FIELD: mechanical engineering; internal combustion engines and pumps. SUBSTANCE: device has reciprocating motion unit with first and second reciprocating members 14 limited by flat guide surfaces 19. Pair of side plates 15 provided with slots to form outlet port 33 is coupled with each end of guide surfaces. Eccentric journal 12 of crankshaft is arranged in port 33, and drive unit 23 is installed on eccentric journal 12 for engaging with guide surfaces 19 of members 14. Side plates 15 and members 14 have mating longitudinal members to transmit load. Longitudinal members can be made in form of ribs and slots. EFFECT: enlarged operating capabilities. 10 cl, 9 dwg
