JPS5812034B2 - How to derive the bobbin thread for double chainstitch on a sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for leading out a bobbin thread for double chainstitch in a sewing machine, and more particularly, to a method for leading out a bobbin thread for double chainstitch in a sewing machine, and in particular, a bobbin thread that is inserted into an inner hook of a conventional lockstitch sewing machine and cooperates with the inner hook and needle. This invention relates to a method for easily leading out the bobbin thread for forming the double chainstitch from a supply source to the right side through a cauldron when performing double chainstitch by the action of the parts.

Household sewing machines currently on the market are usually equipped with a single chainstitch device that uses a single needle thread, which allows them to selectively perform lockstitch and single chainstitch. ing.

However, the single chainstitch has problems such as the strength of the seam, the degree of elasticity, and the light emitted when the thread breaks.Recently, research has been conducted on a double chainstitch device that can be attached to a home sewing machine. has been started and several ideas have already been proposed.

However, with this type of double chainstitch device, in addition to the device itself, there is a problem in the way the bobbin thread is drawn out, that is, the way the bobbin thread is drawn out from the supply source through the cauldron to the right side, which makes it difficult for ordinary sewing machine users. However, making it possible to easily extract the bobbin thread is a major problem in practical implementation.

The present invention has been made in view of the above circumstances, and its purpose is to provide a method by which a general sewing machine user can very easily lead the bobbin thread to the right side when performing double chainstitching. That's true.

An embodiment of the present invention will be described below with reference to the drawings.
2 is a needle plate placed on the bed 1; 3 is a needle that passes through a needle hole 2a formed in the needle plate and moves up and down; 4 is a cauldron disposed below the throat plate 2; Reference numeral 5 denotes a known inner hook rotatably supported by the large hook, which is rotated reciprocally around one axis in synchronization with the up and down movement of the needle 3 by a driver 6, and works in cooperation with the needle to perform lock stitching. A seam can be formed.

As is well known, the inner hook 5 has an upper thread T.
a thread ring catching beak 5a for catching the upper thread ring; a throat part 5b continuing inward in the radial direction; a heel part 5c located approximately 180 degrees apart from the throat part; A bobbin case (with a front fin 5d for guiding the opening and a bobbin holding the bobbin thread for forming a lockstitch in the inner hook 5)
A support shaft 5e for removably attaching the
etc.

Reference numeral 7 denotes a double chainstitch insert body which is inserted into the inner hook 5 in place of the bobbin and bobbin case so as to move together with the inner hook, and as shown in FIG. have similar shapes.

That is, the insertion body 7 includes a substantially disc-shaped front flange 8 whose front surface is formed as a smooth thread sliding surface, and a disc-shaped rear flange 9 located at an appropriate distance from the flange. and a cylindrical part 10 which connects both flanges 8 and 9 and has a smooth outer circumferential surface, and a hook part 11 is attached to the periphery of the front flange 8 to connect to the front fin of the inner hook 5. 5d, and a synthetic resin attachment piece 12 having a protrusion 12a is inserted and fixed into the cylindrical portion 10.

Therefore, the insertion part body 7 is inserted into the inner hook 5 through the center hole 12b of the mounting piece 12 and the support shaft 5e of the inner hook 5.
This is done by elastic fitting between the protrusion 12a and a positioning hole (not shown) drilled in the inner hook 5.

When the insertion body 7 is inserted into the predetermined position in the inner hook 5 as described above, the relative positional relationship between the insertion body 7 and the inner hook 5 is as follows. It is formed to be in the state described.

That is, the hook portion 11 formed on the periphery of the front collar portion 8
is located at almost the same angular position as the throat 5b of the inner pot 5 (see FIGS. 1 and 6), and is located behind the front fin 5d of the inner hook 5 facing itself (see FIG. 4). It is located on the right side).

Following the hook portion 11, the throat portion 5b of the inner pot 5
The peripheral edge part 8a of the collar part 8, which exists in an angular range of at least 90 degrees from A peripheral edge part 8 located within an angular range extending from the peripheral edge part 8a to the heel part 5c of the inner hook 5.
b is located forward (to the right in FIG. 5) of the front fin portion 5d of the inner hook 5 that faces it.

1 and 2, reference numeral 13 indicates a bobbin thread supply source for forming a double chainstitch, which is fixed under the bed 1 via appropriate attachment means; 14.15 indicates a thread guide; and 16 18 and 19 are thread guides provided on the hook 4 and the driver 7; 7 into the inner hook 5 to perform double chainstitch, the bobbin thread T2 for forming the double chainstitch is passed from the supply source 13 through the thread guide 14.15 under tension. The yarn reaches the device 16, is introduced from the yarn take-up spring 17 into the cauldron 4 via the yarn guides 18 and 19, and is then led out to the right side through the needle hole 2a of the needle plate 2.

A self-stitching mode of the double chainstitch device configured as above will be described with reference to FIG. 6.

FIG. 6a shows the state when the hand 3 is at the lowest point, and the inner hook 5 has finished its backward movement and is about to start moving forward.

Further, the bobbin thread T2 introduced into the large hook 4 from the bobbin thread supply source 13 as described above is bent behind the front collar portion 8 of the insertion portion body 7, that is, around the cylindrical portion 10, and is bent around the inner hook 5. Front fin 5
d, and the needle hole 2a of the throat plate 2 (this needle hole 2a
is elongated in the cloth feeding direction) and is connected to a seam formed on the work cloth (not shown).

When the needle 3 starts to rise from this state, the inner hook 5 also starts to move forward, and at the beginning, as shown in FIG.
The thread ring catching beak 5a captures the thread ring 11 of the upper thread T1 formed behind the eye of the needle 3, and the hook portion 11 of the insertion body 7 captures the lower thread T2.

This capture occurs when the bobbin thread T2 passes through the rear of the front flange 8 and is led out to the front of the front fin 5d of the inner hook 5. This is done reliably by the hook part 11 (see FIG. 4).

The thread loop 11 of the upper thread is then enlarged as shown in FIGS. 6c and 6d.

However, in the process of expanding the thread 11, the insertion portion body 7
Since the peripheral edge part 8a of the front collar part 8 that continues to the hook part 11 is located rearward than the front fin part 5d of the inner hook 5 facing it, the front light wave of the thread ring 11 is transmitted to the rear of the collar part 8. When the needle 3 reaches almost the uppermost point and the inner hook 5 reaches the end of forward movement, the thread ring crosses the front thread sliding surface of the collar part 8 without entering the thread ring. 11 is a bobbin thread T2 that passes through the inner hook 5 by the thread pulling action of a thread take-up thread (not shown) and is held by the hook portion 11.
(Fig. 6e shows the end of the thread ring 11).
The thread ring 11 then passes through the gap between the heel 5c of the inner hook 5 and the driver 6.

) Then, the needle 3 starts to move downward, and the inner hook 5 changes to a backward movement, and a feed motion of one pitch is applied to the workpiece cloth, and as shown in FIG. Transfer of the work fabric is completed before penetrating the fabric.

At this time, the thread ring 12 of the bobbin thread T2 is held without coming off from the hook portion 11 (this is caused by the driver 6
The driver 6 is guided by the thread guide 19 provided in the bobbin thread T.
(by acting as a balance on 2).

The rear needle 3 then passes through the work cloth and the needle hole 2a and falls into the thread ring 12 held by the hook portion 11, as shown in FIG. 6g, but as shown in FIG. In the process of moving from to g, the lower thread T2 from the thread guide 19 to the upper thread thread ring 11 is such that the peripheral edge 8b of the collar 8 of the insertion body 7 is against the corresponding front fin 5d of the inner hook 59. Since it is located forward, it always enters the rear of the flange 8.

Then, in the process of the needle 3 falling into the thread ring 12 and further descending, the thread ring 12 separates from the hook portion 11 and becomes in the same state as in the above-mentioned Fig. 6g (see Fig. 6). .

In this state, the bobbin thread T2 passes through the thread guides 18 and 19, passes behind the collar portion 9, and is led out to the front of the front fin portion 5d of the inner hook 5.

Therefore, when the inner hook 5 next moves forward, it is reliably captured by the hook portion 11 at the initial stage, and a new bobbin thread ring is formed.

In the device of this embodiment, a series of double chain stitches are formed by repeating such operations, but when forming a regular lock stitch instead of this double chain stitch, ,
Contrary to the above, the insertion part body 7 is removed from the inner hook 5, a conventional bobbin case is inserted into the inner hook 5 together with the bobbin, and the bobbin thread T2 is removed.

It is well known that a lock stitch is formed by the intertwining of the lower thread and upper thread led out from the bobbin.

When carrying out the double chainstitch mentioned above, a small hole 20 is formed in the front flange 8 of the insertion part body 7 so that the bobbin thread T2 can be easily led out to the right side through the large hook 4. is provided, and the bobbin thread T2 is guided to the right side in the following manner.

That is, the lower thread T2 pulled out from the lower thread supply source 13 by tilting the sewing machine is transferred to the thread guide body 1 as shown in FIGS. 1 and 2.
4.15 and guided into the tensioning device, and subsequently pulled out from its thread take-up spring 17, the bobbin thread is passed through the thread guide 18.19 and then its thread end is inserted into the small hole 20.

This bobbin thread can be threaded by manually driving the sewing machine after introducing the bobbin thread into the hook. The lower thread T2 is led out to the right side through the process shown in FIG. 7.

That is, Fig. 7g shows the state when the needle 3 is located at the highest point, and the inner hook 5 is in a state where it has finished its forward movement and is turning into a backward movement, and in this state, the thread end of the bobbin thread T2 is It is inserted into the small hole 20 of the insertion part body 7.

When the sewing machine user holds the thread end of the upper thread T1 with one hand and turns the sewing machine, the needle 3 descends and the inner hook 5 moves back together with the insertion body 7, as shown in FIG. ), when the needle 3 reaches the lowest point, the shuttlecock 5 completes its backward movement (see Fig. 7, 9).

Thereafter, as the needle 3 moves upward, the inner hook 5 also moves forward, and the thread ring catching beak 5a of the inner hook 5 captures the thread ring 11 of the upper thread T1 that has formed behind the needle 3 at the initial stage. Enlarge (see Figure 7d, e).

When the needle 3 reaches almost the uppermost point, the enlarged thread ring 11 comes off the inner hook 5, begins to be pulled up by the thread pulling action of the thread take-up, passes through the inner hook 5 and the insertion body 7, and then The end of the thread is entangled with the lower thread T2 held in the small hole 20 of the insertion body 7 (see FIG. 7).

This state is sensed by the sewing machine user when the tension that had been acting on the upper thread T1, whose thread end was held, disappears.

Therefore, immediately after that, when the sewing machine is stopped and the thread end of the upper thread T1 that is being held is pulled, the thread end of the lower thread T2 comes off from the small hole 20, as shown in FIG. 7g and h. , while the lower thread T2 is entangled with the upper thread T1, the lower thread T2 is attached to the heel portion 5 of the inner hook 5.
c and the driver 6, and is led out to the right side from the needle hole 2a of the needle plate 2 (see FIG. 1).

As is clear from the above description, the small hole 20 provided in the front collar 8 of the insertion body 7 serves to temporarily hold the thread end of the bobbin thread T2 when leading it out to the right side. It is clear from the above explanation with reference to FIG. 6 that there is no effect during double chain stitching.

Therefore, instead of the small hole 20, a groove or other appropriate holding means may be provided.

Further, the above embodiment is a case in which the present invention is applied to a type of sewing machine in which the inner hook 5 rotates back and forth, but it is also possible to apply the present invention to a type of sewing machine in which the inner hook rotates in one direction. It should be obvious.

As is clear from the above description, the present invention is a sewing machine capable of performing double chainstitch by the action of an insertion body inserted into an inner hook of a conventional lockstitch sewing machine and cooperating with the inner hook and needle. In this method, a holding means such as a hole or a groove capable of temporarily holding the thread end of the bobbin thread for forming the double chain stitch is provided in advance in the insertion part body, and when performing the double chain stitch, a holding means such as a hole or a groove is provided in advance. When the insertion part body is inserted into the inner hook, the thread end of the bobbin thread pulled out from the bobbin thread supply source is temporarily held by the holding means,
Manually move the sewing machine to entangle the thread ring of the upper thread captured by the inner hook with the lower thread held by the holding means, then stop the sewing machine and pull the thread end of the upper thread to remove the lower thread. It is designed to pass through the cauldron and lead out to the right side.
This solves one of the major problems in applying the double chainstitch device to household sewing machines, and allows ordinary sewing machine users to perform the same operation as pulling out the bobbin thread on conventional lockstitch sewing machines. The bobbin thread for forming the double chain stitch opening can now be led out from the inside of the cauldron to the right side very easily, which is very excellent in that it greatly improves the implementation.

[Brief explanation of the drawing]

The drawings show one embodiment embodying the present invention.
The figure is a front view showing the insert body for double chainstitch inserted into the inner hook, Figure 2 is a bottom view of Figure 1, and Figures 3 a to c are front perspective views of the insertion body. , a side view and a rear perspective view, FIG. 4 is an explanatory diagram showing the relative positional relationship between the insertion part body and the inner hook, FIG. 5 is a sectional view taken along the line V-V in FIG. 6, and FIG. FIGS. 7A to 7A are operation diagrams for explaining the operation mode of the double chainstitch, and FIGS. Further, in the figure, 3 is a needle, 4 is a large hook, 5 is an inner hook, 7 is a double chainstitch insertion body, 13 is a bobbin thread supply source, and 20 is a small hole that acts as a holding means.

Claims (1)

[Claims] 1 An inner hook 5 supported in a large hook 4 and rotating reciprocally or in one direction in synchronization with the vertical movement of the needle 3, and a double chain stitch inserted into the inner hook so as to move together with the inner hook. a double chainstitch insert body which cooperates with the needle and the inner hook to form the double chainstitch; In the sewing machine, the sewing machine is adapted to be led out to the right side through the inside of the cauldron from a supply source disposed at a position, and a holding means such as a hole or a groove capable of temporarily holding the thread end of the bobbin thread in the insertion part body. is provided, and when the insertion part body is inserted into the inner hook, the thread end of the bobbin thread pulled out from the supply source is temporarily held by the holding means,
Manually drive the sewing machine to entwine the lower thread held by the holding means with the thread ring of the upper thread captured by the inner shuttle, then stop the sewing machine and pull the thread end of the upper thread to remove the lower thread. A method for leading out a bobbin thread for double chain stitching, characterized in that the bobbin thread is led out to the right side through a cauldron.