Pistons are disclosed herein. An apparatus includes an actuator defining a first chamber; and a piston disposed in the first chamber, the piston including a second chamber and a seal groove in which a seal is disposed, the second chamber to receive fluid from the first chamber to enable a force imparted by the fluid within the second chamber to urge the seal into sealing engagement with a surface defining the first chamber.

Pistons are disclosed herein. An apparatus includes an actuator defining a first chamber; and a piston disposed in the first chamber, the piston including a second chamber and a seal groove in which a seal is disposed, the second chamber to receive fluid from the first chamber to enable a force imparted by the fluid within the second chamber to urge the seal into sealing engagement with a surface defining the first chamber.

A cylinder device includes a piston and a piston rod disposed movably, and a movable body in which another end portion of the piston rod is inserted. The piston rod includes a first pin groove that extends along an axial direction and through which a support pin is inserted. The support pin is also inserted through second pin grooves formed in the movable body and having a substantially L-shaped cross section. Further, a link pin is inserted through a pin hole on the other end portion of the piston rod. The link pin is inserted through third pin grooves in the movable body which are inclined at a predetermined angle with respect to the axis of the movable body. In addition, under a moving action of the piston, the movable body is displaced linearly, and thereafter, is rotationally displaced by the link pin moving along the third pin grooves.

A piston assembly for a nailer is provided, and includes a piston body with an upper surface, a lower surface and a peripheral edge. A peripheral gland is located between the upper and lower surfaces, the gland having an inner closed end and defining an annular space. An annular piston seal is disposed in the gland, and a plurality of spaced air ports are disposed adjacent the peripheral edge, the ports each being in fluid communication with the gland. The gland and the seal are dimensioned so that during a power cycle of the nailer, pressurized air generated during a fastener driving stroke enters the ports and radially expands the seal for enhancing friction between the seal and a surrounding cylinder. During a return stroke, the seal is radially retracted within the gland to reduce friction between the seal and the cylinder.

A piston assembly for a nailer is provided, and includes a piston body with an upper surface, a lower surface and a peripheral edge. A peripheral gland is located between the upper and lower surfaces, the gland having an inner closed end and defining an annular space. An annular piston seal is disposed in the gland, and a plurality of spaced air ports are disposed adjacent the peripheral edge, the ports each being in fluid communication with the gland. The gland and the seal are dimensioned so that during a power cycle of the nailer, pressurized air generated during a fastener driving stroke enters the ports and radially expands the seal for enhancing friction between the seal and a surrounding cylinder. During a return stroke, the seal is radially retracted within the gland to reduce friction between the seal and the cylinder.

Embodiments of a combination piston and piston ring to reduce the volume of a crevice defined between the circumferential wall of a cylinder and a portion of the outer wall of a piston within the cylinder, the portion extending down from the top of the piston. The combination piston and piston ring is configured such that pressurized fluid within the cylinder reliably urges a radial face of the piston ring to sealingly engage the circumferential wall of the cylinder, even as the piston reciprocates within the cylinder.

Embodiments of a combination piston and piston ring to reduce the volume of a crevice defined between the circumferential wall of a cylinder and a portion of the outer wall of a piston within the cylinder, the portion extending down from the top of the piston. The combination piston and piston ring is configured such that pressurized fluid within the cylinder reliably urges a radial face of the piston ring to sealingly engage the circumferential wall of the cylinder, even as the piston reciprocates within the cylinder.

A split ring seal has: a first circumferential end and a second circumferential end; an inner diameter surface and an outer diameter surface; a first axial end face and a second axial end face. The outer diameter surface has a sealing surface. The first axial end face has: a first section; a second section outboard of the first section; and an axial protrusion between the first section and the second section The second axial end face has: a first sealing surface; a second sealing surface radially outboard of the first sealing surface; a circumferential channel between the first surface and the second sealing surface; and a plurality of channels extending radially outward from the circumferential channel.

The present disclosure provides an open-faced piston with a circumferential groove into which a piston ring assembly is arranged. Openings at the bottom of the circumferential groove and between a front land of the open-faced piston and the piston face are provided. The openings are arranged to allow for a combustion reaction to propagate through the volume defined between the bottom of the piston ring assembly and the piston face such that at least a portion of an air and fuel mixture located in that volume is reacted.

The present disclosure provides an open-faced piston with a circumferential groove into which a piston ring assembly is arranged. Openings at the bottom of the circumferential groove and between a front land of the open-faced piston and the piston face are provided. The openings are arranged to allow for a combustion reaction to propagate through the volume defined between the bottom of the piston ring assembly and the piston face such that at least a portion of an air and fuel mixture located in that volume is reacted.