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Патент USA US2407100

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. Sept. 3, 1946.
21,407,100
E. L..l RICHARDSON y
DRAFTlNG 0F FIBERS”
Filed June 26, 1943
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Inventar
Ernest» L.Ri_char-=d§oh,
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Sept» 3, 1945A
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E. L. RICHARDSON. -
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2,407,100
DRAFTING» 0E FIBERs
Filed June 2e, 194s
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Inventor: .
Ernest L.. Richardson,
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2,407,100
Patented Sept. 3, V1946
UNITED STATES PATENT OFFICE
2,407,100
DRAFTING OF FIBERS
Ernest L. Richardson, Melrose, Mass., assignor to
General . Electric Company, a corporation of
New York
Applicauon June 26, 194s,l seria1No~`49a425
12 Claims.
1
,
This invention relates to the processing of
fibers to form yarns or threads; more particu
larly to means employed in the drafting of fibers;
and it has for an object the provision of a simple,
reliable, inexpensive, and improved means of this
character.
`
(Cl. lil-«70)
`
`
2
of the ñbers to eliminate or minimize these varia
tions in thickness, thereby to improve the quality
of the final product.
If all the fibers were of the same length, this
could be accomplished by passing the length of
material through two pairs of rollers, of which
the spacing ofthe rollers is only just greater than
,
In certain of the preparatory steps in the proc
essing of fibers to form ayarn or thread, a length
the liber length. With such an arrangement, the
of materials, such as a sliver or roving, contain
tail of each fiber would no sooner leave the con
ing an' array of fibers is subjected to a series
trol of the ñrst pair of rollers, i. e. the entry or
of drafting operations before being converted
“retaining” rollers, than it would corne under
into the final yarn or thread form.
the influence of the second pair, i. e. the “draw
ing” rollers. The changeover would be accom
plished by a sudden acceleration on the part of
the fiber from the speed of the first pair of rollers
When the material is made up into sliver form
for the ñrst time, whether it be by means of card
ing or in any other way, it falls very far short
of the ideal so far as regularity and uniformity ‘
to the speed of the second pair. It would only
of density are concerned. The constituent fibers
are by no means perfectly mixed, and both long
through successive pairs of drafting rollers which
be free from positive control by one or the other
pair of rollers fora brief instant.
However, in practice the ideal of fibers of equal
length is usually not realized. The spacing of the
successive pairs of rollers cannot be less than the
length of the longest fibers because otherwise they
would be held simultaneously by both pairs of
are driven at progressively higher speeds to cause
the fibers to slide over one another and thereby
decrease the overlap between each fiber and its
neighbors. If a sliver or roving is first passed
The shorter fibers, constituting the great bulk of
the material under treatment, are drafted under
conditions that are very unsatisfactory. When
and short wave variations in thickness are con
siderable.-
,
Drafting is usually accomplished by passing a
length of material containing an array'of fibers
rollers and would be either broken or not drafted.
within the drafting field between the two pairs
through the nip of one pair of rotating rollers and
of rollers, they are under no direct control by
then through the nip of a second pair of rollers
which is rotating live> times as fast as the first 30 either pair of rollers and depend for their sup
-port and their movements entirely on the other
pair, the issuing sliver or roving must be ñve times
fibers with which they are in contact.
as long and five times as thin. The draft in such
The retaining rollers retain their hold upon
case is five.
the long fibers until they are in position to be
In spite of the use of many devices and methods
taken by the drawing rollers. But with the short
intended to produce uniformity, the sliver from
fibers there is no such control. They are re
which the roving and finally the yarn or thread
leased by the retaining rollers when they still
is produced contains thick portions and thin por
have some distance, depending on their length,
tions. The occurrence of thick and thin places
to go before it is their turn to be taken by the
really means that the draft, instead of being gen
eral in the fields between the nips of successive 40 drawing rollers. The result >is that they tend
from time to time to be “plucked” forward in
pairs of drafting rollers, is local. Where there is
thick undrafted bunches, leaving behind them
no draft, a thick portion results and where the
thin portions `composed mainly of the longer
draft is concentrated, athin portion results. The
fibers. These thick bunches of short fibers tend
latter originates at some place within the draft
ing field between the hips of two successive pairs 45 to persist through theentire series of subsequent
drafting operations.
of drafting rollers Where the fiber cohesion is
Another object of the invention is‘the provision
least, and results in the stream of `short fibers
'of means for detecting variations in the density of
being separated into two parts'. The rear part
the fibers of the length of material, and for pro
moves slowly and the front part more rapidly.
The concentration of the draftin the‘rear portion 50 viding an indication of the magnitude of such
variations.
allows the front portion to go forward undrafted,
In carrying the invention into effect in one form
and the rear portion is drafted into a thin por
thereof, a fluid such as air is caused to flow
tion.
Accordingly, a further object of this invention
is the provision of means for controlling the draft
55
through the fibers of a length of material, such
as 'al sliver, of which thefiber density is to be
2,407,100
3
determined. The resistance offered by the array
of ñbers to the flow of air is a measure of the fiber
density, and thus by measuring variations in re
sistance to the flow of air through the liber array,
the amount of variation from uniformity can be
determined.
One form of the device for measuring the re
sistance to flow of air through the fibers com
prises a member provided with a passageway
through which the length of material passes. l
This member is recessed to provide a chamber in
communciation with the passageway.
Air from
a suitable source of constant pressure is supplied
through a restricted orifice to this passageway
and escapes through the fibers. The air pres
sure in the chamber is a measure of the fiber
density of the material passing through the pas
sageway.
In a preferred form of the invention, the mem
ber containing the passageway is provided with a
plurality of chambers which are in fluid com
munication with the passageway.
sents the nega-tive side of the source. An adjust~
able potentiometer type resistor 20 is connected
across the source I8, I9. The shunt field. wind
ings I4a and I6a of the -motors I4 and I6 are
connected in series relationship with each other
across the source, and the armatures of these two
motors are connected in parallel relationship be
tween the positive side I8 of the supply source
and the slider 20a of the potentiometer resistor.
By varying the position of the slider 20a, the
speeds of motors I4 and I6 can be adjusted up~
Ward or downward to a desired level.
For the purpose of varying the relative speeds
of the pairs of drafting rollers I2 and I3, in re
sponse to variations from a predetermined value
in the density of the ñbers in the sliver Iii, a suit
able speed regulating device 2I is provided for
controlling the relative speeds of motors I4 and
I6. This speed regulating device 2| comprises a
stack of disks of a resistance material, such as
carbon. The carbon stack 2I is connected in se
ries relationship with a permanent resistor 22
across the supply source I8, I9, and the common
point 2Ia between the carbon stack 2l and the
resistor 22 is connected to the common point |412
between the field windings I4a and IIia by means `
of a conductor 23. The carbon stack 2| is mount
ed on a support 24 and is provided with a cap 25
to which a rod 26 passing through the center of
Another aspect of this invention is the auto
matic control of the drafting of the length of
material to produce the desired degree of even
ness in the draft and uniformity of the'product.
In this aspect of the invention, a length of ma
terial containing an array of fibers is passed be
tween a pair of drafting rollers which is driven
at a predetermined speed by a suitable driving
the carbon stack is suitably secured. When pres
means and then through another pair of drafting 30 sure is applied to the carbon stack 2 I, as by means
rollers driven at a higher speed. A device such
of a downward pull on the rod 2€, the resistance of
as described in the foregoing for detecting varia
the carbon stack is decreased and conversely,
tions from a predetermined value in the density
when the pressure on the carbon stack is re
of the fiber array passing through the passage
leased, the resistance is proportionately increased.
way is utilized to control the driving means for
From the connections described in the fore
the pairs of drafting rollers to vary the draft in
going, it will be seen that the carbon. stack 2! is
such a manner as to restore the fiber density to
in parallel with the shunt ñeld winding Illa of the
the predetermined value.
motor I4 and in series with the shunt field wind
For a better and more complete understanding 40 ing I6a of the motor I6. Thus, when pressure is
of the invention, reference should now be had to
applied to the carbon stack 2| to decrease its re
the following specification and to the accompany
sistance, the excitation of the shunt field wind
ing drawings of which Fig. 1 is a simple diagram
ing Ma, is weakened and that of the shunt ñeld
matic sketch of an embodiment of the invention;
winding ISa is increased. As a result, the speed
Fig. 2 is a modification; and F‘ig. 3 is an enlarged
of the motor I4 is increased and the speed of the
view in section of the multiple chamber ñow tube ‘ motor I6 is decreased. The increase in the speed
of the modifications of Figs. l and 2.
of the motor I4 and the decrease in the speed of
Referring now to the drawings, a length of
the motor I6 produce corresponding changes in
material I0, such as a sliver, containing an array
the speeds of the pairs of drafting rollers I2 and
of loose fibers, is illustrated as being passed in the
I3, and thereby decrease the draft of the ñbers
direction of the arrow II through the nip of a
in the drafting ñeld between these pairs of rollers.
first pair of drafting rollers I 2, and then through
Likewise, when the pressure on the carbon
the nip of a second pair of drafting rollers I3 to
stack 2I is released to increase its resistance, the
a subsequent stage in the processing. The dis
excitation of the field winding I4a is increased
tance between the nips of the pairs of drafting
and the excitation of the field winding I 6a is cor
rollers I2 and I3 is greater than the length of
respondingly decreased. This causes the speed
the longest fibers in the array which constitutes
of the motor I4 and the drafting rollers I 2 driven
the sliver Ill.
thereby to decrease and the speed of the motor
Although the drafting rollers may be driven by
I6 and the drafting rollers I3 driven thereby to
any suitable driving means, they are preferably
increase. The decrease in the speed of the draft
driven by electric motors. As illustrated, the ñrst lli) ing rollers I2 and the increase in the speed of the
pair of drafting rollers I2 is driven at a suitable
drafting rollers I3 produce an increase in the
speed by means of an electric motor I4 which is
draft of the sliver in the drafting ñeld between
illustrated as a shunt-wound direct-current mo
the two pairs of rollers.
tor to the drive shaft of which the bottom roller
The pressure on the carbon. stack 2l is varied
is connected through suitable driving connections
by means of a pressure responsive diaphragm
illustrated as gearing I5, and the second pair of
device 2l in response to variations in fluid pres-n
drafting rollers I3 is driven at a speed which may
sure produced by a flow tube device 28 in response
be assumed to be ñve times the speed of the first
to variations from a predetermined value in the
pair of rollers by a similar motor I6 through simi
density of the sliver I0. Although the flow tube
lar reduction gearing I 'I.
detecting device 28 may be made in any suitable
The motors I4 and I6 are supplied from a suit
way, .it is illustrated as comprising a pipe T
able direct-current source which is represented in
member 28a which is provided with an insert
the drawings by the two conductors I8 and I9.
28h. The insert member 22D is tapered from. botl'i
The conductor I8 represents the positive side of
ends toward the center to provide a flow tulo-cy
the supply source, and the conductor I9 repre
passageway for the passage of the sliver 513, and
5
.
means. The connections between the yoke 21d
is recessed between the entering and leaving ends
‘ and the pressure applying rod 26 `are such that4 a
of the tube to provide a chamber v28o in_‘commuM
decrease in pressure in chamber 28o produces a
corresponding increase in pressure c-n the carbon
stack, and an increase in pressure in the cham
ber» 28c produces a corresponding decrease in
nication with the passageway through which the
sliver i0 passes.
'
-
A fluid, such as air. is supplied from a suitable
source, _such as the mill supply, through a re
pressure on the stack.
tricted oriñce 29 to the chamber 28C in the flow
tube device 28.
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`
The pressure ofthe air supplied to the cham
ber 28C through the oriiice 29 is maintained sub
stantially constant by means of a pressure regu
1
’
A pressure responsive indicating device, such
as a Bourdon gauge >4l is connected- to the pipe
10 4D leading to the pressure chamber 28o, for the
purpose of providing a Visual indication of the
pressure in the chamber 28oA and the density of
the fibers of the sliver I il passing through the
passageway of the flow tube detecting `device 29.
29. This pressure regulator comprisesa bleed
For the purpose of providing support andre
valve 39a which is loadedby means of a spring 15
30h. The bleed valve 30a is yfastened to one end ` straint of the shorter iibers in the drafting ñelds
between the pairs.of‘drafting‘rollers l2 and I3,
of a lever 30C, the opposite 1end of which is pro
without fracturing the longer fibers in the draft
vided with a knife edge which rests in thebot
ing ñeld, a iiow tube nozzle device 42 is provided.
tom of a .V-shaped‘slot in afblock 30d _to pro
A's shown in Fig. 3, the flowrtube device 42
vide for pivotal mcvementof the Vlever 39o.`> 'One
diifers from the'flowtube device 2B of Fig. 1 in
end of the loading spring 3B?) is 'secured to a sta
that the sizes of the sliver flow passages in the
tionary
and the part,
othersuch.
end for
is attached
example as
to the
a screw
pipe 39e
inSertSrllZa and 42b§in the entering and leaving
ends of the tube are different and also in the pro
which passes through the lever 39e and is pro
vided with a nut 30]“ for adjusting the tension of f vision'of a plurality of internal barriers 42C and
42d which" are substantially equally spaced be
the spring to provide the desired loading of the
tween the ends to provide a plurality of air cham
valve. The valve 306i has a maximum movement
>bers 42e, 42j, and 42g. The barriers 42o and 42d
of approximately 0.003 inch so that the change
are provided with centrally disposed passages
in spring gradient is negligible.
'
lating device 3B, which is included in the pipe
connections between the source and the orifice
With variable inlet air pressure from the sup- .
which are graduated in size such that when cen
trally aligned with the passages in the insert 42a
ply source through‘the throttling valve 327 the
and 42h, a passageway the size of which decreases
spring loading is adjusted for the desired pres
uniformly from‘the entering to the leaving end
sure, and the throttling valve 32 is adjusted to
is provided for the sliver l0. The end inserts 42a
give a small opening of the bleed valve corre
and 42h and the internal barriers may be made
35
sponding to the minimum inlet pressure.` With?
Vof -steel and their surfaces which constitute the
increase in the inlet pressure, the bleed valve
passageway for the sliver may be chromium
opens a very small amount to dispose of the in
plated to minimize resistance to the flow of the
creased iiow passed by the throttling valve and
thereby maintains a substantially constant sup
ply pressure to the orifice 29.
ï
The restricted orifice 29 is preferably mounted
in one arm of a pipe T 33, and a similar restrict~
ed orifice 34 is mounted in the other arm of the
pipe T. This other arm of the pipe T leads to ì
atmosphere through a pipe 35 and _an adjustable ‘
needle valve 36.
p
When the needle valve 36 is completely closed,
there is no flow through the oriñce 34 and the
pressures on both sides of the oriñce 34 are equal
to the supply pressure.
The lower chamber of the diaphragm device 2l
sliver.
Y
3
`
‘
-
-
'
`Air is supplied to the chambers 42e, 421‘, and
42g from a` manifold; 43 which in turn is con
nected by means of a pipe 44 `to the source of reg
ulatedair supply, i. e., to the pipe 3l at` the` out
let endof the regulator 39. „
l..
Y .
.
» '
Thefflow .tube device 42 is mounted in the
drafting ñeld between the ñrst and second pairs
of drafting rollers so that the center line of the
`passageway‘of. the tube is aligned with the nips
of the first and second pairs of drafting rollers.
It is of such‘size that it occupies almost the en
tire space between the ñrst and second pairs of
drafting rollers.
. f
.
'
\
is connected through a pipe 3l and an adjustable
, l With the foregoing understanding of the ele
needle valve 38't0 the pipe 35, and therefore, the
ments and their organization inthe control. the
fluid pressure in the lower chamber is equal to
the regulated supply pressure when valve ,35 is 'f operation will readily be understood from the fol
lowing detailed descriptioni The operation is ini
closed. rFhe upper chamber of the diaphragm
tiated by closing the switch 45 to complete the
device is connected through a pipe 39 to the pipe
connections p of the potentiometer .resistor 29
di) through which air is supplied from the re
acrossthe supply source i8, I9, and thereby to
stricted orifice 29 to the chamber 28e of the iìow
energize and startthe drafting roller driving mo
tube detecting device 28. Consequently, the pres
tors I4 >and I6. By means of a needle valve 36,
sure in the upper chamber of the diaphragm de~
the >control is initially adjusted to a balanced
vice 3l is substantially equal to the pressure in
condition such that when the density of the fibers
chamber 28C. The two diaphragms 2lb and 21o
within the passageway of the flow tube detecting
are mechanically connected together by> means
device 28 has the desired value, the pressure drop
of a yoke 21d which moves to take up a position
A across the restricted orifice 29 will result in a rel
corresponding to the magnitude of the diifer
ative speed of the pairs of drafting rollers I2
ence in pressure in the upper and lower cham
and i3 such as to draft the fibers just that
bers. Since the supply pressure is maintained
amount that will result in delivering drafted
constant, the diaphragm device may therefore be
considered to be responsive to variations in the " sliver of the correct fiber density to the iiow tube
detecting device 28.
pressure in the chamber 28e of the flow tube de
As long as the density of the sliver ñowing
tecting device.
'
l
through the flow tube detecting device 28 remains
As illustrated in Fig. l, the pressure applying
` constant at the desired value the rate of flow of
rod 26 of the speed regulating device 2| is se
air from the chamber 28o in opposite directions
cured to the yoke 21d by suitable fastening
2,407,100
7
through the entering and leaving inserts of the
iiow tube will remain constant and consequently
the pressure in the chamber 28C will remain
constant and the diaphragm pressure responsive
device 21 will therefore not change the pressure i
on the carbon stack 2|. Consequently, the rela
tive speeds of the electric motors I4 and I6 which
drive the first and second pairs of drafting rollers
I2 and I3, respectively, will remain unchanged
as long as the über density of the sliver passing
through the passageway of the now tube detect
ing device 28 remains constant.
the motor IG which drives the drawing drafting
rollers I3 will decrease correspondingly and the
speed of the motor IIi‘I which drives the retaining
drafting rollers I2 will increase. This produces
a decrease in the draft of the fibers in the draft
ing ñeld between the pairs of rollers I2 and I3,
and as a result, the fiber density of the sliver de
livered from the drafting rollers I3 will be in»
creased correspondingly.
When the density of
the ñbers of the sliver within the passageway of
the ñow tube detective device 28 returns to the
normal value, the pressure in the chamber 28e
will be restored to the normal predetermined
»
However, if a relatively thicker portion of the
sliver approaches the detecting device, the den
~sity of the ñbers'entering the passageway of the
ñow tube device 28 tends to increase.
8
ing I 4a of motor I II. As a result, the speed of
value. Likewise the pressure drop across the re
strictedoriñce 29 will be restored to the normal
value and the diaphragm pressure responsive de
vice 21 will again relieve the pressure on the car
bon stack 2| to restore the speeds of the motors
I4 and I6 to the relative values which produce
the required draft of the fibers when the sliver
has the correct fiber density.
The foregoing actions are repeated whenever
the fiber density of the sliver delivered from the
second pair of drafting rollers I3 deviates from
the normal predetermined value.
As a re
sult of this tendency of the liber density to in
crease, the'flow of air from the chamber 23e
through the fibers in both directions will be pro
portionately restricted and this will cause the
pressure in the chamber 28e to increase. The re
sulting increased pressure in the chamber 28e
decreases the pressure drop across the restricted
orifice 29 thereby tending to equalize the pressure
in the upper and lower chambers 21h’ and 21e of
the diaphragm device 21 and permitting the yoke
21d to move upwardly and relieve the pressure on
the carbon stack 2|. The relief of pressure on
the carbon stack 2| causes its resistance to in
Since the pressure in the upper chamber of
the diaphragm device 21 is equal to the pressure
in the chamber 28e and the pressure in the lower
crease correspondingly thereby weakening the 30 chamber of the diaphragm device is equal to the
excitation of the field winding Ita of the motor
_pressure ahead of the orifice 251, the diaphragm
I 5 which drives the second or drawing pair of
device in eiîect balances the pressure in the
drafting rollers I3. As a result of the increase
chamber 23e against the pressure ahead of the
in the resistance of the carbon stack 2 I, the volt
orifice 29 as a reference pressure. By varying
age drop across the carbon stack 2| is increased, 35 the opening of the needle valve 35, the reference
thereby increasing the voltage applied to the ñeld
winding Ida of the motor I4 whichv drives the ñrst
or “retaining" pair of drafting rollers I2. The
decrease of excitation of the ñeld winding IGa
produces a corresponding increase in speed of the 40
motor I6 and conversely the increase in the ex
citation of the field winding I4a produces a cor
pressure with` which the pressure in the chamber
28C is compared can be varied as desired, thereby
to provide for adjustment of the automatic cor
recting means t0 hold any desired value of ñber
density.
Thus the diaphragm pressure device 21 re
sponds to all variations in the pressure within
the chamber 2te produced by deviations of the
ñber density of the sliver from the predetermined
responding decrease in the speed of the motor
As a result, the draft of the ñbersin the
drafting field between the pairs ofrollers I2 and 4. value, to initiate changes in the relative speeds
of the pairs of drafting rollers I2 and I3 to
I3 is increased and the increased draft elongates
counteract such deviations. These deviations
and thins the thick portion of the sliver, and
may occur at such a rate that a hunting action
thereby reduces the fiber density of the sliver de
will be set up. However, this hunting action is
livered to the ñow tube detecting device 28. This
action continues as long as the density of the 50 overcome by adjustment of the needle valve 38
in the pipe connection between the lower cham
sliver is greater than the desired predetermined
ber of the diaphragm device 21 and the pressure
value. When the fiber density of the sliver re
turns to the predetermined desired value, the
pressure in the chamber 28e returns to the nor
mal value and the diaphragm pressure respon
supply source to provide a restriction to the now
of fluid between the source and the lower cham
55 ber.
This produces a dash-pot action which
minimizes the tendency to hunt.
sive device 21 responds to actuate the carbon
The supply of air under pressure from the
stack .".I to restore the original Speed relation
manifold 43 tothe air chambers 42e, 42j, and 42g
ship of the draft roller driving motors I4 and I6.
of the multi-chamber flow tube device 4L' provides
If a portion of the sliver which is relatively
thinner than the normal value approaches the 60 support and restraint for the shorter fibers in the
array of fibers between the pairs of drafting roll
now tube device, the density of the ñbers enter
ers I2 and i3. Owing to the fact that Within the
ing the passageway of the flow tube device tends
air chambers 42e, 42j, and 42g the sliver Iii is
to decrease so that the ñbers will offer less re
sistance to the ñow 0f air from the chamber 28o 65 surrounded by air under pressure, a slipping re
straint or grip is imposed upon the fibers which
keeps the loose or wild ñbers bound into the mass
and creates a condition favorable to consistent
the ~pressure drop across the restricted orifice 29.
and uniform draft.
As a result of the increased pressure drop across
The slipping grip imposed upon the portion of
the orifice 2S, the diaphragm pressure responsive
70 the sliver within the passageway of the flow tube
device 21 will increase the pressure on the car
¿2 b-y the air pressure within the chambers 42e,
bon stack 2| to decrease its resistance. This in
to atmosphere.
This will cause the pressure in
the chamber 28e to decrease, thereby increasing
i321“, and 112g allows the long fibers to be drawn
crease in pressure on the carbon stack increases
forward freely and also allows the short fibers
the excitation of the field winding ISa of motor
entering the second pair of drafting rolls I3 to
I 6 and decreases the excitationof the field wind 75
beA moved forward with respect to the shorter
2,407,106
10
fibers which have not yet entered the drafting
fiber density `of alength >of material without
rolls I3 and thereby provides even and consistent
utilizing variations in the density from a prede
termined value as signals to actuate automatic
controlling mechanism. In such cases, the only
‘ drafting of all the fibers within the drafting field.
In the modification of Fig. 2, the flow tube de-`
tecting device 25 of Fig. l is eliminated, and the functions of the flow tube detecting device 28 and
the flow tube device 42 are performed by a single
multi-chamber flow tube device 4S, which is iden
tical in structure with the flow tube device 42 of
Figs. 1 and 3. This is accomplished by connecting l0
the manifold 41 into one arm of a pipe T 48 which
contains restricted orifices (not shown) in the
upper and lower arms thereof which are identical
apparatus necessary is a flow tube detecting de
vice, a source of constant fiuid pressure for sup
plying fluid to the detecting device, a restricted
orifice in the connection between the source and
the; detecting device, and a device for measuring
and indicating fluid pressure in the detecting
device. The detecting device may be of the same
type as the device 28 or may be of the multiple
chamber type, such as device 42 of Fig. 1, and
maybe located at any point at which it is de
in structure with the corresponding restricted
orifices 29 and 34 of Fig. 1 and perform the same 15 sired to measure the density of the fibers. In
other Words,` for cases in which it is desired only
function. Likewise the throttle valve 49, fluid
pressure regulator 50, the pressure responsive
diaphragm device 5l, the carbon stack motor
speed regulating device 52, and the needle valves
to-measure the density of the fibers, apparatus
same function. The motors which drive the first
the patent statutes this invention is described
in` concrete form and the principle thereof is ex
plained together with the best mode in which it
is now contemplated applying that principle it
will‘be understood that the elements shown and
described are merely illustrative and that the
invention is not limited thereto since alterations
such as is shown in Figs. 1 and 2 may be em
ployed with the pressure diaphragms and speed
53 and 54 are identical in structure Wi-th the cor 20 regulating features omitted.
Although in accordance -withA the provisions of
responding elements in Fig. 1 and perform the
and second pair of drafting rollers 55 and 56 and
their electrical control circuit are omitted from
Fig. 2 in the interest of simplicity. They are iden
tical in structure with the motors of I4 and IB
and associated control circuits respectively of
Fig. 1.
In operation, the diaphragm device 5| responds
to variations in fluid pressure in the chambers
of the multi-chamber iiow tube device 46 which
and modifications will readily suggest themselves
to persons skilled in the art without departing
from the true spirit of this invention or from the
are produced by deviations from a predetermined
scope of the annexed claims.
value in the density of the` fibers of Vthe sliver
within the passageway to actuate the carbon
>What I claim asignew and desire to secure by
Letters Patentof the United States is:
1. In combination, means for'drafting a length
of material containing an arrangement of fibers
stack regulating device; 52 to vary the relative
speeds of the electric motors which drive the
pairs of drafting rolls 55 and 56 in the same
manner as in the previously described operation
of the modification of Fig. 1.
~
'
comprising a ñrst pair of drafting rollers, a sec
ond pair of drafting rollers mounted in spaced
relationship with respect to said first pair of roll- '
Since the ñow tube device 46 of the modifica 40 ers, and means for driving said first pair of roll
ers at a predetermined speed and said second
tion of Fig. 2 is identical with the flow tube device
pair of rollers at a greater speed, a source of sub
‘l2 of the modification of Fig. 1, and since it is
stantially constant fiuid pressure, a member pro
mounted in the same position between the first
viding passageway for said length of material and
and second pairs of drafting rollers 55 and 56,
a chamber connected to said source and in com
it also performs the same function of support
munication with said passageway to provide a
and restraint of the shorter fibers in the drafting
varying fluid pressure in said chamber in response
field without danger of fracturing. the longer
Vto unevenness in successive portions of said length
fibers. Ans in the modification of Fig. 1, a Bour
of material, and means responsive to said varying
don gage 51 or other pressure responsive indi
cating device is employed to provide a visual indi 50 pressure for controlling said driving means to
vary the relative speeds of Asaid pairs of rolls to
cation of the fluid pressure in the chamber of
diminish said unevenness.
the multi-chamber device 46. Since the pressure
2. In Vcombination with means fordrafting a
of the air supplied through the orifice in the pipe
length
of material containing an array of loose
T 48 to the chambers of the device 46 is main
fibers
comprising
first and second pairs of draft
tained constant by means of the pressure regu
ing rollers mounted in spaced relationship
lator 593, the fiuid pressure in the chambers of
through which said length of material passes in
the flow tube device 46 is therefore a measure of
succession,
means for driving one of said pairs
the density of the ñbers of the sliver and conse
of rollers at one speed and the other pair at a
quently the dial of the gage 51 may be calibrated
different speed, a source of substantially constant
in units of ñber density.
60 fluid pressure, a member provided with a passage
In Calibrating the dial o-f an indicating device,
wayfor said length of material having a cham
such as the devices 4I and 5'! of Figs. 1 and 2,
ber. connected to said source and communicating
respectively, it is feasible to use the total fiber
with said passageway for producing variations in
cross-section of the sliver as a measure of density.
fluid pressure in said chamber in response to de
When density is so considered, the calibration is 65 partures in the density of` said length of material
identical for all types of fiber, except for insig
from a predetermined`va1ue,and means respon
nificant differences owing to the variation in the
sive to said Variations >in fluid pressure for vary
air fiow coeñicient caused by variation in fiber
ing the relative speeds of said pairs of drafting surface friction. The density of a given type of
rollers to restore said predetermined `value of
fiber is also frequently measured in terms of 70 density of said length of material.
i
»
weight (in grains) per yard and a different cali
3. In combination with means for drafting a
bration for each type of material is required on "
account of the varying specific gravities of fibers
length `of material containing an array of loose
fibers comprising »first and second pairs of draft
of different materials.
ing rollers mounted in spaced relationship
‘
'
Very- often, it- is desired only to measure the 75 through which saidlength of material passes in
i1
2,407,106
12
succession, means for driving one'of said pairs
way, a member having a restricted oriñee, a source
of rollers at one speed and the other pair at a
different speed, a member providing a passage-_
way for said length of material having a chamber
communicating with said passageway, a source Cl
of substantially constant fluid pressure for sup
plying fluid through said orifice to said chamber
to produce variations in the fluid pressure drop
across said orifice in response to variations from a
of substantially constant fluid pressure for sup
predetermined value in the density of said length
plying a fluid to said chamber, and means re
of material, and means responsive to said varia
sponsive to changes in the resistance of said
tions in fluid pressure drop across said orifice for
length of material to the passage of said fluid for
controlling said driving means to vary the relative
varying the relative speeds of said pairs of draft 10 speeds of said drafting rollers to restore the den
ing rollers to maintain the density of said length
sity of said material to said predetermined value.
of material substantially constant.
8. In combination, means for drafting a length
4. In combination with means for drafting a
length of material containing an array of loose
fibers comprising first and second pairs of draft
ing rollers for said length of material mounted
in spaced relationship, electric motor means for
driving one of said pairs of rollers at a predeter
mined speed and the other pair at a different
speed, a member providing a passageway for said
length of material having a chamber communi
eating with said passageway, a source of substan
tially constant fluid pressure for supplying fluid
to said chamber to provide variations in the pres
sure in said chamber corresponding to variations
in the density of said material from a predeter
mined value, and means responsive to said pres
sure variations for controlling said motor means
to vary the relative speeds of said pairs of rollers
to restore the density of said material‘to said
predetermined value.
5. In combination with means for drafting a
length of material containing an array of loose
fibers, comprising first and second pairs of draft
ing rollers for said length of material mounted
in spaced relationship, a first electric motor for
driving said ñrst pair of rollers at a predeter
mined speed, a second electric motor for driving
said second pair of rollers at a, different speed,
a member providing a passageway for said length
of material having a chamber communicating
with said passageway, a source of substantially
constant pressure for supplying a iiuid to said
chamber to provide variations in fluid pressure
corresponding to variations from a predetermined
value in the density of said length of material,
and means responsive to said pressure variations
for varying the relative speeds of said motors to
restore the density of said length of material to
said predetermined value.
6. In combination with means for drafting a
length of material containing an array of loose
fibers comprising first and second pairs of draft
ing rollers for said length of material mounted in
spaced relationship, driving means for said pairs Ui Ul
of rollers, a member mounted between said pairs
of rollers providing a passageway for said length
of material and having a chamber communicating
with said passageway, a source of substantially
constant fluid pressure for supplying fluid to said
chamber to produce variations in ñuid pressure
corresponding to variations from a predetermined
value in the density of said length of material,
and means responsive to said variations in fluid
pressure for controlling said driving means to
vary the relative speeds of said drafting rollers
to restore the density of said length of material
to said predetermined value,
7. In combination, means for drafting a length
of material containing an array of loose fibers
of material containing an array of loose fibers
comprising first and second pairs of drafting
rollers for said length of material, driving means
for said pairs of rollers, a member mounted be
tween said pairs of rollers provided with a pas
sageway for said length of material and having
a chamber communicating with said passageway,
a member having a restricted orifice, a source
of substantially constant fluid pressure for sup
plying fluid through said orifice to said chamber
thereby to produce variations in the pressure drop
across said orifice corresponding to variations
from a predetermined value in the density of said
length of material, and means responsive to said
variations in pressure drop for controlling said
driving means to vary the relative speeds of said
drafting rollers to restore the density of said
length of material to said predetermined value.
9. In combination, means for drafting a length
of material having an array of loose ñbers com
prising first and second pairs of drafting rollers
for said length of material, driving means for said
rollers, a member provided with a passageway for
said length of material recessed to provide a plu
rality of chambers between the inlet and outlet
of said member communicating with said pas
sageway, a source of substantially constant fluid
pressure for supplying fluid to said chambers
thereby to produce a variation in the fluid pres
sure in said chambers in response to variations
from a predetermined value in the density of said
length of material, and means responsive to said
variations in fluid pressure for controlling said
driving means to vary the relative speeds of said
pairs of rollers to restore said predetermined
value of density.
l0. In combination, means for drafting a length
of material having' an array of loose fibers com
prising first and second pairs cf drafting rollers
for said length of material, driving means for said
rollers, a member provided with a passageway for
said length of material recessed to provide a plu
rality of chambers between the inlet and outlet
of said member communicating with said pas
sageway, a member having an orifice, a source of
substantially constant fluid pressure for supply
ing ñuid through said orifice to said chambers
thereby to produce variations in the fluid pres
sure drop across said orifice in response to varia
tions from a predetermined value in the density
of said length of material, and means responsive
to said variations in pressure drop for control
ling said driving means to vary the relative speeds
of said pairs of rollers to restore the density of
said material to said predetermined value.
11. In combination, means for drafting a length
of material containing an array of ñbers com
prising ñrst and second pairs of drafting rolls
for said length of material, driving means for said
pairs of rollers, a member mounted between said
comprising first and second pairs of drafting
rollers for said length of material, driving means
for said pairs of rollers, a member providing a
pairs of rollers having a passageway for said
passageway for said length of material and hav
length of material and recessed to provide a plu
ing a chamber communicating with said passage 75 rality of chambers surrounding said passageway
2,407,100
13
and communicating therewith, a source of sub
stantially constant iiuid pressure for supplying
fluid to said chambers thereby to produce varia-_
tions in fluid pressure in response to variations
from a predetermined value in the density of said
material for controlling said driving means to
vary the relative speeds of said pairs of drafting
14
rice, a source of substantially constant fluid pres
sure for supplying fluid through said orifice to
said chamber to produce variations in pressure
drop across said orifice in response to departures
Cîl of the density of said material from a predeter
mined value, a pressure responsive device con
nected across said orifice for responding to said
variations in pressure drop to control said driv
ing means to vary the relative speeds of said pairs
said predetermined value,
12. In combination, means for drafting a length 10 of rolls to` restore the density of said material to
said predetermined value, and anti-hunting
of material containing an array of fibers com
means comprising a variable restriction in the
prising first and second pairs of drafting rollers
connections between said pressure responsive de
for said material, driving means for said pairs of
vice and said orifice.
rollers, a member provided with a passageway for
‘
ERNEST L. RICHARDSON.
said length of material and recessed to provide
rollers to restore said density of said material to
a chamber in communication therewith, an ori
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