EP1081082A2

EP1081082A2 - Traverse device and method

Info

Publication number: EP1081082A2
Application number: EP00118313A
Authority: EP
Inventors: Koichiro Oshiumi; Yoshihiro Kino
Original assignee: Murata Machinery Ltd
Current assignee: Murata Machinery Ltd
Priority date: 1999-09-01
Filing date: 2000-08-23
Publication date: 2001-03-07
Anticipated expiration: 2020-08-23
Also published as: EP1081082A3; EP1081082B1; DE60029523D1; DE60029523T2; JP3292177B2; JP2001072334A

Abstract

The present invention provides a simply structured traverse device that can arbitrarily change a traverse range to obtain packages in an arbitrary form. A traverse device comprises an oscillating member 11 having a yarn guide, a voice coil motor 12 connected to the oscillating member 11 and driven normally and reversely within a predetermined range, and control means 13 for controlling oscillation of the voice coil motor 12, the control means determining a range within which the oscillating member 11 is oscillated .

Description

Field of the Invention

The present invention relates to a traverse device and method for traversing a yarn that is wound into a package.

Background of the Invention

A known traverse device and method of this kind traverses a yarn while transferring it between an upper and lower sets of wings that rotate in opposite directions.

This wing traverse device does not easily accommodate a mechanism for changing a position where traversing is turned, that is, a position where a yarn is transffered between the sets of wings, so that it is difficult to arbitrarily change a right and left traverse turn positions, that is, a traverse range in order to form packages in an arbitrary form.

It is contemplated that a yarn guide for threading a yarn may be connected to a linear motor so as to be reciprocated to arbitrarily change the right and left traverse turn positions. In this case, however, the linear motor requires a motor stroke corresponding to the traverse range, resulting in an increase in the size of the entire device including the linear motor.

The present invention is provided in view of these problems, and it is an object thereof to provide a simply structured traverse device that can arbitrarily change the traverse range to form packages in an arbitrary form.

Summary of the Invention

To attain the above object, the present invention is a traverse device comprising an oscillating member having a yarn guide, a voice coil motor connected to the oscillating member and driven normally and reversely within a predetermined range, and control means for controlling the normal and reverse driving of the voice coil motor, the control means determining a range within which the oscillating member is oscillated.

With this configuration, a yarn traverse range is determined by the oscillating range of the oscillating member, which is in turn determined by the control means for controlling the motor. Thus, by changing the oscillating range of the oscillating member, a traverse width can be gradually narrowed, that is, a position where traversing is turned can be gradually moved inward to easily wind a yarn into a tapered-end package or the traverse width can be periodically or non-periodically narrowed, that is, the traverse turn position can be periodically or non-periodically moved inward to carry out creeping to prevent saddle bag shapes.

Normal and reverse driving of the voice coil motor within a predetermined range is controlled by a command value such as a triangular wave in such a manner that the normal and reverse driving operations are switched at peaks or bottoms of the command value, thereby enabling high-speed braking and acceleration before and after the oscillating member is turned. In addition, high-speed turns are achieved by directly attaching an elongated light oscillating member to a shaft of the voice coil motor while attaching a small light yarn guide to a tip of the oscillating member.

Alternatively, the present invention is a traverse device comprising an oscillating member having a yarn guide, a motor connected to the oscillating member and driven normally and reversely within a predetermined range, and control means for controlling the normal and reverse driving of the motor, a plurality of the oscillating members being arranged in a traverse direction so as to transfer a yarn between the adjacent oscillating members.

With this configuration, the traverse range is divided into two or more so that oscillating ranges of the two or more short oscillating members can be combined together to obtain a wide traverse range. The short oscillating members serve to reduce inertia while increasing a turn speed.

Alternatively, the present invention is a traverse device that individually controls oscillation of the plurality of oscillating members.

With this configuration, by changing driving timings and/or driving ranges for the plurality of oscillating members, positions where the yarn is transferred between the oscillating members can be shifted to suppress straight winding at these transfer positions.

Alternatively, the present invention is a traverse device comprising detection means for detecting a normal and reverse driving range of the motor over the entire range.

With this configuration, the detection means can be used for feedback control to accurately control the traverse turn positions. Additionally, if the yarn is transferred between the plurality of oscillating members, yarn transfer positions can be accurately controlled by, for example, controlling oscillation of a receiving-side oscillating member depending on the position of a delivering-side oscillating position.

Brief Description of the Drawings

Figure 1 is a schematic structural drawing of a traverse device according to the present invention.

Figure 2 is a block diagram of a control section.

Figure 3 is graph showing how a command voltage is output from the control section.

Figure 4 is a schematic structural drawing of a traverse device showing another example of the present invention.

Figure 5 is a graph showing how a command voltage is output from a control section for each arm.

Figure 6 is a partial structural drawing of a traverse device showing yet another example of the present invention.

Detailed Description of the Preferred Embodiments

Embodiments of the present invention will be described with reference to the drawings.

In Figure 1, a traverse device 1 comprises an arm (an oscillating member) 11, a voice coil motor 12, a control section 13, and a detection section 14. The traverse device 1 has no mechanical part such as a damper which determines a position where oscillation of the arm 11 is inverted, and a traverse range L is determined by oscillation of the arm 11 connected to the voice coil motor 12. A yarn Y traversed by the traverse device 1 is wound into a package 3 that is in contact with a rotatively driven friction drum 2.

A yarn guide 21 for guiding the yarn Y is attached to a tip of the arm 11. The arm 11 has the other side or its intermediate portion connected to a shaft 22 so as to oscillate around the shaft 22. The arm 11 has the voice coil motor 12 connected to the other end thereof. The arm 11 constitutes an oscillating member having the yarn guide and connected to the voice coil motor 12 so as to be normally and reversely driven within a predetermined range.

The voice coil motor (oscillating motor) 12 provided at the other end of the arm 11 and driven normally and reversely within a predetermined range comprises a stator 23 comprising a permanent magnet shaped like a fan extended around the shaft 22 and a movable member 24 provided to surround the stator 23 and comprising a fan-shaped air-core coil. The relationship between the stator 23 and the movable member 24 is similar to that between a magnet and a coil, and the movable member 24 is oscillated around the shaft 22 by means of a driving force exerted based on interactions between a current flowing through the coil and magnetic fields crossing the current. In this voice coil motor 12, a permanent magnet surface of the stator 23 which is opposed to the movable member 24 has N or S poles contiguously disposed in a driving direction, compared to the other linear motors having N and S poles alternately disposed in the driving direction. Accordingly, when the movable member 24 is driven in one direction, the direction of a current flowing through a coil in the movable member 24 need not be switched. The movable member 24, which is driven normally and reversely within a range within which the stator 23 is present is supplied with power via flexible power-supplying line. The stator 23 may be a coil, while the movable member 24 may be a permanent magnet.

The normal and reverse driving range of the movable member 24 is determined by a voltage supplied to the coil. Consequently, to change turn positions at traverse ends, a peak height (amplitude) of a triangular wave voltage supplied to the coil can be changed. The power supplied to the coil is not limited to the triangular wave voltage.

When the movable member 24 is constructed using the air-core coil, its weight can be reduced to allow the arm 11 to be inverted at a high speed. In addition, since the stator 23 is shaped like a fan covering the normal and reverse driving range of the movable member 24 and the movable member 24 may be sized to move along the stator 23, the weight of the movable member 24 and this its inertia can be reduced, compared to motors that rotate through 360 degrees. As a result, the arm 11 can be inverted at a high speed when its direction is changed.

The control section 13 (control means) has a servo function and outputs a command signal to the voice coil motor 12 to control oscillations effected by the voice coil motor 12. The control section 13 is provided for each voice coil motor 12. Preferably, the detection section 14 (detection means) is, for example, a rotary encoder that can detect the oscillation of the shaft 22 over the entire range. The control section 13 uses feedback control based on an output from the detection section 14 to arbitrarily control a position where and a time when an oscillation is effected by the voice coil motor 12.

Figure 2 shows a specific example of the control section 13 including an analog servo function. In this example, the detection section 14 comprises a magneto-resistance element that varies a resistance value depending on the position of the movable member 24. In the feedback circuit shown in Figure 2, a voltage corresponding to a difference between an output voltage value from the magneto-resistance element (detection section 14) and a command voltage value is output to the voice coil motor 12 through a comparator 26 and supplied to the coil (movable member 24) of the voice coil motor 12, which effects predetermined normal and reverse driving in a manner following the command value. That is, a current corresponding to the difference between the output voltage value from the detection section 14 and the command voltage value flows through the coil of the voice coil motor 12. When the output voltage value from the detection section 14 equals the command voltage value, an output from the comparator 26 becomes zero to cause no current to flow through the voice coil motor 12. Another example of the control section 13 may include a digital servo function. In addition, the present invention is not limited to the feedback control, but open control can be employed where a spring is provided for the oscillating shaft so that its position is controlled while maintaining the balance with an urging force of the spring.

Figure 3 is a graph showing an example of a command value output from the control section 13 in Figure 2. The command value is output as a triangular wave voltage. The height of the triangular wave determines the normal and reverse driving range of the voice coil motor 12, and the period of the triangular wave determines a speed at which the voice coil motor 12 is driven normally and reversely. This enables controlling of oscillating motions of the arm 11 connected to the voice coil motor 12. A current value is particularly high near a peak of the command value (near a position where the arm 11 is turned). This large variation in current induces braking before a turn as well as acceleration after a turn to enable the arm 11 to be inverted at a high speed without using an energy accumulating device against which the arm 11 collides.

Next, the operation of the traverse device configured as described above will be explained with reference to Figure 1. In the illustrated example, a tapered-end package is formed.

The control section 13 outputs a triangular wave of a predetermined height and a predetermined period to normally and reversely drive the voice coil motor 12 to traverse the yarn Y within the predetermined traverse range L, the yarn Y being guided by the yarn guide 21 disposed at the tip of the arm 11. The control section 13 provides such control that the triangular wave in Figure 3 has its height gradually reduced depending on the elapsed time or a measured yarn length. Accordingly, the traverse range L narrows gradually to allow a tapered-end package as shown in Figure 1 to be formed easily. In addition, a creeping operation of periodically or non-periodically mixing a lower triangular wave as shown by the alternate long and two short dashes line in Figure 3 can be performed to prevent saddle bag shapes from being formed at turn sections corresponding to opposite ends of the traverse range, thereby obtaining a package having a yarn layer with a straight surface.

Since the voice coil motor 12 is structured to normally and reversely drive the arm 11 in a fashion tracing a fan around the shaft 22, the normal and reverse driving range is limited to enable the size and inertia of the motor to be reduced.

In addition, no mechanical part such as a damper is provided at the turn portions of the oscillating range, so that the oscillating range, that is, traverse range of the arm 11 can be arbitrarily set to easily form tapered-end packages while performing a creeping operation to prevent formation of saddle bag shapes.

In addition, the weights of the arm 11 and the yarn guide 21 disposed at the tip thereof are minimized to enable the arm 11 to be turned at a high speed.

Since, however, a longer arm 11 limits high-speed turns, the above described traverse device with the single arm 11 is preferably applicable to a double twister or the like. The single arm type is also applicable to a spun yarn winder with a narrow traverse range.

Figure 4 is a schematic structural drawing of another traverse device according to the present invention. For example, four arms are arranged in juxtaposition in a traverse direction (an axial direction of a winding package) to accommodate high-speed traversing. Description of that part of the configuration of this traverse device which is common to the traverse device (single arm type) is omitted as appropriate.

The traverse device 30 comprises

units

31 and 32 for turning the yarn rightward or leftward and

central units

33 and 34 for transferring the yarn. Each of the units 31 to 34 has an arm 35, a voice coil motor (an oscillating motor) 36, a control section 37, and a detection section 38. In addition, a main control section 39 controls the control sections 37, and each control section 37 controls a position where the arm 35 is oscillated, based on a command from the main control section 39. The control sections 37 and the main control section 39 constitute control means. The traverse device may comprise two or more units, for example, only the right and left units and one central unit.

Since there are four units in Figure 4, the yarn is transferred from the right to left units or from the left to right units at a point P1 between the

units

31 and 33, a point P2 between the

units

33 and 34, and a point P3 between the

units

34 and 32. The arm 35 transfers the yarn during oscillation at the yarn transfer points P1, P2, and P3. That is, the delivering-side arm 35 stops the oscillation after transferring the yarn, and the receiving-side arm receives the yarn after starting oscillation. As a result, the yarn is transferred from the oscillating arm 35 to the subsequent oscillating arm 35, thereby allowing the yarn to be transferred at the points P1, P2, and P3 at a high speed. Appropriate guide plates are provided at the yarn transfer points P1, P2, and P3 to transfer the yarn from one yarn guide to another, but illustration thereof is omitted. For example, the guide plates are each shaped to instantly receive the yarn from the delivering-side yarn guide and to transfer it to the receiving-side yarn guide.

The present invention is not limited to the arm 35 that transfers the yarn during oscillation, but the delivering-side arm may stop at the transfer position, while the receiving-side arm may start oscillation at this transfer position, so that the yarn is transported over the total oscillating range of the plurality of arms.

Figure 5 is a graph showing timings in a command voltage generated by each control section 37 due to a command from the main control section 39 in Figure 4.

In the illustrated example, at a reference voltage (zero voltage), each arm 35 lies leftward. In response to an increase in voltage, the arm 35 of the left unit 31 oscillates rightward from a turn position T1 and transfers, at the point P2, the yarn to the arm 35 of the central unit 34. The arm 35 of the central unit 34 oscillates rightward and transfers, at the point P3, the yarn to the arm 35 of the right unit 32. Likewise, in response to an increase in voltage, the arm 35 of the right unit 32 moves to a turn position T2. Subsequently, in response to a voltage drop in each unit, the yarn is transferred from the turn position T2 to the turn position T1. Repeating the above operation allows the yarn Y to be traversed within the traverse range.

Thus, since the traverse range L in Figure 1 is divided, for example, into four, the oscillation range of the arm 35 of each of the units 31 to 34 is narrowed to correspondingly enable the arm 35 to be shortened. When the arm 35 is shortened, inertia exerted during oscillation is diminished to enable the size of the entire traverse device to be reduced to accommodate high-speed turns. The length of the arm 35 of each of the right and left units 31 and 32 (this length equals the distance from the oscillating shaft to the yarn guide) can also be reduced below that of each of the

central units

33 and 34 to accommodate high-speed turns. This reliably prevents saddle bag shapes from being formed at the right and left ends. Further, a pattern of an increase or decrease in voltage at each of the units 31 to 34 can be individually varied to shift the yarn transfer points P1, P2, and P3 in the traverse direction (the axial direction of the package) to hinder straight winding at these points P1, P2, and P3.

Figure 6 is a partial structural drawing of yet another traverse device. Two

units

40 and 41 are stacked on each other (in the direction of the oscillating shaft) in a right and left portions where traversing is turned, so that the yarn is transferred between an upper arm 42 and a lower arm 43, which are overlapping each other. In this case, a guide plate (not shown in the drawing) can be provided as appropriate to reliably transfer the yarn from the upper arm 42 to the lower arm 43.

In Figure 6, the upper arm 42, which is moving leftward to traverse the yarn Y, and the lower arm 43, which is empty and is moving rightward to also traverse the yarn Y, transfer the yarn therebetween at the turn point T1 where they overlap each other. Since the lower arm 43 reaches the turn point T1 while being accelerated, high-speed turns are achieved to more reliably prevent saddle bag shapes from being formed at the right and left ends.

As described above, according to the present invention, the yarn traverse range is determined by the oscillating range of the oscillating member, which is in turn determined by the control means for controlling the voice coil motor. Thus, by changing the oscillating range of the oscillating member, the traverse range can be gradually narrowed to easily wind the yarn into a tapered-end package or the traverse range can be periodically or non-periodically varied to carry out creeping to prevent saddle bag shapes.

In addition, due to its simple mechanical configuration including the oscillating member and the voice coil motor that is driven normally and reversely, the present invention eliminates the needs for drive transmission means such as an endless belt to thereby improve durability while enabling the size of the entire traverse device to be reduced.

Further, the voice coil motor that is subjected to a small inertia and that can be switched between normal and reverse driving at a high speed serves to achieve high-speed turns to enable accurate formation of packages in a predetermined form such as a tapered end while preventing saddle bag shapes.

Alternatively, according to the present invention, the traverse range is divided into two or more so that the oscillating ranges of the two or more short oscillating members can be combined together to obtain a wide traverse range. The short oscillating members serve to reduce the inertia while increasing the turn speed, thereby enabling packages in an accurate form to be obtained while preventing saddle bag shapes. In addition, the number of oscillating members can be augmented to accommodate a wide traverse range.

Alternatively, according to the present invention, by changing driving timings and/or driving ranges for the plurality of oscillating members, positions where the yarn is transferred between the oscillating members can be shifted to suppress straight winding at these transfer positions. As a result, despite the plurality of oscillating members, packages obtained each have an appropriate winding form.

Alternatively, according to the present invention, the detection means can be used for feedback control to accurately control the traverse turn positions. Additionally, if the yarn is transferred between the plurality of oscillating members, the yarn transfer positions can be accurately controlled. As a result, packages obtained have an appropriate winding form, and the yarn can be reliably transferred to prevent winding errors.

Claims

A traverse device characterized by comprising an oscillating member having a yarn guide, a voice coil motor connected to the oscillating member and driven normally and reversely within a predetermined range, and control means for controlling the normal and reverse driving of the voice coil motor, the control means determining a range within which said oscillating member is oscillated.
A traverse device according to Claim 1, characterized in that said control means controls the normal and reverse driving range based on an amplitude of a command value to said voice coil motor and controls a normal and reverse driving speed based on a period thereof.
A traverse device according to Claim 1 or Claim 2, characterized in that said voice coil motor comprises a stator shaped like a fan extended around an oscillating shaft of said oscillating member so as to cover the normal and reverse driving range of a movable member.
A traverse device characterized by comprising an oscillating member having a yarn guide, a motor connected to the oscillating member and driven normally and reversely within a predetermined range, and control means for controlling the normal and reverse driving of said motor, a plurality of said oscillating members being arranged in a traverse direction so as to transfer a yarn between the adjacent oscillating members.
A traverse device according to Claim 4, characterized in that two oscillating members are stacked at each traverse end in a direction of an oscillating shaft.
A traverse device according to Claim 4 or Claim 5, characterized in that said motor is a voice coil motor.
A traverse device according to any one of Claims 4 to 6, characterized in that said control means individually controls oscillation of said plurality of oscillating members.
A traverse device according to Claim 7, characterized by comprising detection means for detecting positions at which said plurality of oscillating members are oscillated, said controlling means controlling oscillation of a receiving-side oscillating member depending on a detected oscillating position of a delivering-side oscillating member.
A traverse device according to any one of Claims 4 to 8, characterized in that the oscillating members arranged at the traverse ends are shorter than oscillating members arranged in a central portion of a traverse range.
A method for traversing a yarn while using a normal and reverse driving motor to oscillate an oscillating member having a yarn guide, the method being characterized in that a command value to said motor is changed to vary a position at which traversing is turned as winding progresses.
A traverse method according to Claim 10, characterized in that said normal and reverse driving motor is a voice coil motor, and an amplitude of the command value to the voice coil motor is periodically or non-periodically changed to vary the traverse turn position.
A traverse method characterized by being configured so that a plurality of oscillating members each having a yarn guide are arranged in a traverse direction so as to transfer a yarn between the adjacent oscillating members, the method traversing the yarn while changing driving timings and/or driving ranges for the plurality of oscillating members to vary positions where the yarn is transferred between the oscillating members.