Yarn tension control device, knotter device and flat knitting machine

Abstract

To provide a yarn tension control device capable of controlling tension applied to a yarn, a knotter device, and a flat-knitting machine.SOLUTION: A yarn tension control device comprises: a motor 31 to generate drive power; a cam 33 constituted so as to be rotatable by the drive power of the motor 31; a pair of yarn guides 37A, 37B to guide a yarn A to a prescribed position; a kick spring 39 to generate energizing force; and an arm that is swingably supported along a virtual plane passing between the pair of yarn guides 37A, 37B, has an insertion hole 38a allowing the yarn A guided by the pair of yarn guides 37A, 37B to be inserted and a pin 38b on which the cam 33 can act, is energized by the kick spring 39 in a direction for applying tension to the yarn A, and increases the tension applied to the yarn A by swinging in a direction to be separated away from the pair of yarn guides 37A, 37B based on a position at which the energizing force of the kick spring 39 is balanced with the tension of the yarn A due to action of the cam 33 to the pin 38b.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a yarn tension control device, and to a technique for a knotter device and a flat knitting machine equipped with the yarn tension control device. [Background technology]

[0002] Conventionally, devices that apply tension to yarns supplied to textile machines by the biasing force of a spring have been known. For example, Patent Document 1 discloses a device that is provided in a knotter device and applies a constant tension to the yarn by the biasing force of a spring. It is also known that flatbed knitting machines are also provided with devices that apply tension to yarns by the biasing force of a spring.

[0003] However, the device disclosed in Patent Document 1 applies a constant tension to the thread even when not tying, which causes problems such as placing an excessive load on the thread. For this reason, a thread tensioning device that can control the tension applied to the thread is desired. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 2614775 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and the problem to be solved by the present invention is to provide a yarn tension control device, a knotter device, and a flat knitting machine that are capable of controlling the tension applied to a yarn. [Means for solving the problem]

[0006] The problem to be solved by the present invention is as described above, and the means for solving this problem will now be described.

[0007] 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 by 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] The knotter device is equipped 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.

[0013] A flat knitting machine 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 prevent the weft yarn from being long when it is inverted at the end of the knitted fabric. [Effects of the Invention]

[0014] The effect of the present invention is that the tension applied to the thread can be controlled. [Brief explanation of the drawings]

[0015] [Figure 1] 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; [Figure 2] FIG. [Figure 3] FIG. 10 is a bottom view of the yarn tension control device before tying the yarn. [Figure 4] FIG. 10 is a bottom view of the yarn tension control device during tying. [Figure 5] FIG. 10 is a bottom view of the yarn tension control device at the end of tying the yarn. [Figure 6] 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. [Figure 7] FIG. 10 is a perspective view of a yarn tension control device according to a second embodiment. [Figure 8] 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. [Figure 9] 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. [Figure 10] FIG. 10 is a front view of a yarn tension control device according to a third embodiment. [Figure 11] 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. [Figure 12] 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. DETAILED DESCRIPTION OF THE INVENTION

[0016] In the following description, the directions indicated by arrows U, D, F, B, L, and R in the drawings are defined as the upward direction, downward direction, forward direction, backward direction, leftward direction, and rightward direction, respectively. In addition, in the drawings, illustration of each component part is omitted as appropriate for simplification of the illustration.

[0017] 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 disposed downstream of the yarn cone 2 in the yarn feeding direction, and the flat knitting machine 4 is disposed downstream of the knotter device 3 in the yarn feeding direction.

[0018] In the flat knitting machine 4, a yarn feeder 5 moves along a needle bed 7 in conjunction with a carriage 6. A large number of knitting needles 8 are arranged in parallel on the needle bed 7, and the knitting needles 8 move forward and backward into needle gaps 9 to draw in a yarn A from the yarn feeder 5 and knit a knitted fabric product C.

[0019] The knotter device 3 splices a yarn A currently being used in the flat knitting machine 4 with a new yarn A wound around a yarn cone 2. The knotter device 3 includes a yarn selection unit 10 and a yarn splicing unit 20.

[0020] The yarn selecting unit 10 is configured to be able to guide a yarn A selected from the multiple yarns A supplied from the yarn cone 2 to the yarn splicing unit 20. The yarn splicing unit 20 is configured to be able to splice the yarn A selected by the yarn selecting unit 10 with the yarn A being used in the flat knitting machine 4. The yarn splicing unit 20 is provided downstream in the yarn feeding direction of the yarn selecting unit 10. A yarn tension control device 30 is provided in the yarn splicing unit 20.

[0021] The configuration of the yarn tension control device 30 will be described below with reference to Figures 2 and 4. Although the cam 33 and the arm 38 are rotatable or swingable members, the following description will be given based on the positions shown in Figures 2 and 4.

[0022] The thread tension control device 30 controls the tension of the thread A when tying a thread. 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.

[0023] The motor 31 generates a driving force. Any motor can be used as the motor 31, but a stepping motor or a 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 axial direction 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).

[0024] The motor base 32 supports the motor 31. The motor base 32 is formed into an appropriate shape capable of supporting the motor 31, and is provided below the motor 31 so that the motor shaft 31a passes through it. The motor base 32 is provided with a pin 32a.

[0025] The pin 32a is provided near the portion where the motor shaft 31a is inserted so as to extend downward from the lower surface of the motor base 32. An end of a kick spring 39, which will be described later, is engaged with the pin 32a.

[0026] 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 provided so as to rotate about 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 vertical direction. A first protrusion 35 and a second protrusion 36 are formed on the cam 33.

[0027] The first protrusion 35 is one of two protrusions that form the generally L-shaped 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 generally 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 is formed with a first pressing surface 35a that faces the pin 38b, and the first pressing surface 35a presses the pin 38b when the cam 33 rotates clockwise in a bottom view.

[0028] The second protrusion 36 is the other of the two protrusions that form the generally L-shaped shape of the cam 33, and acts on a pin 38b of an arm 38 (described later) when the cam 33 rotates counterclockwise in a bottom view. The second protrusion 36 is formed to extend generally 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 protrusion 36 is formed to extend in a direction 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 the pin 38b when the cam 33 rotates counterclockwise in a bottom view.

[0029] The thread guide 37 guides the 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 may be referred to as thread guide 37B. As shown in FIG. 4, an insertion hole 37a is formed at the tip of each thread guide 37, and the thread A supplied from the thread cone 2 is inserted through the insertion hole 37a. The insertion hole 37a of the thread guide 37A and the insertion hole 37a of the thread guide 37B are formed at positions that overlap when viewed from the bottom.

[0030] 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 as to be swingable along an imaginary plane passing between the thread guide 37A and the thread guide 37B. The imaginary plane is a plane intersecting 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.

[0031] 4 is formed so as to pass vertically through the tip of the arm 38, and thread A guided by the thread guide 37 is inserted through the insertion hole 38a. 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.

[0032] The pin 38b is actable by the cam 33. The pin 38b has a cylindrical outer shape and extends from the lower surface of the arm 38 to the same height as the lower surface of the cam 33 or below the lower surface 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 about 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 with each other when the cam 33 rotates.

[0033] The kick spring 39 biases the arm 38. The kick spring 39 is provided between the motor base 32 and the arm 38 so that the motor shaft 31a is 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 as 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.

[0034] 3 to 5, the operation of each component of the yarn tension control device 30 when controlling the tension of the yarn A will be described. The yarn tension control device 30 controls the tension applied to the yarn A when tying the yarn A selected by the yarn selection unit 10 in the yarn splicing unit 20 with the yarn A being used in the flat knitting machine 4. Hereinafter, the period before tying the yarn is referred to as "before tying the yarn," the period during tying the yarn is referred to as "during tying the yarn," and the period when the knot is finally tightened in tying the yarn is referred to as "end of tying the yarn."

[0035] 3, before tying, the motor 31 is driven to rotate the cam 33 clockwise as viewed from the bottom from the position shown in Fig. 4, thereby bringing the first pressing surface 35a of the first protrusion 35 into contact with the pin 38b of the arm 38. By further rotating the cam 33 clockwise as viewed from the bottom, the first protrusion 35 presses 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 position shown in Fig. 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, i.e., in the 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.

[0036] This allows the thread A to be guided to a position where no tension is applied to the thread A. Therefore, it is possible to prevent unnecessary load from being applied to the thread A before the thread is knotted. Hereinafter, the position of the arm 38 shown in Figure 3 will be referred to as the "first position."

[0037] As shown in Fig. 4, during tying, the motor 31 is driven to rotate the cam 33 counterclockwise as viewed from the bottom 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 abuts against 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 to it. 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 Fig. 3. This causes the arm 38 to pull the portion of the thread A inserted through the insertion hole 38a of the arm 38.

[0038] As a result, during tying, the tension of the kick spring 39 applied to the thread A 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."

[0039] As shown in Fig. 5, at the end of tying, the motor 31 is driven to rotate the cam 33 counterclockwise as viewed from the bottom from the position shown in Fig. 4, thereby bringing the second pressing surface 36a of the second protrusion 36 into contact with the pin 38b of the arm 38. By further rotating the cam 33 counterclockwise as viewed from the bottom, the second protrusion 36 presses the pin 38b of the arm 38, causing the arm 38 to swing further counterclockwise as viewed from the bottom from the second position shown in Fig. 4, i.e., in a direction in which the tip of the arm 38 moves away from the insertion holes 37a of the yarn guides 37A and 37B in a plan view. As a result, the yarn A is forcibly pulled by the arm 38.

[0040] As a result, at the end of the knotting, the knot of the thread A can be tightened by forcibly pulling the thread A. Hereinafter, the position of the arm 38 shown in Fig. 5 will be referred to as the "third position."

[0041] As described above, the yarn tension control device 30 according to this embodiment can change the tension applied to the yarn A depending on the situation when tying. Therefore, it is possible to reduce the load on the yarn A when not tying, and to remove slack from the yarn A and tighten the knot of the yarn A when tying. Furthermore, because the arm 38 is made of a rigid body, it is possible to perform control with excellent responsiveness.

[0042] 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 modified as appropriate within the scope of the technical idea of ​​the invention described in the claims.

[0043] For example, in this embodiment, cam 33 is configured to swing arm 38 clockwise and counterclockwise as viewed from the bottom by two protrusions, namely, first protrusion 35 and second protrusion 36, but arm 38 may be swung clockwise and counterclockwise as viewed from the bottom by one protrusion. In other words, cam 33 does not necessarily have to have two protrusions, and may have one protrusion.

[0044] FIG. 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. The cam 33A shown in FIG. 6(a) differs from the cam 33 shown in FIGS. 2 to 5 in that it does not include second protrusion 36. When it is desired to prevent a load from being applied to thread A before tying, cam 33A is rotated clockwise as viewed from the bottom, as shown in FIG. 3, and the first pressing surface 35a presses pin 38b of arm 38. This allows arm 38 to swing to the first position shown in FIG. 3.

[0045] On the other hand, if you want to forcibly pull the thread A at the end of tying, rotate the cam 33A counterclockwise from the position shown in Figure 6(a) by nearly 360° as viewed from the bottom, so that the second pressing surface 35b, which is the surface opposite to the first pressing surface 35a of the first protrusion 35, presses the pin 38b of the arm 38. This causes the arm 38 to swing to the third position shown in Figure 5, allowing the knot of the thread A to be tightened.

[0046] Furthermore, 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, and the biasing force of the kick spring 39 acting on the arm 38 can be changed. Therefore, the tension applied to the thread A during tying can be controlled depending on the ease of stretching of the thread A, etc.

[0047] Specifically, if the tension applied to the thread A by the kick spring 39 is too large because the thread A is relatively difficult to stretch, for example, the cam 33 can be rotated to reduce the biasing force of the kick spring 39. On the other hand, if the tension applied to the thread A by the kick spring 39 is too small because the thread A is relatively easy to stretch, for example, the cam 33 can be rotated to increase the biasing force of the kick spring 39.

[0048] However, when the other end of kick spring 39 is fixed to cam 33, when cam 33 is rotated to press and swing arm 38, as first protrusion 35 or second protrusion 36 of cam 33 approaches pin 38b of arm 38, arm 38 moves away due to the force of kick spring 39, which poses a problem that arm 38 cannot be accurately positioned at the first position. To solve this problem, a configuration like cam 33B shown in Figure 6(b) can be used.

[0049] FIG. 6(b) shows a cam 33B, which is a second example of the cam 33, and illustrates a state in which the biasing force of the kick spring 39 applied to the arm 38 and the tension of the thread A are balanced. The cam 33B shown in FIG. 6(b) differs from the cam 33 shown in FIGS. 2 to 5 in that it includes a third protrusion 46. In the cam 33B, the other end of the kick spring 39 is fixed to the first protrusion 35. The third protrusion 46 is formed between the first protrusion 35 and the pin 38b of the arm 38, extending substantially to the right from the portion through which the motor shaft 31a is inserted. The third protrusion 46 is formed with a third pressing surface 46a that faces the pin 38b. 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.

[0050] In cam 33B, the distance from pin 38b of arm 38 to third pressing surface 46a is shorter than the distance from first pressing surface 35a. Therefore, when cam 33B is rotated clockwise as viewed from the bottom, third pressing surface 46a can be easily brought 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 yarn A increases. When yarn A reaches a predetermined tension, the angular displacement of arm 38 due to the biasing force of kick spring 39 stops, but second protrusion 36 presses pin 38b, causing arm 38 to swing to the third position shown in FIG. 5, thereby forcibly pulling yarn A.

[0051] Furthermore, a sensor may be provided to measure the tension applied to the thread A, and the position of the arm 38 may be adjusted based on the measurement value of the sensor. This allows the tension applied to the thread A to be controlled to a desired value.

[0052] 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 a desired value. 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 by the 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.

[0053] Next, a yarn tension control device 50 according to a second embodiment will be described with reference to Fig. 7 to Fig. 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 the yarn guide 37 are not shown in Fig. 7 to Fig. 9. Furthermore, although the first cam 53, the second cam 56, and the arm 38 are rotatable or swingable members, the following description will be given based on the positions shown in Fig. 7 and Fig. 9(b).

[0054] The lifting member 41a is hollow and has one open end, and is provided to accommodate the motor shaft 31a. The cross-sectional shape of the opening of the lifting member 41a is, for example, 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) provided 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 shaped to have a polygonal shape in bottom view that is larger in diameter than the rest of the lifting member 41a, for example, a decagonal to pentagonal shape in bottom view.

[0055] The first cam 53 is for swinging 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 disposed with the plate surface facing in the vertical direction. A protrusion 55 is formed on the first cam 53.

[0056] Protrusion 55 extends left rearward from the portion through which lifting member 41a is inserted to a position where it can act on pin 38b of arm 38, and is formed so as to come into contact with pin 38b when first cam 53 rotates. Protrusion 55 is formed with a first pressing surface 55a and a second pressing surface 55b, and when first cam 53 rotates clockwise as viewed from the bottom, first pressing surface 55a presses pin 38b, and when first cam 53 rotates counterclockwise as viewed from the bottom, second pressing surface 55b presses pin 38b.

[0057] 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 disposed with its plate surface facing in the vertical direction. A protrusion 58 is formed on the second cam 56.

[0058] The protrusion 58 extends substantially rightward 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.

[0059] The lifting member 41a is provided so as to be movable up and down between a position where its lower end 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 whether the first cam 53 or the second cam 56 rotates by the driving force of the motor 31.

[0060] 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.

[0061] As shown in Fig. 9(a), before tying, the motor 31 is driven with the lifting member 41a moved to the position shown in Fig. 8(a), causing the first cam 53 to rotate clockwise as viewed from the bottom, causing the first pressing surface 55a to press the pin 38b of the arm 38. This causes the arm 38 to swing to the first position shown in Fig. 3.

[0062] 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 come into contact with the pin 38b of the arm 38. Then, the arm 38 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, and the portion of the thread A inserted through the insertion hole 38a of the arm 38 is pulled by the arm 38. This removes slack in the thread A that occurs during tying.

[0063] 8(b), the second cam 56 can be rotated by driving the motor 31. This makes it possible to change the biasing force of the kick spring 39 applied to the arm 38, and in turn to control the tension applied to the yarn A when removing slack from the yarn A.

[0064] 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 make the spring force of the kick spring 39 variable and to forcibly apply tension to the thread A by pulling the arm 38, thereby achieving both.

[0065] 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 the pin 38b of the arm 38. This allows the arm 38 to swing to the third position shown in Figure 5, thereby making it possible to tighten the knot of the yarn A.

[0066] 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 idea of ​​the invention described in the claims.

[0067] For example, in this embodiment, the lifting member 41a is moved up and down by a solenoid or the like to switch whether the first cam 53 or the second cam 56 rotates by the driving force of the motor 31, but the first cam 53 and the second cam 56 may each move up and down.

[0068] Next, a yarn tension control device 60 according to a third embodiment will be described with reference to 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 provided with a first cam 63 and a second cam 66 instead of the cam 33, and that it is provided with a differential gear 69. Note that the motor base 32 and the yarn guide 37 are not shown in Figures 10 and 11.

[0069] 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 as viewed from the bottom, the pressing surface 65a presses the pin 38b.

[0070] The second cam 66 is used to control the biasing force of the kick 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 arranged to rotate about the axis of the motor shaft 31a as the motor shaft 31a rotates. The other end of the kick spring 39 is fixed to a protrusion 68 of the second cam 66.

[0071] 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 direction opposite to the direction in which the second cam 66 rotates as the second cam 66 rotates due to the driving force of the motor 31.

[0072] 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.

[0073] 11(a), when it is desired to change the biasing force of the kick spring 39, the second cam 66 is rotated by the driving force of the motor 31, thereby moving the position of the other end of the kick spring 39 and changing the biasing force of the kick spring 39. Specifically, by rotating the second cam 66 counterclockwise as viewed from the bottom, the second cam 66 moves away from the arm 38, thereby 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, thereby decreasing the biasing force of the kick spring 39.

[0074] When it is desired to forcibly apply tension to the yarn A at the end of tying, as shown in Fig. 11(b), the driving force of the motor 31 rotates the second cam 66 clockwise as viewed from the bottom, thereby rotating the first cam 63 counterclockwise as viewed from the bottom, and bringing the pressing surface 65a of the protrusion 65 into contact with the pin 38b of the arm 38. By further rotating the first cam 63 counterclockwise as viewed from the bottom, the protrusion 65 presses the pin 38b of the arm 38, causing the arm 38 to further swing counterclockwise as viewed from the bottom. This allows the arm 38 to swing to the third position shown in Fig. 5, thereby tightening the knot of the yarn A.

[0075] If tension is not desired to be applied to the thread A before tying, as shown in Fig. 11(c), the first cam 63 is rotated clockwise as viewed from the bottom from the position shown in Fig. 11(b) by the driving force of the motor 31. When the first cam 63 rotates clockwise as viewed from the bottom, the arm 38 is urged by the force of the kick spring 39 to swing clockwise 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.

[0076] 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 knotter device 3, but as shown in Fig. 12, they may also be provided in the flat knitting machine 4. Below, an example in which the yarn tension control devices 30, 50, 60 are provided in the flat knitting machine 4 will be described.

[0077] In conventional flat knitting machines, when inlaying a knitting yarn 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 follow the change in the yarn tension, which poses a problem that the distance over which the inlay yarn extends when the knitted fabric is reversed becomes longer at the end of the knitted fabric far from the yarn tension control device.

[0078] In the present invention, by providing the yarn tension control devices 30, 50, 60 to the flat knitting machine 4, when inlaying a high-rigidity fiber as a weft yarn, when the yarn feeder is reversed at the end of the knitted fabric far from the yarn tension control devices 30, 50, 60, the arm 38 is swung to the third position shown in Figure 5 to increase the tension applied to the yarn A, thereby absorbing the change in tension when the yarn is reversed and preventing the yarn from extending too long when the weft yarn is reversed at the end of the knitted fabric. [Explanation of symbols]

[0079] 3 Knotter device 4 Flat knitting machine 30, 50, 60 Yarn tension control device 31 Motor 33 Cam 37 Thread guide 38 Arm 39 Kick spring 53, 63 First Cam 56, 66 Second Cam 69 Differential Gear

Claims

1. 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.

2. 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.

3. 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.

4. 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.

5. 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.

6. A knotter device comprising the yarn tension control device according to claim 1 or 2.

7. A flat knitting machine comprising the yarn tension control device according to claim 1 or 2.

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