US3465791A - Apparatus for assisting the jet insertion of a weft thread into the shed of a loom - Google Patents

Description

Sept. 9, 1969 H. P. VAN MULLEKOM ,7

APPARATUS FOR ASSISTING THE JET INSERTION OF A WEFT THREAD INTO THE SHED OF A LOOM 3 Sheets-Sheet 1 Filed July 18, 1967 p 9, 1969 H. P. VAN MULLEKOM 3 APPARATUS FOR ASSISTING THE JET INSERTION OF A WEFT THREAD INTO THE SHED OF A LOOM Filed July 18, 1967 5 Sheets-Sheet 2 Sept. 9, 1969 VAN MU EKOM 3,465,791

H. APPARATUS FOR 515'! T INSERTION OF A WEFT THREAD INTO T 'SHED A LOOM Filed July 18, 1967 3 Sheets-Sheet 3 Patented Sept. 9, 1969 3,465,791 APPARATUS FOR ASSISTING THE JET INSERTION OF A WEFT THREAD INTO THE SHED OF A LOOM Hubert Peter van Mullekom, Deurne, Netherlands, as-

signor to N.V. Machinenfabriek L. te Strake, Deurne, Netherlands, a Dutch company Filed July 18, 1967, Ser. No. 654,222 Int. Cl. D03d 47/34, 47/00 US. Cl. 139-127 1 Claim ABSTRACT OF THE DISCLOSURE This apparatus is used in a loom having Warp sheets which are maintained momentarily in diverging warp planes, and having a reed which is movable between a beating position and a retracted position. In such a loom, the warp sheets when maintained in said diverging warp planes, together with the reed when in its retracted position, form a shed which is substantially triangular in cross-section. The apparatus is used for controlling and assisting the movement of a weft thread which is jetinserted into the shed in a path that is substantially equally distant from the warp planes and from the retracted reed. The apparatus comprises a plurality of jet nozzles, each of which is arranged to extend into the shed adjacent to a corner of the triangular cross-section, and each of which has an orifice for discharging a jet of fluid. Each orifice is directed to discharge fluid substantially longitudinally of the shed, and the distance of the orifice from the center of a circle inscribed in the triangular cross-section of the shed is substantially as great as the radius of the circle.

BACKGROUND OF THE INVENTION The invention relates to a device for assisting the jet insertion of a weft thread into the shed of a loom, comprising a number of jet nozzles in front of the reed, which jet nozzles create a jet of a fluid under pressure within the shed when the reed remains in its distant position, for assisting in inserting a weft into the shed.

In looms in which a weft is to be inserted into the shed by jet action of a fluid under pressure such as air it is generally known to arrange a number of jet nozzles with in the shed formed by the upper and lower warp sheet in front of the reed. By this arrangement relatively wide fabrics can be woven, which fabrics thus have long wefts. In such known looms of this kind jet nozzles have been situated near the upper and lower warp sheets in such a manner, that groups of warp threads are pressed somewhat into the shed, owing to which the air, streaming out of the jet nozzles can enter into the shed.

In another type of such known looms use, shown in US. Patent No. 3,139,118, is made of members which penetrate into the shed between the warp threads some of which members are provided with annular jet nozzles, and others of which members are of such an annular shape that a channel is formed by these members within the shed, through which channel a Weft can be conveyed. The annular blowing nozzles of some of the members and the annular portions of the other members are not entirely closed and a Weft which remains within the channel formed by the annular portions and annular jet nozzles can be laterally removed from the channel in order to be able to beat the weft against the fabric when the reed performs its beating stroke after the members have been removed out of the shed. Thus the jet nozzles which are situated in an annular mounting are directed towards the centre line of the channel.

It is also known to situate the jet nozzles in such a manner that the jets leaving the nozzles are situated in the path of the weft to be inserted. The jet nozzles can move between the warp threads into and out of the shed. A weft to be inserted into the shed prefers to seek the jets leaving the jet nozzles owing to which the position of the weft to be inserted is in some measure localized.

It has been observed that when the production speed of a loom is to be increased the required fast air streams, which occur within the shed during the weft insertion, cause side effects, which are detrimental for the weft insertion. Such side effects are also the consequence of the triangular cross section of the shed. The side effects consist substantially in secondary air streams which cause a deviation of the path of the weft. For this reason it has been proposed to modify the shape of the shed under these circumstances by an especial shape of the blades of the reed, which blades therefore have an arcuated shape. However, the result of this arrangement did not meet the expectations.

When increasing the production speed of a loom the conveying speed of the weft through the shed must be considerably increased and it can happen that at a given moment the weft comes suddenly out of its path and will contact the warp threads with the result that the weft becomes entangled within the shed.

The difficulties indicated above are the result of air cushions and different air speeds of the whole air column which moves within the shed.

SUMMARY OF THE INVENTION It has been pointed out that these difficulties can be eliminated by a manner of handling the weft to be inserted by the jets, which differs from the manner which was used in conveying the weft in the known constructions.

The object of the invention is to eliminate the above mentioned drawbacks, and a loom according to the invention is characterized in that the jet nozzles are situated near one or more corners of the shed, which jet nozzles are eccentrically situated with respect to an inscribed circle within a triangle, which is formed by the warp sheets and the reed. Thus the triangle defined by the warp sheets and the reed is perpendicular to the conveying direction of the weft, which Weft preferably is conveyed through the centre of the inscribed circle, because in this position the distance from the weft to be launched to the warp sheets as well as the distance from the weft to the reed is as large as possible.

Another characterizing feature of the loom according to the invention is that the jet nozzles are situated on the bisectrices of the angles in the corners of the shed and on or outside the inscribed circle in the triangle defined by the upper and lower warp sheets and the reed in a retracted position.

In a preferred embodiment of a loom according to the invention the jet nozzles are provided in a blade shaped mounting which mounting is provided with a single laterally directed exhaust opening, situated in or near the plane which bisects the angle formed by the upper and lower warp sheets. In this arrangement jet nozzles may be also provided in the corners of the shed near the reed and the jet nozzles in the corners near the reed may be arranged, in the direction of the weft, between adjacent pairs of the jet nozzles in the corner of the shed formed by the upper and lower warp sheets. The lateral openings of the jet nozzles are directed in such a manner that the jet streams leaving these openings will have a slight lateral component which is situated in a plane formed by the bisectrices of the angles in the concerning corners.

3 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross section through the reed of a loom according to the invention;

FIG. 2 shows a sectional view taken on the line IIII in FIG. 1;

FIG. 3 is a cross section similar to that shown in FIG. 1 but in diagrammatic form, showing the arrangement of jet nozzles in each corner of the shed and FIG. 4 is a sectional view taken on the line IVIV in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment shown in FIG. 1, warp sheets 1a and 1b are maintained momentarily in diverging warp planes in the positions shown. In accordance with conventional loom operation, the positions of the warp sheets are reversed periodically, but between reversals one of the warp sheets is maintained momentarily in the upper warp plane, and the other warp sheet is maintained momentarily in the lower warp plane. Hereinafter, in describing a particular stage in the operation of the loom, that particular warp sheet which is momentarily maintained in the upper warp plane is called the upper Warp sheet 1a, and that particular warp sheet which happens to be momentarily maintained in the lower warp plane is called the lower warp sheet 1b. At the time when the warp sheets are being maintained momentarily in the diverglng Warp planes, the shed is formed by an upper warp sheet 1a and a lower warp sheet 1b. The warp sheet threads 1a and the warp sheet 1b come together at the end of the shed and merge into the fabric 2. The warp sheets 1a and 1b thus form a sharp angle at the end of the shed near the fabric 2. Opposite to the fabric the shed is limited by the blades 3 of the reed. The reed blades 3 are fastened in a lay beam 4 and a reed cap 5 in a manner as is usual in reed constructions.

As usual in looms in which a weft is to be inserted into the shed by jet action of a fluid a baflle plate 6 is situated immediately below the lower warp sheet 1b and a bafile plate 7 is arranged immediately above the upper warp sheet In. The spaces between the warps threads are thus covered by the baflie plates in order to obtain a good flow of the conveying medium for the weft within the shed.

The baffle plate 6 is fastened to the lay beam 4 and the bafile plate 7 is fastened to the reed cap 5, the reed being movable between the retracted position in which it is shown in FIG. 1 and the beating position indicated in phantom lines in FIG. 1. A weft thread is jet-inserted into the shed, from an open end of the shed at one side of the warp, while the parts are in the positions shown in FIG. 1. A weft thread which is to be inserted into the shed will be preferably launched in the central part of the shed where the distance between the weft and the Warp sheets and further between the weft and the blades 3 of the reed is as large as possible, so that the weft thread is jet-inserted into the shed in a path that is substantially equidistant from the warp sheets and from the retracted reed, and is thus near the centre of an inscribed circle in the triangle formed by the upper warp sheet 1a, the lower warp sheet 1b and the blades of the reed. The concerning inscribed circle is indicated by the reference numeral 8 in FIG. 1.

According to the invention the jet nozzles are not situated near the centre of the inscribed circle 8 but extend into the shed near a corner of the triangular cross-section of the shed. In the embodiment according to FIGS. 1 and 2 the jet nozzles are situated near that corner, which is formed by the upper warp sheet 1a and the lower warp sheet 1b near the fabric 2. The jet nozzles are in the form of blades 9, situated on the baffle 6. The blades are shaped in such a manner that they have a sharp edge which can easily penetrate between the threads of the lower warp sheet 1b into the shed. A simple discharge orifice is arranged in the lateral side wall of the blades 9a (FIG. 2). The orifice 10 is adapted to discharge a jet of the fluid under pressure, preferably air under pressure, which streams out of this orifice. The blades 9a and 9a are applied to assist and control the movement of a weft thread which is being jet-inserted from the right side or from the left side of the shed. A number of jet nozzles or blades 9a are regularly interspaced at intervals longitudinally of the shed.

When a weft has been launched from the right side of the shed a fluid such as air under pressure is led to the channel 11 and further through this channel to the orifice 10 of the jet nozzles or blades 9a.

When now a weft has been launched from the left side of the shed the admittance of fluid through the channel 11 is interrupted and the fluid, such as air under pressure, is admitted to the channel 12 and further to the jet nozzles or blades 9a. The admittance of the fluid to the channels 11 and 12 can be regulated by means of control valves known per se, which valves are actuated by a movable part, which is synchronously driven by the main shaft of the loorn.

Instead of two blades 9a and 9a adapted as jet nozzles one single blade adapted as a jet nozzle can be provided; however, this blade is provided with two orifices. These jet nozzles, consisting of a single blade having two orifices, are indicated by the reference numeral 912 in FIG. 2 and the orifices in the side walls of the blades are indicated by the reference numerals 10 and 10". The orifice 10 is connected to the channel 11 and the orifice 10" is connected to the channel 12. The jets of the fluid, which streams out of the orifices are indicated by lines 13 in FIG. 2. From the direction of the lines 13 it appears that the jets, leaving the orifices, although directed substantially longitudinally of the shed, are not entirely parallel to the path of the inserted weft but have a laterally directed component. The deviation of the jets by their laterally directed component, however, is exaggerated in FIG. 2.

It is not necessary that the jet nozzles be only situated in one corner of the shed between the upper warp sheet 1a and the lower warp sheet 1b. Jet nozzles can also be situated in the other corners of the shed as indicated in FIG. 3. In this case jet nozzles 14 and 15 are provided insides the jet nozzles 9. The jet nozzles 14 are situated in that corner of the shed which is formed by the plane at the upper warp sheet In and the blades 3 of the reed. The jet nozzles 15 are situated in that corner of the shed which is formed by the plane at the lower warp sheet 1b and the blades 3 of the reed. The jet nozzles 9, 14 and 15 can be alternately arranged as indicated in FIG. 4. In such a case two other jet nozzles in the upper and lower corners of the shed are always situated between two adjacent jet nozzles 9. The two jet nozzles 14 and 15 in the lower portion of FIG. 4 are thus situated between two nozzles 9. The jet nozzles are thus arranged around an inscribed circle within a triangle which is formed by the upper and lower warp sheets and by the reed. The provision of the jet nozzles in all corners of the shed is advantageous and the jet nozzles each consist of a blade like the blade 9 which penetrates the shed in the same manner as the blade 9, as indicated in FIG. 4. Each of the blades has an orifice that lies substantially in a plane bisecting the angle at the corner of the triangular crosssection of the shed, and is directed to discharge fluid in a direction substantially parallel to such plane but at a slight angle to the path of the inserted weft thread, as indicated in FIG. 4. Each of the orifices lies substantially on or outside of a circle inscribed in the triangular crosssection of the shed, so that the distance of each orifice from the center of such circle is substantially as great as the radius of the circle. In the practice of the present invention, the number of the jet nozzles required for a given width of the loom increases as the velocity at which the warp thread is inserted increases. FIG. 2 illustrates an arrangement in which a single jet nozzle 9b or a pair of jet nozzles 9a and 9a are provided in only one corner of the shed opposite every fifteenth blade of the reed. FIG. 4 illustrates an arrangement which permits the warp thread to be inserted at a still higher velocity, in which the jet nozzles are located in all three corners of the shed, opposite every fifth blade of the reed.

In this manner hindering side effects as a result of secondary air streams caused by the movement of the reed and by changing of the shed, which sometimes will have the character of a pressure wave, can be avoided and the jets leaving the jet nozzles cannot be disturbed by the side effects, resulting in a good weft insertion into the shed.

Having now particularly described and ascertained the nature of my invention I declare, that what I claim is:

1. In a loom having warp sheets which are maintained momentarily in diverging warp planes, and having a reed which is movable between a beating position and a retracted position, the warp sheets when maintained in said diverging warp planes, together with the reed when in its retracted position, forming a shed which is substantially triangular in cross-section, an improved apparatus for controlling and assisting the movement of a weft thread which is jet-inserted into said shed in a path that is substantially equidistant from the warp planes and from the retracted reed, said apparatus comprising a plurality of jet nozzles located at intervals longitudinally of said shed, each of which is arranged to extend into said shed adjacent to the corner of the triangular cross-section where the warp planes meet, said jet nozzles alternating with further jet nozzles that are arranged to extend into the shed adjacent to the other two corners of the triangular cross-section, and each of the jet nozzles having an orifice for discharging a jet of fluid, such orifice being directed to discharge fluid substantially longitudinally of said shed, and the distance of such orifice from the center of a circle inscribed in the triangular cross-section of said shed being substantially as great as the radius of such circle.

References Cited UNITED STATES PATENTS 3,139,118 6/1964 Svaty.

3,161,209 12/1964 Scheifel 139-427 3,162,215 12/1964 Saito 1391'27 FOREIGN PATENTS 1,449,084 7/ 1966 France.

OTHER REFERENCES German printed application 1,076,586, Feb. 2, 1960, to Priller.

HENRY S. IAUDON, Primary Examiner

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