Patent ID: 9725885
Date: 2017-08-08
CPC Classifications: E02F,F15B

Claim:
1. A hydraulic construction machine comprising: first and second hydraulic pumps; a traveling motor and a swing motor, which are operated by hydraulic fluid supplied from the first hydraulic pump; one or more hydraulic actuators, which are operated by hydraulic fluid supplied from the second hydraulic pump; a main control valve including first control valves configured to control a flow direction of the hydraulic fluid supplied from the first hydraulic pump to the traveling motor a first control valve installed on the most upstream side of a supply flow path of the second hydraulic pump and configured to be shifted to supply the hydraulic fluid from the first hydraulic pump to the traveling motor and to supply the hydraulic fluid from the second hydraulic pump to the swing motor in response to a control signal that is applied thereto when the traveling motor and the swing motor are simultaneously operated; a second control valve installed on the most downstream side of the supply flow path of the second hydraulic pump and configured to be shifted to close an opening of the most downstream side of the supply flow path of the second hydraulic pump in response to the control signal that is applied thereto when the traveling motor a controller configured to receive a detected manipulation signal from a sensing means that senses the traveling and swing operations; and an electronic proportional valve configured to output a control signal, which is generated to correspond to an electrical control signal output from the controller, to the first control valve and the second control valve to shift the first control valve and the second control valve when it is determined that a combined operation is performed in which the traveling motor and the swing motor are operated based on the manipulation signal input to the controller from the sensing means.