JPH0229295Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The invention relates to a self-drilling screw, and is particularly applicable to construction board materials such as plasterboard and plywood used as wall and ceiling materials. This invention relates to a self-drilling screw suitable for attaching to materials.

(Prior Art) This type of self-drilling screw used for fastening plasterboard, plywood, etc. is generally called a drywall screw, etc., and is also called a self-drilling screw in JIS, for example, as shown in Figures 8 to 11.
It is configured as shown in the figure.

This self-drilling screw 11 includes a screw shaft portion 14 having a thread 13 protruding from the outer periphery of the shaft portion 12;
A drill portion 15 with a cutting tip or a sharp tip as in this conventional example provided at the tip of the screw shaft portion 14;
A trumpet-shaped head 16 is provided at the rear end of the screw shaft portion 14.

The head 16 has a flat upper end surface 16a, an engagement groove 17 formed in the form of a cross recess or the like that engages with a screwdriver in the center, and a flange 18 formed on the outer peripheral edge. Part 18 is the 10th
As shown in the figure, the terminal end of the tapered surface 16b of the lower neck portion and the upper end surface 16a are formed in such a manner that they extend in parallel and have a flat surface 18a.

Using the self-drilling screw 11 described above, as shown in FIG.
The gypsum board with the lath paper 20 stretched over the surface thereof is attached to a steel base material (not shown) as follows.

First, the drill part 15 drills a hole in the gypsum board, and then the drill part 15 reaches the steel base material and after drilling the steel base material, the screw shaft part 14
and a trumpet-shaped head 16
The upper end surface 16a of the gypsum board is fastened so that it is substantially flush with the surface of the gypsum board. In addition, the upper end surface 1 of the head 16
If 6a has sunk into the plasterboard, use putty or the like to make it flush. The surface of the gypsum board is then subjected to a finishing treatment, such as by applying paint or applying cloth.

(Problems to be Solved by the Invention) However, during the above-mentioned fastening, the lath paper 20 stretched on the surface may be turned over or hung, and the protruding piece 20a may become fluffy from the outer peripheral edge of the head 16 toward the surface. This protruding piece 20 will cause unevenness if the above-mentioned finishing treatment is performed as it is.
It was necessary to manually scrape off the a with sandpaper or the like. Furthermore, when the cross-shaped engagement groove 17 is formed by forging on the head 16, the outer peripheral edge is deformed into a square shape and does not become a perfect circle, and the lath paper 20 is damaged during the tightening process, resulting in the protruding piece 20a. There were problems such as the occurrence of this problem becoming more likely to occur.

Furthermore, since the lower part of the neck did not have cutting ability just before final tightening, an excessive screwing torque was required, and the head bearing surface including the tapered surface 16b did not fit well, and the parts to be fastened were This was also a factor in that a portion of the material was pushed out toward the surface and protruded into fluff-like protrusions as described above.

Incidentally, the above-mentioned protruding pieces are generated by the plywood itself even when the plywood is not covered with lath paper.

Therefore, an object of the present invention is to provide a self-drilling screw that improves the above-mentioned problems.

(Means for Solving the Problems) The present invention provides a latch with a drill portion having a pointed or drilled point at the tip of the screw shaft, and a flange portion formed on the outer peripheral edge at the rear end of the screw shaft. In the self-drilling screw with a shaped head, the flange portion is curved toward the screw shaft portion, and an annular protrusion that presses the surface of the fastened member to prevent the protruding piece from protruding; An annular groove recessed in the head for sealing the protruding piece is formed, and a plurality of counterbore protrusions are provided on the tapered surface formed at the lower neck portion of the head. It is a drilling screw.

(Example) An example of the present invention will be described below based on the drawings. As shown in FIG. 1, the self-drilling screw 1 includes a screw shaft portion 2, a drill portion 3, and a rattle-shaped head 4, similar to the conventional example described above. An engagement groove such as a cross recess is formed in the end surface 4a.

A flange portion 5 is formed on the outer peripheral edge of the head 4, and the flange portion 5 is curved toward the screw shaft portion 2 as shown in FIGS. An annular groove 5b is formed at the end of the tapered surface 4b, and an annular protrusion 5a is formed on the outer peripheral side of the annular groove 5b.

Next, on the tapered surface 4b of the lower part of the head 4a, as shown in FIG. 4b, the height and width gradually increase until reaching the top, and thereafter the height and width gradually decrease, so that the cross section protrudes in a similar half-moon shape. Further, as shown in FIGS. 5 and 6, the counterbore protrusion 9 can have a similar sawtooth cross section to improve cutting performance. Incidentally, reference numeral 6 designates a notch groove provided in the screw thread in order to discharge cutting waste toward the head 4 side and prevent clogging.

When the self-drilling screw 1 having the above configuration is used to fasten a plasterboard, which is a member to be fastened, as shown in FIG. This prevents the protruding piece 8a from protruding, and the protruding piece 8a is sealed within the annular groove 5b.
Further, the flange portion 5 is reinforced with an annular projection 5a,
When forming a locking groove such as a cross recess, the outer periphery of the head 4 is kept perfectly circular, thereby preventing the lath paper 8 forming the protruding piece 8a from curling up, hanging, etc. Further, the plaster 7 in contact with the tapered surface 4b is cut by the counterbore protrusions 9 just before final tightening, and a circular counterbore hole 10 is formed with a space 10a between each counterbore protrusion. is formed. The cutting by the counterbore protrusion 9 reduces the screwing torque of the drill screw 1, and the formed counterbore hole 10 allows the lower part of the neck to fit well. This prevents the protruding piece 8a from protruding toward the surface of the head 4 in cooperation with the annular projection 5a and the annular groove 5b.

(Effects of the invention) As is clear from the above embodiments, according to the self-drilling screw of the invention, the flange portion having the annular protrusion and the annular groove portion does not damage the lath paper and is tightened in a state where it is wound inside. Therefore, the generation of protruding pieces is prevented, and manual scraping with sandpaper or the like is no longer necessary, improving work efficiency. In addition, by cutting the fastened member with the counterbore protrusion, the screwing torque is reduced and the seat fits better, and
Waste such as plaster or lath paper is accommodated in the space formed between each counterbore protrusion, and cooperates with the annular protrusion and annular groove to prevent it from protruding toward the surface side.

[Brief explanation of the drawing]

Fig. 1 is an overall front view of a self-drilling screw according to an embodiment of the present invention, Fig. 2 is an enlarged sectional view of the same main part, Fig. 3 is a cross-sectional view taken from Fig. 1, and Fig. 4 is a cross-sectional view of the same main part.
FIG. 5 is a plan view of the head according to another embodiment, FIG. 6 is a cross-sectional view of FIG. 5, and FIG. Fig. 8 is an overall front view of a conventional self-drilling screw, Fig. 9 is a plan view of the same, and Fig. 10 is a general front view of a conventional self-drilling screw.
The figure is an enlarged sectional view of the same main part, and Figure 11 is XI- of Figure 8.
The XI sectional view and FIG. 12 are partial sectional views showing a fastened state using the same drilling screw. Explanation of symbols, 1, 11... Self-drilling screw, 2, 14... Screw shaft portion, 3, 15... Drill portion, 4, 16... Head, 4a, 16a... Upper end surface, 4b, 16b... ...Tapered surface, 5,18...
Flange portion, 5a... annular projection, 5b... annular groove portion, 6... notch groove, 7... plaster, 8... lath paper,
8a...Protruding piece, 9...Protrusion for counterbore, 10...
Counterbore hole, 10a...space part, 12...shaft part,
13...screw thread, 17...engaging groove, 18a...flat surface.

Claims (1)

[Claims for Utility Model Registration] The tip of the screw shaft is provided with a drill portion with a sharp point or a drilled point, and the rear end of the screw shaft is provided with a lapper-shaped head with a flange formed on the outer peripheral edge. In the self-drilling screw, the flange portion is curved toward the screw shaft portion, and has an annular protrusion that presses the surface of the fastened member to prevent the protruding piece from protruding, and a protruding piece that is recessed on the inner peripheral side of the annular protrusion. A self-drilling screw, characterized in that a plurality of counterbore protrusions are provided on a tapered surface formed at a lower neck portion of the head.