US Patent 7980172 Closure mechanism and waste compaction system including same

A waste compaction system which includes a body defining a waste-receiving receptacle having a perimeter defining an open top end. A bottom wall of the receptacle is vertically movable by a driving system to produce an upwardly directed compaction force within the receptacle. An iris-type closure mechanism extends over the open top end and is displaceable between a first, open position where the closure mechanism surrounds the open top end and a second, closed position where the opening is at least partially closed by the closure mechanism. In the second position of the closure mechanism, the driving system displaces the bottom wall upwards thereby compacting the waste contained within the receptacle against the closure mechanism.