A reciprocating compressor is provided. Bearing holes of a fluid bearing of the compressor may be positioned to correspond to a full reciprocating region of a piston, to reduce/eliminate frictional loss and/or abrasion between a cylinder and the piston. The bearing holes may be concentrated at certain regions of the cylinder to stably support the piston through a full reciprocating range. Compression coil springs may maintain concentric alignment of the cylinder and the piston. Gas through holes may be radially formed at the piston to lower a pressure of a bearing space and allow refrigerant to be smoothly introduced into the bearing space through a gas pocket A casing of the compressor may include an outer shell and an inner shell to attenuate vibration generated due to friction generated by operation of the reciprocating compressor.

A modular motor is disclosed that includes a piston/harmonic drive assembly that is axially cycled. The piston/harmonic drive assembly is coupled to a ball transfer arrangement that converts the axial motion into rotary motion to rotate a rotor that can be used to rotate a drill bit.

A modular motor is disclosed that includes a piston/harmonic drive assembly that is axially cycled. The piston/harmonic drive assembly is coupled to a ball transfer arrangement that converts the axial motion into rotary motion to rotate a rotor that can be used to rotate a drill bit.

A piston unit includes a piston which has a rolling element seat configured to rotatably support a rolling element. The rolling element seat has a bearing surface with a surface coating composed of a polymer compound or with a ceramic surface coating.

Filter assemblies and components therefor, are described. In an example arrangement, the crankcase ventilation filter assembly is configured to be serviced from either the top or the bottom. A rotational indexing arrangement is to ensure appropriate orientation of an internally received filter cartridge, and other components of the arrangement are provided. Methods of assembly, servicing and use are described.

Filter assemblies and components therefor, are described. In an example arrangement, the crankcase ventilation filter assembly is configured to be serviced from either the top or the bottom. A rotational indexing arrangement is to ensure appropriate orientation of an internally received filter cartridge, and other components of the arrangement are provided. Methods of assembly, servicing and use are described.

Filter assemblies and components therefor, are described. In an example arrangement, the filter assembly is configured to be serviced from either the top or the bottom. A rotational indexing arrangement is to ensure appropriate orientation of an internally received filter cartridge, and other components of the arrangement are provided. Methods of assembly, servicing and use are described.

Filter assemblies and components therefor, are described. In an example arrangement, the filter assembly is configured to be serviced from either the top or the bottom. A rotational indexing arrangement is to ensure appropriate orientation of an internally received filter cartridge, and other components of the arrangement are provided. Methods of assembly, servicing and use are described.

A compressed-gas motor has a cylindrical inner chamber closed gas-tight at a first base surface, and a piston arranged so as to be movable along the cylinder axis in the cylindrical inner chamber. A first opening feeds a compressed gas into the inner chamber, and a second opening discharges a gas from inside the inner chamber. The openings are arranged in the cylinder casing of the cylindrical inner chamber, wherein the first opening is arranged between the second opening and the closed first base surface. The first opening is closable by a first piston part and the second opening by a second piston part. The compressed-gas motor has a resetting device which exerts a force on the piston in the direction of the first base surface of the cylindrical inner chamber if the second piston part does not completely close the second opening.

A compressed-gas motor has a cylindrical inner chamber closed gas-tight at a first base surface, and a piston arranged so as to be movable along the cylinder axis in the cylindrical inner chamber. A first opening feeds a compressed gas into the inner chamber, and a second opening discharges a gas from inside the inner chamber. The openings are arranged in the cylinder casing of the cylindrical inner chamber, wherein the first opening is arranged between the second opening and the closed first base surface. The first opening is closable by a first piston part and the second opening by a second piston part. The compressed-gas motor has a resetting device which exerts a force on the piston in the direction of the first base surface of the cylindrical inner chamber if the second piston part does not completely close the second opening.