neurotensin and enkephalin injections into the ventral tegmental area: comparative study on dopamine

An excavating and loading system is disclosed which includes a vehicle with an excavating wheel assembly at the front and a plurality of conveyors toward the rear. The excavating wheel assembly comprises three excavating wheels having an overall width in excess of that of the remainder of the system. Each excavating wheel includes a plurality of digging buckets each comprising a wall supported for pivotal movement between a material receiving position and a material dumping position. The excavating wheel assembly is supported for vertical movement to vary the grade angle of the excavating made by the system, and a moldboard is linked to the excavating wheel assembly for movement therewith. Hydraulic cylinders may be utilized to vary the wheel assembly support provided by the moldboard in accordance with the material being excavated. The conveyors of the excavating and loading system include cross conveyors and a main conveyor for receiving material from the excavating wheels. The main conveyor transports the material rearwardly from the excavating wheel assembly and delivers the material to the opposite end of the vehicle. An auxiliary conveyor assembly is detachably supported at the opposite end of the vehicle to receive material from the main conveyor and to transport the material either laterally or rearwardly. The rear portion of the main conveyor is adapted to fold under the auxiliary conveyor assembly to reduce the overall height of the excavating and loading system during travel. The auxiliary conveyor assembly has a pair of conveyors mounted with the discharge end of one conveyor adjacent the receiving end of the other conveyor. The conveyors are mounted so that the relative attitude of the conveyors with respect to each other can be adjusted. Also, the conveyors can be selectivey positioned to discharge material from the end of either conveyor. A variably positionable deflector plate is provided to direct the discharge of material.