in fluid communication with the first hydraulic pump ( 1 ) via a pressured fluid supply line ( 8 ) for controlling hydraulic flow from the first hydraulic pump ( 1 ) to boom cylinders ( 15 ), and a boom low-speed control valve ( 11 ) for controlling hydraulic flow from the second hydraulic pump ( 2 ) to the boom cylinders ( 15 ), further comprising: a working-on-slope detecting means ( a swing priority valve (