JPH0610951Y2 - Sewing condition detector for sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention relates to a sewing condition detecting device for a sewing machine.

For more details, see the sewing machine sewing machine that can detect that the upper thread is cut during the sewing operation of the sewing machine and the thread take-up spring that guides the upper thread does not swing normally during the sewing operation. The present invention relates to a condition detecting device.

(Prior Art) A conventional sewing condition detecting device of a sewing machine is disclosed in, for example, Japanese Patent Publication No. 46-
No. 5 disclosed in Japanese Patent No. 36701 and attached to the present specification
As shown in the figure, a balance 5 is pivotally attached to the sewing machine main body A so as to be swingable, and the upper thread 3 is wound on the needle of the sewing machine, and the upper thread 3 is fed from the bobbin winding 31 to the above-mentioned balance 5. 3, a thread take-up spring 4a that applies tension to the upper thread 3 so as to eliminate the slack of the upper thread 3, and a sensor 8a that detects the reciprocating position of the thread take-up spring 4a. And
Only one end of the thread take-up spring 4a is pivotally attached to a part of the tension adjusting portion, an upper thread catching portion 42a is formed in a central portion connected to the one end, and the other end 42b is swung along with the swing of the balance 5. Is configured.

(Problems to be Solved by the Invention) When the structure of the conventional sewing tone detecting device for a sewing machine is applied to an industrial sewing machine, the following problems occur.
That is, productivity is emphasized in industrial sewing machines, and the balance of the balance 5 is adjusted by operating at high speed and by adjusting the tension of the upper thread 3 to be high so as to be able to sew thick materials. The load due to the severe position movement of the needle thread 3 accompanying the remarkable swinging action acts on the thread take-up spring 4a. Therefore, the thread take-up spring 4a swings following the positional movement of the needle thread 3 moving at high speed. Since the thread take-up spring 4a is in a so-called fluffy state in which only one end is swingably held, the thread take-up spring 4a
A force acting in a direction perpendicular to the swing direction of the thread take-up spring 4a is generated with the first bent portion P1 forming the upper thread catching portion 42a at the central portion P3 of a as a fulcrum, or the swing direction of the thread take-up spring 4a. When is switched from one to the other, an overrun phenomenon due to inertia may occur with the second bent portion P2 as a fulcrum. Therefore, the other end 42b of the thread take-up spring 4a oscillates on a trajectory deviated from the position where the sensor 8a can detect and generates an erroneous signal, or the first and second bending of the thread take-up spring 4a due to long-term use. Excessive stress may be concentrated on the portions P1 and P2, and metal fatigue may occur to deform or damage the upper thread catching portion 42a of the thread take-up spring 4a.

Furthermore, the sensor 8a for detecting the swing position of the thread take-up spring 4a and the other end 42b which is a detected portion of the thread take-up spring 4a.
Since the sensor 8a is installed within the swing range of the other end 42b of the thread take-up spring 4a, the stroke of the thread take-up spring 4a can be determined by the type of thread or the cloth to be sewn. When changing depending on the type, it was necessary to readjust the installation position of the sensor 8a.

The main object of the present invention is to provide a sewing condition detecting device for a sewing machine, which can cope with high-speed operation of the sewing machine.

[Structure of the Invention] (Means for Solving Problems) The present invention provides the following means in order to solve the above conventional problems.

That is, the sewing machine tension detecting device of the present invention is mounted on the mounting board, the thread take-up spring shaft fixed to the mounting board, mounted on the thread take-up spring shaft, and guided by the guide hole of the balance. And a thread take-up spring for applying tension to the thread, the thread take-up spring being guided coaxially with the thread take-up spring shaft and having one end locked to the thread take-up spring shaft. A coil portion, an upper thread catching portion projecting from the coil portion in a circumferential direction, a ring portion formed on the other end side of the upper thread catching portion and coaxially guided by the thread take-up spring shaft, Between the thread catching portion and the ring portion,
A protruding portion protruding from the ring portion to the opposite side of the thread catching portion, the protruding portion includes a detected portion detected by a sensor, and the sensor is configured to detect the thread take-up at the top dead center of the balance. The swing position of the detected portion of the spring is set as a detection position.

With this structure, the thread take-up spring according to the present invention can swing the needle thread catching portion while being coaxially attached to the thread take-up spring shaft at both ends of the needle thread catching portion. Thus, even if the upper thread catching portion swings at a high speed, undue stress does not act on the bent portion forming the upper thread catching portion.
Moreover, the stress is balanced so that the stress does not concentrate on one point. Therefore, the upper thread catching portion is not deformed or damaged, and the durability can be increased.

Furthermore, according to the configuration of the present invention, the swing position of the thread take-up spring is stable, and the installation position of the sensor is set with the swing position of the detected portion of the thread take-up spring at the top dead center of the balance as the detection position. be able to. Therefore, even if the stroke of the thread take-up spring is changed according to the type of thread or the type of cloth, the position of the detected portion of the thread take-up spring at the dead center of the balance becomes constant.
There is no waste of adjusting the installation position of the sensor that detects the detected portion each time the stroke of the thread take-up spring is changed.

The sewing condition detecting device for a sewing machine of the present invention comprises a mounting substrate, a thread take-up spring shaft, and a thread take-up spring as constituent elements.

The mounting substrate is fixed to the sewing machine main body with a thread take-up spring shaft and a thread take-up spring, which will be described later, attached.

The thread take-up spring shaft is fixed to the mounting substrate while the thread take-up spring is coaxially supported.

The thread take-up spring applies tension to the upper thread, which moves from the bobbin to the sewing machine needle, as necessary. That is, the upper thread is fed to the swinging balance, and the slack of the upper thread moving between the upper thread and the balance is absorbed to apply tension to the upper thread in a timely manner. The thread take-up spring is composed of a coil portion, a needle thread hooking portion, and a ring portion. The coil portion is attached to the outer circumference of the thread take-up spring shaft 2 with one end thereof being locked to a part of the thread take-up spring shaft 2. The upper thread catching portion projects from the coil portion in the circumferential direction, guides the upper thread to the balance, and contacts the upper thread,
Moreover, the tension is applied to the upper thread in a timely manner by the urging force of the entire thread take-up spring in response to the repeated tension and slack of the upper thread caused by the swing of the balance. The ring portion is formed on the other end side of the needle thread engaging portion and is loosely fitted on the thread take-up spring shaft. The ring portion is attached to the thread take-up spring shaft while being fitted into the collar locking portion. The thread take-up spring is mounted on the thread take-up spring shaft with the coil section arranged on one side of the mounting board and the ring section arranged on the other side of the mounting board. Further, with the mounting substrate interposed between the coil portion and the ring portion, the mounting spring is integrally mounted on the mounting substrate together with the first guide plate and the second guide plate by the tightening nut.

The thread take-up spring may have a projecting portion formed between the upper thread catching portion and the ring portion, the projecting portion projecting to the opposite side of the upper thread catching portion from the ring portion, and the projecting portion may have a detected portion detected by a sensor. In this case, if the upper thread guided by the upper thread catching section causes an abnormal situation such as cutting during the sewing operation,
The fluctuation of the tension of the upper thread acting on the upper thread catching section interrupts the swing of the thread take-up spring and the sensor detects an abnormal position of the detected section, whereby the driving of the sewing machine can be stopped. Furthermore, even if the swing stroke of the thread take-up spring is changed according to the type of needle thread and the thickness of the cloth to be sewn, the position of the sensor that detects the detected portion does not have to be adjusted. I'm done.

(Operation) According to the sewing machine tension detecting device of the present invention, the thread take-up spring is guided coaxially with the thread take-up spring shaft, and one end of which is stopped by the thread take-up spring shaft, and the coil portion in the circumferential direction. Since the upper thread catching portion and the ring portion formed on the other end side of the upper thread catching portion and guided coaxially with the thread take-up spring shaft are provided, the upper thread catching portion has a guided movement. Become. In addition, when the upper thread, which is guided by the upper thread catching section and swings to the balance, moves at a high speed, the thread take-up spring can reliably follow the swing operation of the balance and the movement of the upper thread. Even if the dynamic operation is fast, the stress applied to the needle thread hooking portion is balanced and is not concentrated at one point, so that the needle thread hooking portion is not deformed or damaged. Furthermore, since both ends of the upper thread catching portion are coaxially held and swing on the thread take-up spring shaft, a very stable swinging state can be obtained. As a result, the range of movement of the detected part that is held by the protruding part that protrudes on the opposite side of the upper thread hooking part is also stable, and when the upper thread is cut or entangled, it is necessary to stop the sewing machine operation. Can immediately detect the abnormal movement of the detected portion and stop the driving of the sewing machine.

In addition, the thread take-up spring can set the type of thread by setting the detected part of the protruding part that protrudes to the opposite side of the thread catching part to the detection position where the swing position corresponding to the top dead center of the balance is detected by the sensor. Even when the stroke of the thread take-up spring is changed in consideration of conditions such as the cloth thickness and the like, it is not necessary to adjust the sensor position for detecting the detected portion.

(Embodiment) FIG. 1 is a view showing an embodiment of a sewing condition detecting device for a sewing machine of the present invention,
A description will be given based on FIGS. 2, 3, and 4.

The sewing machine tension detecting device of the embodiment has a mounting substrate 1, a thread take-up spring shaft 2, and a thread take-up spring 4 as constituent elements.

The mounting substrate 1 includes a thread take-up spring shaft 2 and a thread take-up spring 4 which will be described later.
Attaching part A of sewing machine main body A shown in FIG.
It is fixed at 1.

The thread take-up spring shaft 2 is mounted on the mounting substrate 1 with the thread take-up spring 4, the first guide plate 11, the second guide plate 12, the collar 13 and the like being coaxially mounted, and the tip of the thread take-up spring shaft 2 is mounted. Screw part 2
The mounting substrate 1 by the tightening nut 14 screwed to
Fixed to. The first guide plate 11 is combined with the second guide plate 12 to guide the needle thread 3 described later.
The first guide plate 11 and the second guide plate 12 are provided with stroke adjusting slots 112 and 122 for adjusting the swing stroke of the thread take-up spring 4. Within the range of the long holes 112 and 122 for adjusting the stroke, the first guide plate 11 and the second guide plate 11
A fixing screw 15 is screwed to the mounting substrate 1 so that the position of the guide plate 11 can be fixed, and is fixed to the long holes 112 and 122 for adjusting the stroke to fix the first guide plate 11 and the second guide plate 12. Has been. Further, the first guide plate 11 has a thread take-up spring stopper 113 that engages with a part of the thread take-up spring 4.
Are formed.

The thread take-up spring 4 is composed of a coil portion 41, a needle thread hooking portion 42, and a ring portion 43. The coil portion 41 is guided coaxially with the thread take-up spring shaft 2 and has one end 410 inserted and locked in the locking hole 210 of the thread take-up spring shaft 2. The upper thread catching portion 42 guides the upper thread 3 and projects from the coil portion 41 in the circumferential direction. The ring portion 43 is the thread catching portion 42.
Is formed on the other end side of and is guided coaxially with the thread take-up spring shaft 2.

Further, the thread take-up spring 4 is fitted on the thread take-up spring shaft 2 with the coil portion 41 arranged on one side 1a of the mounting board 1 and the ring portion 43 arranged on the other side 1b of the mounting board 1. The coil portion 41 is inserted into the coil portion 41 on one side 1a of the mounting substrate 1.
One end 410 is inserted and locked in the locking hole 210 of the thread take-up spring shaft. The ring portion 43 penetrates the mounting hole 101 of the mounting substrate 1 in the order of the first guide plate 11, the second guide plate 12, and the collar 13 with the collar 13 mounted on the other side 1b of the mounting substrate 1. The thread take-up spring shaft 2 is mounted, and the tightening nut 14 is screwed to the tip thread portion 21 of the thread take-up spring shaft 2. The mounting substrate 1 to which the thread take-up spring shaft 2 and the thread take-up spring 4 are thus fixed is fixed to the mounting portion A1 of the sewing machine main body A.

The upper thread 3 from the bobbin 31 rotatably mounted on the upper part of the sewing machine main body A is locked to the upper thread catching section 42 of the rear thread take-up spring 4 guided by the first guide plate 11 and the second guide plate 12. It The upper thread 3 is further provided in front of the sewing machine main body A in such a manner that a tip guide hole 51 of a balance 5, which is swingably mounted, a guide hole 61 of a reciprocating rod 6, and a sewing needle 7 mounted on the reciprocating rod 6. The needle hole 71 and the like are inserted. In this state, the sewing machine operates and shifts to the sewing process.

Further, the upper substrate 3 is guided by the first guide plate 11 and the second guide plate 12 while the mounting substrate 1 with the thread take-up spring shaft 2 and the thread take-up spring 4 attached thereto is fixed to the sewing machine main body A. In addition, the thread take-up spring 4 is engaged with the upper thread catching portion 42 of the thread take-up spring 4, guided by the guide hole 51 of the balance 5, and loaded in the guide hole 71 of the sewing machine needle 7. The sensor 8 is attached to the sewing machine main body A with the swinging position of the detecting portion 45 attached to the projecting portion 44 of the thread take-up spring 4 as the detection reference position at the position (shown in FIGS. 3 and 4). The sensor 8 has a cutout portion 83 in which the detecting portion 45 mounted on the protruding portion 44 of the thread take-up spring 4 swings, and has a light source 82 and a light-sensing element positioned at both ends of the detecting portion 45 with a constant space. And a base portion 81 having a reference numeral 84. The base 81 is a screw 8
5 is attached to the sewing machine main body A.

According to the configuration of this embodiment, the balance 5 swings in synchronization with the reciprocating movement of the sewing machine needle 7 as the sewing machine operates.
As the balance 5 swings, the tension between the first guide plate 11 and the second guide plate 12 and the upper thread 3 of the balance 5 is maintained, and the upper thread 3 moves as the scale 5 swings. 2, the thread take-up spring 4 swings, and the upper thread catching portion 42 moves the upper thread 3 to the upper thread 3 guided by the first guide plate 11 and the second guide plate 12.
It is smoothly fed to the sewing machine needle 7 via.

Further, the thread take-up spring 4 swings around the thread take-up spring shaft 2, and the projecting portion having the upper thread catching portion 42 and the detecting portion 45 moves within the swinging range shown in FIGS. In addition, the detection unit 45
Is detected electrically and periodically when the detection unit 45 reaches a position where the light source 82 and the light sensing element 83 of the sensor 8 are cut off according to the operation cycle of the sewing machine. Here, when the upper thread 3 is cut for some reason, the tension acting on the upper thread engaging portion 42 of the upper thread 3 is lost, and the balance 5 is at the top dead center position. However, the detection portion 45 of the thread take-up spring 4 is not located at the detection position of the sensor 8. This makes it possible to electrically detect an abnormality and stop the operation of the sewing machine.

[Effects of the Invention] According to the sewing tone detecting device of the sewing machine of the present invention, the coil portion 41 and the ring portion 43, which are the end portions of the thread take-up spring 4, are coaxially held by the thread take-up spring shaft 2, and Since the thread catching portion 42 is swingably held with the coil portion 41 and the ring portion 43 as two pivotal fulcrums, the rigidity of the needle thread catching portion 42 is increased and, for example, high speed swinging of 6000 rpm is performed. Can withstand enough. That is, even if the tension of the upper thread 3 constantly acts and the stress acts on the upper thread engaging portion 42, the thread take-up spring 4
Is axially supported at both ends around the upper thread catching portion 42, so that the stress related to the upper thread of the upper thread catching portion 42 is balanced and stable, and abnormal stress may act on a part of the upper thread catching portion 42. Absent. As a result, the thread take-up spring 4 has excellent durability.

Furthermore, the protrusion 4 of the thread take-up spring 4 is located at the top dead center of the balance 5.
If the swing position of the detected portion 45 provided on the sewing machine 4 is set as the detection position and the sensor 8 is fixed to the sewing machine main body A, the type of the upper thread 3 or the thickness of the cloth to be sewn can be changed. The first guide plate 11 and the second guide plate 12 are adjusted by a fixing screw 15 to adjust the tension of the needle thread 3, and are rotated within the range of the stroke adjusting slots 112 and 122. It is not necessary to move the position of the sensor device 8 each time when the swing stroke is adjusted.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a main part of a sewing condition detecting device of a sewing machine of the present invention, FIG. 2 is a front view showing a state in which the main part in FIG. 1 is assembled and attached to a sewing machine main body, and FIG. 2 is a side view, and FIG. 4 is an operation diagram in FIG. FIG. 5 is an assembly perspective view showing a conventional structure. 1 ... Mounting substrate, 2 ... Thread take-up spring shaft 3 ... Upper thread, 4 ... Thread take-up spring 41 ... Coil section, 42 ... Upper thread catch section 43 ... Ring section, 44 ... Projection section 45: Detected part, 410: One end

Claims (1)

[Scope of utility model registration request] 1. A mounting base plate, a thread take-up spring shaft fixed to the mounting base plate, and a thread that is mounted on the thread take-up spring shaft and comes into contact with a thread guided in a guide hole of a balance. A thread take-up spring for applying tension to the thread take-up spring, the thread take-up spring being guided coaxially with the thread take-up spring shaft and having one end locked to the thread take-up spring shaft; A needle thread hooking portion projecting in the circumferential direction, a ring portion formed on the other end side of the needle thread hooking portion and coaxially guided by the thread take-up spring shaft, the needle thread hooking portion and the ring portion. Between
A protruding portion protruding from the ring portion to the opposite side of the thread catching portion, the protruding portion includes a detected portion detected by a sensor, and the sensor is configured to detect the thread take-up at the top dead center of the balance. A sewing-tone detecting device for a sewing machine, wherein the swing position of the detected portion of the spring is set as a detection position.