Patent Description:
Patent Literature <NUM> discloses a yarn winder according to the preamble of claim <NUM> and describes a yarn winder which is configured to unwind a yarn from a yarn supply package and to wind the yarn onto a winding bobbin so as to form a wound package. To be more specific, the yarn winder includes a motor which is configured to rotationally drive the yarn supply package and a guide roller (direction changing unit) which is provided outside the yarn supply package in the radial direction of the yarn supply package. The rotational shaft of the yarn supply package extends in the vertical direction. The winding bobbin is provided above the yarn supply package (outside the yarn supply package in the axial direction of the yarn supply package). In the yarn winder structured as described above, as the yarn supply package is rotationally driven, the yarn is unwound from the yarn supply package. Then, the yarn is guided upward (toward the wound package) by the direction changing unit.

In terms of aspects such as the suppression of occurrence of yarn breakage, it is required to maintain the tension of the yarn to be constant. However, the tension of the yarn may frequently vary because, for example, a yarn path from the yarn supply package to the wound package varies in accordance with traversing of the unwound yarn, etc. To solve this problem, the above-described direction changing unit is passively movable in the radial direction (horizontal direction) of the yarn supply package, and is biased by a spring. Because of this, the direction changing unit is moved by the variation in the distance of the yarn path so that the excessive tension of the yarn or the slack of the yarn is suppressed. As a result, the variation in tension is also suppressed.

In a yarn winder recited in Patent Literature <NUM>, a direction changing unit is passively moved in a direction orthogonal to a guide direction in which a yarn is guided by the direction changing unit. Therefore, problems such as the following problem may occur. That is, because a yarn running downstream of the direction changing unit in a yarn running direction is easily and significantly moved in the horizontal direction (i.e., is easily swung in the horizontal direction), a yarn path easily varies. Because of this, when a member is provided in the vicinity of the yarn path, the member may interfere with the yarn. In order to avoid the interference described above, there is a need of ensuring a wide space around the yarn path. This may result in increase of the size of the apparatus.

An object of the present invention is to suppress the variation of a yarn path due to the passive movement of a direction changing unit.

A first aspect of the present invention provides a yarn winder in accordance with claim <NUM> and configured to form a wound package by unwinding a yarn from a yarn supply package which is rotating and by winding the yarn onto a winding bobbin which is provided at least on one side of the yarn supply package in an axial direction of the yarn supply package, the yarn winder including a direction changing unit which is provided outside the yarn supply package in a radial direction of the yarn supply package and which is configured to guide the yarn to one side in a guide direction having a component in the axial direction, the direction changing unit being configured to be freely movable in a moving direction, the moving direction and the guide direction forming an angle which is <NUM> degrees or less, and a predetermined power being applied to the direction changing unit at least toward the other side in the guide direction.

In the present invention, to begin with, the yarn having been unwound from the yarn supply package is guided toward the one side in the guide direction by direction changing unit. To the direction changing unit, power is applied at least toward the other side in the guide direction. The yarn is always pulled by this direction changing unit. Because of this, a predetermined tension is applied to the yarn. Because the direction changing unit is freely movable, the variation in the tension of the yarn is suppressed as follows. For example, when the winding speed of the yarn is relatively fast as compared to the unwinding speed of the yarn, the direction changing unit is pulled to the one side in the guide direction by the yarn and passively moved. A yarn path is therefore short, and hence excessive tension of the yarn due to the difference between the relative speeds is suppressed. Meanwhile, when the winding speed of the yarn is relatively slow, the yarn is about to slacken. However, because power is applied to the direction changing unit as described above, the direction changing unit pulls the yarn Y while passively moving toward the other side in the guide direction. The yarn path is therefore long, and hence the slack of the yarn due to the difference between the relative speeds is suppressed.

In the present invention, an angle formed between the moving direction of the direction changing unit and the guide direction is <NUM> degrees or less. Because of this, as compared to a structure in which the moving direction and the guide direction are orthogonal to or substantially orthogonal to each other, the large swing (variation of the yarn path) of the yarn due to the passive movement of the direction changing unit is suppressed. In this regard, the yarn runs downstream of the direction changing unit in the yarn running direction. Therefore, the variation of the yarn path due to the passive movement of the direction changing unit is suppressed.

According to the first aspect of the invention, the yarn winder further includes: an unwinding driving unit configured to rotationally drive the yarn supply package; a winding driving unit configured to rotationally drive the wound package; a position detection unit configured to detect a position of the direction changing unit in the moving direction; and a controller configured to control at least one of the unwinding driving unit and the winding driving unit based on a detection result provided by the position detection unit.

For example, when the diameter of the yarn supply package is gradually decreased as the unwinding of the yarn advances in a state in which the rotation speed of the yarn supply package is constant, the winding speed of the yarn is relatively increased because the unwinding speed of the yarn is decreased. Therefore, the direction changing unit may be pulled toward one side in the guide direction and may significantly move. In this regard, when the direction changing unit moves outward of the end face of the yarn supply package in the axial direction, the yarn may drop off from the end face of the yarn supply package and may not be able to properly run. In the present invention, the controller is configured to control at least one of the unwinding driving unit and the winding driving unit based on the detection result provided by the position detection unit. With this arrangement, by actively changing the difference between the winding speed of the yarn and the unwinding speed of the yarn, it is possible to actively move the direction changing unit. Because of this, the position of the direction changing unit is controlled. For example, the feedback control is performed to move the position of the direction changing unit close to the target position. It is therefore possible to suppress the large movement of the direction changing unit.

According to a second aspect of the invention, the yarn winder of the first aspect is arranged such that the controller is configured to control the unwinding driving unit based on the detection result provided by the position detection unit.

According to a third aspect of the invention, the yarn winder of the first or second aspect is arranged such that the position detection unit is an optical sensor configured to optically detect the position of the direction changing unit in the moving direction.

For example, in a structure in which a magnetic sensor is used to magnetically detect the position of the direction changing unit, the direction changing unit is required to be formed of a conductor made of metal, etc. or to have such a conductor thereon. Therefore, the mass of the direction changing unit may be increased to obstruct the passive movement of direction changing guide. For example, in a structure in which a contact type position sensor is used, the sensor is easily worn away because the direction changing unit frequently moves. This may lead to an early deterioration of the sensor. In the present invention, because the position of the direction changing unit is optically detected, the increase in the mass of the direction changing unit and the early deterioration of the position detection unit, etc., are suppressed.

According to a fourth aspect of the invention, the yarn winder of any one of the first to third aspects further includes a separation unit which is provided between the yarn supply package and the direction changing unit in a yarn running direction and which is provided outside the yarn supply package in the radial direction, and the separation unit is configured to be passively movable in the axial direction, and/or a contact part of the separation unit making contact with the yarn extends in the axial direction.

The yarn having been unwound from the rotating yarn supply package runs toward the direction changing unit while being traversed in the axial direction of the yarn supply package about the direction changing unit. At this stage, when a traverse angle at which the yarn is traversed about the direction changing unit is large, the yarn path from the surface of the yarn supply package to the direction changing unit significantly varies during the traversing of the yarn. However, when the direction changing unit is provided to be apart from the yarn supply package so that the traverse angle is small, size of the device is disadvantageously increased. In the present invention, the yarn having been unwound from the yarn supply package runs toward the direction changing unit via the separation unit. Because of this, even when the direction changing unit is not set apart from the yarn supply package, the yarn path from the surface of the yarn supply package to the direction changing unit is long. Because the separation unit is passively movable and/or the contact part of the separation unit making contact with the yarn extends in the axial direction, the yarn is smoothly slid in the axial direction. Therefore, the traverse angle of the unwound yarn is arranged to be small while increase in size of a device is suppressed.

According to a fifth aspect of the invention, the yarn winder of any of the first to fourth aspects is arranged such that the moving direction has a component in the vertical direction, and the predetermined power is the gravity.

In the present invention, the direction changing unit moves by means of the gravity. It is therefore possible to simplify the structure and to reduce the cost as compared to a structure in which power is applied to the direction changing unit by, e.g. , a spring. Furthermore, because the stable power provided by the gravity is applied to the direction changing unit, the running yarn is stably pulled. Because of this, tension is stably applied to the running yarn.

According to a sixth aspect of the invention, the yarn winder of any of the first to fifth aspects further includes a rail member which extends in the moving direction and which is formed to allow the direction changing unit to be freely movable.

For example, in a structure in which a typical dancer roller connected to a swing type dancer arm is used as the direction changing unit, the structure of a member configured to be passively moved is complex so that the mass (inertial mass) of the member configured to be passively moved is large, and hence the followability of the direction changing unit is deteriorated. In the present invention, because it is possible to cause only the direction changing unit to be passively moved along the rail member, the structure of the member configured to be passively moved is simplified. As a result, the inertial mass of this member is decreased. Therefore, the followability of the direction changing unit is increased.

According to a seventh aspect of the invention, the yarn winder of any one of the first to sixth aspects is arranged such that the moving direction is parallel to the axial direction.

If the moving direction is tilted with respect to the axial direction of the yarn supply package, the direction changing unit moves so that a distance between the direction changing unit and the surface of the yarn supply package varies. As a result, the length of the yarn path varies. In the present invention, because the moving direction is parallel to the axial direction, the variation in length of such a yarn path is suppressed.

According to an eighth aspect of the invention, the yarn winder of any one of the first to seventh aspects is arranged such that the axial direction is parallel to the vertical direction.

For example, when the yarn supply package is horizontally provided so that the axial direction of the yarn supply package is parallel to the horizontal direction, the rotational shaft of the yarn supply package may be warped downward by the effect of the gravity so that the rotation of the yarn supply package is unstable. In the present invention, the axial direction of the yarn supply package is parallel to the vertical direction. Therefore, the warping of the rotational shaft due to the gravity is prevented. It is therefore possible to suppress the rotation of the yarn supply package from becoming unstable.

According to a ninth aspect of the invention, the yarn winder of any one of the first to eighth aspects further includes a yarn feed roller which is provided downstream of the direction changing unit in the yarn running direction.

In a structure in which the yarn feed roller sends the yarn further toward the downstream side in the yarn running direction, when the yarn is slackened immediately upstream of the yarn feed roller in the yarn running direction, the yarn may slip on the circumferential surface of the yarn feed roller and may not be able to properly run. In the present invention, because the yarn is always pulled toward the other side (i.e., upstream side) in the guide direction by the direction changing unit, it is possible to suppress the yarn from being slackened on the upstream side of the yarn feed roller in the yarn running direction.

According to a tenth aspect of the invention, the yarn winder of any one of the first to ninth aspects further includes:
a package supporting portion which rotatably supports the yarn supply package; and a base which vertically extends on one side of the package supporting portion in an intersecting direction intersecting with the vertical direction, wherein the package supporting portion is movable between an unwinding position where the yarn is unwound from the yarn supply package and a replacement position which is at least on the other side in the intersecting direction of the unwinding position.

Typically, yarn winders each of which is like the above-described yarn winder are often aligned in the horizontal direction. In addition to that, in each yarn winder, a working space which is used at the time of the replacement of the yarn supply package is typically provided on the other side in the intersecting direction of the base. Provided that the package supporting portion is immovable in this structure, when the yarn winders are aligned, it may be difficult to ensure a space for the replacement of the yarn supply package in each yarn winder. In the present invention, at least in the intersecting direction, because the package supporting portion is moved to the replacement position which is far (i.e., on the working space side) from the base as compared to the unwinding position, a wide space for the replacement is ensured. It is therefore possible to facilitate the replacement of the yarn supply package.

The following will describe an embodiment of the present invention with reference to <FIG>. An up-down direction and a left-right direction shown in <FIG> will be referred to as an up-down direction (vertical direction in which the gravity acts) and a left-right direction of a re-winder <NUM>. A front-rear direction shown in <FIG> will be referred to as a front-rear direction of the re-winder <NUM>. A direction in which a yarn Y runs will be referred to as a yarn running direction.

To begin with, the structure of the re-winder <NUM> (yarn winder of the present invention) of the present embodiment will be described with reference to <FIG> is a schematic diagram of the re-winder <NUM>. As shown in <FIG>, the re-winder <NUM> includes members such as a yarn supplying unit <NUM>, a winding unit <NUM>, and a controller <NUM> (control unit of the present invention). The re-winder <NUM> is configured to unwind a yarn Y from a yarn supply package Ps supported by the yarn supplying unit <NUM> and to wind the yarn Y onto a winding bobbin Bw by means of the winding unit <NUM>, so as to form a wound package Pw. To be more specific, the re-winder <NUM> is used for, for example, re-winding a yarn Y wound on a yarn supply package Ps in a more beautiful manner, and for forming a wound package Pw with desired density.

The yarn supplying unit <NUM> is configured to rotationally drive a yarn supply package Ps formed by winding a yarn Y onto the yarn supplying bobbin Bs, so as to unwind the yarn Y from the yarn supply package Ps. The yarn supplying unit <NUM> is provided (see <FIG>) in front of a lower portion of a base <NUM> which vertically extends. The yarn supplying unit <NUM> mainly includes a supporting table <NUM>, an unwinding motor <NUM> (unwinding driving unit of the present invention), a direction changing guide <NUM> (direction changing unit of the present invention), and a yarn guide <NUM>. The yarn supplying unit <NUM> unwinds the yarn Y in such a way that the unwinding motor <NUM> rotationally drives the yarn supply package Ps supported to be rotatable by the supporting table <NUM>, and guides the yarn Y toward the downstream side in the yarn running direction via the direction changing guide <NUM> and the yarn guide <NUM>.

This supporting table <NUM> is a table fixed to a front surface of the lower portion of the base <NUM>. The supporting table <NUM> rotatably supports the yarn supply package Ps so that an axial direction of the yarn supply package Ps is parallel to the up-down direction. The unwinding motor <NUM> rotationally drives the yarn supply package Ps in a direction in which the yarn Y is unwound. The unwinding motor <NUM> is, e.g., a typical AC motor in which the rotation number is variable. Because of this, the unwinding motor <NUM> is able to change the rotation speed of the yarn supply package Ps. The unwinding motor <NUM> is electrically connected to the controller <NUM>. The direction changing guide <NUM> is configured so that the yarn Y having been unwound from the yarn supply package Ps is guided upward. The direction changing guide <NUM> is provided outside the yarn supply package Ps in a radial direction of the yarn supply package Ps. The yarn guide <NUM> is configured to guide the yarn Y having been guided by the direction changing guide <NUM> further toward the downstream side in the yarn running direction. The yarn guide <NUM> is provided immediately above, e.g., the direction changing guide <NUM>.

The winding unit <NUM> is provided at an upper portion (i.e., at least above the yarn supplying unit <NUM>; in other words, at least on one side of the yarn supply package Ps in the axial direction of the yarn supply package Ps) of the base <NUM>. The winding unit <NUM> includes members such as a cradle arm <NUM>, a winding motor <NUM> (winding driving unit of the present invention), and a traverse guide <NUM>. In the winding unit <NUM>, the winding motor <NUM> rotationally drives the winding bobbin Bw supported to be rotatable by the cradle arm <NUM> while the traverse guide <NUM> traverses the yarn Y, so that the winding unit <NUM> winds the yarn Y onto the winding bobbin Bw. For example, a cheese package is formed (see <FIG>) by winding the yarn Y onto a cylindrical winding bobbin Bw.

The cradle arm <NUM> supports the winding bobbin Bw to be rotatable. The cradle arm <NUM> is supported at the upper portion of the base <NUM>. To the cradle arm <NUM>, a bobbin holder (not illustrated) is attached to be rotatable and to hold the winding bobbin Bw. The bobbin holder supports the winding bobbin Bw so that the rotational shaft of the winding bobbin Bw extends in the left-right direction (i.e., direction intersecting with the axial direction of the yarn supply package Ps). The winding motor <NUM> rotationally drives the bobbin holder so that the winding bobbin Bw (wound package Pw) is rotated. The winding motor <NUM> is, for example, a typical AC motor in which the rotation number is variable. The winding motor <NUM> is therefore able to change the rotation speed of the winding bobbin Bw. The winding motor <NUM> is electrically connected to the controller <NUM>. The traverse guide <NUM> is reciprocated in an axial direction of the winding bobbin Bw by an unillustrated driving device, and traverses the yarn Y running toward the winding bobbin Bw. A contact roller <NUM> is provided downstream of the traverse guide <NUM> in the yarn running direction. The contact roller <NUM> applies a contact pressure to the surface of the wound package Pw to adjust the shape of the wound package Pw.

In the yarn running direction, a yarn guide <NUM> and a tension sensor <NUM> are provided between the yarn supplying unit <NUM> and the winding unit <NUM>. The yarn guide <NUM> is provided downstream of the yarn guide <NUM> in the yarn running direction, and provided on an extension of the rotational shaft of the yarn supply package Ps. By the yarn guide <NUM>, the yarn Y is guided upward. The sensor <NUM> is provided between the yarn guide <NUM> and the wound package Pw in the yarn running direction, and is configured to detect the tension applied to the yarn Y. The tension sensor <NUM> is electrically connected to the controller <NUM>.

The controller <NUM> includes members such as a CPU, a ROM, and a RAM. The controller <NUM> controls components by using the CPU and a program stored in the ROM, based on the parameters stored in the RAM etc..

In the re-winder <NUM> structured as described above, as the yarn supply package Ps is rotationally driven by the unwinding motor <NUM>, the yarn Y is unwound from the yarn supply package Ps. An unwinding speed (referred to as V1) at which the yarn Y is unwound is mainly determined in accordance with the rotation speed of the yarn supply package Ps and the diameter of the yarn supply package Ps. The yarn Y having been unwound from the yarn supply package Ps is guided upward from the direction changing guide <NUM> (toward one side in a guide direction of the present invention), i.e., toward the yarn guide <NUM> side via the direction changing guide <NUM>. In the present embodiment, a guide direction in which the yarn Y is guided by the direction changing guide <NUM> is parallel to the up-down direction (see <FIG>). Subsequently, the yarn Y runs toward the winding unit <NUM> via the yarn guides <NUM> and <NUM> and the tension sensor <NUM>. While being traversed by the traverse guide <NUM>, the yarn Y is wound onto the winding bobbin Bw rotationally driven by the winding motor <NUM>. A winding speed (referred to as V2) at which the yarn Y is wound is mainly determined in accordance with the rotation speed of the wound package Pw and the diameter of the wound package Pw. As described above, the wound package Pw is formed (winding operation).

The following will describe the details of the arrangement of the yarn supplying unit <NUM> with reference to <FIG> and <FIG>. <FIG> is a left side view of the yarn supplying unit <NUM>. <FIG> shows a state in which the direction changing guide <NUM> is passively moved. <FIG> is a plan view of the yarn supplying unit <NUM>. <FIG> shows a state in which the yarn Y is guided by bar guides <NUM>, and is a schematic diagram in which <FIG> is expanded along a circumferential direction of the yarn supply package Ps.

As shown in <FIG>, the yarn supplying unit <NUM> further includes a rail member <NUM>, bar guides <NUM> (separation units of the present invention), and a position sensor <NUM> (position detection unit of the present invention) in addition to the supporting table <NUM>, the unwinding motor <NUM>, the direction changing guide <NUM>, and the yarn guide <NUM> which are described above.

The rail member <NUM> is formed to allow the direction changing guide <NUM> to be freely movable. As shown in <FIG>, the rail member <NUM> is a member extending to be linear in the up-down direction. The rail member <NUM> is provided outside the yarn supply package Ps in the radial direction of the yarn supply package Ps, and the lower end of the rail member <NUM> is fixed to the supporting table <NUM>. For example, the rail member <NUM> extends between a position below a lower end face of the yarn supply package Ps and a position above an upper end face of the yarn supply package Ps. An extending direction of the rail member <NUM> is a moving direction in which the direction changing guide <NUM> moves.

The direction changing guide <NUM> will be further detailed. As shown in <FIG>, the direction changing guide <NUM> includes a main body portion <NUM> moving along the rail member <NUM> and a contact portion <NUM> making contact with the yarn Y and guides the yarn Y. In the main body portion <NUM>, a through hole <NUM> having a similar shape to a cross section orthogonal to the extending direction of the rail member <NUM> is formed. Into the through hole <NUM>, the rail member <NUM> is inserted. In other words, the main body portion <NUM> is loosely fitted to, e. , the rail member <NUM>, and is freely movable in the extending direction of the rail member <NUM>. Alternatively, for example, the main body portion <NUM> may be configured to be smoothly slid relative to the rail member <NUM> and an inner circumferential surface of the through hole <NUM> of the main body portion <NUM> may be in contact with an entire circumferential surface of the rail member <NUM>. For example, the contact portion <NUM> is integrally formed with the main body portion <NUM> or fixed to the main body portion <NUM>, and moves together with the main body portion <NUM>. Because of this, the direction changing guide <NUM> is movably guided (see <FIG>) along the rail member <NUM>. The details will be given later.

Each bar guide <NUM> is provided for ensuring a long yarn path between the yarn supply package Ps and the direction changing guide <NUM> in the yarn running direction. The bar guide <NUM> is a cylindrical rod-shaped member extending in, e.g., the up-down direction. In the present embodiment, two bar guides <NUM> (bar guide <NUM> and bar guide <NUM> in this order from the upstream side in the yarn running direction) are provided. However, the number of the bar guides <NUM> is not limited to this. Each bar guide <NUM> is provided outside the yarn supply package Ps in the radial direction of the yarn supply package Ps. The lower end of the bar guide <NUM> is fixed to the supporting table <NUM>. An extending direction of the bar guide <NUM> is parallel to the axial direction of the yarn supply package Ps. The contact part of the bar guide <NUM>, i.e., the part of the bar guide <NUM> which makes contact with the yarn Y extends (see <FIG> and <FIG>) in the axial direction of the yarn supply package Ps. The bar guide <NUM> extends between a position below the lower end face of the yarn supply package Ps and a position above the upper end face of the yarn supply package Ps. In other words, the bar guide <NUM> extends at least from a height of one end of the yarn supply package Ps to a height of the other end of the yarn supply package Ps in the axial direction of the yarn supply package Ps.

Because these bar guides <NUM> are provided, the yarn Y having been unwound from the yarn supply package Ps runs (see <FIG>) to draw a tangent connecting the surface of the yarn supply package Ps with one of the bar guides <NUM> (the upstream bar guide <NUM> in the yarn running direction). To be more specific, the yarn Y runs from a take-up point <NUM> toward the bar guide <NUM>. The yarn Y reaches the direction changing guide <NUM> via the bar guides <NUM> and <NUM>.

The yarn Y running between the yarn supply package Ps and the direction changing guide <NUM> in the yarn running direction is traversed (indicated by an arrow <NUM> in <FIG>) in the axial direction of the yarn supply package Ps about the direction changing guide <NUM> functioning as a fulcrum. An angle at which the yarn Y is traversed about the direction changing guide <NUM> functioning as a fulcrum is referred to as a traverse angle Θ1. If the bar guides <NUM> are not provided, the position of the take-up point <NUM> is close to the direction changing guide <NUM> and the traverse guide Θ1 is increased. As a result, the variation in the length of the yarn path from the yarn supply package Ps to the direction changing guide <NUM> is large. Because the bar guides <NUM> are provided in the present embodiment, the yarn path from the yarn supply package Ps to the direction changing guide <NUM> is long so that the traverse angle Θ1 is small. Therefore, the variation in the length of the yarn path described above is suppressed.

The position sensor <NUM> is configured to detect a position of the direction changing guide <NUM> in the moving direction. The position sensor <NUM> is, e.g., an optical sensor including an unillustrated light emitter and an unillustrated light receiver. The position sensor <NUM> is provided outside the traveling range of the direction changing guide <NUM>, and fixed to the supporting table <NUM>. The position sensor <NUM> emits light by using the light emitter and detects the light which is reflected by the direction changing guide <NUM> by using the light receiver, so as to detect a distance (referred to as D; see <FIG>) between the direction changing guide <NUM> and the position sensor <NUM>. The position sensor <NUM> is electrically connected to the controller <NUM>, and sends the information regarding the distance to the controller <NUM>.

The details of the direction changing guide <NUM> will be described. If the moving direction of the direction changing guide <NUM> is significantly tilted with respect to the above-described guide direction (direction in which the yarn Y is guided by the direction changing guide <NUM>), problems such as the following problem may occur. When the direction changing guide <NUM> significantly moves, the yarn Y provided downstream of the direction changing guide <NUM> in the yarn running direction is easily and significantly swung by the passive movement of the direction changing guide <NUM>. Because of this, when a member is provided in the vicinity of the yarn path, the member may interfere with the yarn Y. In the present embodiment, as shown in <FIG>, the moving direction of the direction changing guide <NUM> is parallel to the guide direction (up-down direction). In other words, the rail member <NUM> extends in the up-down direction, and the direction changing guide <NUM> is movable in the up-down direction along the rail member <NUM>. Because of this, as shown in <FIG>, the horizontal movement of the yarn Y running downstream of the direction changing guide <NUM> in the yarn running direction is suppressed even when the direction changing guide <NUM> moves. In other words, the horizontal swing of the yarn Y (i.e., variation of the yarn path) provided downstream of the direction changing guide <NUM> in the yarn running direction is suppressed.

The gravity (a predetermined power of the present invention; indicated by an arrow <NUM> in <FIG>) acts on the direction changing guide <NUM>. As described above, the direction changing guide <NUM> is movable in the up-down direction along the rail member <NUM>. In other words, the direction changing guide <NUM> hangs down from the intermediate part of the yarn Y in the yarn running direction. The yarn Y provided above the direction changing guide <NUM> (provided downstream of the direction changing guide <NUM> in the yarn running direction) is always pulled downward (toward the other side in the guide direction of the present invention). Because of this, tension is applied to the yarn Y. The strength in the tension of the yarn Y is substantially determined by the weight of the direction changing guide <NUM>. In other words, the strength in tension varies in accordance with the weight of the direction changing guide <NUM>. For example, by attaching a spindle (not illustrated) to the direction changing guide <NUM>, the magnitude of the gravity acting on the direction changing guide <NUM> is changed so as to change the magnitude of the tension applied to the yarn Y.

As described above, the direction changing guide <NUM> includes the main body portion <NUM> and the contact portion <NUM>, and is freely movable along the rail member <NUM>. In other words, the direction changing guide <NUM> has a simple structure as compared to, e.g., a typical dancer roller connected to a dancer arm. Therefore, the mass (inertial mass) of a member configured to be passively moved is small, and hence followability is good. The weight of the direction changing guide <NUM> is, e.g., <NUM> to <NUM>.

The moving direction of the direction changing guide <NUM> is parallel to the axial direction of the yarn supply package Ps. If the moving direction is tilted with respect to the axial direction of the yarn supply package Ps, the direction changing guide <NUM> moves so that a distance between the direction changing guide <NUM> and the surface of the yarn supply package Ps varies. As a result, the length of the yarn path varies. In this regard, because the moving direction is parallel to the axial direction of the yarn supply package Ps in the present embodiment, the variation in the length of the yarn path described above is suppressed.

In the structure described above, the yarn Y having been unwound from the yarn supply package Ps is guided upward by the direction changing guide <NUM>. The gravity acts on the direction changing guide <NUM>, and the yarn Y is always pulled downward by the direction changing guide <NUM> so that tension is applied to the yarn Y. If the position of the direction changing guide <NUM> is fixed, the tension varies in accordance with the difference between the winding speed and the unwinding speed. However, in the present embodiment, the tension is substantially determined by the magnitude of power in which the yarn Y is pulled downward by the direction changing guide <NUM>. Because the direction changing guide <NUM> is freely movable, the variation in the tension of the yarn Y is suppressed as follows. For example, because of traversing (traversing at the time of yarn unwinding or yarn winding) of the yarn Y, when the winding speed (V2) of the yarn Y is relatively fast as compared to the unwinding speed (V1) of the yarn Y, the direction changing guide <NUM> is pulled upward by the yarn Y and passively moved. The yarn path is therefore arranged to be short. As a result, the excessive tension of the yarn Y due to increase in tension is suppressed. Meanwhile, when the winding speed of the yarn Y is relatively slow, the yarn Y is about to slacken. However, because the gravity acts on the direction changing guide <NUM> as described above, the direction changing guide <NUM> pulls the yarn Y while passively moving downward. As a result, the slack of the yarn Y due to decrease in tension is suppressed.

The following will describe an example of the positional control of the direction changing guide <NUM> by the controller <NUM>, mainly with reference to <FIG> is a graph showing a relationship between a difference (V2-V1) between the winding speed (V2) of the yarn Y and the unwinding speed (V1) of the yarn Y and the moving speed of the direction changing guide <NUM>. <FIG> is a graph showing variations over time of the position (to be precise, distance between the direction changing guide <NUM> and the position sensor <NUM> in the moving direction) of the direction changing guide <NUM>.

For example, when the diameter of the yarn supply package Ps is gradually decreased as the unwinding of the yarn Y advances in a state in which the rotation speed (rotation number) of the yarn supply package Ps is constant, the winding speed of the yarn Y is relatively increased because the unwinding speed of the yarn Y is decreased. Therefore, the direction changing guide <NUM> is pulled upward by the yarn Y and passively moved. As shown in <FIG>, when a value calculated by subtracting V1 from V2 is large, the moving speed (ΔD/Δt) of the direction changing guide <NUM> is also large. In this regard, when the direction changing guide <NUM> moves outward (upward) of the upper end face of the yarn supply package Ps in the axial direction of the yarn supply package Ps, the yarn Y may drop off from the upper end face of the yarn supply package Ps and may not be able to properly run. In other words, when the distance (D) between the position sensor <NUM> and the direction changing guide <NUM> is longer than a distance (Da) between the position sensor <NUM> and the upper end face of the yarn supply package Ps in the axial direction of the yarn supply package Ps, the above-described problem occurs. In addition to that, when the distance between the position sensor <NUM> and the direction changing guide <NUM> is shorter than a distance (Db) between the position sensor <NUM> and the lower end face of the yarn supply package Ps, the same problem occurs. In order to solve this problem, the direction changing guide <NUM> is controlled to be always positioned inside the yarn supply package Ps in the axial direction of the yarn supply package Ps. To achieve this, the controller <NUM> (see <FIG>) controls, for example, the unwinding motor <NUM> as described below so as to control the position of the direction changing guide <NUM>. For example, a typical PID control may be used as a control method.

For example, the controller <NUM> stores the information regarding a target position (target distance) of the direction changing guide <NUM> in the up-down direction. The target distance is, e.g., a medium value (see <FIG>) between the distances Da and Db described above. An initial state is a state in which the unwinding speed of the yarn Y and the winding speed of the yarn Y are substantially identical with each other, the direction changing guide <NUM> is in substantially stationary at the target position, and the winding operation of the yarn Y is performed. After that, the unwinding speed of the yarn Y is decreased (a value calculated by subtracting V1 from V2 is larger than <NUM>) due to decrease in the diameter of the yarn supply package Ps. Because of this, when the position sensor <NUM> detects that the direction changing guide <NUM> moves above the target position, the controller <NUM> controls the unwinding motor <NUM> to increase the rotation speed of the yarn supply package Ps. Because of this, the unwinding speed of the yarn Y is relatively fast (a value calculated by subtracting V1 from V2 is smaller than <NUM>), and hence the direction changing guide <NUM> moves downward. Meanwhile, when the position sensor <NUM> detects that the direction changing guide <NUM> moves below the target position, the controller <NUM> decreases the rotation speed of the yarn supply package Ps to decrease the unwinding speed of the yarn Y. Because of this, the unwinding speed of the yarn Y is relatively slow, and hence the direction changing guide <NUM> moves upward. As such, the controller <NUM> controls the unwinding motor <NUM> based on the detection result of the position sensor <NUM>, and performs feedback control of the position of the direction changing guide <NUM>. Because of this, the position of the direction changing guide <NUM> is arranged to be close (see <FIG>) to the target position.

As described above, the angle formed between the moving direction of the direction changing guide <NUM> and the guide direction is small. Because of this, as compared to a structure in which the moving direction and the guide direction are orthogonal to or substantially orthogonal to each other, the swing (variation of the yarn path) of the yarn Y due to the passive movement of the direction changing guide <NUM> is suppressed. In this regard, the yarn Y runs downstream of the direction changing guide <NUM> in the yarn running direction. Therefore, the variation of the yarn path due to the passive movement of the direction changing guide <NUM> is suppressed.

The moving direction of the direction changing guide <NUM> is parallel to the up-down direction. Because of this, the direction changing guide <NUM> is moved by means of the gravity. It is therefore possible to simplify the structure and to reduce the cost as compared to a structure in which power is applied to the direction changing guide <NUM> by, e.g., a spring. Furthermore, because the stable power provided by the gravity is applied to the direction changing guide <NUM>, the running yarn Y is stably pulled. Because of this, tension is stably applied to the running yarn Y.

The direction changing guide <NUM> is movably guided by the rail member <NUM>. It is therefore possible to simplify the structure of the direction changing guide <NUM> and to decrease the inertial mass of the direction changing guide <NUM> as compared to cases where, e.g., a typical dancer roller connected to a dancer arm is used as the direction changing guide <NUM>. As a result, the followability of the direction changing guide <NUM> is improved.

In the structure in which the rail member <NUM> extends in the up-down direction and the direction changing guide <NUM> is configured to be passively movable in a direction parallel to the up-down direction, the yarn Y is pulled straight downward by the gravity acting on the direction changing guide <NUM>. It is therefore possible to substantially determine the tension applied to the yarn Y in accordance with the weight of the direction changing guide <NUM>, and hence a desired tension is easily applied to the yarn Y with a simple structure.

The moving direction of the direction changing guide <NUM> is parallel to the axial direction of the yarn supply package Ps. This suppresses the variation of the distance between the direction changing guide <NUM> and the surface of the yarn supply package Ps at the time of moving of the direction changing guide <NUM>. It is therefore possible to suppress the variation in the length of the yarn path.

The axial direction of the yarn supply package Ps is parallel to the up-down direction. It is therefore possible to prevent the warping of the rotational shaft of the yarn supply package Ps due to the gravity. It is therefore possible to suppress the rotation of the yarn supply package Ps from becoming unstable.

The bar guides <NUM> are provided between the yarn supply package Ps and the direction changing guide <NUM> in the yarn running direction. In other words, the yarn Y having been unwound from the yarn supply package Ps runs toward the direction changing guide <NUM> via the bar guides <NUM>. Because of this, even when the direction changing guide <NUM> is not set apart from the yarn supply package Ps, the yarn path from the surface of the yarn supply package Ps to the direction changing guide <NUM> is long. Because the contact part of each bar guide <NUM> making contact with the yarn Y extends in the axial direction of the yarn supply package Ps, the yarn Y is smoothly slid in the axial direction. Therefore, the traverse angle Θ1 of the unwound yarn Y is arranged to be small while increase in size of a device is suppressed.

The controller <NUM> controls the unwinding motor <NUM> based on the detection result of the position sensor <NUM>. It is therefore possible to actively move the direction changing guide <NUM> by actively changing the difference between the winding speed of the yarn Y and the unwinding speed of the yarn Y. Because of this, the position of the direction changing guide <NUM> is controlled. For example, the feedback control is performed to move the position of the direction changing guide <NUM> close to the target position. It is therefore possible to suppress the large movement of the direction changing guide <NUM>.

The position sensor <NUM> is an optical sensor, and configured to optically detect the position of the direction changing guide <NUM>. If a magnetic sensor is used to magnetically detect the position of the direction changing guide <NUM>, the direction changing guide <NUM> is required to be formed of a conductor made of metal, etc. or to have such a conductor thereon. Therefore, the mass of the direction changing unit <NUM> may be increased to obstruct the passive movement of direction changing guide <NUM>. For example, in a structure in which a contact type position sensor is used, the sensor is easily worn away because the direction changing guide <NUM> frequently moves. This may lead to an early deterioration of the sensor. In the present embodiment, increase in the mass of the direction changing guide <NUM> and the early deterioration of the sensor, etc., are suppressed.

Claim 1:
A yarn winder (<NUM>) configured to form a wound package (Pw) by unwinding a yarn (Y) from a yarn supply package (Ps) which is rotating and by winding the yarn onto a winding bobbin (Bw) which is provided at least on one side of the yarn supply package (Ps) in an axial direction of the yarn supply package (Ps), the yarn winder (<NUM>) comprising a direction changing unit (<NUM>) which is provided outside the yarn supply package (Ps) in a radial direction of the yarn supply package (Ps) and which is configured to guide the yarn to one side in a guide direction having a component in the axial direction,
the direction changing unit (<NUM>) being configured to be movable in a moving direction, the moving direction and the guide direction forming an angle (θ2) which is <NUM> degrees or less, and a predetermined power being applied to the direction changing unit (<NUM>) at least toward the other side in the guide direction,
characterized in that the direction changing unit (<NUM>) is configured to be freely movable in the moving direction and in that the yarn winder (<NUM>) further comprises:
an unwinding driving unit (<NUM>) configured to rotationally drive the yarn supply package (Ps);
a winding driving unit (<NUM>) configured to rotationally drive the wound package (Pw);
a position detection unit (<NUM>) configured to detect a position of the direction changing unit (<NUM>) in the moving direction; and
a controller (<NUM>) configured to control at least one of the unwinding driving unit (<NUM>) and the winding driving unit (<NUM>) based on a detection result provided by the position detection unit (<NUM>).