Threading bushes
United States Patent 1 Benyon THREADING BUSHES [75] Inventor: John Benyon, Astley, near Bolton,  
 Lancashire, England [73] Assignee: Platt International Limited, Oldham,  
 Lancashire, England [22] Filed: Jan. 19, i973 [21] Appl. No: 325,040  
 [58] Field of Search 57/34 R, 51.5, 77.33, 77.4, 57/106, 156, 157 R, 157 TS; 226/9l, 92  
 [56] References Cited UNITED STATES PATENTS 3,066,473 12/1962 Maeda 57/77.4 3,373,553 3/1968 Naumunn.... 57/77.3  
 10/1970 Tsuruta et al 57/77.4 X 9/l97l Guigward et al, 57/l06 Primary E.raminerDonald E. Watkins [57] ABSTRACT The threading ofa running yarn through a pair of twist bushes in a textile machine for processing continuous synthetic filament, said bushes being situated side by side with their axes mutually parallel and with the first bush having an entrance facing one direction and an exit facing in the opposite direction. and the second bush having an exit facing in said one direction and an entrance facing in said opposite direction is achieved as follows. A yarn passage is provided which extends between the entrance of the first bush and the entrance of the second bush and an airflow is caused which passes through the yarn passage and the bushes in a direction progressing from the entrance of the first bush to the entrance of the second bush, therehy drawing a running yarn in the vicinity of the entrance of the first bush through both bushes.  
 23 Claims, 9 Drawing Figures PATENTEB 81975 SHLU 1 OF 3 PATENIEDAPR 1ers SdEET 3 [IF 3 THREADING BUSHES The present invention relates to a method of an apparatus for threading yarn through twist bushes. for example in texturing machines for texturing continuous synthetic filament yarn by the application of false twist to the running yarn by means of the twist bushes.  
  The drive systems in known texturing machines are provided with a crawl speed ratio to permit a broken end or a new end of yarn to be threaded through the twist bush assembly by hand.  
  In machines of this type extruded filament is drawn and delivered to the twist bush assembly in one continuous operation. Thus the twist bushes must be threaded with yarn the delivery of which cannot be interrupted or decreased to a crawl speed. It is known to handle running yarn in synthetic filament processing machinery by an aspirator gun but an operative cannot safely handle the filament entering the gun and threading the bushes is difficult.  
  The present invention seeks to provide a method of an apparatus for facilitating the threading procedure.  
  According to a first aspect of the present invention there is provided a method of threading running yarn through a pair of twist bushes in a textile machine for processing continuous synthetic filament, said bushes being situated side by side with their axes mutually parallel and with the first bush having an entrance facing in one direction and an exit facing in the opposite direction and the second bush having an exit facing in said one direction and an entrance facing in said opposite direction, the method comprising providing a yarn passage extending between the exit of the first bush and the entrance of the second bush and causing airflow through the yarn passage and the bushes in a direction progressing from the entrance of the first bush to the exit of the second bush. thereby drawing a running yarn in the vicinity of the entrance of the first bush through both bushes.  
  A third bush may be provided in the textile machine, the third twist bush being disposed in the same relation to the second twist bush as the first twist bush is to the second twist bush. in this case, the method comprises providing a further yarn passage extending between the exit of the second bush and the entrance of the third bush and causing an airflow through the firstmentioned yarn passage and the further yarn passage and the three bushes in a direction progressing from the entrance of the first bush to the exit of the third bush, thereby drawing a running yarn in the vicinity of the entrance of the first bush through both bushes.  
  According to a second aspect of the present invention threading apparatus comprises a pair of twist bushes situated side by side with their axes mutually parallel and with the first bush having an entrance facing in one direction and an exit facing in the opposite direction and the second bush having an exit facing in said one direction and an entrance facing in said opposite direction. and means providing a passage, for interconnecting the exit of the first bush and the entrance of the second bush, whereby the provision of an airflow which progresses through the first bush, the passage and the second bush draws a running yarn in the vicinity of the entrance to the first bush through both the bushes.  
  Two embodiments of yarn threading apparatus according to the invention will now be described by way of example with reference to the accompanying drawings, in which:  
  FIG. I shows a front elevation ofa yarn texturing station of a draw texturing machine.  
  FIGS. 2 to 6 shows cross-sectional views of a first embodiment of yarn threading apparatus including two twist bushes at successive stages in a threading operation, and  
  FIG. 7 is a perspective view of a yarn tube of the apparatus.  
  FIG. 8 shows a modified form of the first embodiment of the yarn threading apparatus including three twist bushes.  
  FIG. 9 is a cross-sectional view of a second embodiment of yarn threading apparatus.  
  The yarn texturing station of FIG. 1 is typical of one of 148 yarn texturing stations of a draw texturing machine. Each station is fed with filament by a corresponding one of I48 filament extruders and has a pair of twist bushes 8. 10 (as described in our co-pending application No. 31922/71) mounted in a frame 7, for imparting false twist to the filament handled by the station. The twist bushes 8, 10 are driven by a belt 9 which also passes around a tensioning jockey pulley I1 and and a driving motor 15.  
  Referring to FIGS. 2 to 7, in the first embodiment the two bushes 8 and I0 are situated side by side with their axes mutually parallel and with the upper bush 8 having an entrance 13 facing in one direction and an exit 14 facing in the opposite direction and the lower bush I0 having an exit 20 facing in said one direction and an entrance IS in said opposite direction. Running filament 2 delivered by a yarn feed device on the machine (not shown) is threaded through the bushes 8, 10 in the following manner. As shown in FIG. 2, the running yarn 2 is initially fed continuously into a suction nozzle 4 where it passes to waste. A U-shaped plastics tube 6 is mounted permanently behind the bushes 8 and 10 with its inlet 12 in register with the exit 14 of the upper bush 8 and its outlet 16 in register with the entrance I8 of the lower bush 10. When the nozzle 4 is moved close to the exit 20 of the lower bush 10 so that the nozzle 4 is generally in the same plane as the entrance I3 of the first bush, air and entrained yarn is induced to enter the upper bush 8 (as shown in FIG. 3) and then to pass around the tube 6 (as shown in FIG. 4) and into the nozzle 4. Thus the yarn forms a loop one leg 22 (as shown in FIG. 4) of which consists of running filament the other 24 consisting of stationary yarn held by the nozzle 4. The loop 22 then enters the nozzle 4 which can be withdrawn from the bushes (as shown in FIG. 5). The stationary leg 24 of yarn is then cut at the position identified as X in FIG. 5, leaving the yarn 2 threaded through the bushes 8 and 10. The stationary leg 24 of the yarn may be cut just before the loop leaves the exit 20 of the second bush 10.  
  The filament 2 is then threaded around the next filament feed device and the tension imposed upon the filament draws it through a continuous vertical slit 26 in the tube 6 (as shown in FIG. 7) so that the filament 2 is drawn out of the tube 6 and makes full contact with the bushes 8 and 10 (as shown in FIG. 6).  
  As shown in broken line in FIG. 2, the suction nozzle 4 may be connected to tube 6 so that, in use, the nozzle 4 can be offered up to the bushes 8, 10 with the tube 6 behind the bushes 8, 10 so that when the nozzle 4 is rotated axially the inlet 12 and the outlet 16 of the tube 6 register with the exit 14 of the first bush 8 and the entrance 18 to the second bush 10 respectively.  
  The embodiment shown in FIGS. 2 to 7 may be modified as shown in FIG. 8, with parts common to FIGS. 2 to 7 and to FIG. 8 bearing the same reference numerals. This modification comprises three twist bushes 8, i0, 25 with all three bushes arranged sideby-side with their axes parallel. The first and second bushes 8, 10 are as described above with reference to the FIGS. 2 to 7 and the third bush 25 has an entrance end 27 facing in said one direction and an exit end 29 facing in the said other direction. A second tube 30 of similar construction to the first tube 6 connects the exit 20 of the second bush 10 with the entrance 27 of the third bush 25.  
  To thread the bushes 8, 10 25 the suction nozzle 4 is placed close to the exit 29 of the third bush 25 and a running yarn 2 held in the vicinity of the entrance 13 to the first bush 8 by a second suction nozzle (not shown) in the manner described above with reference to FIGS. 2 to 7 is drawn in a loop in to the first bush 8. The loop then passes through the first tube 4, the second bush 10, the second tube 30 and the third bush 25 before entering the suction nozzle 4. The stationary arm of the loop of yarn 2 is then severed adjacent the entrance 13 of the first bush to complete the threading operation. The second suction nozzle may be switched off or removed as soon as the loop of yarn 2 enters the first bush 8.  
  A second embodiment of yarn threading apparatus is shown in FIG. 9 with parts common to FIGS. 2 to 7 and FIG 9 bearing the same reference numerals. In this embodiment the suction nozzle 4 is replaced by an inlet 21 in the tube 6 which is co-axial with the second bush l and is connected to a source of air under pressure through a valve 23. To piece up a running yarn 2 in the vicinity of the entrance 13 to the first bush 8 the valve 23 is opened and a blast of compressed air directed through the second bush from the entrance 18 to the exit thereof. This causes an associated airflow to progress through the first bush 8 and the tube 6 and the running yarn 2 forms a loop which enters the entrance 13 of the first bush 8, passes around the tube 6 and through the second bush 10 to leave through the exit 20 of the second bush 10. The stationary arm of the loop can then be severed to leave the bushes 8, l0 threaded.  
  In the embodiment described above with reference to FIG. 8. the suction nozzle 4 may be replaced by an inlet (not shown) of the type described with reference to FIG. 9 located in the second tube 30. In this arrangement the blast of compressed air produces an airflow in the bushes 8, 10, 25 and the tubes 6, which is greater than the suction of the second suction nozzle so that the yarn 2 is drawn into the first bush 8 in a loop I claim:  
  1. A method of threading running yarn through a pair of twist bushes in a textile machine for processing continuous synthetic filament, said bushes being situated side by side with their axes mutually parallel and with the first bush having an entrance facing one direction and an exit facing in the opposite direction, and the second bush having an exit facing in said one direction and an entrance facing in said opposite direction, the method comprising providing a yarn passage extending between the exit of the first bush and the entrance of the second bush and causing airflow through the yarn passage and the bushes in a direction progressing from the entrance of the first bush to the entrance of the second bush, thereby drawing a running yarn in the vicinity of the entrance of the first bush through both bushes.  
  2. A method according to claim 1 wherein the airflow through the yarn passage is produced by applying suction to the exit of the second bush.  
  3. A method according to claim 2 wherein the suction is produced by a portable suction nozzle.  
  4. A method according to claim 3 and further comprising the step of passing the running yarn to waste through the suction nozzle prior to the application of suction to the exit of the second bush.  
  5. A method according to claim 4 wherein the yarn is arranged in the vicinity of the entrance of the first bush just prior to threading, by locating the suction nozzle in generally the same plane as the entrance of the first bush and the exit of the second bush.  
  6. A method according to claim 4 wherein the application of suction to the exit of the second bush causes a loop of the running yarn to be drawn into the entrance of the first bush, to pass along the yarn passage, and to pass through the second bush to be taken-up by the suction nozzle and wherein one arm of the loop is so severed as to leave the running yarn threaded through the bushes 7. A method according to claim 6 wherein the yarn connection with the suction nozzle is severed after the loop leaves the exit of the second bush.  
  8. A method according to claim 6 wherein the yarn connection with the suction nozzle is severed just before the loop leaves the exit of the second bush.  
  9. A method according to claim 1 wherein the airflow through the yarn passage is produced by a blast of compressed air admitted into the passage from an inlet in the passage in such a direction that a running yarn in the vicinity of the entrance of the first bush is drawn through both bushes.  
  10. A method according to claim 7 wherein the blast of compressed air is directed such that it passes through the second bush from the exit end thereof to the entrance thereof.  
  ll. A method according to claim 1 and further comprising removing the yarn passage after threading has been accomplished.  
  12. A method according to claim 1 and further comprising retaining the yarn passage in position after the yarn has been threaded through the bushes and then tensioning the yarn after threading to cause it to escape from the passage through a continuous slit therein thereby to enable the yarn to contact twisting surfaces of the bushes.  
  13. A method according to claim 1 and in which a third twist bush is provided in the textile machine, the third twist bush being disposed in the same relation to the second twist bush as the first twist bush is to the second twist bush, the method comprising providing a further yarn passage extending between the exit of the second bush and the entrance of the third bush and causing an airflow through the first-mentioned yarn passage and the further yarn passage and the three bushes in a direction progressing from the entrance of the first bush to the exit of the third bush, thereby drawing a running yarn in the vicinity of the entrance of the first bush through both bushes.  
  14. A threading apparatus comprising a pair of twist bushes situated side by side with their axes mutually parallel and with the first bush having an entrance facing in one direction and an exit facing in the opposite direction and the second bush having an exit facing in said one direction and an entrance facing in said oppposite direction, and means providing a passage for interconnecting the exit of the first bush and the entrance of the second bush. whereby the provision of an airflow which progresses through the first bush, the passage and the second bush draws a running yarn in the vicinity of the entrance to the first bush through both bushes.  
  15. Apparatus according to claim 14 wherein the passage is defined by tube having an inlet for registering with the exit of the first bush and an outlet for registering with the entrance of the second bush.  
  [6. Apparatus according to claim 15 wherein the tube has a continuous slit which extends from the inlet to the outlet and which is so dimensioned and disposed as to allow yarn to pass through it but does not cause a sufficient pressure drop in the tube as to adversely affect the airflow during threading 17. Apparatus according to claim 16 wherein the tube is of circular cross-section and is arcuately bent with the slit extending along the line of shortest arc length between the inlet and the outlet.  
  l8. Apparatus according to claim 14 wherein the tube is mounted permanently behind the pair of bushes with its inlet in register with the exit of the first bush and its outlet in register with the entrance of the second bush.  
  19. Apparatus according to claim 15 wherein there is provided an inlet in the tube for admitting a blast of compressed air into the tube in such a direction that a running yarn in the vicinity of the entrance of the first bush is drawn through both bushes.  
  20. Apparatus according to claim 19 wherein the inlet has an axis co-axial with the axis of the second bush so that the blast of compressed air passes through the second bush from the entrance to the exit thereof.  
  21. Apparatus according to claim 14 and further comprising a suction nozzle which, in use, is applied to the exit of the second bush to cause said airflow through the passage and the bushes.  
  22. Apparatus according to claim 21 wherein the yarn tube is connected to the suction nozzle so that, in use, the nozzle can be offered up to the bushes so that the nozzle is then in front of the bushes whilst the tube fits behind the bushes so that when the nozzle is rotated axially, the inlet and the outlet of the tube register with the exit of the first bush and the entrance to the second bush respectively.  
  23. Apparatus according to claim 14 wherein the yarn tube is portable so that it may be transferred from one pair of bushes to another pair of bushes by an operative.