JP2000310210A - Screw anchor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw anchor, of which the drilling point will not be melted by frictional heat. SOLUTION: This screw anchor is made of plastic, has an outline of flat countersunk head wood screw, has an inlet 13 for an expansion screw formed on an axis from a countersunk head 12, has a recessed part 15 adapted to engage a driver formed on an entrance of the inlet 13, has a slit 16 formed to pass through an axis center between a bottom and a top of the inlet 13, and has a drilling tip 18 which is made of a material that will not be melted by frictional heat mounted at an end face of its point. On the inner surface of the inlet 13, a rib is erected from a uniform position of internal circumference toward the central axis. Material of the drilling tip 18 is selected from among metal, ceramics or heat-resistant plastic having high hardness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a means for fixing a member to a floor, a wall, or the like by an expansion mechanism, wherein the expansion mechanism can be embedded in a floor, a wall, or the like without opening a pilot hole. About.

[0002]

2. Description of the Related Art As shown in FIG. 4, a prior art screw anchor 1 is formed by injection molding hard plastics, and its outer shape is a plate-shaped wood screw having a large screw pitch. The length of the rib is approximately one-third of the length of the shaft, and an introduction hole 3 for the extension screw is provided in the shaft center.
At the entrance of the introduction hole 3, there is provided a recess 5 into which a blade of a Phillips screwdriver is fitted, and a slit 6 is formed from the bottom of the introduction hole 3 so as to pass through the axis with a length of about 1/3. The tapered portion 8 is bent toward one side of the inclined surface 7, extends to a position before the front inclined surface 7, and converges toward the center from both sides of the front inclined surface 7.

[0003]

In the screw anchor according to the prior art, the blade of the electric screwdriver is brought into contact with the recess of the plate, the tip of the screw anchor is pressed to the position to be buried, and the electric screwdriver is started. Then, the tip rubs and the screw part bites in.The screw anchor is buried by the thrust of the screw part, but since the material is thermoplastic, the tip part to be rubbed is melted by frictional heat and the rubbing is done. There is a problem that it becomes insufficient.

[0004] In view of the above problems, it is an object of the present invention to provide a screw anchor in which a tip portion to be rubbed by a cone is not melted by frictional heat.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, the material is made of plastics, the outer shape of which is a dish-shaped wood screw, and an introduction hole for an extension screw is provided in the center axis from the dish. At the entrance of the introduction hole, a recess is provided in which the blade of the driver fits, a slit is formed through the axis between the bottom and the tip of the introduction hole, and the end face of the tip is made of a material that does not melt by frictional heat. Become equipped with a cone drilling tip, and on the inner surface of the introduction hole, a rib is raised from the equally-spaced position of the inner circumference toward the central axis, and the material of the cone drilling tip is
The structure is selected from metals, ceramics, and heat-resistant plastics having high hardness.

According to the present invention constructed as described above, since the drilling tip is attached to the tip of the screw anchor made of plastics material, the drilling portion is reliably embedded because the drilling portion does not melt due to frictional heat. be able to.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. The screw anchor main body 11 is formed by injection molding of a thermoplastic plastic (hard vinyl chloride). Its outer shape is a dish-shaped wood screw having a large screw pitch. An opening 13 for an extension screw is provided at the center of the dish 12. I have.

A stepped rib 14 rises from the quadrant of the inner circumference toward the center in the introduction hole 13 of the expansion screw, and a recess 15 is formed in the end face of the plate 12 in which a blade of a Phillips screwdriver fits. A slit 16 that passes through the axis from the bottom to the tip of the introduction hole 13 is formed, and a flat hole 19 is provided at an end face of the tip, and the end face of the flat hole 19 becomes an inclined surface 17. ing.

In the above-mentioned rectangular hole 19, a drilling tip 1 having a bent portion 20 formed by punching an iron plate is formed.
8 is attached. In addition, the drilling tip 18 is
The flat portion may be formed without forming the bent portion 20.

The material of the drilling tip 18 may be brass, phosphor bronze, ceramics, or heat-resistant plastics having high hardness, in addition to the iron plate. As plastics having high hardness and heat resistance, thermoplastic resins such as fluorocarbon resins, polyethylene terephthalate, polyphenylene sulfide, and polyether ether ketone can be employed in addition to thermosetting resins.

The stepped rib 14 is provided on the inner surface of the introduction hole 13 of the expansion screw to facilitate the screwing of expansion screws having different large and small outer diameters. The expansion screw having a diameter of 3 to 6 mm is screwed. Can be.

The screw anchor 11 is suitable for being embedded in a gypsum board 21 (which can also be used as a sound-absorbing board). When the electric screwdriver is activated by pressing against the position where the board 21 is to be embedded, the gypsum board 21 is rubbed by the rubbing tip 18, and then the screw portion 22 of the screw anchor 11 bites and the embedding is completed.

In this state, the object 23 is set on the gypsum board 21 as shown in FIG.
When screwed into 3, the tip of the extension screw 24 cuts into the slit 16 portion, bisects and expands 25, bites into the inner surface of the gypsum board 21 and the fixed object 23 is fixed to the board 21 surface,
The drilling tip 18 is pushed forward and falls.

[0014]

As described above, according to the present invention, since the drilling tip is not melted by frictional heat, it is reliably drilled and the screw anchor is smoothly embedded.

[Brief description of the drawings]

FIG. 1A is a partially cutaway sectional view of an embodiment of the present invention. FIG. 1B is an exploded perspective view of an embodiment of the present invention.

FIG. 2A is a front view of an embodiment of the present invention. FIG. 2B is a side view of the embodiment of the present invention.

FIG. 3 is an explanatory view of mounting a screw anchor according to the present invention.

4A is a front view of a conventional example. FIG. 4B is a side view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,11 Screw anchor 2,12 Plate 3 hole 4,14 rib 5,15 recess 6,16 slit 7,17 Inclined surface 8 Drilling part 13 Expansion screw introduction hole 18 Drilling tip 19 Flat hole 20 Bending part 21 Board 22 Screw part (of anchor) 23 Fixed object 24 Expansion screw 25 Expansion

Claims (3)

[Claims] The material is made of plastics, the outer shape of which is a dish-shaped wood screw, an introduction hole for an extension screw is provided on the central axis from the dish, and a recess into which the screwdriver blade fits is formed at the entrance of the introduction hole. A screw anchor, wherein a slit is formed through the axis from the bottom to the tip of the introduction hole, and a cone kneading tip made of a material that is not melted by frictional heat is attached to the end face of the tip. 2. The screw anchor according to claim 1, wherein a rib is raised on an inner surface of the introduction hole from an equally-spaced position on an inner periphery toward a central axis. 3. The screw anchor according to claim 1, wherein a material of the drilling tip is selected from metal, ceramics, and heat-resistant plastics having high hardness.