Allis-chalmers Corporation

Ronald E Spooner

Terry R Downing

A detachable cover member for use with a reservoir for hydraulic fluid such as oil in which the various components associated with the reservoir are rigidly mounted on the cover member and are removed from the reservoir tank when the cover is removed. Thus, the suction conduit and the return conduit extend through and are both rigidly secured, as by welding, to the detachable cover member. The respective suction and return conduits are adapted to extend down into the interior of the reservoir tank when the cover member is secured in overlying relation to the cover-receiving opening of the reservoir. A baffle member is rigidly secured to the normally inner surface of the cover member in a plane substantially perpendicular to the inner surface of the cover to divide the interior of the reservoir into suction and return chambers, the baffle being so constructed as to permit fluid communication between the two chambers. Each of the respective suction and return conduits extends from its respective rigid connection to the cover member through the baffle member, each respective conduit being rigidly connected as by welding to the baffle to provide a reinforced construction for the cover subassembly. A ' breather' device is rigidly mounted on the normally outer surface of the cover member and is in gaseous communication with the interior of the upper end of the reservoir to maintain atmospheric pressure above the liquid level in the reservoir tank. A combined fill tube and dip stick holder are also rigidly mounted on the detachable cover member. Thus, when the detachable cover member is removed from the reservoir, all of the aforementioned components are removed along with the cover.

Removable reservoir cover having internal parts of reservoir mounted

When the load moment on a counterbalanced lift truck exceeds a predetermined magnitude, a blocking valve automatically prevents forward tilting of the mast and elevation of the load. The load moment is sensed by the pressure differential across the tilt jack and the blocking valve is actuated by the pressure differential. In order to prevent the blocking valve from becoming locked up, when the tilt jack is contracted to the end of its stroke, a spring-biased unloading valve is incorporated in the tilt jack piston. Abuse of the truck is reduced and operator safety is improved further by the provision of a second blocking valve which prevents lifting loads when the tilt jack is at the end of its extension stroke, that is when the mast is tilted forwardly as far as permitted by the tilt jack. In this condition the second blocking valve will close preventing further raising of the load. However, retraction of the tilt and lift jacks is permitted even though the blocking valves are in their closed positions. The second blocking valve is biased toward its open position by the pressure in the rod end of the tilt jack and toward its closed position by the pressure in the lift jack. The blocking valves are biased toward their open positions by adjustable spring means which permit the control system to be adjusted to meet the protection requirements of lift trucks with different load carrying capacities. Pressure modulating restrictors are provided in pilot lines to the blocking valves to prevent false actuation when pressure fluctuations occur.

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Richton Park, IL, United States of America

Ronald E Spooner