Web tension control for high-speed web handling equipment

A method of web tension control in high speed web handling equipment of the type having a core support upon which the core of a web feed roll is rotatably mounted, a variable torque brake associated with the core exhibiting a substantially constant coefficient of friction at all web speeds and a dancer roller positioned to engage the web and movable thereby in accordance with changes in the web tension, the method comprising the steps of sensing the position of the dancer roller relative to a preselected position thereof, generating a correction signal in accordance with the difference between the sensed position of the dancer roller and the preselected position, processing the correction signal, and varying the brake torque in accordance with the processed signal, wherein the step of processing the correction signal comprises generating a first signal proportioned to the correction signal, generating a second signal proportioned to a derivative of the correction signal and combining the first and second signals to form the processed signal, and wherein the step of processing the correction signal further comprises determining the diameter of feed roll, generating a signal proportional to the diameter of the feed roll, cubing the generated signal and combining the cubed generated signal with the processed signal.

A method of web tension control in high speed web handling equipment of the type having movable core support upon which the cores of a feed roll and a new roll are respectively rotatably mounted, variable torque brakes associated with each of the cores exhibiting a substantially constant coefficient of friction at all web speeds and a paster carriage movable relative to the support having a rotatable paster roll and cutting means mounted thereon, the method comprising the steps of splicing the web from the new roll onto the web from the feed roll and maintaining the tension on the web at a substantially constant level throughout the splicing process, wherein the step of splicing comprises positioning the support in pasting position, moving the carriage such that the paster roll engages the web, pasting the web from the new roll onto the web from the feed roll, cutting the web from the feed roll and moving the support to place the new roll into running position and wherein the step of maintaining web tension comprises the steps of sensing the surface speed of the feed roll, driving the new roll at a speed substantially equal to the sensed speed and simultaneously with cutting, adjusting the torque setting on the brake associated with the new roll in accordance with the diameter of the new roll.

A method of web tension control in high speed web handling equipment of the type having a core support upon which a feed roll and a new roll are rotatably mounted, a variable torque brake associated with each core exhibiting a substantially constant coefficient of friction through all speeds of the web and means for splicing the web from the new roll onto the web from the feed roll, the method comprising the step of setting the brake torque on the brake associated with the new roll to a value dependent upon the diameter of the new roll simultaneously with the splicing of the web from the new roll with the web from the feed roll.

A method of web tension control in high speed web handling equipment of the type having a core support upon which a web feed roll is rotatably mounted, a variable torque brake associated with the core exhibiting a substantially constant coefficient of friction at all web speeds and a dancer roller engageable with the web and movable thereby, the method comprising the steps of determing the initial diameter of the feed roll, generating a first signal in accordance with the initial diameter of the feed roll, generating a second signal in accordance with changes in the feed roll diameter, combining the first and second signals and varying the brake torque in accordance with the combined signal such that changes in the feed roll diameter are compensated for as the web is removed therefrom.

A method of web tension control in high speed web handling equipment of the type having a core support upon which the core of a web feed roll is mounted, and a variable torque brake associated with the core exhibiting a substantially constant coefficient of friction through all web speeds, the method comprising the steps of setting web tension, determining the diameter of the feed roll, generating a signal proportional to the determined diameter multiplied by the tension setting, cubing the signal and adjusting the torque on the brake in accordance with the cubed signal.

A method of web tension control in high speed web handling equipment of the type having a core support upon which the core of a web feed roll is mounted, a variable torque brake associated with the core exhibiting a substantially constant coefficient of friction at all speeds of the web and means for generating a signal representative of variations in web tension, the method comprising the steps of generating a signal based on the effective diameter of the feed roll, processing the web tension signal, combining the processed web tension signal and the diameter signal to form a brake regulating signal and varying the brake torque in accordance with the brake regulating signal.