JPH0116229B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a self-drilling screw with a stopper used for attaching a relatively soft member such as a heat insulating material to a member made of a thin metal plate. A method for manufacturing a self-drilling screw with a stopper suitable for attaching a soft heat insulating material to a member made of a thin metal plate with a thickness of 1 mm or less, such as a duct for air conditioning equipment installed in We provide combination rolling dies.

Prior Art A fastening component for attaching a relatively soft heat insulating material, etc. to a plate member has a head at one end of the shank, a drill end portion or cone-shaped self-drilling means at the other end, and an excessive In order to prevent tightening, a fin-like, flange-like, or stepped shape having an outer diameter larger than the outer diameter of the threaded part is provided adjacent to the terminal end of the threaded part that is continuous with the self-drilling means and extends to an intermediate position of the shank. A self-drilling screw with a stopper is known (see, for example, Japanese Utility Model Publication No. 47-39159 and Japanese Utility Model Application Publication No. 54-37764).

Problems to be Solved by the Invention However, for the following reasons, conventional self-drilling screws with stoppers of this type cannot be applied to very thin metal plates with a thickness of 1 mm or less, such as the duct described above. Have difficulty.

FIG. 7 shows a state in which a conventional self-drilling screw 30 is screwed into and fastened to a thin metal plate 20 having a very thin plate thickness.
0 has a sharp self-drilling part 33 at the tip of the threaded part 32, and a shaft part 31 having a diameter larger than the outer diameter of the threaded part 32 is connected to the terminal end of the threaded part 32, and the drawing step part It has a structure in which the stopper 36 is used as the stopper 36.

In this case, as is clear from the drawing, only one thread or less of the thread 32a at the end of the threaded portion 32 engages with the thin metal plate 20, and the thread height of this terminal thread 32a decreases in normal thread rolling processing. (because there is less flesh to be raised), the thread is incompletely threaded, and the engagement with the thin metal plate 20 is insufficient. For this reason, the stopper 16 is attached to the thin metal plate 2.
When screwed in until it touches and works, the threaded part 32a
There was a problem in that the bolts easily slipped and the specified fastening force could not be obtained. Also, even if the stopper is 36
Even if the stopper 3 is formed perpendicularly to the axis,
Since it is impossible to roll the threads to the limit of 6, insufficient engagement between the terminal threads 32a and the thin metal plate 20 is unavoidable, and the threads often easily slip, making it impossible to fasten the screws.

The present invention has been made for the purpose of solving the above-mentioned problems, and provides a threaded portion 12.
By adopting a special processing method and forming the stopper 16 provided adjacent to the terminal end of the threaded portion 12 at the same time as the rolling process of the threaded portion 12, the insufficient thread height of the terminal thread 12a of the threaded portion 12 is compensated for and the thread height is increased. This prevents the threaded portion 12 from being extremely reduced, and allows the threaded portion 12 to engage firmly and reliably even with the thin metal plate 20, which has a very thin plate thickness. The present invention provides a method for manufacturing a self-drilling screw with a stopper that has a reliable stopper function by forming a flange-like stopper, and a combination rolling die for use in manufacturing the screw.

Means for Solving the Problems That is, the present invention simultaneously rolls an annular groove 15 on the outer periphery of the shank 11 spaced apart from the terminal end of the threaded portion 12 toward the head 14, at the same time as rolling the threaded portion 12, With a stopper characterized in that by gradually expanding the groove width of the annular groove 15 toward the threaded part 12 side, a flange-like stopper 16 is formed adjacent to the terminal thread 12a of the threaded part 12 using the excess thickness. This is a method of manufacturing a self-drilling screw.

The second invention relates to a combination rolling die for carrying out the above method, and includes a shank 11.
Consisting of thread rolling dies 2, 2 for rolling the threaded portion 12 to an intermediate position, and stopper forming dies 3, 3 stacked on the thread rolling dies 2, 2,
The stopper forming die 3 is spaced apart from the upper end surface 4 of the thread rolling die 2 on the front side in the advancing direction, and gradually moves away from the upper end surface 4 of the thread rolling die 2 as it reaches the rear side.
A protrusion 5 for a configuration having an inclined lower end surface 6 close to
It is characterized by having the following.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. FIG. 1 shows a combination rolling die 1 for carrying out the method of the present invention, and FIG. 2 shows a self-drilling screw 10 with a stopper manufactured using the combination rolling die 1.

The combination rolling die 1 includes a pair of thread rolling dies 2, 2 for rolling the threaded portion 12 to an intermediate position of the shank 11 of the thread blunter 9 to be processed, and a combination rolling die 1 stacked on the thread rolling dies 2, 2. It consists of a stopper forming die 3, 3.

The thread rolling die 2 is the same as a normal one. However, in order to form a sharp conical self-drilling part 13 at the tip of the threaded part 12, the lower part is actually curved, but this is omitted in the drawing.

Further, a head 14 is formed in advance at the upper end of the shank 11 of the screw blank 9, and the lower end of the shank 11 is formed tapered. Note that, as shown by the broken line in FIG. 2, a drill end portion 23 may be provided instead of the conical self-drilling portion 13. In this case, the drill end portion 23 is previously formed at the lower end of the shank 11 before the rolling process.

The stopper forming die 3 has a groove forming protrusion 5 extending along the upper end surface 4 of the thread rolling die 2, and the groove forming protrusion 5 extends from the thread rolling die 2 on the forward side in the advancing direction. An inclined lower end surface 6 that is spaced apart from the upper end surface 4 and gradually approaches the upper end surface 4 toward the rear side.
have.

Shank 11 using the above combination rolling die 1
When rolling is performed, as shown in FIG. A narrow annular groove 1 is formed on the outer periphery of the shank 11 at a location spaced apart from the terminal end toward the head 14.
5 is molded. At this time, since the thread 12a at the end of the threaded portion 12 has a small amount of excess thickness built up from above, it is an incomplete thread with a low thread height as shown in the figure.

As the rolling process progresses, as shown in Figure 4,
An annular groove 15 is formed by the inclined lower end surface 6 of the groove forming protrusion 5.
The width of the groove is gradually expanded toward the threaded portion 12, and as a result, the increased extra thickness forms a flange-like stopper 16 adjacent to the terminal end of the threaded portion 12 with a diameter larger than the outer diameter of the threaded portion 12. At the same time, the threaded portion 12 is further tightened with extra thickness.
The lack of the thread height of the thread 12a at the end is compensated to make the thread 12a a complete thread.

FIG. 5 shows an example in which a heat insulating material 21 is attached to a very thin metal plate 20 using the self-drilling screw with a stopper manufactured as described above, and shows the thread 12a at the end of the threaded portion 12. is firmly and reliably screwed onto the thin metal plate 20, and
A stopper 16 abuts against the thin metal plate 20 to prevent excessive tightening.

Note that if it is necessary to further increase the size of the stopper 16, the groove radius of the annular groove 15 may be increased or
As shown in FIG. 6, the shank portion 11 above the threaded portion 12 may be previously formed to have a larger diameter.

Effects of the Invention As described above, according to the method of the present invention, the intermediate stopper 16 is formed at the same time as the rolling process of the threaded portion 12, and moreover, the excess thickness produced when forming the stopper 16 is used to increase the height of the terminal thread 12a of the threaded portion 12. This can be used to compensate for the lack of thread height and effectively prevent the thread height from decreasing drastically, so it can be firmly and reliably fastened even to a thin metal plate in which only one thread or less is engaged. Therefore, the self-drilling screw with a stopper according to the present invention is suitable for attaching a heat insulating material to a very thin metal plate such as a duct for air conditioning equipment.

Further, the stopper 16 is formed by gradually widening the groove width of the annular groove 15 rolled on the outer periphery of the shank 11 spaced apart from the terminal end of the threaded part 12 toward the head 14 side toward the threaded part 12. A large stopper 16 can be obtained with a shallow groove, and therefore, there is an effect that a large diameter stopper 16 can be formed without reducing the shank strength of the part where the groove is provided.

Further, by using the combination rolling die according to the second aspect of the present invention used to carry out the above method, the above-described self-drilling screw with a stopper can be mass-produced at low cost.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a combination rolling die used in carrying out the method of the present invention, Fig. 2 is a front view of a self-drilling screw with a stopper manufactured by the method of the present invention, and Figs. 3 and 4 show the outline of the manufacturing process. FIG. 5 is a vertical front view showing the usage state of the drilling screw, FIG. 6 is a front view of another embodiment,
FIG. 7 is an enlarged front view of the main parts of the conventional example. 1... Combination rolling die, 2... Thread rolling die, 3... Stopper forming die, 4... Upper end surface,
5... Protrusion for groove forming, 6... Inclined lower end surface, 10...
...Self-drilling screw with stopper, 11...
...Shank, 12...Threaded part, 12a...Terminal thread, 13, 23...Self-drilling part, 14
... Head, 15 ... Annular groove, 16 ... Stopper.

Claims (1)

[Claims] 1. The shank 1 has a head 14 at one end and a self-drilling means 13 or 23 at the other end, and is provided continuously to the self-drilling means 13 or 23 to an intermediate position of the shank 11. In manufacturing a self-drilling screw with a stopper, which is provided with a flange-like stopper 16 adjacent to the terminal end of the threaded part 12 and having a diameter substantially equal to or larger than the outer diameter of the threaded part 12, the steps include rolling the threaded part 12; At the same time, the threaded portion 12
By rolling an annular groove 15 on the outer periphery of the shank 11 spaced apart from the terminal end toward the head 14 side, and gradually increasing the width of the annular groove 15 toward the threaded part 12 side, the threaded part 12 is formed with the extra thickness. A method of manufacturing a self-drilling screw with a stopper, characterized in that a flange-like stopper 16 is formed adjacent to the terminal thread 12a of the screw. 2. A combination rolling die for use in manufacturing the self-drilling screw with a stopper, which includes a thread rolling die 2, 2 for rolling the threaded portion 12 to the intermediate position of the shank 11, and the thread rolling die. The stopper forming die 3 is spaced apart from the upper end surface 4 of the thread rolling die 2 on the front side in the direction of movement and extends toward the rear side. A combination rolling die characterized in that it is provided with a groove-forming protrusion 5 having an inclined lower end surface 6 gradually approaching the upper end surface 4 of the thread rolling die 2.