JPS61206484A - Yarn cutter of ring stitch sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a sewing thread cutting device for a sewing machine, and relates to a sewing thread cutting device for a sewing machine having multiple needles such as a single needle chain stitch sewing machine or a covered needle chain stitch sewing machine. Used for cutting empty threads on sewing machines, etc.

(Prior art) As a conventional device of this kind, there is a device in which empty yarn is held between comb teeth and then cut with a scalpel (US Pat. No. 3,025,811).
etc. are known.

(Problems to be Solved by the Invention) In recent years, sewing threads made of thermoplastic synthetic resin fibers have come into widespread use, and when cut with a scalpel, the cut portion frays, and when burned out with a hot wire, etc. There was an inconvenience that the thread burned and the end of the thread became carbonized and clumped together.

The present invention is intended to prevent such inconveniences from occurring when cutting the empty thread.

[Structure of the invention]

(Means for Solving the Problems) As a means for solving the above-mentioned problems, in the present invention, a thread cutting punch is provided behind the needle drop in the sewing machine feed direction, and is actuated by an external force and heated by an external electric current.

Then, a female member was fixed at a position below the bed surface corresponding to the punch, and a punch holder that was movable up and down with a spring and had a thread holding surface was physically combined with the knife.

The thread holding surface of the punch holder is configured to be located slightly above the blade tip of the knife under normal conditions.

(Function) After one sewing item is sewn, when the empty thread part passes through the thread holding part of the punch holder, the sewing machine is stopped and the punch is pushed down by external force. (At this time, the punch is heated by an attached heater that is supplied with electricity from the outside.) Therefore, the lower surface of the punch presses the empty yarn against the yarn holding surface.

Then, as the punch descends further, the punch holder is pushed down against the spring, and the lower surface of the punch comes into contact with the blade of the fixed scalpel to cut the thread.

Both cut ends of the cut thread are fused together by the heat of the punch.

(Example) In FIGS. 1 and 2, 1 is an arm of a chain stitch sewing machine, 2 is a bed, 3 is a needle bar, and 4 is a presser foot.

Reference numeral 5 denotes a bracket, which is fixed to the back attachment surface of the arm 1 with screws 6, to which an air cylinder 7 is attached, and to the cylinder shaft 8 of which an operating member 9 is attached.

10 is a guide member, 11 is a punch, and the two are connected with a screw 13 with a mica-protected heater 12 interposed between them.

Thus, the guide member 10 is connected to the guide pin 14.14.
°, said actuating member 9 via spring 15.15'
The guide part 9°, 9” fits into the locking nut 16.16°
is maintained by Reference numeral 17 denotes a conductive wire, which is drawn out from the end of the heater 12 and is energized from an external wire 20 connected to a terminal 19 of the terminal board 18.

Reference numeral 21 denotes a female attachment member, which is attached to the bed 2 with screws 21'' and is provided with retaining plates 22 and 22'.

Reference numeral 23 denotes a punch holder, which is an angle member having thread holding surfaces 23' and 23'', and guide pins 25.25° are fixed at both ends with screws 27.27''.

Therefore, this guide pin 25.25' is a guide spring 26.26 whose spring thickness is weaker than that of the spring 15.15°.
7 and screws 28.28'' into the retaining plate 22.
22'.

Reference numeral 24 denotes a knife fixed to the member 21, and the cutting edge of the knife 24 in normal state is attached to the thread holding surface 23 of the punch 23.
．． The entire assembly is adjusted so that it is located approximately 1 to 2 fl below 23°.

〔Effect of the invention〕

In order to solve the above technical problem, heater (hot wire)
It is also conceivable to install a thread cutting knife and a thread cutting knife in parallel and press the thread from above (Jikko Sho 5l-47496), or to press a heated punch with a heater to the lower knife to cut the thread. Both methods involve heat bonding and cutting,
Since this is done almost simultaneously, there is a risk that the thread may be cut before the fusion progresses, or that the thread may be burned out by heat before being cut by the scalpel. In the present invention, the punch holder (empty yarn holder) is positioned slightly above the blade surface of the scalpel, and one yarn is pressed with a heated punch to perform the yarn fusing operation, and then the knife disconnected by. In addition, since the punch presses both sides of the knife, the end of the thread at the end of sewing and the end of the thread at the beginning of sewing are always fused to prevent fraying, resulting in a reliable and beautiful cut. Can be cut. Furthermore, when this device has multiple needles such as a multi-needle quilt sewing machine, if the punch and female part sides are extended as they are and the length is made to accommodate the multiple needles, it can be It is extremely efficient and can be used for knitted threads, fusing and cutting 8 threads at the same time with one punch, making it ideal for use in automatic sewing, etc.

[Brief explanation of drawings]

FIG. 1 is a side view of a sewing machine equipped with a thread cutting device of the present invention, viewed from the face plate side, and FIG. 2 is an exploded view of the structure of the device shown in the first figure. 7... Air cylinder, 9... Operating member.

Claims (1)

[Claims] A thread cutting punch that is activated by an external force and heated by external electricity is provided behind the needle drop in the sewing machine feed direction, and a female member is fixed at a position corresponding to the punch below the bed surface. A hollow thread cutting device for a chain stitch sewing machine, in which a punch holder having a spring-movable thread holding surface is integrally combined with the scalpel, and the thread holding surface is normally positioned slightly above the blade edge of the scalpel.