JPH08117472A - External hook of fully rotary hook - Google Patents

Abstract

PURPOSE: To secure lubricity and durability without feeding oil by forming the rail groove of the external hook by using a synthetic resin that makes the torque of the external hook larger when sewing machine oil is interposed between the track groove of the external hook and the rail of an internal hook than when not. CONSTITUTION: The vertical fully rotary hook 5 of a sewing machine consists of the external hook 1 and internal hook 3. Then the external hook 1 has a rail groove member 10 arranged on the inner peripheral surface of an external hook main body 9 and is rotated fast by a rotary shaft 6. The internal hook 3, on the other hand, is stopped by a rotation stop member 7 from rotating and the rail 4 is engaged with the rail groove 2. In this case, at least the inner peripheral surface of the rail groove 2 is formed of the synthetic resin which makes the torque, required to drive and rotate the external hook 1, larger when industrial sewing machine oil is interposed between the inner peripheral surface and the outer peripheral surface of the rail 4 than when not. A liquid crystal polymer or an aromatic polyimide resin is used as the synthetic resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer hook for a full rotary hook provided on a lockstitch sewing machine or the like.

[0002]

2. Description of the Related Art A track groove is formed on the inner peripheral part of an outer hook provided in a lockstitch sewing machine, and a rail formed on the outer peripheral part of the inner hook is fitted into the track groove. Only the outer hook is rotationally driven at a high speed in a state in which the inner hook stopping member fixed to the machine body prevents the outer hook from rotating downstream in the rotating direction. Traditional outer and inner hooks are made of steel. Especially the outer hook of an industrial sewing machine is 600
It is rotationally driven at a high speed of about 0 to 10000 rpm.
Therefore, a large frictional force is generated by the sliding contact between the rail groove and the rail, and a large torque is required to rotate the outer hook. If the frictional force between the rail groove and the rail is large, the inner surface of the hook-stop recess of the inner hook that is fitted into the hook-stop member that blocks the rotation of the inner hook contacts with a large force.
The upper thread cannot be pulled out smoothly, which causes the tension of the upper thread to change undesirably, which lowers the sewing quality and wears the track grooves and rails, resulting in poor durability. There is a problem of doing.

In order to solve this problem, it is well known that lubricating oil is supplied between the inner peripheral surface of the outer hook rail groove and the outer peripheral surface of the inner hook rail. The cloth etc. may be contaminated by the lubricating oil.

Therefore, conventionally, there is also a structure in which the rail groove portion of the outer hook is coated with a fluororesin such as Teflon (trade name) having a low friction coefficient.

[0005]

In the prior art as described above, when coating with a fluorine resin or the like, this is sprayed and fired, and the film thickness is usually 10 to 20 μm.
Since it is thin, the durability is low, and there is a problem that it peels off immediately, especially without lubrication.

The object of the present invention is to reduce the friction in the sliding portion between the outer hook and the inner hook as much as possible without oiling, so that the outer hook can be smoothly and stably rotated at a high speed. It is to provide the outer hook of the full rotation hook.

[0007]

SUMMARY OF THE INVENTION According to the present invention, at least the inner peripheral surface of the outer hook rail groove is rotated when an industrial sewing machine oil is interposed between the inner groove surface and the outer peripheral surface of the inner hook rail. There are even outside the sewing machine characterized in that the torque required for driving is made of a synthetic resin which becomes larger than the torque when the industrial sewing machine oil is not used. Further, the present invention is characterized in that the synthetic resin is a liquid crystal polymer. Further, the present invention is characterized in that the synthetic resin is an aromatic polyimide resin.

[0008]

According to the present invention, at least the inner peripheral surface of the outer race rail groove is made of synthetic resin such as liquid crystal polymer,
The synthetic resin such as the liquid crystal polymer has a torque required for rotationally driving the outer hook when an industrial sewing machine oil, which is lubricating oil, is interposed between the inner peripheral surface of the rail groove and the outer peripheral surface of the inner hook rail. , The torque is larger than the torque when the industrial sewing machine oil is not interposed, and therefore it is not necessary to supply such industrial sewing machine oil to the track groove and the rail, and therefore the industrial sewing machine oil, etc. It is possible to prevent the upper thread and the lower thread, and the cloth to be sewn from being soiled by the lubricating oil.

Further, according to the present invention, the torque required for rotationally driving the outer hook can be reduced, and therefore, the detent of the inner hook and the inner hook by engaging with the inner hook of the inner hook are prevented. The force that acts on the inner hook preventing member that prevents rotation can be reduced, and therefore the upper thread loop can easily pass between the inner hook stopping recess and the inner hook stopping member, and the upper thread No large tension is applied to the loop, which can improve the quality of the sewn product.

Further, according to the present invention, by using the liquid crystal polymer or the aromatic polyimide resin, the friction between the inner peripheral surface of the rail groove and the outer peripheral surface of the rail made of the liquid crystal polymer or the aromatic polyimide resin is reduced. In addition, the wear resistance is improved, and thus the durability of the outer hook can be improved. Further, the rotation speed of the outer hook can be further improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a track groove 2 of an outer hook 1 according to an embodiment of the present invention.
2 is a cross-sectional view showing the vicinity of the rail 4 of the inner hook 3 and FIG.
FIG. 3 is a perspective view of a vertical full rotation rotary hook 5 having such a configuration. The outer hook 1 is generally configured to include an outer hook main body 9 and a track groove member 10 provided on an inner peripheral surface of the outer hook main body 9.
It is driven to rotate at high speed. The inner hook 3 is prevented from rotating by the detent member 7, and the rail 4 is retained by being fitted into the rail groove 2 as shown in FIG.

FIG. 3 is an exploded perspective view of the vertical full rotation rotary hook 5. The vertical full rotary hook 5 is basically the outer hook 1 described above.
And the inner hook 3, bobbin 15, and bobbin case 16
It is comprised including. The outer hook 1 is driven to rotate about a horizontal axis. The bobbin 15 is mounted in the bobbin case 16, and the bobbin case 16 is fitted in the inner hook 3. A sword tip 8 for catching the upper thread loop is formed on the outer hook 1.

As shown in FIG. 1, the side wall 2 of the rail groove 2 is shown.
The cross section is roughly U over a, 2b and the bottom 2c.
The rail groove member 10 formed in a V shape is formed. The track groove member 10 is made of a liquid crystal polymer which is a synthetic resin material having a small friction coefficient. The outer hook body 9 and the inner hook 3 including the rail 4 are made of steel, but may be made of other materials, for example, a metal material such as stainless steel, a synthetic resin material, or an inorganic material such as ceramics. The track groove member 10 may be attached to the track groove 2 with an adhesive or the like, or the track groove member 10 may be formed on the track groove 2 by another method.

The liquid crystal polymer used for the rail groove member 10 will be described in detail. The liquid crystal polymer having a rod-shaped rigid component in the main chain of the polymer has a large intermolecular force between the rigid linear components and is well oriented and crystallized during molding, so its heat resistance is extremely excellent and Even if the temperature increases due to the friction of the outer hook 1 that is rotationally driven at a high speed, the heat deformation temperature is extremely high and the deformation does not occur. Further, the liquid crystal polymer has a high strength and a high elastic modulus because it is made of rigid molecular chains and is highly oriented in the flow direction at the time of molding, and the molecular chains are arranged in a fully extended state in the orientation direction. Therefore, even if a tensile force is applied, it does not extend any further and exhibits excellent creep characteristics. Further, the coefficient of linear expansion is extremely small, and especially the coefficient of linear expansion in the flow direction is 1 × 10
It is about ^-5 (cm / cm) / ° C. Such a linear expansion coefficient is one digit lower than that of other synthetic resins, and it is possible to obtain dimensional stability equivalent to that of metal. From this, the dimensional change due to the difference in environmental temperature and humidity such as summer and winter is almost zero. Further, since the liquid crystal polymer has high weather resistance, it can be used for a long period of time. In addition, since the liquid crystal polymer has a similar structure in the molten state and a solidified state, the phase change is slight and the volume change upon solidification is small.

A very interesting characteristic of the liquid crystal polymer is a characteristic of damping vibration. Generally, a soft material such as rubber is excellent in the property of damping vibration,
The liquid crystal polymer has a high elastic modulus as well as a large vibration damping characteristic. In order to improve wear resistance, 30% of carbon fiber may be mixed with the liquid crystal polymer in order to reduce the specific wear amount and the dynamic friction coefficient. The liquid crystal polymer is composed of a copolymer of para-hydroxybenzoic acid and 2-hydroxy-6-naphthoic acid. As another material, two or three or more kinds of naphthalene groups may be used as a constituent component of the main chain bond and a copolymer with another constituent component may be used. The naphthalene group has 1.2-position, 1.4-position, 1.5-position, 1.8-position, 2.3-position.
Is a functional group capable of forming a polyester and / or a polyesteramide, which is a compound having a functional group at two or more substitution positions selected from the 2-position, the 2.6-position and the 2.7-position. Good. That is, the functional group is selected from a hydroxy group, a carboxyl group, an amino group, an ester group and the like.

The naphthalene group may be hydroxynaphthoic acid, dihydroxynaphthalene and / or naphthalenedicarboxylic acid.

The constituents other than the naphthalene group are the p-position phenyl group, the 4,4'-biphenyl group and / or the general formula of Chemical formula 1, that is,

[0018]

Embedded image

(Where X is alkylene (having 1 to 1 carbon atoms)
4) alkylidene (having 1 to 4 carbon atoms), -O-, -S-,
A group selected from —SO—, —SO ₂ —, and —CO—, R,
R'is a reactive group such as a hydroxy group or a carboxyl group or an ester thereof. ) And a substituted derivative thereof. Further, the binding unit of the polymer is preferably an ester and / or an ester amide, and the functional group forming them is selected from a hydroxy group, a carboxyl group, an amino group, an ester group and the like,
Further, preferably, terephthalic acid, hydroquinone, p-
Diacetoxyphenylene, p-hydroxybenzoic acid and their esters, 4,4'-dihydroxybiphenyl, 4,4'-dicarboxybiphenyl, 4-hydroxy-4'-carboxybiphenyl and their esters, formula X is methylene, propenyl or -SO ₂ - in which each dihydroxy form, dicarboxylic body, hydroxy carboxy bodies and their esters are selected, more preferably, terephthalic acid, hydroxybenzoic acid, 4,4' -Dihydroxybiphenyl, 4,
4'-Dicarboxybiphenyl and their esters are selected.

A track groove member 1 made of such a liquid crystal polymer
Even if the outer hook 1 having the rail groove 2 in which 0 is formed is used for a high-speed sewing operation for a long period of time, the wear of the surface of the rail groove 2 is extremely small.

FIG. 4 is a partial sectional view of another embodiment of the present invention. This embodiment is similar to the above-mentioned embodiment, and corresponding parts are designated by the same reference numerals. In this embodiment, the track groove member 11 is formed only on the bottom 2c of the track groove 2 of the outer hook 1. Also with such a configuration, the frictional force between the inner hook 3 and the rail 4 is reduced, and the outer hook 1 can rotate at a high speed.

FIG. 5 is a partial cross-sectional view of still another embodiment of the present invention. This embodiment is similar to each of the embodiments shown in FIGS. 1 to 4, and corresponding parts are designated by the same reference numerals. As shown in FIG. 5, the track groove members 12, 1 are provided only on the opposite side walls 2a, 2b of the track groove 2 of the outer hook 1.
3 may be attached. This example is also within the spirit of the invention.

In the present invention, as in each of the above-described embodiments, at least the inner peripheral surface of the outer hook rail groove is made of liquid crystal polymer or aromatic polyimide resin to reduce the friction coefficient between the rail groove and the rail. The object of the present invention that the outer hook can be rotated with a small torque can be achieved. By using this liquid crystal polymer or aromatic polyimide resin, the following three important effects a, b, and c, that is, (a) the outer hook can be rotationally driven with a small torque, and is especially used as a lubricant for industrial use. The torque when the sewing machine oil is interposed between the inner peripheral surface of the rail groove and the outer peripheral surface of the inner hook rail is larger than the torque when the industrial sewing oil is not interposed, in other words, liquid crystal polymer. When it is used, it is possible to reduce the torque by making it unlubricated. (B) Even in the case of unlubricated oil as described above, the torque between the inner peripheral surface of the rail groove and the outer peripheral surface of the inner hook rail is reduced. The amount of increase in clearance, which is a gap, is extremely small,
If the amount of wear is other synthetic resin, such as Teflon (trade name)
It is sufficiently smaller than fluororesins such as, and therefore has much better durability, and (c) the occurrence of thread balls and thread breaks when not lubricated is sufficiently smaller than when lubricated,
Compared to the sewing machine hook that refuels, both the outer hook and the inner hook are made of steel, the quality of sewing products is improved.
That effect is achieved.

The fact that at least the inner peripheral surface of the rail groove is made of a liquid crystal polymer reduces the friction coefficient of the inner hook 3 with the rail 4, and the outer hook 1 can be rotationally driven with a small torque. It is clear from FIG. 6 showing the experimental results of FIG.

Lines L1 and L2 in FIG. 6 show the characteristics when the outer hook member body is made of steel and the hook member of the sewing machine equipped with the track groove member made of Teflon (trade name) fluororesin is used. There is.

[0026]

[Table 1]

The rotation speed of the outer rotary hook is 4000 to 7000 r
It is pm that the fluororesin is used without lubrication under the operating conditions of high speed in the industrial sewing machine.
As is clear from line L1, it is understood that this is not possible. When an industrial sewing machine is used to refuel with a fluororesin as in line L2, the torque for driving the rotary hook is drastically reduced, but when such an industrial sewing machine oil is used, the upper thread and the lower thread, In addition, there is a big problem that the cloth is contaminated by industrial sewing oil.

In a sewing machine using a conventional vertical full-rotation rotary hook in which the outer hook and the inner hook are made of steel, the outer hook may be refilled with industrial sewing machine oil as shown by a line L5 in FIG. The torque required to drive the rotation of the sewing machine is too large and the quality of the sewn product deteriorates.

In the vertical full rotary hook 5 according to the present invention, the outer hook main body 9 is made of steel, and the track member 10 is made of liquid crystal polymer. In the oil-free construction, as shown by the line L3, Even when the sewing machine is rotating at high speed, the torque required for rotationally driving the outer hook 1 is smaller than that of the line L2 of the outer hook using the refilled fluororesin, and the outer hook of the outer hook using steel is used. It was confirmed that it was sufficiently smaller than the conventional vertical full-rotation rotary hook which had the characteristics shown by the line L5.

Track groove member 1 made of such a liquid crystal polymer
When the industrial sewing machine oil is interposed between the inner peripheral surface of the rail groove 2 and the outer peripheral surface of the rail 4 of the inner hook 3 in the above-described vertical full-rotation rotary hook 5 having 0, as shown by a line L4. It was confirmed that the torque required to drive the outer hook 1 to rotate increased. Therefore, in the present invention, when at least the inner peripheral surface of the track groove is intervened with a lubricant such as industrial sewing machine oil such as liquid crystal polymer, the torque required for rotational driving of the outer hook increases, and the industrial sewing machine oil, etc. It is important to be made of a synthetic resin having the characteristic that the torque is smaller when no lubricant is used, and it is understood that the torque can be sufficiently reduced by making it oil-free.

By using at least the inner peripheral surface of the track groove as a liquid crystal polymer, the inner peripheral surface of the track groove member 10 and the inner hook 3 are formed.
It is clear from FIG. 7 showing the experimental results of the inventor of the present invention that the clearance, which is a clearance between the rail 4 and the outer peripheral surface of the rail 4, is kept substantially constant and wear is extremely small.

[0032]

[Table 2]

In FIG. 7, the inner hook 3 is made of steel,
A steel outer hook body 9 is used. Lines L13, L1
In No. 4, the track groove member 10 made of liquid crystal polymer is fixed. In FIG. 7, the rotation speed of the outer hook is 6500 rpm. The lines L11 and L12 whose track groove members are made of fluororesin cannot withstand use as a vertical full-rotation rotary hook without lubrication because the clearance increase amount increases rapidly in a relatively short time. In the lines L13 and L14 showing the characteristics when the track groove member 10 is a liquid crystal polymer, the clearance increase amount is very small and stable even during the sewing operation of the sewing machine for a long time.
It resembles the characteristic when refueling is performed in a conventional steel hook shown in line L15, that is, a hook in which both the outer hook and the inner hook are made of steel. Steel hooks cannot be used in high speed rotation without lubrication, and according to the present invention,
By using the outer hook 1 in which the liquid crystal polymer is formed on at least the inner peripheral surface of the rail groove 2 as in the lines L13 and L14, the clearance increase amount is small and stable for a long time even without oiling. Therefore, it can be seen that the generation of noise is reduced and the sewing performance is maintained well over a long period of time.

Further, by using the outer hook 1 having the track groove 2 of which at least the inner peripheral surface is made of a liquid crystal polymer according to the present invention, as apparent from FIGS. 8 to 10 showing the experimental results of the present inventors, the yarn ball It can be seen that the number of defective thread breakages is reduced and the quality of the sewn product is improved.

[0035]

[Table 3]

It can be seen that the quality of the sewn product is further improved by making it oil-free, especially in the structure using the liquid crystal polymer. 8 to 10, the rotation speed of the outer hook is 6000 rpm.

8 to 10, in the structure of the outer hook 1 in which the inner peripheral surface of the rail groove is a liquid crystal polymer, the outer hook body 9 is made of steel, and the rail member 10 is made of a liquid crystal polymer. The outer hook with the inner circumferential surface of the rail groove made of steel is entirely made of steel. In these experiments, the inner hook 3 is made of steel. Experiments using refueling are performed using industrial sewing machine oil. According to these experimental results, the number of defective thread balls and thread breakages was reduced in the outer hook 1 using the liquid crystal polymer, regardless of changes in the material and count of the upper and lower threads, and especially in the case of no lubrication. It can be seen that the number of occurrences is reduced and it is understood that the quality of the sewn product is improved.

It can be seen that the above-mentioned effects a, b and c are achieved by using at least the inner peripheral surface of the rail groove as a liquid crystal polymer.

Also in each of the embodiments shown in FIGS. 1 to 5, the same experimental results as those shown in FIGS. 8 to 10 were obtained, and it was confirmed that the constitution of the present invention was excellent.

Further, when a wholly aromatic polyimide resin was used in place of the liquid crystal polymer and an experiment similar to the above was conducted, similarly good results were obtained.

As another embodiment of the present invention, all the outer hooks may be manufactured by using a synthetic resin having the above-mentioned characteristics, for example, a liquid crystal polymer or an aromatic polyimide resin. If it is a synthetic resin having the above characteristics,
Not only liquid crystal polymers and aromatic polyimide resins, but also other synthetic resins can be used.

As another embodiment of the present invention, at least the outer peripheral surface of the rail of the inner hook may be made of a synthetic resin having the above-mentioned characteristics, and at this time, an outer hook made entirely of steel may be used. Alternatively, an outer hook similar to that of the above-described embodiment may be used.

[0043]

According to the present invention, at least the inner peripheral surface of the rail groove of the outer rotary hook is made of a synthetic resin such as liquid crystal polymer, and this synthetic resin forms the inner peripheral surface and the outer peripheral surface of the rail of the inner rotary hook. Has a characteristic that the torque required to drive the rotary hook with the industrial sewing machine oil interposed therebetween is larger than the torque when the industrial sewing machine oil is not interposed. Therefore, the excellent effect that the upper thread and the lower thread as well as the cloth can be prevented from being damaged by the lubricating oil such as the industrial sewing machine oil is achieved.

By being able to be oil-free in this way, lubricating oil such as industrial sewing machine oil is not consumed, and there is no need to realize a structure for supplying such lubricating oil. The configuration can be simplified,
Furthermore, maintenance can be facilitated.

Further, according to the present invention, by using the synthetic resin as described above, it is possible to reduce the torque required for rotational driving of the outer hook without oil supply, and therefore, the upper thread has the inner rotation stopper concave portion of the inner hook. It is also possible to reduce the tension when passing between the place and the detent member fixed to the machine body, thereby improving the quality of the sewn product.

The present invention can be carried out not only with respect to the vertical full-turn hook, but also with respect to the horizontal full-turn hook and half-turn hook.

Further, according to the present invention, since at least the inner peripheral surface of the rail groove is made of liquid crystal polymer or aromatic polyimide resin, friction between the inner peripheral surface and the outer peripheral surface of the rail can be reduced. It is possible to improve the wear resistance and the durability of the outer hook. Further, the rotation speed of the outer hook can be further improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of one embodiment of the present invention.

FIG. 2 is a perspective view of a vertical full rotation rotary hook 5 according to an embodiment of the present invention.

FIG. 3 is an exploded perspective view of a vertical full rotation rotary hook 5.

FIG. 4 is a partial cross-sectional view of another embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of still another embodiment of the present invention.

FIG. 6 is a diagram showing an experimental result by the inventor of the present invention regarding torque required for rotational driving of the outer hook between one embodiment of the present invention and a comparative example.

FIG. 7 is a view showing an increase amount of the clearance, which is a gap between the inner peripheral surface of the rail groove and the outer peripheral surface of the inner hook rail, in one embodiment of the present invention and in the comparative example, that is, an increase amount with the sewing time. It is a figure which shows the experimental result of an inventor.

FIG. 8 is a diagram showing the results of experiments by the present inventor showing the sewn product quality of one example of the present invention and a comparative example when Tetoron # 50 is used as the upper thread and the lower thread.

FIG. 9: Polyester spun # 6 as upper and lower threads
It is a figure which shows the test result of this inventor which shows the sewn product quality of one Example of this invention and a comparative example when 0 is used.

FIG. 10 is a diagram showing the results of an experiment conducted by the present inventor showing the quality of sewn products in one example of the present invention and a comparative example when cotton thread # 120 is used as the upper thread and the lower thread.

[Explanation of symbols]

 1 Outer hook 2 Rail groove 3 Inner hook 4 Rail 5 Vertical full rotation hook 6 Rotation shaft 7 Rotation stop member 8 Sword tip 9 Outer hook main body 10-13 Rail groove member 15 Bobbin 16 Bobbin case

Claims (3)

[Claims] 1. The torque required for rotational driving of the outer hook when the industrial sewing machine oil is interposed between at least the inner peripheral surface of the outer hook rail groove and the outer peripheral surface of the inner hook rail is the industrial level. An outer hook for a sewing machine, which is made of a synthetic resin that has a torque larger than that when a sewing machine oil is not used. 2. The outer hook of the sewing machine according to claim 1, wherein the synthetic resin is a liquid crystal polymer. 3. The outer hook of the sewing machine according to claim 1, wherein the synthetic resin is an aromatic polyimide resin.