A BOBBIN COVER PLATE USED IN TWISTER
TECHNICAL FIELD
The present invention is related to a bobbin cover plate used in
twister. More particularly, the present invention is related to a bobbin
cover plate used in twister, wherein twisting 2 strings of polyester yarns
together used for rubber reinforcing tire cord, for solving several problems
caused by unwinding inferiority of yarn feeding bobbin(B) and improving
ratio of full drum.
BACKGROUND ART
The tire cord for rubber reinforcement is weaved with 2 strings of
equally twisted yarn of high modules low shrinkage polyester as its warp
and covering yarn of high modules low shrinkage polyester covered by
cotton yarn as its weft. Saurer Twister of Allma Co. has been primarily
used for the preparation of the said warp of tire cord.
As for the said former twister, as shown in Figure 1 , twist 1 string of
polyester yarn fed from yarn feeding bobbin(A) and another 1 string of
polyester yarn fed from yarn feeding bobbin(B) standing upright position to
the said bobbin(A) in cord regulator(4), then winding at winding bobbin(C)
by passing through capstan(5). The 1 string of polyester yarn fed from
the bobbin(B) standing upright reaches to cord regulator(4) passing
through inner yarn tensioner(3) by guide roller(2).
There is high possibility for yarn in bobbin(B) to slip down under
bobbin during unwinding (hereinafter called "Slip Phenomenon") since the
yarn feeding bobbin(B) is standing upright. Also, in the process of
preparing yarn feeding bobbin(B), it is obliged to have minor winding
tension difference during the winding yarn in bobbin(B), and there could
be fine hairs on yarn winded in bobbin(B).
In the former twister, lots of unwinding inferiority happen during the
unwinding of yarn from yarn feeding bobbin(B) to guide roller(2) due to the
said reasons such as Slip Phenomenon, winding tension difference, and fine
hairs in yarn.
Thus, there are several problems in the former twister that
over-feeding of yarn or jumping phenomenon of yarn to upward
(hereinafter called "jumping phenomenon") due to the said unwinding
inferiority.
As a result, the yarn is frequently squeezed and chewed between
guide roller(hereinafter called "chewing phenomenon"), or winded around
inner yarn tensioner(3). In this case, the twister stops automatically
since higher tension(±10%) comparing to the setting value is loaded to the
self adjusting sensor. Accordingly, the ratio of full drum of the former
twister is in low level at 90—92% in general.
The more rotation speed(rpm) of twister, the more happening of
these serious phenomena. Because of these reasons, it is serious problem
for the former twister to drop down the ratio of full drum remarkably if the
twister is operated over than 7,500rpm.
The object of present invention is to provide a bobbin cover plate(l)
which can resolve the aforesaid problems caused by unwinding inferiority
during the process of high speed unwinding of yarn from yarn feeding
bobbin(B). In addition, the object of present invention is to improve the
productivity(rotation speed) and ratio of full drum of the twister.
DISCLOSURE OF INVENTION
The present invention is related to a bobbin cover plate used in
twister. More particularly, the present invention is related to a bobbin
cover plate used in twister, wherein twisting 2 strings of polyester yarns
used for rubber reinforcing tire cord, for solving several problems caused
by unwinding inferiority of yarn feeding bobbin(B) and improving ratio of
full drum.
The present invention is to provide a bobbin cover plated ) which
can resolve the problems caused by unwinding inferiority during the
process of high speed unwinding of yarn from yarn feeding bobbin(B).
In the present invention, particularly, bobbin cover plated ) used in
twister is installed in right upward angle to the yarn feeding bobbin(B) as
shown in Figure 2. From this installation, it is possible to prevent the
chewing phenomenon, or winded around inner yarn tensioner(3) by
precluding the yarn over-feeding even in a high speed twisting.
The bobbin cover plate, shaped in circular plate, used in twister
characterized in that • a yarn guide grooved a) which guides the yarn in
yarn feeding bobbin(B) to upper direction of the bobbin cover plated ) is
installed in the center part of the circular plate, a yarn guide supporter(lb)
having punched yarn guided c) which feed the yarn in the center of guide
roller(2) is installed in lower part of the circular plate which is located at
right front position of guide roller(2) during operation, and a fixed part(ld)
which can fix the bobbin cover plate(l) to the body of guide roller(2) is
installed in upper side of the circular plate.
Detail illustration on the present invention is followed hereinafter.
First of all, the bobbin cover plate used in twister of the present
invention is round circular plate as shown in Figure 3. The favorable
diameter of the circular bobbin cover plate(l) is 85~95% of the diameter of
yarn feeding bobbin(B) in full-drum condition. If the diameter of the
bobbin cover plate(l) is too large, the operation shall be inconvenient.
If it is too small, it is not possible to effectively protect the jumping
phenomenon and chewing phenomenon caused by unwinding inferiority.
A yarn guide grooved a) which guides the yarn in yarn feeding
bobbin(B) to upper direction of bobbin cover plate(l) is installed in the
center part of the circular plate. In the rim of the said yarn guide
grooved a), ceramic protection is prepared in order to prevent any fine
hairs in the yarn.
In the meantime, a yarn guide supporter(lb) having punched yarn
guide(lc) which feed the yarn in the center of guide roller(2) is installed in
lower part of the circular plate which is located at right front position of
guide roller(2) during operation. The said yarn guide supporter(lb)
shaped ^- as shown in Figure 3. The angle of θ in Figure 3 is 50-70°.
More preferably, the angle of θ is 60°. Occasionally, the yarn guide
supporterdb) may have shape.
If the angle of θ is not within the aforesaid range, the yarn fed from
yarn feeding bobbin(B) may not be fed precisely to the exact center of
guide roller(2). The height(center basis) of yarn guide(lc) installed in
the yarn guide supporter(lb) should be set up as same as that of guide
roller(2). If the height of yarn guide(lc) is set up wrong, fine hairs may
come into exist due to the touch of yarn with the rim of yarn guide( lc).
In the meantime, a fixed part(ld) which can fix the bobbin cover
plate(l) to the body of guide roller(2) is installed in upper side of the
circular plate. By bolting the hole of said fixed part(ld), fix the bobbin
cover plate(l) to the lower part of guide roller body.
For the material of bobbin cover plate(l) in the present invention,
plastic such as acryl may be used, considering impact strength, in
particular, polycarbonate is favorable, and anti-static treated
polycarbonate is more favorable. Additionally, it is more favorable to
prepare bobbin cover plated ) with transparent plastic resin that the
operation status of yarn could be observed during twisting process. It
is more favorable to treat the rim of the circular plate roundly for the
prevention of any damage(fine hairs etc.) to yarn.
From figure 2, detail illustration on the twisting process for rubber
reinforcing yarn by using the bobbin cover plated ) of the present invention
is followed hereinafter.
The bobbin cover plated ) of the present invention is fixed at the
lower part of guide roller(2) so as to the bobbin cover plate locates at the
right upward angle to yarn feeding bobbin(B).
One string of yarn fed from yarn feeding bobbin(A) installed in
certain inclination angle, is feed to cord regulator(4) through magnetic
brake, and another one string of yarn fed from yarn feeding bobbin(B)
standing upright is feed to cord regulator(4) through the bobbin cover
plate(l) of the present invention.
In this case, the yarn fed from yarn feeding bobbin(B) standing
upright comes up to the upper part of bobbin cover plated ) through yarn
guide grooved a) of the present invention, and is feed to the center part of
guide roller(2) through the hole of yarn guided c) installed in yarn guide
supporterdb).
The said guide roller(2) guide yarn before the yarn comes up to
inner yarn tensioner(3), and provides certain tension with yarn. In
addition, the said inner yarn tensioner(3) substantially provides yarn come
up from yarn feeding bobbin(B) with tension before it reaches to cord
regulator(4).
It is favorable to provide yarn with 1, 340— 1 , 350g/d of tension in the
said inner yarn tensioner(3). If the yarn is twisted without having
proper tension, the twisting shall be unequal. When the twist gets
unequal, the length difference of yarn(hereinafter called "LD value"),
measuring each of the length of yarn after untwisting the twisted yarn, gets
bigger and the property of tire cord gets deteriorated. The lower LD
value the better it is, but up to 5mm of LD value is permitted.
2 strings of yarn fed to cord regulator(4) respectively are twisted
together in cord regulator. The cord regulator(4) aggregate and twist
the fed 2 strings of yarn by its self-rotation movement.
In case the bobbin cover plate of the present invention is installed, it
is possible to get high ratio of full drum even more than 9,000rpm of cord
regulator(4). Twisted yarn from cord regulator(4) is winded at
winding bobbin(C) passing through capstan(5) and etc.
The circular shaped bobbin cover plated ) of the present invention
protects the over-feeding of yarn from yarn feeding bobbin(B) to guide
roller(2) and jumping phenomenon of yarn caused by unwinding inferiority.
As a result, it is possible to prevent chewing phenomenon of yarn in guide
roller(2) and unequal tanglement of yarn in inner yarn tensioner(3).
Accordingly, when the circular shaped bobbin cover plate(l) of the
present invention is used, the ratio of full drum of the twister shall be
improved over than 99% since the jumping phenomenon and chewing
phenomenon caused by unwinding inferiority of yarn feeding bobbin(B)
could be prevented.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 is a rough-drawing of former twisting process.
Figure 2 is a rough-drawing of twisting process of the present
invention.
Figure 3 is a plane drawing of bobbin cover plate(No. 1 in Figure 1)
of the present invention
Figure 4 is an enlarged-drawing of inner yarn tensioner(3) in Figure
1.
^ Legend for the main part of Figures
A, B : Yarn feeding bobbin C • Winding bobbin
1 : Bobbin cover plate 2 : Guide roller
3 '■ Iinner yarn tensionerGnternal tension controller of yarn)
4 : Cord regulator(twist providing device) 5 • Capstan
la • Yarn guide groove lb • Yarn guide supporter
lc • Yarn guide Id • Fixed part
BEST MODE FOR CARRYING OUT THE INVENTION
More concretely, the present invention shall be examined through
following examples and comparative examples. The present invention,
however, is not limited only to following experimental examples.
Example 1
Twist 2 strings of 1,500 denier polyester yarn at 9,000rpm of
twisting speed and l,340g/d of twisting tension with Saurer Twister of
Allma Co. (see Figure 2) wherein the bobbin cover plate(l) of the present
invention is installed at right upward angle to yarn feeding bobbin(B) as
shown in Figure 3. The said bobbin cover plate(l) is made of acryl resin
and the diameter is 200mm. Also, the θ angle of yarn guide
supporter(lb) is 65°, and the diameter of yarn guide groove (la) is 10mm.
The turn number of yarn in inner yarn tensioner(3) is set up at 5 times.
Table 2 is the experiment result on ratio of full drum, LD value and waste
ratio.
Example 2 - Example 3
Except the change of specification and material of bobbin cover
plate(l), twisting speed, and twisting tension as shown in Table 1 , twist 2
strings of 1,500 denier polyester yarn as same process and condition of
example 1. Table 2 is the experiment result on ratio of full drum, LD
value and waste ratio.
[Table 1 ] Preparing condition
Comparative Example 1
Twist 2 strings of 1,500 denier polyester yarn at 6,500rpm of
twisting speed and l,340g/d of twisting tension with usual Saurer Twister
of Allma Co. (see Figure 1) wherein the bobbin cover plate(l) of the present
invention is NOT installed. Table 2 is the experiment result on ratio of
full drum, LD value and waste ratio.
[Table 2] Experiment Result
INDUSTRIAL APPLICABILITY
The present invention prevents the over-feeding and jumping
phenomenon of yarn caused by unwinding inferiority of yarn feeding
bobbin(B). As a result, it is possible to improve the twister's ratio of
full drum over than 99% since the chewing phenomenon or rolling
phenomenon is remarkably decreased even the rotation speed of twister is
elevated. In addition, the productivity is improved since the rotation
speed of twister could be elevated until lO.OOOrpm.