US3727646A

US3727646A - Apparatus for compensating the deviations of warp tension in weaving looms

Info

Publication number: US3727646A
Application number: US00136746A
Authority: US
Inventors: M Mares; S Nosek; L Martinek; V Rohlena
Original assignee: Vyzkumny Ustav Bavlnarsky AS
Current assignee: Vyzkumny Ustav Bavlnarsky AS
Priority date: 1970-04-28
Filing date: 1971-04-23
Publication date: 1973-04-17
Anticipated expiration: 1990-04-17
Also published as: ES390995A1; CA940419A; AT308663B; DE2120308A1; CS149784B1; CH526655A; FR2086424B1; FR2086424A1; GB1350653A; JPS5438229B1

Abstract

Apparatus for compensating the deviations of warp tension in weaving looms, especially weaving looms with simultaneous picking of weft threads into warp. Two parallel guiding support bars, spaced longitudinally of the warp, are arranged across the plane of the warp on one side thereof, said bars being provided with support edges. On the other side of the warp, opposite the portion of the warp limited by the support edges of the support bars, a warp deflecting member is arranged, said member working in counter phase with the device creating the shed.

Description

[75 Inventors: Milos United States Patent 1 Mares et al.

1 1 APPARATUS FOR COMPENSATING THE DEVIATIONS OF WARP TENSION IN WEAVING LOOMS Mares; Stanislav Nosek; Lumir Martinek; Vaclan Rohlena, all of Usti Nad Orlici, Czechoslovakia [73] Assignee: Vyskumny ustav bavlnarsky, Usti nad Orlici, Czechoslovakia 22 Filed: Apr. 23, 1971 21 Appl.No.: 136,746

[30] Foreign Application Priority Data Apr. 28, 1970 Czechoslovakia ..2944/70 521 US. Cl ..139/97, 139/12 [51] Int. CL. ..D03d 49/14, D03d 47/26 [58] Field of Search .,l39/24, 97, 98, 114,

[56] References Cited UNITED STATES PATENTS 2,649,864 8/1953 Mayer, Jr. et al. 139/97 3,483,897 12/1969 Pfarrwaller 139/98 1,817,203 8/1931 51 Apr. 17, 1973 1,749,123 3/ l 930 Benson 139/97 2,470,123 5/1949 Young ..139/97 X 2,556,055 6/1951 Bahan 1 ..139/97 3,125,128 3/1964 Pfarrwaller... ..139/115 3,342,218 9/1967 Rossmann ..139/12 FOREIGN PATENTS OR APPLICATIONS 473,667 10/ l 937 Great Britain ..139/97 6,332 0/1905 Great Britain... 1 39/24 134,413 9/1902 Germany ..139/24 174,693 9/1906 Germany ..139/24 1,237,034 6/1960 France ..139/12 Primary Examiner.1ames Kee Chi Att0rney--Arthur O. Klein [57] ABSTRACT Apparatus for compensating the deviations of warp tension in weaving looms, especially weaving looms with simultaneous picking of weft threads into warp. Two parallel guiding support bars, spaced longitudinally of the warp, are arranged across the plane of the warp on one side thereof, said bars being provided with support edges. On the other side of the warp, opposite the portion of the warp limited by the support edges of the support bars, a warp deflecting member is arranged, said member working in counter phase with the device creating the shed.

13 Claims, 17 Drawing Figures PATENTEDAPR 1 7197s SHEET 1 OF 3 SQCKQQ "w emons:

M1 LOS MARES, ST Amsmv NOS K, LuNuK MARTINEK A N E m R N A L C R v BY: M

ATTORNEY PATENTEUAPR1 71975 SHEET 3 BF 3 gs Y a m m Q mmv ATTORNEY APPARATUS FOR COMPENSATING THE DEVIATIONS OF WARP TENSION IN WEAVING LOOMS The present invention relates to an apparatus for compensating the deviations of warp tension in weaving looms, especially those with simultaneous picking of weft threads into warp; said changing tension is 'caused by creating the shed for inserting the weft, and

possibly also by further factors.

The tension of warp on a weaving loom is very unstable due to the formation of shed and further variations causing unfavorable strain of the warp yarn. This results, particularly in the case of yarn of rather poor quality, in very frequent break-ages. Because of this, weaving looms are equipped with devices reducing warp tension or attempting to balance its effects. The optimum condition is the maintenance of a constant level of basic tension of warp yarn throughout the whole weaving process, and that not only across the entire length of the weaving loom, but also across its entire width. The basic tension of warp is adjusted by a tension controller. The value of the basic tension depends upon the type of weave, of the warp setting, of the strength of warp yarn used, etc.

Various warp tension balancing devices are known.

The simplest of them appears to be a spring provided back rest. However, given its rather considerable mass, it cannot compensate quick changes of tension, particularly with high weaving speeds.

Another device serving this purpose, which is used in circular looms, comprises rotating arms with profiled rounded-up feet projecting into the warp. Such devices balance the tension only partially. Moreover, a danger of pushing down the warp yarn and of obtaining excessive warp wear through contacting the feet is inherent in this method. Some circular weaving looms use a swingable back rest divided into sections. In order to avoid considerable differences of balancing, resulting in double strips in the fabric, each section must be adjusted separately; such adjusting is very difficult because of inconvenient access. Differences of tension are noticeable for individual threads at the sides of the swingable back rest as opposed to the threads in the middle, the back rest being plane and the threads at the sides having a greater stroke than the stroke at the selvedge of the formed fabric. An equipment using a double shed for the purpose of balancing the tension is very complex. Moreover, the threading of warp threads in case of yarn breakage causes difficulties. Besides that, a considerable slip in the heddles is obtained.

The above drawbacks are substantially avoided by the apparatus of the invention for compensating the deviations of warp tension in weaving looms, especially those with simultaneous picking of weft threads. In accordance with the invention, from one side of warp in the section of plane of the warp between the back rail and the shed there are arranged two parallel guiding support bars leading across the plane of the warp and being provided with support edges. From the other side of the warp, opposite the section of the plane of warp limited by the support bars there is arranged a deflecting member of the warp working in counter phase with the device creating the shed. The distance between the support edges of the support bars is adjustable in a plane parallel with the plane of warp. At least one support bar is arranged swingably around its longitudinal axis and is provided with two support edges, while its position can be locked. The distance of the two support edges of the same support bar along its longitudinal axis are different. At least one support bar is mounted shiftably and swingably by means of its ends in a pair of opposite oblong openings formed in the sidewalls of the weaving loom and parallel with the plane of the warp, while said bar can be locked in its position. Along the, oblong openings scales are arranged. In the sidewalls bolts for locking the support bars in position are arranged. The distance between the deflecting member and the warp is adjustable. The deflecting member is arranged shiftably in the direction of the warp length in a plane which is parallel with the plane B.

The deflecting member of warp is formed as a rotating member in the shape of a cam the length of which corresponds at least to the width of the warp. The cam consists of a set of partial cams which are turned with respect to one another. The cam consists of a set of alternately arranged division laminae and deflecting laminae. The cam is formed like a helix with at least a single thread. Between the deflecting member and the warp a spacer is arranged in order to protect the warp from wear. The spacer is made of flat supple material, e.g. cloth, and consists of a cross rule accommodated shiftably in a guiding member in a direction which is perpendicular to the plane of the warp. Every partial cam is provided with a circumferential groove wherein there is slidably arranged a guide for the guide member in the shape of the character U, serving to accommodate the warp thread, the guide members being mounted on swingable holders. The guide members are fixedly connected with a resilient belt, while the one end thereof is attached to a frame at the side of the deflecting member opposite the direction of its rotation and the other end is attached to a tensioning spring anchored in the frame at the other side of the warp deflecting member.

An advantage of the apparatus according to the present invention consists in that the level of the basic warp yarn tension, i.e. the tension under a closed shed, as given by the controller, is maintained constant across the entire length and width of the warp throughout the whole time. At required moments, the tension can even be increased in order to achieve better technological effects, e.g. at the moment of beatingup, which results in better weaving characteristics. This is reserved solely for the beating-up. The breakage of warp yarn is kept down. Consequently, even secondrate warp yarn can be woven with good results. The fell of the fabric is straight, without undulations. The shed is clean, without sticking threads. The required compensation value can easily be adjusted even under working conditions.

The foregoing and other features of the apparatus according to the invention will be more fully explained in accompanying drawings in which:

FIG.1 is a time-tension graph of a warp thread on a weaving loom during the process of weaving, said loom being without any device for balancing the tension;

FIG.2 is a similar time-tension graph of a warp thread during the process of weaving with a loom having an apparatus for compensating the deviations of tension according to the present invention;

FIG.3 diagrammatically illustrates a weaving loom with an apparatus for compensation of the deviations of warp tension according to the invention;

FIG.4 is a front view of a cam-shaped warp deflecting member;

FlG.5 is a side view of the cam-shaped warp deflection member illustrated in F104;

FIG.6 diagrammatically illustrates an apparatus for compensating the deviations of warp tension with a deflecting member in the shape of a cam;

FIG.7 is a front view of a deflecting member of a further embodiment;

FlG.8 is a side view of the deflecting member of the further embodiment depicted in F 16.7;

FIG.9 is a front view of a warp deflecting member of helical shape;

FIG.10 is a side view of the warp deflecting member of helical shape depicted in FIG.9;

FIG. is a front view of a warp deflecting member consisting of partial cams;

FIG.12 is a side view of the warp deflecting member consisting of partial cams depicted in FIG. 1 1;

FIG.13 diagrammatically illustrates a further embodiment of apparatus for compensating deviations of warp tension;

FIG.14 shows a front view of a still further embodiment of an apparatus for compensating the dev-iations of warp tension;

FIG.15 is a cross-section of a partial cam of a warp deflection member;

F1616 is an axial section of the partial cam of a warp deflection member depicted in FIG.l;and

FIG.17 diagrammatically illustrates an alternative embodiment of an apparatus for compensating deviations of warp tension with a deflecting member provided with partial cams.

FIG.1 is a tension-time graph of one warp thread on a weaving loom without any device for balancing the warp tension. 0- Kmm is the basic tension of the warp thread when the shed is closed. The tension 0 m at'the lower shed and the tension 0- n at the upper shed is very unstable due to entering shocks exerting an unfavorable stress upon the yarn. 0' and a z are warp tension values at the moment of beating up.

As opposed to this state, the warp thread tension for a case wherein an apparatus for compensating the deviations of warp thread tension according to the present invention has been used is illustrated in F162 From this time-tension graph it is quite obvious that the tension 0 i.e. the basic tension of the warp given by the controller, is stabilized. The tensions o- 1 and a 2 in the moment of beating-up is stabilized to a practically identical value.

In the simplified diagram of a weaving loom shown in FIG.3, there is shown a warp beam 1 upon which the thread of the warp 2 is wound. From the warp beam 1 the system of warp threads, i.e. the warp 2 is fed over a back rail 3, then over the apparatus for compensating the deviations of the tension of warp 2. The warp tension compensating apparatus, shown contained in a frame, comprises substantially two support bars 6 and warp deflectors 5. The support bars 6 are disposed above the warp 2 with their lower edges 4 in the plane B of warp 2, the edges 4 being spaced by a distance A. The support bars 6 are parallel and extend across the plane B of warp 2. Under warp 2 a deflecting member 5 is rotatably accommodated on a shaft 17, said deflecting member having the shape ofa cam with a functional profile, further referred to as deflecting profile 49, marked with cross hatching. The deflecting member 5 is arranged opposite the sector of the plane B limited by two support edges 4 of support bars 6 and is designed to deflect the warp 2 from its plane B against the action of the support bars 6 through a distance h This deflection of warp 2 is shown in dash lines. Also, the circular path of the apex of the deflecting profile 49 extending across the plane B is shown in dash lines. The difference between the radius of the highest apex of the deflecting profile 49 and the radius of the functionless, curcular cylindrical part of the cam containing the warp 2 in its plane B equals, in the described embodiment, the height k of the deflection of the warp 2.

The warp 2 further passes over the lease 7, over the front rod 8, over the harness of heddle shafts or rods 9 creating the shed 15, further over a reed 10 behind which the fell 11 of the fabric already passes over a tentering member 12 to the rough beam 13 and to the cloth beam 14. The drive of the weaving loom has not i been illustrated. The drive of the deflecting member 5 has not been illustrated either, since this latter drive must be coupled with the drive creating the shed 15 in such a way that the deflecting member 5 and the device for creating the shed 15 cooperate in mutual counter phase, i.e. when the warp 2 is being deflected from plane B, the shed l5 closes and vice-versa. For simplicity of illustration, the controller of the basic warp 2 tension has not been illustrated. The dimension of the shed 15 are given by its length m, height h,, measured from the weaving plane C, and further by the front distance r of the shed 15 from the middle of heddle shafts 9 to the fell 11 of the fabric. The plane B of the warp 2 and the weaving plane C, in this case, coincide. The distance between the axis of the warp beam 1 and the fell 11 of the fabric is designated l The length l of the pre-cloth 16 is the distance between the fell 11 of the fabric and the axis of the rough beam 13.

The deflecting member 5, formed as a rotat-ing element in the shape of a cam, is illustrated in FIGSA and 5. The deflecting profile 49 extends parallel to the axis of member 5 and is the same across the entire working length of said cam corresponding with the width of warp 2. The deflecting member 5 may be employed in unconventional and Jacquard machines.

In the embodimentof FlG.6, the cam 18 is mounted on shaft 17 allowing both its rotational seating and drive. The cam 18 can carry even more deflecting profiles 49 across its whole length. In the diagrammatic representation of FIG.6, two support bars 6 with support edges 4 are arranged from one side of the warp 2. The support edges 4 contact the warp 2 with a spacing A. From the other side of warp 2 a deflecting member 5 formed in the shape of said cam 18 is rotatably accommodated on the shaft 17. The deflecting member 5 is disposed opposite the sector of the plane B defined by two support edges 4 of the support bars 6.'Between the cam 18 and the warp 2 a spacer 19 of flat supple material, e.g. a cloth, a foil of plastic material, is arranged across the entire width of the warp 2. The spacer 19 is fixed by means of a bolt 20 and a washer 21 on an angle 22 mounted on a frame (not shown) of the weaving loom. The angle 22 is arranged at the side of the cam 18, in the opposite direction to the direction of its rotation marked with an arrow. The spacer 19 serves to prevent the warp 2 from wear caused by the rotating cam 18, the relative movement between the spacer 19 and the warp 2 being so negligible that it need not be taken into account.

The warp deflecting element 5 illustrated in FIGS.7 and 8 consists of a system of alternatively arranged dividing laminae 23 and deflecting laminae 24. The whole system is accommodated on shaft 17. Element 5 is used for special forms of shed l5, and consequently also for various weaves. Single threads or groups of threads of warp 2 are fed over deflecting laminae 24. The dividing laminae 24 prevent the threads of warp 2 from being pushed aside.

In FIGS.9 and the deflecting member 10 has the shape of a single helix 25 accommodated on shaft 17. It is designed for compensating the deviations of the tension of warp 2 in weaving looms with a continuous travelling-wave shed. The pitch of the helix corresponds with the length of the travelling wave. The deflecting profile 49 can have the form of a multiple thread according to the requirements.

In FIGSJI and 12 the deflecting member is com posed of partial earns 25 of the same shape, turned with respect to one another by a certain angle a. The partial cams 26 are accommodated on shaft 17. The system of partial cams 26 is designed for weaving looms with a sectional wave shed. I

The apparatus for compensating the deviations of warp tension according to the diagrammatic illustration in FIG.13 applies two support bars 6 with support edges contacting the warp 2 from above. Between the support edges 4 are spaced a distance A. Under the warp 2 cpposite the sector B of the plane limited by the support edges 4 a cross rule 27 is arranged in guide rails 28, the rule 27 being perpendicularly slidable with respect to the plane B. The rule 27 is connected with the draw bar 29 meshing with a balancing cam 30 which is rotatably accommodated on shaft 17. The rule 27 performs a linear movement in the direction of the arrow, and its stroke equals the height h above the plane B of warp 2. Both support bars 6 are accommodated swingably around their longitudinal axes, each of them being provided with two support edges 4, 4a. The cross rule 27 is seated against the warp 2 in the crosswise direction. Its linear movement eliminates wear of warp 2.

The embodiment illustrated in FIGS.14, 15, and '16 is arranged in a frame 31 with two side walls 32. For better illustration only one of the side walls 32 has been depicted in FIG.14. In the upper side' of the side walls 32 over the plane B of the warp 2 two pairs of opposite oblong openings 33 are formed which are parallel with plane B of warp 2. The scales 34 are arranged along the openings 33. In the oblong openings 33, the support bars 6 are shiftably and swingably accommodated with their ends in the oblong openings 33. For a better illustration of the possible adjustment range of the spacing A and A of their support edges 4, 4a, two support bars 6 are arranged in each opposite pair of oblong openings 33. The support edges 4 of two support bars 6 bear against the warp 2. The support edges 4 and 4a of the support bar 6 have different distances from its length axis. The bolts 35 serve to fix the position of the support bars 6. On the sidewall 32 the base 36 is mounted, a deflecting member on base 36 being arranged under the warp 2. Said deflecting member includes a set of partial cams 26 turned with respect to one another shiftably in the vertical direction perpendicular to the plane B of warp 2 in the sector of plane B limited by the support edges 4 of the support bars 6. A bolt 37 passing through a projection 38 fixed at the sidewall 32 serves for the shifting.

The partial earns 26 are mounted on shaft 17 connected with a drive (not shown). Said drive is coupled with the device insuring the creation of the shed 15 working in counter phase with it, i.e. when the deflecting of warp 2 from the plane B sets in, the shed 15 closes and vice-versa. In every partial cam 26 a circumferential groove 39 is provided wherein a guide 40 is slidably accommodated, on said guide there being fixed a guide member 41 in the shape of the letter U. The guide members 41 on all partial cams are fixedly connected with a resilient belt 42. The one end of the resilient belt 43 is fixed by means of a bolt 4'] on an L- shaped bar 44 at the side of the deflecting member 5 opposite the direction of its rotation marked with an arrow, whereas the other end is fixed to the tensioning spring 43 anchored at an L-shaped bar 45 at the other side of the deflecting member 5. Both L-shaped bars 44 and 45 are fixed in the frame of the weaving loom. The yarn of the warp 2 has been divided into sections, and the individual sections have been arranged in the guiding members 41 of the respective partial cams 26. The apparatus is designed for weaving looms with a sectional wave shed 15.

In an unillustrated alternative embodiment the warp deflecting member is connected with the L-shaped bars 44, 45 which are slidably arranged in frame 31 so as to be shiftable in a direction parallel with plane B, i.e. in the direction of the length of warp 2; see the arrow in FIG.14. This shifting is obtained by means of the screw 50.

In an embodiment similar to the preceding (FIG.17), the guide members 41 are fixedly connected with a lever 46 swingable around a pin 48 on the L-shaped bar 44.

The most suitable place for accommodating an apparatus according to the invention is the sector of the plane B of warp 2 between the back rail 3 and the shed 15. In this area sufficient space is provided for changing the spacing A between the edges 4 of the support bars 6 The warp deflecting member can be formed either as a reciprocating element performing a linear movement perpendicular to the plane B of the warp 2, or as a rotating member. Most frequently the cam 18 serves as a rotating member, said cam being provided with a deflecting profile 49 of continuous course which is the same along the entire length of said cam corresponding at least to the width of the warp 2. There can be more than one deflecting profile 49 on cam 18, said profiles being turned with respect to one another, i.e. the cam 18 can be double-acting or multiple-acting As has been described in connection with the FIGS.9 and 10, a deflecting member in the shape of a helix 23 can be obtained by twisting the deflecting profile 49 to a singlethread or a multi-thread helix.

The warp deflecting member according to FIGS. 11 and 12 will be obtained by composing partial cams of identical shape, turned by a certain angle a with respect to one another.

The size and the geometry of the deflecting member, particularly that of its deflecting profile 49, depend upon the type and the process of formation of shed 15, i.e. from the required type of weave of the fabric.

For the compensation of the deviations of the tension of warp 2, the following condition is valid:

Provided the tension const. that can be determined by the basic tension controller only, and provided we consider Hooks law to be valid, and consequently, E const., then p const. at any moment:

P Pa ir/u Po Mm Mm const- Wherefrom the condition must be fulfilled:

Mm! p/r/ Mm const' Where: F=force S yarn section 6 relative extension E modulus of elasticity Ap elongation depending from a K and from the length p p length of stressed warp p length of free warp k const. elongation of the length of warp h elongation caused by the shed and by other factors A elongation caused by the warp tension compensating apparatus h elongation caused by the time change of the shed, the play in the heddles, the play of heddles in the holders of the shafts, further by the geometric form of the shed m and r (FIG.3), the maximum stroke of the shed h max., the movement of the shafts, linear or along a radius, by the number of the heddle shafts or rods, the beat-up, and further also with respect to the shape of the spacers 12, the arrangement of the fell 11 of the fabric, the length of the pre-cloth p etc. I The majority of time-dependent influences are among those which we wish to suppress or to balance in an exact way, since they have an unfavorable effect upon the stressing of the yarn. However, the beating-up represents an effect that must be maintained, and even strengthened, in order to obtain good weaving characteristics. The negative sign A will have an intensifying effect in the elongation, the other influences and their elongation (A will have the same sign. Then:

Mm Mum mm Mum] and the resulting formula for compensating the elongation A will read as follows:

For a constant elongation A the maximum value of all factors affecting the weaving process is taken into consideration, i.e. A max. The deflecting member must have a shape fulfilling this condition:

5 for the minimal spacing A min of the support edges 4 or 4a of the support bars 6 (FIG. 3). The plane B is identical with the plane of warp 2 where the deflecting member 5 of warp 2 does not have effect. The deflecting member 5 of warp 2 disturbs the plane B, thus bringing about the elongation A A correct set-up of the apparatus for compensating the deviations of warp tension in accordance with the actual conditions of various influences upon the weaving process is obtained either by changing the spacing A between the support edges 4 of the support bars 6 or by changing the height h (FlG.3), or possibly by a combination of both these changes. Another possibility of adjustment is given by the shift-ability of the deflecting member 5 in a plane parallel with the plane B in the longitudinal direction of warp 2, as marked by the arrow in FIG.14. By means of this shifting, under given height h,; and given spacing A, the form of deflection of warp 2, and consequently also its elongation are changed. The shifting can be carried out by means of bolt 50.

The change of height h,, in an apparatus with a warp deflecting member in the form of a rotating member can be carried out either by simply exchanging the 0 rotating element for another rotating element of required dimensions, or by changing the distance of the deflecting member 5 from the warp 2. In this latter case the deflecting member 5 is arranged shiftably in the frame 31 of the weaving loom (FIG.14) and the shifting of said deflecting member 5 in the direction which is perpendicular to the plane B of warp 2 is performed by means of the bolt 37. The adjusting range of the height h is given by the difference between the radius of the circle circumscribed by the apex of the deflecting profile 49 and the radius of the functionless part of the rotating element (FlGS.3 and 6). The maximum height 11,; can be obtained, in this case, by shifting the rotating element in the direction towards the warp 2, until its functionless part contacts the warp 2. By its further shifting the functionless part intersects the plane B and the warp 2 is partially deflected from the plane B. This possibility can also be made use of in some particular cases.

In an embodiment with a deflecting member 5 which performs the deflecting along a straight line perpendicularly to the plane B of the warp 2, the change of h is obtained by shifting the entire deflecting member perpendicularly to the plane B of warp 2 or by changing the stroke of said member.

The change of the spacing A between the support edges 4 is performed by shifting one or both support bars 6 in a plane parallel with plane B in the longitudinal direction of warp 2 so as to insure their parallelism after adjusting and fixing them. The value of the shift of the support bars 6 can be easily determined by means of scales 34 (FlG.l4). Quick changes of the spacing A can be obtained by turning one or both bars 6 provided with two support edges 4 and 4a (FIGS.13 and 14) and by pressing the selected edges 4 or 4a against the warp 2. At the same time also, the bars 6 can be shifted, particularly if fine adjustment of the spacing A is required.

Under conditions of various geometric shape of the shed l and various modes of technological adjustment of the loom it is possible by simply setting the spacing A by means of bars 6 according to the scale 30 either to increase or to decrease the effect of compensation to the required degree, or to perform an exact balancement that the following condition of compensation be valid:

Mm! ra/(1 Mm constbasic tension of warp 2.

When the weaving loom has been adjusted, the required height h and the spacing A have been set, a drive mechanism. (not shown) is switched on.'For a concise description of the function of an embodiment of the invention the starting position of theweaving loom is supposed to correspond with the one depicted in FIG.3, i.e. with the shed 15 fully open, under which conditions the function will be described. The cam of the deflecting member 5 starts rotating in the sense of the arrow. As long as the functionless part of the cam contacts warp 2,the shed 15 remains open for picking the weft and the warp 2 remains in the plane B. As soon as the deflecting profile 49 of the cam starts intersecting the plane B, the warp 2, bearing against both support edges 4 or the support bars 6 starts deflecting itself, which is accompanied by the closing movement of the shed 15. When the maximum deflection of warp 2 has been reached, i.e. at the maximum value of height h,; the shed is closed, i.e. the height h, equals zero. During the further rotation of the cam, the height h decreases again and a new shed 15 starts forming-itself the height h of which reaches its maximum when the deflecting profile 49 of the cam stops intersecting the plane B and the warp 2 merge. This process is'repeated all the time. The deflecting member 5, consequently,

works in counterphase with the equipment forming the shed 15. In other words, to the same degree to which the warp 2 tension caused by the deflecting member 5 increases, the tension of warp 2 is slacked down by closing the shed 15, and vice-versa. The height h as well as the shape of the warp 2 deflected out of the plane B by the deflecting member 5, but also the spacing A between the support edges 4 of the support bars 6 is exactly defined. The deflecting of warp 2 by the deflecting member 5 is performed only in the sector of the plane B of warp 2 limited by the support edges 4 of the support bars 6 and against the direction of their influence, i.e. the support bars 6 operate always from the one side of warp 2, whereas the deflecting member 5 operates from its other side. The level of the basic tension a given by the controller of the tension of warp 2 is, consequently, constant within the entire weaving process during the time t outside the area of the beatup (FIG.2).

Devices for compensating the warp 2 tension using deflecting members 5 as embodied in FIGS], 8, 9, 10,

ll, 12, and 14 operate in the same way, with the only difference being that they do not deflect all threads of warp 2 across its entire width at the same time, but according to a selected program, in most cases progressing consecutively by one or a plurality of sections.

The operation of the deflecting member 5 moving along a straight line perpendicular to the plane B of warp 2 is obvious from F1613, lbeing analogous with the operation of devices described hereinbefore.

The rotating cam is in continuous contact with warp 2. In order to prevent the threads of warp 2 from wear, a spacer 19 of flat supple material is inserted between the cam and the warp 2, e. g. of cloth, of plastic material etc. (F1613). The same function is performed by the guide 40 of the guidng member 41 (FlGS.14, 15, 16, 17).

in some particular cases, the height h can be adapted by swinging out the edges 4, 4a on one or both bars 6 so as to let them intersect the plane B of warp 2, which can increase the effectivity of the deflecting member 5.

Although the invention is illustrated and described with reference to a plurality of preferred embodiments, it is to be expressly understood that it is in no way limited to the disclosure of such a plurality of embodiments, but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

L'In a weaving loom with simultaneous picking of theweft threads into progressive warp-shed and having a progressive shedproducing device, an apparatus for compensating the deviations of warp tension during the shed creation comprising two parallel support bars arranged leading across the plane of the warp on one side thereof, a rotating deflecting warp member on the other side of the warp opposite the section of the warp limited 'by the support bars, said rotating deflecting warp member being formed like helical cam means with at least a single helix and means for driving the ,member in a counterphase with the device creatingthe shed.

2. Apparatus as defined in claim 1, wherein the support bars being provided with support edges and comprising means for adjusting the distance between the support edges in a plane parallel with the plane of warp.

3. Apparatus as defined in claim 1, wherein at least one support bar is arranged swingably around its longitudinal axis and is provided with two support edges, and comprising means for selectively locking said one support bar in position.

4. Apparatus as claimed in claim 3, wherein the distance of both support edges of the same support bar along its longitudinal axis is different.

5. Apparatus as claimed in claim 1, wherein at least one support bar is mounted shiftably and swingably by means of its ends in a pair of opposite oblong openings formed in the sidewalls of the weaving loom and parallel with the plane of the warp, and comprising means for selectively locking said bar in its position.

6. Apparatus according to claim 1, wherein the rotating warp deflecting member can be adjusted relative to the warp.

7. Apparatus according to claim 1, wherein the rotating warp deflecting member is mounted for shifting in the direction of the warp length in a plane which is generally parallel thereto.

8. Apparatus according to claim 1, wherein the helical cam comprises a set of partial cams which are turned with respect to one another.

9. Appparatus according to claim 8, wherein the partial cams are formed of a set of alternately arranged division laminal and deflecting laminae.

10. Apparatus according to claim 1, wherein between the rotating warp deflecting member and the warp there is disposed a spacer in order to prevent the warp from wear.

11. Apparatus according to claim 10, wherein the spacer is made of flat supple material.

12. Apparatus according to claim 8, wherein every partial cam is provided with a circumferential groove wherein there is slidably arranged a guide for a U- shaped guide member which accommodates the warp thread, the guide members being mounted on swingable holders.

13. Apparatus according to claim 12, wherein the guide members are fixedly connected with a resilient belt, one end of the belt being attached to a frame at the side of the rotating warp deflecting member opposite the direction of its rotation, the other end of the belt being attached to a tensioning spring anchored in the frame at the other side of the rotating warp deflecting member.

Claims

1. In a weaving loom with simultaneous picking of the weft threads into progressive warp-shed and having a progressive shedproducing device, an apparatus for compensating the deviations of warp tension during the shed creation comprising two parallel support bars arranged leading across the plane of the warp on one side thereof, a rotating deflecting warp member on the other side of the warp opposite the section of the warp limited by the support bars, said rotating deflecting warp member being formed like helical cam means with at least a single helix and means for driving the member in a counterphase with the device creating the shed.

12. Apparatus according to claim 8, wherein every partial cam is provided with a circumferential groove wherein there is slidably arranged a guide for a U-shaped guide member which accommodates the warp thread, the guide members being mounted on swingable holders.