Yarn monitor for two-yarn cabling or twisting machine

In a textile machine two primary yarns are fed under relatively low longitudinal tension from respective yarn supplies to a combining location at which they are combined into a single yarn. The combined yarns are fed from this location under relatively high longitudinal tension to a takeup station where they are wound up on a spool. The tension in the combined yarns is continuously monitored between the combining location and the takeup station and an output is generated when this tension drops from the high tension below a predetermined level at least equal to the relatively low tensions in the individual yarns. This occurs when one of the yarns breaks. The yarn feeds are interrupted when the output is generated to prevent forming an inadequately plied yarn.

FIELD OF THE INVENTION 
The present invention relates to a two-yarn twisting or cabling machine. 
More particularly this invention relates to a monitor for detecting yarn 
breakage in such a machine. 
BACKGROUND OF THE INVENTION 
Two-ply yarn twisting and cabling machines are described in commonly owned 
U.S. Pat. Nos. 4,163,357 and 4,180,967. These machines allow two separate 
primary yarns to be wound into a single two-ply yarn. One or both of the 
yarns, in addition, may itself be twisted. Such an arrangement therefore 
allows a two-ply yarn to be made with two yarns wound together in, for 
example, a S-twist, with the yarns themselves being twisted in a Z-twist. 
A particular problem with such device is yarn or thread breakage. Unlike a 
normal single-ply twisting machine with such an apparatus if one of the 
yarns breaks, the device will still continue to wind up the other yarn. In 
fact it is possible in such systems for one of the supplies to become 
depleted or one of the yarns to break and for this problem to go 
undetected so that a spool or yarn is supplied to a user, with the yarn 
being single-ply yarn instead of the desired double ply. The results of 
such an accident can be extremely grave in the production of high-quality 
textiles. 
It has been suggested to provide monitoring equipment for the individual 
yarns. This is relatively expensive due to the fact that two yarns at 
least are combiined in each cabling or twisting station of such a machine, 
which normally includes a plurality of such cabling or twisting stations. 
It is almost impossible to monitor the condition of yarn being twisted by 
such a machine, as it normally passes directly from its supply to the 
center of the twister spindle, and then forms a balloon whence it is fed 
to the combining location. Nowhere along this path is a convenient place 
the yarn can be passed through appropriate sensing equipment. No other 
solutions of this problem have met with any success. 
OBJECTS OF THE INVENTION 
It is therefore an object of the present invention to provide an improved 
yarn monitor for a two-yarn cabling or twisting machine. 
Another object is to provide such a monitor which can readily be used with 
the machines described in the above-cited patents. 
Yet another object is to provide such a monitor which can be added to such 
a machine at relatively low cost, yet which will surely and positively 
indicate when any of the yarns being combined by the machines has broken. 
Another object is to provide an improved method of operating a textile 
machine which automatically shuts down the machine when any of the yarns 
being combined by it breaks. 
SUMMARY OF THE INVENTION 
These objects are attained according to the instant invention by 
continuously monitoring the tension in the combined yarns between the 
location at which they are combined and the take-up station where they are 
normally wound up on a spool. An output is generated when the tension in 
these combined yarns drops from the normal relatively high tension in the 
combined yarns at this region below a predetermined level which is equal 
at least to the relatively low tension in the primary yarns downstream of 
the combining location. Such a tension drop normally results from breakage 
of one of the primary yarns or running-our of the respective supply. 
According to this invention the feeds of the yarns are interrupted when 
this output is generated. 
Thus the system according to the instant invention takes the novel approach 
of measuring the tension of the combined yarn, and shutting down the 
machine when this tension drops below a predetermined level. The tension 
in the combined yarn is substantially greater than the tension in any of 
the yarns making it up, and this tension drops whenever any of the 
respective yarns breaks. Unlike most similar systems which operate with a 
single yarn and which only respond when the tension drops to zero, the 
system according to the instant invention detects relative tension levels 
and generates its output, which in fact could be constituted by opening or 
closing a hydraulic, electric, or pneumatic circuit, when the tension 
drops from a relatively high level to another level still well above zero 
tension. The system can be set up relatively easily to function even in 
systems were quite a few yarns are combined. 
According to this invention the detecting means comprises a sensing element 
engaging the yarn in its path between the combining location and the 
takeup station and displaceable normally transversely in a direction 
transverse to this path. Means is provided such as a spring for urging the 
sensing element in one direction across the path, with the normal tension 
in the yarn inherently urging the element back in the opposite direction. 
This biasing force can be adjusted so that the sensing element, which 
according to this invention may be a two-arm lever having one arm carrying 
a roller engaging the combined yarn and another arm engaging a switch, 
will only move from a predetermined inner position to a predetermined 
outer position when the tension in the combined yarn drops below a 
predetermined level indicating that one of the filaments combined in the 
yarn is no longer adding its tension to that of the yarn. Such 
displacement from inner to outer position will either open or close the 
switch and shut down the yarn feeds. 
The system according to the instant invention therefore also serves as an 
excellent monitor for shutting down the cabling or twisting machine 
whenever one of the yarns runs out. 
According to the instant invention, therefore, means is provided for 
stopping the various yarn feeds whenever the sensing means generates its 
output. This means normally lifts the belt off the whorl of the twister 
while simultaneously engaging a breakshoe against the whorl and at the 
same time lifts the takeup spool off its drive roller. Such arresting 
means can advantageously be combined according to this invention with 
means for measuring the length of the combined yarns that passes a point 
along the path, this means also generating an output which can interrupt 
the feed of the yarns. Thus the system according to the instant invention 
will also shut down when a predetermined length of yarn has been wound up 
on the takeup spool, a much more accurate system than the prior-art which 
shuts the system down only when the takeup spool has attained a certain 
diameter.

SPECIFIC DESCRIPTION 
As shown in the drawing in FIGS. 1-6 the apparatus according to the 
invention basically comprises a frame 10 extending longitudinally in a 
direction perpendicular to the plane of the view in FIGS. 1 and 6 having a 
lower frame portion 12 and an intermediate portion 14. Two rows of 
twisters 16 are provided on this frame 10 at the lower frame portion 12 
and immediately above each of the twisters 16 is a respective takeup 
device 34. Above each of the takeup devices is a respective creel or 
second-yarn supply 64. FIGS. 1 and 6 show two side-by-side production 
units each having a respective twister 16, takeup device 34, and creel 64. 
A gangway is provided to each longitudinal side of the frame 10. 
Each twister 16 basically comprises a rotor 18 having a storage drum 60 
formed with a radially open aperture 19 and by a spindle 21 supported 
nonrotatably on the rotor 18 and carying a yarn package 20 of a first yarn 
54. Closely surrounding the yarn package 20 is an inner sleeve 22 fixed to 
the rotor 18 and coaxially surrounding this sleeve 22 is a 
balloon-limiting sleeve 24 forming an annular cylindrical space therewith. 
The sleeve 24 is fixed in the frame portion 12 and is therefore 
nonrotatable. Magnets coacting through the nonmagnetic sleeve 24 act on 
the sleeve 22 on the yarn package 20 and prevent it from rotating as the 
rotor 18 turns at high speed. A drive belt 26 operated by a motor 27 is 
pressed by idler rollers 28 against whorls 30 formed at the bottom 5 of 
the rotors 18. 
A transverse beam 32 above each pair of twisters 16 supports the respective 
takeup devices 34. Each such device has a takeup drum 36 mounted on a 
shaft 38 extending parallel to the longitudinal direction of the machine 
and rotated at a predetermined speed by the motor 27. A takeup spool 40 is 
frictionally engaged by the roller or drum 38 and is carried on an arm 42 
journaled at 46 on a post 44 extending upwardly from the intermediate 
portion 14 of the frame. A handle 48 connected to each of the arms 42 can 
be raised to lift the respective spool 40 off the respective continuously 
driven roller 38 for removal of a full spool. 
In accordance with the invention the yarn 54 is pulled upwardly off the 
package 20 and through a three-roller thread brake 56 carried on a support 
57 fixed to the inner sleeve 22 and thence through an eye 61 centered on 
the axis about which the rotor 18 rotates. Thence the filament 54 passes 
as shown in FIG. 1 directly to a deflecting roller 50 or through a yarn 
monitor 212 to the deflecting roller 50 which is rotatable about a 
horizontal arm 52. The yarn then passes through a guide eye 51 
reciprocated horizontally parallel to the axis of the respective spool 40 
in the manner described in U.S. Application No. 025,182, Mar. 29, 1979, 
now U.S. Pat. No. 4,231,531. 
A second yarn 58 is combined with the yarn 54 to form a cabled doubled yarn 
62. If this yarn 58 is not used the apparatus can be operated as a normal 
spinning machine with the yarn 54 being pulled from the pack 20, down to 
the spindle 21, thence out through the aperture 19 on the storage disc or 
drum 60, and thence up to the space between sleeves 24 and 22 to the eye 
61. Indeed two packages 20 can be mounted on the spindle 21 for doubling 
of the yarn during twisting. 
As shown in FIGS. 2-4, provided above each twister 16 is the yarn holder 64 
having a frame 68 and carried on a pivoting arrangement 66. The frame 68 
is of V-shaped and has a pair of arms 70 and 72 each carrying a respective 
mount 74 on its outer end. Each mount 74 as best shown in FIG. 2 comprises 
a base part 76 pivotal about a pin 77 on a respective arm and having a 
portion 78 on which is provided a mounting pin 80 for either of two yarn 
packages 82 and 84. The two pins or spindles 80 extend at an angle of 
120.degree. to each other. In addition each mount 74 allows for pivoting 
of the respective yarn package about the axis pin 77 relative to the 
respective arm. A locking device in the form of semispherical recess 66 
formed in the part 76 and a cylindrical recess 90 carrying a ball 88 
engaged in the recess under the force of a spring 92 is provided. The two 
arms 70 and 72 lie in an upright plane which includes the axis of the 
spindle 21 of the respective twister 16. 
A pair of struts 94 extend upwardly from the arms 70 and 72 and carry at 
their upper end a thread-guide arrangement 96 constituted by a stem 98 on 
the inner end of which is provided a typical thread eye or guide 100 and 
on the other end of which is provided another such thread guide or eye 102 
and a standard spring-loaded thread brake 104. The eye 100 lies in the 
intersection of the axis of the pins or spindles 80 in the plane whereas 
the eye 102 lies outside of this plane and indeed in a plane parallel to 
but offset in the longitudinal direction of the machine. 
At the upper end of post 44 the machine carries a longitudinal beam 106 on 
which are supported the inner ends of the parallelogrammatic link 66 best 
shown in FIGS. 2 and 3. A pair of struts 108 extending downwardly from the 
beam 106 make the entire upper assembly very rigid on the frame 10 of the 
machine. 
Each parallelogrammatic linkage comprises a pair of relatively long links 
110 and 112 connected together at their inner ends at respective pivots 
116 and 118 on a flange or inner link member 114 fixed to the beam 106. 
These pivots 116 and 118 are perpendicular to vertical planes horizontally 
perpendicular to the longitudinal direction of the machine. At their outer 
ends the two links 110 and 112 are pivoted to respective pivot pins 122 
and 124 on an outer arm 120 whose outer end is welded or flanged to the 
outer end of the one leg 70 of the V-shaped holder frame 64. The link 110 
is of U-section and has a pair of parallel flanges or legs 126 in which 
are provided the pivot pins 116 and 122 and which flank and receive most 
of the structure of parallelogrammatic linkage 66 and a web 128 
interconnecting these two flanges 126. 
A spring assembly 130 constituted by a pair of tension springs 132 received 
in respective shield tubes 134, has an end plate pivoted at 136 between 
the flanges 126 of the link 110 adjacent pivot pin 112, and at the other 
end has another plate secured at 138 above the pivot pin 118 between the 
pivot 116 and 118 to the flange 114. This spring arrangement 130 normally 
biases the parallelogrammatic linkage 66 into the operating position of 
FIG. 2 from the loading position of FIG. 3. A bumper strip 140 is provided 
on the face of the flange 114 to engage the inner surface of the web 128 
in the operating position so as to cushion return of the assembly to this 
operating position and to hold it sungly and vibrationless into place 
therein. 
In order to lock the parallelogrammatic linkage in the loading position a 
hooked pawl 142 is pivoted at 144 on the link 110 at the flanges 126 
thereof between the pivot pins 122 and 136. A torsion spring 146 has one 
leg 148 bearing on the web 128 and another leg 150 hooked over the pawl 
142 to urge the hook 152 thereof over the pivot pin 124 between the links 
112 and 120 in the working position. Thus once pulled down into this 
working position the spring-loaded pawl 142 will automatically snap over 
the pin 124 to hold the device in the working position. A lever 154 is 
fixed to PG,11 the pivot pin 144 allows the pawl 142 to be swung back and 
unhooked from the pin 124 so that the parallelogrammatic linkage 66 can 
automatically return to the operating position of FIG. 2. 
From the yarn guard 102 and thread brake 104 of FIG. 4 the second yarn 58 
is led down through a guide arrangement 156 to the machine frame. This 
guide arrangement 156 if formed by a tube 160 secured by clips 158 and 162 
to the machine frame and lying in the above-described filament plane. This 
guide tube 160 has an upstream end formed as an intake funnel 157 and a 
U-shaped part 159 that does not lie in the above-mentioned plane and that 
has another end opening upwardly in line with the axis of the respective 
twister 16. This tube 160 is divided at a fitting 161 into an upstream 
section 160a and a downstream section 160b. Fitting 161 comprises an outer 
sleeve 164 joining the two sections 160a and 160b and is formed with a 
passage 173 connected to an air-feed tube 175 connected at its other end 
to a valve 180. 
A pneumatic threader of the type described in commonly owned U.S. Pat. No. 
4,047,372, to which reference should be made for further specifics, can 
blow-thread a filament through this tube 160. In this case the fitting 161 
is not needed. 
Provided inside the sleeve 164 between the sections 160a and 160b is a 
nozzle insert 166 having a central throughgoing passage 169 opening at its 
upstream end at a flared portion 168 and having an outwardly open groove 
171 at the passage 173 and forming an annular chamber. Inclined bores 191 
communicate between the chamber formed by the groove 171 and the passage 
169 and are inclined inwardly and downwardly in the tube 160. 
The valve 180 has a valve housing 177 formed with a throughgoing passage 
185 connected at one side to the tube 175 and at the other side to a tube 
179 connected to a source of compressed air. A valve body 181 is 
displaceable in the housing 177 across the passage 185 and is formed with 
a bore 183 alignable with the passage 185. A spring 189 urges this valve 
body 181 into a position with the bores 183 and 185 misaligned. Depressing 
a knob 187 can align these bores and, therefore, feed compressed air from 
the line 179 to the line 175 and therethrough to the chamber 171. This 
compressed air will exit from the passages 191 and form above a level L at 
the mouths of these passages 191 a low-pressure zone. 
If the button 187 is depressed and a free end of a filament 58 is dropped 
into the funnel 157 the low pressure will suck this filament down along 
the tube 160. 
The other end of the tube 160 passes at 165 through the support beam 163 
underneath the respective whorl 30. The tube 160, however, opens into the 
lower end of the spindle shaft 21 to guide the filament thus fed 
pneumatically into the interior of the spindle 21. This spindle 21 is 
provided adjacent the radially opening hole 19 with a lateral deflector so 
that the filament thus pneumatically entrained will automatically be blown 
out of this hole 19. A downwardly tapering frustoconical deflecting collar 
193 is provided on the sleeve 24 so that the filament thus blown radially 
out of the drum 60 will be deflected upwardly to the location indicated at 
195 in FIGS. 1 and 6. In this position it is a relatively simple matter 
for the operator of the machine to grab the filament and further thread it 
in the machine. 
According to this invention the two filaments 54 and 58 are united at a 
roller 201 best seen in FIGS. 7-9. This roller 201 is fixed on a mount 208 
itself secured to a longitudinally extending square-section beam 209 of 
the textile machine according to this invention. The two filaments 54 and 
58 are combined at this roller 201. Since the yarn 58 is orbiting rapidly 
about the yarn 54 they will there be cabled or twisted together. 
The sensing means or apparatus 212 has a sensing element constituted as a 
roller 203 carried on a two-arm lever 205 pivoted at 207 on the mount 208. 
This lever 205 has one arm 206 carrying the roller 203 and another arm 210 
into which is screwed a screw 21 engaging a compression spring 213 
received in a cylindrical bored 214 in the mount 208. This spring 213 
urges the sensing element or roller 203 in a direction across the paths of 
the combined yarns 54, 58, the tension in these yarns 54 and 58 therefore 
urging the roller 203 in a direction opposite the biasing force of the 
spring 213. The end of the arm 210 is formed with a camming surface 215 
engageable with a roller 216 on an arm 217 pivoted at 218 on a switch 219. 
This switch 219 is connected to a pneumatic valve 220 having a feed line 
221 and two output lines 222 and 226. When the arm 217 of the switch 219 
is allowed to swing out, that is when it is no longer engaged by the 
surface 215, it closes a circuit and opens the valve 220 to supply 
compressed air from the line 221 to the lines 222 and 226. The line 222 is 
connected to a respective cylinder 223 that operates an arm 224 having an 
end 225 constituted as a roller and engaging the respective takeup roll 
40. When pressurized the cylinder 223 therefore can lift the respective 
spool 40 off its drive roller 36 and, therefore, stop its rotation. The 
line 226 is connected to a combined lift-off device and brake 227 which at 
the same time disengages the belt 26 from the respective whorl 30 and 
applies a brake to this whorl 30, thereby stopping the respective twister 
16. 
In addition provided downstream of the sensing roller 203 is a wheel or 
roller 204 connected to a counter 229 which can be set at zero, and can be 
set to generate an output signal identical to that of the switch 219 when 
a predetermined length of the combined yarns 54 and 58 has passed it. Thus 
when a predetermined amount of yarn has passed this wheel 204 it will 
generate an output that will, like the output of switch 219, shut down the 
respective twister and lift the respective takeup spool off its drive, 
thereby completely stopping the yarn feeds. 
The system according to the instant invention is set to operate when the 
tension in the combined yarn 54, 58 drops from a relatively high level to 
a lower level still well above zero tension. In normal situations where 
two yarns are being cabled together the total tension in the combined yarn 
will be approximately equal to the sum of the tensions of all of the 
respective yarns. In situations where the yarns are just being twisted 
together, however, the tension will not drop drastically when one of the 
yarns breaks, but instead will merely drop, for example, by 30% when one 
of two yarns breaks. Nonetheless the system is set up so that when any 
such tension decrease occurs the roller 203 will move to the right in FIG. 
7, pivoting clockwise, and will disengage the switch roller 216 so as to 
close the switch 219 and shut down the various yarn feeds. The same thing 
will happen when sufficient yarn has been detected by the counter wheel 
204. The system according to the instant invention therefore is capable of 
detecting when any of the filaments being wound on the device breaks, even 
though it operates at a location where all of the yarns are present.