Abstract: A linear excavation control apparatus for a hydraulic power shovel has a laser oscillator installed on the surface of a target area of excavation, a laser beam receiving unit mounted upon a vehicle body of the hydraulic power shovel and a controller for controlling an attitude of excavation by a bucket. The inclination of the laser beam receiving unit and the attitude of excavation of the bucket can be adjusted.

Abstract: A control device for hydraulically operated machines for carrying out control to move a working unit with priority over other working units. A weight is added to each of the same manipulated amount of a plurality of operation levers 3, 4 in association with work type of M1 to M5 and the weights are stored in a memory of a controller 5 in association with the type of the operation levers 3, 4 and the work type. The work type M1 to M5 are selected by a switch 2. When the operation lever 3, 4 is manipulated and a work type is selected by the switch 2, the weight associated with the type of the manipulated operation lever 3, 4 and the selected work type M1 to M2 is read from the memory, and the read weight is added to a manipulated amount S1, S2 of the manipulated operation lever 3, 4. Then, not signals indicative of the manipulated amount S1, S2 of the operation lever 3, 4 but signals E, E' added with the weight which are indicative of the manipulated amount are outputted to control valves 7.

Abstract: A hydraulic oil volume change-over control apparatus for a hydraulic excavator subjects a hydraulic pump to load sensing control so as to set an optimum volume of hydraulic oil while an engine for driving the hydraulic pump is operated at a rotational speed at which the fuel consumption of the engine is minimum, by setting a low power mode during breaker work or the like which is performed with a smaller volume of hydraulic oil than that needed during normal excavating work.