WEFT YARN INSERTION CHANNEL

Abstract: A guide tooth (11) for a weft insertion channel (10), the guide tooth (11) in cross-section defining a continuously bounded opening (18) for weft yarn insertion, the guide tooth (11) including weft yarn exit mouth which is closed during weft insertion and which permits the weft yarn to pass therethrough on beat-up. The guide tooth (11) 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 (11) is a one piece plastics moulding comprising a pair of arms (14, 15) which are hingedly connected together.

Description: WEFT YARN INSERTION CHANNEL The present invention relates to a weft yarn insertion channel for use in a fluid jet weaving loom. 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. 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. 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. A general object of the present invention is to provide a weft insertion channel ' which fulfils both of the above requirements. 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 we'ft yarn exit mouth which is closed during weft insertion and which permits the weft yarn to pass therethrough on beat-up. 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. 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. 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. 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_ 5 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 I Q 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 ^ l6. Lower portions 14£ and 15 each have a widened portion 14d_, 15d respectively which abut against similar 15 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 2o position individual teeth relative to one another. Portions 14d_ are clamped to the base of reed 12 and portions 15* 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 25 illustrated in Figure 6 portions 14d_, 15d_ are provided with apertures 14e_, 15 through which stiff rods e.g. made of steel pass in order to secure adjacent teeth together. Preferably teeth 11 are arranged in groups 25 so that all arms 15 of teeth 11 in one group move in unison 30 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 of the teeth in the neighbouring group. Due to inherent bias within web 16 the terminal end 5 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 ay 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_, 15fc> 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. 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 r the smaller predetermined bias being such as to maintain contact betwen faces 14b_, 15b_ but permit the weft yarn to part the faces 14b, 15b_ to exit from teeth 11. 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. 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 3 to provide an auxiliary blast of air to carry the leading end of the weft • yarn through a particular group 25 of teeth. 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. After the leading end of the weft yarn 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 14b_, 15fc> on all teeth are spaced apart ready for easy exit of the weft yarn during beat-up. Alternatively as illustrated in Figure 7 the biasing means 26' may be mounted on the reed shaft 50 for movement 5 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, 10 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 15 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. When the reed shaft 50 moves away from its beat-up position, the lower end of resilient member 60 contacts stop 20 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 25 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 0 plastics. f OMPl

Claims: 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 5 and which permits the weft yarn to pass therethrough on beat-up. 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 10beat-up. Preferably each guide tooth is a one piece plastics moulding comprising a pair of arms which are hingedly connected together. 2. A guide tooth according to Claim 1 including two arms 15 which are spaced apart and a resilient connection for joining the arms together to define a hinged connection. 3. A guide tooth according to Claim 2 wherein the arms and resilient connection are integrally formed. ' 20 4. A guide tooth according to Claim 2 or 3 wherein the resilient connection biases the arms apart to define said mout . 255. A weft insertion channel including a plurality of guide teeth according to Claim 4 and biasing means for closing said mout . 6. A weft insertion channel according to Claim 5 wherein 30 the biasing means applies a constant bias to close said mouth which bias is slightly greater than the bias of said resilient connection. 7. A weft insertion channel according to Claim 5 wherein 35 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. 8. A weft insertion channel according to Claim 5, 6 or 7 wherein the guide teeth are arranged in groups of teeth, each group being acted upon by a respective biasing means. 9. A weaving loom including a plurality of guide teeth according to any of Claims 1 to 4. 10. A weaving loom including a weft insertion channel according to any of Claims 5 to 8.

Inventors: GRIFFITH JOHN DALTON, GRIFFITH, JOHN, DALTON
Applicants: BONAS MACHINE CO, BONAS MACHINE COMPANY LIMITED
Application year: 1983
Main classification: D03D47
IPC codes: D03D47