Sealer apparatus for plastic film processing including an adjustably mounted seal bar, particularly for bag making machines

A plastic sealing apparatus for forming an elongated seal within the plastic web, said plastic sealing apparatus comprising a rigid support structure having a first wall member and a second wall member, upper and lower seal bar units secured to said wall members and extending in spaced aligned relation, said seal bar units defining a plastic web path therebetween, a first of said upper and lower seal bar units being mounted for movement and defining a movable seal bar unit for movement into sealing engagement with the second of said seal bar units, said second seal bar insert mounted for forming a substantially stationary seal bar unit, comprising the improvement including:

• a drive system mounted to said support structure and coupled to said movable seal bar unit for moving said movable seal bar unit into said sealing engagement with said web and pressing said web into engagement with the opposed stationary seal bar unit,
• a plurality of laterally spaced fluidic cylinder units coupled to said support structure and coupled to said substantially stationary seal bar unit, each said fluidic cylinder unit including a cylinder having a front wall and a back wall, said back wall being fixed to said support structure, a piston within said cylinder having a piston rod extending from the front wall and coupled to said substantially stationary seal bar unit, said fluidic cylinder units having a fluidic input for receiving of fluid within said cylinder between said piston and said back wall of said cylinder, and a second piston rod secured to said piston and projecting outwardly through said back wall of said cylinder unit, and,
• an adjustable unit secured to said second piston rod for varying the position of said second piston rod and said piston relative to said back wall and thereby varying the position of said first piston rod and said substantially stationary seal bar unit in position relative to said moveable seal bar unit, each said fluidic cylinder unit providing for the spacing of the seal bar unit in a non-operative position and in an adjustable operative position and functioning as a cushioning unit to allow some slight penetration and lost of motion during the sealing engagement of the moveable seal bar unit and the substantially stationary seal bar unit.