Sewing – Special machines – Pattern controlled or programmed
Reexamination Certificate
2000-08-09
2001-09-18
Nerbun, Peter (Department: 3741)
Sewing
Special machines
Pattern controlled or programmed
C112S273000
Reexamination Certificate
active
06289832
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an apparatus for use in a sewing machine for detecting damage to a covered or uncovered conductive wire. More specifically, the present invention relates to an apparatus for detecting contact of a needle of a sewing machine with a covered or uncovered conductive wire directly or through the covering material, while sewing the wire to an object or article (e.g., a sheet-like material such as a metal foil) with a sewing machine.
As used herein, the term “conductive wire” in “covered conductive wire” and “uncovered conductive wire” includes all linear conductive materials.
BACKGROUND ART
When a covered or uncovered conductive wire is being sewn to an object with embroidery thread by using a sewing machine, it sometimes happens that, owing to some abnormality such as malfunction of the machine, etc., a needle of the sewing machine comes into contact with the conductive wire directly or through the covering material, thereby damaging the conductive wire. The damage leads to insulation failure, conduction failure, breaking or like failures of the covered or uncovered wire. The damaged wire has little or no commercial value.
No apparatus has so far been developed which warns the operator of the damage to a covered or uncovered conductive wire caused by contact with a needle of a sewing machine. Accordingly, the covered or uncovered conductive wire is conventionally inspected for defects after having been sewn to an object or article. Specifically stated, the wire sewn to the object is tested with a conductivity tester for conduction failure, breaking or like failures, and, in the case of a covered conductive wire, visually checked for insulation failure (flaws on the covering material). When the conductive wire to be sewn is a heating wire, defects can be detected by inspecting the wire for anomalous local heat generation. The above inspection methods, however, are troublesome and often fall to detect conduction failure, breaking or insulation failure. The change of detection is particularly low in the inspection of stranded wires which are comprised of a plurality of fine wires.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an apparatus for detecting contact of a needle of a sewing machine with a covered or uncovered conductive wire, while sewing the wire to an object or article with a sewing machine.
The present invention provides a damage detection apparatus for use in a sewing machine comprising a bobbin having a conductive wire wound thereon and a sewing mechanism including a metal needle, which sews the conductive wire drawn from the bobbin to an object with a thread by means of the metal needle, the apparatus comprising: a terminal to be electrically connected to part of the conductive wire, and an indicator electrically connected to both of the terminal and the metal needle and arranged to indicate the occurrence of contact of the metal needle with the conductive wire.
The apparatus may further comprise: a hollow conductive sleeve having a first longitudinal bore and fitted in a second longitudinal bore provided to the bobbin, and a conductive axle inserted through the first longitudinal bore of the sleeve and rotatably supporting the sleeve and electrically connected to the sleeve, wherein the terminal is provided on the conductive sleeve and is electrically connected to the indicator through the conductive sleeve and the conductive axle.
The apparatus may further comprise an operation control unit that stops the operation of the sewing machine upon occurrence of contact of the metal needle with the conductive wire.
The term “sewing machine” as used herein includes zigzag sawing machines that form zigzag stitches, automatic sewing machines and like sewing devices.
According to the present invention, when a covered or uncovered conductive wire is being sewn to an object or article with the sewing machine, the indicator does not operate while the sewing machine works normally, i.e., while the needle is not in contact with the conductive wire, either directly or through the covering material.
When the needle of the sewing machine comes into contact with the conductive wire directly or through the covering material owing to some abnormality, the circuit associated with the indicator is closed via a terminal connected to the conductive wire and the metal needle of the sewing machine, whereby the indicator operates.
In the above manner, the apparatus of the invention can detect and indicate contact of the needle of the sewing machine with the conductive wire, while sewing the wire to the object or article with the sewing machine.
According to the present invention, damage to a conductive wire caused by contact with a needle can be detected from the reading on the indicator. Further, the damage can be detected in real time, so that suitable measures can be taken more efficiently than in detection by inspection after sewing. That is, when damage to the conductive wire is detected in real time, the damaged portion of the wire can be easily located so that the damage inducing factor can be immediately checked to take preventive actions. For example, if irreparable damage such as breaking is caused to the conductive wire during sewing, a proper measure, for example, the interruption of the sewing operation, can be carried out before the sewing of the wire is complete. This prevents a situation such that the whole length of the wire is sewn to the object or article despite occurrence of damage and the finished product has to be discarded, thereby diminishing the loss of materials and reducing costs.
The apparatus of the present invention can be so constructed as to transmit a signal to the control system of the sewing machine to automatically stop the sewing machine upon closure of the circuit of the indicator, i.e., upon contact of the needle with the conductive wire. The automatic control of the sewing machine is particularly advantageous for use in a multi-head sewing machine that performs simultaneous sewing of a plurality of objects. That is, when the wire is damaged, the head causing the damage can be identified in real time, from the circuit action of the indicator. It is possible to stop only the head causing the damage while continuing operation of the other heads, to thereby minimize the work loss of the multi-head sewing machine as a whole and improve the throughput.
REFERENCES:
patent: 3998173 (1976-12-01), Williamson et al.
patent: 4703705 (1987-11-01), Wiley
patent: 57-10801 (1982-01-01), None
patent: 3-190080 (1991-08-01), None
Knobbe Martens Olson & Bear LLP
Kotobuki Industrial Co, Ltd.
Nerbun Peter
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