Apparatus for disposing of weft yarn piece in a jet loom

Abstract

 The apparatus for disposing of a weft (Y₃) piece in a jet loom comprises a pair of weft piece sensors (23A, 24A; 23B, 24B), disposed at the terminal side of weft picking passage. If a weft yarn breaks, the weft piece withdrawing device withdraws one piece (Y₃) of the broken weft with a pair of weft piece withdrawing rollers (27, 29) disposed between said paired weft piece sensors (21A, 22A; 23A, 24A; 23B, 24B).
The withdrawing rollers (27, 28) form, when put together a drum, that serves as a measuring drum for the weft yarn piece when it is wound on that drum. Another weft yarn withdrawing device (8, 9, 11, 12, 17, 16, 17, 18) placed at the entering side of the weft picking passage, provides for withdrawing the weft yarn piece (Y₁) upstream the breaking point of the broken weft (Y). The withdrawing devices generate signals representative for the length of the withdrawn yarn pieces (Y₁, Y₃) of the broken weft. These signals are fet to a computer (C). In this computer (C) the sum of the length of the yarn pieces is compared with the preset nominal weft yarn length. If the sum of the removed yarn pieces is equal or greater than the nominal weft length the loom is automatically restarted; this based on the assumption that the broken weft has been totally removed. If the sum of the pieces is shorter than the nominal weft length, the loom is not restarted and calls for service personnel care.

Description

[0001] The present invention relates to an apparatus in a jet loom for removing from fabric a piece of weft that has been picked incompletely.

[0002] An apparatus in a jet loom for removing a faulty weft that has been picked incompletely and beaten to a fabric is disclosed by the Japanese Patent Application JP 62-215047. In this prior art apparatus, the faulty weft is left integrally continuous with its succeeding weft portion without being cut off therefrom and the former faulty weft beaten at fabric cloth fell is withdrawn laterally from a warp shed by pulling the latter succeeding weft portion. The apparatus has a weft withdrawing device including a pair of rollers disposed adjacently to the terminal end of weft picking path for pulling a weft piece that has been cut off from the faulty weft and remains in the warp shed.

[0003] It is noted that the above cut weft piece remaining in the warp shed may possibly fail to be removed completely. In such a case, a weft piece remaining in the shed will be woven into a fabric when loom operation is resumed automatically after normal removal of the faulty weft. The prior art apparatus is disadvantageous in that it is unable to cope with unexpected failure in withdrawing from the warp shed such cutoff weft piece.

[0004] Accordingly, it is an object of the present invention to provide an apparatus in a jet loom for disposing of a cut weft piece, which permits the loom to resume its weaving operation without allowing the cut weft piece to be woven into a fabric.

[0005] To achieve the above objective, the present invention provides an apparatus comprising a pair of weft piece sensors disposed on the terminal side of weft picking passage, a weft piece withdrawing device including a pair of weft piece withdrawing rollers disposed between said paired weft piece sensors for pulling and removing a weft piece, which has been cut off from a picked yarn, laterally out of a warp shed, said withdrawing device being operable to pull the opposite end portions of said weft piece on opposite sides of said weft piece withdrawing rollers toward said rollers, and means for measuring the length of said weft piece on the basis of information of weft piece presence/absence detected by said weft piece sensors and information of number of rotation of said weft piece withdrawing rollers.

[0006] In operation, a weft piece cut off from an improperly picked weft is held by the paired weft piece withdrawing rollers and the opposite end portions of the weft piece are pulled toward the rollers. The weft piece sensor disposed on the upstream side of the paired rollers detects the end portion of weft piece withdrawn for removal from a warp shed, while the weft piece sensor on the opposite downstream side detects the end portion that had moved past the region of the rollers. Therefore, the length of the weft piece end portion extending upstream of the paired rollers can be measured from the period of time during which that end portion is being detected by the upstream weft piece sensor and the amount that the rollers rotated during that detecting period of time. Similarly, the length of the weft piece end portion extending downstream of the rollers can be determined from the period of time during which that end portion is being detected by the downstream weft piece sensor and the amount that the rollers rotated during that detecting period of time. Thus, the total length of the cut-off weft piece can be determined from the above information.

[0007] The following will describe an embodiment of the invention while referring to the accompanying drawings including. Figs. 1 through 7 show an embodiment of the apparatus for disposing of a weft piece in a jet loom according to the present invention and parts thereof:

[0008] The drawings show the following:

Fig. 1 (a) is a schematic plan view of a jet loom having incorporated therein the apparatus, showing a condition wherein a picked weft is broken within the range of weaving width of the loom;

Fig. 1 (b) is a similar schematic plan view showing a condition wherein a break has occurred in the weft upstream of the main weft picking nozzle;

Fig. 2 is a perspective view showing a weft withdrawing device disposed on the upstream side of weft insertion;

Fig. 3 is an enlarged sectional front view showing a condition wherein the leading end of a weft piece has reached the interior of a suction pipe;

Fig. 4 (a) is a schematic plan view of the jet loom showing a condition wherein a faulty weft is being withdrawn by the weft withdrawing device on the upstream side;

Fig. 4 (b) is a similar schematic plan view showing a condition wherein the slay of the loom is fully retracted;

Fig. 5 (a) is an enlarged sectional front view showing a condition wherein a weft piece is held by a pair of rollers;

Fig. S (b) is a sectional view taken along the line A-A of Fig. 5 (a);

Fig. 6 (a) is an enlarged sectional front view showing a condition wherein the weft piece is being wound round the periphery of the paired rollers;

Fig. 6 (b) is a sectional view taken along the line B-B of Fig. 6 (a);

Fig. 7 (a)-(d) provide flow chart diagrams showing a program for disposing of weft piece;

Figs. 8 and 9 are schematic plan views showing another embodiment of the apparatus according to the present invention.Weft piece withdrawing device including stepping motor 26 and air cylinder 28; Weft piece withdrawing rollers 27, 29; Weft piece sensors 21A, 22A; Computer control C as means for measuring the weft piece.

[0009] Referring firstly to Fig. 1, a weft picking main nozzle 2 is mounted on a slay 1 at one end thereof and adapted to receive therethrough a weft yarn having a predetermined length measured by a winding type weft measuring and storage device 3. The weft is flown by air jet from the main nozzle 2 synchronously with the loom rotation into a weft picking passage 4a (Fig. 2) formed by dents of a reed 4 disposed projecting upwardly from the slay 1. Windings of weft on the winding surface 3a of the weft measuring and storage device 3 is released therefrom by moving a stop pin 5a out of engagement with the winding surface 3a. Operation of the stop pin 5a is controlled by an electromagnetic solenoid 5.

[0010] The weft thus injected out of the main nozzle 2 is subjected to the influence of relayed air jets from a plurality of auxiliary nozzles 20, 20A disposed in series to carry the weft through an open shed then formed by upper and lower sheets of warp yarns. The leading end of the weft thus picked through the shed reaches a weft sensor 6 disposed at a position further than the last auxiliary nozzle 20A and immediately outside the warp shed. The weft sensor 6 is adapted to detect the weft leading end so as to ascertain the presence of a weft within a predetermined range of rotational angles of the weaving loom, thus determining whether or not weft picking has been performed completely. Information from the weft sensor 6 representative of presence or absence of a weft is transmitted to a computer control C, which in response thereto commands a loom drive motor M to continue or interrupt its operation. When weft picking is performed properly, it is beaten by the reed 4 to be woven to cloth fell W1 of fabric W. The beaten-up weft is cut by an electromagnetically-operated cutter 7 disposed on the side of the main nozzle 2. Thereafter, the weaving operation is continued.

[0011] If the leading end of a weft fails to reach the weft sensor 6, the sensor generates a signal representative of failure in weft picking and the computer control C responding to the signal immediately commands the loom drive motor M to stop its operation. The weaving loom is rotated by inertia for about one complete turn after generation of above signal. That is, the picking-failure signal is generated while the slay 1 is being swung toward the fabric W from its retracted position, and the slay 1 further makes a reciprocatory movement after the faulty weft, i.e. the weft resulting from picking failure, has been beaten to the fabric W, until the slay reaches immediately before the beating position, as shown by phantom line in Fig. 1. In response to the picking-failure signal, the electromagnetic cutter 7 is rendered inoperative and, therefore, the faulty weft woven to the cloth fell W1 is left integral with its succeeding weft portion without being cut off therefrom.

[0012] As shown in Fig. 2, immediately below the main picking nozzle 2 is provided a blow nozzle 8 which is connected to any suitable source of air under pressure (not shown) and has its outlet 8a directed across the direction of air jet issued from the main nozzle 2. Immediately above the main nozzle 2 is provided a weft guide 9 having its weft introducing inlet 9a (Fig. 1) positioned in confrontation with the outlet 8a of the blow nozzle 8 so that the air jet region of the main picking nozzle 2 just lies therebetween. The blow nozzle 8 and weft guide 9 are both mounted for movement together with the main picking nozzle 2 fixed on the slay 1. A stationary cutter 10 is disposed between the inlet 9a of the weft guide 9 and the outlet of the main picking nozzle 2.

[0013] Adjacently to the outlet 9b of the weft guide 9 is pro vided an air guide 11 and a suction pipe 12 both movable together with the main picking nozzle 2. The air guide 11 and the suction pipe 12 are arranged with the inlet and outlet of the former and the inlet of the latter axially aligned with the outlet 9b of the weft guide 9. The suction pipe 12 is bent so as to direct its outlet toward a dust box (not shown) located forwardly of the swinging region of the slay 1. The suction pipe 12 has a blow nozzle 13 connected to the above air source and fitted to the bent portion of the suction pipe 12 for directing air under pressure toward its outlet.

[0014] Behind the swinging region of the slay 1, there is a stepping motor 14 which is operatively connected to a drive roller 15 through sprocket and belt drive. The stepping motor 14 is operable from pulse signals transmitted by the computer control C. Above the drive roller 15 is disposed an air cylinder 16 having its piston rod (now shown) directed downward. The piston rod end of the cylinder 16 carries a support frame 16a in which a follower roller 17 is rotatably supported with its axis in parallel to that of the drive roller 15. Actuation of the air cylinder 16 extends its piston rod, causing the follower roller 17 to be moved into contact engagement with its associated drive roller 15.

[0015] The stepping motor 14, air cylinder 16 and paired rollers 15, 17 comprise part of first weft withdrawing device. The device further includes a support member 18 pivotally supported at an upper corner thereof by a shaft 31 on a lateral side of the air cylinder 16 and having at its lower portion an arcuate guide slit 18a through which a guide pin 16b projecting from the support frame 16a is inserted. The support member 18 has a weft sensor 19 with a weft feeler arm 19a.

[0016] The paired rollers 15, 17 of the first weft withdrawing device provide a nip therebetween in the region between the weft guide 9 and air guide 11 when they are moved back to their retracted position together with the slay 1. The weft feeler arm 19a of the weft sensor 19 is movable to sweep across the region between the air guide 11 and suction pipe 12 when the cylinder 16 is actuated to extend in the above retracted position of the slay 1.

[0017] As shown in Figs. 1 and 3, there is provided a pair of weft guides 21, 22 fixed on the slay 21 adjacently to and on the downstream side of the weft sensor 6 with respect to the direction of weft movement. Further than the weft guides 21, 22, there is a bent suction pipe 30 fixedly mounted on the slay 1. The suction pipe 30 has a blow nozzle 32 fitted to its bent portion and operable to generate an air flow creating vacuum at the inlet of the pipe 30.

[0018] The weft guide 21 has an inlet with a convergent configuration as viewed along the weft movement, and the auxiliary nozzle 20A is positioned to direct its air jet toward that inlet of the weft guide 21. Such arrangement helps to introduce most of the air jet from the auxiliary nozzle 20A into the weft guide 21.

[0019] The weft guide 21 has incorporated therein a light emitting element 23A and its associated light receiving element 24A in facing relation to each other on opposite sides in the weft passage of the guide 21. The weft guide 21 further includes a bar-shaped lens 25A positioned between the light emitter 23A and light receiver 24A. As seen in Fig. 3, the bar lens 25A has a semicircular-shaped section to focus the light projected by the light emitter 23A into a parallel ray sweeping substantially all the transverse cross-sectional area of the weft passage in the weft guide 21. These light emitter 23A, light receiver 24A and bar lens 25A constitute first weft piece sensor 21A.

[0020] The other weft guide 22 has also incorporated therein similar light emitter 23B, light receiver 24B and bar lens 25B, which altogether constitute second weft piece sensor 22A.

[0021] A stepping motor 26 having its output shaft projecting upward is provided just behind the retracted slay 1 on the terminal side of weft insertion. This stepping motor 26 is also is operable from pulse signals from the computer control C. The output shaft carries thereon a drive roller 27. As seen in Fig. 3, an air cylinder 28 having its piston rod projecting downward is located just above the stepping motor 26 and the piston rod of the air cylinder 28 rotatably carries thereon a follower roller 29. The paired rollers 27, 29 have their end surfaces 27a, 29a in facing relation to each other so that extending operation of the air cylinder 28 causes the end surface 29a of the roller 29 to be brought into contact engagement with the end surface 27a of the counterpart roller 27. The rollers 27, 29 are so arranged that the region of contact engagement between the end surfaces 27a, 29a lies just between the weft guides 21, 22 as positioned when the slay 1 is fully retracted, whereby a weft piece coming out of the weft picking passage 4a and having its leading end reaching the weft guide 22 is caught and held by and between the rollers 27, 29.

[0022] As indicated by reference numerals 27b, 29b, the paired rollers 27, 29 are tapered toward the inner ends thereby to form a V-shaped annular groove around the rollers 27, 29 when their end surfaces 27a, 29a are set in contact engagement, as seen clearly in Fig. 5 (a).

[0023] The aforementioned blow nozzles 8, 13, 32 and air cylinders 16, 28 are connected to the source of air under pressure (not shown) via solenoid-operated valves V1, V2, V5, V3, V4, respectively. Operation of these valves V1, V2, V3, V4, V5 and of the stepping motors 14, 26 is controlled by command signals or pulse signals from the computer control C, which is in turn operable from various signals transmitted from the weft sensors 6, 19 and weft piece sensors 21A, 22A.

[0024] In the event of an occurrence of failure in complete weft picking, the computer control C executes a control program according to flow chart diagrams shown in Fig. 7 (a) through (d).

[0025] If a picked weft has failed to reach the position defined by the weft sensor 6, i.e. if the weft sensor 6 has failed to detect the leading end of the picked weft within a predetermined range of rotational angles of the weaving loom, the computer control C, then responding to a picking-failure signal from the weft sensor 6, sets the cutter 7 inoperative and causes the loom drive motor M to interrupt its operation. Simultaneously, the control C energizes (or turns on) the solenoids of valves V1, V2. Thus, the blow nozzles 8, 13 are both opened thereby to produce air flows, one between the blow nozzle 8 and weft guide 9 flowing across the air jet from the main picking nozzle 2 and thus impeding the weft picking air jet, and the other flowing in the suction pipe 12 to create vacuum at its inlet.

[0026] The blow nozzles 8, 13 are operated to open before the slay 1 reaches the position shown in Fig. 1. The faulty weft Y1 is woven to the cloth fell W1, while the weft portion Y2 downstream of the cutter 7 that succeeds the faulty weft Y1 without being cut off therefrom is drawn out from the weft measuring and storage device 3 by air flow from the blow nozzle 8 and introduced into the weft guide 9. The weft portion Y2 is carried moving through the air guide 11 and into the suction pipe 12, from which it is blown toward the dust box (not shown) by air flow from the blow nozzle 13. This air flow from the blow nozzle 13 helps keep the weft portion Y2 under an appropriate tension.

[0027] Subsequent to the stop of the weaving loom, the computer control C responding to a signal from a rotary encoder 33 causes the loom to rotate reversely for a predetermined amount so as to bring the slay 1 to its retracted position as shown in Fig. 4 (a). In this position where the slay 1 is fully retracted, a wide-open shed is formed by upper and lower sheets of warp yarns and the faulty weft Y1 is released from its woven condition. Simultaneously with the retraction of the slay 1, part of the weft portion Y2 extending between the weft guide 9 and air guide 11 is moved into the nipping region of the paired rollers 15, 17 and another part of the weft portion Y2 extending between the air guide 11 and suction pipe 12 is brought into the sweeping region of the feeler arm 19a of the weft sensor 19. After the loom has been reversed to the above position, the solenoid for valve V1 is deenergized (or turned off) to close the blow nozzle 8 thereby stopping air flow therefrom into the weft guide 9. In this condition, the solenoid for valve V3 is energized to actuate the air cylinder 16, thereby moving the roller 17 into contact engagement with its associated roller 15.

[0028] Downward movement of the roller 17 causes the support member 18 to pivot about the shaft 31 with the guide pin 16b moved along the arcuate slit 18a, thus urging the feeler arm 19a of the weft sensor 19 to move across the region between the air guide 11 and suction pipe 12. If a weft portion such as the portion Y2 is then absent between the rollers 15, 17, the feeler arm 19a moves integrally with the weft sensor 19 and the latter sensor does not generate a weft-detected signal. If the computer control C fails to receive such a weftdetected signal from the weft sensor 19 within a predetermined period of time, the control C determines that a trouble has occurred in weft handling. Accordingly, a warning lamp 34 is illuminated and the solenoids for valves V2, V3 are turned off to stop air flow from the blow nozzle 13 and move the roller 17 away from its counterpart roller 15.

[0029] If a weft portion such as the weft portion Y2 is present between the rollers 15, 17, the feeler arm 19a, whose movement is then stopped by the weft portion under tension, makes a relative rotational motion with respect to the movement of the weft sensor 19. This allows the weft sensor 19 to transmit a weft-detected signal to the computer control C. In response to this signal, the control C activates the stepping motor 14 thereby to rotate the rollers 15, 17 with the weft portion Y2 nipped therebetween. Tension of the weft portion Y2 is increased by the rotation of the rollers 15, 17 which pull the weft portion toward the suction pipe 12, and this increased tension allows the stationary cutter 10 to cut the yarn portion Y2 at the outlet of the main picking nozzle 2. Simultaneously, the faulty weft Y1 at the cloth fell W1 is pulled out therefrom by the rollers 15, 17.

[0030] The faulty weft Y1 removed from the cloth fell W1 is moved toward the suction pipe 12 by the rotating rollers 1S, 17. The weft sensor 19 continues to transmit the weft-detected signal to the computer control C as long as the weft Y1 is being pulled by the rollers 15, 17. When the weft-detected signal is produced no more by the weft sensor 19, the control C commands the stepping motor 14 to stop and the solenoids of valves V2, V3 to be deenergized to close the blow nozzle 13 and move the roller 17 away from the roller 15. Then, the computer control C determines, on the basis of the number of pulse signals that the computer control C transmitted to the stepping motor 14 while the weft-detected signal from the weft sensor 19 remains effective, the length "x1" of the faulty weft Y1 withdrawn from the warp shed.

[0031] If the withdrawn weft length "x1" is greater than a value "X0" corresponding a predetermined weft picking length, the computer control C allows the weaving loom to resume its operation. If "x1" is smaller than "X0",however, the computer control C commands the loom to indicate "x1<X0" on a display unit 35, with simultaneous illumination of the warning lamp 34.

[0032] In the event that a break has occurred in the faulty weft Y1 as shown in Fig. 1 (a), its preceding weft piece Y3 is detected by the weft piece sensors 21A, 22A. In response to weft-detected signals from the sensors 21A, 22A, the computer control C energizes the solenoids of valves V1, V2, thereby producing the above air flow between the blow nozzle 8 and wet guide 9 that impedes the air jet from the main picking nozzle 2 and also vacuum at the inlet of the suction pipe 12. Simultaneously, the loom operation is interrupted.

[0033] The weft piece sensors 21A, 22A continue to transmit the weft-detected signal to the computer control C while the weft piece Y3 is being detected. When the period of time of the weft-detected signal transmission exceeds a predetermined time, the control C commands weft withdrawing operation by the aforementioned first weft withdrawing device to dispose of the weft Y1 in the same manner as described earlier.

[0034] After operation of the first weft withdrawing device has been completed, the computer control C commands weft withdrawing operation by second weft withdrawing device which includes the stepping motor 26, air cylinder 28 and the paired rollers 27, 29. That is, firstly the solenoid for valve V4 is energized to actuate the cylinder 28, thereby moving the end surface 29a of the roller 29 into contact engagement with the counterpart end surface 27a of the roller 27. Thus, the weft piece Y3 is held between the end surfaces 27a, 29a of the paired rollers 27, 29.

[0035] After the actuation of the cylinder 28, the stepping motor 26 is activated, so that the weft piece Y3 is wound round the tapered peripheral surfaces 27b, 29b of the rollers 27, 29 until the both end portions Y31, Y32 are taken up. During the above winding, the trailing end portion Y31 of the weft piece Y3 extending upstream of the region of the paired rollers 27, 29 is detected by the weft piece sensor 21A, and the computer control C continues to receive the weftdetected signal from the sensor 21A until the end portion Y31 moves past the sensor. On the other hand, the leading weft portion Y32 of the same weft piece Y3 extending upstream of the above region is detected by the weft sensor 22A, and the computer control C similarly continues to receive the weftdetected signal from the weft piece sensor 22A until the end portion Y32 moves past the sensor.

[0036] When no weft-detected signal is transmitted by both of the weft piece sensors 21A, 22A, the computer control C commands the stepping motor 26 to be stopped and the solenoid of valve V4 to be deenergized and, after elapse of a predetermined period of time, commands the solenoid of valve VS to be deenergized. Accordingly, the roller 29 is moved away from its associated roller 27 and the weft piece Y3 then wound up on the tapered peripheral surfaces 27b, 29b of the rollers 27, 29 is pulled into the suction pipe 30 in which vacuum is then produced. The vacuum in the pipe 30 disappears after the weft piece Y3 has been discharged through the pipe.

[0037] On the basis of the number of pulse signals that the computer control transmitted to the stepping motor 26 while the weft-detected signal from the weft piece sensor 21A is effective, the control figures out the length "x2"' of the weft end portion Y31 of the weft piece Y3. The computer control C also determines the length "x3"′ of the weft end portion Y32 on the basis of the number of pulses that the control transmitted to the stepping motor 26 while the weft-detected signal from the weft piece sensor 22A is effective. The computer control C then determines "x2", i.e. the sum of the above weft winding length "x2"′ and distance "d1" (Fig. 6 (b)) as measured between the weft piece sensor 21A and the winding position of the weft end portion Y31 on the paired rollers 27, 29, and "x3", i.e. the sum of the above weft winding length "x3"′ and distance "d2" as measured between the weft piece sensor 22A and the winding position of the weft end portion Y32 on the rollers. Namely, the value of "x2" represents the wound length of the weft end portion Y31 and "x3" the wound length of the weft end portion Y32.

[0038] Therefore, the total length of the weft piece Y3 can be expressed by the sum of the wound lengths "x2+x3" and the diameter "d", shown in Fig. 6 (b), of the paired rollers at their ends 27a, 29a. When the sum "X" of the length "x2+x3" of the weft piece Y3 and the length "x1" of the weft withdrawn by the paired rollers 15, 17 of the first weft withdrawing device, i.e. "X = x1+x2+x3+d", is equal to or greater than a aforementioned length "XO", the computer control C commands the loom to resume its operation. If "X" is smaller than "XO", the control C commands an alarm by the warning lamp 34.

[0039] A condition of "x1+x2+x3+d< XO" can result, for example, from a break occurring in the faulty weft Y1 or weft piece Y3 during its withdrawing. If the loom operation is resumed without applying any remedy for such a break, part of the faulty weft Y1 or the weft piece Y3 will be woven into a fabric W. In the above-described embodiment according to the invention wherein the withdrawing lengths of the faulty weft Y1 and of the weft piece Y3 are measured and the computer control C will not command resumption of weaving operation of the loom when the total withdrawn length is less than a predetermined value, there is no fear that a piece or portion of weft is left in a warp shed and woven into a fabric.

[0040] When the weft piece Y3 wound on the paired rollers 27, 29 is withdrawn toward the suction pipe 30, it is detected by the weft sensor 22A. If the computer control C fails to receive a weft-detected signal from the weft sensor 22A for a predetermined period of time, the control commands indication of the measurements "x1", "x2", "x3", "X"and the value "XO" on the display unit 34.

[0041] If the weft piece Y3 is caught by the weft guide 21 for some reason, the computer control C fails to receive information from the weft piece sensor 22A representative of weft absence. When such weft-absence signal is not received for a predetermined period of time, the control C commands similar indication on the display unit 34.

[0042] Referring to Fig. 1 (b) and Fig. 4 (b) showing a condition wherein a break has taken place in the weft upstream of the main picking nozzle 2. In such a case of failure in weft supplying, a series of operations is performed by both first and second weft withdrawing devices according to the program shown in Fig. 7 (a) - (d), but operation of the loom will not be resumed.

[0043] It is to be understood that the present invention is not limited to the above-described embodiment, but it may be practiced in various modifications as exemplified in Figs. 8 and 9.

[0044] In the embodiment in Figs. 8 and 9, there is provided a mounting block 36 which carries thereon weft guides 21, 22 having incorporated therein weft piece sensors 21A, 22A, respectively, a stepping motor 26, an air cylinder (not shown) having a follower roller, and a suction pipe 30. The mounting block 36 is supported by an air cylinder 37 so as to be reciprocally movable toward and away from the slay 1. The mounting block 36 is normally located at a position where the weft guide 21 can receive a weft coming out from a warp shed as indicated in Fig. 8, but moved to a position corresponding to the retracted position of the slay 1 when a weft piece Y3 is to be withdrawn. This movement of the mounting block 36 permits easy withdrawal of the weft piece Y3 because it is pulled out from the cloth fell W1 with a relatively large angle with respect to the cloth fell W1, as shown in Fig. 9. The mounting block 36 is moved toward the retracted position of the slay 1 with the weft piece Y3 held between the paired rollers 27, 29.

[0045] Additionally, it may so arranged that portion of the weft piece Y3 between sensors 21A, 22A is held by the peripheral surfaces of paired rollers in a double-folded state and pulled toward between the peripheral surfaces.

[0046] As it is apparent from the foregoing description, according to the present invention, both end portions of a cutoff weft piece are pulled by a pair of weft piece withdrawing rollers arranged between a pair of weft piece sensors disposed on the terminal side of weft picking passage, and the length of the weft piece is measured from the period of time during which both end portions are being detected by the respective weft piece sensors and the amount that the rollers rotated during the respective detecting periods of time. Thus, the present invention offers an advantageous effect that the length the weft piece can be measured accurately while withdrawing it from a warp shed.

[0047] Second means for detecting and for removing warp, that disposed at the entering side of the weft picking passage do also including means for measuring the length of a piece of weft. Such information may also be collected on the basis of detecting presence/absence of the weft piece by sensors and in addition on the basis of information of the number of rotation of weft piece withdrawing rollers. In this case the removing and measuring device may be of a similar design as the one placed at the terminal side of the weft picking passage.

[0048] The apparatus for disposing of a weft Y3 piece in a jet loom comprises a pair of weft piece sensors 23A, 24A; 23B, 24B, disposed at the terminal side of weft picking passage. If a weft yarn breaks, the weft piece withdrawing device withdraws one piece Y3 of the broken weft with a pair of weft piece withdrawing rollers 27, 29 disposed between said paired weft piece sensors 21A, 22A; 23A, 24A; 23B, 24B

[0049] The withdrawing rollers 27, 28 form, when put together a drum, that serves as a measuring drum for the weft yarn piece when it is wound on that drum. Another weft yarn withdrawing device 8, 9, 11, 12, 17, 16, 17, 18 placed at the entering side of the weft picking passage, provides for withdrawing the weft yarn piece Y₁ upstream the breaking point of the broken weft Y. The withdrawing devices generate signals representative for the length of the withdrawn yarn pieces Y₁, Y₃ of the broken weft. These signals are fet to a computer C. In this computer C the sum of the length of the yarn pieces is compared with the preset nominal weft yarn length. If the sum of the rmoved yarn pieces is equal or greater than the nominal weft length the loom is automatically restarted; this based on the assumption that the broken weft has been totally removed. If the sum of the pieces is shorter than the nominal weft length, the loom is not restarted and calls for service personnel care.

[0050] Figs. 1 through 7 show an embodiment of the apparatus for disposing of a weft piece in a jet loom according to the present invention: of which Fig. 1 (a) is a schematic plan view of a jet loom having incorporated therein the apparatus, showing a condition wherein a picked weft is broken within the range of weaving width of the loom; Fig. 1 (b) is a similar schematic plan view showing a condition wherein a break has occurred in the weft upstream of the main weft picking nozzle; Fig. 2 is a perspective view showing a weft withdrawing device disposed on the upstream side of weft insertion; Fig. 3 is an enlarged sectional front view showing a condition wherein the leading end of a weft piece has reached the interior of a suction pipe; Fig. 4 (a) is a schematic plan view of the jet loom showing a condition wherein a faulty weft is being withdrawn by the weft withdrawing device on the upstream side; Fig. 4 (b) is a similar schematic plan view showing a condition wherein the slay of the loom is fully retracted; Fig. 5 (a) is an enlarged sectional front view showing a condition wherein a weft piece is held by a pair of rollers; Fig. S (b) is a sectional view taken along the line A-A of Fig. 5 (a); Fig. 6 (a) is an enlarged sectional front view showing a condition wherein the weft piece is being wound round the periphery of the paired rollers; Fig. 6 (b) is a sectional view taken along the line B-B of Fig. 6 (a); Fig. 7 (a) - (b) provides flow chart diagrams showing a program for disposing of weft piece; Figs. 8 and 9 are schematic plan views showing another embodiment of the apparatus according to the present invention. Weft piece withdrawing device including stepping motor 26 and air cylinder 28; Weft piece withdrawing rollers 27, 29; Weft piece sensors 21A, 22A; Computer control C as means for measuring the weft piece.

Claims

1. An apparatus for disposing of a weft piece in a jet loom comprising:
   a pair of weft piece sensors (21A, 22A) disposed on the terminal side of weft picking passage;
   a weft piece withdrawing device including a pair of weft piece withdrawing rollers (27, 29) disposed between said paired weft piece sensors (21A, 22A) and for pulling and removing a weft piece (Y₃), which has been cut off from a picked yarn, laterally out of a warp shed, said withdrawing device operable to pull the opposite end portions of said weft piece (Y₃) on opposite sides of said paired weft piece withdrawing rollers (27, 29) toward said rollers (27, 29).
   and means (14, C) for measuring the length of said weft piece (Y₃) on the basis of information of weft piece presence/absence detected by said weft piece sensors (21A, 22A) and information of number of rotation (14, C) of said paired weft piece withdrawing rollers (27, 29).

2. An apparatus for disposing of a weft piece in a jet loom comprising:
   at least a pair of weft piece sensors (21A, 22A) disposed on the terminal side of weft picking passage;
   a weft piece withdrawing device including a pair of weft piece withdrawing rollers (27, 29) disposed between said paired weft piece sensors (21A, 22A) for pulling and removing a weft (Y3) piece, which has been cut off from a picked yarn, laterally out of a warp shed, said withdrawing device (26, 27, 29) operable to pull the opposite end portions of said weft piece (Y₃) on opposite sides of said paired weft piece withdrawing rollers (27, 29) toward said rollers (27, 29),
   and means for measuring (26, C) the length of said weft piece (Y₃) on the basis of information of weft piece (Y₃) presence/absence detected by said weft piece sensors (21A, 22A) and information of number of rotation (26) of said paired weft piece withdrawing rollers (27, 29).

3. An apparatus as claimed in claim 1 or 2, comprising
   second means (8, 9, 11, 12, 17, 16, 17, 18) for detecting and for removing weft (Y₁) and disposed on the entering side of the weft picking passage and
   including means (15, 16, 17) for measuring the length of said weft piece (Y₁) on the basis of information of weft piece presence/absence detected by said weft piece sensors (6, 21A, 22A) and information of number of rotation (14, C) of said paired weft piece (Y₁) withdrawing rollers (15, 17).

4. An apparatus as claimed in claim 3, wherein the means for withdrawing and measuring the lenght of the withdrawn weft yarn pieces (Y₃, Y₁) are working according to similar function principles.

5. An apparatus as claimed in any of claims 1 to 4, comprising means (C) for inhibiting the action of the weft yarn cutter (10) at the entering side of the weft into the warp shed when the weft yarn insertion detecting sensor (6, 21A, 22A) detect break of a weft yarn.

6. A jet loom comprising an apparatus for disposing of a piece of weft as claimed in any of claims 1 to 5.

7. Method to use an apparatus as claimed in any of claims 1 to 6 on an air jet loom with
   each at the beginning side and at the terminal side of the weft picking passage, a weft withdrawing device for withdrawing pieces of broken weft, and
   each of said devices including a measuring device for measuring the length of the pieces of the broken weft yarn and
   wherein signals, representative for the length of the individual withdrawn yarn pieces are generated by the withdrawing devices and fed to a computing and comparing device that
   compares the total length of the withdrawn weft yarn with the preset nominal weft length and
   generates a loom-start signal under the condition that the total length of the withdrawn weft yarn pieces is equal or greater than said preset nominal weft length.

8. Method according to claim 7, wherein said computing and comparing device generates an alarm signal under the condition that, the total measured length of the withdrawn weft yarn pieces is lower than said preset nominal weft length.

9. Method according to claim 7 or 8, wherein said computing and comparing device generates hold stop signal under the condition, that the total measured length of the withdrawn weft yarn pieces is lower than said preset nominal weft length.

Drawing