Before weaving can commence, a variety of preparatory operations have to be carried out. For example, as a drawing-in operation, a large number of warp threads wound on the warp beam are required to be passed one by one through the eyes of a heddle and drops. For this drawing-in operation, various kinds of automated drawing-in apparatuses have been employed. Further, a variety of methods and apparatuses have been developed to automatically feed the warp threads one by one to the drawing-in apparatus. For example, as such apparatuses, the applicant of the present invention has proposed in Japanese patent application No. 62-153001 (which has not been published yet) a thread feed apparatus as shown in FIGS. 8-11. In FIG. 8, reference numeral 1 designates a warp beam on which a large number of threads 2 are wound, the warp beam 1 being supported horizontally to a horizontal frame 4 of a drawing frame 3. The threads 2 on the warp beam 1 are unwound from the beam 1 and then drawn tautly by upper and lower drawing channel beams 6 and 7 mounted horizontally on an upright stand 5 of the drawing frame 3, in order to provide a large number of parallel threads 2 each having a length required to the thread drawing-in operation, as shown in FIG. 9. Since the parallel threads 2 are drawn tautly by hand, gripping plates 8 and 9 are inserted into the grooves formed in the drawing channel beams 6 and 7 in order to facilitate the drawing of the parallel threads 2. After the parallel threads 2 have been gripped by the gripping plates 8 and 9, they are drawn tautly by moving the drawing beams 6 and 7 away from each other by suitable means (not shown). In FIG. 9, reference numerals 10 and 11 denote a pair of leasing threads each passing in and out between the leading ends of the parallel threads 2. The leasing threads 10 and 11 are provided to easily separate the parallel threads 2 from one another.
FIGS. 10 and 11 schematically illustrate a thread feed apparatus 13 which feeds to a thread drawing-in apparatus 12 the parallel threads 2 drawn tautly to the drawing frame 3 as described above. The drawing frame 3 shown in FIG. 8 is moved laterally with the aid of the wheels 14 of the horizontal frame 4, together with the warp beam 1, and connected to the front face of a frame 15 of the thread drawing-in apparatus 12 shown in FIG. 10. The thread feed apparatus 13 extends between the drawing beams 6 and 7 of the connected drawing frame 3 along the frame 15. The thread feed apparatus 13 comprises a cutter 16, a leasing tube 17 for the leasing threads 10 and 11, a hook 18 for separation, a warp chuck 19, a suction block 20, a warp lowering hook 21, a warp holding hook 22, and a warp holding bar 23. Reference numerals 24 and 25 indicate a suction nozzle and guide nozzle of the thread drawing-in apparatus 12, respectively. The thread 2 fed by the thread feed apparatus 13 is drawn in with the aid of the injection effect of compressed air and passed through the eye of a drop 26 positioned between the suction nozzle 24 and the guide nozzle 25. While only a pair of the suction and guide nozzles 24 and 25 are shown, a large number of pairs of the suction and guide nozzles are provided so that the thread can be passed through the eyes of the heddles and drops at the same time. These nozzles constitute the major parts of the thread drawing-in apparatus 12.
In FIG. 11, among a large number of the parallel threads 2 drawn tautly to the thread feed apparatus 13, the thread end of the most right thread 2 in FIG. 11 is released from the leasing threads 10 and 11 by the leasing tube 17, and gripped and moved rightward by the separation hook 18. The thread end of the thread 2 is gripped by the advancing warp chuck 19, as shown by the imaginary line in FIG. 10, and is then cut in the vicinity of the drawing beam 6 by means of the cutter 16. At the same time, the upper half portion of the cut thread 2 is drawn into the suction block 20 through a vertically extending groove 20a formed in the front face of the suction block 20 by means of a vacuum pressure, as shown by the imaginary line. The warp holding hook 22 is then moved toward the suction block 20 so that a bridge portion 2a is formed between the holding hook 22 and the war holding bar 23. Thereafter, the warp lowering hook 21 is lowered together with a belt 28 which is driven by rotation of a drive pulley 32. As the hook 21 is lowered, the bridge portion 2a of the thread 2 is lowered to the drawing beam 7, and the thread end of the thread 2 is guided by the suction block 20 and lowered to a position adjacent to the suction nozzle 24, as shown by the broken line in FIG. 10. At the same time, as shown by the imaginary line in FIG. 11, the warp holding bar 23 is rotated downward to release the lower portion of the thread 2 in the side of the drawing beam 7. Consequently, the thread 2 is drawn through the eye of the drop 26 by the suction nozzle 24. The gripping force with which the warp chuck 19 grips the thread 2 has been set so that the thread 2 can be easily released from the chuck 19 by the down movement of the warp lowering hook 21. In FIGS. 10 and 11, reference numerals 29, 30 and 31 indicate nozzles which are connected to a vacuum source to introduce a vacuum pressure into the suction block 20. Reference numeral 27 indicates a driven pulley over which the belt 28 driven by the drive pulley 32 passes. Reference numeral 33 indicates a nozzle which supplies compressed air to the suction nozzle 24. Besides the thread feed apparatus 13 constructed as described above, there is also known another thread feed apparatus of the type in which a taut thread is gripped at its thread end by one end of an arm member and guided to the suction nozzle 24 of the thread drawing-in apparatus 12 by rotation of the arm member about the other end thereof. In either case, a large number of threads that have been drawn tautly to the drawing frame 3 or similar frame are fed one by one to the thread drawing-in apparatus 12.
However, the above described thread feed apparatus (which has not been published yet) or conventional thread feed apparatus has the following drawbacks (i)-(v), since after a large number of parallel threads have been drawn tautly to the drawing frame or similar frame, they are separated one by one and fed one by one to the thread drawing-in apparatus.
(i) An apparatus incident to the thread drawing-in apparatus increases the cost of apparatus, since there is the need for a drawing frame to draw threads tautly from a warp beam, or for a feed apparatus of high speed and high accuracy to feed the tautly drawn threads one by one to the thread drawing-in apparatus. PA1 (ii) The working load of workers engaged in the thread drawing-in operation is increased, and the thread drawing-in cost and accordingly the production cost of final products (textile fabrics) becomes large. That is to say, since several thousands of threads are wound on one warp beam and required to be drawn tautly on the drawing frame by the workers, the production cost is increased. PA1 (iii) The space for apparatuses required to the thread drawing-in operation and space for work become large and therefore add to the overall area of the textile factory. Since the space for an apparatus incident to the drawing-in apparatus is large and since the travel space for the drawing frame or working space for drawing threads tautly becomes large, these spaces add to the overall area of the textile factory. PA1 (iv) The thread drawing-in rate is greatly reduced, depending upon the nature and characteristics of the thread. A variety of threads, for example, nappy threads, stiff threads or very fine threads are used to make textile fabrics. Since the separation of the thread ends of the threads having such nature and characteristics is very difficult, the supply of the threads is not performed smoothly. In addition, the thread tends to be hooked on the apparatus and cut due to the insufficient flexibility and nap of the thread. Since particularly very fine threads tend to be easily cut, the thread drawing-in rate is greatly reduced. PA1 (v) Since the number of threads wound on one beam has a limit and since the beam mounted to the drawing frame is normally limited to one, the thread drawing-in operation of wide textile cloth wherein the number of warp threads is large was difficult.
Accordingly, it is an objective of the present invention to provide an improved method and apparatus for feeding threads which can overcome the above described drawbacks (i)-(v).