US3693899A

US3693899A - Thread guiding means for yarn winding

Info

Publication number: US3693899A
Application number: US65296A
Authority: US
Inventors: John Leslie Burgess; Joseph Eric Harvey
Original assignee: Maxam Power Ltd
Current assignee: Maxam Power Ltd
Priority date: 1970-06-22
Filing date: 1970-08-19
Publication date: 1972-09-26
Anticipated expiration: 1989-09-26

Abstract

A thread guide for a yarn winding machine, which comprises a reciprocating shuttle slidably mounted on a fixed track and means for subjecting the shuttle to timed blasts of compressed air to cause its reciprocating movement along the track. The shuttle is a double-acting cylinder member having opposed open-ended cylinders which cooperate with fixed pistons mounted in adjustable positions at opposite ends of the track. The fixed pistons contain poppet valves arranged to be actuated by the engagement of the shuttle with their actuating members at the ends of the reciprocating movements of the shuttle along the track. Each actuating member protrudes from the crown of one of the fixed pistons for engagement by the end wall of the opposed cylinder of the shuttle and when so engaged opens the valve to deliver a blast of compressed air into the cylinder to propel the shuttle in the reverse direction along the track.

Description

United. States Patent Burgess et al.

- June 22, I970 THREAD GUIDING MEANS FOR YARN WINDING lnventors: John Leslie Burgess, Penzance,

Cornwall; Joseph Eric Harvey, Camborne, Cornwall, both of England Assignee: Maxam Power Limited, Camborne,

Cornwall, England Filed: Aug. 19, 1970 Appl. No.: 65,296

Foreign Application Priority Data Great Britain ..30,207/70 US. Cl. ..242/43, 242/1 8.1, 242/43.l

Int. Cl. ..B65h 54/28 Field of Search ..242/43,. 43.1, 18.1

References Cited UNITED STATES PATENTS Dyer et al. ..242/43 Dyer ..242/43 Dyer ..242/43 Emerson ..242/43 1451 Sept. 26, 1972 3,1 18,628 l/l964 Lacasse ..242/43 Primary Examiner-Stanley N. Gilreath Attorney-Watson, Cole, Grindle & Watson 57] ABSTRACT A thread guide for a yarn winding machine, which comprises a reciprocating shuttle slidably mounted on a fixed track and means for subjecting the shuttle to timed blasts of compressed air to cause its reciprocating movement along the track. The shuttle is a doubleacting cylinder member having opposed open-ended cylinders which cooperate with fixed pistons mounted in adjustable positions at opposite ends of the track. The fixed pistons contain poppet valves arranged to be actuated by the engagement of the shuttle with their actuating members at the ends of the reciprocating movements of the shuttle along the track. Each actuating member protrudes from the crown of one of the fixed pistons for engagement by the end wall of the opposed cylinder of the shuttle and when so engaged opens the valve to deliver a blast of compressed air into the cylinder to propel the shuttle in the reverse direction along the track.

14 Claims, 4 Drawing Figures SHEET 1 OF 4 PATENTEDSWB I972 INVENTORS LESLIE Bukasss Em: HAaveY BY M Mw ATTORNEY PATENTED SEP 26 I972 SHEET 3 [IF 4 Wm vv mv B mm R INVENTORS LEN-E Bulzecss ATTORNEY THREAD GUIDING IWEAN S FOR YARN WINDING This invention relatesv to machines for winding yarn on,a rotating spool or bobbin, and is concerned with providing such machines with an improved form of thread guiding means.

In the conventional winding of yarn'on a spool or bobbin, the thread is wound in layers each comprising an extremely coarse helix, to form a so-called package on the spool, the thread being'guided onto the spool during the winding by a mechanically driven cam-controlled reciprocating guide arm which guides the-thread along the axial length of the spool and back again as the spool rotates. The speed at which such yarn winding machines can work is limited by the maximum speed at which the cam-operated thread guide can be reciprocated, the practical limit at present being 600-700 complete cycles per minute, i.e., l,200-l-,400 one-way strokes per minute. Moreover, when such purely mechanical thread transporting mechanisms are run at high speed, very considerable stresses arise due to the high accelerations and decelerations involved in the rapidreversals of direction of the moving parts, so

that mechanical wear is considerable.

One object of the present invention is to provide a yarn-winding machine having a thread guide which can be reciprocated at much higher speeds than this without excessive wear, and which is readily adjustable to vary the length of stroke, for example during the act ual high-speed winding operation, to suit the particular size or shape of wound package required.

According to the present invention, a high-speed pneumatic traverse for leading yarn on to a rotary takeup spool of a yarn-winding machine while reciprocating the yarn transversely across the face of the spool, comprises a linear track extending across the face of the take-up spool, a linearly-reciprocable shuttle slidably mounted on the track for reciprocating movement along the track, a thread guide carried by the shuttle,

means for applying compressed air alternately to opposite ends of the shuttle to propel the shuttle pneumatically along the track in successively reversed reciprocation strokes, which means comprises a pair of valve housings respectively mounted at opposite ends of the track, means for connecting both valve housings to a supply of compressed air, a pneumatic control valve in each valve housing, each control valve being biassed to a closed position and having an actuating member positioned to be actuated by the moving shuttle approaching the respective valve housing toward the end of a reciprocating stroke, the actuating member when so actuated opening the control valve to release a blast of compressed air which reverses the direction of motion of the shuttle and propels the shuttle along the track in its next-succeeding reciprocation stroke, and in which each valve housing is mounted for movement along the length of track during the operation of the traverse device, and which includes a strokeadjusting mechanism coupled to both valve housings and operable to move both valve housings progressively toward-one another along a track at a controlled rate during the reciprocating motion of the shuttle so as to reduce the stroke length of the shuttle progressively during the operation of the winding machine.

In one form of the invention, the stroke-adjusting mechanism comprises an actuator member and a pair of driving mechanisms respectively coupled between said actuator member and the respective valve housings whereby movement of the said actuator member in a given direction causes the two valve housings to be moved toward one another along the track.

A further object of the invention is to provide means for breaking the pattern of the yarn on the winding as the latter builds up progressively on the take-up spool, and for this purpose means is provided for rapidly shifting the position of each of the valve housings along-the track at intervals during the winding operation for pattem-breaking purposes, the said pattern-breaking means overriding the actuation of the stroke-adjusting mechanism, and preferably comprising a motor-driven rotary cam mechanism coupled to both of the said valve housings.

A still further object of the invention is to provide an improved construction of control valve in each valve housing of the traverse device. For this purpose each valve housing and the associated end of the shuttle may be constructed and arranged to telescope one within the other as a free-fitting piston-and-cylinder mechanism, and to enclose a space between them when so telescoped, the control valve when opened delivering compressed air into said enclosed space to act on the end of the shuttle, and each control valve may have a valve seating and a cooperating movable valve plunger aligned with the track, the plunger being formed with opposed piston faces respectively subject to oppositely directed differentially acting nearly balanced pressure thrusts by the compressed air supply connected to the valve housing and being biassed to its closed position in engagement with the valve seating, and an end portion of the plunger protruding from the valve housing toward the other valve housing and constituting the actuating member for engagement by the shuttle, whereby the initial engagement of said protruding end of the plunger by the shuttle partially opens the valve to deliver compressed air to said enclosed space between the telescoped valve block and shuttle end, whereupon the pressure of the compressed air delivered into said enclosed space acts on said protruding end of the plunger to open the valve fully. Thus when the control valve is cracked open by the engagement of the shuttle at the end of its approach stroke, the air delivered through the partially opened valve and acting on the shuttle to reverse its direction of motion will be at high pressure, and this high air pressure acting on the plunger of the poppet valve will at once fully open the valve. When the shuttle has reversed its travel and has been propelled in the opposite direction by the air pressure into its succeeding stroke, the pressure of air delivered through the open poppet valve will fall to atmospheric pressure, and the poppet valve will be reclosed by its closing spring.

In one arrangement of the invention the shuttle is slidably mounted between rigid elongated parallel guides having the fixed piston positioned between them. For example the parallel guides may comprise rods threaded through apertures in opposite sides of the shuttle, so that the shuttle can slide along the rods between which it is suspended. Alternatively, the guides may comprise a pair of spaced parallel inwardly facing channel guides of part-circular or other internal cross-section corresponding to the external cross-sec- 3 tional profile of the shuttle, the shuttle being slidably mounted in the opposed channels of the two guides.

The invention may be carried into practice in various ways but one specific embodiment and a modification thereof will now be described by way of example only and withzreference to the accompanying drawings, in which g t FIG."1 is an end elevation of ayarn winding machine,

FIG. 2 is a plan'view of the machine of FIG. 1 with certain parts omitted for the sake of clarity,

FIG. 3 is a detailedview, partly sectioned and on a larger scale, of the thread guide means for the winding machine of FIGS. 1 and 2, and v I FIG. 4 is a perspective view of a modified construction of a thread guide means.

Y The winding machine of FIGS. 1 and 2 comprises a frame on which a take-'upspool or former 11 fora winding package 12 isjournalled in end bearings 13. The'package 12,"which is shown partly wound in FIG. 1, is driven at a constant peripheral speed by means of a friction roller 14 journalled on one end of an arm 15 whose other end is pivoted at 16 to the frame 10, the roller 14 being'driven by a belt drive 17 from an electric motor 18. The friction roller 14 can pivot on the 15 as the diameterof the package 12 grows during the winding process, from-a starting position shown in broken lines in FIG. 1' to the intermediate position shown in firm lines, and beyond, so that the peripheral speed of the rotating package 12 will remain in constant ratio to the speed of the driving motor 18 despite the changing radius of the package. The driving roller 14, arm 15, belt drive 17 and. motor 18 and the frame 10, have all been omitted from FIG. 2 for the sake of clarity. Y Y

The yarn 20 for windingon the package-is led down vertically from an overhead supply (notshown) and is guided onto the package 12 by the reciprocating forked guide plate 21 of a thread guide mechanism which is generally indicated at 22 and is shown in detail in FIG. 3. The thread guide mechanism 22 is mounted on the upper edge of a swinging frame 23 pivoted to the frame 10 at 24. The'swinging frame 23 carries an elongated roller 25 which holds the vertical yarn 20 against the package during winding-the pressure of the yarn on the roller 25 swinging the frame 23 and the guide mechanism 22 outwardly as the radius of the package grows during the winding.

The thread guide shown in detail in FIG. 3 comprises a shuttle 30 slidably mounted for reciprocating motion along a pair of spaced

parallel guide rods

31, 31 secured across the arms 23A of the swinging frame 23 and tensioned by means of nuts 33. The shuttle 30 comprises a double-acting cylinder member whose two coaxial cylinders 35 have their open ends facing outwardly at opposite ends of the shuttle and are both closed at their inner ends by walls 36. The shuttle 30 carries the thread guide plate 21 in which is inset a thread guide 37 made of some hard sintered material such as aluminum oxide.

The shuttle cylinders 35 co-operate respectively with a pair of fixed but longitudinally-adjustable pistons 38 formed as projecting bosses on the ends of a pair of spaced housings 39 each of which is slidably mounted on the guide rods 31 and is carried on one end of a backing rod 40. Each housing 39 has a cylindrical bore in whicha valve plunger 41 is a close sliding fit, the plunger 41' forming the movable valvemember of a poppet valve. The head 43 of the poppet valve plunger 41 carries a sealing ring 44 which co-operates with a valve seating formed on an inturned flange 45 at the inner end of the piston 38, and a light spring 46 acting on the rear end of the valve plunger 41 tends to hold the poppet valve seal 44 in sealing engagement with the seating to close the poppet valve. An actuating button 48 on the other end of the plunger 41 protrudes through the aperture defined by the flange 45 and can be depressed to open the poppet valve. Compressed air is admitted through a pipe 50 into the bore of the housing.39 and into an annular groove 51 in the plunger 41 so as to be retained by the poppet valve seal 44 when the valve is closed. The compressed air can pass through axial'grooves 52 in a land 53 on the valve plunger 41' so as to reach the head 43 of the plunger. The effective face area of thepiston face constituted by the land 53 is slightly larger than the effective face area of the poppet valve head 43, so that the differential pressure of compressed air admitted through the pipe 50 would openthe poppet valve but for. the spring 46, which holds the valve lightly closed with the valve seal 44 engaging the valve-seat on the flange 45. A very small force exerted on the actuatingbutton 48 however will overcome the spring 46 and open the poppet valve. The housing 39 is formed with a vent 54 leading from its bore behind the plunger 41 to relieve pressure behind the plunger due to any leakage of compressed air past the plunger.

Each shuttle cylinder 35 is a loose fit around the associated piston 38, the radial clearance being 0.l mm approximately, which is sufficient to eliminate cushioning of the shuttle by air trapped between the piston 38 and cylinder 35, and to eliminate piston/cylinder wear almost entirely as no actual contact is made between the cylindrical surfaces of the pistons andcylinders. The axial projection of each actuating button 48 beyond the crown of the associated piston 38 is very small, for exampleO.5 mm., so that when the shuttle 30 reaches the end of its stroke the engagement of the inner end wall36 of onecylinder 35 with the actuating button 48 protruding from the piston 38 which has entered that cylinder is sufficient to open the poppet valve very slightly.

The operation of the mechanism will now be described from that point onwards. When the poppet valve has been cracked open by this depression of the actuating-button 48 by the shuttle 30 at the end of one stroke, compressed air supplied from the pipe 50 passes through the grooves 52 and escapes past the seal 44 of the slightly open poppet valve into the shuttle cylinder 35 to act on the shuttle 30. The pressure of the compressed air trappedin the cylinder 35 acts on the full effective face area of the piston land 53 and the end of the plunger 41 and immediately forces the poppet valve plunger 41- right back off its seat on the flange 45 to open the valve fully, enabling a full flow of compressed air from the supply pipe 50 to enter the cylinder 35 and to act on the shuttle 30, to stop the forward travel of the shuttle and to accelerate it rapidly in the opposite direction. As soon as the cylinder 35 clears the piston 38 in an early stage of the reversed travel of the shuttle 30, the air pressure acting on the plunger 41 to hold the poppet valve open will drop to atmospheric pressure, allowing the poppet valve to be closed by the spring 46.

- The shuttle continues to travel along the guide rails '31 for a further complete stroke, until it reaches the piston 38 at the opposite end of the rails 31 and actuates the button 48 of that piston to open the associated poppet valve and initiate a further reversal of travel of the shuttle. In this way the cycle of movement of the shuttle 30 is completed and continuous reciprocating motion of the shuttle along the guide rails is maintained,'the operation of the poppet valves which control the supply of compressed air being automatically synchronized with the movement of the shuttle by virtue of the fact that the shuttle itself initiates the opening of the poppet valves.

' To start the reciprocating movement of the shuttle 30, the shuttle is flicked manually against the actuating button 48 of one or other of the fixed pistons 38, thereby cracking open the associated poppet valve to initiate the compressed air: supply. Thereafter the reciprocation continues automatically.

Thelength of stroke of the shuttle is determined by the spacing between the actuating buttons v48 of the two fixed pistons 38. This spacing can be adjusted by means of a slow stroke-reducing mechanism including .a'pair of spaced cams 60 shown in FIG. 2,-whose cam followers 61 are mounted on the ends of the backing rods 40. The cams 60(which are omitted from FIG. 1 for the sake of clarity) are slidably mounted on guide rods 62 carried by the fixed journal bearings 13 for the take-up spool 11. The backs 63 of the cams 60 are plane, and are engaged by adjustable stops 64 each of which when in a given position of adjustment bears against the back 63 of the associated cam 60 to hold the cam in a given position on its guide rod 62. As the winding process proceeds and the radius of the package 12 grows, the engagement of the guide roller 25 with the periphery of the" growing package progressively swings the pivotedframe 23 outwardly so 'as to move the-whole thread guide mechanism 22 on theframe 23 transversely to its length in the direction away from the take-up spool 11. This movement causesthe two cam followerrollers-61 on the backing rods 40 to traverse the profiles of the cams 60 whereby the backing rods 40 are slowly and progressively cammed towards one another, sliding through the ends 23A of the frame 23 as the winding proceeds. This movement of the backing rods 40 produces a corresponding movement towards one another at a controlled rate of the housings 39,

slidingalong the guide rods 31 whereby the spacing between the fixed pistons 38 and hence the stroke of the shuttle reciprocation are slowly and progressively reduced, at a controlled rate, in order to produce the required tapered ends. of the package of yarn being wound. t I

A periodic abrupt shortening of the shuttle stroke can also be superimposed on the slow stroke reduction for the purpose known as pattern breaking- Such abrupt stroke shortening is produced by means of a further'cam 70 which is mounted on the vertical shaft of a gear box 71 driven by means of an electric motor 72, the gtiar box and motor being mounted on the main frame 10 behind the swinging frame 23. The cam 70 acts on apairof cam followers 73each mounted on a piston 74 slidable in a horizontal tubular guide sleeve 75 above the gear box 71, each cam follower 73 projecting downwardly through a longitudinal slot in the lower wall of the guide sleeve 75. Each piston 74 is secured to the central sliding core 76 of one of a pair of flexible control cables 77 which extend between the ends of the guide sleeve 75 and-the ends of the thread guide mechanism and are coupled to the movable stop plungers 64. Thus the rotation of the cam; by the motor 72 (which may be controlled in synchronism with the winding motor 18) periodically transmits the inward motion through each flexible cable 77 to the associated stop plunger 64,v by which motion the associated cam 60 is abruptly moved inwardly above the guide rod 62 to shorten the stroke of the shuttle 30 at that end of the mechanism, thereby ensuring a change in the lay of the turns of yarn in the winding of the package and achieving the required pattern breaking.

The movable stop plungers 64 are mounted in bores formed in a pair of brackets 78 to which the ends of the outer sleeves of the flexible cables 77 are connected. Each bracket 78 is slidably mounted for movement along a slideway formed in the back of the frame 23 and can be .clamped in a required position by means of bolts 79. Thus for effecting a preliminary adjustment of the basic stroke length of the shuttle upon which the automatic variation produced by the

cams

60 and 70 will be imposed, the brackets 78 can be moved individually along the slideway of the frame 23 to suitable positions at a required spacing, and secured in these positions of adjustment by means of the bolts 79.

It will be understood that slow stroke-adjustment cams and pattern-breaking cams similar to the

cams

60 and 70 are provided in conventional yarn winding machines already in use with conventional mechanically-driven thread guides.

l-lowever, the arrangement described and illustrated enables these two stroke-shortening movements to be imposed on the pneumatically'driven thread transport means of the present invention while the latter is being driven at very high speeds of reciprocation, whereby packages with tapered ends can be wound at high speed, which was not possible with the known machine having mechanically driven thread guide arrangements. This is particularly important where the yarn being wound is a heat-processed thermoplastic material which tends to swell after winding, and if wound in straight-ended packages tends to fall off the ends of the package.

The arrangement also provides very accurate control of stroke length and of the position of the shuttle 30 when stationary at the end of each stroke, by virtue of the very short length of each actuating button 48 protruding from its piston 38, ensuring accurate cracking of the poppet valves followed by automatic full opening of the valves by the resultant pneumatic delivery pressure. Location of the end points of shuttle travel of the order of accuracy of i 0.2 mm can be obtained without difficulty.

The substantial piston/cylinder clearance of approximately 0.1 mm all round also contributes to accuracy of these end points, by eliminating cushioning of the shuttle by trapped air, and this increased clearance eliminates wear at the piston/cylinder interface and increases the useful life of the shuttle.

As the thread guide device is self-synchronizing, stroke reduction can be achieved with absolute reliability and without risk of stalling the reciprocation of the shuttle, and the improved synchronization enables the device to operate reliably on a low air pressure for a givenspeed of reciprocation, thereby reducing noise and consumption of compressed air. An almost constant helix angle is maintained during winding at constant linear yarn speed so that the circumferential velocity/transverse velocity ratio remains practically constant as the package grows. This helps to produce a stable package of good appearance. a In a modification of thread guide mechanism 22A illustrated in FIG. 4, the shuttle 30A instead of being slidably mounted on two spaced parallel guide rails, is

slidably mounted between two spaced parallel inwardly facing

elongated channel'guides

71A and 72A of semicircular or other convenient internal cross-section. One channel guide 7lA-is constructed and arranged so as to be easily disconnected and lifted off, to allow the rapid replacement of the, shuttle 30A. The valve housings 39A are similarly slidably mounted, between the two channel members, and other parts of the mechanism are similar in their construction and'operation to those of the preceding embodiment, and are identified in FIG; 4 by the same reference numerals distinguished by thesuffixA.'. v I The thread guide mechanism 22A would be substituted for the mechanism 22 in a winding machine as shown in FIGS. 1 and 2. What we claim as our invention and desire to secure by Letters Patent is: I

I l. A high-speed pneumatic traverse device'for leading yarn on to arotary take-up spool of a yam-winding machine by reciprocating the yarn transversely across the face of the spool, which comprisesa linear track extending across the' face'of the take-up spool, a linearly reciprocable shuttle slidably mounted'on the track for reciprocating movement therealong, a thread guide carried by the shuttle, means for applying compressed 2. A pneumatic traverse device as claimed in claim 1 in which the stroke-adjusting mechanism comprises a control member and a pair of driving mechanisms respectively coupled to the valve housings whereby movement of said control member in a given direction causes the two valve housings to be moved toward one another along the track.

3. A pneumatic traverse device as claimed in claim 2 including means for moving said control memberautomatically in response to the increase in radius of a packageof yarn being wound on the take-up spool, whereby the two valve housings are moved toward one another proportionately to the increase in radius to form a package with tapering ends.

' 4. A pneumatic traverse device as claimed in claim 3 in which the track is mounted on a carrier pivotally mounted for movement toward and away from the take-up spool, and which includes a roller carried by the carrier for engagement with the external surface of the package of yarn being wound on the take-up spool,

' whereby the carrier is moved angularly relatively to the take-up spool in relation upon the increase in radius of air alternately to opposite endsof the shuttle to propel v moving shuttle approaching the respective valve housing towards the end of a reciprocating stroke, the actuating member when so actuated opening the control valve to release a blast of compressed air which reverses the direction of motion of the shuttle and propels the shuttle along the track in its next-succeeding reciprocation stroke, and in which each valve housing is mounted for movement along the length of the track during the operation of the traverse device, and which includes a stroke-adjusting mechanism coupled to both valve housings and operable to move both valve housings progressively toward one another along the track at a controlled rated during the reciprocating motion of the shuttle so as'to reduce the stroke length of the shuttle progressively during the operation of the winding machine.

thepackage, the carrier constituting said control member.

5. A pneumatic traverse device as claimed in claim 4 in which each said driving mechanism comprises a cam,

and a cam follower coupled to the associated valve housing.

6. A pneumatic traverse device as claimed in claim 5 in which said cams comprise a pair of edge cams, each attached to a support for the take-up spool, and in which each said driving mechanism also includes a follower roller carried bythe associated valve housing, and. an adjustably mounted backing member, each edge cam being interposed between the associated follower roller and backing member and camming the valve housing away from the backing member and toward the other valve housing as the carrier is moved angularly away from the take-up spool.

7. A pneumatic traverse device as claimed in claim 6 in which the two'edgecams are both slidable on the support for the take-up spool in a direction parallel to the length of the track, and which includes patternbreaking means for rapidly moving one of the adjustably-mounted backing members through a short distance in a direction parallel to the length of the track to effect a rapid shifting of the associated edge cam and valve housing for pattern-breaking purposes.

8. A pneumatic traverse device as claimed in claim 1 including pattern-breaking means for rapidly shifting the position of each of the valve housings along the track at intervals during thewincling operation for patconnecting to the valve housing and being biassed to its closed position in engagement with the valve seating, and an end portion of the plunger protruding'from the valve housing toward the other valve housing and constitutingthe actuating member for engagement by the shuttle, whereby the initial engagement of said protruding end of the plunger by the shuttle partially opens the valve to deliver compressed air to the enclosed space between the telescoped valve block and shuttle end, whereupon the pressure of the compressed air delivered into the enclosed space acts on said protruding end of the plunger to open the valve fully.

'12. A pneumatic traverse device as claimed in claim 1 in which the shuttle comprises a double-acting cylinder member whose two ends comprise a pair of oppositely'facing aligned cylinders whose outer ends are open, which cylinders cooperate respectively with a pair of pistons aligned with the track and forming parts of the respective valve housings, each piston entering the respective shuttle cylinder with clearance between them at the end of a reciprocation stroke of the shuttle in a corresponding direction, and in which the actuating member of each control valve protrudes through the outer end face of the respective piston for engagement by the inner end face of the associated cylinder of the shuttle.

13. A pneumatic traverse device as claimed in claim 12 in which the track comprises a pair of rigid parallel guide rails on which the shuttle is slidably mounted, the shuttle and the fixed pistons lying between the guide rails.

14. A pneumatic traverse device as claimed in claim 12 in which the track comprises a pair of spaced parallel elongated channel-section guides whose channels face toward one another and together define an elongated guide passage of a cross-section corresponding to the external cross-sectional profile of the shuttle, the shuttle being slidable in the opposed channels of the two guides.

Claims

1. A high-speed pneumatic traverse device for leading yarn on to a rotary take-up spool of a yarn-winding machine by reciprocating the yarn transversely across the face of the spool, which comprises a linear track extending across the face of the take-up spool, a linearly reciprocable shuttle slidably mounted on the track for reciprocating movement therealong, a thread guide carried by the shuttle, means for applying compressed air alternately to opposite ends of the shuttle to propel the shuttle pneumatically along the track in successively-reversed reciprOcation strokes, which means comprises a pair of valve housings respectively mounted at opposite ends of the track, means for connecting both valve housings to a supply of compressed air, a pneumatic control valve in each valve housing, each control valve being biassed to a closed position and having an actuating member positioned to be actuated by the moving shuttle approaching the respective valve housing towards the end of a reciprocating stroke, the actuating member when so actuated opening the control valve to release a blast of compressed air which reverses the direction of motion of the shuttle and propels the shuttle along the track in its next-succeeding reciprocation stroke, and in which each valve housing is mounted for movement along the length of the track during the operation of the traverse device, and which includes a stroke-adjusting mechanism coupled to both valve housings and operable to move both valve housings progressively toward one another along the track at a controlled rated during the reciprocating motion of the shuttle so as to reduce the stroke length of the shuttle progressively during the operation of the winding machine.

2. A pneumatic traverse device as claimed in claim 1 in which the stroke-adjusting mechanism comprises a control member and a pair of driving mechanisms respectively coupled to the valve housings whereby movement of said control member in a given direction causes the two valve housings to be moved toward one another along the track.

3. A pneumatic traverse device as claimed in claim 2 including means for moving said control member automatically in response to the increase in radius of a package of yarn being wound on the take-up spool, whereby the two valve housings are moved toward one another proportionately to the increase in radius to form a package with tapering ends.

4. A pneumatic traverse device as claimed in claim 3 in which the track is mounted on a carrier pivotally mounted for movement toward and away from the take-up spool, and which includes a roller carried by the carrier for engagement with the external surface of the package of yarn being wound on the take-up spool, whereby the carrier is moved angularly relatively to the take-up spool in relation upon the increase in radius of the package, the carrier constituting said control member.

5. A pneumatic traverse device as claimed in claim 4 in which each said driving mechanism comprises a cam, and a cam follower coupled to the associated valve housing.

6. A pneumatic traverse device as claimed in claim 5 in which said cams comprise a pair of edge cams, each attached to a support for the take-up spool, and in which each said driving mechanism also includes a follower roller carried by the associated valve housing, and an adjustably mounted backing member, each edge cam being interposed between the associated follower roller and backing member and camming the valve housing away from the backing member and toward the other valve housing as the carrier is moved angularly away from the take-up spool.

7. A pneumatic traverse device as claimed in claim 6 in which the two edge cams are both slidable on the support for the take-up spool in a direction parallel to the length of the track, and which includes pattern-breaking means for rapidly moving one of the adjustably-mounted backing members through a short distance in a direction parallel to the length of the track to effect a rapid shifting of the associated edge cam and valve housing for pattern-breaking purposes.

8. A pneumatic traverse device as claimed in claim 1 including pattern-breaking means for rapidly shifting the position of each of the valve housings along the track at intervals during the winding operation for pattern-breaking purposes, said pattern-breaking means being arranged to override the actuation of the stroke-adjusting mechanism.

9. A pneumatic traverse device as claimed in claim 8 in which said pattern-breaking means comprises a motor-driven rotary cam mechanism coupled to both of said valve housings.

10. A pneumatic traverse device as claimed in claim 1 in which each valve housing and the associated end of the shuttle are constructed and arranged to telescope one within the other as a free-fitting piston-and-cylinder mechanism, and to enclose a space between them when so telescoped, the control valve when opened delivering compressed air into said enclosed space to act on the end of the shuttle.

11. A pneumatic traverse device as claimed in claim 10 in which each control valve is a poppet valve having a valve seating and a cooperating movable valve plunger aligned with the track, the plunger being formed with opposed piston faces respectively subject to oppositely directed differentially acting nearly balanced pressure thrusts by the compressed air supply connecting to the valve housing and being biassed to its closed position in engagement with the valve seating, and an end portion of the plunger protruding from the valve housing toward the other valve housing and constituting the actuating member for engagement by the shuttle, whereby the initial engagement of said protruding end of the plunger by the shuttle partially opens the valve to deliver compressed air to the enclosed space between the telescoped valve block and shuttle end, whereupon the pressure of the compressed air delivered into the enclosed space acts on said protruding end of the plunger to open the valve fully.

12. A pneumatic traverse device as claimed in claim 1 in which the shuttle comprises a double-acting cylinder member whose two ends comprise a pair of oppositely facing aligned cylinders whose outer ends are open, which cylinders cooperate respectively with a pair of pistons aligned with the track and forming parts of the respective valve housings, each piston entering the respective shuttle cylinder with clearance between them at the end of a reciprocation stroke of the shuttle in a corresponding direction, and in which the actuating member of each control valve protrudes through the outer end face of the respective piston for engagement by the inner end face of the associated cylinder of the shuttle.