JPS5825994Y2 - Lower thread cutting mechanism in sewing machine - Google Patents

Description

[Detailed Description of the Invention] This invention mainly relates to an improvement of a bobbin thread cutting mechanism for an automatic welt sewing machine.

Conventionally, heaters and sickle blades have been used to cut the bobbin thread in this type of welt sewing machine, but when using the above-mentioned heater, there are many cutting errors due to current fluctuations, and there is a problem with thread waste. etc. have the disadvantage of being easily flammable; on the other hand,
Cutting with a sickle blade has some disadvantages, such as slippage and severe wear of the cutting edge.

In view of these circumstances, the present invention is characterized in that the lower thread having a certain tension is inserted into the knife groove and cut by rotating the knife. To explain in more detail based on the embodiment, 1 is a needle plate on the sewing machine stand, 2, 2 is a needle hole penetrated through the needle plate 1, or 3 is a needle hole 2, which is transparently provided on one side of each needle hole 2. 4 is a female hole extending through the lower thread groove 3.

Furthermore, reference numeral 5 denotes a female rod having a circular cross section that is slidably fitted into the female hole 4, and as shown in FIG. At the same time, the upper end surface of the female rod 5 inserted into the female hole 4 and exposed forms the same surface as the swash plate 1, and the concave groove 5' communicates with the bobbin thread groove 3. This is how it was done.

The lower part of the female rod 5 is connected to a lower drive mechanism, so that the female rod 5 can be freely rotated by a certain amount.

That is, in the figure, 6 is the plywood of the drive mechanism, I is a pedestal that is integrated with the respective female rods 5, 5 in the base plate 6, and a part of which is exposed to the recess 8' of the operating plate 8. Further, 9 is an air cylinder connected to the operation panel 8,
By applying reciprocating motion to the operating plate 8, the female rods 5, 5 are rotated by a certain amount in forward and reverse directions via the pedestal 7 fitted into the recessed portion thereof.

In addition, 10 in the figure indicates a lower thread.

In addition, the groove 5' of the female rod is not limited to the upper end surface, but can also be provided on the lower end surface if necessary, so that when the end corner of the groove on the upper end side is worn out, the female rod can be easily removed. 5 can be used with the top and bottom upside down, thereby doubling its lifespan.

The proposed cutting mechanism according to the diagonal top configuration has the lower thread 10 inserted into the recessed groove 5' of the female rod communicating with the lower thread groove 3 of the throat plate 1, and then when the predetermined sewing is completed, In conjunction with this, an air cylinder 9 that reciprocates once passes through the operating plate 8 to the female rod 5.
, 5 in the forward and reverse directions, each bobbin thread 10, which has been inserted into the groove 5' and is under sufficient tension, is in a twisted state, and the end angle of the female groove 5' is twisted. It can be easily cut.

As mentioned above, according to the proposed cutting mechanism, the bobbin thread is always inserted into the knife groove, so there are no cutting errors, and since the tension of the thread is used, the cutting force is reduced. This has a remarkable effect on improving work efficiency, as there is almost no wear or damage at the end of the concave groove corresponding to the cutting edge.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the bobbin thread cutting mechanism of the present invention, Fig. 2 is a plan view with the top cover of the operating mechanism section removed, and Fig. 3 is an enlarged perspective view showing the concave groove portion of the female rod. It is. In addition, in the figure 1... Throat plate, 2... Needle hole, 3... Lower thread groove, 4... Female hole, 5... Female rod, 6... Base plate, 7
...Pedestal, 8...Operation board, 9...Air cylinder 10...Bobbin thread.

Claims (1)

[Scope of utility model registration request] A needle plate having a lower thread groove formed on one side of the needle hole; The bobbin thread is cut by an automatic sewing machine characterized in that the female rod is fitted into the female hole so that the concave groove communicates with the bobbin thread groove, and the female rod is rotatable by a certain amount via a drive mechanism. mechanism.