Patent ID: 7305937

Claim:
A rotary machine comprising: a housing divided into a first stationary portion and a second rotational portion, the housing having an axis, the second rotational portion being supported for rotation with respect to the stationary portion about the housing axis; the first and second portions of the housing cooperating to define a generally toroidal passage which is coaxial with the housing axis, the toroidal passage having a cross section; a first piston disposed in the passage; a second piston disposed in the passage; each piston having an interconnection mechanism for selectively interconnecting the piston to either the stationary portion or the rotational portion; each piston comprising: a central piston body; a first plunger plate defining a leading face of the piston; a second plunger plate defining a trailing face of the piston; the interconnection mechanism at least partially disposed in the piston body; a first connecting member movably interconnecting the first plunger plate with the interconnection mechanism; a second connecting member movably interconnecting the second plunger plate with the interconnection mechanism, the first and second connecting members being in mechanical communication such that movement of one of the plunger plates towards the central piston body causes corresponding movement of the other of the plunger plates away from the central piston body; the connecting members and the interconnection mechanism each having a length, the combined length of the connecting members and the interconnection mechanism being greater than a length of the central piston body; and the interconnection mechanism further including an engagement member operable to interconnect the piston with the stationary portion of the housing or with the rotational portion of the housing, the engagement member being in mechanical communication with the connecting members such that movement of the connecting members in the direction of rotation of the rotational portion of the housing causes the engagement member to interconnect the piston with the rotational portion of the housing and movement of the connecting members in a direction opposite the direction of rotation causes the engagement member to interconnect the piston with the stationary portion of the housing; and wherein a compression area is defined between the first and second pistons such that when the first piston moves toward the second piston, a gas in the compression area is compressed.