Hydraulic pumps or motors of the rotating barrel type

Claim 1

In a hydraulic pump or motor having a fixed cylindrical casing provided with a bottom having a slide-face with first and second orifices formed therein; a barrel supported in said casing for rotation about an axis, said barrel having cylinders with slidable pistons therein; means for placing said cylinders alternately into communication with said first and second orifices of said slide-face; means for reciprocally moving said pistons in said cylinders and producing forces on said pistons having components acting as shearing forces applied to said barrel; a rotatable shaft; means connecting said barrel to said shaft for rotation therewith; a support coaxial with said shaft and rigidly secured to said casing; and a bearing inside said barrel between said support and said barrEl, said bearing being of small diameter and arranged at the point of application along the axis of said barrel of the resultant of the shearing forces applied to said pistons, so as to absorb said shearing forces, said means for reciprocally moving said pistons comprising a piston actuating plate to which said pistons are coupled and means permitting the regulation of the inclination of said plate with respect to the geometric axis of said shaft, said piston actuating plate comprising two convex cylindrical portions having a common axis and the same diameter, and arranged symmetrically with respect to the geometric axis of said shaft, two support elements for said cylindrical portions forming a recess having a shape complementary to that of said convex portions, said elements being rigidly fixed to said support to permit said piston actuating plate to thus pivot with respect to said support, an improvement wherein said piston actuating plate comprises at least one lateral bearing secured to one of the convex cylindrical portions of the piston actuating plate at one of the side faces thereof and facing an adjacent of said support elements to engage the same, when the piston actuating plate is subjected to transverse stresses urging the lateral bearing and said adjacent support element together.