Abstract: A prefinished piston pin insert bearing wherein the radial clearances required for acceptable bearing function are maintained in spite of the tolerance required for assembly through a combination of inner bearing surface geometry and related structure for retaining the bearing against axial and rotational movement. The interior bearing geometry is formed of radii equal to that of the piston pin which are offset vertically into the upper and lower bearings to generate a load bearing surface thereon and of radii offset horizontally and of sufficient length to provide assembly clearance for the piston pin and a load bearing surface of approximately 120.degree. to 150.degree.. The bearings are retained against movement through connections with the piston head, the piston skirt, and between the various bearing pieces. Means are also provided for feeding oil under pressure to the piston pin and bearing interface for lubrication and to the piston assembly for cooling.

Abstract: A novel prefinished piston pin insert bearing is described wherein the tight radial clearances required for acceptable bearing function are maintained in spite of the tolerances required for assembly through a unique inner bearing surface geometry and through a unique methodology of bearing retention against axial and rotational movement. The interior bearing geometry is formed of radii equal to that of the piston pin which are offset vertically into the upper and lower bearings and of radii of nonspecific size which are offset horizontally. The bearings are retained against movement through connections with the piston head, the piston skirt, and between the various bearing pieces. Means are also provided for feeding oil under pressure to the piston pin and bearing interface for lubrication and to the piston assembly for cooling.

Abstract: A foundry core is disclosed for molding a cast blank machinable to produce a crosshead piston head member. The core shapes an exterior surface region of the blank section corresponding to the ring belt in the machined product. The core-shaped exterior surface provides a readily accessible reference for accurately positioning the core during subsequent machining operations.