Description
Class F01B : MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
Subclass 3/08: Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis the piston motion being transmitted by curved surfaces by multi-turn helical surfaces and automatic reversal the helices being arranged on the pistons