JPH0334427B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a metal fastener used when connecting a non-conductive hard member to a metal base material.

(Prior Art) Floors of prefabricated houses and the like are constructed by connecting boards (non-conductive hard members) to H steel (metallic base material). In order to connect the above board to the H steel, the applicant developed a welding device 20 as shown in FIG.
No. 60-109600). To explain in detail, the welding device 20 includes a capacitor (welding machine main body)
21 and an automatic screwdriver 24, and the automatic screwdriver 24 has a rotating bit 25. Then, the board 3 is attached using a metal fastener 40 in the shape of a wood screw as shown in FIGS. 7 and 8.
0 is connected to the H steel 31. That is, the board 30 is stacked on the H steel 31. One electrode of the capacitor 21 is connected to the H steel 31 via the contact holder 29, and the other electrode is connected to the automatic screwdriver 2.
Connect to the rotation bit 25 of No. 4. Next, the tip 25a of the rotary bit 25 is inserted into the locking hole 41b formed on the top surface 41a of the head 41 of the metal stopper 40.
Insert. From this state, the metal stopper 40 is screwed into the board 30 while being rotated by the automatic screwdriver 24, and when the tip 41 of the metal stopper 40 almost reaches the H steel 31, the capacitor 21 is inserted between them. Electricity is applied to generate a spark between them, melting the tip 42 of the metal stopper 40 and a part of the H steel 31. As the molten metal 36 solidifies, the tip 4 of the metal stopper 40
2 is welded to the H steel 31, and the board 30 is welded to the H steel 31.
Connect to.

(Problems to be Solved by the Invention) However, in the metal stopper 40, since its tip 42 is tapered and pointed, the welding area with the H steel 31 is small, and the amount of molten metal 36 is also small. Because of the small amount, the welding strength between the two was low, and the strength for connecting the board 30 to the H steel 31 was insufficient, leaving room for further improvement.

(Means for Solving the Problems) This invention has been made to solve the above problems, and its gist is to penetrate a non-conductive hard member while rotating and connect the tip to a metal base material. The metal fastener that connects the hard member and the metal base material by electric welding is composed of a head part and a shank part, and the tip surface of the shank part is formed in a flat, non-circular shape. A metal stopper for connecting a hard member is characterized in that a part of the peripheral edge of the surface constitutes a cutting blade, and a protrusion that serves as an electrical path projects from the center of the tip surface.

(Function) A non-conductive hard member is layered on a metal base material. The metal stopper is rotated and cut through the hard member by the cutting blade on its tip surface. Then, when the protrusion on the tip surface of the metal stopper almost reaches the metal base material, electricity is passed between the two to melt the tip end of the metal stopper and a part of the metal base material. Solidification of this molten metal connects the hard member to the metal base material.

(Example) Hereinafter, an example of the present invention will be described based on the drawings of FIGS. 1 to 5.

Reference numeral 1 in FIGS. 1 and 2 is a metal stopper that connects the board 30 (non-conductive hard member) and the H steel 31 (metal base material) as a beam material. . This metal fastener 1 is composed of a head portion 2 and a shank portion 4. Head part 2
has an inverted conical shape, with a cross-shaped locking hole 2b on the top surface 2a and a protrusion 3 with a triangular cross section on the conical surface.
The books are formed respectively. The above shank part 4
The circumference 5 is a threaded portion, and the tip surface 6 is flat. A cutout portion 7 is formed from a portion of the tip surface 6 to a portion of the circumferential surface 5. As a result, the tip surface 6 has a non-circular shape, and a portion of its periphery constitutes a cutting edge 6a. Also,
A protrusion 8 protruding from the center of the tip surface serves as an electrical path.

Reference numeral 20 in FIG. 3 is a welding machine, which electrically welds the metal fastener 1 and the H steel 31. This welding machine 20 has a capacitor (welding machine body) 21
and a pair of cables 2 extending from the capacitor 21
2, 23, and an automatic driver 24. Automatic screwdriver 24 has rotating bit 2
5, a clutch 26, and an interlocking switch 27, which are connected to an air compressor 28. The bit 25 is connected to one electrode of the capacitor 21 via the cable 22 when the interlocking switch 27 is turned on, and at the same time is rotated by compressed air from the air compressor 28. The clutch 26 is linked to the rotary bit 25 and can be disengaged when the torque exceeds a certain level. A contact holder 29 is provided at the tip of the other cable 23.

The process of manufacturing a floor of a prefabricated house using the metal stopper 1 having the above-mentioned structure will be explained with reference to the drawings shown in FIGS. 3 to 5. Note that the board 30 is made of a non-conductive and non-flammable (or flame-retardant) material such as hard wood cement material.

As shown in FIG. 3, a board 30 is placed on the H steel 31. One cable 22 of the capacitor 21 is connected to the rotary bit 25 of the automatic screwdriver 24 as described above, and the other electrode of this capacitor 21 is connected to the cable 23 and the contact holder 2.
It is connected to the H steel 31 via 9. From this state, insert the tip 25a of the rotary bit 25 of the automatic screwdriver 24 into the locking hole 2 of the head 2 of the metal stopper 1.
b, and push the protrusion 8 of the distal end surface 6 of the metal stopper 1 into the surface 30a of the board 30. next,
The interlock switch 27 of the automatic screwdriver 24 is turned on, and the metal stopper 1 is screwed into the H steel 31 from the surface 30a of the board 30 while being rotated by the rotary bit 25. At this time, since the cutting blade 6a of the metal stopper 1 cuts the board 30, the shank portion 4 of the metal stopper 1 cuts the board 30.
penetrate smoothly. Further, the convex portion 3 of the head portion 2 creates a dish-shaped concave portion 3 on the surface 30a of the board 30.
0b, the head portion 2 is accommodated in this recess 30b.

When the interlocking switch 27 is turned on, the electrode of the capacitor 21 and the rotary bit 25 are electrically connected. As shown in FIG. 4, when the protrusion 8 on the tip surface 6 of the metal stopper 1 almost reaches the H steel 31, the capacitor 21 is connected to the cable 22, the rotary bit 25, the metal stopper 1, and the H steel 31. Capacitor 2 via steel 31, contact holder 29, cable 23
1 is formed, the electricity stored in the capacitor 21 instantly flows and sparks occur between the protrusion 8 and the H steel 31. Note that the spark time is approximately 4/1000 seconds. This spark causes the tip of the shank portion 3 of the metal stopper 1 to
A portion of the steel 31 is melted. Although the distal end surface 6 of the metal stopper 1 is flat, since the protrusion 8 is formed at the center thereof, a spark can always be generated at the center of the distal end surface 6. As a result, the heat generated by the spark can be supplied over the entire area of the tip surface 6, and melting can be caused over the entire area of the tip surface 6. After the spark starts, the metal stopper 1 is continued to be screwed in using the automatic screwdriver 24 for a certain period of time. When the molten metal 35 solidifies, a torque above a certain level is applied, the clutch is disengaged, and the rotating bit 25 of the automatic screwdriver 24 no longer turns. After this, the interlocking switch 27 is turned off. the result,
As shown in FIG. 5, the tip of the shank portion 3 of the metal stopper 1 is welded to the H steel 31,
can be easily connected to the H steel 31.

Since the tip surface 6 of the shank portion 4 of the metal stopper 1 is flat, a large welding area can be obtained.
Since a sufficient amount of molten metal 35 can also be secured, the connection between the board 30 and the H steel 31 can be made strong. Furthermore, when the molten metal 35 cools down to room temperature, the molten metal 35 and the metal stopper 1 contract, and the board 30 is crimped by the head portion 2 of the metal stopper 1, thereby making the connection stronger. can do.

This invention is not limited to the above-mentioned embodiments, and various embodiments are possible. For example, FIG. 6 shows another metal fastener 10. As shown in FIG. This metal fastener 10 consists of a head portion 12 and a shank portion 14 having an equilateral triangular cross section. The distal end surface 16 of the shank portion 14 is flat in the shape of an equilateral triangle, and has a protrusion 18 in the center.
stands out. Further, the vicinity of each vertex of the tip surface 16 of the shank portion 14 constitutes a cutting blade 17.

Note that the metal fasteners 1 and 10 of each of the above embodiments can also be applied to the case where a wall is manufactured by connecting a panel (non-conductive hard member) to a crosspiece (metallic base material).

(Effects of the Invention) As explained above, in this invention, by forming the tip surface of the shank portion of the metal fastener flat, the welding area between the metal fastener and the metal base material can be increased. At the same time, sufficient molten metal can be secured, so welding strength can be increased. As a result, the non-conductive hard member can be firmly connected to the metal base material. Further, since the protrusion is provided at the center of the tip surface of the shank portion, the electrical path can be reliably set as a path in the tip surface, and the generated heat can be supplied to the entire area of the tip surface to melt it. Furthermore, in the shank part of the metal stopper, a part of the periphery of the tip surface constitutes a cutting blade, and the metal stopper penetrates the hard member while cutting, so that no cracks will occur in the hard member. .

[Brief explanation of the drawing]

The drawings from FIG. 1 to FIG. 5 show an embodiment of the present invention, and FIG. 1 is a perspective view of the metal stopper, FIG. 2 is a side view of the metal stopper, and FIG. 3 is a side view of the metal stopper. Fig. 4 is a partial cross-sectional view showing the state immediately after the connection work of the hard members has started; Fig. 4 is a cross-sectional view showing the state in which the tip of the metal stopper has reached the metal base material and sparked; Fig. 5 is a cross-sectional view showing the state after the connection is completed, FIG. 6 is a perspective view showing another embodiment of the metal fastener, FIGS. 7 and 8 are conventional examples, and FIG. 7 is a metal fastener FIG. 8 is a partial cross-sectional view showing the state immediately after the connection work of the hard members is started using the same, and FIG. 8 is a cross-sectional view showing the state after the connection is completed. 1, 10... Metal stopper, 2, 12... Head portion, 4, 14... Shank portion, 6, 16... Tip surface, 7, 17... Cutting blade, 8, 18... Protrusion,
30... Board (non-conductive hard member), 31...
...H steel (metal base material).

Claims (1)

[Claims] 1. In a metal fastener that connects the hard member and the metal base material by rotating and penetrating the non-conductive hard member and electrically welding the tip to the metal base material, the head part and the shank part are connected to each other. Consisting of
The tip surface of the shank portion is formed into a flat, non-circular shape, a portion of the periphery of this tip surface constitutes a cutting blade, and a protrusion that serves as an electrical path protrudes from the center of the tip surface. Features: Metal fasteners for connecting hard parts.