Rotary machines comprising four cylinders in a star

Rotary machine of the explosion engine type, pumps, or compressors including:

• a rotary shaft with axis A;
• four cylinders in a star aligned in pairs on two axes B and C perpendicular to the axis A and to each other, axis B lying in one plane and axis C being in a further separate plane;
• a first assembly of two pistons suitable to slide within two of the said cylinders and connected together head to tail by a first rigid cross piece;
• a second assembly of two pistons suitable to slide within the other two cylinders and connected together head to tail by a second rigid cross piece;
• and a mechanism suitable to transform the alternating slidings of these two assemblies into rotation of the shaft or conversely, said mechanism including two eccentrics solid with each other and mutually out of phase by 180.degree. around the same journal which is solid with the said shaft and is itself eccentric with respect to the shaft, each eccentric being mounted in the central zone of one of the cross pieces in such a way as to be able to pivot within it, wherein on the one hand, each cross piece is guided for smooth sliding in two sleeves which are integral with the casing of the machine and therefore with the cylinders and that, on the other hand, each piston is fixed on one extremity of the corresponding cross piece by a device permitting relative transverse, but not longitudinal, displacements of said piston relative to the said cross piece.