JP7776385B2 - Yarn tension control device, knotter device and flat knitting machine - Google Patents

Description

The present invention relates to a yarn tension control device, as well as a knotter device and a flat knitting machine equipped with the yarn tension control device.

Conventionally, devices that apply tension to yarn supplied to a textile machine using the biasing force of a spring are known. For example, Patent Document 1 discloses a device that is provided in a knotter device and applies a constant tension to the yarn using the biasing force of a spring. It is also known that flatbed knitting machines are also provided with devices that apply tension to yarn using the biasing force of a spring.

However, the device disclosed in Patent Document 1 applies a constant tension to the thread even when not tying, which poses problems such as placing more strain than necessary on the thread. For this reason, there is a demand for a thread tensioning device that can control the tension applied to the thread.

Patent No. 2614775

The present invention was made in light of the above circumstances, and the problem it aims to solve is to provide a yarn tension control device, knotter device, and flat knitting machine that can control the tension applied to the yarn.

The above is the problem that this invention aims to solve, and next we will explain the means for solving this problem.

That is, the yarn tension control device according to the present invention comprises: a motor that generates a driving force; a cam that is rotatable by the driving force of the motor; a pair of yarn guides that guide the yarn to a predetermined position; a spring that generates a biasing force; an insertion portion that is supported so as to be swingable along an imaginary plane that passes between the pair of yarn guides and through which the yarn guided by the pair of yarn guides is inserted; and an action portion on which the cam can act, the arm being biased by the spring in a direction that applies tension to the yarn, and which increases the tension applied to the yarn by swinging in a direction away from the pair of yarn guides based on a position where the biasing force of the spring and the tension of the yarn are balanced due to the action of the cam on the action portion.
By configuring in this way, it is possible to control the tension applied to the thread.

In addition, the arm swings in a direction approaching the pair of thread guides based on the balanced position due to the action of the cam on the acting portion, thereby reducing the tension applied to the thread.
By configuring in this way, the tension applied to the thread can be controlled more precisely.

One end of the spring is fixed to the arm, and the other end of the spring is fixed to the cam.
By configuring in this way, the biasing force of the spring can be controlled.

The cam also 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 is configured to be able to switch between rotating the first cam and the second cam by the driving force of the motor.
By configuring in this way, it is possible to control the biasing force of the spring and to easily increase the tension applied to the thread.

The cam also includes a first cam configured to act on the acting portion of the arm and a second cam to which the other end of the spring is fixed, and either the first cam or the second cam is fixed to the motor shaft of the motor, and the other of the first cam or the second cam is connected to either the first cam or the second cam via a differential device and is configured to rotate in the opposite direction to either the first cam or the second cam as either the first cam or the second cam rotates.
By configuring in this way, it is possible to control the biasing force of the spring and to easily increase the tension applied to the thread.

The knotter device is provided with the yarn tension control device according to any one of claims 1 to 5.
By configuring in this way, it is possible to change the tension applied to the line before, during, and after tying.

A flat knitting machine is provided with a yarn tension control device according to any one of claims 1 to 5.
By configuring in this way, it is possible to prevent the weft yarn from being long when it is inverted at the end of the knitted fabric.

One of the advantages of this invention is that it is possible to control the tension applied to the thread.

1 is a schematic diagram 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. FIG. 10 is a bottom view of the yarn tension control device before tying the yarn. FIG. 10 is a bottom view of the yarn tension control device during tying. FIG. 10 is a bottom view of the yarn tension control device at the end of tying the yarn. 10A is a bottom view of a first modified example of a cam, etc. FIG. 10B is a bottom view of a second modified example of a cam, etc. FIG. 10 is a perspective view of a yarn tension control device according to a second embodiment. 10A is a side cross-sectional view showing a state in which a first cam and a motor shaft are engaged with each other, and FIG. 10B is a side cross-sectional view showing a state in which a second cam and a motor shaft are engaged with each other. 10A is a bottom view of the yarn tension control device before tying, FIG. 10B is a bottom view of the yarn tension control device during tying, and FIG. 10C is a bottom view of the yarn tension control device at the end of tying. FIG. 10 is a front view of a yarn tension control device according to a third embodiment. 10A is a bottom view of the yarn tension control device during tying, FIG. 10B is a bottom view of the yarn tension control device at the end of tying, and FIG. 10C is a bottom view of the yarn tension control device before tying. FIG. 2 is a schematic diagram showing an example of a yarn feeding mechanism when a yarn tension control device is applied to a flat knitting machine.

In the following explanation, the directions indicated by arrows U, D, F, B, L, and R in the figures will be defined as upward, downward, forward, backward, leftward, and rightward, respectively. Furthermore, in the figures, illustration of individual components has been omitted as appropriate to simplify the illustration.

As shown in Figure 1, the yarn feeding mechanism 1 is configured to supply yarn A used to knit a fabric from a yarn cone 2 to a flat knitting machine 4 via a knotter device 3. In the yarn feeding mechanism 1, the knotter device 3 is located downstream of the yarn cone 2 in the yarn feeding direction, and the flat knitting machine 4 is located downstream of the knotter device 3 in the yarn feeding direction.

In the flat knitting machine 4, the yarn feeder 5 moves along the needle bed 7 in conjunction with the carriage 6. A large number of knitting needles 8 are arranged side by side on the needle bed 7, and the knitting needles 8 move forward and backward into the needle gap 9, drawing in yarn A from the yarn feeder 5 and knitting the knitted fabric product C.

The knotter device 3 splices the yarn A currently in use in the flat knitting machine 4 with new yarn A wound around the yarn cone 2. The knotter device 3 includes a yarn selection unit 10 and a yarn splicing unit 20.

The yarn selection unit 10 is configured to guide a yarn A selected from multiple yarns A supplied from the yarn cone 2 to the yarn splicing unit 20. The yarn splicing unit 20 is configured to splice the yarn A selected by the yarn selection unit 10 with the yarn A currently being used in the flat knitting machine 4. The yarn splicing unit 20 is located downstream of the yarn selection unit 10 in the yarn feeding direction. The yarn splicing unit 20 is provided with a yarn tension control device 30.

The configuration of the thread tension control device 30 will be explained below using Figures 2 and 4. Note that the cam 33 and arm 38 are rotatable or swingable members, but the following explanation will be based on the positions shown in Figures 2 and 4.

The thread tension control device 30 controls the tension of thread A when tying a knot. The thread tension control device 30 includes a motor 31, a motor base 32, a cam 33, a thread guide 37, an arm 38, and a kick spring 39.

The motor 31 generates a driving force. Any motor can be used as the motor 31, but a stepping motor or servo motor is suitable. The motor 31 has a motor shaft 31a that can be rotated by the generated driving force. The motor 31 is arranged with the axis of the motor shaft 31a facing vertically, and the amount and direction of rotation 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 that can support the motor 31, and is installed below the motor 31 so that the motor shaft 31a passes through it. A pin 32a is provided on the motor base 32.

The pin 32a extends downward from the underside of the motor base 32 near the portion where the motor shaft 31a passes through. The end of the kick spring 39, described below, engages with the pin 32a.

The cam 33 is configured to be rotatable by the driving force of the motor 31. More specifically, the cam 33 is inserted into and fixed to the lower end of the motor shaft 31a below the motor base 32, and is configured to rotate about the axis of the motor shaft 31a as the motor shaft 31a rotates. The cam 33 is formed in a generally L-shaped plate shape, and is positioned with the plate surface facing up and down. A first protrusion 35 and a second protrusion 36 are formed on the cam 33.

The first protrusion 35 is one of two protrusions that make up the generally L-shaped shape of the cam 33, and acts on a pin 38b of the arm 38 (described below) when the cam 33 rotates clockwise when viewed from the bottom. The first protrusion 35 is formed to extend generally to the right from the portion through which the motor shaft 31a is inserted to a position where it can act on the pin 38b. The first protrusion 35 is formed with a first pressing surface 35a that faces the pin 38b, and the first pressing surface 35a presses against the pin 38b when the cam 33 rotates clockwise when viewed from the bottom.

The second protrusion 36 is the other of the two protrusions that make up the generally L-shaped shape of the cam 33, and acts on a pin 38b of the arm 38 (described below) when the cam 33 rotates counterclockwise in a bottom view. The second protrusion 36 is formed to extend generally rearward from the portion through which the motor shaft 31a is inserted to a position where it can act on the pin 38b. The second protrusion 36 is formed to extend generally perpendicular to the first protrusion 35. The second protrusion 36 is formed with a second pressing surface 36a that faces the pin 38b, and the second pressing surface 36a presses against the pin 38b when the cam 33 rotates counterclockwise in a bottom view.

The thread guide 37 guides thread A to a predetermined position. The thread guide 37 extends from the motor base 32 to the side of the motor base 32 (to the right in this embodiment). A pair of thread guides 37 are provided, one above the other. Hereinafter, the upper thread guide 37 may be referred to as thread guide 37A, and the lower thread guide 37 as thread guide 37B. As shown in Figure 4, an insertion hole 37a is formed at the tip of each thread guide 37, and thread A supplied from the thread cone 2 is inserted through the insertion hole 37a. The insertion holes 37a of thread guide 37A and 37a of thread guide 37B are formed in overlapping positions when viewed from the bottom.

The arm 38 is used to change the tension applied to the thread A guided by the thread guide 37. The arm 38 is a rigid body formed in the shape of a long rod and a plate, and is arranged with its plate surface facing up and down. The arm 38 is inserted into and fixed to the motor shaft 31a, and is arranged to swing around the axis of the motor shaft 31a. The arm 38 is arranged between the motor base 32 and the cam 33 in the up and down direction, and between the thread guide 37A and the thread guide 37B, and is supported so that it can swing freely along an imaginary plane that passes between the thread guide 37A and the thread guide 37B. The imaginary plane is a plane that intersects with a line segment connecting the insertion hole 37a of the thread guide 37A and the insertion hole 37a of the thread guide 37B, and is a horizontal plane in this embodiment. The arm 38 is equipped with an insertion hole 38a and a pin 38b.

The insertion hole 38a shown in Figure 4 is formed to pass vertically through the tip of the arm 38, and thread A guided by the thread guide 37 is inserted through it. The insertion hole 38a is formed at a position where the distance from the axial center of the motor shaft 31a to the center of the insertion hole 38a in a plan view is the same as the distance from the axial center of the motor shaft 31a to the center of the insertion hole 37a of the thread guide 37 in a plan view. 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 thread guide 37 when the arm 38 swings.

The pin 38b is actable by the cam 33. The pin 38b has a cylindrical outer shape and extends from the underside of the arm 38 to the same height as the underside of the cam 33 or below the underside of the cam 33. The pin 38b is located near the cam 33 in the longitudinal direction of the arm 38 and at a position that does not overlap with the cam 33 in a bottom view. More specifically, the pin 38b is located between the first protrusion 35 and the second protrusion 36 in the circumferential direction centered on the axis of the motor shaft 31a in a bottom view. In this way, the pin 38b is located 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 come into contact when the cam 33 rotates.

The kick spring 39 biases the arm 38. The kick spring 39 is provided between the motor base 32 and the arm 38, with the motor shaft 31a inserted through the center of the kick spring 39. One end of the kick spring 39 is fixed to the arm 38, and the other end of the kick spring 39 is fixed to the pin 32a of the motor base 32. The kick spring 39 thus provided biases the arm 38 in a direction that applies tension to the thread A, more specifically, in a direction that causes the arm 38 to swing counterclockwise when viewed from the bottom. Figure 4 shows a state in which the biasing force of the kick spring 39 applied to the arm 38 and the tension in the thread A are balanced.

The operation of each component of the yarn tension control device 30 when controlling the tension of yarn A will be described below using Figures 3 to 5. The yarn tension control device 30 controls the tension applied to yarn A when tying together yarn A selected by the yarn selection unit 10 in the yarn splicing unit 20 and yarn A being used in the flat knitting machine 4. Hereinafter, the period before tying will be referred to as "before tying," the period during tying will be referred to as "during tying," and the period when the knot is finally tightened in tying will be referred to as "end of tying."

As shown in Figure 3, before tying, the motor 31 is driven to rotate the cam 33 clockwise as viewed from the bottom from the position shown in Figure 4, thereby bringing the first pressing surface 35a of the first protrusion 35 into contact with the pin 38b of the arm 38. Further rotating the cam 33 clockwise as viewed from the bottom causes the first protrusion 35 to press the pin 38b of the arm 38 against the biasing force of the kick spring 39, and swings the arm 38 clockwise as viewed from the bottom from the position shown in Figure 4 where the biasing force of the kick spring 39 applied to the arm 38 and the tension of the thread A are balanced until the center of the insertion hole 38a of the arm 38 coincides with the center of the insertion hole 37a of the thread guide 37. In other words, the arm 38 is swung clockwise as viewed from the bottom from the position shown in Figure 4 where the biasing force of the kick spring 39 applied to the arm 38 is balanced with the tension of the thread A, in a direction in which the tip of the arm 38 approaches the insertion hole 37a of the thread guides 37A and 37B in a plan view.

This allows thread A to be guided to a position where no tension is applied to the thread A. Therefore, unnecessary stress is not placed on thread A before tying. Hereinafter, the position of arm 38 shown in Figure 3 will be referred to as the "first position."

As shown in Figure 4, during knotting, the motor 31 is driven to rotate the cam 33 counterclockwise as viewed from the bottom from the position shown in Figure 3, moving the cam 33 to a position where neither the first protrusion 35 nor the second protrusion 36 abuts the pin 38b of the arm 38. The arm 38 is then in a state where the cam 33 is not acting on it and only the biasing force of the kick spring 39 is applied. At this time, the biasing force of the kick spring 39 causes the arm 38 to swing a predetermined angle counterclockwise as viewed from the bottom from the first position shown in Figure 3. As a result, the portion of the thread A inserted through the insertion hole 38a of the arm 38 is pulled by the arm 38.

As a result, the tension of the kick spring 39 applied to the thread A during tying can remove any slack that occurs in the thread A during tying. Hereinafter, the position of the arm 38 shown in Figure 4 will be referred to as the "second position."

As shown in Figure 5, when tying ends, the motor 31 is driven to rotate the cam 33 counterclockwise from the position shown in Figure 4, causing the second pressing surface 36a of the second protrusion 36 to abut against the pin 38b of the arm 38. By further rotating the cam 33 counterclockwise from the bottom, the second protrusion 36 presses against the pin 38b of the arm 38, causing the arm 38 to swing further counterclockwise from the second position shown in Figure 4, i.e., in a direction away from the insertion holes 37a of the thread guides 37A and 37B in a plan view. As a result, thread A is forcibly pulled by the arm 38.

As a result, at the end of the knot, thread A can be forcibly pulled to tighten the knot. Hereinafter, the position of arm 38 shown in Figure 5 will be referred to as the "third position."

As described above, the thread tension control device 30 according to this embodiment can change the tension applied to thread A depending on the situation when tying. Therefore, it is possible to reduce the load on thread A when not tying, and to remove slack from thread A and strengthen the knot when tying. Furthermore, because the arm 38 is constructed of a rigid body, it is possible to perform control with excellent responsiveness.

The above describes the first embodiment of the present invention, but the present invention is not limited to the above embodiment and can be modified as appropriate within the scope of the technical concept of the invention described in the claims.

For example, in this embodiment, the cam 33 is configured to swing the arm 38 clockwise and counterclockwise when viewed from the bottom by using two protrusions, the first protrusion 35 and the second protrusion 36, but the arm 38 may be configured to swing in the clockwise and counterclockwise directions when viewed from the bottom by using a single protrusion. In other words, the cam 33 does not necessarily have to have two protrusions, and may instead have a single protrusion.

Figure 6(a) shows cam 33A, a first alternative example of cam 33, in a state where the biasing force of kick spring 39 applied to arm 38 and the tension of thread A are balanced. Cam 33A shown in Figure 6(a) differs from cam 33 shown in Figures 2 to 5 in that it does not have second protrusion 36. When using cam 33A to prevent a load from being applied to thread A before tying, as in Figure 3, cam 33A is rotated clockwise when viewed from the bottom, and the first pressing surface 35a presses pin 38b of arm 38. This allows arm 38 to swing to the first position shown in Figure 3.

On the other hand, if you want to forcefully pull thread A at the end of tying, rotate cam 33A counterclockwise from the position shown in Figure 6(a) by nearly 360 degrees as viewed from the bottom, causing the second pressing surface 35b, which is the surface opposite to the first pressing surface 35a of the first protrusion 35, to press against pin 38b of arm 38. This causes arm 38 to swing to the third position shown in Figure 5, allowing the knot of thread A to be tightened.

In addition, in this embodiment, one end of the kick spring 39 is fixed to the arm 38 and the other end of the kick spring 39 is fixed to the motor base 32, but the other end of the kick spring 39 may be fixed to the cam 33 instead of the motor base 32. In this way, by rotating the cam 33, the other end of the kick spring 39 moves, making it possible to change the biasing force of the kick spring 39 acting on the arm 38. Therefore, the tension applied to the thread A during tying can be controlled depending on the ease with which the thread A stretches and contracts, etc.

Specifically, if the tension applied to thread A by kick spring 39 is too great because thread A is relatively difficult to stretch, for example, then cam 33 can be rotated to reduce the biasing force of kick spring 39. On the other hand, if the tension applied to thread A by kick spring 39 is too small because thread A is relatively easy to stretch, for example, then cam 33 can be rotated to increase the biasing force of kick spring 39.

However, if the other end of the kick spring 39 is fixed to the cam 33, when the cam 33 is rotated to press and swing the arm 38, the force of the kick spring 39 causes the arm 38 to move away as the first protrusion 35 or the second protrusion 36 of the cam 33 approaches the pin 38b of the arm 38, making it difficult to accurately align the arm 38 to the first position. To solve this problem, a configuration like the cam 33B shown in Figure 6(b) can be used.

Figure 6(b) shows cam 33B, a second example of cam 33, in which the biasing force of kick spring 39 applied to arm 38 and the tension of thread A are balanced. Cam 33B shown in Figure 6(b) differs from cam 33 shown in Figures 2 to 5 in that it includes a third protrusion 46. In cam 33B, the other end of kick spring 39 is fixed to first protrusion 35. Third protrusion 46 is formed between first protrusion 35 and pin 38b of arm 38, extending substantially to the right from the portion through which motor shaft 31a is inserted. Third protrusion 46 is formed with a third pressing surface 46a facing pin 38b. Third pressing surface 46a is formed at a position closer to pin 38b than first pressing surface 35a of first protrusion 35.

In cam 33B, the distance from pin 38b of arm 38 to third pressing surface 46a is shorter than the distance to first pressing surface 35a. Therefore, when cam 33B is rotated clockwise as viewed from the bottom, third pressing surface 46a can easily come into contact with pin 38b before arm 38 escapes. On the other hand, when cam 33B is rotated counterclockwise as viewed from the bottom, first protrusion 35 moves away from arm 38, increasing the biasing force of kick spring 39. As the biasing force increases, the tension of thread A increases. When thread A reaches a predetermined tension, the angular displacement of arm 38 due to the biasing force of kick spring 39 stops, but the second protrusion 36 presses against pin 38b, swinging arm 38 to the third position shown in Figure 5, allowing thread A to be forcibly pulled.

In addition, a sensor may be provided to measure the tension applied to thread A, and the position of arm 38 may be adjusted based on the measurement value of the sensor. This allows the tension applied to thread A to be controlled to the desired value.

Alternatively, a motor capable of acquiring axial torque may be used as the motor 31, and the position of the arm 38 may be adjusted based on the value of the axial torque acquired by the motor 31. This makes it possible to control the tension applied to the thread A to the desired value. Note that the axial torque acquired by the motor 31 includes not only the tension applied to the thread A but also the biasing force of the kick spring 39. For this reason, it is preferable to provide a sensor that detects the position of the arm 38 so that the position of the end point of the kick spring 39 can be determined using this sensor. This makes it possible to determine changes in the biasing force of the kick spring 39, and therefore the tension applied to the thread A can be calculated by subtracting the biasing force of the kick spring 39 from the axial torque acquired by the motor 31.

Next, a yarn tension control device 50 according to a second embodiment will be described using Figures 7 to 9. The yarn tension control device 50 according to the second embodiment differs from the yarn tension control device 30 according to the first embodiment mainly in that a lifting member 41a is provided on the motor shaft 31a, and that a first cam 53 and a second cam 56 are provided instead of the cam 33. Note that the motor base 32 and yarn guide 37 are not shown in Figures 7 to 9. Furthermore, although the first cam 53, second cam 56, and arm 38 are rotatable or swingable members, the following description will be based on the positions shown in Figures 7 and 9(b).

The lifting member 41a is hollow and has an open end, and is configured to enclose the motor shaft 31a. The cross-sectional shape of the opening of the lifting member 41a is similar to that of the motor shaft 31a, but is not limited thereto. The lifting member 41a is rotatable together with the motor shaft 31a and is movable up and down by a solenoid (not shown) located below the lifting member 41a. The lower end of the lifting member 41a is shaped to be able to mesh with the first cam 53 and the second cam 56. The lower end of the lifting member 41a is polygonal in bottom view, with a larger diameter than the rest of the lifting member 41a, for example, a decagonal to pentagonal shape in bottom view.

The first cam 53 is used to swing the arm 38 and is inserted into the lower end of the lifting member 41a. The first cam 53 is formed in a plate shape and is positioned with its plate surface facing up and down. A protrusion 55 is formed on the first cam 53.

The protrusion 55 extends left rearward from the portion through which the lifting member 41a is inserted to a position where it can act on the pin 38b of the arm 38, and is formed so as to abut against the pin 38b when the first cam 53 rotates. The protrusion 55 is formed with a first pressing surface 55a and a second pressing surface 55b, and when the first cam 53 rotates clockwise as viewed from the bottom, the first pressing surface 55a presses against the pin 38b, and when the first cam 53 rotates counterclockwise as viewed from the bottom, the second pressing surface 55b presses against the pin 38b.

The second cam 56 controls the biasing force of the kick spring 39 and is inserted into the lifting member 41a above the first cam 53. The second cam 56 is formed in a plate shape and is positioned with its plate surface facing up and down. A protrusion 58 is formed on the second cam 56.

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

The lifting member 41a is arranged so that its lower end can move up and down between a position where it engages with the first cam 53 shown in FIG. 8(a) and a position where it engages with the second cam 56 shown in FIG. 8(b). When the lifting member 41a is in 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 in 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 so that it is possible to switch between the first cam 53 and the second cam 56 rotating due to the driving force of the motor 31.

Next, using Figure 9, we will explain the operation of each component of the thread tension control device 50 when controlling the tension of thread A.

As shown in Figure 9(a), before tying, the lifting member 41a is moved to the position shown in Figure 8(a) and the motor 31 is driven to rotate the first cam 53 clockwise when viewed from the bottom, causing the first pressing surface 55a to press the pin 38b of the arm 38. This allows the arm 38 to swing to the first position shown in Figure 3.

As shown in Figure 9(b), during tying, the first cam 53 is rotated counterclockwise as viewed from the bottom until the protrusion 55 does not abut the pin 38b of the arm 38. The arm 38 then swings counterclockwise as viewed from the bottom to the second position shown in Figure 4 due to the biasing force of the kick spring 39, causing the portion of the thread A inserted through the insertion hole 38a of the arm 38 to be pulled by the arm 38. This removes any slack in the thread A that occurs during tying.

At this time, the second cam 56 can be rotated by driving the motor 31 with the lifting member 41a moved to the position shown in Figure 8 (b). This allows the biasing force of the kick spring 39 applied to the arm 38 to be changed, and ultimately allows the tension applied to the thread A when removing slack from the thread A to be controlled.

In this way, by making the cam that presses the arm 38 and the cam to which the other end of the kick spring 39 is fixed separate components, it is possible to independently vary the biasing force of the kick spring 39 and forcibly apply tension to the thread A by pulling the arm 38, thereby achieving both.

As shown in Figure 9(c), when finishing tying the knot, the lifting member 41a is moved to the position shown in Figure 8(a), and the motor 31 is driven to rotate the first cam 53 counterclockwise as viewed from the bottom, causing the protrusion 55 to press against the pin 38b of the arm 38. This allows the arm 38 to swing to the third position shown in Figure 5, thereby tightening the knot of the knot A.

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 modified as appropriate within the scope of the technical concept of the invention described in the claims.

For example, in this embodiment, the lifting member 41a moves up and down using a solenoid or the like to switch whether the first cam 53 or the second cam 56 rotates due to the driving force of the motor 31, but the first cam 53 and the second cam 56 may each move up and down.

Next, a yarn tension control device 60 according to a third embodiment will be described using Figures 10 and 11. The yarn tension control device 60 according to the third embodiment differs from the yarn tension control device 30 according to the first embodiment mainly in that it is equipped with a first cam 63 and a second cam 66 instead of the cam 33, and that it is equipped with a differential gear 69. Note that the motor base 32 and yarn guide 37 are not shown in Figures 10 and 11.

The first cam 63 is used to swing the arm 38 and is formed in the same shape as the first cam 53 of the second embodiment. A pressing surface 65a is formed on the protrusion 65 of the first cam 63, and when the first cam 63 rotates counterclockwise when viewed from the bottom, the pressing surface 65a presses against the pin 38b.

The second cam 66 controls the biasing force of the kick spring 39 and is formed in the same shape as the second cam 56 in the second embodiment. The second cam 66 is fixed to the motor shaft 31a and is configured to rotate around the axis of the motor shaft 31a as the motor shaft 31a rotates. The other end of the kick spring 39 is fixed to the protrusion 68 of the second cam 66.

The first cam 63 is connected to the second cam 66 via a differential gear 69 provided between the first cam 63 and the second cam 66. As a result, the first cam 63 is configured to rotate in the opposite direction to the rotation of the second cam 66 as the second cam 66 rotates due to the driving force of the motor 31.

Next, using Figure 11, we will explain the operation of each component of the thread tension control device 60 when controlling the tension of thread A.

If you want to change the biasing force of the kick spring 39 while tying the line, as shown in Figure 11 (a), by rotating the second cam 66 using the driving force of the motor 31, the position of the other end of the kick spring 39 moves and the biasing force of the kick spring 39 can be changed. Specifically, by rotating the second cam 66 counterclockwise as viewed from the bottom, the second cam 66 moves away from the arm 38, increasing the biasing force of the kick spring 39. On the other hand, by rotating the second cam 66 clockwise as viewed from the bottom, the second cam 66 moves closer to the arm 38, decreasing the biasing force of the kick spring 39.

When it is necessary to forcibly apply tension to thread A at the end of tying, as shown in Figure 11(b), the driving force of motor 31 rotates second cam 66 clockwise as viewed from the bottom, causing first cam 63 to rotate counterclockwise as viewed from the bottom, bringing the pressing surface 65a of protrusion 65 into contact with pin 38b of arm 38. By further rotating first cam 63 counterclockwise as viewed from the bottom, protrusion 65 presses against pin 38b of arm 38, causing arm 38 to further swing counterclockwise as viewed from the bottom. This allows arm 38 to swing to the third position shown in Figure 5, thereby tightening the knot in thread A.

If tension is not desired in thread A before tying, as shown in FIG. 11(c), the first cam 63 is rotated clockwise in bottom view from the position shown in FIG. 11(b) by the driving force of the motor 31. When the first cam 63 rotates clockwise in bottom view, the arm 38 is urged by the force of the kick spring 39 to swing clockwise in bottom view together with the first cam 63 while in contact with the first cam 63. This allows the arm 38 to swing to the first position shown in FIG. 3.

As described above, the yarn tension control devices 30, 50, and 60 according to the first to third embodiments of the present invention are provided in the knotter device 3, but as shown in FIG. 12, they may also be provided in the flat knitting machine 4. Below, we will explain an example in which the yarn tension control devices 30, 50, and 60 are provided in the flat knitting machine 4.

In conventional flat knitting machines, when knitting yarn is inlayed from either the left or right side of the flat knitting machine, the tension is reduced at the end of the knitted fabric far from the yarn tension control device installed near the side of the flat knitting machine when the yarn feeder is reversed. In particular, when a high-rigidity fiber is used as the inlay yarn, the tension applied by the spring cannot keep up with changes in the yarn tension, posing a problem of the inlay yarn having a long distance to travel when the yarn is reversed at the far end of the knitted fabric.

In the present invention, by providing the yarn tension control devices 30, 50, and 60 to the flat knitting machine 4, when inlaying high-rigidity fibers as weft yarns, the arm 38 is swung to the third position shown in Figure 5 when the yarn feeder is reversed at the end of the knitted fabric far from the yarn tension control devices 30, 50, and 60, increasing the tension applied to yarn A. This absorbs tension changes during reversal and prevents the yarn from becoming too long when the weft yarn is reversed at the end of the knitted fabric.

3 Knotter device 4 Flat knitting machine 30, 50, 60 Yarn tension control device 31 Motor 33 Cam 37 Yarn guide 38 Arm 39 Kick spring 53, 63 First cam 56, 66 Second cam 69 Differential gear

Claims (7)

a motor that generates a driving force;
a cam configured to be rotatable by the driving force of the motor;
a pair of thread guides for guiding the thread to a predetermined position;
a spring that generates a biasing force;
an arm that is supported so as to be swingable along an imaginary plane that passes between the pair of yarn guides, has an insertion portion through which the yarn guided by the pair of yarn guides is inserted, and an action portion on which the cam can act, and is biased by the spring in a direction that applies tension to the yarn, and by the action of the cam on the action portion, swings in a direction away from the pair of yarn guides based on a position where the biasing force of the spring and the tension of the yarn are balanced, thereby increasing the tension applied to the yarn;
Equipped with
Thread tension control device. The arm
The action of the cam on the action portion causes the action portion to swing in a direction approaching the pair of yarn guides with the balanced position as a reference, thereby reducing the tension applied to the yarn.
The yarn tension control device according to claim 1. One end of the spring is fixed to the arm, and the other end of the spring is fixed to the cam.
The yarn tension control device according to claim 1 or 2. The cam is
a first cam configured to be able to act on the action portion of the arm, and a second cam to which the other end of the spring is fixed,
The drive force of the motor is configured to be able to switch between rotating the first cam and the second cam.
The yarn tension control device according to claim 3. The cam is
a first cam configured to act on the action portion of the arm, and a second cam to which the other end of the spring is fixed,
one of the first cam and the second cam is fixed to a motor shaft of the motor;
the other of the first cam or the second cam is connected to either the first cam or the second cam via a differential device and is configured to rotate in an opposite direction to either the first cam or the second cam as either the first cam or the second cam rotates.
The yarn tension control device according to claim 3. A knotter device comprising the yarn tension control device according to claim 1 or 2 . A flat knitting machine comprising the yarn tension control device according to claim 1 or 2 .