Oscillating piston pump or similar machine

In combination

• a first housing component having a plurality of radially inwardly directed partition walls;
• a first pair of mutually opposite end members, each end member being disposed at a respective end of said first housing component to define a first hollow space therewith;
• a second housing component;
• a second pair of mutually opposite end members, each said end member of said second pair being disposed at a respective end of said second housing component to define a second hollow space therewith;
• a one-piece rocker piston member slidably mounted in and extending within each said housing component, said piston member having a plurality of radically directed wings disposed in alternating relation with said partition walls and a cylindrical surface in said second hollow space;
• a crank arm mechanism in said second hollow space coupled to said cylindrical surface of said piston member for oscillating said piston member;
• a sealing ring sealingly engaging about said piston member and located in sealing contact with at least one of said end members of said housing components to seal said hollow spaces from each other along said piston member;
• a cover member on a side of said first housing component opposite said second housing component;
• and
• connecting means removably connecting said cover member to said second housing component.