JPH11336722A - Screw with thin head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw with a thin head and a small nominal diameter without any sacrifice of a screwing-in function. SOLUTION: The top surface of a head 2 having an engaging hole 5 is formed into a spherical shape with a large radius, and a tapered reinforcing part 10 whose head side is large and thread side is small is formed between the bearing surface 7 of the head 2 and the thread 3 of a leg part 4. This screw 1 with a thin head includes the bottom of the incomplete thread part 11 of the thread 3 formed out of the reinforcing part 10 positioned more outward than the tapered extension of the reinforcing part 10, thus it is possible to provide the screw used for products which are relatively thin without any sacrifice of its function. The leg part is reinforced, therefore screwing-in effort is transferred to the leg part with accuracy without breaking the head at the time of screwing-in the screw with a small nominal diameter. The head is formed into a slightly spherical shape, therefore the respective heads are not brought into close contact with each other during heat treatment or plating process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the use of a screw head which is screwed into a work without projecting the head of the work from spoiling the aesthetic appearance of the work, and without causing any problem in the screw fastening function as a screw. Possible thin-headed screws.

[0002]

2. Description of the Related Art In recent electrical appliances and information equipment products, those which have been improved in performance and are relatively small in size are often used. Electronic devices such as electronic organizers, personal computers, and mobile phones have become widespread. Such products are required to be as light as possible and as thin as possible. At present, small screws having a nominal diameter of 2 mm or less are used for assembling the products. Therefore, in recent years, a screw having the smallest possible size has been developed. As shown in FIG.
Since the head 102 of No. 01 forms an engagement groove 105 to be engaged with the driver, the shape of the head 102 is still the same as before.

[0003]

However, despite the demand for such a thin product,
The inability to cope with the miniaturization of the product due to the limitation of miniaturization of the screw has a great effect on future assembling work. To solve this problem, a screw whose head is thinner than a conventional screw with only a small nominal diameter has been considered, but a driver bit is attached to the head to make the head thinner by forging. Because of the presence of the mating engagement groove, the engagement groove becomes brittle and the engagement groove reaches the leg of the screw, so that the material of the leg is thinned or broken, and the function of the screw is not obtained. In addition, when heat treatment and plating are performed to give the necessary strength to the screw, if the top surface of the head is flat, the volume of the head is small, so that the heads adhere to each other during the processing operation. In such a case, there is a problem that the heat treatment and the plating process are incomplete.

[0004] An object of the present invention is to provide a screw which solves such a problem and which does not impair the screwing function even in a screw having a small head thickness and a small nominal diameter.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a head 2 having an engaging groove 5 with which a driver bit is engaged, and a leg united with the head 2 and having a thread 3 formed therein. 4 is a spherical shape formed with a large radius on the upper surface of a head 2 having an engagement hole 5 and a thickness of about 1/3 or less of a nominal diameter of the screw 1. A tapered reinforcing section 10 having a large head side and a small thread side is formed between the seating surface 7 of the head 2 and the thread 3 of the leg 4, and is formed continuously from the reinforcing section 10. This is achieved by providing a thin-headed screw in which the root of the imperfect thread 11 of the thread 3 is located outside the extension of the taper of the reinforcement 10.

[0006]

FIG. 1 is a block diagram showing an embodiment of the present invention.
And FIG. In FIG. 1, 1 is a head 2
And a leg 4 integral with the head 2 and having a thread 3. The head 2 of the screw 1 has a cross-shaped engaging groove 5 for engaging with a driver bit (not shown) on the center line of the leg 4. 4 has been reached. The head 2 is formed to be relatively thinner than the head 2 of the ordinary screw 1. The thickness of the head 2 is set to about 1/3 or less of the nominal diameter of the screw 1. Have been. The upper surface of the head 2 has a spherical shape with a relatively large radius, and the outer peripheral edge of the head 2 is thinner than the thickness at the center.

The leg 4 at a position close to the seating surface 7 of the head 2 has a tapered reinforcing portion 10 on the head side larger than the thread outer diameter of the leg 4 and smaller on the thread side than the screw outer diameter. Is formed. The taper of the reinforcing part 10 has a predetermined thickness between the wall surface 6 of the engaging groove 5 and the angle of the taper is substantially equal to or slightly larger than the wall angle of the engaging groove 5. I have. The thread 3 is formed at the lower part of the reinforcing portion 10 so as to extend to the tip of the leg portion 4, and the reinforcing portion 10 is provided with an incomplete thread portion 11 of the thread 3. The incomplete threaded portion 11 is formed such that the root of the thread 3 is located on the extension of the taper of the reinforcing portion 10 or outside thereof, and the thread 3 is in contact with the wall surface 6 of the engagement groove 5. It is set so as to have a predetermined thickness between them.

In the operation of screwing into the work 20 using the thin-headed screw 1, as shown in FIG.
The driver bit is engaged with the engagement groove 5 of the screw 1 with respect to the prepared hole of the work 20 and the screwing force is transmitted to screw the screw.
At this time, the screwing force from the driver bit is
The screw 3 is screwed into the work 20 with a predetermined screwing force. Then, when the seating surface 7 of the head 2 is seated on the work 20, the screwing operation ends.

[0009]

As is apparent from the above-described embodiments, the present invention has a head 2 having an engaging groove 5 with which a driver bit engages, and a head 3 integral with the head 2 and having a thread 3
In the screw 1 consisting of the leg 4 formed with
The head 2 has a spherical surface formed with a large radius, and the upper surface of the head 2 whose thickness is set to about 1/3 or less of the nominal diameter of the screw 1. A tapered reinforcing section 10 having a larger head side and a smaller thread side is formed between the thread 4 of the section 4 and the reinforcing section 1.
Since the root of the incompletely threaded portion 11 of the thread 3 formed continuously from 0 is the thin-headed screw 1 located outside the extension line of the taper of the reinforcing portion 10, it is small in size and thickness. A screw used for a relatively thin product can be obtained without impairing the original function of the screw, and a thin product can be assembled using this screw in the future. In addition, when the engagement groove reaching the leg of the screw is provided, the leg close to the seat surface of the head is reinforced by the reinforcing portion,
The screwing force is accurately transmitted to the legs when screwing a screw having a small nominal diameter, and the head is not broken during the screwing. Furthermore, when heat treatment and plating are performed to give the necessary strength to the screws, the heads are slightly spherical, so that the heads adhere to each other during the heat treatment and plating. There is a unique effect that the surface treatment can be completely performed without unevenness.

[Brief description of the drawings]

FIG. 1 is a front view of a thin-headed screw showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a screwed state of the present invention.

FIG. 3 is a sectional view showing a screwed state of a conventional screw.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 screw 2 head 3 screw thread 4 leg 5 engagement groove 6 wall 7 seating surface 10 reinforcing part 11 imperfect screw part 20 work

Claims (2)

[Claims] 1. A head 2 having an engaging groove 5 with which a driver bit engages, and a screw thread 3 integrated with the head 2
The upper surface of the head 2 having the engaging hole 5 is formed in a spherical shape with a large radius, and the seat surface 7 of the head 2 and the thread of the leg 4 are formed. 3, a tapered reinforcing portion 10 having a larger head side and a smaller thread side is formed, and the root of the imperfect thread portion 11 of the thread 3 formed continuously from the reinforcing portion 10 is the reinforcing portion. A thin-headed screw located outside the extension of the taper of the part (10). 2. The thickness of the head is 1 / th of the nominal diameter of the screw 1.
The thin-headed screw according to claim 1, wherein the dimension is set to about 3 or less.