Packing machine with apparatus for automatically stopping bag material transfer rollers

Claim 1

A packing machine comprising a pair of intermittently operated pinching rollers for intermittently transferring an elongated strip-like bag material of a collapsed plastic film tube, said bag material comprising a series of interconnected bags each having a heat-sealed bottom portion and an opposite opening portion, each bag of said tube having a flap-like margin formed transversely across the bag material between said opening portion and said heat-sealed bottom portion, guide means mounted upstream of said pinching rollers for guiding the bag material through a travel path, said guide means comprising a plate having a V-shaped cross-section having a first leg and a second leg from which said first leg is depended, said second leg having a surface for supporting said bag material so that the respective opening portion of the bag material is directed outwardly of said guide means and said flap-like margin is caused to be raised slightly above the surface when passing over the same, detecting means for detecting said flap-like portion, said detecting means comprising a limit switch having an elongated contact mounted adjacent the surface of said guide means, said contact being releasably engageable with said margin responsive to the raising of said margin above the surface, means for stopping movement of said bag material in response to detection by said detecting means of said flap-like portion, and timer means for stopping rotation of said rollers, said timer means being constructed so that it can be activated longer than the time required for each intermittent travel of the bag material for a distance corresponding to the length of a single bag section.