Hydraulic driving method of and hydraulic driving apparatus for hydraulic machine

A hydraulic driving apparatus for a hydraulic machine having a plurality of hydraulic actuators driven by a common hydraulic source, a corresponding plurality of control valves for controlling at least the flow rate of hydraulic fluid supplied to the plurality of hydraulic actuators from the common hydraulic source, and a corresponding plurality of operating-lever means for outputting operational signals for operating the respective control valves, comprising:

• operational-mode switching command means for outputting a switching command signal for altering an operational mode of at least one of the hydraulic actuators between a first operational-speed mode and a second operational-speed mode that is relatively slower than the first operational-speed mode;
• second-mode setting command means for outputting a setting command signal for setting the second mode of at least one of the plurality of hydraulic actuators;
• and
• control means for controlling the hydraulic actuators responsive to the operational signals outputted from the operational-lever means, the switching command signal outputted from said operational-mode switching command means and the setting command signal outputted from said second-mode setting command means;
• said control means including means for selecting at least one of the plurality of hydraulic actuators and for setting the second mode for the selected hydraulic actuators on the basis of a combination of the setting command signal and the operational signals outputted from the operational-lever means corresponding to the selected actuators;
• and said control means further including means for outputting control signals to the corresponding control valves for operating the non-selected hydraulic actuators in said first mode.

A hydraulic machine driving method for altering an operational-speed mode of a plurality of hydraulic actuators driven by a common hydraulic source in accordance with an operational-speed command signal, comprising the steps of:

• selecting arbitrarily at least one of the plurality of hydraulic actuators to alter an operational-speed mode of the selected actuators;
• altering an operational-speed command signal quantity for the selected hydraulic actuators into a quantity corresponding to a relatively slow operational-speed mode without altering the operational-speed modes of non-selected hydraulic actuators, by operating operating-lever devices for the selected hydraulic actuators;
• setting said altered operational-speed modes of said hydraulic actuators;
• and
• operating said hydraulic actuators according to said set operational-speed mode responsive to the operation of said operating-lever devices corresponding to said hydraulic actuators in which said altered operational-speed mode is set.