JPS59190509A - Small-diameter screw and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Concerning diameter screws.

Conventionally, for watches, especially for this type of watch band, the band was assembled by connecting the band pieces 2 with a small diameter screw 1 of 4 mm (JIS coarse diameter), as shown in Figure 1, which is a plan view of a partial cross section. I was going.

However, even if the small diameter screw 1 is fully tightened, it may loosen due to impact, and if it is retightened, the loosening torque will not be stable. or,
Commercially available screw loosening prevention adhesives generally penetrate into the gap after the screw is tightened, but when it becomes necessary to loosen the screw after it has been released on the market, it may not come loose and there is a risk that the entire band will be worthless. However, there were some disadvantages, such as the fact that it took a long time to attach the layers and the cost was high.

Therefore, the present invention aims to provide a small diameter screw that does not have the above-mentioned two drawbacks and a manufacturing method thereof. The gist is a manufacturing method for small diameter screws.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings to provide an explanation of the present invention.

FIG. 2 is a sectional view showing a state in which a small-diameter screw 1 is placed in a mesh basket 5 and immersed in shellac solution 5 in a beaker 4;
4 is a front view of the small-diameter screw 1, and FIG. 5 is a sectional view showing the state of the side cover of the thin film according to the embodiment of the present invention.

Now, using 5US304 as the material, as shown in Figure 4,
After cleaning the small diameter screws 1 with JIS coarse threads ML, 4, put 500 of them at once into a mesh basket 6 made of a mesh so fine that the small diameter screws 1 will not fall off or get pinched, and shellac them with alcohol. Add 5 to 6 to shellac solution 5 diluted 40 times.
After being immersed while shaking for a second, the net basket 6 is taken out and air at room temperature is blown from below and from the sides for 3 minutes to dry it. '1''
A thin film of shellac of approximately 5 to 70 microns is then coated over the entire surface. Particularly in the threaded portion 1a, the tip of the thread is thin and the root is thick.

After cleaning the clock piece, I assembled it using a small-diameter screw and a piece made of 5US304 with a JIS coarse M-14 tapped finish. Then, small diameter screw 1 showed the results as shown in Table 1.

In this example, the tightening torque was 350 (gram force 4 meters), the thickness of the shellac film was 10 microns, the average value of 10 samples was 10 microns, and the position of the effective diameter was 10 microns, which was the bottom of the screw. C in Figure 5
The diameter is 70 microns.

Table 1 Note that even after tightening the small diameter screw 1 again with a force of 350, the initial value remains between 150 and 350, and even if condition A is performed, the value remains between 100 and 350 until loosened by one turn.

The film thickness of the satay and shellac coats can be adjusted by changing the concentration of the shellac bath solution.

In some cases, π exceeded 350 during the trial, but by dripping alcohol into the screw part, the shellac-barbed small-diameter screw can be easily removed, so the entire bundt will not become unusable.

In addition, if a commercially available anti-loosening adhesive is used, the initial value is high, but
If you turn it a little once, it will loosen) - The torque will quickly drop to zero.The average value of the 191J model is 15.
Enter between 0 and 350.

As described above, according to the present invention, since the shellac coat is a thin film and solid, it can be handled in the same way as screws that are not coated with shellac, which is very convenient.Also, it is very convenient to attach it directly to the body, such as the frame of eyeglasses. It is suitable for items that do not reach high temperatures, such as coatings.Coating can be done at low cost, the loosening of screws is greatly reduced, and the torque for loosening screws is stable.

The coating material, shellac, is solid at room temperature, is not susceptible to water or sweat, has an inexpensive solvent, can be easily formed into a thin film through batch processing, and can be dried in a short time.
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[Brief explanation of the drawing]

Figure 1 is an enlarged partially cutaway plan view of the connecting structure of the band and bridge using a conventional small-diameter screw, and Figure 2 does not show the small-diameter screw immersed in shellac bath. 3 is a schematic cross-sectional front view showing a state in which the small diameter screw 7 is dried; FIG. 4 is an enlarged front view of the small diameter screw 1; FIG.
The figure is a cross-sectional normal dzi view of the shellac-coated small diameter screw 1θ). 6... Shellac thin film, 1... Small diameter screw, 5 - Shellac solution. j-,,'1. j Patent applicant Citizen Ji@wo Co., Ltd. (,,':””'
--: one

Claims (5)

[Claims] (1) A small diameter screw whose contact surface with the mating part is coated with a thin film of shellac. (2) The small diameter screw according to claim 1, wherein the shellac film thickness is 05 to 200 microns. (3) The small diameter screw according to claim 1, wherein the screw diameter is 0.3 to 2 mm. (4) A method for manufacturing small diameter screws coated with shellac, characterized by immersing the screws in a shellac solution and then drying the screws. (5) The method for manufacturing a small-diameter screw according to claim 4, characterized in that the shellac film thickness is determined by the concentration of the shellac solution.