GB2135702A

GB2135702A - Jet loom nozzles

Info

Publication number: GB2135702A
Application number: GB08401087A
Authority: GB
Inventors: Frantisek Vykydal; Vladimir Kuda; Antonin Bartonek; Jindrich Henzl
Original assignee: VYZK VYVOJOVY USTAV; ZVS Vyzkumnevyvojovy ustav
Current assignee: VYZK VYVOJOVY USTAV; ZVS Vyzkumnevyvojovy ustav
Priority date: 1983-01-26
Filing date: 1984-01-14
Publication date: 1984-09-05
Also published as: CS237611B1; IT1196005B; GB8401087D0; ES8502178A1; ES529129A0; GB2135702B; CH662830A5; IT8419310A0; JPS59181200A; DE3401962A1; FR2539766B1; FR2539766A1

Abstract

A weft inserting device for a jet weaving machine, the purpose of which is to insert different alternately selected weft threads (7) into the warp sheds. This is achieved by the mixing tubes (8) of nozzles (4) being interconnected at the locus of their outlets, preferably at a central exit portion (12) terminating in a single exit opening (13). <IMAGE>

Description

SPECIFICATION Weft inserting device for a jet weaving machine This invention relates to a weft inserting device for a jet weaving machine.

There are known devices for inserting of different, alternately selected weft threads, comprising two or more picking nozzles located intermediate a metering device and the entry into the warp shed, wherein the picking nozzles are mounted rotatably about a fixed point. Such a system of individual nozzles is mounted rotatably about two axes perpendicular to each other. Thus the axes of the exit extremities of the mixing tubes of the picking nozzles assume diverging positions.

The mouths of the individual mixing tubes of the picking nozzles are in adjacent relationship to one another. During the insertion of weft thread by the individual picking nozzles, that picking nozzle which is to insert the weft thread is always positioned in its picking position by turning it about its fulcrum. Upon insertion of the weft thread by the other nozzle, the whole system is turned again in such a way as to bring the picking nozzle into its operative position and oniy then it is possible for the respective weft thread to be inserted. A disadvantage of this device resides in the necessity to turn the system of picking nozzles, since the operative position of the nozzle must be a very exact one, this rotatable arrangement has problems. this arrangement is exacting from the problems.This arrangement is exacting from the manufacture, since the turning mechanism must operate with a high degree of accuracy. After each individual pick the system of picking nozzles must be turned, which affects the reliability thereof.

Moreover, the whole device is mounted on the reed of the weaving machine, which itself performs a reciprocating motion, which further increases the demands made on an absolutely exact operation of the device.

Another known device has a pair of picking nozzles located adjacent the entry portion of the warp shed, these nozzles being in superimposition one to the other in such a way that the exit extremities of the mixing tubes of the picking nozzles are flattened whereby a reduced spacing of their axes is obtained. The device is fixedly mounted and is of a relatively simple construction.

A disadvantage of this arrangement is that during the insertion by means of air stream into the picking channel, the individual weft threads do not lie in one picking axis. Due to diverse picking trajectories which are not identical with the axis of the picking channel, an uncontrolled turbulent whirling occurs upon entering the picking channel.

This may result in an undulatory movement of the weft thread during the insertion, entangiement thereof and subsequent short picks. Another disadvantage of this device is that due to the flattened exit extremity of the mixing tube there occurs an undesirable friction of the weft thread on the lowered walls of the tube.

A weft inserting device according to the present invention comprises at least two picking nozzles, each nozzle having a hollow threading needle and a supply inlet for pressure fluid communicating with a mixing tube, wherein the mixing tubes of the picking nozzles ar interconnected at their outlets so that a single exit opening is formed.

An advantage of the embodiment of the invention is that due to the conjunction of the mixing tubes at a single exit opening an optimum picking trajectory for all weft threads is obtained with a simple construction of the device which is fixedly mounted on the machine frame or on the beat-up mechanism. Thereby a smooth flight of the weft thread is obtained both upon entering the picking channel and during the whole inserting operation, without occurence of the undesirable turbulence. Owing to the simplicity of the entire device a maximum reliability is attained and both the operancy and the adjusting of the device are simplified.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a longitudinal cross-section of a weft inserting device according to the invention mounted on a beat-up mechanism of a jet weaving machine.

Fig. 2 is a longitudinal cross-section at the interconnection of the mixing tubes of the device of Fig. 1.

Fig. 3 is an embodiment according to Fig. 2, further provided with a directing member.

Fig. 4 shows, in longitudinal cross-section, a modification of the device of Fig. 1 in which the mixing tubes are connected to a drilled head providing suitable nozzle channels according to the invention.

The weft inserting device is secured in a jet weaving machine between a thread metering device and the entry side of the warp shed in a Ushaped holder 1. At the left hand side of the holder are fastened, by means of screws 2, individual bodies 3 of a combination of two picking nozzles, 4, of which more may be provided. In each body 3 a hollow threading needle 5 is fixed having a threading inlet opening 6 for a weft thread 7. The exit portion of the threading needle S opens into the bore of a mixing tube 8 secured in the body 3 downstream of the threading needle 5. The threading needle 5 is secured in the body 3 by means of a screw cap 9 mounted on the outer thread of the extremity of the body 3.In the middle portion of each threading needle 5 is provided a circumferential by-pass chamber 10 into which discharge pressure fluid from a supply inlet 11 which is attached to each individual body 3. The axes of the individual picking nozzles 4 are situated convergently so that the mixing tubes 8 intersect each other at the locus of their downstream ends or mouths. This means that the mixing tubes 8 are interconnected at their exit sides for the weft threads in such a way as to form a single central exit portion 12 terminating in a single common exit opening 13. By means of a fastening member 14 a socket 1 5 is fastened from the outside on the central exit portion 12.The socket terminates in a directing portion 1 6 provided with a clear unobstructed hole 17, the axis of which coincides with the axis of the warp shed and which is parallel with the longitudinal axis of the reed of the beat-up mechanism 1 8. By means of its circumferential portion, the socket 15, and consequently also the exist portion 12, are secured in the right hand portion of the holder 1, the latter being secured to the beat-up mechanism 1 8. The socket 1 5 may be secured variably on the nozzles 4.

Positioned in front of the exit opening 13 of the device is the warp shed formed by warp threads 1 9. Upon admission of the pressure fluid through a distribution valve, not shown, and the supply inlet 11 into the by-pass chamber 10 of one of the picking nozzles 4, the fluid is distributed about the hollow threading needle 5 into the mixing tube 8. Through the threading inlet opening 6 of the hollow threading needle 5 the weft thread 7 is passed into the mixing tube 8. The weft thread 7 is entrained by the flow of the pressure fluid in the mixing tube 8 and carried as far as the central exit portion 1 2 wherein it passes through the clear hole 1 7 of the socket 1 5.At this point a final directing of the trajectory of the weft thread 7 and the insertion thereof into the warp shed formed by the warp threads 1 9 takes place.

Thereafter the weft thread 7 is propelled through the warp threads 1 9 and is cut off by scissors, not shown, at the entry point of the wrap shed. The free end of the weft thread 7 is retracted into the picking device, and this as far as rearwardly of the central exist portion 1 2.

During the insertion of the weft thread 7, and thus under full working pressure of the fluid in one of the mixing tubes 8, it is advantageous to supply an auxiliary pressure of the fluid into the other mixing tube 8, whereby the performance of the device is increased in the central exit portion 12 and directing of the weft thread 7 into the warp shed is improved.

The machine in which the inserting device is used may be similar to that described and shown in our copending patent application (corresponding to Czechoslovak Patent Application No. PV3398-83 of 16 May 1983) which also described a suitable metering device.

Claims

1. A weft inserting device for a jet weaving machine, comprising at least two picking nozzles, each nozzle having a hollow threading needle and a supply inlet for pressure fluid communicating with a mixing tube wherein the mixing tubes of the picking nozzles are interconnected at their outlets so that a single exit opening is formed.

2. A device as claimed in claim 1, wherein the exit opening is formed in a central exit portion of the device of the picking nozzles, which exit portion extends towards its downstream end to a directing portion provided with an unobstructed clear hole.

3. A device as claimed in claim 2, wherein the directing portion is formed by a socket secured variably on the picking nozzles.

4. A jet weaving machine having the device as claimed in any one of claims 1 to 3.

5. A machine as claimed in claim 4 wherein the device is mounted between a thread metering device and the entry side of the warp shed.

6. A machine as claimed in claim 4 or 5 wherein the axis of the exit opening is parallel to the longitudinal axis of the reed of the beat-up mechanism of the machine.

7. A weft inserting device for a jet weaving machine substantially as described with reference to the accompanying drawings.

8. A jet weaving machine substantialiy as described with reference to the accompanying drawings.