JPH06335584A - Thread take-up lever device of sewing machine - Google Patents

Abstract

PURPOSE:To provide a thread take-up lever device of a sewing machine, which can change locally and arbitrarily a thread take-up curve of a thread take-up lever, can execute an optimal transfer-out of a needle thread, and can execute a proper sewing work. CONSTITUTION:In the inside of a main body case 1 of a sewing machine, the upper shaft 12 is housed so that it can be driven to rotate freely, and on the front side of the main body case 1, a thread take-up lever 2 which is oscillated vertically by a rotation of the upper shaft 12 and allows a prescribed needle thread to execute a transfer-out operation is disposed, a tension thread guard 32 positioned on a middle part of a thread route on the front of the main body case 1 is formed freely reciprocatably in the horizontal direction, and a transfer means for transferring a rotation of the upper shaft 12 to this tension thread guard 32 and operating the tension thread guard 32 is disposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance device of a sewing machine, and more particularly, it is capable of swinging up and down by rotational driving of an upper shaft, and for performing a predetermined upper thread feeding and pulling operation with respect to a sewing needle. The sewing machine balance device.

[0002]

2. Description of the Related Art Generally, in a sewing machine, an upper shaft disposed inside a main body case is rotated, and a balance is vertically swung through a balance transmission mechanism such as a link mechanism. By reciprocating the attached needle bar up and down, a sewing object is sewn. The balance device functions to feed the upper thread in accordance with the consumption of the lower thread by the hook, pull up the upper thread when the lower thread comes out of the hook, and loosen the thread.

FIG. 7 shows such a conventional general sewing machine. A balance 2 is arranged on the front side of a main body case 1 so as to be vertically swingable, and the inside of the main body case 1 is shown. An upper shaft (not shown) for oscillating the balance 2 up and down via a link mechanism or the like is rotatably mounted on the. Further, inside one side of the main body case 1, a needle bar 3 that extends in the vertical direction and is reciprocally moved up and down through the link mechanism or the like is provided, and a lower end portion of the needle bar 3 is provided. Has a needle 4 attached. Further, on the needle 4 portion below the main body case 1, there is attached a cloth presser 6 for moving up and down by a lever 5 to press a sewing object on a predetermined sewing base.

Further, on the upper front side of the main body case 1,
A first thread tensioner 8 for guiding the upper thread 7 from a predetermined thread supply source with a predetermined tension is arranged, and a second thread tensioner 9 is arranged below the front side of the main body case 1. ing.
Further, thread guides 10a and 10b are provided on the front side of the main body case 1 in the thread path between the second thread tension regulator 9 and the thread balance 2 and the thread path between the thread balance 2 and the needle 4, respectively. The thread guides 10a and 10b are tightened and fixed to the main body case 1 by screws 11, and the thread guides 10a and 10b can be adjusted to desired positions by loosening the screws 11 and moving them to the left and right. .

In such a conventional sewing machine, first, the first thread tension regulator 8, the second thread tension regulator 9, and the thread guide 10 are first described.
a, a predetermined upper thread 7 is guided in a path that sequentially passes through the thread passing hole of the balance 2, the thread guide 10b, and the upper thread 7 is inserted into the needle hole of the needle 4. Further, a desired material to be sewn is placed on the sewing table, and the lever 5 is operated to lower the cloth presser 6 to press the material to be sewn.

In this state, by rotating the upper shaft and operating a link mechanism or the like, the balance 2 is swung up and down and the needle bar 3 is reciprocated up and down to sew the needle 4. A desired sewing operation is performed by piercing the material to be sewn on the table and using the upper thread 7 and a lower thread (not shown) which is fed out by a hook arranged on the lower surface side of the sewing table.

In such a conventional sewing machine balance apparatus, the amount of extension of the upper thread 7 of the balance during the sewing operation is specified by the relationship between the vertical movement of the balance 2 and the upper thread path. The characteristics of the operation of the simple balance 2 can be represented as a thread take-up curve of the balance, as shown by the solid line in FIG. Similarly, the amount of bobbin thread unwinding at the time of sewing operation is specified by the operation of the hook, and the characteristic due to the operation of the balance 2 is shown in FIG.
Can be represented as a thread take-up curve of a shuttle, as indicated by a broken line in FIG. The relationship between these thread take-up curves is extremely important for determining the characteristics such as the feeding of the upper thread 7 during the sewing operation.

[0008]

However, in the conventional balance device for the sewing machine, the thread guides 10a and 10b are used.
The needle thread path can be changed by adjusting the position of the thread guide, and the thread take-up curve of the thread take-up can be changed by adjusting the position of the thread guides 10a and 10b, but the position of the thread guides 10a and 10b can be adjusted. However, there is a problem in that the thread take-up curve of the balance is simply shifted to either side as a whole, and the thread take-up curve of the thread balance cannot be locally changed. Therefore, a desired take-up thread take-up curve cannot be obtained, and the take-up amount by the take-up balance 2 cannot be increased or decreased in an arbitrary state. Therefore, the optimum needle thread 7 corresponding to the take-up amount of the shuttle can be obtained. There is a problem that an operation such as feeding out cannot be performed and an appropriate sewing operation cannot be performed.

The present invention has been made in view of the above points, and the thread take-up curve of the balance can be locally and arbitrarily changed, the upper thread can be optimally paid out, and an appropriate sewing operation is performed. It is an object of the present invention to provide a balance device for a sewing machine that can be used.

[0010]

[Means for Solving the Problems] In order to achieve the above object, a balance device for a sewing machine according to a first aspect of the present invention comprises a main body case of a sewing machine, a needle bar having a lower end portion with a needle attached to the inside of the main body case of the sewing machine. An upper shaft for reciprocating movement is rotatably housed, and a balance for inserting an upper thread in the middle of the thread path is swingably arranged vertically on the front side of the main body case. In a balance device of a sewing machine, which is connected to a balance through a transmission mechanism, and the upper shaft is oscillated up and down by the rotational drive of the upper shaft to perform the upper thread feeding operation, A yarn guide is provided which is located in the middle of the yarn path on the front surface and is movable so that the rotational movement of the upper shaft is transmitted by a transmission means to change the yarn path. It is a thing.

According to a second aspect of the present invention, an upper shaft for vertically reciprocating a needle bar having a needle attached to a lower end thereof is housed inside a main body case of the sewing machine so as to be rotatable and driven. A balance is provided on the front side of the main body case, through which the upper thread in the middle of the thread path is inserted so as to be vertically swingable, and the upper shaft and the balance are connected via a transmission mechanism to rotate the upper shaft. In a balance device of a sewing machine which is configured to swing the balance up and down by drive to perform an upper yarn feeding operation, the upper shaft is located in the middle of the yarn path on the front surface of the main body case. It is characterized in that an auxiliary balance is arranged so that it can be swung up and down so that the yarn path is changed by transmitting the rotational movement of the above-mentioned by the transmission means.

[0012]

According to the sewing machine balance device of the invention described in claim 1, the upper thread is driven to rotate and the thread guide is operated, whereby the thread path of the upper thread is synchronized with the swing motion of the thread balance. The thread take-up curve by the balance can be locally changed.
Further, according to the invention described in claim 2, the auxiliary thread balance is oscillated by the rotation of the upper shaft to change the yarn path to change the yarn take-up curve. Since it can be locally changed arbitrarily, it is possible to make an arbitrary setting such as increasing it when the yarn feeding amount is insufficient or decreasing it when the yarn is excessively supplied. The feeding operation can be performed, and an appropriate sewing operation can be performed.

[0013]

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

1 to 3 show an embodiment of a balance device for a sewing machine according to the present invention. Inside a main body case 1, an upper shaft 12 which is rotationally driven by a drive mechanism (not shown).
Is rotatably supported by a bearing 13, and a counterweight 14 forming a cam is fixed to one end of the upper shaft 12. A cam hole 15 is formed at an eccentric position of the counterweight 14 with respect to the upper shaft 12.
No. 4 cam hole 15 has shaft 16 of needle bar crank 16
a is fixed. Further, the shaft 16a of the needle bar crank 16 is rotatably attached to a base end of a balance 2 having a substantially V shape and a tip end protruding from the front surface of the main body case 1. A threading hole 17 for inserting a predetermined upper thread 7 is formed at the tip of the balance 2.

A rotary shaft 1 is provided at a midway portion of the balance 2.
The balance crank 19 which is rotatable around 8 is connected to the tip end thereof, and the balance 2 and the balance crank 19 constitute a predetermined link mechanism.

Further, an upper end portion of a needle bar crank rod 20 is connected to the needle bar crank 16, and a lower end portion of the needle bar crank rod 20 is vertically reciprocally movable and is illustrated at a lower end portion. A needle bar 3 to which a needle is fixed is connected. Then, by rotating the upper shaft 12, the balance weight 14 is driven to rotate, which causes the balance 2 to swing up and down, and via the needle bar crank 16 and the needle bar crank rod 20. The needle bar 3
It is designed to reciprocate up and down.

A cylindrical cam 21 is mounted in the middle of the upper shaft 12, and a cam groove 22 is formed on the outer circumference of the cylindrical cam 21. A mounting base 23 having a flat plate shape is fixed to the front surface side of the main body case 1, and the lower end portion of the mounting base 23 has the cylindrical cam 2
The holding surface 24 is bent to the lower surface side of 1. A swing plate 25 is attached to the lower surface side of the holding surface 24 so as to be swingable around a pin 26, and the base end portion of the swing plate 25 is provided in the cam groove 22 of the cylindrical cam 21. The driven pin 27 to be engaged is fixed. Further, an engaging groove 28 having a substantially U shape is formed at the tip of the swing plate 25.

The slide plate 2 is mounted on the mount 23.
9 is attached by a step screw 30 so as to be slidable in the lateral direction in FIG. 1, and an engaging pin 31 engaged with an engaging groove 28 of the rocking plate 25 is projectingly provided on the slide plate 29. ing. Further, a thread guide 10 for guiding the upper thread 7 is fixed to the tip of the slide plate 29,
A first thread guide 32 as a thread guide through which the upper thread 7 is inserted is formed at the tip of the thread guide 10. Then, the cylindrical cam 21 is rotationally driven by the rotation of the upper shaft 12, whereby the driven pin 27 moves along the cam groove 22, and the thread guide table 10 is moved through the swing plate 25 and the slide plate 29. Is reciprocated right and left.

Further, a first thread tension device 8 is arranged above the front surface of the main body case 1, and a second thread tension device 8 is provided on the front surface of the main body case 1 below the thread guide base 10. A container 9 is provided. A second thread guide 33 is attached to the front surface of the main body case 1 at a position symmetrical to the first thread guide 32 with respect to the balance 2, and the predetermined upper thread 7 is attached to the first thread tensioner. The needle 8 of the needle bar 3 is sequentially guided through the device 8, the second thread tension device 9, the first thread guide 32, the thread passing hole 17 of the balance 2, and the second thread guide 33, respectively. There is.

The cylindrical cam 21, the cam groove 22, the mount 23, the holding surface 24, the swing plate 25, the pin 26, the driven pin 27, the engaging groove 28, the slide plate 29, the engaging pin 31 and the like are used for transmission. It is designed to constitute a means.

Next, the operation of this embodiment will be described.

In the present embodiment, first, a path is formed through the first thread tension regulator 8, the second thread tension regulator 9, the first thread guide 32, the threading hole 17 of the balance 2, and the second thread guide 33 in this order. A predetermined upper thread 7 is guided and the upper thread 7 is inserted through the needle hole of the needle.

By rotating the upper shaft 12 in this state, the counterweight 14 is rotationally driven. Along with this, the cam hole 15 of the counterweight 14 is eccentric to the upper shaft 12 and rotationally driven. Therefore, the balance 2 is swung up and down, and the upper thread 7 passing through the threading hole 17 of the balance 2 is fed out and pulled up. Further, the rotation of the cam hole 15 drives the needle bar crank 16 to rotate, and the needle bar 3 reciprocates up and down via the needle bar crank rod 20, thereby piercing the needle into a predetermined sewing object. A desired sewing operation is performed by the upper thread 7 inserted into the needle hole of the needle and the lower thread which is fed out by the shuttle.

On the other hand, when the upper shaft 12 is rotationally driven, the cylindrical cam 21 is rotationally driven, and the driven pin 27 is moved along the cam groove 22, whereby the swing plate 25 is moved to the pin 26.
The slide plate 29 is horizontally swung via the engaging pin 31 engaged with the engaging groove 28 of the swing plate 25, and the yarn guide base 10, that is, the first yarn guide 3
2 is reciprocated left and right. The reciprocating operation of the first yarn guide 32 is performed in synchronization with the vertical movement of the balance 2. The operation of the first yarn guide 32 causes the upper yarn 7 to move.
Since the path of 1 changes according to the vertical movement of the thread take-up 2, the thread take-up curve by the thread take-up 2 can be changed as shown in FIG. In this case, for example,
By arbitrarily setting the stroke of the slide plate 29 or the shape of the cam groove 22 of the cylindrical cam 21, the thread take-up curve of the thread balance 2 can be arbitrarily changed.

Therefore, in the present embodiment, the thread take-up curve of the balance 2 can be arbitrarily changed by reciprocally moving the first thread guide 32 to change the upper thread path. Can be increased when the shortage is insufficient, and can be decreased when the upper thread 7 is excessively supplied, and the upper thread 7 can be optimally fed out by the balance 2, and an appropriate sewing operation can be performed. Can be done.

5 and 6 show another embodiment of the present invention, in which a shaft support plate 34 is erected on the lower side of the front side of the main body case 1, and the shaft support plate 34 is provided. The rotary shaft 35 and the support shaft 3 located above the rotary shaft 35.
6 are respectively supported. A driven side rotation link plate 37 is fixed to one side of the rotation shaft 35 so as to be able to rotate integrally with the rotation shaft 35. A tip end portion of the driven side rotation link plate 37 is fixed to the driven side rotation link plate 37. , The auxiliary balance 39, which extends upward and has the threading hole 38 formed at the upper end, is used as the driven side rotation link plate 3
It is rotatably connected to 7. Further, a tip end portion of a swing link plate 40 which is rotatably supported by a support shaft 36 is rotatably connected to a midway portion of the auxiliary balance 39. The moving link plate 37 and the swing link plate 40 form a predetermined link mechanism.

Further, an eccentric cam 41 is attached to a middle portion of the upper shaft 12 arranged inside the main body case 1, and a crank rod extending downward is provided on the outer peripheral side of the eccentric cam 41. 42 are connected. One end of a connecting rod 43 is rotatably connected to the lower end of the crank rod 42, and the connecting rod 43 is rotated by a rotating pin 44 provided in the main body case 1. It is supported swingably up and down about. This connecting rod 43
A driving side turning link plate 46 is rotatably connected to the tip end of the turning link plate 45 via a connecting link plate 45. The driving side turning link plate 46 is connected to the other end side of the turning shaft 35. It is rotatably supported integrally with the rotating shaft 35, and each of these members constitutes a transmitting means.

Also in this embodiment, similarly to the above-described embodiments, the rotation of the upper shaft 12 causes the unillustrated balance to swing up and down, and the unillustrated needle bar reciprocates up and down to perform a desired sewing operation. I am supposed to do it.

Further, in this embodiment, the transmission means, that is, the eccentric cam 41 is rotationally driven by the rotation of the upper shaft 12, and the eccentric cam 41 causes the connecting rod 43 to center around the rotating pin 44 via the crank rod 42. It is rocked up and down. As a result, the drive-side turning link plate 46 is swung up and down via the connecting link plate 45, and the turning shaft 35 is also turned accordingly. The rotation of the rotation shaft 35 causes the driven-side rotation link plate 37 to swing up and down, the auxiliary balance 39 to reciprocate up and down, and the upper thread 7 passing through the thread passing hole 38 of the auxiliary balance 39 The thread path can be changed.

As a result, the operation of the auxiliary balance 39 causes the path of the upper thread 7 to change in accordance with the vertical movement of the thread balance 2, so that the thread take-up curve of the thread balance 2 can be changed. By arbitrarily adjusting the length and stroke of the auxiliary balance 39, the yarn path by the auxiliary balance 39 can be arbitrarily changed,
The thread take-up curve of the balance 2 can be arbitrarily changed.

Therefore, also in the present embodiment, as in the above-mentioned respective embodiments, the thread take-up curve of the thread take-up 2 can be arbitrarily changed by swinging the auxiliary thread balance 39 to change the needle thread path. Therefore, the feeding amount of the upper thread 7 can be arbitrarily set, and the optimum upper thread 7 by the balance 2 can be set.
Can be fed out and an appropriate sewing operation can be performed.

The present invention is not limited to the above-mentioned embodiment, but can be modified in various ways as necessary.

[0033]

As described above, in the balance device of the sewing machine according to the present invention, the thread guide or the auxiliary balance is operated to change the thread path of the upper thread in synchronization with the swing motion of the thread balance. Since it is possible to locally change the thread take-up curve by, it is possible to make an arbitrary setting such as increasing when the amount of unrolled thread is insufficient or decreasing when the thread is over-supplied. The effect that the optimum thread can be paid out and the proper sewing operation can be performed is achieved.

[Brief description of drawings]

FIG. 1 is a schematic front view showing an embodiment of a balance device for a sewing machine according to the present invention.

2 is a schematic side view of FIG.

FIG. 3 is a plan view of the thread guide portion of FIG.

FIG. 4 is an explanatory diagram showing a change in a thread take-up curve of the balance according to the present invention.

FIG. 5 is a schematic front view showing another embodiment of the present invention.

6 is a schematic side view of FIG.

FIG. 7 is a perspective view showing a conventional general sewing machine.

FIG. 8 is an explanatory diagram showing a thread take-up curve by a conventional balance device.

[Explanation of symbols]

 1 main body case 2 balance 3 needle bar 7 upper thread 8 first thread tensioner 9 second thread tensioner 10 thread guide 12 upper shaft 14 counterweight 15 cam hole 19 balance crank 21 cylindrical cam 22 cam groove 23 mounting base 25 rocking Moving plate 29 Slide plate 35 Rotating shaft 36 Support shaft 39 Auxiliary balance 41 Eccentric cam 42 Crank rod 43 Connecting rod

Claims (2)

[Claims] 1. An upper shaft for vertically reciprocating a needle bar having a lower end attached with a needle is rotatably housed inside a main body case of a sewing machine, and a thread path is provided on a front side of the main body case. A balance through which the upper thread of the middle part is inserted is arranged so as to be swingable up and down, and the upper shaft and the balance are connected via a transmission mechanism, and the balance is vertically moved by rotationally driving the upper shaft. In a balance device of a sewing machine which is operated to perform the feeding operation of the upper thread, it is located in the middle part of the thread path on the front surface of the main body case, and the rotational movement of the upper shaft is transmitted by a transmission means. A thread balance device for a sewing machine, characterized in that a thread guide operative to change the thread path is arranged. 2. An upper shaft for vertically reciprocating a needle bar having a needle attached to a lower end thereof is rotatably housed inside a main body case of a sewing machine, and a thread path is provided on a front side of the main body case. A balance through which the upper thread of the middle part is inserted is arranged so as to be swingable up and down, and the upper shaft and the balance are connected via a transmission mechanism, and the balance is vertically moved by rotationally driving the upper shaft. In a balance device of a sewing machine which is operated to perform the feeding operation of the upper thread, it is located in the middle part of the thread path on the front surface of the main body case, and the rotational movement of the upper shaft is transmitted by a transmission means. A balance device for a sewing machine, characterized in that an auxiliary balance, which is vertically swingable so that the yarn path is changed, is provided.