Abstract: A control system for controlling the opening and closing of the tailgate of a dump truck includes an actuator unit which is mounted on the truck box or tailgate. The actuator unit controls the degree of opening of the tailgate during the unloading operation and therefore the rate at which the material is discharged from the truck box. A positional feedback unit produces an output signal indicating the movement of the tailgate between open and closed positions. This signal is displayed on a control panel of a control unit in the truck cab. An operator in the truck cab can therefore control opening and closing of the tailgate and can monitor the position of the tailgate. The control system effects an accurate metering of material from the truck box.

Abstract: A retractable mud flap assembly for a motor vehicle includes an enclosure having a forward end and a rearward end and a generally flat profile and being open at its rearward end. A mud flap of a flat flexible shape is positioned for retraction into the enclosure and extension therefrom. A linear actuator, which is preferably a double acting hydraulically or pneumatically actuated cylinder, is attached to the mud flap and adapted to apply force thereto to extend and retract them. Preferably a downwardly curved lip extends from the lowermost rear surface of the enclosure.