SPINNING MACHINE
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a spinning machine.
2. Description of the Related Art
Conventionally, there is known a spinning unit adapted to
draft a fiber bundle and twist the drafted fiber bundle to produce
a spun yarn (see e.g., Japanese Unexamined Patent Publication No.
2011-99192) . The spinning unit includes a winding section adapted
to wind a spun yarn to form a package. The winding section includes
a driving roller adapted to rotate the package in a forward direction,
and a cradle adapted to rotatably support the package.
Conventionally, there is known a spinning machine including
a plurality of spinning units (see e.g., Japanese Unexamined Patent
Publication No. 2011-84854). The spinning machine includes an
operation cart adapted to travel to one of the spinning units and
perform a yarn joining operation when a continuation of the spun
yarn is disconnected in such spinning unit. The operation cart
includes a braking section adapted to brake rotation of the package,
a reverse-rotation roller adapted to rotate the package in an
unwinding direction, which is an opposite direction of the winding
direction, a guiding section adapted to catch and guide the spun
yarn, and a yarn joining section adapted to join yarn ends of the
spun yarn.
The spinning unit swings the cradle when the continuation of
the spun yarn is disconnected, and separates the package from the
driving roller. After stopping the rotation of the package by the
braking section, the operation cart makes the reverse-rotation
roller to contact with the package and rotates the package in the
unwinding direction (hereinafter, simply referred to as "reverse
rotation"). The operation cart catches the spun yarn and guides
the spun yarn to a predetermined position by the guiding section,
and joins the yarn ends of the spun yarn by the yarn joining section.
Thereafter, the spinning unit swings the cradle again, and makes
the package to contact with the driving roller. The spinning unit
can resume formation of the package through such series of
processes.
BRIEF SUMMARY OF THE INVENTION
The inventor recognized that, in the prior art, while
separating the reverse-rotation roller from the package, the
package may reversely rotate unintendedly accompanying movement
of the reverse-rotation roller. When the reverse-rotation roller
is separated from the package immediately after the spun yarn is
joined by the yarn joining section, the package may reversely rotate
unintendedly and the spun yarn may slacken.
An object of the present invention is to provide a spinning
machine in which a spun yarn does not slacken in a series of processes
after formation of a package is interrupted and until the formation
of the package is resumed.
A spinning machine comprises a plurality of spinning units,
each spinning unit being adapted to wind a spun yarn to form a package,
a driving roller adapted to make contact with the package to rotate
the package in a winding direction, a cradle adapted to move the
package to a contacting position and a receded position with respect
to the driving roller, a reverse-rotation roller adapted to make
contact with the package to rotate the package in an unwinding
direction that is in an opposite direction of the winding direction,
a driving section adapted to make the package and the
reverse-rotation roller to contact with or separated from one
another, and a control section adapted to control the driving
section to separate the reverse-rotation roller and the package
immediately before the package reaches the contacting position with
respect to the driving roller by the package being moved by the
cradle.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view illustrating an overall structure of a
spinning machine;
FIG. 2 is a view illustrating a structure of a spinning unit
and an operation cart;
FIG. 3 is a view illustrating a process of stopping rotation
of a package;
FIG. 4 is a view illustrating a process of reversely rotating
the package;
FIG. 5 is a view illustrating a process of catching a
disconnected spun yarn;
FIG. 6 is a view illustrating a process of guiding the
disconnected spun yarn;
FIG. 7 is a view illustrating a process of resuming formation
of the package;
FIG. 8 is a view illustrating a structure of a driving section;
FIG. 9A is a view illustrating a state in which a
reverse-rotation roller is making contact with the package;
FIG. 9B is a view illustrating a state in which the
reverse-rotation roller is separated from the package; and
FIG. 10 is a view illustrating a structure of a spinning
section.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
First, with reference to FIG. 1, an overall structure of a
spinning machine 100 will be briefly described. In FIG. 1, black
arrows indicate a travelling direction of an operation cart 20,
and white arrows indicate a travelling direction of a doffing cart
30.
The spinning machine 100 includes a plurality of spinning
units 10. The spinning machine 100 includes the operation cart 20,
the doffing cart 30, and a control section 40.
The spinning unit 10 is adapted to draft a fiber bundle F and
twist the drafted fiber bundle F to produce a spun yarn Y. The
spinning unit 10 can form a package P by winding the spun yarn Y.
A detailed structure of the spinning unit 10 will be described later.
The operation cart 20 can travel along a rail Rl extending
in a direction in which the spinning units 10 are arranged. When
a continuation of the spun yarn Y is disconnected in one of the
spinning units 10, the operation cart 20 travels to the relevant
spinning unit 10 and performs a yarn joining operation. A detailed
structure of the operation cart 20 will be described later.
The doffing cart 30 can travel along a rail R2 extending in
a direction in which the spinning units 10 are arranged. When the
package P is fully wound in one of the spinning units 10, the doffing
cart 30 can travel to the relevant spinning unit 10 and collect
the package P. The doffing cart 30 can set a new bobbin B to the
spinning unit 10. The doffing cart 30 may perform only an operation
of collecting the fully-wound package P. If the collecting of the
package P and the setting of the new bobbin B are manually performed
by an operator, the doffing cart 30 may be omitted.
The control section 40 can control each spinning unit 10, the
operation cart 20, and the like. For example, when the continuation
of the spun yarn Y is disconnected in one of the spinning units
10, the control section 40 controls the relevant spinning unit 10
to interrupt the formation of the package P. After controlling the
operation cart 20 to perform the yarn joining operation, the control
section 40 controls the spinning unit 10 to resume the formation
of the package P.
Next, with reference to FIG. 2, the structure of the spinning
unit 10 and the operation cart 20 will be described. In FIG. 2,
black arrows indicate a feeding direction of the fiber bundle F
and the spun yarn Y, and a white arrow indicates a rotating direction
of the package P.
First, the spinning unit 10 will be described. The spinning
unit 10 includes a sliver supplying section 1, a drafting section
2, a spinning section 3, a defect detecting section 4, a tension
stabilizing section 5, and a winding section 6 along the feeding
direction of the fiber bundle F and the spun yarn Y.
The sliver supplying section 1 is adapted to supply the fiber
bundle F to the drafting section 2. The sliver supplying section
1 includes a sliver case 11 and a sliver guide (not illustrated).
The fiber bundle F accumulated in the sliver case 11 is guided by
the sliver guide to the drafting section 2.
The drafting section 2 drafts the fiber bundle F to make a
thickness of the fiber bundle F uniform. The drafting section 2
includes four sets of draft roller pairs 2a, 2b, 2c, and 2d, i.e.,
the back roller pair 2a, the third roller pair 2b, the middle roller
pair 2c, and the front roller pair 2d, along the feeding direction
of the fiber bundle F. Each of the draft roller pairs 2a, 2b, 2c,
and 2d includes a bottom roller, which is rotated via a power
mechanism (not illustrated), and a top roller, which makes contact
with the bottom roller and rotates accompanying rotation of the
bottom roller. An apron band is wound around each of the bottom
roller and the top roller of the middle roller pair 2c. Since the
bottom rollers and the top rollers rotate while sandwiching the
fiber bundle F, the draft roller pairs 2a, 2b, 2c, and 2d can feed
the fiber bundle F. The drafting section 2 can draft the fiber
bundle F by a difference in a feeding speed of the draft roller
pairs 2a, 2b, 2c, and 2d adjacent to one another.
The spinning section 3 twists the drafted fiber bundle F to
produce the spun yarn Y. The spinning section 3 is arranged
downstream of the drafting section 2 in the travelling direction
of the spun yarn Y. The spinning section 3 can produce the spun
yarn Y from the appropriately drafted fiber bundle F. A structure
of the spinning section 3 will be described later.
The defect detecting section 4 detects a defective part of
the produced spun yarn Y. Specifically, the defect detecting
section 4 irradiates the spun yarn Y with a light emitting diode
(not illustrated) as a light source, and detects a reflected light
quantity from the spun yarn Y. The defect detecting section 4 is
connected to a control section 40 via an analyzer (not illustrated) .
The control section 40 can determine presence or absence of the
defective part in accordance with a detection signal from the defect
detecting section 4. A cutter 41 capable of cutting the spun yarn
Y is provided in proximity to the defect detecting section 4. In
addition to abnormality in which a portion of the spun yarn Y is
too thick (thick yarn) or too thin (thin yarn) , the defective part
of the spun yarn Y includes foreign substances contained in the
spun yarn Y. Instead of an optical sensor according to the present
embodiment, a capacitance sensor or the like can be adopted as the
defect detecting section 4.
The tension stabilizing section 5 is adapted to appropriately
maintain and stabilize a tension applied to the spun yarn Y. The
tension stabilizing section 5 includes an unwinding member 51 and
a roller 52. The unwinding member 51 rotates with the roller 52
when the tension applied to the spun yarn Y is low, and winds the
spun yarn Y around the roller 52. The unwinding member 51 rotates
independently from the roller 52 when the tension applied to the
spun yarn Y is high, and unwinds the spun yarn Y wound around the
roller 52. The tension stabilizing section 5 can appropriately
maintain and stabilize the tension applied to the spun yarn Y. The
roller 52 is rotatably driven by a motor (not illustrated).
The winding section 6 is adapted to form the package P by
winding the spun yarn Y. The winding section 6 includes a driving
roller 61 and a cradle 62. The driving roller 61 is rotatably driven
by a motor (not illustrated) , and rotates a bobbin B rotatably held
by the cradle 62. Accordingly, the winding section 6 can wind the
spun yarn Y to form the package P, while traversing the spun yarn
Y by a traverse device (not illustrated).
Next, the operation cart 20 will be described. The operation
cart 20 includes a braking section 21, a reverse-rotation roller
22, a driving section 23, a guiding section 24, and a yarn joining
section 25.
The braking section 21 is adapted to make contact with the
package P and brake the rotation of the package P (see FIG. 3).
In the present embodiment, the braking section 21 includes a plate
21a adapted to make contact with an outer peripheral surface of
the package P, and an arm 21b adapted to support the plate 21a.
The braking section 21 merely needs to be able to make contact with
the package P and brake the rotation of the package P, and a shape,
a structure, and the like of the braking section 21 are not limited.
The reverse-rotation roller 22 makes contact with the package
P to rotate (reversely rotate) the package P in an unwinding
direction (a direction opposite to the winding direction) (see FIG.
4, FIG. 5, and FIG. 6). Specifically, after the plate 21a of the
braking section 21 separates from the outer peripheral surface of
the package P, the reverse-rotation roller 22 makes contact with
the package P and reversely rotates the package P.
The driving section 23 rotates the reverse-rotation roller
22 (see FIG. 5 and FIG. 6) . In the present embodiment, the driving
section 23 uses an electric motor 23a, to be described later, to
rotate the reverse-rotation roller 22. The driving section 23 can
move the reverse-rotation roller 22 to make contact with or separate
from the package P (see FIG. 4 and FIG. 7). In the present embodiment,
the driving section 23 uses a pneumatic actuator 23d, to be described
later, to move the reverse-rotation roller 22. The driving section
23 is driven in accordance with a control signal from the control
section 40. The control section 40 can control the driving section
23.
The guiding section 24 is adapted to catch the disconnected
spun yarn Y and guide the spun yarn Y to a predetermined position
(see FIG. 5 and FIG. 6) . The guiding section 24 includes a first
guiding portion 24a adapted to catch the spun yarn Y from the package
P and guide the spun yarn Y to a predetermined position, and a second
guiding portion 24b adapted to catch the spun yarn Y spun from the
spinning section 3 and guide the spun yarn Y to a predetermined
position. Operations of the first guiding portion 24a and the
second guiding portion 24b will be described later.
The yarn joining section 25 joins yarn ' ends of the
disconnected spun yarn Y (see FIG. 6) . Specifically, the yarn
joining section 25 joins the yarn end of the spun yarn Y guided
by the first guiding portion 24a and the yarn end of the spun yarn
Y guided by the second guiding portion 24b. The "disconnected spun
yarn Y" is a concept including at least the spun yarn Y cut by the
cutter 41 and the spun yarn Y disconnected when abnormal tension
is applied on the spun yarn Y. In addition to an air splicer device
adapted to join the yarn ends of the spun yarn Y by a whirling airflow,
a mechanical splicer device and the like may be adopted for the
yarn joining section 25.
As described above, since the operation cart 20 includes the
braking section 21, the reverse-rotation roller 22, the driving
section 23, the guiding section 24, and the yarn joining section
25, the structure of each spinning unit 10 can be simplified and
the structure of the spinning machine 100 can be simplified.
Next, with reference to FIG. 3 to FIG. 7, a series of processes
after the spinning unit 10 interrupts the formation of the package
P and until the formation of the package P is resumed will be
described. In FIG. 3 to FIG. 7, black arrows indicate a moving
direction of each member constituting the spinning unit 10 and the
operation cart 20, and a white arrow indicates the rotating
direction of the package P.
When the defect detecting section 4 detects a defective part
of the spun yarn Y, the spinning unit 10 uses the cutter 41 to cut
the spun yarn Y. One end of the disconnected spun yarn Y (the spun
yarn Y located downstream of the cutter 41) is thus wound into the
package P. The other end of the disconnected spun yarn Y (the spun
yarn Y located upstream of the cutter 41) is sucked and held at
a suction port (not illustrated) arranged in proximity to the cutter
41.
Next, the spinning unit 10 swings the cradle 62 to separate
the package P from the driving roller 61 (see the black arrows in
FIG. 3) . The package P thus continues to rotate by an inertia force
(see the white arrow in FIG. 3). The operation cart 20 travels to
the relevant spinning unit 10 immediately after the cutter 41 cuts
the spun yarn Y.
Next, the operation cart 20 uses the braking section 21 to
stop the rotation of the package P. Specifically, the operation
cart 20 swings the arm 21b to make the plate 21a contact with the
outer peripheral surface of the package P (see the black arrows
in FIG. 3). The operation cart 20 thus stops the rotation of the
package P by friction between the package P and the plate 21a.
Next, the operation cart 20 uses the reverse-rotation roller
22 to reversely rotate the package P. The operation cart 20
reversely rotates the package P such that the first guiding portion
24a can catch the spun yarn Y wound around the package P. First,
the operation cart 20 swings the arm 21b to separate the plate 21a
from the outer peripheral surface of the package P (see the black
arrows in FIG. 4) . Thereafter, the operation cart 20 makes the
reverse-rotation roller 22 to contact with the package P to
reversely rotate the package P. Specifically, the operation cart
20 moves the reverse-rotation roller 22 from a receded position,
which is a position located away from the package P, to a contacting
position, which is a position of making contact with the package
P (see the black arrows in FIG. 4). The operation cart 20 then
rotates the reverse-rotation roller 22 to reversely rotate the
package P (see the white arrow in FIG. 4) . The detailed description
of the driving section 23 will be made later.
The control section 40 controls the driving section 23 such
that a contact pressure of the reverse-rotation roller 22 and the
package P becomes substantially constant independent from the outer
diameter of the package P. Even if the outer diameter of the package
P differs, the difference in the contact pressure of the
reverse-rotation roller 22 and the package P can be reduced. Thus,
deformation of the package P and degradation in quality of the spun
yarn Y wound into the package P can be prevented.
Next, the operation cart 20 uses the guiding section 24 to
catch the disconnected spun yarn Y and guide the spun yarn Y to
a predetermined position. Specifically, the first guiding portion
24a is swung downward from a standby position (downstream in the
yarn travelling direction) to catch the spun yarn Y wound around
the package P (see the black arrow in FIG. 5). The first guiding
portion 24a is swung upward while sucking and holding the spun yarn
Y to guide the spun yarn Y to a predetermined position (see the
black arrow in FIG. 6) . The second guiding portion 24b is swung
upward from a standby position (upstream in the yarn travelling
direction) to catch the spun yarn Y spun from the spinning section
3 (see the black arrow in FIG. 5) . The second guiding portion 24b
is swung downward while sucking and holding the spun yarn Y to guide
the spun yarn Y to a predetermined position (see the black arrow
in FIG. 6).
Next, the operation cart 20 joins the yarn end of the spun
yarn Y guided to the predetermined position by the first guiding
portion 24a and the yarn end of the spun yarn Y guided to the
predetermined position by the second guiding portion 24b.
Thereafter, the spinning unit 10 resumes the formation of the
package P. The spinning unit 10 swings the cradle 62 to move the
package P in a direction in which the package P is moved closer
to the driving roller 61 (see the black arrow in FIG. 7). In this
case, the operation cart 20 separates the reverse-rotation roller
22 from the package P by moving the reverse-rotation roller 22 from
the contacting position to the receded position (see the black arrow
in FIG. 7) . Thus, the reverse-rotation roller 22 is separated from
the package P immediately before the package P makes contact with
the driving roller 61. That is, immediately before the package P
is moved by the cradle 62 and the package P makes contact with the
driving roller 61, the control section 40 controls the driving
section 23 to separate the reverse-rotation roller 22 from the
package P.
In the spinning machine 100, since the package P makes contact
with the driving roller 61 immediately after the reverse-rotation
roller 22 separates from the package P, the package P does not
reversely rotate unintendedly. The spun yarn Y thus can be
prevented from slackening.
Next, with reference to FIG. 8, FIG. 9A, and FIG. 9B, a
structure and an operation of the driving section 23 will be
described. In FIG. 8, FIG. 9A, and FIG. 9B, black arrows indicate
a movement direction of each member of the driving section 23.
The driving section 23 includes an electric motor 23a, an arm
23b, a sub-arm 23c, a pneumatic actuator 23d, and a lever 23e.
The electric motor 23a is mounted to one end of the arm 23b.
In the present embodiment, the electric motor 23a is a servo motor.
The electric motor 23a may be a stepping motor or the like, and
is not limited to any type.
The arm 23b is mounted in a freely swinging manner with a swing
shaft SHI as a center. A first pulley 23ba and a second pulley 23bb
are arranged inside the arm 23b. The first pulley 23ba is rotated
by the electric motor 23a. The second pulley 23bb is rotated by
a belt 23bc wound around the second pulley 23bb and the first pulley
23ba.
The sub-arm 23c is mounted in a freely swinging manner with
a swing shaft SH2 as a center. A third pulley 23ca and a fourth
pulley 23cb are provided inside the sub-arm 23c. The third pulley
23ca is mounted to the second pulley 23bb provided inside the arm
23b. The fourth pulley 23cb is rotated by a belt 23cc wound around
the fourth pulley 23cb and the third pulley 23ca. The
reverse-rotation roller 22 is mounted on the rotation shaft of the
fourth pulley 23cb.
The pneumatic actuator 23d includes a cylinder 23da, a piston
23db, and a rod 23dc. When air fed from an air supply source (not
illustrated) is supplied to the cylinder 23da, the piston 23db is
slidably moved in a direction in which the piston 23db moves closer
to the package P (see FIG. 9B) . The rod 23dc mounted to the piston
23db is thus slidably moved with the piston 23db, and the lever
23e is swung in a direction in which the lever 23e moves away from
the package P (see FIG. 9B). As a result, the reverse-rotation
roller 22 is moved to a receded position, which is a position located
away from the package P (see FIG. 9B) . When the air in the cylinder
23da is sucked by a negative pressure pipe (not illustrated) , the
piston 23db is slidably moved in a direction in which the piston
23db moves away from the package P (see FIG. 9A). The rod 23dc
mounted to the piston 23db is thus slidably moved with the piston
23db, and the lever 23e is swung in a direction in which the lever
23e moves closer to the package P (see FIG. 9A) . As a result, the
reverse-rotation roller 22 is moved to a contacting position, which
is a position where the reverse-rotation roller 22 makes contact
with the package P (see FIG. 9A) . That is, the pneumatic actuator
23d is a double-acting pneumatic actuator.
The lever 23e is mounted in a freely swinging manner with a
pin PI of the rod 23dc of the pneumatic actuator 23d as a center.
The lever 23e is mounted in a freely swinging manner with a pin
P2 arranged on the sub-arm 23c as a center. One end (a first end)
of the lever 23e is mounted to the rod 23dc, and the other end (a
second end) of the lever 23e is mounted to the sub-arm 23c.
The operation of the driving section 23 will be hereinafter
described. First, with reference to FIG. 9A, a description will
be made on the operation of when making the reverse-rotation roller
22 to contact with the package P.
The control section 40 transmits a control signal to an
electromagnetic valve or the like (not illustrated) and causes the ,
air in the cylinder 23da to be sucked. The piston 23db is thus
slidably moved, and the rod 23dc mounted to the piston 23db is moved
in a direction in which the piston 23db retreats into the cylinder
23da. Therefore, the pneumatic actuator 23d swings the lever 23e
mounted to the rod 23dc.
The lever 23e swings the sub-arm 23c with the swing shaft SH2
as a center, and swings the arm 23b with the swing shaft SHI as
a center. Specifically, since the sub-arm 23c is mounted in a freely
swinging manner with the swing shaft SH2 as a center, the sub-arm
23c is swung accompanying the swinging of the lever 23e. Since the
arm 23b and the sub-arm 23b are respectively mounted in a freely
swinging manner with the swing shaft SHI as a center, the arm 23b
is swung accompanying the swinging of the lever 23e. The driving
section 23 thus can move the reverse-rotation roller 22 such that
the reverse-rotation roller 22 makes contact with the package P.
Thereafter, the control section 40 transmits a control signal
to a relay or the like (not illustrated) to pass an electric current
to the electric motor 23a. The reverse-rotation roller 22 thus
starts to rotate, and the package P making contact with the
reverse-rotation roller 22 also starts to rotate.
Next, with reference to FIG. 9B, a description will be made
of the operation of when separating the reverse-rotation roller
22 from the package P.
The control section 40 transmits a control signal to the relay
or the like (not illustrated) to shield the power supply of the
electric motor 23a. The reverse-rotation roller 22 thus stops
rotating, and the package P that has been rotating while making
contact with the reverse-rotation roller 22 also stops rotating.
Thereafter, the control section 40 transmits a control signal
to the electromagnetic valve or the like (not illustrated) to supply
the air to the cylinder 23da. The piston 23db is thus slidably moved,
and the rod 23dc mounted to the piston 23db is moved in a direction
in which the piston 23db advances from the cylinder 23da. The
pneumatic actuator 23d swings the lever 23e mounted to the rod 23dc.
The lever 23e swings the sub-arm 23c with the swing shaft SH2
as a center, and swings the arm 23b with the swing shaft SHI as
a center. Specifically, since the sub-arm 23c is mounted in a freely
swinging manner with the swing shaft SH2 as a center, the sub-arm
23c is swung accompanying the swinging of the lever 23e. Since the
arm 23b and the sub-arm 23c are respectively mounted in a freely
swinging manner with the swing shaft SHI as a center, the arm 23b
is swung accompanying the swinging of the lever 23e. The driving
section 23 thus can move the reverse-rotation roller 22 such that
the reverse-rotation roller 22 is separated from the package P.
As described above, the driving section 23 of the present
embodiment uses the pneumatic actuator 23d to move the
reverse-rotation roller 22. The spinning machine 100 thus can
control the timing in which the reverse-rotation roller 22 is
separated from the package P at high accuracy. Therefore, since
the package P can be made into contact with the driving roller 61
immediately after separating the reverse-rotation roller 22 from
the package P, the package P does not reversely rotate unintendedly.
The spun yarn Y thus can be prevented from slackening.
Even if the outer diameter of the package P differs, the
difference in the contact pressure of the reverse-rotation roller
22 and the package P can be reduced. The deformation of the package
P and the degradation in the quality of the spun yarn Y wound into
the package P thus can be prevented.
Next, with reference to FIG. 10, a structure of the spinning
section 3 will be described. The spinning section 3 is a so-called
pneumatic spinning device adapted to twist the fiber bundle F by
the whirling airflow. In FIG. 10, black arrows indicate the feeding
direction of the fiber bundle F and the spun yarn Y, and white arrows
indicate a flowing direction of the supplied air.
The spinning section 3 generates the whirling airflow in a
spinning chamber SC by an airflow injected from a nozzle block 33,
and twists the fiber bundle F with such a whirling airflow. The
spinning chamber SC is divided into a space SCI formed between a
fiber guide 31 and a spindle 32, and a space SC2 formed between
the spindle 32 and the nozzle block 33.
In the space SCI, a trailing end of the fibers constituting
the fiber bundle F is reversed by the whirling airflow (see chain
double dashed lines in FIG. 10). In the space SC2, the trailing
end of the reversed fibers is whirled by the whirling airflow (see
chain double dashed lines in FIG. 10). The fibers whirled by the
whirling airflow are sequentially wound around fibers at a center
portion. In this manner, the spinning section 3 can twist the fiber
bundle F and spin the fiber bundle F into the spun yarn Y.
In the spinning section 3, the fiber guide 31 is provided with
a needle 31n. The needle 31n guides the fiber bundle F to a fiber
passage 32h, and prevents the twists of the fiber bundle F from
being transmitted upstream. However, the needle 31n may be
omitted.
As described above, since the spinning section 3 adapted to
twist the fiber bundle F with the whirling airflow is arranged in
the spinning unit 10, the production efficiency of the spun yarn
Y in each spinning unit 10 can be improved, and the production
efficiency of the package P in the spinning machine 100 can be
improved.
The spinning machine 100 according to one embodiment of the
present invention has been described above, but the present
invention is not limited to the above embodiment, and the structure
described above can be changed to the following structure, for
example.
In the embodiment described above, the braking section 21,
the reverse-rotation roller 22, the driving section 23, the guiding
section 24, and the yarn joining section 25 are arranged in the
operation cart 20, but the braking section 21, the reverse-rotation
roller 22, the driving section 23, the guiding section 24, and the
yarn joining section 25 may be arranged in each spinning unit 10.
A driving section of the drafting section 2 and a driving section
of the winding section 6 may be independently arranged in each
spinning unit 10, and an independent winding operation may be
carried out in each spinning unit 10.
In the embodiment described above, a plurality of spinning
units 10, the operation cart 20, and the doffing cart 30 are
controlled by the control section 40, but a unit control section
for individually controlling each spinning unit 10 may be arranged
in each spinning unit 10. In this case, the control section 40
collectively controls the plurality of spinning units 10.
In the embodiment described above, the spun yarn Y is cut by
the cutter 41, but the supply of air to the spinning section 3 may
be stopped and the spun yarn Y may be cut by interrupting the
production of the spun yarn Y by the spinning section 3.
In the embodiment described above, the reverse-rotation
roller 22 is moved by the pneumatic actuator 23d, but the
reverse-rotation roller 22 may be moved by an electric motor or
a cam mechanism.
In the embodiment described above, the pneumatic actuator 23d
is a double-acting pneumatic actuator, but the reverse-rotation
roller 22 may be moved by a single-acting pneumatic actuator and
an urging member such as a spring. For example, the single-acting
pneumatic actuator may be used to move the reverse-rotation roller
22 to the contacting position, and the urging member such as the
spring may be used to move the reverse-rotation roller 22 to the
receded position. Since the urging force of the urging member such
as the spring changes by displacement of the urging member, the
difference in the contact pressure of the reverse-rotation roller
22 and the package P becomes large depending on the outer diameter
of the package P. Therefore, the pneumatic actuator 23d is
preferably a double-acting pneumatic actuator.
In FIG. 1, the spinning machine 100 is illustrated to include
one operation cart 20 and one doffing cart 30. According to the
number of the spinning units 10 arranged in the spinning machine
100, a plurality of operation carts 20 and/or a plurality of doffing
carts 30 may be arranged in the spinning machine 100.
The term immediately before is intended to mean a time period
that is sufficiently short to prevent the yarn from slackening.
If the package and the driving roller are made to contact one another
while the reverse-rotation roller is still making contact with the
package, the reverse-rotation roller becomes an obstacle. If the
reverse-rotation roller is separated from the package long before
the package is brought into contact with the driving roller, the
yarn may slacken. Therefore, the period of time in which the package
is free (that is, when the package is not making contact with the
reverse-rotation roller and the driving roller) is preferably
minimized as much as possible. Specifically, such a period of time
is very close to 0 seconds but should be different from 0 seconds.
In embodiments of the invention, the reverse-rotation roller and
the package are separated less than 1 second, less than 0.5 seconds
or less than 0.1 second before the package reaches the contacting
position.
According to an aspect of the present invention, a spinning
machine includes a plurality of spinning units, each spinning unit
being adapted to wind a spun yarn to form a package. The spinning
machine includes a driving roller adapted to make contact with the
package to rotate the package in a winding direction, a cradle
adapted to move the package to a contacting position and a receded
position with respect to the driving roller, a reverse-rotation
roller adapted to make contact with the package to rotate the package
in an unwinding direction that is in an opposite direction of the
winding direction, a driving section adapted to make the package
and the reverse-rotation roller to contact with or separated from
one another, and a control section adapted to control the driving
section to separate the reverse-rotation roller and the package
immediately before the package reaches the contacting position with
respect to the driving roller by the package being moved by the
cradle.
Since the package makes contact with the driving roller
immediately after the reverse-rotation roller is separated from
the package, the package does not reversely rotate unintendedly.
Accordingly, the spun yarn can be prevented from slackening.
The control section is adapted to control the driving section
such that a contact pressure of the reverse-rotation roller and
the package is substantially constant regardless of an outer
diameter of the package. Even if the outer diameter of the package
differs, a difference in the contact pressure of the
reverse-rotation roller and the package can be reduced.
Accordingly, deformation of the package and degradation in quality
of the spun yarn wound into the package thus can be prevented.
The driving section is a pneumatic actuator. A timing in
which the reverse-rotation roller separates from the package can
be controlled at high accuracy. Therefore, since the package makes
contact with the driving roller immediately after the
reverse-rotation roller is separated from the package, the package
does not reversely rotate unintendedly. Accordingly, the spun yarn
can be prevented from slackening. Even if the outer diameter of
the package differs, the difference in the contact pressure of the
reverse-rotation roller and the package can be reduced.
Accordingly, the deformation of the package and the degradation
in the quality of the spun yarn wound into the package can be
prevented.
The spinning machine further includes an operation cart
adapted to travel to one of the spinning units when a continuation
of the spun yarn is disconnected in such spinning unit and to perform
a yarn joining operation. The operation cart includes the
reverse-rotation roller, the driving section, a braking section
adapted to brake rotation of the package, a guiding section adapted
to catch and guide the disconnected spun yarn, and a yarn joining
section adapted to join yarn ends of the disconnected spun yarn.
A structure of each spinning unit thus can be simplified, and a
structure of the spinning machine can be simplified.
Each of the spinning units includes a spinning section adapted
to twist a fiber bundle by a whirling airflow. Accordingly,
production efficiency of the spun yarn in each spinning unit thus
can be improved, and production efficiency of the package in the
spinning machine can be improved.

WE CLAIM:
1. A spinning machine comprising:
a plurality of spinning units, each spinning unit being
adapted to wind a spun yarn to form a package,
a driving roller adapted to make contact with the package to
rotate the package in a winding direction,
a cradle adapted to move the package to a contacting position
and a receded position with respect to the driving roller,
a reverse-rotation roller adapted to make contact with the
package to rotate the package in an unwinding direction that is
in an opposite direction of the winding direction,
a driving section adapted to make the package and the
reverse-rotation roller to contact with or separated from one
another, and
a control section adapted to control the driving section to
separate the reverse-rotation roller and the package immediately
before the package reaches the contacting position with respect
to the driving roller by the package being moved by the cradle.
2. The spinning machine according to claim 1, wherein the
control section is adapted to control the driving section such that
a contact pressure of the reverse-rotation roller and the package
is substantially constant regardless of an outer diameter of the
package.
3. The spinning machine according to claim 1 or claim 2,
wherein the driving section includes a pneumatic actuator.
4. The spinning machine according to any one of claim 1
through claim 3, further comprising an operation cart adapted to
travel to one of the spinning units when a continuation of the spun
yarn is disconnected in such spinning unit and to perform a yarn
joining operation,
wherein the operation cart includes:
the reverse-rotation roller,
the driving section,
a braking section adapted to brake rotation of the
package,
a guiding section adapted to catch and guide the disconnected
spun yarn, and
a yarn joining section adapted to join yarn ends of the
disconnected spun yarn.
5. The spinning machine according to any one of claim 1
through claim 4, wherein each of the spinning units includes a
spinning section adapted to twist a fiber bundle by a whirling
airflow.
6. A spinning machine, substantially as herein described
with reference to accompanying drawings and example.