WEFT YARN INSERTION CHANNEL

Description

[0001] The present invention relates to a weft yarn insertion channel for use in a fluid jet weaving loom.

[0002] It is known in fluid weaving looms to provide a weft insertion channel composed of a plurality of individual guide teeth, the channel extending across the warp sheet and a stream of fluid, preferably air, is directed along the channel to carry the weft yarn across the warp sheet.

[0003] The guide teeth have to perform two main functions viz., (1) they have to guide the air flow along the channel so as to carry the weft yarn therealong without it jumping out of the channel and (2) they have to permit easy exit of the inserted weft yarn on beat-up in the weaving cycle.

[0004] These two requirements tend to conflict in that the second requirement is ideally achieved with a guide tooth having a permanently open weft yarn exit mouth but such a mouth creates problems in maintaining the weft yarn in the channel during weft insertion and so makes the first requirement more difficult to achieve.

[0005] Various proposals have been made heretofore. For example U.S. Patent 3742973 and French Patent 2370811 both provide guide teeth having continuously bounded insertion openings wherein the exit mouth is covered by a resilient lip. A main disadvantage with such a construction is difficulty of manufacture due to the provision of the resilient tip. In addition, it is impossible with such a construction to open the exit mouth by mechanical means so that in all applications the weft yarn must force its way past the resilient lip.

[0006] French Patent 1452576 and U.K. Patent 2072719 provide alternative constructions of guide teeth for providing a weft insertion channel which during the insertion cycle provides a continuously bounded channel and which on beat up define exit mouth openings through which the weft yarn can escape.

[0007] According to one aspect of the present invention there is provided a guide tooth for a weft insertion channel, the guide tooth in cross-section defining a continuously bounded opening for weft yarn insertion, the guide tooth including a weft yarn exit mouth which is closed during weft insertion and which permits the weft yarn to pass therethrough on beat-up characterised in that the guide tooth includes two arms which are joined together by a resilient connection which defines a hinged connection and are shaped to define said continuously bounded opening, the arms being movable about the hinged connection to open and close said exit mouth. The guide tooth may be constructed so that the weft yarn opens the exit mouth during beat-up or may be constructed so that the mouth is opened after weft yarn insertion to provide a gap through which the yarn passes on beat-up. Preferably each guide tooth is a one piece plastics moulding comprising a pair of arms which are hingedly connected together.

[0008] According to another aspect of the present invention there is provided a weft yarn insertion channel comprising a plurality of guide teeth as defined above, the guide teeth being arranged in groups of teeth so that the channel is defined by a plurality of side by side groups of said teeth, the teeth in each group being connected so as to move in unison for opening/closing of the weft yarn exit mouth. Preferably the groups of teeth are arranged so that the weft yarn exit mouths are normally open, actuation means being provided to act on successive groups to close the weft yarn exit mouths of teeth in each group as the leading end of the weft yarn passes therethrough during insertion.

[0009] Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which:

Figure 1 is an end view of a weft insertion channel according to the present invention shown in situ;

Figure 2 is a front view of the guide channel shown in Figure 1;

Figure 3 is a schematic illustration similar to Figure 2 showing the guide channel extending across the warp sheet; and

Figure 4 is an end view similar to Figure 1 of another embodiment according to the present invention;

Figure 5 is a perspective view of a guide tooth according to the present invention;

Figure 6 is a perspective view of another guide tooth according to the present invention; and

Figure 7 is an end view similar to Figure 1 of another embodiment according to the present invention.

[0010] The weft insertion channel 10 is composed of individual guide teeth 11 secured to the base of the reed 12 so as to be in front of the reed. Each tooth 11 is arranged in abutting relationship with a neighbouring tooth so that collectively they form a channel extending across the warp sheet. Each tooth 11 is preferably formed in one piece from a plastics material and is conveniently injection moulded. Each tooth 11 has a pair of arms 14, 15 which are connected via a web 16. The web 16 provides a flexible connection between arms 14, 15 so as to define a hinge. The upper portions 14a, 15a of arms 14 and 15 are shaped so as to define together with web 16 an opening 18 through which compressed air is directed for carrying weft yarn across the warp shed. The upper portions 14a, 15a have terminal end faces 14b, 15b respectively which abut against one another but which on separation define a gap therebetween through which the weft yarn can exit during beat-up. The arms 14, 15 have lower portions 14c, 15c respectively which extend downwardly below web 16. Lower portions 14c and 15c each have a widened portion 14d, 15d respectively which abut against similar portions on neighbouring teeth and thereby serve to space the upper portions of the teeth from one another. In the embodiment illustrated in Figure 5 each portion 14d, 15d has projections and recesses for co-operation with recesses and projections on the neighbouring tooth so as to accurately position individual teeth relative to one another. Portions 14d are clamped to the base of reed 12 and portions 15d are freely mounted. Since portions 15d interact with one another they move in unison and restrain lateral twisting movements between arms 14, 15 of individual teeth. In the embodiment illustrated in Figure 6 portions 14d, 15d are provided with apertures 14e, 15e through which stiff rods e.g. made of steel pass in order to secure adjacent teeth together.

[0011] Preferably teeth 11 are arranged in groups 25 so that all arms 15 of teeth 11 in one group move in unison independently of the arms 15 of teeth 11 in other groups. Accordingly the portions 15d of terminal teeth in each group slidingly abut the neighbouring portion 15d ofthe teeth in the neighbouring group.

[0012] Due to inherent bias within web 16 the terminal end faces 14b, 15b are normally spaced apart and so biasing means 26 are provided to operate on each group 25 to bias faces 14b, 15b into contact. As seen in Figure 1 the biasing means may be arranged to provide a permanent bias which is sufficient to overcome the inherent bias in web 16 and so maintain faces 14b, 15b in contact but which permit the weft yarn to part the faces 14b, 15b to exit from the teeth on beat-up. To assist the yarn to exit between faces 14b, 15b inclined faces may be provided to create a lead-in for the weft yarn.

[0013] Alternatively, as seen in Figure 4, the biasing means 26' may be arranged to provide a variation in the biasing force dependent on the cycle of the weaving loom. In this case the biasing means 26' may be arranged to provide a greater bias during weft insertion and a smaller predetermined bias during beat-up, the smaller predetermined bias being such as to maintain contact between faces 14b, 15b but permit the weft yarn to part the faces 14b, 15b to exit from teeth 11.

[0014] Alternatively, the biasing means may be arranged to provide a biasing force during weft insertion only so that at other times the abutting faces 14b, 15b are allowed to part to provide an open mouth for exit of the inserted weft yarn.

[0015] In this respect, advantageously the biasing means 26' for each group are mounted on a cam follower 40 which actuates auxiliary air nozzles associated with each group 25 of guide teeth. In use, cam followers 40 are actuated in succession from left to right in Figure 3to provide an auxiliary blast of airto carry the leading end of the weft yarn through a particular group 25 of teeth.

[0016] Accordingly simultaneously with operating the auxiliary air nozzle associated with a particular group 25 the cam follower 40 moves the biasing means 26'to move arms 15 to bring faces 14b, 15b into contact for that particular group of teeth.

[0017] After the leading end oftheweftyarn has passed through the particular group the cam follower 40 is moved to close-off supply of air to that particular group and so simultaneously permits faces 14b and 15b to part. Accordingly, after weft insertion has been completed, faces 146,156 on all teeth are spaced apart ready for easy exit of the weft yarn during beat-up.

[0018] Alternatively as illustrated in Figure 7 the biasing means 26' may be mounted on the reed shaft 50 for movement therewith so that when the reed shaft moves away from its beat-up position the biasing means 26' are operated to close the weft yarn exit gap in readiness for insertion of the weft yarn. The biasing means 26' illustrated in Figure 7 basically comprises an elongate resilient member 60, preferably in the form of a leaf spring, which at one end co-operates with arms 15 of a respective group of teeth and co-operates at its other end with an adjustable stop 61 which is slidably mounted on the loom frame. The member 60 is secured to the reed shaft 50 via a further resilient member 64. Resilient member 64 is preferably also a leaf spring which is secured at one end to the reed shaft 50 and at the other end to resilient member 60.

[0019] When the reed shaft 50 moves away from its beat-up position, the lower end of resilient member 60 contacts stop 61 and is thereby deflected. Such deflection causes deflection of member 64 and consequently deflection of the upper part of member 60 which then biases arms 15 to close. The amount of bias imposed on arms 15 is conveniently controlled and adjusted by appropriate setting of the position of the adjustable stop 61. By moving stop 61 to the right as seen in Figure 7 the lower end of member 60 is deflected by a greater amount thereby increasing the amount of bias. The position of end stop 61 is adjusted and maintained by a bolt 67. Conveniently the stop 61 is made of plastics.

Claims

1. A guide tooth for a weft insertion channel, the guide tooth in cross-section defining a continuously bounded opening for weft yarn insertion, the guide tooth including a weft yarn exit mouth which is closed during weft insertion and which permits the weft yarn to pass therethrough on beat-up characterised in that the guide tooth includes two arms (14, 15) which are joined together by a resilient connection (16) which defines a hinged connection and are shaped to define said continuously bounded opening, the arms being movable about the hinged connection to open and close said exit mouth.

2. A guide tooth according to Claim 1 wherein the arms (14,15) and resilient connection (16) are integrally formed.

3. A guide tooth according to Claim 1 or 2 wherein the resilient connection biases the arms apart to define said mouth.

4. A weft insertion channel including a plurality of guide teeth according to Claim 3 and biasing means (26) for closing said mouth.

5. A weft insertion channel according to Claim 4 wherein the biasing means applies a constant bias to close said mouth which bias is slightly greater than the bias of said resilient connection.

6. A weft insertion channel according to Claim 4 wherein said biasing means applies an intermittent bias for closing said mouth for weft insertion and for permitting said mouth to open under the bias of said resilient connection during beat-up.

7. A weft insertion channel according to Claim 4, 5 or 6 wherein the guide teeth are arranged in groups (25) of teeth, each group being acted upon by a respective biasing means.

8. A weft insertion channel according to Claim 7 wherein the groups of teeth are arranged so that the weft yarn exit mouths are normally open, actuation means (40) being provided to act on successive groups to close the weft yarn exit mouths of teeth in each group as the leading end of the weft yarn passes therethrough during insertion.

9. A weaving loom including a plurality of guide teeth according to any of Claims 1 to 3.

10. A weaving loom including a weft insertion channel according to any of Claims 4 to 8.

Ansprüche

1. Ein Führungszahn für einen Schußeintragkanal, welcher Führungszahn im Querschnitt eine kontinuierlich begrenzte Öffnung für den Schußgarneintrag begrenzt, welcher Führungszahn eine Schußgarnaustrittsmündung aufweist, die während des Schußeintrags geschlossen ist und den Durchtritt des Schußgarnes beim Anschlag ermöglicht, dadurch gekennzeichnet, daß der Führungszahn zwei Arme (14, 15) umfaßt, die durch eine federnde Verbindung (16) miteinander verbunden sind, welche eine gelenkige Verbindung bildet, und die so geformt sind, daß sie die genannte kontinuierlich begrenzte Öffnung definieren, welche Arme um die gelenkige Verbindung beweglich sind zum Öffnen und Schließen der genannten Austrittsmündung.

2. Führungszahn nach Anspruch 1, bei dem die Arme (14, 15) und die federnde Verbindung (16) einstückig ausgebildet sind.

3. Führungszahn nach Anspruch 1 oder 2, bei dem die federnde Verbindung die Arme in Abspreizrichtung vorspannt zum Bilden der genannten Mündung.

4. Ein Schußeintragkanal, umfassend eine Mehrzahl von Führungszähnen nach Anspruch 3 und Vorspannmittel (26) für das Schließen der genannten Mündung.

5. Schußeintragskanal nach Anspruch 4, bei dem die Vorspannmittel eine konstante Vorspannung zum Schließen der genannten Mündung aufbringen, welche Vorspannung geringfügig größer ist als die Vorspannung der genannten federnden Verbindung.

6. Schußeintragskanal nach Anspruch 4, bei dem die genannten Vorspannmittel eine intermittierende Vorspannung aufbringen zum Schließen der genannten Mündung für den Schußeintrag und für die Ermöglichung der Mündungsöffnung unter der Vorspannung der genannten federnden Verbindung während des Anschlags.

7. Schußeintragskanal nach Anspruch 4, 5 oder 6, bei dem die Führungszähne in Gruppen (25) von Zähnen angeordnet sind, wobei auf jede Gruppe von jeweils zugeordneten Vorspannmitteln eingewirkt wird.

8. Schußeintragskanal nach Anspruch 7, bei dem die Gruppen von Zähnen so angeordnet sind, daß die Schußgarnaustrittsmündung normalerweise offen ist, wobei Betätigungsmittel (40) vorgesehen sind zum Einwirken auf aufeinanderfolgende Gruppen zum Schließen der Schußgarnaustrittsmündungen der Zähne in jeder Gruppe, wenn das führende Ende des Schußgarns beim Eintrag hindurchpassiert.

9. Ein Webstuhl mit einer Mehrzahl von Führungszähnen nach einem der Ansprüche 1 bis 3.

10. Ein Webstuhl mit einem Schußeintragskanal nach einem der Ansprüche 4 bis 8.

Revendications

1. Dent de guidage pour un canal d'insertion de duite, la dent de guidage définissant, en section transversale, une ouverture délimitée de façon continue pour l'insertion d'un fil de trame, la dent de guidage présentant une embouchure de sortie du fil de trame qui est fermée pendant l'insertion d'une duite et qui permet au fil de trame d'y passer lors du battage, caractérisée en ce que la dent de guidage comprend deux bras (14, 15) qui sont reliés l'un à l'autre par une liaison élastique (16) qui définit une liaison articulée, et qui sont configurés pour définir ladite ouverture délimitée de façon continue, les bras étant mobiles autour de la liaison articulée pour ouvrir et fermer ladite embouchure de sortie.

2. Dent de guidage selon la revendication 1, dans laquelle les bras (14,15) et la liaison élastique (16) sont réalisés d'une seule pièce.

3. Dent de guidage selon la revendication 1 ou 2, dans laquelle la liaison élastique rappelle les bras à l'écart l'un de l'autre pour définir ladite embouchure.

4. Canal d'insertion de duite comprenant plusieurs dents de guidage selon la revendication 3 et des moyens de rappel (26) destinés à fermer ladite embouchure.

5. Canal d'insertion de duite selon la revendication 4, dans lequel les moyens de rappel appliquent un rappel constant pour fermer ladite embouchure, lequel rappel est légèrement supérieur au rappel de ladite liaison élastique.

6. Canal d'insertion de duite selon la revendication 4, dans lequel lesdits moyens de rappel appliquent un rappel intermittent pour fermer ladite embouchure pour l'insertion d'une duite et pour permettre à ladite embouchure de s'ouvrir sous le rappel de ladite liaison élastique pendant le battage.

7. Canal d'insertion de duite selon la revendication 4, ou 6, dans lequel les dents de guidage sont agencées en groupes (25) de dents, un moyen respectif de rappel agissant sur chaque groupe.

8. Canal d'insertion de duite selon la revendication 7, dans lequel les groupes de dents sont agencés de façon que les embouchures de sortie du fil de trame soient normalement ouvertes, des moyens d'actionnement (40) étant prévus pour agir sur des groupes successifs afin de fermer les embouchures de sortie de fil de trame des dents de chaque groupe lorsque le bout avant du fil de trame y passe pendant l'insertion.

9. Métier à tisser comprenant plusieurs dents de guidage selon l'une quelconque des revendications 1 à 3.

10. Métier à tisser comprenant un canal d'insertion de duite selon l'une quelconque des revendications 4 à 8.

Drawing