BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a yarn joining nozzle, a yarn joining device that includes the yarn joining nozzle, a yarn winding device that includes the yarn joining device, and a yarn joining method.
2. Description of the Related Art
In a state in which yarn ends of two yarns are inserted inside a yarn joining nozzle, in the yarn joining device (splicer) disclosed in Japanese Patent Application Laid-open No. H7-125932, a swirling current is generated inside the yarn joining nozzle by injecting compressed air inside the yarn joining nozzle via an air supply path in a tangential direction of an inner wall surface of the yarn joining nozzle to twist the two yarn ends thereby joining the two yarns.
In such a situation, joining of yarns in which elastic core fibers such as spandex are covered with cover fibers (core yarns) by using the yarn joining device disclosed in Japanese Patent Application Laid-open No. H7-125932 is considered.
When joining such yarns by using such a yarn joining device, as explained above, when a swirling current is generated inside the yarn joining nozzle, two cover fibers are intertwined, and two yarns are joined. However, at this stage, the core fibers of the two yarns are not joined. Therefore, in such a case, there is no core fiber at the joint of the two yarns.
SUMMARY OF THE INVENTION

One object of the present invention is to provide a yarn joining nozzle, a yarn joining device that includes the yarn joining nozzle, a yarn winding device that includes the yarn joining device, and a yarn joining method capable of joining elastic core fibers in addition to intertwining cover fibers when performing yarn joining of yarns in which the core fibers are covered with the cover fibers.
According to one aspect of the present invention, a yarn joining nozzle includes a yarn joining space that extends in a first direction; a yarn inserting gap that extends in the first direction and communicates with the yarn joining space in a second direction that is perpendicular to the first direction, and via which a yarn is inserted into the yarn joining space by moving the yarn in the second direction; and a plurality of injection passages via which compressed air is injected inside the yarn joining space. The yarn joining space includes a first space that is circular when seen from the first direction; a second space arranged away from the first space in the first direction, and is circular when seen from the first direction; and a third space that is positioned between the first space and the second space in the first direction. The plurality of the injection passages includes a first injection passage that includes a first injection port that is open on an inner wall surface of the first space, and extends from the first injection port in a tangential direction of the inner wall surface of the first space when seen from the first direction; a second injection passage that

includes a second injection port that is open on an inner wall surface of the second space, and extends from the second injection port in a tangential direction of the inner wall surface of the second space when seen from the first direction; and a third injection passage that includes a third injection port that is open on an inner wall surface of the third space, and extends from the third injection port toward a direction that is different from a direction in which the yarn inserting gap is present.
According to another aspect of the present invention, a yarn joining device includes the above yarn joining nozzle.
According to still another aspect of the present invention, a yarn winding device includes a yarn supplying section capable of supplying a yarn; a winding section that is arranged at a position away from the yarn supplying section in the first direction and winds the yarn supplied from the yarn supplying section; and the above yarn joining device that is arranged between the yarn supplying section and the winding section in the first direction.
According to still another aspect of the present invention, a yarn joining method is a yarn joining method for joining inside a yarn joining nozzle two yarns, in which elastic core fibers are covered with cover fibers. The yarn joining nozzle includes a yarn joining space that extends in a first direction; and a yarn inserting gap that extends in the first direction and communicates with the yarn joining space in a second direction that is perpendicular to the first

direction, and via which a yarn is inserted into the yarn joining space by moving the yarn in the second direction. The yarn joining space includes a first space that is circular when seen from the first direction; a second space that is arranged away from the first space in the first direction, and is circular when seen from the first direction; and a third space that is positioned between the first space and the second space in the first direction. The yarn joining method includes generating a swirling current inside the yarn joining space by injecting compressed air inside the first space in a tangential direction of an inner wall surface of the first space as seen from the first direction and inside the second space in a tangential direction of an inner wall surface of the second space as seen from the first direction to intertwine the cover fibers of the two yarns; and injecting the compressed air inside the third space in a direction different from a direction in which the yarn inserting gap is present to interlace the core fibers of the two yarns.
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 structural diagram of an automatic winder according to an embodiment of the present invention.
FIG. 2 is a structural diagram of a winding unit that constitutes the automatic winder.
FIG. 3A is a structural diagram of a yarn joining device that shows a state immediately before a yarn is cut by a cutter, FIG. 3B is a structural diagram of the yarn joining device that shows a state in which a yarn end is introduced to an untwisting pipe, and FIG. 3C is a structural diagram of the yarn joining device that shows a state in which an untwisted yarn end is introduced to a yarn joining nozzle.
FIG. 4A is a perspective view of a yarn joining section of the yarn joining device, and FIG. 4B is a perspective view of a nozzle block in which the yarn joining nozzle is removed from the configuration shown in FIG. 4A.
FIG. 5A is a perspective view of the yarn joining nozzle, and FIG. 5B is a perspective view of the yarn joining nozzle when seen from a direction different than that of FIG. 5A.
FIG. 6A is a cross-sectional view along an A-A line shown in FIGS. 5A and 5B, FIG. 6B is a cross-sectional view along a B-B line shown in FIGS. 5A and 5B, and FIG. 6C is a cross-sectional view along a C-C line shown in FIGS. 5A and 5B.
DETAILED DESCRIPTION Exemplary embodiments of the present invention are explained below.

Automatic Winder
As shown in FIG. 1, an automatic winder 1 includes a plurality of winding units 2 ("yarn winding device" according to the present invention) arranged in one direction, a doffing device 3 arranged so as to travel freely along the plurality of the winding units 2 in an arrangement direction thereof, and a machine-frame controlling device 4 that performs control on the entire automatic winder 1. Note that, in the following explanation, "left right direction" refers to a left right direction in which the plurality of the winding units 2 is arranged in FIG. 1. Moreover, in the following explanation, a direction perpendicular to the paper surface of FIG. 1 is considered as a front back direction, and a front side and a back side with respect to the direction perpendicular to the paper surface of FIG. 1 are referred to as "front side" and "back side", respectively.
In the automatic winder 1, the machine-frame controlling device 4 transmits a signal to a not-shown control device arranged separately for each winding unit 2, and the winding unit 2 winds a yarn Y that is unwound from a yarn supplying bobbin B onto a winding tube Q (see FIG. 2) to form a package P. Moreover, when a fully-wound package P is formed in a certain winding unit 2, the doffing device 3 moves to a position facing that winding unit 2, and replaces the fully wound package P with an empty winding tube Q. The machine-frame controlling device 4 controls the operation of the not-shown control device of the winding unit 2, and monitors an operating state of the

entire automatic winder 1 and performs setting, storing and the like of operating parameters.
A detailed configuration of the winding unit 2 will be explained below. The winding unit 2 forms a package P by winding the yarn Y onto the winding tube Q while traversing the yarn Y that is being unwound from the yarn supplying bobbin B. In the present embodiment, the yarn Y is a core yarn in which elastic core fibers such as spandex are covered with cover fibers.
As shown in FIG. 2, the winding unit 2 includes a yarn supplying section 11 that holds the yarn Y of the yarn supplying bobbin B in a suppliable state, a yarn processing performing section 12 that performs various processes on the yarn Y that is unwound from the yarn supplying bobbin B held in the yarn supplying section 11, and a winding section 13 that winds onto the winding tube Q to form the package P the yarn Y that is processed in the yarn processing performing section 12. The yarn supplying section 11, the yarn processing performing section 12, and the winding section 13 are arranged sequentially from bottom to top.
The yarn supplying section 11 includes a bobbin holding section 15 that holds the yarn supplying bobbin B and an unwinding assisting device 16 that assists in unwinding of the yarn Y from the yarn supplying bobbin B. The unwinding assisting device 16 includes a cylindrical body 29 that covers the yarn supplying bobbin B from above. The cylindrical body 29 is raised / lowered by a not-shown motor. In the unwinding assisting device 16, as the unwinding of the yarn Y proceeds, by lowering the cylindrical body 29, bulging

(balloon) of the yarn Y that is being unwound is regulated and the tension of the yarn Y is stabilized.
The winding section 13 includes a cradle 14 that rotatably supports the winding tube Q, and a traversing drum 18. The traversing drum 18 is driven to rotate by a not-shown drum motor. A helical traversing groove 18a is formed on an outer peripheral surface of the traversing drum 18, and the yarn Y is traversed through the traversing groove 18a. By rotating the traversing drum 18 in a state in which the traversing drum 18 is in contact with the package P formed on the winding tube Q while traversing the yarn Y through the traversing groove 18a, the package P is rotated in a winding direction by the contact friction thereof with the traversing drum 18, and the yarn Y unwound from the yarn supplying bobbin B is wound onto the winding tube Q.
The yarn processing performing section 12 arranged between the yarn supplying section 11 and the winding section 13 includes a yarn feeler 19, a tension applying device 20, a yarn joining device 21, and a yarn clearer 22.
The yarn feeler 19 is arranged between the unwinding assisting device 16 and the tension applying device 20, and detects the presence of the traveling yarn Y.
The tension applying device 20 applies a predetermined tension to the traveling yarn Y. In FIG. 2, as an example, a gate-type tension applying device 20 is shown. In the gate-type tension applying device 20, a plurality of fixed gates 20a and a plurality of

moveable gates 20b are alternately arranged in a vertical direction. Therefore, by adjusting the position of the moveable gates 20b in a horizontal direction, the tension is applied to the yarn Y traveling between the fixed gates 20a and the moveable gates 20b.
When the yarn Y is cut by a cutter 22a when the later-explained yarn clearer 22 detects a yarn defect, or when the yarn Y is not detected by the yarn clearer 22 in the case such as when yarn breakage occurs during package winding or when there is no yarn on the yarn supplying bobbin B and the yarn supplying bobbin B is being replaced, the yarn joining device 21 performs yarn joining of a yarn Y1 (see FIGS. 3A to 3C) from the yarn supplying bobbin B (yarn supplying section 11) and a yarn Y2 (see FIGS. 3A to 3C) from the package P (winding section 13).
A lower yarn catching / guiding member 23 that catches the yarn Y1 from the yarn supplying bobbin B and guides the yarn Y1 to the yarn joining device 21 is arranged below the yarn joining device 21, and an upper yarn catching / guiding member 24 that catches the yarn Y2 from the package P and guides the yarn Y2 to the yarn joining device 21 is arranged above the yarn joining device 21. The lower yarn catching / guiding member 23 is pivotable around a shaft 23a, and swings vertically when rotationally driven by a not-shown motor. The upper yarn catching / guiding member 24, too, is pivotable around a shaft 24a, and swings vertically when rotationally driven by a not-shown motor. The lower yarn catching / guiding member 23 and

the upper yarn catching / guiding member 24 are connected to individually-arranged not-shown suction sources.
The lower yarn catching / guiding member 23 includes on an end portion thereof a suction part 23b that sucks and catches a yarn end of the yarn Y1 from the yarn supplying section 11. When in a downward position, the lower yarn catching / guiding member 23 swings upward while holding the yarn end portion of the Y1 in the suction part 23b and guides the yarn Y1 to the yarn joining device 21.
The upper yarn catching / guiding member 24 includes on an end portion thereof a suction mouth 24b that sucks and catches a yarn end of the yarn Y2 from the winding section 13. By first swinging upward from the downward position and moving the suction mouth 24b to a position near a contact point of the package P and the traversing drum 18, the upper yarn catching / guiding member 24 catches a yarn end of the yarn Y2 adhered to a surface of the package P. Subsequently, after catching the yarn end of the yarn Y2, the upper yarn catching / guiding member 24 swings downward from the upward position and guides the caught yarn Y2 to the yarn joining device 21.
The yarn joining device 21 joins the yarn end portion of the yarn Y1 guided by the lower yarn catching / guiding member 23 and the yarn end portion of the yarn Y2 guided by the upper yarn catching / guiding member 24 to form one yarn Y. Configuration, operation, and the like of the yarn joining device 21 will be explained in detail later.

The yarn clearer 22 from time to time acquires information on the thickness of the traveling yarn Y, and based on the thickness information of the yarn Y, detects an abnormal part of the yarn Y that is thicker than a predetermined thickness as the yarn defect. Moreover, the cutter 22a is arranged in the yarn clearer 22, and upon detection of the yarn defect by the yarn clearer 22, the cutter 22a immediately cuts the yarn Y. Yarn Joining Device
Next, configuration of the yarn joining device 21 will be explained in detail. As shown in FIGS. 3A to 3C, the yarn joining device 21 includes an untwisting section 31, a yarn joining section 32, an upper guide plate 33, a lower guide plate 34, yarn shifting levers 35a and 35b, and twist stopping guides 36a and 36b.
The untwisting section 31 untwists the yarn ends of the yarns Y1 and Y2. The untwisting section 31 includes two untwisting pipes 41a and 41b that are arranged at an interval in the vertical direction. The untwisting pipes 41a and 41b are cylindrical members that extend in the front back direction, and are open at respective tip end portions (front end portions) and base end portions (back end portions). Moreover, an injection hole 42 via which compressed air is injected is open on inner wall surfaces of the untwisting pipes 41a and 41b. When the compressed air is injected from the injection hole 42, an air current that flows inside the untwisting pipes 41a and 41b from the tip end portion thereof to the base end portion thereof is generated. By the action of the generated air current,

a suction current is generated at the tip end portions of the untwisting pipes 41a and 41b, and the yarn ends of the yarns Y1 and Y2 can be sucked by the action of the generated suction current. By the action of the air current that flows from the tip end portion to the base end portion, the yarn end of the yarn Y1 inside the untwisting pipe 41a and the yarn end of the yarn Y2 inside the untwisting pipe 41b move intensely inside the respective pipes. Such movement causes the yarn ends to collide against inner walls of the respective pipes. Accordingly, by the action of such collision and the air current, the cover fibers of the yarn end of the yarn Y1 introduced into the untwisting pipe 41a and the cover fibers of the yarn end of the yarn Y2 introduced into the untwisting pipe 41b can be untwisted.
The yarn joining section 32 joins the yarn ends of the yarns Y1 and Y2. Details of the yarn joining section 32 will be explained later.
The upper guide plate 33 is arranged above the untwisting section 31 and the yarn joining section 32. A guide groove 51a to which the yarn Y1 is introduced and a guide groove 52a to which the yarn Y2 is introduced are formed on the upper guide plate 33. The guide groove 51a and the guide groove 52a are arranged at an interval in the left right direction (a direction perpendicular to the paper surface of FIGS. 3A to 3C), and the guide groove 52a is arranged further on the right side (back side with respect to the direction perpendicular to the paper surface of FIGS. 3A to 3C) than the guide groove 51a. Accordingly, when the yarns

Y1 and Y2 are guided to the yarn joining device 21 by the lower yarn catching / guiding member 23 and the upper yarn catching / guiding member 24, the yarn Y1 is introduced to the guide groove 51a from the front side and the yarn Y2 is introduced to the guide grove 52a from the front side.
A cutter 53a and a clamping member 54a are arranged on the upper guide plate 33. The cutter 53a is arranged opposing to the guide groove 51a. The clamping member 54a is arranged opposing to the guide groove 52a.
The lower guide plate 34 is arranged below the untwisting section 31 and the yarn joining section 32. A guide groove 51b to which the yarn Y1 is introduced and a guide groove 52b to which the yarn Y2 is introduced are formed on the lower guide plate 34. The guide groove 51b and the guide groove 52b are arranged at an interval in the left right direction (the direction perpendicular to the paper surface of FIGS. 3A to 3C), and the guide groove 52b is arranged further on the right side (back side with respect to the direction perpendicular to the paper surface of FIGS. 3A to 3C) than the guide groove 51b. The guide grooves 51b and 52b are arranged almost directly under the guide grooves 51a and 52b, respectively. Accordingly, when the yarns Y1 and Y2 are guided to the yarn joining device 21 by the lower yarn catching / guiding member 23 and the upper yarn catching / guiding member 24, the yarn Y1 is introduced to the guide groove 51b from the front side and the yarn Y2 is introduced to the guide grove 52b from the front side.

A cutter 53b and a clamping member 54b are arranged on the lower guide plate 34. The cutter 53b is arranged opposing to the guide groove 52b. The clamping member 54b is arranged opposing to the guide groove 51b.
The yarn shifting lever 35a is arranged between the untwisting pipe 41a and the upper guide plate 33 in the vertical direction. The yarn shifting lever 35b is arranged between the untwisting pipe 41b and the lower guide plate 34 in the vertical direction. The yarn shifting levers 35a and 35b are integrally formed, and by moving to the back side, push the yarns Y1 and Y2 guided to the yarn joining device 21 by the lower yarn catching / guiding member 23 and the upper yarn catching / guiding member 24. The yarns Y1 and Y2 pushed by the yarn shifting levers 35a and 35b are bent.
The twist stopping guide 36a is arranged between the untwisting pipe 41a and the yarn joining section 32 in the vertical direction. The twist stopping guide 36b is arranged between the untwisting pipe 41b and the yarn joining section 32 in the vertical direction. The twist stopping guide 36a and the twist stopping guide 36b are formed integrally. The twist stopping guides 36a and 36b are linked to the yarn shifting levers 35a and 35b, and are moveable along the yarn shifting levers 35a and 35b. However, a not-shown stopper that regulates the movement of the twist stopping guides 36a and 36b is provided in the yarn joining device 21, and in a state in which the movement of the twist stopping guides 36a and 36b is being regulated by the stopper, the yarn shifting levers 35a and 35b move but the twist

stopping guides 36a and 36b do not move. As explained later, when intertwining the cover fibers of the yarns Y1 and Y2 in the yarn joining section 32, the twist stopping guide 36a touches the yarn Y2 and the twist stopping guide 36b touches the yarn Y1. Accordingly, the twisting is prevented from being transmitted to a portion of the yarn Y2 present above the twist stopping guide 36a and a portion of the yarn Y1 present below the twist stopping guide 36b. Yarn Joining Section
Next, configuration of the yarn joining section 32 will be explained. As shown in FIGS. 4A to 6C, the yarn joining section 32 includes a yarn joining nozzle 61 and a nozzle block 62.
The yarn joining nozzle 61 is a substantially cube-shaped member having a length of approximately 12 millimeters (mm) on one side. The yarn joining nozzle 61 includes a yarn joining space 71, a yarn inserting gap 72, a first injection passage 73, a second injection passage 74, a third injection passage 75, an exhaust passage 76, a notch 77, and the like.
The yarn joining space 71 is formed at a substantially middle part of the yarn joining nozzle 61 in the front back direction ("second direction" in the present invention) and the left right direction ("third direction" in the present invention). The yarn joining space 71 passes through the yarn joining nozzle 61 in the vertical direction ("first direction" in the present invention). The yarn joining space 71 includes a first space 71a, a second space 71b, and a third space 71c.

The first space 71a forms an upper portion of the yarn joining space 71 that includes an upper end part thereof. The first space 71a is a circular space having a diameter of approximately 3 mm to 4 mm when seen from the vertical direction, and the length of the first space 71a is approximately 5 mm in the vertical direction. The second space 71b forms a lower portion of the yarn joining space 71 that includes a lower end part thereof. The second space 71b is a circular space having the same diameter as that of the first space 71a, and completely overlaps with the first space 71a. Moreover, similar to the first space 71a, the second space 71b, too, has a length of approximately 5 mm in the vertical direction.
The third space 71c forms a portion of the yarn joining space 71 that is positioned between the first space 71a and the second space 71b, and connects the first space 71a and the second space 71b. The third space 71c has a length of approximately 2 mm in the left right direction, which is shorter than the diameter of the first space 71a and the second space 71b, and overlaps with the middle portion of the first space 71a and the second space 71b in the left right direction. Accordingly, the length of a portion of the third space 71c located on a straight line parallel to the vertical direction that passes through a center T of the first space 71a and the second space 71b in the left right direction is shorter than the first space 71a and the second space 71b. Moreover, the third space 71c extends in the front back direction over the overall length of the first space 71a and the second

space 71b. Accordingly, the third space 71c extends till a groove bottom portion 71c1 that is an end portion located further on the back side (a side opposite to the yarn inserting gap 72) than the center T of the first space 71a and the second space 71b in the front back direction. Moreover, the groove bottom portion 71c1 is an arc-shaped circular end portion when the inner wall surface is seen in a plan view. Moreover, a portion of the third space 71c positioned between the grove bottom portion 71c1 and the yarn inserting gap 72 is a linear portion 71c2 that extends in the front back direction and has an inner wall surface parallel to the front back direction. The length of the third space 71c is approximately 2 mm in the vertical direction.
The yarn inserting gap 72 is formed on a substantially middle portion of a front end portion of the yarn joining nozzle 61 in the left right direction. The yarn inserting gap 72 passes through the yarn joining nozzle 61 in the vertical direction, and a rear end portion thereof is connected to a front end portion of the yarn joining space 71 and a front end portion thereof is open on a front end surface of the yarn joining nozzle 61. Accordingly, when the yarns Y1 and Y2 are guided to the yarn joining device 21 by the lower yarn catching / guiding member 23 and the upper yarn catching / guiding member 24, the yarns Y1 and Y2 are inserted to the yarn joining space 71 from the front side via the yarn inserting gap 72. The length of the yarn inserting gap 72 is approximately 2 mm in the left right direction, which is the same as the

length of the third space 71c in the left right direction.
A guiding surface 61a that is inclined in the left right direction toward the back side as one goes near the middle portion in the left right direction is arranged on the front end surface of the yarn joining nozzle 61. Accordingly, when the yarns Y1 and Y2 are guided to the yarn joining device 21 by the lower yarn catching / guiding member 23 and the upper yarn catching / guiding member 24, the yarns Y1 and Y2 are guided to the yarn inserting gap 72 by moving along the guiding surface 61a.
As shown in FIG. 6A, the first injection passage 73 includes a first injection port 73a having a diameter of approximately 1.4 mm that is open on an inner wall surface of the first space 71a of the yarn joining space 71 on immediate left side of the connecting portion between the first space 71a and the yarn inserting gap 72. The first injection passage 73 extends from the first injection port 73a in a tangential direction of the inner wall surface of the first space 71a when seen from the vertical direction. As shown in FIG. 6C, the second injection passage 74 includes a second injection port 74a having a diameter of approximately 1.4 mm that is open on an inner wall surface of the second space 71b of the yarn joining space 71 on immediate right side of the connecting portion between the second space 71b and the yarn inserting gap 72. The second injection passage 74 extends from the second injection port 74a in a tangential direction of the inner wall surface of the

second space 71b when seen from the vertical direction. Each of the tangential directions explained above may not be the same as a direction of the corresponding precise tangent of the inner wall surface, and may be arranged in a substantially same direction as the tangent. Specifically, the tangential direction can be a direction in which an air swirling current is generated respectively inside the first space 71a and the second space 71b.
As shown in FIG. 6B, the third injection passage 75 includes a third injection port 75a having a diameter of approximately 0.5 mm to 1 mm that is open on the inner wall surface of the linear portion 71c2 of the third space 71c of the yarn joining space 71 on the left side of the groove bottom portion 71c1 and further on the back side (a side opposite to the yarn inserting gap 72) than the center T of the first space 71a and the second space 71b. The third injection passage 75 extends toward the left side from the third injection port 75a. In other words, the third injection passage 75 extends from the third injection port 75a in a different direction than the direction in which the yarn inserting gap 72 is present. Moreover, the direction in which the third injection passage 75 extends also differs from a tangential direction (front back direction) of the inner wall surface of the third space 71c (linear portion 71c2) when seen from the vertical direction.
The exhaust passage 76 includes an exhaust port 76a having a diameter of approximately 1.2 mm to 1.5 mm that is open on the inner wall surface of the linear

portion 71c2 of the third space 71c of the yarn joining space 71 on the right side of the groove bottom portion 71c1 and further on the back side than the center T of the first space 71a and the second space 71b. Accordingly, the diameter (opening area) of the exhaust port 76a is larger than that of the third injection port 75a, and when seen from a left right direction in which the third injection passage 75 extends, the entire third injection port 75a overlaps with the exhaust port 76a. Moreover, the exhaust passage 76 extends from the exhaust port 76a toward the right side.
The notch 77 is formed over a left end surface, a right end surface, and a rear end surface of the yarn joining nozzle 61. More specifically, a portion of the notch 77 formed on the left end surface of the yarn joining nozzle 61 extends over substantially the entire area of the left end surface of the yarn joining nozzle 61 in the vertical and the left right directions. Moreover, an end portion of the first injection passage 73 positioned on a side opposite to the first injection port 73a and an end portion of the third injection passage 75 positioned on a side opposite to the third injection port 75a are open on a portion of the left end surface of the yarn joining nozzle 61 on which the notch 77 is formed.
Moreover, a portion of the notch 77 formed on the right end surface of the yarn joining nozzle 61 extends in a lower portion of the right end surface of the yarn joining nozzle 61 across substantially the entire length thereof in the front back direction. An end portion of the second injection passage 74 positioned

on a side opposite to the second injection port 74a is open on a portion of the right end surface of the yarn joining nozzle 61 on which the notch 77 is formed. An end portion of the exhaust passage 76 positioned on a side opposite to the exhaust port 76a is open on a portion positioned further above on the right end surface of the yarn joining nozzle 61 than a portion on which the notch 77 is formed. Moreover, a portion of the notch 77 formed on the rear end surface of the yarn joining nozzle 61 extends over the entire length of the rear end surface of the yarn joining nozzle 61 in the left right direction, and connects the portion of the notch 77 that is formed on the left end surface of the yarn joining nozzle 61 and the portion of the notch 77 that is formed on the right end surface of the yarn joining nozzle 61.
As shown in FIGS. 4A and 4B, the nozzle block 62 is a substantially rectangular-shaped member in which the front back direction is a longitudinal direction of the nozzle block 62, and includes a nozzle housing portion 81, an air supply flow path 82, and an atmosphere communication portion 83.
The nozzle housing portion 81 is arranged on a substantially middle portion of the nozzle block 62 in the left right direction, and an upper end part, a lower end part, and a front end part thereof are open. The nozzle housing portion 81 is a portion that houses the yarn joining nozzle 61, and when the yarn joining nozzle 61 is housed in the nozzle housing portion 81, the left end surface, the right end surface, and a front end surface of the yarn joining nozzle 61 are in

contact with a wall surface of the nozzle housing portion 81, and the notch 77 is covered by a portion of the nozzle block 62 that becomes a wall of the nozzle housing portion 81. A guiding surface 62a is formed on the front end surface of the nozzle block 62. When the yarn joining nozzle 61 is housed in the nozzle housing portion 81, the guiding surface 62a is positioned on the extension of the guiding surface 61a, and has an inclination in the left right direction toward the back side as one goes near the middle portion in the left right direction. Moreover, an angle of inclination of the guiding surface 62a and an angle of inclination of the guiding surface 61a in the left right direction are substantially the same. Accordingly, when the yarns Y1 and Y2 are guided to the yarn joining device 21 by the lower yarn catching / guiding member 23 and the upper yarn catching / guiding member 24, the yarns Y1 and Y2 are guided to the yarn inserting gap 72 by moving along the guiding surfaces 61a and 62a.
The air supply flow path 82 is formed on a portion of the nozzle block 62 that is arranged further on the left side than the nozzle housing portion 81. As shown in FIGS. 4B and 6B, the air supply flow path 82 extends in a slightly inclined direction in the left right direction, and a left end thereof is open on the left end surface of the nozzle block 62 and a right end thereof is open on the left side wall surface of the nozzle housing portion 81. Accordingly, when the yarn joining nozzle 61 is housed in the nozzle housing portion 81, the right end of the air supply flow path 82 is connected to the notch 77. The left end of the

air supply flow path 82 that is open on the left end surface of the nozzle block 62 is connected to a not-shown compressed air source. Accordingly, the compressed air is supplied to the notch 77 via the air supply flow path 82. Therefore, when the compressed air is supplied to the notch 77, the compressed air is injected inside the yarn joining space 71 from the first injection port 73a of the first injection passage 73, the second injection port 74a of the second injection passage 74, and the third injection port 75a of the third injection passage 75.
The atmosphere communication portion 83 is formed on a portion of the nozzle block 62 that is present on an immediate right side of the nozzle housing portion 81. An upper end of the atmosphere communication portion 83 is open on an upper surface of the nozzle block 62, and a left end thereof is connected to the nozzle housing portion 81. Accordingly, when the yarn joining nozzle 61 is housed in the nozzle housing portion 81, the atmosphere communication portion 83 is connected to the end portion of the exhaust passage 76 that is opposite to the exhaust port 76a, and the exhaust passage 76 communicates with the atmosphere via the atmosphere communication portion 83. Furthermore, in the vertical direction, the atmosphere communication portion 83 does not overlap with the portion of the notch 77 that is formed on the left end surface of the yarn joining nozzle 61. In other words, the atmosphere communication portion 83 is not connected to the notch 77. Yarn joining operation

A yarn joining operation performed by the yarn joining device 21 for joining the yarn Y1 and the yarn Y2 will be explained below. As explained above, when the yarn Y1 and the yarn Y2 are guided to the yarn joining device 21 by the lower yarn catching / guiding member 23 and the upper yarn catching / guiding member 24, the yarns Y1 and Y2 are introduced to the yarn joining space 71 via the yarn inserting gap 72. The yarn Y1 is also introduced to the guide grooves 51a and 52a. Similarly, the yarn Y2 is also introduced to the guide grooves 51b and 52b. In such a state, in the yarn joining device 21, as shown in FIG. 3A, the yarn shifting levers 35a and 35b move to the back side to push the yarns Y1 and Y2, and a portion of the yarns Y1 and Y2 present between the upper guide plate 33 and the yarn joining nozzle 61 and a portion of the yarns Y1 and Y2 present between the lower guide plate 34 and the yarn joining nozzle 61 are bent.
Subsequently, after the yarn Y1 introduced to the guide groove 51b is held by the clamping member 54b, the yarn Y1 introduced to the guide groove 51a is cut by the cutter 53a. Simultaneously, after the yarn Y2 introduced to the guide groove 52a is held by the clamping member 54a, the yarn Y2 introduced to the guide groove 52b is cut by the cutter 53b. When the yarns Y1 and Y2 are cut in such a manner, as shown in FIG. 3B, the yarn end of the cut yarn Y1 is sucked and introduced to the untwisting pipe 41a, and the yarn end of the cut yarn Y2 is sucked and introduced to the untwisting pipe 41b.

In the case that the yarn clearer 22 detects the yarn defect and the yarn Y is cut by the cutter 22a, the yarn defect still remains in the yarn Y2. However, when the yarn Y2 is cut by the cutter 53b, the yarn defect remaining in the yarn Y2 is removed.
Subsequently, the compressed air is injected from the injection hole 42 of the untwisting pipes 41a and 41b to generate the air current in the untwisting pipes 41a and 41b, thereby untwisting the cover fibers of the yarn ends of the yarns Y1 and Y2 respectively present inside the untwisting pipes 41a and 41b.
Subsequently, the yarn shifting levers 35a and 35b are moved further to the back side. When moved so, as shown in FIG. 3C, the untwisted yarn ends of the yarns Y1 and Y2 are respectively pulled from the untwisting pipes 41a and 41b, and further introduced to the yarn joining space 71. Then, by supplying the compressed air from the air supply flow path 82 to the notch 77 in a state in which the untwisted yarn ends of the yarns Y1 and Y2 are introduced to the yarn joining space 71, the compressed air is simultaneously injected from the first injection port 73a of the first injection passage 73, the second injection port 74a of the second injection passage 74, and the third injection port 75a of the third injection passage 75 inside the yarn joining space 71. Accordingly, the yarn Y1 and the yarn Y2 are joined. Therefore, by injecting the compressed air from the first injection port 73a of the first injection passage 73, the second injection port 74a of the second injection passage 74, and the third injection port 75a of the third injection passage 75 at

the same time, the yarn joining cycle can be made shortest. However, by adjusting the injection timing of the compressed air from respective injection ports depending on the type of yarn or an irregular outer appearance of the yarn at the time of the yarn joining, an appropriate yarn joining depending on the type of yarn and an excellent outer appearance can be prioritized.
More specifically, by injecting the compressed air from the first injection port 73a to the first space 71a in the tangential direction of the inner wall surface of the first space 71a when seen from the vertical direction and injecting the compressed air from the second injection port 74a to the second space 71b in the tangential direction of the inner wall surface of the second space 71b when seen from the vertical direction, the swirling current is generated in the yarn joining space 71 and the cover fibers of the yarn Y1 and the yarn Y2 are intertwined. Moreover, in such a state, the twist stopping guides 36a and 36b are respectively in contact with the yarns Y1 and Y2, and the intertwining of the cover fibers of the yarns Y1 and Y2 is prevented from transmitting to a portion of the yarn Y1 present below the twist stopping guide 36b and a portion of the yarn Y2 present above the twist stopping guide 36a.
Moreover, when the compressed air is injected from the third injection port 75a inside the third space 71c in a direction that moves from the left side to the right side, the core fibers of the yarns Y1 and Y2 present inside the third space 71c are blown off, and

repetitively stretched in the direction that moves from the left side to the right side by the action of the compressed air injected from the third injection port 75a and then shrink due to own elasticity. By such repetitive stretching and shrinking, tip end portions of the core fibers of the yarns Y1 and Y2 present inside the third space 71c are interlaced and joined.
At this stage, because the length of the third space 71c in the left right direction is shorter than that of the first space 71a and the second space 71b, the yarns Y1 and Y2 present inside the third space 71c are less likely to be separated when the compressed air is injected from the third injection port 75a. Accordingly, the tip end portions of the core fibers of the yarn Y1 and the yarn Y2 can be easily interlaced.
Moreover, in the present embodiment, the compressed air is injected from the third injection port 75a inside the third space 71c in the direction that moves from the left side to the right side, however, the direction in which the compressed air is injected is different from the direction that moves from the third injection port 75a towards the yarn inserting gap 72. Furthermore, the direction is perpendicular to the direction that moves from the yarn joining space 71 towards the yarn inserting gap 72 (front back direction). Accordingly, when the compressed air is injected from the third injection port 75a inside the third space 71c, the air current that flows from the yarn joining space 71 towards the yarn inserting gap 72 is less likely to be generated. As a result, when the compressed air is injected inside

the third space 71c from the third injection port 75a, the yarns Y1 and Y2 present inside the yarn joining space 71 can be prevented from flying out of the yarn joining space 71 via the yarn inserting gap 72.
In the present embodiment, the third injection port 75a of the third injection passage 75 is arranged facing the exhaust port 76a of the exhaust passage 76. Furthermore, the opening area of the exhaust port 76a is larger than the opening area of the third injection port 75a, and the entire third injection port 75a overlaps with the exhaust port 76a when seen from the left right direction. Accordingly, because the compressed air injected inside the third space 71c from the third injection port 75a is mainly discharged via the exhaust passage 76, the air current that flows from the yarn joining space 71 towards the yarn inserting gap 72 is less likely to be generated. Accordingly, when the compressed air is injected inside the third space 71c from the third injection port 75a, the yarns Y1 and Y2 present inside the yarn joining space 71 can be prevented more reliably from flying out of the yarn joining space 71 via the yarn inserting gap 72.
In the present embodiment, the third space 71c extends till the groove bottom portion 71c1 arranged further on the back side (the side opposite to the yarn inserting gap 72) than the center T of the first space 71a and the second space 71b, and the third injection port 75a is open on of the linear portion 71c2 further on the back side than the center T. Accordingly, the third injection port 75a is positioned away from the yarn inserting gap 72, and when the compressed air is

injected inside the third space 71c from the third injection port 75a, the yarns Y1 and Y2 present inside the yarn joining space 71 can be prevented more reliably from flying out of the yarn joining space 71 via the yarn inserting gap 72.
In the present embodiment, instead of the arc-shaped inner wall surface of the groove bottom portion (circular end portion) 71c1, the third injection port 75a is open on the inner wall surface of the linear portion 71c2 arranged parallel to the front back direction, and the compressed air is injected from the third injection port 75a in the direction parallel to the left right direction. Therefore, when the compressed air is injected from the third injection port 75a, the injected compressed air is less likely to collide with the arc-shaped inner wall surface of the groove bottom portion (circular end portion) 71c1. Accordingly, unnecessary swirling current can be prevented from generating in the third space 71c by the action of the compressed air injected from the third injection port 75a.
In the present embodiment, because the yarns Y1 and Y2 are bent by the movement of the yarn shifting levers 35a and 35b, the yarns Y1 and Y2 present inside the yarn joining space 71 are positioned at the rear end portion of the yarn joining space 71. Thus, when the third injection port 75a is arranged at a position explained above, the third injection port 75a overlaps with the yarns Y1 and Y2 present inside the third space 71c when seen from the left right direction in which the third injection passage 75 extends. Accordingly,

the compressed air injected from the third injection port 75a is directly injected onto the yarns Y1 and Y2 present inside the third space 71c, and the yarns Y1 and Y2 present inside the third space 71c are likely to be blown off by the compressed air injected from the third injection port 75a. As a result, stretching and shrinking of the core fibers of the yarns Y1 and Y2 explained above is likely to occur, and the tip end portions of the core fibers of the yarn Y1 and the yarn Y2 are likely to get interlaced.
Moreover, upon performing the operations explained above, when the yarn Y1 and the yarn Y2 are joined, the core fibers of the yarns Y1 and Y2 are joined and the cover fibers thereof are joined. Accordingly, a situation in which the portion of the yarn at which the yarn Y1 and the yarn Y2 are joined does not have the core fibers can be prevented. Moreover, because the end portions of the core fibers of the yarns Y1 and Y2 are interlaced and joined, the tip end portion of the core fiber of the yarn Y1 does not protrude further upward than the portion at which the yarn Y1 and the yarn Y2 are joined and in a direction different than a longitudinal direction of the yarn, and the tip end portion of the core fibers of the yarn Y2 does not protrude further downward than the portion at which the yarn Y1 and the yarn Y2 are joined and in a direction different than the longitudinal direction of the yarn. Moreover, after the yarn joining is performed as explained above, the yarn shifting levers 35a and 35b and the twist stopping guides 36a and 36b are returned to the initial positions away from the yarn Y, and

winding operation performed in the winding section 13 is resumed.
Exemplary embodiments of the present invention are explained above. However, the present invention is not limited to the embodiments explained above. Various changes or modifications are possible as long as the changes and the modifications fairly fall within the scope of the patent claims.
In the above embodiments, the third injection port 75a overlaps with the yarns Y1 and Y2 that are introduced to the third space 71c when seen from the left right direction in which the third injection passage 75 extends. The present invention, however, is not limited to such a configuration, and the third injection port 75a may not overlap with the yarns Y1 and Y2 that are introduced to the third space 71c when seen from the left right direction in which the third injection passage 75 extends.
In the above embodiments, the third injection port 75a is open on the inner wall surface of the linear portion 71c2 of the third space 71c further on the back side than the center T of the first space 71a and the second space 71b. The present invention, however, is not limited to such a configuration. For example, the third injection port 75a can be open on the arc-shaped inner wall surface of the groove bottom portion (circular end portion) 71c1 of the third space 71c.
Furthermore, in the front back direction, the third injection port 75a can be open on the inner wall surface of the third space 71c at a position as same as the center T of the first space 71a and the second

space 71b, or can be open on the inner wall surface of the third space 71c further on the front side than the center T (on the yarn inserting gap 72 side). Moreover, in such a configuration, a configuration of the third space 71c is not limited to extending toward further on the back side than the center T, and the third space 71c can at least extend up to a position at which the third injection port 75a is open.
In the above embodiments, the length of the third space 71c is shorter in the left right direction than that of the first space 71a and the second space 71b. The present invention, however, is not limited to such a configuration, and, for example, the third space 71c can be formed in the same circular shape as the first space 71a and the second space 71b when seen from the vertical direction, and can entirely overlap with the first space 71a and the second space 71b.
In the above embodiments, the first space 71a and the second space 71b have the same shape when seen from the vertical direction, and entirely overlap with each other. The present invention, however, is not limited to such a configuration, and, for example, the first space 71a and the second space 71b can be positioned by deviating from each other in the left right direction, and can partially overlap with each other when seen from the vertical direction. Alternatively, the first space 71a and the second space 71b can be formed in different shapes when seen from the vertical direction.
In the above embodiments, the third injection passage 75 extends in the left right direction from the third injection port 75a. The present invention,

however, is not limited to such a configuration, and the third injection passage 75 can extend from the third injection port 75a in a direction that is different than the direction that moves towards the yarn inserting gap 72.
In the above embodiments, the opening area of the exhaust port 76a is larger than the opening area of the third injection port 75a, and the entire third injection port 75a overlaps with the exhaust port 76a when seen from the left right direction in which the third injection passage 75 extends. The present invention, however, is not limited to such a configuration, and only a part of the third injection port 75a can overlap with the exhaust port 76a. In such a case, the opening area of the exhaust port 76a can be smaller than or equal to the opening area of the third injection port 75a. Moreover, the exhaust port 76a of the exhaust passage 76 may not be arranged facing the third injection port 75a. Furthermore, the exhaust passage 76 may not be provided in the yarn joining nozzle 61. Alternatively, a plurality of the third injection ports 75a can be provided. In such a case, a plurality of the exhaust ports 76a can be also provided, or a configuration in which the compressed air injected from the plurality of the third injection ports 75a flows to a single exhaust port 76a can be provided.
Exemplary configuration in which the present invention is applied to the winding unit of the automatic winder has been explained above. However, the present invention is not limited to such a

configuration, and can also be applied to a yarn winding device that includes a spinning device, a plurality of work carts, and the like.
According to one aspect of the present invention, a yarn joining nozzle includes a yarn joining space that extends in a first direction; a yarn inserting gap that extends in the first direction and communicates with the yarn joining space in a second direction that is perpendicular to the first direction, and via which a yarn is inserted into the yarn joining space by moving the yarn in the second direction; and a plurality of injection passages via which compressed air is injected inside the yarn joining space. The yarn joining space includes a first space that is circular when seen from the first direction; a second space arranged away from the first space in the first direction, and is circular when seen from the first direction; and a third space that is positioned between the first space and the second space in the first direction. The plurality of the injection passages includes a first injection passage that includes a first injection port that is open on an inner wall surface of the first space, and extends from the first injection port in a tangential direction of the inner wall surface of the first space when seen from the first direction; a second injection passage that includes a second injection port that is open on an inner wall surface of the second space, and extends from the second injection port in a tangential direction of the inner wall surface of the second space when seen from the first direction; and a third

injection passage that includes a third injection port that is open on an inner wall surface of the third space, and extends from the third injection port toward a direction that is different from a direction in which the yarn inserting gap is present.
In the present invention, in a state in which two yarns of which elastic core fibers are covered by cover fibers are positioned inside the yarn joining space, when the compressed air is injected from the first injection port and the second injection port in the corresponding tangential direction of the inner wall surface of the yarn joining space when seen from the first direction, a swirling current is generated inside the yarn joining space and the cover fibers of the two yarns are intertwined. Moreover, in the present invention, when the compressed air is injected from the third injection port positioned between the first injection port and the second injection port, the core fibers of the two yarns are blown off, and repetitively stretched by the action of the compressed air injected from the third injection port and then shrink due to own elasticity. By such repetitive stretching and shrinking, tip end portions of the core fibers of the two yarns are interlaced. Accordingly, the core fibers and cover fibers of the two yarns can be joined.
In the present invention, because the compressed air is injected from the third injection port in the direction different from the direction in which the yarn inserting gap is present, when the compressed air is injected from the third injection port inside the yarn joining space, an air current that flows from the

yarn joining space toward the yarn inserting gap is less likely to be generated. Accordingly, when the compressed air is injected from the third injection port inside the yarn joining space, the yarns present inside the yarn joining space can be prevented from flying out of the yarn joining space via the yarn inserting gap.
The above yarn joining nozzle further includes an exhaust passage that includes an exhaust port that is open on a portion of an inner wall surface of the third space that faces the third injection port.
In the present invention, because the compressed air injected from the third injection port is mainly discharged via the exhaust passage, when the compressed air is injected from the third injection port inside the yarn joining space, the air current that flows from the yarn joining space toward the yarn inserting gap is less likely to be generated. Accordingly, when the compressed air is injected from the third injection port inside the yarn joining space, the yarns present inside the yarn joining space can be prevented more reliably from flying out of the yarn joining space via the yarn inserting gap.
In the above yarn joining nozzle, an opening area in the third space of the exhaust port is larger than an opening area in the third space of the third injection port, and the entire third injection port overlaps with the exhaust port when seen from a direction in which the third injection passage extends.
In the present invention, because the entire third injection port overlaps with the exhaust port when seen

from the direction in which the third injection passage extends, the compressed air injected from the third injection port is likely to be discharged via the exhaust passage. Therefore, when the compressed air is injected from the third injection port inside the yarn joining space, the air current that flows from the yarn joining space toward the yarn inserting gap is less likely to be generated. As a result, when the compressed air is injected from the third injection port inside the yarn joining space, the yarns present inside the yarn joining space can be prevented more reliably from flying out of the yarn joining space via the yarn inserting gap.
In the above yarn joining nozzle, the third injection passage extends from the third injection port toward a third direction that is perpendicular to the first direction and the second direction.
In the present invention, because a direction in which the compressed air is injected from the third injection port (third direction) is perpendicular to the direction that moves from the yarn joining space toward the yarn inserting gap (second direction), when the compressed air is injected from the third injection port inside the yarn joining space, the air current that flows from the yarn joining space toward the yarn inserting gap is less likely to be generated. As a result, when the compressed air is injected from the third injection port inside the yarn joining space, the yarns present inside the yarn joining space can be prevented more reliably from flying out of the yarn joining space via the yarn inserting gap.

In the above yarn joining nozzle, a length of a portion of the third space positioned on a straight line that passes through a center of the first space and the second space is shorter in the third direction than that of the first space and the second space.
In the present invention, because the third injection port is open on the inner wall surface of the third space that has shorter length in the third direction, when the compressed air is injected from the third injection port in the third direction, the core fibers of the two yarns inside the third space are less likely to be separated, and the tip end portions of the core fibers of the two yarns can be easily interlaced.
In the above yarn joining nozzle, in the second direction, the third space extends till a groove bottom portion positioned on an opposite side of the yarn inserting gap with respect to the center of the first space and the second space. The third injection port is open on the inner wall surface of the third space at a position between the center of the first space and the second space and the groove bottom portion in the second direction.
Because the third injection port is open on the inner wall surface of the third space at a position between the center of the first space and the second space and the groove bottom portion positioned on the opposite side of the yarn inserting gap (a portion located away from the yarn inserting gap) in the second direction, when the compressed air is injected from the third injection port, the yarn present inside the yarn joining space can be prevented more reliably from

flying out of the yarn joining space via the yarn inserting gap.
In the above yarn joining nozzle, the groove bottom portion is a circular end portion having an inner wall surface formed in an arc shape when seen from the first direction. The third space extends in the second direction between the circular end portion and the yarn inserting gap, and includes a linear portion having an inner wall surface that is parallel to the second direction. The third injection port is open on the inner wall surface of the linear portion.
In the present invention, because the inner wall surface of the groove bottom portion is arc-shaped when seen from the first direction, when the swirling current is generated inside the yarn joining space by the action of the compressed air injected from the first injection port and the second injection port, the yarn present inside the third space smoothly moves along the inner wall surface of the circular end portion. Moreover, because the third injection port is open on the inner wall surface of the linear portion extends in the second direction, when the compressed air is injected from the third injection port in the third direction, it is less likely that the injected compressed air collides on the inner wall surface of the circular end portion, and unnecessary swirling current generated by the action of the compressed air injected from the third injection port can be prevented from generating inside the yarn joining space.
In the above yarn joining nozzle, when seen from the direction in which the third injection passage

extends, the third injection port opens on a portion of the inner wall surface of the third space that overlaps with the yarn introduced to the yarn joining space.
In the present invention, because the compressed air is directly injected from the third injection port on the yarn present in the third space, the yarn can be easily blown by the compressed air injected from the third injection port and the tip end portions of the core fibers of the two yarns can be reliably interlaced.
According to another aspect of the present invention, a yarn joining device includes the above yarn joining nozzle.
According to still another aspect of the present invention, a yarn winding device includes a yarn supplying section capable of supplying a yarn; a winding section that is arranged at a position away from the yarn supplying section in the first direction and winds the yarn supplied from the yarn supplying section; and the above yarn joining device that is arranged between the yarn supplying section and the winding section in the first direction.
According to still another aspect of the present invention, a yarn joining method is a yarn joining method for joining inside a yarn joining nozzle two yarns, in which elastic core fibers are covered with cover fibers. The yarn joining nozzle includes a yarn joining space that extends in a first direction; and a yarn inserting gap that extends in the first direction and communicates with the yarn joining space in a second direction that is perpendicular to the first direction, and via which a yarn is inserted into the

yarn joining space by moving the yarn in the second direction. The yarn joining space includes a first space that is circular when seen from the first direction; a second space that is arranged away from the first space in the first direction, and is circular when seen from the first direction; and a third space that is positioned between the first space and the second space in the first direction. The yarn joining method includes generating a swirling current inside the yarn joining space by injecting compressed air inside the first space in a tangential direction of an inner wall surface of the first space as seen from the first direction and inside the second space in a tangential direction of an inner wall surface of the second space as seen from the first direction to intertwine the cover fibers of the two yarns; and injecting the compressed air inside the third space in a direction different from a direction in which the yarn inserting gap is present to interlace the core fibers of the two yarns.
In the present invention, the core fibers and the cover fibers of the two yarns can be joined. Moreover, by the action of the compressed air injected from the third injection port, the yarn present inside the yarn joining space can be prevented from flying out of the yarn joining space via the yarn inserting gap.
In the above explanation, the meaning of "a plurality of" also includes "a predetermined number of".
Although the invention has been explained 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 scope of the claims.

We claim:
1. A yarn joining nozzle (61) comprising:
a yarn joining space (71) that extends in a first direction;
a yarn inserting gap (72) that extends in the first direction and communicates with the yarn joining space (71) in a second direction that is perpendicular to the first direction, and via which a yarn is inserted into the yarn joining space (71) by moving the yarn in the second direction; and
a plurality of injection passages (73, 74, 75) via which compressed air is injected inside the yarn joining space (71), wherein
the yarn joining space (71) includes,
a first space (71a) that is circular when seen from the first direction;
a second space (71b) arranged away from the first space (71a) in the first direction, and is circular when seen from the first direction; and
a third space (71c) that is positioned between the first space (71a) and the second space (71b) in the first direction, and
the plurality of the injection passages (73, 74, 75) includes,
a first injection passage (73) that includes a first injection port (73a) that is open on an inner wall surface of the first space (71a), and extends from the first injection port (73a) in a tangential direction of the inner wall surface of the first space (71a) when seen from the first direction;

a second injection passage (74) that includes a second injection port (74a) that is open on an inner wall surface of the second space (71b), and extends from the second injection port (74a) in a tangential direction of the inner wall surface of the second space (71b) when seen from the first direction; and
a third injection passage (75) that includes a third injection port (75a) that is open on an inner wall surface of the third space (71c), and extends from the third injection port (75a) toward a direction that is different from a direction in which the yarn inserting gap (72) is present.
2. The yarn joining nozzle (61) as claimed in Claim 1
further comprising an exhaust passage (76) that
includes an exhaust port (76a) that is open on a
portion of an inner wall surface of the third space
(71c) that faces the third injection port (75a).
3. The yarn joining nozzle (61) as claimed in Claim 2,
wherein an opening area in the third space (71c) of the
exhaust port (76a) is larger than an opening area in
the third space (71c) of the third injection port (75a),
and the entire third injection port (75a) overlaps with
the exhaust port (76a) when seen from a direction in
which the third injection passage (75) extends.
4. The yarn joining nozzle (61) as claimed in any one
of Claims 1 to 3, wherein the third injection passage
(75) extends from the third injection port (75a) toward

a third direction that is perpendicular to the first direction and the second direction.
5. The yarn joining nozzle (61) as claimed in Claim 4, wherein a length of a portion of the third space (71c) positioned on a straight line that passes through a center of the first space (71a) and the second space (71b) is shorter in the third direction than that of the first space (71a) and the second space (71b).
6. The yarn joining nozzle (61) as claimed in Claim 5, wherein
in the second direction, the third space (71c) extends till a groove bottom portion (71c1) positioned on an opposite side of the yarn inserting gap (72) with respect to the center of the first space (71a) and the second space (71b), and
the third injection port (75a) is open on the inner wall surface of the third space (71c) at a position between the center of the first space (71a) and the second space (71b) and the groove bottom portion (71c1) in the second direction.
7. The yarn joining nozzle (61) as claimed in Claim 6,
wherein
the groove bottom portion (71c1) is a circular end portion (71c1) having an inner wall surface formed in an arc shape when seen from the first direction,
the third space (71c) extends in the second direction between the circular end portion (71c1) and the yarn inserting gap (72), and includes a linear

portion (71c2) having an inner wall surface that is parallel to the second direction, and
the third injection port (75a) is open on the inner wall surface of the linear portion (71c2).
8. The yarn joining nozzle (61) as claimed in any one of Claims 1 to 7, wherein, when seen from the direction in which the third injection passage (75) extends, the third injection port (75a) opens on a portion of the inner wall surface of the third space (71c) that overlaps with the yarn introduced to the yarn joining space (71).
9. A yarn joining device (21) comprising the yarn joining nozzle (61) as claimed in any one of Claims 1 to 8.
10. A yarn winding device (2) comprising:
a yarn supplying section (11) capable of supplying a yarn;
a winding section (13) that is arranged at a position away from the yarn supplying section (11) in the first direction and winds the yarn supplied from the yarn supplying section (11); and
the yarn joining device (21) as claimed in Claim 9 that is arranged between the yarn supplying section (11) and the winding section (13) in the first direction.

11. A yarn joining method for joining inside a yarn joining nozzle (61) two yarns, in which elastic core fibers are covered with cover fibers, wherein the yarn joining nozzle (61) includes
a yarn joining space (71) that extends in a first direction; and
a yarn inserting gap (72) that extends in the first direction and communicates with the yarn joining space (71) in a second direction that is perpendicular to the first direction, and via which a yarn is inserted into the yarn joining space (71) by moving the yarn in the second direction, and
the yarn joining space (71) includes
a first space (71a) that is circular when seen from the first direction;
a second space (71b) that is arranged away from the first space (71a) in the first direction, and is circular when seen from the first direction; and
a third space (71c) that is positioned between the first space (71a) and the second space (71b) in the first direction, the yarn joining method comprising
generating a swirling current inside the yarn joining space (71) by injecting compressed air inside the first space (71a) in a tangential direction of an inner wall surface of the first space (71a) as seen from the first direction and inside the second space (71b) in a tangential direction of an inner wall surface of the second space (71b) as seen from the first direction to intertwine the cover fibers of the two yarns; and

injecting the compressed air inside the third
space (71c) in a direction different from a direction
in which the yarn inserting gap (72) is present to
interlace the core fibers of the two yarns.