| 摘要 |
A hydraulic control system is disclosed for a hydrostatically operated earth-working machine which automatically adjusts the travel speed of the machine in response to the load conditions being encountered by an attached powered implement. The system includes a control cylinder which is connected into the hydraulic circuit that powers the implement to sense changes in hydraulic pressure due to increased or decreased loads on the implement. Hydraulic pressure in the implement circuit extends the control cylinder piston when the implement is under load. An adjustable spring mechanism reacts against the rod end of the piston to keep the piston retracted in the cylinder when there is no load on the implement. A control link is pivotally mounted to the piston rod free end for selective connection to the ground drive control of the machine. The pivotal control link is only engageable with the ground drive control when the piston rod has been extended a pre-determined distance, which corresponds to optimum engine output, against the resistance of the spring mechanism. After the control link is locked into engagement with the ground drive control, pressure changes in the implement hydraulic circuit, due to increased or decreased load on the implement, cause corresponding linear back and forth movement of the piston rod which is transmitted by the control link to the ground drive control. This action automatically adjusts the ground speed of the mechanism in response to the load being encountered by the implement and thereby maintains a constant engine output.
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