A piston-crankshaft connector for an internal combustion engine can comprise a main connecting rod connected with its big end bore to a crankpin and at least one auxiliary connecting rod connected to off-axial surfaces made on the crankpin. On the piston side, the at least one auxiliary connecting rod can be attached to an upper crankpin nested within the main connecting rod, where the crankpin carries off-centred piston pin bore. Such construction can modify a piston pin bore distance relative to a main journal central axis during their rotation, which can improve the internal combustion stroke-to-stroke performance. A compression ratio can additionally or alternatively be adjusted by hydraulics acting on an entire segmented eccentric ring relative position within connecting rod bearing space via crankpin oil channels.

A piston-crankshaft connector for an internal combustion engine can comprise a main connecting rod connected with its big end bore to a crankpin and at least one auxiliary connecting rod connected to off-axial surfaces made on the crankpin. On the piston side, the at least one auxiliary connecting rod can be attached to an upper crankpin nested within the main connecting rod, where the crankpin carries off-centred piston pin bore. Such construction can modify a piston pin bore distance relative to a main journal central axis during their rotation, which can improve the internal combustion stroke-to-stroke performance. A compression ratio can additionally or alternatively be adjusted by hydraulics acting on an entire segmented eccentric ring relative position within connecting rod bearing space via crankpin oil channels.

A fastener driving tool with a working cylinder and a piston, the piston outer surface having a lubricant-saturated foam material that stores and dispenses lubricant into the piston-cylinder wall interface, thereby increasing the performance and lifespan of the tool. Another embodiment discloses a two-part piston in which the bottom portion is made of metal and absorbs the main mechanical loading forces of the piston drive and return strokes, and the top portion is made of a non-metallic material that has surfaces that act as sliding bearings against the inner wall of the cylinder.

A fastener driving tool with a working cylinder and a piston, the piston outer surface having a lubricant-saturated foam material that stores and dispenses lubricant into the piston-cylinder wall interface, thereby increasing the performance and lifespan of the tool. Another embodiment discloses a two-part piston in which the bottom portion is made of metal and absorbs the main mechanical loading forces of the piston drive and return strokes, and the top portion is made of a non-metallic material that has surfaces that act as sliding bearings against the inner wall of the cylinder.

In a piston including a plurality of piston rings, a state where a difference in differential pressure between the piston rings is eased is maintained even after passage of time, and the life of the piston rings is extended.

A piston includes a piston body in which a plurality of ring grooves is formed, and a plurality of piston rings respectively arranged in the ring grooves. In the piston, a leakage groove is formed on a low-pressure side surface of the ring groove, and in a state where the piston ring is abutted with the low-pressure side surface while being abutted with a cylinder, the leakage groove ensures communication between a high-pressure side space and a low-pressure side space with respect to the piston ring.

In a piston including a plurality of piston rings, a state where a difference in differential pressure between the piston rings is eased is maintained even after passage of time, and the life of the piston rings is extended.

A piston includes a piston body in which a plurality of ring grooves is formed, and a plurality of piston rings respectively arranged in the ring grooves. In the piston, a leakage groove is formed on a low-pressure side surface of the ring groove, and in a state where the piston ring is abutted with the low-pressure side surface while being abutted with a cylinder, the leakage groove ensures communication between a high-pressure side space and a low-pressure side space with respect to the piston ring.

The present invention refers to a piston for an internal combustion engine, particularly a V-engine. The piston comprises an oil drainage groove provided in the outer circumferential surface of the piston between a ring belt and a piston skirt of the piston, the piston skirt being provided with two recessed pin boss portions on opposed sides of the piston, wherein the piston skirt is further provided with at least one oil drainage duct arranged between the two recessed pin boss portions at an outer surface of the piston skirt and configured to fluid-communicatively connect the oil drainage groove with the recessed pin boss portions.

The present invention refers to a piston for an internal combustion engine, particularly a V-engine. The piston comprises an oil drainage groove provided in the outer circumferential surface of the piston between a ring belt and a piston skirt of the piston, the piston skirt being provided with two recessed pin boss portions on opposed sides of the piston, wherein the piston skirt is further provided with at least one oil drainage duct arranged between the two recessed pin boss portions at an outer surface of the piston skirt and configured to fluid-communicatively connect the oil drainage groove with the recessed pin boss portions.

Systems and methods include providing an aircraft with a fuselage and a wing assembly rotatable relative to the fuselage about a stow axis between a flight position and a stowed position. The aircraft includes an engine reduction gearbox having a retractable driveshaft that selectively engages the mid-wing gearbox via axially translatable motion along a rotation axis when the wing assembly is in the flight position. The mid-wing gearbox includes a plunger seal that is displaced in response to contact with the retractable driveshaft. Displacement of the plunger seal allows lubricant to flow through an inner bore in the retractable driveshaft, across splines of the retractable driveshaft and the mid-wing gearbox, and through lubrication ports in the mid-wing gearbox to lubricate the engine reduction gearbox, splines of the retractable driveshaft and the mid-wing gearbox, and the mid-wing gearbox via a single lubrication system.

A ringset is configured to be arranged on a piston for sealing a gas in a high-pressure region of a cylinder in the absence of oil or other liquid lubricant. The ringset includes one or more rings made from a high-strength material as a sealing element. The ringset also includes a solid lubricant applicator configured to provide lubrication between the one or more rings and a bore of the cylinder. For example, the ring can support pressure loads from high-pressure gas without breaking, while the applicator need not act as a seal. As the piston reciprocates in the bore, the applicator slides against the bore and applies solid lubricant material to the bore, resulting in a solid lubricant film on the bore against which the sealing element may slide. The applicator includes a material such as a graphite, a polymer, or other suitable solid lubricant.