JPH03212289A - Bobbin and bobbin cylinder for sewing machine using bobbin - Google Patents

Abstract

PURPOSE:To prevent a bobbin from racing when sewing operation is stopped by covering the bobbin with fluororesin. CONSTITUTION:Covering layers 15, 16 made of fluororesin or the like are formed on the outer surfaces of flanges 11, 13 of a bobbin, respectively. With the use of the bobbin covered with fluororesin, the fluororesin can make directly contact with an inner bobbin cylinder 4 in which the bobbin is stored, and accordingly, a friction force between the bobbin and the inner bobbin cylinder at a position where the bobbin makes contact with the inner bobbin cylinder, is effected by a degree at which the tension of a bobbin thread does not vary largely, thereby a control force can be applied to the bobbin. With this arrangement, when sewing operation is stopped, the rotation of the bobbin is rapidly and stopped, thereby it is possible to prevent the bobbin from racing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sewing machine hook, and more particularly to a structure for preventing the bobbin stored in the inner hook from idling when the sewing operation is stopped. .

2. Description of the Related Art Conventionally, for example, a vertical full-rotation hook has been placed below the bed of a lockstitch sewing machine. It basically consists of an inner hook that is housed in the hook, a bobbin case that is detachably attached to the inner hook, and a bobbin that is housed inside the bobbin case. One flange of the bobbin stored in the bobbin case is in contact with the bottom of the inner hook, and as the bobbin thread wound around the bobbin is taken out during the sewing operation, the bobbin rotates. It is configured such that the bobbin thread is pulled out while rotating around the axis.

In such prior art, when the sewing operation is stopped,
The bobbin continues to rotate due to inertia, which causes the bobbin thread to become loose within the bobbin case. Therefore, in a sewing machine such as an industrial sewing machine that is configured to rotate an outer hook at high speed, the sewing speed is high, so the bobbin thread is consumed at a high rate, and the bobbin inside the inner hook rotates at a high speed. Up to this point, as the bobbin thread is consumed from radially outward to radially inward,
The rotation speed of the bobbin increases further. Therefore, it is difficult to stop the rotation of the bobbin almost at the same time as the sewing operation is stopped, and if the bobbin thread is unnecessarily fed out in the hobbin case due to such idle rotation due to the inertia of the bobbin, it may cause tangles or balls of thread. It becomes the cause of occurrence.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a bobbin for a sewing machine that can prevent the bobbin from idling when sewing operation is stopped, and a hook using the bobbin.

Means for Solving the Problems The present invention is a bobbin for a sewing machine characterized in that the bobbin is coated with a fluorinated resin.

Further, the present invention provides a bobbin coated with a fluorinated resin,
A sewing machine hook is housed in an inner hook whose inner peripheral surface is coated with a fluorinated resin.

According to the present invention, by using a bobbin coated with a fluorinated resin, the fluorinated resin comes into direct contact with the inner pot in which the bobbin is housed, thereby causing the bobbin and the inner pot to be in direct contact with each other. Braking force can be obtained by increasing the frictional force between the

This can prevent the bobbin from spinning idly when the sewing operation is stopped.

Further, according to the present invention, by using a bobbin coated with fluorinated resin and an inner furnace, the fluorinated resins coated with each other come into contact with each other while the bobbin is housed in the inner furnace. Therefore, a larger frictional force can be obtained, and the bobbin can be prevented from spinning more reliably.

Example FIG. 1 is a sectional view of one embodiment of the present invention.

A generally right cylindrical cylindrical portion 2 having a rail 1 formed on its outer peripheral surface.
and a bottom portion 3 that extends perpendicularly to one end in the axial direction of the cylindrical portion 2.
An inner hook 4 is formed by the bottom portion 3 of the inner hook 4.
A stud 5 is erected toward the open end side. A bobbin case 6 is removably attached to the inner hook 4, and a bobbin 7 according to the present invention is disposed inside the bobbin case 6.
is stored. This bobbin 7 has a right cylindrical winding trunk 9 through which the stud 5 is inserted, and a pair of seven flange 11, 13 fixed to both ends of the winding trunk 9 in the axial direction. A bobbin thread 14 is wound between these flanges 11, 13 from the radially inner side to the radially outer side, and is consumed from the radially outer side to the inner side as the sewing operation is performed. To go. Therefore, the rotation speed of the bobbin 7 increases as the bobbin thread 14 is consumed. A coating layer 15.16 is formed on the surface of each flange 11.13 of such bobbin 7.

This coating layer 15 is made of, for example, a fluorinated resin material,
Preferably, polytetrafluoroethylene (trade name: Teflon) represented by the following general formula is used.

→CF2-CF2→-...(1) However, n is a positive integer.

This tetrafluoroethylene is a white waxy thermoplastic resin with a large molecular weight of 4 million to 10 million and a high melt viscosity.

It can also be used in a high temperature range from -100°C to 260°C, and is resistant to all acids, alkalis, and solvents except molten alkali metals and hot fluorine gas.

By forming the coating layer 15 made of such a fluorinated resin by, for example, baking, the coefficient of dynamic friction against the inner hook 4 is small when the bobbin 7 rotates during sewing, and when the sewing operation is stopped, the inner hook has a low coefficient of kinetic friction. The rotational movement is stopped almost simultaneously due to the sliding friction with 4. As a result, the bobbin thread can be taken out with a preferable tension during sewing, and when the sewing operation is stopped, the bobbin 7
It is possible to prevent the bobbin thread 4 from spinning idly, thereby preventing the bobbin thread 4 from being unwound.

In another embodiment of the present invention, a coating layer similar to the coating layer 15, 16 described above is formed on the surface of the open end side of the bottom 3 of the inner pot 4, and the coating layer 15. .1
The bobbin 7 on which the number 6 is formed may be stored.

With this structure, the coefficient of dynamic friction between the inner hook 4 and the bobbin 7 is reduced during sewing, the bobbin 7 is rotated smoothly and uniformly within the inner hook 4, and the inner hook 4 and the bobbin 7 are rotated smoothly when the sewing operation is stopped. A braking force is applied to the bobbin 7 by the sliding friction force, and the bobbin 7 can be prevented from spinning more reliably.

In other embodiments of the invention, the coating layer 15, 1.6 may be formed only on the bottom 3 of the inner hook 4, or on one flange 11 of the bobbin 7 which is arranged on the bottom side of the inner hook. (or 13) may be formed.

Furthermore, as another embodiment of the present invention, the above-mentioned coating layer 15
．． For No. 16, a tetrafluorohexafluoroethylene copolymer may be used instead of polytetrafluoroethylene.

Effects of the Invention According to the present invention, since the bobbin is coated with a fluorinated resin, it is possible to reduce the so-called dynamic friction coefficient of the inner furnace in which the bobbin is housed. The bobbin can be rotated smoothly, and when the sewing operation is stopped, the rotation of the bobbin can be quickly stopped to prevent idle rotation.

Furthermore, according to the present invention, the inner circumferential surface of the inner hook is coated with a fluorinated resin, and the bobbin coated with the fluorinated resin is housed in the inner hook, so that the coefficient of dynamic friction during rotation of the bobbin can be reduced. This makes it possible to more reliably prevent the bobbin from spinning.

[Brief explanation of drawings]

Fig. 1 is a sectional view of one embodiment of the present invention, and Fig. 2 is an inner pot 4.
FIG. 3...Bottom, 4...Inner pot, 7...Bobbin, 15
．． 16...Covering layer

Claims (2)

[Claims] (1) A bobbin for a sewing machine, characterized in that the bobbin is coated with a fluorinated resin. (2) A sewing machine hook characterized in that a bobbin coated with fluorocarbon resin is housed in an inner hook whose inner peripheral surface is coated with fluorocarbon resin.