CN1381628A - Buttonhole machine controlled by sewing machine - Google Patents

Abstract

A keyhole sewing machine, the keyhole sewing machine (10) comprising: a bottom thread rewinding device ( 80), the cloth feeding platform (13) that moves between the origin position and the sewing position, the fixed cutter (44), the movable cutter (50), the clamping part that clamps the bottom thread when the bottom thread is cut off, and the bottom thread Bottom thread cutting device (37) that can make the clamping part in the state of thread clamping release (64) that can pass through the bottom thread or can release the bottom thread before and after cutting; After the specified action, the lower thread is cut off by the lower thread cutting device while the lower thread is clamped by the clamping part, and then the lower thread rewinding mechanism is returned to the initial state before the lower thread is released by the lower thread release device. This keyhole sewing machine prevents the bobbin thread from falling off when the bobbin thread is cut.

Description

Keyhole Sewing Machine

technical field

The present invention relates to a keyhole sewing machine which, while forming a hole such as a buttonhole, lockstitches the periphery of the hole.

Background technique

In conventional keyhole sewing machines, stitches are formed around the hole through the coordinated action of a needle threaded with an upper thread that moves up and down and swings left and right, and a hook with a lower thread threaded under the needle.

In addition, on this keyhole sewing machine, there is provided the bobbin thread cutting device as disclosed in Japanese Patent Application Laid-Open No. 2000-300885. Shown in FIG. 2 is the bobbin thread cutting device 37 disclosed in the above-mentioned gazette. The bobbin thread cutting device 37 drives the movable cutter 50 to rotate horizontally toward the fixed cutter 44 to cut the bobbin thread 38 and the core thread 34 between them.

The bottom thread cutting device 37 is provided with a clamping mechanism 55. Before cutting, the bottom thread 38 and the core thread 34 are clamped by the clamping mechanism 55, and tension is applied to each thread so as to be easily cut off. At the same time, the thread is still clamped after cutting. , to start the next sewing smoothly. The above-mentioned clamping mechanism 55 has a core thread clamping plate 58 and a bottom thread clamping plate 60 arranged above and below the fixing plate (bottom thread clamping and fixing plate) 56, and the core thread is clamped between the fixing plate 56 and the core thread clamping plate 58. 34. Clamp the bottom thread 38 between the fixing plate 56 and the bottom thread clamping plate 60 .

In addition, a clamp releaser 64 is provided near the movable cutter 50 . Before cutting the suture, if the thread tension releaser 64 and the movable cutter 50 rotate simultaneously, the action part 65 at its front end will press the thread tension pin 62 of the clamping mechanism 55 downward, so that the bottom thread tension plate 60 Just be pressed downward, and make open between the fixed plate 56 and the bottom thread clamping plate 60, the bottom thread 38 is clamped in the middle of it reliably.

And, although it is not listed in the above-mentioned bulletin, the suture thread is actually consumed to some extent during cutting. For this reason, a bottom thread rewinding device that falls the bottom thread and makes it slack is provided below the above-mentioned rotary hook, and the thread rewinding is used to supplement the consumption of the cut thread before cutting the suture. Carrying out thread rewinding in this way, the suture thread is in the state of being pulled to a certain extent when cutting off, and, after cutting thread, tension force is hardly applied to the bottom thread again.

When the suture thread is cut off, the thread is first rewound with the bobbin thread rewinding device before the thread is cut off, and then the movable cutter 50 is fixed to the bottom thread under the state of hooking the core thread 34 with its recess 50a and the bobbin thread 38 with the recess 50b respectively. Cutter 44 rotates, and at this moment, clamping thread releasing device 64 also rotates together, when will cut off, makes clamping mechanism 55 become open state with the action part 65 of clamping thread releasing device 64, and the movable cutter 50 is brought over. The core wire 34 and the bottom wire 38 are respectively clamped. Next, the movable cutter 50 comes into contact with the fixed cutter 44 to cut the core thread 34 and the bobbin thread 38 . Then, the movable cutter 50 and the clamp releaser 64 rotate in opposite directions and return to their original positions.

Due to the reverse rotation of the thread tension release device 64, the action part 65 opens the space between the fixed plate 56 and the bottom thread tension plate 60 through the thread tension pin 62 again. Therefore, as stated in paragraph 25 of the above-mentioned communiqué, the bottom line 38 will not come out.

However, when the lower thread is made of a material that does not slide easily, such as spandex, or when the stock of the lower thread supply source decreases, the load on the lower thread supply source side increases, and the lower thread is rewound from the lower thread supply source. The bottom thread of the path of the device expands and contracts, reducing the actual thread rewinding amount before cutting. In this state, since tension is generated on the cut and clamped bobbin thread, the bobbin thread 38 may fall off once the space between the fixing plate 56 and the bobbin thread clamping plate 60 is released after cutting. .

Once the bobbin thread comes out, the initial stitch skipping and poor thread tightness will occur in the next sewing, which will cause a problem that a good stitch cannot be formed.

At this time, if the bobbin thread rewinding device is used to make the rewinding amount large enough before cutting the suture, the bobbin thread can be prevented from falling off as described above. However, once the amount of thread falling is too large, the bottom thread will be in a loose state. It is difficult to separate the core thread from the bottom thread before cutting. The action of the movable cutter cannot eliminate the loose part during cutting. There is a possibility that it cannot be cut without being tensioned.

An object of the present invention is to provide a keyhole sewing machine capable of reliably cutting the lower thread, preventing the lower thread from falling off during cutting, and forming a good lock stitch.

Contents of the invention

In order to solve the above problems, the keyhole sewing machine of 1 of the present invention, for example, as shown in Fig. 1, Fig. 5 and Fig. 6, has:

Facing the needle bar (11) on the machine head (14) of the sewing machine frame, it is arranged on the base part (12) and the rotary hook device (rotating hook part (20) synchronously acting with the needle bar ) and the rotary hook support portion (70));

Bottom thread rewinding device consisting of a bobbin thread rewinding mechanism (80a) that loosens the bobbin thread by returning it to its original state after reeling out the bobbin thread (38), and a bobbin thread rewinding drive mechanism (needle thread cutting cylinder 92) that drives the bobbin thread rewinding mechanism (80);

A cloth feeding table (13) arranged on the base part, carrying the sewing product (F) and moving at least between the origin position and the sewing position;

The movable cutter (50) for cutting the bottom thread, and the clamping parts (clamping fixing plate 56, core thread clamping plate 58) for clamping the bottom thread from before cutting to after cutting the bottom thread are arranged on the cloth feeding table. , bottom thread clamping plate 60), and a bottom thread cutting device (37) composed of a release part (clamp thread releaser 64) that makes the clamping part in a state of penetrating the bottom thread or releasing the bottom thread before and after cutting the bottom thread;

The keyhole sewing machine (10) performs keyhole sewing with the coordinated action of the needle bar and the rotary hook device, and then cuts the bottom thread with the bottom thread cutting device, and is characterized in that:

When cutting the bobbin thread, the bobbin thread rewinding mechanism is actuated by the bobbin thread rewinding drive mechanism, and then the bobbin thread is cut off by the bobbin thread cutting device while the bobbin thread is clamped by the clamping part, and then the clamping part is released by the releasing part. Before the state of the bobbin thread, the bobbin thread rewinding mechanism is restored to its original state by the bobbin thread rewinding driving mechanism.

According to the keyhole sewing machine of the present invention 1, firstly, the lower thread rewinding mechanism starts the above-mentioned predetermined action from the initial state, and the lower thread is rewound. In this state, the lower thread is clamped by the clamping member, and then the lower thread cutting device Cut off the bottom thread, then make the bottom thread rewinding mechanism return to the original state and make the bottom thread slack, and then make the clamping part be in the state where the bottom thread can be released by the release part. At this moment, since the lower thread is in a slack state, it will not fall off from the holding member.

That is, the bobbin thread is slack until the clamping mechanism is in a released state, so even if the load is heavy due to the type of the bobbin thread or the thread supply side, the bobbin thread will not fall off from the clamping member, and will not fall off in the next pass. Good keyhole stitches can be formed smoothly when stitches, etc., are skipped during sewing.

Moreover, since the lower thread is in the state of being unwound by the lower thread unwinding device before cutting, a certain degree of tension is applied to the lower thread, and the lower thread can be easily cut.

Here, when the bobbin thread rewinding driving mechanism is turned on, the bobbin thread rewinding mechanism will perform the above-mentioned specified action, and when it is turned off, it will return to the initial state to loosen the thread. And when returning to the initial state, the bobbin thread rewinding driving mechanism is turned on and off respectively. In addition, as the bobbin thread rewinding driving mechanism, air cylinders, solenoids, motors, etc. can be used, which can be used as a dedicated driving power for the bobbin thread rewinding device, or as a driving power for other actions.

The keyhole sewing machine of the second aspect of the present invention is in the keyhole sewing machine of the first aspect of the present invention, for example, as shown in Fig. 10 and Fig. 12, and is characterized in that:

The cloth feed table moves from the sewing position to the origin position before the bottom thread is cut after sewing is finished; and there is a selection mechanism (operating panel 150) for selecting whether the bottom thread is rewound by the bottom thread rewinding device and the bottom thread is loosened before the bottom thread is cut. , 200).

If the amount of movement of the cloth feed table from the sewing position to the origin position is long before the bobbin thread is cut, the amount of bobbin thread consumed on the sewing product connected to the cloth feed table will be large. According to the keyhole sewing machine according to the second aspect of the present invention, it is possible to select whether or not to use the lower thread rewinding device to reel out and loosen the lower thread before the lower thread is cut by the selection mechanism. Therefore, when the bobbin thread consumption is large, the bobbin thread rewinding is selected by the selection mechanism, so as to prevent excessive tension on the bobbin thread when the cloth feeding table moves. In addition, when the moving amount is short and the bobbin thread consumption is small, if the selection mechanism chooses not to rewind the bobbin thread, unnecessary bobbin thread rewinding will not be performed to prevent the bobbin thread from being excessively slack.

The keyhole sewing machine according to the third aspect of the present invention is the keyhole sewing machine according to the first aspect of the present invention, characterized in that:

The cloth feeding table moves from the sewing position to the origin position before the bobbin thread is cut after the sewing is finished; according to the moving length from the sewing position to the origin position, it is automatically determined whether the bobbin thread rewinding device will unwind the bobbin thread before the bobbin thread is cut And loosen the bottom line.

According to the keyhole sewing machine according to the third aspect of the present invention, the same effect as that of the second aspect of the present invention can be obtained, and at the same time, since it is determined automatically, it is more convenient.

The keyhole sewing machine according to claim 4 of the present invention is the keyhole sewing machine described in claim 1 of the present invention, for example, as shown in Fig. 10 and Fig. 12, and is characterized in that:

At the beginning of sewing, the cloth feeding table moves from the origin position to the sewing position; and there is an option to choose whether to use the bobbin thread rewinding device to unwind the bobbin thread after the bobbin thread is cut and when the cloth feeding table is moved for the next sewing start And the selection mechanism (operating panel 150, 200) for loosening the bobbin thread.

According to the keyhole sewing machine of the fourth aspect of the present invention, if the movement distance of the cloth feed table from the origin position of the sewing start to the sewing position is long, the bobbin thread clamped by the clamping mechanism of the bobbin thread cutting device on the cloth feed table Also consume much, according to the keyhole sewing machine of 4 of the present invention, can select whether to pour out the bottom thread and make it slack by the bottom thread rewinding device when sewing next time by the selection mechanism. Therefore, when the bobbin thread consumption is large due to the movement at the beginning of the next sewing, the bobbin thread is selected by the selection mechanism to prefetch the bobbin thread, so as to prevent excessive tension on the bobbin thread when the next sewing feed table moves. At the same time, the so-called not applying excessive tension to the bobbin thread is to weaken the clamping force of the clamping member, so it is possible to miniaturize each part constituting the clamping member.

When the moving amount is short and the bobbin thread consumption is small, if the selection mechanism is used to choose not to rewind the bobbin thread, the redundant bobbin thread rewinding will not be performed to prevent the bobbin thread from being excessively loose.

The keyhole sewing machine according to the fifth aspect of the present invention is the keyhole sewing machine according to the first aspect of the present invention, characterized in that:

At the beginning of sewing, the cloth feed table moves from the origin position to the sewing position; according to the moving length from the origin position to the sewing position for the next sewing, it is automatically determined after the bobbin thread is cut and for the next sewing start. When the cloth feeding table is moving, whether the lower thread is poured out by the lower thread rewinding device and the lower thread is loosened.

According to the keyhole sewing machine of the fifth aspect of the present invention, the same effect as that of the fourth aspect of the present invention can be obtained, and at the same time, since it can be determined automatically, its convenience is higher.

In addition, the so-called "according to the moving length" in the third or fifth aspect of the present invention may be determined based on the actual moving length, or may be determined based on the sewing length related to the moving length.

Description of drawings

Fig. 1 is an exemplary view of the keyhole sewing machine of the present invention, (a) is an overall perspective view, and (b) is a partially cutaway side view of a base portion.

Fig. 2 is a perspective view of the bobbin thread cutting device of the keyhole sewing machine of Fig. 1 .

Fig. 3 is a plan view of the lower thread cutting device in Fig. 2 when cutting the lower thread.

Fig. 4 is a top view of the clamping mechanism of the lower thread cutting device in Fig. 2 .

Fig. 5 is a plan view of the hook portion and the hook support portion viewed from the front.

Fig. 6 is a side view of the upper thread cutting device.

Fig. 7 is a block diagram of the control circuit of the keyhole sewing machine in Fig. 1 .

Fig. 8 is a schematic diagram of data content set for keyhole sewing.

Fig. 9 is a schematic diagram for explaining formation of a buttonhole and a buttonhole of a stitch by the keyhole sewing machine of Fig. 1 .

Figure 10 is a schematic diagram of the operation panel.

Fig. 11 is a flow chart of the whole action of buttonhole locking.

Fig. 12(a) is an operation panel for setting the memory switch number, and (b) is a table of memory switch setting contents.

FIG. 13 is a flowchart of setting processing in the memory switch setting mode.

Among the figure: 10—keyhole sewing machine, 11—needle bar, 12—base part, 13—cloth feeding platform, 14—machine head, 18—machine needle, 20, 70—rotating hook portion, rotating hook support portion ( rotary hook device), 37—bottom thread cutting device, 38—bottom thread, 44—fixed cutter, 50—movable cutter, 55—clamping device, 56, 58, 60—fixed plate, core thread clamping plate, bottom thread Thread tension plate (clamping part), 64—thread clamp release device, 65—action part, 80—bottom thread rewinding device, 80a—bottom thread rewinding mechanism, 92—air cylinder (upper thread cutting cylinder), F—sewn product , 110—control circuit, 150, 200—operation panel (selection mechanism).

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The keyhole sewing machine 10 of an example of the present invention shown in FIG. Sewing machine with lockstitch W applied all around. The overlock W is composed of a right overlock w1, a round eye overlock w2, a left overlock w3, and a straight bolt overlock w4.

The keyhole sewing machine 10 is composed of a base part 12 of a substantially rectangular box and a machine head 14 erected on the base base 12, and is placed on a sewing machine table (not shown) through a bottom case 16. The front portion of machine head 14 is provided with the needle bar 11 that lower end is equipped with organic needle 18, and it can move up and down and can swing needle to left and right direction (with the drawing sheet perpendicular aspect of Fig. 1 (b)).

In addition, on the base part 12, facing the needle bar 11, a hook supporting part 70 with the hook part 20 on its upper part is provided, and the needle bar 11 and the hook part 20 are synchronously operated and act in cooperation with both. Form the stitches. In addition, when the radial overlock stitch is sewn on the round eye portion _h1 of the buttonhole H, the needle bar 11 and the hook support portion 70 rotate synchronously. The hook portion 20 and the hook support portion 70 will be described later.

In addition, in the vicinity of the rotary hook 20, there is provided an unillustrated mechanism for leading the core thread 34 (Fig. 2, Fig. 3) drawn out from the thread supply source (not shown) to between the left and right swing positions of the machine needle 18. The core wire guiding mechanism is used to strengthen the stitches by sewing the core wire 34 into the pins.

And, also be equipped with the cloth cutting knife (not shown) that is positioned at the cloth cutting knife (not shown) on the rear side of the rotary hook part 20 and the knife supporting platform 33 (Fig. The cloth cutting device operates at a predetermined time to form buttonholes H on the sewn product F (Fig. 3).

On the upper surface of the base portion 12, a cloth feed table 13 on which the sewn product F is set is provided, and on the cloth feed table 13, presser feet 36 for pressing both sides of the buttonhole of the sewn product F are provided.

The cloth feed table 13 is a flat rectangular box as a whole, driven by the X-axis pulse motor 119 and the Y-axis pulse motor 123 (Fig. 7), and can move to the left and right (X) direction and the front and rear (Y) direction.

With the cloth feeding table 13 positioned at the predetermined origin position, the cloth cutting knife and the knife receiving table 30 are set at the vertically opposite positions of the predetermined buttonhole forming position of the sewing product F placed thereon. . When sewing, form the buttonhole at this location first.

Then, by operating the start switch 134, the cloth feeding table 13 is driven to move from the origin position to the forward sewing start position and the sewing product F on the cloth feeding table 13 is relatively moved to a necessary position directly below the machine needle 18. The lock seam around the buttonhole H starts from the lower end of the right lock seam w1 in Figure 9(a), goes through the round eye lock seam w2 to the left lock seam w3, and finally sews the straight bolt lock seam The order of w4 is sewn. In order to sew in this order, the cloth feed table 13 first moves from the above-mentioned sewing start position in the Y direction, and moves forward until the apex of the buttonhole H (the front end of the round eye h1) reaches the position corresponding to the needle 18. state, and then return backward to the sewing end position which is almost the same as the sewing start position.

The moving distance from the origin position of the cloth feed table 13 to the position of the cloth feed table 13 when the apex of the buttonhole H corresponds to the state of the needle 18 (referred to as the end position) is a constant value, for example, set to 64mm. Therefore, the movement distance to the sewing start (end) position differs depending on the sewing length of the buttonhole H (ml value in FIG.

Once the sewing is finished, the cloth feeding table 13 is controlled to return to the original position from the sewing end position. At the same time, in this embodiment, when the cloth sewing product F is placed, the cloth feeding table 13 is moved to the prescribed cloth releasing position. .

On the keyhole sewing machine 10, the lower thread cutting device exactly the same as that in FIG. 2 is provided. Hereinafter, the bobbin thread cutting device 37 provided in the keyhole sewing machine 10 will be described with reference to FIGS. 2 to 4 .

That is, an attachment auxiliary stand 40 for attaching the fixed cutter is fixed to the cloth feed table 13 , and a fixed cutter installation plate 42 is attached to the left end of the attachment assist stand 40 . A fixed cutter 44 is fixed with screws at the rear end of the fixed cutter mounting plate 42, and its free end stretches out toward the bottom line 38 and the core wire 34 directions. The fixed arm 48 can clamp the bottom thread 38 and the core thread 34 and is pivotally supported on the cloth feeding table 13 by the pivot pin 46 so as to be able to flexibly swing horizontally.

A movable cutter 50 facing the fixed cutter 44 is fixed to the fixed arm 48 with screws, and its free end protrudes toward the bottom thread 38 and the core thread 34 . Two upper and lower recesses 50a, 50b are formed on the free end of the movable cutter 50. When the movable cutter 50 moves toward the fixed cutter 44 due to the swing of the fixed arm 48, the core is caught by the upper recess 50a. The thread 34 hooks the bottom thread 38 through the recess 50b on the lower side, so that the bottom thread 38 and the core thread 34 are reliably separated.

The fixed arm 48 is driven by the bobbin thread cutting cylinder 30 (FIG. 7) located below the cloth feeding table 13, and swings between the standby position shown in FIG. 2 and the cutting position shown in FIG. 3 with the pivot pin 46 as the center.

And, the movable cutter 50 hooks the core thread 34 and the lower thread 38 with the recesses 50a, 50b while the fixed arm 48 is swinging from the standby position to the cutting position, and at the same time, the side surface of the movable cutter 50 (the surface facing the rear) Contact with the free end of the fixed cutter 44 to cut off the bottom thread 38 and the core thread 34.

In addition, a clamping mechanism 55 constituted by a fixing plate (lower thread clamping fixing plate) 56 is provided on the installation auxiliary table 40 . That is, an elongated fixing plate 56 whose longitudinal direction is along the front-rear direction is provided on the attachment auxiliary table 40 .

The core wire clamping plate 58 is fixed with screws on the fixing plate 56, and the core wire 34 between the fixing plates 56 is clamped elastically by it. In addition, the bottom thread clamping plate 60 is fixed with screws below the fixing plates 56, and the bottom thread 38 between the fixing plates 56 is clamped elastically by it.

The lower thread clamping plate 60 is provided with a protruding thread clamping pin 62 that penetrates through the fixing plate 56 and the core thread clamping plate 58 and protrudes upward. The rear end is open relative to the fixed plate 56.

The above fixing plate 56, the core thread clamping plate 58 and the bottom thread clamping plate 60 constitute a clamping part.

Furthermore, the fixed arm 48 is provided with a thread tension releaser (release member) 64 which abuts on and disengages from the thread tension pin 62 of the lower thread tension plate 60 to open and close the lower thread tension plate 60 when the thread is about to be cut. Thread clamp release device 64, its base 66 is on the shaft pin 46 top, and the elongated hole 67,67 of its middle part is supported on the fixed arm 48 with the pivot of fixing screw 68, simultaneously, extends from base 66 to movable cutter 50. The action part 65 extends out in the outward direction.

The height below the action part 65 is set to be lower than the upper end of the thread clamp pin 62 in the closed state of the bottom thread clamp plate 60. When the bottom of the action part 65 contacts the upper end of the thread clamp pin 62, the bottom thread clamps The plate 60 is in the open state (Fig. 4). Due to its opening, the bottom thread 38 can be smoothly inserted between the fixing plate 56 and the bottom thread clamping plate 60. On the contrary, if the bottom thread 38 is released under the clamped state, the bottom thread 38 can be released.

On the side surface opposite to the movable cutter 50 on the action part 65, when the movable cutter 50 is in a position just before reaching the cutting position, a concave portion 65a corresponding to the clamping pin 62 is formed, that is, a concave portion 65a is formed. When the action part 65 presses down the thread clamping pin 62 that opens the lower thread clamping plate 60 and reaches the position corresponding to the concave part 65a due to the movement of the thread clamping release 64, it will be detached from the bottom of the thread clamping release 64 to release the lower thread. The clamping plate 60 is in a closed state. In this way, it is ensured that the lower thread 38 is held between the fixing plate 56 and the lower thread clamping plate 60 before being cut off.

Next, the hook portion 20 and the hook support portion 70 constituting the hook device of the present invention will be described with reference to FIGS. 5 and 6 . The hook support portion 70 is composed of components assembled and integrally formed on the main body 71 , that is, an annular portion 71a, a mounting plate 71b, a support frame 71c, and a shaft portion 71d.

A support portion 12a with a circular hole is provided on the base portion 12, and the ring portion 71a is flexibly rotatably embedded in the circular hole and supports the rotary hook support portion 70 flexibly. There is a mounting plate 71b, and a support frame 71c in the shape of a substantially rectangular frame whose length is up and down is provided at the lower portion of the annular portion 71a. 71 d of shaft parts are provided in the lower part of the support frame 71c. A pulley or the like is attached to the shaft portion 71d, and a timing belt (not shown) that rotates the hook support portion 70 and the needle bar 25 around a vertical axis in synchronization is hung on the pulley. The hook support portion 70 and the hook portion 20 can be rotated 180 degrees from the initial rotation position of 0 degrees during sewing.

The hook portion 20 is provided on the mounting plate 71b. The rotary hook portion 20 has rotary hooks 26, 26, diverting hooks 27, 27 assisting the rotary hooks 26, 26, a tongue portion 22 with a needle hole, an upper thread cutter 28, and the like.

Inside the support frame 71c, a rotary hook/splitter hook drive mechanism including the rotary hook drive shaft 23, the shuttle hook drive shaft 24, and the like is provided. That is, the tubular hook drive shaft 23 is arranged along the rotation center of the hook support portion 70 , and the tubular diverter hook drive shaft 24 is arranged inside the hook drive shaft 23 . In addition, the shuttle drive shaft 24 protrudes upward from the rotary hook drive shaft 23 .

In addition, in the shuttle drive shaft 24, the bottom thread 38 (indicated by a thick dotted line) passing from the lower end of the shuttle drive shaft 24 to the needle hole of the tongue part 22 from a suture supply source not shown is threaded. ). In addition, the lower parts of the rotary hook driving shaft 23 and the diverting hook driving shaft 24 protrude below the rotary hook support part 70 through the shaft part 71d, and are connected to the lower shaft not shown through a transmission mechanism not shown.

The rotary hook drive shaft 23 is connected to the lower part of the rotary hook drive shaft 23b through the rotary hook drive shaft guide seat 23a. The upper end portion of the hook driving rod 23b is connected to the hook mounting base 23e, and the hooks 26, 26 are attached to the hook mounting base 23c. In this way, the up and down motion of the rotary hook drive shaft 23 is converted into a prescribed reciprocating rocking motion and transmitted to the rotary hooks 26,26.

The upper end of the shuttle drive shaft 24 is connected to the lower end of the shuttle drive rod 24b through the shuttle drive shaft guide seat 24a. The upper end of the shuttle driving rod 24b is connected with the shuttle action cam 24c that makes the shuttle 27, 27 move, so that the up and down movement of the shuttle drive shaft 24 is converted into a prescribed reciprocating swinging motion and transmitted to the shuttle 27, 27.

In addition, in the support frame 71c, there are provided the lower thread path portion 76 for guiding the lower thread 38 from the upper end of the shuttle drive shaft 24 to the needle hole side of the tongue portion 22, and the lower thread rewinding portion provided in the middle of the lower thread path portion for retrieving the lower thread 38. device 80.

The lower thread path portion 76 is composed of a frame portion 76a installed on the front side of the support frame 71c, each component mounted on the frame portion 76a, a lower thread drawing spring 76b that is a torsion spring, an adjusting disc-type thread adjuster 76c, and a first thread regulator 76c. The thread hooking portion 76d, the second thread hooking portion 76e, and the like are configured.

The coil part of the bobbin thread withdrawal spring 76b is rotatably supported on the frame part 76a, one end of which is fixed on the frame part 76a, and the other end protrudes upwards, and its force is limited by a limiting part 76g on the way. Direction (Figure 5 right) moves, and its front end forms a ring.

The bottom thread 38 is extracted from the upper end of the shuttle drive shaft 24, hung on the outer part of the first thread hanging part 76d and towards the lower side, and then the bottom thread 38 is straddled on the outer part of the second thread hanging part 76e, and wound on Between the two adjustment discs constituting the thread adjuster 76c, the lower thread 38 is then hung on the inner side of the second thread-hanging portion 76e, and then hung on the inner side of the first thread-hanging portion 76d. Then, the bottom thread 38 passes through the ring portion of the bottom thread drawing spring 76b, then passes through the threading pipe 76f mounted on the ring portion 71a to lead to the upper direction of the rotary hook support portion 70, and passes through the rotary hook 26 through the tongue portion 22. The pinhole continues to lead to the sewn object on the needle plate 19.

Simultaneously, thread adjuster 76c applies tension to bottom thread 38 under closed state, and just decontrols bottom thread 38 when the floating piece 74b of the floating plate 74 that is fixed on the bottom thread reversing plate 84 described later is inserted between the regulator discs.

The lower thread rewinding device 80 is composed of a lower thread reeling mechanism 80a composed of a lower thread reeling plate 84, an operating lever 85, etc., and an air cylinder 92 (described later) for cutting the upper thread as a lower thread reeling driving mechanism. Since the bobbin thread rewinding device 80 is used to loosen the bobbin thread 38 before sewing when the bobbin thread 38 is consumed, the bobbin thread 38 is loosened before the bobbin thread 38 is consumed during the movement of the cloth feeding table 13 and the bobbin thread cutting operation. The time for rewinding will be discussed later.

Bottom thread rewinding plate 84 is made up of base portion 84a, extension portion 84c protruding above base portion 84a, and bottom thread rewinding portion 84b on which bottom thread 38 is hung.

The base part 84a is combined with the rotating shaft 86 which rotatably carries it through the bearing part (not shown) at the lower end of the supporting frame 71c, and they can rotate flexibly together. And, on base part 84a, be provided with arc-shaped long hole 84e, be combined with the action lever 85 that passes through rotating shaft 86 by the set screw 87 on this long hole 84e, action lever 85 is fixed on the base 84a. . That is, the bobbin thread reeling plate 84 and the operating lever 85 take the rotating shaft 86 as the axis, and rotate integrally with the rotating shaft 86 in the drawing plane parallel to FIG. 5 .

The front-end|tip part 85a of the operating lever 85 protrudes outward, and is located outside the rotation track of the hook support part 70. As shown in FIG.

On the operating lever 85, one end is hung on the other end of the return spring 81 (bottom thread rewinding spring) on the upper thread cutting action arm 28a. Back-moving spring 81 applies the reset pulling force in the counterclockwise direction in FIG. 5 to bottom thread reeling plate 84 and action lever 85 .

In addition, an elongated hole 84d is formed in the bobbin thread unwinding portion 84b, through which the bobbin thread 38 tensioned by the bobbin thread drawing spring 76b is passed between the first thread hanging portion 76d and the threading tube 76f.

The floating plate 74 of the pressure plate is composed of a base 76a that is relatively rotatably installed on the above-mentioned rotating shaft 86 and fixed on the base portion 84a of the bottom thread reeling plate 84 through the elongated hole 74c, and the pressure line extending from the base 74a. The disk floating piece 74b constitutes. The pressure plate floating piece 76b is arranged at a position where the front end thereof is located directly below the wire adjuster 76c.

And, when the lower thread rewinding plate 84 overcomes the pulling force of the return spring 81 and rotates clockwise, the floating plate 74b of the pressure plate moves upward, and the floating plate 74b of the pressure plate is inserted into the two disks of the clamping bottom thread 38 of the thread adjuster 76c. between. This releases the tension on the lower thread 38 .

From the initial state of FIG. 5, when the front end 85a of the operating lever 85 is pressed down by the drive transmission part 99 described later, the bobbin thread reeling plate 84 and the operating lever 85 rotate clockwise simultaneously. Therefore, the lower thread 38 hung on the elongated hole 84d of the lower thread falling portion 84b is stretched to the right. At this time, as described above, the tension of the thread adjuster 76c is released, so the lower thread can be pulled out from the thread supply source. In this state, once the downward pressure on the front end portion 85a of the action lever 85 is removed, the return spring 81 returns the bottom thread rewinding plate 84 and the action lever 85 to their original state, and the bottom thread 38 is relaxed.

Next, the upper thread cutting device 90 will be described. The noodle thread cutting device 90 is a noodle thread cutting drive composed of the noodle thread cutter 28 provided on the rotary hook 20, the noodle thread cutting arm 28a, etc., and the components assembled in the machine base 12 in the front-rear direction. Mechanism 91 constitutes.

As shown in FIG. 5, the upper thread cutting arm 28a is rotatably mounted on the mounting plate 71b, and the upper portion of the upper thread cutting arm 28a is provided with the upper thread cutter 28. In addition, a part of the upper thread cutting device 90 is omitted in FIG. 5 . In FIG. 6, the hook support part 70 etc. are simplified, and the base part 12 is shown by the dashed-two dotted line.

On the upper thread cutting operation arm 28a, one end of the lower thread rewinding return spring 81 is hung, and the return spring 81 applies a clockwise rotation force so that the upper thread cutter 28 is located at the predetermined cutting standby position.

A convex portion 28c is provided on the upper thread cutting arm 28a, and the upper thread cutting driving mechanism 91 presses down on the convex portion 28c so that the upper thread cutting arm 28a turns counterclockwise, so that the upper thread cutter 28 cuts the upper thread. cut action.

The needle thread cutting drive mechanism 91 is composed of a cylinder for cutting the needle thread (needle thread cutting cylinder) 92, a needle thread cutting link 93, a needle thread cutting drive shaft 94, a thread pressing unit 95, and the like.

The base end side of the air cylinder 92 is rotatably supported by an air cylinder bracket 96 fixed to the machine base 12 with a set screw 96a. In addition, the air cylinder 92 can advance and retreat the cylinder rod 92a mounted on its front portion, and the stretching amount of the cylinder rod 92a is usually a fixed value.

The front end of the cylinder rod 92a is connected to one end of a rotatable substantially T-shaped upper thread cutting link 93 via a cylinder toggle 97 . The middle portion of the upper thread cutting link 93 is rotatably supported on the machine base 12 via the rotating shaft 93a. In addition, a shaft abutment 94a passing through the driving shaft 94 is fixed on the upper and lower upper thread cutting drive shaft 94, and the other end of the upper thread cutting link 93 is rotatably connected to the shaft abutment 94a. The shaft brackets are connected so that the upper thread cutting link 93 supports the upper thread cutting drive shaft 94 from the inside in FIG. 6 . A thread pressing portion 95 is provided at an upper end portion of the upper thread cutting drive shaft 94 . Also, the thread crimping portion 95 is provided so that the thread crimping portion 95 overlaps with the convex portion 28e of the upper thread cutter 28 when the hook support portion 70 is positioned at a rotation angle of 180 degrees.

On the lower part of the upper thread cutting drive shaft 94, the shaft fixing member 98 inserted into the upper thread cutting driving shaft 94 is fixed with screws 98a, 98a, and the upper thread cutting driving shaft 94, which is a plate-shaped member relative to the shaft fixing member 98, is fixed. The drive transmission part 99 passing therethrough.

According to the noodle thread cutting driving mechanism 91 , the driving force of the air cylinder 92 causes the thread pressing portion 95 to move simultaneously with the vertical movement of the noodle thread cutting driving shaft 94 .

That is, as shown in FIG. 6, when the air cylinder 92 is in the OFF state, the cylinder rod 92a is pushed out, and the crimping portion 95 is in the state of stopping at the top dead center. In addition, when the air cylinder 92 is turned on (On), the cylinder rod 92a retracts, and the counterclockwise rotation of the upper thread cutting link 93 moves the thread pressing portion 95 downward until it reaches the bottom dead center state. At this time, if the hook support portion 70 is at the 180-degree rotation position, the thread pressing portion 95 presses the above-mentioned convex portion 28c downward, and the upper thread cutter 28 located at the cutting standby position operates to cut the upper thread. Then, the air cylinder 92 becomes the cut-off state, and the thread pressing portion 95 moves upward to the dead point, and the upper thread cutter 28 is returned to the cutting standby position by means of the pulling force of the above-mentioned return spring of the upper thread cutter 28 at the same time.

The drive transmission portion 99 is a plate-shaped member, and is mounted above the front end portion 85 a of the operating lever 85 substantially perpendicular to the rotation axis of the hook support portion 70 . In addition, there is a constant interval relative to each other in the vertical direction between the lower surface of the drive transmission portion 99 and the front end portion 85 a of the operating lever 85 .

The drive transmission part 99 is slightly crescent-shaped (slightly C-shaped) around the rotating shaft of the rotary hook support part 70 as seen from the up and down direction, and surrounds the rotary hook support part 70 with its inner arc-shaped edge. And, the center where the inner edge forms an arc substantially coincides with the rotation center of the hook support portion 70 . Simultaneously, along with the rotation of the hook supporting part 70, the rotation locus of the front end part 85a of the operating lever 85 moves along the circular arc of the outside of the inside edge part of the drive transmission part 99 and the inside of the outside edge part.

The rotary hook supporting portion 70 is located at a rotation position of approximately 0 degrees at the start of sewing, and reaches almost 180 degrees at the end of sewing. During this period, the tip end portion 85a of the operating lever 85 and the drive transmission portion 99 are always vertically overlapped.

And when the upper thread cutting drive shaft 94 moves up and down, the drive transmission part 99 also moves up and down together and makes contact with the front end portion 85a of the operating lever 85, and moves away from it. If the drive transmission part 99 moves downward when the cylinder 92 is on If it moves, it will definitely press the front end portion 85a. That is, irrespective of the rotation angle of the hook support portion 70, when the drive transmission portion 99 moves downward, it always presses the front end portion 85a of the operating lever 85. If the front end portion 85a is pressed downward, the above-mentioned bobbin thread rewinding operation can be performed. That is, the air cylinder 92 also serves as the bobbin thread rewinding driving mechanism in the present invention.

FIG. 7 is a schematic diagram of the control circuit 110 of the sewing machine 10. As shown in FIG. The control circuit 110 is composed of a CPU 11 , a ROM 112 , a RAM 113 , interfaces 114 , 115 . . . , various drive circuits, an operation panel 150 , a start button 134 , and the like.

A control program and control data for keyhole sewing are written in a ROM (read only memory) 112 .

RAM (Random Access Memory) 113 stores a plurality of graphic data (keyhole control data), and can store a graphic data selected by the operation panel 150 at the same time, in addition, it can also store the data item value when changing the graphic data. changed value. In addition, RAM 113 also has a function of providing a storage space temporarily used for various processes during sewing. In addition, stitch data (described later) generated from pattern data can also be stored.

CPU (Central Processing Unit) 111 controls a series of processes related to the buttonhole according to the control program and control data of ROM 112 .

CPU 111 is connected to operation panel 150 through interface 114 , controls the display on operation panel 150 , receives signals input through operation panel 150 , and performs selection and change of various settings. The operator selects graphic data as shown in FIG. 8 through the operation panel 150, and can change the number of each data item of the selected graphic data. Operation panel 150 will be described later.

Furthermore, the CPU 111 is connected to a spindle servo motor drive circuit 116 through an interface 115 to control and drive the rotation of the spindle servo motor 117 . The spindle servo motor 117 drives an upper shaft (not shown) for moving the needle 18 up and down and a lower shaft (not shown) for actuating the rotary hook and diverting hook drive mechanism.

In addition, the CPU 111 is connected to the X-axis pulse motor drive circuit 120 through the interface 118, and is connected to the Y-axis pulse motor drive circuit 122 through the interface 121 at the same time, drives and controls the X-axis pulse motor 119 and the Y-axis pulse motor 123, and turns the cloth feeding table 13 to drive in the specified direction.

The CPU 111 is connected to the Z-axis pulse motor drive circuit 125 through the interface 124 to control and drive the Z-axis pulse motor 126 .

On the keyhole sewing machine 10, the rotation of the main shaft servo motor 117 is transmitted to the needle bar 18 and the rotary hook and the diverter hook driving mechanism, so that the rotary hooks 26, 26, the diverter hooks 27, 27 and the needle bar 11 move up and down and the machine The stitches move synchronously to form stitches on the sewing product F placed on the cloth feeding platform 13 .

In addition, the needle bar 11 and the hook support portion 70 are connected to a rotating mechanism including a Z-axis pulse motor 126, a timing belt 31, a transmission shaft 32 (FIG. 1(b)) and the like. When the periphery of the round eye overlock portion w2 is radially overlocked, the rotating mechanism drives the needle 18 and the hook portion 20 to rotate synchronously.

The CPU 111 is connected with the bottom thread cutting cylinder driving circuit 128 through the interface 127 to control and drive the bottom thread cutting cylinder 30 . And, it is connected with the upper thread cutting cylinder driving circuit 130 through the interface 129, drives the upper thread cutting cylinder 92, and performs the upper thread cutting and bobbin thread rewinding operations as described above.

The CPU 111 is connected to the cloth cutting motor drive circuit 132 through the interface 131 to control and drive the cloth cutting motor 133 .

Furthermore, the CPU 111 is connected to the start switch 134 through the interface 114, and when a start signal is input from the start switch 134, it drives the spindle servo motor 117 and the like at a predetermined timing to perform keyhole trimming, cloth cutting processing, and upper and lower thread cutting processing.

Data stored in RAM 113 will be described with reference to FIGS. 8 and 9 . Fig. 8(a) is a table t1 showing graphic data when buttonholes are performed. 9 types of graphic data can be stored here, and one graphic data has data items from 1 to 9.

Data item 1 is used to set the shape of the round eye portion h1. As shown in Figure 9(b), the size of the round eye portion h1 is specified as width ew and length el, and the combination of ew and el is stored as a prefabricated table t2 shown in Figure (8). In data item 1, select a number from No.1 to No.5 in table t2 and set it.

Data items 2 to 6 in FIG. 8( a ) are data related to the number of stitches and the length of each portion constituting the buttonhole lockstitch shown in FIG. 9( a ). That is, data item 2 is the total length of the buttonhole (ml), data item 3 is the number of stitches on both sides of the parallel portion h2 (ln), data item 4 is the number of stitches around the round eye portion h1 (en), and data item 5 is the knife-edge clearance of the parallel portion h2 (ls in FIG. 9 ), and data item 6 is the knife-edge clearance of the round eye portion h1 (es in FIG. 9 ).

Data item 7 relates to the size of the straight bolt seam w4. The size of the straight bolt seam w4 is specified by the width cl and the longitudinal length ew, and the combination of cl and ew is stored as the prefabricated table t3 shown in FIG. 8(c). In the data item 7, numbers of No.1 to No.n are selected from the table t3.

Data item 8 is an item for setting whether or not to perform the second bobbin thread rewinding shown in FIG. 11 described later. In addition, data item 9 is an item for setting whether or not to perform the fourth bobbin thread rewinding. Relevant content will be described later.

In the keyhole sewing machine 10, the operation panel 150 can be used to read and set the size and shape of the keyhole to be formed.

The operation panel 150 as the selection mechanism of the present invention is composed of a ready key 151, a graphic number selection part 152, a data item selection part 153, a data value setting part 154 and a data setting switch 155 as shown in FIG.

The pattern number selection unit 152 is provided for selecting a pattern number, and displays the currently selected pattern number (“1” in FIG. 10 ) on the pattern display unit 152 a. The + key 152b and - key 152c below the graphic display part 152a can be used to change the numbers one by one in the range of 1 to 9 to select different graphic data.

The data item selection unit 153 is a selection unit for selecting a data item in the graphic data selected by the graphic number selection unit 152 . The currently selected data item ("1" in FIG. 10) is displayed on the item display portion 153a. Different data items can be selected by sequentially changing numbers within the range of 1 to 9 with the + key 153b and - key 153c below the item display portion 153a.

Once a data item is selected on the data item selection section 153 , a preset number related to the data item is displayed on the numerical value display section 154 a of the data value setting section 154 . The number on the numerical display portion 154a can be changed by increasing or decreasing the number on the numerical display portion 154a at predetermined intervals within a predetermined range by using the + key 154b and the − key 154c under the numerical value display portion 154a.

The data setting switch 155 is an operation switch for performing a data setting operation. That is, when the data setting switch 155 is pressed, the data value can be changed. In addition, pressing the data setting switch 155 again determines the selection and change of each item and number.

The ready key 151 is a switch for creating stitch data corresponding to the set data value after the setting operation is completed.

Next, the operation of the keyhole sewing machine 10 having the above-mentioned configuration will be described based on the flowchart of FIG. 11 .

This general flow starts, for example, when the main power supply (not shown) of the sewing machine is turned on. And, the sewn product F has been placed on the prescribed cloth placing position.

First, it is judged in step S1 whether or not the ready key 151 has been operated. If it has not been operated, this judgment is repeated, and if it has been operated, stitch data will be created in step S2. The creation of the stitch data is based on the data content of the selected pattern data for driving the drive source such as the main shaft servo motor 117, and includes needle entry data for determining the needle entry position of the needle 18 and the like.

Next, in step S3, the cloth feeding table 13 is moved from the cloth placing position to the origin position.

Then, in step S4, it is monitored whether the starter switch 134 is in the ON state, and if it is in the ON state, the process proceeds to step S5. In step S5, the cloth cutting motor 133 drives the knife holder 33 to form the buttonhole H, and in step S6, the cloth feed table 13 is moved to the sewing start position.

Then, in step S7, drive the main shaft servo motor 117, the X-axis pulse motor 119, the Y-axis pulse motor 123, and the Z-axis pulse motor 126 according to the above-mentioned stitch data to carry out buttonhole sewing, and end the keyhole in step S8. At this time, the cloth feed base 13 is at the sewing end position which is substantially the same as the sewing start position.

At the end of the keyhole, the air cylinder 92 is in the off state, the hook support portion 70 rotates 180 degrees from the original position, and the crimping portion 95 overlaps with the convex portion 28c of the upper thread cutter 28 in the vertical direction.

Then, in step S9, the air cylinder 92 is turned on, and the upper thread cutting link 93 and the upper thread cutting drive shaft 94 are used to make the pressing portion 95 press the convex portion 28c downward, and the upper thread cutting knife 28 cuts the noodle. Line cut. Simultaneously, as mentioned above, the driving force of the cylinder 92 presses the actuating lever 85 to rotate the lower thread reeling plate 84 . In this way, the disk floating plate 74 moves upwards, and the disk floating piece 74b is inserted between the two disks of the thread adjuster 76c, and the tension applied to the bottom thread 38 is released, and the bottom thread of the thread plate 84 is rewound by the bottom thread. The thread unwinding portion 84b unwinds the lower thread 38 from the winding side (first thread unwinding).

Then, after the bottom thread 38 has been poured, the cylinder is in a cut-off state, and the upper thread cutter 28 is returned to the cut-off standby position by means of the pulling force of the back-moving spring 81. The tension bottom thread rewinding device 80 returns to the initial state.

Next, in step S10, the cloth feed table 13 starts moving back to the origin position from the sewing end position. The movement of the cloth feed table 13 requires a period of time just before the bobbin thread cutting operation in step S15 described later.

Then, in step S11, the hook support portion 70 at the 180-degree turning position is turned back 45 degrees toward the origin. In this way, in order to cut the lower thread, the lower thread 38 and the core thread 34 are separated by the stepped portion (not shown) of the needle plate 19 .

Next, in step S12, according to the setting of data item 8 in the table t1, it is judged whether or not to perform the second bobbin thread rewinding operation before the bobbin thread is cut.

The data item 8 can be set for the following reasons. As described above, the amount of movement of the cloth feed table 13 from the origin position to the sewing end position varies depending on the length of the buttonhole H (the above-mentioned ml value), and the longer it is, the shorter it is, and the shorter it is, it is longer. Therefore, the return movement to the original position of the cloth feed table 13 from step S10 varies with the length of the buttonhole H (the above-mentioned ml value). In addition, when the cloth feed table 13 moves, the sewing product F fixed on the presser foot 36 moves, and the bobbin thread 38 is also tightened. But, since the bottom thread 38 is poured out in step S9, so when the moving amount of the cloth feeding table 13 is not too long, even if the sewing product F connected with the bottom thread 38 moves, the bottom thread 38 will not be pulled by the cloth. Moreover, if the movement amount is short, the consumption of the bottom thread 38 will also be provided when the bottom thread is cut in step S15, and the bottom thread 38 will not be pulled to the cloth side after being cut.

However, when the amount of movement of the cloth feed table 13 is large, that is, in the lock seam in step S7, when the above-mentioned ml value is short, the amount of movement of the cloth feed table 13 from step S10 becomes long, and the reverse of step S9 The amount of thread is not enough. At this time, when the sewing length is short, the operator sets the bobbin thread rewinding of the data item 8 to "Yes". Then, in step S12, if the data item 8 is "have", just in step S13, under the situation that cylinder 92 is connected, the bottom thread 38 is poured out with the bottom thread rewinding device 80, then loosen and move to Step S14. Bottom thread 38 is poured out in step S13 like this, just can correspond to the consumption when the cloth feeding table 13 moves and the bottom thread of next procedure cuts off.

When the amount of movement of the cloth feeding table 13 is not so much and the data item 8 is set to "none", it does not move from step S12 to step S13, that is, it directly moves to step S14 without bobbin thread rewinding operation.

In step S14, the air cylinder 92 is switched on, and the bottom thread unwinding plate 84 is driven to rotate clockwise in FIG. 5, so that the bottom thread 38 is rewound and tightened. In this tense state, the process proceeds to step S15.

In step S15, on the lower thread cutting device 37 in the waiting state of FIG. Turn counterclockwise. As soon as the movable cutter 50 gets close to the fixed cutter 44, the action part 65 of the clamp release device 64 that rotates simultaneously with the movable cutter 50 presses the clamp pin 62 downward, so that the core wires are respectively clamped by the clamping mechanism 55. 34 and bottom line clamping. Immediately after clamping, the movable cutter 50 contacts the fixed cutter 44 to cut off the core wire 34 and the bottom thread 38 .

Next, in step S16, air cylinder 92 is disconnected, and the bottom thread rewinding plate 84 of tension bottom thread 38 returns to standby state this moment, in order to loosen bottom thread 38 (the 3rd time). Thereafter, in step S17, the lower thread cutting cylinder 30 is turned off, and the movable cutter 50 and the thread clamp releaser 64 rotate clockwise and return to their original positions. At this time, the action part 65 presses down the clamping pin 62 again so that the clamping mechanism 55 (clamping part) is in a state where the bottom thread 38 can be released for a moment. Since the bottom thread 38 is in a loose state, it will not fall off from the clamping mechanism 55. .

Then, in step S18, the presser foot 36 that presses the sewing product F on the cloth feed table 13 is lifted, and the rotary hook support portion 70 is reversed by 135 degrees to make the rotation angle return to 0 degrees.

Then, in step S19, the cloth feeding table 13 is moved to the cloth setting position for the next sewing. Now the bottom thread 38 is clamped by the clamping mechanism 55 fixed on the cloth feed table 13, and then moves simultaneously with the cloth feed table 13. The center is loose, so the bottom line 38 will not be subject to excessive tension and disengage from the clamping mechanism 55.

Next, in step S20, it is judged whether or not to perform the fourth bobbin thread rewinding according to the setting content of the above-mentioned data item 9. If the data item 9 is "Yes", the process proceeds to step S21, where the cylinder 92 is driven to perform the bobbin thread rewinding operation, and the process ends. If it is judged in step S20 that the data item 9 is set to "none", the processing is ended as it is.

This data item 9 is an item for setting whether or not to perform thread rewinding in consideration of the movement amount of the cloth feed table 13 at the time of next sewing. That is, when sewing starts, it moves from the cloth setting position to the origin position, and then moves from the origin position to the sewing start position (steps S3 and S6 in FIG. 11 ). Although the amount of movement from the cloth setting position to the origin position is basically constant, the movement from the origin position to the sewing start position is changed by the sewing length (ml value) described in data item 8, and clamped at The degree of tension suffered by the bottom thread 38 on the clamping mechanism 55 on the cloth feeding platform 13 also changes. Here, the operator considers the next process, if the sewing length is short and the movement is long, set "Yes" on the data item 9, on the contrary, if the sewing length is long and the movement is short, then in step S16 When the thread rewinding amount is sufficient, set "None".

And, in step S13, S14, S21, air cylinder 92 is switched on and carries out bobbin thread, in step S11, after rotating hook supporting part 70 is rotated 45 degrees, because rotating hook supporting part 70 is not in the rotation position of 180 degrees, so surface The thread cutter 28 does not perform the upper thread cutting operation.

Moreover, since the judgment in step S12 is not carried out according to the setting content of data item 8, the amount of movement of the cloth feeding platform 13 in step S10 is the original value, and can also be automatically determined by the CPU 111 according to the sewing length ml value. to judge. At this time, a reference value A is set in advance and compared with the sewing length ml, and if ml<A, the second bobbin threading is performed.

In addition, since the judgment in step S20 is not carried out according to the setting content of data item 9, the amount of movement from the origin position to the sewing start position of the cloth feed table 13 at the start of the next process is the original value, Also can be judged automatically by CPU 111 according to sewing length ml. In this case, compare the preset reference value B with the sewing length ml, and if ml<B, perform the fourth bottom thread fall.

This kind of automatic judgment structure has high convenience.

According to the above keyhole sewing machine 10, as shown in Figure 11, first in step S14, the bottom thread 38 is pulled out by the bottom thread reeling plate 84, in this state the bottom thread 38 is cut off by the bottom thread cutting device 37, and then the bottom thread reeling plate 84 resets, unclamps bottom thread 38 and closes bottom thread cutting device 37, and movable cutter 50 and clamp thread releaser 64 are forwarded to original position. At this time, the pressing plate of the lower thread 38 is in an instantaneous release state by the action part 65 . However, the lower thread 38 does not fall out of the clamping mechanism 55 due to slack.

That is, since the lower thread 38 is loose before the clamp is released after the lower thread is cut, the lower thread 38 will not fall off from the clamping mechanism 55 (clamping member) even if the type of the lower thread and the load on the thread supply side are large. Good keyhole stitches are smoothly formed without skipping stitches in the next sewing process.

And, since the lower thread 38 is in the state of being stretched by the lower thread reeling plate 84 before cutting, the lower thread 38 is easily cut because a certain degree of tension is applied to the lower thread 38. In addition, the bobbin thread rewinding in steps S13 and S21 is carried out in consideration of the amount of movement of the cloth feeding table 13 and according to the contents of data item 8 and data item 9 set through the operation panel 150, so it is necessary to correspond to the amount of movement. The bottom thread 38 is poured out smoothly to prevent excessive tension being applied to the bottom thread 38 when the cloth feeding table 13 moves.

Especially according to step S13, if no excessive tension is applied to the lower thread 38 before cutting, the lower thread 38 can be reliably in a loose state when the clamping mechanism 55 is released after cutting. In addition, according to step S21, since an excessive tension is not applied to the bobbin thread 38 clamped by the clamping mechanism 55, it does not matter even if the clamping force of the clamping mechanism 55 is weak, so that the components constituting the clamping mechanism 55 can be made small change.

Variation

In the above-mentioned embodiment, with regard to the data items 8 and 9, one graphic data is selected, and the data in the selected graphic data is set and selected as an object, but as shown in FIGS. 12 and 13, it is also possible to set The memory switch (memory switch) is set as the sewing condition irrespective of the figure.

Fig. 12(a) is a schematic diagram of another exemplary operation panel (selection mechanism) 200 as the operation panel of the keyhole sewing machine of the present invention. FIG. 12( b ) is a table t4 for setting and displaying the content of the storage conversion number by the operation panel 200 . This table t4 is stored in ROM112, for example.

The operation panel 200 is composed of a ready key 201 , a storage conversion number selection unit 202 and a data value setting unit 203 .

The ready key 201 is a switch for entering the memory conversion setting mode, and is also a switch for storing the contents set in the memory conversion setting mode.

The storage conversion number selection unit 202 is a selector for selecting a storage conversion number, and the storage conversion number currently selected is displayed on the storage conversion number display unit 202a. Use the + key 202b and - key 202c located below the storage conversion number display part 202a to change the numbers in 1 to 8 in order to select a different storage conversion number.

The data value setting unit 203 is for setting the value of the storage conversion selected by the storage conversion number selection unit 202, and displays the currently set data value on the numerical value display unit 203a. And by operating the + key 203b and - key 203c below the numerical value display part 203a, the number of the numerical value display part 203a is increased or decreased sequentially according to the specified interval within the specified range to change its value.

The contents of storage conversion, such as the moving speed and moving amount in the Y feed direction at the time of thread cutting, are well-known contents for No. 1 to No. 6, so the description will be omitted in the present invention.

Storage conversion No.7 is the same as data item 8 of the above-mentioned table t1, and is used to set whether to carry out the content of bobbin thread rewinding for the second time (Figure 11, step S13), and storage conversion No.8 is the same as the above-mentioned data item 9 , which is used to set whether to perform the fourth bobbin thread rewinding (Fig. 11, step S21). In either case, "1" is set if performed, and "0" is set if not performed.

FIG. 13 is a schematic flow chart of setting processing in the memory conversion setting mode. This process is started by turning on the power while pressing the ready key 201 .

When this process starts, "1" is displayed on the storage conversion number display part 202a in step J1. Then in step J2, judge whether operation + key 202b,-key 202c is operated, if operated then in step J3 according to its operation, update the display content of storage conversion number display part 202a successively, enter step J4. If it is judged that no operation has been performed in step J2, go to step J4. And, corresponding to the display of the storage conversion number display unit 202a, the standard value of the number is displayed on the numerical value display unit 203a of the data value setting unit 203.

In step J4, it is judged whether the + key 203b, - key 203c of the data value setting part 203 is operated. If it is operated, the display content of the numerical value display part 203a is updated for each predetermined unit corresponding to the operation of step J4 in step J5, and the process proceeds to step J6. If it is judged in step J4 that it has not been operated, go to step J6.

In step J6, judge whether ready key 201 is operated, if not operated then return to step J2, if operated then in step J7, write the content of the stored conversion that steps J2～J5 sets into the EEPROM (electricity not shown) erasable programmable read-only memory), and end the process.

In addition, the present invention is not limited to the above-described embodiments, and specific shapes, structures, and the like can be appropriately changed.

For example, the thread adjuster 76c may also be constituted by a so-called actual tension mechanism that is electrically controlled using a solenoid or the like. It is automatically used as the release state before the next sewing starts.

According to the keyhole sewing machine according to the present invention, firstly, the lower thread rewinding mechanism executes the predetermined operation from the initial state to rewind the lower thread. Return the bobbin thread rewinding mechanism to the original state, and after the bobbin thread is slack, the clamping part is in a state where the bobbin thread can be released by the releasing part. At this moment, the lower thread never falls out of the clamping part due to slack.

That is, since the bobbin thread is in a loose state before the release state of the clamping mechanism, even if the type of the bobbin thread and the load on the thread supply side are large, the bobbin thread will not fall off from the upper part of the clamping part. Jump stitches, etc. do not occur, and good lockstitch stitches can be formed smoothly.

And, since the lower thread is in the state of being rewound by the lower thread reeling device before cutting, so the lower thread is applied with a certain degree of tension and cut off more easily.

According to the keyhole sewing machine of the second aspect of the present invention, before the lower thread is cut off, it is possible to select whether the lower thread is rewound by the lower thread rewinding device and loosened by the selection mechanism. Therefore, when the consumption of the lower thread is large, the selection mechanism can be used to select the lower thread to prevent excessive tension on the lower thread when the cloth feeding table moves. At the same time, when the moving amount is short and the bobbin thread consumption is small, the selection mechanism can be used to choose not to rewind the bobbin thread, and unnecessary bobbin thread rewinding can be avoided to prevent the bobbin thread from being excessively slack.

According to the keyhole sewing machine of the third invention, the same effect as that of the second invention can be obtained, and at the same time, it can be determined automatically, so it has higher convenience.

According to the keyhole sewing machine of claim 4 of the present invention, if the movement amount of the feed table from the origin position to the sewing position at the start of sewing is long, the bobbin thread on the clamping mechanism of the bobbin thread cutting device on the cloth feed table is clamped sideways. Consumption is also large. According to this invention, it is possible to use the selection mechanism to select whether to use the bobbin thread unwinding device to reel out the bobbin thread and make it slack for the next sewing. Therefore, when the consumption of the bottom thread is large due to the movement at the beginning of the next sewing, use the selection mechanism to select the bottom thread to be poured out, and the thread is poured out in advance, so that excessive tension can be prevented from being applied to the bottom thread when the cloth feeding table for the next sewing is moved. In addition, the so-called not applying excessive tension to the bobbin thread can weaken the clamping force of the clamping member, and can reduce the size of each member constituting the clamping member.

When the moving amount is short and the bobbin thread consumption is small, if the selection mechanism is used to choose not to rewind the bobbin thread, the redundant bobbin thread reeling will not be carried out, so as to prevent the bobbin thread from being too slack.

According to the keyhole sewing machine of the fifth aspect of the present invention, the same effect as that of the fourth aspect of the present invention can be obtained, and at the same time, it can be determined automatically, so it has higher convenience.

Claims (5)

1. A keyhole sewing machine, having: Facing the needle bar arranged on the machine head of the sewing machine frame, the rotary hook device is arranged on the machine base and moves synchronously with the needle bar; The bobbin thread rewinding device is composed of a bobbin thread rewinding mechanism that loosens the bobbin thread by returning to its original state after unwinding the bobbin thread, and a bobbin thread rewinding drive mechanism that drives the bobbin thread rewinding mechanism; A cloth feeding table arranged on the machine base, carrying the sewing product and moving at least between the origin position and the sewing position; The movable cutter for cutting the bottom thread and the clamping part for clamping the bottom thread from before cutting the bottom thread to after cutting the cloth feeding table, and before and after cutting the bottom thread, the clamping part can be inserted into the bottom thread or released. Bottom thread cutting device composed of release parts in bottom thread state; The keyhole sewing machine uses the coordinated action of the needle bar and the rotary hook device to sew the keyhole, and then cuts the bottom thread with the bottom thread cutting device. It is characterized in that: When cutting the bobbin thread, the bobbin thread rewinding mechanism is actuated by the bobbin thread rewinding drive mechanism, and then the bobbin thread is cut off by the bobbin thread cutting device while the bobbin thread is clamped by the clamping part, and then the clamping part is released by the releasing part. Before the state of the bobbin thread, the bobbin thread rewinding mechanism is restored to its original state by the bobbin thread rewinding driving mechanism. 2. The keyhole sewing machine according to claim 1, characterized in that: The cloth feeding table moves from the sewing position to the origin position before the bottom thread is cut after sewing is finished; and there is a selection mechanism for selecting whether the bottom thread is rewound by the bottom thread rewinding device and the bottom thread is loosened before the bottom thread is cut. 3. The keyhole sewing machine according to claim 1, characterized in that: The cloth feeding table moves from the sewing position to the origin position before the bobbin thread is cut after the sewing is finished; according to the moving length from the sewing position to the origin position, it is automatically determined whether the bobbin thread rewinding device will unwind the bobbin thread before the bobbin thread is cut And loosen the bottom line. 4. The keyhole sewing machine according to claim 1, characterized in that: At the beginning of sewing, the cloth feeding table moves from the origin position to the sewing position; and there is an option to choose whether to use the bobbin thread rewinding device to unwind the bobbin thread after the bobbin thread is cut and when the cloth feeding table is moved for the next sewing start And the selection mechanism that makes the bobbin thread loose. 5. The keyhole sewing machine according to claim 1, characterized in that: At the beginning of sewing, the cloth feed table moves from the origin position to the sewing position; according to the moving length from the origin position to the sewing position for the next sewing, it is automatically determined after the bobbin thread is cut and for the next sewing start. When the cloth feeding table is moving, whether the lower thread is poured out by the lower thread rewinding device and the lower thread is loosened.

Images