| 摘要 |
A method and system for preventing damage to a movable dancer assembly in a festoon upon the breakage of the running web that runs through the festoon. During normal running of the web, the vertical position of the dancer assembly, in the festoon and vis-à-vis the fixed entry and exit idlers of the festoon, is controlled by a dancer tensioning cylinder assembly that includes a cylinder and a piston which is connected with the dancer assembly and which is movable in the cylinder in response to pressurized air in a first portion of the cylinder and applied to a first surface of the piston. Upon the breaking of the running web, air pressure is permitted to increase in a second portion of the cylinder and is applied to the second, opposite surface of the piston until the pressure of the air in the first and second positions becomes equal. After a preselected delay after the running web breaks, the pressurized air in the first and second portions of the cylinder is bled from the cylinder.
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