Web threading system

Apparatus for directing the tail of a moving web of flexible material to a predetermined location along an alternate web path spaced from the normal running path of said web and leading to said predetermined location comprising:

• a first apparatus segment disposed out of the normal running path of said web and having an open-ended, open-topped channel member including a first wall element defining a first web transfer surface along said alternate web path and open to the atmosphere with a web entry end and a web exit end and a first Coanda nozzle disposed at the web entry end to direct a gaseous flow in said channel member along said first web transfer surface from said web entry end to said web exit end;
• and
• a second apparatus segment having an open-ended, open-topped channel member including a second wall element defining a second web transfer surface along said alternate web path and open to the atmosphere with a web entry end and a web exit end and a second Coanda nozzle disposed at the second web transfer surface entry end to direct a gaseous flow in said second segment channel member from the web entry to the web exit end thereof, said first segment being directed toward said second segment and spaced therefrom a substantial distance whereby the web tail is projected across an open space between segments along said alternate web path toward said second Coanda nozzle by said first segment and is engaged and entrained by the gaseous flow in the second segment in the vicinity of said second Coanda nozzle and propelled further along said alternate web path, and whereby a substantial portion of the gaseous flow from the first segment does not reach said second segment.

A method of directing the tail of a moving web of flexible material to a predetermined location comprising the steps of:

• positioning a flow path for gas adjacent to said web tail;
• flowing a pressurized gas through at least one restricted opening communicating with said gas flow path in a direction differing from the direction of said gas flow path;
• changing the direction of the pressurized gas after it flows through said restricted opening through utilization of the Coanda effect so that it flows along the first gas flow path;
• entraining ambient air with said pressurized gas so that a combined gaseous flow of pressurized gas and entrained ambient air flows along the gas flow path;
• placing the web tail into engagement with the gaseous flow whereby the tail is entrained and propelled thereby along the gas flow path;
• and
• diverting the direction of a substantial portion of the gaseous flow away from said web tail through utilization of the Coanda effect while physically restraining said web tail in such a manner that the web tail is prevented from moving with said substantial portion of said gaseous flow but is not prevented from moving toward said predetermined location.

The method of directing the tail of a moving web of flexible material to a predetermined location along an alternate web path spaced from the normal running path of said web and leading to said predetermined location comprising the steps of:

• positioning a first flow path for gas adjacent to said web tail and along said alternate path;
• flowing a pressurized gas through at least one restricted opening of a Coanda nozzle communicating with said first flow path so tat a gaseous flow is directed along said first flow path;
• positioning a second flow path for gas along said alternate path between said first flow path for gas and said predetermined location;
• flowing a pressurized gas through at least one restricted opening of a second Coanda nozzle communicating with said second flow path so that a gaseous flow is directed along said second flow path;
• directing said fist flow path toward said second flow path while maintaining a predetermined distance therebetween of sufficient magnitude such that a substantial portion of the gaseous flow from the first flow path is dissipated before it reaches the second flow path;
• and
• bringing the web tail and the gaseous flow along said first flow path into operative engagement so that the tail is projected across said predetermined distance toward said second Coanda nozzle and is entrained by the gaseous flow along the second flow path in the vicinity of said second Coanda nozzle and advanced thereby along the alternate web path.