JP7473995B2 - Inner-rotating sewing device including crescent hook - Google Patents

Description

The present invention relates to an internal rotation sewing device that includes a crescent hook, and in particular to an internal rotation sewing device that includes a crescent hook that can prevent poor sewing by maintaining the tension of the lower thread supplied to the sewing material and preventing the lower thread from becoming tangled.

A sewing machine is a machine designed to mechanically sew clothes, bags, footwear, and other sewn items quickly and easily.

However, in the end, the tasks of moving the item to be sewn, sewing along the sewing line, and adjusting the sewing machine are the responsibility of the person adjusting the sewing machine, so the efficiency of the sewing work depends on the efficiency of the sewing machine.

The basic principle of a sewing machine is to have a lower thread, pull the upper thread, and mechanically connect the lower thread and the upper thread to form a stitch in the sewn item. Therefore, the lower thread supply device of a sewing machine can be said to be the heart of the sewing machine, and the amount of lower thread a sewing machine has is the most important factor in determining the continuity of sewing work and affects sewing efficiency, so even today, various efforts are being made to increase the amount of lower thread that can be wound on a sewing machine.

Nevertheless, it is understood that the dimensions of the width, length and height of modern sewing machines have gradually developed to be optimized from an ergonomic point of view for people to sew, and the industry is hesitant to make any changes to the basic structure of a sewing machine, which places a certain degree of limitation on the development of the sewing machine's bobbin thread supplying device, which is a part of the sewing machine.

Figure 1 shows a conventional lower thread supplying device for a sewing machine, and Figure 2 shows an exploded view of Figure 1.

As shown in Figures 1 and 2, the conventional lower thread supplying device 1 for a sewing machine is connected to a drive shaft (D) installed on the underside of the sewing machine, and is a device that supplies lower thread while rotating by receiving power from the drive shaft (D).

The shape of the sewing machine's bobbin thread supplying device 1 is cylindrical with a circular planar surface and a relatively large diameter compared to its height, which allows the amount of bobbin thread that can be accommodated in the sewing machine's bobbin thread supplying device 1 to be greatly increased.

The bobbin thread supplying device 1 for such a sewing machine includes a housing portion 10, a gear portion 20, a cover portion 30, a power transmission portion 40, a hook body portion 50, and a case portion 60.

The housing part 10 is cylindrical with one side open and forms an accommodation space inside, and accommodates the rotating gear 23, rotating gear cover 33, power transmission part 40, hook body part 50, etc. in the accommodation space through the open side.

The gear unit 20 is connected on one side to the drive shaft (D) of the sewing machine, receives rotational power from the rotating drive shaft (D), and transmits the rotational force to the power transmission unit 40 by meshing the gear teeth.

The gear unit 20 rotates the power transmission unit 40 by the power transmitted from the drive shaft (D), and the power transmission unit 40 is connected to the hook body unit 50, so that the rotational force of the power transmission unit 40 rotates the hook body unit 50.

The gear section 20 includes a power transmission gear section 21 and a rotating gear 23.

The cover portion 30 is configured to fix the gear portion 20 to the housing portion 10 so that the gear portion 20 is seated on the housing portion 10 and can rotate.

On the cover part 30, multiple fixing holes are formed penetrating from one side to the other side, and the cover part 30 is attached to the housing part 10 by inserting fixing means (F) into the fixing holes.

The cover portion 30 includes a power transmission gear cover portion 31 and a rotating gear cover portion 33.

Figure 3 is a diagram showing the power transmission section of the lower thread supplying device of the sewing machine in Figure 2.

The power transmission unit 40 is configured to rotate in synchronization with the rotating gear 23, with the rotation axis of the rotating gear 23 as the center of rotation.

The power transmission part 40 is formed at an angle on the storage space of the housing part 10 and is configured to propel a part of the hook body part 50 to transmit power.

Figure 4 shows the hook body part of the bobbin thread feeder of the sewing machine in Figure 2.

The hook body part 50 is configured to rotate by receiving rotational power from the power transmission part 40, and is formed in a cylindrical shape with one side open, forming a lower thread storage space inside to store the lower thread, and a recessed part is formed by cutting a certain area from the outside of the hook body part 50 toward the center inside to prevent the needle from interfering with the hook body part when it is lowered after the upper thread is hung on the hook body part 50 and rotates, and when the upper thread becomes entangled with the lower thread, it naturally comes undone from the hook body part 50.

Figure 5 shows a state in which a separation space is formed between the power transmission unit and the hook body unit in the bobbin thread supplying device of the sewing machine shown in Figure 2.

The power transmission part 40 is formed at an angle, and the power transmission part 40 may be separated from the hook body part 50 more as it approaches the upper part.

On the other hand, the power transmission part 40 comes into closer contact with the hook body part 50 as it approaches the lower part, without forming a separating space, so it can be said that the power transmission part 40 propels the lower part of the hook body part 50 to rotate the hook body part 50.

The hook 51 of the hook body portion 50 has a ring-shaped configuration for hooking the upper thread (U), and the end of the hook 51 can be deflected toward the power transmission portion 40.

The rotating plate 41 of the power transmission unit 40 can be tilted at an angle θ, so that the power transmission unit 40 and the hook body part 50 at the upper part of the lower thread supplying device 1 form the widest separation space (E).

Since the separated space (E) is connected to the upper thread inlet/outlet of the housing part 10, the needle pointing downward with the upper thread hooked therethrough passes through the upper thread inlet/outlet of the housing part 10 and enters the separated space (E), at which time the hook 51 hooks the upper thread and rotates.

The case portion 60 is configured to cover the open side of the hook body portion 50 and has an outer peripheral shape that is complementary to the planar shape of the lower thread storage space of the hook body portion 50.

This case part 60 is connected to the hook body part 50 to prevent the lump of bobbin thread seated in the bobbin thread storage space of the hook body part 5 from escaping to the outside.

Here, reference numeral 62 denotes a bobbin thread discharge hole formed in the center of the case portion 60 so that the bobbin thread can be discharged from the bobbin thread storage space of the hook body portion 50.

Figures 6 to 10 are diagrams that show the state in which the lower thread is supplied from the lower thread supplying device of the sewing machine in Figure 1.

As shown in FIGS. 6 to 10, when the hook body part 50 rotates, the lower thread (L) accommodated in the lower thread accommodation space of the hook body part 50 is discharged through the lower thread discharge hole 62 formed in the center of the case part 60. Since the length of the lower thread (L) caught on the upper thread hung on the needle (N) is not constant, there is a problem that the tension of the lower thread (L) is not maintained.

In particular, in the case of FIG. 6, there is a problem in that excessive tension is applied to the lower thread (L), and in the case of FIG. 7, the tension of the lower thread (L) must be constant and taut. If this is not the case, the lower thread (L) may get caught on the hook of the hook body portion 50 and become tangled, resulting in poor sewing.

In the case of Figure 9, when the upper thread (U) is pulled up, the loose part of the lower thread (L) is pulled up together with the upper thread (U), which can cause poor sewing.

KR10-2019-0105315A

The object of the present invention is to provide an internal rotation sewing device including a crescent hook that can prevent poor sewing by maintaining the tension of the lower thread supplied to the sewing material and preventing the lower thread from becoming tangled.

In order to achieve the above object, the internal rotation type sewing device including a crescent hook of the present invention includes a housing part having a hollow cylindrical shape with one side open, a gear part seated on the side opposite to the open side of the housing part and rotated by receiving rotational power from a drive shaft, a power transmission part accommodated inside the housing part and rotated by receiving rotational power from the gear part, and a crescent hook including a hook body part including a ring-shaped hook for hanging an upper thread, the hook body part being accommodated inside the housing part so as to be adjacent to the open side of the housing part more adjacent to the power transmission part and rotating by receiving rotational power from the power transmission part, the hook body part being formed with a lower thread accommodating space in the same direction as the opening direction of the housing part, and the lower thread accommodated in the lower thread accommodating space is discharged between the hook body part and the power transmission part and hooked on the upper thread.

In this case, it is preferable that the hook body portion is cylindrical, has a recessed portion cut from the outside toward the center of the inside, has a hook formed at one end of the recessed portion, and has an end of the hook that is biased toward the power transmission portion.

In addition, a plate-shaped lower thread guide plate is formed at the center of the inner circumferential surface of the recessed portion to guide the lower thread accommodated in the lower thread accommodation space between the hook body portion and the power transmission portion.

The lower thread guide plate is disposed vertically at the center of the inner peripheral surface of the recessed portion, and the lower thread guide plate may be formed with a lower thread discharge hole through which the lower thread can pass.

Furthermore, a convex portion is formed in the middle of the surface of the hook body opposite to the surface on which the bobbin thread storage space is formed, and the edge of the convex portion is formed flat, with multiple pin storage holes formed therethrough.

In addition, a concave recess is formed in the center of the surface of the power transmission part facing the hook body part to correspond to the convex part of the hook body part, and the edge of the recess is formed flat, and multiple power transmission pins are formed to protrude and correspond to the multiple pin accommodating holes so as to transmit rotational power to the hook body part.

The power transmission unit is disposed obliquely inside the housing and propels a portion of the hook body to transmit power.

On the other hand, it is preferable that the gear unit includes a power transmission gear that is connected to the drive shaft and rotates, and a rotating gear that rotates in mesh with the power transmission gear, and that the power transmission unit rotates in synchronization with the rotating gear, with the rotating shaft of the rotating gear as the center of rotation.

The hook of the hook body portion is also characterized by forming a certain separation space between it and the power transmission portion.

At this time, the separated space accommodates the needle that faces up and down with the upper thread threaded through it.

Furthermore, the power transmission unit is disposed obliquely inside the housing unit so as to be spaced apart from the hook body unit as it approaches the upper part of the internal rotation sewing device including the crescent hook, forming a separation space between the power transmission unit at the upper part of the internal rotation sewing device including the crescent hook and the hook body unit.

The housing portion includes a base portion on which the power transmission portion is mounted, and a rim portion that protrudes at a certain height along the outer periphery of the base portion, and the rim portion is cut in a certain area to include an upper thread inlet/outlet that communicates with the space between the power transmission portion and the hook body portion.

Other specific details of the embodiments are included in the "Specific details for implementing the invention" and the attached "Drawings".

The advantages and/or features of the present invention and the method of achieving them will become clearer with reference to the various embodiments described in detail below in conjunction with the accompanying drawings.

However, the present invention is not limited to the configurations of the embodiments disclosed below, and may be embodied in various different forms. However, the embodiments disclosed in this specification are provided to complete the disclosure of the present invention and to fully inform those skilled in the art of the present invention of the scope of the present invention, and the present invention is only defined by the scope of the claims.

In the case of the present invention, a lower thread storage space is formed in the hook body part in the same direction as the opening direction of the housing part, and the lower thread stored in the lower thread storage space is discharged between the hook body part and the power transmission part and hooked onto the upper thread, which has the effect of maintaining the tension of the lower thread supplied to the sewing material and preventing the lower thread from becoming tangled.

This helps prevent poor sewing results that occur when the lower thread tension is not consistent.

1 is a diagram showing a lower thread supplying device for a sewing machine according to the prior art. FIG. 2 is an exploded view of FIG. 1 . 3 is a diagram showing a power transmission section in the lower thread supplying device of the sewing machine of FIG. 2 . 3 is a diagram showing a hook body portion in the lower thread supplying device of the sewing machine of FIG. 2 . 3 is a view showing a state in which a separation space is formed between a power transmission unit and a hook body unit in the lower thread feeder of the sewing machine of FIG. 2; 2 is a diagram illustrating a state in which a lower thread is supplied from a lower thread supplying device of the sewing machine of FIG. 1; 2 is a diagram illustrating a state in which a lower thread is supplied from a lower thread supplying device of the sewing machine of FIG. 1; 2 is a diagram illustrating a state in which a lower thread is supplied from a lower thread supplying device of the sewing machine of FIG. 1; 2 is a diagram illustrating a state in which a lower thread is supplied from a lower thread supplying device of the sewing machine of FIG. 1; 2 is a diagram illustrating a state in which a lower thread is supplied from a lower thread supplying device of the sewing machine of FIG. 1; 1 is a diagram showing an inward rotating sewing device including a crescent hook according to the present invention. FIG. 12 is an exploded view of FIG. 11 . 13 is a diagram showing a hook body portion and a power transmission portion of the inward rotation type sewing device including the crescent hook of FIG. 12. FIG. 14 is a diagram showing the hook body portion and the power transmission portion of FIG. 13 as viewed from the opposite side. 12 is a diagram showing a state in which a lower thread is supplied from the inward rotation sewing device including the crescent hook of FIG. 11 . 12 is a diagram showing a state in which a lower thread is supplied from the inward rotation sewing device including the crescent hook of FIG. 11 . 12 is a diagram showing a state in which a lower thread is supplied from the inward rotation sewing device including the crescent hook of FIG. 11 . 12 is a diagram showing a state in which a lower thread is supplied from the inward rotation sewing device including the crescent hook of FIG. 11 . 12 is a diagram showing a state in which a lower thread is supplied from the inward rotation sewing device including the crescent hook of FIG. 11 .

BEST MODE FOR CARRYING OUT THEINVENTION

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Before describing the present invention in detail, the terms and words used in this specification should never be interpreted in their ordinary or dictionary sense. The inventors of the present invention may appropriately define and use the concepts of various terms in order to explain their invention in the best possible way. Furthermore, these terms and words should be interpreted in a meaning and concept that corresponds to the technical idea of the present invention.

In other words, the terms used in this specification are used only to describe preferred embodiments of the present invention, and are not intended to specifically limit the content of the present invention. These terms are defined in consideration of various possibilities for the present invention.

In addition, in this specification, singular expressions may include plural expressions unless the context clearly indicates otherwise, and similarly, plural expressions may include the singular meaning.

Throughout this specification, when a certain component is described as "comprising" other components, unless specifically stated to the contrary, this does not mean that any other components are excluded, but that any other components may also be included.

Furthermore, when a certain component is described as being "located inside or connected to" another component, this component may be directly connected to the other component, may be in contact with the other component, or may be spaced apart at a certain distance. In the case where the component is spaced apart at a certain distance, a third component or means may be present to fix or connect the component to the other component, and a description of this third component or means may be omitted.

On the other hand, when a component is described as being "directly coupled" or "directly connected" to another component, it must be understood that there is no third component or means present.

Similarly, other expressions describing the relationship between components, such as "between" and "immediately between," or "adjacent to" and "directly adjacent to," should be construed to have the same intent.

In addition, terms such as "one side," "other side," "one side," "other side," "first," and "second," if used in this specification, are used to refer to one component so as to clearly distinguish the one component from other components, and are not used to limit the meaning of the component in question.

In addition, terms relating to location, such as "upper," "lower," "left," and "right," if used herein, should be understood to indicate relative locations in the drawings with respect to the components in question, and should not be understood to refer to absolute locations unless absolute locations are specified for those locations.

Furthermore, in the present specification, the terms "unit", "machine", "module", "apparatus", etc., if used, refer to a unit capable of processing one or more functions or operations, which may be embodied in hardware or software, or a combination of hardware and software.

Furthermore, in this specification, when assigning a drawing number to each component in each drawing, the same component has the same drawing number even if the component is shown in another drawing, i.e., the same reference number in the entire specification indicates the same component.

In the drawings accompanying this specification, the size, position, connection relationship, etc. of each component constituting the present invention may be partially exaggerated, reduced, or omitted in order to sufficiently clearly convey the concept of the present invention or for the convenience of explanation, and therefore the proportions and scales may not be strictly observed.

Furthermore, in the following description of the present invention, detailed explanations of configurations that are deemed to obscure the gist of the present invention, such as publicly known technologies including conventional technologies, may be omitted.

Figure 11 shows an internal rotation sewing device including a crescent hook according to the present invention, and Figure 12 shows an exploded view of Figure 11.

The internal rotation sewing device including the crescent hook according to the present invention is a device that is connected to a drive shaft (D) installed on the lower part of a sewing machine, and provides a bobbin thread while rotating by receiving power from the drive shaft (D), and is composed of a housing part 100, a gear part 200, a power transmission part 300, and a hook body part 400.

The housing part 100 is a hollow cylinder with one side open, and accommodates the power transmission part 300, hook body part 400, etc. through the open side.

Such a housing part 100 can provide a space in which a rotating drive shaft (D) can be housed, but it is preferable that the housing part 100 is configured so that even if the drive shaft (D) rotates, a direct rotational force is not transmitted to the housing part 100, and the housing part 100 is configured to include a base part 110 and a rim part 120.

The base portion 110 is formed in a roughly disk shape, forming a surface on the other side opposite the open side of the housing portion 100, and supports the components housed inside the housing portion 100 (e.g., the power transmission portion 300, the hook body portion 400, etc.).

The base portion 110 has multiple holes formed therein to accommodate the power transmission gear 210 and the rotating gear 220, which will be described later.

The rim portions 120 are formed to protrude at a certain height along the outer periphery of the base portion 110, and an internal space of the housing portion 100 is provided through these rim portions 120, preventing the components housed in the internal space from escaping to the outside.

In addition, the rim portion 120 has a certain area cut out to include an upper thread inlet/outlet 122 that communicates with a space (E) between the power transmission portion 300 and the hook body portion 400, which will be described later.

Regarding the shape of the upper thread inlet/outlet 122, although this is not limited to a specific concept, it may preferably be formed into a rectangular shape.

Through the upper thread entrance/exit 122 thus formed, the needle (N) with the upper thread can enter the internal space of the housing part 100, and the hook (H) of the hook body part 400, which is coupled to the housing part 100 and rotates, can rotate with the upper thread hooked.

The gear part 200 is mounted on the opposite side of the housing part 100 from the open side, and rotates by receiving rotational power from the drive shaft (D).

That is, the gear unit 200 is connected on one side to the drive shaft (D) of the sewing machine, receives rotational power from the rotating drive shaft (D), and transmits the rotational force to the power transmission unit 300 through the meshing of the gear teeth.

The gear section 200 rotates the power transmission section 300 (described later) by the power transmitted from the drive shaft (D), and the power transmission section 300 is connected to the hook body section 400, so that the rotational force of the power transmission section 300 rotates the hook body section 400.

The gear section 200 includes a power transmission gear 210 and a rotating gear 220.

The power transmission gear 210 is directly connected to the drive shaft (D) and configured to rotate together with the rotation of the drive shaft (D), transmitting power to the rotating gear 220.

The rotating gear 220 is configured to rotate in mesh with the power transmission gear 210, and can transmit the rotational force of the power transmission gear 210 due to the rotation of the drive shaft (D).

The configuration of the housing part 100 and the gear part 200 configured as described above is similar or identical to the configuration disclosed in Korean Patent Application No. 10-2018-0025712, which was invented and applied for as a patent by the present invention, and therefore a detailed description will be omitted.

The power transmission unit 300 is housed inside the housing unit 100 and rotates by receiving rotational power from the gear unit 200, and rotates in synchronization with the rotating gear 220 around the rotation axis of the rotating gear 220. A detailed description of the power transmission unit 300 will be given later with reference to Figures 13 and 14.

The hook body portion 400 is housed inside the housing portion 100 so as to be adjacent to the open side of the housing portion 100 rather than the power transmission portion 300, and is configured to include a ring-shaped hook (H) for hooking the upper thread while being rotated by the rotational power transmitted from the power transmission portion 300.

A detailed description of the hook body portion 400 will be provided later with reference to Figures 13 and 14.

Figure 13 is a drawing showing the hook body part and power transmission part of an internal rotation sewing device including the crescent hook of Figure 12, and Figure 14 is a drawing showing the hook body part and power transmission part of Figure 13 as viewed from the opposite side.

The hook body part 400 rotates by receiving rotational power from the power transmission part 300, and is formed in a cylindrical shape with one side open, with a bobbin thread storage space 410 formed in the same direction as the opening of the housing part 100.

In this way, the lower thread accommodated in the lower thread accommodation space 410 is discharged between the hook body portion 400 and the power transmission portion 300 and is configured to be hooked onto the upper thread.

In this manner, the cylindrical hook body part 400 has a recessed part 420 formed by cutting a certain area from the outside toward the center of the inside, and the upper thread is hooked and the needle that descends does not interfere with the hook body part 400, and when the upper thread that is hooked and rotates on the hook body part 400 becomes entangled with the lower thread, it naturally comes off from the hook body part 400.

The recessed portion 420 allows the hook body portion 400 to have a U-shaped planar shape.

A ring-shaped hook (H) is formed at one end of the recessed portion 420, and the end of the hook (H) is preferably biased toward the power transmission unit 300.

In this way, the overall shape of the hook body portion 400 is crescent-shaped, and may be called a "crescent hook."

Meanwhile, a plate-shaped lower thread guide plate (P) is formed at the center of the inner peripheral surface of the recessed portion 420 to guide the lower thread accommodated in the lower thread accommodation space 410 between the hook body portion 400 and the power transmission portion 300.

The lower thread guide plate (P) is arranged vertically in the center of the inner surface of the recessed portion 420, and a lower thread discharge hole (G) is formed in the lower thread guide plate (P) so that the lower thread can pass through.

The unexplained symbol S is a fixed slide for fixing the bobbin case (not shown) to the lower thread storage space 410 of the hook body portion 400.

Furthermore, a convex portion 430 is formed in the center of the side of the hook body portion 400 opposite to the side on which the bobbin thread storage space 410 is formed, and the edge of the convex portion 430 is formed flat, with multiple pin storage holes 440 formed through it.

The pin receiving hole 440 is a hole formed to penetrate from one side to the other side of the hook body part 400 so as to receive the power transmission pin 330 formed in the power transmission part 300.

With regard to the shape of the pin receiving hole 440, this is not limited to a specific concept, but it is preferable that the power transmission pin 330 is formed in a hemispherical shape, and in order to easily receive the power transmission pin, the pin receiving hole 440 is preferably circular.

In addition, the position and number of the pin accommodating holes 440 are preferably such that multiple pin accommodating holes 440 are formed at positions on the hook body portion 400 corresponding to the power transmission pins 330, since the pin accommodating holes 440 are configured to couple with the power transmission pins 330.

Meanwhile, the hook (H) of the hook body part 400 forms a certain space (E) between it and the power transmission part 300, and at this time, the space (E) accommodates the needle that faces up and down with the upper thread hooked.

The power transmission part 300 and the hook body part 400 at the upper part of the internal rotation sewing device including the crescent hook form the widest separation space (E).

This separated space (E) is connected to the upper thread inlet/outlet 122 of the housing part 100, so that the needle pointing downward with the upper thread hooked therethrough passes through the upper thread inlet/outlet 122 of the housing part 100 and enters the separated space (E), at which point the hook (H) hooks the upper thread and rotates.

The power transmission part 300 rotates in synchronization with the rotating gear 220 around the rotation axis of the rotating gear 220, and may be formed obliquely inside the housing part 100 and configured to propel a part of the hook body part 400 to transmit power.

In this way, the power transmission part 300 is formed at an angle, and the power transmission part 300 is more separated from the hook body part 400 as it approaches the upper part, and conversely, as it approaches the lower part, it comes into close contact with the hook body part 400 without forming a separation space (E).

This means that the power transmission unit 300 propels the lower part of the hook body unit 400, causing the hook body unit 400 to rotate.

In addition, the central portion of the surface of the power transmission part 300 facing the hook body part 400 has a recess 310 formed in a concave shape to correspond to the protrusion 430 of the hook body part 400.

The edge of the recess 310 is formed flat, and multiple power transmission pins 330 are formed to protrude so as to correspond to multiple pin receiving holes 440 in order to transmit rotational power to the hook body portion 400.

As mentioned above, the power transmission pin 330 is preferably formed in a hemispherical shape, but can be embodied in any number of other shapes.

Furthermore, the spacing between the multiple power transmission pins 330 may or may not be fixed, and can be said to include all of the various embodiments.

As mentioned above, preferably, the power transmission pins 330 can propel the lower portion of the hook body portion 400 to rotate the hook body portion 400. In order to facilitate the transmission of rotational force, the spacing between adjacent power transmission pins 330 may be narrower in the lower portion of the power transmission portion 300 than in the upper portion of the power transmission portion 300.

Figures 15 to 19 are schematic diagrams showing how the bobbin thread is supplied from the internal rotation sewing device including the crescent hook of Figure 11.

When the lower thread (L) is being fed to the sewing item, maintaining a constant tension in the lower thread (L) is a very important key in determining the quality of the sewing.

The space (E) between the power transmission unit 300 and the hook body unit 400 is connected to the upper thread inlet/outlet 122 of the housing unit 100, so the needle (N) pointing downward with the upper thread (U) hooked enters the space (E) through the upper thread inlet/outlet 122 of the housing unit 100, and at this time the hook (H) begins to rotate with the upper thread (U) hooked.

In addition, the lower thread (L) accommodated in the lower thread accommodation space 410 of the hook body portion 400 is discharged between the hook body portion 400 and the power transmission portion 300 as shown in Figures 15 to 19, and is configured to be hooked onto the upper thread (U), thereby maintaining the tension of the lower thread (L) supplied to the sewing material and preventing the lower thread (L) from becoming tangled, thereby preventing poor sewing that occurs when the tension of the lower thread (L) is not constant.

Although various preferred embodiments of the present invention have been described above using some examples, the description of the various embodiments described in the "Specific Contents for Carrying Out the Invention" section is merely illustrative, and a person with ordinary knowledge in the technical field to which the present invention pertains can understand from the above description that the present invention can be implemented in various modified forms or in an equivalent manner to the present invention.

Furthermore, the present invention can be embodied in various other forms, and therefore the present invention is not limited to the above description. The above description is provided only to complete the disclosure of the present invention and to fully inform those skilled in the art of the present invention of the scope of the present invention, and the present invention is only defined by the claims.

REFERENCE SIGNS LIST 100 Housing portion 110 Base portion 120 Rim portion 122 Upper thread inlet/outlet 200 Gear portion 210 Power transmission gear 220 Rotating gear 300 Power transmission portion 310 Recessed portion 330 Power transmission pin 400 Hook body portion 410 Lower thread accommodating space 420 Depressed portion 430 Protruding portion 440 Pin accommodating hole U Upper thread L Lower thread N Needle E Separation space D Drive shaft H Hook P Lower thread guide plate G Lower thread discharge hole S Bobbin case fixing slide

Claims (12)

An internal rotation sewing device including a housing part having a hollow cylindrical shape with one side open, a gear part seated on the side opposite to the open side of the housing part and rotated by receiving rotational power from a drive shaft, a power transmission part accommodated inside the housing part and rotated by receiving rotational power from the gear part, and a crescent hook accommodated inside the housing part adjacent to the open side of the housing part relative to the power transmission part and rotated by receiving rotational power from the power transmission part, the crescent hook including a hook body part including a ring-shaped hook for hooking an upper thread,
A bobbin thread receiving space is formed in the hook body in the same direction as the opening direction of the housing portion,
The lower thread accommodated in the lower thread accommodating space is discharged between the hook body portion and the power transmission portion and hooked onto the upper thread, thereby maintaining the tension of the lower thread supplied to the sewing material and preventing the lower thread from becoming tangled.
An inward rotating sewing device including a crescent hook. The hook body part is cylindrical, has a recessed part cut from the outside to the center, and has a hook formed at one end of the recessed part, the end of the hook being biased toward the power transmission part.
An inward rotating sewing device comprising the crescent hook according to claim 1. The recessed portion is provided at its inner circumferential surface center with a plate-shaped lower thread guide plate for guiding the lower thread accommodated in the lower thread accommodating space between the hook body portion and the power transmission portion.
An inward rotating sewing device comprising the crescent hook according to claim 2. The lower thread guide plate is disposed vertically at the center of the inner peripheral surface of the recessed portion, and a lower thread discharge hole is formed in the lower thread guide plate so that the lower thread can pass through.
An inward rotating sewing device including the crescent hook according to claim 3. a central portion of a surface of the hook body portion opposite to a surface on which the bobbin thread accommodating space is formed is formed with a convex portion, and an edge of the convex portion is formed flat, and a plurality of pin accommodating holes are formed therethrough.
An inward rotating sewing device comprising the crescent hook according to claim 2. A central portion of a surface of the power transmission portion facing the hook body portion is formed with a concave recess so as to correspond to the convex portion of the hook body portion, and an edge of the concave portion is formed flat, and a plurality of power transmission pins are formed to protrude so as to correspond to the plurality of pin accommodating holes so as to transmit rotational power to the hook body portion.
An inward rotating sewing device including the crescent hook according to claim 5. The power transmission part is disposed obliquely inside the housing part and propels a part of the hook body part to transmit power.
An inward rotating sewing device including the crescent hook according to claim 6. The gear unit includes a power transmission gear that is connected to a drive shaft and rotates, and a rotary gear that meshes with the power transmission gear and rotates,
The power transmission unit rotates in synchronization with the rotating gear around a rotation axis of the rotating gear.
An inward rotating sewing device comprising the crescent hook according to claim 1. The hook is spaced apart from the power transmission part by a certain distance.
An inward rotating sewing device comprising the crescent hook according to claim 2. The separated space accommodates a needle that faces up and down and has an upper thread wound thereon.
An inward rotating sewing device including the crescent hook according to claim 9. The power transmission part is disposed obliquely inside the housing part so as to be spaced apart from the hook body part toward the upper part of the inwardly rotating sewing device including the crescent hook, forming a space between the power transmission part of the upper part of the inwardly rotating sewing device including the crescent hook and the hook body part.
An inward rotating sewing device comprising the crescent hook according to any one of claims 1 to 10. The housing portion includes a base portion on which the power transmission portion is mounted, and a rim portion protruding at a certain height along an outer periphery of the base portion.
The rim portion is cut in a certain area to include an upper thread inlet/outlet communicating with a space between the power transmission portion and the hook body portion.
An inward rotating sewing device including the crescent hook according to claim 11.

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