JP2000312792A - Sewing machine and memory medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewing machine capable of preventing the needle and the bobbin thread cutting means from interfering with each other when a user manually rotates the upper shaft, etc., without regard to the timing when the power is off. SOLUTION: In this sewing machine, whether the power is off or not is judged (S3) from time to time while the ordinary sewing process is executed (S1). If the power is off, a presser foot lowering signal is outputted (S5). Accordingly, the presser foot is disposed at the cloth pressing position where a cloth to be sewn is pressed, and a bobbin thread cutting means is disposed in the same condition as in the sewing process. The electricity stored in the capacitor of a smoothing circuit of the power source is used for driving the above process. As a result, the bobbin thread cutting means can be retracted from just below the eye of the needle so that the interference with the needle can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine for forming a seam on a work cloth placed on a needle plate, and more particularly, to cutting a lower thread using an electric actuator after forming the seam. Regarding sewing machines that can be used.

[0002]

2. Description of the Related Art Conventionally, as this kind of sewing machine, a sewing means for forming a seam on a work cloth placed on a needle plate, and a work cloth provided below the needle plate and formed by the sewing means. Lower thread cutting means for cutting the lower thread after the formation of the seam, an electric actuator for driving the lower thread cutting means,
A sewing machine equipped with is considered. In this sewing machine, a stitch is formed on a work cloth placed on a needle plate by a sewing means, and then a lower thread cutting means can be driven by an electric actuator to cut the lower thread. For this reason, the work cloth after the formation of the seam can be easily removed from the needle plate.

[0003]

However, in this type of sewing machine, depending on the timing at which the power is turned off,
The bobbin thread cutting means such as scissors and bobbin thread handling may be kept in a state of being disposed immediately below the needle hole. In this case, when the user turns the pulley or the like to manually rotate the upper shaft in order to confirm the encounter of the sewing needle, there is a possibility that the sewing needle and the lower thread cutting means may interfere with each other. In particular, when the presser foot is moved up and down by the electric actuator, such a situation is relatively likely to occur when the power is turned off with the presser foot raised. In this case, the presser foot is held in an elevated state, or only the presser foot lowers, and the bobbin thread cutting means remains disposed immediately below the needle hole. And in the latter case, the user mistakenly thinks that the bobbin thread cutting means has also retreated from directly below the needle hole from the state of the work clamp,
As described above, there is a high possibility that the sewing needle and the lower thread cutting means may interfere with each other.

[0004] Therefore, the present invention is intended to prevent the user from rotating the upper shaft manually by retracting the lower thread cutting means from immediately below the needle hole regardless of the timing when the power is turned off. An object of the present invention is to provide a sewing machine that can prevent a sewing needle from interfering with a lower thread cutting unit.

[0005]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, the invention according to claim 1 comprises a sewing means for forming a seam on a work cloth placed on a needle plate,
Lower thread cutting means disposed below the needle plate and cutting the lower thread after forming a stitch on the work cloth by the sewing means;
A sewing machine comprising an electric actuator for driving the bobbin thread cutting means, wherein the detecting means detects that a power supply for supplying electric power to the electric actuator has been turned off, An auxiliary power supply that holds a fixed amount of power, and when the detection unit detects that the power supply is turned off, the electric actuator is driven and controlled using the power held by the auxiliary power supply, and at least the needle plate And a control means for retracting the lower thread cutting means from immediately below the provided needle hole.

[0006] The sewing machine of the present invention thus configured is
An auxiliary power supply is provided which holds a predetermined amount of power even after the power supply for supplying power to the electric actuator for driving the lower thread cutting means is turned off. When the detecting means detects that the power supply has been turned off, the control means drives and controls the electric actuator using the power held by the auxiliary power supply, and at least immediately below the needle hole provided in the needle plate. The lower thread cutting means is retracted from. For this reason, even when the user rotates the upper shaft manually, the sewing needle and the lower thread cutting means do not interfere with each other. Therefore, according to the present invention, the bobbin thread cutting means can be retracted from immediately below the needle hole regardless of the timing at which the power is turned off, and thus, when the user manually rotates the upper shaft, etc. Interference between the sewing needle and the lower thread cutting means can be favorably prevented. In addition, the above-mentioned auxiliary power supply, even after the above-mentioned power supply is turned off,
As long as at least a predetermined amount of electric power capable of retracting the lower thread cutting means is held as described above, various types can be applied.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the lower thread cutting means is provided at a predetermined position below the cutting position and not immediately below the needle hole before cutting the lower thread. A lower thread holding means for holding the lower thread is provided.After the lower thread holding means once holds the lower thread, the lower thread is held until sewing by the sewing machine is started regardless of the driving state of the electric actuator. The feature is to keep holding.

The lower thread cutting means of the sewing machine of the present invention includes a lower thread holding means, and the lower thread holding means holds the lower thread at a predetermined position below the cutting position prior to the cutting of the lower thread. . For this reason, in the present invention, the lower thread stretched between the lower thread holding means and the work cloth is cut, and the lower thread can be reliably cut. After the bobbin thread is once held, the bobbin thread holding means keeps holding the bobbin thread until sewing by the sewing machine is started regardless of the driving state of the electric actuator. For this reason, at the time of starting the sewing, the sewing means can capture the lower thread very well, and the stitch can be reliably formed. Further, since the predetermined position where the lower thread holding means holds the lower thread is not immediately below the needle hole, even if the upper shaft is rotated while holding the lower thread, the lower thread holding means and the sewing needle may interfere with each other. do not do. Therefore, the effect of the first aspect of the present invention is maintained despite the provision of the lower thread holding means below the needle plate.

Therefore, according to the present invention, in addition to the effect of the first aspect, the catch of the lower thread at the start of sewing is more reliably performed to form the stitch more reliably, and the lower thread is cut. The effect is obtained that the program can be executed more reliably. The invention according to claim 3 is the invention according to claim 1 or 2
In addition to the configuration described above, further comprising an upper thread cutting means for cutting the upper thread above the work cloth after the formation of the stitch by the sewing means, and wherein the lower thread cutting means is configured to cut the upper thread by the upper thread cutting means. After the cutting, the lower thread including the lower thread including the lower thread is provided, the lower means including a lower thread pulling out an end portion of the cut upper thread together with a lower thread entangled with the upper thread below the work cloth. The cutting means is retracted from immediately below the needle hole.

[0010] The sewing machine of the present invention further comprises an upper thread cutting means and a lower thread handling. The upper thread cutting means cuts the upper thread above the work cloth after the formation of the seam by the sewing means. In addition, lower thread handling, after cutting the upper thread by the upper thread cutting means,
The cut end of the upper thread is pulled out below the work cloth together with the lower thread entangled with the upper thread. For this reason, the end part of the upper thread does not remain on the surface of the work cloth, and the aesthetic appearance of the work cloth can be further ensured. Further, in the present invention, the control means retracts the lower thread cutting means including the lower thread handling from immediately below the needle hole.
Or the effect of the invention described in 2 is maintained.

Therefore, according to the present invention, in addition to the effects of the first and second aspects of the present invention, the upper thread cut by the upper thread cutting means is prevented from remaining on the surface of the work cloth, thereby preventing the work cloth from being cut. This brings about an effect that the aesthetic appearance of the image can be more favorably secured. According to a fourth aspect of the present invention, there is provided a sewing means for forming a seam on a work cloth placed on a needle plate, and a seam provided below the needle plate, wherein the seam is formed on the work cloth by the sewing means. A lower thread cutting means for cutting the lower thread, an electric actuator for driving the lower thread cutting means, and an auxiliary power supply for holding a predetermined amount of power even after a power supply for supplying power to the electric actuator is turned off. A storage medium storing a computer program for controlling the sewing machine provided, wherein a detection process of detecting that the power is turned off, and when the detection process detects that the power is turned off, Controlling the drive of the electric actuator using the power held in the auxiliary power supply, and retreating the lower thread cutting means from immediately below a needle hole provided in at least the needle plate, It is characterized by storing a computer program to be executed.

For this reason, if the sewing machine is controlled using the computer program stored in the storage medium of the present invention, it is detected that the power has been turned off by the detection processing, and at the time of detection, the electric actuator is controlled by the control processing. By controlling the drive, the lower thread cutting means can be retracted at least from immediately below the needle hole. Therefore, if the storage medium of the present invention is applied to the control of the sewing machine, the bobbin thread cutting means is retracted from immediately below the needle hole irrespective of the timing at which the power of the sewing machine is turned off, as in the first aspect of the present invention. Therefore, it is possible to prevent the sewing needle and the lower thread cutting means from interfering with each other when the user manually rotates the upper shaft.

[0013]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an appearance of an overlock sewing machine M to which the present invention is applied. In the buttonhole sewing machine M, a buttonhole seam 100 (see FIG. 13) is formed in the work cloth W (see FIG. 14), and the staggered seams 101 and 102 of the buttonhole seam 100 are cut off. This is a buttonhole sewing machine for a so-called buttonhole that forms the hole 110.

As shown in FIG. 1, an overlock sewing machine M
In the sewing machine table 1, a sewing machine motor 2, a pedal 3 for starting or stopping the sewing machine motor 2, an operation panel 4 for inputting various data for forming a buttonhole 110 and a buttonhole 110 are provided. , And a control device 5 for performing drive control of each unit described later.

The buttonhole sewing machine M has a bed 6, a pillar 7, and an arm 8, and as shown in FIG. 2, a sewing mechanism 10 for forming a buttonhole seam 100 on a work cloth W.
, A feed base 11 for feeding the work cloth W, and a feed base drive mechanism 12 for driving the feed base 11 in the cloth feed direction (see FIG. 3)
And the staggered seam 10 of the hole 100 of the work cloth W
The cutter 13 includes a cutter 13 that cuts between the first and the second 102 to form the button hole 110 and a cutter driving mechanism (not shown) that drives the cutter 13 up and down.

As shown in FIG. 2, the sewing mechanism 10 includes a needle bar 15 provided on the head 8a of the arm portion 8, a sewing needle 16 detachably attached to a lower end of the needle bar 15, and a needle bar. Fifteen
Drive mechanism 1 that reciprocates the needle up and down and swings left and right
7 (see FIG. 5), and a shuttle (not shown) provided on the bed portion 6 and forming a buttonhole seam in cooperation with the sewing needle 16. Then, the sewing mechanism 10 is driven while the work cloth W is being fed by the feed stand 11, so that the buttonhole stitch 100 shown in FIG. 13 can be formed. As shown in FIG. 13, the buttonhole seam 100 has a left zigzag stitch 101 and a right zigzag seam 102, and further has a front bar-tacking seam 103 at a front end thereof and a rear bar-tacking seam at a rear end thereof. 104 respectively. At the time of normal sewing, a part of the front bar-tacking seam 103, the left staggered seam 101, the back bar-tacking seam 104, and the right staggered seam 10
2. The seams are formed in the order of the remaining portions of the front bar-tacking seam 103.

Next, the above-mentioned feed base 11 and feed base driving mechanism 12 will be described. As shown in FIGS. 2 and 3, the feed base 11 is formed in a long plate shape in front and rear, and a front end thereof has:
Slot 1 for exposing a part of needle plate 75 (see FIG. 7)
1a is formed. A pair of left and right guide plates 20 are fitted on the upper surface of the bed portion 6.
The feed base 11 is supported so as to be movable back and forth.

The feed base drive mechanism 12 includes a movable member 21 fixed to the lower surface of the rear end of the feed base 11, a movable member 22 fixedly connected to the movable member 21 by a connecting rod 23 that is long in the front and rear directions, A stepping motor 24 for driving the movable member 22 back and forth by a mechanism described below is provided.

The connecting rod 23 extends through the left ends (far side in FIG. 3) of the movable members 21 and 22.
On both front and rear sides of the sewing machine 1 and 22, guides are supported by the sewing machine frame via a pair of bearings 25 so as to be movable back and forth. In addition, on the right side of the connecting rod 23,
Is fixedly provided, and the right end of the movable member 22 is supported by the rod 26 so as to be movable back and forth via a bearing 22a.

A drive pulley 27 is fixed to the output shaft of the stepping motor 24, and a driven pulley (not shown) is fixedly provided on the sewing machine frame behind the drive pulley 27, and an endless belt 28 is provided on both pulleys. Has been passed over. When the above-described movable member 22 is fixed to a part of the belt 28 and the stepping motor 24 is driven, the feed base 11 is driven back and forth together with the movable members 22 and 21.

Incidentally, the rear end of the presser arm 30 having the cloth presser 31 attached to the front end thereof is connected to the movable member 22 so as to be rotatable around an axis oriented in the left-right direction. The presser bar 31 is driven up and down by a cloth presser driving mechanism 33 (see FIG. 4) described later by engaging a groove 30a formed on the front upper surface of the presser arm 30 with the rolling roller 32.
5 is connected. For this reason, the presser foot 31 moves up and down integrally with the presser bar 35 in the vertical direction, and the groove 3 in the front and rear direction.
It is possible to move within the range of 0a. The above-described cutter driving mechanism is mainly configured by a cutter driving solenoid 39 (see FIG. 11), and the cutter 13 has a cutter holder 41 at a lower end of a cutter mounting shaft 40 which is vertically moved by the cutter driving mechanism. It is attached via 41a.

Next, as shown in FIG. 4, the presser foot driving mechanism 33 includes L-shaped link pieces 43 and 44 that can swing about an axis in the left-right direction at the front and rear of the arm 8 and a presser bar. A vertically extending link member 45, which is pin-connected between the front end L and one end of an L-shaped link piece 43,
A vertically long link member 46 pin-connected between one end of the mold link piece 44 and a link member 65 (see FIG. 6) described later.
And a long link member 47 which is pin-connected between the other ends of the L-shaped link pieces 43 and 44. The link member 46 has a pin 46a projecting therefrom.
Has one end 48 of a cam 48 that swings about a horizontal axis.
a is engaged. The other end 48b of the cam 48 is engaged with a pin 49a which is circularly moved in a vertical plane by a stepping motor 49. The cam 48 converts the rotation of the stepping motor 49 into a vertical movement of the link member 46. can do.

Then, the vertical movement of the link member 46 becomes L
Type link piece 44, link member 47, L-type link piece 43,
It is transmitted to the presser bar 35 via the link members 45 sequentially. For this reason, in the presser foot driving mechanism 33, the presser foot 31
Is moved according to the rotation angle of the stepping motor 49 to an arbitrary height between a presser foot position where the work presser W is held down by the presser foot 31 and a maximum rising position where the presser foot 31 is maximally raised. Can be done.

FIG. 5 is a perspective view showing the structure of the needle bar drive mechanism 17. As shown in FIG. As shown in FIG. 5, in the needle bar drive mechanism 17, the above-described needle bar 15 is supported by a needle bar base 51 provided on the arm portion 8 so as to be swingable so as to be vertically slidable. Further, a needle bar holder 52 is fixed to the needle bar 15 at a predetermined position.

On the other hand, the other end 53b of the needle bar connecting rod 53 whose one end 53a circularly moves along the circle C in the vertical plane is
Is connected to the needle bar holder 52 via the. A guide groove 52a having a rectangular cross section in the left-right direction is formed on the square piece 54 side of the needle bar holder 52, and the square piece 54 is movably engaged in the left-right direction with the guide groove 52a. A corner piece 55 is provided on the other end 53b of the needle bar connecting rod 53 on the side opposite to the side on which the corner piece 54 is provided. By engaging the square piece 55 with the vertical groove 56a of the needle bar connecting rod guide 56, the other end 53b of the needle bar connecting rod 53 is guided so as to be movable only in the vertical direction. Further, a flat needle bar guide 57 is fixed to the side surface of the needle bar base 51. The needle bar guide 57 is formed with an elongated hole 57a extending along the needle bar 15, and a projection 52b projecting from the side surface of the needle bar holder 52 is engaged with the elongated hole 57a. At the lower end of the needle bar base 51, the endless belt 6 is rotated by a stepping motor 61.
The tip of a swing lever 62 that swings by being transmitted via 1 a is connected via a square piece 63.

In the needle bar driving mechanism 17 configured as described above, the force applied to the needle bar connecting rod 53 from the upper shaft 64 rotationally driven by the sewing machine motor 2 is transmitted to the needle bar 15 via the square piece 54. Thus, the needle bar 15 can be moved up and down. Further, the force applied to the swing lever 62 from the stepping motor 61 is applied to the needle bar base 51 via the square top 63.
, Whereby the needle bar 15 can be swung right and left. Then, the needle bar 15 is swung right and left in accordance with the vertical movement of the needle bar 15 and the cloth is fed through the feed base 11, whereby the above-described buttonhole stitches 100 and the like can be formed. .

FIG. 6 is a left side view showing the configuration near the lower end 46b of the link member 46 as viewed from the rear side in FIG. As shown in FIG. 6, the lower end 46b of the link member 46 extends into the bed portion 6, and the lower end 46b is connected to one end 6 of the link member 65 that can swing about a left-right axis 65a.
5b. At the other end of the link member 65, a pin 65c is erected, and the pin 65c is formed in a cam hole 67b of a cam plate 67 swingable about a left-right axis 67a.
Is engaged.

The section of the cam hole 67b from the lower end at an angle α is formed in an arc shape centered on the axis 65a, and the section at the subsequent angle β is formed so that the distance from the axis 65a gradually increases. The upper part is formed in an arc shape centered on the shaft 65a. For this reason, the link member 46 slightly descends from the state where the link member 46 is raised most and the pressure foot 31 is at the pressure foot position (shown by a solid line in FIG. 6), and the link member 65 swings in the section of the angle α. During the movement, the cam plate 67 does not swing at all. Subsequently, when the link member 46 further descends and the link member 65 swings in the section of the angle β, the cam plate 67 gradually swings counterclockwise in FIG. Further, even if the link member 65 further swings beyond the section of the angle β, the cam plate 67 does not swing at all.

The rear end 69a of the link member 69 is pin-connected to the upper end of the cam plate 67. This link member 69
Extends forward in parallel with the surface of the bed portion 6, and its tip 69 b has link members 71, 7 as shown in FIG.
3 is connected to the lower thread cutting mechanism 70. Therefore, the link member 69 moves back and forth only during the period in which the link member 65 swings in the section of the angle β, whereby the driving force of the stepping motor 49 is transmitted to the lower thread cutting mechanism 70 described below. Further, the L-shaped link piece 43 and the link member 45 shown in FIG. 4 are pin-connected via an oval hole (not shown), so that the link member 65 swings in the section of the angle α and the section of the angle β. When the link member 46 is lowered, the presser bar 35 does not rise. Therefore, during this period, the presser foot 31 is held at the presser foot position by the urging force of the press spring (not shown).

FIG. 7 is a bottom view showing the structure of the lower thread cutting mechanism 70. As shown in FIG. 7, the lower thread cutting mechanism 70
Shafts 77a, 78a provided vertically on the lower surface of the needle plate 75,
77 which swings around the shafts 79a and 79a, the lower thread handling 7
8 and a lower thread grip 79. In addition, lower thread handling 7
The lower portion 8 is constituted by a support portion 80 having a pin 80a erected at the tip thereof and a lower thread handling main body 81 having a notch 81a at the tip thereof. The yarn handling main body 81 and the support portion 80 are connected so that the mounting angle can be finely adjusted in the swing direction. Pin 8
0a is engaged with a cam hole 77b provided at the tip of the lever 77, and the lever 77 is pin-connected to the link member 73 described above. For this reason, when the link member 69 swings back and forth as described above, the lever 77 and the lower thread handling 78
Swing about the shafts 77a and 78a. Further, an outer peripheral surface adjacent to the notch 81a at the tip of the lower thread handling body 81 is a cam surface 81b, and the pin 7
The lower thread grip 79 swings clockwise in FIG. 7 when the cam surface 81b contacts the cam surface 9b.

The needle plate 75 has a long and narrow needle hole 75a in the left-right direction (the swinging direction of the needle bar base 51) and the tip of the cutter 13 when the button hole is formed, similarly to the well-known hole sewing machine. A cutter hole 75b is formed. The lower surface of the needle plate 75 is formed with a concave portion 75c that includes the periphery of the needle hole 75a and the cutter hole 75b and that forms a moving space for the scissors 83 described below. The scissors 83
A lower thread fixed blade 85 fixed to the lever 77 and a lower thread movable blade 87 that swings around a pin 85a erected on the lower thread fixed blade 85 are provided. The thread movable blade 87 is held in a pressed state by a clasp 89 and a disc spring (not shown). The front edge (left side in FIG. 7) of the lower thread movable blade 87 has left and right projecting portions 87a,
As described later, the front inner wall surface of the concave portion 75c is a cam surface 75d that abuts on the protruding portions 87a and 87b and swings the lower thread movable blade 87.

Further, a hook 79 is provided at the tip of the lower thread grip 79.
A lower thread gripping spring 91 is fixed to the lower surface of the needle plate 75 so as to be in pressure contact with the lower surface of the lower thread grip 79.
The lower thread gripping spring 91 is configured by a leaf spring having a notch 91a on the front side, and, as described later, grasps the lower thread S (see FIG. 14) in cooperation with the hook 79c.

As shown in the perspective view of FIG. 8A and the top view of FIG. 8B, the upper thread T (see FIG. 14) is cut by the upper thread movable blade 95 in the vicinity of the presser foot 31. The upper thread cutting mechanism 99 is provided. Power is transmitted to the upper thread movable blade 95 from the link member 47 (FIG. 4) through a link mechanism (not shown). As shown in FIG. 8B, the upper thread movable blade 95 is Hole 31a formed in 31
Then, the upper thread T connecting the work cloth W and the sewing needle 16 is cut. The upper thread movable blade 95 is configured such that the link member 65 has the angle α described above.
The operation is ended while moving in the section (FIG. 6), and the upper thread T is cut during this operation.

As will be described later, when the buttonhole sewing machine M forms the buttonhole stitch 100 and the buttonhole sewing machine M is stopped, the stepping motor 49 rotates in a direction to push down the link member 46. Then, in response to this, the link member 65 swings in the section of the angle α in the counterclockwise direction in FIG. 6, and the upper thread T is cut during this. Subsequently, the link member 65 swings in the section of the angle β in the counterclockwise direction in FIG. 6, during which the lower thread S is cut as described below. Then, when the link member 46 is further pushed down and the link member 65 further swings in the counterclockwise direction in FIG. Rises as the link member 46 descends.

Here, the link member 65 swings counterclockwise in the section of the angle β, and accordingly the link member 69
The operation of the bobbin thread cutting mechanism 70 when is retracted will be described.
First, during sewing of the buttonhole stitch 100, the link member 69 is disposed at the most advanced position, and the lower thread cutting mechanism 70
Are disposed at the positions shown in FIG.

The link member 65 swings in the section of the angle β,
As the link member 69 retreats, the lever 77 moves to the position shown in FIG.
Swings clockwise in. Since the cam hole 77b of the lever 77 is configured to push the pin 80a forward at the beginning of the swing, the lower thread handling 7
8 also swings clockwise in FIG. Then, the notch 81a of the lower thread handling main body 81 catches the lower thread S connecting the work cloth W and the shuttle (not shown) through the needle hole 75a, and pulls in the swinging direction. Thereby, as described later, the end Ta of the upper thread T cut by the upper thread cutting mechanism 99 is pulled out below the work cloth W together with the lower thread S entangled with the upper thread T. Further, the lower thread handling 78 causes the lower thread S to be hooked on the hook 79c of the lower thread grip 79.

When the lever 77 further swings, and the lower thread handling 78 further swings accordingly, as shown in FIG. 9A, the cam surface 81b of the lower thread handling body 81 is It contacts the pin 79b. When the bobbin threader 78 further swings, as shown in FIG.
By pushing b backward, the lower thread grip 79 swings clockwise in FIG. The lower thread handling 78 is shown in FIG.
When the pin 80a swings to the position shown in (B), the pin 80a engages with a portion of the cam hole 77b formed in an arc shape centered on the shaft 77a. For this reason, even if the lever 77 swings further, the lower thread handling 78 does not swing. In addition, the surface 81c following the cam surface 81b of the lower thread handling body 81 is formed in an arc shape centering on the shaft 78a. For this reason, after the lower thread gripper 79 swings to the position shown in FIG. 9B, the position of the lower thread gripper 79 does not change even if the lower thread handle 78 further swings. Therefore, even if the mounting angle between the support portion 80 and the bobbin threading body 81 is adjusted by the screw 82 and the amount of threading of the bobbin thread S by the bobbin threading 78 is changed,
The driving amount of the lower thread grip 79 does not change.

When the lower thread gripper 79 swings to the position shown in FIG. 9B, the lower thread gripper 78 shown in FIG.
Are omitted, the hook 79c is disposed at a position where the hook 79c bites a predetermined amount along the upper surface of the notch 91a of the lower thread gripping spring 91. For this reason, the lower thread S is reliably held between the hook 79c and the notch 91a.

At this time, the projection 87b of the lower thread movable blade 87 comes into contact with the cam surface 75d, so that the scissors 8 are formed.
3 begins to close. Then, when the pin 80a reaches the end of the cam hole 77b and the swing of the lever 77 stops (coincident with the time when the link member 65 swings completely in the section of the angle β and the retreat of the link member 69 stops). As shown in FIG. 10B, the tip of the lower thread movable blade 87 and the lower thread fixed blade 85 completely overlap each other, and the lower thread S stretched between the work cloth W and the hook 79c is disengaged with scissors 83. Finishes cutting.

On the other hand, when the sewing of the buttonhole seam 100 is started again by lowering the presser foot 31, the link member 69 is started.
Moves forward, and the lever 77 and the lower thread handler 78 return to the positions shown in FIG. At this time, the protruding portion 87a of the lower thread movable blade 87
Comes into contact with the cam surface 75d, so that the scissors 83 also
It returns to the open state as shown in FIG.

The lower thread grip 79 is operated by a pin 79d projecting rearward via a link mechanism (not shown) when the feed stand 11 starts moving after the sewing operation is actually started. To return to the position shown in FIG. For this reason, the lower thread S is held between the hook 79c and the notch 91a at the start of the next sewing, so that the formation of the seam at the start of the sewing can be performed well. Moreover, the lower thread S is provided between the hook 79c and the notch 91a.
10A, the scissors 83 do not block the path from the needle hole 75a to the hook 79c, and do not apply any force to the lower thread S as shown in FIG. For this reason,
The lower thread S can be held very reliably by the lower thread grip 79 and the lower thread grip spring 91. Therefore, at the start of the next sewing, the lower thread S can be captured extremely well, and the seam can be formed reliably.

Next, the configuration of a control system of the overlock sewing machine M will be described. As shown in FIG. 11, the control device 5 is configured by a microcomputer having a CPU 5a, a ROM 5b, and a RAM 5c as main components, and further receives a signal corresponding to an operation state of the pedal 3, a signal from the operation panel 4, and the like. Drive circuits 501, 502, 503, 50 are connected to the input interface 5d and the sewing machine motor 2, the stepping motor 24, the stepping motor 49, the stepping motor 61, and the cutter driving solenoid 39.
4, and an output interface 5e for outputting a control signal such as a display state also to the operation panel 4 via the bus 5f. Further, the control device 5 is also provided with a power ON / OFF detection unit 507 described later.

The overlock sewing machine M has AC1
A power supply unit 700 that supplies power to the control device 5 from a commercial power supply of 00V is provided. The power supply unit 700 connects / disconnects with the commercial power supply according to the operation of the power switch 701.
Disconnection (hereinafter, also referred to as power ON / OFF) is switched, and a transformer 703 that converts the voltage to a predetermined voltage when connected to a commercial power supply, and a rectifier that rectifies an AC current of the predetermined voltage supplied from the transformer 703. Part 705,
Smoothing section 7 for smoothing the current after rectification by rectification section 705
07. The smoothing unit 707 includes a well-known smoothing circuit centered on a capacitor (not shown) and the like.
A 5 V DC current for driving the PU 5 a and the like and a 55 V DC current for driving the sewing machine motor 2 and the like via the drive circuits 501 to 505 are generated, and the control device 5
Is to be entered. Further, a power ON / OFF detection unit 507 provided in the control device 5 detects whether the power is ON or OFF based on the output of the transformer 703, and inputs the detection result to the input interface 5d.

In the buttonhole sewing machine M configured as described above, after various data such as the width and pitch related to the buttonhole stitch 100 are set on the operation panel 4, the pedal 3
Is depressed, the control device 5 executes the program stored in the ROM 5b, and the work cloth W
0 is formed. Next, the control device 5 (in particular, the CPU 5
The processing executed by a) will be described with reference to the flowchart of FIG.

When the processing is started, the control device 5 firstly
In S1 (S represents a step: the same applies hereinafter), a normal sewing process is executed. That is, in this sewing process, data of a needle drop point which forms the buttonhole stitch 100 is created based on the data input from the operation panel 4, and the sewing machine motor 2 and the stepping motor 2 are formed to form a stitch at the needle drop point. 24 and 61 are driven.

FIG. 13 is an explanatory diagram showing needle drop data used by the buttonhole sewing machine M. This data is data of 113 needle drop points from the needle drop points P1 to P113. In the process of S1, the control device 5 drives the sewing machine motor 2, the stepping motors 24 and 61 based on this data, and the needle drop points P1, P2,.
The seam is formed in the order of. Thus, sewing is performed in the order of a part of the front bar-tacking seam 103, the left staggered seam 101, the back bar-tacking seam 104, the right staggered seam 102, and the remaining part of the front bar-tacking seam 103. The control device 5
The cutter drive solenoid 39 is driven to form the button hole 110 by the cutter 13 at a predetermined time during the sewing of the right zigzag stitch 102 or at the end of the sewing of the right zigzag stitch 102. After the completion of the formation of the buttonhole stitches 100, the control device 5 drives the stepping motor 49 to lower the link member 46, and drives the upper thread cutting mechanism 99 and the lower thread cutting mechanism 70 as described above. , And cloth foot 31
Are sequentially executed.

Returning to FIG. 12, the control device 5
The routine proceeds to S3 at any time during the execution of the normal sewing process by the CPU, and determines whether or not the power has been turned off based on the detection signal from the power ON / OFF detection unit 507. If it has not been turned off (S3: NO), the above-described normal sewing process in S1 is continued, and if it has been turned off (S3: YE
S) shifts to the following S5. In S5, the control device 5 outputs a work clamp lowering signal to the drive circuit 503 and ends the process.

The cloth presser lowering signal is a signal for driving the stepping motor 49 to raise the link member 46 to the highest position. By the output of this signal, the presser foot 31 descends and is disposed at the presser foot position,
By arranging the link member 69 at the most advanced position, each member of the lower thread cutting mechanism 70 is arranged at the position shown in FIG. When the power is turned off, the power supply from the commercial power supply is stopped. However, a predetermined amount of power is still stored in the capacitor and the like of the smoothing unit 707 (at least when the link member 69 is disposed at the most advanced position). A sufficient amount of power) is maintained. Then, when the presser foot lowering signal is output to the driving circuit 503 in S3, the driving circuit
The stepping motor 49 is driven using the electric power held at 07, and the presser foot 31 and the lower thread cutting mechanism 70 are disposed as described above.

For this reason, in the buttonhole sewing machine M, the scissors 83 of the lower thread cutting mechanism 70, the lower thread handling 78 and the like can be retracted from immediately below the needle hole 75a regardless of the power-off timing. (See FIG. 7). For example,
Even if the power is turned off while the presser foot 31 is being raised, the presser foot 31 can be lowered and the lower thread cutting mechanism 70 can be retracted. Therefore, even when the user manually rotates the upper shaft 64 via a not-shown pulley or the like, interference between the sewing needle 16 and the lower thread cutting mechanism 70 can be satisfactorily prevented.

Further, in the buttonhole sewing machine M, as described above, the lower thread S is held by the lower thread grip 79 until the next sewing starts, so that the lower thread S is surely captured at the start of sewing. And the seam can be reliably formed. Moreover, since the position where the lower thread gripper 79 holds the lower thread S is not immediately below the needle hole 75a as shown in FIG. 10A, even if the upper shaft 64 is rotated while the lower thread S is being held, the lower thread The grip 79 does not interfere with the sewing needle 16. Therefore, despite the provision of the lower thread grip 79 below the needle plate 75, the effect of preventing the interference is maintained. Furthermore, in the overlock sewing machine M, the aesthetic appearance of the work cloth W after sewing can be extremely excellently secured as described below.

That is, as shown in FIG. 13, in the data of the needle drop points used in the buttonhole sewing machine M, the penultimate needle drop point P112 is disposed at the left end of the buttonhole stitch 100, and Is located near the needle drop point P113. For this reason, in the buttonhole sewing machine M,
As described below, the length of the end of the lower thread S remaining on the back side of the work cloth W can be reduced.

As described above, in the buttonhole sewing machine M, after the upper thread T is cut by the upper thread cutting mechanism 99, the end Ta of the cut upper thread T is processed together with the lower thread S by the lower thread handler 78. The cloth W is pulled out below. For this reason,
As schematically shown in FIG. 14A, the end Ta protrudes from the needle drop point P113 to the surface of the work cloth W when the upper thread T is cut.
As schematically shown in (B), the end portion Ta is pulled out below the work cloth W together with the lower thread S. Therefore, the needle drop point P11
Finally, no seam is formed at 3 and the last seam is the penultimate needle drop point P112. Then, the scissors 83 cut the lower thread S stretched between the needle drop point P112 and the hook 79c.

In the buttonhole sewing machine M, since the needle drop point P112 is disposed at the left end of the buttonhole stitch 100, the bobbin thread S stretched between the work cloth W and the hook 79c is provided.
And the length of the end of the lower thread S remaining on the back side of the work cloth W after cutting is also reduced. Moreover, the end Ta of the upper thread T does not remain on the surface of the work cloth W as described above. Therefore, in the overlock sewing machine M, the aesthetic appearance of the work cloth W on which the overlock stitches 100 are formed can be secured well. Further, in the hole overlock sewing machine M, the mounting angle of the support portion 80 and the lower thread handling main body 81 can be adjusted by the screw 82, and the amount of the lower thread S to be released by the lower thread separator 78 can be changed. For this reason, the thickness of the work cloth W and the lower thread S
The upper thread T can be satisfactorily applied to the work cloth W even when the thickness of the
, It is possible to secure the beauty of the work cloth W.

In the overlock sewing machine M, as described above, the lower thread S is held by the lower thread grip 79 before cutting the lower thread S by the scissors 83, and the work cloth W and the hook 79 are held.
Since the lower thread S stretched between the lower thread c and the lower thread c is cut, the lower thread S can be reliably cut at a stable position. Further, the lower thread grip 79 does not move during the cutting of the lower thread S, and the holding position of the lower thread S is fixed to a predetermined position near the needle plate 75. Therefore, the above-mentioned holding can be performed reliably, whereby the end of the lower thread S remaining on the back side of the work cloth W can be further shortened, and the aesthetic appearance of the work cloth W can be further ensured. Further, since the holding position is fixed to the sewing start side in the vicinity of the needle plate 75, the lower thread S can be more appropriately captured when sewing is started next time, and the stitch can be formed more reliably. it can.

In the above embodiment, the sewing mechanism 10 serves as a sewing means, the lower thread cutting mechanism 70 serves as a lower thread cutting means, the stepping motor 49 serves as an electric actuator, and the like.
The capacitor of the smoothing unit 707 is used as an auxiliary power
ROM 5b storing processing of OFF detection section 507 and S3
And a ROM storing the processing of the drive circuits 503 and S5 in the detecting means by the CPU 5a executing the processing.
The storage area 5b and the CPU 5a executing the processing correspond to the control means, the lower thread grip 79 corresponds to the lower thread holding means, and the upper thread cutting mechanism 99 corresponds to the upper thread cutting means. Also,
The ROM 5b corresponds to the storage medium described in claim 4. In this case, the processing of S3 corresponds to the detection processing, and the processing of S5 corresponds to the control processing. Furthermore, the present invention is not limited to the above-mentioned embodiment at all, and can be implemented in various forms without departing from the gist of the present invention. For example, an air cylinder or another electric motor may be used as the electric actuator in addition to the stepping motor, and a battery or the like may be used as the auxiliary power supply.

The present invention can be similarly applied to various sewing machines other than the hole sewing machine. Furthermore,
In the above embodiment, the presser foot 31 is connected to the stepping motor 4 which is an electric actuator common to the bobbin thread cutting mechanism 70.
9, the presser foot 31 may be driven by another actuator, or may be manually raised and lowered. However, in a general sewing machine in which the presser foot and the bobbin thread cutting means are driven by a common electric actuator, when the presser foot is lowered, the user mistakenly recognizes that the bobbin thread cutting means is also retracted from immediately below the needle hole. As described above, there is a high possibility that the sewing needle and the lower thread cutting means may interfere with each other. On the other hand, in the above embodiment, the present invention is applied to the hole sewing machine M in which the presser foot 31 and the bobbin thread cutting mechanism 70 are driven by a common electric actuator (stepping motor 49). Therefore, the effect of the present invention is more remarkably exhibited.

Further, as the storage medium according to the fourth aspect, various forms other than elements such as a ROM and a RAM can be considered. For example, a CD-ROM, a floppy disk, or the like, a program cartridge that can be inserted into a card slot, or a file server on the Internet may be used.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a hole sewing machine to which the present invention is applied.

FIG. 2 is a right side view illustrating a main configuration of a sewing mechanism of the sewing machine.

FIG. 3 is a perspective view illustrating a configuration of a feed base driving mechanism of the sewing machine.

FIG. 4 is a right side view illustrating a configuration of a cloth presser driving mechanism of the sewing machine.

FIG. 5 is a perspective view illustrating a configuration of a needle bar driving mechanism of the sewing machine.

FIG. 6 is a left side view illustrating a configuration of a connecting portion between the lower thread cutting mechanism of the sewing machine and the cloth presser driving mechanism.

FIG. 7 is a bottom view showing the configuration of the lower thread cutting mechanism.

FIG. 8 is a perspective view and a top view illustrating a configuration of a needle thread cutting mechanism of the sewing machine.

FIG. 9 is an explanatory diagram illustrating an operation related to a lower thread holding mechanism of the lower thread cutting mechanism.

FIG. 10 is an explanatory diagram showing an operation related to lower thread cutting of the lower thread cutting mechanism.

FIG. 11 is a block diagram illustrating a configuration of a control system of the sewing machine.

FIG. 12 is a flowchart showing a process executed by the control system.

FIG. 13 is an explanatory diagram showing needle drop point data used by the sewing machine.

FIG. 14 is an explanatory view schematically showing an effect of lower thread handling of the sewing machine.

[Explanation of symbols]

2 ... sewing machine motor 3 ... pedal 4 ... operation panel
5 Control device 5a CPU 5b ROM 10 Sewing mechanism 16 Sewing needle 24, 49, 61 Stepping motor 33 Cloth press drive mechanism 45, 46, 47, 65, 69, 71, 73 Link member 67 Cam plate 70: Lower thread cutting mechanism 75: Needle plate 75a: Needle hole 77: Lever 78: Lower thread handling 79: Lower thread grip 82: Screw 83: Scissors 91: Lower thread gripping spring 99: Upper thread cutting mechanism 1
00: Overhole seam 501, 502, 503, 504, 505: Drive circuit 507: Power ON / OFF detection unit 700: Power supply unit
701: Power switch 707: Smooth section M: Overhead sewing machine S
... Bottom thread T ... Top thread W ... Work cloth

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toru Shibata 15-1 Naeshiro-cho, Mizuho-ku, Nagoya, Aichi Prefecture Inside of Brother Industries, Ltd. (72) Inventor Yukio Nishida 15-1 Naeshiro-cho, Mizuho-ku, Nagoya-shi, Aichi No. Within Brother Industries, Ltd. (72) Takashi Kondo, Inventor No. 15-1, Nashiro-cho, Mizuho-ku, Nagoya, Aichi Prefecture Inside of Brother Industries, Ltd. (72) Atsushi Kamano, 151-1 Naeshiro-cho, Mizuho-ku, Nagoya, Aichi Prefecture No. F-term in Brother Industries, Ltd. (reference) 3B150 AA24 CE01 CE05 CE22 FH02 FH03 FH11 FH15 LA00 NA00 NB07 NB16 NC11 QA01 QA02 QA06 QA07

Claims (4)

[Claims] 1. A sewing means for forming a seam on a work cloth placed on a needle plate, and a lower thread provided after the needle plate and forming a seam on the work cloth by the sewing means. A sewing machine comprising: a lower thread cutting means for cutting; and an electric actuator for driving the lower thread cutting means, wherein a power supply for supplying power to the electric actuator is turned off.
Detection means for detecting that the power has been turned off; an auxiliary power supply for holding a predetermined amount of power even after the power supply has been turned off; and holding the auxiliary power supply when the detection means has detected that the power supply has been turned off. And a control means for controlling the drive of the electric actuator by using the supplied electric power and retracting the lower thread cutting means from at least immediately below a needle hole provided in the needle plate. 2. The bobbin thread cutting means further comprises bobbin thread holding means for holding the bobbin thread at a predetermined position below the cutting point and not immediately below the needle hole prior to cutting the bobbin thread. 2. The sewing machine according to claim 1, wherein after the thread holding means once holds the lower thread, the lower thread continues to be held until sewing by the sewing machine is started regardless of the driving state of the electric actuator. 3. An upper thread cutting means for cutting an upper thread above the work cloth after the formation of a stitch by the sewing means, and wherein the lower thread cutting means cuts the upper thread by the upper thread cutting means. A lower thread separating device for pulling out an end of the cut upper thread together with a lower thread entangled with the upper thread below the work cloth; wherein the control means controls the lower thread cutting including the lower thread separating. 3. The sewing machine according to claim 1, wherein the means is retracted from immediately below the needle hole. 4. A sewing means for forming a seam on a work cloth placed on a needle plate, and a lower thread disposed below the needle plate, and forming a seam on the work cloth by the sewing means. A sewing machine comprising: a lower thread cutting means for cutting; an electric actuator for driving the lower thread cutting means; and an auxiliary power supply for holding a predetermined amount of power even after a power supply for supplying power to the electric actuator is turned off. A storage medium storing a computer program for controlling the power supply, comprising: a detection process for detecting that the power supply is turned off; and an auxiliary power supply when the power supply is detected to be off by the detection processing. Controlling the drive of the electric actuator using the electric power held in the needle plate, and retreating the lower thread cutting means from at least immediately below the needle hole provided in the needle plate. Storage medium characterized by storing a computer program for.