Automated web chop-out control for cut-to-mark cut-off machine

A method of automatically controlling at least first and second cut-off machines each having knives operable in a cut-to-mark mode wherein the knives cut a moving web divisible into a leader having a first set of registration marks and trailer having a second second of registration marks, there being a transition between the first and second sets of marks, comprising:

• (a) directing the leader to said first cut-off machine;
• (b) causing the knives of said first cut-off machine to cut the leader in the cut-to-mark mode at the registration marks of the first set;
• (c) applying a target to the trailer adjacent a first preselected registration mark of the second set;
• (d) tracking the target electronically to a shear upstream of the cut-off machines;
• (e) automatically and repetitively severing the web transversely at the shear two or more times when the target is tracked to the shear whereby a preselected portion of the web comprising the transition between said registration marks is chopped out of the web;
• (f) tracking the leading edge of the trailer electronically from said shear to a position intermediate the shear and said cut-off machines after said preselected web portion has been chopped from the web;
• (g) directing the trailer to said second cut-off machine;
• (h) causing the knives of said second cut-off machine to cut the trailer automatically at a second preselected registration mark of the second set following the leading edge of the trailer;
• and
• (i) causing the knives of said second cut-off machine to cut the trailer automatically in the cut-to-mark mode at the registration marks of the second set which follow said second preselected registration mark.

Apparatus for automatically controlling a cut-off machine having knives operable in a cut-to-mark mode wherein the knives cut a moving web divisible into a leader having a first set of registration marks and trailer having a second set of registration marks, there being a transition between the first and second sets of marks, said trailer being provided with a target adjacent a first preselected registration mark of the second set, comprising:

• (a) a shear upstream of said cut-off machine for severing the web transversely;
• (b) means for tracking said target electronically to said shear and for causing said shear to sever the web repetitively two or more times when said target is tracked to said shear whereby a preselected portion of the web comprising the transition between said registration marks is chopped out of the web;
• (c) means for tracking the leading edge of the trailer electronically from said shear to a position intermediate the shear and said cut-off machine after said preselected web portion has been chopped from the web;
• and
• (d) means for causing said knives to repetitively cut the trailer at said second set of registration marks in the cut-to-mark mode beginning at the position of a second preselected registration mark following the leading edge of the trailer.

Apparatus for automatically controlling at least first and second cut-off machines each having knives operable in a cut-to-mark mode wherein the knives cut a moving web divisible into a leader having a first set of registration marks and a trailer having a second set of registration marks, there being a transition between the first and second sets of marks, said trailer being provided with a target adjacent a first preselected registration mark of the second set, comprising:

• (a) a shear upstream of said cut-off machine for severing the web transversely;
• (b) means for tracking said target electronically to said shear and for causing said shear to automatically sever the web repetitively two or more times when said target is tracked to said shear whereby a preselected portion of the web comprising the transition between said registration marks is chopped out of the web;
• (c) means for directing the leader to said first cut-off machine;
• (d) means for causing the knives of said first cut-off machine to cut the leader in the cut-to-mark mode at the registration marks of the first set;
• (e) means for tracking the leading edge of the trailer from said shear to a position intermediate the shear and said cutoff machines after said preselected web portion has been chopped from the web;
• (f) means for directing the trailer to said second cut-off machine;
• and
• (g) means for causing the knives of said second cut-off machine to repetitively cut the trailer at said second set of registration marks in the cut-to-mark mode beginning at the position of a second preselected registration mark following the leading edge of the trailer.