Patent GB-724354-A (GB)
Title: Improvements in or relating to pistons
Inventor: HOLT GEORGE ALLEN
IPC: F01P3/08
Filed: 1953-05-22
Abstract: 724,354. Pistons. RICARDO & CO. ENGINEERS (1927), Ltd. May 22,1953, No. 14437/53. Class 122 (1). A trunk piston comprising a skirt A<SP>3</SP> carrying the gudgeon-pin bosses A<SP>4</SP> and a circumferentially-extending trough A<SP>5</SP> which has its inner edge closer to the crown A<SP>1</SP> than its outer edge and is constituted by a lip F<SP>3</SP> separated from the crown by a gap for the delivery of oil in one or more jets from the connecting-rod D<SP>1</SP> during reciprocation of the piston so that a volume of oil is maintained and shaken back and forth in the space between the trough and the crown, has a baffle plate F<SP>5</SP> for preventing or restricting the escape of oil from the space between the trough and the crown, the plate F<SP>5</SP> being supported beneath the underside of the crown A<SP>1</SP> from the inner edge of the trough by supports F<SP>4</SP> past which the oil is directed into the trough. A circular base F<SP>1</SP> supports the rim F<SP>3</SP> and is secured by bolts F to a wall E<SP>1</SP> of the trough. The arrangement is such that the quantity of oil fed through a passage D<SP>4</SP> in the connecting- rod D<SP>1</SP> during each reciprocation of the piston is sufficient to replace the volume discharged through an opening F<SP>2</SP> bounded by the lip F<SP>3</SP>. This volume is that above the opening and lying between the level G<SP>1</SP> and the baffie-plate F<SP>5</SP> when the piston is at the start of a return stroke. The quantity of oil discharged may be varied by changing the distance between the baffle plate F<SP>5</SP> and the crown A<SP>1</SP> or by modifying the size of the plate, so that it does not completely cover the opening F2, or both. In a modification, Fig. 4, two passages O are provided for discharging oil from the trough H<SP>4</SP> and the arrangement is such that the passages open into the trough at a level P which keeps the quantity of oil between the trough and the head H<SP>1</SP> less than that required to cover the head of the piston to a depth extending to the baffle N<SP>5</SP> when the piston is on a return stroke. One, or more than two passages O may be provided and they may open into the interior of the piston. When used with a horizontal cylinder, the passage or passages O are preferably arranged in the lowermost part of the piston so that during slow-running the oil may be ejected directly out of the cylinder bore. This may be facilitated by the use of pipes beyond the skirt H<SP>3</SP>. The oil may be discharged into a trough or on to a part which it is desirable to lubricate. In other arrangements, instead of the oil ejected passing through the opening bounded by the lip from a position against the baffle plate or through the passages O, a combination of the two systems may be used, or an arrangement in which a quantity is ejected from a position against the baffle and the rest over the lip. Also, the arrangement may be such that the space between the trough and the head of the piston is substantially full of oil, ejection occurring towards the end of each out-stroke and at the beginning of the in-stroke. Specification 617,224 is referred to.