Patent ID: 7255070

Claim:
A pump, comprising: a pump mechanism; and an internal combustion engine comprising: at least one set of two outer pistons and a central piston disposed between the outer pistons, the pistons reciprocating on a common axis, at least one piston being a free piston; an end of a first outer piston and a first end of the central piston, in conjunction with a cylinder for the first outer piston and the central piston, defining a first combustion chamber; and an end of a second outer piston and a second end of the central piston, in conjunction with a cylinder for the second outer piston and the central piston, defining a second combustion chamber, wherein at least one piston includes at least one connecting member communicating with the pump mechanism so as to drive the pump mechanism in correspondence with the piston, and wherein the element external to the cylinder is an element of a pumping mechanism; wherein the element of the pumping mechanism comprises a movable chamber.