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Патент USA US3093293

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June 11, 1963
Filed Oct. 51. 1960
2 Sheets-Sheet 1
June 11, 1963
Filed Oct. 51. 1960
2 Sheets-Sheet 2
F/ G. 3.
/44 ,4/1/ #52245 W000
United States Patent ?ice
Alan Hezzlewood, Usk, England, assignor to British
Nylon Spinners Limited, Pontypool, England
Filed Oct. 31, 1960, Ser. No. 66,133
Claims priority, application Great Britain Nov. 12, 1959
w Patented June 11, 1963
contact therewith and wherein an air ?ow is created hav
ing at least a component of motion in the direction of
travel of the thread as it leaves the said roller and acting
on the thread at, or closely adjacent to, the point whence
the thread departs from the said roller and having at most
no substantial component of motion in that direction
which is inwardly radial of the roller ‘at the point whence
the-thread departs from the said roller.
The invention also comprises apparatus for reducing or
The present invention concerns improvements in or 10 eliminating the tension of a running thread, comprising
relating to the controlling of tension in running threads,
a driven roller, around a portion of whose periphery the
and has particular reference to the elimination, or vir
thread is passed, and means acting in combination with
tual elimination, of tension therein.
the roller for creating an air flow having at least a com
The effect of ?uctuations in the tension of a running
ponent of motion in the derection of travel of the thread
thread used as a supply in textile operations, such as 15 at, or closely adjacent to, the point whence the thread
warping, weaving and knitting, leads to irregularities in
departs from the said roller and having at most no sub
the product made in that operation, which irregularities
stantial component of motion in that direction which
in the case of fabrics are often sut‘?ciently obvious to
is inwardly radial of the roller at the point whence the
lead to their rejection. Tensioning devices of the simpler
thread departs from the said roller.
varieties such as are used in by far the greater propor 20
In one convenient embodiment of the invention, the
6 Claims. (Cl. 226—7)
tion of all textile operations, are useful in imposing a
moderately uniform output tension therefrom; but, unless
the more complicated and expensive varieties of device,
having provision for compensating for variations in‘ input
roller itself serves to create the air ?ow. Due to its rota
tion, and to the frictional characteristics of its surface,
the roller will carry around with it a body of air. It is
possible, by positioning guide vanes, or shields, around
tension, are utilized, the fact is that variations in the 25 that part of the periphery of the roller with which the
input tension of the thread will be exaggerated by the
thread makes contact and extending away from the roller
tensioning device, and hence will cause defects in, say,
to form a diverging space around the thread as it leaves
fabrics which may lead ‘to their rejection.
the roller, to channel the thus-created air-?ow into the
Variations in input tension, i.e. the tension‘ in a thread
‘general direction of travel of the thread as it leaves the
immediately prior to its arrival at a textile instrumentality, 30 roller.
if no tensioning device is utilized, or at a tensioning de
Alternatively, in another embodiment of the invention,
vice ?tted to act on the thread prior to its arrival at a
the air ?ow may be created by means extraneous to the
textile instrumentality, such as knitting machine needle,
roller, as by a simple jet connected to a supply of com
are normally present due to variations in tension resulting
pressed air, or by an air turbine operating within a casing,
from the action of take-01f from the thread supply pack 35 part of which is cut away and shaped so as to channel the
age and from variations in the tension of winding-on.
air ?ow in a direction that enables it to assist in helping
Whereas steps to try and eliminate such variations are
the thread to quit the roller, as must occur also with the
always being taken, the critical nature of tension faults in
construction embodying the compressed air jet.
some fabrics, such as circular-knit ?ne nylon stockings,
The two vital components of the invention, namely the
makes it very di?icult to eliminate the variations to below
rapidly-rotating roller and the air ?ow, act together in
the signi?cant level especially when take-off from the
such a way that the output tension in the yarn is reduced
supply package is over one end thereof, as is the normal
compared with the input tension and reduced to a steady
procedure on a circular knitting machine. Hence, the
in?nitesimally small quantity whatever the variations in
problem is a very real one, particularly in the case of
tension within the ordinary range, and the thread
the critical processes alluded to above; and efforts to solve 45 is assisted to depart from the periphery of the roller at
it with known tensioning devices have not been altogether
the appropriate point. a
successful, even when devices have been used which aim
The effect of the peripheral speed of the roller being
to compensate for variations in input tension.
greater than (say, of the order of 50% greater) the linear
We have now approached the problem from a diner
speed of the thread is to apply negative friction to the
ent aspect altogether; and according to the invention we 50 thread in a direction contrary to its travel. Thus, com~
provide speci?c means for eliminating, or virtually elimi
pared with the cases when the roller’s peripheral speed
nating, all tension in a running thread, and then either
is zero or any speed lower than that of the thread, or
utilizing the ten'sionless thread directly as in a laboratory
when it is equal to thatof the thread, in which cases,
testing process or in a textile process, such as knitting,
respectively, the roller serves to multiply or to add to
or passing it through a tensioning device before utilizing 55 the input tension in the thread, the roller in the process
it in a testing or textile process in those cases where a
of the invention serves to subtract ‘from the input tension.
positive feed tension is required. The fact that the thread
The air ?ow must be in such a direction relative to the
is virtually tensionless means that a tensioning device of
the additive type, such as the double-disc tensioner, can
direction of travel of the thread as it leaves the roller in
60 conditions of normal operation, that the air will assist in
be used in this latter instance without fear of the output
the departure of the thread from the periphery of the
tension being caused to ?uctuate because of variations in
roller. Thus it should always act in a direction adapted
the input tension. Furthermore, the passing of the ten
to prevent the thread from becoming wrapped around
sionless thread through guides will not lead to the tension
the periphery of the roller with a greater angle than the
multiplying effects that are normally found and such do
normal one; and such correct action will occur even‘ when
not therefore have to be so closely guarded against as 65 the air ?ow, although slightly diverging, is in the same
general direction as that of the thread leaving the roller.
The invention comprises a process for reducing or
The combination of apparatus in the process of the
eliminating the tension of a running thread wherein the
invention acts as a servwmechanism, in that variations in
thread is passed in contact with a portion of the periphery
input tension will automatically be compensated for, and
of a roller that is rotatably driven at a peripheral speed 70 a uniform zero or in?nitesimally small output tension be
greater than the linear speed of travel of the thread in
maintained, by corresponding variations in the angle
through which the thread wraps in contact with the pe
riphery of the roller. This is so, because an increase in
input tension will bring about an increase in the wrap
angle, such that the negative frictional effect of the roller
form a free-loop, extending either upwardly, downwardly
‘is increased by an amount su?icient to reduce the in
creased tension to around zero 'at the point of departure
of the thread from the'roller.
The invention will now be described with reference to
or sideways, the advantage of which is that the correct
ness or otherwise of the settings of the roller speed and
of the air flow will be immediately apparent to an op
A critical function of the air flow arrangements in
those processes in which the utilization of thread is only
intermittent, such as a circular-knitting process, is to
create the necessary conditions that will prevent the
FIGURE 1 is a side elevation of apparatus according 10 thread from being continuously forwarded by the device
after utilization thereof has ceased. ‘In the embodiments
to the aforesaid convenient embodiment;
described, this function will be performed satisfactorily,
FIGURE 2 is a‘ section through II'-—II of FIGURE 1;
in the case of the embodiment described with reference
FIGURE 3 is a side elevation of apparatus according
to 'FIGURES 1 and 2 by reason of the back pressure
to another embodiment; and
FIGURE 4 is a section through IV-IV of‘FIGURE 3. 15 caused along the thread as it builds-up in folds between
the slightly diverging vanes, immediately after utiliza
The convenient embodiment illustrated in FIGURES 1
tion has ceased, leading to the contact between the thread
and 2 will ?rst be described. Yam 1, such as nylon 15
and the roller becoming so light as to allow 100% slip
denier mono?larnent, from a source not shown, such as a
the accompanying drawings, in which:
page to occur, and in the case of the embodiment de
supply package, is led to‘the tension eliminator of the
embodiment, shown generally at 3, the means for im 20 scribed with reference to FIGURES 3 and 4 by reason of
the air ?ow causing a slight increase in the size of the loop
parting linear movement to the yarn also not being shown
of thread that has just left the roller, this having the
but consisting, say, of‘ some'feed mechanism acting on
same eetfct as in the other case on the contact between
the yarn after its travel through the tension eliminator.
the thread and the roller. It is, of course, possible to
The yarn is passed via guide pins 4, with a wrapping
arc of some 120°, around aluminium roller 5 mounted 25 have separate interlock means that will automatically
on shaft‘ 6 which is driven by electric motor 7 with a
remove the thread from contact with the roller on the
peripheral speed 60% higher than the linear speed of the
ceasing of utilization and that will automatically direct
yarn in contact with it. The yarn in the tension elimi
nator is enclosed between a black “Perspex” (registered
it back in contact with the roller on the re-starting of
plate or window 11, hinged at 13. Motor 7 is housed
within 'a casing ‘15, and is supplied with power through
It is, however, sometimes essential to have such means,
as when the peripheral surface of the roller has a very
cable 17. Vane, or shield,‘19 is shaped and positioned
close to and surrounding roller 5 for the portion of the
high coefficient of friction with the thread, for example
when it is composed of rubber.
utilization, but such means are not to be preferred ow
trademark) back plate 9 and a plain “Perspex” front 30 ing to their added complication to the device as a whole.
The nature of the peripheral surface of the roller is,
periphery with which the yarn is ‘in contact, and then to 35
in fact, a matter of prime importance in the operation
extend to the yarn-departure end of the tension elimi
of the invention, and it must be selected with a view to
nator. Vane, or shield 21 extends from adjacent the
allowing the device to cope with the range of tension
roller 5 to the yarn-departure end of the tension elimi
variations that can be expected to be present in the thread
nator, and together with vane 19 forms a space, the top
supplied to it. For example, a rubber surface is capable
and bottom boundaries of which diverge at an angle of
of eliminating tension in a supply thread having tension
171/2“, within which the yarn travels from the roller
variations in it of a size, in grams, up to the breaking
out of the‘ tension eliminator. At its closest, vane 19 is
load of the yarn, which is, of course, the maximum
only 1,46 inch away from roller 5, this forming a partial
annular space; and the rotation of the roller is such as to 45 capability required. Such maximum capability is not
often required, however, owing to the‘generally lower
cause‘air from this space to be expelled as an air ?ow
order of tension variations that are met with in practice;
23, shown by the arrows, travelling in the same general
and consequently, metal surfaces, whether smooth or
direction as the yarn away from the roller. The tension
matt, are normally quite satisfactory, and do not have
in the yarn after it has left the roller will be maintained
at substantially zero.
50 the complication that rubber surfaces introduce when
In the embodiment illustrated in FIGURES 3 and 4,
yarn 1 is led into the tension eliminator 3 through guide
25. It is then passed via chrome wire guide 27, around
a portion of the periphery of roller 5 which is mounted
utilization of thread is only intermittent.
One particularly advantageous use of the invention is
in connection with the knitting of the panel yarns of a
circular-knit stocking, where minor variations in take
on shaft 6 and driven by electric motor 7 at a peripheral 55 off tension from a double-taper bobbin of low-twist
nylon mono?lament yarn, which ordinarily may result in
speed some 25% greater than the linear speed of the
tension rings visible in the knitted stocking, are eliminated
yarn, which may he, say, 500 feet per minute. Impeller,
if apparatus according to the invention is ?tted on the
or air turbine, 29, is driven by means of a belt'31 and
knitting machine in a position allowing the yarn to be
pulley 33 directly from the‘shaft 6. The impeller, or
turbine, 29 has curved blades 35; and it has a casing 37 60 drawn through it soon after leaving the bobbin.
What I claim is:
so shaped and positioned around the turbine that air is
1. A process for reducing the tension of a running
forced out in air flow 23, shown by the arrows, travelling
thread which comprises? contacting said running thread
in a direction tending to prevent further wrapping of the
with an arcuate portion only of the periphery of a roller;
yarn around roller 5. Yarn 1 is led out of the tension
eliminator around guide 39; and, as in the case of the 65 rotating said roller at a peripheral speed greater than
the maximum linear speed of the thread in contact there
other embodiment, the yarn‘ in the tension eliminator is
with; and directing a steady flow of air tangential to
protected in a space of about 1%: inch depth, between a
said periphery at the point thereon at which the thread
black “Perspex” back plate, 9, and a plain “Perspex”
departs from said roller and in the direction of departure
window 11, hinged at 13. Electric motor 7 is housed
within'a casing 15, and is supplied with power by cable 70 of said thread, the directing of said flow of air includ
ing the step of at least partially enclosing said portion
17. Again, the tension in the yarn between roller 5 and
of said roller' to form a partial annular space containing
the guide 39 is substantially zero.
said running thread whereby rotation of said roller creates
It is sometimes desirable, according to'any of the em
said ‘?ow of air due to friction between air in said partial
bodiments of the invention that the thread on departure
from the rapidly-rotating roller, should be allowed to 75 annular space and the surface of said roller.
2. Apparatus for reducing the tension of a run
ning thread comprising: a driven roller adapted to re
ceive the running thread around an arcuate portion of
the periphery; and means acting in combination with
said roller for creating a steady ?ow of air whose di
6. Apparatus according to claim 2 wherein the pe
ripheral surface of the roller is of rubber.
References Cited in the ?le of this patent
rection of flow is tangential to said periphery at the
point thereon at which the thread departs from said
roller and is in the direction of departure of said thread,
said means including a curved vane positioned close to
and partially surrounding said roller whereby a partial 10 2,537,000
annular space is formed around said roller and whereby
friction between the surface of said roller and air in said
partial annular space creates said ?ow of air.
3. Apparatus according to claim 2 wherein slightly
diverging vanes positioned between front and lback plates 15
enclose the thread-line from the point of departure of
the thread from the roller.
4. Apparatus according to claim 2 wherein the pe~
ripheral surface of the roller is of metal.
5. Apparatus according to ‘claim 4 wherein the metal 20
surface is a smooth surface.
Sti'bbe et a1. __________ _.. Jan. 2, 1951
Schoonenberger et al. ____ Dec. 18, 1951
Waugh ______________ __ Oct. 27, 1959
Newton _____________ __ Sept. 13, ‘1960
Meinshausen _________ __ Oct. 11, 1960
Knebusch et a1. ______ __ Sept. 26,
Lamesch ____________ __ Sept. 9,
McDermott ___________ _. Aug. 17,
Sweden _____________ .._ Mar. 23,
‘53 1,351
Great Britain __________ __ Jan. 2,
France ______________ __ July 15,
Great Britain _________ __ July 5,
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