Compressed-gas-operated reciprocating piston devices

A compressed-gas-operated reciprocating piston device, which includes a composite cylinder component comprising a rigid inner metal cylinder tube in which the piston reciprocates in use and an outer sleeve moulded of polymerized plastics material and surrounding and bonded to the metal cylinder tube, the sleeve being in contact with the entire outer circumferential surface of the major part of the length of the tube, and the sleeve being formed on its outer surface with a plurality of longitudinally-extending outwardly-projecting integrally-moulded ribs spaced apart around the circumference of the sleeve, the device further including an outer tubular muffler made of polymerized plastics material which surrounds the ribbed sleeve, there being formed within the interior of the muffler, first and second chambers which are in communication with one another via a restricted-flow throat, referred to as the restriction, the cylinder component being formed with at least one gas discharge port in its wall which opens into the first muffler chamber, and the second muffler chamber communicating with the muffler exhaust opening, whereby exhaust gas discharged from the cylinder interior through the gas discharge port passes in sequence via the first muffler, the restriction and the second muffler chamber before reaching the ambient atmosphere via the muffler exhaust opening.