Abstract: Disclosed is a remote control system which produces electric signals to be sent to a governor driving device from an operator's cabin for remote control of the governor mechanism. This remote control system essentially includes a detector for detecting the amount of control effected to the governor mechanism, and a control device which operates on detection signals from the detector and operation signals from an operating device in the operator's cabin. The control device is adapted to produce a stop signal to the driving device when the difference in control amount between two cyclic time points becomes smaller than a predetermined value, which is regarded as a limit of operation of the governor mechanism, thereby preventing impairment or damages of the governor mechanism and operating device.

Abstract: A drive control system, which is suitable for use in a hydraulic machine, is equipped with an electric lever device having a manipulation lever and a potentiometer for generating an electrical manipulation signal corresponding to the degree of each manipulation of the lever, a control valve connected to a hydraulic circuit adapted to actuate a hydraulic actuator, and a controller unit equipped with a main controller for receiving the manipulation signal and computing a control signal for the control valve on the basis of the manipulation signal and an output device for generating an electrical actuation signal corresponding to the control signal.

Abstract: A control system for a hydraulic excavator having a prime mover, revolution number control device for the prime mover, at least one variable displacement hydraulic pump driven by the prime mover, displacement volume control device for the pump, actuators driven by pressurized fluid discharged from the pump and working elements driven by the respective actuators. The control system includes maximum revolution number altering device for the prime mover associated with the revolution number control device, maximum displacement volume altering device for the pump associated with the displacement volume control devices, devices for sensing the operation condition of the actuators, devices for selecting an operation mode for each working element and control devices.