A pneumatic hammer includes a piston in an operating cylinder; and a valve mounted at a rear end of the operating cylinder and including a front mechanism, a rear mechanism, and a disc. The rear mechanism includes two opposite inlets, a chamber member, outlets, a relief chamber communicating with the outlets, two opposite inlet channels disposed externally of the chamber member, and two first outlet tunnels disposed externally of the chamber member. The front mechanism includes a chamber element on one surface communicating with the inlet channels, an axial tunnel through a center of the chamber element, and two second outlet tunnels disposed externally of the chamber element. The disc is between the chamber member and the chamber element. The operating cylinder includes intermediate through holes and two inlet passageways having one ends communicating with the axial space and the other ends communicating with the second outlet tunnels.

A pneumatic hammer includes a piston in an operating cylinder; and a valve mounted at a rear end of the operating cylinder and including a front mechanism, a rear mechanism, and a disc. The rear mechanism includes two opposite inlets, a chamber member, outlets, a relief chamber communicating with the outlets, two opposite inlet channels disposed externally of the chamber member, and two first outlet tunnels disposed externally of the chamber member. The front mechanism includes a chamber element on one surface communicating with the inlet channels, an axial tunnel through a center of the chamber element, and two second outlet tunnels disposed externally of the chamber element. The disc is between the chamber member and the chamber element. The operating cylinder includes intermediate through holes and two inlet passageways having one ends communicating with the axial space and the other ends communicating with the second outlet tunnels.

The present invention concerns an air motor comprising a piston and a housing, the piston being received in the housing and dividing the housing into two primary chambers of variable volume. Said motor comprises a first direct supply valve for supplying a first primary chamber of the two primary chambers and a second direct supply valve for supplying the other primary chamber, said two valves each being movable relative to at least one respective seat. The first valve and the second valve are mounted on a same stem movable relative to the housing in a direction parallel to the direction of movement of the piston, and the stem is configured to be moved between a first position and a second position by moving means activated by the piston.

The present invention concerns an air motor comprising a piston and a housing, the piston being received in the housing and dividing the housing into two primary chambers of variable volume. Said motor comprises a first direct supply valve for supplying a first primary chamber of the two primary chambers and a second direct supply valve for supplying the other primary chamber, said two valves each being movable relative to at least one respective seat. The first valve and the second valve are mounted on a same stem movable relative to the housing in a direction parallel to the direction of movement of the piston, and the stem is configured to be moved between a first position and a second position by moving means activated by the piston.

A high efficiency variable cutoff uniflow steam engine with piston operated valves has an exhaust valve that is held open by a spring during the exhaust stroke but is closed at an end of the exhaust stroke by the piston compressing steam in a compartment associated to act on the exhaust valve. The piston continues to move in the same direction a short distance toward top dead center (TDC) compressing a small residual quantity of steam in the cylinder above the piston during the remaining fraction of the exhaust stroke with sufficient pressure to open the steam inlet valve by steam pressure without an impact caused by physical contact with the piston.

A high efficiency variable cutoff uniflow steam engine with piston operated valves has an exhaust valve that is held open by a spring during the exhaust stroke but is closed at an end of the exhaust stroke by the piston compressing steam in a compartment associated to act on the exhaust valve. The piston continues to move in the same direction a short distance toward top dead center (TDC) compressing a small residual quantity of steam in the cylinder above the piston during the remaining fraction of the exhaust stroke with sufficient pressure to open the steam inlet valve by steam pressure without an impact caused by physical contact with the piston.

A high efficiency variable cutoff uniflow steam engine with piston operated valves has an exhaust valve that is held open by a spring during the exhaust stroke but is closed at an end of the exhaust stroke by the piston compressing steam in a compartment associated to act on the exhaust valve. The piston continues to move in the same direction a short distance toward top dead center (TDC) compressing a small residual quantity of steam in the cylinder above the piston during the remaining fraction of the exhaust stroke with sufficient pressure to open the steam inlet valve by steam pressure without an impact caused by physical contact with the piston.

A high efficiency variable cutoff uniflow steam engine with piston operated valves has an exhaust valve that is held open by a spring during the exhaust stroke but is closed at an end of the exhaust stroke by the piston compressing steam in a compartment associated to act on the exhaust valve. The piston continues to move in the same direction a short distance toward top dead center (TDC) compressing a small residual quantity of steam in the cylinder above the piston during the remaining fraction of the exhaust stroke with sufficient pressure to open the steam inlet valve by steam pressure without an impact caused by physical contact with the piston.

An engine block comprising: a combustion chamber, an inlet for introducing a fuel/air mixture into the combustion chamber and an outlet for expelling combusted fuel/air mixture from the combustion chamber; and a piston that reciprocates within the combustion chamber to compress the fuel/air mixture therein, the piston having a closer supported thereon, wherein reciprocating movement of the piston seals the combustion chamber with the closer.

A phaser valve for a piston and cylinder assembly helps to keep a pair of pistons in phase with each other. The phaser valve includes a poppet which is slidable between opposing seats of a valve housing. The poppet includes a head and a stem, both the head and the stem having concave portions which facilitate the flow of hydraulic fluid across the valve. The poppet head has two generally conical ends, so that the head makes a fluid-tight seal with a seat when the head is urged towards either seat. Due to its construction, the phaser valve may be built to fit within a very small space, while still allowing a substantial flow of fluid when the head is not in abutment with one of the seats.