JPH0328960B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an automatic thread cutting device for selectively cutting only the upper thread or both the upper and lower threads in an embroidery sewing machine. be.

[Conventional technology and its problems]

In recent years, needle thread and
It is equipped with a device that cuts the bobbin thread at the same time to improve the efficiency of sewing or embroidery. However, in an embroidery sewing machine, the cut upper thread and lower thread are free, so the upper thread often slips out of the needle hole at the beginning of sewing. In addition, on the back side of the embroidery cloth, both the upper and lower threads are cut at the same time each time the color thread changes, so the threads are not tight at the beginning of sewing, resulting in poor embroidery results, and even worse. On the back side of the fabric, the ends of the bobbin thread cut off each time the color changes remain, making the back side of the fabric visually appealing.

The present invention selectively cuts the upper thread or both upper and lower threads, and when changing color threads, cuts only the upper thread and continues embroidering without cutting the bobbin thread. Improve the initial thread tightness,
To finish embroidery beautifully and to simultaneously cut both upper and lower threads only when embroidery is completed so that no thread ends remain when finished on the back side of cloth.

[Means to solve the problem]

The present invention has been made in order to achieve the above object, and a hook for hooking the upper thread is swingably provided in the front direction of the inner hook, facing the inner hook, and adjacent to this hook, the hook for hooking the upper thread is provided. The cutter for cutting is swingably installed,
At a position opposite to this needle thread hooking, feeding and cutting device, a device is provided on the lower surface of the throat plate to hold the thread end after the bobbin thread has been fed out to a required length and cut. A cutter for cutting is integrated in a V-shape, and a lever is provided on the lower surface of the throat plate so as to be able to swing freely, and the lever is located closer to the needle hole in the throat plate than the cutter, and the lower thread is moved in cooperation with this lever on the lower surface of the end of the throat plate. The gist of the present invention is to provide a holder for holding the ends, and to selectively cut the upper thread and both the upper and lower threads, and to cut each thread by letting out only the required length.

〔Example〕

The present invention will be explained below based on embodiments shown in the drawings.

In the figure, reference numeral 1 denotes a lower body block of the sewing machine, inside which a hook shaft 2 is rotatably disposed as shown in the figure, and this shaft is rotatably driven by a drive source. In the case of a single-rotary hook, the needle rotates once per movement of the needle, and in the case of a rotary hook, the hook rotates twice.The outer hook 3 is fixed to the tip of the hook shaft 2, and rotates together with the hook shaft 2. Then, fit the inner hook 4 into the outer hook 3. A bobbin on which bobbin thread is wound is attached to and detached from the inner hook 4 via a bobbin case.The inner hook is locked by a hook stopper 5 fixed to the lower body block, and the outer hook rotates together with the hook shaft. The inner pot is always supported so that it remains stationary even when moving.

On one side of the outer hook 3, a hook 6 for hooking the needle thread is attached to the outside of one side of the outer hook 3. The needle thread hook 6 is attached to the outside of one side of the outer hook 3 through a shaft 7, as shown in FIGS. 2 and 3. The hook 6 is provided in the lower body block so as to be swingable, and the upper end of the hook 6 is arranged to abut the upper front position of the inner hook or to be inserted into a notch in the upper front surface of the bobbin case housed in the inner hook. Claw 6a
The tip of a rod 8 (also a wire) is fixed to the lower end of the hook 6, and the base end of the rod 8 is connected to a drive source 9 such as a rotary solenoid provided on the block 1. The drive source 9 is operated just before cutting the upper thread to connect the hook 6 via the rod 8.
The claw 6a at the tip of the hook projects forward from the standby position in front of the inner hook, and is brought into contact with or inserted into the front of the inner hook or the bobbin case, so that it is fed out by the rotation of the outer hook. A part of the needle thread is hooked with a claw, and a predetermined length longer than that of the outer hook alone is fed out by swinging the hook.

Further, a cutter 10 for cutting the needle thread is provided on the same side as the hook 6 and at a position above the hook 6. The proximal end of this cutter 10 is
1, the cutter 10 is pivotably attached to the block 1, and its tip side is bent into a beak shape and has a sharp point, forming a blade 10a on this side surface.
The tip of the rod 12 (or wire) connected to a drive source 13 such as a rotary solenoid provided in the hook is engaged with the tip of the rod 12 (or wire), and one side of the upper thread hooked on the claw of the hook is cut by operating this drive source. Therefore, this cutter 10 is normally in a standby position, and after the needle thread is hooked by the claw of the hook, it swings and accurately cuts only one side of the needle thread with a beak-shaped blade. It is.

Note that the hook for hooking the upper thread and the drive source for operating the cutter are provided on the back side of the lower main body block, but they may be located on either of the lower main body blocks.
It can be installed in front of the block or at an appropriate location on the sewing machine frame.

A throat plate 16 is provided above the outer hook, that is, on the top surface of the lower main body block, in the same manner as in conventional sewing machines. A lower thread feeding, cutting and holding device as shown in FIGS. 1 and 2 is provided on the lower surface of the throat plate 16. This machine is shown in plan view with the throat plate removed in FIGS. 1 and 4. A needle hole 16a through which the needle is inserted is bored in the center of the needle plate 16, and the lower thread is hooked on one side of the lower surface of the needle hole 16a, and the lever 15 for feeding out the required length and the cutter 14 for cutting are integrated in a V-shaped shape. At this time, the lever 15 for feeding is made to be closer to the needle hole than the cutter 14, and when the lever swings, the V-shaped integrated shaft 17 is placed so that the lever contacts the bobbin thread before the cutter. Installed so that it can swing freely. The lever 15 is in the standby position at the needle hole 16.
In order to avoid this and to make it easy for the upper thread to be caught, an arc-shaped cutout surface 15a is formed on the side surface of the lever, and the cutter 14 has a blade 1 on one side of its tip.
4a, stack the cutter and lever one above the other with the base end thereof facing upward, and
This overlapping portion is swingably provided on the throat plate 16 by a shaft, for example, a screw. When the upper thread is hooked, the lever is set in advance, and when the upper thread is cut by the cutter 14, the lever is set so that only the required length is let out. Make a V shape so that they touch each other. The lever and the cutter are fixed separately to the shaft 17 with a screw 18, and the screw 18 and the shaft 17 form a required V-shape.
Then, a long hole 14b is bored in a part of this cutter 14, and the tip of the rod 19 is inserted into this long hole 14 with a pin P.
The cutter 14 and the lever 15 are pivoted about the shaft 17 via the rod 19 by operating a drive source 20 such as a rotary solenoid provided at the base end of the rod, and the upper thread is rotated. Performs feeding and cutting. The needle thread is cut by the cutter 14 and the fixed cutter 21, similar to scissors. This fixed type cutter 21 is fixed to the lower surface of the throat plate via the shaft 17 and another set screw 23, and is provided opposite to the forward swinging position of the lever 15, so that the cutter 14 swings upward. Cut the thread. Also, the thread end of the cut needle thread is held immediately before or at the same time as cutting. This is accomplished by providing a leaf spring 22 on the lower surface of the front end of the throat plate, and sometimes attaching felt, a female fastener, a rubber plate, or other elastic material to the leaf spring 22, and then attaching the above-mentioned elastic material between the leaf spring 22 and the lower surface of the throat plate. By inserting the lever 15,
The yarn end is held between the lever 15 and the leaf spring. When the lever 15 is inserted between the leaf spring and the throat plate, the needle thread is cut by the cutters 14 and 21. Further, an elastic material may be attached to the side surface of the lever 15 in the same manner as the leaf spring, and the cut thread end may be held between the two elastic materials.

Next, the operation of the present invention will be explained.

When sequentially embroidering with different color threads, only the upper thread is cut and the lower thread is not cut, but when the embroidery is completed, both the upper and lower threads are cut at the same time. The cutting of only the upper thread and the simultaneous cutting of both the upper and lower threads are selectively performed depending on the work. When cutting only the upper thread, use cutter 1.
0 swings, and the cutter 14 and lever 15 remain stationary. Next, the case where both the upper and lower threads are cut at the same time will be explained.

When the embroidery is completed and the needle is still moving up and down before the sewing machine stops, the needle thread feeding hook 6 in the standby position shown in Fig. 4A is moved to the rod 12 by operating the drive source.
When the claw 6a of the hook moves forward and comes into contact with the front surface of the bobbin case, the upper thread, which is wound around the outer hook and fed out in a loop by the rotation of the hook, is pulled by the hook 6a. Hung and tensioned. While maintaining this state, the cutter 10 is then swung in the direction of the arrow from the solid line position in FIG. 1A, and when it becomes as shown in FIG. Cut the thread on the cutter side.
Next, the bobbin thread is let out and cut. This is done when the cutter 14 and lever 15 are swung from the solid line position A in Figure 4 to the position C in the figure. The bobbin thread is reliably caught in the notch 15a and let out by swinging the lever. When the cutter that swings after this lever comes to the position of the fixed cutter as shown in figure D, the lower thread is cut into the blade 14a of this cutter 14.
Then, the lower thread is cut like scissors by the blade 21a of the fixing cutter 21, and the thread end of the lower thread is forcibly inserted and held by a lever inserted between the leaf spring 22 and the throat plate. After cutting the bobbin thread, the cutter 14 and the feeding lever 15 return to their original positions.

〔Effect of the invention〕

According to the present invention, an upper thread feeding and cutting device consisting of a hook and a cutter which slides opposite to the front surface of the inner hook and comes into contact with the front surface of the bobbin case to feed and cut the upper thread to a required length from the outer hook is provided on the block side. A lower thread feeding and cutting device is provided on one side of the outer hook, and a lower thread feeding and cutting device is provided on the opposite side of the outer hook and below the throat plate. so that it comes into contact with the bobbin thread first,
Because it swings, you can first hook the bobbin thread with a lever, let it out, and then cut it with a scissor-type cutter, ensuring reliable cutting and holding the end of the bobbin thread as it is. Therefore, when changing color threads, it is possible to selectively cut only the upper thread, or when embroidery is complete, to cut both the upper and lower threads at the same time, which has the advantage of tighter threads, beautiful embroidery, and a beautiful finish on the back of the fabric. .

[Brief explanation of drawings]

Fig. 1 is a plan view of the main parts, Fig. 2 is a front view of the same, Fig. 3 is a side view of the same, Fig. 4 is an explanatory diagram of the operation during thread cutting, Fig. 5 is a schematic plan view of the sewing machine bed, and Fig. 6 is a schematic plan view of the sewing machine bed. The figure is a front view of the same. 1 is the lower body block, 2 is the hook shaft, 3 is the outer hook, 4
is the inner hook, 5 is the hook stopper, 6 is the hook for feeding the upper thread,
7 is a shaft, 8, 12, 19 are rods (links, wires, etc.), 9, 13, 20 are drive sources, 10, 14,
21 is the cutter, 15 is the lever, 16 is the throat plate, 1
1 and 17 are shafts, 21 is a fixing cutter, and 23 is a leaf spring.

Claims (1)

[Claims] 1. A hook for hooking the needle thread is swingably provided in the front direction of the inner hook, facing the inner hook, and a cutter for cutting the needle thread is swingably provided adjacent to the hook,
At a position opposite to this needle thread hooking, feeding and cutting device, a device is provided on the lower surface of the throat plate to hold the thread end after the bobbin thread has been fed out to a required length and cut. A cutter for cutting is integrated in a V-shape, and a lever is provided on the lower surface of the throat plate so as to be able to swing freely, and the lever is located closer to the needle hole in the throat plate than the cutter, and the lower thread is moved in cooperation with this lever on the lower surface of the end of the throat plate. An automatic thread cutting device for an embroidery sewing machine, characterized in that a holder is provided to hold the ends, and the needle thread and both the upper and lower threads are selectively cut, and each thread is fed out only to a required length. .