US3672406A - Method for transporting a weft thread through a shed and loom for performing said method - Google Patents

Abstract

A method for transporting a weft thread through a shed using one or more jet nozzles for a flowing transport fluid characterized in that the jet nozzle is fed by a cyclically varying quantity of transport fluid.

Description

nited States Patent 51 June 27,1972

Vermeulen METHOD FOR TRANSPORTING A WEF T THREAD THROUGH A SHED AND LOOM FOR PERFORMING SAID METHOD Inventor: Geert Jan Vermeulen, Beethovenlaan 34,

Deurne, Netherlands Filed: Oct. 22, 1970 Appl. No.: 83,175

Foreign Application Priority Data Net 22, 1969 Netherlands ..69l5973 U..a'. CI 139/127 P, D03d/47/30 Field of Search ..139/122, 1, 127

[56] References Cited UNITED STATES PATENTS 3,229,725 1/1966 Saito ..l39/127 P 2,936,002 5/1960 Opletal et al. 139/127 P Primary Examiner-Henry S. Jaudon AttorneyMarshall & Yeasting [57] ABSTRACT A method for transporting a weft thread through a shed using one or more jet nozzles for a flowing transport fluid characterized in that the jet noule is fed by a cyclically varying quantity of transport fluid.

3 Claims, 2 Drawing Figures METHOD FOR TRANSPORTING A WEFI THREAD THROUGH A SHED AND LOOM FOR PERFORMING SAID METHOD BACKGROUND OF THE INVENTION The invention relates to a method for inserting a weft thread into a shed making use of one or more jet nozzles for a flowing transport fluid. The invention also relates to a loom of the type in which the wefts are transported through the shed by means of one or more jet nozzles for a flowing transport fluid.

Recent experiments with looms of the above mentioned type have shown that a weft transported through the shed by a flowing fluid tends to lodge itself in the boundary layer surrounding the generally conical jet of the transport fluid.

It appeared furthermore that the energy transmission of a conical or differently shaped jet is greatest during the period immediately after the discharge of the jet begins in which said jet is still adjusting itself and therefore during a period in which the forming of the boundary layer is still in full swing. Where the nature of the jet cone varies less as a function of time, the energy transmission and therefore the force acting on the thread becomes smaller.

SUMMARY OF THE INVENTION Making use of this principle the invention proposes to feed the jet nozzle with a cyclically varying quantity of transport fluid. The object aimed at thereby is to retard the building of the boundary layer and to obtain an optimal energy transmission from the transport jets to the wefts during the whole operative period of the jet nozzle while a weft is being transported through the shed. Experiments have shown that in this manner the necessary quantity of transport fluid for transporting a weft in a predetermined time interval and through a predetermined distance through a shed, which fluid may be air, can be decreased by -30 percent. The amount of the savings in fluid of course depends on the function according to which the transport fluid supply to the jet noule varies.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a perspective view of a shed and one jet nozzle directed with its outflow opening into said shed, and also the means to have the jet nozzle issue a pulsating jet of transport fluid, and

FIG. 2 shows a diagram indicating the air consumption by applying such a pulsating jet according to the invention as well as by applying a constant jet.

In FIG. 1 the weft 2 presented at l is transported through the shed outlined by the upper warp sheet 3, the lower warp sheet 4 and the reed 5, by means of the jet cone 6 issued by the jet nozzle 7. The warp 2 is contained in a boundary layer around the conical core of the jet 6. The quantity of transport fluid, e.g., air issuing from the nozzle 7 per unit of time is not constant, however, but varies, e.g., according to the curve 8 in FIG. 2. The curve 8 shows how the rate of flow of the transport fluid through the jet nozzle varies as a function of time t, and indicates the quantity 0 of transport fluid which has to be supplied per unit of time to the jet nozzle 7 in order to transport one weft through the shed within a predetermined time interval. The same figure shows the quantity of transport fluid which is necessary when keeping the quantity of fluid issued per unit of time constant during the total operative period of the jet nozzle in order to transport one weft in the same time through the same distance through a shed. It appears thereby that the total air consumption is substantially smaller when the jet nozzle issues a cyclically varying quantity of transport fluid than if the supply of transport fluid remains constant.

FIG. 1 furthermore shows schematically that for realizing a pulsating transport fluid jet a slide type valve 9 may be used, the slide 10 of which is adapted to open and interupt in quick sequence the communication between the jet nozzle 7 and the source 11 of transport fluid by means of a schematically indicated actuating rod 12, which in its turn is controlled by a cam 13, the movement of which is derived from the main shaft of the weaving loom. Also for this purpose advantageously diaphragm valves may be used which comprise a valve closure element with negligable inertia which is of great advantage. Pulsatingvalves of the electro-magnetic type may also be employed.

I claim:

I. A method of transporting a weft thread through a shed by discharging a jet of fluid under pressure to entrain the weft thread, wherein the improvement comprises cyclically varying the amount of fluid discharged in the jet during the transport of a weft thread through the shed.

2. A method according to claim 1 wherein a pulsating jet of fluid is discharged during the transport of a weft thread through the shed, to entrain the thread.

3. A loom comprising a jet nozzle for discharging a jet of fluid to transport a weft thread through the shed, wherein the improvement comprises apparatus for cyclically varying the amount of fluid discharged in the jet during the transport of a weft thread through the shed.

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Claims (3)

1. A method of transporting a weft thread through a shed by discharging a jet of fluid under pressure to entrain the weft thread, wherein the improvement comprises cyclically varying the amount of fluid discharged in the jet during the transport of a weft thread through the shed.

2. A method according to claim 1 wherein a pulsating jet of fluid is discharged during the transport of a weft thread through the shed, to entrain the thread.

3. A loom comprising a jet nozzle for discharging a jet of fluid to transport a weft thread through the shed, wherein the improvement comprises apparatus for cyclically varying the amount of fluid discharged in the jet during the transport of a weft thread through the shed.

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