Abstract: At a transition between first and second sets of index marks on a web, a target is applied adjacent the initial mark of the second set. The target is sensed and as a result the web is severed transversely at the transition between the sets of marks. A gap is formed in the web. A microcomputer synchronizes a cut-off machine with the second set of marks while the cut-off machine is in the gap whereby operator intervention is eliminated and scrap minimized.

Abstract: The size of the gap between the leading and trailing portions of a severed web is monitored with respect to an upper limit. The severed web is cut into box blanks which are transported on a stacker conveyor in shingled relation. The speed of the severed web through the corrugator is continuously controlled to prevent the gap from exceeding the limit when the gap reaches the stacker conveyor. Alternatively, the stacker conveyor is temporarily stopped until the size of the gap falls below the limit, and the stacker conveyor is re-started before the gap can close. In either case, the gap control prevents bumping of consecutive box blanks on the stacker conveyor following a change-over of production runs while insuring that the first blank of the new production run shingles on the last blank of the old production run with sufficient tail to insure retention of the first blank by stacker conveyor suction cups or tail grabbers.

Abstract: Box blanks produced from a moving web by a paperboard corrugator are shingled on a stacker conveyor. The corrugator includes a shear which severs the web in response to a production run change signal into leading and trailing portions. A cut-off machine cuts the severed web portions into the box blanks. Box blanks cut from the leading portion of the severed web are part of the old production run. Box blanks cut from the trailing portion of the severed web are part of the new production run. The leading edge of the trailing portion of the severed web is tracked to the cut-off machine. The trailing edge of the first full size box blank of the new production run is detected at a first position relative to the stacker conveyor. The trailing edge of the first full size box blank is then tracked to a second position on the stacker conveyor. When the trailing edge of the first full size box blank reaches the second position, a command signal is generated.

Abstract: Lateral and rotary axis controls for automatically setting up the position of a rotary element mounted on a rotatable shaft in a box-making machine. The lateral position of the element determines the position of the creases and slots in a box blank. The rotary position of the element determines the depth of the slots in the blank.

Abstract: An automatic web splice control system for a web splicer apparatus including a running web roll and a ready web roll and a splice mechanism for splicing the expiring end of the running web to the leading end of the ready web. The system provides successive measurements of the length of web unwound from the running web roll per revolution of the roll. The length of web unwound per revolution of the roll is compared to a first pre-selected length. When the length unwound per revolution of the roll falls below the first pre-selected length, the system determines the length of web unwound from the roll per a pre-selected number of revolutions of the roll. When the length of web unwound per the pre-selected number of revolutions of the roll reaches a second pre-selected length, a warning signal is generated. Thereafter, the measurement of length of web unwound per revolution of the roll is dynamically incremented.

Abstract: An improved cut-off control for operating a cut-off mechanism to cut sheets of uniform length from a moving web. The cut-off control comprises means for computing actual sheet length and sheet length error and for generating separate signals indicative thereof. Digital means cylically increment and decrement the actual sheet length signal. Digital means determine whether the sheet length error is within prescribed limits of the uniform sheet length in response to the cylically incremented and decremented actual sheet length signal. A positioning motor corrects the sheet length error if it is determined to be outside the prescribed limits. Digital means simulate the correction of sheet length error effected by the positioning motor and correct the actual sheet length signal as a function thereof.

Abstract: An improved production counter for a corrugator including a knife for cutting web material into sheets. First and second digital signals are generated. The first digital signal indicates a predetermined number of sheets of web material to be cut by the knife. The second digital signal indicates the instantaneous number of sheets of web material cut by the knife. The second digital signal is cyclically incremented and decremented by predetermined counts. Coincidence of the cyclically varied second digital signal to the first digital signal is detected. A warning signal indicative of a preselected number of sheets of web material remaining to be cut is generated when the cyclically varied second digital signal and the first digital signal coincide.