JP2001280324A - Thin head screw - Google Patents

Abstract

(57) [Problem] To provide a screw which cannot be easily loosened without impairing the screwing function even with a screw having a small head thickness and a small nominal diameter. A screw (1) comprising a head (2) and a leg (4) having a thread (3) is formed with a relatively thin head (2) having an engagement groove (10), and a seating surface (5) of the head (2) and a leg are formed. A tapered reinforcing portion 20 having a larger head side and a smaller screw side is formed between the screw 3 and the thread 3 of the screw 4. The screw used for a product having a relatively small thickness can be obtained without impairing its original function. In addition, the neck portion between the engaging groove and the engaging groove is not thinned by the reinforcing portion, so that the screw jumping phenomenon does not occur. Further, since the wall surface of the engagement groove is upright, there is no need to apply a thrust to the driver bit, and no bending occurs even when used for a thin plate-shaped work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to prevent the thrust of a driver bit when tightening a relatively thin plate-shaped work from being received, and to perform a tightening and loosening operation only with a dedicated driver bit. Related to thin headed screws.

[0002]

2. Description of the Related Art In recent electrical appliances and information-related equipment products, those having improved performance and relatively small size are used in many cases. For example, electronic devices such as electronic organizers, personal computers, and mobile phones are widely used. The condition of such a product is that it is as light as possible, and that it is as thin as possible and that the user cannot easily disassemble it. That is the current situation. For this reason, in recent years, a screw having a projection formed at the center thereof has been developed so as to make the screw as small as possible and the engaging groove cannot be easily loosened by the user, as shown in FIG. In addition, the head 102 of the screw 101 has a + -shaped groove 110 which is widely used.
The shape of the head 102 and the engagement groove 110 is still the mainstream. For this reason, at present, the wall surface 111 of the engagement groove 110 which engages with the driver bit is normally inclined by the angle α °.

[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. Due to the engagement groove that fits, the material becomes brittle and the engagement groove reaches the leg of the screw, so that the material of the leg is thinned or torn, so that the function of the screw is not sufficiently obtained. In addition, since the engaging groove has an inclination of an angle α ° on the wall surface due to the relationship with the driver bit, a force acts on the driver bit in a direction in which the driver bit comes out of the engaging groove when the driver bit rotates. , A thrust must be applied to the thin plate-shaped work, and this thrust causes bending. Furthermore, since it is a precision electronic device, it cannot be easily opened and repaired by a user.
There are various problems such as incomplete measures to prevent such problems.

An object of the present invention is to solve such problems and to provide a screw which cannot be easily loosened without impairing the screwing function even with a screw having a small head thickness and a small nominal diameter. is there.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a head 2 having an engaging groove 10 with which a driver bit is engaged, and a leg integrally formed with the head 2 and having a thread 3 formed thereon. The head 2 having the engagement groove 10 is formed relatively thin, and the head side is large between the seating surface 5 of the head 2 and the thread 3 of the leg portion 4 on the screw side. A thin-headed screw that forms a tapered reinforcing portion 20 with a small diameter, and that has a wall surface 11 on which the driver bit engages at least when the engagement groove 10 rotates in the screw tightening direction, is a plane substantially parallel to the axis of the screw 1. Is achieved by providing Further, the object is to form the engaging groove 10 in this configuration into a Y-shape which is radially formed at three equally spaced positions on a circumference centered on the head axis of the screw 1. The engagement groove 10
, The distance from the axis of the screw 1 to the outer peripheral end is
Or smaller than the radius of the root diameter of the thread 3 formed at the bottom. Further, in the reinforcing portion 20 having such a configuration, a thin-headed screw is provided in which the head side is formed to be larger than the thread diameter of the thread 3 and the leg side is formed to be larger than the root diameter of the thread 3 and smaller than the thread diameter. Is achieved by

[0006]

FIG. 1 is a block diagram showing an embodiment of the present invention.
3 through FIG. 1 and 2, 1
Is a screw composed of 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 Y-shaped engaging groove 10 formed on the center line of the leg 4 for engaging with a driver bit (not shown).
In the case of 0, the tip has reached the leg 4. The thickness of the head 2 is relatively thinner than that of a normal screw, and the thickness of the head 2 is set to be about 1/3 or less of the nominal diameter of the screw 1. I have. The upper surface of the head 2 has a substantially flat shape.

[0007] The leg 4 at the position close to the seating surface 5 of the head 2 has a head side larger than the thread diameter of the thread of the leg 4, more specifically, larger than the thread diameter of the thread 3. A tapered reinforcing portion 20 having a diameter on the crest side larger than the root diameter of the screw thread 3 and smaller than the crest diameter is formed. The taper of the reinforcing portion 20 has a predetermined thickness between the wall surface 11 and the bottom surface 12 of the engagement groove 10. The thread 3 is formed at the lower portion of the reinforcing portion 20 so as to extend to the tip of the leg portion 4. The reinforcing portion 20 is provided with an incomplete thread portion 21 of the thread 3. The incomplete thread portion 21 is formed such that the root of the thread 3 is located on the extension of the taper of the reinforcing portion 20 or outside thereof.

Further, a Y-shaped engagement groove 10 is formed in the head 2 so as to have a center on the axis of the screw 1. As shown in FIG. Groove 1 extending in the direction
The 0 wall surface 11 is a surface substantially parallel to the axis, that is, a surface substantially perpendicular to the tightening direction and the loosening direction of the screw 1. For this reason, there is no driving angle between the engagement groove 10 and the driver bit, and even if a screw tightening force is applied, no force to escape upward is generated in the driver bit, and secure tightening is performed without applying thrust. Force will be applied to the screw. On the other hand, the engaging grooves 10 extending radially in three directions connect the adjacent wall surfaces 11 to each other via an arcuate surface 13, and the engaging grooves 10 have a predetermined depth from the head 2 to the reinforcing portion 20. It is dug down along the axis. This ensures engagement with the driver bit.

When screwing into a work (not shown) using such a thin-headed screw 1, a driver bit is inserted into an engagement groove 10 of the screw 1 with respect to a prepared hole (not shown) of the work. Is engaged to transmit the screwing force and screw in.
At this time, the screwing force from the driver bit is
And no force is applied above the driver bit, that is, in the direction in which the driver bit comes off.
Then, the tightening force from the wall surface 11 of the engagement groove 10 is transmitted from the reinforcing portion 20 to the leg portion 4, and the screw thread 3 is screwed into the work with a predetermined screwing force. Thereafter, when the seating surface 5 of the head 2 is seated on the work, the screwing operation ends. In this embodiment, the engagement groove 10 is Y-shaped, but may be a cross groove.

[0010]

According to the present invention, as apparent from the above-described embodiments, the head 2 and the thread 3 having the engagement groove 10 are formed.
In the screw 1 consisting of the leg 4 formed with
0 is formed relatively thin, and a tapered reinforcing portion 20 having a large head side and a small thread side is formed between the seating surface 5 of the head 2 and the thread 3 of the leg 4. And
Since the engaging groove 10 is a thin-headed screw in which the wall surface 11 with which the driver bit engages at least when rotating in the screw tightening direction is a plane substantially parallel to the axis of the screw, it is used for small and relatively thin products. A screw can be obtained without impairing its original function as a screw, and a thin product can be assembled using this screw in the future. Also, even in the process of thinning the head by forging, the neck portion between the engaging groove and the engaging groove is not thinned by the reinforcing portion, so that the screw jumping phenomenon does not occur, and the function as a screw is sufficiently exhibited. be able to. Further, since the wall surface of the engagement groove is upright, no force acts in the direction in which the driver bit comes out of the engagement groove when the driver bit rotates, and therefore,
There is no need to apply thrust to the driver bit, and the work does not bend even when used for a thin plate-shaped work. Further, even when used for assembling precision electronic equipment, since it cannot be loosened unless a dedicated driver bit is used, the risk of unexpected failure due to erroneous repair by the user is reduced, and it can be expected as a preventive measure. Specific effects can be obtained.

[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 an enlarged plan view of FIG.

FIG. 3 is a developed sectional view taken along line AA in FIG. 2;

FIG. 4 is a sectional view of a main part showing a shape of a conventional engagement groove of a screw.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw 2 Head 3 Thread 4 Leg 5 Seat 10 Engagement groove 11 Wall 12 Bottom 13 Arc surface 20 Reinforcement 21 Incomplete thread

Claims (4)

[Claims] A screw comprising a head (2) having an engagement groove with which a driver bit is engaged and a leg (4) integrally formed with the head and having a thread. A head having a groove (10) is formed relatively thin, and a tapered reinforcing portion having a large head side and a small thread side is provided between a seat surface (5) of the head and a thread (3) of a leg. (20)
And a wall (11) on which the driver bit engages at least when the engaging groove rotates in the screw tightening direction, is a flat surface substantially parallel to the axis of the screw. 2. The engagement groove has a Y-shape radially formed at three equally spaced positions on a circumference centered on the head axis of the screw at equal intervals. The screw with a thin head according to claim 1. 3. The engagement groove according to claim 1, wherein the distance from the axis of the screw to the outer peripheral end is smaller than the radius of the root of the thread formed on the leg. Or the screw with a thin head according to 2. 4. The reinforcing part is formed so that the head side has a diameter equal to or larger than the thread diameter of the thread (3) and the leg side has a diameter larger than the root diameter of the screw thread and smaller than the root diameter. Or the screw with a thin head according to 3.