CN117166126B

CN117166126B - Yarn tension control device, knotting device and flat knitting machine

Info

Publication number: CN117166126B
Application number: CN202310605540.1A
Authority: CN
Inventors: 山田裕也
Original assignee: Shima Seiki Mfg Ltd
Current assignee: Shima Seiki Mfg Ltd
Priority date: 2022-06-02
Filing date: 2023-05-26
Publication date: 2025-11-07
Anticipated expiration: 2043-05-26
Also published as: CN117166126A; JP2023177483A; EP4286578B1; JP7776385B2; EP4286578A1; KR20230167706A

Abstract

The invention provides a yarn tension control device, a knotting device and a flat knitting machine. The yarn tension control device is capable of controlling the tension applied to the yarn. The yarn feeding device comprises a motor for generating a driving force, a cam configured to be rotatable by the driving force of the motor, a pair of yarn guides for guiding a yarn to a predetermined position, a spring for generating a biasing force, and an arm having an insertion hole and a pin, wherein the insertion hole is supported so as to be swingable along an imaginary plane passing between the pair of yarn guides and through which the yarn guided by the pair of yarn guides is inserted, the cam is capable of acting on the pin, the arm is biased in a direction of applying tension to the yarn by the spring, and the arm swings in a direction away from the pair of yarn guides with a position where the biasing force of the spring and the tension of the yarn are balanced as a reference by the action of the cam on the pin, so that the tension applied to the yarn is increased.

Description

Yarn tension control device, knotting device and flat knitting machine

Technical Field

The present invention relates to a yarn tension control device, a knotting device provided with the yarn tension control device, and a technique of a flat knitting machine.

Background

Conventionally, a device for applying tension to a yarn supplied to a textile machine by a biasing force of a spring is known. For example, patent document 1 discloses a device provided in a knot tying device, in which a yarn is subjected to a constant tension by the urging force of a spring. In addition, a device for applying tension to a yarn by a biasing force of a spring is also known to be provided in a flat knitting machine.

However, the device disclosed in patent document 1 has a problem that a certain tension is applied to the yarn in a state other than the knotting operation, and thus a load more than necessary is applied to the yarn. Accordingly, a yarn tension applying device capable of controlling tension applied to a yarn is desired.

[ Prior Art literature ]

[ Patent literature ]

Japanese patent No. 2614775 (patent document 1)

Disclosure of Invention

[ Problem ] to be solved by the invention

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a yarn tension control device, a knotting device, and a flat knitting machine capable of controlling tension applied to a yarn.

[ Means for solving the problems ]

The problems to be solved by the present invention are as described above, and means for solving the problems will be described below.

Specifically, the yarn tension control device according to the present invention includes a motor that generates a driving force, a cam configured to be rotatable by the driving force of the motor, a pair of yarn guides that guide a yarn to a predetermined position, a spring that generates a biasing force, and an arm that has an insertion portion that is supported so as to be swingable along a virtual plane passing between the pair of yarn guides and through which the yarn guided by the pair of yarn guides is inserted, the cam being capable of acting on the biasing portion, the arm being biased in a direction in which the spring biases the yarn, and the arm being biased by the cam on the biasing portion, and being swingable in a direction away from the pair of yarn guides with a position in which the biasing force of the spring and the tension of the yarn are balanced as a reference, thereby increasing the tension applied to the yarn.

With this configuration, the tension applied to the yarn can be controlled.

Further, the arm swings in a direction approaching the pair of yarn guides based on the position where the balance is achieved by the action of the cam on the action portion, and thereby tension applied to the yarn is reduced.

With this configuration, the tension applied to the yarn can be controlled more precisely.

In addition, one end of the spring is fixed to the arm, and the other end of the spring is fixed to the cam.

With this configuration, the urging force of the spring can be controlled.

The cam includes a first cam configured to be able to act on the acting portion of the arm, and a second cam to which the other end of the spring is fixed, and the cam is configured to be able to switch which of the first cam and the second cam is rotated by a driving force of the motor.

With this configuration, the biasing force of the spring can be controlled, and the tension applied to the yarn can be easily increased.

The cam includes a first cam configured to act on the acting portion of the arm, the other end of the spring is fixed to the second cam, one of the first cam and the second cam is fixed to a motor shaft of the motor, and the other of the first cam and the second cam is coupled to one of the first cam and the second cam via a differential device and configured to rotate in a direction opposite to the one of the first cam and the second cam in response to rotation of the one of the first cam and the second cam.

The knotting apparatus according to any one of claims 1 to 5 is provided with a yarn tension control device.

With this configuration, the tension applied to the yarn can be changed before, during, and after the knot is made.

In addition, the weft knitting machine is provided with the yarn tension control device according to any one of claims 1 to 5.

With this configuration, the transition length of the yarn at the time of reverse weft rotation at the knitting end can be suppressed.

[ Effect of the invention ]

As an effect of the present invention, the tension applied to the yarn can be controlled.

Drawings

Fig. 1 is a schematic view showing an example of a yarn feeding mechanism to which a yarn tension control device according to a first embodiment of the present invention is applied.

Fig. 2 is a perspective view of the yarn tension control device according to the first embodiment.

Fig. 3 is a bottom view of the yarn tension control device according to the first embodiment, as well.

Fig. 4 is a bottom view of the yarn tension control device according to the first embodiment.

Fig. 5 is a bottom view of the yarn tension control device according to the first embodiment, as well, showing the yarn tension control device after the completion of knotting.

In fig. 6, (a) is a bottom view of the cam or the like of the first other example, and (b) is a bottom view of the cam or the like of the second other example.

Fig. 7 is a perspective view of a yarn tension control device according to the second embodiment.

Fig. 8 is a side sectional view showing a state in which the first cam is engaged with the motor shaft, and (b) is a side sectional view showing a state in which the second cam is engaged with the motor shaft.

Fig. 9 is a bottom view of the yarn tension control device according to the second embodiment, (a) is a bottom view of the yarn tension control device before knotting, (b) is a bottom view of the yarn tension control device during knotting, and (c) is a bottom view of the yarn tension control device after knotting is completed.

Fig. 10 is a front view of a yarn tension control device according to the third embodiment.

Fig. 11 is a bottom view of the yarn tension control device according to the third embodiment, (a) is a bottom view of the yarn tension control device during knotting, (b) is a bottom view of the yarn tension control device at the end of knotting, and (c) is a bottom view of the yarn tension control device before knotting.

Fig. 12 is a schematic view showing an example of a yarn feeding mechanism in the case where a yarn tension control device is applied to a flat knitting machine.

[ Reference numerals description ]

3. Knotting device

4. Flat knitting machine

30. 50, 60 Line tension control device

31. Motor with a motor housing

33. Cam

37. Yarn guide

38. Arm

39. Recoil spring

53. 63 First cam

56. 66 Second cam

69. Differential gear

Detailed Description

In the following, directions indicated by arrows U, D, F, B, L, and R in the drawings are defined as an upper direction, a lower direction, a front direction, a rear direction, a left direction, and a right direction, respectively. In the drawings, each constituent is appropriately omitted for simplicity.

As shown in fig. 1, the yarn feeding mechanism 1 is configured to feed yarn a used for knitting a knitted fabric from a yarn cone 2 to a flat knitting machine 4 via a knotting device 3. In the yarn feeding mechanism 1, a knotting device 3 is disposed downstream of the yarn cone 2 in the yarn feeding direction, and a flat knitting machine 4 is disposed downstream of the knotting device 3 in the yarn feeding direction.

In the weft knitting machine 4, the yarn feeder 5 moves along the needle bed 7 in conjunction with the carriage 6. A plurality of knitting needles 8 are arranged in parallel on the needle bed 7, and the knitting needles 8 advance and retract with respect to the needle bed gap 9, draw the yarn a from the yarn feeder 5, and knit the knitted fabric product C.

The knotting device 3 splices a yarn a in use in the weft knitting machine 4 and a new yarn a wound around the yarn cone 2. The knotting device 3 includes a yarn selecting section 10 and a yarn joining section 20.

The yarn selecting section 10 is configured to be able to guide a yarn a selected from the plurality of yarns a supplied from the yarn cone 2 to the yarn joining section 20. The yarn joining section 20 is configured to be able to join the yarn a selected by the yarn selecting section 10 and the yarn a in use in the flat knitting machine 4. The yarn joining section 20 is provided on the downstream side in the yarn feeding direction of the yarn selecting section 10. The yarn receiving portion 20 is provided with a yarn tension control device 30.

The structure of the yarn tension control device 30 will be described below with reference to fig. 2 and 4. The cam 33 and the arm 38 are rotatable or swingable members, and the positions shown in fig. 2 and 4 will be described below.

The yarn tension control device 30 controls the tension of the yarn a when knotting is performed. The yarn tension control device 30 includes a motor 31, a motor base 32, a cam 33, a yarn guide 37, an arm 38, and a recoil spring 39.

The motor 31 generates a driving force. As the motor 31, any motor can be used, but a stepping motor and a servo motor are suitable. The motor 31 includes a motor shaft 31a rotatable by the generated driving force. The motor 31 is disposed so that the axial direction of the motor shaft 31a is oriented in the up-down direction, and is provided so that the rotation amount and the rotation direction of the motor shaft 31a can be adjusted by a control unit, not shown.

The motor base 32 supports the motor 31. The motor base 32 is formed in an appropriate shape capable of supporting the motor 31, and is provided below the motor 31 so that the motor shaft 31a is inserted therethrough. The motor base 32 is provided with a pin 32a.

The pin 32a is provided in the vicinity of a portion through which the motor shaft 31a is inserted, and extends downward from the lower surface of the motor base 32. The pin 32a engages with an end of a recoil spring 39 described later.

The cam 33 is configured to be rotatable by the driving force of the motor 31. More specifically, the cam 33 is inserted and fixed below the motor base 32 by the lower end of the motor shaft 31a, and is provided to rotate around the axis of the motor shaft 31a as the motor shaft 31a rotates. The cam 33 is formed in a substantially L-shaped plate shape, and is disposed with the plate surface facing in the up-down direction. The cam 33 has a first protrusion 35 and a second protrusion 36.

The first protrusion 35 is one of two protrusions forming a substantially L-shape of the cam 33, and acts on a pin 38b of an arm 38 described later when the cam 33 rotates clockwise in a bottom view. The first protrusion 35 is formed to extend substantially rightward from a portion through which the motor shaft 31a is inserted to a position where it can act on the pin 38b. The first protrusion 35 has a first pressing surface 35a facing the pin 38b, and the pin 38b is pressed by the first pressing surface 35a when the cam 33 rotates clockwise in the bottom view.

The second protrusion 36 is the other of the two protrusions forming the substantially L-shape of the cam 33, and acts on a pin 38b of an arm 38 described later when the cam 33 rotates counterclockwise in the bottom view. The second protrusion 36 is formed to extend substantially rearward from a portion through which the motor shaft 31a is inserted to a position where it can act on the pin 38b. The second protruding portion 36 is formed to extend in a direction substantially perpendicular to the first protruding portion 35. The second protrusion 36 has a second pressing surface 36a facing the pin 38b, and the pin 38b is pressed by the second pressing surface 36a when the cam 33 rotates counterclockwise in the bottom view.

The yarn guide 37 guides the yarn a to a predetermined position. The yarn guide 37 extends from the motor base 32 to a side (rear in the present embodiment) of the motor base 32. The yarn guides 37 are provided in a pair up and down. Hereinafter, the upper yarn guide 37 may be referred to as a yarn guide 37A, and the lower yarn guide 37 may be referred to as a yarn guide 37B. As shown in fig. 4, an insertion hole 37a is formed at the tip of the yarn guide 37, and the yarn a fed from the yarn cone 2 is inserted into the insertion hole 37a. The insertion hole 37A of the yarn guide 37A and the insertion hole 37A of the yarn guide 37B are formed at positions overlapping in the bottom view.

The arm 38 is used to change the tension applied to the yarn a guided by the yarn guide 37. The arm 38 is a rigid body formed in a long rod shape and a plate shape, and is disposed so that the plate surface faces in the up-down direction. The arm 38 is inserted through and fixed to the motor shaft 31a, and is provided to swing around the axis of the motor shaft 31 a. The arm 38 is provided between the motor base 32 and the cam 33 in the vertical direction, and between the yarn guide 37A and the yarn guide 37B, and is supported so as to be swingable along an imaginary plane passing between the yarn guide 37A and the yarn guide 37B. The virtual plane is a plane intersecting a line segment connecting the insertion hole 37A of the yarn guide 37A and the insertion hole 37A of the yarn guide 37B, and is a horizontal plane in the present embodiment. The arm 38 includes an insertion hole 38a and a pin 38b.

The insertion hole 38a shown in fig. 4 is formed so as to penetrate the tip end of the arm 38 upward and downward, and allows the yarn a guided by the yarn guide 37 to be inserted therethrough. The insertion hole 38a is formed at the same position as the distance from the axis center of the motor shaft 31a to the center of the insertion hole 38a in the plan view from the axis center of the motor shaft 31a to the center of the insertion hole 37a of the yarn carrier 37. In this way, the insertion hole 38a is formed at a position where the center of the insertion hole 38a can coincide with the center of the insertion hole 37a of the yarn carrier 37 when the arm 38 swings.

The cam 33 can act on the pin 38b. The pin 38b is formed in a cylindrical shape, and is provided so as to extend from the lower surface of the arm 38 to a position at the same height as the lower surface of the cam 33 or below the lower surface of the cam 33. The pin 38b is provided near the cam 33 in the longitudinal direction of the arm 38, and is provided at a position not overlapping the cam 33 in the bottom view. More specifically, the pin 38b is provided between the first protrusion 35 and the second protrusion 36 in a circumferential direction centering on the axis of the motor shaft 31a in a bottom view. In this way, the pin 38b is provided at a position where the first pressing surface 35a of the first protrusion 35 and the second pressing surface 36a of the second protrusion 36 can abut when the cam 33 rotates.

The recoil spring 39 biases the arm 38. The recoil spring 39 is provided between the motor base 32 and the arm 38 so that the motor shaft 31a is inserted into a center portion of the recoil spring 39. One end of the recoil spring 39 is fixed to the arm 38, and the other end of the recoil spring 39 is fixed to the pin 32a of the motor base 32. The recoil spring 39 thus provided biases the arm 38 in a direction that biases the yarn a, more specifically, in a direction in which the arm 38 swings counterclockwise in a bottom view. Fig. 4 shows a state in which the force of the recoil spring 39 applied to the arm 38 and the tension of the yarn a are balanced.

The operation of each component of the yarn tension control device 30 when controlling the tension of the yarn a will be described below with reference to fig. 3 to 5. The yarn tension control device 30 controls the tension applied to the yarn a when the yarn a selected by the yarn selecting unit 10 and the yarn a in use in the weft knitting machine 4 are knotted in the yarn joining unit 20. Hereinafter, the time before the knot is made is referred to as "before the knot is made", the time in the middle of the knot is referred to as "during the knot making", and the time when the knot is finally tightened during the knot making is referred to as "end of the knot".

As shown in fig. 3, before knotting, the motor 31 is driven to rotate the cam 33 clockwise in the bottom view from the position shown in fig. 4, so that the first pressing surface 35a of the first protrusion 35 abuts against the pin 38b of the arm 38. Then, by rotating the cam 33 clockwise in the bottom view, the first protrusion 35 presses the pin 38B of the arm 38 against the biasing force of the recoil spring 39, and the arm 38 swings clockwise in the bottom view from the position shown in fig. 4 where the biasing force of the recoil spring 39 applied to the arm 38 and the tension of the yarn a are balanced, that is, in the direction in which the tip end portion of the arm 38 approaches the insertion hole 37A of the yarn guides 37A and 37B in the top view, to a position where the center of the insertion hole 38a of the arm 38 coincides with the center of the insertion hole 37A of the yarn guide 37.

This can guide the yarn a to a position where no tension is applied to the yarn a. Therefore, an excessive load can be not applied to the yarn a before knotting. Hereinafter, the position of the arm 38 shown in fig. 3 is referred to as "first position".

As shown in fig. 4, in the knotting, the motor 31 is driven to rotate the cam 33 counterclockwise in the bottom view from the position shown in fig. 3, and the cam 33 is moved to a position where neither the first protrusion 35 nor the second protrusion 36 is in contact with the pin 38b of the arm 38. Then, the arm 38 is in a state where the cam 33 is not operated but is only biased by the recoil spring 39. At this time, the arm 38 swings counterclockwise from the first position shown in fig. 3 to the bottom view by a predetermined angle by the urging force of the recoil spring 39. Thereby, the portion of the yarn a inserted into the insertion hole 38a of the arm 38 is pulled by the arm 38.

Accordingly, the tension of the recoil spring 39 applied to the yarn a during the knot tying can eliminate the slackening of the yarn a caused during the knot tying. Hereinafter, the position of the arm 38 shown in fig. 4 is referred to as "second position".

As shown in fig. 5, when the knotting is completed, the motor 31 is driven to rotate the cam 33 counterclockwise in the bottom view from the position shown in fig. 4, so that the second pressing surface 36a of the second protrusion 36 abuts against the pin 38b of the arm 38. By further rotating the cam 33 counterclockwise in the bottom view, the second protrusion 36 presses the pin 38B of the arm 38, and the arm 38 swings counterclockwise in the bottom view, that is, in a direction away from the insertion hole 37A of the yarn guides 37A and 37B in the top view from the second position shown in fig. 4. Thereby, the yarn a is forcibly pulled by the arm 38.

Thus, when the knot is closed, the knot of the yarn a can be tightened by forcibly pulling the yarn a. Hereinafter, the position of the arm 38 shown in fig. 5 is referred to as "third position".

As described above, the yarn tension control device 30 according to the present embodiment can change the tension applied to the yarn a according to each case of knotting. Therefore, the load applied to the yarn a when the knot is not made can be reduced, and the slackening of the yarn a or the knot of the yarn a can be eliminated or made firm when the knot is made. Further, since the arm 38 is constituted by a rigid body, control excellent in responsiveness can be performed.

The first embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and can be appropriately modified within the scope of the technical idea of the invention described in the claims.

For example, in the present embodiment, the cam 33 swings the arm 38 clockwise in the bottom view and counterclockwise in the bottom view by 2 protrusions of the first protrusion 35 and the second protrusion 36, but 1 protrusion may swing the arm 38 clockwise in the bottom view and counterclockwise in the bottom view. That is, the cam 33 may not necessarily have 2 protrusions, but may have 1 protrusion.

Fig. 6 (a) shows a cam 33A as a first other example of the cam 33, and shows a state in which the biasing force of the recoil spring 39 applied to the arm 38 is balanced with the tension of the wire a. The cam 33A shown in fig. 6 (a) is different from the cam 33 shown in fig. 2 to 5 in that the second protrusion 36 is not provided. In the cam 33A, when it is desired to not apply a load to the yarn a before knotting, the cam 33A is rotated clockwise in the bottom view and the pin 38b of the arm 38 is pressed by the first pressing surface 35a, as in fig. 3. Thereby, the arm 38 can be swung to the first position shown in fig. 3.

On the other hand, when the yarn a is to be forcibly pulled at the end of knotting, the cam 33A is rotated counterclockwise by approximately 360 ° from the position shown in fig. 6 (a), and the pin 38b of the arm 38 is pressed by the second pressing surface 35b which is the surface opposite to the first pressing surface 35a of the first protrusion 35. Thereby, the arm 38 can be swung up to the third position shown in fig. 5, and the knot of the yarn a can be tightened.

In the present embodiment, one end of the recoil spring 39 is fixed to the arm 38, and the other end of the recoil spring 39 is fixed to the motor base 32, but the other end of the recoil spring 39 may be fixed to the cam 33 instead of being fixed to the motor base 32. Thus, by rotating the cam 33, the other end of the recoil spring 39 moves, and thus the urging force of the recoil spring 39 to the arm 38 can be changed. Accordingly, the tension applied to the yarn a during the knotting can be controlled according to the ease of stretching and retracting the yarn a.

Specifically, when the tension of the yarn a is excessively large due to the relatively difficult elongation of the yarn a or the like, the cam 33 can be rotated so that the urging force of the recoil spring 39 is reduced. On the other hand, when the tension of the yarn a applied by the recoil spring 39 is too small due to relatively easy elongation of the yarn a, the cam 33 can be rotated so that the urging force of the recoil spring 39 increases.

However, when the other end of the recoil spring 39 is fixed to the cam 33, if the cam 33 is rotated to press the arm 38 to swing, the arm 38 is retracted by the force of the recoil spring 39 as the first protrusion 35 or the second protrusion 36 of the cam 33 approaches the pin 38b of the arm 38, and there is a problem that the arm 38 cannot be aligned to the first position with high accuracy. In order to solve this problem, the cam 33B shown in fig. 6 (B) may be configured.

Fig. 6 (B) shows a cam 33B as a second other example of the cam 33, in which the biasing force of the recoil spring 39 applied to the arm 38 and the tension of the wire a are balanced. The cam 33B shown in fig. 6 (B) is different from the cam 33 shown in fig. 2 to 5 in that a third protrusion 46 is provided. In the cam 33B, the other end of the recoil spring 39 is fixed to the first protrusion 35. The third protrusion 46 extends substantially rightward from a portion through which the motor shaft 31a is inserted between the first protrusion 35 and the pin 38b of the arm 38. A third pressing surface 46a facing the pin 38b is formed on the third protrusion 46. The third pressing surface 46a is formed at a position closer to the pin 38b than the first pressing surface 35a of the first protrusion 35.

In the cam 33B, since the distance from the pin 38B of the arm 38 to the third pressing surface 46a is shorter than the distance from the first pressing surface 35a, when the cam 33B is rotated clockwise in the bottom view, the third pressing surface 46a can be easily brought into contact with the pin 38B before the arm 38 is retracted. On the other hand, when the cam 33B is rotated counterclockwise in the bottom view, the first protrusion 35 is separated from the arm 38, so that the urging force of the recoil spring 39 increases, and the tension of the yarn a increases with the increase of the urging force. When the yarn a reaches a predetermined tension, the displacement of the angle of the arm 38 due to the urging force of the recoil spring 39 converges, but the arm 38 swings to the third position shown in fig. 5 by the second protrusion 36 pressing the pin 38b, so that the yarn a can be forcibly pulled.

Further, a sensor for measuring the tension applied to the yarn a may be provided, and the position of the arm 38 may be adjusted based on the measurement value of the sensor. This can control the tension applied to the yarn a to a desired value.

Further, a motor capable of acquiring the shaft torque may be used as the motor 31, and the position of the arm 38 may be adjusted based on the value of the shaft torque acquired by the motor 31. This can control the tension applied to the yarn a to a desired value. The shaft torque obtained by the motor 31 includes not only the tension applied to the yarn a but also the biasing force of the recoil spring 39. Therefore, a sensor for detecting the position of the arm 38 is preferably provided, and the position of the end point of the recoil spring 39 can be grasped by the sensor. Accordingly, since the change in the urging force of the recoil spring 39 can be grasped, the tension applied to the yarn a can be calculated by subtracting the urging force of the recoil spring 39 from the shaft torque obtained by the motor 31.

Next, a yarn tension control device 50 according to a second embodiment will be described with reference to fig. 7 to 9. The yarn tension control device 50 according to the second embodiment is different from the yarn tension control device 30 according to the first embodiment mainly in that the lifting member 41a is provided on the motor shaft 31a, and in that the first cam 53 and the second cam 56 are provided in place of the cam 33. In fig. 7 to 9, the motor base 32 and the yarn guide 37 are not shown. The first cam 53, the second cam 56, and the arm 38 are rotatable or swingable members, but will be described below with reference to the positions shown in fig. 7 and 9 (b).

The lifting member 41a is formed in a hollow shape having one end opened, and is provided so as to house the motor shaft 31 a. The cross-sectional shape of the opening portion of the elevating member 41a is not limited, and for example, similar to the cross-sectional shape of the motor shaft 31a, the elevating member 41a is provided so as to be rotatable together with the motor shaft 31a, and is movable up and down by a solenoid, not shown, provided below the elevating member 41 a. The lower end of the lifting member 41a is formed in a shape capable of engaging with the first cam 53 and the second cam 56. The lower end portion of the lifting member 41a is formed in a polygonal shape in a bottom view, for example, a decade shape to a pentadecade shape in a bottom view, which is formed by expanding the diameter of the lifting member 41a from the other portion.

The first cam 53 is for swinging the arm 38 and allowing the lower end of the lifting member 41a to be inserted therethrough. The first cam 53 is formed in a plate shape, and is disposed so that the plate surface faces in the up-down direction. The first cam 53 has a projection 55.

The protrusion 55 extends from a portion through which the lifting member 41a is inserted to the left and rear to a position where it can act on the pin 38b of the arm 38, and abuts against the pin 38b when the first cam 53 rotates. The protrusion 55 has a first pressing surface 55a and a second pressing surface 55b, and when the first cam 53 rotates clockwise in the bottom view, the first pressing surface 55a presses the pin 38b, and when the first cam 53 rotates counterclockwise in the bottom view, the second pressing surface 55b presses the pin 38 b.

The second cam 56 is for controlling the urging force of the recoil spring 39, and the lifting member 41a is inserted above the first cam 53. The second cam 56 is formed in a plate shape, and the plate surface is disposed in the up-down direction. The second cam 56 has a projection 58.

The protrusion 58 extends substantially rightward from a portion through which the lifting member 41a is inserted. The other end of the recoil spring 39 is fixed to the projection 58.

The lifting member 41a is provided so that the lower end portion can move up and down between a position shown in fig. 8 (a) where it engages with the first cam 53 and a position shown in fig. 8 (b) where it engages with the second cam 56. When the lifting member 41a is positioned at the position shown in fig. 8 (a), the first cam 53 can be rotated by driving the motor 31. On the other hand, when the lifting member 41a is positioned at the position shown in fig. 8 (b), the second cam 56 can be rotated by driving the motor 31. In this way, the first cam 53 and the second cam 56 are configured to be capable of switching which of the first cam 53 and the second cam 56 rotates by the driving force of the motor 31.

Next, the operation of each component of the yarn tension control device 50 when controlling the tension of the yarn a will be described with reference to fig. 9.

As shown in fig. 9 (a), before knotting, the motor 31 is driven in a state in which the lifting member 41a is moved to the position shown in fig. 8 (a), and thereby the first cam 53 is rotated clockwise in the bottom view to press the pin 38b of the arm 38 with the first pressing surface 55 a. Thereby, the arm 38 can be swung to the first position shown in fig. 3.

As shown in fig. 9 (b), in knotting, the first cam 53 is rotated counterclockwise in the bottom view to a position where the protrusion 55 does not abut against the pin 38b of the arm 38. Then, the arm 38 swings counterclockwise in the bottom view to the second position shown in fig. 4 by the urging force of the recoil spring 39, and the portion of the yarn a inserted into the insertion hole 38a of the arm 38 is pulled by the arm 38. This eliminates the slackening of the yarn a caused by the knotting.

At this time, the second cam 56 can be rotated by driving the motor 31 in a state where the lifting member 41a is moved to the position shown in fig. 8 (b). This allows the biasing force of the recoil spring 39 applied to the arm 38 to be varied, and further allows the tension applied to the yarn a when the slackening of the yarn a is eliminated to be controlled.

By providing the cam for pressing the arm 38 and the cam for fixing the other end of the recoil spring 39 as separate members in this way, the operation for changing the biasing force of the recoil spring 39 and the forced tension applied to the yarn a by pulling the arm 38 can be performed independently, and both can be achieved.

As shown in fig. 9 (c), when the knotting is completed, the motor 31 is driven to rotate the first cam 53 counterclockwise in the bottom view in a state in which the lifting member 41a is moved to the position shown in fig. 8 (a), whereby the protrusion 55 presses the pin 38b of the arm 38. This allows the arm 38 to swing to the third position shown in fig. 5, and the knot of the yarn a can be tightened.

The second embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and can be appropriately modified within the scope of the technical idea of the invention described in the claims.

For example, in the present embodiment, the lifting member 41a is moved up and down by a solenoid or the like in order to switch which of the first cam 53 and the second cam 56 is rotated by the driving force of the motor 31, but the first cam 53 and the second cam 56 may be moved up and down, respectively.

Next, a yarn tension control device 60 according to a third embodiment will be described with reference to fig. 10 and 11. The yarn tension control device 60 according to the third embodiment is different from the yarn tension control device 30 according to the first embodiment mainly in that the first cam 63 and the second cam 66 are provided in place of the cam 33, and in that the differential gear 69 is provided. In fig. 10 and 11, the motor base 32 and the yarn guide 37 are not shown.

The first cam 63 is for swinging the arm 38, and is formed in the same shape as the first cam 53 of the second embodiment. The protrusion 65 of the first cam 63 has a pressing surface 65a, and when the first cam 63 rotates counterclockwise in a bottom view, the pin 38b is pressed by the pressing surface 65 a.

The second cam 66 is for controlling the urging force of the recoil spring 39 and is formed in the same shape as the second cam 56 of the second embodiment. The second cam 66 is fixed to the motor shaft 31a, and is provided to rotate around the axis of the motor shaft 31a as the motor shaft 31a rotates. The other end of the recoil spring 39 is fixed to the projection 68 of the second cam 66.

The first cam 63 is coupled to the second cam 66 via a differential gear 69 provided between the first cam 63 and the second cam 66. Thus, the first cam 63 is configured to rotate in a direction opposite to the direction in which the second cam 66 rotates, along with the rotation of the second cam 66 caused by the driving force of the motor 31.

Next, the operation of each component of the yarn tension control device 60 when controlling the tension of the yarn a will be described with reference to fig. 11.

In the case where the biasing force of the recoil spring 39 is to be changed during knotting, as shown in fig. 11 (a), the second cam 66 is rotated by the driving force of the motor 31, and the position of the other end of the recoil spring 39 is moved, whereby the biasing force of the recoil spring 39 can be changed. Specifically, by rotating the second cam 66 counterclockwise in the bottom view, the second cam 66 is separated from the arm 38, and thus the urging force of the recoil spring 39 increases. On the other hand, by rotating the second cam 66 clockwise in the bottom view, the second cam 66 approaches the arm 38, and thus the urging force of the recoil spring 39 decreases.

When the tension is to be forcibly applied to the yarn a at the end of the knot tying, as shown in fig. 11 (b), the second cam 66 is rotated clockwise in the bottom view by the driving force of the motor 31, whereby the first cam 63 is rotated counterclockwise in the bottom view, and the pressing surface 65a of the protrusion 65 is brought into contact with the pin 38b of the arm 38. Further, by rotating the first cam 63 counterclockwise in the bottom view, the protrusion 65 presses the pin 38b of the arm 38, and the arm 38 swings counterclockwise in the bottom view. This allows the arm 38 to swing to the third position shown in fig. 5, and the knot of the yarn a can be tightened.

When tension is not applied to the yarn a before knotting, the first cam 63 is rotated clockwise in the bottom view from the position shown in fig. 11 (b) by the driving force of the motor 31 as shown in fig. 11 (c). When the first cam 63 rotates clockwise in the bottom view, the arm 38 swings clockwise in the bottom view together with the first cam 63 in a state of being in contact with the first cam 63 by the urging force of the recoil spring 39. Thereby, the arm 38 can be swung to the first position shown in fig. 3.

As described above, the yarn tension control devices 30, 50, 60 according to the first to third embodiments of the present invention are provided in the knotting device 3, but may be provided in the flat knitting machine 4 as shown in fig. 12. An example in which the yarn tension control devices 30, 50, 60 are provided in the flat knitting machine 4 will be described below.

In a conventional flat knitting machine, when knitting yarn is fed from one of the left and right sides in the flat knitting machine, tension becomes small at the end of the knitting object on the side far from a yarn tension control device provided near the side surface of the flat knitting machine when the yarn feeder is reversed. Particularly, when a high-rigidity fiber is used as the yarn to be padded, there is a problem that the tension applied by the spring cannot follow the tension change of the yarn, and the transition of the yarn to be padded becomes long at the far side end of the knitted fabric during inversion.

In the present invention, the yarn tension control devices 30, 50, 60 are provided in the weft knitting machine 4, and thus when the yarn feeder at the side of the knitting end far from the yarn tension control devices 30, 50, 60 is reversed during yarn feeding with the high-stiffness fiber as the weft yarn, the arm 38 is swung to the third position shown in fig. 5 to enhance the tension applied to the yarn a, whereby the tension variation during the reversal can be absorbed, and the transition length of the yarn during the weft yarn reversal at the knitting end can be suppressed.

Claims

1. A yarn tension control device, wherein,

The device is provided with:

a motor (31) that generates a driving force;

a cam configured to be rotatable by a driving force of the motor (31);

a pair of yarn guides (37A, 37B) for guiding the yarn (A) to a predetermined position;

a spring (39) for generating a force, and

An arm (38) having an insertion portion (38 a) and an action portion (38B), wherein the insertion portion (38 a) is supported so as to be swingable along an imaginary plane passing between the pair of yarn guides (37A, 37B) and is configured to allow the yarn (A) guided by the pair of yarn guides (37A, 37B) to be inserted therethrough, wherein the cam is configured to be able to act on the action portion (38B), wherein the arm (38) is configured to be biased in a direction in which a tension is applied to the yarn (A) by the spring (39), and wherein the action portion (38B) is configured to act by the cam so as to swing in a direction away from the pair of yarn guides (37A, 37B) based on a position at which the biasing force of the spring (39) and the tension of the yarn (A) are balanced, thereby increasing the tension applied to the yarn (A).

2. Yarn tension control device according to claim 1, wherein,

The arm (38) swings in a direction approaching the pair of yarn guides (37A, 37B) based on the position where the balance is achieved by the action of the cam on the action portion (38B), thereby reducing the tension applied to the yarn (A).

3. Yarn tension control device according to claim 1 or 2, wherein,

One end of the spring (39) is fixed to the arm (38), and the other end of the spring (39) is fixed to the cam.

4. The yarn tension control device according to claim 3, wherein,

The cam includes a first cam (53) and a second cam (56), the first cam (53) is configured to be capable of acting on the acting portion (38 b) of the arm (38), the other end of the spring (39) is fixed to the second cam (56),

The cam is configured to be capable of switching rotation of either one of the first cam (53) and the second cam (56) by a driving force of the motor (31).

5. The yarn tension control device according to claim 3, wherein,

The cam includes a first cam (63) and a second cam (66), the first cam (63) is configured to act on the acting portion (38 b) of the arm (38), the other end of the spring (39) is fixed to the second cam (66),

Either one of the first cam (63) and the second cam (66) is fixed to a motor shaft (31 a) of the motor (31),

The other of the first cam (63) and the second cam (66) is coupled to either of the first cam (63) and the second cam (66) via a differential device (69), and is configured to rotate in a direction opposite to either of the first cam (63) and the second cam (66) in response to rotation of either of the first cam (63) and the second cam (66).

6. A knotting device, wherein,

A yarn tension control device (30, 50, 60) according to any one of claims 1 to 5.

7. A flat knitting machine, wherein,