Abstract: As earth and sand are loaded on a dump truck by operating a loader, a quantity of load to be carried by the dump truck is stepwise increased at every time when a loading operation is performed. To assure that the load does not substantially exceed a rated load given to the dump truck, there is a need of estimating a load to be carried by the dump truck during a next loading operation. To this end, there is provided an apparatus for representing a load to be carried by the dump truck for which representing is effected on the basis of the load which has been measured using a load meter of the type mounted on the dump truck.

Abstract: A driving control device in a crawler type tractor comprises a lever capable of being operated in the forward or reverse (backward) direction and capable of being operated in the right or left direction when the lever is operated so as to move to the end of the forward or reverse direction, and a speed-stage command device capable of generating and transmitting commands for speed stages for the forward and the reverse directions. When a first sensor detects the lever operation in the forward or reverse direction; the transmission speed stages can be selected in accordance with the first sensor output and the output of the speedstage command device, and the operation amount of the lever in the right or left direction is detected by a second sensor so that steering clutches of the tractor can be controlled in accordance with the output of the second sensor.