Patent ID: 7069674
Filing Date: 2006-07-04
Classification: E02F

Abstract:
1. A hydraulic circuit for a backhoe, comprising: first, second and third pumps driven by an engine; left and right traveling unit valve sections configured to receive pressure oil from the first pump and the second pump independently of each other; a front implement valve section configured to receive combined pressure oil including oil discharged from a center oil passage of said left traveling unit valve section and oil discharged from a center oil passage of the right traveling unit valve section; a swiveling valve section configured to receive pressure oil from the third pump; and a parallel oil passage having a restrictor and disposed parallel to a center oil passage of said swiveling valve section; wherein said front implement valve section is configured to receive also pressure oil from the center oil passage of the swiveling valve section and the parallel oil passage; and there is provided a load sensing system for controlling flow amounts of the first and second pumps according to a hydraulic load generated in a front implement operation.