JPH0113400B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a needle position detection device provided in a zigzag stitch sewing machine in order to stop the sewing machine at a predetermined position of the needle.

Conventionally, the sewing machine stops at the predetermined position of the needle,
A device is already in use that decelerates a sewing machine that is rotating at high speed to a low speed, maintains a state in which the rotation of the sewing machine is synchronized with the cycle of this low-speed drive, detects the stop position, and stops the machine at a fixed position. However, this device stopped regardless of the left or right position of the needle.

In a zigzag stitch sewing machine, stopping the sewing machine at a predetermined lateral position of the needle is required, for example, in the following cases. In other words, in order to change the sewing direction with the needle stuck in, it is necessary to change the orientation of the workpiece (corners may not be sewn at a given position), or when sewing workpieces together. (If the needle is not in a fixed position, the finish of the workpiece will vary), or when cutting the thread at the end of sewing, or when taking out the workpiece (the needle must be held at the upper stop position immediately after the lower stop position). required).

Conventionally, a device for stopping a zigzag sewing machine at a predetermined needle position has been proposed in Japanese Patent Publication No. 46-10142. In other words, the lateral pricking position of the needle is controlled by a control switch controlled by a permanent magnet attached to a device for generating zigzag movement (swing rod), or by a synchronization device that rotates 1/2 turn with respect to the upper shaft. This will stop the sewing machine at the lower needle position depending on whether it is on the left or right side.

However, in this conventional device, from the center to the left,
Alternatively, since only two stopping positions can be obtained from the center to the right, it can be used for ordinary zigzag stitches and straight stitches, but for 3-point zigzag and 4-point zigzag stitches, it is not possible to always stop at the specified position. It was difficult. In this case, it is possible to use a control switch, but it must be adjusted each time the swing width changes, and the mechanism is complicated due to the large number of wiring and components.

The present invention attempts to solve the above-mentioned drawbacks of the conventional technology by replacing it with a position detection plate that is compatible with various types of zigzag stitches. In order to make the stopping position accurate (to match the stopping position and the timing of the brake), a speed generator for speed detection, one magnet, and two
In a needle position detection device equipped with two magnetic sensing elements and two position detection plates that operate the magnetic sensing elements by blocking magnetism, a predetermined lower stop position and upper stop position are obtained according to the number of stitches of the zigzag stitch. For this purpose, the sewing machine is equipped with a reduction gear and a detection plate drive gear whose drive is transmitted via a rotor fixed to the upper shaft of the sewing machine, and one or more blades on both sides of the collar fixed on the detection plate drive gear. A vane-type position detection plate with
The vane-type position detection plate engages with a protrusion provided on the collar so as not to rotate relative to the collar, and decelerates the rotation of the vane-type position detection plate relative to the rotation of the sewing machine. The present invention aims to provide a needle position detection device for a sewing machine that can detect and stop at a predetermined position in various types of zigzag stitches by having a position detection plate that can be easily replaced depending on the type of zigzag stitch. be.

In the present invention, the position detection plate rotates at a reduced speed through a reduction gear with respect to the rotation of the sewing machine, so the position detection plate rotates at 3 points and 4 points.
It is sufficient to use a position detection plate corresponding to each of the dot zigzag, regular zigzag, and straight stitch sewing machines, and it is easy to replace them. Furthermore, since there are fewer components, the device is compact and lightweight, making it easy to handle, and the stopping accuracy is no different from that of conventional detection devices.
Moreover, it has the advantage that it can be easily attached to a conventional sewing machine.

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B show an embodiment of the sewing state of a workpiece by the apparatus of the present invention, in which a workpiece 1, for example, a pocket, is sewn in a four-point zigzag pattern, also serving as decorative stitching. When sewing with stitch 53, if you stop the sewing machine at the corner of the pocket, the so-called predetermined stop position 2, at the bottom stop position near the bottom dead center of the needle (Fig. 1 A), the needle will remain stuck. Even if you change the direction of the pocket (Figure 1 B), you can always start sewing from the corner. However, if the needle stops at the lower stop position of any intermediate sewing position, the corner will remain unstitched. According to the present invention, even if the sewing machine is stopped halfway, it always stops at the end of the pocket as shown at 2' in FIG. 1B, making it easy to check the seam allowance and control the sewing direction.

FIG. 2 is a front view showing the operating state of the apparatus according to the embodiment of the present invention. A fixed position stop motor 4 is attached to the lower side of the table 3, and the motor 4 is connected to the needle n.
When the foot pedal 5 attached to the lower part of the table leg 56 is depressed, the sewing machine is rotated at high speed by the motor control device 7 via the connecting rod 6. 1
Give high speed rotation to 1.

Next, when the foot pedal 5 is returned to the neutral position, the needle position detection device 14 attached to the upper shaft 12 of the sewing machine 11 detects the lower stop position of the needle n near the bottom dead center.
The sewing machine 11 is stopped at the lower stop position by the fixed position stop motor 4 via the motor control device.

When the foot pedal 5 is further depressed in the opposite direction, the needle position detection device 14 moves the sewing machine 11 to the top stop position of the needle n near the top dead center of the thread take-up (rotates 180 degrees and stops). In FIG. 2, 8 is a motor main shaft, 9 is a motor pulley, 10 is a belt, 13 is a flywheel, 15 is a lead wire, and 16 is a needle bar.

Next, Figure 3 shows the needle position detection device 1 in Figure 2.
FIG. 4 is an exploded perspective view of the device of FIG. 3. FIG. In FIGS. 3 and 4, the rotor 17 is attached to the upper shaft 12 of the sewing machine with a rotor fixing screw 18 (timing of the stop position is adjusted by this screw 18), and rotates together with the sewing machine 11. Further, the rotor 17 is connected to the detection device body 1.
9 and is rotatably held by a ball bearing 20.

Reference numeral 23 denotes a speed generator, which controls the drive speed of the motor 4 by converting the rotation of a speed generator magnet 25 fixed to the rotor 17 into voltage, and this is a conventionally known device. A rotor shaft 28 is press-fitted into the rotor 17 and rotates in the same manner.

This rotor shaft 28 is a gear bearing that is press-fitted into a ball bearing holder 31 attached to the detection device body 19 together with a switch bracket 30 using a ball bearing holder attachment screw 29 by a drive gear 28' formed on the shaft 28. It is rotatably held at 32.

In addition, a resin reduction gear A formed by integral molding
33, the rotation of the sewing machine 11 is transmitted to the reduction gear B33', and the rotation of the sewing machine 11 is further transmitted to the rotor shaft 28 by a thrust stop washer 34 and a retaining ring 35 to the detection plate drive gear which is loosely held. It is transmitted at a reduced speed.

36 is a detection plate drive gear, and detection plate fixing screw 37
Two single blade type detection plates (a lower stop 39a and an upper stop 39b) are fixed with the collar 38 in between. The blades of the upper stopper 39b are fixed at a position with a rotation angle delayed by 30 degrees with respect to the blade of the lower stopper 39a by the protrusions A38' and B38''.

Moreover, the magnetic sensing elements A42a and B42b that detect the position of this detection plate are connected to the position detection magnet 4.
The elements 42 are arranged in the axial direction on both sides of the element 42.
When the blade of the detection plate rotates and reaches between a and 42b and the magnet 43, the magnetism is cut off and the sewing machine is stopped.

Therefore, in the case of the 4-point zigzag stitch 53 (Fig. 5 AA), the number of stitches to be sewn in the horizontal direction is 6 in one cycle, so if you first set the right needle to the lower stop position,
Be sure to position it at the right needle down stop position. Similarly, the upper stop position also stops immediately after that. In addition, 21 in the figure
is a washer, 22 is a thrust washer, 24 is a speed generator mounting screw, 26 is a lead wire for the speed generator, 30 is a switch bracket, 40 is an insulating seat mounting screw, 41 is an insulating seat, 44 is a printed wiring board,
45 is a lead wire for position detection, 46 is a cover, 57
2 is a thrust washer, and 27 is a connector.

Note that the lower lateral stopping position of the needle n can be set at any position of the four-point zigzag stitch 53 using the rotor fixing screw 18, so that even if the zigzag width is changed, it can be handled without readjusting. Further, the upper stop position also stops immediately after that in accordance with the above.

In the above example, the rotation of the detection plate was decelerated to 1/6 to perform 4-point zigzag stitches, but it is also possible to reduce the pressure to 1/4 of the rotation of the detection plate and perform 3-point zigzag stitches. can.

Next, Fig. 5 shows examples of various position detection plates and various stitches corresponding to the detection plates when the rotation of the detection plate is decelerated to 1/6.
9, B indicates a three-blade position detection plate 49, and C indicates a six-blade position detection plate 50. Further, FIG. 5 AA shows a four-point zigzag stitch 53, BB shows a regular zigzag stitch 54, and CC shows a straight stitch 55.

Figure 6 shows examples of various position detection plates when the rotation of the detection plate is decelerated to 1/4, and various stitches corresponding to the detection plates, and A is the same single-blade type position detection as in Figure 5A. 6A shows a three-point zigzag stitch 56, FIG. 6B shows a two-blade position detection plate 51, C shows a four-blade position detection plate 52, and FIG. 6BB shows the plate 39. Normal zigzag stitch 54, CC is straight stitch 5
5 is shown.

As described above in detail, the present invention provides a needle position detection device for a sewing machine, which includes a reduction gear and a detection plate drive gear to which drive is transmitted via a rotor fixed to an upper shaft of the sewing machine, and a detection plate drive gear. A vane-shaped position detecting plate having one or more blades is disposed on both sides of the collar fixed above, and the vane-shaped position detecting plate engages with a protrusion provided on the collar and moves to the collar. 3-point, 4-point zigzag, normal zigzag,
By using a vane-type position detection plate that corresponds to each type of linear zigzag, etc., the lower stop position of the sewing machine needle can be determined.
Even for straight stitches or various types of zigzag stitches, when a stop command is issued, the lower stop position of the needle can be set at the end of the workpiece. In addition, the vane-type position detection plate engages with a protrusion of a collar fixed on the detection plate drive gear, so that it does not rotate relative to the collar, so it prevents the detection plate from shifting. Accurate position detection can be obtained.

[Brief explanation of drawings]

1A and 1B are explanatory diagrams showing a state in which a pocket is sewn by the device of the present invention, FIG. 2 is a front view showing a state in which the device according to an embodiment of the present invention is used, and FIG. 4 is an exploded perspective view of the needle position detection device; FIGS. 5A, B, C and 6A, B, C are front views showing various vane-shaped position detection plates; Figure 5 AA, BB, CC and Figure 6
AA, BB, and CC are explanatory diagrams showing various types of zigzag stitches. Explanation of the main parts of the diagram, n... Needle, 1... Workpiece, 4... Fixed position stop motor, 7... Motor control device, 11... Sewing machine, 14... Needle position detection device, 23... Speed Generator, 25...Speed generator magnet, 33...Reduction gear A, 33'...Reduction gear B, 36...Detection plate drive gear, 39...1
Blade type position detection plate, 42a...Magnetic sensing element A, 42b...Magnetic sensing element B, 43...Position detection magnet, 53...4-point zigzag stitch, 54...
...Normal zigzag stitch, 55...Straight zigzag stitch, 56...
...3-point zigzag stitch.

Claims (1)

[Claims] 1. The fixed position stop motor, which has the function of stopping the needle of the sewing machine in a fixed position, detects rotational fluctuations of the sewing machine so as to drive the sewing machine at a predetermined low speed, and uses an output voltage to control the fixed position stop motor. Speed generator with feedback via control device,
A two-position detection function comprising one position detection magnet that indicates the stop position of the sewing machine, two magnetic sensing elements, and a position detection plate that rotates with the sewing machine and blocks two magnetisms arranged in the axial direction. A needle position detection device for a sewing machine equipped with a needle position detection device includes a reduction gear and a detection plate drive gear to which drive is transmitted via a rotor fixed to the upper shaft of the sewing machine, and a needle position detection device for a sewing machine equipped with A vane-type position detection plate having one or more blades is disposed on both sides, and the vane-type position detection plate engages with a protrusion provided on the collar so as not to rotate relative to the collar. By decelerating the rotation of the blade-type position detection plate relative to the rotation of the sewing machine and replacing it with a blade-type position detection plate that is compatible with various types of zigzag stitches and straight stitches,
1. A needle position detection device for a sewing machine, characterized in that the lower stop position of the needle of the sewing machine can be selected and stopped at any of the sticking positions of the needle forming the stitch.