Abstract: An air compressor utilizing one or more pistons reciprocating within water cooled cylinders and operating in an oil free environment. Each piston is reciprocated by rotation of motor driven, balanced rotors, through a reciprocating and oscillating shuttle member. A centrally sleeved, hollow ball, accommodates shuttle member movement, while interconnecting the shuttle member and the rotors. Positive lubrication is provided for the rotor bearings, the hollow ball and shuttle member and the reciprocating piston shafts. The rotors are driven in opposite directions by motors mounted to maintain constant torque on the rotors.

Abstract: The hydraulic head especially for an "in line" injection pump, comprises a cylinder forming a pump chamber, in which a pump piston moves, having at least one fuel supply orifice formed in its cylindrical wall. The hydraulic head has a deflector element situated axially at the level of this supply orifice to deflect a jet of fuel capable of emerging from said orifice. A delivery connector is connected to the cylinder, and is constituted by an elastic ring of cylindrical form. The ring is open and has two ends arranged to come into contact with one another, said ends being separable from one another.