Width control and alignment means for continuous extensible web

In combination, a contour electrifier and a control system for web alignment, registration and longitudinal tensioning along a web path generally centered relative to a work station in which said contour electrifier is operative and extends transversely across said web path at a predetermined location therealong:

• said contour electrifier comprising a rotatable heatable cylinder including journal means therefor, an elongated rest member in adjacent, radially spaced, longitudinally extending relationship to said cylinder, the interrelationship between said cylinder and said rest member further being such that circumferentially outer surface portions of said cylinder vary in a longitudinally repeating manner in their radial spacings from adjacent surface portions of said rest member;
• and said control system comprising a pair of driving roller means, each one located transversely across said web path, one located upstream, the other located downstream, respectively, from said work station, for translating such a web along said web path and also for maintaining a desired longitudinal tension of such a web between respective ones of said pair of driving roller means;
• first drive means for driving each of said driving roller means including selectively variable rotational speed control means for differentially rotatably driving one of said driving roller means of said pair at a different surface speed with respect to the other thereof;
• a steering frame assembly, including two guide roller means located transversely across said web path upstream from said work station with respect to the direction of web movement along said web path, said steering frame assembly having a pivot axis located centrally relative to said web path and perpendicularly relative to said steering frame assembly for reciprocal arcuate movements of said guide roller means transversely across said web path;
• second drive means for reciprocally pivoting said steering frame assembly;
• a first and a second position sensing means, located in opposed relationship to one another at opposed sides of said web at a present longitudinal location therealong, each of said sensing means being movable transversely such that a movement of one toward or away from the other is accompanied by a corresponding movement in the other and each one of said position sensing means being able to instantaneously sense the spatial position of its related one side edge of said web relative to said one sensor and to generate a position signal representative of such transverse web edge position so sensed;
• alignment control means responsive to signal from said first position sensing means and suitable for actuating said second drive means for causing said steering assembly to transversely position said web continuously;
• reversible drive means responsive to signal from said seond position sensing means to follow transverse width changes in said web and also to follow movements of said web produced by said steering frame assembly;
• a third position sensing means cooperating with said first and second sensing means for instantaneously sensing position changes in said first and second sensing means and for generating a third signal representative of the transverse width of said web, and width control means for comparing said third signal to a constant factor representative of a predetermined width desired for said web and for generating a difference signal representative of any differences sensed, said difference signal being operative for controlling said first drive means for variably and differentially rotatably driving one of said driving roller means with respect to said other driving roller means for thereby causing variations in longitudinal tensioning of the web sufficient to maintain continuously said desired web width;
• whereby said web is substantially accurately guided through said contour electrifier in predetermined registration with said radial spacings in said contour electrifier.

In combination, an electrifier and a control system for web alignment, registration, and longitudinal tensioning along a web path generally centered relative to a work station in which said electrifier is operative and which extends transversely across said web path at a predetermined location therealong:

• said electrifier having an outer walled hollow revolvable electrifier cylinder interiorly provided with heating means and control means for the heating means, said electrifier having an outer circumference which systematically varies in cross-sectional diameter within a predetermined range;
• and said control system comprising a pair of driving roller means, each one located transversely across said web path, one located upstream, the other located downstream respectively, from said work station, for translating such a web along said web path and also for maintaining a desired longitudinal tension of such a web between respective ones of said pair of driving roller means;
• first drive means for driving each of said driving roller means including selectively variable rotational speed control means for differentially rotatably driving one of said driving roller means of said pair at a different surface speed with respect to the other thereof;
• a steering frame assembly, including two guide roller means located transversely across said web path upstream from said work station with respect to the direction of web movement along said web path, said steering frame assembly having a pivot axis located centrally relative to said web path and perpendicularly relative to said steering frame assembly for reciprocal arcuate movements of said guide roller means transversely across said web path;
• second drive means for reciprocally pivoting said steering frame assembly;
• a first and second position sensing means, located in opposed relationship to one another at opposed sides of said web at a preset longitudinal location therealong, each of said sensing means being movable transversely such that a movement of one toward or away from the other is accompanied by a corresponding movement in the other and each one of said position sensing means being able to instantaneously sense the spatial position of its related one side edge of said web relative to said one sensor and to generate a position signal representative of such transverse web edge position so sensed;
• alignment control means responsive to signal from said first position sensing means and suitable for actuating said second drive means for causing said steering assembly to transversely position said web continuously;
• reversible drive means responsive to signal from said second position sensing means for causing said pair of position sensing means to follow transverse width changes in said web and also to follow movements of said web produced by said steering frame assembly;
• a third position sensing means cooperating with said first and second sensing means for instantaneously sensing position changes in said first and second sensing means and for generating a third signal representative of the transverse width of said web;
• and width control means for comparing said third signal to a constant factor representative of a predetermined width desired for said web and for generating a difference signal representative of any differences sensed, said difference signal being operative for controlling said first drive means for variably and differentially rotatably driving one of said driving roller means with respect to said other driving roller means for thereby causing variations in longitudinal tensioning of the web sufficient to maintain continuously said desired web width.