U.S. patent number 3,699,768 [Application Number 05/118,320] was granted by the patent office on 1972-10-24 for elastic metal filament yarn.
This patent grant is currently assigned to Brunswick Corporation. Invention is credited to James E. Kelly, John A. Roberts, Peter R. Roberts.
United States Patent |
3,699,768 |
Roberts , et al. |
October 24, 1972 |
ELASTIC METAL FILAMENT YARN
Abstract
An elastic metal filament yarn, compatible with any natural
and/or synthetic filamentary yarn or composite material, consisting
of a plurality of outer peripheral metal filaments and at least one
central metal filament located along the axis of the filament yarn,
where said outer filaments are helically twisted around the yarn
axis defining a void therein, wherein the outer metal filaments
will collapse toward the central filament when axial tension is
applied to the yarn.
Inventors: |
Roberts; John A. (North
Chelmsford, MA), Roberts; Peter R. (Groton, MA), Kelly;
James E. (Burlington, MA) |
Assignee: |
Brunswick Corporation
(N/A)
|
Family
ID: |
22377868 |
Appl.
No.: |
05/118,320 |
Filed: |
February 24, 1971 |
Current U.S.
Class: |
57/213; 57/217;
57/244; 57/901; 57/210; 57/243; 57/250; 57/902 |
Current CPC
Class: |
D02G
3/12 (20130101); D02G 3/48 (20130101); D07B
1/0633 (20130101); D07B 1/062 (20130101); Y10S
57/902 (20130101); D07B 2401/2005 (20130101); D07B
2201/2059 (20130101); Y10S 57/901 (20130101) |
Current International
Class: |
D02G
3/48 (20060101); D02G 3/12 (20060101); D07B
1/06 (20060101); D07B 1/00 (20060101); D02g
003/12 () |
Field of
Search: |
;57/34R,34AT,35,14BY,144,145,146,147,149,157AS,160,161,163,164,168
;28/76T |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schroeder; Werner H.
Claims
What we intend to claim and secure by Letters Patent of the United
States, is:
1. An elastic filament yarn comprising:
a plurality of outer filaments preselectively arranged in
substantially the peripheral region of the filament yarn and
further defining a void therein, said outer filaments helically
twisted with respect to the central axis of said void; and
at least one central filament centrally located along the central
axis of said void;
wherein the central filament is breakable upon application of
sufficient axial tension and the outer filaments are reversibly
moveable through the void toward the central filament thereby
permitting the filament yarn to be reversibly geometrically
elongatable.
2. An elastic filament yarn as recited in claim 1 wherein the outer
filaments and central filament are made of metal.
3. An elastic filament yarn as recited in claim 2 wherein the
central filament can be stressed to its ultimate tensile stress and
broken prior to stressing the outer filaments to their tensile
yield stress.
4. An elastic filament yarn as recited in claim 1 wherein the
plurality of outer filaments are preselectively arranged in the
filament yarn prior to being helically twisted around said central
axis, such that upon application of axial tension along said
filament yarn the outer filaments will geometrically elongate
uniformly and be substantially equally stressed.
5. A yarn having a plurality of filaments comprising:
at least one central filament centrally located along the central
axis of said yarn and breakable upon application of sufficient
axial tension;
an expendable matrix material surrounding said central filament;
and
a plurality of outer filaments surrounding said expendable matrix
material in a preselected arrangement and helically twisted with
respect to the central filament, said outer filaments substantially
defining the peripheral region of said yarn, wherein the expendable
matrix material is removeable from the yarn, resulting in a yarn
having a void left between the outer filaments and central filament
defining space through which the outer filaments can reversibly
move toward the central axis yarn application of sufficient axial
tension to break said central filament.
6. A filament yarn as recited in claim 5 wherein the expendable
matrix material is made of a leachable metal material and the outer
filaments and central filament are made of a non-leachable metal
material.
7. A filament yarn as recited in claim 6 wherein said outer
filaments are preselectively arranged in the peripheral region of
said yarn matrix prior to being helically twisted around said
central axis.
8. A textile material comprising:
an elastic metal filament yarn plied with organic yarn, said metal
filament yarn comprising;
a plurality of outer filaments preselectively helically twisted
filament yarn and defining a void therein; and
at least one central filament centrally located along the central
axis of said void;
wherein said elastic metal filament yarn has geometric elongation
properties substantially equal to the elongation properties of the
organic yarn, thereby making them compatible with each other.
9. A textile material as recited in claim 8 wherein said elastic
metal filamentary yarn has geometric elongation properties less
than the elongation properties of the organic filamentary yarn.
10. A textile material as recited in claim 8 wherein said elastic
metal filamentary yarn has geometric elongation properties greater
than the elongation properties of the organic filamentary yarn.
11. An elastic yarn comprising:
a plurality of helically twisted flexible resilient exterior
filaments wherein the internal surface thereof defines a central
core passage parallel with the axis of the yarn;
at least one central core filament in the passage in a spaced
relationship with respect to the internal surface of the filaments;
and
means for preventing the helical filaments from becoming untwisted
when an axial load is applied thereto.
12. A plurality of helically twisted exterior filaments wherein the
internal surface thereof defines a central passage parallel to the
axis of the yarn;
at least one central core filament in the passage in a spaced
relationship with respect to the internal surface of the helical
filaments; and
a matrix material substantially surrounding the core filament and
filling the passage, the matrix material capable of being
sacrificially removed from the helical filaments and the core
filament.
Description
FIELD OF THE INVENTION
The present invention relates to a new and novel elastic metal
multi-filament yarn for blending with and reinforcing natural
and/or synthetic composites, fabric, and textile materials. For
example, it could be used with any composition of organic material
used for fabric in clothes, for use in fuel hose lines, as well as
being directly used as tire cord. The metal yarn incorporates a
plurality of outer filaments helically twisted around a central
filament, defining a void therebetween, such that upon breaking the
central filament the metal filament yarn is highly elastic under
low tension, by translating toward the center until reaching the
central filament, after which further tension will induce high
stress and low elongation.
In particular the idea of the present invention provides for the
ability to predeterminatively control the characteristics of
elongation in the metal filament yarn by preselectively arranging
the metal filaments in the outer region of a filament yarn matrix
surrounding a sacrificial inner matrix material subsequently
removed therefrom with the sacrificial or expendable inner matrix
material having a centrally located non-expendable filament
therein, such that any desired percentage of geometric elongation
with the optimum mechanical properties of the filament yarn may be
obtained. In this way any specified amount of geometric elongation
can be designed into the metal yarn to make it compatible with the
elongation characteristics of any particular composition of natural
and/or synthetic yarn or fabric. By geometric elongation and
elasticity is meant reversible changes in length of the filament
yarn due to a change in geometry of the configuration in which the
filament yarn is set.
DESCRIPTION OF THE PRIOR ART
One of the major problems in using single strand metal filament
with natural or synthetic yarn is the lack of stress and elongation
compatibility between the metal and organic filaments. It is well
known that organic filaments and fabric undergo a great amount of
elongation at low tension levels. Alternatively, a single metal
filament is known to have little elongation at similar tension
levels. It would be desirable therefore to attempt to incorporate
the physical properties of metal filaments as a reinforcing element
in organic fabric for improved strength and wear qualities, crush
characteristics, and better pile structure, taking advantage of
both the strength and wear properties of the metal filaments and
the high elongation and soil-hiding properties of organic material.
However, attempts at combining single and multiple metal filaments
with organic yarn have met with little success, not only because of
elongation incompatibility, but also because the fabrication
process manipulating the metal filament results in a material with
a loose metal filament weave that gains little advantage from the
metal filament physical properties.
A few patents describing different embodiments of coreless yarn
having a certain amount of elasticity are U.S. Pat. Nos. 3,399,521;
3,090,189; 3,189,499; 3,344,596; and 2,587,117. Some of these
describe using elastic and inelastic threads for the yarn core,
others talk of texturizing or processing the yarn to obtain
elasticity by a volume increase, and still others teach using
prestressed elastic threads for the yarn core surrounded by a layer
of inelastic outer strands. However, nowhere has the prior art
shown attempts or ability to predeterminatively design and control
the amount of elongation, density, and/or weight of the resulting
elastic yarn. It was desired in the manufacture of elastic yarn to
be able to design into the cored yarn those elongation
characteristics necessary to suit any particular composition of
natural and/or synthetic fibers.
Although desirable, no prior art yarn or processes for making them,
have the ability to predeterminatively design into the yarn those
optimum physical properties and characteristics making it
compatible in geometric elongation, density, and weight (and any
variation thereof), with natural and/or synthetic fabrics.
SUMMARY OF THE INVENTION
The present invention then is generally intended to overcome the
deficiencies of the prior art and to provide for a high strength
metal filament yarn geometrically elastic at tension levels
normally encountered in natural or synthetic filaments or
fabric.
It is accordingly a general object of the present invention to
provide for the ability to predeterminatively control the geometric
elongation characteristics in elastic metal yarn by a preselective
arrangement of metal filaments in the outer region of a filament
yarn matrix.
Another object of the present invention resides in the provision of
forming an elastic metal yarn, having its outer filaments equally
stressed upon application of axial tension, by preselective
arrangement of the outer filaments in a filament yarn matrix,
thereby optimizing the maximum strength of elongation of the
filament yarn.
A further object of the present invention resides in the provision
of an elastic metal yarn having elongation characteristics
compatible with the elongation characteristics of natural and/or
synthetic yarn or fabric.
A feature of the resent invention provides for a metal filament
yarn matrix that can have a preselected filament yarn to
sacrificial matrix material ratio and filament arrangement thereby
permitting design of the exact filament density and weight desired
in the outer region of the resulting elastic metal yarn.
Another feature of the present invention resides in the provision
of utilizing a central unstressed metal filament in the yarn that
is manipulated during the sewing process thereby eliminating the
problem of stretching of the elastic filament yarn during the
manufacturing process, the central filament being broken after
material fabrication thereby permitting the metal yarn to
compatibly stretch with the natural and/or synthetic fabric.
A further feature of the present invention provides for an elastic
metal filament yarn that can be compatibly piled with natural
and/or synthetic fiber or material as a reinforcing element to
improve the strength and wear qualities or the natural and/or
synthetic material.
Another feature of plying the elastic metal filament yarn of the
present invention with natural and/or synthetic material resides in
the ability to control and eliminate any static electricity
developed in the natural and/or synthetic material.
The novel features which are believed to be characteristic of this
invention are set forth with particularity in the appended claims.
The invention itself, however, together with further objects and
advantages thereof will best be understood by reference to the
following description taken in connection with the accompanying
drawings, in which:
FIG. 1 is a perspective view of the filament yarn embodying the
invention;
FIG. 2 is a cross-section of the filament yarn under no axial
tension, showing the general arrangement of the outer filaments
preselectively arranged around a sacrificial inner matrix and
centrally located filament;
FIG. 3 is a cross-section of the filament yarn under axial tension
showing the general arrangement of the filaments after they have
collapsed through a central void left after removing the
sacrificial inner matrix;
FIG. 4 is a photomicrograph at 50.times. magnification showing a
final configuration of the filament yarn matrix, as described in
FIG. 3, after hot forming and cold drawing but prior to leaching
out of the sacrificial inner matrix material;
FIG. 5 is a photomicrograph at 200.times. magnification showing a
final configuration of another arrangement of a filament yarn
matrix, prior to leaching out the sacrificial inner matrix
material; and
FIG. 6 is a filament identification code.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the preferred embodiment of the present invention, a metal
filament yarn generally designated 10 of filaments 12, as shown in
FIG. 1, is formed by a process described in detail in U.S. Pat. No.
3,394,213, and U.S. Pat. No. 3,505,039. Broadly, these inventions
comprehend the constriction of the bundled wires, by first forming
the bundled wires or elements forming constrictions and subsequent
cold drawing constrictions. The hot forming constrictions may be
alternatively hot extrusion or hot rolling of the billet. The
drawing operation may comprise a plurality of cold drawing steps
with intermediate annealing steps.
The metal filament yarn of the present invention then is the
product of appropriate bundle-drawing, twisting and leaching
process of a metallic yarn matrix with a hollow core being
developed and containing at least one central metal filament, the
overall configuration of this yarn matrix being such, that the yarn
structure is capable of a predetermined amount of geometric
elongation before the individual filaments become highly
stressed.
Referring to FIG. 2, the filament yarn 10 is initially formed in a
sheath 22 which generally consists of a leachable filament matrix
material 16 and non-leachable outer filaments 12. It will be
noticed that there is at least one central non-leachable filament
14 which is necessary to the functioning of the present invention.
The filaments 12 of the metal filament yarn 10 are further
helically twisted with respect to a central filament 14 located
along the longitudinal axis of filament yarn 10. This helical twist
being set into the outer filament 12 during one of the last drawing
steps as described in the prior inventions referred to. This
results in the outer filaments 12 being held in spaced concentric
helices around the matrix material 16 until the matrix material is
removed in the leaching step, which can be chemical attack of the
sheath 22 and matrix material 16. Obviously, other methods of
removing the sheath and matrix material may be employed, such as
those described in the inventions referred to.
Around central filament 14 is arranged in matrix form a plurality
of leachable filaments 16, that will leave a core or void 13 as
shown in FIG. 1, between the non-leachable filaments 12 and central
filament 14 after the leaching process. It should further be noted,
that the non-leachable filaments 12 are arranged in substantially
the outer region or periphery of the metal filament yarn matrix 10.
Dispersed within this outer ring of non-leachable filaments 12 as
shown in FIGS. 2, 3, 4, and 5, are leachable spacers 20 similar to
filaments 16. The leachable filaments 16 are for the purpose of
providing for uniform deformation of the filaments 12 and central
filament 14 during the processing step and room for movement of
filaments 12 after leaching, so that all filaments 12 will collapse
and stretch approximately the same amount during axial tension of
the filament yarn. By rearranging the leachable filaments 16 in the
inner region of the metal filament yarn 10, the ultimate tensile
strength, density and weight can be varied and predetermined in the
final resulting filament yarn. The spacer filaments 20 fill up the
space in sheath 22 not occupied by the filaments 12, 14, and 16 in
the hexagonal array, to assure uniform deformation of the filaments
12, 14, and 16 during processing takes place as described in the
patents referred to earlier.
It has been determined theoretically and proven by experiments,
that allowing for changes in filament diameter after leaching, and
changes in filament position and number of twists per inch after
stretching, it can be shown that: ##SPC1##
where:
R.sub.0 = the initial helix radius, in units of filament diameter,
defining the initial filament diameter position when in an
untensioned state;
R.sub.1 = the final helix radius, in units of filament diameter,
defining the final filament diameter position when under tension
##SPC2##
L.sub.0 = original filament yarn length,
L.sub.1 = final filament yarn length,
D.sub.0 = initial filament diameter,
D.sub.1 = filament diameter after leaching,
n.sub.0 = initial number of twists per inch,
A = 2.pi..
Referring to FIG. 6, the radius R of the helix, denoting the
positions A, B, C, D, etc. in the hexagonal array in Table I, is
taken as Ro when referring to the filaments 12 when in an
untensioned state as shown in FIGS. 1 and 2, and the radius R is
taken as R.sub.1 when referring to the filaments 12 when under
tension as shown in FIG. 3.
The values of R.sub.0 and R.sub.1 therefore, give the locations of
filaments in a filament yarn matrix, as shown in the filament
identification code given in FIG. 6, before and after stretching,
for a given size, elongation, and initial helical twist. Some
values for R.sub.0 and R.sub.1 are shown in a portion of the
hexagonal array Table 1, as examples, for the variety of filament
positions. The initial filament diameter, D.sub.0, includes the
leachable cladding material sheath 15 around the filament 12,
(shown in FIG. 2 as an example) as described and shown in the
patents referred to earlier.
TABLE 1
R.sub.0 and R.sub.1 For Various Positions in Hexagonal Array
Where R.sub.0 X(Initial Filament Dia.) = Initial Radius of
Helix
Where R.sub.1 X(Final Filament Dia.) = Final Radius of Helix
Position Position Position Position R.sub.o or R.sub.1 R.sub.0 or
R.sub.1 R.sub.0 or R.sub.1 R.sub.0 or R.sub.1 A = 0.0000 F.sub.1 =
4.5826 H.sub.1 = 6.5574 K.sub.5 = 8.6603 B = 1.0000 F = 5.0000 H =
7.0000 K.sub.4 = 8.7178 C.sub.1 = 1.7371 G.sub.3 = 5.1962 I.sub.3 =
7.0000 K.sub.3 = 8.8882 C = 2.0000 G.sub.2 = 5.2915 I.sub.2 =
7.2111 J = 9.0000 D.sub.1 = 2.6457 G.sub.1 = 5.5677 I.sub.1 =
7.5498 K.sub.2 = 9.1652 D = 3.0000 H.sub.3 = 5.5677 J.sub.4 =
7.8102 K.sub.1 = 9.5394 E.sub.2 = 3.4610 G = 6.0000 J.sub.3 =
7.9372 L.sub.5 = 9.5394 E.sub.1 = 3.6055 I.sub.4 = 6.0827 I =
8.0000 L.sub.4 = 9.6436 E = 4.0000 H.sub.2 = 6.2450 J.sub.2 =
8.1853 L.sub.3 = 9.8488 F.sub.2 = 4.3589 H.sub.1 = 6.5574 J.sub.1 =
8.5400 K = 10.0000
since the resulting outer filaments 12 will be of unequal distance
from the central filament 14, axial tension of the filament yarn
will induce unequal loading of the individual filaments 12. This
becomes very serious when there is a high degree of twist, for
example 20 turns per inch or more, resulting in the outer filaments
12a being much longer than the outer filaments 12b which are closer
to the center of the filament yarn. The outer filaments 12a will
therefore become loaded only after the closer filaments 12b have
been stressed beyond their yield point or have been broken.
Ideally, all outer filaments 12 should be loaded equally and
simultaneously. The unequal loading problem due to both the unequal
distance of the filaments 12 from the filament axis and the high
degree of twist given to the filament yarn 10, can be minimized
according to the equation given, and thereby optimize combinations
of strength and elongation in the finished filament yarn 10. This
can be obtained by a detailed calculation of the starting billet
configuration, by first selecting a desired elongation E, for given
diameters D.sub.0 and D.sub.1, and calculating R.sub.0 values for
various R.sub.1 locations and degrees of twist. By matching these
R.sub.0 values with R values of the standard hexagonal array (see
Table 1), an initial billet configuration can be determined.
Because of the large number of filaments in any useful filament
yarn design, it is not possible to conform precisely in all cases
to the calculated R.sub.0 position for each filament. For this
reason, adjustments in degree of twist may be necessary to achieve
optimum strength and elongation properties in the final yarn.
Several different billet configurations were calculated and
processed according to the equation given, directed to producing
uniformity of loading in the outer filaments 12 of the finished
filament yarn 10, and mechanical tests of the resultant filament
yarn showed elongation in the ranges predicted, with substantially
equal load distribution among the outer filaments 12 during
geometric elongation.
FIG. 2 shows the arrangement of the outer filaments 12 in the
filament yarn 10, in an unstressed state. Application of tension
will cause the filaments 12 to move through the void 13 (see FIG.
1) defined after the leachable filaments 16 are removed. FIG. 3
shows the filament yarn 10 under axial tension and depicts the
hexagonal arrangement of the filaments 12 in their most dense
configuration, this configuration optimizing the strength of the
filament yarn 10 by equalizing the tension on the individual
filaments 12.
One example of the formation of filament yarn of the present
invention is as follows. The filaments 12c comprised 304 stainless
steel wire 0.080 inch in diameter. The sheath 15c was a Monel 400
tube having a 0.115 inch outside diameter, and a 0.100 inch inside
diameter. The case 22c was formed of mild steel having a 1.221 inch
outside diameter and 1.059 inch inside diameter. One hundred and
fifty six (156) of the sheathed filaments 12c, 154 of the leachable
filaments 16c, and one central filament 14c were placed in the case
22c in the arrangement shown in FIGS. 2 and 5, with proper spacers
20c and the case 22c evacuated to less than 0.1 microns of mercury
at 800 degrees F. and sealed off. The billet or filament yarn
matrix 10c was then heat treated at 1,800 degrees F. for six hours
in a graphite container. The resulting composite was reduced in
diameter 17.times. by extrusion and subsequently cold drawn to a
final diameter with intermediate anneals (2 sec/mil at 1,800
degrees F.) as required. After twisting in the final draw to 0.0225
inch diameter with 10 turns per inch, the Monel matrix was leached
out using standard procedures, to form the filament yarn, having an
average geometric elongation of 20 percent and an average ultimate
tensile strength of approximately 21,000 p.s.i.
The case 22 and matrix material 16 was removed by means of nitric
acid.
Another example of the forming of filament yarn of the present
invention comprises the following. Here the filaments 12d were 304
stainless steel wires 0.080 inch in diameter. The sheath 15d was a
Monel 400 tube having a 0.115 inch outside diameter and a 0.100
inch inside diameter. The case 22d was formed of mild steel having
a 2.00 inch outside diameter and 1.838 inch inside diameter. Five
hundred and seventy-one of the sheathed filaments 12d (shown in
FIG. 4), 569 of the leachable filaments 16d, and one central
filament 14d were placed in case 22d in the arrangement shown in
FIG. 4, with proper spacers 20d and the case 22d evacuated to less
than 0.1 microns of mercury at 800 degrees F. and sealed off. The
resulting billet or filament yarn matrix 10d was then heat treated
at 1,800 degrees F. for 6 hours in a graphite container. The
resulting composite was reduced in diameter 16.times. by extrusion
and subsequently cold drawn down to final diameter with
intermediate anneals (2 sec/mil at 1,800 degrees F.) as required.
After twisting in the final cold draw to 0.40 inch diameter with 9
turns per inch, the Monel matrix was leached out using standard
procedures, to form the filament yarn, having an average elongation
of 20 percent and an average ultimate tensile strength of
approximately 45,815 p.s.i.
The two examples of the above described yarn matrix configurations
prior to leaching of the expendable matrix material, are shown in
FIGS. 4 and 5. FIG. 4 is a photomicrograph at 50.times.
magnification of a cross-section of a filament yarn matrix in a
sheath 22d having 570 stainless steel outer filaments 12d and one
central filament 14d. The expendable matrix filaments 16d, as can
be seen, have somewhat become uniform during the processing of the
filament yarn matrix. This is also true of the expendable spacer
filaments 20a. FIG. 5 is a photomicrograph at 200.times.
magnification of a cross-section of a filament yarn matrix in a
sheath 22c having 156 outer filaments 12c, one central filament
14c, and a uniform distribution of expendable matrix filaments 16c.
The expendable spacer filaments 20c, have also fused together
somewhat.
As indicated briefly above, the present invention comprehends the
idea of arranging a filament matrix having at least one central
metal filament surrounded by a plurality of helically twisted
filaments in the periphery of the filament matrix with a void
therebetween left upon leaching out the leachable inner matrix
material.
Not only can the filament yarn of the present invention be
predesigned for compatibility with any composition of natural
and/or synthetic yarn or fabric, the filament yarn can also be
directly used in tires as a reinforcing tire cord. Finally, being
electrically conductive, the metal filament yarn permits the
control of static electricity developed in the material in which it
is used. One example of this is using it in fuel hose lines where
static electricity is developed by the movement of fuel through the
hose. The metal filament yarn in this case can conduct the
electricity to ground eliminating the hazard of electrical arcing
and possible fuel ignition.
According to the equation given, the experimental results showed
that a higher twist-per-inch will give a greater degree of
geometric elongation. For a given configuration of filaments 12 and
for a given size of initial filament diameter, D.sub.0, of
filaments 12, there is an optimum twist per inch that will give
optimum properties to the filament yarn 10. For a given number of
turns per inch, the larger the initial starting metal filament
matrix, the greater amount of geometric elongation. Higher ultimate
tensile strengths can be obtained through cold working the filament
yarn matrix prior to twisting, but with a corresponding reduction
in percent elongation.
While we have shown and described specific embodiments of the
present invention, it will, of course, be understood that other
modifications and alternative constructions may be used without
departing from the true spirit and scope of this invention. We
therefore intend by the appended claims to cover all such
modifications and alternative constructions as fall within their
true spirit and scope.
* * * * *