Butler Automatic, Inc.

Edward F Meihofer

John W Clifford

George F Corcoran

Tony P DiGirolamo

A web winder of the center wind type drives the web roll through a controllable variable speed mechanical transmission whose input shaft is turned by a variable slip torque modulating device whose torque coupling varies in accordance with the output of a web tension sensor upstream from the web roll to immediately change the angular velocity of the roll to compensate for sudden tension upsets in the web. The amount of slip in that device is detected and compared with a selected reference slip to develop an error signal for controlling the gear-in ratio of the transmission which slows the angular velocity of the roll to compensate for the gradual web tension increase caused by increasing roll size. Thus the winder's speed characteristics are matched at the input of the transmission to the clutch characteristics at all roll diameters so that the winder requires only a minimum size torque modulating device for given web speed and tension conditions.

Variable ratio winder

Web splicing apparatus employs a pair of driven nip rolls which controllably feed web from a running roll into a festoon as web is drawn out of the festoon at a constant rate by a downstream web consuming machine. The nip rolls are driven by a DC motor connected in a closed loop servo system which compares the speed of the web entering the festoon with the web line speed to develop a command signal for the motor. During normal operation, the command signal includes a web velocity trim signal developed by monitoring the position of the festoon dancer relative to a selected reference position so as to minimize tension upsets and to maintain the dancer within its control range. During a splice sequence, the command signal comprises a deceleration ramp having a selected slope to provide controlled deceleration of the web to minimize tension upsets and to permit actuation of the splicing nips prior to actual web stop. After the splice is made, the command signal comprises an acceleration ramp whose slope is automatically adjusted to apply the least necessary tension to the ready web for new roll acceleration consistent with a given splicing speed. Further with this arrangement, the gain of the system is independent of the changing size of the expiring roll.

Driven nip roll splicer

An automatic web splice control system determines when an expiring roll of web of indeterminate caliper reaches a preselected splice radius by sensing when the web roll has diminished to preset first and second radii and measuring the web length resulting from that diminishment to determine web caliper. Then the system computes the roll cross-sectional area between the second radius and the preselected splice radius divided by that caliper to determine in advance the web length that will be drawn from a roll as the roll size diminishes from the second radius to the splice radius. Commencing at the second radius, the system then measures the amount of web drawn from the roll and when that amount equals the precomputed web length, the system generates a splice signal indicating that the roll has diminished to the preselected splice radius.

Auto-splice system

A system for maintaining lateral alignment of web employs a rotating mirror which reflects a light beam from a source of coherent light along a track across the web path. A mirror driven by a synchronous motor is located at the focal point of a parabolic reflector which converts the circular sweep of light from the mirror to rectilinear light that scans along the track and is incident on the track from the same direction all along the length of the track. A retro-reflector on the track reflects the light back to a detector. Thus the system generates an electrical pulse as the light beam crosses the web edge and this pulse is compared to the phase angle of the power driving the synchronous motor. This phase relationship is then used to develop an error signal to return the web to its reference location.

Web alignment system

In a web tension control system in which web drawn from a variably braked roll passes through a festoon, a selected amount of web is maintained in the festoon by variably braking the roll. The system maintains accurate control of the festoon dancer position over a wide range of web tensions and roll diameters by means of a separate control loop whose output is a relatively slowly changing voltage proportional to the average deviation of the festoon dancer from its selected reference position.

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Norfolk, MA, United States of America

Edward F Meihofer