JPS6112063Y2 - - Google Patents

Description

[Detailed description of the invention] This invention allows an embroidery sewing machine to cut only the upper thread, only the lower thread, or both the upper and lower threads at the same time, and to cut the thread end to the minimum necessary level so that the end of the thread does not come out from the needle when cutting the upper thread. This invention relates to a thread end feeding and cutting device that automatically cuts the thread in a state in which the thread is fed out.

Conventionally, sewing machines for sewing or embroidery are equipped with a device for automatically cutting the upper thread and lower thread to improve the efficiency of sewing or embroidery work. However, when the needle thread is cut, the thread take-up is raised and the needle thread is let out, but the needle thread that is passed through the cloth, passes through the needle hole, and reaches the thread take-up is tensioned by the rise of the thread take-up. Since the needle thread is cut at a certain position, a force acting on the needle thread to cause it to instantly contract is often applied, and the thread end of a slippery needle thread such as one used for embroidery often slips out of the needle hole. This thread removal greatly affects the next work.

In order to prevent this, if more thread ends than necessary are fed out and cut, the excess thread ends must be cut off after the embroidery is completed.

In view of this, the present invention prevents the thread end from slipping out of the needle hole even when using slippery embroidery thread, allows the next sewing to be performed, and cuts the thread end without letting out more thread end than necessary. This is what I am trying to do.
Although the present invention will be described as an embroidery sewing machine, it can also be applied to ordinary sewing machines (household and industrial), and will be described below based on the illustrated embodiment.

In the figure, 1 is a lower body block of an embroidery sewing machine that rotatably supports a hook that houses a bobbin in which the bobbin thread is wound and a bobbin case in which the bobbin is inserted. 2 is held horizontally so as to protrude from the front surface of the lower body block, and is driven by a desired driving source so that the needle rotates once (one-turn hook) or twice (two-turn hook) per one stroke of the needle. At the tip of this hook shaft 2 is an outer hook 3.
The inner hook 4 is fitted into the outer hook 3 so as to rotate together with the hook shaft, and the inner hook rotation stopper lever 5 fixed to the lower main body block 1 is attached to the inner hook 4.
A part of the bobbin is locked to support the inner hook so that it does not rotate even when the outer hook is rotated, and a bobbin case containing the above-mentioned bobbin is provided inside the inner hook so that it can be freely attached and detached. , which is configured like a normal sewing machine. Further, the lower main body block 1 is provided with a lower thread feeding device 6 and an upper thread hooking device 7 slidably on one side in front of the outer hook, but these are a part of the lower main body block or attached to this. It shall be installed on the vertically installed bracket B. This lower thread feeding device 6 is a lever type that is swingably supported on a part of the lower main body block or bracket B with a shaft 6b orthogonal to the hook axis, and is bent and provided at the tip of this lever 6a. It consists of a lower thread hooking piece 6c positioned above the hook. The upper thread hooking device 7 has a hook portion which is brought into contact with the front surface of the hook at the tip of a sliding rod 8 which passes through the lower main body block or bracket B and is slidably supported parallel to the hook axis. A lever 7a with a lever 7b protruding from the lever 7a is provided, and a locking piece 9 is fixed to this sliding rod 8.
One side edge of the lever 6a of the bobbin thread hooking device is brought into contact with the lever 6a, and the sliding rod 8 is bent when a force is applied to push it in, and this pushing force is released. A spring S ₄ is sometimes provided to return it to its original position. This spring _S4 acts in the longitudinal direction of the sliding rod, while the spring _S3 provided on the lever 7a acts when the lever 7a is rotated and the rotational direction is restored.

Both devices, i.e., a solenoid is provided at the rear end of the sliding rod 8 and a solenoid is provided at the bottom of the lever 6a so that the lever can be swung. It shall be driven by The lever 6a is also provided with a restoring spring _S2 .

In addition, a cutting device 1 for cutting the sewing thread fed out to a predetermined length is located above the hook and below the top plate 11.
0 is set. This is a rod 1 equipped with a cutter at the tip as shown in the figure, or a cutter 10a necessary for cutting sewing thread such as nichrome wire.
The rear end of 0b can be slid in and out using a solenoid and a return spring _S1 , and this cutting device 10 is synchronized with the lower thread feeding device 6, the needle thread hooking device 7, or either one of them. It is driven.

When cutting the thread, the lower end of the lever is pushed or pulled in the direction of the arrow by the operation of a solenoid or the like, so that the lower thread feeding device 6 is slid in the front direction of the outer hook so as to be separated from the surface of the outer hook. Thereby, the bobbin thread is hooked on the tip of the bobbin thread hooking piece 6c, and the bobbin thread is let out so that the thread end has the minimum necessary length to prevent the thread from coming off in the next process. In addition, the hook portion 7b at the tip of the needle thread hooking device 7 is formed in a hook shape so that the thread passed through the needle by rotation of the outer hook can be hooked on the looped portion along the outside of the outer hook. This hook portion 7b is slid from a standby position away from the inner hook so as to come into contact with the side surface of the inner hook during thread cutting.

Therefore, if it is desired to cut both the upper and lower threads at the same time, the bobbin thread pay-out device is first driven while the needle is rising. When the lever 6a swings in the direction of the arrow in FIG. 2 using a solenoid or the like, the hooking piece 6 at the upper end
When the bobbin thread is hooked at point c and the hook piece 6c is separated from the outer hook, it is fed out in a loop shape and one end edge of the lever 6a slides through the engagement piece 9 due to the swinging of the lever 6a. As the rod 8 is pushed down, the lever 7a of the needle thread pay-out device rotates and comes into contact with the outer hook. Then, the needle descends and is inserted into the hook, and then when the needle begins to rise, a portion of the upper thread is inserted into the needle hole at the hook portion 7b which becomes the upper thread hook of the rotating outer hook. After the needle is hooked, the needle rises further. When this needle reaches the highest position, the balance (not shown) is still rising and has not yet reached the highest position. When the thread take-up further rises from this state, the needle thread is normally fed out from the spinning wheel that has wound the needle thread. When the outer hook further rotates, a portion of the upper thread hooked on the hook portion of the outer hook forms a loop along the outer surface of the outer hook.
At this time, the hook portion of the needle thread hooking device slides from the standby position and runs closely against the side surface of the inner hook, so the loop portion of the needle thread can be easily hooked onto the hook portion by rotating the outer hook. When the hook portion is released, the force of the solenoid or the like in the direction of the arrow is released, and the hook portion is swung by the force of the spring in a direction away from the inner pot and attempts to return to its original position. In this state, both the upper and lower threads are cut by the forward action of the cutter provided on the back of the throat plate, and the sewing machine stops. Therefore, tension is applied to the upper thread due to the lifting of the thread take-up, but even if the thread is instantly contracted at the same time as the thread is cut, the upper thread hooking lever is still paying out more than the amount fed out by the thread take-up in a loop. Even if the needle thread is slippery, the length of the thread end is set to the minimum necessary length to prevent the thread from slipping out, so the thread end will not slip out of the needle hole and the next sewing can be carried out smoothly. Moreover, there is no need to cut off the excess thread end after embroidery. When cutting only the bobbin thread, it is sufficient to drive only the bobbin thread hooking device.

According to the present invention, the upper thread, which is inserted into the needle and fed in a loop along the outer hook, is placed at a lower position of the bobbin thread pay-out device and is slidable or pivotable in the front and back direction, and is attached to the side surface of the inner hook. After the upper thread is hooked with a hook that approaches and separates, and the upper thread is let out beyond the normal let-out by the thread take-up, the lower thread is brought out by the cutting device together with the lower thread let out by the lower thread unreeling device, and is brought close to the upper thread hooking device below the throat plate. Since the needle is cut at the desired position, the length from the needle to the end of the thread is the minimum necessary length so that it will not come off during the next embroidery, so the thread will not come off the needle and the next sewing will be smooth. Moreover, since the excess thread end does not protrude after the thread is completed, the trouble of cutting it off is saved.Furthermore, the solenoid that is the driving source for the upper thread hooking device and the bobbin thread feeding device is located at the rear of the lower main body block, so the block can be easily removed. It has the advantage of being easy to install even though it is small.

[Brief explanation of the drawing]

Figure 1 is a side view showing only the main parts of the lower part of the sewing machine, Figure 2 is a perspective view of the lower part of the sewing machine seen from the front.
FIG. 3 is an explanatory diagram of the operation shown in FIG. 2. 1... Lower body block, 2... Hook shaft, 3... Outer hook, 4... Inner hook, 5... Inner hook turning stop lever, 6...
...Lower thread feeding device, 7...Needle thread hooking device, 8...Sliding rod, 9...Engagement piece, 10...Cutting device, B...Block, _S1 to _S4 ...Spring.

Claims (1)

[Scope of utility model registration request] Placed above the outer pot and in the horizontal direction of the outer pot,
A lever-type bobbin thread feeding device is swingably installed so that the bobbin thread drawn out from the bobbin is drawn out in a loop shape from the outer hook when the thread is cut, and the device is located on the outside of the outer hook and is spaced apart from the outer hook. An upper thread hooking device having a hook portion at the tip of a rod that can slide in the direction is provided along the outer hook at one side of the outer hook at the bottom of the sewing machine main body, and the above-mentioned lever type The upper thread hooking device is swung in front of the lower main body block by a drive device provided on the lower main body block, and the rod of the upper thread hooking device is made slidable by the drive device,
In addition, a retaining piece provided on the rod is engaged with a part of the bobbin thread hooking device so that one or both of the upper and lower thread hooking devices can be selectively driven, and each thread hooking device is equipped with a spring for restoring the thread hooking device. The cutter of the cutting device is provided below the needle plate so that the bobbin thread upper thread is paid out to the minimum necessary extent and the thread end does not come out of the needle hole, and is opposite to the bobbin thread hooking piece. A device for feeding and cutting thread ends in embroidery sewing machines.