Weft yarn handling apparatus in a jet loom

Abstract: The weft yarn handling apparatus for a jet looms includes means (8a) for unwinding the weft from a weft supply cheese (3). The length of the unwound weft yarn (Y) is measured and the yarn is stored on a drum (8b) of the measuring and storing device (8) The weft (Y) thus measured and reserved is then transferred to the main nozzle (13) of an air jet loom and then inserted through the shed by fluid injected from the main picking nozzle (13). On the downtream side of the weft measuring and storage device (8) there is a nozzle block arrangement (15; 12, 8a, 15a, 15b, 16) for transferring weft yarn from the measuring and storage device (8) to the main nozzle 13 and in addition means (40) for retaining weft yarn in the case of a weft yarn break. The nozzle block further includes means (22) for cutting the weft (Y) at a predetermined position while said part of the weft (Y) is being retained by said retaining means (40). One cut end of weft yarn (Y) is blown or sucked to a trash box (19) and the other end is guided to the region of suction adjacent to the inlet of weft injection main nozzle (13). The arrangement is operated automatically by a control C, that starts operating when a weft yarn break is detected that required threading of the main nozzle (13). The arrangment provides for a non complicated, fast threading of the main nozzle (13) and low failure rate.

Description: The present invention relates to a weft handling apparatus in a jet loom for threading a main weft picking nozzle of the loom with a new weft end subsequently to changing of a weft cheese or to a failure in weft feeding due to a weft break between the weft cheese and main weft picking nozzle. Conventional weft handling apparatuses of the above type are disclosed by Publications of Japanese Patent Applications Nos. 60-2749, 62-62955 (1987), 1-92452 (1989) and 1-201551 (1989). The apparatus of the Publication No. 60-2749 includes a guide nozzle provided between weft measuring and storage device of winding type and main weft picking nozzle and a guide suction tube located on a lateral side of the winding surface of the weft winding and storage device, wherein residual windings of weft on the winding surface are introduced by suction into the guide suction tube and then inserted into the guide nozzle. In the apparatus according to the Publication No. 62-62955, residual windings of weft on the winding surface of weft measuring and storage device are drawn into a suction pipe disposed on a lateral side of the winding surface and retained by suction in the pipe. The weft thus retained is then carried to the inlet of main weft picking nozzle by a weft holding member which is driven to move reciprocally by an air cylinder. EP 0.388.680 is directed to an apparatus that includes a nozzle device for threading the weft yarn into the weft length measuring and storing apparatus. A suction pipe and a cutter for removing and cutting weft yarns are arranged between a weft length measuring and storing apparatus and the main picking nozzle of a air jet loom. The apparatus disclosed by the Publication No. 1-92452 includes a weft feeding nozzle located between weft measuring and storage device of winding type and main weft picking nozzle and a guide pipe provided between the weft measuring and storage device and the weft feeding nozzle. The guide pipe is movable between its guiding and retracted positions and the leading end of a weft is blown from the weft winding tube of the weft measuring and storage device into the guide pipe which is then located in the guiding position. If the weft winding surface of the weft measuring and storage device has thereon residual windings of weft, the weft is pulled back from the weft measuring and storage device by a weft removing means provided upstream of the measuring and storage device while rotating the weft winding tube in reverse direction. The weft thus pulled back is cut at a predetermined position and then blown again into the weft winding tube, from where the leading end of the weft is blown into the guide pipe then located in its guiding position. In the apparatus of the Publication No. 1-201551, there is provided a weft guide between the weft measuring and storage device and the main weft picking nozzle. The weft guide is switchably movable between the weft guiding position for normal weaving operation of the loom and the weft threading position, and the leading end of a new weft passed through the weft guide is blown into the main weft picking nozzle by air jet of the weft guide. In apparatus of the Publication No. 60-2749, wherein the suction guide tube must be moved close to the weft winding surface for removing residual windings of weft on the winding surface, it is difficult for the suction of the guide tube to ensure successful removal of the residual weft on the winding surface. Furthermore, because the residual windings of weft are inserted as they are into the guide nozzle, there is a fear that weft injected from the guide nozzle is directed toward the main weft picking nozzle in an entangled state, thereby inviting a failure in threading the main picking nozzle with the weft. The same difficulty in removing the residual weft holds true for the apparatus of the Publication No. 62-62955. Additionally, provision of the weft holding member which is moved linearly between a position adjacent to the weft measuring and storage device and the inlet of the main weft picking nozzle makes the threading mechanism large in size. In the apparatus of the Publication No. 1-92452, wherein residual windings of weft must be pulled back if the leading of the weft is put into the weft feeding nozzle in the even of a failure in weft threading, the weft handling is time consuming The threading method in this apparatus by which a weft unwound from the weft measuring and storage device is again fed thereto tends to invite a failure in weft handling. Furthermore, provision of the weft removing means on upstream side of the measuring and storage device makes the apparatus complicated in structure. In the apparatus of the Publication No. 1-201551, there is a fear that the leading end of weft inserted into the weft guide may be entangled, so that the weft is fed out from the weft guide in a folded state. It is difficult for such a folded weft, particularly a weft with a thick count or a hard and hence less flexible weft, to be inserted successfully into the inlet of the main weft picking nozzle. Therefore, an object of the present invention is to provide a weft handling apparatus which can avoid complication of the apparatus, prolonged time for weft handling and failure in weft threading. To achieve the above object, the present invention provides a weft handling apparatus in a jet loom which comprises nozzle means disposed downstream of said weft measuring and storage device and upstream of said main picking nozzle, in a passage definded by the weft for guiding the weft therethrough and inserting the same weft through said jet; means disposed adjacent to the inlet of said nozzle means for pneumatically retaining part of the weft, said retaining means having a weft inlet port opended toward said weft measuring and storage device and a weft discarding passage ; means disposed adjacent to said weft measuring and storage device for transferring the weft from said weft measuring and storage device to said weft inlet port of said retaining means by the action of an air flow; means for cutting the weft at a predetermined position in said weft discarding passage of said weft retaining means, while said part of the weft is being retained by said retaining means; and weft end transferring means incorporated in disposed between said retaining means for guiding and presenting the weft end cut by said cutting means in said weft discarding passage to the region of suction adjacent to the inlet of said nozzle means. In the event that a weft break occurs between the weft measuring and storage device and the main weft picking nozzle, the weft retaining means and the weft transferring means are operated to transfer the residual windings of weft on weft winding surface of the weft measuring and storage device to the weft retaining means which then retains the weft. The weft thus being retained is cut by the weft cutting means at a predetermirled position to have a weft of a given length. The cut end of the weft is brought to a position adjacent to the inlet of a weft injection nozzle by transferring movement of the weft end transferring means and then introduced into the weft injection nozzle by suction developed at the inlet by air injection from the injection nozzle. Figs. 1 through 15 show an embodiment of weft handling apparatus in a jet loom according to the present invention and details thereof. Fig. 1 is a side view partially in section showing normal condition of weft feeding through the apparatus during weaving operation of the loom; Fig. 2 is a plan view partially in section showing the same condition as illustrated in Fig. 1; Fig. 3 is a cross-section taken along line A-A of Fig. 2; Fig. 4 is a side view partially in section showing a condition in which a weft is retained after the occurrence of a weft break between time main weft piclcing nozzle and the guide nozzle; Fig. 5 is a side view partially in section showing a condition in which a weft is retained after the occurrence of a weft break between the weft measuring and storage device and the guide nozzle; Fig. 6 is a side view partially in section showing a condition in which a residual weft is introduced into the discarding pipe; Fig. 7 is a side view partially in section showing a condition in which the rotor is being rotated; Fig. 8 8 is a side view partially in section showing a condition in which the rotor has been rotated to the position for presenting a cut weft end to the guide nozzle; Fig. 9 is a side view partially in section showing a condition in which tne rotor has been returned to its original position; Fig. 10 is a side view partially in section showing a condition in which the cut weft end has moved past the paired rollers; Fig. 11 is a side view partially in section showing a condition in which a weft is retained after the occurrence of a weft break between the weft cheese and the weft measuring and storage device; Fig. 12 is a side view partially in section showing a condition in which a residual weft has been discarded into the trash box; Fig. 13 is a plan view partially in section showing a condition in which the leading end of a weft has been removed from the cheese; Fig. 14 is an electrical block diagram showing the computer control and its associated charts; Figs. 15 (a) through (c) are flow charts showing the control program for handling a weft according to the invention; Figs. 16 and 17 are side views partially in section showing modified embodiments of the present invention, respectively; Fig. 18 is a cross-section taken along line B-B of Fig. 17; Figs. 19 and 20 are side views partially in section showing a further modified embodiment of the present invention. Weft measuring and storage device 8; Weft transferring means including weft winding tube 8a and blow nozzle 12; Weft retaining means including nozzle block 15 and blow nozzles 20A, 20B, 21A; Weft end transferring means including rotor 17; Weft cutting means including cutter 22. The following will describe an embodiment of the weft handling apparatus according to the present invention with reference to accompanying drawings including Figs. 1 through 15. There is provided a rotatably bracket 1 (Fig. 1, Fig. 2), which carries at one end thereof a weft cheese 3 and has at the opposite end a weft unwinding motor 2 operatively connected to the bracket 1 through gears for driving the weft cheese 3 to rotate in its unwinding or weft releasing direction. A motor 4 is disposed adjacent to the periphery of the weft cheese 3 on its large-diameter side. The motor 4 is operatively connected to a support arm 5 which supports thereon a weft releasing blow nozzle 6 and a sensor 7 of photoelectric transmission type for detecting the current wound diameter of the weft cheese 3. Supply of air under pressure to the blow nozzle 6 is controlled by a solenoid-operated two-way valve V1, and an air jet injected from the blow nozzle 6 sweeps the cheese peripheral surface from its large-diameter side toward the opposite small-diameter side. A weft measuring and storage device 8 of a known wind ing type is arranged downstream of the weft cheese 3 in respect of the direction in which the weft is fed in the apparatus. The weft measuring and storage device 8 has a weft winding tube 8a driven to rotate by a motor M (indicated in Fig. 14) for winding a predetermined length of reserve weft on weft winding surface 8a of the measuring and storage device 8. The motor M is operable independently of a main loom drive motor (not shown). The windings of reserve weft stored on the weft winding surface 8b can be released when a stop pin 9a, whose reciprocating motion is controlled by an electromagnetic solenoid 9, is moved out of engagement with the weft winding surface 8b. The weft measuring and storage device 8 has further a weft inlet 8c which is in communication with the weft winding tube 8a, and a weft introducing duct 10 is mounted to the device 9 so as to enclose the weft inlet 8c. A weft-break sensor 11 of photoelectric transmission type is provided within the weft introducing duct 10 adjacently to its inlet. A blow nozzle 12 is connected to the weft introducing duct 10 so as to direct an air jet therefrom toward the weft inlet 8c. Supply of air under pressure to the blow nozzle 12 is controlled by a solenoid-operated two-way valve V2. Air jet from the blow nozzle 12 passes through the weft inlet 8c and weft winding tube 8a and directed toward a main weft picking nozzle 13 which is fixedly mounted on a slay (not shown) of the loom. A cone-shaped convergent guide conduit 14 is disposed between the weft cheese 3 and the weft measuring and storage device 8. Substantially all air flow from the weft releasing blow nozzle 6 collected by this guide conduit 14 can be introduced into the duct 10. On the downstream side of the weft measuring and storage device 8 are disposed a nozzle block 15 and a weft guide nozzle 16 connected rigidly to the block. The nozzle block 15 and weft guide nozzle 16 are located so as to receive a weft yarn Y which has been released from the weft winding surface 8b and also to guide the same weft therethrough toward the inlet of the main weft picking nozzle 13. The weft guide nozzle 16 is directed toward the inlet of the main weft picking nozzle 13 moved to its most retracted position as indicated by phantom line in Fig. 2. The nozzle block 15 is formed therein with a weft inlet port 15a, a weft exit passage 15b and a weft discarding passage 15c, and has incorporated therein a weft transferring rotor 17 rotatable to open and close the weft inlet port 15a, exit passage 15b and discarding passage 15c. The rotor 17 is rotatable about an axis extending to intersect perpendicularly with an imaginary line extending through the axial centers of the weft inlet port 15a and weft exit passage 15b in the rotor. The rotor 17 further has forrned therein a passage 17a through which the weft inlet port 15a, weft exit passage 15b and weft discarding passage 15c are normally made to communicate each other. The weft transferring rotor 17 is formed on its periphery with weft receiving recesses or grooves 17b, 17c in communication with the passage 17a. An injection passage 17d is formed in the rotor 17 between the groove 17b and the passage 17a. The rotor 17 is normally positioned as shown in Fig. 1 wherein the weft inlet port 15a, weft exit passage 15b and weft discarding passage 15c are made in communication with each other via the passage 17a in the rotor. The nozzle block 15 has at its top a blow nozzle 20A connected thereto for directing air jet toward the weft discarding passage 15c through the injection passage 17d in the rotor 17 and at a position immediately below the weft inlet port 15a another blow nozzle 20B for directing air jet toward weft discarding port 15c1 at the downstream end of the weft discarding passage 15c. Supply of air under pressure to these blow nozzles 20A, 20B is controlled by a solenoid-operated two-way valve V3. A weft discarding pipe 18 is connected to the weft discarding port 15c1 and extends to a trash box 19. The weft discarding pipe 18 has a bent portion to which a blow nozzle 21A is connected so as to direct its air jet toward the trash box 19. The weft inlet port 15a of the nozzle block 15 is tapered toward the passage 17a of the rotor 17, and the end of the weft winding tube 8a of the weft measuring and storage device 8 is bent to direct air flow from the tube 8a toward the weft inlet port 15a. The weft guide nozzle 16 is connected to the downstream end of the nozzle block 15 with a small space formed therebetween. The space is convergent toward the guide nozzle 16 and communicates with the weft exit passage 15b and the guide nozzle 16. A blow nozzle 21B is connected to the space for communication therewith. Supply of air under pressure to the blow nozzles 21A and 21B is controlled by a solenoid-operated two-way valve V4. As shown most clearly in Fig. 3, an air-operated cylinder 23 is located below the nozzle block 15. The air cylinder 23 has a toothed rack 38 attached to the end of a piston rod extending from the cylinder and the rotor 17 has a pinion 39 engaged with the rack 38 so that extension and retraction of the air cylinder 23 causes the rotor 17 to rotate in alternate directions in the nozzle block 15. Supply of air under pressure to the air cylinder 23 is controlled by a solenoid-operated three-way valve V6. The piston rod of the air cylinder 23 carries a weft clamp 40. The extension of the air cylinder 23 causes the weft clamp 40 to move into the weft discarding passage 15c to be pressed against the interior wall of the passage 15c. A spring 40a is provided to press the weft clamp 40 resiliently against the wall. A weft cutter 22 is fixed at the bent portion of the weft discarding passage 15c between the rotor 17 and the weft clamp 40. The main weft picking nozzle 13 has a weft-break sensor 24 (Fig. 2) of photoelectric transmission type in the inlet thereof and a stationary cutter 13a on top of the opposite exit end thereof. A blow nozzle 25 and a weft introducing duct 26 are disposed immediately above and below the region of air jet from the main weft picking nozzle 13, respectively, in facing relation to each other. An air guide 27 is located adjacently to the exit of the air duct 26 and a weft sensor 28 of photoelectric transmission type is provided within this air guide. A suction pipe 29 having a bent portion, as shown by phantom line in Fig. 2, is provided adjacently to the exit of the air guide 27 and a blow nozzle 30 is connected to the bent portion of the suction pipe 29 for producing air jet toward a trash box (not shown). The main weft picking nozzle 13, blow nozzle 25, weft introducing duct 26, air guide 27 and suction pipe 29 are all mounted on a slay of the weaving loom for movement therewith. Behind the swinging area of these parts 13, 25, 26, 27, 29 are provided a motor 31 and an air cylinder 33. A drive roller 32 is operatively connected to the motor 31 to be driven thereby while a follower roller 34 is mounted to the air cylinder 30 so that extending motion of the cylinder causes the follower roller 34 to be brought into contact engagement with its associated drive roller 32 in the region between the weft introducing duct 26 and the air guide 27. Supply of air under pressure to the main weft picking nozzle 13 and blow nozzle 25, 30 is controlled by solenoid-operated two-way valves V7, V8 and V9, respectively. Supply of air under pressure to the air cylinder 33 is controlled by a solenoid-operated three-way valve V10. As indicated in Fig. 14, operation of the solenoid-operated valves V1 - V4, V6 - V10, motors 2, 4, 31, M, and solenoid 9 are all controlled by a computer control C which is provided independently of a main control apparatus for the weaving loom. The control C is adapted to control the operation of the solenoids and motors from signals which are transmitted from the weft-break sensors 11, 24, weft sensor 28, and cheese wound diameter sensor 7. Diagrams (a) through (c) of Fig. 15 show flow charts of control program for handling a weft in the event of occurrence of a weft break at any position between the weft supply cheese 3 and the main weft picking nozzle 13. The following will describe the operation of the above-described apparatus with reference to the flow charts, as well as to the drawings. Figs. 1 and 2 show a state wherein a weft yarn Y is being fed along its normal path of movement during weaving operation of the loom. If a break has occurred in the weft Y at any position on the weft path between the cheese 3 and the main weft picking nozzle 13, this break is detected by the weft-break sensor 11 or 24, which then transmits to the computer control C a signal representative of a failure in weft feeding. In response to this signal, the control C commands a loom stop to the loom's control unit, which then causes the loom to stop its weaving operation with the main picking nozzle 13 on the slay positioned adjacent to the cloth fell of woven fabric. After the loom has been stopped, it is then rotated reverse for a predetermined amount thereby to swing the weft picking nozzle 13 to its most retracted position (or threading position) as indicated by phantom line in Fig. 2. After such a reverse rotation of the loom, the control C causes the solenoid for valve V3 and also the solenoid 9 to be energized (or turned on) thereby to open the blow nozzles 20A, 20B and to move the stop pin 9a away from the weft winding surface 8b. If the above break has occurred in the weft Y between the weft measuring and storage device 8 and the main weft picking nozzle 13, as indicated by phantom line in Fig. 4 or Fig. 5, the control C responding to a signal from the weftbreak sensor 11, or a signal representative of presence of weft in the weft introducing duct 10, energizes the solenoid for valve V2 for a predetermined period of time to open the blow nozzle 12 for the same predetermined time period. In the event that the weft break has occurred specifically between the weft guide nozzle 16 and the main weft picking nozzle 13, as indicated in Fig. 4, the leading end portion of the weft Y is blown into the weft discarding passage 15c and further into the weft discarding pipe 18, as shown by solid line, by air jet from the blow nozzles 20A, 20B. With the stop pin 9a positioned away from engagement with the weft winding surface 8b and the blow nozzle 12 opened for the above predetermined time period, windings of weft Y1 on the winding surface 8b are released therefrom and blown into the nozzle block 15 by air jet frorn the blow nozzle 12. Thus, the weft Y1 on the weft winding surface 8b is transferred to the region of the weft discarding pipe 18. In the event that the weft break has occurred between the weft measuring and storage device 8 and the weft guide nozzle 16, as indicated by phantom line in Fig. 5, the windings of weft Y1 on the weft winding surface 8b are released therefrom by air jet from the blow nozzle 12 and then transferred to the region of the weft discarding pipe 18 by air jets from the blow nozzles 20A, 20B. In either case of the above weft breaks in Fig. 4 and Fig. 5, part of the weft Y1 is discharged into the trash box 19 through the weft discarding pipe 18, while other part the weft Y1 then extending from the weft winding tube 8a is retained in the weft discarding pipe 18 under the influence of air jets from the blow nozzles 20A, 20B. When the blow nozzle 12 completes air injection for the above predetermined time period, the control C deenergizes (or turns off) the solenoid 9, thereby moving the stop pin 9a into engagement with the weft winding surface 8b. The control C then causes the motor M to be rotated for a predetermined amount, rotating the weft winding tube 8a for a predetermined number of turns thereby to form a reserve weft Y3 with a predetermined number of windings round the weft winding surface 8b, as shown in Fig. 6. After such reserve weft winding, the control C deener-gizes the solenoid for valve V3 and simultaneously energizes the solenoid for valve V4, thereby shutting off the air jets from the blow nozzles 20A, 20B and opening the blow nozzles 21A, 21B. Thus, retaining of the weft Y1 in the pipe 18 by air jet is transferred from the blow nozzles 20A, 20B to the blow nozzle 21A, and a suction is produced in the weft exit passage 15b of the nozzle block 15 by air jet from the blow nozzle 21B. After injection of air jets from the blow nozzles 21A, 21B, the solenoid for valve V6 is energized for a predetermined period of time to actuate the weft clamp 40 for holding the weft Y1 in the weft discarding passage 15c and also to rotate the rotor 17 for a predetermined amount in counterclockwise direction from the position shown in Fig. 6. Incidentally, Fig. 7 shows the rotor 17 on its way of rotation. Portion of the weft Y1 passed through the rotor 17 is pulled by rotation of the rotor 17 toward the weft exit passage 15b. The weft Y1, which is moved into the weft receiving grooves 17b, 17c during the rotation of the rotor 17, will not be nipped by and between the rotor 17 and the nozzle block 15. The portion of the weft Y1 in the weft discarding passage 15c between the weft clamp 40 and the rotor 17 is tensioned while the latter is rotated, so that the weft Y1 is placed in pressing contact with the cutter 22, as shown in Fig. 7, which then cuts the weft. The weft end Y21 cut off from the weft Y1 is brought adjacent to the weft exit passage 15b in a bent state by the rotor 17, as shown in Fig. 8, where the cut end Y21 is introduced into the weft exit passage 15b by suction. It is noted that weft exit passage 15b is smaller in diameter than the weft guide nozzle 16 and, therefore, it is difficult for a weft end in a bent state to be inserted into such weft exit passage 15b unless the weft end is positioned in the region of suction adjacent to the passage. Apparently it becomes more difficult to insert the end when handling a weft which is larger in diameter or less flexible in quality. For threading such a passage with a weft successfully, it is necessary for the weft end to be brought very close to the inlet of the passage where the weft end is subjected to suction which pulls the end into the passage. In this embodiment of the invention, this is accomplished by cutting the weft Y1 at a predetermined position defined by the cutter 22 so that the weft end Y21 is presented to the inlet opening of the weft exit passage 15b where suction is produced by air flow through the passage. Thus, the cut end Y21 of weft can be inserted into the weft exit passage 15b as shown in Fig. 8. The solenoid for valve V6, after being energized for the predetermined time period, is deenergized to retract the weft clamp 40 from the weft discarding passage 15c and the rotor 17 to rotate reverse in clockwise direction to its original position. Thus, the weft portion Y1 cut off from the weft Y2 is released from the weft clamp 40 and discharged into the trash box 19. On the other hand, the weft Y2 having its cut end Y21 introduced into the weft exit passage 15b of the nozzle block 15 is pulled into the guide nozzle 16 by suction while the rotor 17 is rotated reverse. Thus, threading the guide nozzle 16 with weft Y2, or insertion of the weft through the guide nozzle, is completed as shown in Fig. 9. After the rotor 17 has returned to its original position, the solenoid 9 is energized, moving the stop pin 9a away from the weft winding surface 8b. Then, the solenoids for valves V7, V8, V9 are energized to activate the main weft picking nozzle 13 and the blow nozzles 25, 30, respectively, so that air flow is produced which is directed from the blow nozzle 25 toward the inlet 26a of the weft introducing duct 26, moving across an air jet then issued from the main weft picking nozzle 13. Simultaneously, air flow is generated in the suction pipe 29, developing vacuum in the same pipe. The weft Y2 in the guide nozzle 16 is blown into the main picking nozzle 13 while pulling the reserve windings of weft Y3 from the weft winding surface 8b with the aid of air jet from the guide nozzle 16. The weft Y2 blown into the weft picking nozzle 13 is flown out therefrom. The air jet from the picking nozzle 13 meets with the air jet from the blow nozzle 25 and is diverted into the weft introducing duct 26, so the leading end of the weft Y2 coming out from the picking nozzle 13 is deflected to enter into the duct 26 without being picked into a shed. The leading end of the weft Y2 subjected to the air jet from the blow nozzle 25 is moved past the region between the paired rollers 32, 34 and reaches the weft sensor 28. If the control C fails to receive a weft-detected signal from the sensor 28 in a predetermined period of time, the control deenergizes the solenoids for valves V4, V7, V8, V9 and the solenoid 9, shutting off the air jets from the blow nozzles 21A, 21B, weft picking nozzle 13, blow nozzles 25, 30 and also moving the stop pin 9a into engagement with the weft winding surface 8b, with simultaneous alarming by an alarm device 35 (Fig. 14). When the control C receives a weft-detected signal from the sensor 28 in the predetermined period of time, the control responding to that signal deenergizes the solenoids for valves V4, V7, V8 and also the solenoid 9, thereby stopping air injection from the guide nozzle 16, main weft picking nozzle 13 and blow nozzle 25 and moving the stop pin 9a into engagement with the weft winding surface 8b. In turn, the control C energizes the solenoid for valve V10 to actuate the cylinder 33 in extending direction, which causes the follower roller 34 to be brought into contact engagement with its associated drive roller 32 thereby nipping the weft Y2 there between as shown in Fig. 10. Subsequently, the control C activates the motor M to rotate the weft winding tube 8a for a predetermined number of turns for forming reserve windings of weft on the weft winding surface 8b. After this reserve weft winding, the control C activates the motor 31 to rotate the roller 32. The weft Y2 is pulled by the paired rollers 32, 34. The weft tensioned by such pulling is cut by the stationary cutter 13 on the main weft nicking nozzle 13. The end portion cut off the weft Y2 is pulled by the rollers 32, 34 and discarded by the blow nozzle 30 into a trash box (not shown). When the entire cut weft end weft has noved past the air guide 27, a signal is generated by the sensor 28 which is representative of no weft being detected. In response to this signal, the control C causes the motor 31 to be stopped and the solenoids for valves V10, V9 to be deenergized, so the air cylinder 33 is operated in its retracting direction to move the roller 34 away from its associated roller 32 and the blow nozzle 30 is closed. Thereafter, the loom is resumed to its starting position ready for its weaving operation. If a weft break has occurred between the weft cheese 3 and the measuring and storage device 8, as shown in Fig. 11, the control C responds to a no-weft-detected signal from the weft-break sensor 11 and, in response thereto, commands a loom stop to the loom's control unit which in response thereto causes the loom to stop its operation and then to rotate reverse for a predetermined amount. Upon such reverse rotation of the loom, the control C turns on the solenoids for valves V3 and the solenoid 9, and energizes the solenoid for valve V2 for a predetermined period of time, in the same manner as in the above-described previous cases. By so doing, the weft including the windings of weft on the weft winding surface 8b is discharged into the trash box 19, as shown in Fig. 12. Thereafter, the control C executes a control program different from that executed for the previous cases. After the solenoid for valve V2 has been energized for the above time period, the control C responds to information on the current wound diameter of the cheese 3 which is detected by the sensor 7 and operates the motor 4 accordingly so as to move the weft releasing nozzle 6 to a position spaced from the periphery of the cheese 3 at a distance suitable for weft releasing from the cheese 3. Then, the control C energizes the solenoids for valves V1, V2 to open the blow nozzles 6, 12, respectively. Subsequently, the control C activates the motor 2. Thus, the weft cheese 3 is rotated in weft releasing direction while being subjected to air jet from the blow nozzle 6, so that the leading end Y4 of weft on the cheese 3 is removed from its periphery and blown into the convergent guide conduit 14 by air jet issued from the blow nozzle 6. Air jet from the blow nozzle 6 is directed toward the inlet of the introducing duct 10 by the air collecting action of the air guide conduit 14, so that the weft leading end Y4 is guided and introduced into the duct 10, as shown in Fig. 13. The weft end Y4 is blown out of the weft winding tube 8a by air jet from the blow nozzle 12 and then transferred to the weft discarding pipe 18 and retained there by air jets from the blow nozzles 20A, 20B. If the control C fails to receive a weft-detected signal from the weft-break sensor 11 in a predetermined period of time after the weft leading end Y4 has been removed from the weft cheese 3, the control C causes the solenoid 9 to be deenergized the motor 2 to be stopped and the solenoids for valves V1, V2, V3, to be deenergized. Simultaneuosly the alarm device 35 is actuated for alarming. When the control C receives the weft-detected signal from the sensor 11 in the above time period, the control C causes the solenoid 9 to be deenergized to move the stop pin 9a into engagement with the weft winding surface 8b, the motor 2 to be stopped, and the solenoids for valves V1, V2 to be deenergized to close the blow nozzles 6, 12. Then, the motor M is driven to rotate for a predetermined amount to form reserve windings of weft on the weft winding surface 8b. Thereafter, the same steps as those described with reference to the previous cases are performed for the operations subsequent to formation of reserve windings of weft. As it is apparent from the foregoing, it is essential that the weft should be inserted into the guide nozzle 16 for successfully threading the main weft picking nozzle 13. It is practically impossible, however, to insert the leading end of the weft directly into the guide nozzle 16 only by the aid of air jet from the weft winding tube 8a. For successful threading, it is necessary to present the leading end of the weft to the inlet of the guide nozzle 16. This can be made possible by cutting the weft beforehand at a predetermined position upstream of the guide nozzle. In the above-described embodiment, the weft is cut at a predetermined position by rotation of the rotor 17 thereby to form a cut end and this weft end is brought to the region of suction of the guide nozzle 16. Thus, the apparatus of this embodiment, in which the weft is passed through the guide nozzle 16 with its cut end inserted thereinto first, can handle successfully even a thick or less flexible weft. According to the above embodiment of the invention, no matter where a weft break takes place, the resulting residual windings of weft on the weft winding surface 8b can be discarded through the weft discarding passage 15c and pipe 18. That is, discarding of residual windings of weft can be accomplished by a series of the same operations which include air blowing by the blow nozzles 20A, 20B, 21A, releasing the stop pin 9a from the weft winding surface 8b, and air blowing by the blow nozzle 12 for a predetermined period of time to transfer the weft to the region of air blowing by the nozzles 20A, 20B for retaining the weft in that region. Thus, the control program to be executed for disposing of the residual windings of weft in the event of a weft break can be simplified in comparison with such programs that are designed to handle the weft in a different way for each different condition of weft break and, therefore, weft sensors which are required for different conditions of weft break become unnecessary. It is to be understood that the present invention is not limited to the above-described embodiment, but it may be practiced in other various ways, as exemplified below. Referring to a modified embodiment shown in Fig. 16, there is provided a rotor 36 rotatable in alternate directions in the nozzle block 15 by reciprocal movement of the toothed rack 38. This rotor 36 has a pair of pins 36a imnlanted in the periphery thereof. Weft receiving grooves 17e are formed in the inner periphery of the nozzle block 15 along the inoving path of the paired pins 36a of tl-1e rotor 36. In this embodiment, the cut end of a weft can be presented properly to the inlet of the weft exit passage 15b by rotation of the rotor 36. Referring to Figs. 17 and 18 showing another embodiment of the invention, the nozzle block 15 is disposed adjacently to the main weft picking nozzle 13 in its fully retracted position so that a weft is inserted from the nozzle block 15 directly into the main picking nozzle 13. The nozzle block 15 in this embodiment is formed on its lateral side with a slit opening 15d for receiving thereinto a weft swinging between the main picking nozzle 13 and the nozzle block 15. Thus feeding of a weft from the nozzle block 15 to the main picking nozzle 13 for both threading and picking can be performed. Figs. 19 and 20 show still another embodiment of the present invention, wherein the cut end of weft is presented to the suction at the inlet of the weft exit passage 15b by means of a linearly movable rod 37. The rod 37 is moved together with the weft clamp 40 to their operative positions shown in Fig. 20 by the cylinder 23, and the rod is formed with a weft receiving groove 37a. Fig. 19 shows a state where the weft Y1 extends through the nozzle block 15 into the weft discarding pipe 18 and retained in the pipe by air jet. As the air cylinder 23 is actuated to extend, moving the rod 37 and the weft clamp 40 to their operative positions, the weft Y1 is clamped by the weft clamp 40 and pulled by the rod 37. Thus, the weft Y1 is cut at a predetermined position by the cutter 22 and the cut end of the weft is presented precisely to the inlet of the weft exit passage 15b. The weft yarn handling apparatus for a jet looms includes means 8a for unwinding the weft from a weft supply cheese 3. The length of the unwound weft yarn Y is measured and the yarn is stored on a drum 8b of the measuring and storing device 8 The weft Y thus measured and reserved is then transferred to the main nozzle 13 of an air jet loom and then inserted through the shed by fluid injected from the main picking nozzle 13. On the downtream side of the weft measuring and storage device 8 there is a nozzle block arrangement 15; 12, 8a, 15a, 15b, 16 for transferring weft yarn from the measuring and storage device 8 to the main nozzle 13 and in addition means 40 for retaining weft yarn in the case of a weft yarn break. The nozzle block further includes means 22 for cutting the weft Y at a predetermined position while said part of the weft Y is being retained by said retaining means 40. One cut end of weft yarn Y is blown or sucked to a trash box 19 and the other end is guided to the region of suction adjacent to the inlet of weft injection main nozzle 13. The arrangement is operated automatically by a control C, that starts operating when a weft yarn break is detected that required threading of the main nozzle 13. The arrangment provides for a non complicated, fast threading of the main nozzle 13 and low failure rate. In the weft handling apparatus of the invention wherein a weft is cut at a predetermined position and the cut end of the weft is brought and presented to the region of suction adjacent to the inlet of a weft injection nozzle by weft end transferring means such as the rotor, insertion of a weft into the injection nozzle can be performed with a higher degree of success without making the apparatus large in size.

Claims: A weft yarn handling apparatus in a jet loom wherein a length of weft unwound from a weft supply cheese (3) is measured and reserved by a weft measuring and storage device (8) of winding type and the weft (Y) thus measured and reserved is then inserted through a shed by fluid injected from a main picking nozzle (13), said weft handling apparatus characterized by: nozzle means (16) disposed downstream of said weft measuring and storage device (8) and upstream of said main picking nozzle (13), in a passage definded by the weft (Y) for guiding the weft therethrough and inserting the same weft through said jet; means (15, 20A, 20B) disposed adjacent to the inlet of said nozzle means (16) for pneumatically retaining part of the weft (Y), said retaining means having a weft inlet port (15a) opended toward said weft measuring and storage device (8) and a weft discarding passage (15c); means (12, 8a) disposed adjacent to said weft measuring and storage device (8) for transferring the weft (Y) from said weft measuring and storage device (8) to said weft inlet port (15a) of said retaining means (15, 20A, 20B) by the action of an air flow; means (22) for cutting the weft (Y) at a predetermined position in said weft discarding passage (15c) of said weft retaining means (15, 20A, 20B), while said part of the weft is being retained by said retaining means ; and weft end transferring means (17) incorporated in said retaining means (15, 20A, 20B) for guiding and presenting the weft end cut by said cutting means (22) in said weft discarding passage (15c) to the region of suction adjacent to the inlet of said nozzle means (16). A weft handling apparatus as claimed in claim 1 with futher means (13a) for cutting the weft yarn (Y) and being disposed downstream the main picking nozzle (13). A weft handling apparatus as claimed in claim 1 or claim 2, furth comprising means (25, 26, 31, 32, 33, 34, 27, 29, 30) for removing weft yarn (Y) from the weft yarn path and being disposed downstream the main picking nozzle (13). A weft handling apparatus as claimed in any of claims 1 to 3, said weft end transferring means (17) including rotable guiding means for changing the path of weft yarn (Y). A weft handling apparatus as claimed in any of claims 1 to 4 further including means (6, 14, 10, 12) for transferring the weft yarn (Y) end from a weft supply cheese (3) to said weft storing and mesuring device (8). A weft handling apparatus as claimed in claim 5, said means for transferring the weft yarn to the weft storing and measuring device further including means (4, 5, 7) for controlling the position of a blow nozzle (6) in relation to the wound diameter of the weft supply cheese (3). An air jet loom comprising a weft handling apparatus as claimed in any of claims 1 to 6.

Inventors: MURATA MASAHIKO, MURATA, MASAHIKO, MURATA, MASAHIKO, C/O KABUSHIKI KAISHA TOYODA
Applicants: TOYODA AUTOMATIC LOOM WORKS, KABUSHIKI KAISHA TOYODA JIDOSHOKKI SEISAKUSHO
Application year: 1991
Main classification: D03D47
IPC codes: D03D47