Method and apparatus for pre-tearing strings of air-filled packing materials

Abstract

Method and apparatus which facilitate the tearing of packing materials into desired lengths by pre-tearing them along the rows of perforations which are provided for that purpose. In the disclosed embodiments, a preconfigured packing material having inflatable chambers separated by rows of perforations is fed at a predetermined speed in a direction generally perpendicular to the rows and periodically pulled upon rather abruptly to produce a partial tearing of the material along central portions of the rows of perforations.

1 - 17 . (canceled)  
     
     
         18 . Apparatus for making a packing material in the form of a string of air filled packing cushions with rows of perforations extending across the material between the cushions, comprising: means for feeding two superposed layers of film material in which the perforations have been formed along a path, means engagable with the film material for partially tearing the material along the rows of perforations, means for injecting air between the two layers of film material, and means for sealing the layers of film material together to form air-filled cushions between the partially torn rows of perforations.  
     
     
         19 . The apparatus of  claim 18  wherein the means for partially tearing the material comprises a tear roller having an arcuate section which periodically engages a central portion of the material and a section adjacent to the arcuate section which remains out of driving engagement with the material.  
     
     
         20 . The apparatus of  claim 19  wherein the means for partially tearing the material also includes a feed roller with a surface in continuous driving engagement with the film material for feeding the material at a predetermined speed.  
     
     
         21 . The apparatus of  claim 20  wherein the tear roller rotates faster than the feed roller.  
     
     
         22 . A method of making a packing material in the form of a string of air-filled packing cushions with rows of perforations extending across the material between the cushions, comprising the steps of: feeding two superposed layers of film material in which the perforations have been formed along a path, partially tearing the material along the rows of perforations, injecting air between the two layers of film material, and sealing the layers of film material together to form air-filled cushions between the partially torn rows of perforations.  
     
     
         23 . The method of  claim 22  wherein the material is torn by continuously engaging a central portion of the film material with a feed roller to feed the material at a predetermined speed, and periodically exerting an abrupt pull on the material by engaging an edge portion of the material with a tear roller having an interrupted surface with an arcuate section which engages the material to exert the pull only during a portion of a rotation of the roller.  
     
     
         24 . Apparatus for making a string of air-filled packing cushions from an elongated strip of preconfigured film having a plurality of uninflated chambers formed between two layers of the film with rows of perforations extending across the film between successive ones of the chambers, comprising: means engagable with a central portion of the film for feeding the film along a path at a predetermined speed, a tear roller having a surface that rotates faster than the predetermined speed and is intermittently engagable with a central portion of the film for exerting an abrupt periodic pull on the film which produces a partial tearing of the film along the central portions of the rows of perforations, means for injecting air between the layers of film after the material is partially torn along the rows of perforations to inflate the chambers, and means for sealing the chambers to retain the air therein.  
     
     
         25 . The apparatus of  claim 24  wherein the surface of the tear roller has an arcuate section which periodically engages the central portion of the film and a section adjacent to the arcuate section which remains out of driving engagement the film.  
     
     
         26 . The apparatus of  claim 24  wherein the means for feeding the material at a predetermined speed comprises a feed roller with a surface in continuous driving engagement with the film.  
     
     
         27 . The apparatus of  claim 26  wherein the tear roller rotates faster than the feed roller.  
     
     
         28 . A method of making a string of air-filled packing cushions from an elongated strip of preconfigured film having a plurality of uninflated chambers formed between two layers of the film with rows of perforations extending across the film between successive ones of the chambers, comprising the steps of: feeding the film along a path at a predetermined speed, intermittently engaging a central portion of the film with a tear roller having a surface that travels faster than the predetermined speed for exerting an abrupt periodic pull on the film which produces a partial tearing along central portions of the rows of perforations, injecting air between the layers to inflate the chambers, and sealing the chambers to retain the air therein.  
     
     
         29 . Apparatus for pre-tearing a film material having a plurality of longitudinally spaced sections with rows of perforations extending across the material between successive ones of the sections, comprising: means for continuously feeding the film material at a predetermined speed, and a continuously rotating tear roller having a surface that travels faster than the predetermined speed and periodically engages a central portion of the material and exerts an abrupt periodic pull on the material which produces a partial tearing of the material along central portions of the rows of perforations.  
     
     
         30 . The apparatus of  claim 29  wherein the surface of the tear roller has an arcuate section which periodically engages the central portion of the material and a section adjacent to the arcuate section which remains out of driving engagement the material.  
     
     
         31 . The apparatus of  claim 30  wherein the means for feeding the material at a predetermined speed comprises a feed roller with a surface in continuous driving engagement with the material.  
     
     
         32 . The apparatus of  claim 31  wherein the tear roller rotates faster than the feed roller.  
     
     
         33 . A method of pre-tearing a film material having a plurality of longitudinally spaced sections with rows of perforations extending across the material between successive ones of the sections, comprising the steps of: engaging the material with a feed roller to continuously feed the material at a predetermined speed in a direction generally perpendicular to the rows of perforations, and engaging a central portion of the material with a tear roller that rotates about a stationary axis and has an eccentric surface travels faster than the predetermined speed and periodically engages the film material to exert an abrupt periodic pull on the material to produce a partial tearing of the material along central portions of the rows of perforations.