Abstract: A hydraulic control and driving apparatus for a self-propelled artillery piece includes hydrostatic transmissions for the driving wheels which are driven by hydraulic motors and variable displacement hydraulic pumps. The apparatus includes means for training, elevating and firing the artillery piece by diverting hydraulic fluid from one main pump to the appropriate control elements.

Abstract: The present invention relates to an apparatus providing for the co-ordinated driving of a towing vehicle and a towed vehicle equipped with a hydrostatic driving system of its own. The respective driving wheels of the towed vehicle are each driven by a separate hydrostatic transmission and a variable output hydraulic pump coupled to a hydraulic motor which can be driven by output of said hydraulic pump and can be engaged with a driving wheel. The apparatus includes for each respective transmission control circuits having a control device mounted on the towing vehicle. The invention is particularly useful for a cross-country towing vehicle and a towed vehicle in the form of a heavy field artillery gun which for purposes of operating the hydrostatic transmissions is equipped with a reciprocating engine, for instance a gasoline engine, which actuates said transmissions via a dividing gear box.