Weft processing apparatus in a jet loom

Abstract: The invention relates to a weft processing apparatus comprising a weft releasing device for releasing or detaching a leading end of a weft (Y₂) from the peripheral surface of a weft cheese (10B), a fluid jetting device for moving the released weft leading end to a weft introducing port (20a) of a weft length-measuring and reserving apparatus (22), and a guide device (17) for guiding the weft leading end (Y₂) and the jetted fluid stream. The weft releasing device is in the form of a blow nozzle device (18) or a suction pipe (13). In the former case, the blow nozzle device (18) serves also as the fluid jetting device. The suction pipe (13) has an intake port provided with a holding member such as a net (13a) or brush for temporarily holding the weft in a congregated state.

Description: The present invention relates to a weft processing apparatus for guiding the leading end of a weft fed from a weft supply source in the form of a cheese to a weft winding type weft length-sizing and reserving apparatus when a weft feed failure such as breakage of the weft occurs between the weft cheese and the weft length-measuring and reserving apparatus or when a weft of a new cheese is to be used upon exhaustion of the weft cheese used till then. Prior Art A weft processing apparatus of the type mentioned above is disclosed, for example, in Japanese Laid-Open Patent Application No. 264949/1988 (JP-A-63-264949). In the disclosed apparatus, a suction guide tube of a conical configuration is set at a suction position in the vicinity of the peripheral surface of a weft cheese for drawing out by suction the leading end of a weft from the weft cheese and is then displaced to a stand-by position far away from the weft cheese, wherein the leading end of the weft being held under suction is inserted into an introducing port of the winding type weft length-measuring and reserving apparatus. The leading end of the weft sucked by the suction guide tube and positioned at the introducing port is then inserted into the introducing port under the sucking action thereof to be thereby threaded into and through the weft length-measuring and reserving apparatus. In this manner, the suction guide tube is changed over between the sucking position where it encloses the weft cheese and the stand-by position far away from the weft cheese. Since the prior art apparatus is of such a structure that the drawing-out of the leading end of the weft from the cheese and the introduction of the weft drawn out to the introducing port of the weft length-measuring and reserving apparatus are performed by using one and the same suction guide tube, the latter is restricted in respect to the congfiguration, size and the location for installation and thus suffers from a problem that the freedom in design is seriously limited. For example, the sucking position of the suction guide tube has to be set so as to match with the full bobbin weft cheese. Consequently, when failure occurs in the course of feeding a weft under the condition that the diameter of the weft cheese has been decreased smaller than that of the full bobbin cheese, the sucking position of the suction guide tube will be no more optimal for the weft cheese of concern. As a result, the sucking action of the suction guide tube becomes lowered particularly when the weft cheese has been reduced in the diameter, giving rise to the unwanted possibility that the drawing-out of the leading end of the weft from the weft cheese results in failure. Also, the structure of the apparatus is inevitably much complicated because of necessity for moving the suction guide tube toward the weft length-measuring and reserving apparatus in order to introduce the weft leading end into the introducing port of the weft length-measuring and reserving apparatus. Further, it is noted that the leading end of the weft sucked by the suction guide tube lies in a linear form. In this conjunction, it is clear that the area presented by the weft of a linear form and subjected to the action of a transporting air flow such as the suction or blowing is very small. Consequently, displacement of the linear weft to another place or location under the action of the transporting air flow lacks in reliability. Another prior art that is of interest is US-A-3 868 813. It discloses devices for detaching and winding off the exposed yarn end from a body of wound-up yarn on a bobbin by means of compressed air. It is particularly for use with automatic thread connection devices of ring spinning machines. Each device comprises a holder for a bobbin and a driving device for moving the bobbin to-and-fro in the axial direction relatively to at least three jet nozzles distributed equidistantly round the bobbin. The nozzles are set at an angle of about 45° to the bobbin axis so as to supply jets of compressed air that detach and wind off the yarn end which is received by a reception tube. The bobbin may remain displaced from the reception tube or alternatively the bobbin may be inserted in the tube, in which case the nozzle jets are directed into an annular gap between the bobbin and tube. Alternatively, the nozzles and said tube may move relatively to a stationary bobbin. SUMMARY OF THE INVENTION The general object of the present invention is to provide a weft processing apparatus which can guide the leading end of a weft from a weft supply source to a weft length-measuring and reserving apparatus with a significantly improved reliability. Further, a primary object of the present invention is to provide a weft processing apparatus which is capable of drawing out with a high realiability the leading end of a weft from a weft cheese regardless of its diameter. Another object of the present invention is to provide a weft processing apparatus which is capable of drawing out the leading end of a weft from a weft cheese and transferring it to a weft length-measuring and reserving apparatus by utilizing a transporting or carrier fluid flow. The present invention is as defined in the accompanying claims. According to a general aspect of the present invention, a weft processing apparatus for a jet loom is provided, which comprises means for releasing the leading end of a weft from a peripheral surface of a weft cheese, means for jetting a fluid to move the released leading end of the weft to a weft introducing port of a weft length-measuring and reserving apparatus by the jetted fluid, and means for guiding the travel of the leading end of the weft toward the weft introducing port together with the jetted fluid into the weft introducing port. The leading end of the weft drawn out from the peripheral surface of a weft cheese by the weft releasing means is moved to the weft introducing port of the weft length-measuring and reserving apparatus by the fluid jetting means in cooperation with the guide means to be thereby placed in the weft introducing port. In this way, the drawing-out of the weft from the weft cheese as well as insertion of the weft into the weft introducing port can be accomplished substantially without fail. In a preferred embodiment of the present invention, the weft releasing means is constituted by suction means in the form of a suction pipe through which a suction air flow is generated, wherein the suction pipe has a suction opening or port which is preferably provided with weft holding means such as a net, brush or the like for holding the weft in a congregated state for the purpose of allowing the weft held temporarily in the congregated state to be moved to the introducing port through the medium of a fluid jetted from the fluid jetting means. When the leading end of the weft is to be drawn out from the weft cheese, the weft congregating and holding region of the weft holding means is disposed at a weft receiving position located in the vicinity of the weft cheese so that the leading end of the weft is received by the weft congregating and holding means from the weft cheese. When the weft congregating and holding region of the weft holding means now holding the weft leading end is changed over to a stand-by position, the congregated weft leading end undergoes the transporting action of the fluid jetting means, whereby the weft held in the congregated state at the weft congreating and holding area is moved or carried to the weft introducing port by the jetted fluid. BRIEF DESCRIPTION OF THE DRAWINGS A more detailed understanding of the invention may be had from the following description of preferred embodiments thereof, given by way of example and to be read and understood in conjunction with the accompanying drawings, in which: Fig. 1 is a side elevational view showing, partly in section, how a weft is guided during operation of a jet loom provided with a weft processing apparatus according to an exemplary embodiment of the invention; Fig. 2 is a plan view showing, partly in section, the loom shown in Fig. 1; Fig. 3 is a bottom plan view showing, partly in section, a main portion of the loom shown in Fig. 1; Fig. 4 is a side elevational view for explaining the state in which a suction arm is swung under gravity in the loom shown in Fig. 1; Fig. 5 is a perspective view showing a major portion of the weft processing apparatus according to an embodiment of the invention in the state illustrated in Fig. 4; Fig. 6 is a perspective view showing a major portion of the weft processing apparatus for explaining the state in which the suction arm holding the weft in the congregated state has been restored to a stand-by position in the loom shown in Fig. 1; Fig. 7 is a perspective view showing a major portion of the weft processing apparatus according to the invention in the state where the weft end, which has been held in the congregated state, is being transported along a transporting guide; Fig. 8 is a plan view showing in section the loom of Fig. 1 in the state where the leading end of a weft has been threaded through a weft length-measuring and reserving apparatus; Fig. 9 is a side elevational view showing, partly in section, the loom of Fig. 1 in the state where the leading end of a weft has been threaded to a contacting area between a pair of receiving rollers brought into contact with each other; Fig. 10 is a block diagram for explaining operation of the loom shown in Fig. 1; Figs. 11A to 11D are flow charts for illustrating a weft processing program for the loom shown in Fig. 1; and Fig. 12 is a side elevational view showing, partly in section, another embodiment of the weft processing apparatus according to the invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, there is shown in Figs. 1 to 11 a first embodiment incorporating the present invention. In Figs. 1 to 11, disposed on a lateral side of a frame structure (not shown) of a weaving machine or loom is a weft feeder frame assembly 1 having an upper frame 1a on the top surface of which a supporting shaft 2 is rotatably mounted in an upstanding position. A turn table 3 is supported by the supporting shaft 2 at a top end portion thereof. Mounted on the upper frame 1a at the lower side thereof is an electric motor 4 having an output shaft on which a driving gear 4a is mounted and adapted to mesh with a driven gear 5 which is mounted on the supporting shaft 2 at a bottom end portion thereof. Thus, the turn table 3 can be rotated by energizing the motor 4. A pair of bobbin holding brackets 6 and 7 are rotatably supported on the turn table 3 at angularly symmetrical positions with an angular difference of 180° therebetween. These bobbin holding brackets 6 and 7 have respective lower end portions on which driven gears 6a and 7a are fixedly mounted, respectively. An electric motor 8 is mounted on the top surface of the upper frame 1a of the weft feeder frame assembly 1 and has an output shaft on which a driving gear 8a is mounted at a position lying on a circular path along which the driven gears 6a and 7a are revolved as the turn table 3 is rotated. An air cylinder 9 is mounted on the upper frame 1a in an upstanding position below and within a radial extension of the turn table 3 in such an arrangement in which the tip end of a cylinder rod 9a of the air cylinder 9 can be moved to intersect with or away from the lower surface of the turn table 3. The air cylinder 9 is connected to a pressurized air supply tank (not shown) by way of a three-way type electromagnetic valve V₁. Formed on the lower surface of the turn table 3 are a pair of positioning recesses 3a and 3b at angularly symmetrical positions with an angular difference of 180° therebetween so as to be each engageable with the free end portion of the rod 9a of the air cylinder. In the state in which the rod 9a engages in the positioning recess 3a, the driving gear 8a meshes with the driven gear 6a, while in the state in which the rod 9a engages in the positioning recess 3b, the driving gear 8a meshes with the driven gear 7a. When the electric motor 8 is actuated in the state in which the driving gear 8a meshes with the driven gear 6a, a weft cheese 10A supported on the bobbin holding bracket 6 is caused to rotate, while upon actuation of the motor 8 when the driving gear 8a meshes with the driven gear 7a, a weft cheese 10B supported on the bobbin holding bracket 7 is caused to rotate. Installed at positions in the vicinity of the bobbin holding brackets 6 and 7 are winding diameter sensors 47 and 48, respectively, each of which may be constituted by a reflection type photoelectric sensor, serving to detect the presence or absence of the weft cheeses 10A and 10B on the bobbin holding brackets 6 and 7, respectively. In Fig. 1, a reference numeral 11 denotes a tail holder for holding a trailing end of a weft Y₁ of the weft cheese 10A and a leading end of a weft Y₂ of the weft cheese 10B. A pair of upstanding supporting brackets 1b are disposed at lateral sides of the weft feeder frame assembly 1. Supported between these supporting brackets 1b at free end portions thereof is a suspended suction arm 12 rotatable about a supporting shaft 12a. The suction arm 12 has an end portion located remotely from the supporting shaft 12a which is formed integrally with a weft releasing suction pipe 13 so as to rotate together with the suction arm 12. The rotational radial path or trajectory along which the suction pipe 13 is moved is so established as to intersect with a peripheral surface of the weft cheese (10A in the case of the illustrated embodiment) at the side where the electric motor 8 is located. Mounted at the suction opening of the suction pipe 13 is a net 13a for holding temporarily the weft in a congregated state with a roller 13b being disposed in the vicinity of the net 13a, as can best be seen in Fig. 5. Installed on a bottom frame 1c of the weft frame assembly 1 is a blower 14 to which a base end portion of the suction pipe 13 is connected by way of a hose 15, a dust box 16 and a filter 16a. Also supported on the supporting brackets 1b at the free end portions thereof is a suspended channel-like transporting guide 17 which serves to guide a weft and which extends downwardly to a base end or bottom of the weft cheese at the side where the electric motor 8 is located. A window or notch 17a is formed in the transporting guide 17 at the bottom end portion thereof at a depth reaching the innermost surface of the guide 17 with such a positional relation to the rotational trajectory of the free end portion of the suction pipe 13 and thus the net 13a that the suction pipe 13 can swing into and out of the window 17a. Further, mounted on the transporting guide 17 at the base or bottom end portion is a blow nozzle 18 which serves to move the weft with the aid of air jet. To this end, the blow nozzle 18 is fluidly communicated with the pressurized air supply tank (not shown) by way of a two-way type electromagnetic or solenoid valve V₃. The jet direction of the blow nozzle 18 is oriented along the innermost surface of the transporting guide 17 so that the jet stream from the blow nozzle 18 is directed upwardly along the transporting guide 17. Mounted on the top end portion of the supporting bracket 1b is an air cylinder 19 which has a driving rod 19a connected to the suction arm 12 and which is communicated with the pressurized air supply tank through a three-way solenoid or electromagnetic valve V₂. When the electromagnetic valve V₂ is deenergized, the driving rod 19a projects from the air cylinder 19. As a result, the suction arm 12 is held at a stand-by position shown in Fig. 1. At this stand-by position, the position of the net 13a coincides with that of the window 17a formed in the transporting guide 17. Upon energization of the solenoid valve V₂, the suction arm 12 is swung downwardly about the supporting shaft 12a under the gravity, whereby the roller 13b is brought into contact with the peripheral surface of the weft cheese. Further, for the purpose of guiding the weft, a weft insertion guide 20 is horizontally disposed above the weft feeder frame assembly 1 in such an orientation as to orthogonally intersect with the axis of rotation of the turn table 3. A blow nozzle 21 is disposed at one end portion of the weft inserting guide 20 and is communicated with the pressurized air supply tank through a two-way electromagnetic valve V₄. The weft inserting guide 20 has a bottom surface formed with an introducing or inlet port 20a which is disposed at a position where the axes of the paired bobbin holding brackets 6 and 7 and the axis of rotation of the turn table 3 intersect with one another. The top end of the transporting guide 17 is directed toward the introducing port 20a. Installed immediately before the weft inserting guide 20 is a known winding type weft length-measuring and reserving apparatus generally denoted by 22, which is provided with a weft winding tube 22a adapted to be rotationally driven by a motor M (refer to Fig. 10) provided separately from a loom driving motor (not shown). The weft is delivered from the weft winding tube 22a, as it rotates, to be wound around a weft winding surface 22b. On the other hand, delivery of the weft from the weft winding surface 22b is controlled by a retainer pin 23a which is adapted to be pulled out or in by an electromagnetic coil assembly or solenoid 23. Installed in association with a weft introducing member 22c communicated with the weft winding tube 22a are a weft breakage sensor 24, which may be constituted by a transmission type photoelectric sensor, and a weft inserting blow nozzle 25 which is communicated with the pressurized air supply tank by way of a two-way type electromagnetic valve V₅. The jet stream from the weft inserting blow nozzle 25 is directed from the weft winding tube 22a communicated with the weft introducing member 22c of the weft length-measuring and reserving apparatus 22 toward a weft inserting main nozzle 26. Mounted on a guide duct 27 having a convergent configuration and supporting the electromagnetic solenoid 23 are a plurality of weft removing blow nozzles 28 each adapted to discharge a jet of air oriented towards the weft winding surface 22b. The jet streams from the weft removing blow nozzles 28 sweep the weft winding surface 22b in such a manner that the weft wound on the weft winding surface 22b can be removed therefrom when the retainer pin 23a is positioned away from the weft winding surface 22b. The weft removing blow nozzles 28 are connected to the pressurized air supply tank through respective two-way type electromagnetic valves V₆. Referring to Fig. 2, disposed at a location immediately succeeding to a reduced-diameter opening of the converging guide duct 27 are a blow nozzle 29 and a suction pipe 30 in opposition to each other across the weft path. The blow nozzle 29 is connected to the pressurized air supply tank through a two-way type electromagnetic valve V₇ while the suction pipe 30 is connected to a blower 31. Mounted stationarily at the entrance of the suction pipe 30 is a cutter blade 30a. A weft detector 32 which may be constituted by a transmission type photoelectric sensor is provided within the suction pipe 30. An arm 33 is installed adjacent to the suction pipe 30 in a manner as allowing the arm 33 to be rotated or swung by means of an electric motor 34. A stationary gripper 33a is mounted at the free end of the arm 33. Additionally, a movable gripper 33b is rotatably supported on the free end portion of the arm 33 so as to be brought into contact with the stationary gripper 33a and is operatively connected to an electromagnetic coil or solenoid 35. Both the grippers 33a and 33b are normally in the open state. However, when the electromagnetic solenoid 35 is energized, the path region defined by both the grippers (hereinafter referred to as the weft gripper) intersects with the region defined between the blow nozzle 29 and the suction pipe 30 and is disposed in the vicinity of the entrance 26a of the weft inserting main nozzle 26. A weft breakage sensor 36 comprising a transmission type photoelectric sensor is installed within the entrance 26a of the weft inserting main nozzle 26. Additionally, a stationary blade member or cutter 26b is mounted on the weft inserting main nozzle 26 at the tip end thereof so as to project slightly beyond the latter. A blow nozzle 37 is installed immediately below the weft inserting main nozzle 26 in such an orientation that the jet direction of the former intersects with the path of the jet air stream from the weft inserting main nozzle 26. A weft introducing duct 38 is installed immediately above the weft inserting main nozzle 26 and has an entrance 38a which is positioned opposite to the jet orifice of the blow nozzle 37 across the jet path of the weft inserting main nozzle 26 and an exit 38b which is directed toward the downstream side of the weft inserting main nozzle 26. An air guide 39 is installed downstream of the exit 38b and has a tapered inner passage at which a weft detector 40 constituted by a transmission type photoelectric sensor is mounted. Installed downstream of the air guide 39 is a suction pipe 41 having an exit portion bent toward a dust box (not shown). A blow nozzle 42 is connected to the bent portion of the suction pipe 41 so as to be directed toward the dust box. The weft inserting main nozzle 26, blow nozzle 37, weft introducing duct 38, air guide 39 and suction pipe 41 are all mounted on a slay so as to be movable as a unit, accompanying the swinging movement of the slay. Disposed downstream of the region where the above-mentioned members 26, 37, 38, 39 and 41 are swung is a weft receiving motor 43 to which a driving roller 44 is operatively connected. Installed immediately above the driving roller 44 is an air cylinder 45 having a driving rod on which a driven roller 46 is rotatably suppported in opposition to the driving roller 44 so that the former can be pressed against the latter through the pushing operation of the air cylinder 45. All of the weft inserting main nozzle 26 and the blow nozzles 37, 42 are connected to the pressurized air supply tank through two-way type electromagnetic valves V₈, V₉ and V₁₀, while the air cylinder 45 is connected to the pressurized air supply tank through a three-way type electromagnetic valve V₁₁. As seen in Fig. 10, the individual electromagnetic valves V₁ to V₁₁, the motors 4, 8, 34, 43 and M, the blowers 14 and 31 and the electromagnetic solenoids 23 and 35 are controlled under the command of a control computer C which is provided separately from a loom control computer. The control computer C performs on/off (open/close) control of the electromagnetic valves V₁ to V₁₁ in response to the detection signals generated by the weft breakage sensors 24 and 36, the weft detectors 32 and 40 and the winding diameter sensors 47 and 48 and additionally controls electrical energization and deenergization of the motors 4, 8, 34, 43 and M, the blowers 14 and 31 and the electromagnetic solenoids 23 and 35. Fig. 11A to 11D show flow charts for explaining a weft processing program activated when weft breakage takes place between the weft cheese 10A or 10B and the weft length-measuring and reserving apparatus 22, i.e. when the weft breakage sensor 24 detects the absence of the weft during operation of the loom. The weft processing procedure will be described below by reference to the above-mentioned flow charts. Now, it is assumed that the loom is running and the weft feeding is effectuated from the weft cheese located on the side of the transporting guide 17 (the weft cheese 10A in the case of the illustrated embodiment). The state in which the weft is drawn out from the weft cheese 10A during operation of the loom is shown in Figs. 1 and 2. When the weft cheese 10A becomes empty, this empty state is detected by the winding diameter sensor 47. On the basis of the detection signal from the winding diameter sensor 47, the control computer C commands the opening of the electromagnetic valve V₁, whereby the positioning rod 9a is retracted from the positioning recess 3a. Subsequently, the control computer C issues a command to allow the electric motor 4 to rotate over a predetermined angular distance for rotating the turn table 3 by a half-rotation. In this manner, the weft cheeses 10A and 10B are exchanged with each other, resulting in that the weft cheese 10B is set at a position for allowing the draw-out or delivery of the weft therefrom. Assuming that the weft Y₁ is broken on the weft feeding path between the weft cheese 10A in the weft delivery position and the weft length-measuring and reserving apparatus 22, the weft breakage is detected by the weft breakage sensor 24, as a result of which a weft feed fault signal is supplied to the control computer C. In response to this weft feed fault signal, the control computer C sends a loom operation stop signal to the loom control computer which responds thereto by issuing a loom operation stop command. As a result, the weft inserting main nozzle 26 on the slay is caused to stop at a position in the vicinity of the cloth fell of the fabric being woven. After the loom has been stopped, the loom control computer issues a command for causing the loom frame to rotate reversely for a predetermined angular distance to move the weft inserting main nozzle 26 to the most retracted position (weft threading position) shown in Fig. 8. In succession to the reverse rotation of the loom frame mentioned above, the control computer C issues a command for energization of the electromagnetic solenoid 23 and the opening of the electromagnetic valves V₉ and V₈, whereby the retainer pin 23a is moved away from the weft winding surface 22b while the blower nozzle 37 and the weft inserting main nozzle 26 jet air streams, respectively. When the weft remains wound on the weft winding drum surface 22b, the remaining weft is then ejected from the weft inserting main nozzle 26. However, due to the intensive blow-up action of the blow nozzle 37, the remaining weft is introduced into the weft introducing duct 38 to an extent to reach the position where the weft detector 40 is installed within the air guide 39. The control computer C responds to the weft presence detection signal from the weft detector 40 to issue a command for closing the electromagnetic valves V₈ and V₉ while commanding the opening of the electromagnetic valve V₁₁. Thus, the weft inserting main nozzle 26 and the blow nozzle 37 stop the air jetting operation, while the rollers 44 and 46 are pressed against each other. In this manner, the weft introduced into the air guide 39 is gripped under pressure between the rollers 44 and 46. The control computer C commands the opening of the electromagnetic valve V₁₀ and the actuation of the electric motor 43, as a result of which the blow nozzle 42 jets air flow and at the same time the weft transfer operation by the rollers 44 and 46 is started. When the weft has passed through the paired rollers 44 and 46 therebetween, the weft detector 40 detects the absence of the weft. In response to the weft absence detection signal of the detector 40, the control computer C commands the stoppage of the transfer motor 43. Additionally, the control computer C commands the closing of the electromagnetic valves V₁₀ and V₁₁ as well as deenergization of the electromagnetic solenoid 23. Thus, the air jet discharge from the blow nozzle 42 is stopped. Further, the rollers 44 and 46 are caused to move away from each other. The retainer pin 23a engages the weft winding drum surface 22b. In case no weft remains wound on the weft winding surface 22b, the weft detector 40 can never detect the presence of the weft. Unless the weft presence signal is obtained within a predetermined time period, the control computer C performs a weft feed operation, which will be described below in detail. The control computer C commands actuation of the blower 31 and at the same time opening of the electromagnetic valves V₇, V₆, V₅ and V₄. Consequently, between the blow nozzle 29 and the suction pipe 30, there is developed an air flow or stream directed toward the suction pipe 30, while the blow nozzles 29, 28 and 25 jet the air streams, respectively, causing the air to flow through the weft winding tube 22a in the direction from the tip or outlet end of the weft winding tube 22a toward the converging guide duct 27. The air flow blown out from the weft winding tube 22a is caused to be discharged in a convergent condition from the outlet of the convergent guide tube 27 under the converging action of the latter into a region between the blow nozzle 29 and the suction pipe 30 and merged to the air flow or stream developed between the blow nozzle 29 and the suction pipe 30 to be thereby introduced into the suction pipe 30. After the air flow having taken place along the path extending from the weft inserting guide 20 to the suction pipe 30, the control computer C commands energization of the electromagnetic valve V₂ to thereby trigger the retracting operation of the air cylinder 19. As a consequence, the suction arm 19 rotates downwardly about the supporting shaft 12a under gravity, as illustrated in Figs. 4 and 5, which in turn results in that the roller 13b mounted on the suction pipe 13 is caused to bear against the peripheral surface of the weft cheese 10A. In this state, the net 13a in the suction pipe 13 is positioned closely to the peripheral surface of the weft cheese 10A. Subsequently, the control computer C commands actuation of the blower 14, whereby suction takes place at the tip end of the suction pipe 13. Thereafter, the control computer C commands a predetermined amount of rotation for the motor 8, resulting in that the weft cheese 10A is caused to rotate for a predetermined angular distance. Due to the sucking action of the suction pipe 13 and the rotation of the peripheral surface of the weft cheese 10A, the leading end Y₁₁ of the weft on the weft cheese 10A is sucked by the suction pipe 13 through interposition of the net 13a, whereby the weft leading end Y₁₁ is held on the net 13a under suction. In this manner, the weft leading end Y₁₁ is held on the net 13a densely or in a congregated condition by suitably setting the amount of rotation of the weft cheese 10A. After rotation of the weft cheese 10A for a predetermined angular distance, the control computer C issues a command for deenergization of the electromagnetic valve V₂, whereby the suction pipe 13 is restored to the stand-by position. As a result of the restoration of the suction pipe 13, the leading end Y₁₁ of the weft held on the net 13a in the congregated state under suction is disposed in the vicinity of the innermost surface of the transporting guide 17. Starting from this state, the control computer C issues a command for opening the electromagnetic valve V₃, which is followed by jetting of air from the blow nozzle 18. The jetted air flow from the blow nozzle 18 sweeps over the innermost surface of the transporting guide 17, whereby the leading end Y₁₁ of the weft held on the net 13a in the congregated state is carried or transferred to the weft inserting guide 20 along the transporting guide 17, as illustrated in Fig. 7. The leading end Y₁₁ of the weft held on the net 13a in the congregated state effectively undergoes the jet action of the blow nozzle 18 because of the congregation thereof. More specifically, the area placed under the pressure brought about by the jet is extremely larger when the weft is in the congregated state as compared with the single weft lying linearly. Thus, by slightly increasing the jetting action of the blow nozzle 18 over the suction effect of the suction pipe 13, the transportation of the leading end of the weft in a satisfactory manner can be realized. In this manner, the leading end Y₁₁ of the weft led out from the periphery of the weft cheese 10A can be positively transported to the weft length-measuring and reserving apparatus 22. In other words, this ensures the transportation of the leading end Y₁₁ of the weft to the weft length-measuring and reserving apparatus 22 from the weft cheese 10A which is prerequisite for the successful threading to the weft length-measuring and reserving apparatus 22. In this conjunction, it is noted that in the case of the suction and gripping structure adopted heretofore for introducing the leading end of the weft under suction into the suction pipe, it was necessary to trim neatly the leading end of the introduced weft by a cutter. Unless this trimming is performed, the leading end of the weft placed in the suction pipe would present resistance to the transportation of the weft leading end to another place by the air flow, making it more difficult to transport the weft leading end gripped in a linear form. In contrast, in the case of the illustrated embodiment of the present invention, there exists no necessity for performing the trimming by a cutter as mentioned above, which in turn means that the relevant structure as well as the control involved can be much simplified to great advantage. The suction pipe 13 provided with the net 13a which ensures the positive weft transportation is ordinarily disposed and held at the stand-by position by means of the air cylinder 19 in the extended state. Accordingly, operation for causing the net 13a mounted at the tip end of the suction pipe 13 to approach to the periphery of the weft cheese 10A can be validated simply by retracting the air cylinder 19, i.e. simply by energizing the associated electromagnetic valve V₂. More specifically, when the electromagnetic valve V₂ is energized, the suction arm 12 swings downwardly under gravity until the roller 13b bears on the peripheral surface of the weft cheese 10A. This operation can take place independently of the diameter of the weft cheese 10A. Thus, the control for positioning the net 13a mounted at the tip end of the suction pipe 13 closely to the periphery of the weft cheese 10A can be simplified extremely regardless of the diameter of the weft cheese 10A. In the structure which allows the tip or free end of the suction pipe 13 to be automatically positioned under gravity in the vicinity of the periphery of the weft cheese 10A, the disposition of the weft cheese 10A at the weft draw-out position provides an important factor. Thus, when the weft cheese 10A at the weft delivery position has been exhausted and the other weft cheese 10B must be moved to the weft delivery position, as in the case of the illustrated embodiment of the invention, it is necessary to dispose the weft cheese 10B at the weft delivery position with the same orientation and configuration as the weft cheese 10A, i.e. to exchange the weft cheese 10A by the weft cheese 10B. To accomplish such exchange, the turn table 3 is rotatable in a horizontal plane in the case of the illustrated embodiment of the invention. This supporting structure is very advantageous from the standpoint of the balance in weight. In other words, by virtue of the supporting structure described above, the turn table 3 can be rotated very smoothly, which means in effect that the electric motor 4 may be of a small capacity. In case the weft threading has resulted in failure, e.g. the leading end of the weft Y₁ can not pass through the weft length-measuring and reserving apparatus 22, the weft Y₁ reaches short of the suction pipe 30. In that case, the weft presence detection signal is not obtained from the weft detector 32 within a predetermined time period. Accordingly, the control computer C commands the closing of the electromagnetic valves V₃, V₄, V₅, V₆ and V₇ as well as inhibition of operation of the blowers 14 and 31 and at the same time issues an alarm indication to an alarm device 49. When the weft Y₁ can be successfully threaded into the suction pipe 30, the control computer C commands the closing of the electromagnetic valves V₃, V₄, V₅, V₆ and V₇ as well as stoppage of the blower 14. At this time, the blower 31 still continues to rotate, whereby the leading end of the weft Y₁ is held under suction by the suction pipe 30. Starting from this state, the control computer C commands operation of the motor M by a predetermined amount to thereby cause the weft winding tube 22a to be rotated by a predetermined amount. In this way, there is preparatorily wound a predetermined amount or length of the weft Y₁ on the weft winding surface 22b. Subsequently, the control computer C commands a predetermined amount of rotation of the electric motor 34 and the energization of the electromagnetic solenoid 35. As a result, the weft grippers 33a and 33b now in the opened state are caused to pass through the tensioned region of the weft Y₁ while rotating, after which the weft grippers 33a and 33b are closed, whereby the weft Y₁ is gripped by the weft grippers 33a and 33b. The weft Y₁ as gripped is brought into contact with the stationary cutter blade 30a mounted on the suction pipe 30 to be cut and separated upon moving of the gripped weft Y₁ toward the entrance 26a of the weft inserting main nozzle 26. In this manner, the weft Y₁ extending from the weft grippers 33a and 33b is sized at a predetermined constant length, whereby the leading end of the sized weft Y₁ extending from the weft gripper 33a and 33b is disposed in the vicinity of the entrance 26a of the weft inserting main nozzle 26. Upon stoppage of the motor 34 after forward rotation thereof by a predetermined amount, the control computer C commands the energization of the electromagnetic solenoid 23 and at the same time the opening of the electromagnetic valves V₉ and V₈, whereby the retainer pin 23a is disengaged from the weft winding surface 22b while the blow nozzle 37 and the weft inserting main nozzle 26 produce air jets, respectively. This results in that an intake air flow occurs in the entrance 26a of the weft inserting nozzle 26, whereby the leading end of the weft Y₁ extending from the weft grippers 33a and 33b is introduced into the weft inserting main nozzle 26. Subsequently, the control computer C commands the deenergization of the electromagnetic solenoid 35 and the reverse or backward rotation of the motor 34 for the predeterminied amount. Thus, after releasing the leading end of the weft Y₁, the weft grippers 33a and 33b are restored to the stand-by position. On the other hand, the leading end of the weft Y₁ placed in the weft inserting main nozzle 26 is blown out therefrom to be introduced into the weft introducing duct 38 under the jet action of the blow nozzle 37. When the leading end of the weft Y₁ has attained the position of the weft detector 40 installed within the air guide 39, the control computer C performs in succession subsequent weft processing on the basis of the weft presence detection information from the weft detector. When the threading of weft through the weft inserting main nozzle 26 has failed, the leading end of the weft Y₁ cannot reach the position of the weft detector 40. Thus, the control computer C monitors wether or not the weft presence detection information is obtained from the weft detector 40 within the preset time duration and unless the information is obtained, the control computer C commands the closing of the electromagnetic valves V₈ and V₉ as well as the deenergization of the electromagnetic solenoid 23, as a result of which the jetting operation of the weft inserting main nozzle 26 and the blow nozzle 37 is interrupted and at the same time the retainer pin 23a is caused to engage with the weft winding surface 22b. So long as the number of times the weft threading ended in failure has not attained a preset number n , processing operation succeeding to the winding of the weft for reservation on the weft length-measuring and reserving apparatus 22 is performed by the control computer C and, if otherwise, the latter issues a command for stopping operation of the blower 31 and activating the alarm apparatus 49. When the weft threading has ended successfully, the control computer C responds to the weft presence detection signal output from the weft detector 40 to issue commands for closing the electromagnetic valves V₈ and V₉, stoppage of operation of the blower 31 and deenergization of the electromagnetic solenoid 23, respectively. In succession, the control computer C commands the energization of the electromagnetic valve V₁₁ to thereby cause the air cylinder 45 to extend, whereby the driven roller 46 is brought into contact with the driving roller 44, resulting in that the weft Y₁ is held between both the rollers 44 and 46. Subsequently, the control computer C commands rotation of the motor M by a predetermined amount to cause the weft Y₁ to be wound for reservation by a predetermined amount. After the weft winding for reservation, the control computer C commands the opening of the electromagnetic valve V₁₀ and at the same time operation of the weft transfer motor 43. Thus, the weft Y₁ is transferred and cut in the state under tension by the stationary cutter blade 26b. The fragment of the weft resulting from the cutting is transferred to the rollers 44 and 46 to be discharged into the dust box by the blow nozzle 42. When the entire length of the weft Y₁ resulting from the cutting has passed through the air guide 39, the weft detector 40 detects the absence of the weft. In response to the weft absence detection information, the control computer C commands the stoppage of operation of the motor 43 and the deenergization of the electromagnetic valve V₁₁. Consequently, the weft transfer motor 43 stops operation to allow the paired rollers 44 and 46 to move away from each other. Subsequently, the control computer C commands the closing of the electromagnetic valve V₁₀, whereby the air jetting operation of the blow nozzle 42 is terminated. Then, the loom is rotated to the start position, whereupon the loom is restarted. Referring to Fig. 12, there is provided an arm 50 rotatably supported so as to swing downwardly under gravity as in the case of the suction arm 12 of the preceding embodiment. The arm 50 is provided at the free or tip end portion thereof with a brush 51. When the arm 50 has been swung under gravity, the roller 50a bears on the peripheral surface of the weft cheese 10A so that the free end of the brush 51 is in contact with the peripheral surface of the weft cheese 10A, as indicated by a broken line. Accordingly, as the weft cheese 10A is rotated, the tip end of the brush 51 sweeps the peripheral surface of the weft cheese 10A in the relative sense, as a result of which the leading end portion of the weft Y₁₁ drawn or led out from the weft cheese 10A adheres to the tip end of the brush 51 in the congregated state. The holding of the weft Y₁₁ by the brush 51 in the congregated state can be realized only by adhesion effective between the tip end of the brush 51 and the weft. Accordingly, the weft Y₁₁ adhered to the brush 51 in the congregated state can be easily detached under the jetting action of the blow nozzle 21. By virtue of the structure for holding the weft Y₁₁ in the congregated state without relying on the suction effect, the associated mechanism as well as the control thereof can be significantly simplified. Of course, it goes without saying that the suction effect may be added to the adhesive action of the brush 51. In that case, the draw-out of the leading end of the weft from the periphery of the weft cheese 10A can be ensured with an enhanced reliability.

Claims: A weft processing apparatus in a jet loom including a weft supply (10A) having a peripheral surface around which a length of weft (Y1) is wound, and means (22) for measuring a length of weft fed from said weft supply and for reserving the measured weft therein, the weft length-measuring and reserving means having a weft introducing port (20a) to receive therein the weft fed from the weft supply (10A) said apparatus comprising: means (13, 14, 15, 51) for releasing the leading end (Y11) of the weft from the peripheral surface of the weft supply (10A) and for moving said leading end (Y11) away from said supply to a stand-by position; means (18) for jetting a fluid to move, by the jetted fluid, the weft leading end from said stand-by position to the weft introducing port (20a) of the weft length-measuring and reserving means (22); and a guide surface (17) along which the weft leading end is movable toward said weft introducing port (20a) together with said jetted fluid from said fluid jetting means (18) into said weft introducing port (20a). A weft processing apparatus as set forth in Claim 1, wherein said weft releasing means (13, 14, 15, 51) comprises a suction means (13, 14, 15) in the form of a suction pipe (13) having an intake port for generating a suction air stream to suck the leading end (Y11) of the weft therein. A weft processing apparatus as set forth in Claim 2, wherein said intake port is provided with means (13a) for congregating the weft leading end (Y11) sucked in said intake port and temporarily holding the congregated weft. A weft processing apparatus as set forth in Claim 3, wherein said weft congregating and holding means is in the form of a net (13a) having a mesh structure. A weft processing apparatus as set forth in Claim 3, wherein said weft congregating and holding means is in the form of a brush (51). A weft processing apparatus as set forth in Claim 3, further including means for changing over said weft congregating and holding means (13a, 51) between an operative position adjacent the weft supply (10A) in which said weft congregating and holding means receives the weft leading end (Y11), and a stand-by position, wherein when said weft congregating and holding means (13a, 51) holding the congregated weft leading end (Y11) is changed over to said stand-by position, said congregated weft leading end is moved to said weft introducing port by the fluid jetted from said fluid jetting means (18). A weft processing apparatus as set forth in Claim 6, wherein said guide means comprises a weft transporting guide (17) having one end portion (17a) disposed adjacent said weft supply (10A) and the other end portion disposed adjacent said weft introducing port (20a), at least said other end portion,which orthogonally intersects with the direction of the fluid flow jetted from said fluid jetting means, being open. A weft processing apparatus as set forth in Claim 7, wherein a window (17a) is formed in said one end portion of said weft transporting guide (17), said intake port of said suction pipe (13) being able to move into and out of said window (17A), and wherein said fluid jetting means (18) is mounted on said weft transporting guide (17) at said one end portion so as to direct said jetted fluid toward said other end portion of said weft transporting guide.

Inventors: MITSUYA KINPEI C O KABUSHIKI K, MURATA MASAHIKO C O KABUSHIKI, MITSUYA, KINPEI, C/O KABUSHIKI KAISHA TOYODA, MURATA, MASAHIKO, C/O KABUSHIKI KAISHA TOYODA
Applicants: TOYODA AUTOMATIC LOOM WORKS, KABUSHIKI KAISHA TOYODA JIDOSHOKKI SEISAKUSHO
Application year: 1990
Main classification: D03D47
IPC codes: B65H67, D03D47