Internal oil seal for piston

Claim 1

In a hollow piston and connecting rod assembly for use in an internal combustion engine wherein the piston includes a head, a cylindrical skirt extending from the head and a pair of diametrically opposed, transverse bores extending through the skirt of the piston, wherein a connecting rod has a passageway therethrough for passage of lubricant and a bulbous portion at one end through which an annular bore extends, wherein a wrist pin extends through the bore of the connecting rod and is supported in the diametrically opposed bores of the piston, wherein inner bushing means are inserted in the bore of the connecting rod and around the wrist pin, providing a bearing surface between the inner surface of the bushing means and the wrist pin, wherein outer bushings, spaced from the terminating ends of the inner bushing means, are inserted in the bores extending through the skirt of the piston and around the wrist pin to provide a bearing surface between inner surfaces of the outer bushings and the wrist pin, the spaces between the inner and outer bushings providing lubricant passages so that lubricant forced under pressure through the passageway in the connecting rod lubricates the wrist pin and cools the piston head, the improvement comprising: sealing means, including (1) segments on each side of the wrist pin conforming to the interior surface of the skirt of the piston and extending upwardly along the interior of the skirt to a point laterally of the axis of the wrist pin and then laterally towards the wrist pin, (2) a groove formed in the portion of each segment facing the wrist pin, and (3) a wiping seal received in each of the grooves contacting the exterior surface of the bulbous portion of the connecting rod, the segments and wiping seals closing the entire area between the bulbous portion of the connecting rod and the interior surface of the piston, the sealing means sealing the entire area between the bulbous portion of the connecting rod and the inner walls of the skirt so that lubricant forced through the passageway in the connecting rod into a hollow space beneath the piston head and above the connecting rod builds up pressure therein, the lubricant forced to return below the sealing means substantially only along the bearing surfaces between the inner and outer bushings and wrist pin to provide continuous lubrication thereto.