US2089620A - Apparatus for controlling thread tension in looms for weaving - Google Patents

Description

R. ROSSMANN APPARATUS FOR CONTROLLING THREAD TENSION IN LoOMs FOR WEAVING Filed Jan. 10, 1935 3 Sheets-Sheet l FoJJnzazzzz. M 4

A, 10, 1937., R. ROSSMANNY APPARATUS FOR CONTROLLING THREAD TENSION IN LOOMS FOR WEAVING Filed Jan. 1Q, 1935 3-Sheets-Sheet 2 JIM? Jeiibruqy.

Au 10, 1937.. R. ROSSM'ANN APPARATUS FOR CONTROLLING THREAD TENSION IN LOOMS FOR WEAVING Filed Jan. 10, 1955 3 Sheets-Sheet 5 72221222 for jniozfiflmzan 2;

Patented Aug. 10, 1937 PATENT OFFICE APPARATUS FOR CONTROLLING THREAD TENSION IN LOOMS FOR WEAVING Rudolf Winterthur, Switzerland, as-

signor to Tefag Textil-Finanz A. G., Zurich,

Switzerland Application January 10, 1935, Serial No. 1,166

In Switzerland 8 Claims.

Thisinvention relates to a method and apparatus for controlling the tension of the weft thread in looms, particularly in looms having gripper shuttles.

In looms operating with gripper shuttles, the conditions of and around the weft thread are different from the conditions in looms operating with shuttles carrying thesupply of thread themselves. In the latter case, the weft thread which 10 has left the shuttle rests stationary within the shed, whereas, in the former case, the weft thread-flies with considerable speed, namely, practically the same speed as the shuttle has.

' through the shed. The thread, particularly if heavy and/or stiff material is used, constitutes considerable mass and accumulates great inertia during the weft so that"the thread runs after the shuttle and too much thread is supplied so' that means must be provided to remove the excessive amount from the shed. The massaction of the thread is augmented by the air surrounding the weft thread and which develops a considerable air current during and right after the flight of the shuttle and weft thread through 5 the shed. Further, in looms having gripper shuttles, the weft thread runs off comparatively large bobbins also constituting great mass and inertia. If stiff and/or heavy thread material is used, too much thread may be fed into the shed at certain moments, in other cases great resistance must be overcome in order to pull the thread off the supply bobbins. It is an object of the present inve'ntion to provide methods and apparatus which eliminate all disadvantages which are caused by the before stated conditions. An object of the present invention resides in the provision of a loom for weaving in which the tension of the weft threads ispositively controlled, and the shrinkage and character of the 40 fabric can be predetermined by controlling the tension of the individual weft threads.

In looms having grippershuttles, the tension of the weft threads which are, pulled through the Y warp, sometimes against considerable frictional 45 resistance, is often much greater than in looms in which the weft thread runs off the shuttles. In such cases, gripper shuttles could hitherto only be used for producing fabrics which permit great tension of the weft threads. The present inven- 50 tion has for its object to provide weft thread tension control means by which the tension of the weft threads can be positively adjusted, and

January 17, 1934 vision of an apparatus by means of which the length of the weft threads in looms for weavin can be controlled either during or after the weft, i. e., the weft thread is shortened orlengthened during or after the passage of the gripper shuttle through the warp.

Another object of the present invention is to provide an apparatus which assures the lengthening of the weft threads during and after the weft to such an extent that shrinkage of the produced fabric is eliminated.

A further object of this invention is the provision ofv a control apparatus for adjusting the tension of the weft threads in looms for weaving, whereby the provision of special fabric stretchers is rendered unnecessary or only a gentle pull is sufficient for stretching the fabric to maintain the desired width.

Another object of the present invention is to provide a method and apparatus for adjusting the tension of the weft threads in looms for weaving, whereby a particularly tight fabric can be obtained without increasing the impact of the lay whereby, on the contrary, this impact may be reduced, and the warp threads suffer much less, and breaking of warp threads is substantially reduced. I

A further object of my invention resides in the provision of a method and apparatus for controlling the tension of the weft threads in looms for weaving, whereby an adjustable amount of brake action is applied to the weft threads which prevents undesired curling when using much twisted or crape threads and permits faultless weaving of such threads.

Other objects of the present invention will be method and apparatus according to the present invention and will be set forth in the claims and the description relating to the drawings which, by way of illustration, show what I now consider to be preferred embodiments of my invention.

In many cases, it is sufiicient if the weft thread is lengthened only on one side of the fabric after the pick is completed. If the thread'is elastic, the elongation is instantly distributed over the whole width of the fabric. According to the invention, the shuttle may be allowed to travel beyond the edge of the fabric after it has passed through the warp and then be moved back towards the fabric. In such manner, weft threads are used which are longer by the distance which the shuttle has traveled beyond the warp. In looms having gripper shuttles and thread feeders for feeding the thread to the shuttles, addiapparent from the following broad outline of the.

40 a y In such cases and without applying the present invention, the edge of the fabric has an arched thread is then determined by the distance of the point where the gripper engages the thread from the edge of the fabric. Obviously, a special gripper may be used and operated independently of the thread feeder.

The before described means can he applied to both sides of the fabric. The motion of the gripper located at that side from which the thread is fed into the fabric may be started just at the moment when the weft thread is still. moving due "toits own inertia, whereby the additional supply of thread is equally distributed over the. whole width of the fabric, also when using threadmaterial which is not elastic. This distribution I will hereafter be fully equalized by the impact of the lay and'by thegpressure of the warp threads so that homogeneous texture is obtained having only very little or no shrinkage at all.

When making fabrics in which the weft threads are under great tension, it has been found that the weft thread sustains greater tension when stretched after the pick than when applying great tension during the pick. According to the presentinvention, for such cases a special weft thread stretcher is provided outside of the shed which may be operated by an adjustable spring and which appliesa. predetermined tension to each weft thread after the pick. This method is particularly advantageouswhen the weft bobbins do not operate absolutely equally so that the weft threads may run off more easily at certain times and less easily at other times.

configuration. Such faults in the fabric are completely eliminated if the tension of all the weft threads is equalized by the before mentioned weft thread stretcher. The effect of supplying additional weft thread and weft tension may also be combined which is of particular advantage in most cases. The weft threads are first brought to equal tension after the: pick in order to eliminate loops and loosening, and then supplementary thread material of predetermined length is added so that all weft threads have the-same length and tension.

In the drawings:

Fig. 1 is a diagrammatic part cross sectional view of a mechanism for maintaining the weft thread under a predetermined tension during the pick, slackening and/or stretching the weft thread after the pick. I t

Fig. 2 isv a diagrammatic view of part of the mechanism illustrated in Fig. 1, however,'in

another phase'of operation.

Fig. 3 shows another phase of operation of the mechanism illustrated in Figs. 1 and 2.

Fig. 4 is a diagrammatic showing of the mechanism shown in Figs. 1 to 3,. however. in still another phase of operation.

Fig; 5 is a modification of a detail of the mechanism shown in Figs. 1 to 4.

Fig. 6 is adiagrammatic longitudinal cross sectional view of a-pneumatic thread stretcheraccording to my invention.

, Fig. 7 is a diagrammatic transverse sectional view of the thread stretcher shown in Fig. 6

and taken along line 1-1 of Fig. 6.

Fig. 8 is a diagrammatic showing of a mechanical thread stretcher according to my invention.

Fig. 9 is a diagrammatic showing of a thread gripper mechanism for feeding additional thread or stretching the thread.

Fig. 10 is a diagrammatic showing of a comb type weft thread stretcher according to my invention.

Fig. 11 and Fig. 12 are diagrammatic cross sectional views of a lay equipped with a thread stretcher according to Fig. 10 and showing the stretcher in two different phases of operation.

Fig. 13 diagrammatically shows a mechanism for feeding .in additional weft thread after the pick, the figure showing the individual parts in the position during the pick.

Fig. 14 shows the'same'mechanism as illustrated in Fig. 13, the movable parts being in the position after the pick.

Referring more particularly to Figs. 1 to 4 ofthe drawings, the weft thread I is pulled from bobbin it during' the pick of shuttle l. Picking means are not shown as these are not part of the present invention. The weft thread passes through the disc brake II which makes the tension of the thread substantially independent of the running off conditions of the thread off bobbin l3. Thereafter it passes the'loop 45 of the stretching device I 6. 6 indicates the warp threads forming the shed. After theshuttle has arrived at the shuttle receiving box l8 and is held therein by braking means which are not illustrated, the weft thread lays in the shed under equal tension which is substantially due to brake- I. By adjustment of the latter, the tension of the thread during the' pick can be predetermined.

After the pick,the apparatus is in the position illustrated by Fig. 1. Right after the pick, jaws l9 and are closed as shown in Fig.2 and moved towards edge 2| of the fabric into the position shown in Fig. 3. A mechanism which may be used for accomplishing this is shown separately in Fig. 9 and will be described later. On the other side of the fabric, shuttle l is pushed towards the fabric edge 23 by means of pusher 22 (Fig. 3). This causes a slackeningof the weft thread 4 which can beexactiy adjusted by suitable determination of the distance over which Jaws iii-'20 and shuttle-l are moved towards the center of the fabric. For smaller fabrics or fabrics of certain character, only the mechanism on one side may be used for slackening, or the jaw moving mechanism and the shuttle moving mechanism may be used alternately or operated according to a certain predeter- 'chain'hangs on chain wheel 18 which is connected to and driven by the driving mechanism of the loom. This connection is not shown as it is not part of the present invention. Whenever a link having a' projection 14 comes into the fabric edge 23 and the weft thread slackened. The projections of some links may be smaller- 14and other links may not have any projections at all. The slackening of the weft thread is in proportion to the stroke of rod I! which depends on and can be predetermined by the configuration of links 1|. .By these means, various characters of fabric can be obtained. For example, a certain part of the weft threads are slackened and produce crimping and craping, whereas others are stretched producing repp. By proper combination of these various characters of weaving within' the same fabric, a great amount of varieties of patterns can be obtained.

Additional tension may be applied to the weft thread during or after the pick by the means shown adjacent to the disc brake l4. As be- I fore said, the weft thread passes through the eye 45 of the double lever l6/52 which is revolvable around pivot 5|. 'Eye 45 extends into an opening of the loom structure having rounded rims 46 and 41. At a suitable moment, latch 50, which is revolvable around pivot 49 and holds the double lever against spring 53 in a position in which eye 45 extends into the opening, is turned clockwise by means 48 which are not shown in detail and frees double lever l6/52.

Eye 45 then snaps downwards taking the weft thread with it and pulling the weft thread into a loop 46-4541. By proper adjustment of spring 53, the extent of movement of lever l6/52,

the size of the loop and the tension of the weft thread can be predetermined. Disc brake I 4 takes care that no undesired thread is pulled off the bobbin i3. It is obvious that the laws if! and 20 must be open during this action of the thread tensioner [6/52. The double lever is pulled back into starting position by means of chain 80 which is periodically operated by cam 8 i. This cam is rotatably connected to and operated by the loom driving mechanism. This connection is not shown because it is not part of the invention.

The just described thread tensioner may also be operated to act as thread slaokener and to allow a predetermined additional length of weft thread. to pass into the shed. For this purpose, lever l6 and eye 45 are normally in the position shown in Fig. 4. At the moment when an additional supply of weft thread is desirable, the lever is moved counter-clockwise by the means 80 and 8 I.

Fig. shows a modification of the weft thread control described in the foregoing. paragraphs. The thread passes through the three eyes 42, 43 and 44. The eye in the middle-43-is provided with an upward extension I9 which is connected with one end of spring 11, the other end of which is fixed to a stationary part of the loom. Eye 43 also has a downward extension 69 which cooperates with lever 18 which is pivoted to a stationary part of the loom. Lever 78 may be connected to and operated by a moving part of the loom. Such a connection has not been shown as it is not part of the present invention. Eye 43 can be moved downwards against the tension of spring 11 by turning lever 18in counterclockwise direction so that the thread is pulled into the loop 42-, 43', 44 shown by dotted lines.

Figs. 6 and 7 show a weft thread tensioner operated by a current of air produced by blower II and controlled by valve 16. The channel 60 for the weft thread 4 is crossed by the air channel 6|, the end of which is flattened as is obvious from Fig. 7. During the pick, the air current Present ages the other side of abutment 69.

continuously maintains a tension in the weft thread which then forms a small loop as indicated by dotted lines in Fig. 6. As soon as the shuttle is stopped, the weft thread is blown into a larger loop and tension maintained on the thread which would otherwise be loose within the shed and possibly curl due to its own inertia. By adjustment of the air supply to channel 6|, the tension of the thread can also be adjusted.

-. This is done by providing valve 16 in duct 6|.

Fig. 8 shows a mechanical means for maintainis limited and thereby the tension applied to the thread is controlled by the stop member 59' which has the shape of an eye through which the weft thread runs and is provided withconical external surfaces facing jaws 55-56. When these jaws, pulled by the weft thread, run against the conical part of stop member'59, the jaws are opened and thread 4 is freed. Thereupon spring 58 pulls back jaws 55-56 which then close again on the weft thread. Stop member 59 is connected to a mechanism 3 which permits its movement in the direction of the weft thread. Thereby the amount of tension applied to the thread can be adjusted.

Fig. 9 shows in detail the clamps l9 and 20 already mentioned in connection with the description of Figs. 1 to 4 and, in a schematic man, ner; a mechanism which may be used for their operation. Clamp holder 62 which may be identical with the thread giver as described in my shown in solid lines, i. e., inclined to the direc- 'tion of the thread, the jaws are closed. If it is turned clockwise so that it stands perpendicular to the thread, the jaws are spread apart and thethread is free. This clockwise movement is effected whenever one side of abutment 65 runs against the plate spring 63 attached to the end of latch 66. The laws close when spring 63 en- Spring 63 flexes and passes underneath abutment 69 when member 62 moves to the right. At this movement, it pushes thread 4 to the right with the jaws closed feeding additional weft thread to the shed and slackening the thread. Abutment 69 is then also moved to the right and follows member 62 until it touches spring 63 and turns latch 66 clockwise, thereby spreading the laws apart and freeing the thread. Now member 62 can be moved to the left. While spring 63 passes abutment 69 underneath, a further clockwise movement of latch 66 is prevented by nose 64 projecting from member 62.

The mechanism for producing the reciprocating movement of abutment 69 consists of rod 82 moving in bearings 83 and operated by the groove 88 which is driven by the loom driving mechanism. The latter is not shown as it is not subject matter of the present invention. It is obvious that, by suitably designing and operating cams B4 and 81, the apparatus can be used not only for slackening the weft threads. but also for stretching the weft threads. In this case, jaws l9 and 28 are closed when they are farthest to the right and then pull the thread to the left and thereby stretch the weft thread.

Figs. 10 to 12 show a mechanism for progressively applying additional weft thread. 6 are the warp threads in section. 4 is the weft thread. After the weft, arm 29 of a plurality of bellcrank levers 28-29 engages the weft thread and pulls I of the bellcrank lever is shown in Fig. 11.

it downwards in between two adjacent warp threads so that loops are formed. This position The bellcrank levers'are rotatably supported by rod 21 mounted to lay 28. For accommodating arms 29 and the loops of the thread, a longitudinal groove 3| is provided inlay 26. If the longitudinal member 33 which is provided with a plurality of inclined cams 34 engaging arms 28 of the bellcrank levers is moved towards the left, one

" crank lever after the other starting from the right is turned clockwise and loops 32 are formed in the weft thread in the same succession. Since the right end of the weft is heldby, the shuttle and by already formed loops, additional loops to the left can only be formed'by pulling {additional thread from the bobbin which is on the left side. After the loop forming operation is completed, cam .member 33 is moved towards the right and the bellcrank levers all turn counter-clockwise into the position shown in Fig. 12 by the action of spiral springs 30, one end of which is connected to rod 21 and the other to arm 29. .At the then following beating up. of the weft thread, the additional supply of weft-thread is equally distributed over the whole'width of the fabric. If the apparatus is arranged and operated for forming the loops of the weft thread consecutively from the left side towards-the right side, i. e., in the direction of the movement of the shuttle, additional tension may be applied to the thread.

Figs. 13 and 14 illustrate another method of supplying additional weft thread. just at the end of the pick. A buffer member 1 is provided within the shuttle receiving'box 2 which is pushed to I the right by the incoming shuttle and abuts against the one arm lever 35 turning it in a clockwise direction around its fulcrum 36. The

end of lever 35 is connected by a connecting element 3'! with the end of lever 38 which rotates.

member 4| whenever lever 38 is turned clockwise. The connecting member 34 moves to the right upon clockwise operation of lever 35 by the incoming shuttle and not only turns lever 38 clockwise, thereby engaging the weft thread, but

also pulls slide member 4| to the right and there-' by pushes additional weft thread to the right, i. e., into the shed. By adjustment of the length of levers 35 and 38, the amount of additional thread supplied can be definitely controlled. The starting position oflever 35 is determinedby the position of the adjustment screw 15 against which lever 35 abuts whilethe shuttle is on the way. Slide member 4| and levers 35and 38 may be pulled backwards into starting position by a mechanism indicated by the string 24, the roller 25 and the weight i5.

While I believe the above described embodlments of my invention to be preferred embodiments, I wish it to be understood that I do I not desire to be limited to the exact details of .method, design and construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim:

1. In looms for weaving, an apparatus for withdrawing a predetermined length of weft thread for operating said movable member and adapted -to remove said eye from said opening for a predetermined distance andto thereby pull the weft thread through said opening whereby the weft thread forms a loop the extent of which is in proportion to the length of the thread withdrawn from the shed substantially as described.

1 2. In looms for weaving, an apparatus for supplyinga predetermined length of weft thread to the shed after completion of the weft insertion comprising a stationary part adapted to slidin y carry the weft thread and having an opening and a movable member, said movable member having an eye through which the weft thread runs during the weft insertion into the shed, said eye being remote from said opening whilethe weft thread isbeing inserted into the shed, a means for operating said movable member andadapted to move said eye into said opening and. to thereby permit the weft-thread, which formed a loop the size of which is in proportion to the distance of said eye from said opening, to move into the shed, whereby an additional amount of weft thread is available which is in proportion to the size of the formerly formed loop, substantially as described.

. 3. In a loom for weaving, an apparatus for feeding into-and withdrawing a predetermined amount of weft thread from the shed comprising a reciprocable .thread holder having a thread channel therein, movable jaws carried by said thread holder for gripping the thread protruding from said holder, jaw operating means associated with said holder and actuable to close said jaws upon the thread and to open said jaws,

and reciprocable means actuating said jaw oper- 'ating means'w hereby, due to the difference of the reciprocating motion of:said thread holder and said reciprocable means, the distance and direction is determined by which the thread is carried by the .holder when the jaws are closed.

4. In looms for weaving, an apparatus for withdrawing a predetermined length of -weft thread from the shed after completion of the weft insertion comprising a stationary part .5

adapted to slidingly carry the weft thread and having an opening and a movable member, said movable member having an eye through which the weft thread runs during theweft insertion into the shed, said eye extending into said opening while the weft thread is inserted into the shed, a mechanism comprising spring means for operating said movable member and adapted to yieldingly remove said eye from said opening and to thereby yieldingly stretch and pull the weft thread through said opening,- whereby the weft thread forms a loop the extent of which is in proportion to the length of the thread withdrawn from the shed, substantially as described.

5. In looms for weaving, an apparatus for supplying a predetermined length of weft thread to the shed after completion of the weft insertion comprising a stationary part adapted to slidingly carrythe, weft thread and having an opening against the action of said means and to thereby permit the weft thread, which formed a loop the size of which is in proportion to the distance of said eye from said opening, to move into the shed, whereby an additional amount of weft thread is available which is in proportion to the size of the formerly formed loop, substantially as described.

6. In looms for weaving, an apparatus for con trolling the length of the weft thread inserted .into the shed comprising a stationary member adapted to slidingly carry the weft thread and having an opening, a movable member having an eye through which the weft thread runs during the pick, and means for removing said: eye from said opening, whereby theweft thread is pulled into a loop and withheld from entering the shed and for moving said eye into said opening, whereby weft thread withheld from' the shed is permitted to enter the shed.

7. In looms for weaving, an apparatus for controlling the length cf the weft thread inserted into the shed comprising a stationary member adapted to slidingly carry the weft thread and having an opening, a movable member having an eye through which the weft thread runs during the pick, and means for removing said eye from said opening, whereby the weft thread is pulled into a loop and withheld from entering the shed and for moving said eye into said opening, whereby weft thread withheld from the shed is permitted to enter the shed, said means comprising yielding means adapted to yieldingly stretch the weft thread.

8. In a loom for weaving, an apparatus for feeding apredetermined amount of weft thread into the shed and for withdrawing it from the shed comprising a reciprocable member adapted to slidingly carry the weft thread, movable jaws mounted to said member, jaw operating means movably connected with said member and adapted to close said jaws upon the thread and to open said jaws, and actuating means for ac tuating said jaw operating means.

RUDOLF ROSSMANN.

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