JPH10131932A - Self drilling tapping screw for metal thin plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self drilling tapping screw capable of screwing by decreasing deflection as small as possible of a workpiece relating to the workpiece of thin metal plate. SOLUTION: In a leg part 3 continued from a head part 2, a parallel barrel part 10 of the same diameter is formed, in a tip end of this barrel part 10, a cone-shaped sharp tip part 20 gradually decreasing a tip end diameter is provided, in the periphery of these barrel part 10 and sharp tip part 20, a thread ridge 4 is formed, by obtaining a self drilling tapping screw formed with a cutting edge 23 to a screwing direction in the sharp tip part 20 to cut a guide groove 22, necessity for work always drilling a prepared hole in a workpiece by a drill is eliminated, a work time and man-hours are decreased. Even in the case of using many screws in a product, fatigue of a worker is reduced, a work environment is extremely improved. Further, in the case of use in a relatively thin metal plate, since a screw bites in the workpiece in a short time, deflection of the workpiece is reduced, a fine view of a product is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention allows a self-tapping screw to be screwed in as a series of operations while drilling a pilot hole in a work and forming a female screw without previously drilling a pilot hole in the work. Especially with self-tapping screws
The present invention relates to a self-drilling tapping screw developed for thin metal sheets.

[0002]

2. Description of the Related Art Conventionally, when a tapping screw is screwed into a metal thin plate, a prepared hole for screwing the screw is drilled in advance using a tool such as a drill in the metal thin plate work. By screwing a self-tapping screw into the prepared hole, a female screw is formed and screwed into the work by itself. In such a case, as shown mainly in FIG. 3, the thread 104 is formed up to the tip of the leg 103, and the leg 103 has a tapered shape in which the tip 120 has a smaller diameter from the tip to the tip. A formed tapping screw is used, and the tapping screw is screwed into a prepared hole 131 of the work 130 having a diameter smaller than the thread diameter, for example, an effective diameter or less.

In the case where the pilot hole 131 is not formed in the work 130, for example, Japanese Patent Publication No. 50-57
No. 77 is used. This is because, as shown in FIG.
4 is a drill tapping screw in which a tapered thread 104 is continuously formed, and a drill portion 121 having a diameter smaller than the diameter of the body is provided at the tip thereof. Using this, the work 130 is continuously drilled and screwed into the work 130.

[0004]

However, when such a conventional tapping screw is used, a drill hole is always drilled in the work until the screw of the work is screwed in until the screw is screwed. The work must be performed, and therefore, a separate work of forming a pilot hole in the work is required, and the work time and man-hours are increased. There is no problem when using only a small amount of such tapping screws in the product.However, when there are many screws to be used in the product, the operator drills a hole in the work with this drill, and The number increases according to the number, and therefore, the fatigue of the worker is likely to occur, and the working environment is extremely deteriorated. Further, when using a relatively thin metal plate, the work is bent during the operation with the drill, so that the appearance of the product is impaired.

[0005] Next, in another conventional example, a pilot hole is made in the work with a drill portion at the tip of the screw, and a female screw is formed continuously with the prepared hole, and the screw is screwed. Since the cutting edge of the drill portion has an obtuse angle, the biting of the drill portion to the work is poor, and therefore, the work is bent by the pressing force of the tip of the drill portion, and dents are generated, resulting in defective products. And other issues.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a self-drilling tapping screw which can solve the above-mentioned problem and can screw in a work having a relatively thin metal plate while minimizing the bending of the work.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a leg 3
A parallel body 10 having the same diameter is formed on a leg 3 continuous from the head 2 by using a tapping screw including a head 2 integrally formed with a diameter larger than the diameter of the leg at one end of the leg 3. At the tip of the body 10, there is provided a conical pointed tip 20 whose tip diameter becomes gradually smaller, and a thread 4 is formed on the outer periphery of the body 10 and the pointed tip 20. 2
Guide groove 2 in which cutting blade 23 is formed in screwing direction 0
Achieved by providing a self-drilling tapping for sheet metal with a cut-out of 2.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 denotes a self-drilling tapping screw including a head 2 and a leg 3,
A head 2 having a diameter larger than the diameter of the leg 3 is integrally formed at one end of the leg 3. On the head side of the leg 3, a parallel trunk 10 having the same leg diameter is formed. The trunk 10 has a conical pointed tip 20 whose diameter gradually decreases toward the tip. The torso 10 and the pointed tip 20
Is formed with a thread 4 continuously.

As shown in FIG. 2, the conical pointed portion 20 has two guide grooves 22 on opposite sides of the center line of the tip along the axis and gradually as the distance from the tip of the screw 1 increases. The guide groove 22 has a cutting edge 23 formed on the outer edge of the guide groove 22 on the forward side in the screwing direction to form a drill portion 21. The cutting blade 23 is formed along the cross section of the screw thread 4 formed on the outer periphery of the pointed part 20, and drills a pilot hole (not shown) in a work (not shown) and simultaneously forms a female screw (not shown). Are also formed.

Using the self-drilling tapping screw 1 obtained as described above, pressing the screw 1 against a work of a relatively thin metal plate and screwing the screw 1 in the screwing direction, the screw 1 is initially screwed. A drill hole is formed in the pointed portion 20 of the screw 1 to drill a pilot hole in the work. Subsequently, a pilot hole is formed and a female screw is formed in the pilot hole, and the pilot hole is expanded to a predetermined size.

When the preparation of the prepared hole in the drill portion 21 of the pointed portion 20 is completed in this manner, the thread 4
The screw 1 is screwed into the work while a female screw is formed. During this operation, the tip of the pointed portion 20 does not slide on the work, and the cutting blade 23 of the drill portion 21 bites into the work in a short time, so that the work is only slightly bent and the screwing position is not increased. No deviation occurs.

[0012]

As described above, according to the present invention, the leg 3
A parallel body 10 having the same diameter is formed on a leg 3 continuous from the head 2 by a tapping screw comprising a head 2 integrally formed with a diameter larger than the diameter of the leg at one end of the leg 3. At the tip of the body 10, there is provided a conical pointed tip 20 whose tip diameter becomes gradually smaller, and a thread 4 is formed on the outer periphery of the body 10 and the pointed tip 20. 20 is a self-drilling tapping screw for a thin metal plate in which a guide groove 22 in which a cutting blade 23 is formed in the screwing direction is cut. This eliminates the need for opening work, and reduces work time and man-hours. Also,
Even when many screws are used in the product, the operator does not have to drill a hole in the work, so that the fatigue of the operator is reduced and the working environment is extremely good. Furthermore,
When used on a relatively thin metal plate, the screw bites into the work in a short time, so that the bending of the work due to the screwing operation is reduced, and specific effects such as improvement in the appearance of the product are obtained.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is an enlarged bottom view of FIG.

FIG. 3 is a front view showing a use state of a conventional example of the present invention.

FIG. 4 is a front view showing a use state of another conventional example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Self-drilling tapping screw 2 Head 3 Leg 4 Thread 10 Body 20 Sharp point 21 Drill 22 Guide groove 23 Cutting blade

Claims (1)

[Claims] 1. A tapping screw comprising a leg 3 and a head 2 integrally formed at one end of the leg 3 with a diameter larger than the diameter of the leg, wherein the diameter of the leg 3 continuous from the head 2 is the same. Are formed in parallel with each other, and at the tip of the body 10, there is provided a conical pointed portion 20 whose tip diameter gradually decreases.
A self-drilling tapping screw for a thin metal plate, wherein a thread 4 is formed on the outer periphery of a pointed part 20 and a guide groove 22 having a cutting blade 23 formed in the screwing direction is cut in the pointed part 20. .