Abstract: A unitary housing for a hydraulic unit such as tandem pump, having a plurality of rotating groups driven in one direction about a common axis by a source of rotary power having a pair of opposite end walls generally transverse to the common axis, a continuous side wall connecting the end walls, and at least two apertures in the side wall which allow the insertion of a rotating group into the housing. The housing can also include a first flange on one of the end walls for mounting the housing to a source of rotary power. A second flange can be included on the other end wall for mounting an auxiliary pump to the main hydraulic unit. Alternatively, if the second flange is the same size as the first flange, the housing allows the user to change the rotation of the tandem pump by spinning the housing end-for-end and without changing any internal components.

Abstract: A carriage assembly, 20h for a lift truck upright assembly, 12, has pivotally mounted forks, 30, controlled by hydraulic cylinders, 36, that are operated by side shifter circuit, 110, having a single operator control, 124, for manipulating the forks in unison, opening or closing the forks, or shifting them right or left in a coordinated fashion.

Abstract: A housing for hydraulic units includes a single cast unitary hollow housing having a continuous side wall extending between opposing forward and rearward walls to form an enclosed housing. Preferably, the continuous side wall includes opposing top and bottom walls, and opposing right and left side walls. A rotary axis is located between the forward and rearward walls, and is generally centered in an opening formed in the forward wall. Access openings are provided in the continuous side wall, transverse to the rotary axis, for installation of components within the housing during assembly.

Abstract: An automotive control system for hydrostatic pumps includes a hydraulic circuit with an automotive orifice located upstream of the main hydrostatic loop with replenishing check valves and downstream of the fill pump. The location of the automotive orifice upstream of the check valves isolates system leakage from affecting flow to the automotive orifice. A hydrostatic unit displacement control valve has a drain side connected to the hydraulic circuit downstream of the fill pump and in parallel with the automotive orifice, and has a supply side connected downstream of the automotive control orifice. The input logic of the control valve is reversed to compensate for the greater pressure available to the drain side of the control valve as compared to the supply side. Reversing the input logic of the control valve provides servo control pressures without the need to isolate the control supply from the hydrostatic loop supply.