JPH0568482U - Inner pot of sewing machine - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an inner hook of a sewing machine, which has improved durability and can reduce friction, and can effectively prevent sewing shrinkage, thread breakage, and thread tightening unevenness. [Configuration] Inner hook body 20a, 21a, 35 and sliding portion 5,
25 and 35a are made of plastic having a small friction coefficient, and wear-prone parts 5a, 5b, 5c, 25a and 25
b and 25c, wear resistant member 8 such as ceramic pin,
28 and 39 are attached to improve the durability of the inner pots 20 and 21.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an inner hook of a sewing machine.

[0002]

[Prior Art]

 Conventionally, the inner pot of the sewing machine is made of steel from the standpoint of durability in industrial sewing machines, except for a part of household sewing machines, and processes such as shaving, quenching, grinding, polishing and hard chrome plating are performed. It was produced after that. When forming the seam of the sewing machine, after the upper thread captured by the outer hook is hidden by the lower thread installed in the inner hook, the thread is pulled up between the inner hook and the inner hook detent member. It is pulled up further and crosses the lower thread in the cloth to complete the seam.

[0003]

[Problems to be solved by the device]

 By the way, as the rotation speed of the sewing machine increases, the friction torque of the sliding parts of the inner hook and the outer hook increases the rotational torque in the same direction as the rotation direction of the outer hook. A force that is pressed against the member is generated. This force hinders the upper thread from passing between the inner hook and the inner hook detent member, and the upper thread must pass while expanding the inner hook pressed against the inner hook detent member. I have to. Therefore, the needle thread needs a tension to withstand this force, which may cause stitch shrinkage, thread breakage, and thread tightening unevenness.

In order to prevent this, the inner pot has been conventionally coated with Teflon or the like having a small friction coefficient as a means for reducing the friction of the sliding portion, but the thickness thereof is limited, and the durability is improved. There was a problem of lack of sex.

Therefore, an object of the present invention is to solve the above problems, improve durability and reduce friction, and effectively prevent sewing shrinkage, thread breakage, and thread tightening unevenness. It is to provide the inner hook of the sewing machine that can.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention comprises an inner hook main body and a sliding portion made of a plastic having a small friction coefficient, and a wear-resistant member is attached to an easily worn portion.

That is, a plastic inner pot main body having a dynamic friction coefficient in the range of 0.07 to 0.2, and a plastic sliding body having a thread dividing portion and a dynamic friction coefficient in the range of 0.07 to 0.2. A moving part and an abrasion resistant member attached to the thread dividing part are provided.

In the above structure, the wear resistant member may be a ceramic pin.

In the above structure, the wear resistant member may be mounted on a predetermined portion of the sliding portion. Further, in the above structure, the metal hook shaft is fixed to the inner hook body, the bobbin is engaged with the hook shaft, the bobbin is covered with the cap, and the cap is fixed by the locking member built in the hook shaft. Alternatively, the bobbin can be retained by being retained by the inner hook main body so as to be able to be released from the lock.

[0010]

[Effect of the device]

 According to the above structure, since the inner hook main body and the sliding portion are made of plastic having a small friction coefficient, even if the rotation speed of the sewing machine is increased, the force with which the inner hook is pressed against the inner hook stopper member is not increased. It is very small, and it is possible to effectively eliminate sewing shrinkage, thread breakage, and thread tightening unevenness. Further, since the wear resistant member is attached to a portion that easily wears, for example, the thread dividing portion of the sliding portion, the durability of the inner hook can be greatly improved. Further, the inner pot of the present invention can greatly improve the productivity, as compared with the conventional inner pot which is machined from steel and has a complicated shape, and then requires multi-step treatment. If the hook shaft is made of metal and the inner hook body is made of plastic with a low friction coefficient, it is possible to effectively prevent the inner hook from reaching a high temperature, and it is possible to replace the bobbin without gloves. It is possible to set the oil-free condition between the inner hook and the outer hook. Therefore, in the conventional case, the inner hook and the outer hook are made of metal, so it is necessary to refuel between both members.If this amount of refueling is too large, oil will adhere to the thread wound on the bobbin. Although the quality of the product may be deteriorated in some cases, the oil-free state can be achieved in this embodiment, and the oil can be prevented from adhering to the yarn.

[0011]

【Example】

 An embodiment according to the present invention will be described below in detail with reference to FIGS.

First, before describing the inner pot 20 according to the present embodiment, the outer pot 1 and the inner pot 2 will be described. FIG. 1 is an assembly view of an outer hook 1, an inner hook 2, and an inner hook rotation preventing member 3.

The outer hook 1 is rotated in the direction of the arrow by a shaft 4 mounted on a machine frame (not shown). On the other hand, the inner hook 2 has a sliding portion 5, a part of which is indicated by a dotted line, protruding from the outer peripheral surface of the inner hook 2 and engaged with the outer hook 1 via the sliding portion 5. The engaging portion 3a of the inner hook detent member 3 fixed to the machine frame is engaged with the recess 6 in the upper portion of the inner hook 2 so that the inner hook 2 rotates following the rotation of the outer hook 1. To prevent it.

There is a gap between the recess 6 in the upper portion of the inner hook 2 and the engaging portion 3a of the inner hook detent member 3 for allowing the upper thread to easily pass therethrough.

FIG. 2 shows a state in which the loop of the upper thread 7 dives around the inner hook 2. The sliding portion 5 of the inner hook 2 is cut off at the upper portion, and the upper thread 7 captured by the outer hook 1 is a cut end portion of the sliding portion 5 of the inner hook 2 (hereinafter referred to as "thread splitting portion"). It is divided into both sides of the inner hook 2 by 5a, and after the outer hook 1 rotates around the inner hook 2 once, it is pulled up by a yarn pulling device (not shown). This is well known.

In the above conventional structure, when the inner hook 2 is entirely made of plastic, the thread splitting portion 5a may be deformed by receiving an impact when the sliding groove 1a of the outer hook 1 is fitted. Further, it may wear due to friction with the upper thread 7.

FIG. 3 shows an example of the inner pot 20 according to an embodiment of the present invention. In order to eliminate the drawbacks of the conventional structure, the main body 20a and the sliding portion 5 of the inner pot 20 are made of plastic having a smaller friction coefficient than steel, that is, a dynamic friction coefficient within a range of 0.07 to 0.2. While integrally molded with plastic, ceramic pins 8, 8 and 8 as wear-resistant members are attached to the important points 5b 1 and 5c of the thread dividing portion 5a and the sliding portion 5, that is, the places that are easily worn. As an example of the above-mentioned plastic, No. of the product name “Polylon” of Amco, a resin manufacturer, is used. 4275 and the product number JRF4 025 of Mitsui Toatsu Chemicals, Inc. are preferable. As the wear resistant member, hardened steel or cemented carbide may be used instead of the ceramic pin 8.

According to the above-described embodiment, since the inner hook main body 20a and the sliding portion 5 are formed by plastic molding having a small friction coefficient, even if the rotation speed of the sewing machine is increased, the inner hook stopper member 3 is not The force with which the hook 20 is pressed is small, and it is possible to effectively eliminate sewing shrinkage, thread breakage, and thread tightening unevenness. Further, since the ceramic pin 8 is attached as a wear-resistant member to a portion that easily wears, for example, the thread splitting portion 5a of the sliding portion 5 and the key portions 5b and 5c, the sliding portion itself may be worn. This is effectively prevented, and the durability of the inner pot 20 can be greatly improved. Further, in the past, when the entire inner hook is made of plastic, the thread dividing portion 5a may be deformed by receiving an impact when the sliding groove 1a of the outer hook 1 is fitted, but according to the present embodiment. For example, since the ceramic pin 8 is attached to the thread dividing portion 5a which is easily deformed, it is possible to effectively prevent the yarn dividing portion 5a from being deformed. Further, the inner pot 20 of the present embodiment can be greatly improved in productivity as compared with the conventional inner pot which is machined from steel having a complicated shape and then requires multi-step treatment. ..

The present invention is not limited to the above embodiment, and can be implemented in various other modes. For example, the shape of the inner pot 20 in FIG. 3, the shape of the ceramic pin 8 as a wear-resistant member, and the key portions 5b and 5c of the sliding portion 5 are merely examples, and other design changes can be made.

For example, it can be applied to the inner pot 21 having the sliding portion 25 as shown in FIG. That is, in FIG. 4, the main body 21a of the upper hook 21 is also made of the same material as that of the upper hook main body 20a, and the ceramic pin 28 is connected to the thread dividing portion 25a of the sliding portion 25 and the important points 25b and 25c. Is attached to. Also in this embodiment, it is possible to obtain the same effects as those of the previous embodiment.

Further, in the above-mentioned embodiment, the inner hook main body 20a, 21a and the sliding portion 5, 25 are integrally formed of plastic, but the inner hook main body and the sliding portion are made of plastic separately. You may make it and assemble it.

Further, as shown in FIGS. 5 to 7, the shuttle shaft 34 is made of metal, and the latch 30, the latch shaft 31, the push pin 32, and the latch spring 33 are built in the through hole 34a. At the same time, the hook shaft 34 is fixed to the inner hook main body 35 by screwing screws 38 or the like. In this way, the inner hook body 35 can be made of plastic. In other words, it is preferable in manufacturing that the hook shaft 34 is made of the same plastic as the inner hook main body 35, but it is difficult to incorporate the above-described latch 30 and the like in the hook shaft 34 because of structural strength. Only the shuttle shaft 34 is made of metal. This makes it possible to reduce the weight of the inner pot as a whole. Also, in the conventional case where the inner pot body is made of metal, friction heat is generated when the inner pot made of metal and the outer pot made of metal slide, and the inner pot becomes hot. However, there was a problem that gloves were needed when changing the bobbin. On the other hand, in this embodiment, since the hook shaft 34 is made of metal and the inner hook main body 35 is made of plastic having a small friction coefficient, it is possible to effectively prevent the inner hook from being in a high temperature state. The bobbin can be replaced without using it, and it is possible to keep the space between the inner hook and the outer hook unlubricated. Therefore, in the conventional one, since the inner hook and the outer hook were made of metal, it was necessary to refuel between both members.If this amount of refueling is too large, oil will stick to the thread wound on the bobbin. As a result, the quality of the product may deteriorate, but in this embodiment, the oil-free state can be achieved, and oil can be prevented from adhering to the yarn. 5 to 7, the bobbin 36 is housed in the cap 37 with the ratch 30 standing upright as shown in FIG. 7, and in this state, the bobbin 36 is inserted into the shuttle shaft 34 so that the inner hook main body 35 After engaging the cap 37 with the cap 37, the latch 30 is tilted in the direction opposite to the direction of the arrow in FIG. 7 to prevent the bobbin 36 from coming off the hook shaft 34 (see FIG. 6). On the other hand, by raising the latch 30 in the direction of the arrow in FIG. 7 and removing the cap 37, the bobbin 36 can be smoothly taken out from the shuttle shaft 34. The inner hook main body 35 also has a sliding portion 35a, and this inner hook main body 35 is also made of the same material as the inner hook main body 20a, and the ceramic pin 39 is attached to the thread dividing portion of the sliding portion 35a. The same effect as that of the previous embodiment is obtained. In this embodiment, the ceramic pin 39 is arranged on the assumption that it is used in the state shown in FIG. 6, that is, in the state where the axial direction of the shuttle shaft 34 is substantially vertical. The ceramic pins 39 may be arranged at desired positions other than the thread dividing section. The hook shaft 34 may be fixed to the inner hook body 35 by insert molding.

[Brief description of drawings]

FIG. 1 is an assembled perspective view of an inner hook, an outer hook, and an inner hook detent member of a sewing machine.

FIG. 2 is a perspective view showing a relationship among an inner hook, an outer hook, an inner hook detent member, and an upper thread according to FIG.

FIG. 3 is a perspective view of an inner hook of a sewing machine according to an embodiment of the present invention.

FIG. 4 is a perspective view of an inner hook of a sewing machine according to another embodiment of the present invention.

FIG. 5 is a plan view of an inner hook of a sewing machine according to still another embodiment of the present invention.

6 is a vertical cross-sectional view of the inner hook of the sewing machine of FIG.

7 is a longitudinal sectional view of the inner hook of the sewing machine of FIG. 5 in a disassembled state.

[Explanation of symbols]

1 ... Outer pot, 1a ... Sliding groove, 2, 20, 21 ... Inner pot, 3 ...
Inner hook stopper member, 4 ... Shaft, 5, 25 ... Sliding part, 5a,
25a ... Thread splitting portion, 5b, 5c, 25b, 25c ... Essential point, 7 ... Upper thread, 8 ... Ceramic pin, 20a, 21a ...
Inner hook body, 30 ... Latch, 31 ... Latch shaft, 32 ... Push pin, 33 ... Latch spring, 34 ... Hook shaft, 35 ... Inner hook body, 35a ... Sliding part, 36 ... Bobbin, 37 ... Cap,
38 ... screw, 39 ... ceramic pin.

Claims (4)

[Scope of utility model registration request] 1. A plastic inner pot body (20a, 21a, 35) having a dynamic friction coefficient within the range of 0.07 to 0.2.
And a yarn splitting portion (5a, 25a) and a dynamic friction coefficient of 0.
Plastic sliding parts within the range of 07-0.2 (5, 2
5, 35a) and an abrasion resistant member (8, 28, 39) attached to the thread dividing section (5a, 25, 35a). 2. The inner hook of the sewing machine according to claim 1, wherein the wear-resistant member (8, 28, 39) is a ceramic pin. 3. The wear resistant member (8, 28, 39)
Is a predetermined portion (5) of the sliding portion (5, 25, 35a).
b, 5c, 25b, 25c) is also attached to the sewing machine according to claim 1 or 2. 4. A metal hook shaft (3) is attached to the inner hook body (35).
4) is fixed, the bobbin (36) is engaged with the shuttle shaft (34), and the bobbin (36) is secured by the cap (37).
And a locking member (3) built in the shuttle shaft (34).
0) through the cap (37) to the bobbin (3
The inner hook of the sewing machine according to any one of claims 1 to 3, wherein 6) is retained by the inner hook main body (35) in a lockable manner.