JP2002191883A - Thread take-up lever mechanism in sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thread take-up lever mechanism for sewing machine, which is suitable for holding a thread take-up lever at a thread tension side position and threading from an upper part via a needle thread cassette, etc. SOLUTION: The mechanism is constituted by providing a thread guide member 106A for forming a thread guide gap 108 along the whole length of a movement locus in the threading part of the thread take-up lever, freely rotatably supporting the upper end part of the thread guide member 106A, putting the thread guide member 106A through an U shape guide part 25a in the tip part of the thread take-up lever 25 so as to be freely and relatively slidable, introducing a needle thread 24 from a thread introduction port 108a which is arranged at the upper end of the thread guide gap 108 and performing threading at a threading part 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance mechanism for a sewing machine, and more particularly, to a mechanism configured to allow easy threading from above.

[0002]

2. Description of the Related Art Conventionally, a balance mechanism of a sewing machine has a balance crank provided on a main shaft, a link-type balance drive mechanism or a cam-type balance drive mechanism connected to the balance crank, and a balance. A thread hook portion for hooking the upper thread is formed at the distal end portion. In a conventional balance, a folded piece that is folded back by a predetermined length is provided on an upper end portion of a curved balance main body, and a thread hook portion is formed at the tip of the folded piece. A thread introduction gap for introducing the upper thread is formed between the folded piece and the balance main body, and the upper thread is introduced from the thread introduction gap to be hooked on the thread hook portion.

[0003] On the other hand, in order to be able to quickly thread a thread on a thread catcher of a balance and a thread tensioner (including a pair of thread tension discs and a thread take-up spring), a thread spool is attached to a cassette mounting portion of an arm of a sewing machine. A technique has been proposed in which an upper thread cassette accommodating the upper thread is detachably mounted, and a thread is hooked when the upper thread is replaced in conjunction with the mounting of the upper thread cassette.

For example, US Pat. No. 3,749,039 discloses a sewing machine in which an upper thread cassette is configured to be detachable from an arm portion so that thread can be easily hooked.
A cassette mounting portion is provided substantially at the center of the arm portion of the sewing machine in the left-right direction, and the upper thread cassette is detachably mounted on the cassette mounting portion from above. The cassette mounting portion is formed on the right side of the balance moving space in which the balance of the balance mechanism reciprocates up and down, and the front end portion of the balance protrudes into the left end portion of the cassette mounting portion and reciprocates up and down.

The upper thread cassette has a cassette case having a substantially trapezoidal shape when viewed from the front. This cassette case comprises a case body and an opening / closing lid. A thread spool is accommodated in the upper thread spool accommodating portion in the cassette case with its axis being horizontal, and the upper thread of this thread spool is fed out to the right by a predetermined length substantially horizontally.
A first notch for inserting a thread tensioner is formed at a lower portion of a center portion of the cassette case, and a second notch for introducing a balance is formed at a lower portion of a left end of the cassette case. I have.

There are provided five thread guides for guiding the upper thread unwound from the thread spool. The first thread guide is provided above the right end of the cassette, the second and third thread guides are provided at positions sandwiching the first notch, and the fourth and fifth thread guides sandwich the second notch. Position. The first yarn guide is provided with a first resistance applying portion that applies resistance to the upper yarn in a state where the upper yarn cassette is not mounted on the cassette mounting portion and that opens after the cassette is mounted. The fifth yarn guide is provided with a second resistance applying portion that applies resistance to the upper thread when the cassette is not mounted and that opens after the cassette is mounted. This second
The resistance applying section applies a stronger resistance than the first resistance applying section.

At the left end of the cassette mounting portion provided on the arm portion, a thread guide member for guiding the upper thread when the upper thread cassette is mounted and guiding the thread to the thread hooking section of the balance is provided.
The thread guide member is formed by integrally forming a pair of left and right arm plates and a web. A guide surface for guiding the upper thread is formed at a rear end of the pair of arm plates. Notches (notches) corresponding to the hanging portions are formed.
Further, the upper thread cassette and the cassette mounting section are caused to open a pair of thread tension plates of the thread tensioner when the upper thread cassette is mounted,
A mechanism for closing the thread tension tray after the upper thread cassette is mounted is also provided.

When the upper thread cassette is mounted on the cassette mounting portion, first, the main shaft is rotated by manual operation to move the balance to the lowermost position. Next, when the upper thread cassette is mounted on the cassette mounting portion from above, the upper thread descends while being guided by the thread guide member, and the upper thread between the second and third thread guides is moved by the thread tensioner and the thread tensioner. The thread is automatically hooked on the tension spring, and the fourth, fifth,
The upper thread between the thread guides is guided by the guide surface of the thread guide member and is automatically threaded on the thread hooking section of the balance. When the upper thread cassette is in the installation completed state, the first and second resistance applying sections are turned on. The sewing machine is released, and during the subsequent sewing, the upper thread is fed from the thread spool.

On the other hand, Japanese Patent Laying-Open No. 55-81693 proposes a cassette type thread passing device for a sewing machine. In this cassette type threading device, a cassette mounting section provided in a balance moving area of the arm section and a right side area thereof, and a cover body for opening and closing the cassette mounting section are provided, and the upper thread cassette is attached to and detached from the cover body. A thread tensioner and a thread take-up spring protrude from the cassette mounting section, and there is a balance moving space at the left end of the cassette mounting section.

[0010] The upper thread cassette has a bobbin housing section, a pair of legs, and the like, and stores the upper thread unwound from the center of the bobbin.
Extend between the legs to form a free span. The cover body is turned forward by 90 degrees and opened, the upper thread cassette is set on the cover body, and then the cover body is closed. During the closing operation of closing the cover with the balance at the lowermost position, the free span of the upper thread cassette is automatically hooked to the thread tensioner and the thread take-up spring. Thereafter, when the balance is raised, the upper thread is automatically hooked on the thread hooking portion of the balance. When the cover is closed, the axis of the bobbin is oriented horizontally and in the front-rear direction.

[0011]

In the sewing machines described in the above publications, a thread having a normal structure is applied, and the upper thread cassette is attached to the thread while the balance is positioned at the lowest position by manual operation. Hang the thread on the balance and the balance. In this case, the operation of manually positioning the balance before mounting the upper thread cassette is cumbersome, and the work efficiency of the upper thread replacement is reduced.

In the conventional balance mechanism of a sewing machine, the upper thread cassette is mounted in a state where the balance is located at the thread tightening side position (the upper half side position in the reciprocating movement range) and interlocked with the mounting operation. It is almost difficult to thread. That is, since the balance having the above-described structure is employed, in a state where the balance is located at the thread tightening side position, the thread inlet of the thread introduction gap of the balance is located substantially behind the thread hooking portion of the balance. . However, since the thread tensioner is located near the front of the arm, the free thread portion of the upper thread linearly extended in the upper thread cassette should be applied to the thread tensioner and the balance almost simultaneously with the upper thread. Is difficult.

Although it is not impossible to simultaneously thread the thread tensioner and the balance by appropriately bending the thread path in the upper thread cassette, it is not impossible in this case. The structure of the inner yarn path and the upper yarn cassette becomes complicated, and the resistance of the upper yarn to pass increases, which is not preferable. SUMMARY OF THE INVENTION An object of the present invention is to provide a sewing machine balance mechanism suitable for holding a balance at a position on the thread tightening side and hooking a thread from above through a needle thread cassette or the like.

[0014]

According to a first aspect of the present invention, there is provided a balance mechanism for a sewing machine, comprising a balance for picking up an upper thread in synchronization with a sewing operation of the sewing machine. A thread guide member for forming a thread hooking portion and forming a thread guide gap extending in a curved shape along the entire length of the movement locus of the thread hooking portion of the balance; It is characterized in that the yarn can be introduced. The upper thread hung on the thread hook of the balance is located in the thread guide gap, and is guided by the thread guide member so as not to come off from the thread hook of the balance.

By introducing the upper thread from the direction of the movement locus of the balance into the thread guide gap while holding the balance at the position on the thread tightening side, the upper thread can be easily hooked on the thread hooking portion of the balance. The upper end of the thread guide gap is located at substantially the same position as the upper end of the movement locus of the thread hooking portion of the balance, and is located at a position where it does not largely retreat from the frontmost portion of the movement locus of the thread hooking portion. for that reason,
With the balance held at the position on the thread tightening side, the upper thread can be hooked on the thread hooking section of the balance in conjunction with the mounting operation of the upper thread cassette or the like.

A balance mechanism for a sewing machine according to a second aspect of the present invention is a balance mechanism having a balance for picking up an upper thread in synchronization with a sewing operation of the sewing machine. And a pair of thread guides extending in a curved shape along the entire length of the movement trajectory of the leading end of the balance and spaced apart back and forth with a thread guide gap provided, and a pair of thread guides in the U-shaped guide portion. The yarn guide is inserted so as to be relatively slidable. When the upper thread is introduced into the thread guide gap formed by the pair of thread guides from the direction of the movement locus of the balance and hangs on the U-shaped guide portion, the upper thread is located in the thread guide gap, and the U-shaped guide is provided. You will be guided so as not to get out of the department.

In the same manner as in the first aspect, the upper thread is easily introduced into the U-shaped guide portion by introducing the upper thread into the thread guide gap from the direction of the movement locus of the balance while holding the balance at the position on the thread tightening side. Can be multiplied. The upper end of the yarn guide gap is located at substantially the same position as the upper end of the movement trajectory of the U-shaped guide portion, and is located at a position where it does not largely retreat from the frontmost portion of the movement trajectory of the U-shaped guide portion. Therefore, while the balance is held at the position on the thread tightening side, the upper thread is moved in conjunction with the mounting operation of the upper thread cassette or the like.
It is also possible to thread on the shape guide.

According to a third aspect of the present invention, there is provided a balance mechanism for a sewing machine.
In the invention of the above, a thread catching portion for catching the upper thread from above is formed at a portion corresponding to between the pair of thread guides of the U-shaped guide, and the upper thread can be introduced into the thread guide gap from above. It is characterized by having comprised in. By introducing the upper thread into the thread guide gap from above, the thread can be hooked on the thread hooking section of the U-shaped guide section. The upper thread is held by the thread hooking section, and the thread is threaded by a pair of thread guides. You will be guided so as not to come off the hook.

According to a fourth aspect of the present invention, there is provided a balance mechanism for a sewing machine.
In the invention according to the third aspect, the pair of thread guides is formed of a single linear member having one continuous end, and the other end of the rear thread guide is rotatable with respect to the sewing machine frame. The U-shaped guide portion guides a pair of thread guides.

Since the pair of thread guides is constituted by one linear member, the number of members is reduced, and for example, the pair of thread guides can be constituted by a material which can be easily processed such as wire, and the structure is simplified. Also, since one end of the pair of thread guides is continuous,
A yarn introduction section for introducing the upper thread can be formed at the upper end of the yarn guide gap. The other end portion of the rear thread guide is rotatably mounted on the sewing machine frame, and the pair of thread guides is guided by the U-shaped guide. The sliding resistance of the thread guide is reduced, and the sliding noise is hardly generated.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. This electronically controlled sewing machine is configured such that an upper thread cassette accommodating a thread spool can be mounted on a cassette device section of an arm head, and in conjunction with the mounting operation when the upper thread cassette 2 is mounted, the thread of the balance is adjusted. The thread is hooked on the hook and the thread tensioner, and the thread is passed through the needle hole of the needle.

First, the basic structure of the sewing machine 1 and the threading mechanism 10 will be described in order. Then, the upper thread cassette 2, the cassette mounting section 3, the balance mechanism 8, and the transmission mechanism 115 for threading will be described.
The interlocking mechanism 134 for the thread tensioner 9 will be described in this order.
In the following description, front, rear, left, and right as viewed from a person operating the sewing machine will be described as front, rear, left, and right.

As shown in FIGS. 1 to 3, the electronically controlled sewing machine 1 includes a bed 4, a pillar 5 erected on the right end of the bed 4, and a top end of the pillar 5. It has an arm 6 extending leftward. The arm section 6 is provided with a needle bar vertical movement mechanism 7, a cassette mounting section 3, a balance mechanism 8, a thread tensioner 9, and an automatic threading mechanism 10. The cassette mounting section 3 is provided on the head of the arm section 6 (arm head). A main shaft 11 is rotatably supported in the arm portion 6 via a pair of bearings 12, and the main shaft 11 is rotated by a driving force of a sewing machine motor (not shown).

Next, the needle bar vertical movement mechanism 7 will be described. Since this mechanism has a general structure, it will be briefly described. As shown in FIGS. 1 and 3 to 8, a needle bar base frame 13 is disposed on the arm head of the arm portion 6 in an upright position, and the needle bar base frame 13 includes a rear wall portion 14 and a left wall portion. A lower support portion 14a and an upper support portion 14b extending forward are integrally formed at the lower end and the upper end of the rear wall portion 14, respectively.
A pivot arm 15a extending above the upper support 14b is formed at the upper end of the left wall 15, and the needle bar 18 passes through the upper support 14b and the lower support 14a so as to be vertically movable. .

A shaft member 16a facing in the left-right direction is fixed to the upper end of the pivot arm 15a, and a pivot bracket 16 having a front open shape and a substantially U-shape in plan view is fixedly connected to the shaft member 16a. The pivot bracket 16 is swingably supported by the sewing machine frame via a horizontal support shaft 17 oriented in the front-rear direction, and the needle bar base frame 13 is moved left and right (needle swing direction) around the support shaft 17 as the swing center. Swingable to Note that a mechanism for swinging and driving the needles via the needle bar base frame 13 by the stepping motor is a general mechanism, and thus the description thereof is omitted. Needle bar 18
Is supported by the upper support portion 14b and the lower support portion 14a so as to be vertically movable, and a needle 19 is detachably attached to a lower end of the needle bar 18.

As shown in FIGS. 3 and 11 to 13, the balance crank 20 of the balance mechanism 8 is provided at the left end of the main shaft 11.
Is provided, and a crank pin 21 is attached to the balance crank 20.
The needle bar crank 22 is rotatably connected via the. A needle bar holder 23 is fixed to a substantially middle portion of the needle bar 18,
A needle bar crank 22 is connected to a needle bar holder 23. At the time of sewing, the main shaft 11 is rotationally driven by the sewing machine motor,
The needle bar 18 is reciprocated up and down by the needle bar crank 22.

As shown in FIGS. 11 to 15 and 17, the arm section 6 is provided with a balance mechanism 8 having a balance 25 for picking up the upper thread 24 in synchronization with the vertical movement of the needle 19. . A thread hook 26 is formed at the tip of the balance 25 so that the thread can be hooked from above. The thread hook 26 of the balance 25 can reciprocate up and down over the entire height of the right end portion of the cassette mounting section 3. A moving area 27 is provided. A thread tensioner 9 for providing a passing resistance to the upper thread is provided so as to protrude below the cassette mounting section 3.

The thread tensioner 9 can be opened and closed by a presser lifting lever 29 for raising and lowering the presser foot 28. As will be described later, even when the upper thread cassette 2 is mounted, the thread tensioner 9 can be operated.
Is opened and closed. A substantially vertical vertical axis is provided in the pillar portion 5, and the vertical axis is connected to the main shaft 11 via a gear mechanism.
The driving force on the vertical axis is transmitted to the yarn catching hook in the bed section 4. Similar to a general electronic control sewing machine, the work cloth 30 is sewn by cooperation of the needle 19, the thread catching hook, and the cloth feeding mechanism driven by the stepping motor.

Next, an automatic threading mechanism 10 for threading the upper thread 24 into the needle hole 19a of the needle 19 will be described with reference to FIGS.
This will be described with reference to FIGS. 14, 15, 17, and 19.
Upper support portion 14b and lower support portion 14a of needle bar base frame 13
A threading shaft 31 and a slider guide shaft 32 located on the left side of the needle bar 18 are supported so as to be vertically movable. The upper end of the threading shaft 31 is connected to the bracket 16 and the shaft member 16a.
A sliding pin 33 projecting in the horizontal direction is fixed to a substantially middle portion of the threading shaft 31.

A hook holding member 34 made of synthetic resin is fixed to the lower end of the threading shaft 31. The threading shafts 31 corresponding to the upper and lower sides of the hook holding member 34 have a substantially U-shaped side view. The upper and lower support portions of the first thread guide member 35 (see FIG. 17) are rotatably supported. Of the first thread guide member 35, a thread guide 36 a that engages and guides the upper thread 24 is formed in a notch on a vertical connecting wall 36 that connects the upper support section and the lower support section. ing.

As shown in FIGS. 9A to 9C, a hook mechanism 37 is fixed to the hook holding member 34. The hook mechanism 37 includes a threading hook 37a and a threading hook 3a.
It comprises two guide members 37b located on both sides of 7a, a thread holding wire 37c that horizontally passes through the threading hook 37a and the guide member 37b, and the like. A hook portion is formed at the tip of the threading hook 37a. The hook portion is inserted into the needle hole 19a during threading, and the needle 19 is positioned immediately before the needle hole 19a while being guided by the guide member 37b. The thread 24 is hooked.

A second thread guide member 38 is integrally fixed to the hook holding member 34, and a portion near the distal end of the second thread guide member 38 is bent downward, and the bent portion is formed into a thread guide portion 38a. Functioning as The thread guide portion 38a is located on a side substantially opposite to the hook mechanism 37 with respect to the threading shaft 31, and is separated by a predetermined distance. That is, the second thread guide member 38 and the hook mechanism 37 are provided integrally with the threading shaft 31 while maintaining a fixed positional relationship.

Next, a rotating mechanism for rotating the threading shaft 31 by a predetermined angle will be described. 5 to 8, 14,
As shown in FIG. 15, FIG. 17, and FIG. 19, a threading slider 40 made of synthetic resin is provided on the upper end of the threading shaft 31 and the slider guide shaft 32 on the back side of the needle bar base frame 13.
Are externally fitted to be vertically movable. That is, the threading slider 40 includes the upper pivot 41 and the lower pivot 42 and the outer peripheral wall 4.
3 and a threading slider claw 44.

The upper pivot portion 41 and the lower pivot portion 42 are provided over the threading shaft 31 and the slider guide shaft 32, and the outer peripheral wall 43 is formed by the upper pivot portion 41 and the lower pivot portion 4.
2 is formed vertically so as to cover substantially half of the outer periphery of the upper end of the threading shaft 31. A spiral threading slider cam portion 43a is formed on the outer peripheral wall portion 43. A threading slider claw 44 is connected to the left end portions of the upper pivot portion 41 and the lower pivot portion 42, and a claw portion 44a is formed at a substantially middle portion of the left end.

A sliding pin 33 having a predetermined length is fixed at a position corresponding to a position directly above the lower pivot 42 in a substantially middle portion of the threading shaft 31. The side end is engaged with the threading slider cam portion 43a. On the lower side of the threading shaft 31 by a certain length from the sliding pin 33,
A spring receiving pin 45 is fixed in a penetrating manner, and a compression coil spring 46 is provided between the lower pivot 42 and the spring receiving pin 45 of the threading shaft 31. A compression coil spring 47 for urging the threading slider 40 upward is provided between the lower pivot portion 42 of the slider guide shaft 32 and the lower support portion 14a of the needle bar base frame 13.

The offset member 48 will now be described. As shown in FIGS. 4 to 8, the threading shaft 31 and the slider guide shaft 32 are provided on the back side of the threading slider 40 and in the needle bar base frame 13. An offset member 48 is vertically movably mounted in a range of about ／ of the height between the upper support portion 14b and the lower support portion 14a. The offset member 48 includes an upper support 49, a lower support 50, and a vertical connecting wall 51 connecting the upper support 49 and the lower support 50. The upper support 49 is inserted through the threading shaft 31 and the slider guide shaft 32, and the lower support 50 is inserted through only the threading shaft 31.

Immediately above the needle bar holder 23 of the needle bar 18,
The threading positioning member 52 as an engagement piece is fixed, and the right end portion of the upper support portion 49 of the offset member 48 is configured to be able to contact the threading positioning member 52 from above. With the right end portion of the upper support portion 49 in contact with the threading positioning member 52, the threading hook matches the height position of the needle hole 19a of the needle 19 (see FIG. 6). An offset member cam portion 53 is formed at a lower left portion of the connecting wall 51, and the offset member cam portion 53
An inclined portion 53a protruding leftward toward the lower side, and a flat portion 53b extending vertically downward from the lower end of the inclined portion 53a, and a flat portion projecting slightly leftward from the claw portion 44a of the threading slider claw 44. 53b.

The upper thread cassette 2 described later moves the threading slider 40 against the urging force of the compression coil spring 47 as shown in FIG.
When the threading shaft 31, the slider guide shaft 32, and the offset member 48 follow and descend, the upper support portion 49 of the offset member 48 abuts on the threading positioning member 52. (See FIG. 6). At this time, the threading shaft 31 and the slider guide shaft 3
Since the threading slider 40 is relatively lowered with respect to 2, the sliding pin 33 becomes a spiral threading slider cam portion 43.
Move along a. The threading shaft 31 is rotated clockwise in a plan view by a predetermined angle and threaded (FIG. 9).
(See (a) to (c)).

At the time of this threading, the hook mechanism 37 is connected to the needle 1
9, the threading hook is inserted through the needle hole 19a. At the same time, the second thread guide member 38 is rotated clockwise (in a direction away from the needle 19) in synchronization with the hook mechanism 37. When threading, the threading shaft 31
A link mechanism 54 for rotating the first thread guide member 35 rotatably supported at the lower end of the first thread guide member 35 in a direction away from the second thread guide member 38 is also provided. That is, when the threading shaft 31 is in a standby state before rotating for threading, the second thread guide member 35 is in a forward-facing posture, and the second thread guide member 3
The thread guide portion 38a of No. 8 is located immediately inside the thread guide 36a of the connecting wall 36.

When the threading shaft 31 rotates after descending to the lower limit position, the hook mechanism 37 and the second thread guide member 3 are rotated.
8 integrally rotates clockwise in plan view, and the first thread guide member 35 rotates counterclockwise via the link mechanism 54. That is, the first yarn guide member 35
Move away from the second thread guide member 38 and move closer to the hook mechanism 37. In the vicinity of the link mechanism 54, a support plate 55 for holding the upper thread 24 with a small pressure is provided.
A yarn guide tray 56 is also provided.

Next, the upper thread cassette 2 will be described.
As shown in FIGS. 1, 10, and 14 to 36, the upper thread cassette 2 includes a cassette case 57 having a shape close to a vertically long rectangular parallelepiped with a small width in the left-right direction, and a thread piece storage portion 57 a for storing the thread piece 62. A thread spool holding portion 58 for holding the thread spool 62 in the thread spool receiving portion 57a; and a thread spool 6 held by the thread spool holding portion 58.
2 and the upper thread 24 unwound from the thread spool 62
A thread path 59 for guiding the thread tension, a balance moving area 57b in which the thread hooking part 26 of the balance 25 of the balance mechanism 8 reciprocates up and down, and a thread tensioner accommodation unit 5 into which the thread tensioner 9 is inserted.
7c and the like. A thread outlet 68 is formed near the right end of the bottom wall of the cassette case 57.

The cassette case 57 has a cassette body 60 made of synthetic resin and an opening / closing lid 61.
An opening / closing lid 61 is connected to the right end portion so as to be openable and closable. However, the opening / closing lid 61 may be configured to slide up and down with respect to the cassette body 60 to open and close. As a thread color identifying means for identifying the thread color of the upper thread 24 of the thread spool 62, the opening / closing lid 61 is made of a transparent material so that the thread color of the thread spool 62 in the cassette case 57 can be identified. As another thread color identification means, for example, an opening hole for viewing the thread spool 62 may be formed in the opening / closing lid 61, or the upper thread of the thread spool 62 may be formed in a part of the surface of the cassette case 57. A seal of the same color as the color 24 may be attached.

As shown in FIGS. 10, 16, and 28-33, the balance moving area 57b is formed in the right side of the cassette case 57 at about 1/3 width, and the thread spool accommodating section 57a is formed in the cassette case 57. The thread tensioner accommodating portion 57c is formed in the upper approximately 2/3 of the approximately 2/3 width portion on the left side, and the lower portion of the approximately 2/3 width portion on the left side in the cassette case 57. An area for the yarn path 59 is partitioned by partition walls 66 and 99 at the left end in the cassette body 60.

In the balance moving area 57b, a vertically elongated slit 101 is formed in the rear wall of the cassette body 60 for allowing the thread hook 26 of the balance 25 and a thread guide member 106A described later to protrude. A notch 96 for introducing the thread tensioner 9 into the thread tension device accommodating portion 57c is formed in the rear wall and the bottom wall of the cassette main body 60 in the thread tension device accommodating portion 57c.
Vertical partition walls 67 and 100 are formed between the balance moving area 57b and the thread spool accommodating section 57a and the thread tensioner accommodating section 57c, and an opening / closing lid is provided between the thread spool accommodating section 57c and the thread tension instrument accommodating section 57a. A horizontal support wall 63 protruding toward the side 61 is formed.

Since the thread spool holding portion 58 is configured to hold the thread spool 62 in the vertical direction, the width of the cassette case 57 in the left-right direction is reduced, and the cassette case 57 and the cassette mounting portion are reduced. 3 can be reduced in size. The spool holder 58 includes a support wall 63 (corresponding to the wall of the storage unit) and a spool holder shaft 64. A thread spool holding shaft 64 is provided on the support wall 63 so as to protrude upward. The thread spool holding shaft 64 is formed in three in the circumferential direction, is elastically deformable in the radially expanding direction, and can hold the thread spool 62 having shaft holes of various sizes.

A recess for pushing the thread spool 62 from below and removing it upward from the thread spool holding shaft 64 is provided at the front end of the portion of the support wall 63 which contacts the lower end (one end in the axial direction) of the thread spool 62. 65 are formed. The concave portion 65 is
The upper thread 24 is formed in a notch shape depressed radially inward from the outer peripheral surface of the upper thread 24 so that the upper thread 24 does not enter between the thread spool 62 and the support wall 63 even if the upper thread 24 is loosened.

Next, the yarn path 59 will be described. FIG.
4, FIG. 15, FIG. 17 to FIG.
Is an upper thread guide path that guides the upper thread 24 that has been unreeled upward from the thread spool 62 to the thread outlet 68 of the cassette case 57, using the unwinding point 79 from the thread spool 62 held by the thread spool holding portion 58 as a base point. The yarn path 59 has a first guide section 69, a first holding section 70, a second guide section 71, a third guide section 72, and a second holding section 73. In a state where the thread spool 62 is held by the thread spool holding portion 58, the upper thread 24 that has been unreeled upward from the thread spool 62 is provided with a first guide portion 69, a first holding portion 70, a second guide portion 71, and a third guide portion. The cassette case 57 is guided to the yarn outlet 68 at the lower end portion near the right end of the cassette case 57 via the portion 72 and the second holding portion 73 in order.

As shown in FIGS. 17, 19, and 22 to 25, the first guide portion 69 and the first holding portion 70
Is provided on the upstream side of. The first guide section 69 is provided on the top of the cassette case 57. The first guide portion 69 is provided with a pin support member 7 formed on the cassette body 60.
4, an L-shaped guide pin 75 projecting forward from the pin support member 74 and bent rightward, and an open / close lid 61
And a rib 76 for preventing the thread from coming off.

The guide pin 75 has a thread guide portion having a predetermined length in the front-rear direction. The top wall of the cassette body 60 and the opening / closing lid 61 is rectangularly cut so that the thread guide portion faces the outside. Notched openings 77 and 78 are formed to face each other,
An upper thread supplied from an external thread spool can be introduced into the first guide portion 69 from the openings 77 and 78. The upper thread 24 drawn out from the thread spool 62 is movably hung on the thread guide portion of the guide pin 75 in the front-rear direction, so that even when the distance between the thread spool 62 and the first guide portion 69 is not so long, The upper thread 24 can be smoothly pulled out from the thread spool 62.

The first holding portion 70 will be described with reference to FIG.
3. As shown in FIG. 24, the first holding portion 70
The first holding portion 70 is provided inside the cassette case 57 to provide a passing resistance to the upper thread 24 in the upstream portion of the upper thread 9 and to prevent the upper thread from being entangled with the upper thread. Near the upper end of the left end.
The first holding portion 70 includes a holding plate 80 having a thread guide portion 80a.
And a pressing prevention mechanism 82 formed of a thread provided with a leaf spring 81 for pressing the upper thread 24 on the pressing plate 80.

The holding plate 80 and the leaf spring 81 are connected to the cassette body 6.
0 is fixed to the partition wall 66. The thread guide portion 80a of the presser plate 80 is a narrow notch that is open upward, and the thread guide portion 80a protrudes forward from the cassette body 60.
The leaf spring 81 abuts on the left side surface of the thread guide 80a, sandwiches the upper thread 24 with the thread guide 80a, and imparts a passage resistance to the upper thread 24 so that the upper thread 24 is twisted by the thread. The occurrence of entanglement or the like is prevented.

Next, FIG. 14, FIG. 15, FIG.
As shown in FIGS. 26 and 27, the second and third guide portions 71,
The second holding portion 72 and the second holding portion 73 are provided on the downstream side of the yarn path 59. The second guide portion 71 is located at the lower end of the left end in the cassette case 57, and the third guide portion 72 is located at the lower end of the boundary between the thread tension device accommodating portion 57c and the balance moving area 57b in the cassette case 57. The second holding portion 73 is located near the lower end near the right end in the cassette case 57.

The upper thread 24 extends obliquely from the first guide portion 69 to the first holding portion 70, extends vertically from the first holding portion 70 to the second guide portion 71, and extends from the second guide portion 71 to the third guide portion. Part 7
2 and extend from the third guide portion 72 to the second holding portion 73 substantially horizontally or in an inclined manner. Thus, the upper thread 24 is guided so as to cross along the lower end of the cassette case 57.

The second guide 71 includes a pin support 83 provided on the rear wall of the cassette body 60, a guide pin 84 fixed to the pin support 83 and protruding forward, and an opening / closing lid 61.
And a rib 85 for preventing the thread from coming off. The pin support portion 83 and the rib 85 appropriately set the position of the upper thread 24 in the front-rear direction. The third guide portion 72 is provided in the cassette body 6.
0, a pin support portion 86 provided on the rear wall portion, a guide pin 87 fixed to the pin support portion 86 and protruding forward, a rib 88 formed on the opening / closing lid 61 for preventing thread coming off, and the like. The pin support portion 86 and the rib 88 appropriately set the position of the upper thread 24 in the front-rear direction.

Next, the second holding portion 73 will be described.
As shown in FIGS. 14, 15, 17 to 21, and 33 to 36, the second holding portion 73 provides the upper yarn 24 with a passage resistance near the yarn outlet 68. Regardless of whether the upper thread cassette 2 is not mounted on the cassette mounting section 3 or the state where the mounting is not completed, the second holding section 73 retains the upper thread 2.
4 is configured to give a stronger passage resistance than the first holding portion 70. Therefore, when the upper thread 24 is hooked to the thread hooking section 26 of the balance 25 and the thread tensioner 9 when the upper thread cassette 2 is mounted, the upper thread 24 is moved between the second guide section 71 and the second holding section 73. Is maintained in a tensioned state, so that the thread can be securely hooked on the thread hooking portion 26 of the balance 25 and the thread tensioner 9, and the upper thread 24 necessary for the thread hooking can be securely fed from the thread spool 62. Can be paid out.

The second holding portion 73 includes a movable shaft member 94 whose axis is oriented horizontally in the left-right direction, a guide pin 89 for guiding the upper thread 24, a thread holding plate 90, a leaf spring member 91 and the like. Have been. The movable shaft member 94 includes a small-diameter shaft portion, and a large-diameter operation button 94a that can be protruded and retracted from the right side surface of the lower end portion of the cassette body 60. This movable shaft member 94
Is mounted on the vertical wall portions 92 and 93 near the right end and the lower end of the cassette body 60 so as to be horizontally movable in the left-right direction, and is elastically biased rightward by the leaf spring member 91.

A guide pin 8 is provided at the left end of the movable shaft member 94.
9 is fixed to the rear end portion in the front-rear direction.
A thread holding plate 90 for holding the upper thread 24 is fixed between the guide pin 89 and the left side surface of the vertical wall 93, and the guide pin 89 urged rightward with the movable shaft member 94. By sandwiching the upper thread 24 between the upper thread 24 and the thread holding plate 90, the upper thread 24 is provided with passage resistance.

As shown in FIGS. 14 and 18, when the upper thread cassette 2 is removed from the cassette mounting portion 3, the operation button 94 is pressed by the urging force of the leaf spring member 91.
The leading end of “a” protrudes from the right side surface of the cassette body 60. Therefore, when the upper thread 24 is fed from the thread spool 62 in a state in which the upper thread cassette 2 is not mounted on the cassette mounting section 3, the operation shaft 94 and the guide pin 89 are pushed by pushing the operation button 94a with a finger. By moving it to the left to open the second holding portion 73, the upper thread 24 can be fed out against the passage resistance of the first holding portion 70. Then, as described later, in a state where the upper thread cassette 62 is completely mounted on the cassette mounting section 3, the second holding section 73 is in an open state so as not to give the upper thread 24 a passage resistance.

As shown in FIGS. 19 and 20, even when the upper thread cassette 2 is completely mounted on the cassette mounting portion 3, the second holding portion 73 is opened so that the second holding portion 73 is opened. Vertical groove 95 for releasing operation button 94a
a, and an upper thread release cam 95 for retracting the operation button 94a when the installation of the upper thread cassette 2 is completed. These will be described later in the description of the cassette mounting section 3.

When the upper thread cassette 2 is completely mounted on the cassette mounting section 3, the second holding section 73 is in an open state, but the thread tensioner 9 which enters the thread tensioner accommodating portion 57c in the upper thread cassette 57 is provided. The upper thread 24 is held between the first holding portion 70 and the thread tensioner 9, so that the upper thread 24 is kept in a tensioned state. Therefore, the upper thread 24 of the thread path 59 upstream of the thread tensioner 9 is not entangled with the thread by the thread. Instead of equipping the arm tensioner 9 with the thread tensioner 9, it is also possible to equip the upper thread cassette 2 with a thread tensioner 9, and in this case as well, the first clamping unit 70 and the thread Since the upper thread 24 between the tensioners 9 is maintained in a tensioned state, it is possible to prevent the thread from becoming entangled with the twisted thread.

As described above, the upper thread 24 is held in the first holding portion 70
When the upper thread is clamped between the thread tension discs 9 and the thread tension discs to be described later, and the upper thread is tensioned between them, the thread tension of the thread tension disc 9 at the entrance portion of the thread tension disc is adjusted. When the upper thread is pinched and resistance is added, in this part, the original structure of the thread is strengthened in the direction of tightening further,
In the upper thread portion between the first holding portion 70 and the thread tension plate of the thread tensioner 9, a thread that is stronger than the original structure of the thread is always generated.

In this state, if the upper thread portion is loosened during this time, the upper thread portion is bent at a certain point, and a phenomenon occurs in which the threads are tangled in a straight line or a dumpling shape around this portion. When such a entangled portion is guided to the thread tension plate of the thread tension device 9, the thread tension plate is caught on the thread tension plate, causing thread breakage or thread pulling. However, as described above, the upper thread 24 is connected to the first holding portion 70 and the thread tensioner 9.
The above-described entanglement phenomenon does not occur by sandwiching the upper thread portion between each of the thread tension plates and holding the upper thread portion in a tension state therebetween. The upper thread portion of the thread tensioner 9 that has passed through the thread tension plate returns the thread reinforced as described above.

Next, the upper thread cassette 2 is inserted into the cassette mounting section 3.
A description will be given of a configuration for causing the thread tensioner 9 to protrude into the thread tensioner accommodating portion 57c in the cassette case 57 when the thread tensioner 9 is mounted on the cassette case 57. 1, 14, 15, 23, 26, 3
0, as shown in FIG. 31, below the thread tensioner accommodating portion 57c, the bottom walls of the cassette body 60 and the opening / closing lid 61
Openings 97 and 98 in the form of rectangular cutouts are formed to face each other, and a cutout 96 having a partially oblong shape connected to the opening 97 is formed in the rear wall of the cassette body 60. When the upper thread cassette 2 is mounted, the notch 96 and the openings 97, 98
The thread tension device 9 is accommodated in the thread tension device accommodating portion 57c so as to protrude therethrough.

As shown in FIGS. 1, 3, 11 to 15, 26, 27, 30, and 31, the balance moving area 57
b, rectangular cutout-shaped openings 102 and 103 are formed in the bottom walls of the cassette body 60 and the opening / closing lid 61 so as to face each other, and the rear wall of the cassette body 60 is connected to the opening 102 and has a lower end. Vertical slit extending from the top to near the top
When the upper thread cassette 2 is mounted on the cassette mounting section 3, the thread hooking section 26 of the balance 25 and the thread guide member 106A protrude into the cassette case 57 through these openings 102 and 103 and the slit 101. Will be introduced.

As shown in FIGS. 21, 22, and 24, of the rear wall of the cassette body 60, the rear wall facing the thread spool accommodating portion 57a is partially cylindrical rearward for accommodating the thread spool 62. A portion corresponding to the lower end of the partial cylindrical portion is engaged with a receiving portion 109 described later of the cassette mounting portion 3 from above to determine the height position of the upper thread cassette 2. Part 11
2 is formed.

At the left and right ends of the rear wall of the cassette main body 60, protruding engaging portions 113 and 114 are formed which can be engaged with guide grooves 110 and 111 of the cassette mounting portion 3 described later, respectively.
With the upper thread cassette 2 mounted on the cassette mounting section 3,
The front surface of the opening / closing lid 61 is not flush with the front surface of the arm portion 6,
The upper walls of the cassette body 60 and the opening / closing lid 61 are formed so as to be flush with the upper surface of the arm 6 (FIGS. 19 and 2).
2).

Next, the thread stopper 104 of the upper thread cassette 2 will be described. As shown in FIG. 25, FIG. 30, FIG. 35 and FIG.
Between the chamfered portion 105 of the pivot portion 1 and the cassette body 60 which is in contact with the chamfered portion 105 with the opening / closing lid 61 closed, the yarn end side portion of the upper thread 24 extending to the outside of the upper thread cassette 2 is The thread fixing portion 104 is constituted by the chamfered portion 105 and a part of the cassette main body 60. However, as shown in FIGS. 35 and 36, a leaf spring piece urged toward the case is provided on the outer surface of the cassette case 57, and the thread end of the upper thread 24 is attached to the leaf spring piece as shown in FIGS. You may comprise so that a part may be temporarily fixed.

Next, the cassette mounting section 3 for removably mounting the upper thread cassette 2 from above will be described. As shown in FIGS. 1, 2, 4, and 21, the cassette mounting portion 3 is provided at the distal end portion (arm head) of the arm portion 6 of the sewing machine.
Are formed in a vertically elongated rectangular shape in a front view and in an elongated rectangular cross-sectional shape in a substantially right and left direction. At the right end side of the cassette mounting section 3, a vertically elongated balance moving area 27 in which the thread hooking section 26 of the balance 25 reciprocates is provided, and most of the cassette mounting section 3 excluding the balance moving area 27 moves the balance. It is located on the left side of the area 27.

With the axis of the thread spool 62 held by the thread spool holding portion 58 substantially parallel to the reciprocating direction of the thread hooking portion 26 of the balance 25, the upper thread cassette 2 can be mounted from above in the vertical direction.
The upper end and the lower end of the cassette mounting portion 3 are formed open so that the upper thread cassette 2 can be removed vertically upward. A thread tensioner 9 is provided near the lower end of the cassette mounting portion 3 slightly to the left of the center thereof so as to project forward with its axis centered in the front-rear direction.

The lower portion of the rear wall of the cassette mounting portion 3 receives the engaging portion 112 of the upper thread cassette 2 and
Step-shaped receiving portion 109 for positioning 7 at a predetermined height position
Are formed. Guide grooves 110 and 111 are formed near the rear ends of the left side wall and the right side wall of the cassette mounting portion 3 to guide the engaging portions 113 and 114 of the upper thread cassette 2 slidably, respectively.

Next, the upper thread release cam 95 provided in the cassette mounting section 3 for switching the second holding section 73 to the open state will be described. As shown in FIGS. 18 and 20, at the rear part of the right side wall of the cassette mounting part 3, the above-mentioned vertical groove part 95a and an upper thread releasing cam 95 located at the end side thereof are formed. The vertical groove 95a is continuous from the upper end to the vicinity of the lower end of the cassette mounting section 3, and the upper thread release cam 95 is
a through the tapered portion 95b to the lower end of the vertical groove 95a.
Projecting to the left.

Accordingly, as shown in FIGS. 17 and 18, the operation button 94 projecting from the right side of the cassette main body 60 is inserted into the groove 95a until the upper thread cassette 2 is mounted on the cassette mounting section 3 and immediately before the mounting is completed. Move along. At this time,
The second holding portion 73 imparts passage resistance to the upper thread 24. When the upper thread cassette 57 is completely mounted on the cassette mounting section 3 and the mounting of the upper thread cassette 57 is completed, the operation button 9
4 comes into contact with the upper thread release cam 95 and is pushed to the left. At this time, the second holding portion 73 is in the open state,
No passing resistance is given to the upper thread 24.

Next, the balance mechanism 8 will be described in detail. As shown in FIGS. 11 to 14, the balance mechanism 8
This is a unique structure that is designed so that the upper thread 24 can be hooked on the thread hooking section 26 in conjunction with the operation of mounting the upper thread cassette 2 on the cassette mounting section 3. The balance mechanism 8 is exemplified by a cam-type balance mechanism, but the following configuration can be similarly applied to a link-type balance mechanism.

The balance mechanism 8 includes a balance 25 driven by a driving force of a main shaft via a balance crank 20 and a balance 2
5 has a thread guide member 106A that forms a thread guide gap 108 that extends in a curved shape along the entire length of the movement locus of the thread hooking section 26. The upper thread 24 is introduced into the thread guide gap 108 from above and threaded. The portion 26 is configured to be threadable.

The thread guide member 106A extends in a curved shape along the entire length of the movement trajectory of the leading end (the thread hooking portion 26) of the balance 25, and a pair of thread guide members 10 spaced apart in the front and back with a thread guide gap 108 therebetween.
Consists of six. A pair of thread guides 106 are continuous at the lower end.
The upper end of the thread guide 106 on the rear side extends horizontally rearward and pivots on the top frame of the sewing machine frame via the pivot bracket 107. It is freely supported, and the lower end of the thread guide member 106A is a free end.
The upper end of the front yarn guide 106 is bent forward to introduce an upper thread 24 into the yarn guide gap 108 from above.
108a is formed. The thread guide member 106A and the balance 25
The thread hook 26 protrudes into the cassette mounting unit 3 from an opening in the rear wall of the cassette mounting unit 3.

The front end portion of the balance 25 has a U-shape formed by folding back a predetermined length on the front end side in a plan view.
A shaped guide 25a is provided. A pair of thread guides 10
6 passes through the U-shaped guide portion 25a so as to be relatively slidable.
When the U-shaped guide 25a reciprocates up and down, the pair of thread guides 106 rotate at the upper end while the U-shaped guide 2 is rotated.
Since the guide is guided by 5a, the sliding resistance to the U-shaped guide portion 25a is small, and almost no noise is generated. U-shaped guide part 25
In the portion corresponding to the space between the pair of yarn guides 106 (that is, the yarn guide gap 108), a U-shaped portion 26 for hanging the upper thread 24 from above, and a U-shape for hanging the upper thread on the upper surface. A thread hook 26 having a concave portion is formed.

Therefore, when the axis of the thread spool 62 is substantially parallel to the reciprocating direction of the thread hooking portion 26 of the balance 25, and the upper thread cassette 2 is mounted from above vertically, the upper thread cassette 2 is automatically interlocked with the mounting operation. In addition, the upper thread 24 between the third guide section 72 and the second holding section 73 of the upper thread cassette 57 can be introduced into the thread guide gap 108 from the introduction port 108a and easily hooked on the thread hook section 26 of the balance 25. it can. Note that the thread guide member 106A may be a metal or synthetic resin plate-like member instead of a linear member.

Next, the transmission mechanism 115 for transmitting the operation of the upper thread cassette 2 to the automatic threading mechanism 10 will be described. As shown in FIGS. 5 to 8, the transmission mechanism 115 transmits the operation of the upper thread cassette 2 to the automatic threading mechanism 10 via the threading slider operating mechanism 116 and engages with the threading positioning member 52. An engagement mechanism 117 is provided which can be released in some cases. The threading slider operating mechanism 116 includes a threading slider operating member shaft 118 (hereinafter referred to as a shaft 118),
A threading slider operating member 119, a threading slider operating member lever 120 (hereinafter, referred to as a lever 120), a threading slider operating claw 121 (hereinafter, referred to as an operating claw 121), and a threading slider operating claw spring 122 (screw) Spring 122) and a threading slider operating member stopper 123 (hereinafter referred to as a stopper).
123).

As shown in FIGS. 4, 5, and 10, a shaft 118 is vertically supported in the arm 6 near the cassette mounting portion 3, and has a substantially U-shape in side view. A threading slider operating member 119 is supported so as to be vertically movable. A lever 120 having a U-shape in a plan view is fixed to the threading slider operating member 119, and a plate-like lever portion 120a is provided at a substantially middle portion at the right end of the front plate portion of the lever 120 so as to protrude forward. Have been. The tip of the lever 120a is
It is formed so as to protrude from the inside of the arm portion 6 by a predetermined length through the receiving portion 109 of the cassette mounting portion 3. A slit 124 is formed from a substantially middle portion to a lower end of the receiving portion 109, and the lever portion 120a is configured to be vertically movable along the slit 124.

The top plate near the upper end of the shaft 118 has a bracket 12
5 is fixed, and a tension coil spring 126 is interposed on the back side of the shaft 118 and between the stopper 123 and the lever 120.
The lever 120 (that is, the lever portion 120a) is urged upward. Incidentally, in order to hold the completed state (sewing position) of the upper thread cassette 2, the frictional resistance acting between the thread holding button 94 and the cam 95 is made larger than the urging force of the tension coil spring 126.

The engagement mechanism 117 will be described with reference to FIGS.
As shown in FIG. 8, an operating claw 121 is pivotally supported on the upper right end of the lever 120. The operating claw 121 is configured to be swingable between a lock position where the lower end thereof can be engaged with the claw portion 44a of the threading slider claw 44 and a release position where the engagement state with the claw portion 44a is released. ing. However, the threading slider operating member 119, the operating pawl 12
The torsion spring 122 acting between the two is externally provided, and the
To the lock position side.

The lower end of the operating claw 121 is configured to be able to contact and separate from the offset member cam portion 53. When the threading slider operating member 119 is pushed downward in the locked position, the lower end of the operating claw 121 is lowered. Is the offset member cam portion 53
FIG. 6 shows a state in which the right end of the upper support portion 49 of the offset member 48 abuts on the threading positioning member 52 from above, in contact with the inclined portion 53a of FIG. Thus, the engagement mechanism 117 is configured to be switched to the release position and the release operation is performed. Working claw
When the switch 121 is switched to the release position, the threading slider 40 and the offset member 48 return upward from the lower limit position shown in FIG. 6 by the urging forces of the compression coil springs 46 and 47.

The stopper 123 will be described with reference to FIG.
8, a stopper shaft 128 is supported at the left end of the bracket 125 in the front-rear direction, and a stopper 123 having a substantially inverted L-shape in side view is pivotally supported by the stopper shaft 128. The stopper 123 includes a vertical portion 129 that extends substantially vertically downward from the stopper shaft 128 and a stopper shaft.
128, a horizontal portion 130 extending substantially horizontally rightward and above the needle bar 18, and the tension coil spring for urging the vertical portion 129 and the horizontal portion 130 in the clockwise direction in FIG.
126 (see FIG. 10). At the lower end of the vertical portion 129, an inclined portion 131 is formed which is inclined diagonally leftward as it goes downward.

A stopper 132 (corresponding to a step) is formed at the left end portion where the inclined portion 131 and the vertical portion 129 intersect.
At the lower end of the threading slider operating member 119, a stopper engaging portion 119a engageable with the stopper portion 132 from above.
Are formed. Upper end of needle bar 18, stopper 12
3 is in the appropriate range from (a) to (b) (see FIG. 8), when the threading slider operating member 119 is moved downward from the upper limit position shown in FIG.
The stopper engaging portion 119a comes into contact with the inclined portion 131 of the stopper 123, and then the guide wall 119b of the threading slider operating member 119 slides against the left end of the inclined portion 131.

As the threading slider operating member 119 moves downward, the stopper 123 swings counterclockwise against the urging force of the extension coil spring 126, so that the threading slider operating member 119 is moved from the upper limit position in FIG. Can be moved to the lower limit position shown in FIG. When the upper end of the needle bar 18 is out of the proper range, the stopper 123 swings further clockwise from the position (b) (see FIG. 8). Even if the threading slider operating member 119 is moved downward in this state, the stopper engaging portion 119a engages with the stopper portion 132, so that the threading slider operating member 119 cannot move.
Threading is prohibited.

As shown in FIG. 7, the guide wall 119b of the threading slider operating member 119 is formed by the inclined portion 131 of the stopper 123.
, The height of the horizontal portion 130 of the stopper 123 is regulated, and a minute gap S is formed between the upper end of the needle bar 18 at the uppermost position and the horizontal portion 130. The impact noise between the stopper 123 and the stopper 123 is prevented.

Next, the thread tension device 9 and the interlocking mechanism 134 for the thread tension device 9 will be described. The interlocking mechanism 134 is a mechanism for opening the pair of thread tension discs 133 by the upper thread cassette 2 during the operation of attaching the upper thread cassette 2 to the cassette attaching section 3 and closing the thread tension disc 133 when the attaching operation is completed. It is. As shown in FIGS. 4, 10, 16, and 37 to 45, when the upper thread cassette 2 is mounted on the cassette mounting portion 3, the thread tensioner 9 is provided in the thread tensioner accommodation portion in the cassette case 57. Enters 57c. The thread tension controller 9 includes a pair of thread tension plates 133, a shaft member that supports the thread tension plates 133,
An operation plate 139 on the rear side of the rear thread tension plate 133, a spring member for elastically urging the rear thread tension plate 133 and the operation plate 139 forward, and the upper thread 24 near the thread tension plate 133 Thread tension spring 135 that supports elastically and thread tension dial 136 for adjusting spring force
It is of a general structure with such features.

As shown in FIGS. 37 to 45, the interlocking mechanism 13
4 is a cam portion 13 formed on the rear side of the upper thread cassette 57.
7, a vertical lever-like cam follower 138, and a rotating arm 151. In the upper half of the rear wall of the cassette main body 60, a cam portion 137, such as a ridge, which projects slightly rearward, is formed. A bracket 141 is formed on an upper portion of a frame 140 supporting the thread tensioner 9, and a middle portion of the cam follower 138 in the longitudinal direction of the cam follower 138 is rotatably supported by a horizontal pin oriented in the left-right direction. The cam follower 138 is formed by a torsion spring 144 as shown in FIG.
At 1 it is urged clockwise.

A roller 142 is provided at the upper end of the cam follower 138.
Is rotatably pivoted. A slit 143 (see FIG. 14) for projecting the cam portion 137 of the upper thread cassette 57 rearward is formed on the left side portion of the rear wall of the cassette mounting portion 3,
A roller 142 can contact a cam portion 137 projecting rearward from the slit 143. The right end of the rotating arm 151 is connected to the lower plate of the base plate 155 with a vertical pin and can be rotated horizontally. The lower end of the cam follower 138 is located on the rear surface of the left end of the rotating arm 151. , So that the projection 151a of the rotating arm 151 can contact the operation plate 139.

By appropriately setting the shape of the cam portion 137 and the position of the roller 142, the thread tension plate 133 is opened during the installation of the upper thread cassette 57, and the pair of the thread tension plate 133 and the thread tension spring 135 are moved. The thread tension tray 133 is closed when the thread is hooked, and then when the upper thread cassette 57 is completely mounted. That is, when the upper thread cassette 57 is mounted on the cassette mounting section 3 and the upper thread cassette 2 reaches a predetermined distance above the thread tensioner 9, the roller 142 rides on the cam portion 137 and the cam follower 138 is moved to the position shown in FIG. , The thread tension tray 133 is opened by the rotating arm 151 and the operating plate 139.

When the upper thread cassette 57 descends in this state, the upper thread 24 between the second and third guide portions 71 and 72 is hooked between the pair of thread tension discs 133, and thereafter the upper thread is threaded. When the cassette 57 is in the mounting completed state, the cam portion 137 is lowered and the roller 142 is not pushed rearward, so that the rotating arm 151 returns and rotates backward, the operating plate 139 returns and moves backward, and a pair of thread The tone plate 133 is closed. The operation of the interlocking mechanism 134 when the upper thread cassette 57 is mounted is determined by the position of the presser lifting lever 29 (the lower rotation position or the upper rotation position).
Occurs regardless of

Next, a mechanism for opening the pair of thread tension discs 133 by operating the presser lifting lever 29 is a well-known mechanism, as in the case of a normal sewing machine. As shown in FIGS. 37 to 45, the upper end of the presser lifting lever 29 is rotatably supported by the machine frame, and the upper end of the engagement arm 152 engaged with the cam portion 29a of the presser lifting lever 29 is also provided. It is pivotally supported by the machine frame. The engagement arm 152 is a connecting rod
153 is connected to the rear end of the horizontal triangular plate 154. The triangular plate 154 is disposed below the lower plate of the base plate 155 on the machine frame side, and the left end of the front end of the triangular plate 154 is a base plate.
155 is pivotally attached to the lower plate with a vertical pin,
The right end of the front end of the triangular plate 154 is in contact with the operating plate 139.

Accordingly, when the presser lifting lever 29 is in the downward rotation position, the connecting rod 153 is not pulled to the right, so that the triangular plate 154 does not rotate, and the thread tension plate 133 remains closed. When the presser lifting lever 29 is switched to the upward rotation position, the connecting rod 153 is pulled rightward, so that the triangular plate 154 rotates and the thread tension tray 133 is opened.

Next, the operation of the sewing machine 1 and the operation of the upper thread cassette 2 will be described. As shown in FIGS. 14 and 23 to 27, in a state where the upper thread cassette 2 is not mounted on the cassette mounting section 3, the opening / closing lid 61 of the upper thread cassette 2 is opened and the thread spool 62 is inserted into the thread spool holding section 58. Installing. Next, the upper thread 24 pulled out from the thread spool 62 is hung on the first guide portion 69,
It is hung on the thread guide portion 80 a of the first holding portion 70 and pressed by the leaf spring 81. Next, the upper thread 24 is connected to the second and third guide portions 7.
The guide pins 89 of the second holding portion 73
And the thread holding plate 90.

Next, the operation button 94a is pressed with a finger against the urging force of the leaf spring member 91 to separate the guide pin 89 from the thread holding plate 90, and then the upper thread 24 is moved outside by a predetermined length. Then, the pressing of the operation button 94a is released, and the upper thread 24 is held by the second holding portion 73,
The opening / closing lid 61 is closed. Note that, in order to make the procedure for hooking the thread onto the upper thread cassette 2 easier to understand, the first guide portion 69 and the first holding portion 7 are provided.
A threading order indication mark may be attached near each of the 0, the second and third guide portions 71 and 72, and the second holding portion 73, and the threading may be performed according to the order of the marks.

On the other hand, when the sewing machine 1 is in the sewing stopped state, the needle bar 18 is normally stopped at the needle upper position, and
Is stopped at a substantially middle position on the thread tightening side shown in FIG. In this state, the upper thread cassette 2 is mounted on the cassette mounting section 3 from above. Since the cassette mounting section 3 is open both upward and downward, the upper thread 24 pulled out about 20 cm from the thread outlet 68 of the upper thread cassette 2 hangs vertically below the cassette mounting section 3. At the start of sewing, the thread hook 26 of the balance 25 rises from the substantially middle position on the thread tightening side and then descends.

As shown in FIGS. 15 and 16, while the upper thread cassette 2 is being mounted, the engaging portion 112 of the upper thread cassette 2
Stops the upper thread cassette 2 once in contact with the lever portion 120a. At this time, as shown in FIG. 15, the upper thread 24 between the third guide portion 72 and the second holding portion 73
108 and is hooked on the thread hook 26 of the balance 25. In this case, since the second holding portion 73 gives stronger passage resistance than the first holding portion 70, the upper thread 24 is not pulled back into the cassette 2 and the upper thread 2
4 is fed out in the required amount. Incidentally, a pair of mating marks 146 for confirming the movement stop position are provided on the upper thread cassette 2 and the sewing machine 1.

Next, the upper thread 24 hanging downward from the thread outlet 68 of the upper thread cassette 2 is sequentially hooked on the needle bar thread hook 147 and the thread guide 36a. After being clamped by pressure, the yarn end is cut with a yarn cutting blade (not shown). Next, as shown in FIG. 16, and the needle thread cassette 2 Tensile pushed down downward against the biasing force of the coil spring 126, the operation of the needle thread cassette 2 in the automatic threading mechanism 10 via a transmission mechanism 115 The thread is transmitted and the upper thread 24 is passed through the needle hole 19a. In parallel with this, since the upper thread cassette 57 moves relatively downward with respect to the balance 25, the thread path between the third thread guide portion 72 and the second holding portion 73 becomes longer. Of the upper thread 24 is performed.

At this time, as described above, the thread tension plate 133 of the thread tensioner 9 is opened by the interlocking mechanism 134, and the upper thread 24 between the second and third guide portions 71 and 72 is moved between the thread tension plates 133. Is threaded on the thread tension spring 135. Since a constant tension is applied to the upper thread 24 between the two portions by the first holding portion 70 and the second holding portion 73, the balance 25, the thread tension plate 133, the thread tension spring 135
The upper thread 24 is securely hooked. Second holding portion 73
Gives a higher passing resistance to the upper thread 24 than the first holding section 70, so that the upper thread 24 does not flow backward through the second holding section 73 and is drawn back into the cassette 2. An appropriate amount of the upper thread 24 is reliably fed from the thread spool 62. In addition, since the upper thread 24 between the first holding section 70 and the second holding section 73 does not slack, the upper thread 24 does not become entangled with the yarn.

As shown in FIGS. 19 and 20, in a state where the upper thread cassette 2 is completely mounted on the cassette mounting section 3 (ie, a state where the engaging section 112 is engaged with the receiving section 109 from above). The thread tension tray 133 is closed by the interlocking mechanism 134, and the threading shaft 31 and the slider guide shaft 32 return upward to the needle hole 19a while the threading slider operating member 119 is held at the lowest position by the upper thread cassette 2. Is passed through the upper thread 24. As shown in FIG. 20, the operation button 94a is pushed leftward by the thread release cam 95, the guide pin 89 is separated from the thread holding plate 90, and the second holding portion 73 is opened, and the upper thread is released. 24 is released, and the sewing machine is ready for sewing.

Further, even when the pair of thread tension discs 133 is closed and the second holding portion 73 is opened in a state where the mounting of the upper thread cassette 57 is completed, the upper thread 24 is held by the first holding portion 70. And the upper thread 24 is provided with a passage resistance, so that the upper thread 24 in the upper thread cassette 57 does not become entangled with the thread by the thread. as a result,
Thread breakage due to thread tangling during sewing is less likely to occur. When the upper thread cassette 2 is mounted on the cassette mounting section 3, the thread guide member 106A and the thread hooking section 26 of the balance 25 project into the upper thread cassette 57, and the thread hooking section 26 of the balance 25 moves inside the upper thread cassette 2. Can be reciprocated substantially vertically.

As described above, the sewing can be performed while the upper thread 24 is supplied from the thread spool 62 in a state where the upper thread cassette 57 is mounted on the cassette mounting section 3. When removing the upper thread cassette 2 from the cassette mounting portion 3 in order to change the thread color of the upper thread 24 or to replenish the upper thread 24, push the lower end of the upper thread cassette 2 upward with a finger. Can be easily removed.

After the removal, the upper thread cassette 2 contains
Since the slack yarn removed from the balance 25 and the thread tensioner 9 remains,
By pressing the operation button 94a with a finger, the second holding portion 73 is switched to the open state, and in this state, the slack yarn in the upper thread cassette 2 is pulled out and wound around the outer periphery of the cassette.
The thread end portion of No. 4 is temporarily fixed to the thread stopper 104 or the thread stopper 104A. Thereafter, the operation button 94 is returned to bring the second holding portion 73 into a closed state.

The sewing machine 1 and the upper thread cassette 2 according to this embodiment have the following effects. 1) Since the thread spool 62 is accommodated in the upper thread cassette 2 and the thread spool 62 can be exchanged by exchanging the upper thread cassette 2,
The replacement of the upper thread 24 has been simplified. In particular, the upper thread cassette 2
In conjunction with the mounting operation of the thread, the thread is automatically hooked on the thread hooking section 26 of the balance 25, the thread tension plate 133 of the thread tensioner 9 and the thread tension spring 135, so that the operation of the thread hooking becomes very simple. It can be performed efficiently. Since the automatic threading mechanism 10 is operated in conjunction with the mounting operation of the upper thread cassette 2 to automatically thread the needle thread 29a, the threading becomes very simple, and the upper thread 24 can be replaced quickly. It can be performed efficiently.

In particular, when the sewing is stopped, the needle bar 18 is stopped at the position above the needle, and the thread hooking portion 26 of the balance 25 is stopped at the position on the thread tightening side, without changing the position of the balance 25, Since the upper thread cassette 2 can be attached and the thread can be hooked on the thread hooking section 26 of the balance 25 and the thread tensioner 9, the operation of attaching the upper thread cassette 2 and thread hooking can be performed very easily and efficiently. . In addition, the upper thread cassette 2 can be mounted on the cassette mounting portion 3 by linearly moving the upper thread cassette 2 from above, and the upper thread cassette 2 in the mounted state can be linearly moved upward to be removed. The attachment / detachment operation of the cassette 2 is easy, and the upper thread cassette 2 can be quickly replaced.

Further, the cassette case 5 of the upper thread cassette 2
Since the thread 7 is transparent and the thread color of the thread spool 62 inside can be easily identified, it is convenient when replacing the upper thread 24 or the upper thread cassette 2. Thread spool 62 inside upper thread cassette 2
A concave portion 65 is formed in the support wall 63 that supports the thread spool 62.
Can be easily removed from the thread spool holding portion 58.

2) The thread spool 62 is held in the upper thread cassette 2 with its axis centered vertically, the upper thread 24 is fed upward from the thread spool 62, and guided to the thread outlet 68 through the thread path 59. With such a configuration, the width of the upper thread cassette 2 in the left-right direction can be reduced. Alternatively, the upper thread cassette 2 is set by setting the axis of the thread spool 62 and the feeding direction of the upper thread 24 from the thread spool 62 substantially parallel to the reciprocating direction of the thread hooking portion 26 of the balance 25.
Is mounted on the cassette mounting section 3,
The width in the left-right direction of the upper thread cassette 2 and the width in the left-right direction of the cassette mounting portion 3 can be reduced.

As described above, since the upper thread cassette 2 is a small one close to a vertically long rectangular parallelepiped having a small width in the left-right direction,
The cassette mounting section 3 could be arranged in the reciprocating movement area of the thread hooking section 26 of the balance 25 and the left side thereof, that is, on the arm head. As a result, the cassette mounting section 3 can be formed in an area overlapping the reciprocating area of the thread hooking section 26 of the balance 25, which is advantageous in terms of space. Also, the arm 6
The cassette mounting portion 3 can be disposed as rearwardly as possible without interfering with the internal mechanism of the upper thread cassette 2, so that the upper thread cassette 2 does not protrude from the front surface of the arm portion 6 in a state where the upper thread cassette 2 is mounted. The appearance of the arm 6 does not deteriorate, and the design flexibility of the front surface of the arm 6 can be secured.

3) At the upstream of the yarn path 59 in the upper yarn cassette 2, there is provided a first holding portion 70 for constantly providing resistance to passing the upper yarn 24, and the first holding portion 70 with the upper yarn cassette 24 mounted is provided. Since the upper thread 24 between the thread tensioner 9 and the thread tensioner 9 is maintained in a tensioned state, it is possible to prevent the occurrence of tangling of the thread due to the twisting of the thread, and to prevent the thread from being broken or the string being twisted due to the tangling of the thread during sewing.

The second holding portion 7 is located near the yarn outlet 68.
3 is provided so as to provide a passing resistance to the upper thread 24 before or after the mounting of the upper thread cassette 2, and the second holding portion 73 provides a stronger passing resistance than the first holding portion 70. The upper thread 24 is not unwound unnecessarily during the handling of the cassette 2, and when the upper thread cassette 2 is installed, the upper thread is threaded when the thread is hooked on the thread hook 26 of the balance 25 and the thread tensioner 9. It can be reliably fed from the piece 62.

When the upper thread cassette 2 is not mounted, the operation button 94a is operated with a finger to operate the second holding portion 7a.
3 is released, and the upper thread 24 can be fed out freely. After the upper thread cassette 2 has been mounted, the operation button 94
a is pressed by the upper thread release cam 95 to switch the second holding section 73 to the open state. Therefore, the passage resistance of the second holding section 73 does not act on the upper thread 24 during sewing, and the feeding of the upper thread 24 is stopped. Become smooth. When the upper thread cassette 2 is removed from the cassette mounting section 3, the upper thread 24 extending outside the cassette case 57 can be wound around the outer surface of the cassette case 57, and the thread end portion can be stopped by the thread stoppers 104 and 104A. , Very convenient.

4) The first guide portion 6 is provided at the top of the upper thread cassette 2.
9, the front and rear elongated openings 77 and 78, and the thread guide portion of the guide pin 75 facing in parallel with the openings 77 and 78, so that the upper thread 24 is provided.
Can freely move along the guide pin 75, and the upper thread 24
Can be smoothly fed out from the thread spool 62 by drawing an arc without resistance, and the upper thread from the thread spool disposed outside the upper thread cassette 2 is introduced into the upper thread cassette 2 through the openings 77 and 78. Then, the yarn exit 6 is controlled by the yarn path 59 therein.
8 and can be used for sewing. Therefore, needle 1
At the time of sewing with two needles by attaching two needles instead of the needle 9, the needle is held by the thread spool 62 in the upper thread cassette 2 and the thread segment holder at the top of the arm 6 outside the upper thread cassette 2. The upper thread can be supplied from the completed thread spool to perform sewing.

5) The thread tension device 9 is opened in conjunction with the mounting operation of the upper thread cassette 2, and the interlocking mechanism 134 for closing the thread tension tray 133 after the upper thread cassette 2 is mounted is provided. The thread can be hooked on the thread tensioner 9 in conjunction with the mounting operation of the upper thread cassette 2. In addition, the cassette mounting section 3
Since the thread tension device 9 is disposed at the lower end portion of the thread tension device 9, it is particularly advantageous to thread the thread tension device 9 in conjunction with the mounting operation of mounting the upper thread cassette 2 to the cassette mounting portion 3 from above.

6) The balance mechanism 8 has a specific structure.
It is suitable for threading. That is, a thread guide member 106A is provided which forms a curved thread guide gap 108 extending along the entire length of the movement locus of the thread hooking section 26 of the balance 25, and the upper thread 24 is fed from the inlet 108a at the upper end of the thread guide gap 108. It is configured such that it can be introduced and threaded on the threading portion 26. for that reason,
Since the thread introduction port 108a is at a position where it does not retreat backward from the movement locus of the thread hooking section 26, the thread hooking section 26 of the balance 25 is moved to the above-described thread tightening side position (a position corresponding to the needle stop position of the needle bar 18). ), The thread can be hooked on the thread hooking section 26 in conjunction with the mounting operation of the upper thread cassette 2 on the cassette mounting section 3.

In addition, the yarn guide gap 108 is
Over the entire length of the movement trajectory of the thread guide member 106A.
The pair of thread guides 106 forming the U-shaped guide 25
a so that the upper thread 24 can be threaded to the thread guide 106 even if the balance 25 reciprocates up and down during sewing.
, And does not come off from the threading portion 26. Further, since the upper end of the rear yarn guide 106 is rotatably pivotally supported, the pair of yarn guides 106 can be guided by the U-shaped guide portion 25a of the balance 25. The tool 106 can be made of a material that is easy to process, such as a linear member, at low cost.
The sliding resistance hardly acts between the shape guide portion 25a and the pair of thread guides 106, and the sliding noise hardly occurs.

[0116]

According to the first aspect of the present invention, a thread hook portion is formed at the tip end of the balance, and the thread guide gap extends in a curved shape along the entire length of the movement locus of the thread hook portion of the balance. Is provided so that the upper thread can be introduced into the thread guide gap from the direction of the movement locus of the balance, so that the upper thread hooked on the thread hook portion of the balance is located in the thread guide gap, The thread is guided by the thread guide member so as not to come off from the thread hooking portion of the balance.

With the balance held at the position on the thread tightening side,
By introducing the upper thread into the thread guide gap from the direction of the movement locus of the balance, the upper thread can be easily hooked on the thread hooking portion of the balance. The upper end of the thread guide gap is located at substantially the same position as the upper end of the movement locus of the thread hooking portion of the balance, and is located at a position where it does not largely retreat from the frontmost portion of the movement locus of the thread hooking portion. Therefore, while the balance is held at the position on the thread tightening side, the upper thread can be thread-hung on the thread-hook portion of the balance in conjunction with the mounting operation of the upper thread cassette, etc. It is also possible to prevent the yarn path from becoming complicated.

According to the second aspect of the present invention, a U-shaped guide portion is formed in the distal end side portion of the balance in plan view, and extends along the entire length of the movement trajectory of the distal end portion of the balance and the thread is formed. A pair of thread guides is provided spaced apart in the front and back with a guide gap, and the pair of thread guides is slidably inserted through the U-shaped guide portion. When the upper thread is introduced from the upper end of the thread guide gap and hangs on the U-shaped guide section, the upper thread is located in the thread guide gap and guided so as not to come off from the U-shaped guide section.

In the same manner as in the first aspect, the upper thread is easily introduced into the U-shaped guide portion by introducing the upper thread into the thread guide gap from the direction of the movement locus of the balance while holding the balance at the position on the thread tightening side. You can hang the thread. The upper end of the yarn guide gap is located at substantially the same position as the upper end of the movement trajectory of the U-shaped guide portion, and is located at a position where it does not largely retreat from the frontmost portion of the movement trajectory of the U-shaped guide portion. Therefore, while the balance is held at the position on the thread tightening side, the upper thread is moved in conjunction with the mounting operation of the upper thread cassette or the like.
The thread can be hooked on the shape guide portion, and the thread route in the upper thread cassette can be prevented from becoming complicated.

According to the third aspect of the present invention, a thread catching portion for threading the upper thread from above is formed at a portion of the U-shaped guide portion corresponding to a portion between the pair of thread guides, and is formed in the thread guide gap. Since the upper thread can be introduced from above, the upper thread can be hooked into the thread hooking section of the U-shaped guide section by introducing the upper thread into the thread guide gap from above, and the upper thread is held in the thread hooking section While being guided by the pair of yarn guides so as not to come off the yarn hooking portion. The other effects are the same as those of the second aspect.

According to the fourth aspect of the present invention, since the pair of thread guides is constituted by one linear member, the number of members is reduced.
For example, it can be manufactured using an easily processable material such as a wire, so that the structure is simplified and the yarn introduction portion can be formed at the upper end of the yarn guide gap. The upper end portion of the rear thread guide is rotatably attached to the sewing machine frame, and the pair of thread guides is guided by the U-shaped guide, so that the U-shaped guide and the pair of thread guides are provided. The sliding resistance of the tool is reduced, and the sliding noise is hardly generated. Other effects similar to those of the second or third aspect are exhibited.

[Brief description of the drawings]

FIG. 1 is a front view of an electronically controlled sewing machine and a needle thread cassette according to an embodiment of the present invention.

FIG. 2 is a plan view of the sewing machine with the upper thread cassette removed.

FIG. 3 is a longitudinal sectional view showing an internal structure near a cassette mounting portion.

FIG. 4 is a plan sectional view showing an internal structure and the like near a cassette mounting portion.

FIG. 5 is a front view of a needle bar vertical movement mechanism, an automatic threading mechanism, and the like.

FIG. 6 is a diagram corresponding to FIG. 5, showing a state immediately before threading.

FIG. 7 is a diagram corresponding to FIG. 5, showing a relationship between a needle bar and a stopper.

FIG. 8 is a diagram corresponding to FIG. 5, illustrating an appropriate height range of the needle bar.

9A is a perspective view showing a state immediately before threading by a threading hook, FIG. 9B is a perspective view showing a state immediately after threading,
(C) is a sectional view of an essential part in a state where the threading hook is raised after threading.

FIG. 10 is a longitudinal sectional side view of a threading slider operating mechanism and an upper thread cassette;

FIG. 11 is a longitudinal sectional side view of a main part showing a balance mechanism and a cassette mounting part.

FIG. 12 is a vertical sectional side view of a main part showing a movement range of a thread hooking portion of the balance.

FIG. 13 is a diagram corresponding to FIG. 12, showing a range in which a yarn can be hooked on a yarn hooking portion.

FIG. 14 is a front view of the upper thread cassette (in a state immediately before mounting) and a cassette mounting portion.

FIG. 15 is a front view of the upper thread cassette (during mounting) and a cassette mounting portion.

FIG. 16 is a longitudinal sectional side view of the upper thread cassette (in the middle of mounting) and a cassette mounting portion.

FIG. 17 is a front view of the upper thread cassette (immediately before completion of mounting) and the arm head.

FIG. 18 is a partially enlarged sectional view of a second holding portion and a cam.

FIG. 19 is a front view of the upper thread cassette (in a completed mounting state) and an arm head.

FIG. 20 is a view showing the second holding portion (open state) and the cam;
FIG.

FIG. 21 is a cross-sectional view of the upper thread cassette mounted on the cassette mounting section.

FIG. 22 is a longitudinal sectional side view of the upper thread cassette (in a completed mounting state) and a cassette mounting portion.

FIG. 23 is a front view of the upper thread cassette (opening / closing lid opened).

FIG. 24 is a vertical sectional side view of the upper thread cassette.

FIG. 25 is a plan view of the upper thread cassette.

FIG. 26 is a bottom view of the upper thread cassette.

FIG. 27 is a partially cutaway cross-sectional plan view of the upper thread cassette showing a downstream portion of the thread path.

FIG. 28 is a longitudinal sectional side view of the cassette body and a thread spool (in a state before mounting).

FIG. 29 is a longitudinal sectional side view of the cassette main body and the thread spool (after attachment).

FIG. 30 is a front view of the upper thread cassette (opening / closing lid opened).

FIG. 31 is a bottom view of the upper thread cassette (open / close lid open state).

FIG. 32 is a plan view of the cassette main body showing the first guide portion.

FIG. 33 is a bottom view of the upper thread cassette showing the second and third guide portions and the second holding portion.

FIG. 34 is a cross-sectional view of the cassette main body showing the second and third guide portions and the second holding portion.

FIG. 35 is a front view of the upper thread cassette for explaining the procedure of thread clamping.

FIG. 36 is a side view of the upper thread cassette showing a thread stopper and the like.

FIG. 37 is a front view of a presser lifting lever, a thread tensioner, an interlocking mechanism, and the like.

FIG. 38 is a side view of a presser lifting lever, a thread tensioner, an interlocking mechanism, and the like.

FIG. 39 is a plan view of a presser lifting lever, a thread tensioner, an interlocking mechanism, and the like.

FIG. 40 is a view corresponding to FIG. 37, showing a state when the upper thread cassette is mounted.

FIG. 41 is a diagram corresponding to FIG. 38, showing a state when the upper thread cassette is mounted.

FIG. 42 shows a state in which the upper thread cassette is being mounted.
FIG.

FIG. 43 is a view corresponding to FIG. 39, showing a state in which the upper thread cassette has been mounted.

FIG. 44 is a view corresponding to FIG. 37, showing a state in which the upper thread cassette has been mounted.

FIG. 45 is a view corresponding to FIG. 38, showing a state in which the upper thread cassette has been mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sewing machine 2 Needle thread cassette 3 Cassette mounting part 6 Arm part 8 Balance mechanism 9 Thread tensioner 24 Needle thread 25 Balance 25a U-shaped guide part 26 Thread hooking part 27 Balance movement area 57 Cassette case 58 Thread piece holding part 59 Thread path 62 Thread spool 65 Concave part 68 Thread outlet 69 First guide part 70 First holding part 71 Second guide part 72 Third guide part 73 Second holding part 80 Pressing plate 81 Leaf spring 82 Thread generation preventing mechanism 84 Guide pin 90 Thread holding Board 91 Leaf spring member 104A Thread stopper 106 Thread guide 106A Thread guide member 108 Thread guide gap 108a Inlet 133 Thread tension plate 135 Thread tension spring

Claims (4)

[Claims] 1. A balance mechanism having a balance for picking up an upper thread in synchronization with a sewing operation of a sewing machine, wherein a thread hook portion capable of threading is formed at a tip end of the balance, and a thread hook portion of the balance is provided. A thread guide member that forms a thread guide gap extending in a curved shape along the entire length of the movement locus; and a needle thread can be introduced into the thread guide gap from the direction of the movement locus of the balance. Balance mechanism. 2. A balance mechanism provided with a balance for picking up an upper thread in synchronization with a sewing operation of a sewing machine, wherein a U-shaped guide portion is formed in a front end portion of the balance in a plan view, and a tip of the balance is provided. A pair of thread guides extending in a curved shape along the entire length of the movement trajectory of the section and spaced apart back and forth with a thread guide gap, and a pair of thread guides can be slid relative to the U-shaped guide section. The balance mechanism of the sewing machine, characterized in that it has been inserted through. 3. A thread catching portion for threading an upper thread from above at a portion between the pair of thread guides of the U-shaped guide, and introducing the upper thread into the thread guide gap from above. 3. The balance mechanism of the sewing machine according to claim 2, wherein the balance mechanism is configured to be capable. 4. The pair of thread guides is formed of a single linear member having one end continuous, and the other end of the rear thread guide is rotatable with respect to the sewing machine frame. The balance mechanism of the sewing machine according to claim 2 or 3, wherein the U-shaped guide portion is attached to guide the pair of thread guides.