Automatic threading device for filament winding machines

A thread monitor moving along a bank of upright spindles surrounded by vertically reciprocable track rings engaged by travelers, designed to facilitate the winding of yarns, rovings or other filaments on cops carried by the spindles, includes a suction tube picking up loose ends of ruptured filaments for tying them to fresh oncoming threads. A filament-threading device moving with the thread monitor comprises a gripper with a closable hook, displaceable on the level of the track ring, and a deflector in the form of a transverse roller eccentrically rotatable about a horizontal axis skew to the spindle axis. A loose thread end held under tension by the suction tube extends from the cop around the deflector in a first pass, lying high enough above an upper ring flange to give clearance to the traveler carried by this flange, and then via the closed gripper hook to the suction tube; upon an advance of the gripper from a retracted position to a working position alongside the ring, a second pass of the thread end comes to lie approximately tangentially to the ring flange at a small inclination to its plane whereby the traveler, driven by a circulating air flow originating at a nozzle on the deflector support, embraces this second pass and re-engages the ruptured thread. A rotation of the deflector about its axis then elevates the pass so engaged and dislodges the loose thread end from the deflector while the opening of the gripper hook releases this thread end to further aspiration by the suction tube preparatorily to tying.

FIELD OF THE INVENTION 
Our present invention relates to a thread-winding machine of the type used 
for the spinning or twisting of filaments such as rovings or yarns, each 
filament being wound on a bobbin core or cop placed on a rotating, usually 
upright spindle. 
BACKGROUND OF THE INVENTION 
Machines of this type generally comprise a large number of winding stations 
formed by parallel spindles rising from a common bed, each spindle being 
spacedly surrounded by a coaxial track ring carrying a traveler through 
which the filament to be wound upon its cop is threaded. The track rings 
are mounted on a common shelf, or ring bank, which is vertically 
reciprocable with reference to the spindle bed in order to distribute the 
turns of the filament as uniformly as possible along the cop surface. 
In the operation of such machines, the feeding of the filaments to the 
several spindles is frequently interrupted by a rupture which may be due 
to an actual breaking of the thread or to the fact that the thread of an 
associated supply spool has run out. Since a loose thread end remaining on 
an incompletely wound and still rotating cop may become entangled with the 
filaments of adjoining winding stations, it is customary to provide the 
machines with automatic thread monitors on carriages traveling along the 
bank of spindles in order to detect the presence of a rupture. These 
conventional thread monitors automatically arrest any spindle found to 
have a loose thread end, that end being then picked up by a suction tube 
and led to a tying mechanism which automatically connects it with a fresh 
oncoming thread. Before the winding station involved can resume its normal 
operation, however, it is necessary to reintroduce the previously ruptured 
thread into the associated traveler. 
Systems are already known which automatically carry out this rethreading of 
a traveler. In these systems, the loose filament end drawn away from the 
cop by the suction tube is gripped at an intermediate point and bent into 
two angularly adjoining passes, one of them coming to lie on a flange of 
the track ring engaged by the traveler while the other pass approaches the 
ring more or less tangentially so as to cross the path of the traveler 
driven around the flange by a circulating air stream. It may happen, 
however, that the traveler finds itself trapped in a dead zone between the 
two passes, encompassing perhaps a segment of 50.degree. to 80.degree. of 
the ring periphery, being thus prevented by the first pass from reaching 
its point of engagement with the second pass. A temporary withdrawal of 
the thread from the track ring then becomes necessary in order to let the 
traveler move on whereupon the rethreading operation can be tried anew. 
OBJECT OF THE INVENTION 
The object of our present invention, therefore, is to provide improved 
means on a thread monitor for reinserting a loose filament end into a 
traveler with avoidance of the aforestated problem. 
SUMMARY OF THE INVENTION 
A thread monitor embodying our invention comprises, in its basically 
conventional part, pickup means such as the aforementioned suction tube 
for seizing a loose filament end as well as gripper means for engagement 
with this loose end at a point between the pickup means and the cop from 
which that end is drawn. 
According to the present improvement, we further provide deflector means 
extending generally skew to the spindle axis at a location offset from the 
level of the track ring for intercepting a portion of the loose filament 
end lying between the cop and the gripper means, thereby dividing that 
portion into a first and a second pass as described above but with the 
difference that the first pass is held at a distance from the 
traveler-carrying ring flange sufficient to give clearance to the 
traveler. An actuating mechanism advances the previously retracted gripper 
means substantially at the level of the track ring to position the second 
pass approximately tangentially adjacent the aforementioned flange at a 
small angle of relative inclination which enables the traveler, driven by 
fluid-circulation means, to embrace this second pass whereupon the engaged 
thread portion is disengaged from both the deflector means and the gripper 
means by the operation of suitable release means. 
According to a more particular feature of our invention, the deflector 
means comprises a roller with a peripheral recess accommodating the 
engaged filament portion. The roller has an eccentric shaft rotatably held 
in a support which may be immovably mounted on a thread-monitor carriage, 
at a fixed distance from the track ring. The release means comprises a 
linkage connected with that roller (e.g. by way of its shaft) for rotating 
same through an angle of, say, 90.degree. to 120.degree. from a first 
position, in which its peripheral recess is averted from the spindle, into 
a second position in which that recess faces the spindle. In this latter 
position the terminal thread portion, still under tension from the pickup 
means, is pulled off the deflecting roller by way of the traveler in which 
it is now inserted. The release from the gripper, occurring substantially 
at the same time, may be effected by the withdrawal of a latch serving for 
the closure of a thread-engaging hook.

SPECIFIC DESCRIPTION 
In the drawing we have shown part of a winding station of a basically 
conventional textile machine for the spinning or twisting of yarn. The 
station comprises an upright spindle 10 rotatable about its axis O by a 
nonillustrated motor. A cop 11 fitted on spindle 10 carries an as yet 
incomplete yarn package 12 and is spacedly surrounded by a track ring 13 
on a mounting 17 which is vertically reciprocable with reference to 
spindle 10. Ring 13 has an upper flange 13' straddled with clearance by 
the lower ends of a generally C-shaped traveler 22. 
A conventional thread monitor, comprising a nonillustrated carriage riding 
a track rigid with the ring mounting 17, scans the bank of spindles 10 to 
detect any yarn rupture. This thread monitor includes a suction tube 26, 
lying well above the level of ring 13, which aspirates the loose end of a 
thread 19 forming part of yarn package 12; this loose end is drawn to a 
yarn-tying mechanism (not shown) which connects it with a fresh oncoming 
thread in a manner known per se and not relevant to the present invention. 
The carriage of the thread monitor also supports an elongate gripper 15, 
which is limitedly swingable and longitudinally displaceable in a 
horizontal plane at the level of ring 13, as well as an arm 14 disposed at 
a somewhat higher level and maintained at a fixed distance from ring 
mounting 17 and spindle axis O. Gripper 15 terminates in a hook 15a which 
is closable by a latch 16 longitudinally slidable therein. The movements 
of gripper 15 and latch 16 are controlled by a mechanism schematically 
represented by a set of links 31, 32 and 33. 
Arm 14 is traversed by an eccentric shaft 24 of a deflecting roller 20, 
this shaft defining a horizontal pivotal axis skew to the spindle axis O. 
Roller 20 is formed with a peripheral recess 21 bounded at its outer end 
by a transverse wall 23; a pin 25 projects radially from the roller in the 
vicinity of this wall 23 and in a direction away from shaft 24. Roller 20 
has two distinct positions, namely a working position shown in FIGS. 1-4 
and a disengagement position shown in FIGS. 5 and 6. In the working 
position, recess 21 is averted from spindle axis O and faces directly away 
from ring 13; in its disengagement position, offset by somewhat more than 
90.degree. from the working position, the recess is turned toward spindle 
10 and ring 13. The rotation of the roller between these two positions is 
effected by a mechanism partly represented by a pair of links 27, 29 
articulated to each other at 28. 
Arm 14 terminates in a nozzle 30, illustrated in FIG. 3, which is trained 
upon the annular gap existing between ring 13 and cop 11. Nozzle 30 
communicates with a source of air under pressure to generate a circulating 
air flow within that gap, rotating in a clockwise direction as viewed in 
FIGS. 1, 3 and 5, upon the opening of a nonillustrated valve. The 
generation of this air flow and the operations of gripper 15 and deflector 
20 are controlled timed relationship, as described hereinafter, by a 
nonillustrated programmer on the thread-monitor carriage. 
In retracted starting positions shown in FIGS. 1 and 2, in which the 
terminal thread portion 19 has been picked up by suction tube 26, hook 15a 
of gripper 15 has already engaged that thread portion which is positively 
retained in the hook by latch 16. The thread is pulled away from cop 11 
across roller 20, coming to lie within its recess 21 before passing into 
tube 26 by way of hook 15a. Gripper 15, normally parallel to support arm 
14, is inclined at this instant toward arm 14 so that its axis is 
approximately tangent to yarn package 12. The rotation of spindle 10, 
normally clockwise as viewed in FIGS. 1, 3 and 5, has been briefly 
reversed by the thread monitor for paying out a sufficient length of 
thread 19 to enable its entry into tube 26; the spindle is stationary at 
the stage here considered. 
It will be noted that roller 20 is sufficiently elevated above the level of 
ring 13 to prevent any contact between thread 19 and flange 13', the 
spacing of the thread from the flange being wide enough to let the 
traveler 22 pass freely underneath. This spacing does not change as the 
gripper 15 is swung clockwise (arrow A, FIG. 1) into the position of FIGS. 
3 and 4 in which the thread bends around the end wall 23 of recess 21. 
Next, as indicated by an arrow B in FIG. 3, the gripper 15 now paralleling 
the arm 14 is longitudinally advanced into a position 15' shown in phantom 
lines in which the thread has two passes 19' and 19" including an acute 
angle with each other. Pass 19', extending from yarn package 12 to roller 
20, still lies high above flange 13' so as not to intercept the traveler 
22 if the latter happens to be in the position illustrated in solid lines 
in FIG. 3, i.e. between two vertical planes which contain the passes 19', 
19" and include an angle of about 50.degree. to 80.degree. with each 
other. The simultaneous emission of an air stream from nozzle 30, as 
indicated by an arrow C, drives the traveler from this or any other 
position on ring 13 into an engagement position 22' illustrated in phantom 
lines in FIGS. 3 and 4. In the latter position, the traveler embraces the 
pass 19" of the thread which is substantially tangent to ring 13 below 
flange 13' and is inclined at a small angle to the horizontal. If the 
traveler happens to be already in this engagement position 22' at the 
instant when hook 15a is advanced into its phantom-line position 15' 
alongside ring 13, thread portion 19" snaps directly into the traveler 
from below. 
Thereafter, with air stream C cut off and gripper 15 still in its advanced 
position shown in FIGS. 5 and 6, linkage 27-29 is actuated to rotate the 
roller 20 into its unloading position. With pin 25 insuring that the 
thread 19 does not remain looped around roller 20, the thread is 
disengaged from the roller and drawn further into tube 26 which still 
exerts suction. Finally, the retraction of latch 16 opens the hook 15a for 
a complete release of the thread. If desired, spindle 10 could also be 
rotated at this time in its normal (clockwise) direction to help tension 
the thread. 
During the operations just described, ring bank 17 and the 
thread-monitoring carriage with tube 26, gripper 14 and arm 15 may 
continuously reciprocate vertically so that the other winding stations 
with unbroken threads may function normally. 
Reference may be made to U.S. Pat. Nos. 3,128,590 and 3,486,319 for a 
description of yarn-tying devices to which our invention is applicable.