US3900051A

US3900051A - Apparatus and method for supplying pile warp threads in a loom for weaving terry cloth

Info

Publication number: US3900051A
Application number: US457267A
Authority: US
Inventors: Robert Bucher
Original assignee: Sulzer AG
Current assignee: Sulzer AG
Priority date: 1973-04-06
Filing date: 1974-04-02
Publication date: 1975-08-19
Anticipated expiration: 1992-08-19
Also published as: DE2318326B2; CH564621A5; DE2318326A1; AT324982B

Abstract

The pile warp threads are passed through a storage means including a movable deflecting beam and two fixed bars which serve to form a thread reserve between two full beat-ups of the loom. A clamping beam cooperates with the bar of the storage means closest to the shed to clamp the threads during the time intervals between two successive beat-ups or between successive full and partial beat-ups. The opening of the clamping beam occurs simultaneously with the release of the thread reserve from the storage means to allow delivery of the pile warp threads without tension to the shed. This obviates any backward pull-out of the formed loop in the cloth.

Description

United States Patent Bucher 1 Aug. 19, 1975 [54] APPARATUS AND METHOD FOR 1,539,178 5/1925 Giardino..... 139/102 SUPPLYING PILE WARP THREADS IN A 1,665,274 4/1928 Neisler.... 139/25 3,360,012 12/1967 Erkes 139/102 LOOM FOR WEAVING TERRY CLOTH Inventor: Robert Bucher, Winterthur,

Switzerland Assignee: Sulzer Brothers Limited,

Winterthur, Switzerland Filed: Apr. 2, 1974 Appl. No.: 457,267

Foreign Application Priority Data Apr. 6, 1973 Switzerland 4914/73 US. Cl 139/25; 139/102 Int. Cl. D03D 39/22; DO3D 49/12 Field of Search 139/24, 25, 26, 97, 100, 139/101,102,105

References Cited UNITED STATES PATENTS 3/1884 Charcot 139/102 Primary Examinerl-lenry S. Jaudon Attorney, Agent, or FirmKenyon & Kenyon Reilly Carr & Chapin [5 7 ABSTRACT The pile warp threads are passed through a storage means including a movable deflecting beam and two fixed bars which serve to form a thread reserve between two full beat-ups of the loom. A clamping beam cooperates with the bar of the storage means closest to the shed to clamp the threads during the time intervals between two successive beat-ups or between successive full and partial beat-ups. The opening of the clamping beam occurs simultaneously with the release of the thread reserve from the storage means to allow delivery of the pile warp threads without tension to the shed. This obviates any backward pull-out of the formed loop in the cloth.

14 Claims, 5 Drawing Figures PATENTEDAUG-I ems .051

sum

1 or 4 WTENTED AUG-1 91975 .900.051

saw 3 OF 4 PATENTEI] A1181 91975 sum mg APPARATUS AND METHOD FOR SUPPLYING PILE WARP THREADS IN A LOOM FOR WEAVING TERRY CLOTH This invention relates to an apparatus and method for supplying pile warp threads in a loom for weaving terry cloth.

Numerous methods and corresponding loom con structions are known for the production of terry cloth with woven-in pile loops projecting from one or both sides of the basic weave. With many types of machines the pile loops are made as a so-called nap. The nap is formed by the superimposition of a withdrawal movement in the weaving plane in the direction in which the cloth runs through the machine (that is, an advance of about the spacing between two weft threads in the finished fabric after each insertion of a weft) and a relative movement between the foremost reversal point of the reed and the apex of the shed. Here, the individual weft threads are beaten up in an alternating sequence to either directly adjoin the finished cloth (full beat-up) or to be spaced from the cloth at a spacing of some 0.5 to 2 centimeters (cm) (partial beat-up). If a full beatup is followed by two or more partial beat-ups, then the pile warp threads and the ground warp threads are initially bound in by the weft threads which are inserted with partial beat-ups at a distance from the finished cloth. At the next following full beat-up, the weft threads inserted with the partial beat-ups are pushed forward along the tensioned ground warp threads, until they also adjoin the finished cloth. Because the pile warp threads are under less tension than the ground warp, the bound-in pile warp thread length is thus pushed forward by means of and with the weft threads and piled up into nap or pile loops. After this, the process is repeated for as long as pile cloth is to be woven.

If there is to be a temporary weaving of smooth cloth (i.e. without nap) as is, for example the case in weaving towels or the like, then only full beat ups are made, and the tension of the pile warp is kept at a normal value corresponding approximately to the tension of the ground warp so that no loops can form.

In order to ensure that the last-formed pile loops or nap are not drawn backward because of excessive thread tension during or after the full beat-up, it has been known to briefly decrease the thread tension of the pile warp at the beginning of the full beat-up. This is accomplished by releasing a brake on the pile warp thread beam. However, this has not been efficient because of the moment of inertia produced by the great mass of the pile warp beam. Furthermore, the moment of inertia changes with the progress of the weaving of the pile warp.

Other types of looms have been known'to use a special pile warp slackening device, which during a full beat'up of the reed briefly accelerates the pile warp beam. Also, use has been made of a sort of Sand beam or a pair of rollers, through which the pile warp is rapidly drawn off the warp beam at a suitable instant or pulled out of a device for keeping the thread tension constant in order to make the shed practically tensionless. With this arrangement, there is the difficulty of adapting the speed and amplitude of the supplementary advance of the set of pile threads in optimum fashion to the conditions of the weaving process, that is, to the provided length of pile loops, or for example changing over to another weaving pattern, or to the requirements of another grade of yarn, so that the pile warp threads may be delivered practically without tension and without becoming slack at a full beat in all cases.

Accordingly, it is an object of the invention to permit an advance of pile warp threads and the maintenance of tension in such threads in infinitely variable fashion and by simple means in a terry cloth loom.

It is another object of the invention to produce pile loops in terry cloth without having to periodically brake the rotation of a pile warp beam.

It is another object of the invention to prevent a backward pull-out of a pile loop during formation in a terry cloth.

It is another object of the invention to maintain pille warp threads at a tension corresponding to the ground warp threads during partial beat-ups or when weaving smooth fabric while delivering the pile warp threads substantially without tension and without slack during full beat-ups.

Briefly, the invention provides an apparatus and method of supplying pile warp thread in a terry cloth loom in a manner to prevent pull-out of pile loops during weaving.

The apparatus comprises a pile warp release means which cooperates with a pile warp beam for delivering pile warp threads at a constant tension to a shed in the loom, a storage means downstream of the pile warp release means and a clamping means between the storage means and shed. The storage means functions to form a reserve of pile warp threads upstream of the shed in the time interval between successive full beat-ups of the loom while the clamping means functions to selectively or periodically release the reserve from the storage means during a full beat-up in order to supply a measured length of pile warp thread in a substantially untensioned state. During the build up of the pile warp reserve, the clamping means can be locked so as to prevent release of the pile warp. This allows the pile Warp between the clamping means and the beat-up point in the shed to be under tension. The clamping means, however, may also be released during partial beat-ups. This allows the pile warp between the pile warp beam and the beat-up point to be under tension while the reserve is maintained by the storage means.

The storage means is constructed, for example, of a pair of fixed parallel bars which extend across the width of the pile warp threads and a movable deflecting beam parallel to the bars which is able to move between the bars from a preset position for the formation of reserve loops in the pile warp threads. That is, as the deflecting beam moves into coincidence between and with the fixed bars, the threads are deflected out of a straightline path and deviate in a looped or curved pattern between the beam and bars. The storage means also includes a guide means for guiding the deflecting beam towards and away from the bars, a cam drive for synchronizing the movement of the beam with the movement of a reed of the loom and a linkage between the drive and guide means to transfer the motion forces. The drive may also have an adjustable coupling element which is dis-engagable from the reed drive so that the drive can be disengaged to disengage the storage mens from operation. The cam drive serves to move the deflecting beam into a position of greatest deviation from a preset position immediately before a full beatup so as to form the thread reserve and into a position of least deviation during a full beat-up.

The clamping means is constructed, for example, of a clamping beam which is movably mounted between one of a thread releasing position and a thread clamping position. In the clamping position, the beam is pressed against the fixed bar of the storage means which is downstream of the deflecting beam. In order to move the clamping beam, the clamping means includes a cam drive for synchronizing the movement of the beam with the reed of the loom. This cam drive may also include a dis-engagable coupling element by which the beam can be locked at least in the thread releasing position. The cam drive can also be constructed to have the clamping beam bear on the bar of a storage means under a prestress between reed beats while being released during full beat-ups.

The coupling of the cam drive of the deflecting and clamping beams with the reed drive allows an exact synchronization of their functions to be obtained with the beat-up of the reed, as well as a synchronization of the chronological progress of the formation of the reserve supply of pile warp threads and the control of the release of the threads.

In a particularly advantageous form of construction, the cam elements of the deflecting beam drive and of the clamping beam drive may be mounted on the same camshaft. This substantially simplifies the construction of the apparatus.

In another form of construction, a separate cam drive for the clamping beam may be omitted. In this case, a drive element of the deflecting beam has an abutment means in operative connection with a corresponding abutment means on a drive element of the clamping beam, and the clamping beam is operated via this abutment means through the deflecting beam drive. In this way, the drive mechanism for the clamping beam is substantially simplified. The drive cams for the deflecting beam can be made so that the clamping beam holds the set of pile warp threads firmly during the storage process but if necessary, during full beat-up and, on occasion also during partial beat-up, can be briefly relased through the deflecting beam drive.

Finally, one off the aforesaid forms of construction mayy have the additional characteristic that both the fixed bars of the storage means and also the movable deflecting and clamping beams are mounted at both ends in bearing plates, which, in turn, are each fastened on one of the two side uprights of the loom and are adjustable as to their height and their distance from the apex of the shed. By means of such an arrangement, the run-in of the pile warp threads into the weaving plane can have optimum adjustment.

If, as may for example be the case in weaving towels, a piece of smoothly woven fabric is to be produced following a certain length of napped fabric, then the de fleeting beam may be locked in the position for least deviation of the set of pile warp threads, and the clamping beam may be locked in the release position through the disengagement and locking of the corresponding coupling elements.

In order to completely eliminate the risk of a backward pull-out of the pile loops, the intermediate storage means can be combined with a pile warp releasing device wherein the pile warp beam has a relaxing brake which is adjustable as a function of the diameter of the wound-on pile warp to effect a constant tension in the paid-off threads. In this embodiment, with the clamping means closed, upon movement of the deflecting beam into a new position. the pile warp beam starts turning after overcoming the braking force due to the pull exerted on the set of pile warp threads during the storing process.

The method of the invention includes the steps of building up a measured reserve of pile warp threads upstream of the shed between each two successive full beat-ups and of releasing the measured reserve during a following full beat-ups substantially without tension to prevent a backward pull out of the pile warp threads from the produced loops. The reserve of pile warp threads may also be released during partial beats to be introduced into the weaving operation while being held under tension.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a simplified schematic representation of a known pile thread release or relaxing means which is adjoined, in the direction in which the threads move, by a pile warp thread supplying apparatus in accordance with the invention;

FIG. 2 graphically illustrates the time-base progress of the movements of the reed and of the clamping beam, as a function of the angle of rotation of the main shaft of the loom for an operative cycle consisting of one full beat-up and two part beat-ups of the reed, and also the full beat-up of the following cycle in accordance with the invention;

FIG. 3 schematically illustrates a known process for forming a nap through a sequence of-full beat-ups and only partial beat-ups of the weft threads;

FIG. 4 illustrates a further embodiment of the apparatus wherein the clamping beam is operated by the drive of the deflecting beam; and

FIg. 5 illustrates a simplified representation of a combination of the storage means of FIG. 4 with a pile warp thread release means formed of a brake which can be adjusted to a constant thread tension and which depends on the withdrawal of the pile warp threads through the deflecting beam.

Parts that are of themselves known, or that are not needed for an understanding of the invention, are omitted from the drawings. Further, parts which have the same function in the various figures carry the same reference numerals, and are marked with a special index when the description needs a different designation. Stationary parts, such as shafts and so forth, are emphasized by hatching.

Referring to FIG. 1, a pile warp beam 1 shown in its high position is mounted to turn about a stationary axle. The beam 1 contains a set 2 of pile warp threads which can be drawn off under practically constant tension. A warp release means 3l5 for delivering the warp threads at a constant tension to a shed consists of the following parts: a tension roller 3 which is able to turn on the free end of a lever 5 which pivots about a fixed axle 4; a tension spring 7 which is connected to the lever 5 to tension the pile warp threads before they are conducted to a further fixed-location deviating roller 6 to form a loop which is variable in the sense indicated by the double-arrow 8; a link 9 which is hinged to one end of the lever 5 and is hingedly connected with an end ofa second lever 10, which, in turn, is pivotably mounted on a fixed axle 11; a pressure'plate 12 carried on an end of the lever 10 and which, through the intermediary of a compression spring 13, tensions a brakeband 14 about the warp beam; and an adjusting nut which serves to adjust the thread-tension of the pile warp 2 to the desired value. The way in which this arrangement operates is as follows: When the pile warp 2 is pulled, the tension in the threads becomes increased, and the tension-roller 3 is raised against the force of the tension-spring 7. The pivoting movement of the lever 5 is then transmitted through the link 9 to the lever 10, so that the pressure-plate 12 on the spring 13 is decreased. The brake-band 14 becomes loosened, and releases the pile warp beam 1, from which, however, only as much pile warp becomes unwound as can, under the influence of the tension spring 7, lower the roller 3 again into its original position, while the thread tension re-assumes its original value. Warp release means of this kind are known per se.

An intermediate storage means is located downstream of the warp release means 3-15 through which the set of pile warp threads pass. This storage means includes a pair of fixed-

location parallel bars

21, 22 and a deflecting beam 23 running parallel to the

bars

21, 22 and movable transversely of their lengthwise direction. The beam 23 is movable into the plane of the

bars

21, 22 to deflect the threads to form a variable reservesupply loop. The beam 23 is fastened to the free end of a guide means such as a lever 26 which is able to pivot about the fixed-location axle 24, as indicated by the double-arrow 25, and move in a path towards and away from the

bars

21, 22.

The storage means also includes a cam drive 2737 for synchronizing the movement of the beam 23 with the movement of a reed (not shown) of the loom and a linkage 35 which connects the drive 27-34 to the lever 26. The cam drive includes a cam element, i.e. a cam disk 29 which is mounted on a drive shaft 28 to turn in the direction indicated by the arrow 27 and a roller 30 which runs on the cam disk 29 and is mounted on one arm ofa double-lever 32 which pivots about the axle 31. In addition, a tension-spring 33 connected between the lever 32 and a fixed point holds the roller 30 in contact with the cam-disk 29. The other arm of the double-lever 32 carries ajoint 34 which is adjustable in an elongated slot. The linkage 35 connects lever 32 with the other end of the pivoting lever 26 carrying the deflecting bar 23.

The present example of construction corresponds to a weaving process for producing a so-called three-weft texture, that is, a working cycle in which each two partial-beat-ups of the reed are followed by a full beat-up. In this case, the drive shaft 28 turns at a third of the speed of the main drive-shaft (not shown) of the loom. Consequently, the cam-disk 29 has only one lobe on the periphery over which the roller 30 runs at each full beat-up of the reed.

A clamping means is also mounted between the storage means and the shed. This clamping means includes a clamping beam 41 of a rigid U-shaped profile, over which an elastic hose of damping material, such rubber, synthetic material, or felt, is stretched for the purpose of not damaging the pile weft threads 2 which are clamped and held between the clamping beam 41 and the lower bar 22 of the storage means. Of course, this beam 41 may just as weel be made in some other known way and is regarded as advantageous.

ln order to move the beam 41 between a release position and a clamping position, as shown, the clamping means includes a cam drive for synchronizing the movement with the reed. This cam drive includes a cam element or disk 29' mounted on a drive shaft 28 which turns, as indicated, by the arrow 27, at a speed reduced to one third that of the main shaft. It is therefore easily possible to dispose the two cam-

disks

29, 29, on a common shaft, although for greater clarity they are shown mounted on two

different shafts

28, 28 in FIG. 1. The drive also includes a double-arm lever 44 which is fastened to the beam 41 and which is able to pivot by the double-arrow 42 about an axle 43, and is, under the action of a tensile spring 45 connected between the lever 43 and a fixed point, subjected to a prestress tending to turn the beam 41 clockwise to press the beam 41 against the bar 22. The lever 44 carries a roller 46 at one end which is biased toward the coupling element 29.

In the illustrated example of construction, it is assumed that the clamping beam 41 is released at each beat-up of the reed and that the drive-shaft 28' runs at a third of the speed of the main drive-shaft of the loom. Thus, the corresponding coupling element 29 must have three lobes, 120 apart. The roller 46 will then, at each rotation of the shaft 28, be raised three times, i.e. at each beat-up of the reed, and the clamping beam 41 will be brought into the release position, in which the beam 41 is out of contact with the bar 22 and the pile warp 2. The cut-outs between the lobes of the cam-disk 29' are made so deep that the lever 44 is pivoted clockwise under the influence of the spring 45 until the clamping beam 41 is pressed by the full force of the spring 45 against the bar 22, clamping the set 2 of pile warp threads tightly. A spacing 47 thus occurs between the roller 46 and the bottom of the cut-outs in the element 29.

The operation and the chronological cooperation of the beat-ups of the reed, of the pile warp intermediate storage means 21 to 35, and of the clamping means 41 to 46, may be explained as follows, with reference to FIGS. 2 and 3:

Referring to FIG. 2, the curve 61 shows schematically the chronological progress of the swinging movement of the reed 62, according to the double-arrow 63 shown in FIG. 3 as a function of the angle of rotation during three revolutions of the main drive-shaft of the loom, or during one revolution of the

drive shafts

28, 28 for operating the deflecting and clamping beams. Between 0 and the reed 62 (FIG. 3) has fully beaten up the weft thread 64v which is situated to the left, as viewed, of the previously only partially

beatenup Weft threads

64t and 64t'. As shown, the weft threads 64i' 64z, 64! have been pushed to the right in the direction of the arrow 66 along the taut warp threads 65, 65' and brought into contact with the finished fabric 64v, 64: 64%, 64v situated still farther to the right. The pile loop 217 thus becomes formed. During the next rotation of the main shaft, between 360 and 465, first of all the first weft thread 641 of the next operative cycle is initially brought to a point at a spacing 2a from 64v Then there follows, at 720 to 825, the second partially beaten-up weft thread 64!, and this, namely for improving the texture of the ground warp without a change of shed.

FIG. 3 shows approximately the l080 instant, that is. the beginning of the next full beat-up 1' at which the reed 62 beats the weft thread 64v completely into the shed 67. At this time, all three weft threads of this cycle, 641,, 64m, and 64r become bound into the finished fabric, and the length 20 of the pile warp thread 2 forms the next loop 212 Curve 72 (FIG. 2) shows schematically a movement of the clamping beam 41, during which this beam, at each beat I, I, t of the reed, and at least during the forward movement of the reed 62, i.e. during approximately the first 60 of each rotation of the main shaft, is brought into the release position. This permits the withdrawal under tension (during partial beat-ups) and the untensioned delivery (during full beat-ups) of the pile warp threads during the progress of the weaving. Curve 710 shows the movement of the clamping beam 41 when the beam is released only during full beat-ups, while remaining closed during partial beat-ups as is for example the case in FIG. 5 with the cam-disks 29c, 29c. of course it is also possible, with a construction according to FIG. 1, to replace the cam-disk 29 having three lobes spaced 120, by three cams staggered l relatively to one another, so as to obtain a clamping beam movement according to 71a. Thus, the clamping beam 41 serves to clamp the pile warp threads in place at a point between the measured reserve and the shed during building up of the measured reserve.

As shown by experience, in most cases it is possible to do without a release of the clamping beam during partial beat-ups, because the normal withdrawal during an operating cycle of three or four weft insertions scarcely exceeds the order of magnitude of l millimeter (mm). Thus, a corresponding stretch of the fabric between the shed apex and warp beam can occur without noticeable increase of the warp thread tension, due to the elasticity of the warp threads.

The

curves

72 and 72b show the movement (doublearrow in FIG. 1) of the deflecting beam 23 for the formation of the reserve-supply loop of pile warp threads during a three-wefts cycle, this being for the two

cam forms

29 and 29a respectively. in the case of the first form 29 and the curve 72, the reserve supply of thread is uniformly formed during the complete duration of the three reed-beats of the cycle shortly before the full beat v; has reached its maximum. In this form of construction, the clamping beam 41 is normally not released during the partial-beaats in order to avoid a backward pull-out of the pile loops. The clamping beam movement thus corresponds to the curve 71a in FIG. 2. It is however entirely possible to briefly release the clamping beam 4], as shown by curve 71, during each partial-beat t t,'. In practice, this has no marked influence on the loop formation, since the pile warp threads are subjected to their normal tension, maintained by the pile warp threads release means 3 to 15, which approximately corresponds to the tension of the

basic warp threads

65, 65, and ensures good binding between partially-beaten weft threads 64! 641, and the pile warp threads 2. Even when the reserve-supply loop is only partly formed round the deflecting beam and with the clamping beam 41 released, the length of pile warp threads needed for binding in the partially beaten up weft threads 641,, 641,, can be pulled off, corresponding to the normal withdrawal of the fabric, by sliding round the deflecting beam 23. It is moreover also easily possible to provide short steps in the upward slope of the cam disk 29 in accordance with curve 72a and during the part-beat-ups I I, for the purpose of briefly interrupting the storage process.

During the full beat-ups v that is from about l()8() to l l40 of the main drive shaft, the deflecting beam drops bak to its zero position so rapidly that the pile warp thread release means 3 to 15 (FIG. 1 because of 5 its inertia, is not capable of compensating the resultant decrease of thread tension. During the full beat-up, therefore, the set 2 of pile warp threads in FIG. 3 is practically without tension, and the thread length 2a is not pulled out backward during the beat up of the weft threads 641,, 641, and 64v so that normally a new loop or nap 2b can form.

In the case of curve 72b, corresponding to cam-disk 29a, the deflecting beam 23 remains in a position of rest up to 825, that is up to the beginning of the second partial-beat-up. The beam 23 only begins to form the reserve-supply loop, as with curve 72, just before the full beat-up reaches a maximum. With a movement progressing in accordance with 7212, no deviation or only a slight deviation of the pile warp threads 2 occurs during the partialbeat-ups. As a result, the threads 2 are better protected from damage during passage through the intermediate storage means than when running according to curve 72, and the slight frictional resistance at the deflecting beam 23 is completely eliminated.

In order to weave smooth fabric at various intervals, i.e. fabric without pile loops, the loom is changed over, either manually or by some suitable control device, in such a way that the reed makes only full beat-ups. At the same time, the pile warp thread supply apparatus is put out of operation. This change-over can be effected by any suitable known coupling element, such as a notshown disengagable coupling in the

drive shaft

28 or 28, or through an axial shift or the cam-

disks

29, 29, on the

shaft

28 or 28, or can be effected in some other way. The only important requirement is that after the uncoupling of the deflecting beam 23, for example outside the range of the

bars

21, 22, and without contacting the set 2 of threads, the clamping beam shall remain locked in the release position, so that the supply apparatus remains switched out during smooth weaving and the weaving process is not influenced.

Referring to FIG. 4, the clamping beam 41 need not have a separate drive mechanism, but can be controlled or operated by the drive of the deflecting beam 23'. As shown, it is possible to replace the cam-drive 27 to 33 of FIG. 1, for example, by a positively-operating double-

cam

29b, 29b, and double-roller drive 30', 30 of a type known of itself. The

curves

72c and 72d of FIG. 2 serve to explain the swinging movement 25 of the deflecting beam 23 of FIG. 4, and correspond to developments of the control cam-

disks

29b, 29b disposed on the common drive shaft 28", for both constructional variants, one for only during full beat-ups v (72c) or one during all the reed beat-ups v, r, 1 (72d).

The construction shown in FIG. 4 compels the

rollers

30, 30", which roll over the cam-

disks

29b, 29b, to impart a swinging movement to the deflecting beam 23, over the

linkage

32, 34, 35, 26', the instanta- 60 neous motion of which is in accordance with curve 72d.

At suitable places, stops

abutments

51, 51, are disposed on the rear edge of the deflecting beam 23' and on the pivoting lever 44 of the clamping beam 41'. When the lever 26' swings clockwise about axle 24' as indicated by the double-arrow 25 then at a certain instant, which can be adjusted, the stop 51 encounters the counter-stop 51, so that the lever 44' is then carried along against the action of the tension spring 45.

This also occurs in a clockwise direction about the axle 24'. Thus, the clamping beam 41' is released. Therefore, the curves 72c and 72:1 show a brief downward deviation at the beginning of each reed beat-up r, and z, 1 corresponding to the release portions of the clamping beam curves 71 and 71a.

In order to form the desired thread reserve-supply loop, the lever 26', and the deflecting beam 23 are swung back again counterclockwise immediately upon completion of the full beat v, in order to obtain the curve 720 and, for the curve 721], after completion. of the second partial-beat-up 1,. The lever 44' follows this movement until the clamping beam 41 with the entire force of the tension'spring 45, against the bar 22, and the stops 51, 51', become separated again. The set 2 of pile warp threads is thus, as in FIG. 1, held fast on the shed side of the intermediate storage means storer. During the formation of the reserve-supply loop, the threads can therefore become pulled along only from the warp-beam side. thus, there is no danger that the thread length 2a, or that the previously formed pile loops 2b, will become pulled backward out of the fab- FIG. 4 further shows an example of obtaining an adjustable mounting of the pile warp threads supply apparatus in the loom. According to this example (other known forms may in some cases achieve the same purpose), both the fixed bars 21, 22 and the movable deflecting beams 23, 23' and/or clamping

beams

41, 41 are mounted at both ends in bearing plates 55, which are in their turn fastened to one of the side uprights 56 of the loom by a clamping screw 58 passing through a slotted hole 57 in the plate 55. Due to the slotted

holes

57, 57, provided in the bearing plate 55 and in the link 35', the spacing between the fixed bar 22 and the shed apex 67 can be changed within certain limits. The height of the supply apparatus can also be adjusted, through adjusting

screws

59, 59, for the purpose of ensuring entry of the set 2 of pile warp threads into the weaving plane under optimum conditions, without having to make the

drive shafts

28, 28, 28" adjustable. As

shown, the screws 59, 59' are secured in suitable lugs on the loom frame to allow vertical adjustment of the bearing plate 55.

FIG. 5 shows an intermediate storage means and clamping beam arrangement 21 to 45, which is identical with that of FIG. 4 with the exception of the camdisks 29c. 290, which trigger a deflecting-beam movement according to curve 720 and a clamping beam movement according to curve 711: (FIG. 2). Instead of the pile warp release means as shown in FIG. 1, controlled by a pivoting roller 3 and a spring 7 which enables the spring tension to be kept particularly constant, the pile warp beam is only braked and is set rotating directly through the pull exerted on the pile warp threads, in accordance with the storage operation during the deviation of the deflecting beam 23. The warp beam 1 has a gearwheel 17, which, via an intermediate wheel 17, is coupled to a gearwheel 17 fastened on a brake-disk 18. The brake-band 14 is connected over a spring 13' with the free end of a pivoting lever IO mounted on the pivot-pin I1, and carries a measuring roller 16 at the opposite end which, under the action of the spring 13, rests upon the rolled-up pile warp. The position of the lever 10 and of the measuring roller 16 shown by solid lines corresponds to their position with a full roll; and the dotted-line position 10'', I6"

is assumed when the pile warp beam 1 is without a roll. In a known way. with such an arrangement, it is possi ble to compensate for the effect of the decreasing roll diameter within certain limits during the weave-off, and to keep the thread tension of the set of pile warp threads constant, though not with the same accuracy as in the case of the warp reduction of FIG. I. In the position 10', 16, of the pivoting lever, the spring 13 is greatly tensioned. The braking force of the brake-band 14 is thus greater than for the position l0", 16', with which, corresponding to the smaller effective radius, a smaller braking moment must be exerted on the pile warp beam 1 in order to maintain the same spring tension.

At the swing back of the deflecting beam 23' for opening the clamping device 41 to 45, S1, 51', in each case, shortly before a full beat-up v of the reed, the reserve-supply loop of the intermediate storage means becomes completely released, and the pile warp threads can be pulled away, untensioned, to form the pile loops. A pull-back of the pile warp threads is thus positively and at all times avoided.

The invention is not limited to the described examples of construction. In particular, machine elements of kinds other than here illustrated but which perform the same function, may be used, provided that the scope of protection defined in the claims is not affected. In particular, the pile warp release means 3 to 15, or 10 to 18, may be replaced by some other tension-retaining construction. The pile warp beam may also be installed in a low position. The

drive shafts

28, 28', 28 may, if desired, run at other speeds. The fixed and movable deflecting and clamping beams may have some other profile. The drive and controlling means may operate on some other principle, for example by electromagnetic means. Instead of the spring force of the

springs

7, 13, 33, 45 the force of gravity or some other force may be used. The chronological progress of the deflecting movements may deviate in details from the curves shown in FIG. 2, without thereby affecting the process of the invention.

What is claimed is:

I. An apparatus for supplying pile warp threads in a loom for weaving terry cloth comprising a pile warp release means for delivering pile warp threads at a constant tension to a shed;

a storage means downstream of said pile warp release means for forming a reserve of pile warp thread upstream of the shed between successive full beat-ups of the loom; and

a clamping means between said storage means and the shed for selectively releasing the reserve of pile warp thread from said storage means during a full beat-up to supply a measured length of pile warp thread in a substantially untensioned state.

2. An apparatus as set forth in claim 1 wherein said clamping means is releasable during partial beat-up between full beat-ups of the loom.

3. An apparatus as set forth in claim 1 wherein said storage means includes a pair of fixed parallel bars ex tending across the width of the delivered pile warp threads and a movable deflecting beam disposed in parallel to said bars to move between said bars from a preset position for the formation of reserve loops in the pile warp threads.

4. An apparatus as set forth in claim 3 wherein said storage means further includes guide means for guiding 1 1 said deflecting beam in a predetermined path towards and away from said bars, a cam drivefor synchronizing the movement of said deflecting beam with a reed of the loom. and a linkage between said cam drive and =ately before a full beat-up and into a position of least deviation from said present position during a full beat- 6. An apparatus as set forth in claim 3 wherein said clamping means includes a movably mounted clamping i beam disposed between one of a releasing position and Y a clamping position, said clamping beam being pressed against said bar downstream of said deflecting beam when in said clamping position.

7. An apparatus as set forth in claim 6 wherein said clamping means includes a cam drive for synchronizing the movement of said clamping beam with a reed of the loom, said cam drive including a dis-engagab'le coupling element whereby said clamping beam can be locked in said releasing position.

8. An apparatus as set forth in claim 7 wherein said cam drive holds said clamping beam in said releasing position during a full beat-up and in said clamping position between full beat-ups.

9. An apparatus as set forth in claim 7 wherein said storage means further includes a cam drive for synchronizing the movement of said deflecting beam with the reed of the loom, said cam drive including a disengagable cam disk element mounted on a common cam shaft with a cam disk of said cam drive of said clamping means.

10. An apparatus as set forth in claim 6 wherein said storage means includes a first drive element for moving said deflecting beam and a first abutment on said drive element, and wherein said clamping means includes a second drive element for moving said clamping beam and a second abutment on said second drive element for abutting said first abutment after movement of said deflecting beam towards said preset position to move said first abutment and said clamping beam to said releasing position.

11. An apparatus as set forth in claim 10 which further comprises a pair of bearing plates mounting said bars and beams therein, at least one upright in the loom and means for adjustably mounting said bearing plates on said upright vertically and horizontally relative to the apex of the shed.

12. An apparatus as set forth in claim 1 wherein said pile warp release means includes an adjustable release brake, said brake being adjustable as a function of the diameter of wound-on pile warp on a pile warp beam to impart a constant tension to the paid-out pile warp threads. said brake being operable to permit unwinding of the pile warp threads in response to a preset tension in the pile warp threads between said storage means and said pile warp beam while said clamping means is closed to permit formation of the thread reserve.

13. A method of supplying pile warp threads in a loom for weaving terry cloth wherein the cloth is formed upon beating-up successive weft threads in a shed in a sequence of partial beat-up and full beat-ups, said method comprising the steps of building up a measured reserve of pile warp threads upstream of the shed between successive full beatups; clamping the pile warp threads in place at a point be tween said measured reserve and the shed during building up of the measured reserve; and

releasing the measured reserve of pile warp threads during a following full beat-up substantially without tension therein to prevent a backward pull out of the pile warp threads from loops produced thereby.

14. A method as set forth in claim 13 which further comprises the step of withdrawing the pile warp threads during said partial beat-ups while retaining the pile warp threads under tension and while maintaining said reserve. a

Claims

1. An apparatus for supplying pile warp threads in a loom for weaving terry cloth comprising a pile warp release means for delivering pile warp threads at a constant tension to a shed; a storage means dOwnstream of said pile warp release means for forming a reserve of pile warp thread upstream of the shed between successive full beat-ups of the loom; and a clamping means between said storage means and the shed for selectively releasing the reserve of pile warp thread from said storage means during a full beat-up to supply a measured length of pile warp thread in a substantially untensioned state.

3. An apparatus as set forth in claim 1 wherein said storage means includes a pair of fixed parallel bars extending across the width of the delivered pile warp threads and a movable deflecting beam disposed in parallel to said bars to move between said bars from a preset position for the formation of reserve loops in the pile warp threads.

4. An apparatus as set forth in claim 3 wherein said storage means further includes guide means for guiding said deflecting beam in a predetermined path towards and away from said bars, a cam drive for synchronizing the movement of said deflecting beam with a reed of the loom, and a linkage between said cam drive and said guide means; and wherein said cam drive includes an adjustable dis-engagable coupling element whereby said cam drive can be disengaged to disengage said storage means from operation.

5. An apparatus as set forth in claim 4 wherein said cam drive moves said deflecting beam into a position of greatest deviation from said preset position immediately before a full beat-up and into a position of least deviation from said present position during a full beat-up.

6. An apparatus as set forth in claim 3 wherein said clamping means includes a movably mounted clamping beam disposed between one of a releasing position and a clamping position, said clamping beam being pressed against said bar downstream of said deflecting beam when in said clamping position.

7. An apparatus as set forth in claim 6 wherein said clamping means includes a cam drive for synchronizing the movement of said clamping beam with a reed of the loom, said cam drive including a dis-engagable coupling element whereby said clamping beam can be locked in said releasing position.

9. An apparatus as set forth in claim 7 wherein said storage means further includes a cam drive for synchronizing the movement of said deflecting beam with the reed of the loom, said cam drive including a dis-engagable cam disk element mounted on a common cam shaft with a cam disk of said cam drive of said clamping means.

12. An apparatus as set forth in claim 1 wherein said pile warp release means includes an adjustable release brake, said brake being adjustable as a function of the diameter of wound-on pile warp on a pile warp beam to impart a constant tension to the paid-out pile warp threads, said brake being operable to permit unwinding of the pile warp threads in response to a preset tension in the pile warp threads between said storage means and said pIle warp beam while said clamping means is closed to permit formation of the thread reserve.

13. A method of supplying pile warp threads in a loom for weaving terry cloth wherein the cloth is formed upon beating-up successive weft threads in a shed in a sequence of partial beat-up and full beat-ups, said method comprising the steps of building up a measured reserve of pile warp threads upstream of the shed between successive full beat-ups; clamping the pile warp threads in place at a point between said measured reserve and the shed during building up of the measured reserve; and releasing the measured reserve of pile warp threads during a following full beat-up substantially without tension therein to prevent a backward pull out of the pile warp threads from loops produced thereby.

14. A method as set forth in claim 13 which further comprises the step of withdrawing the pile warp threads during said partial beat-ups while retaining the pile warp threads under tension and while maintaining said reserve.