Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BRAIDER APPARATUS WITH IMPROVED BOBBIN HOLDER
TECHNICAL FIELD
The present invention relates to a device for braiding fine
denier yarns and, more particularly, to an improved b.raider bobbin top
holder particularly suited for use with a device for braiding fine denier
yarns to make surgical sutures.
BACKGROUND OF THE INVENTION
Braided products and apparatus for production of such products
are well-knows. Typical of the braiding mechanisms used for such
products sre disclosed in U.S. Patent Nos. 776,842 to Horwood, 1,154,964
to Bentley, 1,285,451 to Stanton, 1,358,173 to Penso et aP., 1,486,527 to
Larkin, 1,785,683 to Mallory, 2,079,836 to Brown et al., 2,200,323 to
Barrans et al., 2,452,136 to Marti, 4,158,984 to Griffiths, 4,304,169 to
Cimprich et al., 4,333,380 to Kozlowski, 4,716,807 to Fischer, 4,753,149
to Celani, 4,909,127 to Skelton et al. and 4,922,798 to Ivsan. British
Patent Publication No. 138,069 dated September 2, 1920 relates to
improvements in such braiding devices.
Sutures intended for the repair of body tissues must meet
certain requirements: they must be substantially non-toxic, capable of
bein~ readily sterilized, they must have good tensile strength and have
acceptable knot-tying and knot-holding characteristics and if the sutures
are of the bio-absorbable variety, the bio-absorption of the suture must
be closely controlled.
Sutures have been constructed from a wide variety of materials
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including surgical gut, silk, cotton, polyolefins such as polypropylene,
polyamides, polyesters such as polyethylene terephthalate, polyglycolic
acid, glycolide-lactide copolymer, etc. Although the optimum structure
of a suture is that of a monofilament, since certain materials of
construction would provide a stiff monofilament suture lacking acceptable
handling, knot-tying and knot-holding properties, sutures manufactured
from such materials have been provided as braided structures. Thus, for
e~ample, sutures manufactured from silk, polyamide, polyester and
bio-absorbable glycolide-lactide copolymer are usually provided as
multifilament braids.
Currently available braided suture products are braided on
conventional braider apparatus having yarn bobbin carriers which travel
around the perimeter of a braider deck to result in a tubular type braid
with the yarns crossing over each other on the surface of the braid. In
larger suture sizes, e.g., 5/0 and larger, the tubular braid, or sheath,
is constructed about a core structure which is fed through the center of
the braider. Known tubular braided sutures, including those possessing
cores, are disclosed, e.g., in U.S. Patent Nos. 3,187,752; 3,565,077;
4,014,973; 4,043,344; and 4,047,533.
Recent attempts to improve the flexibility, hand and tissue drag
characteristics of braided sutures have resulted in new braid structures
possessing a significantly greater number of sheath yarns for a given
overall denier, the sheath yarns being fabricated from individual
filaments of finer denier than filaments which are typical of known types
of braided sutures. Braided sutures of this type are disclosed and
claimed in U.S. Patent 5,019,093. The foregoing patent discloses
sutures braided from yarns having a denier in the range of about 0.2 to
6.0 and, optionally, a core having a denier of from about 50 to about
2500 denier.
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SUMMARY OF THE INVENTION
The present invention relates to an improved apparatus for
braiding elongate flexible members to form a final braided product,
preferably a surgical suture made from fine denier yarns. The braided
product may be of the type formed only of a tubular braided sheath, a
substantially solid spiroid braid, or a tubular or spiroid braided sheath
formed about a center core. In particular, the present invention is
directed to improvements which make it possible to quickly mount and/or
remove a yarn bobbin onto or from a yarn bobbin carrier with high
efficiency and speed and to secure the bobbin to the carrier with a
securing mechanism which is simple to operate, does not require a high
level of dexterity, and which is not tiring or injurious to the muscles
of the operator.
In the braider apparatus of the present invention a plurality of
yarn bobbin carriers move about a main carrier support plate to dispense
yarns toward a braiding zone where the yarns are braided together to form
a final braided product, preferably a surgical suture. The preferred
apparatus includes means for controlling tension on the yarns dispensed
from the bobbins to form the braided suture product and to control the
tension on the final braided product. Each yarn carrier includes a
spindle onto which a novel molded bobbin having a central aperture is
mounted for rotational movement relative to the spindle. Each bobbin has
a number of radial segments engageable with a pawl on the carrier for
selectively permitting rotation of the bobbin in response to yarn tension
in order to control the dispensing of yarn from the bobbin.
In accordance with the invention, a bobbin top holder base is
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fixedly mounted relative to the yarn carrier adjacent the! top of the yarn
carrier spindle and, hence, adjacent to the top of a bobbin situated
thereon. The bobbin top holder base has hinge pins, and a bobbin top
holder is hingedly mounted to the bobbin holder base at the hinge pins.
The bobbin top holder has two longitudinally extending legs defining a
slot therebetween and, more specifically, a spindle engaging recess
having an inwardly projecting radiused section to engage a corresponding
circumferential recess in the spindle adjacent the spindle tip. The
bobbin holder legs are formed of a resilient plastic material which is
sufficiently fle~ible to permit the legs to spread apart as the legs are
forced over the spindle tip, and resiliently reassume a rest position
disposa~ within the circumferential recess of the spindle to hold the
bobbin on the spindle.
In use, the bobbin top holder first is disposed in an unlocked
or open position rotated away from the spindle to permit mounting of a
bobbin loaded with yarn onto the carrier. After the bobbin is mounted,
the bobbin top holder is rotated into contact with the spind~e tip with
sufficient force tn cause the bobbin top holder legs to spread apart and
mount ovar the spindle, resiliently resuming a rest or contracted
position disposed t~ithin the circumferential recess oi the spindle tip,
thereby securing the bobbin on the carrier. The braider apparatus
th~reafter is operated to form a final braided product, preferably a
surgical suture. In order to remove an empty bobbin, suf~icient upward
force is e~erted on the bobbin holder legs to cause the bobbin legs to
spraad apart, leave the spindle recess, and become disengaged from the
spindle. The preferred bobbin holder is injection molded of an
elastomeric plastic material which is sufficiently resilient to permit
many cycles of bobbin mounting without failure of the bobbin top holder.
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The bobbin holder of the invention is convenient to use and
advantageously improves the efficiency of the preferred braider apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention will be described herein
with reference to the drawings, wherein:
Fig. 1 is a partial perspective view of a braider apparatus for
braiding fine denier yarns constructed in accordance with the preferred
embodiment of the invention;
Fig. 2 is a partial perspective view with parts separated for
convenience of illustration, showing the carrier housing assembly and
bobbin top holder contructed in accordance with the preferred embodiment
of the invention;
Fig. 3 is an elevational view, partially in cross-section, of
the preferred yarn tension control system of the invention;
Fig. 4 is a partial cross-sectional view taken along lines 4-4
of Fig. 1 illustrating a yarn carrier engaged with a carrier plate and
the main support plate;
Fig. 5 is a perspective view of the preferred bobbin; , `-
Fig. 6 is an elevation view of the bobbin, carrier, and bobbin
top holder assembly constructed in accordance with the preferred
embodiment of the invention, illustrating the bobbin in cross-section;
Fig. 7 is a top view of the bobbin top holder constructed in
accordance with the preferred embodiment of the invention;
Fig. 8 is a cross-sectional view of the bobbin top holder taXen
along lines 8-8 of Fig. 7;
Fig. 9 is an elevation view of the spindle tip constructed in
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accordance with the preferred embodiment of the invention;
Fig. 10 is an elevational view of the bobbin top holder mounting
base constructed in accordance with the preferred embodiment of the
invention; and
Fig. 11 is a top plan view of the bobbin top holder mounting
base of Fig. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring initially to Fig. 1, there is illustrated an apparatus
~or braidin~ sutures constructed according to the present invention.
The apparatus 10 is supported on frame 12 which includes a horizontal
support plate 14. Electrically powered motor 16 is arranged to drive the
apparatus as will be described. In operation, motor l~j drives carrier
plates 18 around main carrier support plate 20 along a predetermined
path. A plurality of yarn bobbin carriers 22, only one of which is
illustrated in Fig. 1 for simplicity, are mounted to carrier plates 18
and dispense yarns from yarn bobbins 24 (see Fig. 6) as the bobbins and
carriers follow a predetermined path around the main carrier support
plate. The apparatus illustrated in Fig. 1 is designed to drive the
bobbin carriers in undulating paths in opposite directions around the
main carrier plate in a known manner. However, alternate carrier path
configurations also are contemplated, such as a spiral pattern in which
all bobbin carriers move in the same direction around the main carrier
plate. Spiral braiders, per se, are also known.
As illustrated in Fig. 1, yarns 3 dispensed Erom each bobbin
carrier station are led to a braiding zone and formed into an elongated
braided suture product. Tension on the braided suture product is
controlled by driven tension rollers 26, 28 and take-up roller 30.
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Optionally, a core yarn bobbin 29 is mounted beneath support plate 14.
The optional core yarn 31 maintained under tension is led through a core
yarn tension detector 33 and a hollow tube 32 to the braiding zone, such
that sheath yarns from the yarn carriers mounted on main carrier plate 20
are braided about the core yarn.
Referring now to Figs. 2-4 and 6 the yarn carrier system and
yarn tensioning system is illustrated. Referring initially to Fig. 4,
there is shown a cross-sectional view of the base of a yarn carrier 22
mounted to carrier support plate 18. Carrier 22 has downwardly extending
connector shoes 38, 40 which extend into guide channels in the main
carrier support plate 20. The connector shoes traverse the respective
guide channels as the yarn carrier is transferred between the respective
carrier support plates 18. In an alternative contemplated arrangement
the carriers are transported around the main carrier support plate in a
spiral pattern.
As shown in Figs. 2-3, yarn bobbin carrier 22 has a carrier
housing 42 with a spindle 44 extending vertically there:Erom to receivably
engage bobbin 24. A yarn guide support 46 also extends from carrier
ho~lsing 42 in a direction substantially parallel to spindle 44, and is
shown in Fig. 2 as a pair of rods 46A and 46B. A yarn dispensing guide
eyelet 48, preferably made rom a ceramic material, is fixed to one rod.
A compansator eyelet 50, also preferably made from a ceramic material,
slidably engages the other rod. Compensator eyelet 50 ls connected via a
con~pensator rod 52 to a compensator arm 54 for controlling the dispensing
of yarn in response to tension exerted by the yarn on compensator arm 54
via compensator rod 52 and eyelet 50. Compensator arm 54 pivots about
pivot pin 56 on carrier 22, as shown in Fig. 3. End portion 58 of
compensator arm 54 is connected to compensator rod 52 while the opposite
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end portion 60 of pivot arm 54 engages pin 62 which is biased upwardly by
a light coil spring 64. Pin 62 is disposed in and moves upwardly and
downwardly in slot 63. Pin 62 is connected to pawl 66 arranged to float
into and out of radial slots 68 on the 1ower surface of yarn bobbin 24.
Pin 70 moves upwardly and downwardly in slot 72 in carrier housing 42
while traversing the moving arcuate slot 74 in compensator arm 54. Pin
62 is biased upwardly by spring 64 and, in turn, biases end portion 60
upward, pivotally rotating compensator arm 54 to urge arm end 58, rod 52
and compensator eyelet 50 downwardly. The upper ends of rods 46A and 46B
are seated in and support a top holder support 76. Top holder support 76
has two substantially parallel vertical apertures 78, 80 configured to
receive rods 46A, 46B, as by frictional engagement or by an adhesive
disposed therebetween (see Fig. 11). Top holder support 76 includes a
substantially horizontal yarn guide section 82 extending from support 76
and having a ceramic yarn guide eyelet 8~ for guiding yarn dispensed from
the bobbin toward the braiding zone. Top holder support 76 also has a
pair of hinge pins 86, 88 (see Fig. 11) extending longitudinally
therefrom in a direction substantially perpendicular to the spindle.
Bobbin top holder 90 has a pair of hinge pin engaging legs 92, 94. Each
leg has an enlarged hinge pin receiving section 96 having a hinge pin
aperture 98 configured and dimensioned to receive hinge pins 86, 88. In
this manner bobbin top holder 90 is mounted to top holder support 76 and
is hingedly rotatable about the axis of hinge pins 86, 88.
Bobbin top holder 90 has a substantially planar section lO0
extending from legs 92, 94 and a pair of spindle gripping legs 102, 104
defining therebetween a slot 106 and a spindle engaging recess 108. Fig.
7 is a top plan view of bobbin holder 90. Referring now to Fi~. 8, a
cross-sectional view of the bobbin holder taken along lines 8-8 of Fig.
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7, it can be seen that spindle engaging recess 108 is configured with an
outwardly tapered entrance wall 110, a substantially cylindrical barrel
section 112, an inwardly projecting radiused section 114, and an
outwardly tapered exit wall section 116. Preferably, entrance wall 110
defines an angle of about 10 to 20 relative to the axis of recess
108, and exit walls 116 define an included angle on the order of about
90. The spindle engaging recess is symetrical about its vertical
axis, except for slot region 106, and is identically configured in both
legs 102, 104. As shown in Fig. 8, spindle engaging recess 108 is
disposed in a region 140 of legs 102, 104 of grea~er thickness than the
remaining portions of the legs in order to provide structural support
surrounding the spindle engaging recess.
Referring again to Fig. 2, spindle 44 is provided with a bobbin
holder engaging tip 118 configured to be disposed in spindle engaging
recess 108 to secure bobbin top holder 90 to spindle 44 and, hence,
bobbin 24 on spindle 44 (see Fig. 6). The preferred spindle tip
configuration for engaging recess 108 is illustrated in Fig. 9. As shown
in Fig. 9, spindle tip 118 has a spindle engaging shank 120 connected to
a spindle tip body 122. Spindle tip body 122 has a substantially
cylindrical proximal base 124, a spindle tip recess 126 defined by a pair
of inclined walls 128, 130, and a substantially frusto-c~nical distal tip
section 132. Distal tip section 132 and recess 126 may be ~oined by a
s~bstantially cylindrical transition section 134. Shank 120 is
configured to be received in a hollow recess in spindle 44 to fixedly
mount spindle tip 118 to spindle 44. Fixed mountLng of tip 118 to
spindle 44 may be accomplished by friction fit of shimk 120 in the
spindle recess, by providing an adhesive or combination of adhesive and
friction between the shank and recess, or most preferably by providing
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mutually engageable threads on the shank and within the recess. In the
preferred embodi~ent wherein threads 131 are provided, a slot 136 may be
provided in distal tip 132 for engaging a tool, such as a screwdriver.
Inclined walls 128, 130 preferably define an interior angle on the order
of about 90, and the walls of frusto-conical distal tip 132 preferably
define an angle of about 20O relative to the tip axis. As in the case
of spindle engaging recess 108, spindle tip 118 preferably is symetrical
about the axis thereof.
Referring now to Fig. 5, the bobbin 24 preferred for use with
the unique yarn dispensing system according to the present invention is
shown. Bobbin 24 is integrally constructed of a li~htweight material
s~lch as molded nylon or other plastic material. The bobbin includes a
hollow cylindrical opening 140 configured to slidably receive spindle 44
with bobbin 24 being rotatable about the spindle (see Figs. 2 and 6).
In use, bobbin 24 is mounted onto spindle 44 with the bobbin top
holder 90 in the open or unlocked position, as shown in Fig. 2. When
mounted, radial slots 68 on bobbin 24 engage pawl 66 on carrier housing
42. Braiding yarn 3 is led from bobbin 24 through dispensing eyelet 48,
compensator eyelet S0 and guide eyelet 84 and upward to the braiding zone
(also see Fig. 6). As will be explained in greater detail below, bobbin
top holder 90 is rotated and locked into the position shown in Fig. 6 to
hold bobbin 24 on spindle 44 during braiding.
During operation of the braiding apparatus, yarn is drawn
upwardly by the braiding system. Yarn is dispensed from bobbin 24 until
~he tension on the yarn exceeds a predetermined value and draws
compensator eyelet 50, rod 52 and compensator arm end portion 58 upward
(see Figs. 2-3). The opposite end 60 of arm 54 depresses pin 62 against
spring 64, causing pawl 66 to withdraw from slot 68 in the bobbin 24.
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Removal of pawl 66 from slot 68 permits bobbin 24 to rotate about spindle
44 to dispense more yarn. As further yarn is dispensed, the tension in
the yarn is reduced below a predetermined value until the force of spring
64 again urges arm end portion 60 upward, rotatably pivoting arm 54 so
that end portion 5~, rod 52 and compensator eyelet 50 move downward.
Pawl 66 simultaneously re-enters radial slot 68 in bobbin 24 to prevent
further rotation of the bobbin until the cycle is repeated.
Preferably, fine denier multifilament yarns in the range of
about 0.2 to 6.0 denier are dispensed from bobbin 24, with the tension of
the yarn dispensed from bobbin 24 closely controlled within a precise
range. The tension of the yarns is controlled within a precise range,
particularly by selecting a spring 64 which is within a predetermined
range of spring rates. Prior art braiders utilized a spring 64 of
significantly greater spring rate than is contemplated herein due to the
fact that braiding was accomplished with heavier braiding materials. In
addition, in prior art braiders pin 70 was also arranged to be biased
downwardly by a spring positioned centrally within spindle shaft 44. In
the present apparatus the central spring has been eliminated and spring
64 has been selected to have a reduced spring rate in the range of from
about 0.6 to 0.7 pounds per inch. The standard spring on such braiders
having a much higher spring rate on the order of about 0.9 to about 1.0
pounds per inch. Reducing the spring rate reduces the tension force on
the yarn necessary to cause pivot arm 54 to rotate and withdraw pawl 66
from slot 68, thereby permitting the bobbin to rotate and pay out
additional yarn. The reduced spring rate accommodates the relatively
lower tensile strength associated with yarns of aforementioned preferred
denier range suitable for producing braided sutures. The production of
such sutures is thus carefully and precisely controlled to accommodate
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the fine character, not only of the finished braided suture, but
particularly of the yarn components thereof.
As previously noted, bobbin 24 is constructed of a lightweight
moldable material such as nylon and defines a central axial opening 140
extending the length of the bobbin to receive the carrilsr housing spindle
(see Figs. 2 and 6). With bobbin holder 90 disengaged from spindle 44
and rotated away from the spindle, such as in the subslantially vertical
bobbin holder position shown in Fig. 2, the bobbin may be mounted over
the spindle with spindle 44 received within opening 140. Referring now
to Figs. 2 and 6-9, after bobbin 24 is mounted over spindle 44 wi~h pawl
66 seated in a bobbin slot 68, bobbin holder 90 is rotated about hinge
pins 86, 88 until inwardly projecting radiused section 114 on each bobbin
holder leg 102, 104 contact the angled surface of frusto-conical distal
tip section 132. Preferably, contact between section 114 and tip section
132 occurs slightly before holder 90 reaches a position perpendicular to
the axis of spindle 44. Exerting force on holder 90 to urge holder 90
against spindle tip 118 causes holder legs 102, 104 to be spread apart
slightly by the camming action of frusto-conical tip 132 against section
114. Legs 102, 104 are spread apart until radiused section 114 is
mounted over the distal tip section 132 and thereafter resiliently return
to their rest position and become disposed within recess 126, as shown in
Fig. 6. Thus, maximum spreading of legs 102, 104 occu:rs when radiused
section 114 is disposed at cylindrical section 134 having substantially
the same diameter as spindle tip base 124. In the locked or hold down
position illustrated in Fig. 6, inwardly extending radiused section 114
is disposed in recess 126 with outwardly extending exit wall 116
juxtaposed to distal recess wall 130 and the lower radiused section 114
disposed adjacent proximal inclined recess wall 128. Cylindrical section
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112 is disposed around spindle tip base 124. As shown in Fig. 6, the
maximum diameter of tip 118 approximates the diame~er of spindle 44 to
facilitate mounting and removal of the bobbin onto and from the spindle.
Referring again to Fig. 6, with bobbin top holder 90 in the
locked or hold down position engaging spindle tip 118 the relatively
thick section 140 is disposed within the open area 142 on bobbin 24
radially within radial segments 138, with the remaining portions of legs
102, 104 disposed above and away from radial segments 138. In the event
bobbin 24 rides up slightly, as may occur during yarn dispensing, thick
section 140 abuts the flat central region on the end of the bobbin to
prevent further upward movement of the bobbin. However, at no time does
bobbin holder 90 engage radial segments 138 or otherwise obstruct
rotational movement of the bobbin about spindle 44.
In order to remove a bobbin from the apparatus, i.e. after all
the desired yarn has been dispensed from the bobbin during braiding,
upward force is exerted on bobbin top holder 90, such as at the distal
areas of legs 102, 104. This causes inclined wall 130 on tip 118 to cam
against exit wall 116 of recess 126 and spread apart legs 102, 104,
thereby causing inwardly projecting radiused section 114 to spread apart
and become disengaged from recess 126. As radiused section 114 is
removed from spindle 118 over frusto-conical distal tip 132, bobbin top
holder legs 102, 104 resiliently return to their rest position wherein
the separation distance of radiused sections 114 on each leg approximates
the minimum diameter of spindle tip 118 within recess 126. At this point
bobbin top holder 90 may be further rotated about hinge pins 86, 88 until
holder 90 is rotated to a position such as shown in Fig. 2 out of the way
to permit removal of the empty bobb3.n and/or placement of a new bobbin
loaded with yarn to be dispensed for braiding.
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The bobbin carrier and spindle may be made of metal, such as
stainless steel, with top holder support rods 46A, 46B made from the same
or different metal, e.g. aluminum, or a rigid plastic material. Ceramic
eyelet 48 may be mounted to rod 46B by wrapping a metal wire around both
the eyelet and the rod to fix the eyelet to a central region of the rod.
Ceramic eyelet 50 may be mounted to rod 46A by similarly wrapping a metal
wire around the eyelet and around rod 46A, to permit slidable movement of
the wire relative to rod 46A. Preferably, compensator rod 52 is
integrally formed of the same wire which connects ceramic eyelet 50 to
rod 46A. This may be accomplished by wrapping the wire around eyelet 50,
looping the wire around rod 46A, and extending the wire to engage
compensator arm end section 58, as illustrated in Figs. 2-3. Top holder
support 76 preferably is made of a rigid plastic material, such as
nylon. Top holder 90 is made of a plastic material which is sufficiently
flexible and resilient to deform and permit legs 102, 104 to repeatedly
be spread apart and mounted over spindle tip 118 through multiple cycles,
such as an elastomeric nylon material. Advantageously, both top holder
support 76 and bobbin top holder 90 may be injection molded at
relatively modest cost. Spindle tip 118 should be made of a rigid metal
material, such as a zinc coated steel.
As will be appreciated, the bobbin top holder of the present
invention facilitates quick and easy placement and removal of a bobbin
relative to the spindle and bobbin carrier. Advantageously, the top
holder of the invention does not require any pinching or gripping action
by the user, such as to unscrew a prior bobbin holder, thereby minimizing
the effort which must be exerted by the user to engage or release the
bobbin top holder and reducing the time required to change bobbins on the
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carrier. These reductions in exerted energy and time contribute to
increased efficiency in the braiding operation, which efficiencies become
considerable in operating a large number of braiding apparatus each
having multiple yarn carriers.
It will be readily appreciated that the features of the present
invention as described hereinabove make it possible to produce a fine
denier braid capable of application as a suture for surgery. More
particularly, the braiding apparatus is well suited for high speed
production of consistently high quality final braided suture products
having an overall suture denier ranging from as low as about 50 denier to
as large as about 4,000 denier. Core yarns will have a preferred denier
of from as low as about 20 denier to as high as about 2,400 denier, and
sheath yarns will have a denier of from as low as about 0.2 denier to as
high as about 6.0 denier.
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