KR20080013808A - Thread tension guide for sewing machine - Google Patents

Abstract

A thread tension guide apparatus for a sewing machine is provided to inhibit the heat emission of a tension discharge actuator, thereby enhancing the efficiency of the sewing work. The thread tension guide apparatus comprises a tension releasing device. In the tension releasing device, an output shaft protruded by the operation of a tension releasing solenoid separates a pair of thread control dishes and releases the tension of the upper thread. In the thread control dish, the tension releasing device drives to the tension release state and thereafter the tension release state is maintained by a tension maintaining device. At the state that the tension releasing state is continuously maintained by the tension releasing device, a stop device stops the operation of the tension releasing solenoid. The tension maintaining device comprises a tension releasing actuator for switching a combination member. A control box(6) is installed at the lower right end of a sewing machine table(4).

Description

Thread adjusting device of sewing machine {THREAD TENSION GUIDE FOR SEWING MACHINE}

The present invention relates to a thread adjusting device of a sewing machine for imparting tension to an upper thread.

Conventionally, the thread adjusting device is used in various sewing machines, such as this sewing sewing machine and a buttonhole sewing machine. The thread adjusting device tensions the upper thread in the thread supply path from the thread supply to the sewing needle via the cloth. The thread adjusting device is provided with a thread adjusting knob for adjusting the tension of the upper thread. A user (worker) can perform the sewing operation according to sewing elements, such as a kind of processed cloth, cloth thickness, and a conveyance pitch, by operating a thread adjustment knob.

For example, there is a thread adjusting device disclosed in Japanese Patent Application Laid-Open No. 24083. This thread adjusting device has a thread adjusting shaft that penetrates the sewing machine from side to side (see FIG. 1 of the publication). On the right side of the thread adjusting shaft, a pair of left and right thread adjusting plates for fitting the upper thread, a thread adjusting knob, an adjusting plate press for pressing these thread adjusting plates, and a thread adjusting spring are provided. By adjusting the thread adjusting knob, the tension of the upper thread can be adjusted by changing the pressing force of the thread adjusting spring on the thread adjusting plate. Thread relaxation pins are provided on the thread adjusting shaft. As for the thread release pin, the right end part contacts the center part of an adjustment dish presser, and the left end part contacts the plunger of a thread relaxation solenoid. In this sewing machine, the thread relaxation solenoid is driven when the thread is cut. At this time, the thread relaxation solenoid moves the thread relaxation pin to the right with the plunger. By the movement of this thread release pin, the adjustment plate presser moves to the right to compress the thread adjustment spring. As a result, the pair of thread adjusting dishes can be separated from each other, and the tension applied to the upper thread is released in an instant.

Even when the thread is not cut, the tension of the upper thread may be released (that is, the thread is loosened) in some cases. For example, when sewing the pattern repeatedly, there is a case where the thread is relaxed without cutting the thread each time the pattern sewing is finished. In this state of thread relaxation, the processed fabric piece sewn out is taken out, and the processed fabric piece next sewn is prepared. At this time, it is necessary to maintain the release state of the tension of the upper thread by driving the thread relaxation solenoid of the thread adjusting device. The thread relaxation solenoid increases the amount of heat generated in proportion to the driving time or the magnitude of the driving current. If the thread relaxation time is long, there is a problem that the excitation coil of the thread relaxation solenoid burns out and breaks.

Recently, in order to prevent such an excitation coil from burning off, there is a sewing machine provided with an operation timer in the control device. In this sewing machine, at the end of sewing, the cloth stopper is automatically raised, and at the same time, the thread relaxation solenoid is operated, and the time operation of the operation timer is started.

When a predetermined time elapses from the start of the time-keeping operation, the cloth stopper is lowered to forcibly stop the drive of the real relaxation solenoid. In this case, depending on the predetermined time for which time is measured by the operation timer, the fabric presser descends while pulling out the piece of the finished piece of pattern stitching or during the preparation of the next piece of processed piece of cloth while the tension is applied to the upper thread. There is a problem that will interrupt the work.

An object of the present invention is to provide a thread adjusting device for a sewing machine that can suppress the heat generation of the tension releasing actuator to improve the efficiency of sewing work even if the tension releasing time for releasing the tension applied to the upper thread is long. .

According to the present invention, tension is applied to the upper thread by the pressing force of the pair of thread adjusting plates, and the output shaft protruding by the drive of the tension release solenoid is spaced apart from each other to give the upper thread to the upper thread. A thread adjusting device for a sewing machine having a tension releasing mechanism for releasing tension, comprising: a releasing holding mechanism for maintaining the tension releasing state after driving the tension releasing mechanism in a tension releasing state by the tension releasing solenoid; And a stop mechanism for stopping the driving force of the tension release solenoid while the tension release mechanism continues the tension release state by the release maintenance mechanism.

At the time of sewing, the upper thread is appropriately tensioned by the pair of thread adjusting dishes of the thread adjusting device. In releasing the thread at the start of sewing, cutting the thread at the end of sewing, and the like, when releasing the tension to be applied to the upper thread, the tension release solenoid is energized. By this energization, when the tension release solenoid drives the tension release mechanism to the tension release state, the release maintenance mechanism maintains the tension release state of the tension release mechanism. In this case, even if the stop mechanism stops the driving force of the tension release solenoid, the tension release mechanism continues the tension release state. Therefore, even when the tension release time is long, the heat generation of the tension release solenoid can be suppressed. In the sewing work such as pattern sewing described above, the problem of stopping the work can be solved, and the efficiency of the sewing work can be improved.

In the present invention, the release-release mechanism includes a to-be-engaged portion provided on the output shaft of the tension-releasing solenoid, a joining portion that can be coupled to the to-be-engaged portion, and a non-engaged position for not coupling the engaging portion to the to-be-engaged portion. And it is preferable to have a releasing holding | maintenance actuator which switches and drives to the engagement position couple | bonded with the said to-be-engaged part. According to this, the engagement portion can be switched between the non-engagement position and the engagement position by the release-retention actuator, so that the tension release state can be reliably maintained.

In this invention, it is preferable that the said release maintenance actuator is an electric motor. According to this, it is possible to reliably switch the engaging portion to the non-engaged position and the engaged position by using the large torque of the electric motor.

In the present invention, the release-retaining actuator may be an air cylinder. According to this, the engagement portion can be reliably switched between the non-engagement position and the engagement position using the reciprocating motion of the air cylinder. A large driving force by the air cylinder can be obtained, and the tension release state of the tension release mechanism can be maintained more reliably.

In this invention, it is preferable to arrange | position the said air cylinder on the opposite side to the said tension release mechanism with respect to the said tension release solenoid. Space is empty on the opposite side of the tension release mechanism. Therefore, since there are few installation restrictions, an air cylinder can be arrange | positioned easily.

In this invention, it is preferable to arrange | position the said air cylinder so that the output shaft of the said air cylinder and the output shaft of the said solenoid may be on the same axis line. According to this, the reciprocating operation of the air cylinder can be performed on the same axis as the output shaft of the solenoid. Therefore, the tension released state can be maintained without causing distortion in the engagement portion, coupling portion, solenoid or the like when the air cylinder is driven.

In this invention, it is preferable to have a buffer part in the front-end | tip of the output shaft of the said air cylinder. According to this, the impact at the time of engaging the engaging part and the to-be-engaged part can be alleviated.

<First Embodiment>

EMBODIMENT OF THE INVENTION Hereinafter, it demonstrates, referring drawings for 1st Embodiment of this invention. This embodiment is an example in which this invention is applied to the thread adjusting device of the buttonhole sewing machine which forms a buttonhole stitch.

As shown in FIG. 1, the buttonhole sewing machine M is provided on the sewing machine table 4. The control box 6 is provided in the lower right end part (the arrow direction is forward in FIG. 1) of the sewing machine table 4. As shown in FIG. In the front part of the control box 6, the operation panel 7 for inputting various pattern data which forms a buttonhole stitch (not shown) or a buttonhole is provided. The control box 6 is provided with the control apparatus 8 (refer FIG. 7) which performs various sewing control. The sewing machine motor 5 is provided in the lower center portion of the sewing machine table 4. The sewing machine motor 5 rotates the sewing machine main shaft (not shown) by the timing belt which is not shown by the drive. The foot pedal 9 mentioned later is provided in the leg part 4a of the sewing machine table 4 so that rotation operation is possible.

The buttonhole sewing machine M has a bed portion 1, a leg pillar portion 2 extending upward from the rear portion of the bed portion 1, and a front portion extending from the upper portion of the leg pillar portion 2. It has an arm part 3. A needle bar (both not shown) having a sewing needle is provided at the front end of the arm portion 3. Rotation of the main shaft of the sewing machine drives the needle bar up and down through a needle rod drive mechanism (not shown). In addition to the needle bar drive mechanism, the thread adjusting device 38 described later is provided on the arm portion 3. In the upper surface of the bed part 1, a conveyance table (all of which is not shown) which supports a process cloth is provided. The conveyance table moves (cloth conveyance) by the conveyer drive mechanism which is not shown in figure. The bed part 1 is provided with a rotary cover (not shown) which cooperates with the sewing needle to form a buttonhole stitch.

A pressing rod 16 having a cloth tab 25 is provided at the front end of the arm portion 3. The cloth pressing device 10 which drives this pressing rod 16 up and down is demonstrated using FIG. 2 (the left side of FIG. 2 is front).

The L-shaped lever 11 is rotatably supported by the support shaft 13 extending in the left-right direction by the sewing machine frame of the front end of the arm part 3. The L-shaped lever 12 is rotatably supported on the sewing machine frame of the rear end of the arm portion 3 by a support shaft 14 extending in the horizontal direction. The link plate 18 extending in the front-back direction is disposed between the L-shaped lever 11 and the L-shaped lever 12. The link plate 18 has a front end connected to one end of the L-shaped lever 11, and a rear end connected to one end of the L-shaped lever 12.

The other end of the L-shaped lever 11 is connected to the upper end of the pressing rod 16 via a link member 15. The cloth tab 25 is detachably attached to the lower end of the press bar 16.

The other end of the L-shaped lever 12 is connected to the upper end of the link member 17 extending from the thread cutting mechanism 30 described later. An engagement pin 24 projecting to the right side is fixed below the link member 17. The cloth pressing motor 19 is disposed at the rear side of the link member 17. The disc 20 is fixed to the drive shaft of the cloth pressing motor 19. An engaging pin 21 projecting to the right side is fixed to one end of the disc 20. The rocking lever 23 is supported on the sewing machine frame near the cloth pressing motor 19 so as to be swingable up and down by a support pin 22 extending in the horizontal direction. The swing lever 23 is formed with a first two forked portion 23a and a second two forked portion 23b as shown in FIG. The swing lever 23 engages with the engagement pin 21 of the disc 20 at the first two forks 23a, and with the engagement pin 24 of the link member 17 at the second two forks 23b. Combining

The position of the disc 20 and the coupling pin 21 shown by a solid line in FIG. 2 is called an initial position. In this case, the cloth stopper 25 is in the raised position Pu (see the solid line in FIG. 2) spaced apart from the upper surface of the bed part 1 by a predetermined distance. When the cloth pressing motor 19 is rotated forward, the original plate 20 rotates clockwise in FIG. At this time, the swing lever 23 engaged with the engagement pin 21 swings from the lowered position indicated by the solid line to the upper swing position (see the two-dot chain line) by a predetermined amount. At the same time, the link member 17 moves upward with the engaging pin 24 that engages the second two forked portions 23b to rotate the L-shaped lever 12 counterclockwise. The rotation of the L-shaped lever 12 is transmitted to the L-shaped lever 11 through the link plate 18 to move the pressing rod 16 downward by a predetermined amount. Thereby, the cloth stopper 25 descends to the pressing position Pp (refer to the dashed-dotted line of FIG. 2) which presses the process cloth onto the bed part 1.

When the cloth pressing motor 19 is rotated in reverse, the original plate 20 rotates in the counterclockwise direction, and the swing lever 23 swings from the swing position to the down position. At the same time, the link member 17 moves downward to rotate the L-shaped lever 12 clockwise. The rotation of the L-shaped lever 12 is transmitted to the L-shaped lever 11 through the link plate 18, thereby returning the pressing rod 16 to its original position. Thereby, the cloth stopper 25 rises from the pressing position Pp to the rising position Pu.

The relationship between the cloth pressing device 10 and the depression pedal 9 will be described with reference to FIGS. 1 and 7.

The depression pedal 9 is in the reference position shown in FIG. 1 when there is no operation. The depression pedal 9 rotates to the depression position in which the depression is larger in the front side than the reference position, and the depression return position in depression in the rear side than the reference position. A connection rod 26 extending upward is connected to the depression pedal 9. The pedal position detection mechanism (not shown) is provided below the sewing machine table 4, and the upper end part of the connecting rod 26 is connected to the input lever of the pedal position detection mechanism.

The pedal position detection mechanism includes a potentiometer 72 (see Fig. 7). The control device 8 described later receives the output voltage from the potentiometer 72 to detect the reference position, the depression position, and the depression return position as the operation position of the depression pedal 9. The cloth pawl 25 is at the raised position Pu when the stepped pedal 9 is at the reference position. When the depression pedal 9 is pressed in to the depression position, the cloth pressing motor 19 rotates forward to lower the cloth presser 25 to the pressing position Pp. When the depression pedal 9 is pressed in to the depression return position, thread cutting is performed, and the sewing machine motor 5 stops driving, and the cloth presser motor 19 reversely rotates to raise the cloth presser 25 to the lifted position ( To Pu).

Next, the yarn cutting mechanism 30 for cutting the upper yarn and the lower yarn extending from the fabric will be described with reference to FIG.

The needle plate 1a is provided in the upper surface of the bed part 1. The needle hole 1b through which the sewing needle passes is formed in the needle plate 1a. The movable blade 31 is arrange | positioned under the needle plate 1a. The movable blade 31 is rotatably supported by the screw 32 at the lower side of the needle plate 1a. Immediately below the movable blade 31, a fixed blade 33 having a substantially L shape is disposed in plan view. The fixed blade 33 is fixed to the needle plate 1a by a fixing screw (not shown), and the installation position can be adjusted. A downward blade portion 33a is formed at the tip of the fixed blade 33.

An acute angle seal handling portion 31a is formed at the tip of the movable blade 31. A gentle curved thread guide portion 31c is formed in the thread handling portion 31a to guide the ceiling upper thread continuously. Subsequent to this thread guide portion 31c, a curved thread capture portion 31d is formed which catches the upper-side upper thread guided by the thread guide portion 31c. A circular blade portion 31b is formed in the vicinity of the seal handling portion 31a of the movable blade 31.

3 shows the state before the movable blade 31 reciprocates in solid line. The position of this movable blade 31 is called a standby position. The front end of the swing lever 34 extending in the front-rear direction is connected to the right end (in FIG. 3) of the movable blade 31. The rear end of the swing lever 34 is connected to a thread cutting drive mechanism (not shown). This thread cutting drive mechanism is connected to a thread cutting solenoid 78 (see Fig. 7). By driving the thread cutting solenoid 78, when the swing lever 34 is driven forward by a predetermined stroke through the thread cutting drive mechanism, the movable blade 31 is moved from the standby position to the position indicated by the two-dot chain line in the clockwise direction. Turn forward (forward). The position of the movable blade 31 at this time is called a rotation position.

The movable blade 31 guides the left upper thread and the lower thread to the thread capturing part 31d side via the thread guide part 31c during this advance.

When the driving of the thread cutting solenoid 78 is stopped, the swing lever 34 is driven backward by a predetermined stroke by a spring force of a return spring (not shown). In this case, the movable blade 31 reversely rotates (returns) counterclockwise from the rotation position to the standby position. At the time of this return, the movable blade 31 feeds out the upper thread on the sewing needle side by a predetermined amount in order to move forward the cloth upper and lower threads in the state where the thread catching portion 31d is replenished. By the return of this movable blade 31, the blade part 33a of the fixed blade 33 and the blade part 31b of the movable blade 31 meet and cut | disconnect a ceiling side upper thread and a lower thread simultaneously.

In this thread cutting, in order to feed out the needle needle side upper thread, it is necessary to release the tension given to the upper thread. By releasing this tension, the edge part of the upper thread after cutting can be prevented from falling out from the sweat hole of the sewing needle at the next sewing start. In the present embodiment, the tension adjustment device 38 and the tension release mechanism 39 described later provide the tension to the upper thread and release the tension.

Next, the thread adjusting device 38 for applying tension to the upper thread will be described.

As shown in FIG. 4, the support frame 3c which connects the right side frame 3a and the left side frame 3b below the arm part 3 is provided integrally. The support frame 3c has a hollow rod shape as a whole, and the following hole portions are formed. The small diameter hole part 3d which accommodates the intermediate | middle rod 49 mentioned later so that sliding to the left-right direction is formed in the right half part of the support frame 3c is formed. A large diameter hole portion 3f having a larger diameter than the small diameter hole portion 3d is formed in the left half portion of the support frame 3c. The large diameter hole part 3f and the small diameter hole part 3d are continued through the inclination step part 3e.

The fixing hole 3g which communicates with the small diameter hole part 3d is formed in the right side frame 3a. The cylindrical fixing part 3h which protrudes to the right side is formed in the peripheral part of this fixing hole 3g. A cylindrical thread adjuster 36 is accommodated in the fixing hole 3g. The thread adjuster 36 is fixed to the fixing part 3h by the fixing screw 37. As shown in FIG. As shown in Fig. 5, a cylindrical bearing hole 36a is formed on the left side of the thread adjuster 36, and a spring receiving hole 36b continues to the bearing hole 36a on the right side. Is formed.

4 and 5, the thread adjusting device 38 includes a thread adjusting shaft 41, a pair of thread adjusting plates 42 and 43, a thread adjusting spring 44, and a thread adjusting screw 45. Etc. are provided. The thread adjusting shaft 41 has a small diameter shaft portion 41a on the left side, a large diameter shaft portion 41b continuous to the right side of the small diameter shaft portion 41a, and a screw continuous to the right side of the large diameter shaft portion 41b. It has the formation shaft part 41c integrally. The male screw is formed in the outer peripheral part of the screw formation shaft part 41c. In the center of the screw forming shaft portion 41c, slits having a predetermined width are formed left and right, and a pair of upper and lower pairs of protrusions having a cross-sectional half moon shape are formed. In the small diameter shaft portion 41a and the large diameter shaft portion 41b, insertion through holes 41e penetrating these shaft center portions are formed. The drive rod 46 mentioned later is inserted through this insertion hole 41e. The thread adjustment shaft 41 is fixed to the thread adjuster 36 with the fixing screw 47 in a state where the small diameter shaft portion 41a is inserted through the bearing hole 36a of the thread adjuster 36. It is.

The pair of thread adjusting plates 42 and 43 shown in Figs. 4 and 5 face each other, and the left side constitutes the thread adjusting plate 42 on the fixed side, and the right side constitutes the thread adjusting plate 43 on the pressing side. do. The insertion hole 42a which is slightly smaller in diameter than the outer diameter of the large-diameter shaft part 41b is formed in the center part of the thread adjusting dish 42 on the fixed side. A pair of insertion holes 43a through which a pair of screwing shaft portions 41c can be inserted are formed in the center portion of the thread adjusting dish 43 on the pressing side. The fixed side thread adjustment plate 42 engages the insertion through-hole 42a from the right side by fitting it into the right end step portion 41d of the large diameter shaft portion 41b of the thread adjustment shaft 41. The thread adjusting pan 43 on the pressing side is arranged to be in contact with the right side of the thread adjusting pan 42 on the fixed side. At this time, the pair of screwing shaft portions 41c is inserted into the pair of insertion holes 43a. The thread adjustment spring 44 is provided in the outer peripheral part of a pair of screw formation shaft part 41c which protruded to the right side of the thread adjustment pan 43 of the press side. The thread adjustment screw 45 is arrange | positioned at the right end part of this screw formation shaft part 41c. The thread adjusting screw 45 is formed with a female screw on the inner circumference thereof, and its rotation operation is possible.

When the operator rotates the thread adjusting screw 45 in the clockwise direction when viewed from the right side, the thread adjusting screw 45 moves to the thread adjusting pan 43, and the spring force of the thread adjusting spring 44 becomes strong. Thus, the tension of the upper thread supplied between the pair of thread adjusting plates 42 and 43 increases. When the operator rotates the thread adjusting screw 45 in the counterclockwise direction when viewed from the right side, the thread adjusting screw 45 is moved away from the thread adjusting plate 43 so that the spring force of the thread adjusting spring 44 is weak. Become. Therefore, the tension of the upper thread supplied between the pair of thread adjustment plates 42 and 43 becomes small. In this way, the thread adjustment screw 45 is rotated and the tension of the upper thread is appropriately adjusted, so that sewing according to the type and thickness of the fabric to be sewn and the type and thickness of the upper thread to be used can be performed.

The tension release mechanism 39 for releasing the tension applied to the upper thread by separating the pair of thread adjustment plates 42 and 43 from each other will be described. The tension releasing mechanism 39 has an intermediate rod 49 for releasing tension acting by the thread adjusting device 38 and the driving rod 46.

As shown in Figs. 4 and 5, the drive rod 46 has a predetermined length and is inserted through an insertion through hole 41e penetrating the small diameter shaft portion 41a and the large diameter shaft portion 41b. The right end of the drive rod 46 penetrates the insertion through hole 42a of the thread adjusting pan 42 on the fixed side to be able to contact the central portion of the thread adjusting pan 43 on the pressing side. As shown in Fig. 4, the intermediate rod 49 has a predetermined length and is disposed in the large diameter hole portion 3f and the small diameter hole portion 3d of the support frame 3c. The right end of the intermediate rod 49 is capable of pressing the left end of the drive rod 46 to the right.

The compression coil spring 52 is provided in the outer peripheral part of the intermediate rod 49 by the side of the large diameter hole part 3f. The intermediate rod 49 has a pair of washers 50 and washers 51 respectively engaged at right and left sides of the compression coil spring 52. The outer diameter dimension of these washers 50 and the washer 51 is set slightly smaller than the diameter dimension of the large diameter hole part 3f. In the intermediate rod 49, it is located just to the left of the left washer 51, and the "E" shaped stop ring 53 is provided. The stop ring 53 positions the left end position of the left washer 51.

As shown in Fig. 4, the tension release solenoid 55 (corresponding to the tension release actuator) is disposed outside the left side frame 3b in the right orientation. The left end of the intermediate rod 49 is fixed to the right end of the output shaft 55a of the tension release solenoid 55 by the fixing nut 54.

When the tension release solenoid 55 is not operated, the washer 50 on the right side always contacts the inclined step portion 3e from the left side by the spring force of the compression coil spring 52. The retracted position in which the intermediate rod 49 and the output shaft 55a are integrally moved to the left through the washer 51 and the stop ring 53 on the left side by the spring force of the compression coil spring 52 (see Fig. 4). ) Is pressed. A gap is provided between the right end of the intermediate rod 49 and the left end of the drive rod 46.

The tension release solenoid 55 operates on the tension release side by energization, thereby driving the tension release mechanism 39 in the tension release state. In this case, the intermediate rod 49 and the output shaft 55a move integrally against the spring force of the compression coil spring 52, and move to the forward position (see Fig. 10) that is moved to the right by a predetermined stroke from the retracted position. It is switched. Thereby, the drive rod 46 protrudes to the right side, presses the center part of the thread adjusting pan 43 on the press side to the right, and separates the thread adjusting pan 43 on the press side from the thread adjusting pan 42 on the fixed side. In this way, the tension applied to the upper thread is released between the pressing-side thread adjusting pan 43 and the fixed-side thread adjusting pan 42.

Next, the release maintenance mechanism 56 which maintains the tension release state of the tension release mechanism 39 is demonstrated. The release holding mechanism 56 includes a to-be-coupled plate 57 provided on the tension-releasing solenoid 55, a coupling plate 59 that can be coupled to the to-be-coupled plate 57, and a release to drive the coupling plate 59. The holding motor 58, the control apparatus 8 mentioned later, etc. are comprised.

As shown in Fig. 4, the output shaft 55a of the tension release solenoid 55 extends to the left side of the tension release solenoid 55. As shown in Fig. 6, a circular engagement plate 57 (corresponding to the engagement portion) is fixed to the fixing bolt 60 at the left end of the output shaft 55a. The release holding motor 58 (corresponding to the release holding actuator) is fixed to the left frame 3b immediately above the tension release solenoid 55. The engaging plate 59 (corresponding to the engaging portion) is fixed to the drive shaft 58b of the release holding motor 58 with the fixing bolt 61.

As shown in Fig. 6, the coupling plate 59 is cut out in a half moon shape in a part of the circle. As shown in FIG. 4, the guide part 59a inclined to the lower left side is integrally formed in the cut edge of this coupling plate 59. As shown in FIG. The guide part 59a has an elongate triangular shape in FIG. The coupling plate 59 is disposed between the coupling position where the guide portion 59a faces upwards (see the dashed-dotted line in FIG. 6) and the non-engagement position where the guide portion 59a faces downwards (see solid line in FIG. 6). Rotate half a turn. When the engaging plate 59 is in the non-engaged position, it is not in contact with the engaging plate 57.

At the time of releasing the tension on the upper thread, when the output shaft 55a is switched from the retracted position to the advanced position by driving the tension releasing solenoid 55, the to-be-engaged plate 57 is left position spaced apart from the tension releasing solenoid 55. It switches from (refer FIG. 4) to the right position (refer FIG. 10) near the tension release solenoid 55. FIG.

While the tension release solenoid 55 is being driven, the drive shaft 58b of the release-retaining motor 58 rotates counterclockwise in Fig. 6 to engage the engaging plate 59 in the non-engaged position shown in Fig. 4 from Fig. 10. Rotate to position halfway. At this time, the guide portion 59a of the coupling plate 59 guides the coupling plate 59 to the left side of the coupling plate 57 to couple a portion of the coupling plate 59 to a portion of the coupling plate 57. Let's do it. The coupling plate 59 is sandwiched between the to-be-coupled plate 57 and the release solenoid 55. In this state, even if the driving of the tension release solenoid 55 is stopped by the stop mechanism described later, the coupling plate 59 is coupled to the coupling plate 57 via the output shaft 55a against the spring force of the compression coil spring 52. ) In the forward position. As a result, the tension release mechanism 39 continues the tension release state by the release retention mechanism 56.

In order to give tension to the upper seal, when the tension release state is released, the release maintaining motor 58 rotates counterclockwise in FIG. 6 to rotate the coupling plate 59 from the engaged position to the non-engaged position. .

Since the coupling plate 59 is removed from the coupled plate 57 by this rotation, the coupled plate 57 is moved to the left position by the spring force of the compression coil spring 52 (see Fig. 4). . The tension release mechanism 39 is switched to a tension-providing state, and the pair of thread adjusting plates 42 and 43 are brought into close contact with the spring force of the thread adjusting spring 44 to impart tension to the upper thread.

Next, the structure of the control system of the buttonhole sewing machine M will be described.

As shown in Fig. 7, the control device 8 mainly comprises a microcomputer, and includes a bus 65 such as a CPU 65, a ROM 67, a RAM 68, and a data bus connecting them. 66, an input interface 69, an output interface 70, and the like.

The potentiometer 72, the start stop switch 73, and the operation panel 7 are connected to the input interface 69. The input interface 69 receives an output voltage signal from the potentiometer 72 according to the operation position of the stepped pedal 9. The input interface 69 receives a switch signal from the start stop switch 73 and a control signal from the operation panel 7. A drive circuit 74 for the sewing machine motor 5, a drive circuit 76 for the feed motor 75 for operating the carriage drive mechanism, and a drive circuit for the cloth pressing motor 19 at the output interface 70 ( 77), a drive circuit 79 for the thread cutting solenoid 78, a drive circuit 80 for the tension release solenoid 55, and a drive circuit 81 for the release retaining motor 58, and an operation panel ( 7) is connected. The drive circuit 80 drives the tension release solenoid 55 and stops the drive force based on the drive signal from the output interface 70. This drive circuit 80 and the control apparatus 8 correspond to a stop mechanism. The feed motor 75, the cloth pressing motor 19, and the release holding motor 58 are each composed of a stepping motor.

In the ROM 67, a plurality of types of pattern sewing data for various buttonhole stitches, a sewing control program described later, and the like are stored in advance. Some of the pattern sewing data stores a thread cutting code for automatically cutting the thread at the end of sewing, at the end of the sewing data. In the RAM 68, various memories, counters and buffers necessary for various controls are provided, and various memories for storing primarily the calculation results calculated by the CPU 65 are provided.

The control apparatus 8 drives and controls actuators, such as the sewing machine motor 5, according to a sewing control program and pattern sewing data, forms a buttonhole stitch with respect to a workpiece | work cloth, and performs thread cutting or tension release.

Sewing control performed on the control device 8 will be described with reference to FIG. Fig. 8 shows a flowchart of sewing control, and reference symbols Si (i = 11, 12, 13, ...) indicate respective steps.

At the time of power-on of the buttonhole sewing machine M, the cloth stopper 25 is raised to the raised position Pu and is not energized by the tension release solenoid 55, so that the thread adjusting device 38 is connected to the upper thread. Tension is given. By inputting this power supply, the control apparatus 8 first starts the tension release process (refer FIG. 9) which releases the tension | tensile_strength applied to an upper thread for sewing preparation (S11).

The control device 8 drives the tension release solenoid 55 for a predetermined short time (for example, a minute time of about 1 to 2 seconds) by energizing (S31). During the driving of the tension release solenoid 55, the control device 8 rotates the release holding motor 58 forward only half a forward rotation to half the engagement plate 59 to the engaged position (S32).

The control device 8 stops the energization and stops the driving force of the tension release solenoid 55 when a minute elapses after starting the energization to the tension release solenoid 55 (S33), and terminates this tension release process, The flow proceeds to step S12 of sewing control. As described above, since the tension release mechanism 39 continues the tension release state even when the driving force of the tension release solenoid 55 is stopped, the pressing side thread adjusting dish 43 is spaced apart from the fixed side thread adjusting dish 42. Continue to become the state (ie to release the tension given to the upper thread). The control apparatus 8 which performs step S31, step S32, and step S33 is corresponded to a stop mechanism.

In sewing control, when the operator presses the depression pedal 9 to the depression position in order to start sewing (S12: YES), the control device 8 rotates the cloth pressing motor 19 forwardly and presses the cloth opening 25 ) Is lowered to the pressing position Pp (S25). The controller 8 reversely rotates the release holding motor 58 only half a rotation, and makes the coupling plate 59 half-turn to the non-engagement position (S26). As a result, the tension release mechanism 39 is switched to the tension-providing state, and the pair of thread adjusting plates 42 and 43 are brought into close contact with each other to apply tension to the upper thread.

When the depression pedal 9 is returned to the original reference position (S12: No), the operator operates the start stop switch 73 ON to start sewing (S13: Yes). By this ON operation, the control apparatus 8 drives the sewing machine motor 5 (S14), rotates a sewing machine main shaft, drives a needle rod, and performs a sewing process (S15). In this sewing process, based on the pattern sewing data of the button hole previously selected, the feed motor 75 is driven every time the sewing data for one stitch is read from the first needle drop position data, and is conveyed through the feed table drive mechanism. Drive the stage to cloth transfer.

When the sewing process is not finished (S16: No), the control apparatus 8 repeats step S15 and step S16. When the sewing process is finished (S16: Yes), the control device 8 judges the presence or absence of thread cutting, and when it is determined that the thread is cut (i.e., when the thread cutting code is read, S17: Yes), the predetermined yarn Wait until cutting timing (S18: No). When the thread cutting timing is reached (S18: Yes), the control device 8 drives the tension release solenoid 55 by energizing (S19) to release the tension of the upper thread. In this state, the control apparatus 8 performs the thread cutting process by the thread cutting mechanism 30 (S20).

The control device 8 stops driving of the sewing machine motor 5 (S21), rotates the release holding motor 58 forward only by half rotation, and rotates the coupling plate 59 half to the engaged position (S22). . In this state, the control apparatus 8 stops the driving force of the tension release solenoid 55 (S23). In this case, since the tension release mechanism 39 continues the tension release state, the state in which the tension applied to the upper thread is released continues.

The control apparatus 8 reversely rotates the cloth pressing motor 19 to raise the cloth presser 25 to the raised position Pu (S24). In this state, the worker can take out the processed cloth which finished sewing.

The control apparatus 8 which performs step S19, step S22, and step S23 is corresponded to a stop mechanism.

When the sewing process is finished (S16: Yes), when the control device 8 determines that there is no thread cutting (that is, when there is no thread cutting code to read, S17: No), the drive of the sewing machine motor 5 is stopped. (S27). The control apparatus 8 performs said tension release process (S28), and returns a process to step S12. In this case, the worker prepares for the next sewing. The control apparatus 8 repeats after step S12.

At the time of thread cutting by the thread cutting mechanism 30, in the case of releasing the tension applied to the upper thread, the tension release solenoid 55 is energized. By this energization, once the tension release solenoid 55 is operated to the tension release side, the release maintenance mechanism 56 can maintain the operation state to the tension release side. In this case, since the stop mechanism (control device 8) stops the driving force of the tension release solenoid 55 in the state where the tension release mechanism 39 continues the tension release state, the tension is released even when the tension release time is long. The heat generation of the release solenoid 55 can be suppressed.

For example, when sewing the buttonhole stitch which is a pattern stitch repeatedly to a piece of processed cloth, tension release may be performed without thread cutting every time the pattern sewing is finished. In this case, in the state of tension releasing, the processed cloth piece sewn out is taken out, and the next processed cloth piece is newly prepared. At this time, the tension releasing solenoid 55 is driven as shown in FIG. 10, but the driving force of the tension releasing solenoid 55 can be stopped after a small time elapses.

That is, the release maintaining mechanism 56 drives the tension release solenoid 55 by a minute time during the tension release treatment (see FIG. 9), and drives the release plate holding motor 58 to drive the coupling plate 59 during its drive. Switch to the mating position. Thereby, since the tension release state can be maintained, the energization to the tension release solenoid 55 at the time of tension release can be completed in a minute, and the heat generation of the tension release solenoid 55 can be made none. Therefore, since the tension release state can be continued for a long time, the problem of work interruption in the conventional thread adjusting apparatus mentioned above can be solved and the efficiency of sewing work can be improved. Since the driving force of the tension release solenoid 55 is stopped when the engagement plate 59 is engaged with the engagement plate 57, the operation state to the tension release side of the tension release solenoid 55 can be reliably maintained.

The tension releasing actuator was composed of a tension releasing solenoid 55 which is a solenoid. Due to the quick response of the solenoid, the tension of the upper thread can be released quickly, and the thread can be cut smoothly. The release maintenance actuator was comprised with the release maintenance motor 58 which is an electric motor. By using the large torque of this electric motor, the engagement plate 59 can be reliably switched to a non-engagement position and an engagement position, and the tension release state can be reliably maintained.

<2nd embodiment>

11 and 12 show a second embodiment of the present invention, and a part different from the first embodiment will be described. The same code | symbol is attached | subjected to the same part as 1st Embodiment.

In the second embodiment, as shown in FIG. 11, the release holding cylinder 58A made of an air cylinder is used instead of the release holding motor 58. As shown in FIG. The release holding cylinder 58A is fixed downward to the mounting table 3i provided on the left frame 3b. The plunger 58a of the release holding cylinder 58A corresponds to the engaging portion. The guide part which inclines below left is formed in the front-end | tip part 58c of the plunger 58a. In the state where the release holding cylinder 58A is not driven, the plunger 58a is in a non-engaged position in which the distal end portion 58c is retracted above the engaging plate 57. When the release holding cylinder 58A is driven when the tension is released, the plunger 58a moves downward as shown in FIG. At this time, the distal end portion 58c of the plunger 58a guides the plunger 58a to the left side of the plate to be joined 57 and switches to a coupling position where the portion of the plate 57 is engaged from the left side.

In the above configuration, the tension releasing solenoid 55 is once driven for a short time, and the releasing retaining cylinder 58A is driven to switch the plunger 58a to the engaged position during the driving. At this time, even if the stop mechanism (control device 8) stops the driving force of the tension release solenoid 55, the operation state of the tension release solenoid 55 to the tension release side can be maintained.

According to the second embodiment, similarly to the first embodiment, even when the tension release time for releasing the tension applied to the upper thread becomes long, the heat generation of the tension release solenoid 55 can be suppressed. Thereby, since the tension release state can be continued for a long time, the above-mentioned problem of interruption of work can be solved and the efficiency of sewing work can be improved.

The release maintenance actuator was comprised with the release retention cylinder 58A which is an air cylinder. By using the reciprocating motion of this air cylinder, the plunger 58a could be reliably switched to a non-engaged position and a engaged position. A large driving force can be obtained by the air cylinder, and the tension releasing mechanism 39 can be reliably maintained in the tension releasing state through the engaging plate 57. In addition, the same effects as those in the first embodiment can be obtained by the tension release solenoid 55 in which the tension of the upper thread can be quickly released.

Third Embodiment

13 and 14 show a third embodiment of the present invention. In 3rd Embodiment, similarly to 2nd Embodiment, the release maintenance actuator is comprised by the air cylinder and the part different from 2nd Embodiment is demonstrated. The same code | symbol is attached | subjected to the same part as 2nd Embodiment.

The case 89 which covers the tension release solenoid 55 is arrange | positioned outside the left side frame 3b. The case 89 has a box shape with the right side open, and a flange portion 89a is formed to protrude outward from the opening. The case 89 is fixed to the left frame 3b by the fixing screw 90 in the flange portion 89a. The release holding cylinder 58B is disposed on the side opposite to the tension release mechanism 39 with respect to the tension release solenoid 55. In 3rd Embodiment, the release holding cylinder 58B is arrange | positioned so that the plunger 58d and the output shaft 55a of the tension release solenoid 55 may become on the same axis, and are fixed to the inner wall part of the case 89 by right orientation. It is. The plunger 58d of the release holding cylinder 58B has a shock absorbing portion 91 (corresponding to the engaging portion) at the distal end. The shock absorbing portion 91 is formed of an elastic member such as rubber. The shock absorbing portion 91 relieves the impact when the plunger 58d collides with the fixing bolt 60. When the release holding cylinder 58B is not driven, the shock absorbing portion 91 is in a non-engaged position which is retracted to the left along with the plunger 58d of the release holding cylinder 58B (see Fig. 13). When the release holding cylinder 58B is driven at the time of tension release, the shock absorbing portion 91 moves to the right together with the plunger 58d as shown in FIG. At this time, the buffer part 91 is switched to the engagement position which presses the output shaft 55a of the tension release solenoid 55 which operated to the tension release side from the fixing bolt 60 (equivalent to a to-be-engaged part) side.

In the above configuration, the tension release solenoid 55 is once driven for a short time, and the release holding cylinder 58B is driven during the driving to switch the shock absorbing portion 91 to the engaged position. At this time, even if the stop mechanism (control device 8) stops the driving force of the tension release solenoid 55, the operating state of the tension release solenoid 55 on the tension release side can be maintained.

According to the third embodiment, the release holding cylinder 58B is disposed on the axis of the output shaft 55a of the tension release solenoid 55, and the plunger 58d and the output shaft 55a are on the same axis. The reciprocating operation of the cylinder 58B can be performed on the same axis as the output shaft 55a of the tension release solenoid 55. Therefore, when the release holding cylinder 58B is driven, the tension release state can be maintained without causing distortion in the fixing bolt 60, the buffer portion 91, the tension release solenoid 55, and the like.

The release holding cylinder 58B was disposed on the opposite side of the tension release mechanism 39 with respect to the tension release solenoid 55. The other side of this tension release mechanism 39 does not have other members, and there is little restriction on installation. Therefore, the magnitude | size of the release holding cylinder 58B, the shape of the case 89, etc. can be changed arbitrarily, and the freedom of design can be improved. According to the third embodiment, even when the tension release time is lengthened, the same effects as in the second embodiment can be obtained, for example, the heat generation of the tension release solenoid 55 can be suppressed.

As a modification of the third embodiment, the plunger 58d and the output shaft 55a may be disposed slightly up and down without being provided on the same axis.

As another modification of the third embodiment, the output shaft 55a of the tension release solenoid 55 may be used as the engaging portion instead of the fixing bolt 60.

As another modification of the third embodiment, the plunger 58d of the release holding cylinder 58B may be used as the engaging portion instead of the shock absorbing portion 91. The same thing as the fixing bolt 60 may be used for the front-end | tip of the plunger 58d.

In any embodiment, the following changes are included.

1) The sewing machine provided with the thread sewing mechanism which made thread sewing by manual operation WHEREIN: This is a case where time is required for the thread sewing operation by this thread sewing mechanism, and when this tension release time becomes long, this invention is Can be applied. Also in this case, heat generation of the tension releasing solenoid 55 can be suppressed as described above, and the problem of work interruption can be eliminated, so that the efficiency of sewing work can be improved.

2) Although the driving force of the tension release solenoid 55 was stopped by stopping the energization to the tension release solenoid 55, it is not limited to this. The stopping of the driving force of the tension releasing solenoid 55 means not only the driving voltage of 0 volts, but also the case of setting the driving voltage to a small voltage (or weak energization), and the like. It includes a state in which the operation of the tension release side cannot be maintained.

1 is a perspective view of a buttonhole sewing machine showing a first embodiment of the present invention.

2 is a right side view of the cloth pressing mechanism.

3 is a plan view of a thread cutting mechanism;

Figure 4 is a longitudinal front view of the main part of the buttonhole sewing machine.

5 is an exploded perspective view showing a part of components of the thread adjusting device.

6 is a left side view of the bonding plate and the bonded plate.

Fig. 7 is a block diagram showing the configuration of a control system of a buttonhole sewing machine.

8 is a flowchart of sewing control.

9 is a flowchart of tension release control.

Fig. 10 is a longitudinal sectional front view of an essential part in a tension released state;

Fig. 11 is a longitudinal sectional front view of an essential part of a buttonhole sewing machine showing a second embodiment of the present invention.

Fig. 12 is an equivalent view of Fig. 11 in a tension released state.

Fig. 13 is a longitudinal sectional front view of an essential part of a buttonhole sewing machine showing a third embodiment of the present invention.

Fig. 14 is an equivalent view of Fig. 13 in a tension released state.

<Explanation of symbols for the main parts of the drawings>

1: Bed part

2: bridge pillar

3: arm part

6: control box

7: operation panel

10: cloth pressing device

11: L-shaped lever

16: compression rod

25: thousand press

38: thread adjusting device

M: buttonhole sewing machine

Claims (7)

The tension is applied to the upper thread by the pressing force of the pair of thread adjusting plates, and the output shaft projecting by the driving of the tension release solenoid separates the pair of thread adjusting plates from each other to release the tension applied to the upper thread. In the thread adjusting device of the sewing machine provided with a tension releasing mechanism, A release-releasing mechanism for driving the tension-releasing mechanism in the tension-releasing state by the tension-releasing solenoid, and maintaining the tension-releasing state; And a stop mechanism for stopping the driving force of the tension release solenoid while the tension release mechanism continues the tension release state by the release maintenance mechanism. The release mechanism of claim 1, The to-be-engaged part which has the said output shaft of the said tension release solenoid, A coupling part capable of coupling to the coupled part, And a release holding actuator for switching the coupling portion to a non-engagement position that is not coupled to the coupled portion and to an engagement position that couples to the coupled portion. 3. The thread adjusting device of a sewing machine according to claim 2, wherein the release maintaining actuator is made of an electric motor. 3. The thread adjusting device of a sewing machine according to claim 2, wherein the release maintaining actuator is formed of an air cylinder. The thread adjusting device of the sewing machine according to claim 4, wherein the air cylinder is disposed on the opposite side of the tension release mechanism to the tension release solenoid. 6. The thread adjusting device of a sewing machine according to claim 5, wherein the air cylinder is arranged such that an output shaft of the air cylinder and an output shaft of the solenoid are on the same axis. 7. The thread adjusting device of a sewing machine according to claim 6, wherein a buffer part is provided at a distal end of the output shaft of the air cylinder.

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