JPH0334429B2 - - 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) The present applicant has proposed a welding device 20 as shown in FIG.
Developed JP-A-61-266192 (patent application 1986-
No. 109600). To be more specific, the welding device 20 includes a capacitor (welding machine main body) 21 and an automatic driver 24, and the automatic driver 24 has a rotating bit 25. Then, welding is performed using a metal fastener 40 in the shape of a wood screw as shown in FIGS. 8 and 9. For example, board (non-conductive hard member)
When connecting to a steel plate (metal base material), first, the board 30 is stacked on the steel plate 31. One electrode of the capacitor 21 is connected to the steel plate 31 via the contact holder 29, and the other electrode is connected to the rotary bit 25 of the automatic screwdriver 24. Next, the top surface 41 of the head portion 41 of the metal stopper 40 is
Insert the tip 25a of the rotary bit 25 into the locking hole 41b formed in the hole 41b. From this state, the metal stopper 40 is screwed into the board 30 while being rotated by the automatic driver 24, and when the tip 42 of the metal stopper 40 almost reaches the steel plate 31, the capacitor 21 is inserted between them. Electricity is applied to generate a spark between the two, and the metal stopper 4
0 and a part of the steel plate 31 are melted.
As the molten metal 36 solidifies, the metal stopper 40
The tip 42 of the board 30 is welded to the steel plate 31.
is connected to the steel plate 31.

(Problem to be Solved by the Invention) When the steel plate 31 is covered with a coating 32 such as anti-corrosion paint or galvanizing, the metal stopper 40 has a tapered tip 42. , the coating 32 could not be scraped off, and this coating 32 caused welding defects. As a result, the welding between the two was insufficient, and the board 30 could not be reliably connected to the steel plate 31, 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 portion and a shank portion, and the tip surface of the shank portion has a flange passing approximately through the center of the tip surface. The present invention relates to a metal fastener for connecting hard members, characterized in that a part is formed therein.

(Function) A non-conductive hard member is layered on a metal base material. The metal stopper is rotated and the hard member is penetrated while being cut by its flange. Then, the coating on the metal base material is scraped off with the flange on the tip side of the metal stopper. When the flange on the tip side almost reaches the fabric of the metal base material, electricity is passed between the two to melt the tip 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 7.

Reference numeral 1 in FIGS. 1 and 2 is a metal stopper, which connects a board 30 (a non-conductive hard member) and a steel plate 31 (a metal base material). This metal stopper 1 has a head portion 2 and a shank portion 4.
It is composed of. This head portion 2 has an inverted conical shape, and a cross-shaped locking hole 2b is provided on the top surface 2a.
However, a step portion 3 is formed on each conical surface. The distal end surface 5 of the shank portion 4 is not sharp and is substantially flat over a wide area. Continuous collar portions 7a and 7c are formed from the distal end surface 5 of the shank portion 4 to a portion of the circumferential surface 6. The flange 7a on the distal end surface 5 side passes approximately through the center of the distal end surface 5 and extends linearly in the radial direction, and a convex portion 7b having a sharp tip is formed at the center thereof. Further, the flange portion 7c on the peripheral surface 6 side extends linearly along the axial direction of the metal stopper 1.

Reference numeral 20 in FIG. 3 is a welding machine, which electrically welds the metal fastener 1 and the steel plate 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. The automatic screwdriver 24 has a rotary 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 a switch (not shown) which is turned on by a timer (not shown) when the interlocking switch 27 is turned on, and at the same time, the bit 25 is connected to one electrode of the air compressor 28. It is designed to be rotated by compressed air. The clutch 26 is connected to the rotating bit 2.
It is designed to be cut in conjunction with 5. A contact holder 29 is provided at the tip of the other cable 23.

Board 30 using the metal stopper 1 configured as described above.
The process of connecting the steel plate 31 to the steel plate 31 will be explained with reference to FIGS. 3 to 6. Note that the board 30 is
Non-conductive and non-flammable (or flame-retardant) materials such as hard wood chips and cement materials. In addition, the steel plate 31
A coating 32 is provided by galvanizing or painting. The metal stopper 1 is made of a material softer than the steel plate 31.

As shown in FIG. 3, a board 30 is stacked on a steel plate 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 steel plate 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 7b of the collar 7 of the metal stopper 1 into the surface 30a of the board 30. The position of the metal stopper 1 can be easily determined by simply pushing the convex portion 7b into the surface 30a of the board 30. Next, the interlocking switch 27 of the automatic screwdriver 24 is turned ON, and the surface 3 of the board 30 is rotated while the metal stopper 1 is rotated by the rotation bit 25.
Screw in from 0a toward the steel plate 31. At this time, the convex portion 7b of the metal stopper 1 serves as a guide and the board 30 is cut by the flanges 7a, 7c, so the shank portion 4 of the metal stopper 1 passes through the board 30 smoothly. Also, as shown in Figure 7,
The surface 30 of the board 30 is
Since a dish-shaped recess 30b is formed in a, the head portion 2 is accommodated in this recess 30b.

As shown in FIG. 4, the convex portion 7b of the metal stopper 1
When it hits the steel plate 31, the detection circuit closes and starts the timer. Moreover, this convex portion 7b is connected to the steel plate 31.
When the metal fastener 1 penetrates through the coating 32 and hits the fabric of the steel plate 31, it is abraded by the steel plate 31 since it is made of a softer material than the steel plate 31. When the convex portion 7b is worn away, the flange portion 7a approaches the steel plate 31, and the coating 32 is scraped off over a wide range by the flange portion 7a. A predetermined period of time elapses after the protrusion 7b of the metal stopper 1 comes into contact with the steel plate 31 until the flange 7a completely scrapes off the coating 32 and comes into contact with the material of the steel plate 31 over its entire length. After that, the electrode of the capacitor 21 and the rotating bit 25 are electrically connected by the above-mentioned timer, and the capacitor is connected via the cable 22, the rotating bit 25, the metal stopper 1, the steel plate 31, the contact holder 29, and the cable 23. 21 is closed, the electricity stored in the capacitor 21 instantly flows, and a spark is generated between the collar 7a and the steel plate 31, as shown in FIG. At this moment, due to the rotation of the metal stopper 1, the center part of the flange part 7a moves less relative to the steel plate 31 than the both sides thereof, so that sparks can always be generated at the center of the flange part 7a. Note that the spark time is approximately 4/1000 seconds. This spark causes the flange 7a of the shank portion 4 of the metal stopper 1 to
Then, the tip end surface 5 and a part of the steel plate 31 are melted.
After the spark starts, the metal stopper 1 further moves forward to narrow the gap between the tip end face 5 and the steel plate 31, and fills the gap between them with the molten metal 35. When this molten metal 35 solidifies, the rotational torque of the metal stopper 1 increases and the clutch 26 is disengaged, so that the rotating bit 25 of the automatic screwdriver 24 no longer turns. After this, the interlocking switch 27 is turned OFF. As a result, as shown in FIG. 6, as the molten metal 35 solidifies, the tip of the shank portion 3 of the metal stopper 1 is welded to the steel plate 31, and the board 30 can be easily connected to the steel plate 31. .

Since the flange part 7a of the metal stopper 1 completely scrapes off the coating 32 of the steel plate 31, the tip of the shank part 4 of the metal stopper 1 can be reliably welded and fixed, and the board 30 can be fixed to the steel plate 31. 31.

This invention is not limited to the above-mentioned embodiments, and various embodiments are possible. For example, it can be applied to the case where plywood (a non-conductive hard member) is connected to a steel plate.

(Effects of the Invention) As explained above, in the present invention, the flange on the tip side of the metal stopper can completely scrape off the film coated on the metal base material, and the film does not get in the way of welding. It never becomes. As a result, the tip of the metal stopper can be reliably welded to the metal base material, and the non-conductive hard member can be reliably connected to the metal base material. Moreover, since the metal stopper is penetrated while the flange is cutting the hard member, the hard member is not cracked.

[Brief explanation of the drawing]

The drawings from FIG. 1 to FIG. 7 show an embodiment of the present invention, and FIG. 1 is a front 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 partially enlarged cross-sectional view showing the state in which the coating of the metal base material is scraped off with the tip of the metal stopper; FIG. The figure is a partially enlarged sectional view showing the state in which the tip of the metal stopper reaches the fabric of the metal base material and sparks, Figure 6 is a partially enlarged sectional view showing the state after the connection is completed, and Figure 7 is the connection completed Figures 8 and 9 show the subsequent state, and Figure 8 shows the conventional example, and Figure 8 is a partial cross-sectional view of the state immediately after the work of connecting the hard members using metal fasteners has started. , FIG. 9 is a sectional view showing the state after the connection is completed. 1...Metal stopper, 2...Head part, 4...
Shank part, 5... Tip surface, 7a... Flange part, 30
...Board (non-conductive hard member), 31... Steel plate (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
A metal fastener for connecting a hard member, characterized in that a flange section passing approximately through the center of the distal end surface of the shank section is formed on the distal end surface of the shank section.