Molins Machine Co. Inc.

Allan Brent Woolston

An optical encoder generates a train of digital pulses as a function of the length of web material unwound per revolution of an unwinding roll. A counter counts the encoder pulses for each revolution of the roll. The counts of the encoder pulses are accumulated over a first set of revolutions of the roll. A programmed microprocessor effects a base computation of (1) the average change in the number of pulses generated per revolution of the roll and (2) the length of web remaining on the roll after the first set of revolutions. Thereafter, the base computation of web length is updated at each revolution of the roll. The counter may comprise an addressable hardware counter chain alone or in combination with a read/write memory which counts the number of times that the counter chain overflows.

Control system for an unwinding roll

A maximum web speed monitor for limiting the speed of a moving web which is cut into sheets by a knife such as a rotary knife. A digital cut-off control provides separate signals indicative of the web speed and the length of sheets into which the web is cut by the knife. A digital integrator repetitively provides a sample signal indicative of the actual speed of the web based on a preselected sampling interval. Information representative of maximum permissible web speed as a function of sheet length is stored in a PROM. The web speed is prevented from exceeding a maximum permissible speed as a function of the maximum permissible web speed information and the sample signal.

Maximum web speed monitor

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.

Set-up control

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.

Digital cut-off control

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.

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Wynnewood, PA, United States of America

Allan Brent Woolston