The present invention relates to a weft yarn insertion assembly for use in a weaving loom.

Weaving looms are known wherein weft yarn is conveyed across 'the warp shed using a stream of fluid which is usually 5 guided by a channel defined by a plurality of teeth.

It is known to provide a main fluid nozzle at one side of the warp sheet for projecting the weft yarn and two types of nozzle are commonly used. The first type of nozzle is mounted on the loom frame so as to be stationary thereby enabling the 10 inlet mouth of the nozzle to be closely spaced to weft yarn feed means to provide optimum acceleration of the weft yarn at the beginning of weft insertion.

Normally, the guide channel is mounted at the base of the reed and so is positioned in the warp shed to receive weft 15 yarn. If the insertion nozzle is fixedly mounted on the frame of the loom the channel only registers with the outlet of the nozzle at one position, viz. the dwell position of the reed and so weft insertion can only take place at this position.

In order to decrease the time of weft insertion a second 20. type of nozzle is known which is movable in unison with the reed so that weft insertion can begin as soon as the channel enters the warp shed. Unfortunately this type of nozzle has two drawbacks. Firstly since the reed undergoes a relatively large displacement the outlet of the nozzle also is displaced 5 with the reed which causes a relatively large displacement of the inlet and accordingly it is not possible to closely space the inlet of the nozzle to the weft yarn feed means. Thus with this system it is not possible to achieve optimumn acceleration of the weft yarn. The second drawback is that since the outlet 0 moves in unison with the reed, at beat-up the outlet of the nozzle is positioned below the warp sheet by a relatively large distance which can result in weft yarn breakage.

It is a general object of the present invention to provide a weft insertion nozzle which possesses the advantages of the 5

OMPI

above types of nozzle and yet overcomes the disadvantages.

According to one aspect of the present invention there is provided a weft yarn insertion nozzle having an elongate tube along which fluid flows for weft insertion, the tube having a weft yarn inlet at one end and a weft yarn outlet at the other end, the tube being mounted adjacent its inlet end to the frame via a first mounting means which permits angular displacement of the tube, the tube adjacent its outlet end being movably mounted on the reed beat-up shaft via a second mounting means so that the outlet during movement of the reed is displaced relative to the loom frame by a smaller amount than the reed.

Accordingly, the outlet of the nozzle during beat-up does not undergo as large a displacement as the prior art type nozzle and so causes a small displacement of the inlet of the nozzle. Thus the inlet can be positioned close to the feed means for the weft yarn to achieve optimum acceleration of the weft yarn.

Various aspects of the present invention will hereafter be described with reference to the accompanying drawings, in whic :-

Figure 1 is a schematic side view of a weft insertion nozzle according to the present invention shown in situ on part of a loom; and

Figure 2 is a schematic end view of the nozzle shown in Figure 1.

In Figure 1 a nozzle 10 according to the present invention is shown having a weft yarn inlet end 11 and a weft yarn outlet end 12.

The nozzle 10 includes a rigid tube 14 which carries an air chamber 15 adjacent the inlet end 11 and which introduces air into tube 14 for projecting weft yarn from left to right as shown in the drawings. Weft yarn feed means 13 for supplying weft yarn 13a_ is schematically shown positioned adjacent the inlet end 11. A suitable feed means 13 as that disclosed in our co-pending U.K. patent application 8121646.

The nozzle 10 is mounted adjacent its inlet end 11 to a portion 16 of the loom frame via mounting means 17 in the form

of a flexible strip 18 which permits angular displacement of the nozzle but prevents rotation of the nozzle about its axis. The outlet end 12 is mounted onto the loom shaft 19 which carries the beat-up reed 20 (Figure 2) via mounting means 22 in the form of a radial arm 23 projecting from shaft 19 and a pivotal connection 24 between the arm 23 and tube 14. The pivotal' connection 24 includes a stub shaft 30 projecting from a bracket 32 and which is rotatably received in a ball and socket type bearing 33 mounted in arm 23. The bracket 32 is rigidly fastened to the tube 14, for example, by a split clamp and screw 36.

The mounting of the tube 14 is chosen so that at a desired range of positions during movement of the reed and associated weft guide channel 38 through the warp shed there is sufficient register between the channel 38 and the outlet of the tube 14 to enable weft yarn to be directed along the channel 38.

Additioanlly the mounting is chosen so that, as illustrated in Figure 2, as the reed moves from its dwell position (full lines) to its beat-up position (broken lines) the line R~ and R-' remain parallel. Thus the centre of the front of the tube 14 moves to a position 14'. If the nozzle had been fixed to the reed assembly, then the tube end 14 would have travelled to position 50, which as can be seen is both further forward and lower down from the fell point 51 of the fabric 13.

Position 14' can be chosen by selecting the position of the pivot 33 with respect to the main reed assembly pivot axis 52. For example lowering pivot 33 closer to pivotal axis 52 will reduce the amount position 14* lies in front of the fell point 51, and moving pivot 33 to the left further behind the reed, reduces the amount position 14' lies below the fell point 51.