JPH1151032A - Resin deposit type locking screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin deposit type locking screw which keeps a sufficient locking effect even if it is repeatedly used, and has resin hardly released out of the ridge and trough of its thread when it is screwed in. SOLUTION: In this resin deposit type locking screw 1, resin powder 13 is applied to the outer circumference of a ridge 11 at the specified position of its leg part 10 by means of spray painting in such a way that its trough is almost filled up with resin powder, and furthermore, the application of resin powder is limited to the surface of the leg part 10 held within an angle of 210 deg. at most in its cross sectional surface normal to the axial line of the leg part 10. By this constitution, no abrupt screwing torque will be applied at the early stage of screwing, and comparatively smooth screwing can thereby be secured. Besides, it is good enough for resin material to be thickened to a certain degree that the trough of the thread is almost fulled up, screwing torque at the time of driving the screw will never be higher than a specified value, for this reason, the case that the screw is in a floating condition or specified locking torque can not be applied, can be reduced in number. Furthermore, since the process required is only to apply resin powder onto the ridge of the thread so as to allow it to be fusion-bonded over to the ridge by heating, the locking screw can thereby be simply manufactured at low costs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a locking screw in which a resin material is welded and fixed around a screw to prevent a male screw screwed into a female screw formed in advance on a work from being loosened as much as possible.

[0002]

2. Description of the Related Art Conventionally, various types of such locking screws have been considered. For example, a resin material is applied to the periphery of a screw leg, and heat is applied thereto to weld the screw to a screw thread or to a screw thread. Some of them have a resin material raised slightly above the thread and welded. In addition to this, assuming that resin material is embedded, cut a groove along the axial direction in the leg of the screw and embed nylon resin in this, or make a hole in the direction perpendicular to the leg There is one in which a resin material is press-fitted to prevent loosening of a screw between the work and a female screw in a screw hole.

[0003]

When the male screw of the screw coated with the resin material on the entire circumference of the leg portion is screwed into the female screw hole of the work, and when the resin material is thinly coated on the valley, Although it can be screwed relatively smoothly and can also have the effect of preventing loosening, on the other hand, in the manufacture of this resin material is applied without considering the thickness of the applied resin material in detail and determining the amount. If the thickness of the screw is too thick, the screwing torque will be higher than the specified value. If it was thin, the necessary loosening torque could not be obtained. When the resin material is raised and welded to a part of the screw thread, when this position reaches the female screw, for example, when the material of the work is iron and the root diameter of the female screw is 4 mm, the thread outer diameter is 3 mm. When five 0.9 mm sample screws are screwed, the maximum screwing torque is 11 to 20 kgf · c
m, and the maximum return torque at this time is 4 to 18K.
gf · cm, and these torques show relatively high values. However, since the resin material rises higher than the thread, the torque varies greatly. Further, when the screwing and unscrewing are repeated five times for one sample screw, the screwing torque is 13 to 3 kgf · cm.
And the return torque is in the range of 10 to 2 kgf · cm,
Both torques have large variations, and the return torque of the repeated return operation is significantly reduced, resulting in poor workability.

Further, a groove is formed in the axial direction of the leg portion, or a hole is formed in a direction perpendicular to the leg portion, and a resin material is fitted into the groove or the hole, which deforms along the female screw when screwed. If you try to get a loosening effect by doing
Since grooves or holes must be cut in the legs in the manufacture of such a device, there are problems such as an increase in the number of manufacturing steps and an increase in cost.

[0005] A first object of the present invention is to provide a locking screw which solves the above-mentioned problems and has a sufficient locking effect even when used repeatedly. It is an object of the present invention to provide a locking screw in which a resin material is relatively difficult to separate from threads and valleys.

[0006]

SUMMARY OF THE INVENTION A first object of the present invention is to:
After applying the powder resin 13 to the surface of the leg 10 of the screw 1,
This is heated and welded to the surface of the thread 11, and this leg 1
0 is screwed into a work to fix the screw 1 in a predetermined position in the axial direction of the leg 10.
The powder resin 13 is spray-applied to the extent that the valley 12 is almost buried in the outer periphery of the leg 1, and the application range of the powder resin 13 is at most 210 in a cross section perpendicular to the axis of the leg 10.
This is achieved by providing a resin welded locking screw that is on the surface of the thread 11 of the leg 10 within ゜.

According to a second object of the present invention, in the first aspect, the valleys 12 are provided near the center of the coating area.
This is achieved by providing a resin welded locking screw which is relatively thickly welded and which is thinly welded away from the center of the application area in the circumferential direction.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, reference numeral 1 denotes a thread 1.
1 is a screw in which a head 10 having a larger diameter is integrally formed with one end of the leg 10 on one end of the leg 10. The head 2 is provided with an engagement hole 3 for engaging a driver bit (not shown) for transmitting a rotational force to the head 2 on the center line of the leg 10. A resin material 13 such as nylon or vinylon is welded at desired positions to the thread 11 and the valley 12 of the leg 10, and the welding of the resin 13 is large in a cross section perpendicular to the axis of the leg 10. Also 210
The application range is within ゜. Further, in this application range, the resin material 13 is relatively thickly welded to the valley 12 near the center of the application range, as shown in FIGS. As shown in FIG. In addition, it is arbitrarily welded in the axial direction in a length range of about 1 to 2 times the diameter of the leg 10. Also in the length direction of the legs 10, the resin material 13 becomes thinner as it goes away from the center, and as shown in FIG.
Outside the application range, the thread 11 is a normal thread.

The resin material 13 is a powder resin, which is sprayed and applied to the thread 11 of the leg 10 in a predetermined amount, and then a high temperature of 200 ° C. is applied for a predetermined time. Thus, the powder resin 13 is welded to the surfaces of the thread 11 and the valley 12 of the leg 10.

[0010] When the screw 1 in which the resin material 13 is welded to the surfaces of the screw threads 11 and the valleys 12 is screwed into a female screw (not shown) in a screw hole of a work (not shown), in the initial stage of screwing, Since the resin material 13 is not welded to the tip of the leg 10 of the screw 1, the thread 11 of the leg 10 is smoothly engaged with the female screw and screwed. Subsequently, when the portion where the resin material 13 is welded reaches the internal thread, since the resin material 13 is thin at first, the screwing torque is screwed without changing much, and the screwing torque gradually increases until it reaches the thickest portion. I do. In this way, the screw 1 is screwed in without increasing the screwing torque rapidly,
The screw 1 surely comes into contact with the work surface and the screwing operation is completed.

At this time, the resin material 13 welded to the thread 11 of the leg 10 of the screw 1 is deformed by the female screw of the work, and is in elastic contact between the female screw and the screw thread 11. When the screw 1 rotates in the loosening direction, the resin material 13
Is closely attached to the surface of the female screw, and resistance is generated.

An experiment of screwing and unscrewing of this loosening set screw was conducted under the same conditions as in the conventional example. That is, a work having a material of iron and a female screw having a root diameter of 4 mm and an external thread diameter of 3 mm was used. When five .9 mm sample screws are screwed in respectively, the maximum screwing torque is 4 to 6 kgf · cm.
And the maximum return torque at this time is 3 to 5 kgf.
・ It is cm. Furthermore, when the screwing and unscrewing operations are repeated five times for one sample screw, the screwing torque is 6 to 4.5 Kgf · cm and the returning torque is in the range of 4.5 to 3 Kgf · cm.
It has been demonstrated that the locking screw 1 of the present invention can obtain a stable torque without variation.

In this embodiment, the head 2 and the leg 1
Although the resin material 13 is welded to the screw 1 made of 0 to prevent loosening, as shown in FIG. 6, for example, a thread 11 is formed on the outer peripheral surface of a cylindrical shaft having a through hole 21. The screw member is screwed and fixed to the work, and the screw member is fixed to the support member 20 of the shaft 22 which is inserted into the through hole 21.
In such a use, the support member 20 does not loosen with respect to the work, and the same operation as in the above-described embodiment can be performed.

[0014]

As is clear from the embodiments described above, the present invention applies the powder resin 13 to the surface of the leg 10 of the screw 1 and then heats it to weld it to the surface of the screw thread 11. In the locking screw for fixing the leg 10 by screwing it into the work, the powder resin 13 is so thick that the valley 12 is almost buried in the outer periphery of the thread 11 at a predetermined position in the axial direction of the leg 10.
And apply the powder resin 13 in the section perpendicular to the axis of the leg 10 by at most 2
Since it is a resin welding type locking screw set on the surface of the thread 11 of the leg 10 within 10 °, the screwing maximum torque is low, it is stable without variation, and there is little change in the return torque. As described above, the screw can be relatively smoothly screwed in without an abrupt screwing torque being applied to the screw at the initial stage of screwing. In addition, since the resin material is welded only in a predetermined application range, it is not necessary to make the thickness of the resin material strict, and it is sufficient that the thread valley is almost filled. The screwing torque does not become higher than the specified value, thereby reducing the possibility of the screw floating state or the failure to obtain the required loosening prevention torque. Further, since the powder resin is only applied to the screw thread and heated and welded, the production can be simplified and can be provided at low cost.

Further, the powder resin 13 is relatively thickly welded to the valley 12 near the center of the coating range, and thinner as the distance from the center of the coating range increases in the circumferential direction. Is less likely to separate from the threads and has elasticity enough to withstand repeated use, so that even when reused, unique effects such as a sufficient locking effect are obtained.

[Brief description of the drawings]

FIG. 1 is a sectional front view of a main part showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along the line B-O in FIG. 2;

FIG. 4 is a sectional view taken along the line C-O in FIG. 2;

FIG. 5 is a sectional view taken along the line D-O in FIG. 2;

FIG. 6 is an enlarged sectional view of a main part showing another embodiment according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 screw 2 head 3 engagement hole 10 leg 11 thread 12 valley 13 resin material 20 support member 21 through hole 22 shaft

Claims (2)

[Claims] A loose set screw for applying a powder resin 13 to the surface of a leg 10 of a screw 1 and then heating and welding the resin to the surface of a screw thread 11 and screwing the leg 10 into a work to fix the screw. In the above, the powder resin 13 is sprayed and applied to such an extent that the valley 12 is almost buried around the outer periphery of the thread 11 at a predetermined position in the axial direction of the leg 10, and the application range of the powder resin 13 is applied to the axis of the leg 10. A resin-welding type locking screw, wherein the screw is provided on the surface of the thread 11 of the leg 10 within at most 210 ° in a vertical cross section. 2. The method according to claim 1, wherein the powder resin is relatively thickly welded to the valley near the center of the coating area, and thinner as the distance from the center of the coating area increases in the circumferential direction. Resin welded locking screws.