BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention generally relates to a spinning method performed by using an air spinning device and the air spinning device.

2. Description of the Related Art

Air spinning devices that produce a spun yarn by twisting a fiber bundle by utilizing a swirling airflow are known in the art. Such an air spinning device supplies air into a spinning chamber to generate a swirling airflow that causes fibers, which form a fiber bundle, to swing, thereby producing a spun yarn (see, for example, Japanese published unexamined applications 2003-193337 and H6-41822).

The air spinning devices cause fibers to swing by utilizing a swirling airflow, and hence the end product is likely to be influenced by the fiber characteristics of a fiber bundle. Accordingly, the air spinning machines have a problem that twisting firmness of a produced spun yarn varies depending on the fiber characteristics, such as an average fiber length, of a fiber bundle.

Therefore, there has been a need for an air spinning device capable of performing spinning according to the fiber characteristics and establishing a spinning method performed by using the air spinning device.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an air spinning device capable of performing spinning according to fiber characteristics and an air spinning method performed by using the air spinning device.

According to one aspect of the present invention, an air spinning device is prepared to execute a spinning method. The air spinning device includes a fiber guide in which a fiber introducing passage is defined, and a spindle in which a fiber passageway is defined. When a spun yarn is to be produced from a fiber bundle having an average fiber length longer than or equal to 32 mm, an air spinning device in which the spindle and the fiber guide are separated by a distance longer than or equal to 2.6 mm and shorter than or equal to 4.1 mm is prepared. Finally, a spun yarn is produced from a fiber bundle by using the prepared air spinning device.

According to another aspect of the present invention, an air spinning device is prepared to execute a spinning method. The air spinning device includes a fiber guide in which a fiber introducing passage is defined, and a spindle in which a fiber passageway is defined. When a spun yarn is to be produced from a fiber bundle having an average fiber length shorter than 32 mm, an air spinning device in which the spindle and the fiber guide are separated by a distance longer than or equal to 1.6 mm and shorter than 2.6 mm is prepared. Finally, a spun yarn is produced from a fiber bundle by using the prepared air spinning device.

According to still another aspect of the present invention, an air spinning device that produces a spun yarn from a fiber bundle whose average fiber length is longer than or equal to 32 mm includes a fiber guide in which a fiber introducing passage is defined, and a spindle in which a fiber passageway is defined. It is preferable that the spindle and the fiber guide are separated by a distance longer than or equal to 2.6 mm and shorter than or equal to 4.1 mm.

According to still another aspect of the present invention, an air spinning device that produces a spun yarn from a fiber bundle whose average fiber length is less than 32 mm includes a fiber guide in which a fiber introducing passage is defined, and a spindle in which a fiber passageway is defined. The spindle and the fiber guide are separated by a distance longer than or equal to 1.6 mm and shorter than 2.6 mm.

The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an overall configuration of a spinning unit according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a drafting device of the spinning unit shown in FIG. 1;

FIG. 3 is a schematic diagram of an air spinning device of the spinning unit shown in FIG. 1;

FIG. 4 is a schematic diagram of the air spinning device shown in FIG. 3 that does not include a needle;

FIG. 5 is a schematic diagram of a yarn-defect detecting device of the spinning unit shown in FIG. 1;

FIG. 6 is a schematic diagram of a tension stabilizer of the spinning unit shown in FIG. 1;

FIG. 7 is a schematic diagram illustrating how a distance D between a spindle and a fiber guide shown in FIG. 3 affects rolling endurance RP;

FIG. 8 is another schematic diagram illustrating how the distance D between the spindle and the fiber guide affects the rolling endurance RP; and

FIG. 9 is a schematic diagram of an example screen displaying, for each type of a fiber bundle, suitable one of the air spinning devices.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Exemplary embodiments of the present invention are described in detail below with reference to the accompanying drawings.

An overall configuration of a spinning unit 1 according to an embodiment of the present invention is described below with reference to FIG. 1. The spinning unit 1 is a spinning apparatus that produces a spun yarn Y from a fiber bundle (hereinafter, "sliver") F and produces a package P. The spinning unit 1 includes a sliver supplying unit 4, a drafting device 5, an air spinning device 6, a yarn-defect detecting device 7, a tension stabilizer 8, and a winding device 9 that are arranged in this order along a feed direction of the sliver F and the spun yarn Y.

The sliver supplying unit 4 supplies the sliver F, from which the spun yarn Y is to be produced, to the drafting device 5. The sliver supplying unit 4 includes a sliver casing 41 and a sliver guide 42 (see FIG. 2). The sliver F stored in the sliver casing 41 is supplied to the drafting device 5 through the sliver guide 42.

The drafting device 5 makes the thickness of the sliver F uniform by drafting the sliver F. As shown in FIG. 2, the drafting device 5 includes four pairs of draft rollers, or, more specifically, a pair of back rollers 51, a pair of third rollers 52, a pair of middle rollers 53, and a pair of front rollers 54 arranged in this order along the feed direction of the sliver F. Note that arrows shown in FIG. 2 indicate the feed direction of the sliver F.

Of the four pairs of draft rollers, the draft rollers 51 include a bottom roller 51A and a top roller 51B, the draft rollers 52 include a bottom roller 52A and a top roller 52B, the draft rollers 53 include a bottom roller 53A and a top roller 53B, and the draft rollers 53 include a bottom roller 54A and a top roller 54B. An apron band 53C is arranged around the bottom roller 53A and another apron band 53C is arranged around the top roller 53B of the pair of middle rollers 53. The apron bands 53C are made of material such as leather or synthetic rubber.

The bottom rollers 51A, 52A, 53A, and 54A are rotated in the same direction by a driving device (not shown). The top rollers 51B, 52B, 53B, and 54B are rotated in the same direction by rotations of the bottom rollers 51A, 52A, 53A, and 54A. The pairs of draft rollers 51, 52, 53, and 54 are configured to be in order of an increasing rotation speed along the feed direction of the sliver F. In the drafting device 5 configured in this way, a feeding speed of the sliver F pinched between the pairs of draft rollers 51, 52, 53, and 54 increases each time the sliver F passes between one of the pairs of draft rollers 51, 52, 53, and 54, to thus be drafted between adjacent pairs of the draft rollers. The drafting device 5 can make the thickness of the sliver F uniform by drafting the sliver F in this way.

The air spinning device 6 twists the drafted sliver F, thereby producing the spun yarn Y. As shown in FIG. 3, the air spinning device 6 includes a fiber guide 61, a spindle 62, and a nozzle block 63. Solid arrows shown in FIG. 3 indicate the feed direction of the sliver F and the spun yarn Y. Hollow arrows shown in FIG. 3 indicate an airflow direction of supplied air.

The fiber guide 61 is a member that partially defines a spinning chamber SC. The sliver F drafted by the drafting device 5 passes through the fiber guide 61 to the spinning chamber SC. More specifically, the sliver F passes through a fiber introducing passage 61g, which communicates with the spinning chamber SC, of the fiber guide 61 to the spinning chamber SC. A needle 61n serving as a guide of the sliver F by causing the sliver F to run therealong is provided in the fiber guide 61 in a manner to project into the spinning chamber SC.

The spindle 62 is a member that partially defines the spinning chamber SC. The spun yarn Y twisted in the spinning chamber SC is fed through a fiber passageway 62s, which communicates with the spinning chamber SC, of the spindle 62 to a downstream side in the yarn feed direction of the air spinning device 6.

The nozzle block 63 is a member that partially defines the spinning chamber SC. A plurality of air holes 63a communicating with the spinning chamber SC is defined in the nozzle block 63. Air delivered by application of pressure from an air pressure conveying device (not shown) is supplied to the spinning chamber SC through the air holes 63a. The air holes 63a defined in the nozzle block 63 communicate with the spinning chamber SC such that air jetted through the air holes 63a flows in the same direction around a central axis of the spinning chamber SC. Thus, the air spinning device 6 is capable of generating a swirling airflow inside the spinning chamber SC (see the hollow arrows shown in FIG. 3).

The spinning chamber SC is described in more detail below. The spinning chamber SC is a space surrounded by the fiber guide 61, the spindle 62, and the nozzle block 63. More specifically, the spinning chamber SC is a space surrounded by the substantially conical spindle 62 that is inserted from one side relative to a substantially conical through hole 63p in the nozzle block 63 and the fiber guide 61 attached onto the other side of the nozzle block 63. The shape of the through hole 63p is not limited to such a substantially conical shape as illustrated in FIG. 3, and can be a substantially columnar shape or the like.

Put another way, the shape of the through hole 63p is not limited to a specific shape and can be of any shape so long as a swirling airflow is favorably generated in the spinning chamber SC.

The spinning chamber SC is divided into a space SCI provided between the fiber guide 61 and the spindle 62 and a space SC2 provided between the spindle 62 and the nozzle block 63. In the space SCI, trailing-end portions of fibers that form the sliver F are turned over (see long dashed double-short dashed lines in FIGS. 3 and 4) by the swirling airflow. In the space SC2, the turned-over trailing-end portions of the fibers of the sliver F are swung (see long dashed double-short dashed lines in FIGS. 3 and 4) by the swirling airflow.

In the spinning chamber SC configured in this way, the trailing-end portions of the fibers of the sliver F that runs through the fiber passageway 62s along the needle 61n are turned over and swung. Accordingly, the fibers turned over and swinging are wound around central fibers one after another. The air spinning device 6 is capable of twisting the sliver F by utilizing a swirling airflow in this way, thereby producing the spun yarn Y.

Meanwhile, even though the air spinning device 6 is configured without the needle 61n as shown in FIG. 4, the same object and effect according to the present invention are achieved. The scope of the present invention also encompasses such a modification. In the air spinning device 6 configured in such a way, the sliver F is caught at a downstream end portion of the fiber guide 61 and introduced into the fiber passageway 62s of the spindle 62.

The yarn-defect detecting device 7 detects a defect produced in the spun yarn Y. As shown in FIG. 5, the yarn-defect detecting device 7 includes a light source 71, a light-receiver 72, and a casing 73. Arrows shown in FIG. 5 indicate the direction of light emitted from the light source 71.

The light source 71 is a semiconductor device, or, put another way, a light-emitting diode, that emits light in response to application of forward voltage thereto. The light source 71 is arranged so as to illuminate the spun yarn Y with the light emitted from the light source 71.

The light-receiver 72 is a semiconductor device, or, put another way, a phototransistor, that can control electric current with optical signals. The light-receiver 72 is arranged so as to receive the light emitted from the light source 71.

The casing 73 is a member that holds the light source 71 and the light-receiver 72 at predetermined positions. A yarn passage 73a, through which the spun yarn Y passes, is defined in the casing 73. The casing 73 holds the light source 71 and the light-receiver 72 such that the light source 71 and the light-receiver 72 face each other with the spun yarn Y therebetween.

In the yarn-defect detecting device 7 configured in this way, an amount of light received by the light-receiver 72 can be calculated by subtracting light shielded by the spun yarn Y from the light emitted from the light source 71 to illuminate the spun yarn Y. The yarn-defect detecting device 7 is capable of measuring the amount of received light according to yarn thickness and therefore can detect a defect in the spun yarn Y.

Defects that can be detected by the yarn-defect detecting device 7 include anomalies, for example, that a portion of the spun yarn Y is too thick or too thin, and a foreign matter, such as a polypropylene foreign matter, interposed into the spun yarn Y. The yarn-defect detecting device 7 can adopt an electrical capacitance sensor in lieu of the optical sensor described above.

The tension stabilizer 8 maintains proper tension on the spun yarn Y and stabilizes the tension. As shown in FIG. 6, the tension stabilizer 8 includes a roller 81, a power output section 82, and an unwinding member 83. Note that arrows shown in FIG. 6 indicate the feed direction of the spun yarn Y.

The roller 81 is a substantially cylindrical rotary member used in pulling out the spun yarn Y from the air spinning device 6 and winding the spun yarn Y around itself. The roller 81 is arranged on a rotary shaft 82a of the power output section 82 and rotated by the power output section 82. The spun yarn Y pulled out from the air spinning device 6 is wound around an outer peripheral surface of the roller 81.

As the power output section 82, an electric motor that is driven on electric power supplied thereto is used. The power output section 82 rotates the roller 81 while maintaining the rotation speed of the roller 81 at a predetermined value. This makes it possible to wind the spun yarn Y around the roller 81 at a constant winding speed.

The unwinding member 8 3 is a threading member that rotates in combination with or separately from the roller 81 to thereby assist unwinding of the spun yarn Y. The unwinding member 83 is provided on its one end to a rotary shaft 84 of the roller 81. A portion on the other end of the unwinding member 83 is curved toward the outer peripheral surface of the roller 81. By hooking the spun yarn Y on the curved portion, the unwinding member 83 unwinds the spun yarn Y from the roller 81. A permanent magnet that exerts a resisting force against rotation of the unwinding member 83 is provided at a basal portion of the rotary shaft 84, to which the unwinding member 83 is attached.

The unwinding member 83 configured in this way rotates in combination with the roller 81 when a tension placed on the spun yarn Y is relatively weak and overcome by the resisting force. In contrast, the unwinding member 83 rotates separately from the roller 81 when the tension placed on the spun yarn Y is relatively strong to overcome the resisting force. The tension stabilizer 8 can thus cause the unwinding member 83 to rotate in combination with or separately from the roller 81 depending on the tension placed on the spun yarn Y, thereby adjusting an unwinding speed of the spun yarn Y. The tension stabilizer 8 maintains a proper tension on the spun yarn Y and stabilizes the tension in this way.

Meanwhile, also when the spun yarn Y that is cut is to be spliced by a splicer (not shown), the tension stabilizer 8 can wind the spun yarn Y around the outer peripheral surface of the roller 81 to store the spun yarn Y. The tension stabilizer 8 can therefore take up a slack in the spun yarn Y.

The winding device 9 winds the spun yarn Y to thereby form a substantially cylindrical (cheese-shaped) package P. The winding device 9 includes a driving roller 91 and a cradle (not shown). The cradle rotatably supports a bobbin 92.

The driving roller 91 is a rotary member that rotates to cause the bobbin 92 and the package P to be rotated by rotation of the driving roller 91. The driving roller 91 adjusts its rotation speed according to change in the outer diameter of the package P, thereby maintaining the circumferential velocity of the package P constant. This makes it possible to wind the spun yarn Y on the bobbin 92 at a constant winding speed.

The bobbin 92 is a substantially cylindrical rotary member around which the spun yarn Y is wound. The bobbin 92 is rotated by the rotation of the driving roller 91 that rotates in contact with the outer peripheral surface of any one of the bobbin 92 and the package P. In the winding device 9, a traversing device (not shown) causes the spun yarn Y to be traversed to prevent unbalanced winding of the spun yarn Y on the package P.

In the winding device 9 configured in this way, the spun yarn Y introduced to the bobbin 92 is wound, without being unbalanced, on the outer peripheral surface of the bobbin 92.

The winding device 9 can form the substantially cylindrical (cheese-shaped) package P in this way. The package P to be formed by the winding device 9 is not limited to the substantially cylindrical (cheese-shaped) package P shown in FIG. 1. The winding device 9 can also form the package P having a substantially conical shape.

The reason behind the need for establishing the spinning method performed by using the air spinning device 6 capable of spinning according to fiber characteristics and providing the air spinning device 6 capable of spinning according to fiber characteristics is described below.

As described above, the air spinning device 6 produces the spun yarn Y by twisting the sliver F by utilizing the swirling airflow. More specifically, in the space SCI of the spinning chamber SC, the trailing-end portions of the fibers that form the sliver F are turned over (see the long dashed double-short dashed line in FIGS. 3 and 4) by the swirling airflow. In the space S2 of the spinning chamber SC, the trailing-end portions of the fibers that form the sliver F are swung (see the long dashed double-short dashed line in FIGS. 3 and 4) by the swirling airflow.

Now assume that fibers to be spun are synthetic fibers having a relatively long average fiber length of 32 millimeters (mm) to 51 mm. Synthetic fibers generally possess high stiffness as their inherent material property. Accordingly, if a distance D between the spindle 62 and the fiber guide 61 is shorter than a predetermined value (e.g., 2.6 mm), trailing-end portions of the synthetic fibers are hard to be turned over. As a result, the spun yarn Y that is loosely twisted is produced. More specifically, if the distance D between the spindle 62 and the fiber guide 61 is relatively short (e.g., shorter than 2.6 mm), only a small number of the trailing-end portions of the synthetic fibers are moved by and along the swirling airflow. This makes it difficult to turn over a sufficient number of the trailing-end portions. Accordingly, the number of the synthetic fibers that are swung in the space SC2 is reduced. As a result, a loosely-twisted spun yarn (loose yarn) Y is produced.

In contrast, if the distance D between the spindle 62 and the fiber guide 61 is longer than the predetermined value (e.g., 2.6 mm), a sufficient number of the trailing-end portions of the synthetic fibers are turned over. As a result, the spun yarn Y that is firmly twisted is produced. More specifically, if the distance D between the spindle 62 and the fiber guide 61 is relatively long (e.g., 2.6 mm or longer), the trailing-end portions of the synthetic fibers are moved by and along the swirling airflow easily, and hence the sufficient number of the trailing-end portions is turned over. Accordingly, the synthetic fibers in a state where the sufficient number of the trailing-end portions of the synthetic fibers are wound around central fibers in the space SC2 are introduced into the fiber passageway 62s. As a result, a firmly-twisted spun yarn (firm yarn) Y is produced.

However, if the distance D between the spindle 62 and the fiber guide 61 is too long (e.g., longer than 4.1 mm), both ends of the synthetic fibers are swung in the spinning chamber SC without being restricted by either of the fiber guide 61 and the spindle 62. Accordingly, the synthetic fibers are discharged to the outside of the air spinning device 6 more frequently. As a result, fiber loss increases, which is disadvantageous. Furthermore, as the distance D increases, the volumetric capacity of the spinning chamber SC increases, and hence the amount of air that needs to be used in producing the swirling airflow also increases. Accordingly, the need for increasing the size of the air pressure conveying device arises. This requires upsizing of the spinning unit 1, which is also disadvantageous.

The description about the distance D and the firmness of the spun yarn Y holds true not only for a case where the entire sliver F is formed with synthetic fibers, but also for a case where the sliver F of natural fibers contains a relatively high proportion of synthetic fibers.

Now assume that fibers to be spun are natural fibers having a relatively short average fiber length of, for example, shorter than 32 mm. Natural fibers generally possess low stiffness as their inherent material property. However, if the distance D between the spindle 62 and the fiber guide 61 is shorter than a predetermined value (e.g., 1.6 mm), trailing-end portions of the natural fibers cannot be turned over easily. As a result, a spun yarn Y that is loosely twisted is produced. More specifically, if the distance D between the spindle 62 and the fiber guide 61 is relatively short (e.g., shorter than 1.6 mm), only a small number of the trailing-end portions of the natural fibers are moved by and along the swirling airflow. This makes it difficult to turn over a sufficient number of the trailing-end portions. Accordingly, the number of the natural fibers that are swung in the space SC2 is reduced. As a result, a loosely-twisted spun yarn (loose yarn) Y is produced.

In contrast, if the distance D between the spindle 62 and the fiber guide 61 is longer than the predetermined value (e.g., 1.6 mm), a sufficient number of the trailing-end portions of the natural fibers are turned over. As a result, the spun yarn Y that is firmly twisted is produced. More specifically, if the distance D between the spindle 62 and the fiber guide 61 is relatively long (e.g., 1.6 mm or longer), the trailing-end portions of the natural fibers are moved by and along the swirling airflow easily, and the sufficient number of the trailing-end portions are turned over. Accordingly, the natural fibers in a state where the sufficient number of the trailing-end portions of the natural fibers are wound around central fibers in the space SC2 are introduced into the fiber passageway 62s. As a result, a firmly-twisted spun yarn (firm yarn) Y is produced.

However, if the distance D between the spindle 62 and the fiber guide 61 is too long (e.g., longer than 2.6 mm), both ends of the natural fibers are swung in the spinning chamber SC without being restricted by either of the fiber guide 61 and the spindle 62. Accordingly, the natural fibers are discharged to the outside of the air spinning device 6 more frequently. As a result, fiber loss increases, which is disadvantageous. Furthermore, as the distance D increases, the volumetric capacity of the spinning chamber SC increases, and hence the amount of air that needs to be used in producing the swirling airflow also increases. Accordingly, the need for increasing the size of the air pressure conveying device arises. This requires upsizing of the spinning unit 1, which is also disadvantageous.

The description about the distance D and the firmness of the spun yarn Y holds true not only for a case where the entire sliver F is formed with natural fibers, but also for a case where the sliver F of synthetic fibers contains a relatively high proportion of natural fibers and a case where the sliver F is formed with synthetic fibers of which average fiber length is less than 32 mm.

As described above, there is a problem in that the spun yarn Y made by the air spinning device 6 is likely to be influenced by fiber characteristics because the air spinning device 6 causes fibers to swing by utilizing the swirling airflow. Put another way, the air spinning device 6 is disadvantageous in that twisting firmness of the produced spun yarn Y varies according to fiber characteristics, such as an average fiber length.

Accordingly, there is a need for the air spinning device 6 capable of performing spinning according to fiber characteristics and establishing the spinning method performed by using the air spinning device 6.

A spinning method performed by using the air spinning device 6 according to a first embodiment of the present invention is described below.

In the spinning method according to the first embodiment, a scheme for evaluating the quality of the spun yarn Y by using stability of a rolling endurance RP as an index is employed. The rolling endurance RP is a value indicating stability of the spun yarn Y obtained by measuring the number of times the spun yarn Y is rolled until the twists of the spun yarn Y are untwisted. In a case where a yarn structure of the spun yarn Y is highly stable, even when the spun yarn Y is rolled a plurality of times, the spun yarn Y will not be easily untwisted. In this case, a numerical value indicating the rolling endurance RP is relatively large. In contrast, in a case where a yarn structure of the spun yarn Y is less stable, the spun yarn Y will be untwisted immediately when the spun yarn Y is rolled. In this case, the numerical value indicating the rolling endurance RP is relatively small (see Japanese published unexamined application No. 2010-168708 for detail).

In the spinning method according to the first embodiment, when the spun yarn Y is to be produced from the sliver F whose average fiber length is longer than or equal to 32 mm, the distance D between the spindle 62 and the fiber guide 61 of the air spinning device 6 is set to a value from 2.6 mm to 4.1 mm.

The range of the distance D from 2.6 mm to 4.1 mm is determined based on a result of a test carried out by using twisting firmness of the spun yarn Y according to fiber characteristics as a parameter. More specifically, as illustrated in FIG. 7, when the distance D between the spindle 62 and the fiber guide 61 is longer than or equal to 2.6 mm and shorter than or equal to 4.1 mm, the rolling endurance RP is stabilized at a level higher than a reference value B, and hence quality of the spun yarn Y can be stabilized. Meanwhile, the range of the distance D from 2.6 mm to 4.1 mm is applicable to a plurality of types of the sliver F whose average fiber length is longer than or equal to 32 mm and shorter than or equal to 51 mm. Examples of the applicable sliver F include the sliver F of natural fibers, the sliver F of synthetic fibers, and the sliver F of fibers partly containing synthetic fibers.

Thus, in the air spinning device 6 used to execute the spinning method according to the first embodiment, the distance D between the spindle 62 and the fiber guide 61 is set to be longer than or equal to 2.6 mm and shorter than or equal to 4.1 mm. The spinning method according to the first embodiment and the air spinning device 6 used in the spinning method allow stabilizing quality of the spun yarn Y to be produced from the sliver F whose average fiber length is longer than or equal to 32 mm.

Meanwhile, when the spun yarn Y is to be produced from the sliver F whose average fiber length is longer than or equal to 32 mm, it is more effective to set the distance D between the spindle 62 and the fiber guide 61 to be longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm. More specifically, as illustrated in FIG. 7, when the distance D between the spindle 62 and the fiber guide 61 is longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm, the rolling endurance RP increased as well as became stable, and hence quality of the spun yarn Y can be improved. Meanwhile, the range of the distance D from 3.1 mm to 3.6 mm is applicable to a plurality of types of the sliver F whose average fiber length is longer than or equal to 32 mm and shorter than or equal to 51 mm. Examples of the applicable sliver F include the sliver F of natural fibers, the sliver F of synthetic fibers, and the sliver F of fibers partly containing synthetic fibers.
Thus, in the air spinning device 6 used to execute the spinning method according to the first embodiment, it is desirable that the distance D between the spindle 62 and the fiber guide 61 is set to be longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm. The spinning method according to the first embodiment and the air spinning device 6 configured in this way used to perform the spinning method allow improving quality of the spun yarn Y to be produced from the sliver F whose average fiber length is longer than or equal to 32 mm.

Meanwhile, the same objects and effects as the above can be achieved when, for example, the fiber guide 61 and the nozzle block 63 of the air spinning device 6 are formed into one piece. The scope of the present invention also encompasses such a modification. The same objects and effects as the above can be achieved when, for example, the spindle 62 and the nozzle block 63 of the air spinning device 6 are formed into one piece. The scope of the present invention also encompasses such a modification.

A spinning method performed by using the air spinning device 6 according to a second embodiment of the present invention is described below.

In the spinning method according to the second embodiment, when the spun yarn Y is to be produced from the sliver F whose average fiber length is shorter than 32 mm, the distance D between the spindle 62 and the fiber guide 61 of the air spinning device 6 is set to longer than or equal to 1.6 mm and shorter than 2.6 mm.

The range of the distance D from 1.6 mm to 2.6 mm is determined based on a result of a test carried out by using twisting firmness of the spun yarn Y that changes according to fiber characteristics as a parameter. More specifically, as illustrated in FIG. 8, when the distance D between the spindle 62 and the fiber guide 61 is longer than or equal to 1.6 mm and shorter than 2.6 mm, the rolling endurance RP is stabilized at a level higher than the reference value B, and hence quality of the spun yarn Y can be stabilized. Meanwhile, the range of the distance D from 1.6 mm to 2.6 mm is applicable to a plurality of types of the sliver F whose average fiber length is shorter than 32 mm. Examples of the applicable sliver F include the sliver F of natural fibers, the sliver F of synthetic fibers, and the sliver F of fibers partly containing synthetic fibers.

Thus, in the air spinning device 6 used to execute the spinning method according to the second embodiment, the distance D between the spindle 62 and the fiber guide 61 is set to be longer than or equal to 1.6 mm and shorter than 2.6 mm. The spinning method according to the second embodiment and the air spinning device 6 used to execute the spinning method allow stabilizing quality of the spun yarn Y to be produced from the sliver F whose average fiber length is shorter than 32 mm.

Meanwhile, when the spun yarn Y is to be produced from the sliver F whose average fiber length is shorter than 32 mm, it is more effective to set the distance D between the spindle 62 and the fiber guide 61 to be longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm. More specifically, as illustrated in FIG. 8, by setting the distance D between the spindle 62 and the fiber guide 61 to be longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm, the rolling endurance RP becomes more stable, and hence quality of the spun yarn Y can be improved. Meanwhile, the range of the distance D from 1.8 mm to 2.3 mm is applicable to a plurality of types of the sliver F whose average fiber length is shorter than 32 mm. Examples of the applicable sliver F include the sliver F of natural fibers, the sliver F of synthetic fibers, and the sliver F of fibers partly containing synthetic fibers.

Thus, in the air spinning device 6 used for executing the spinning method according to the second embodiment, it is desirable that the distance D between the spindle 62 and the fiber guide 61 is set to be longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm. The spinning method according to the second embodiment and the air spinning device 6 configured in this way used for executing the spinning method allow improving quality of the spun yarn Y to be produced from the sliver F whose average fiber length is shorter than 32 mm.

Meanwhile, the same object and effect as above can be achieved when, for example, the fiber guide 61 and the nozzle block 63 of the air spinning device 6 are formed into one piece. The scope of the present invention also encompasses such a modification. Moreover, the same object and effect as above can be achieved when, for example, the spindle 62 and the nozzle block 63 of the air spinning device 6 are formed into one piece. The scope of the present invention also encompasses such a modification.

The spinning method performed by using the air spinning device 6 can be implemented in a configuration in which a plurality of the fiber guides 61 of different shapes are provided. With this configuration, the distance D is adjusted by replacing the fiber guide 61 to another one of the fiber guides 61. The spinning method can alternatively be implemented in a structure in which a mounting position of the spindle 62 can be changed to achieve adjustment of the distance D. Moreover, the spinning method can be implemented in a configuration in which a plurality of the air spinning devices 6 that differ from one another in the distance D are prepared. With this configuration, the air spinning device 6 is switched to another one of the air spinning devices 6 that is suitable for a type of the sliver F.

The spinning unit 1 includes an input screen 10 for receiving input of information relating to a type of the sliver F. The input screen 10 also functions as a display unit that displays information about the air spinning device 6 suitable for the type of the sliver F. FIG. 9 is a schematic diagram illustrating an example screen displaying, for each type of the sliver F, suitable one of the air spinning devices 6.

For example, when an operator inputs the sliver F of polyester fibers, which are typical synthetic fibers, whose average fiber length is approximately 38 mm, one of the air spinning devices 6 (in FIG. 9, the air spinning device "P") in which the distance D between the spindle 62 and the fiber guide 61 is set to be longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm is displayed. For example, in a situation where an operator has input the sliver F of cotton fibers, which are typical natural fibers, whose average fiber length is approximately 25.4 mm, one of the air spinning devices 6 (in FIG. 9, the air spinning device "Q") in which the distance D between the spindle 62 and the fiber guide 61 is set to be longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm is displayed.

This configuration makes it possible to select one of the air spinning devices 6 suitable for fiber characteristics without fail. Accordingly, a troublesome job that can otherwise be involved in changing the sliver F to be spun to the sliver F having different fiber characteristics is made easier.

In the spinning unit 1 described above, the spun yarn Y spun by the air spinning device 6 is drawn out and temporarily stored by the tension stabilizer 8.

However, the configuration of the spinning unit 1 is not limited to such a configuration. For example, a configuration is allowable in which a delivery roller and a nip roller are arranged downstream of the air spinning device 6, and the delivery roller and the nip roller draw out the spun yarn Y from the air spinning device 6. Moreover, a configuration is allowable in which the tension stabilizer 8 is arranged downstream relative to the delivery roller and the nip roller, and the spun yarn Y drawn out from the air spinning device 6 by the delivery roller and the nip roller is temporarily stored by the tension stabilizer 8. Alternatively, a configuration in which the tension stabilizer 8 is omitted and the winding device 9 directly winds the spun yarn Y can be employed.

The present invention yields the following effects.

According to an aspect of the present invention, when producing a spun yarn from a fiber bundle whose average fiber length is longer than or equal to 32 mm, by using an air spinning device including a spindle and a fiber guide that are separated by a distance longer than or equal to 2.6 ran and shorter than or equal to 4.1 mm, quality of the spun yarn can be stabilized.

According to another aspect of the present invention, when producing a spun yarn from a fiber bundle whose average fiber length is longer than or equal to 32 mm, by using an air spinning device including the spindle and the fiber guide that are separated by a distance longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm, quality of the spun yarn can be improved.

According to still another aspect of the present invention, a spun yarn can be produced from a plurality of types of fiber bundles of which average fiber lengths are longer than or equal to 32 mm and shorter than or equal to 51 mm.

According to still another aspect of the present invention, when producing a spun yarn from a fiber bundle whose average fiber length is shorter than 32 mm, by using an air spinning device including a spindle and a fiber guide that are separated by a distance longer than or equal to 1.6 mm and shorter than 2.6 mm, quality of the spun yarn can be stabilized.

According to still another aspect of the present invention, when producing a spun yarn from a fiber bundle whose average fiber length is shorter than 32 mm, by using an air spinning device including the spindle and the fiber guide that are separated by a distance longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm, quality of the spun yarn can be improved.

According to still another aspect of the present invention, a spun yarn is produced from a fiber bundle whose average fiber length is longer than or equal to 32 mm by using an air spinning device including a spindle and a fiber guide that are separated by a distance longer than or equal to 2.6 mm and shorter than or equal to 4.1 mm. This allows stabilizing the quality of the spun yarn.

According to still another aspect of the present invention, a spun yarn is produced from a fiber bundle whose average fiber length is longer than or equal to 32 mm by using an air spinning device including the spindle and the fiber guide that are separated by a distance longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm. This allows improving the quality of the spun yarn.

According to still another aspect of the invention, a spun yarn can be produced from a plurality of types of fiber bundles of which average fiber length is longer than or equal to 32 mm and shorter than or equal to 51 mm.

According to still another aspect of the present invention, a spun yarn is produced from a fiber bundle whose average fiber length is shorter than 32 mm by using an air spinning device including a spindle and a fiber guide that are separated by a distance longer than or equal to 1.6 mm and shorter than 2.6 mm. This allows stabilizing the quality of the spun yarn.

According to still another aspect of the present invention, a spun yarn is produced from a fiber bundle whose average fiber length is shorter than 32 mm by using an air spinning device including the spindle and the fiber guide that are separated by a distance longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm. This allows improving the quality of the spun yarn.

According to still another aspect of the present invention, an air spinning device suitable for fiber characteristics of the used fiber bundle can be selected without fail. Accordingly, a troublesome job that can otherwise be involved in changing a fiber bundle, from which a spun yarn is to be produced, to another fiber bundle having different fiber characteristics is made easier.

According to a first aspect of the present invention, an air spinning device is prepared to execute a spinning method. The air spinning device includes a fiber guide in which a fiber introducing passage is defined, and a spindle in which a fiber passageway is defined. When a spun yarn is to be produced from a fiber bundle having an average fiber length longer than or equal to 32 mm, an air spinning device in which the spindle and the fiber guide are separated by a distance longer than or equal to 2.6 mm and shorter than or equal to 4.1 mm is prepared. Finally, a spun yarn is produced from the fiber bundle by using the prepared air spinning device.

According to a second aspect of the present invention, the distance between the spindle and the fiber guide in the air spinning device is adjustable, and when a spun yarn is to be produced from a fiber bundle having an average fiber length longer than or equal to 32 mm, it is preferable to adjust the distance between the spindle and the fiber guide to a distance that is longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm is prepared.

According to a third aspect of the present invention, the fiber bundle whose average fiber length is longer than or equal to 32 mm, can be any one of a fiber bundle formed of natural fibers, a fiber bundle formed of synthetic fibers, and a fiber bundle partly containing synthetic fibers. Moreover, it is preferable that an average fiber length of the fiber bundle is longer than or equal to 32 mm and shorter than or equal to 51 mm.

According to a fourth aspect of the present invention, an air spinning device is prepared to execute a spinning method. The air spinning device includes a fiber guide in which a fiber introducing passage is defined, and a spindle in which a fiber passageway is defined. When a spun yarn is to be produced from a fiber bundle having an average fiber length shorter than 32 mm, an air spinning device in which the spindle and the fiber guide are separated by a distance longer than or equal to 1.6 mm and shorter than 2.6 mm is prepared. Finally, a spun yarn is produced from the fiber bundle by using prepared air spinning device.

According to a fifth aspect of the present invention, the distance between the spindle and the fiber guide in the air spinning device is adjustable, and when a spun yarn is to be produced from a fiber bundle having an average fiber length shorter than 32 mm, it is preferable to adjust the distance between the spindle and the fiber guide to a distance that is longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm is prepared.

According to a sixth aspect of the present invention, an air spinning device that produces a spun yarn from a fiber bundle whose average fiber length is longer than or equal to 32 mm includes a fiber guide in which a fiber introducing passage is defined, and a spindle in which a fiber passageway is defined. It is preferable that the spindle and the fiber guide are separated by a distance longer than or equal to 2.6 mm and shorter than or equal to 4.1 mm.

According to a seventh aspect of the present invention, it is preferable that the distance between the spindle and the fiber guide is longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm.

According to an eighth aspect of the present invention, the fiber bundle whose average fiber length is longer than or equal to 32 mm, can be any one of a fiber bundle formed of natural fibers, a fiber bundle formed of synthetic fibers, and a fiber bundle partly containing synthetic fibers. Moreover, it is preferable that an average fiber length of the fiber bundle is longer than or equal to 32 mm and shorter than or equal to 51 mm.

According to a ninth aspect of the present invention, an air spinning device that produces a spun yarn from a fiber bundle whose average fiber length is less than 32 mm includes a fiber guide in which a fiber introducing passage is defined, and a spindle in which a fiber passageway is defined. The spindle and the fiber guide are separated by a distance longer than or equal to 1.6 mm and shorter than 2.6 mm.

According to a tenth aspect of the present invention, it is preferable that the distance between the spindle and the fiber guide is longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm.

According to an eleventh aspect of the present invention, it is preferable that the air spinning device further includes an input unit capable to receiving input of information about a type of the fiber bundle from which the spun yarn is to be produced.

Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.

We claim:

1. A spinning method comprising:
preparing an air spinning device including a spinning chamber in which fibers are swung, a fiber guide in which a fiber introducing passage communicating with the spinning chamber is defined, and a spindle in which a fiber passageway for passage of the fibers swung in the spinning chamber is defined, the preparing including, when a fiber bundle has an average fiber length longer than or equal to 32 mm, preparing an air spinning device in which the spindle and the fiber guide are separated by a distance longer than or equal to 2.6 mm and less than or equal to 4.1 mm; and producing a spun yarn from the fiber bundle by using the prepared air spinning device.

2. The spinning method according to Claim 1, wherein the distance between the spindle and the fiber guide in the air spinning device is adjustable, and the spinning method includes, when the fiber bundle has an average fiber length longer than or equal to 32 mm, adjusting the distance between the spindle and the fiber guide to a distance that is longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm.

3. The spinning method according to Claim 1 or 2, wherein the fiber bundle having the average fiber length longer than or equal to 32 mm is any one of a fiber bundle formed of natural fibers, a fiber bundle formed of synthetic fibers, and a fiber bundle partly containing synthetic fibers, the average fiber length of the fiber bundle being longer than or equal to 32 mm and shorter than or equal to 51 mm.

4. A spinning method comprising:
preparing an air spinning device including a spinning chamber in which fibers are swung, a fiber guide in which a fiber introducing passage communicating with the spinning chamber is defined, and a spindle in which a fiber passageway for passage of the fibers swung in the spinning chamber is defined, the preparing including, when a fiber bundle has an average fiber length shorter than 32 mm, preparing an air spinning device in which the spindle and the fiber guide are separated by a distance longer than or equal to 1.6 mm and shorter than 2.6 mm; and producing a spun yarn from the fiber bundle by using the prepared air spinning device.

5. The spinning method according to Claim 4, wherein the distance between the spindle and the fiber guide in the air spinning device is adjustable, and the spinning method includes, when the fiber bundle has an average fiber length shorter than 32 mm, adjusting the distance between the spindle and the fiber guide to a distance longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm.

6. An air spinning machine that produces a spun yarn from a fiber bundle of which average fiber length is longer than or equal to 32 mm, the air spinning device comprising:
a spinning chamber in which fibers are swung;

a fiber guide in which a fiber introducing passage communicating with the spinning chamber is defined; and

a spindle in which a fiber passageway for passage of the fibers swung in the spinning chamber is defined, wherein the spindle and the fiber guide are separated by a distance longer than or equal to 2.6 mm and shorter than or equal to 4.1 mm.

7. The air spinning device according to Claim 6, wherein the distance between the spindle and the fiber guide is longer than or equal to 3.1 mm and shorter than or equal to 3.6 mm.

8. The air spinning device according to Claim 6 or 7, wherein the fiber bundle is any one of a fiber bundle formed of natural fibers, a fiber bundle formed of synthetic fibers, and a fiber bundle partly containing synthetic fibers, the average fiber length of the fiber bundle being longer than or equal to 32 mm and shorter than or equal to 51 mm.

9. An air spinning device that produces a spun yarn from a fiber bundle of which average fiber length is shorter than 32 mm, the air spinning device comprising:

a spinning chamber in which fibers are swung; a fiber guide in which a fiber introducing passage communicating with the spinning chamber is defined; and

a spindle in which a fiber passageway for passage of the fibers swung in the spinning chamber is defined, wherein the spindle and the fiber guide are separated by a distance longer than or equal to 1.6 mm and shorter than 2.6 mm.

10. The air spinning device according to Claim 9, wherein the distance between the spindle and the fiber guide is longer than or equal to 1.8 mm and shorter than or equal to 2.3 mm.

11. The air spinning device according to any one of Claims 6 to 10, further comprising an input unit capable of receiving input of information about a type of the
fiber bundle from which the spun yarn is to be produced.