Textiles: weaving – Weft manipulation – Weaving with stationary weft supply
Patent
1981-01-07
1984-08-21
McCarthy, Edward J.
Textiles: weaving
Weft manipulation
Weaving with stationary weft supply
226 97, B03B 4730, B65H 1732
Patent
active
044664699
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to the field of air weft insertion weaving methods and apparatus in which a weft yarn is delivered from a supply to the throat of a weft insertion nozzle which is periodically pressurized to expel therefrom pressurized air or other gaseous propelling medium (the term air being employed here as a general designation for all such media for simplicity's sake) and propel a length of the weft yarn through the nozzle and across the shed of the loom under the driving force of the thus-emitted pressurized air stream, and is concerned more particularly with an improved control system for regulating the actuation of the firing of such nozzle.
BACKGROUND OF THE INVENTION
In application Ser. No. 64,180 of Brouwer et al, filed Aug. 6, 1979, commonly assigned herewith, there is disclosed and claimed a loom and weaving method embodying an air weft insertion system of the type generally defined above in which a pulse of pressurized air of abbreviated duration relative to the duration of the overall weaving cycle of the loom is delivered via a valve from a constantly pressurized air supply chamber to the throat of the weft insertion nozzle directed toward the shed of the loom, which throat is preferably contoured so as to expel such air from its exit opening at a supersonic velocity, the leading end of the weft yarn to be inserted from a weft supply preferably by means of a delivery unit, being disposed within the throat of this nozzle for contact with the air stream passing therethrough and projection thereby into and across the shed of the loom to the opposite side thereof.
This system imposes special and demanding requirements upon the control of the actuation, i.e. opening and closing, of the nozzle valve in order to achieve the air pulse characteristics emitted by the nozzle, including brief duration as well as velocity, needed to impart substantial thrust to the yarn, and in a companion application Ser. No. 64,395 of Brouwer et al, also filed Aug. 6, 1979 and commonly assigned herewith, there is disclosed and claimed a preferred control system for effecting the opening and closing of the nozzle in a manner achieving the required pulse characteristics.
The preferred control system of application Ser. No. 64,395 utilizes a flexible diaphragm as the valve for alternately closing the exit opening of the pressurized air supply chamber and then opening to place the chamber exit opening into communication with the throat passageway of the nozzle wherein the leading weft yarn end is already situated. Advantageously, the air supply chamber is developed as an annular envelope around the nozzle throat passageway so that the exit opening of the chamber is annular and is coterminous and coaxial with an annular inlet opening of the nozzle passageway so that both such openings can be isolated by means of a common diaphragm valve and placed in communication or joined together when the diaphragm opens.
Movement of the diaphragm valve to open and close the supply opening is determined by the application to and release of a control pressure to and from the face of thee diaphragm opposite that face closing the supply chamber opening and preferably nozzle throat openings, as well as such pressure being preferably applied to an annular area of the opposite diaphragm face which area is defined by means of a pilot chamber disposed proximate the opposite diaphragm face. The pilot chamber is alternately placed in communication with a source of pilot or control pressure and the ambient atmosphere, to cause closing and opening of the diaphragm valve, by means of a spool servo valve arrangement which can take several different forms but in all cases incorporates a coordinated pair of rotating spool valves contoured with operative lands and grooves, one governing the pressurization of the pilot chamber and the other governing the de-pressurization or venting of the pilot chamber so that the closing and opening of the diaphragm valve can be carried out independently from a control standpoint. The i
REFERENCES:
patent: 3065769 (1962-11-01), Svaty
patent: 3424359 (1969-01-01), Houle
patent: 3645431 (1972-02-01), Harrison
patent: 3690530 (1972-09-01), Porter
patent: 3706407 (1972-12-01), King
patent: 3782422 (1974-01-01), Vermeulen
patent: 3813900 (1974-06-01), Cook
patent: 4087213 (1978-05-01), Hadama
patent: 4134435 (1979-01-01), Cornellier
Brouwer Charles W.
Wueger Karl W.
Leesona Corporation
McCarthy Edward J.
Norton Burnett W.
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