JPH10212655A - Material-detecting apparatus for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability as an apparatus for detecting the presence of a string material and enable a maintenance-free state by eliminating a slide-contact part in a signal-transmission path between a detection circuit of the side of a rotary member and a signal generation circuit of the side of a sewing machine main body. SOLUTION: A string raw material 44 delivered from a bobbin 40 supported on a rotary member 34 is successively sewn to a sewing object (sewing cloth 18) under the control of the direction of the bobbin 40 by the rotary motion of the rotary member 34. The sewing machine having the above construction is provided with a detection circuit formed at the side of the rotary member 34 and detecting the exhaustion of the string raw material 44 wound on the bobbin, a signal generation circuit formed at the side of the sewing machine main body and a non-contact signal-transmission means (the primary coil and the secondary coil) enabling the mutual transmission of an electric signal between the detection circuit and the signal generation circuit taking advantage of an electromagnetic induction action. A procedure following the exhaustion of the string raw material 44 on the bobbin 40 is carried out by an electric signal transmitted from the signal generation circuit through the signal transmission means according to the detection with the detection circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine which can sequentially sew a string-like material such as a tape wound on a bobbin to a material to be sewn such as a cloth. The present invention relates to a material detecting device in a sewing machine for detecting exhaustion.

[0002]

2. Description of the Related Art It is generally known to use an embroidery sewing machine as a base as a means for sewing such a string-like material to a workpiece. This embroidery sewing machine is capable of performing main sewing with an upper thread and a lower thread on the basis of the action of a needle bar that reciprocates up and down and a shuttle that is driven to rotate below the sewing table, and a sewn material (embroidered cloth). Is controlled in the X and Y directions based on the embroidery data. Then, the string-shaped material is continuously supplied to a position where the sewing needle attached to the needle bar descends toward the embroidered cloth, and the string-shaped material is sewn to the embroidered cloth by final stitching.

[0003] The string-shaped material is wound around a bobbin, and the bobbin is rotated through a bracket on the outer periphery of a cylindrical rotary member provided to rotate around the axis of the needle bar with respect to the sewing machine body. It is freely supported. The string-shaped material fed from the bobbin is guided below the sewing needle via a guide fixed to the rotating member. In addition, it is necessary to change the supply direction from the periphery of the sewing needle in accordance with the moving direction (X, Y directions) of the embroidered cloth for supplying the cord-like material. Therefore, the rotating member is synchronized with the driving of the sewing machine. The bobbin and the guide are controlled by this.

As the sewing operation by the embroidery sewing machine proceeds, the string-like material is sequentially fed out of the bobbin, and the string-like material wound on the bobbin is eventually supplied.
In this case, sometimes the stitches formed by the upper thread and the lower thread may be formed on the embroidered cloth without noticing that the string material has disappeared from the bobbin. Techniques for avoiding such a situation include, for example, Japanese Utility Model Publication No. 61-902.
There is a material detection device disclosed in Japanese Patent Application Laid-Open Publication No. 1 (1999).

In the technique disclosed in the above publication, an electrode which is switched to an energized state by an operation of a detection member when a string-shaped material wound around a bobbin runs out is provided on a rotating member side supporting the bobbin. It is provided in. On the other hand, a slip ring which is incorporated in an electric circuit leading to the controller and is always in contact with the electrodes is provided on the sewing machine main body side. Therefore, when the electrode on the rotating member side is switched to the energized state, an electric signal is sent to the controller through the slip ring, and based on the signal, a warning that the string-shaped material has run out or a stop of the sewing machine is executed.

[0006]

However, even in the apparatus disclosed in the above publication, during the sewing operation of the embroidery sewing machine, the signal transmission between the rotating member side driven to rotate as described above and the sewing machine main body side is performed. Since it is performed by the contact between the electrode and the slip ring, an erroneous signal may be transmitted due to the poor contact. As a result, the reliability of the device for detecting the presence or absence of the string-like material is poor, and periodic maintenance of the contact portion between the electrode and the slip ring is required.

An object of the present invention is to eliminate the presence or absence of a string-like material by eliminating a sliding contact portion in a signal transmission path between a detection circuit on the rotating member side and a signal generation circuit on the sewing machine main body. Is to improve the reliability as a device for detecting the odor and to make maintenance free.

Another object of the present invention is to reduce the weight and size of the rotating member by eliminating the need for a power supply for the detection circuit.

[0009]

According to the first aspect of the present invention,
A rotation member is provided so as to rotate around the axis of the needle bar with respect to the sewing machine main body, and a cord-like material fed from a bobbin supported by the rotation member is rotated by the rotation of the rotation member in synchronization with the drive of the sewing machine. In the sewing machine of the type in which the bobbin is sequentially sewn to the workpiece while controlling the direction of the bobbin, it is detected that the cord-shaped material provided on the rotating member side and wound on the bobbin has been completely supplied. A detection circuit, a signal generation circuit provided on the sewing machine main body side, and a non-contact type signal transmission unit capable of exchanging electric signals using electromagnetic induction between the detection circuit and the signal generation circuit. Have. An electric signal output from the signal generation circuit through the signal transmission means in accordance with the detection by the detection circuit is set to perform a treatment associated with the absence of the bobbin string material.

According to the first aspect of the present invention, when the string-shaped material wound on the bobbin is completely supplied, the detection circuit on the rotating member side sends a signal to the signal generation circuit on the sewing machine body side. A signal is sent through the contact-type signal transmission means, and based on the output signal from the signal generation circuit, a measure such as a warning that the string material of the bobbin has run out or a stop of the sewing machine is performed. Further, by using a non-contact type signal transmission means for exchanging signals between the detection circuit and the signal generation circuit, the reliability of the detection device is improved, and maintenance-free operation becomes possible.

According to a second aspect of the present invention, in the material detecting device for a sewing machine according to the first aspect, the detection circuit switches an electric resistance value in the circuit when the string-like material of the bobbin is completely supplied. The non-contact signal transmission means is constituted by a primary coil on the signal generation circuit side and a secondary coil on the detection circuit side. As a result, a power source such as a battery is not required for the detection circuit on the rotating member side, and the design on the rotating member side can be made light and compact.

[0012]

Embodiments of the present invention will be described below. FIG. 1 is a perspective view showing a part of a sewing machine (embroidery sewing machine). As shown in this drawing, a sewing head 12 is mounted on a front surface of a frame 10 arranged horizontally. A general embroidery sewing machine is a multi-head sewing machine in which a plurality of sewing heads 12 are arranged at appropriate intervals along the frame 10, but FIG. 1 shows only one sewing head 12 in the multi-head sewing machine. I have. An embroidery frame 16 holding an embroidered cloth 18 is provided below the sewing machine head 12.
Are mounted so as to be able to move along the upper surface of the sewing machine table 14. The embroidery frame 16 is controlled to move in the X and Y directions together with the embroidered cloth 18 by a frame drive mechanism (not shown).

FIG. 2 is a sectional view showing a part of the sewing head 12. Sewing head 1 as shown in this drawing
A needle bar 20 having a sewing needle 22 at a lower end is supported inside the housing 2 so as to reciprocate up and down. This needle bar 2
A drive cylinder 26 is attached to the outer periphery near the lower end of the cylinder 0 so as to be relatively rotatable and vertically movable. The outer periphery of the drive cylinder 26 is guided by the inner periphery of a guide cylinder 24 fixed to the sewing machine head 12. The driving cylinder 26
A support leg 28 is fixed to a lower end of the support leg 2.
A cloth foot 30 is attached to 8. This cloth foot 3
0 has a needle passage hole 3 through which the sewing needle 22 passes.
1 are formed, and the guide 32 of the cord-like material 44 described below is fixed.

A cylindrical rotating member 34 is mounted on the outer periphery of the guide cylinder 24 so as to be rotatable in the direction around the axis of the needle bar 20 and is not movable up and down. The key 36 fixed to the outer periphery of the lower end of the rotating member 34 is provided with a keyway 2 which is formed to be vertically longer than the outer peripheral surface of the support leg 28.
9 is engaged. Therefore, the rotating member 34 and the driving cylinder 26 can rotate integrally. A bobbin bracket 46 that rotatably supports the bobbin 40 around which the string-shaped material 44 is wound is attached to the outer periphery of the lower end of the rotating member 34.

As is clear from FIG. 3, the bobbin bracket 46 is provided with support arms 54, 5 on both ends of a base shaft 48.
5 are attached, and a support shaft 58 is arranged on the free end side of both support arms 54 and 55 in parallel with the base shaft 48. The intermediate portion of the base shaft 48 is attached to the outer periphery of the lower end of the rotating member 34 by bolts 52. The bolt 52 also serves to attach the detector bracket 50 to the base shaft 48.

The free end of one support arm 54 of the bobbin bracket 46 is fixed to one end of the support shaft 58. On the other hand, the other support arm 55
Is rotatable about a mounting portion with the base shaft 48, and its free end is formed in a hook shape and is merely engaged with the other end of the support shaft 58. Therefore, by rotating the support arm 55 as shown by the phantom line in FIG. 3, the hollow shaft 42 of the bobbin 40 can be attached to the support shaft 58 from the open end side thereof. Then, the support arm 55 is returned to the original state. As a result, the bobbin 40 is rotatably supported by the support shaft 58 of the bobbin bracket 46. The string-shaped material 44 wound around the bobbin 40 is passed through the guide 32 as shown in FIG.
Guided between.

The needle bar 20 and the driving cylinder 26 are reciprocated up and down through respective driving mechanisms (not shown) by the rotation of a common sewing machine spindle 13 (FIG. 1) penetrating through the individual sewing heads 12. Is done. The rotating member 34 is driven to rotate about the axis of the needle bar 20 through a power transmission means such as a belt (both not shown) by driving a pulse motor or the like. Since the rotating member 34 and the driving cylinder 26 rotate integrally as described above, the rotation of the rotating member 34 controls the direction of both the bobbin bracket 46 (bobbin 40) and the guide 32.

Then, when sewing data for sewing the string-like material 44 to the embroidered cloth 18 is input to a controller (not shown) of the embroidery sewing machine and the embroidery sewing machine is started, the rotation of the main shaft 13 of the sewing machine is synchronized. Embroidery frame 16
, And the direction of the bobbin 40 and the guide 32 are controlled. Then, the string-like material 44 is moved to the lowering position of the sewing needle 22 by the final sewing based on the action of the sewing needle 22 attached to the needle bar 20 and the shuttle (not shown) arranged below the sewing machine table 14. While being supplied to the embroidery cloth 18 as shown in FIG.

Next, the material detecting apparatus will be described. The bracket 5 fixed to an intermediate portion of the base shaft 48
At 0, a detector 60 shown in FIGS. The detector 60 includes a microswitch 62 and a lever 6
4, and the lever 64 has elasticity in a direction to always contact the outer peripheral surface of the string-shaped material 44 wound around the bobbin 40. Therefore, as the winding diameter of the lever 64 decreases with the supply of the cord-like material 44,
The posture shown by the solid line in FIG. 2 changes to the posture shown by the imaginary line, and the micro switch 62 is pressed when the string material 44 of the bobbin 40 runs out.

FIG. 4 shows an electric circuit of the material detecting device. In this drawing, a detection circuit 6 in the detector 60 is shown.
6 has two resistors 6 together with the microswitch 62.
8, 69 are incorporated, and these are connected to the secondary coil 72. On the other hand, the signal generating circuit 74 on the sewing machine main body side (within the controller) includes a primary coil 70 arranged with a slight gap from the secondary coil 72, and the primary coil 70 A high-frequency current is supplied. Further, the signal generating circuit 74 includes a current detector 78, a comparator 80, a signal generator 82, and the like connected to the power supply circuit of the primary coil 70.

The primary coil 70 and the secondary coil 72
Is a bundle of conductive wires as shown in FIGS. 2 and 3, each having the same diameter. The primary coil 70 is fixed to the lower surface of the flange of the guide tube 24, and the secondary coil 72 is fixed to the upper surface of the upper flange of the rotating member 34. Note that the primary coil 70 and the secondary coil 72 are arranged concentrically with respect to the axis of the needle bar 20 and with the above-mentioned gap in the vertical direction.

Next, the operation of the material detecting device will be described. During operation of the embroidery sewing machine, one of the signal generation circuits 74
A high-frequency current is flowing through the next coil 70. When the sewing of the string-like material 44 to the embroidered cloth 18 progresses and the string-like material 44 wound around the bobbin 40 runs out, the micro switch 62 of the detection circuit 66 is turned off by the lever 64 of the detector 60 from the off state. Switched on. Assuming that the resistance values of the resistors 68 and 69 of the detection circuit 66 are R1 and R2, the resistance value of the detection circuit 66 when the microswitch 62 is off is R1 + R2, and the resistance when the microswitch 62 is on. The value is R1.

When the resistance value of the detection circuit 66 changes, the impedance of the detection circuit 66 also changes. Therefore, the primary coil 70 of the signal generation circuit 74
Is proportional to the resistance value of the detection circuit 66 which is a circuit of the secondary coil 72, and the current value detected by the current detector 78 of the signal generation circuit 74 changes.
That is, it becomes larger. As a result, the output value from the comparator 80 to the signal generator 82 also changes. Based on this, a sewing machine stop signal is transmitted from the signal generator 82, and
A signal is also sent to the display 84 in FIG. 4 to inform the operator that the sewing machine has stopped because the string-shaped material 44 has run out.

As described above, the signal exchange between the detection circuit 66 provided on the rotating member 34 side and the signal generation circuit 74 provided on the sewing machine main body side (in the controller) is performed by an electromagnetic induction action. By using the non-contact type signal transmission means (the primary coil 70 and the secondary coil 72) used, the reliability as the detection device is improved. Further, since a battery or the like is not required for the detection circuit 66 on the side of the rotating member 34, the design of the rotating member 34 can be made light and compact.

As the detector 60, a sensor such as a photoelectric tube switch can be used instead of the micro switch 62 and the lever 64. For example, when the cord-like material 44 is completely supplied and the hollow shaft 42 of the bobbin 40 appears, the photoelectric tube switch is switched. However, in this case, it is necessary to perform a treatment such as making the surface of the hollow shaft 42 capable of reflecting light.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a part of an embroidery sewing machine.

FIG. 2 is a sectional view showing a part of a sewing head.

FIG. 3 is a perspective view showing a bobbin and a bobbin bracket together with a detector.

FIG. 4 is an electric circuit diagram of the material detection device.

[Explanation of symbols]

 Reference Signs List 18 embroidered cloth (sewn material) 20 needle bar 34 rotating member 40 bobbin 44 string-like material 66 detection circuit 74 signal generation circuit

Claims (2)

[Claims] A rotating member is provided so as to rotate around an axis of a needle bar with respect to a sewing machine main body, and a cord-like material fed from a bobbin supported by the rotating member is synchronized with driving of the sewing machine. In a sewing machine of a type in which the bobbin is sequentially sewn to a workpiece while controlling the direction of the bobbin by rotating the rotating member, a string-shaped material provided on the rotating member side and wound around the bobbin is completely supplied. A detection circuit for detecting that a signal has been output, a signal generation circuit provided on the sewing machine main body side, and a non-contact type capable of exchanging electrical signals using electromagnetic induction between the detection circuit and the signal generation circuit. Signal transmission means, and the electric signal output from the signal generation circuit through the signal transmission means in accordance with the detection in the detection circuit, the string material of the bobbin is lost A material detecting device for the sewing machine, wherein the material detecting device is set so as to perform an accompanying treatment. 2. The non-contact type material detecting device according to claim 1, wherein the detecting circuit is configured to switch an electric resistance value in the circuit when the bobbin string-like material is completely supplied. A material detecting device for a sewing machine, wherein the signal transmitting means is constituted by a primary coil on the signal generating circuit side and a secondary coil on the detecting circuit side.