US3192595A - Weft straightener - Google Patents

Description

July 6, 1965 H. MORTON ETAL WEFT STRAIGHTENER 3 Sheets-Sheet 1 Filed March 2-, 1962 MR Mum IWM m fi m/4 u a July 1965 H. MORTON ETAL 3,192,595

WEFT STRAIGHTENER 3 Sheets-Sheet 2 Filed March 2 1962 July 6, 1965 H. MORTON ETAL WEFT STRAIGHTENER 3 Sheets-Sheet 3 Filed March 2 1962 IN V EN TOR-S Hunnmcy flfamw Fen k v/ Le-hwaz 9 M #M United States Patent 3,192,595 WEFT STRARGH'EENER Humphrey Morton, Rte. 4, Box 450, Danville, Va., and Frank W. Leitner, 1218 Canterbury Road, Charlotte, N.C.

Filed Mar. 2, 1962, Ser. No. 177,127 3 Claims. (Cl. 26-515) This application is a continuation-in-part of our copending application, Serial No. 77,568; filed on December 22, 1960; for Weft Straightener and Alignment Detector.

This invention relates to a weft straightening device and specifically to a device for correcting misaligned weft in a traveling strip of woven fabric whether it be a skew, a bow, or a combination of skew and bow.

In the art of weft sensing and correcting, there have been many ingenious mechanisms devised which will detect and correct both weft and bow, and some to additionally correct a bow-skew condition. However, these prior art mechanisms respond to irregular conditions which are in no way related to the condition of the weft alignment.

The mechanical correction units to which this invention relates are straight rollers which can be canted across the direction of cloth or fabric travel to correct skew, and bowed rollers which have a middle section capable of extending into the planes of the fabric to increase its path of travel to correct bow. A skew-bow condition is correctable by using a combination of such rollers.

The invention provides a weft straightening framework wherein a plurality of bow rollers and a plurality of skew rollers are mounted for independent movement with respect to each other. Bow corrections are made by moving the bow rollers into operative engagement with the fabric and skew corrections are made by operatively employing only the skew rollers for influencing the fabric travel. The assembly is such as the establish a differential tension across the fabric to remove a skewed-bow.

The invention provides a unique structure for establishing such differential tension, when required. The Weft alignment portion of the correction assembly interposes in the path of fabric travel alternate type correcting rollers to establish a sequence of, for example, bow roller to skew roller to bow roller to skew roller. In this way the skew roller operates or pulls against a bow roller and visa versa to establish the difierential tension for removing a skewed bow.

It is significant to note that the invention permits essentially the simultaneous application of both types of corrections when necessary in contrast with the. machines known heretofore, which sequentially apply the bow correction and then the skew correction, or the skew correction and then the bow correction. In the invention, partial skew and partial bow correction is introduced by each skew and bow roller. A closed-loop error detection and weft correction system permits such an approach.

Separate driving means is provided for the bow correcting apparatus, which is responsive to a signal indicative of the fact that the fabric includes misalignment in the form of how error. Similarly, independent driving means for the skew correcting apparatus is provided, which is responsive to skew error signals to correct for skew misalignment. A skewed-bow is corrected by driving both sets of correcting apparatus to bring all skew and bow rollers into operative engagement with the fabric to establish the desired differential tension.

Suitable apparatus for developing the skew and bow errors signals is explained in detail in the afore-rnentioned co-pending appliction, Serial No. 77,568. For purposes of this application only enough of such apparatus is described to clarify the operation of the correcting apparatus. Sufiice to say that misalignment sampling signals are developed from thread scanning devices preferably disposed near the outer or selvage edges of the travelling fabric. Each thread scanning device samples a pair of longitudinally displaced areas of the fabric-each at a predetermined orientation with respect to the fabric path-to provide a thread count comparison. From such information error indicating signals can be developed to control the skew and bow driving apparatus.

With the foregoing in mind it will be apparent that an object of this invention is to provide means which will correct skew, bow and skew-bow misalignments in the weft of woven material.

The invention has as a further object the provision of apparatus capable of establishing differential tensions across a travelling fabric, as desired, to remove skewedbow conditions therein.

A still further object of the invention is the provision of improved weft correcting apparatus through the use of skew and bow correction rollers deployed in a direct alternating sequence.

Another object of the invention is the provision of apparatus permitting the simultaneous application of partial bow and skew corrections along a section of a traveling fabric.

Further objectives and advantages of this invention will be apparent from the following description and claims wherein the construction, arrangement and cooperation of the several parts of the apparatus are set forth.

In the drawings:

FIG; 1 is a floated perspective view of the control arrangement of the invention in a preferred form;

FIG. 2 is a perspective view of a preferred weft straightening or correction assembly;

FIG. 3 is an end view of the rollers of the correction assembly of FIG. 2;

FIG. 4 is diagrammatic showing of fabric conditions; and

FIGS. 511 are diagrammatic showings of the relationship between scanned or sensed elements and various thread irregularities in the traveling strip of cloth.

Referring now to FIG. 1 there is shown an elongated strip of woven fabric 16 traveling between processing stations. The fabric is drawn through a mechanical weft straightening assembly 18 (best shown in FIGS. 2 and 3) and thence through a weft counting or sensing station generally designated by the numeral 20. After departing from the sensing station, the fabric travels to further processing stations as indicated by the arrow 19.

The fabric is'comprised of warp threads 22 running the longitudinal length of the fabric, and weft threads 2 which run laterally thereof. The longitudinal selvage edges of the fabric are designated as 26 and 28. As is well understood in the field, it is important that any lack of perpendicularity occurring between the weft and warp be promptly detected and corrected.

FIG. 4 diagrammatically shows the most common misalignments the fabric threads acquire during process ing. From top to bottom, the sectors respectively ac centuate a skew condition 30, a bow condition 31, a skewbow 32, a thick stripe condition 33, caused by contaminants, and a thick stripe condition 34 caused'by irregular warp densities. The conditions 30, 31 and'32 are the conditions correctible by the type mechanical assembly to which this invention pertains. Although conditions 33 and 34 are not correctible by roller assemblies, they are capable of transmitting false signals to the sensing devices of the prior art.

Referring to FIG. 1, counting'station 20 is equipped with four identical optical systems 36, 38, 4t and 42 for 3 providing bands of light necessary for the sensing or counting mechanism. For purposes of this description it will sufiice to say that the systems respectively furnish intensified thin bands of light 37, 39, 41 and 43 for counting purposes.

Spaced below and on both sides of the fabric at station 2t), are fabric support tables 44 and 46. The table i has two angularly disposed windows 45 and 45 therein near selvage 28, and table 46 has a like pair of angularly disposed windows 47 and 47' near selvage 26. The pairs of windows are so disposed laterally across the cloth that a linebisecting the angles formed by each pair of windows is a line perependicular to the path of fabric travel.

The intensified thin bands of light 37, 39, 41' and 43 are directed respectively at the elongated windows 47, 47', 45 and 45'. Interposed between the tables 44 and 46 and their associated light sources are a pair of scanning discs 50 and 52. The discs are geared to rotate about their respective axes 54 and 56 at the rpm. proportional to cloth speed.

Each disc is provided with a plurality of pairs of slots (not shown) which traverse the windows at exactly the same instant and at equal speeds, and thus cause synchronous beams of light to traverse the windows during the same and equal lengths of time. The traveling synchronous dots of light are modulated by the weft and Warp threads as they cross the windows. The modulated dots are indicated by the numerals 62, 64, 66 and 68. The actual scanning dots traverse the material at approximately 30 lagging and leading angles to a line drawn perpendicular to the line of material travel.

Photoelectric devices 70, 72, 74 and 76 pick up the modulated light beams and along with counters (not shown) determine the frequency with which the threads pass the windows. It is this intelligence which is processed to determine weft misalignment and compute the correction necessary.

Referring now to FIGS. 5-11, there is diagrammatically shown the alignment of the fabric threads as they pass over the windows during various conditions. The fabric in each illustration is traveling toward the top of the sheet of drawings. The thread count in windows 45', 45, 47' and 47 will arbitrarily be referred to as A, B, C and D, respectively.

In FIG. 5, the warp and weft threads are uniform and perpendicular tov each other. The thread counts A, B, C and D as the fabric passes therepast are equal and no correction signal is necessary or desired.

FIG. 7 demonstrates a forward bow (bow-lead) which results in thread count A being greater than B, and C being greater than D. Since there is a count difference.

a bow correction signal is sent to the mechanical assembly. It should be pointed out, that the difference in count between the windows of each. pair (e.g., the difference between A and B, or the difference between C and D) gives the correction indication, and not the count difference between the sum of the counts between the pairs of windows.

FIG. 6 indicates a bow-lag which makes count B greater than A, and D greater than C. As in FIG. 7, an error or correction signal is sent to the mechanical assembly and this signal is opposite in sign to that of FIG. 7.

FIG. 9 shows a skew condition in which the right side is leading. This renders count A greater than B and count C less than count D. This condition transmits a skew correction signal to the mechanical correcting assembly.

FIG. 8 demonstrates a left side leading condition which results in count B being greater than A, and count C being greater than D. This would send an error signal to the correction assembly, opposite to that discussed for the FIG. 9 condition.

FIG. 10 show a thick stripe with a skew condition.

FIG. 11 shows a thick stripe condition where the weft is correctly aligned with the warp. Here count A equals count B, counts C and D would be partially obliteratedbut would drop off substantially uniformly. As long as both pairs remain above an intelligible level, the control system remains balanced and no correction signal is sent. Conventional detection devices, comparing counts on either side of the cloth, send strong correction signals in response to such a condition.

Compare now on the other hand, FIG. 10 where there is a thick stripe condition and skew at the same instance. Count B is greater than count A, and count C is greater than count D (at least for the short period of time for which it is exposed). This condition calls for a skew correction to be sent to the mechanical assembly. It is true that if a count difference between C and D cannot be determined for long periods of time, by virtue of a fail safe circuit, no correction is sent in response to the AB count. However, starch-caused thick stripes are erratic and as a practical matter a count difference in C and B can be determined under all but the most unusual conditions. This unusual condition is detected when one or more signals drop below the critical operating signal which under current operating conditions is approximately 400 cycles per second.

As the threads both warp (some interference modulation) and weft (primarily), modulate the traveling dots of light, an electrical representation is detected by the photoelectric eyes and transferred to systems (not shown) of well known type which include counters, amplifiers, frequency detectors and a logic network. Correction signals are developed for application to the reversible electric skew motor 97- and the reversible electric bow motor 93'.

Referring now to FIGS. 1, 2 and 3, the mechanical correction assembly 13 will be described in greater detail. The assembly is supported by a suitable frame including the two parallel side frames, 191 and 193. A pair of bow rollers lit-l and 1% have their ends journaled in said side frames and are spaced with respect to each other. The rollers have straight journals 104 and 106, respectively, which extend through the side frame 101 and are held by the arms 108 and 138- of yoke 111. The yoke 111 is connected by a threaded shaft 112 for movement. The rollers lit-4 and 1% are free-wheeling and as is well known in the art, it is the position of their curved axles with respect to cloth travel which gives a bow correction. The shaft 112 operatively connected to motor 98' by way of gear box 113 transfers the desired movement to shaft 112 for pivoting of the bow rollers.

The bow correction is introduced through partial rotation of the bow rollers 10 and through the mechanism described. For example, motor 98 responds to the bow correction signal to drive screw shaft 112, thereby imparting a partial rotation to the rollers 1G4 and we. The arms 19:; and 116 are keyed to the journal 1% and lib-5', in turn iournaled in the end plate 1&1. Hence, any vertical movement of the yoke 111 imparts rotary movement to the journals 104 and 1%. Either the flexibility of the long shaft 112 or the inclusion of a universal in the gear box 1113 enables the slight lateral displacement of the shaft 11?; as it imparts rotation to the bow rollers. The yoke 1111 actually follows a slightly arcuate path determined by the fixed points where journals i594 and 196' are journaled in the end plate 191. The arms 13S and 11% are pinned to the yoke 111 to permit slight relative movement, of a pivotal nature, as the yoke is moved vertically along the arcuate path,

An upright 1&5 is pivotally mounted midway between side frames I01 and 3. 33 on cross support bars 117 and 119. A stabilizing arm 167 extends perpendicularly to the upright and supports bell cranks Mill and 132 at either end thereof.

Between the side frames and at each end of the bell cranks are two freely rotating skew rollers 116 and 11S.

which are journaled thereto. The skew rollers are vertically spaced from each other and laterally spaced from the bow rollers.

The skew roller brackets 100 and EH92 pivot laterally about the upright 105. The pivoting movement is controlled by the motor 97, the bell crank 16% being operatively connected to the skew motor via a linkage system comprised of worm box 109 and shaft 169.

As shown best in FIG. 3, the path of travel of cloth 16, is as follows: over entrance roller 12%, bow roller H24, skew roller 116, bow roller 1%, skew roller 118, measuring roller 122 and exit roller 128. It can be seen that the bow roller axes can pivot into the path of the cloth without a skew pivot and a skew-bow correction can be accomplished by pivoting brackets and 102 at the same time the bow rollers are in their operable position.

The unique sequencing of the rollers gives a much improved correction, and the dual bow and skew rollers act as a dual correction from a single bow and a single skew error signal. For correction of skewed bow, differential tension across the fabric may be established betively connected to the skew motor via a linkage system tween rollers 104 and 116, 116 and 166, and also 106 to 113, for each of these couples work or pull against each other when in operative relation.

The general operation of the entire apparatus is as follows. The fabric 16 is received by the structure of this invention from a processing center to the right or above in FIG. 3. The fabric travels through the correction assembly 18 and passes the weft sensing station 20 and departs from the sensing center to further processing centers. The optical devices 36, 38, 40 and 42 send a beam of light which is modulated by the traveling fabric and the modulated signal is picked up by the photoelectric scanning devices 7%), 72, 74 and 76. The intelligence gained by the scanning heads is sent to the logic network (not shown) which transmits signals back to the motors 97 and 98 of the mechanical correction assembly 18.

Therefore, while we have, in the above description, disclosed what we deem to be the most practical and efiicient embodiment of our invention, it should be well understood that the do not wish to be limited thereto, as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

We claim:

1. A Weft straightener comprising in combination means for guiding fabric along a predetermiend path, a series of skew and bow correcting means deployed in alternating sequence along the path, said sequence being at least skew, bow, skew, bow, means for moving the bow correcting means relative to the path to vary the path length of the farbic travel for correcting bow error, means for moving the skew correcting means relative to the path to vary the path length of the fabric travel for correcting skew error, and means for endering both the bow and skew correcting means simultaneously operative to vary the path for correcting a bowed-skew.

'2. A weft straightener mechanism comprising in com bination frame means; a plurality of rollers supported for rotation by the frame means to form a path for fabric to be straightened; said rollers including a series of skew type correcting rollers and a series of bow type correcting rollers deployed respectively in alternating sequenec along the path for the fabric with adjacent rollers being of diiferent types; means to cant said skew correcting rollers simultaneously relative to the fabric path to correct weft skew; and means for imparting partial rotation to the bow correcting rollers simultaneously to correct weft how by altering the length of the fabric path through the mechanism, both said skew correcting rollers and said bow correcting rollers being simultaneously operative to vary the fabric path to correct bowed-skew.

3. A weft straightener mechanism comprising in combination frame means; a plurality of rollers supported for rotation by the frame means to form a path for fabric to be straightened; said rollers including a series of type skew correcting rollers and a series of bow type correcting rollers deployed respectively in alternating sequence along the path for the fabric with adjacent rollers being of different types; said frame means including means supporting collectively the skew correcting rollers for lateral movement relative to the fabric for introducing skew correction thereto; skew correcting drive means responsive to a skew correction signal to cant said rollers via the supporting means simultaneously relative to the fabric path; said bow rollers being arcuate; means for imparting rotation to the bow correcting rollers to correct for Weft bow by altering the length of the fabric path through the mechanism; and bow correcting driving means responsive to a bow correcting signal to impart movement to said last-mentioned means in accordance with said signal, both said skew correcting rollers and said how correcting rollers being simultaneously operative to vary the fabric path to correct bowed-skew.

References Cited by the Examiner UNITED STATES PATENTS 1,384,213 7/21 Rowley 26-51 2,623,262 12/52 Berry 2651.5 2,638,656 5/53 Tuttle et al. 26-515 2,968,856 1/61 Allen 26-515 2,972,794 2/61 Saul et al. 2651.5

FOREIGN PATENTS 579,505 8/24 France.

761,830 11/56 Great Britain.

DONALD W. PARKER, Primary Examiner.

RUSSELL C. MADER, Examiner.

Claims (1)

1. A WEFT STRAIGHTENER COMPRISING IN COMBINATION MEANS FOR GUIDING FABRIC ALONG A PREDETERMINED PATH, A SERIES OF SKEW AND BOW CORRECTING MEANS DEPLOYED IN ALTERNATING SEQUENCE ALONG THE PATH, SAID SEQUENCE BEING AT LEAST SKEW, BOW, SKEW, BOW, MEANS FOR MOVING THE BOW CORRECTING MEANS RELATIVE TO THE PATH TO VARY THE PATH LENGTH OF THE FABRIC TRAVEL FOR CORRECTING BOW ERROR, MEANS FOR MOVING THE SKEW CORRECTING BOW ERROR, MEANS FOR MOVTHE PATH LENGTH OF THE FABRIC TRAVEL FOR CORRECTING SKEW ERROR, AND MEANS FOR ENDERING BOTH THE BOW AND SKEW CORRECTING MEANS SIMULTANEOUSLY OPERATIVE TO VARY THE PATH FOR CORRECTING A BOWED-SKEW.

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