US3603353A

US3603353A - Method of and apparatus for weaving without knots

Info

Publication number: US3603353A
Application number: US802432A
Authority: US
Inventors: Eduard Glass
Original assignee: ETAG TEXTILWERKE GmbH
Current assignee: ETAG TEXTILWERKE GmbH
Priority date: 1968-02-28
Filing date: 1969-02-26
Publication date: 1971-09-07
Anticipated expiration: 1988-09-07
Also published as: DE1904584A1; DE1904584B2; CH488834A; FR2002769A1; GB1209587A

Abstract

A weaving machine employs apparatus for detecting knots or abnormal thicknesses of weft yarn during the weaving process and apparatus for severing faulty lengths of weft yarn after insertion of the faulty yarn into a shed formed by the warp yarn and apparatus for shutting down operation of the weaving machine and removing the faulty length of weft yarn from the shed prior to setting the machine to repeat the weave and restarting the machine.

Description

United States Patent [72] Inventor Eduard Glm Stalingen-Landwehr, Germany [21 1 Appl, No. 802,432

[22] Filed Feb. 26, 1969 {45] Patented Sept. 7, 1971 [73] Assignee Etag Textilwerke Gmbll [32] Priority Feb. 28, 1968 [33] Switzerland [54] METHOD OF AND APPARATUS FOR WEAVING WlTHOUT KNOTS 15 Claims, 4 Drawing Figs.

[52] US. Cl. 139/370 [51] Int. Cl D03d 51/34 [50] Field of Search 139/370,

371, 303; 66/163; 28/64,70; ZOO/61.144118 [5 6] References Cited UNITED STATES PATENTS 2,329,427 9/1943 Vossen ZOO/61.14

2,841,186 7/1958 Fisher 139/370 2,918,946 12/1959 Pfarrwaller... 139/370 X 3,147,778 9/1964 Reyes 139/303 3,225,794 12/1965 Juillard 139/303 X FOREIGN PATENTS 915,848 7/1954 Germany 66/163 437,163 1 1/1967 Switzerland 139/370 Primary Examiner-James Kee Chi Attorney-Hill, Sherman, Meroni, Gross & Simpson ABSTRACT: A weaving machine 'employs apparatus for detecting knots or abnormal thicknesses of weft yarn during the weaving process and apparatus for severing faulty lengths of weft yam after insertion of the faulty yarn into a shed formed by the warp yarn and apparatus for shutting down operation of the weaving machine and removing the faulty length of weft yarn from the shed prior to setting the machine to repeat the weave and restarting the machine.

PATENTEUSEP 71911 3,603,353

SHEET 2 OF 2 FIG. 3 23 7 IN V EN TOR.

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METHOD OF AND APPARATUS FOR WEAVING WITHOUT KNOTS BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to methods of and apparatus for weaving fabric and is particularly concerned with methods of and apparatus for weaving a knot-free fabric from a continuously fed weft yarn which may include thickness faults such as knots and other thickness abnormalities.

2. Background of the Prior Art During a normal weaving process, any knots or other thickness abnormalities in the weft yarn will cause corresponding irregularities in the fabric being produced by the process. When it is required to manufacture a high-grade fabric, such knots have to be subsequently removed by hand and the process accordingly takes on additional cost in that the hand work must be accomplished by highly skilled workers. Although maximum care may be taken, small weaving faults still remain and reduce the value of a short piece of the fabric.

The manufacture of fabrics containing no faults also increases the cost of the manufacturing process in that an attempt must be made to provide each weft yarn bobbin with a maximum length of yarn without any knots or other abnormalities and, where possible, employ bobbins completely free of knots. Such criteria, however, results in a considerable waste of yarn in the bobbin winding shop in that the yarn must be given special care and inspection during winding and that yarn lengths which are too short must be rejected.

From the foregoing, it is clearly evident that it is necessary to incure additional cost in the manufacturing process for producing knot-free fabric in that additional cost are incured for time, additional labor, and/or considerable waste of yarn. This applies particularly to all normal weaving machines having shuttles which bear bobbins, and also to automatic weaving machines in which the empty weft bobbins are automatically replaced by fresh bobbins and the knots cannot be removed during the insertion of the weft. It is therefore highly desirable, and a primary object of the present invention, to provide a method of and apparatus for weaving knot-free fabric from automatically replaced fresh bobbins of weft yarn which bears knots and other abnormalities.

Another object of the invention is to completely avoid the introduction of knots in weaving machines in which the weft yarn is drawn from stationary bobbins so that the fabric obtained has no knots'while at the same time obviating the foregoing disadvantages of increased cost with respect to time, costof time and wasted weft yarn.

, SUMMARY OF THE INVENTION Briefly, and according to the present invention, a portion of the weft yarn which bears a knot or other abnormality is introduced into the shed formed by the warp yarn and the weaving machine is stopped before the weft is beaten up to compact the fabric. The weft yarn is then cutoff on the empty side and theinserted weft yarn portion bearing the knot or abnormality is removed from the shed.

With the method according to the present invention, the weaving machine can be restarted either immediately or after resetting the machine for repeating the weave, depending upon the fabric weave, whereupon the next weft yarn and all the subsequent weft yarns will be woven in normally in that the weft yarn remains in its delivery position with respect to the feed device on the entry side of the shed and only the normal weft yarn length extending through the fabric is removed.

The arrangement for controlling the provision of a knot-free fabric, according to the present invention, comprises means for detecting an abnormality in the continuously fed weft yarn as the yarn is being delivered to the machine and means for automatically stopping the machine after the required length serted into the shed, but prior to beating up of the weft yarn and before changing of the shed.

In addition, a signal device is advantageously provided to be actuated by the detecting means for alerting the machine minder that an abnormality has been positioned in the shed. The machine minder can then manually remove the inserted length of weft yarn and if necessary restore the wave repeat controls and restart the weaving machine. Further, means are provided whereby the faulty length of yarn is automatically removed in response to a positive indication of an abnormality by the detecting means so that the machine minder is only required to reset and restart the machine.

Inasmuch as it is the normal practice for a machine minder to be responsible for a plurality of weaving machine, the signal device is also provided for alerting the machine minder at a remote location that an abnormality of a weft yarn has been positioned in a shed. The signal device is operated by or in response to the knot detection apparatus.

A particularly advantageous embodiment of the invention includes a control device which receives a control pulse from the knot detection apparatus and operates to stop the weaving machine at a prescribed time delayed sufficiently to permit full insertion of the faulty length of weft yarn, actuate a device for removing the inserted weft yarn and, depending on the type of weave, restores the wave repeat and subsequently restarts the weaving machine. Preferably, however, and not withstanding the provision of such a control system, optical and/or acoustic signal apparatus is provided for signalling the machine minder in response to operation of the knot detecting apparatus so that a machine minder may be alerted to the inoperative condition of the weaving machine even though he may be some distance from the machine.

In order to increase reliability, one or more additional knotdetecting devices may be provided in the region of the weft yarn portion introduced into the shed and be so coupled to the control unit that when a fault occurs the detectingdevices are operable to stop the control unit and the weaving machine on removal of the weft yarn. On withdrawal of the inserted weft yarn the knot may in fact open up or the yarn may break while the remaining weft yarn will stain the fabric and would result in a fault therein. If, however, additional knot detection devices are provided, of which at least one is provided on the entry end between the shears and the fabric edge, on withdrawal of the weft yarn at the outlet end, this particular knot-detecting device would indicate that yarn still remains in the fabric in the event that the knot opens or that the yarn breaks on withdrawal. By employing such device or devices in conjunction with the control unit, the alarm signal would remain effective so that the machine minder is again alerted and can clear the fault.

A normal weaving knot has the thickness of approximately four courses of yarn at its thickest point. The knot-detecting apparatus employed may therefore include photoelectric dc tecting apparatus which responds to thick zones of yarn, however, other types of knot-detecting apparatus may be employed. In the particular example of the invention illustrated herein the knot-detecting apparatus comprises a pivotal fork having a slot corresponding to the thickness of the weft yarn. The weft yarn is disposed to run through the slot during delivery thereof to the weaving machine. The appearance of a knot or other thick zone in the yarn pivots the fork out of its normal resting positions whereby the fork closes an electrical contact or a mechanical device for stopping the machine or signalling a control unit for stopping the machine and energizing an alarm apparatus. It is particularly advantageous for the fork to be disposed interchangeably on a pivoting arm so that the fork can be adapted to any desired thickness of weft yarn.

Apparatus for removing the faulty inserted weft yarn may, for example, employ a small rotating rough roller which can be moved into contact with the weft yarn at the opposite end of the shed and which mechanically or electrostatically engages and coils up the weft yarn. Alternatively, it is possible to employ a lever with a hook system which draws the weft yarn from the shed in the form of a loop. The particular arrangement illustrated herein employs a suction nozzle disposed at the exit end of the shed which is connected to a source of vacuum and which is brought into fluid communication with the source of vacuum by means of a valve which is operable in response to the detection of a faulty length of weft yarn.

When an automatically operating control unit is provided, the removal of the portion of the weft yarn bearing the knot can be carried out in a few seconds from the time the knot is detected until the machine is restarted so that the weaving machine efficiency with the method according to the present invention is substantially the same as if the same fabric were being woven while permitting the inclusion of knots. However, the total efficiency to produce knot-free fabric is considerably increased both in production time and in cost when compared to techniques heretofore employed to clear knots from a woven fabric or to prepare bobbins for weaving knot-free fabric. Even when no control unit is employed and the weaving machine is completely manually attended by a machine minder who withdraws the inserted weftyam, resets the heddles for repeating the weave where necessary and restarts the machine, the weaving process is substantially more economical than that demonstrated by prior methods. In addition, there is a significant improvement in the quality of the fabric manufactured. Further, there are considerable savings in weft yarn since only a single relatively small length of weft is necessarily sacrificed because of the knot, and not half the bobbin length as was conventional on the average.

BRIEF DESCRIPTION OF THE DRAWINGS "The foregoing and other objects, features and advantages of the"inve'ntion, its organization, construction and operation, will "be best understood by referring to the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a pictorially illustrated diagrammatic representation of apparatus for weaving knot-free fabric in accordance with the principles of the invention; and

FIGS. 2, 3 and '4 illustrate one particular form of knot-detecting apparatus which may be employed in practicing the invention and which is also illustrated as a portion of the apparatus of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, a pair of stationary weft yarn bobbins l and 2 are illustrated for supplying a continuous strand of weft yarn 4 to a weaving machine 11 through a yarn guide 5, a yarn brake 6, knot-detecting apparatus 7, feed device and yarn shears 8. The feed device 10 is a reciprocating gripping device for use with, in this example, a gripper shuttle type of loom, which feed device 10 is operable in the directions indicated by the double headed arrow.

The yarn shears 8 are disposed between the feed device 10 and the weaving machine 11 and are operable after each weft yarn insertion to sever the inserted portion 4 of the web yarn from the continuous weft yarn strand 4. The open shed of the warp yarns is indicated on the weaving machine 11 by the two cloned lines 12 which symbolize the cross section through the warp yarns. A suction nozzle 13 is provided beneath the righthand end of the portion 4' that has already been inserted into the shed l2, i.e. on the exit side of the shed, and is connected to a vacuum source via a remotely controlled valve 17. In the particular example illustrated, the vacuum source takes the form of a collector unit 14 with a filter strainer and a suction fan 15 connected in fluid communication therewith. An existing yarn breakage suction system or the like may be employed as the vacuum source if desired.

In FIG. 1 it has been assumed that a knot 9 has actuated the knot detector 7 and then, born by the portion 4' of the weft yarn, has entered the open shed of the warp yarns 12. The particular knot detector illustrated includes an upperwardly extending fixed arm 26 having a yarn guide nozzle or aperture 18 therein for passing the continuous strand of weft yarn 4 and a vertical base plate 23 supporting the extending arm 26. The actual stop motion element of the knot detector is illustrated in the form of an elongate member having a forked end 7, the slot of the fork being of particular dimensions with respect to the weft yarn being woven. The elongate element carrying the forked end 7 is secured to an arm 19 by means of a locking screw 27, the arm 19 being pivotally carried by base plate 23 by a pivot 20. In the normal vertical position, the pivoting arm 19 is subject to the action of a restoring spring 25 connected between the elongate fork member 7 and the base plate 23 and thus bears against a setscrew 24 which is provided with a locknut. At the end of the arm 19 which is remote from the elongate fork member 7 is an adjustable contact screw 21, also provided with a locknut, for actuating an electrical contact device 22 which is carried by and insulated from the base plate 23.

As a knot or other abnormality in the weft yarn passes the knot detector, the edges of the slot of fork 7 form an interference relationship therewith and the fork 7 and pivotal member 19 are forced out of the normal vertical position into a pivoted position by the knot 9, as illustrated in FIGS. 2 and 3, until which time the knot 9 has passed and disengaged from the fork. This momentary swing of pivoting arm 19 causes a momentary operation of contact device 22 to generate an electrical signal for stopping the machine 11 and energizing the alarm apparatus 28. The electrical signal may perform these functions through the medium of a control circuit 16 which is illustrated as being mounted on the machine II and which would include the necessary apparatus for delaying the inactivation of the machine a sufficient time to permit complete insertion of the faulty portion of the weft yarn into the shed. Such time delay, however, would not extend to permit beating up the faulty yarn to compact the fabric. This delay interval may also be effected, or partially effected, by the adjustment of

setscrews

21 and 24 to provide adjustment of a permissible swing of the pivoting elements 7, l9 and 211 about pivot point 20.

Inasmuch as the elongate fork element 7 is releasably secured to the arm 19 by means of the screw 27, the arm H9 can be adapted to any particular thickness of yarn desired, as hereinbefore mentioned.

With particular reference to FIG. 1, the control unit 16 may be constructed to cause energization of the alarm device 28, in this case a lamp, and to also place the weaving machine in an off condition. This action may be provided by a time control relay which is effective at a time when the weft yarn portion 4 bearing the knot 9 has completely entered the shed, but has not yet been beaten up. After the weaving machine has been stopped, the control unit 16 is constructed to open the valve 17 for a short period whereby the nozzle 13 sucks in the faulty weft yarn end and thus sucks the weft yarn portion 4' including the knot 9 out of the shed 12. It has been assumed here that the faulty portion of the weft yarn has already beers severed by the shears 8 as is customary for the type of machine illustrated; however, if the system is employed in a gripper type of loom in which the shears 8'have not yet been actuated at the time when the loom has been stopped by the control unit 16, provision must be made for the control unit to actuate the shears 8, the incoming weft yam being picked up and stopped by the feed device 10. Once the weft yarn has beers removed from the shed 12, the control unit 16 is constructed to restart the weaving machine by means of the known starting system (not shown) whereupon the control unit is reset and the alarm device 28 is turned off. The weaving machine will then continue to operate in the proper manner.

For installations wherein a control unit of the type described is not employed, the weaving machine may be stopped in the same manner by the knot-detecting apparatus and the alarm device 28 or other signals may be switched on, This alternative approach is illustrated in FIG. 1 by the switch circuit 30 which receives inputs A and B from the detecting apparatus and is symbolically connectable to the alarm zip paratus Ml by switch 31 and to machine llll by switch 32. The switching circuit may comprise any suitable structure, for example relays, for effecting the desired control of the machine Ill and the alarm device 28. The machine minder may then manually withdraw the inserted faulty weft yarn, set the wave repeat where required and restart the machine. These operations require only a small amount of time, but inasmuch as the weaving machine minder is normally responsible for a number of looms, a weaving machine may be stationary for a relatively long period resulting in lost time in the weaving process. For this reason, it is preferable to provide an automatically operating control unit.

The control unit may be constructed for a simple control cycle and in a well-known manner it may comprise electrical contactor, a time relay and possible a servomotor. As shown in FIG. 1, the control unit 16 may be disposed on the loom itself, or it may be placed at some other suitable location, e.g. in or on the creel.

Continuing with reference to FIG. 1, there may also be provided a plurality of knot-detecting devices, such as 7a and 7b, positioned on the delivery and exit sides of the shed. As previously set forth, on withdrawal of the inserted weft yarn the knot may in fact open or the yarn may break leaving undesired weft yarn in the fabric which would result in a fault. If, however, one or more knot detectors are provided, at least one being provided at the entry and between the shears and the fabric edge, a yarn stop signal would be generated to account for an additional amount immediately following a knot which has already triggered shutdown of the machine. At the exit end of a shed, a knot detection device may be employed to indicate complete withdrawal of the weft yarn so that a broken segment of yarn will not remain in the fabric. The control unit 16 would accordingly be provided with additional inputs C, D. E and F for controlling the operation thereof and may include circuit apparatus which would not permit resetting of the control unit and alarm device until the shed has been completely cleared of faulty weft yarn.

Although minor modifications might be suggested by those versed inthe art, it should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.

What I claim as my invention is:

1. In the method of weaving fabrics from a supply of weft yam on a machine which forms sheds and which method includes the steps of delivering weft yarn to the machine, inserting a length of weft yarn fully into the shed, severing the length of yarn on the delivery side of the shed and beating the inserted length of yarn to compact the fabric, the improvement for providing fabric which is free of thickness faults in the weft yarn comprising the steps of detecting thickness faults in the weft yarn during delivery thereof to the machine, deactivating the machine only after complete insertion of and prior to beat ing of a fault-bearing length of weft yarn within a shed in response to the detection of the fault, and withdrawing the fault-bearing length of weft yarn from the shed.

2. The method according to claim ll, wherein the step of withdrawing the fault-bearing length is further defined as applying a vacuum to the fault-bearing length for removing it from the shed.

3. The method according to claim ll, wherein the step of detecting thickness faults is further defined as comparing the thickness of yarn being delivered to the machine with a predetermined thickness.

4. The method according to claim 3, wherein said step of detecting thickness faults is further defined as generating fault-indicating signals upon detection of a yarn thickness greater than the predetermined yarn thickness.

5. A method of weaving fault-free fabric from a supply of warp yarn and a supply of weft yarn in the form of an endless fault-bearing strand, comprising the steps of cyclically forming sheds of warp yarn for receiving the weft cyzlically inserting the leading portion of the endless strand of weft yarn fully into a formed shed,

cyclically cutting the inserted portion from the endless strand to establish a new leading portion,

cyclically beating the inserted portion against previously inserted portions to compact the weave,

sensing the thickness of the leading portion prior to insertion into a shed and interrupting the cycle only after complete insertion in response to the detection of a yarn thickness fault in the inserted portion, and

removing the inserted fault-bearing portion from the shed.

6. A machine for weaving fabric from a supply of weft yarn bearing thickness faults therein from a supply of warp yarn comprising means repeatedly forming sheds from said warp yarn, means for inserting a predetermined length of weft yarn including faults therein into a formed shed, means for cutting the predetermined length of weft yarn from the supply of weft yarn, fault-detecting means disposed between the supply of weft yarn and the shed forming means for sensing thickness faults in the weft yarn, said fault-detecting means including means for generating fault indicative signals, means for controlling on and off conditions of the machine coupled to said detecting means and operable in response to fault-indicative signals to place the machine in an off condition at the moment when a fault-bearing length of weft yarn is completely introduced into the shed.

7. The weaving machine according to claim 6 comprising means coupled to said fault-detecting means and operable in response to fault-indicative signals to withdraw fault-bearing lengths of weft yarn from the formed sheds.

8. The weaving machine according to claim 7, wherein said means for withdrawing a fault-bearing length of yarn from a shed comprises a source of vacuum, a nozzle connected to said source of vacuum and disposed adjacent the shed area, and a control valve interposed between said source of vacuum and said nozzle for controlling the application of a vacuum to a fault-bearing length of weft yarn.

9. The weaving machine according to claim 6, further comprising alarm means coupled to said detecting means and operable to provide an alarm signal upon detection of a fault.

It). The weaving machine according to claim 7, wherein said fault-detecting means comprises means for detecting the withdrawal of a faulty length of yarn from a shed.

11. The weaving machine according to claim 10, wherein said means for detecting withdrawal of a faulty length of yarn from a shed comprises a plurality of detecting means disposed adjacent each end of a formed shed.

112. The weaving machine according to claim 6, wherein said fault-detecting means comprises a fixed base member, electrical contacts carried by said base and connected to said condition controlling means, a movable member pivotally mounted to said base member including means forming a fork at one end thereof loosely embracing said weft yarn and dimensioned to pass only yarn of a thickness which is less than a predetermined value, said movable member pivoted by yarn thickness greater than the predetermined value to operate said electrical contacts.

13. The weaving machine according to claim 12, wherein said detection means comprises spring means connected between said fixed base member and said movable member to bias said movable member toward said fixed member.

14. The weaving machine according to claim 12, wherein said detection means comprises means secured to said movable member for contacting and operating said electrical contacts and means for adjusting the degree of motion required of said movable member to operate said electrical contacts.

15. The weaving machine according to claim 12 wherein said movable member includes means for releasably securing thereto said means forming said fork so that the detecting means may be adapted to operate with respect to various yarn thicknesses.

Claims

1. In the method of weaving fabrics from a supply of weft yarn on a machine which forms sheds and which method includes the steps of delivering weft yarn to the machine, inserting a length of weft yarn fully into the shed, severing the length of yarn on the delivery side of the shed and beating the inserted length of yarn to compact the fabric, the improvement for providing fabric which is free of thickness faults in the weft yarn comprising the steps of detecting thickness faults in the weft yarn during delivery thereof to the machine, deactivating the machine only after complete insertion of and prior to beating of a faultbearing length of weft yarn within a shed in response to the detection of the fault, and withdrawing the fault-bearing length of weft yarn from the shed.

2. The method according to claim 1, wherein the step of withdrawing the fault-bearing length is further defined as applying a vacuum to the fault-bearing length for removing it from the shed.

3. The method according to claim 1, wherein the step of detecting thickness faults is further defined as comparing the thickness of yarn being delivered to the machine with a predetermined thickness.

5. A method of weaving fault-free fabric from a supply of warp yarn and a supply of weft yarn in the form of an endless fault-bearing strand, comprising the steps of cyclically forming sheds of warp yarn for receiving the weft yarn, cyclically inserting the leading portion of the endless strand of weft yarn fully into a formed shed, cyclically cutting the inserted portion from the endless strand to establish a new leading portion, cyclically beating the inserted portion against previously inserted portions to compact the weave, sensing the thickness of the leading portion prior to insertion into a shed and interrupting the cycle only after complete insertion in response to the detection of a yarn thickness fault in the inserted portion, and removing the inserted fault-bearing portion from the shed.

10. The weaving machine according to claim 7, wherein said fault-detecting means comprises means for detecting the withdrawal of a faulty length of yarn from a shed.

12. The weaving machine according to claim 6, wherein said fault-detecting means comprises a fixed base member, electrical contacts carried by said base and connected to said condition controlling means, a movable member pivotally mounted to said base member including means forming a fork at one end thereof loosely embracing said weft yarn and dimensioned to pass only yarn of a thickness which is less than a predetermined value, said movable member pivoted by yarn thickness greater than the predetermined value to operate said electrical contacts.