GB722068A - Improvements in or relating to piston rings - Google Patents

Abstract

722,068. Piston packing. JONES, R. J. July 7, 1953 [Aug. 22, 1952], No. 21094/52. Class 122 (1). A compound piston-ring comprises an outer part, O, an inner part I and abutment faces I<SP>1</SP>, O<SP>1</SP>, I<SP>2</SP>, O<SP>2</SP> in the vicinity of a split in the part O to restrict expansion of that part. The abutment faces are provided by projections on the part O and oversize slots in the part I to receive the projections, the corners of the clearance faces I<SP>3</SP>, I<SP>4</SP> of the slots and those of the adjacent faces O<SP>3</SP>, O<SP>4</SP> of the projections being bevelled or rounded. Preferably expansion of the part I is also restricted by abutment faces I<SP>5</SP>, O<SP>5</SP>; I<SP>6</SP>, O<SP>6</SP> provided by further slots and projections arranged adjacent the split in the part I which is preferably disposed diametrically opposite that in the part O. The part I may be weakened by four recesses I<SP>7</SP>, I<SP>8</SP>, I<SP>9</SP>, I<SP>10</SP> preferably formed in its outer surface. In a modification, expansion of the inner part is not restricted by abutments adjacent its split and that of the outer part is restricted by oversize slots in the outer part which co-operate with projections on the inner part adjacent the split, the abutment and the clearance faces of the slots and projections being rounded or bevelled. Tapped holes are formed in the outer part to facilitate removal. The rings should preferably be accommodated in the two grooves in the piston nearest to the compression space or spaces and preferably half of the remaining rings should be removed. Under working conditions, the ring, which is of metal or alloy, is intended to bear very lightly in the bore. The proportions of the ring and its clearance in the bore are referred to.