US2930411A - Fault detection apparatus for weaving - Google Patents

Description

March 1960' J. R. CALHOUN ET Al. 2,930,411

FAULT DETECTION APPARATUS FOR wmvmc 2 Sheets-Sheet 1 Filed Hay 5, 1958 INVENTORS JAMES R. CALHOUN WILLIAM L. SHIRLEY 8422mm MM ATTORNEYS March 29, 1960 J. R. CALHOUN ETAL 2,930,411

FAULT DETECTION APPARATUS FOR WEAVING Filed May 5, 1958 2 Sheets-Sheet 2' INVENTORS JAMES R; CALHOUN WILLIAM L. SHIRLEY ATTORNEYS" United States Patent 2,930,411 FAULT DETECTION APPARATUS FOR WEAVING James R. Calhoun, Montgomery, and William L. Shirley,

Union Springs, Ala., assignors, by mesne assignments, to Appleton Wire Works Corp, Appleton, Wis, a cor poration of Wisconsin Application May 5, 1958, Serial No. 733,205

13 Claims. (Cl. 139-352) This invention relates to looms for wire weaving and more specifically resides in fault detection apparatus that promptly detects imperfections as they occur at the beat line, which apparatus comprises an elongated electrically conductive tactile bar that parallels and spans across the beat line to rest upon threads at both sides of the beat line to bridge the same, whereby faults in the cloth that protrude from the cloth surface will be contacted by the bridging tactile bar to complete an electrical circuit and thereby indicate the presence of such fault.

In Fourdrinier wires, slight defects and faults which protrude from the woven surface cannot be tolerated. These wires are endless belts of fine mesh upon which pulp is laid down to form the initial paper web, and slight imperfections in the wire, such as raised knuckles or creepers, transfer an impression to the web that may necessitate a rejection of the finished paper. Consequently, it is imperative that the wires be free of such imperfections. Further, Fourdrinier wires are'operated at high speeds and pass over rolls of small diameter, such that imperfections in the wires will result in abnormal wear and rapidly lead to premature failures.

The detection of faults, or imperfections, in Fourdrinier wires has heretofore been a most difficult problem.- These wires may have a mesh exceeding sixty wires per lineal inch, while the width of the wire may be greater than twenty feet. Consequently, visual detection of defects requires a high degree of observance, and it is manifest that a loom operator, who .is busied with the manipulation of the entire loom, cannot adequately inspect the cloth as it is being woven. As a result, when such defects do escape prompt detection it may become necessary to sever the screen transversely for the purpose of physically cutting out an imperfection. This procedure necessitates the making of an additional seam which is both expensive and laborious.

Defects of the type which frequently occur during the weaving process, and which may be detected by the apparatus of this invention, are caused by the development of small loops at the forming edge or beat line of the cloth. Such loops appearing in the warp threads are commonly termed creepers, while similar loops appearing;in the weft threads are termed slacks. When these faults are detected immediately upon their occurrence the loom may be stopped and the imperfect threads replaced or straightened with a minimum of difiiculty.

Since it is desirable to detect imperfections at or very near the beat line, the detecting apparatus must necessarily'be placed proximate to the beat line during a testing period. However, as the lay advances to beat up the weft threads, the detecting apparatus must beremoved from-the path of the lay. Heretofore it has been suggested thata fault detecting member could have a movement across the surface of the woven cloth, the movement beingaccornplished by a mechanical linkage associated 'with the lay. The detecting member. in this.

priohsh'gg'estion consists of an electrically conductive'rod supported above the cloth by a large insulating block bearing directly upon the cloth at all times, as it slides back and forth across the cloth. An inherent weakness of such structure is that the insulating block is subjected to incessant sliding friction resulting in rapid erosion which destroys the close dimensional tolerances which must be maintained.

In the present invention a novel bridging ofthe beat line is made by a tactile barafter each beat of the lay. Movement of the tactile bar toward and away from the bridging position is accomplished by a movement having a directional component normal to the cloth, and surface wear is accordingly minimized. It is essential in a fault detection apparatus that the detecting member be spaced in precisely the same relation to the cloth after each beat of the lay. Also, since the spacing between the detecting member and the cloth must be kept within a small dimensional tolerance wear of parts will defeat a practical, working apparatus. The present invention reduces wear to a minimum, and thus makes it possible to ensure the detection of faults as weaving is continuously carried out.

It is an object of this invention to provide a fault detection apparatus for a loom adapted to detect imperfections appearing at or near the beat line of the woven cloth.

It is another object of this invention to provide a fault detection apparatus for a loom which is adapted to halt the weaving process when an imperfection occurs in marginal areas adjacent ot the beat line of the woven cloth.

It is another object of this invention to minimize sliding friction between a detection member of apparatus of the type herein described and a wire cloth to insure performance over a long period of operation.

It is another object of the invention to provide a fault detection apparatus having a detection member adapted for a movement into and out of test position that is transverse to the cloth.

It is another object of this invention to test for imperfections at the beat line without interruption of the weaving process.

. It. is another object of this invention to detect faults in a wire cloth to both sides of the beat line, to thereby enhance the operation of the apparatus.

The foregoing and other objects and advantages of this invention will appear from the following description. In

Fig. 3 is a partial plan view of the apparatus with the lay retracted as in Fig. 1,

Fig. 4 is an enlarged side view in elevation and in section of the detection portion of the apparatus, which portion includes a tactile bar that is shown making contact with one form of imperfection,

Fig. 5 is an enlarged side view in elevation and in section of the detecting portion, with the tactile bar in,

contact with another form of imperfection,

Fig. 6 is a fragmentary plan view showing a portion'of the apparatus, and I .Fig. 7 is a schematicwiring diagram of a loom control circuit incorporating apparatus of the invention.

Referring now to the drawings, a portion of a woven;

' wire cloth lis shown which comprises warp threads 2,

and weft threads 3. The warp threads 2 pass through heddles 4 and 5 which are vertically offset with respect to one another, in usual fashion, to cause the warp threads 2 to form a shed 6 having an apex defined by a beat line 7. The warp threads 2 also pass through the reeds 8 of a reciprocable lay 9, which reciprocates between a retracted position as shown in Fig. 1 and a beat position shown in Fig. 2. In the position of Fig. 2 the reeds 8 are at the beat line 7, which is the forming edge of the cloth at which successive weft threads 3 are forced into meshing conformity with the warp threads 2. It is to be understood that only fragmentary portions of a loom are shown in the drawings, these portions being sufficient to set the environment for the invention.

In Figs. l-S there is shown a flat base plate 10 immediately above the woven cloth 1 in a position forward of the beat line 7. The rear portion 11 of the base plate 10 has one margin of a flexible sheetlike hinge 12 adhered to its upper surface. The opposite margin of hinge 12 is clamped between the upper surface of a tactile bar 13 and an angle brace 15, by means of a set of through bolts 16. The hinge 12 permits a swinging descent of the bar 13 and brace 15 into the position of Figs. 1, 4 and 5, and a swinging ascent into the position of Fig. 2. This pivotal motion is achieved about an axis parallel with the beat line 7, and provides for retraction of the tactile bar 13 from a position of test that bridges the beat line 7. A strip of leather has been found to be a desirable material for the hinge 12, because of its inherent strength and resiliency.

The tactile bar 13 consists of an electrically conductive material such as soft iron, aluminum or copper and extends along the entire length of the beat line 7, as is shown in Fig. 3. A plurality of base plates 10, with accompanying hinges 12, retain the bar 13 in place, and in Fig. 3 one of the plates 10 is shown as being representative of the plurality. As is most clearly shown in Figs. 4 and 5 thin insulation strips 14 are disposed along the margins of the underside of the bar 13 to mask these areas while leaving the center portion of the bar 13 exposed to form a detection area 13'. Any suitable insulating sheet material may be used for the strips 14, but it has been found desirable to employ a wear-resistant pressure-sensitive insulating tape such as is commercially known under the mark Teflon. Strips of a thickness in the range of from three-thousandths of an inch to tenthousandths of an inch have been found to be satisfactory, however, the particular thickness selected is dependent upon the degree of sensitivity of the detection apparatus, as will hereinafter be discussed.

A lifting lever 17 overhangs each base plate 10, and each lever 17 is inclined with an elevated after end which rests in sliding contact upon a lay cap 18 of the lay 9. A pair of guide pins 18 extend upwardly from the lay cap 18 for each lever 17, to retain the levers 17 in proper alignment. The lower forward end of each lever 17 is pivotally secured near the forward position of its associated base plate 10 through the medium of a formed bracket 26. The pivotal connection consists of an armate vertically extending pin 19 secured at its lower end to the bracket 26 and receive by an opening 20 in the lifting lever 17, together with a socket 21 that is a curved integral extension of the bracket 26. The lower end of the lever 17 is received by the socket 21, so that it may pivot therein, and the pin 19 holds the lever 17 captive in engaged relation with the socket 21.

The bracket 26 serves to secure the base plate 10 to a flat rod 24 fastened at its ends to side frames 25, as shown in Fig. 3. The bracket 26 closely conforms to the top and sides of the rod 24,'and is provided with a horizontal, flat rearward extension 27 which is secured to the base plate 10 by bolts and wing nut assemblies 28. The bracket extension 27 is provided with extended slots 29 to receive the assemblies 28, such that the position of the base plate 10 may be varied with respect to the bracket 26. In this manner the position of the tactile bar 13 may set with respect to the beat line 7.

The tactile bar 13 is connected to each of the lifting levers 17 by means of a flexible connecting strap 22. Each strap 22 is secured at one end to the bar 13 by being clamped between the bar 13 and the associated angle brace 15, similarly as and together with each hinge 12. The opposite end of each strap 22 is secured to the associated lifting lever 17 by means of a clamp and bolt assembly 23. Each assembly 23 may be loosened, and then slid along its lever 17 to adjust the position at which the strap 22 and lever 17 are joined.

There is also provided an additional flexible coupling between each lifting lever 17 and its associated base 10, which comprises a strand 30 of predetermined length secured at its upper end to the lifting lever 17 at a point intermediate the pin 19 and the clamp 23, and secured at the lower end to the base plate 10 at a point to the rear of the bracket 26. The purpose of this additional coupling will be discussed hereinafter.

Illustrations of faults that may occur at the vicinity of the beat line 7, as weaving is carried out, appear in Figs. 4 and 5. In Fig. 4 there is shown a loop 31 in the form of a creeper that is raised above the level of the woven cloth and in contacting position with the detection area 13' of the tactile bar 13. In Fig. 5 there is shown a raised loop 32 in the form of a slack caused by an improper shot or slack weft wire, which loop is also shown in contacting position with the detection area 13.

In Fig. 7 there is schematically illustrated an electrical control circuit which may be used in conjunction with the conductive tactile bar 13, to provide a means for stopping loom operation upon detection of a fault. The circuit is shown to include a connection of the tactile bar 13 into a supervisory loom governing circuit 33. The circuit 33 is joined to power lines 34 and may take the form of a known governing circuit, and as a specific example the circuit 33 may be patterned after that shown in US. Letters Patent No. 2,810,402, dated October 22, 1957. The circuit 33 is shown to include a ground connection as well as the woven cloth 1, such that contact of the cloth 1 with the bar 13 may cause the circuit 33 to function. A drive motor 35 is shown which drives the loom through an electrical clutch 36, the operation of which is controlled by the circuit 33, such that detection of a fault will cause the circuit 33 to disconnect the clutch, and thus halt the weaving operation.

The operation of the apparatus of the invention may be described in conjunction with the operation of the loom, only parts of which have been shown for reasons heretofore given. When the heddles 4 and 5 are olfset vertically with respect to one another to form the shed 6 between the separated warp threads 2, a weft thread 3 is inserted transversely between the warp threads 2 by a shuttle, not shown. The lay 9 is then advanced toward the beat line 7 to cause the reeds S to beat up the weft thread 3. As the lay 9 moves toward the beat line 7 the incline of the lifting levers 17 is increased, to cause the flexible connecting straps 22 to first become tensioned and then to raise the tactile bar 13 away from the beat line 7. Thus, the bar 13 is moved out of the path of the advancing lay 9 by a pivotal motion into the position shown in Fig. 2. After the beat, the lay 9 is returned to its initial position shown in Fig. 1, and as the lay 9 moves rearwardly the lifting levers 17 descend to allow the tactile bar 13 to fall under the force of gravity and aided by the resiliency of the hinge 12.

The bar 13 will come to rest in a test position upon the cloth 1, as shown in Figs. 1, 4 and 5. It may be seen from the drawings that when the bar 13 is in test position the insulating strips 14 are disposed on opposite sides of the beat line 7 whereby the exposed detection area 13 bridges the beat line 7. Also, the strips 14 bear upon the threads'so that the area 13' is spaced slightly above the beat line 7 and the adjacent areas to each side;

again;

The vertical distance between the threadsand the; detection area 13 is determined by the thickness of the insulation strips 14 and the angle of the warp threads 2 forming the top of the shed 6. The sensitivity of the apparatus, as measured by the minimum altitude of detectable imperfection, may be controlled by the use of strips 14 of different thickness. It has been found that thicknesses of three to ten thousandths'of an inch are satis-' factory for usual purposes. L a

When an imperfection develops, such as a creeper 31 or a slack 32, contact is made between the raised thread and the detection area 13'. With the bar 13 connected in a circuit, as shown in Fig. 7, the electric clutch 36 is disengaged to disconnect the loom from its driving source 35. While various loom disabling circuits may be used in conjunction with apparatus of the invention, it has been found preferable to employ means of the type described wherein the current flowing through threads is of a very small value so as to reduce the possibility of electrical arc erosion at the point of contact between the imperfection and the detection area 13'.

In some instances the rotation of the bar 13 upwardly and away from the path of the lay 9 may cause'the weight of the bar 13 to bear upon the base 10 and hence upon the cloth 1 with sufficient downward pressure to disturb the warp ends near the base 10 at the time of heat to produce slight scallops or blisters which are injurious to the cloth. product. This condition is eliminated by the use of strand 30 connected between the base plate 10 and the lifting lever 17. The strand 30 is of a suitable length such that when the lifting lever 17 is rotated to its maximum forward position the strand 30 will be in tension to lift the rear portions of the base plate 10 a slight distance above the surface of the woven cloth 1. The forward end of the plate 10 may be retained in a position slightly elevated from the cloth surface by disposing the rod 24 at a suflicient height. Then, with the plate 10 fully elevated from the cloth 1 the possibility of resulting scallops and blisters is eliminated.

The imperfections in the woven cloth which this invention will detect are not solely limited to those hereinbefore described, but may include numerous other faults such as, for example, might be produced by the incorporation of foreign materials in the mesh of the cloth. It is desirable to weave in a manner that imperfections will appear at the upperside of the cloth, in order that satisfactory detection of faults may be accomplished by a single tactile bar 13 positioned on the upperside of the cloth. Various known settings of the loom may accomplish this result such as the direction of movement and the angle of the reeds 8, as they approach beat position, together with the inclination of the warp threads 2. These factors may also tend to cause the first weft 3 at the beat line 7 to be at a slightly higher level than the adjacent woven cloth.

It is understood that this invention may be embodied in forms other than that shown and described, and that changes and modifications may be made in the various elements comprising the apparatus described without departing from the spirit or scope of the invention, which is limited only by the appended claims.

We claim:

1. In a fault detection apparatus for a wire weaving loom having a lay reciprocatively movable forward toward and rearward from a beat line, the combination of a tactile bar extending parallel of the beat line which has a test position immediately above the beat line, said tactile bar having insulating means at its opposite edges that are interposed between the bar and wire of the loom when the bar is in test position to space the bar from the wire, a mounting for said tactile bar that allows the bar to be raised from the test position and returned thereto, and an operating linkage for said tactile bar adapted to move the bar upwardly and downwardly in synchronism with lay movement.

. 2. In a fault detection apparatus fora wire weaving.

loom having a lay and mechanism for reciprocally moving said lay forward toward and from'a beat 'line; the

combination of a pivotally mounted tactile bar extending parallel to the beat line and having a test position immediately above the vicinity of the beat line, said bar having a downwardly facingtest surface which is flanked at its either side by insulators that extend beneath the plane of the test surface; and an operating linkage coop-' eratively joining said tactile bar and said mechanism to pivot the barforwardly and rearwardly in synchronism with lay movement.

' 3. In a fault detection apparatus for a wire weaving loom, having a lay reciprocatively movable forward toward and from a beat line; the combination of a pivot 5. In a fault detection apparatus for a loom for weav-.

ing warp and weft wires into cloth and which has a lay reciprocatively movable forward toward and from a beat line; the combination of a pivotally mounted tactile bar extending parallel to the beat line and having a test position immediately above the vicinity of the beat line, said bar having a downwardly facing test surface which is flanked at its either side by insulators that extend beneath the plane of the test surface for contact with the warp wires at one side of the beat line and with the cloth at the other side of the beat line; and an operating linkage for said tactile bar adapted to pivot the bar forwardly and rearwardly in synchronism with lay movement.

6. In a fault detection apparatus for a wire weaving loom having a lay reciprocatively movable forward toward and from a beat line; the combination comprising a base positioned forwardly of the beat line; a tactile bar extending parallel to the beat line which has a test position immediately above the vicinity of the beat line; a pivotal connection between said bar and said base and allowing said bar to rotate from the position of test upwardly and forwardly to a position forward of the beat line, and an operating linkage cooperatively joining said tactile bar and the lay to pivot the bar forwardly and rearwardly in synchronism with lay movement.

7. An apparatus as described in claim 6 in which said loom includes side frames and a rod positioned forwardly of said heat line and extending across said loom for connection with said side frames, said base being adjustably secured to said rod to permit forward and rearward adjustment of said base with respect to said rod.

8. In a fault detection apparatus for a wire weaving loom having a lay reciprocatively movable forward toward and from a beat line; the combination comprising a base positioned forwardly of the beat line; a tactile bar extending parallel to the beat line which has a test position immediately above the vicinity of the beat line; a hinge operatively connecting said bar and said base and allowing said bar to rotate from the test position upwardly and forwardly to a position forward of the beat line; a lifting lever extending from a pivotal connection with said base upwardly and rearwardly to slidably contact said lay, whereby said lever may rotate about said pivoted connection synchronously with lay movement; and connections joining said lever and said tactile bar to rotate the bar forwardly and rearwardly about said hinge in re sponse to rotation of said lever.

9. An apparatus as described intclaim 8 wherein said hinge comprises a stri of pliablesheetdike material bridg ing said base and said tactile bar and secured thereto.

10. An apparatus as described in claim 8 having a connection operatively joining said lifting lever and said base to raise said base as said lever is rotated forwardly.

11. In a fault detection apparatus for a loom that weaves warp and weft wires into cloth and which has a lay reciprocatively movable forward toward and from a beat line; the combination comprising a base positioned forwardly of the beat line; a tactile bar extending parallel to the beat line and having a test position immediately above the vicinity of the beat line, said bar having a downwardly facing test surface which is flanked at its either side by insulators that extend beneath the plane of the test surface for contact 'with the warp wires at one Side of the beat line and with the cloth at the other side ofthe beat line; a hinged connection between said bar and said base that allows the bar to rotate from the test position upwardly and forwardly to a' position forward of the beat line; a lifting lever extending from a pivotal connection with said base upwardly and rearwardly to slidably contact said lay whereby said lever may rotate about said pivoted connection synchronously with lay movement; and connections joining said lever and said tactile bar to rotate the bar forwardly and rearwardly about said hinge in response to rotationof said lever.

12. In a fault detection apparatus for a loom that weaves warp and weft wires into cloth and which has a lay reciprocatively movable forward toward and from a beat line; the combination of a pivotally mounted tactile bar extending parallel to the beat line and having a downwardly facing test surface which is flanked at its either side by insulators that extend beneath the plane of the test surface for contact with the warp wires at one side of the beat line and with the cloth at the other side of the beat line, with the test surface bridging across the beat line; and an operating linkage cooperatively joining said tactile bar and the lay to pivot the bar forwardly and rearwardly in synchronism with lay movement.

13. In a fault detection apparatus for a loom that weaves warp and weft wires into cloth and which has a lay reciprocatively movable forward toward and from a beat line; the combination of a pivotally mounted tactile bar extending parallel to the beat line and having a downwardly facing electrically conductive test surface which is flanked at its either side by insulators that extend beneath the plane of the test surface for contact with the warp wires at one side of the beat line and with the cloth at the other side of the beat line, with the test surface bridging across the beat line; an operating linkage cooperatively joining said tactile bar and the lay to pivot the bar forwardly and rearwardly in synchronism with lay movement; an electrical loom control circuit and electrical connections joining said control circuit between said test surface and said cloth whereby contact between said cloth and said surface is adapted to energize the control circuit.

References Cited in the file of this patent UNITED STATES PATENTS 2,639,735 Fisher -t May 26, 1953

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