JPH0616617Y2 - Spark discharge type thread trimmer of sewing machine - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial field of application The present invention relates to a thread cutting mechanism of a sewing machine, and in particular, it has a small and simple mechanism with a small number of parts and is capable of reliably cutting two threads. The present invention relates to a spark discharge type thread trimming device of a sewing machine that can be used.

(B) Conventional technology Conventionally, as a thread cutting mechanism of a sewing machine, a cutting blade that advances or retreats or swings with respect to a thread to be cut is provided (Jitsuko Sho 60-
40213) is generally used.

Further, as a thread cutting mechanism of a sewing machine used for a special purpose, as shown in FIG. 7, a nichrome wire 50 is always energized and heated, and a thread 52 drawn out from a sewing machine needle 51 is burned out by a heat fusing type. The one (Jitsuko 60-37109) is also used.

(C) Problems to be solved by the invention That is, in the mechanical structure like the former, the number of parts is large and the structure is complicated, and since each part is a precision part requiring high precision, the production cost is high. However, in the latter case of the heat fusing type, a detachment drive structure for connecting and disconnecting the constantly radiating nichrome wire to the yarn must be constructed. However, there is a problem that the structure of the portion becomes large and it is difficult to incorporate it in the sewing machine, and it can be used only for a special purpose.

The present invention has been made in view of the above problems, and an object thereof is to provide a spark discharge type thread trimming device for a sewing machine, which has a simple structure and is excellent in operability.

(D) Means for solving the problem The spark discharge type thread trimming mechanism of the sewing machine according to the present invention is provided by sandwiching the upper thread and the lower thread passing section of the sewing machine, and is made of a high-voltage insulator. A separate electrode 2 composed of a pair of conductive electrodes having a tip structure and having a tip structure, and a conductive electrode covered by a shell made of a high-voltage insulator except a smooth opposing surface. It is composed of an arc discharge part, which is sandwiched and has a smooth opposite surface, and a Monmon electrode facing the pointed structure, and a high voltage generator for applying a high voltage current to the arc discharge part. Is the gist.

(E) Action Since the discharge shape of the arc discharge generated in the arc discharge part is controlled to be flat, the upper thread and the lower thread of the sewing machine passing between the electrodes can be reliably burned. Further, since the arc discharge part has a flat and small structure with no mechanically movable parts, it can be easily incorporated into a small sewing machine.

(F) Embodiment An embodiment of a spark discharge type thread cutting device for a sewing machine according to the present invention will be described below with reference to FIGS. 1 to 4.

The mechanism of the present invention constitutes the arc discharge part 1 near the retracted position of the sewing machine needle, through which the upper thread a and the lower thread b of the sewing machine pass, and the separate electrode 2 and the conmon electrode are sandwiched so as to sandwich the sewing machine passage. It is composed of 3 parts. The separate electrode 2 is formed by sandwiching electrodes 6 and 6 made of a pair of conductors by an inner shell body 4 and an outer shell body 5 made of a high-voltage insulator, and the tips of both electrodes 6 and 6 on the near side. A projecting tip structure 7 is provided, and the tip structure 7 is covered by the edges of the shells 4 and 5.

Further, the monmon electrode 3 is an inner shell 8 made of a high voltage insulator.
And an outer shell 9 sandwiching an electrode 10 made of a conductive material, and a smooth facing surface 11 facing the pointed structure 7 is covered with the edges of the shells 8 and 9.

The arc discharge unit 1 is connected to a high voltage generator built in the sewing machine main body. As the high voltage generator, for example, a known leakage transformer 12 as shown in FIG. 1 is used.
Is preferred. The output voltage of the pair of secondary side windings 14, 14 wound around the core 13 of the leakage transformer 12 is configured to be equal pressure, and one pole side is connected to both electrodes 6, 6 of the separate electrode 2, and The other electrode side is connected to the electrode 10 of the Common electrode 3, and is configured so that a potential difference between the electrodes 6 and 6 hardly occurs.

The leakage transformer 12 applies a control voltage 16 to the primary side winding 15 when arc discharge is required, and another electrode facing the electrodes 6 and 6 of the arc discharge part 1 by a high voltage on the secondary side. An arc discharge will be generated during 10 seconds.

The arc discharge R is applied to the separate electrode 2 arranged in parallel in the width direction with respect to the smooth facing surface 11 of the electrode 10 of the Monmon electrode 3.
Since the tip structures 7 of both electrodes 6 and 6 of
As shown in the figure, the discharge between the tip structure 7 and the facing surface 11 becomes flat, and the upper thread a and the lower thread b passing between the electrodes 6 and 10 are burned.

(G) Effect of the device As described above, the spark discharge type thread trimming device of the sewing machine according to the present invention controls the discharge shape of the arc discharge generated in the arc discharge part to be flat, so that it passes between the electrodes. The two threads (upper thread and lower thread) can be simultaneously and reliably burned.

Further, in the above-mentioned configuration of the present invention, since the structure of the arc discharge part is flat and small, it can be easily incorporated into the sewing machine. In addition, since the device of the present invention has no mechanically movable parts, it has the characteristics that it can be expected to have a long service life. Therefore, the practical effect after the implementation of the present invention is extremely large.

[Brief description of drawings]

FIG. 1 is a circuit explanatory view of the entire device showing a spark discharge type thread cutting mechanism of a sewing machine according to the present invention, and FIG. 2 shows a structure of a flat arc generating electrode of the same device. FIG. 3, FIG. 3, FIG. 4 and FIG. 5 are sectional views taken along line III-III, line IV-IV, line V-V in FIG. 2, respectively, and FIG. FIG. 7 is a perspective view of a main part of a conventional heat-melting type thread cutting mechanism. 1-arc discharge part, 2-separate electrode 3-conmon electrode, 6,10-electrode 7-tip structure, 11-smooth facing surface 12-leakage transformer 14-secondary side winding, 15-primary side winding a ~ Upper thread, b ~ Lower thread

Claims (2)

[Scope of utility model registration request] 1. A sewing machine, which is provided by sandwiching a passing portion of an upper thread and a lower thread, and is covered by a shell body made of a high-voltage insulating material excluding a tip portion,
The separate electrode composed of a pair of conductive electrodes having a pointed tip and a shell made of a high voltage insulating material cover and sandwich the conductive electrode except for the smooth facing surface, and the smooth facing surface is covered by A spark discharge type thread trimming device for a sewing machine, which comprises an arc discharge part composed of a conmon electrode facing a pointed structure and a high voltage generator for applying a high voltage current to the arc discharge part. 2. The spark discharge type thread trimmer for a sewing machine according to claim 1, wherein the high voltage generator is a leakage transformer.