this is the body of the compressor, left is topside, right is bottom. You can see three (only two visible in picture) holes for cylinders, and three cylinders on the right side. cylinders are different size, to increase compression

there is a crank with 3 pistons attached, again, 3 different sizes:

the compressor is made like a "boxer" engine (cfr the volkswagen beetle): the cylinder lining is a separate part than the body:

The cylinder heads have valves that are simply operated by the compressed air. so no tublers or crankshaft: