JP6222683B1 - Needle thread feeder for sewing machine - Google Patents

Abstract

To provide a needle thread feeding device for a sewing machine capable of suppressing twist generated in a portion of a needle thread pulled up from a bobbin without applying excessive tension to a needle thread fed out from a bobbin and generating thread breakage. To do. A needle thread 12 fed upward from a vertically arranged bobbin 11 is sent to a sewing machine 15 through a thread hooking guide 13. At this time, the forward rotation motor 25 is driven, and the bobbin 11 is rotated in the forward direction and the forward direction of the needle thread 12 in synchronization with the delivery of the needle thread 12 from the bobbin 11. Therefore, twisting of the rising portion of the needle thread 12 can be suppressed. Further, since the rotation speed of the forward rotation motor 25 is adjusted by the motor controller 24 according to the needle thread remaining amount of the bobbin 12, etc., even if a fine thread is used, the tension that has become a problem with conventional devices is applied to this rising portion. The cause of thread breakage does not occur. [Selection] Figure 1

Description

  The present invention relates to a needle thread feeding device for a sewing machine, and more particularly to a needle thread feeding device for a sewing machine for feeding a needle thread fed from a bobbin to a sewing machine.

In general commercial and industrial sewing machines, a bobbin for needle thread is supported on a support base with its axis line vertical. The needle thread wound around the bobbin is hung on the threading guide directly above and then sent to the sewing machine separated from the support base (bobbin base).
When the needle thread pulled up from such a vertical-type bobbin is sent out to the sewing machine, twist is likely to occur in the needle thread. This is because the bobbin supported by the support base does not basically rotate, and the needle thread itself is fed out while rotating from the top of the bobbin. In particular, when the remaining amount of needle thread is reduced, the number of times the needle thread is twisted tends to increase. This twist causes troubles such as thread breakage and stitch skipping at the time of sewing of the sewing machine, as well as variations in thread tension, leading to deterioration of the quality of the sewing product.

Therefore, conventionally, for example, a “sewing thread feeding device for a sewing machine” disclosed in Patent Document 1 is known which feeds a needle thread from a bobbin to a sewing machine so that twisting does not occur.
The apparatus of Patent Document 1 takes a bobbin on a horizontal mounting shaft connected to an output shaft of a drive motor, passes a needle thread from a bobbin through a thread path formed on an elevating body that is supported in a vertically movable manner, It is comprised so that it may supply to a sewing needle. Further, when the needle thread is pulled in the direction of the sewing needle by the driving of the sewing machine, the detector detects the ascending / descending of the lifting body, and at the time of the detection, the motor is driven to rotate for a predetermined time, and the bobbin is fed out in the needle thread feeding direction ( Rotate in the forward direction. At this time, the surplus portion (surplus yarn) generated in the needle thread fed out from the bobbin that rotates the motor is configured to be stored in a casing-shaped receiving member provided in the elevating body.

As another conventional technique, a “needle thread feeding device for a sewing machine” of Patent Document 2 that rewinds excessively fed needle thread around a bobbin is also known.
The device of Patent Document 2 rotates the support base in a direction opposite to the direction in which the needle thread is fed out from the bobbin, and the support base in which the bobbin is rotatably supported as the needle thread is fed out by driving the sewing machine. And a counter-rotation motor that rewinds the needle thread excessively drawn out from the bobbin to the original bobbin.
During operation of the sewing machine, the support stand is rotated by a counter-rotating motor in a direction opposite to the needle thread feeding direction, so that the needle thread excessively fed from the bobbin is rewound onto the bobbin. Thereby, it is possible to reliably prevent the twisting of the needle thread with a simple configuration of the counter rotation motor and the support base.

JP-A-6-23181 JP2013-153825A

  However, the needle thread feeding device for a sewing machine disclosed in Patent Document 1 has a problem in that the configuration and control are complicated, and the adjustment for preventing excessive yarn from occurring is complicated. Moreover, the needle thread fed out from the bobbin whose axis is horizontal is first supplied to the sewing machine through the yarn path of the lifting body arranged on one side of the bobbin. For this reason, the needle thread fed out from the bobbin is given a predetermined tension by an elevating body that moves up and down. Especially when a thin needle thread or a soft needle thread is used, the thread breaks due to this tension. There was a risk of occurrence.

  Furthermore, in patent document 1, the output shaft of the drive motor which rotates a bobbin was horizontal. Generally, the needle thread is wound around the bobbin by reciprocating between one end and the other end in the length direction of the bobbin many times. Therefore, although the needle thread destination (supporting plate of the lifting body) derived from the bobbin is always constant, the needle thread feeding position on the outer peripheral surface of the bobbin is the length of the bobbin along with the needle thread feeding. Move gradually in the direction. As a result, the force of the needle thread that tries to move the bobbin in the same direction as the moving direction of the feeding position of the needle thread acts on the bobbin that is removably inserted into the horizontal mounting shaft. As a result, if the bobbin is forgotten to be pulled out during sewing operation, the bobbin may fall off the mounting shaft.

  On the other hand, in the needle thread feeding device for sewing machine of Patent Document 2, although the problem of complication of the configuration and control of Patent Document 1 is solved, the vertical bobbin is rotated in the direction opposite to the needle thread feeding direction. For this reason, this tension is likely to increase compared to the case where tension is applied to the needle thread by the elevating body while rotating the motor in the forward direction of Patent Document 1. As a result, the frequency of thread breakage has increased when thin needle threads and soft needle threads are used.

  Therefore, as a result of earnest research, the inventor has twisted that occurs in the portion of the needle thread between the bobbin and the threading guide by the forward rotation motor when the needle thread is unwound upward from the vertical bobbin. If the bobbin is rotated in the forward direction, which is the same as the needle thread feeding direction, at a speed capable of suppressing the needle thread, the needle thread is fed from the bobbin that needs to be tensioned in the lateral direction (horizontal direction). It is found that the twist generated in the needle thread can be suppressed in the middle of being pulled up from the bobbin in the longitudinal direction (vertical direction) without doing the above, and thus the above-described problems are all solved. Was completed.

  That is, the present invention is for a sewing machine that can suppress the twist generated in the portion of the needle thread pulled up from the bobbin without applying excessive tension to the needle thread fed out from the bobbin and causing thread breakage. An object of the present invention is to provide a needle thread feeding device.

  According to the first aspect of the present invention, the needle thread fed upward from the vertically placed bobbin whose axis is vertical is sent to a sewing machine having a sewing needle through a thread hooking guide disposed immediately above the bobbin. In the needle thread feeding device for a sewing machine, the bobbin base on which the bobbin is placed and the bobbin placed on the bobbin base in synchronism with the feeding of the needle thread from the bobbin. A forward rotation motor that rotates in the same forward direction as the direction, and a rotational speed of the forward rotation motor that is capable of suppressing twisting that occurs in a portion of the needle thread between the bobbin and the yarn hooking guide. A needle thread feeding device for a sewing machine provided with a motor controller that adjusts to

Sewing machines are various types of industrial and various types of industrial sewing machines. The number of sewing needles attached to the sewing machine may be one, two, or three or more.
The needle thread feeding device for the sewing machine has a bobbin base, a forward rotation motor, and a motor controller, and feeds the needle thread fed upward from the vertical bobbin to the sewing machine through the thread guide. It is optional if possible.
The material and shape of the bobbin are arbitrary. The bobbin is used in a vertical state in which the axis is vertical. The number of bobbins used is appropriately changed depending on the number of sewing needles used.

The type of needle thread is arbitrary as long as it is for a sewing machine. For example, hemp yarn, cotton yarn, silk yarn, synthetic yarn, yarn for knitting can be employed.
The structure of the thread hook guide is arbitrary as long as the needle thread can be hooked. One needle thread may be hooked or a plurality of needle threads may be hooked. Further, a height adjusting function may be provided in the strut portion of the yarn hooking guide.
The structure of the bobbin base is arbitrary as long as the bobbin can be placed vertically. In addition, as a structure for rotating the bobbin mounted on the bobbin base, for example, a configuration in which the bobbin base itself is rotated by a motor can be employed. In addition, a configuration may be adopted in which only the bobbin mounting shaft on which the bobbin is detachably mounted is rotatably provided on the bobbin base and the motor is rotated.

The type of the forward rotation motor is arbitrary as long as the bobbin placed on the bobbin base can be rotated in the forward direction with respect to the feeding direction of the needle thread. For example, an electric motor or the like can be employed.
Here, “suppression of twisting of the needle yarn” means that the number of times the needle yarn is twisted is smaller than that in the case of the conventional device, including a state where the needle yarn is not twisted.
“Adjusting to a speed at which twisting can be suppressed” here means that the rotation speed of the bobbin by the forward rotation motor by the controller, including the state where there is no twisting of the needle thread, compared to the case of the conventional device, Adjustment to a speed at which the number of times the needle thread is twisted is reduced.
Specifically, when the needle thread is fed out from the outer peripheral surface of the bobbin in accordance with the sewing machine operation, the speed at which the needle thread feeding position from the bobbin makes one rotation on the outer peripheral surface of the bobbin is used as a reference in plan view. This means that the rotation speed of the bobbin is the same as the rotation speed of the bobbin by the forward rotation motor, or that the rotation speed of the bobbin is slower than the reference rotation speed. The feeding position here refers to a position where the needle thread comes off (leaves) from the bobbin in plan view.

Thus, if the controller adjusts the rotation speed of the bobbin by the forward rotation motor to a speed that can suppress the twisting of the needle thread, the feeding position of the fishing line from the bobbin is always circular in the plan view. A certain angular position (for example, the position of “12 (0)” when a circular bobbin is viewed as a clock in plan view), or a certain angular range (for example, when this bobbin is viewed as a clock) (Position from 12 (0) to 15 (3)). In addition, even if the bobbin rotates slightly from the start to the end of the yarn, this “twist” is prevented.
Further, the “needle yarn portion where twisting is suppressed” here refers to a rising portion (lifting portion) of the needle yarn from the bobbin feeding position to the yarn hooking guide.

  According to a second aspect of the present invention, the sewing machine is for two sewing machines having two sewing needles to which two needle threads fed from a pair of bobbins are fed. The needle thread feeding device includes a first sewing thread feeding section for feeding the one needle thread to the one sewing needle through the thread hooking guide and the remaining needle thread to the thread hooking guide. And a second sewing needle thread feeding section for feeding to the remaining sewing needles, and the first sewing needle thread feeding section and the second sewing needle thread feeding section include the bobbin base. The needle thread feeding device for a sewing machine according to claim 1, wherein the forward rotation motor and the motor controller are respectively disposed.

The type of the two-stitch sewing machine is not limited. For example, it may be used for main sewing or decorative sewing.
The first sewing needle thread feeding section and the second sewing needle thread feeding section individually control the feeding of each needle thread fed from the bobbin to the sewing machine.

  According to a third aspect of the present invention, there is provided a video camera that takes a video image of a feeding position of the needle thread that is displaced in the circumferential direction of the bobbin during the operation of the sewing machine, and the motor controller feeds the needle thread. The rotation speed of the forward rotation motor is automatically controlled so that the displacement angle of the position in the circumferential direction of the bobbin is within a preset control target value of the displacement angle. The needle thread feeding device for a sewing machine according to 2.

Various digital cameras can be adopted as the video camera.
The “displacement angle control target value” here is a value indicating an allowable angle at which the needle thread feeding position fluctuates in the circumferential direction of the bobbin during operation of the sewing machine (or within a predetermined time during operation). . The ideal control target value is 0 °, but may be any value from 5 ° to 350 °, for example. If it is less than 5 °, the control accuracy of the needle thread feeding position is too high, and the device cost may increase. On the other hand, if it exceeds 350 °, the control accuracy of the feeding position of the needle thread is too low, and there is a risk that twist will occur at the rising part of the needle thread. A preferable control target value is a value from 10 ° to 90 °. The predetermined time during operation is, for example, 1 second, 1 minute, or 1 hour.

The invention of claim 3 may be configured as follows.
That is,
“With a video camera that takes a video image of the feeding position of the needle thread that is displaced in the circumferential direction of the bobbin during operation of the sewing machine,
The motor controller is
Displacement angle detection means for detecting a displacement angle at which the feed position of the needle thread in the circumferential direction of the bobbin changes within a predetermined time from moving image data captured by the video camera.
A storage unit storing a control target value of the displacement angle;
The displacement angle of the needle thread feeding position obtained by the displacement angle detecting means is compared with the control target value stored in the storage unit, and the displacement angle of the needle thread feeding position is the control target value. A displacement angle determining means for determining whether or not it is within,
Only when the displacement angle determination means determines that the control target value has deviated, the rotational speed of the forward rotation motor is adjusted so that the displacement angle of the needle thread feeding position is within the control target value. Rotational speed control means to control;
The needle thread feeding device for a sewing machine according to claim 1 or 2, further comprising a control unit for controlling them.

  In this way, from the moving image data captured by the video camera, the displacement angle detecting means detects the displacement angle at which the needle thread feeding position in the circumferential direction of the bobbin changes within a predetermined time, and the obtained needle thread feeding is performed. The displacement angle of the position is compared with the control target value stored in the storage unit, and it is determined by the displacement angle determining means whether the displacement angle of the needle thread feeding position is within the control target value, and the determination result is the control target value. If the rotational speed of the bobbin by the forward rotation motor is controlled by the rotational speed control means so that the displacement angle of the needle thread feeding position is within the control target value only when it is determined that it has deviated from From the start to the end of the needle thread feeding, the fishing line feeding position from the bobbin is a certain angle range of the circular bobbin in plan view (for example, “12 (0 when this bobbin is regarded as a watch). ) To 15 (3) ".

According to the first aspect of the present invention, the needle thread fed upward from the bobbin is sequentially sent to the sewing machine through the threading guide disposed immediately above. At this time, the forward rotation motor is driven, and the bobbin placed on the bobbin base is rotated in the same forward direction as the needle thread feeding direction in synchronization with the needle thread feeding from the bobbin. Thereby, the twist which tends to generate | occur | produce in the part of the needle thread between a bobbin and a thread hook guide can be suppressed. As a result, it is possible to prevent deterioration in quality of the sewn product due to the twist.
In addition, the motor controller adjusts the rotation speed of the forward rotation motor between the bobbin and the threading guide of the needle thread according to changes in the remaining amount of needle thread in the bobbin and the thread feed speed to the sewing machine. The speed is adjusted so as to suppress the twist generated in the part. As a result, even if a thin needle thread is used, the portion of the needle thread between the bobbin and the thread hooking guide (rising part) is caused by the tension applied to the needle thread feeding part in the conventional device. No thread breakage occurs.

Furthermore, since the axis of the bobbin is vertical here, during the sewing machine operation, the needle thread feeding position on the outer peripheral surface of the bobbin extends from one end to the other end in the bobbin length direction as the needle thread is fed. Even if the bobbin moves gradually, the bobbin's own weight becomes a weight to prevent the bobbin from falling out, so that there is no possibility that the bobbin falls off from the bobbin base (attachment shaft) as in the case of the conventional device where the axis of the bobbin is horizontal.
Furthermore, in these conventional apparatuses, the feeding direction of the needle thread from the bobbin is the horizontal direction (horizontal direction). For this reason, sagging due to its own weight is likely to occur in the feeding portion of the needle yarn, and twisting or twisting of the needle yarn due to this sagging is likely to occur. Therefore, in each conventional apparatus, in order to eliminate the slack, a predetermined tension is applied to the feeding portion of the needle thread, and this application is an essential constituent requirement of the conventional apparatus. On the other hand, in the present invention, in order to feed the needle thread upward from the outer peripheral surface of the bobbin, it is not necessary to apply such tension that causes thread breakage to the needle thread feeding part.

In particular, according to the second aspect of the present invention, the two needle threads fed out from each bobbin use the corresponding first sewing needle thread feeding section or the second sewing needle thread feeding section. Then, the yarns are fed to the corresponding sewing needles of the two-sewing machine through the threading guides arranged immediately above each bobbin. At that time, each forward rotation motor is driven, and each bobbin is rotated in the same forward direction as the feeding direction of each needle thread in synchronization with the feeding of each needle thread from each bobbin. Thereby, the twist which tends to generate | occur | produce in the part between a corresponding bobbin and a threading guide among each needle thread | yarn can be suppressed separately.
Therefore, for example, when a curve (curved line) is sewn with two sewing needles, the usage amount of the needle thread is larger on the outer peripheral side than on the inner peripheral side. As a result, a change occurs in the feed amount of the needle thread fed from the pair of bobbins. In this case, each forward rotation motor does not perform the same thread feed adjustment, but adjusts the rotation speed according to the difference in the feed amount of each needle thread. The same applies to the difference in the remaining amount of needle thread in each bobbin.

  According to the third aspect of the present invention, during the operation of the sewing machine, a video image is taken by the video camera of the feeding position of the needle thread that is displaced in the circumferential direction of the bobbin. After that, based on the moving image data obtained by the video camera, the motor controller controls the rotation speed of the forward rotation motor so that the displacement angle of the needle thread feeding position is within the preset control target value of the displacement angle. Automatic control. Thereby, the twist which generate | occur | produces in the standup | rising part of the needle thread between a bobbin and a threading guide can be suppressed automatically.

It is a principal part front view which shows the use condition of the sewing machine for business in which the needle thread feeder for sewing machines which concerns on Example 1 of this invention was mounted. It is a front view including the partially expanded plan view which shows the use condition of the needle thread feeding device for sewing machines which concerns on Example 1 of this invention. It is a principal part front view which shows the use condition of the needle thread feeder for sewing machines which concerns on Example 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged longitudinal sectional view of a foot switch that constitutes a part of a needle thread feeding device for a sewing machine according to Embodiment 1 of the present invention. It is a principal part front view which shows the use condition of the sewing machine for 2 sewing business by which the needle thread feeder for sewing machines which concerns on Example 1 of this invention is mounted. It is a block diagram of the electric equipment which comprises a part of needle thread feeder for sewing machines concerning Example 2 of this invention. It is a flow sheet which shows automatic control of the forward rotation motor by the motor controller which constitutes a part of needle thread feeding device for sewing machines concerning Example 2 of this invention.

  Embodiments of the present invention will be specifically described below with reference to the drawings. For convenience of description, the direction described in the specification is the direction in FIG.

  In FIG. 1, 10 is a needle thread feeding device for a sewing machine according to Embodiment 1 of the present invention. This needle thread feeding device for sewing machine 10 is a needle thread fed upward from a bobbin 11 in a vertically placed state where the axis is vertical. The (upper thread) 12 is sent to a sewing machine 15 having a sewing needle 14 through a thread hooking guide 13 disposed immediately above the bobbin 11.

Hereinafter, these components will be specifically described.
The sewing machine 15 is an industrial sewing machine that sews a leather seat seat mounted on an automobile, and is installed on a gate-shaped sewing work table 16. The sewing machine 15 has a horizontally long main body casing 18 as an outer shell in which a sewing machine driving motor 17 and the like are accommodated. One sewing needle 14 that moves up and down is arranged at the lower end of the left side of the main casing 18. Further, on the front side of the main body casing 18, a needle thread 12 is inserted and a balance (not shown) that functions to feed out the needle thread and tighten the needle thread is provided so as to move up and down. The needle thread 12 drawn from the bobbin 11 by the needle thread feeding device 10 for the sewing machine is inserted into the balance via a thread tension guide 13 and a thread tension portion (not shown) on the front side of the main body casing 18, and the sewing needle 14 is passed through. Guided. Here, the needle thread 12 is inserted into the needle hole of the sewing needle 14 and supplied to the sewing mechanism inside the sewing machine 15.
The yarn hooking guide 13 has a support column 19 erected on the right end of the sewing work table 16 and a horizontally long arm portion 20 that is cantilevered on the upper end of the support column 19. A pair of thread paths 21 on which the needle thread 12 fed out from the bobbin 11 is hooked are disposed at the left end portion of the arm portion 20 and the intermediate portion in the length direction. Of the two yarn paths 21, the one on the right side is arranged almost immediately above the bobbin base 22.

Next, the needle thread feeding device 10 for a sewing machine will be described in detail with reference to FIGS.
As shown in FIGS. 1 and 2, the needle thread feeding device 10 for the sewing machine includes a main body stand 23, the bobbin base 22 on which the bobbin 11 is rotatably mounted, and the feeding of the needle thread 12 from the bobbin 11. Synchronously, the forward rotation motor 25 that rotates the bobbin base 22 in the same forward direction as the feeding direction of the needle thread 12, and the rotational speed of the forward rotation motor 25 are set to the bobbin 11 and the thread hooking guide 13 of the needle thread 12. And a motor controller 24 for adjusting the speed to suppress the twist generated in the portion between the two.

The main body stand 23 is formed by connecting a vertical support portion 23a made of a square steel pipe and a horizontal anchor portion 23b in a downward T-shape.
A vertical plate piece 40a joined to the column portion 23a and a horizontal plate piece 40b with a shaft hole formed in the central portion are connected to the right side surface of the upper end portion of the column portion 23a in an angle shape. A bracket 40 is fixed.
A forward rotation motor 25 having an output shaft 25a inserted through the shaft hole is fixed to the lower surface of the horizontal plate piece 40b. The center portion of the round dish-shaped bobbin base 22 is fixed to the distal end portion of the output shaft 25a via a coupling C.

A circular sponge sheet (not shown) is attached to the upper surface of the bobbin base 22 to prevent the bobbin 11 from slipping. A mounting shaft 22 a into which the cylindrical core 11 a of the bobbin 11 is inserted projects from the center of the upper surface of the bobbin base 22.
A motor controller 24 is fixed to the right side surface near the upper end of the main body stand 23. The motor controller 24 has a control panel inside the casing 24a, and a dial switch (knob) N for steplessly adjusting the rotational speed of the forward rotation motor 25 is provided on the front surface of the casing 24a. .

As shown in FIGS. 3 and 4, a sewing machine 15 and a motor controller 24 are electrically connected to the floor of the internal space of the sewing work table 16 to synchronize the sewing machine drive motor 17 and the forward rotation motor 25. A foot switch 26 for adjusting the output steplessly is placed.
The foot switch 26 has a vertically long rectangular substrate 27, and a laterally long rectangular bowl-shaped sensor case 28 with the opening side facing downward is projected from the tip of the substrate 27. A base end portion (upper end portion) of the proximity sensor 29 is fixed to the center portion of the upper plate of the sensor case 28 in a state where the main body portion is housed in the upper space of the sensor case 28.

In addition, a horizontally long rectangular opening 28 a is formed in the lower part of one side plate (a hinge side described later) of the sensor case 28. Through the opening 28a, the tip of the vertically long rectangular operation pedal 30 is housed in the lower space of the sensor case 28 so as to be movable up and down. A base end portion of the operation pedal 30 is connected to a base end portion of the substrate 27 through a hinge 31 in which a coil spring (not shown) that biases the operation pedal 30 upward is incorporated so as to be vertically rotatable.
Therefore, when the operation pedal 30 is depressed against the spring force of the coil spring, the tip of the operation pedal 30 is separated downward from the proximity sensor 29 by the amount of depression. A signal (an output signal of 0V to 24V) corresponding to the separation distance is transmitted from the foot switch 26 to each control unit of the sewing machine 15 and the motor controller 24. As a result, the sewing machine drive motor 17 and the forward rotation motor 25 are synchronously driven with an output corresponding to the depression amount of the operation pedal 30.

  The adjustment of the feed speed (feed amount) of the needle thread 12 to the sewing machine 15 by the sewing machine drive motor 17 and the forward rotation speed of the bobbin 11 by the forward rotation motor 25 is performed before the actual sewing. 15 may be performed when performing a test operation. As a specific adjustment method, when the operation pedal 30 of the foot switch 26 is depressed by a predetermined amount during the test operation, the feeding position a of the needle thread 12 from the bobbin 11 is along the outer peripheral surface of the bobbin 11. The rotation speed of the forward rotation motor 25 is adjusted so as not to go around.

Next, with reference to FIGS. 1-4, the sewing operation | work of the leather seat seat for motor vehicles performed using the needle thread feeder 10 for sewing machines which concerns on Example 1 of this invention is demonstrated.
As shown in FIGS. 1 to 4, when the operation pedal 30 of the foot switch 26 is stepped against the spring force of the coil spring, the sewing machine drive motor 17 and the forward rotation motor 25 are depressed by the operation pedal 30. Synchronous drive with output according to.
The needle thread 12 fed upward from the bobbin 11 is sequentially hooked on the thread path 21 of the thread hooking guide 13 disposed immediately above and sent to the sewing machine 15. At this time, the forward rotation motor 25 is driven to synchronize with the feeding of the needle thread 12 from the bobbin 11 and to move the bobbin 11 at a predetermined speed integrally with the bobbin base 22 in the same forward direction as the feeding direction of the needle thread 12. Rotate.

That is, the motor controller 24 adjusts the rotation speed of the forward rotation motor 25 to a speed at which the twist generated in the portion of the needle thread 12 between the bobbin 11 and the yarn hooking guide 13 can be suppressed. 11 is rotated. Specifically, when the needle thread 12 is fed out from the outer peripheral surface of the bobbin 11 in accordance with the sewing machine operation, the feeding position (feeding point) a of the needle thread 12 from the bobbin 11 is set on the outer peripheral surface of the bobbin 11 in plan view. Based on the speed of one rotation, the reference rotation speed and the speed at which the bobbin 12 makes one rotation by the forward rotation motor 25 are the same (ideal adjustment), or the rotation speed of the bobbin 12 from this reference rotation speed. Adjust so that is slower (simple adjustment).
Thus, if the controller 24 adjusts the rotation speed of the bobbin 11 by the forward rotation motor 25 to a speed at which the twist of the needle thread 12 can be suppressed, the feeding position of the fishing line 12 from the bobbin 11 is always flat. A certain angular position of the circular bobbin 12 when viewed (for example, a position of “9 o'clock when the circular bobbin 12 is viewed as a clock when viewed in plan), or a certain angular range (for example, the bobbin 12 is It is maintained in the angle range 90 ° of “7:30 to 10:30” as viewed from a watch (partial enlarged view of FIG. 2).
Thereby, the twist which is going to generate | occur | produce in the part of the needle thread 12 between the bobbin 11 and the thread hook guide 13 can be suppressed. As a result, it is possible to prevent the occurrence of yarn breakage, stitch skipping, and variation in yarn tension due to the twist, thereby preventing deterioration of the seat seat quality.

  Further, during the sewing operation, for example, when the remaining amount of the needle thread 12 in the bobbin 11 or the feed speed of the needle thread 12 to the sewing machine 15 changes, or when the bobbin 11 is replaced, the material and thickness of the needle thread 12 are changed. Is changed, the balance between the feeding of the needle thread 12 from the bobbin 11 and the forward rotation of the bobbin 11 by the forward rotation motor 25 is lost. At that time, the dial switch N of the motor controller 24 is rotated by a predetermined amount in a predetermined direction so that the good balance state is restored, and the forward rotation motor 25 is rotated at a higher speed, or conversely, the low speed is decreased. Rotate. As a result, even when a thin needle thread 12 or a soft needle thread 12 is used, the portion of the needle thread 12 between the bobbin 11 and the thread hooking guide 13 (the rising portion) has a needle thread 12 in the conventional apparatus. No thread breakage occurs due to the tension applied to the unwinding part.

  Further, here, since the axis of the bobbin 11 is vertical and the feeding direction of the needle thread 12 is upward (longitudinal direction), when the sewing machine 15 is operated, the destination of the needle thread 12 led out from the bobbin 11 is fixed position. The advancing position a of the needle thread 12 on the outer peripheral surface of the bobbin 11 is gradually moved from one end to the other end in the length direction of the bobbin 11 as the needle thread 12 is fed. Even in this case, since the bobbin 11 becomes a weight, the bobbin 11 does not fall off from the bobbin base 22 (attachment shaft thereof) as in the case of the conventional device in which the axis of the bobbin 11 is horizontal.

  Furthermore, in the case of these conventional devices, since the feeding direction of the needle thread 12 from the bobbin 11 is the horizontal direction (horizontal direction), sagging due to the weight of the thread occurs in the feeding part of the needle thread 12. The needle thread 12 was easily twisted or twisted due to this sagging. Therefore, in these conventional apparatuses, a predetermined tension is applied to the feeding portion of the needle thread 12 in order to eliminate sagging. In other words, this tension application is an essential component of the conventional apparatus. On the other hand, in the needle thread feeding device 10 for the sewing machine according to the first embodiment, the axis of the bobbin 11 is vertical and the needle thread 12 is fed upward from the outer peripheral surface of the bobbin 11. The tension to be applied may not be applied to the feeding portion of the needle thread 12.

Here, the general sewing machine 15 having one sewing needle 14 is employed here. However, the sewing machine 14 is not limited to this. For example, the sewing machine 15A for two sewing machines to which two sewing needles 14A and 14B are attached is used. You may employ | adopt (FIG. 5). In this case, two needle threads 12A and 12B fed from the pair of bobbins 11A and 11B are supplied to the sewing needles 14A and 14B, respectively.
Correspondingly, the sewing machine needle thread feeding device 10A includes a first sewing machine needle thread feeding section 60A for feeding one needle thread 12A to the one sewing needle 14A via the thread hooking guide 13, and the remaining sewing thread. The sewing machine includes a second sewing machine needle thread feed section 60B that feeds the needle thread 12B to the remaining sewing needle 14B through the thread hooking guide 13. A bobbin base 22, forward rotation motors 25A and 25B, and a motor controller 24 are disposed in the first sewing needle thread feeding section 60A and the second sewing needle thread feeding section 60B.

Therefore, the two needle threads 11A and 11B fed out from the bobbins 12A and 12B use the corresponding first sewing needle thread feeding section 60A or the second sewing needle thread feeding section 60B, and each bobbin The yarns are fed to the corresponding sewing needles 14A and 14B of the two-stitch sewing machine 15A through the thread hooking guide 13 arranged immediately above 12A and 12B. At that time, each forward rotation motor 25A, 25B is driven, and each bobbin in the same forward direction as the feeding direction of each needle thread 11A, 11B is synchronized with the feeding of each needle thread 11A, 11B from each bobbin 12A, 12B. 12A and 12B are rotated. Thereby, the twist which tends to generate | occur | produce in the part between corresponding bobbin 12A, 12B and the thread hooking guide 13 among each needle thread 11A, 11B can be suppressed separately.
For this reason, for example, when a leather seat is curved (curved) with two sewing needles 14A and 14B, the usage amount of the needle thread 11A (11B) is larger on the outer peripheral side than on the inner peripheral side. As a result, a change occurs in the feed amount of the needle threads 11A and 11B fed from the pair of bobbins 12A and 12B. In this case, each of the forward rotation motors 25A and 25B does not perform the same thread feed adjustment, but adjusts the rotational speed according to the difference in the feed amount of each needle thread 11A and 11B. The same applies to the difference in the remaining amount of the needle threads 11A and 11B in the bobbins 12A and 12B.

Next, a needle thread feeding device for a sewing machine according to Embodiment 2 of the present invention will be described with reference to FIGS.
As shown in the block diagram of FIG. 6, the feature of the needle thread feeding device 10B for the sewing machine according to the second embodiment of the present invention is that the feeding position of the needle thread 12 displaced in the circumferential direction of the bobbin 11 during the operation of the sewing machine 15 is as follows. The motor controller 24 has a video camera 50 that takes a video image of a, and the motor controller 24 sets the displacement angle θ in the circumferential direction of the bobbin 11 at the feeding position a of the needle thread 12 within the control target value of the preset displacement angle θ. Thus, the rotational speed of the forward rotation motor 25 is automatically controlled.

Hereinafter, these components will be described in detail.
The video camera 50 is a digital type, and is fixed to a portion directly above the bobbin base 22 in the thread hook guide 13. During the operation of the sewing machine 15, the video camera 50 always takes a video image of the feeding position “a” of the needle thread 12 in the circumferential direction of the bobbin 11 (see the partially enlarged view of FIG. 1).
Further, the motor controller 24 detects, from the moving image data captured by the video camera 50, a displacement angle detection means 51 for detecting a displacement angle θ at which the feeding position a of the needle thread 12 in the circumferential direction of the bobbin 11 changes within a predetermined time. And a storage unit 52 in which the control target value (90 ° in this case) of the displacement angle θ is stored, the displacement angle θ of the feed position a of the needle thread 12 obtained by the displacement angle detection means 51, and the storage unit 52. The displacement angle determination means 53 and the displacement angle determination means 53 that deviate from the control target value by comparing the stored control target value and determining whether the displacement angle θ of the feeding position a of the needle thread 12 is within the control target value. The rotational speed control means 54 for controlling the rotational speed of the forward rotation motor 25 so that the displacement angle θ of the feeding position a of the needle thread 12 is within the control target value only when it is determined that And a control unit 55 for controlling.

The displacement angle detection means 51 is a displacement angle detection circuit that detects, from the moving image data of the video camera 50, a displacement angle θ at which the feeding position a of the needle thread 12 in the circumferential direction of the bobbin 11 changes within a predetermined time. The “predetermined time” here is 10 seconds. Of course, it is not limited to this. For example, it may be 1 second or 1 minute.
The storage unit 52 is a RAM (Random access memory) in which a control target value of the displacement angle θ is stored in a readable and writable manner. The control target value here is 30 °. A ROM (Read Only Memory) may be used instead of the RAM.

The displacement angle determination means 53 compares the displacement angle θ of the needle thread 12 at the feeding position a with the control target value of the storage unit 52 to determine whether the displacement angle θ of the needle thread 12 at the feeding position a is within the control target value. This is a displacement angle determination circuit.
Further, when the displacement angle determination unit 53 determines that the displacement angle determination unit 53 is not within the control target value, the rotation speed control unit 54 sequentially increases the displacement angle θ of the needle thread 12 at the feeding position a within the control target value. 2 is a rotation speed control circuit that controls the rotation speed of the rotation motor 25.
Furthermore, the control unit 55 has a central processing unit (CPU) that comprehensively controls these electric devices.

Next, with reference to the flow sheet of FIG. 7, the sewing operation of the leather seat seat for automobiles performed using the needle thread feeding device 10B for the sewing machine according to Embodiment 2 of the present invention will be described.
First, during operation of the sewing machine 15, the video camera 50 takes a video image of the feeding position a of the needle thread 12 that is displaced in the circumferential direction of the bobbin 11.
After that, based on moving image data of 10 seconds arbitrarily extracted during the imaging time, the angle (displacement angle θ) when the feeding position a of the needle thread 12 is farthest in the circumferential direction of the bobbin 11 is detected as the displacement angle. Detected by means 51.

Next, the displacement angle determination unit 53 compares the “displacement angle θ of the feed position a of the needle thread 12” detected by the displacement angle detection unit 51 with the “control target value” stored in the storage unit 52. It is determined whether the displacement angle θ of the feeding position a of the needle thread 12 is within the control target value (partial enlarged view of FIG. 2).
As a result of the determination, if the displacement angle θ is within 90 ° of the control target value, the current sewing operation is continued. On the other hand, when the angle deviates from 90 °, the rotational speed of the forward rotation motor 25 is increased or decreased as appropriate based on a command from the control unit 55 so that the displacement angle θ is within the control target value. And automatically control. Thereby, the twist which generate | occur | produces in the standup | rising part of the needle thread 12 between the bobbin 11 and the thread hooking guide 13 can be suppressed automatically. Here, since the displacement angle θ was 45 °, control was performed to continue the current sewing operation.
Other configurations, operations, and effects are in a range that can be inferred from the first embodiment, and thus description thereof is omitted.

  The present invention is useful as a needle thread feeding technique for a sewing machine that feeds a needle thread fed from a bobbin to a sewing machine.

10, 10A, 10B Sewing thread feeder for sewing machine,
11, 11A, 11B bobbins,
12, 12A, 12B Needle thread,
13 Thread guide,
14, 14A, 14B Sewing needle,
15 Sewing machine,
15A sewing machine for two stitches,
22 bobbin stand,
24 motor controller,
25, 25A, 25B forward rotation motor,
50 video cameras,
60A First needle thread feed section for sewing machine,
60B Second needle thread feeder for sewing machine.

Claims (3)

In the needle thread feeding device for a sewing machine, the needle thread fed upward from the bobbin in the vertical state in which the axis line is vertical is sent to a sewing machine having a sewing needle through a threading guide arranged immediately above the bobbin.
A bobbin base on which the bobbin is placed;
A forward rotation motor that rotates the bobbin placed on the bobbin base in the same forward direction as the feeding direction of the needle thread in synchronization with the feeding of the needle thread from the bobbin;
A needle thread for a sewing machine comprising: a motor controller that adjusts the rotational speed of the forward rotation motor to a speed capable of suppressing twisting occurring in a portion of the needle thread between the bobbin and the yarn hooking guide. Feeder. The sewing machine is for two stitches having two sewing needles to which two needle threads fed from a pair of bobbins are fed,
The sewing needle thread feeding device includes a first sewing thread feeding section that feeds one of the needle threads to one of the sewing needles through the thread hooking guide, and the remaining needle thread. A second sewing thread feed section for feeding to the remaining sewing needles through the hanging guide,
2. The bobbin base, the forward rotation motor, and the motor controller are respectively disposed in the first sewing needle thread feeding section and the second sewing needle thread feeding section. Needle thread feeder for sewing machines. A video camera that takes a video image of the feed position of the needle thread displaced in the circumferential direction of the bobbin during operation of the sewing machine;
The motor controller automatically adjusts the rotational speed of the forward rotation motor so that a displacement angle of the needle thread feeding position imaged by the video camera is within a preset control target value of the displacement angle. The needle thread feeding device for a sewing machine according to claim 1 or 2, which is to be controlled.

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