JPH0583428U - Self drilling screws - Google Patents

Abstract

(57) [Summary] [Purpose] To facilitate smooth screwing into lightweight steel. In a self-drilling screw 11 in which a drilling portion 13 for drilling is provided at the tip of a screw shaft 12, the outer shape of the drilling portion 13 is angled portions 21, 22 and 23, 24 on the outline of the outer shape viewed from the front. 5 and 25 are provided at a total of 5 or more locations, and the sharpness of the angular portion provides excellent cutting efficiency and allows smooth screwing into lightweight steel.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a self-drilling screw used for attaching building materials and equipment to lightweight steel.

[0002]

[Prior Art]

 As shown in Fig. 6, a self-drilling screw that has been conventionally used to attach building materials and equipment to lightweight steel has a drill part 2 for drilling at the tip of the screw shaft 1, and this drill part 2 is used for the screw shaft. 1 has a conical tip portion 3 and a blade groove 4 is provided on the outer surface on both sides extending from the tip portion 3 to the tip portion of the screw shaft 1.

By the way, the sharpness of the drill portion is important for smooth drilling when the self-drilling screw is screwed into the light-weight steel, and it is preferable that the drill portion has a structure with the highest cutting efficiency.

Therefore, as a result of actually measuring the process of drilling with a drill using a self-drilling screw, it was found that the angular portion of the outer contour of the drill that greatly contributes to the drilling efficiency. It was

[0005]

[Problems to be solved by the device]

 However, in the conventional drill portion, the tip of the sharpened portion 3 and the boundary between the sharpened portion 3 and the screw shaft 1 become the angled portions 5 and 5, and these angled portions 5 and 5 are effective for cutting. However, as described above, there are a total of two angular portions 5 and 5, and there is a problem that a sufficient cutting effect cannot be obtained.

Therefore, an object of the present invention is to provide a self-drilling screw capable of improving the outer shape of a drill portion and significantly improving the drilling efficiency.

[0007]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention is directed to a self-drilling screw having a drilling portion for drilling at the tip of a screw shaft, in which the outer shape of the drilling portion has five or more angular portions on the contour line of the outer shape. It adopts a certain configuration.

[0008]

[Action]

 When the drill pierces the light-weight steel, the angular parts provided on the outer shape of the drill improve the machinability, and since there are five or more parts, each angular part sequentially enters the lightweight steel as the drilling progresses. And then go on and allow a smooth drilling.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 to 5 of the accompanying drawings.

As shown in the figure, the self-drilling screw 11 is formed by providing a drill portion 13 at the front end of the screw shaft 12 and a head portion 14 at the rear end, and the outer shape of the drill portion 13 is on the contour line of the outer shape. It has a shape with five or more angular parts when viewed from the front.

A first example of the drill portion 13 shown in FIG. 1 is a large-diameter drill portion 15 which is continuous with the screw shaft 12 at the tip end side so as to have the same diameter as the screw shaft 12 and the drill portion 15. It is composed of a small-diameter drill portion 17 coaxially connected to the tip via a tapered drill portion 16, and a conical sharpened portion 18 provided at the tip of the small-diameter drilled portion 17. From the sharpened portion 18 to a small-diameter drilled portion 17, Blade grooves 19 are provided on both sides of the outer surface of the tapered drill portion 16 and the large-diameter drill portion 15.

By adopting the multi-stage shape as described above, the outer shape of the drill portion 13 becomes a shape having five angular portions on the contour line of the outer shape when viewed from the front view of FIG.

That is, the angular portion on the contour line of the outer shape has portions 21 and 22 on both sides of the boundary between the large-diameter drill portion 15 and the tapered drill portion 16, and on both sides of the boundary between the small-diameter drill portion 17 and the sharpened portion 18. 23 and 24 and the tip portion 25 of the sharpened portion 18.

A second example of the drill portion 13 shown in FIG. 2 is a large-diameter drill portion 15 connected to the tip side of the screw shaft 12 so as to have the same diameter as the screw shaft 12 and the drill portion 15. It consists of a taper drill portion 16 connected to the tip and a conical sharpened portion 18 provided at the tip of the taper drill portion 16. The blade grooves 19 are provided on both sides, and the outer shape of the drill portion 13 when viewed from the front is shown. The angled portions on the contour line are the portions 21 and 22 on both sides of the boundary between the large-diameter drill portion 15 and the tapered drill portion 16, and the portions 23 and 24 on both sides of the boundary between the taper drill portion 16 and the sharpened portion 18 and the sharpened portion 18. There are a total of five points on the tip portion 25 of the.

A third example of the drill portion 13 shown in FIG. 3 is a modification of the first example described above, and is different from the first example except that the tip end surface of the sharpened portion 18 is a concave arcuate surface with a high center. It is the same as the example of 1.

The fourth example of the drill portion 13 shown in FIG. 4 is also a modification of the first example, except that the tapered drill portion 16 that transitions from the large-diameter drill portion 15 to the small-diameter drill portion 17 has an arc shape. It is the same as the example of 1.

The fifth example of the drill portion 13 shown in FIG. 5 is a modification of the above-described second example, except that each of the taper drill portion 16 and the sharpened portion 18 has a concave arcuate surface. It is the same as the example in 2.

As described above, in the drill portion 13 of each example, there are five angular portions on the outline of the outer shape when viewed from the front, and in order to increase the angular portions, each large diameter drill is used. It is only necessary to form a larger diameter drill part in the middle of the part, and in this case, there are a total of seven square parts.

The self-drilling screw of the present invention is configured as described above and is used for attaching building materials and equipment to the light-weight steel, the drill portion 13 drills the light-weight steel when screwed, and then the screw shaft 12 will be screwed in while screwing.

When the light-weight steel is perforated by the drill portion 13, the drill portion 13 cuts the hole at the blade groove 19, but the angular portion of the outer shape is the portion with excellent sharpness. The drill portion 13 is arranged stepwise so that the angled portions on both sides on the contour line of the outer shape become wider toward the screw shaft 12 side, so that a new angled portion is sequentially cut at each entry accompanying drilling. Therefore, it is possible to drill holes efficiently with a small torque.

[0021]

【effect】

 As described above, according to the present invention, the outer shape of the drill portion of the self-drilling screw has five or more angular portions on the contour line of the external shape, so the angular portion with excellent sharpness improves cutting efficiency. Improved, drilling into light-weight steel is possible with a small pushing force, and it can be screwed in without causing idle rotation or burning of the drill tip.

[Brief description of drawings]

FIG. 1 is a front view showing a first example of a self-drilling screw according to the present invention.

FIG. 2 is a front view showing the second example.

FIG. 3 is a front view showing the third example.

FIG. 4 is a front view showing the fourth example.

FIG. 5 is a front view showing the fifth example.

FIG. 6 is a front view showing a conventional self-drilling screw.

[Explanation of symbols]

 11 Self-drilling screw 12 Screw shaft 13 Drill part 21, 22, 23, 24, 25 Squared part

Claims (1)

[Scope of utility model registration request] 1. A self-drilling screw having a drill portion for drilling at the tip of a screw shaft, wherein the outer shape of the drill portion has five or more angular portions on the contour line of the outer shape. Drilling screw.