Systems and methods are described for a reciprocating mechanism. The system includes at least one axially translating y-axis component configured to reciprocate substantially along a y-axis with a reciprocating motion of a piston assembly relative to a base. The system also includes at least one x-axis component slidingly coupled via at least one bearing assembly to and translating with the at least one y-axis component along the y-axis. The at least one x-axis component is configured to reciprocate substantially perpendicularly to the y-axis relative to the at least one y-axis component, and includes an orbital output component and an orbital linking component disposed substantially concentric with the orbital output component. The system also includes a stationary output component rotatably attached to the base in a direction that is substantially perpendicular to both the x-axis and y-axis, and a stationary linking component rotatably attached to the base in a direction that is substantially concentric with the stationary output component.

A piston unit of a working cylinder includes a piston and a piston rod. The piston has an axial bore hole formed therein. The piston rod is received in the axial bore hole. The piston rod and the piston are connected by a material-bond by a circumferential laser ring weld seam. The laser ring weld seam defines a pressure medium-tight sealing plane.

A piston unit of a working cylinder includes a piston and a piston rod. The piston has an axial bore hole formed therein. The piston rod is received in the axial bore hole. The piston rod and the piston are connected by a material-bond by a circumferential laser ring weld seam. The laser ring weld seam defines a pressure medium-tight sealing plane.

A cylinder unit includes a piston disposed in the cylinder bore that is connected to a piston connecting frame member. The piston connecting frame member replaces a conventional connecting rod, and reciprocates exclusively along the bore axis. A crank connecting member has a linear rail at its top that is captured in a transverse gap along the bottom of the piston connecting frame member, and converts the circular movement of a crank throw to linear motion of the piston connecting frame member.

An internal combustion may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted therein. The piston may be configured to move in a first stroke that includes an expansion stroke portion and a non-expansion stroke portion. The engine may further include first and second piston rod portions extending from opposite faces of the piston. A recess in the piston rod portions may be configured to communicate gases between a combustion chamber and locations outside the cylinder. There may also be a chamber surrounding the first or second piston rod portion, the chamber configured to be supplied with gas and the chamber being isolated from the first combustion chamber and the second combustion chamber.

An internal combustion may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted therein. The piston may be configured to move in a first stroke that includes an expansion stroke portion and a non-expansion stroke portion. The engine may further include first and second piston rod portions extending from opposite faces of the piston. A recess in the piston rod portions may be configured to communicate gases between a combustion chamber and locations outside the cylinder. There may also be a chamber surrounding the first or second piston rod portion, the chamber configured to be supplied with gas and the chamber being isolated from the first combustion chamber and the second combustion chamber.

A piston and piston rod assembly includes a piston rod having a first portion and a smaller second portion extending from the first portion. The second portion has a circumferential groove that receives at least one sealing ring or O-ring located between the first portion and the free end of the second portion. A piston has an aperture extending between two ends, with the top open end having a larger diameter than the bottom open end. The second portion of the piston rod is inserted through the aperture of the piston so that the free end of the second portion emerges through the top open end of the piston and compresses the at least one sealing ring or O-ring with the inner surface of the piston. The free end of the second portion of the piston rod is cold-worked to overlie at least a portion of the top open end of the piston.

A piston and piston rod assembly includes a piston rod having a first portion and a smaller second portion extending from the first portion. The second portion has a circumferential groove that receives at least one sealing ring or O-ring located between the first portion and the free end of the second portion. A piston has an aperture extending between two ends, with the top open end having a larger diameter than the bottom open end. The second portion of the piston rod is inserted through the aperture of the piston so that the free end of the second portion emerges through the top open end of the piston and compresses the at least one sealing ring or O-ring with the inner surface of the piston. The free end of the second portion of the piston rod is cold-worked to overlie at least a portion of the top open end of the piston.

A piston may be provided which includes a first piston body portion having an end wall extending radially about a central axis along which the piston reciprocates. The piston may also include a second piston body portion having an end wall extending radially about a central axis along which the piston reciprocates. The first piston body portion and the second piston body portion are axially opposed. The piston may further include a first piston rod bore disposed in the first piston body portion extending along the central axis and a second piston rod bore disposed in the second piston body portion extending along the central axis. The piston may also include a circumferential opening disposed between the mating of the first piston body portion with the second piston body portion.

A piston may be provided which includes a first piston body portion having an end wall extending radially about a central axis along which the piston reciprocates. The piston may also include a second piston body portion having an end wall extending radially about a central axis along which the piston reciprocates. The first piston body portion and the second piston body portion are axially opposed. The piston may further include a first piston rod bore disposed in the first piston body portion extending along the central axis and a second piston rod bore disposed in the second piston body portion extending along the central axis. The piston may also include a circumferential opening disposed between the mating of the first piston body portion with the second piston body portion.