JP2770442B2 - sewing machine - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a sewing machine, and more particularly, to a needle bar blocking means for blocking a needle bar with respect to a main shaft of a sewing machine, and a thread for stopping a sewing machine motor when a thread breaks. The present invention relates to a sewing machine provided with cut-out detecting means.

[Prior art] As a sewing machine equipped with a conventional needle bar blocking device,
The sewing machine described in Japanese Patent No. 25752 is known. In this sewing machine, a clutch member is provided between the main shaft of the sewing machine and the needle bar, the clutch member is operated by driving a solenoid, and the needle bar is moved to a predetermined position without transmitting the rotational drive of the main shaft of the sewing machine to the needle bar. And a plurality of feeding movements are performed during that time. Further, as a sewing machine provided with a conventional thread breakage detecting device, a sewing machine described in Japanese Patent Publication No. 59-9191 is known. This sewing machine is provided with a thread detection circuit that detects a movement of a thread take-up spring driven by a thread pick-up motion by a balance and generates a thread signal, and the main shaft of the sewing machine rotates a predetermined number of times to prevent a malfunction of the thread breakage detecting device. When no thread signal is generated during this time, it is determined that the thread is broken and the sewing machine motor is stopped.

[Problems to be Solved by the Invention] However, when a thread breakage detecting device is attached to a sewing machine having a conventional needle bar blocking device, there are the following problems. That is, while the needle bar is shut off, no stitches are formed on the work cloth, so that the upper thread is not consumed, and as a result, the thread take-up spring is not driven by the upper thread, so that the thread breakage detecting device malfunctions and the sewing machine motor stops. There is a problem of doing it.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems, and an object of the present invention is to provide a sewing machine equipped with a needle bar cut-off device, which is provided with a thread breakage detection device. An object of the present invention is to provide a sewing machine that does not stop the sewing machine motor due to malfunction of the apparatus.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a sewing machine main shaft that is rotationally driven by a sewing machine motor, a needle bar that is operatively connected to the sewing machine main shaft, and that reciprocates up and down in synchronization with the rotation of the sewing machine main shaft. A needle bar interrupting means for interrupting the operation connection of the needle bar; and a thread break detecting means for detecting a thread break by constantly engaging with the thread and monitoring the movement of the thread. In a sewing machine that stops the sewing machine motor when a thread break is detected by a detection unit, a control for disabling a thread break detection operation of the thread break detection unit while the needle bar is blocked by the needle bar blocking unit. Means.

[Operation] In the sewing machine configured as described above, while the bar needle is blocked by the needle bar blocking means, the control means disables the thread break detection operation of the thread break detection means and inhibits the stop operation of the sewing machine motor. I do.

[Embodiment] The following describes an embodiment of the present invention with reference to the drawings.

First, FIG. 2 shows a sewing machine to which an embodiment of the present invention is applied. The sewing machine frame 1 has a bed 2, a pillar 3 erected from the bed 2, and a pillar 3 thereof. And an upper arm 4 extending horizontally from the upper arm 4. A start / stop switch 70 operable to start or stop the sewing machine is provided on the front surface of the head 5 of the upper arm 4, and a needle bar 6 capable of reciprocating up and down and laterally swinging is provided at the head 5. A sewing needle 7 is attached to a lower end of the needle bar 6.

An opening is formed in the upper surface of the bed 2, and this opening is closed by a needle plate. A plurality of slots are formed in the needle plate, and a known feed dog can project upward from the slots. The feed dog cooperates with the presser foot 8 to feed the work cloth in the above and right and left directions.

In addition, a pattern selection key group 9 operated to select a desired pattern is provided on the front surface of the pillar 3. The pattern selection key group 9 includes a numeric key group consisting of numbers from 0 to 9, a plus key, and a clear key.

The needle bar up / down driving device is the same as that of a normal sewing machine, so that the description thereof will be omitted. Next, a needle bar blocking device 10 for temporarily stopping the vertical movement of the needle bar 6 will be described with reference to FIGS. Will be described.

In the vicinity of the left end of the sewing machine main shaft 35 which is disposed in the upper arm 4 in the left-right direction and rotated by the sewing machine motor 76, a cylindrical set collar 11 is fitted around the sewing machine main shaft 35 and fixed with screws. A concave portion 12 is formed at one portion of the outer peripheral portion of the collar 11 over the entire width in the left-right direction. A crank plate 13 is rotatably fitted to the left end of the set collar 11, and the balance crank 14 is rotatably fitted to the main shaft 35 of the sewing machine in contact with the set collar 11 and the left end surface of the crank plate 13. 13 is fixed to a balance crank 14, and the balance crank 14 is stopped by a stop ring 15 attached to the left end of the sewing machine main shaft 35.

A curved clutch plate 17 is provided on the right side of the crank plate 13.
The base end of the sewing machine spindle is
It is pivotally supported in a plane orthogonal to 35. In the vicinity of the base end of the clutch plate 17, a concave portion 18 that can engage with the concave portion 12 is provided.
Is formed, and the clutch plate 17 is urged by a tension spring 19 in a direction in which the convex portion 18 engages with the concave portion 12. Accordingly, the rotation of the sewing machine main shaft 35 causes the clutch plate 17 to rotate through the engagement between the concave portion 12 and the convex portion 18, and the crank plate 13 and the balance crank 14 to rotate. Reference numeral 20 denotes a balance crank 14.
Is a needle bar crank connected to the crank pin 21 of the first embodiment, and reference numeral 22 is a balance.

Release the engagement between the concave portion 12 and the convex portion 18 and
In order to temporarily stop the needle bar 6 at its uppermost position by stopping the rotation of 14, a needle bar cutoff solenoid 24 is fixed to the mounting plate 23 fixed to the machine frame in the left-right direction. The output shaft 25 is a rotating lever 26 that can be rotated by a pin 34.
And a forked portion 27 at the distal end thereof is engaged with a pin 29 of a slide plate 28. A pair of pins 31 is attached to the support plate 30 fixed to the mounting plate 23, and both pins 31 respectively engage with a pair of long holes 32 formed in the slide plate 28,
The slide plate 28 is restricted by the head of the pin 31 and can move only in the left-right direction. Further, the slide plate 28 and the support plate
A tension spring 33 is stretched on the slide plate 30 and the slide plate 28 is constantly urged rightward.

When the needle bar cutoff solenoid 24 is driven while the sewing machine main shaft 35 is rotating, the rotating lever 26 rotates counterclockwise in FIG. 3 against the spring force of the spring 33, and the slide plate 28 moves to the left. When the needle bar 6 is at the substantially uppermost position, the distal end of the clutch plate 17 comes into contact with the distal end of the slide plate 28, and the rotation of the sewing machine main shaft 35 causes the clutch plate 17 to move as shown in FIG. By rotating to the inoperative position shown by the two-dot chain line, the engagement between the concave portion 12 and the convex portion 18 is released, and the needle bar 6 is held at the uppermost position regardless of the rotation of the sewing machine main shaft 35. When the drive of the needle bar cutoff solenoid 24 is stopped, the slide plate 28 returns to the inoperative position due to the spring force of the spring 33. Therefore, when the phase of the sewing machine main shaft 35 is approximately 30 degrees, the clutch plate is 17 returns to the operating position, the concave portion 12 and the convex portion 18 are engaged again, and the vertical movement of the needle bar 6 is resumed.

FIG. 6 is an enlarged side view of the thread take-up spring device 38 arranged near the lowermost position of the balance 22 in the upper arm 4,
The thread take-up spring device 38 includes a mounting plate 40 fixed to the sewing machine frame 1, a spring holder 44 provided rotatably about a shaft 42 of the mounting plate 40, and a thread take-up spring 46 attached to the spring holder 44. It is composed of And thread take-up spring
The spring holder 44 is urged by a spring (not shown) so that 46 moves from the imaginary line to the solid line, and when the upper thread is picked up by the balance 22, the thread take-up spring 46 is moved by the upper thread to the position of the fantasy line. .

Further, a thread detection sensor 48 including a known light emitting diode and a light receiving diode is attached to the mounting plate 40, and a shutter 50 attached to the spring holder 44 is connected to the light emitting diode in association with the thread pick-up operation of the balance 22. It is configured to cross between the light receiving diode.

Next, the electrical configuration of this embodiment will be described with reference to FIG.

The pattern selection device 52 is configured to generate a pattern code signal corresponding to the selected pattern, and the timing pulse generator 56 detects a predetermined rotation angle of the sewing machine main shaft 35 and generates a high-level timing pulse TP. The reading device 54 is connected to a clock terminal CK of a counter 78 via an AND circuit 80 described later.
It is configured to supply to. The reading device 54 is configured to update the address signal accompanying the pattern code signal of the pattern selecting device 52 every time the timing pulse TP supplied from the timing pulse generating device 56 is input, and to supply it to the storage device 58. The storage device 58 stores a stitch data signal NDS relating to a sewable pattern of the sewing machine, and is configured to generate the stitch data signal NDS according to the supplied address signal. The driving device 60 has a needle swing pulse motor 62, a forward / reverse feed pulse motor 64, a left / right feed pulse motor 66, a needle bar cutoff solenoid according to the stitch data signal NDS.
24 is driven, and a stitch pattern is formed according to the driving of each pulse motor and solenoid. When driving the needle bar cutoff solenoid 24, the driving device 60 outputs a high level needle bar cutoff signal RS to the needle bar cutoff solenoid 24.
And a low-level needle bar cutoff signal RS is supplied to an AND circuit 80 via an inverter circuit 82.

The mechanical structure of the needle swinging device driven by the needle swinging pulse motor 62 and the front-rear and left-right feeding pulse motors 64 and 66 and the mechanical structure of the front-rear and left-right feeding device are described in Japanese Patent Application No. Since the apparatus is the same as the apparatus described in the specification and the drawing of JP-A-52203, its detailed description is omitted.

The start / stop switch 70 is operated to control driving of the sewing machine motor 76, and is configured to supply an operation signal KS to the motor control device 72 in accordance with the operation. The motor control device 72 is configured to supply a motor control signal MCS for controlling driving and stopping of the sewing machine motor 76 to the motor drive device 74 in accordance with the operation signal KS, and to supply a thread breakage detection signal THS from a counter 78 described later. Then, a motor control signal MCS for stopping the sewing machine motor 76 is supplied to the motor driving device 74.

The thread detection sensor 48 detects when the thread take-up spring 46 is moved by the thread take-up operation of the balance 22, and counts a detection signal HS.
It is configured to supply to the reset terminal R of 78.
The counter 78 constitutes a yarn breakage detecting means together with the yarn detection sensor 48 and the timing pulse generator 56, counts the timing pulse TP supplied via the AND circuit 80, and the count value becomes "6". Sometimes yarn break detection signal
The THS is supplied to the motor control device 72 to stop the sewing machine motor 76. The counter 78 is configured to reset its count value to a value of "0" when the detection signal HS is supplied from the thread detection sensor 48 to its reset terminal R. The control means is constituted by the AND circuit 80 and the inverter circuit 82.

The operation of the sewing machine configured as described above will be described below.

When the start / stop switch 70 is operated after the operator selects a desired pattern with the pattern selection device 52, the motor control device 72 drives the motor control signal MCS for driving the sewing machine motor 76 according to the operation signal KS. It is supplied to the device 74, and the motor drive device 74 drives the sewing machine motor 76.

When the sewing machine main shaft 35 is rotated by the driving of the sewing machine motor 76 to generate the timing pulse TP, the reading device 54 and the storage device 58 generate the stitch data signal NDS. Then, the driving device 60 drives each of the pulse motors 62 to 66 and the needle bar cutoff solenoid 24 according to the stitch data signal NDS to form a stitch on the work cloth.

Here, a case will be described in which the drive device 60 continues to generate a low-level needle bar cut-off signal RS for exciting the needle bar cut-off solenoid 24 and causing the needle bar 6 to reciprocate up and down.

Since the high-level signal is supplied to the AND circuit 80 via the inverter circuit 82 while the low-level needle bar cutoff signal RS is generated, the timing pulse TP is supplied to the counter 78 via the AND circuit 80. , The counter 78 increases its count value each time the timing pulse TP is input. However, since the thread take-up spring 46 is moved by the thread take-up operation of the balance 22 and the thread detection sensor 48 generates the detection signal HS to reset the count value of the counter 78, the counter 78 increases and resets the count value. Are repeated alternately, and when the sewing machine normally performs the sewing operation, the count value does not exceed the value of "6".

Here, if a thread break occurs, the thread take-up spring 46 is not moved by the thread take-up operation of the balance 22, so that the thread detection sensor 48
Stops generating the detection signal HS. The counter 78 increases the count value each time the timing pulse TP is input, and supplies a thread breakage detection signal THS to the motor control device 72 when the count value becomes "6". The motor control device 72 provides a motor control signal MCS for stopping the sewing machine motor 76 according to the thread breakage detection signal THS to the motor drive device, and the motor drive device 74 stops the sewing machine motor 76.

 Next, an operation during needle bar interruption will be described.

When the driving device 60 generates a high-level needle bar cutoff signal RS to stop the needle bar 6 at the substantially uppermost position, the needle bar cutoff solenoid 24 is excited, and the needle bar 6 and the balance 22 are moved to the substantially uppermost position. Stop. The stop of the bar needle 6 does not consume the upper thread, and the stop of the balance 22 stops the thread pick-up operation, so that the thread detection sensor 48 stops generating the detection signal HS.
On the other hand, since the low-level signal is supplied to the AND circuit 80 via the inverter circuit 82 by the generation of the high-level needle bar cutoff signal RS, the counter 78 does not increase its count value by the generation of the timing pulse. Accordingly, the sewing machine motor 76 is driven to perform sewing without generating the cut detection signal THS.

[Modifications] The present invention is not limited to the embodiments described in detail above, and various modifications can be made.

For example, in this embodiment, whether or not the thread is broken is detected by detecting the movement of the thread take-up spring moved by the thread take-up operation of the balance.
As in the device described in the publication No. 15092, a friction wheel is provided in which the yarn is hung and rotates according to consumption of the yarn, and by detecting the rotation of the friction wheel, it is detected whether or not the yarn is broken. Is also good.

In addition, in the needle bar blocking device of the present embodiment, the needle bar and the needle bar are configured to be blocked, but the needle bar alone may be configured to be blocked.

[Effects of the Invention] As described in detail above, the present invention invalidates the thread breakage detection operation by the thread breakage detection means while the needle bar is being cut off. It is possible to prevent the detection means from malfunctioning and stopping the sewing machine motor.

[Brief description of the drawings]

1 shows an embodiment of the present invention. FIG. 1 is a block diagram showing an electrical configuration of a sewing machine according to the present embodiment. FIG. 2 is an external front view of the sewing machine. FIG. FIG. 4 is a front view of the needle bar blocking device, FIG. 5 is a sectional view taken along line VV of FIG. 4, and FIG. 6 is a side view of the thread take-up device. In the figure, 6 is a needle bar, 10 is a needle bar blocking device, 35 is a sewing machine spindle,
48 is a thread break sensor, 56 is a timing pulse generator, 76
Is a sewing machine motor, 78 is a counter, 80 is an AND circuit, and 82 is an inverter circuit.

Claims (1)

(57) [Claims] A sewing machine spindle (35) rotatably driven by a sewing machine motor (76), operatively connected to the sewing machine spindle (35), and a sewing machine spindle (3).
A needle bar (6) reciprocating up and down in synchronism with the rotation of 5), a needle bar shutoff means (10) for interrupting the operative connection of the needle bar (6) to the sewing machine main shaft (35); Is provided with a yarn break detecting means (48, 56, 78) for detecting a yarn break by engaging with the yarn and monitoring the movement of the yarn. The yarn break detecting means (48, 56, 78) In the sewing machine for stopping the sewing machine motor (76) when a thread break is detected, while the needle bar (6) is interrupted by the needle bar interrupter (10), the thread break detector (48, Control means (80, 82) for disabling the thread break detection operation of the sewing machine (56, 78), wherein the stopping operation of the sewing machine motor (76) is prohibited while the needle bar (6) is shut off. Sewing machine.