Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
F01B7/00—Machines or engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders
F01B7/20—Machines or engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders with two or more pistons reciprocating one within another, e.g. one piston forming cylinder of the other
