Piecing method and device for a spinning machine

Abstract: Piecing method of a spinning machine whereby, after holding outside a twist device (T) both a leading yarn (Y') ejected from the sliver guide (5) entrance of a twist device (T) in a stationary state and a sliver (6) delivered by a re-operated draft device (D), the twist device (T) is operated, the sliver (6) supplied to the twist device (T) and the fibers comprising the sliver (6) are entangled in the leading yarn (Y') pulled from the twist device (T). The success rate of yarn piecing may be improved without detailed adjustment of the pulling timing of the leading yarn (Y') guided into the twist device (T) and the supply timing of the sliver (6) supplied to the twist device (T).

Description: The invention relates to a yarn piecing method according to the preamble of claim 1 and a piecing device for performing it. WO-A-9400626 discloses a piecing method of a spinning machine which is effected by sucking a leading yarn into a suction pipe. The leading yarn is then returned to the front rollers of a drawing device and suct into a further suction pipe. This suction pipe is positioned between a spinning unit and the front rollers of the drawing device. For piecing the suction air current of the further suction pipe is stopped, and the sliver and the leading yarn are combined at the entrance of the spinning unit and then introduced into it. During piecing the leading yarn is lead through the front rollers of the drawing device and therefore flattened by the nipping of the leading rollers. Furthermore it is necessary to adjust the timing with which the leading yarn is inserted into the front rollers and with which the sliver is supplied. The problem underlying the invention is to propose a piecing method and a piecing device for performing it by which a deformation of the leading yarn is prevented. This problem is accomplished by the features of the characterizing part of claim 1. A piecing device for performing this method is defined in claim 2. According to the invention the leading yarn is not introduced into the drawing device and therefore not deformed. Furthermore the supply of the sliver can be started with the leading yarn drawn in by the suction pipe, thereby enabling the running of the leading yarn to be started with both the sliver and the leading yarn drawn in by the suction pipe, thereby enabling the running of the leading yarn to be started with both the sliver and the leading yarn drawn in by the suction pipe without the need for a detailed adjustment of the pulling time of the leading yarn guided to the twist device and the supply timing of the sliver supplied to, and the piecing device may therefore be simplified. The invention will now be described by way of example and with reference to the accompanying drawing in which: Fig. 1 - 5 show a spinning unit having a piecing device for illustrating different steps of the method according to the invention, Fig. 6 is an expanded section of the twist device, and Fig. 7 is a timing charge of the yarn piecing method of the invention. Firstly, a spinning unit of a spinning machine being one embodiment to which the piecing method of the invention is applicable will be described using Figures 1 and 6. D is a draft device showing a four line type draft device as an example. The draft device D comprises the four lines being back rollers 1, third rollers 2, middle rollers 3 attached with an apron belt and front rollers 4. 5 is a sliver guide and sliver 6 inserted in the sliver guide 5 and supplied to the draft device D is supplied to a twist device which will be described later and produces yarn Y after being supplied to the draft device D and drawn. A twist device T comprises mainly an air spinning nozzle 7 which produces a spinning air current by the blowing of pressured air, a nozzle block 8 which supports that nozzle 7, a spindle (yarn guide tube) 9 having an insertion hole 9b and of which the tip 9a is positioned in the inner part 7a of the air spinning nozzle 7, and a spindle support member 10. The inner part 7a of the air spinning nozzle 7 is the piecing area where joining of the fibers comprising the sliver 6 supplied to the inner part 7a of the air spinning nozzle 7 and the winding side spun yarn Y inserted into the insertion hole 9b of the spindle 9 and guided into the inner part 7a of the air spinning nozzle 7 is carried out. A plurality of air blowing holes 7b for generating a rotating air current are arranged in the air spinning nozzle 7. 11 is an air chamber formed between the nozzle block 8 and spindle support member 10. The air chamber 11 is connected to an air suction source (not shown in the drawings) that sucks air at a low suction pressure via the suction hole 12 and during spinning, acts as an escape hole for the air blown from the air blowing boles 7b of the air spinning nozzle 7 as well as removing fly fiber waste and the like generated inside the air chamber 11 during spinning. 13 is an air blowing hole arranged in the spindle 9 and spindle support member 10 for generating an air current in the direction of the tip 9a of the spindle 9. The air blowing hole 13 is connected to the compressed air supply source (not shown in the drawings) via a pipe 14 connected to the spindle support member 10. 15 is a slit formed in the side wall of the nozzle block 8 side spindle support member 10. 16 is a slit formed in the side wall of the spindle support member 10 side nozzle block 8 opposite the slit 15 of the spindle support member 10. As described later, when the nozzle block 8 and spindle support member 10 are coupled together, the leading yarn inserted in the insertion hole 9b of the spindle 9 enters the slits 15, 16 and the arrangement is such that it is not trapped by the side wall of nozzle block 8 and the side wall of the spindle support member 10. 17 is a cylinder. A lower frame 19 of the spindle support member 10 is mounted on the tip of a piston rod 18 of the cylinder 17. Accordingly, the cylinder 17 is moved and the spindle support member 10 is able to be coupled with or separated from the nozzle block 8 by the left and right movements of the lower frame 19. 20 is a suction pipe of which the tip is positioned between the nozzle block 8 and front roller 4 and connected to the suction air source (not shown in the drawings). 21 is a nip roller being connectable with or separable from the delivery roller 22 which is normally always driven and is so arranged that the spun yarn Y is delivered in the direction of the winding machine (not shown in the drawings) by connecting the nip roller 21 with the delivery roller 22. When the spinning machine is spinning the yarn Y, the sliver 6 supplied to the draft device D via the sliver guide 5 is twisted by the twist device T after being drawn by the draft device D and forms the yarn Y. The fibers comprising the sliver 6 supplied to the air spinning nozzle 7 of the twist device T enter the insertion hole 9b of the spindle 9 from the tip 9a while being rotated by a rotating air current blown from the air blowing holes 7b and the yarn Y is produced. In this way, under normal spinning machine operating conditions, supply of the compressed air from the air blowing hole 13 stops, the suction pipe 20 operates and accordingly, normally, suction air is generated in the suction pipe 20. Next, using Figures 2 to 7, the piecing process will be described. When a yarn breakage occurs, a detection signal is generated by a detection sensor (not shown in the drawings) and in association with that, supply of the sliver 6 is stopped by stoppage of the driving of the back rollers 1 and third rollers 2 via a clutch (not shown in the drawings) connected to the back rollers 1. The twist device T continues operations as before. The tip of the sliver 6 is then immediately pulled into a tapered shape between the stationary third rollers 2 and still driving middle rollers 3. Furthermore, after a predetermined time period has elapsed, the blowing of air from the air blowing holes 7b is stopped and the operation of the twist device T stopped. Next, the piston rod 18 is advanced by movement of the cylinder 17, the spindle support member 10 separated from the nozzle block 8 and the head A' of transfer arm member A which grips by a pair of drive rollers 23, 24 the tip of the leading yarn Y' wound onto the winding package and pulled from the winding package by a publicly known suction mouth or the leading yarn Y' pulled from a package prepared for other uses, is positioned in the vicinity of the yarn exit hole 9c of the spindle 9. Additionally, a suction head 25 of an air sucker member S is positioned between the spindle support member 10 and nozzle block 8 such that the tip 9a of the spindle 9 is in the vicinity of the suction hole 26 of the suction head 25. Thereafter, a suction air current is generated in the suction hole 26 of the suction head 25 and the leading yarn Y' is inserted in the insertion hole 9b of the spindle 9 by operation of the drive rollers 23, 24 of the transfer arm member A. Then the tip of the leading yarn Y' is sucked and held in the suction head 25 of the air sucker member S (Refer to Figure 2). Next, as shown in Figure 3, the air sucker member S which holds the leading yarn Y' is lowered, the piston rod 18 is retracted by operation of the cylinder 17 and the spindle support member 10 and nozzle block 8 are coupled. Even if the spindle support member 10 and nozzle block 8 couple, the leading yarn Y' is not trapped by the walls of the spindle support member 10 and nozzle block 8 as it enters the slits 15, 16. In association with the lowering of the air sucker member S, the drive rollers 23, 24 are stopped after delivery of a predetermined amount of leading yarn Y' by operation of the drive rollers 23, 24 of the transfer arm member A. Next, an air current in the direction of the tip 9a is generated in the insertion hole 9b of the spindle 9 by supplying compressed air to the air blowing hole 13 from a compressed air supply source (not shown in the drawings) via a pipe 14. It should be noted that a suction air current is normally generated in the suction pipe 20. When the suction air current generated in the suction pipe 26 of the air sucker member S is stopped, the leading yarn Y' held in the air sucker member S is inserted in the suction pipe 20, in which is generated a suction air current, by ejection from the sliver guide entrance 7c of the air spinning nozzle 7 being the hole for guidance into the twist device T of the sliver 6, due to the air current generated in the insertion hole 9b of the spindle 9 in the direction of the tip 9a (Refer to Figure 4). After the leading yarn Y' has been inserted in the insertion hole 9b of the spindle 9 and held in the suction pipe 20, it is preferable for the supply of compressed air to the air blowing hole 13 to stop but when the compressed air blown from the air blowing holes 7b of the air spinning nozzle 7 is strong enough, even if compressed air is blown from the air blowing hole 13, there is no influence on the driving of the twist device T and the supply of compressed air to the air blowing hole 13 does not need to be stopped. It should be noted that, in this state as shown in Figure 4, it is preferable for the leading yarn Y' to be gripped by the stationary drive rollers 23, 24 of the transfer arm member A so that surplus leading yarn Y' is not fed out. However, the transfer arm member A may also be returned to a standby position by releasing the holding of the leading yarn Y' by the drive rollers 23, 24 of the transfer arm member A. While the operation of the twist device T and the blowing of air from the air blowing holes 7b are stopped, the stationary back rollers 1 and third rollers 2 are restarted and when the sliver 6 gripped by the back rollers 1 and third rollers 2 moves, the sliver 6 fed out from the front rollers 4 is inserted in the suction pipe 20. As shown in Figure 5, the leading yarn Y' ejected from the sliver guide entrance 7c of the air spinning nozzle 7 and the sliver 6 fed out from the front rollers 4 are inserted in the suction pipe 20 together. The sliver 6 is sucked into the suction pipe 20 by the continued driving of the draft device D. As described above, when the leading yarn Y' and sliver 6 drawn by the restarting of the draft device D are sucked together into the suction pipe 20, the leading yarn Y' is pulled in the direction of the winding package by the contact of the nip rollers 21 with the delivery rollers 22 and when air is blown from the air blowing holes 7b, a suction air current stronger than the suction air current of the suction pipe 20 is generated in the vicinity of the sliver guide entrance 7c of the air spinning nozzle 7 so fibers comprising the sliver 6 delivered from the front rollers 4 are guided into the sliver guide entrance 7c of the air spinning nozzle 7 and yarn piecing is performed by entangling with the leading yarn Y' in the internal part 7a of the air spinning nozzle 7 forming the piecing area. As described above, when the leading yarn Y' and sliver 6 drawn by the restarting of the draft device D are sucked together into the suction pipe 20, as the twist device T restarts, yarn piecing may be reliably performed without reliance on the pulling timing of the leading yarn Y' guided into the twist device T and the supply timing of the sliver 6 to the twist device T by the restarting of the back rollers 1 and third rollers 2. In the above described embodiment, the spindle support member 10 and nozzle block 8 are comprised so as to be separable and contactable but the spindle support member 10 comprising the twist device T and nozzle block 8 may be a single unit. In that case, after the positioning close to the yarn exit hole 9c of the spindle 9, of the head A' of the transfer arm member A which grips the leading yarn Y', an air current in the direction of the tip 9a is generated in the insertion hole 9b of the spindle 9 by the supply of compressed air to the air blowing hole 13, a suction air current Is also generated in the suction pipe 20, the leading yarn Y' is inserted in the twist device T by the operation of the drive rollers 23,24 of the transfer arm member A and ejected from the sliver guide entrance 7c of the twist device T. Accordingly, in the present embodiment, the air sucker member S may be ommitted.

Claims: Method for piecing a sliver (6) delivered by a re-operated draft device (D) and the leading yarn (Y') of a winding side yarn end ejected from a sliver guide entrance of a twist device (T) in a stationary state by holding them before the wist device (T) and introducing them into the twist device (T) characterized in that the leading yarn (Y) and the sliver (6) are both held in a suction pipe (20) located between the front rollers (4) of the draft device (D) and the twist device (T) and that after re-operating the draft device (D) the twist device (T) is operated and fibres comprising the sliver are entangled with the leading yarn (Y') pulled from the twist device (T). Piecing device for performing the method according to claim 1 having a means for inserting the leading yarn (Y') into the twist device (T) in the stationary state and a suction pipe (20) characterized by a suction pipe (20) adapted to suck and hold the leading yarn (Y') ejected from the sliver guide entrance of the twist device (T) in the stationary state and the sliver (6) delivered by the restarted draft device (D) and that said suction pipe (20) is located between the front rollers (4) of the draft device (D) and the twist device (T).

Inventors: HIRAO OSAMU, NISHIMURA MASAHIKO, HIRAO, OSAMU, NISHIMURA, MASAHIKO
Applicants: MURATA MACHINERY LTD, MURATA KIKAI KABUSHIKI KAISHA
Application year: 1997
Main classification: D01H5
IPC codes: D01H15