Patent ID: 6216934
Filing Date: 2001-04-17
Classification: B65H

Abstract:
In a method for controlling the speed and tension of a running web being unwound from a rotating roll and being run through a festoon and then to a web-using production process; where the festoon includes a relatively fixed entry idler, a relatively fixed exit idler and a vertically movable dancer about which the running web runs; where the dancer may be moved vertically, relatively with respect to the idlers, depending on the amount or quantity of running web being stored in the festoon; where the dancer is connected with a dancer tensioning cylinder assembly that is adapted to urge the dancer vertically against the force of the running web running over the dancer and that includes a cylinder having a first end and a second end, and a piston, which is movable within the cylinder, which is connected with the dancer, and which has a first surface facing the first end of the cylinder, and a second surface facing the second end of the cylinder; where a first portion of the cylinder is defined between the first end of the cylinder and the first surface of the piston; where a second portion of the cylinder is defined between the second end of the cylinder and the second surface of the piston; where a source of air under pressure supplies pressurized air to the first portion of the cylinder; where a regulator regulates the pressure of the pressurized air supplied to the first portion of the cylinder; and where the piston is movable within the cylinder in response to the air pressure being applied to the first portion of the cylinder and acting on the first surface of the piston, the improvement comprising steps of:causing the pressure of the air in the second portion of the cylinder to increase after a break in the running web has occurred so that the pressure of the air in the second portion of the cylinder slows and then stops movement of the piston toward the second end of the cylinder; andbleeding the pressurized air in second portion of the cylinder from the second portion of the cylinder after a preselected delay after the break in the running web.