Transverse sealer for a bag maker with variable operating speed

A bag maker adapted to bend an elongated bag-making film into a tubular shape to form a bag and to simultaneously fill said bag with a batch of articles, said bag maker comprising:

• a web supporting means supporting a web roll having a web of said elongated film wound around a core shaft;
• a former for forming said web into a tubular shape;
• web guiding means for guiding said web from said web roll to said former and said tubularly formed web on a longitudinal downward film path;
• a longitudinal sealer for sealing side edges of said tubularly formed web longitudinally;
• a film pulling means for causing said film to move on said downward film path;
• and
• a transverse sealer which comprises:
• a pair of sealing units disposed on opposite sides of said film path, said pair of sealing units being adapted to undergo cyclic motion and transversely seal said film to thereby form a bag while moving on an adjacent path along said film path in said cyclic motion, said adjacent path including a stripping region in which said sealing units serve to strip said film and a sealing region where said sealing units transversely seal said film, said sealing units passing said stripping region immediately before passing said sealing region in said cyclic motion;
• and
• a control unit for controlling variations in speed of motion of said sealing units, causing said sealing units to move faster than said film in said stripping region and slower than said film in said sealing region without changing the period of said cyclic motion.

A bag maker adapted to bend an elongated bag-making film into a tubular shape to form a bag and to simultaneously fill said bag with a batch of articles, said bag maker comprising:

• a web supporting means supporting a web roll having a web of said elongated film wound around a core shaft;
• a former for forming said web into a tubular shape;
• web guiding means for guiding said web from said web roll to said former and said tubularly formed web on a longitudinal downward film path;
• a longitudinal sealer for sealing side edges of said tubularly formed web longitudinally together;
• a film pulling means for causing said film to move on said downward film path;
• and
• a transverse sealer which comprises:
• sealing means for undergoing a continuous cyclic motion along a closed trajectory consisting of a sealing region which is along said film path and a non-sealing region and transversely sealing said film only while moving in said sealing region in said cyclic motion;
• and
• a control unit for varying the speeds of motion of said sealing means and said film in said cyclic motion without changing the period of said cyclic motion such that said sealing means and said film move at different speeds in said sealing region.