Patent ID: 6422272
Filing Date: 2002-07-23
Classification: B65B

Abstract:
A strap sealer having a dual action piston comprising:a housing defining a cylinder, the housing defining a penetration therein; a piston disposed in the cylinder for reciprocating movement therein, the piston having first and second sides, the piston defining upper and lower pressure regions at the first and second sides of the piston; a gas inlet; first and second flow paths extending between the gas inlet and the upper and lower pressure regions, respectively; a valve arrangement for providing flow communication between the gas inlet and the first and second flow paths for supply and exhausting gas to the upper and lower pressure regions; a ram mounted to the piston for reciprocating movement therewith, the ram traversing through the housing penetration, the ram having first and second cross-sectional areas different from each other; and a seal forming assembly operably connected to the ram, wherein as the piston reciprocates within the housing the ram reciprocates through the housing penetration, and wherein when the ram reciprocates through the housing penetration the first cross-sectional area resides at the housing penetration forming a seal therebetween, and wherein when the ram reciprocates through the housing penetration and the second cross-sectional area passes through the housing penetration a vent path is provided from the lower pressure region outwardly to vent gas from the lower pressure region.