MENDING YARN TRIMMING METHOD AND A DEVICE FOR CARRYING OUT THE SAME

Abstract: A mending yarn trimming method and a device for carrying out the same. When a warp yarn is broken during the operation of the loom, one end of a mending yarn and the broken end of the broken warp yarn extending from the warp beam are tied together, the other end of the mending yarn is passed through a corresponding heddle and a corresponding gap between the dents of a reed, and then the loom is restarted. The free end of the mending yarn is cut off automatically from the woven cloth by the mending yarn trimming device while the loom is in operation.

Description: The present invention relates to a mending yarn trimming method and a device for carrying out the same, in which, in mending a broken warp yarn, one end of a mending yarn is tied to the broken warp yarn, the other end of the mending yarn is passed through the heddle and the reed, the loom is restarted, and then the free end of the mending yarn is cut automatically during weaving operation. When a warp yarn is broken during weaving operation, a dropper device or the like generates a warp stop signal to stop the loom automatically. Then, an operator picks up the broken warp yarn from a series of parallel warp yarns, ties a mending yarn to the leading broken end of the broken warp yarn, passes the mending yarn through the heddle and the reed, and restarts the loom holding the free end of the mending yarn near the cloth fell by hand or with a magnetic clipper. After a sufficient length of the mending yarn has been woven in the cloth, the operator cuts off the free end of the knot of the warp yarn and the mending yarn projecting from the surface of the woven cloth. Such a conventional mending operation is carried out entirely by the manual work of the operator, which is inefficient. Moreover, the hand of the operator holding the free end of the mending yarn is exposed to the danger of beating by the reed and it is possible that the reed is damaged by the cutter in cutting off the free ends of the knot. Accordingly, it is an object of the present invention to enable the automatic removal of the free end of the mending yarn in mending the broken warp yarn. As mentioned above, the dropper device or the like generates a warp stop signal to stop the loom automatically when a warp yarn is broken during weaving operation. The position of the broken warp yarn corresponds to the position of a dropper which has fallen. The broken warp yarn is picked up from the warp yarns, for example, by an invention: "A Method of Automatically Extracting a Broken Warp Yarn and a Device for Carrying out the Same" disclosed in Japanese Patent Laid-open Publication No. 62-69851. Then, an operator ties the broken warp yarn extending from the warp beam to a mending yarn by hand or with an automatic knotter. Then, the mending yarn is passed through the heddle and the reed, and is extended toward the cloth fell. Then, the free end of the mending yarn is removed automatically by the present invention. First, a moving member of a mending yarn trimming device moves, together with a yarn holding member, widthwise of the cloth from a standby position near the selvedge of the cloth, and stops near the broken warp yarn, secondly, the yarn holding member holds the mending yarn at a fixed tension at the free end of the same. In this state, the loom is ready to restart. Then, a start signal is given to restart the loom. Among the free ends of the mending yarn, the portion positioned toward the cloth fell from the shed via held, is not woven when the loom is restarted, but remains floating over the cloth and advances as the loom proceeds with the weaving operation. On the other hand, the sensor of the mending yarn trimming device gives an actuation signal to a cutter upon the detection of the arrival of the free end of the mending yarn projecting from the cloth at a predetermined position. Then, the cutter cuts off the free end of the mending yarn at a position near the root to remove the unnecessary free end of the mending yarn. Naturally, in cutting off the unnecessary portion of the mending yarn, and end of the unwoven mending yarn is held by the cloth just woven and the other free end of the mending yarn is held by the yarn holding member to keep the mending yarn at a predetermined tension to facilitate cutting the unnecessary portion of the mending yarn with the cutter. Thus, the free end of the mending yarn is removed automatically. Naturally, a series of steps of the mending yarn trimming operation is controlled by a controller. Thus, according to the present invention, and the free end of the mending yarn projecting from the upper surface of the cloth is cut off automatically. Furthermore, according to the present invention, the woven fabric among the broken warp yarn is simultaneously subjected to trimming. Therefore, the operator can be disengaged from the broken warp yarn mending work as soon as the operator has given a signal to restart the loom, so that the operator is able to start the next work. Since the free end of the mending yarn is removed mechanically, the operator need not perform any dangerous work in mending a broken warp yarn, and damages in the reed or in the cloth attributable to faulty work are prevented. The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic perspective view of a mending yarn trimming device in a first embodiment according to the present invention; Figs. 2 and 3 are enlarged side elevations showing an essential portion of the mending yarn trimming device of Fig. 1; Fig. 4 is a horizontal sectional view showing a guide tube and a cutter incorporated into the mending yarn trimming device of Fig. 1; Fig. 5 is a block diagram showing a control system for controlling the mending yarn trimming device of Fig. 1; Fig. 6 is a fragmentary, schematic side elevation of a loom of assistance in explaining mending yarn trimming operation; Fig. 7 is a flow chart of assistance in explaining the operation of the mending yarn trimming device of Fig. 1; Figs. 8 and 9 are enlarged side elevations respectively showing essential portions of second and third embodiments of the present invention; and Fig. 10 is a sectional view of an essential portion of a fourth embodiment of the present invention. DETAILED OF THE PREFERRED EMBODIMENTS First Embodiment (Figs. 1 through 5): A mending yarn trimming device 1 is mounted on a moving member 2, which in turn is supported on a guide rail 4 extended widthwise of the loom over a woven cloth 3 for movement in the direction of the width of the loom. The moving member 2 is moved to a desired position by a driving device including, for example, a driving screw 5, a driven nut 6 and a motor 7. Parallel warp yarns 9 arranged in a sheet are controlled by the vertical motions of heddles 15 to form a shed, a weft yarn 10 is picked into the shed across the warp yarns 9 and is beaten with a reed 11 into the cloth fell 8 to form the woven cloth 3. The woven cloth 3 is drawn by guide rollers 12 and 14 and a take-up roller 13. The mending yarn trimming device 1 has a tubular holder 16 depending vertically from the lower surface of the moving member 2, and a suction pipe 17, namely, a yarn holding member, attached to the lower end of the tubular holder 16. The suction pipe 17 is vertically retractable into the tubular holder 16 and is connected by a connecting plate 20 to the piston rod 19 of an actuator 18 fixed to the tubular holder 16 to move the suction pipe 17 in vertical directions. A cutter 23 is supported at one end thereof on the side of the take-up system on the connecting plate 20 by a vertical supporting rod 21 and is urged downward by a coil spring 22 mounted on the supporting rod 21. The cutter 23 is connected at the rear end thereof to a cutter driving unit 24. The cutter driving unit 24 has a guide rod 25 slidable in vertical directions relative to the connecting plate 20. The upper end of the suction pipe 17 is connected through a waste yarn container 26 formed of a net, and a solenoid valve 27 to a vacuum source 28. A signalling device 29, for example, a photoelectric sensor, is provided on the lower end of the suction pipe 17 on the side of the take-up system. A controller 30 controls the operation of the mending yarn trimming device 1 according to a control program embodying a method of the present invention. As shown in Fig. 5, the input section of the controller 30 is connected to the signaling device 29, a dropper device 31 and a command switch 36, while the output section of the same is connected to a motor control circuit 32 for controlling the driving motor 7, a selector valve 34 disposed in a line interconnecting the actuator 18 to a pressure source 33, and a cutter driving unit 24. Both the input section and output section of the controller 30 are connected bilaterally to the main controller 35 of the loom. The operation of the mending yarn trimming device 1 will be described hereinafter. While the loom is in operation, the moving member 2 is held in standby near one of the selvedges of the woven cloth 3 so that the weaving operation of the loom will not be interfered with the mending yarn trimming device 1. Upon the detection of the breakage of the warp yarn 9, the dropper device 31 gives a warp stop signal to the main controller 35 of the loom. Then, the main controller 35 stops the loom automatically at a predetermined stopping phase angle. Then, as shown in Fig. 6, an operator or the aforesaid automatic broken warp extracting device of Japanese Patent Laid-open Publication No. 62-69851 picks up the free end of the broken warp yarn 9 extending from the warp beam, ties the broken warp yarn 9 and a mending yarn 37 together and passes the free end of the mending yarn 37 through the corresponding heddle 15 and the corresponding gap between the dents of the reed 11 to pull out the free end of th mending yarn 37 on the side of the cloth fell 8. Then, the operator operates the command switch 36 to give a start signal to the controller 30. Then, the controller 30 starts controlling the mending yarn trimming device 1 according to a predetermined control program to carry out an operation necessary from trimming the mending yarn 37. Referring to Fig. 7, first, the controller 30 drives the driving motor 7 on the basis of information about the position of the broken warp yarn 9 given thereto by the dropper device 31 to move the moving member 2 to a position corresponding to the broken warp yarn 9, controls the selector valve 34 to lower the suction pipe 17 by the actuator 18 to a position above the cloth fell 8, and then opens the solenoid valve 27 to generate an air current flowing into the suction pipe 17. Then, the free ends of the mending yarn 37 and the broken warp yarn 9 are sucked into the suction pipe 17 by the air current. In this state, since the free ends of the broken warp yarn 9 and the mending yarn 37 extending toward the cloth are extending within the suction pipe 17 on the side of the cloth fell 8 as shown in Fig. 2, the free ends of the broken warp yarn 9 and the mending yarn 37 are outside the range of detection of the signalling device 29. Then, the operator gives a start signal to the main controller 35 to restart the loom for weaving operation. As the loom proceeds with the weaving operation, among the free ends of the mending yarn, the portion positioned toward the cloth fell from the shed via held and a portion of the broken warp yarn 9 extending from the cloth 3 are not woven but remains floating above the cloth 3 move gradually toward the take-up system, and finally, enter the region of detection of the signalling device 29. Upon the detection of the free end of the mending yarn 37, the signalling device 29 gives a detection signal to the controller 30. In this state, the free end of the mending yarn 37 and the free end of the broken warp yarn 9 are within the suction pipe 17 and they are is in a cutting range under tension. Upon the reception of the detection signal from the signaling device 29, the controller 30 actuates the cutter driving unit 24 to cut off the free ends of the mending yarn 37 and the broken warp yarn 9 extending from the cloth 3 with the cutter 23 so that the free ends of the mending yarn 37 and the broken warp yarn 9 project by a predetermined length from the upper surface of the cloth 3. Since air is sucked continuously into the suction pipe 17 during this cutting operation, the cut free ends of the mending yarn 37 and the broken warp yarn 9 are delivered by the air current to the waste yarn container 26. Subsequently, the controller 30 controls the selector valve 34 a predetermined time period after cutting the free ends of the mending yarn 37 and the broken warp yarn 9 to make the actuator 18 raise the suction pipe 17, closes the solenoid valve 27 to stop the suction of the suction pipe 17, and then, or simultaneously with the operation for stopping the suction of the suction pipe 17, controls the motor control circuit 32 to return the mending yarn trimming device 1 to the predetermined standby position thus completing a series of control operation. Second Embodiment (Fig. 8): A mending yarn trimming device in a second embodiment according to the present invention incorporates a pair of drawing rollers 41 and 42 disposed within a suction pipe 17. The drawing roller 41 is a driving roller disposed at a fixed position so as to be driven by a motor 43. The other drawing roller 42 is a driven roller rotatably supported on the extremity of the piston rod 45 of a pneumatic actuator 44 so as to be pressed against the driving drawing roller 41. In the second embodiment, the suction pipe 17 is not connected to any vacuum source 28; a venturi tube 47 is formed within and at the lower end of the suction pipe 17. Pressurized air is supplied from a pressurized air source 46 into the suction pipe 17 so that a suction is generated at the lower end of the suction pipe 17 by the cooperate agency of the suction pipe 17 and the venturi tube 47. A yarn detector 48 is provided on the suction pipe 17 above the pair of drawing rollers 41 and 42. When air is blown through the venturi 47, a suction is generated at the lower end of the suction pipe 17 to suck the free end of a mending yarn 37 into the suction pipe 17, and then the yarn detector 48 detects the presence of the free end of the mending yarn 37 within the suction pipe 17. After the loom has been restarted, the pneumatic actuator 44 advances the piston rod 45 to press the driven drawing roller 42 against the driving drawing roller 41. Then, the controller 30 actuates the motor 43 to drive the driving drawing roller 41 at a circumferential speed corresponding to the moving speed of the cloth 3 during the weaving operation, so that the mending yarn is drawn at a speed corresponding to the moving speed of the cloth 3. A signalling device 29 capable of measuring a predetermined time period from the restart of the loom or a predetermined number of picking cycles from the restart of the loom gives a signal to the controller 30 to actuate the cutter 23 to cut off the free end of the mending yarn 37 a predetermined time period or a predetermined number of picking cycles after the restart of the loom. The signaling device 29 is a timer or a pick counter. The cut free end of the mending yarn 37 is drawn further by the drawing roller 41 and 42 and, eventually, leaves the drawing rollers 41 and 42. Then, the mending yarn 37 is carried by an air current to a predetermined place. The rest of the operating steps of the mending yarn trimming device in the second embodiment are the same as those of the mending yarn trimming device in the first embodiment. The pressurized air is blown continuously into the suction pipe 17 while the free end if the mending yarn 37 is nipped between the pair of drawing rollers 41 and 42. However, the supply of the pressurized air into the suction pipe 17 may be interrupted during the operation of the pair of drawing rollers 41 and 42 to avoid breaking the mending yarn 37 by the untwisting action of the air current. Third Embodiment (Fig. 9): A suction pipe 17 incorporated into a mending yarn trimming device in a third embodiment according to the present invention is not placed at a fixed position with respect to the moving member 2. The suction pipe 17 is supported pivotally for swing motion on the tubular holder 16 by a horizontal shaft 51 so that the lower end thereof is able to move along the direction of extension of the warp yarns 9. The suction pipe 17 is driven for swing motion by a motor 52. The free end of the mending yarn 37 is sucked into the suction pipe 17 by an air current flowing into the suction pipe 17 by an air current flowing into the suction pipe 17, a mending yarn detector 53 detects the free end of the mending yarn 37 sucked into the suction pipe 17, and then a pair of clamping members 54 and 55 clamps the free end of the mending yarn 37. One of the clamping members 54 and 55, namely, the clamping member 54 in this embodiment, is driven by an actuator 56, such as a pneumatic actuator or an electromagnetic actuator. As the mending yarn 37 moves in the take-up direction in synchronism with the weaving operation of the loom, the suction pipe 17 is driven by the motor 52 so as to move in the direction of movement of the cloth 3 as the cloth 3 moves so that the mending yarn 37 is kept under tension. Upon the arrival of the mending yarn 37 at a cutting position, the cutter 23 is actuated to cut off the free ends of the mending yarn 37 and the broken warp yarn 9 projecting from the upper surface of the cloth 3. The cutter 23 is held on a bracket 57 fixed to the moving member 2. In the foregoing embodiments, the loom is restarted by the operator after the free ends of the mending yarn 37 and the broken warp yarn 9 have been sucked into the suction pipe 17. However, when a yarn detector is provided within the suction pipe 17 to detect the suction of the free ends of the mending yarn 37 and the broken warp yarn 9, the loom can be restarted automatically, and hence the operator needs only to give a start command to the controller 30 after passing the free end of the mending yarn 37 through the corresponding heddle 15 and the corresponding gap between the dents of the reed 11. Fourth Embodiment (Fig. 10): A mending yarn trimming device in a fourth embodiment according to the present invention is substantially the same as that in the first embodiment, except that the mending yarn trimming device in the fourth embodiment employs a suction pipe 17 having a guide 171 to guide the mending yarn 37 along the surface of the cloth 3 so that the mending yarn 37 can surely be woven into the cloth.

Claims: A mending yarn trimming method comprising steps of: holding the free end of mending yarn (37) tied to a broken warp yarn (9) after the loom has been stopped at a predetermined stopping phase angle.; detecting the arrival of the free end of the mending yarn (37) at a predetermined position after the free end of the mending yarn (37) has advanced after the loom has been restarted; and cutting off the free end of the mending yarn (37) from the woven cloth (3) after the detection of arrival of the free end of the mending yarn at the predetermined position. A mending yarn trimming device comprising: a moving member (2) supported above the woven cloth for movement widthwise of and along the woven cloth; a yarn holding means (17) mounted on the moving member (2) to hold the free end of a mending yarn (37) tied to a broken warp yarn (9) so that the free end of the mending yarn (37) is extended substantially at a predetermined tension; a signaling device (29, 48, 53) which generates a signal upon the detection of arrival of the free end of the mending yarn (37) which was not woven into the cloth after the loom has been restarted at a predetermined position; a cutter (23) for cutting the free end of the mending yarn (37) extending from the woven cloth so that a predetermined length of the mending yarn remains on the woven cloth; and a controller (30) for controlling the moving member (2), the holding member (17) and the cutter (23) for operation according to a predetermined control program. A mending yarn trimming device according to Claim 2, wherein the yarn holding means (17) comprises a suction pipe through which a suctional air current flows. A mending yarn trimming device according to Claim 2, wherein the yarn holding means (17) comprises a suction pipe through which a suctional air current flows, and a pair of drawing rollers (41, 42) disposed within the suction pipe so as to be driven for rotation at a circumferential speed equal to the moving speed of the woven cloth. A mending yarn trimming device according to Claim 2, wherein the yarn holding means (17) comprises a suction pipe supported for motion in the direction of extension of the warp yarns, and a pair of clamping members (54, 55) provided within the suction pipe.

Inventors: TAKEGAWA, YURIJO
Applicants: TSUDAKOMA CORPORATION
Application year: 1988
Main classification: D03J1
IPC codes: D03D51, D03J1