JP2778471B2 - Driving screw device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving screw device comprising a driving screw and a bit for driving the driving screw.

[0002]

[Prior art and its problems] The driving screw is Japanese Patent Publication No. 59
As shown in FIG. 1 of JP-A-39607, the shaft portion is formed from a screw portion and a bullet-shaped tip portion, and is used, for example, when fastening wood, gypsum board, etc. to a steel plate base material,
After hitting the screw head with the bit of the impact tool to penetrate the steel plate, it is further rotated and screwed into wood or gypsum board to fasten the above material.
The rotation of the screw is performed by fitting the tip of the bit into a groove (formed in a cross shape or the like) in the screw head, but the tip of the bit matches the groove in the screw head when hit. Is not always driven.

If the tip of the bit is driven in a state where it does not match the groove in the screw head, the groove in the screw head is deformed and broken,
Since the engagement with the bit is not performed well, the driving screw does not follow the rotation of the bit at the time of screwing after hitting, and the bit may run idle, resulting in poor tightening.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a driving screw device in which the above-mentioned drawbacks are eliminated and the tip of a bit is engraved on the screw head at the time of hitting so that the screw can always be reliably screwed. With that purpose.

[0005]

Means for Achieving the Object To achieve the above object, a driving screw device according to the present invention is characterized in that after the driving screw is hit by a bit driven from an impact tool, the bit is rotated to rotate the driving screw. In a driving screw device that is screwed into a material, the cross-sectional shape of the tip of the bit is polygonal, the hardness of the driving screw is smaller than that of the bit, and the upper surface of the screw head is different from the tip shape of the bit. Form a bit receiving groove, make the open end of this bit receiving groove larger than the maximum width of the tip of the bit, and engrave the bit tip shape in the receiving groove of the screw head when the bit hits the driving screw It is characterized by doing.

[0006]

After the driving screw is set below the bit, the bit is hit by hitting the screw head of the driving screw by operating the tool and driving the bit. The tip of the driving screw is driven into the material, but at the same time, the open end of the bit receiving groove is formed larger than the maximum width of the bit tip, so the bit tip hits the inner surface of the bit receiving groove in the screw head I do. Further, since the hardness of the driving screw is smaller than the hardness of the bit, the corner of the tip of the bit bites into the inner surface of the bit receiving groove to engrave the tip of the bit. As a result, another triangular receiving groove corresponding to the tip shape of the bit is formed in the screw receiving groove. Then, when the bit is rotated, the driving screw rotates following the rotation of the bit and is screwed into the material.

As described above, another receiving groove corresponding to the tip shape of the bit is formed in the bit receiving groove of the screw head of the driving screw by the driving operation of the bit. Since the other receiving groove matches the tip shape of the bit and is engaged with the bit, when the bit is rotated, the rotation is accurately transmitted to the driving screw. Therefore, regardless of the direction in which the tip of the bit is driven into the bit receiving groove of the driving screw, the driving screw can always be reliably screwed in without causing the bit to idle.

[0008]

FIG. 1 is a front view of a driving screw device according to the present invention, and FIG. 2 is an enlarged sectional view of a screw head.

In the above figures, reference numeral 1 denotes a bit, and 2 denotes a driving screw.

The bit 1 is driven by a rotary drive mechanism after being struck by a striking mechanism of an impact tool (not shown), and its tip 1a has a triangular cross section as shown in FIG. The driving speed at the time of hitting the bit 1 is usually 10 to 20 m / s.

The driving screw 2 is composed of a screw shaft 2a and a screw head 2b. The screw 3 is formed on the screw shaft 2a, and the tip 5 is formed substantially in a shell shape. .

A bit receiving groove 4 is formed on the upper surface of the screw head 2b. The inner surface of the bit receiving groove 4 is simply formed in a concave shape, and is different from the tip shape of the bit 1.
The dimension w1 of the opening end of the bit receiving groove 4 is formed larger than the maximum width w2 of the tip of the bit 1.

Next, the hardness of the driving screw 2 is set smaller than that of the bit 1. The hardness of the driving screw 2 is a Vickers hardness HRC 20 to 45 (JIS B11).
25), the hardness of the bit 1 is HRC53 or more (JIS B
4633).

According to the above construction, after the driving screw 2 is set below the bit 1, the impact tool is operated to drive the bit 1 so that the bit 1 is
Of the screw head 2b. The tip of the driving screw 2 is driven into the material, but at the same time, the open end of the bit receiving groove 4 is formed to be larger than the maximum width of the tip of the bit 1, so that the tip of the bit 1 has Groove 4
Collides with the inside of Further, since the hardness of the driving screw 2 is smaller than the hardness of the bit 1, as shown in FIG.
The tip corner of the bit bites into the inner surface of the bit receiving groove 4 to engrave the bit 1 tip shape. Thereby, another triangular receiving groove (second receiving groove 4a) corresponding to the tip shape of the bit 1 is formed in the screw receiving groove.

Next, when the bit 1 is rotated while the tip of the bit 1 is biting into the second receiving groove 4a by the driving operation, the driving screw 2 rotates following the rotation of the bit 1, Screwed into the material.

As described above, the driving operation of the bit 1 causes the bit receiving groove 4 of the screw head 2b of the driving screw 2 to be driven.
Is formed with a second receiving groove 4a corresponding to the tip shape of the bit 1. Since the second receiving groove 4a matches the tip shape of the bit 1 as a matter of course, the second receiving groove 4a is engaged with the bit 1, and when the bit 1 is rotated, the rotation is performed by the driving screw. 2 is accurately transmitted. Therefore, even if the tip of the bit 1 is driven into the bit receiving groove 4 of the driving screw 2 in any direction, the bit 1 does not run idle and the driving screw 2 can always be screwed in reliably.

The shape of the tip 1a of the bit 1 is not limited to a triangle. As shown in FIG. 4, the shape may be a quadrangle, another polygon, or a cross.

The receiving groove 4 of the bit 1 is not limited to a concave shape. For example, the shape may be conical as shown in FIG.

[Brief description of the drawings]

FIG. 1 is a front view of a driving screw device according to the present invention.

FIG. 2 is a perspective view of a tip of a bit.

FIG. 3 is an enlarged sectional view of a state in which a bit is driven into a screw head of a driving screw;

FIG. 4 is a bottom view of another example of the tip shape of the bit.

FIG. 5 is an enlarged sectional view of a bit receiving groove of the driving screw;

[Explanation of symbols]

 1 bit 2 driving screw 2b screw head 4 bit receiving groove

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Fukushima 6-6, Hakozakicho, Nihonbashi, Chuo-ku, Tokyo Inside Max Co., Ltd. (56) References JP-B-59-39607 (JP, B2) (58) Survey Field (Int.Cl. ⁶ , DB name) B25C 1/00 F16B 25/00

Claims (1)

(57) [Claims] 1. A driving screw device in which a driving screw is driven by a bit driven from an impact tool and then the bit is rotated to drive the driving screw into a material. At the same time, the hardness of the driving screw is smaller than that of the bit, and a bit receiving groove different from the tip shape of the bit is formed on the upper surface of the screw head. A driving screw device characterized in that the tip of the bit is engraved in a receiving groove of the screw head when the bit hits the driving screw.