Abstract Moving tubing, such as of plastic film, is continuously gusseted in the longitudinal direction, by pulling apart opposed side sections of the tubing, at a local station by application of vacuum force selectively to the surface of the tube, leaving one or more section(s) of the tubing free of such vacuum force, and continuously inwardly tucking such free section(s) by means of gusset blade(s) or the like, or alternately by means of atmospheric force pressing inwardly on said free section(s). In species embodiments of the invention, the vacuum suction is applied by means of opposed perforate belts or rolls through which the vacuum is pulled, and which are operated at essentially the same rate of speed as the forward movement of the tubing.
IN THE METHOD OF GUSSETING A FLEXIBLE TUBE, THE STEPS OF: I. CONTINUOUSLY ADVANCING THE TUBE, II. SELECTIVELY APPLYING A VACUUM SUCTION TO OPPOSED EXTERIOR SURFACE AREAS OF THE TUBE TO OPEN THE TUBE, III. LEAVING A SELECT EXTERIOR SURFACE AREA OF THE TUBE FREE OF THE APPLICATION OF SAID VACUUM SUCTION IV. MAINTAINING A NEGATIVE GAUGE PRESSURE WITHIN SAID TUBE IN THE VICINITY OF SAID VACUUM SUCTION APPLYING STEP, AND
Claim 2
Dependent Claim
71 words
IN THE METHOD OF GUSSETING A FLEXIBLE TUBE, THE STEPS OF: I. CONTINUOUSLY ADVANCING THE TUBE, II. SELECTIVELY APPLYING A VACUUM SUCTION TO OPPOSED EXTERIOR SURFACE AREAS OF THE TUBE TO OPEN THE TUBE, III. LEAVING A SELECT EXTERIOR SURFACE AREA OF THE TUBE FREE OF THE APPLICATION OF SAID VACUUM SUCTION IV. MAINTAINING A NEGATIVE GAUGE PRESSURE WITHIN SAID TUBE IN THE VICINITY OF SAID VACUUM SUCTION APPLYING STEP, AND
Claim 3
Dependent Claim
33 words
The method of claim 1 where said vacuum suction step comprises applying vacuum suction faces to the tube which move at generally the same speed as the speed of advancement of the tube.
Claim 4
Dependent Claim
39 words
The method of claim 1 wherein said inward tucking step is solely by inward collapse of said free sections via atmospheric pressure acting cooperatively with the application of said vacuum suction and the negative gauge pressure within the tube.
Claim 5
Dependent Claim
36 words
The method of claim 1 wherein said inward tucking step comprises applying guiding means to the tube to inwardly tuck said fRee surface area assisted by the bias of atmospheric pressure bearing inwardly on the tube.