JPH05192482A - Thread sweeping and holding device for sewing machine - Google Patents

Abstract

PURPOSE:To provide the title device whereby needle thread severed under a throat plate is surely swept up above a presser foot and is surely held for the next sewing. CONSTITUTION:A thread sweeping member 27 which enters the space between sewing needles and a presser foot and retracts therefrom after thread cutting, and which has a thread sweeping hook 27a, is provided. A V-shaped needle thread guiding part 36b is formed at the free end of a thread catching spring 36 which is in slide contact with the thread sweeping member 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread wiping / holding device of a sewing machine capable of wiping the end portion of a needle thread cut by a thread cutting device to the upper side of a presser foot and holding the needle thread end portion.

[0002]

2. Description of the Related Art Conventionally, various sewing machines such as a zigzag stitch sewing machine and a decorative stitch sewing machine are provided with a thread trimming device immediately below a needle plate of a sewing machine bed portion, and at the end of sewing, a bobbin thread and a stitch hole of a sewing needle are formed. A needle thread extending downward from the needle thread has been put to practical use automatically or manually. Furthermore,
A thread trimming device is provided, and as shown in FIG. 9, the end portion 13a of the needle thread 13 cut by the thread trimming device is engaged with the hook portion 27a of the thread wiping member 27 to allow the work cloth W and the presser foot 8 to move. The needle thread end portion 13a is wiped to the upper side, and the sewing thread 1
1 and the hook portion 27 provided on the side of the thread gripping spring 100.
A sewing machine provided with a thread wiping / holding device for holding with a has been put into practical use.

That is, in this thread wiping and holding device,
At the end of sewing, the hook portion 27a of the thread wiping member 27 is moved in the direction of arrow G from the thread holding position shown by the solid line on the side of the sewing needle 11 at the needle up position to the thread catching position near the bottom of the sewing needle 11 shown by the two-dot chain line. By engaging the hook portion 27a with the cut needle thread end portion 13a extending downward by a predetermined length from the eyelet 11a, and then moving the hook portion 27a in the arrow H direction to the thread holding position. The needle thread end portion 13a is provided so as to abut on the hook portion 27a and the lower surface of the hook portion 27a, and has a rectangular tip portion.
It is held by the curved yarn holding portion 100a. On the other hand, when the sewing needle 11 descends due to the start of sewing, the needle thread end portion 13
Since a is held by the thread holding portion 100a, the needle thread end portion 13a does not come off from the eyelet hole 11a, and the sewing is normally resumed. Reference numeral 14 is a presser bar with the presser foot 8 attached to the lower end.

[0002]

[Problems to be Solved by the Invention] However, the needle thread 1
When 3 is particularly thick and has elasticity, the needle thread end 13a is processed until the thread end comes off the work cloth W while the hook 27a is moving from the thread catching position to the thread holding position. Since it is stretched due to the frictional resistance with the cloth W, at the moment it comes off, it jumps up more than the position of the hook portion 27a in the moving direction of the hook portion 27a (the direction of arrow H),
As shown in FIG. 9, the thread gripping spring 100 is in a state of riding on one side edge. As a result, when the hook portion 27a moves to the thread holding position, the needle thread end portion 13a from the hook portion 27a to the thread end gets over the thread holding portion 100a while rotating and sliding due to the relative movement of the thread holding portion 100a. However, there is a problem that the needle thread end portion 13a cannot be held by the thread holding portion 100a and the needle thread end portion 13a comes out of the eyelet hole 11a and cannot be sewn when the sewing needle 11 descends at the start of the next sewing.

An object of the present invention is to be able to thread-displace the end of a cut needle thread to the upper side of a presser foot and to ensure that the thread-cleaned needle thread end is secured by a hook portion of a thread-displacing member and a thread-grasping spring. To provide a thread wiping / holding device for a sewing machine that can hold the thread.

[0004]

A thread removing and holding device for a sewing machine according to the present invention includes at least a needle bar having a lower end to which a sewing needle can be attached, and a needle bar drive mechanism for vertically reciprocating the needle bar. In a sewing machine equipped with a cloth feed mechanism for feeding the work cloth in synchronism with the vertical movement of the needle bar and a thread cutting device for cutting at least the needle thread under the needle plate, It has a hook that can engage with the needle thread extending from the eyelet hole of the sewing needle to the needle plate in the needle up stop state after cutting the needle thread. And a thread wiping member that is swingable over a thread holding position approximately on the side of the sewing needle, and a thread wiping member that is disposed so as to contact the lower surface of the thread wiping member that is located at the thread holding position, A thread gripping bar that holds the end of the needle thread cut by the thread cutting device in cooperation with the wiping member. And a driving means for driving the thread wiping member over the thread catching position and the thread holding position, and the thread wiping member is provided at a tip side portion of the thread gripping spring closer to the sewing needle than the thread holding portion. A V-shaped guide portion is provided for guiding the needle thread hanging downward from the hook portion when moving from the yarn catching position to the yarn holding position.

[0005]

In the thread wiping / holding device of the sewing machine according to the present invention, the hook portion of the thread wiping member is substantially lateral to the sewing needle in the needle suture stop state in the needle suture stop state after the needle thread is cut by the thread trimming device. When the thread wiping member is swung by the drive means so as to reach the thread catching position near the lower side of the sewing needle from the thread holding position, the hook portion engages the needle thread extending from the eyelet hole of the sewing needle to the needle plate. . In this state, when the thread wiping member moves from the thread catching position to the thread holding position, the needle thread that hangs downward from the hook portion is a V-shaped guide provided on the tip side portion closer to the sewing needle than the thread holding portion. Guided by the department. As a result, the direction in which the needle thread end part bounces when the thread end comes out of the work cloth is restricted to a narrow V-shaped area on the sewing needle side of the thread holding part,
Since the hook portion moves to the thread holding position, the needle thread end portion that hangs downward from the hook portion is arranged so as to contact the lower surface of the thread wiping member located at the thread holding position. And the thread wiping member cooperate with each other to surely hold.

[0006]

According to the thread wiping / holding device of the sewing machine of the present invention, as explained in the section [Operation], the thread wiping / holding device includes the thread wiping member, the thread gripping spring, and the driving means. And a V-shaped guide portion is provided at the tip end portion of the thread gripping spring closer to the sewing needle than the thread holding portion. Therefore, when the needle thread is wiped by the thread wiping member, Even when the end portion bounces greatly, the needle thread end portion is guided by the guide portion and its rebound direction is restricted to a narrow V-shaped area on the sewing needle side of the thread holding portion. The thread holding portion of the thread gripping spring and the thread wiping member can cooperate to reliably hold the thread.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a thread wiping / holding device of a decorative sewing machine provided with a thread cutting device. As shown in FIGS. 1 to 8, the decorative sewing machine 1 is
The sewing machine bed portion 2, a pedestal portion 3 erected from the right end portion of the bed portion 2, and an arm portion 4 extending leftward from the pedestal portion 3 so as to face the bed portion 2, The bed portion 2 has a feed dog up-and-down drive mechanism (not shown) for moving the feed dog 7 up and down, a feed tooth forward-backward drive mechanism (not shown) for moving back and forth, and a looper for reciprocally driving the looper 54 in a direction orthogonal to the cloth feed direction. The thread cutting device 6 for cutting the drive mechanism 40, the lower thread 55 of the looper 54 and the needle thread 13 of the sewing needle 11.
0, etc. are provided, and a needle bar drive mechanism for vertically moving a needle bar 9 on which three sewing needles 11 can be attached at the lower end, and a balance are vertically moved in synchronization with the vertical movement of the needle bar 9. A balance driving mechanism (not shown), a thread wiping / holding device 20 for wiping the needle thread 13 cut by the thread cutting device 60 above the presser foot 8 and holding the thread end portion 13a of the needle thread 13, are provided. There is.

Since the needle bar drive mechanism is similar to that of an ordinary sewing machine, a brief description will be given without showing it. One end of a connecting lever is attached to a needle bar crank fixed to an upper shaft which is rotationally driven by a sewing machine motor. It is rotatably connected, and the other end of the connecting lever is connected to the needle bar 9 via the needle bar holder, and the needle bar 9 is reciprocally driven up and down via the connecting lever by the rotation of the needle bar crank. A needle mount 10 is fixed to the lower end of the needle bar 9 as shown in FIG.
Three sewing needles 11 are removably attached at a predetermined interval in a direction orthogonal to the cloth feed direction. However, as shown in FIG. 2, the tip of the left sewing needle 11 is lower than the tip of the central sewing needle 11 by a predetermined dimension, and the tip of the right sewing needle 11 is higher than the tip of the central sewing needle 11 by a predetermined dimension. .. Incidentally, reference numeral 12 is a hole.

Next, the thread wiping and holding device 20 will be described with reference to FIGS. 2 to 5. The sewing machine frame 21 of the head 5 of the arm 4 is provided with a fixed plate 22 having a substantially crank shape in a front view. A rotary solenoid (hereinafter, simply referred to as a solenoid) 24 is fixed to the rear side of the right end portion of the fixing plate 22 with a screw 23, and the thread wiping lever 2 is attached to the left end portion thereof.
5 is rotatably supported by a screw 26, and a thread wiping lever 25
The base end of the thread wiping member 27 is fixed to the other end of the with a screw 28. Further, a rotary plate 30 is fixed to a drive shaft 29 of the solenoid 24, and the right end portion of a thread wiping link 31 arranged in the left-right direction is rotatably supported by a screw 32 on the rotary plate 30. At the same time, its left end is rotatably supported at one end of the thread wiping lever 25 by a screw 33. However, the rotating plate 30 is always biased in the clockwise direction in FIG. 2 by a winding spring (not shown) incorporated in the solenoid 24.

The tip of the thread wiping member 27 is shown in FIGS.
As shown in FIG. 5, a hook portion 27a having a guide groove 34 and an engagement hole 35 is formed, and the needle thread 13 extending downward from the eyelet 12 can be engaged with the hook portion 27a.
The thread gripping spring 36 made of a thin plate-shaped spring member is fixed to the fixing plate 22 with a screw 37 at the base end thereof, and the hook portion 2 of the thread wiping member 27 is provided near the tip of the thread gripping spring 36.
In order to hold the needle thread 13 in cooperation with 7a, an upwardly curved thread holding portion 36a is formed, and a hook portion 27a is engaged with the tip end portion on the sewing needle 11 side of the thread holding portion 36a. V-shaped guide portion 36b for guiding the needle thread 13 hanging downward
Are integrally formed.

Therefore, when the solenoid 24 is not driven, the rotary plate 30 and the thread wiping link 31 are positioned at the standby position shown by the solid line in FIG.
The hook portion 27a of the thread wiping member 27 is located at a thread holding position shown by a solid line on a substantially lateral side of the sewing needle 11 in the needle up stop state. When the solenoid 24 is driven after the needle thread 13 is cut by the thread cutting device 60 described later, the rotating plate 30
Is rotated to the rotation position shown by the chain double-dashed line, so that the thread wiping member 27 is moved through the thread wiping link 31 and the thread wiping lever 25.
Since it is swung to the position shown by the dotted line, the hook portion 27
a moves to the thread catching position near the bottom of the sewing needle 11 and
The needle thread end portion 13a extending downward from 2 is engaged (see FIG. 3). After that, when the driving of the solenoid 24 is stopped, the hook portion 27a returns to the thread holding position while the needle thread end portion 13a is engaged. At this time, the hook portion 27a
The needle thread end portion 13a that hangs downward from is restricted to a narrow V-shaped range of the guide portion 36b closer to the sewing needle 11 than the thread holding portion 36b, so that the hook portion 27a and the thread holding portion 36a cooperate with each other. Is securely held by. Incidentally, reference numeral 14 is a presser bar to which the presser foot 8 is detachably attached at the lower end, reference numeral 15 is a needle plate, and reference numeral W is a work cloth.

Next, the looper drive mechanism 40 for driving the looper 54 in the direction orthogonal to the cloth feed direction will be described with reference to FIG.
It will be explained based on. The lower shaft 41, which is arranged in the bed 2 in the left-right direction and is driven to rotate by a sewing machine motor in synchronization with the rotation of the upper shaft, has a front end portion of a connecting rod 43 extending in the front-rear direction via an eccentric cam 42. And a rear end portion of the connecting rod 43 is pivotally connected to a pivot arm 45 fixed to a pivot shaft 44 arranged in parallel with the lower shaft 41. On the other hand, the looper actuating shaft 46, which is disposed orthogonal to the lower shaft 41 and to which the looper mounting member 53 is fixed, is supported by the machine frame 21 so as to be rotatable and movable in the front-rear direction.

On the looper actuating shaft 46, an engaging body 47 having an engaging groove is rotatably and immovably supported in the front-rear direction, and an engaging piece 49 engaging with the engaging groove is rotatable. It is rotatably attached to the tip of a rotating arm 48 attached to the shaft 44. Further, the upper end of the swing arm 50 which is arranged in the vertical direction and rotates the looper actuating shaft 46 is rotatably fitted to the eccentric cam 51 fixed to the left end of the lower shaft 41, and the lower end thereof. The ball shaft portion 52a of the rotating arm 52 fixed to the looper actuating shaft 46 is fitted and connected to the portion. The base end of a looper 54, which is substantially U-shaped when viewed from the front, is attached to the looper attachment member 53 via a rod 54a.

Therefore, when the lower shaft 41 is rotated by the sewing machine motor, the connecting rod 43 reciprocates in the front-rear direction via the eccentric cam 42, and the pivot shaft 44 reciprocally pivots via the swing arm 45. The looper actuating shaft 46 is reciprocally moved in the front-rear direction through the engagement of the rotating arm 48, the engaging piece 49, and the engaging groove. On the other hand, the rotation of the lower shaft 41 causes the swing arm 5 to move.
Since 0 reciprocates in the substantially vertical direction via the eccentric cam 51, the looper operating shaft 46 is reciprocally pivoted via the pivot arm 52. As a result, the tip portion of the looper 54 is reciprocally moved in a direction orthogonal to the cloth feed direction in proportion to the amount of rotation of the looper operating shaft 46, and reciprocating motion corresponding to the amount of movement of the looper operating shaft 46 in the front-rear direction causes three movements. An elliptical locus is drawn so that the needle thread 13 of the book can be engaged.

Next, the thread cutting device 60 arranged in the bed portion 2 immediately above the looper drive mechanism 40 will be described with reference to FIGS. 7 to 8. A base plate 61 is horizontally arranged in the bed portion 2 and is screwed to a plurality of boss portions provided on the machine frame 21. This base plate 6
1, an upper knife lever 62 having a substantially fan shape in plan view and a lower knife lever 64 having a substantially crank shape are pivotally supported by screws 87. An upper knife 63 is fixed to the protruding portion 62a of the upper knife lever 62. The lower female lever 64 has a first
The base end of a curved lower knife 65 having a hook 65a and a second hook 65b formed at the tip is fixed, and the left end of the drive connecting rod 66 extending in the substantially left-right direction is rotated by a screw 67. Connected as possible. The right end of the drive connecting rod 66 is rotatably connected to an operating shaft 71 of a thread cutting drive mechanism 70 with a screw 68. A stroke adjusting portion 66a using a turnbuckle is provided at a part of the drive connecting rod 66.
Is provided, and the length of the drive connecting rod 66 can be adjusted by the stroke adjusting portion 66a.

Next, the thread cutting drive mechanism 70 will be described. The operating shaft 71 extending in the left-right direction is supported by a support member 72 attached to the machine frame 21 in a U-shape in plan view so as to be movable in the left-right direction. An operating lever 73 and a spring receiving member 74 are screw-fastened to the operating shaft 71 located inside the support member 72 with the operating shaft 71 inserted through the operating lever 71 and the spring receiving member 74, respectively. A compression spring 75 is externally mounted on the operating shaft 71. Therefore, the actuating shaft 71 and the actuating lever 73 are always elastically biased to the left (the direction of arrow B) by the spring force of the compression spring 75. Further, the actuating lever 73 is connected to a plunger 77 of a thread cutting solenoid 76 disposed in the left and right direction on the rear side of the machine frame 21, and the thread cutting solenoid 76 is attached to a mounting plate 78 fixed to the machine frame 21. Installed on.

Accordingly, when the thread trimming solenoid 76 is not driven, the operating lever 73 and the operating shaft 71 are located at the standby position shown by the solid line, so that the lower knife lever 64 is moved through the drive connecting rod 66 to the standby position shown by the solid line. Is located in. When the thread trimming solenoid 76 is driven, the operating lever 73 and the operating shaft 71 move in the direction of arrow A and are positioned at the operating position indicated by the chain double-dashed line, so that the lower female lever 64 simultaneously moves through the drive connecting rod 66. The lower knife 65 is rotated clockwise as indicated by the dotted chain line, and the lower knife 65 has its distal end positioned immediately above the looper 54 (see FIG. 8).
Rotate clockwise until. At this time, the first hook 6
The lower thread 55 of the looper 54 is engaged with 5a, and the needle thread 13 is engaged with the second hook 65b.

After that, when the thread cutting solenoid 76 is no longer driven, the operating lever 73 and the operating shaft 71 move and return to the standby position in the direction of the arrow B by the spring force of the compression spring 75, so that the lower female lever 64 simultaneously moves to the standby position. Turn to. During rotation of the lower knife lever 64 to the standby position, the lower thread 55 engaged with the first hook 65a and the needle thread 13 engaged with the second hook 65b are sequentially cut by the upper knife 63. Here, on the lower surface of the upper knife 63,
As shown in FIGS. 7 and 8, a thread holding spring 79 that abuts from below is fixed to the lower surface of the lower knife 65, and only the lower thread 55 cut by the upper knife 63 and the lower knife 65 and this thread holding spring 79. Held by.

By the way, a circular contact member 80 for contacting the lower female lever 64 is screwed to the upper female lever 62, and the spring receiving portion 62b of the upper female lever 62 and the base plate 61 are linearly bent a plurality of times. The spring 81 is stretched, and the upper female lever 62 is always elastically biased in the clockwise direction by the spring force of the spring 81. Further, in order to regulate the amount of clockwise rotation of the upper female lever 62,
The engaging portion 62c of the upper female lever 62 comes into contact with an engaging portion of a stopper member 82 having a crank shape in a side view which is screwed to the base plate 61.

That is, when the lower knife lever 64 is at the standby position, the upper knife lever 62 is positioned at the standby position shown by the solid line against the spring force of the spring 81 due to the contact between the contact member 80 and the lower knife lever 64. There is. At this time, the engaging portion 62c
A gap of a predetermined amount is provided between and the locking portion of the stopper member 82. Then, as the lower knife lever 64 rotates to the operating position, the upper knife lever 62 also rotates in the clockwise direction at the same time, but when the engaging portion 62c abuts on the locking portion of the stopper member 82, The rotation of the female lever 62 is restricted at the cutting position indicated by the chain double-dashed line. Further, when the lower knife lever 64 returns to the standby position, the upper knife lever 62 is rotated and returned to the standby position in synchronization with the lower knife lever 64 from the time when the lower knife lever 64 and the contact member 80 abut.

As described above, the bobbin thread 5 is moved by the thread cutting device 60.
5 and the needle thread 13 are cut, and when the cut needle thread 13 is thread wiped and held by the thread wiping / holding device 20, as described above, the needle gripping spring 36 is provided in the vicinity of the tip of the thread gripping spring 36. While forming the thread holding portion 36a, the thread holding portion 3
A V-shaped guide portion 36 is provided at the tip portion of the sewing needle 11 side from 6a.
Since the needle thread 13 is formed integrally, the needle thread 13 is relatively thick and has elasticity, and when the thread wiping member 27 wipes the needle thread 13, the end portion 13a of the cut needle thread 13 is cut. When the needle thread end portion 13a droops downward from the hook portion 27a, the direction in which the needle thread end portion 13a hangs downward is restricted to the V-shaped narrow range of the guide portion 36b. And the yarn holding portion 36a cooperate with each other to securely hold the yarn.

The V-shaped guide portion 36 may be formed of a wire member and fixed to the thread gripping spring 36. An air cylinder or various actuators can be used instead of the rotary solenoid 24. In addition, at least the thread wiping and holding device has at least the thread wiping member 27 and the thread gripping spring 3
6 and the driving means for driving the thread wiping member 27 may be used with various modifications. It is needless to say that the present invention can be applied to a thread wiping / holding device for various sewing machines such as a single-needle double chain stitch sewing machine and a zigzag stitch sewing machine.

[Brief description of drawings]

FIG. 1 is a perspective view of a decorative stitch sewing machine provided with a thread wiping and holding device.

FIG. 2 is a partially enlarged front view of an arm section and a sewing machine bed section.

FIG. 3 is a perspective view showing a positional relationship among a needle thread, a thread wiping member, and a thread gripping spring when the thread wiping member moves to a thread catching position.

FIG. 4 is a diagram showing a positional relationship among a needle thread, a thread wiping member, and a thread gripping spring while the thread wiping member is moving to a thread holding position.

FIG. 5 is a diagram when the thread wiping member is moved to a thread holding position.
FIG.

FIG. 6 is a perspective view of a looper drive mechanism.

FIG. 7 is a plan view of a thread cutting device provided in the sewing machine bed.

FIG. 8 is a partial perspective view showing the positional relationship among the looper, the lower knife, and the upper knife when the lower knife moves to the working position.

FIG. 9 is a view corresponding to FIG. 3 according to a conventional technique.

[Explanation of symbols]

 1 Decorative stitch sewing machine 9 Needle bar 11 Sewing needle 13 Needle thread 20 Thread wiping and holding device 24 Rotary solenoid 25 Thread wiping lever 27 Thread wiping member 27a Hook portion 31 Thread wiping link 36 Thread gripping spring 36a Thread holding portion 36b Guide portion 60 Thread cutting Device 61 Base plate 62 Upper knife lever 63 Upper knife 64 Lower knife lever 65 Lower knife 66 Drive link rod 70 Thread trimming drive mechanism 76 Thread trimming solenoid

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsunefumi Ito 15-1 Naedai-cho, Mizuho-ku, Nagoya City Brother Industries, Ltd. (72) Inventor Hiroyasu Iwakoshi 15-1 Naeyo-cho, Mizuho-ku, Nagoya City Brother Industrial Co., Ltd. Company (72) Inventor Kiyoshi Ueda 15-1 Naeshiro-cho, Mizuho-ku, Nagoya City Brother Industries, Ltd.

Claims (1)

[Claims] 1. A needle bar having at least a sewing needle at a lower end thereof, a needle bar drive mechanism for vertically reciprocating the needle bar, and a work cloth for feeding the work cloth in synchronism with the vertical movement of the needle bar. A sewing machine having a cloth feeding mechanism and a thread cutting device that cuts at least the needle thread below the needle plate, and in the needle up stop state after the needle thread is cut by the thread cutting device, There is a hook portion that can be engaged with the needle thread extending to the needle plate, and this hook portion is shaken between the thread catching position near the bottom of the sewing needle in the needle upper stopped state and the thread holding position approximately on the side of the sewing needle. A movable thread moving member, and a thread cleaning member disposed at the thread holding position so as to come into contact with the lower surface of the thread cleaning member.
A thread gripping spring that holds the end of the needle thread cut by the thread cutting device, and a drive unit that drives the thread wiping member between the thread catching position and the thread holding position, and the thread gripping spring Of these, a V-shaped guide portion that guides the needle thread that hangs downward from the hook portion when the thread wiping member moves from the thread catching position to the thread holding position is provided on the tip side portion closer to the needle than the thread holding portion. A thread wiping / holding device for a sewing machine characterized by being provided.