JPH0750576Y2 - Self-drilling screw with reamer - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-drilling screw with a reamer for fixing a siding plate or the like to a metal frame or the like.

[0002]

2. Description of the Related Art Conventionally, a self-drilling screw is convenient in that a screw hole is cut and tapped continuously, and screw fastening is performed in a series of operations, and various self-drilling screws are provided. ing.

By the way, the expansion of the use range of self-drilling screws is remarkable especially in the field of construction. For example, the use of a self-drilling screw is also desired for fixing a non-metal mounting member such as a siding plate or a ground plate to a metal mounted member such as a metal frame containing C-shaped steel.

However, when fixing such a non-metallic mounting member to a metallic mounted member, it is not possible to use an ordinary self-drilling screw that is generally used.
That is, as shown in FIG. 2 (A), a normal general self-drilling screw 1 simply extends a drill portion 3 at a front end of a shank 2 with a thread (hereinafter, this screw will be referred to as a screw). Known example). Therefore, while the self-drilling screw 1 is being screwed into the non-metallic mounting member 4, a desired self-drilling action and tapping action can be expected, but when the drill section 3 reaches the metallic mounted member 5, the self-drilling action is performed there. The drill screw 1 does not enter and stops. Since the pitch of the drill portion 3 is larger than the pitch of the screw thread even if the drill portion 3 tries to enter the metallic member 5 to be mounted at a predetermined pitch, the non-metallic mounting member 4 will be covered. This is because the thread that is screwed and locked in the axial direction does not follow the thread.

Therefore, in order to improve this point, FIG.
A self-drilling screw 6 with a reamer as shown in (1) has been proposed (hereinafter this screw is referred to as a conventional example). The self-drilling screw 6 according to the conventional example is similar to the known example in that the drill portion 3 is extended to the front end of the shank 2 with a thread, but is located between the shank 2 and the drill portion 3. hand,
A reamer blade 7 protruding laterally is provided. According to this conventional example, as soon as a pilot hole is formed in the non-metallic mounting member 4 by the drill portion 3, the pilot hole is cut by the reamer blade 7 to have a larger diameter, and the following screw is loosely inserted. Hole 7
a is formed. Therefore, when the drill portion 3 penetrating the non-metallic mounting member 4 reaches the metallic mounted member 3, the screw thread is in a state where it can freely enter through the reaming hole 7a. According to the pitch, the metal attachment member 3 can be inserted. Since the reamer blade 7 is formed thin, it is broken when it penetrates the metal member 3 to be attached, and is automatically separated and removed from the screw.

Incidentally, the self-drilling screw with a reamer according to the above-mentioned conventional example also has a problem to be further improved. That is, the non-metallic mounting member 4 is expected to be various building members such as the above-mentioned siding plate, but recently, for such building members, molded articles such as foam concrete plates are often used, and the drill portion 3 is used. Due to this, powdery cutting chips are produced when the material is cut and enters. However, in a self-drilling screw with a reamer according to a conventional example as shown in FIG. 2B, a shank blank 2a for forming a reamer blade 7 is interposed between the drill portion 3 and the shank 2 with a thread. Therefore, the drill part 3 exists independently. In other words, the rear end of the vertical groove 8 in the drill portion 3 is closed by the shank blank 2a. For this reason, the powdered cutting dust of the non-metallic mounting member 4 that has been cut is not discharged from the vertical groove 8 of the drill portion 3, but is restrained and bound inside the vertical groove 8.
It not only lowers the drill function thereafter, but also increases the rotation resistance of the screw.

[0007]

[Problems to be Solved by the Invention]
It is an object to eliminate the disadvantages while maintaining the advantages of the conventional self-drilling screw with a reamer as shown in (B).

Therefore, in order to eliminate the above disadvantages, as shown in FIG. 2 (C), a reamer blade 7 is provided on a side portion of the drill portion 3 to cut the non-metallic mounting member 4 in powder form. It is advantageous to construct that the debris is easily discharged from the longitudinal groove 8 of the drill portion 3 toward the shank 2 (hereinafter this screw will be referred to as a comparative example).

In this comparative example, as shown in FIG. 3, when the vertical groove 8 is forged in the drill portion 3 by a pair of punch dies, the reamer blade 7 is simultaneously formed by the cavity formed in the punch dies. That is, the cutting surface 9 is formed by forming the vertical groove 8, and the cutting edge 1 is formed on the side edge of the cutting surface 9.
When forming 0, the cutting edge 1
The reamer blade 7 extending from 0 to the same plane is forged. Therefore, the cutting surface 9 and the reamer blade 7 are located on the same plane P.

By the way, the comparative example shown in FIGS. 2 (C) and 3 is different from the conventional example shown in FIG. It is relatively excellent in that it allows chips to be easily discharged from the vertical groove 8 to the shank 2, but when actually tested, the rotation resistance is greatly reduced compared to the conventional example. No,
Requires strong torque for screwing.

Regarding this point, according to the analysis of the present inventor, the following was found in the comparative example. That is, the drilling action of the drill portion 3 is such that, when the drill portion 3 is rotated and made to enter, the non-metallic mounting member 4 is first cut by the cutting edge 10, and the inner periphery of the cut hole is continuously cut. It is ideal to ream by 7. However, in the case of the comparative example, since the reamer blade 7 is located on the same line of the cutting edge 10 and immediately above,
When the drill part 3 rotates and enters the thrust direction at the same time,
With respect to the non-metallic mounting member 4, the reamer blade 7 directly cuts into the uncut portion beyond the portion previously cut by the cutting edge 10. Therefore, the reamer blade 7 bears not only the intended reaming action but also the drilling action by itself, and as a result, causes a great rotational resistance.

Further, as described above, the reamer blade 7 is provided with the cutting edge 1.
Since the drilling action is performed on the same line as 0, before the powdery cutting chips generated by the cutting edge 10 are discharged from the rear end of the vertical groove 8, the reamer blade 7 holds the cutting chips and performs the next cutting. To start. For this reason, the discharge of cutting waste is hindered by the reamer blade 7, which causes a factor that cannot reduce the rotational resistance.

Further, since the reaming blade 7 is formed so as to be flush with the cutting surface 9 when it is forged at the same time when the drill portion 3 is formed by a punch die, the flow of metal material is not sufficient, There is a great risk that the reamer blade 7 may be carelessly formed to be thin. Then, as described above, the reamer blade 7
Receives an excessive load due to its own drilling action,
The reamer blade 7 may be broken while the non-metallic mounting member 4 before the drill portion 3 reaches the metallic mounted member 5 is being advanced.

[0014]

Means for Solving the Problems The present invention provides a self-drilling screw with a reamer that solves the above-mentioned problems. The first means is to extend the front end of a shank with a thread. The drilled portion includes a body that extends in the axial direction from the shank and a pointed portion that protrudes forward from the body, and the cutting surface is formed by two longitudinal grooves that are formed to face each other in the radial direction of the body. And a self-drilling screw formed by forming a cutting edge extending rearward from a sharp edge portion of a side edge of the cutting surface,
A recess that communicates with the vertical groove by recessing near the rear end
From the bottom of the recess to the side of the drill
The point is that the protruding reamer blade is extended .

Further, the present invention is configured as a second means in that the cutting edge is provided near the rear end of the cutting edge.
A recess formed by recessing the surface and a body facing the recess.
And a recessed portion formed by crushing the peripheral surface of the
The point is that it is formed by forging a reamer blade between it and the recess .

[0016]

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a main part of the self-drilling screw 11 with a reamer. Although not shown, the screw 11 is integrally provided with a head portion having a tool engaging portion at the tail end of the shank 13 with the thread 12.

A drill portion 14 extends from the front end of the shank 13, and the drill portion 14 includes a body 15 extending axially from the shank 13 and a tip portion 16 projecting forward from the body 15. Is equipped with.

The body 15 has two diametrically opposed members.
The longitudinal grooves 17, 17 of the strip are formed in the axial direction, and each of the longitudinal grooves 17 constitutes a cutting surface 18, and a cutting edge 19 is formed at a side edge of the cutting surface 18. The cutting edge 19 is continuous with the cutting edge 19 of the tip portion 16 and extends axially rearward from the cutting edge 19. The drill portion 14 having such a configuration is
It is integrally formed by forging using a pair of punch dies.

After forging the drill portion 14,
By using a pair of punch dies again, the vertical groove 1
A reamer blade 21 protruding laterally of the body 15 is formed in the vicinity of the rear end of the body 7.

A pair of reaming blades 21 are provided in the vicinity of the cutting edges 19 and 19, but as shown in FIGS. It is eccentric to the side. That is, it is offset from the plane P extending from the cutting surface 18 to the cutting edge 19 with a distance S in the circumferential direction. In the case of the illustrated example, the displacement amount is relatively small, but the displacement amount S of the reamer blade 21 can be displaced from the cutting edge 19 up to about 45 degrees with respect to the center of the drill portion 14. .

Corresponding to the offset portion S, the body 15 is provided with a recess 22 which communicates with the vertical groove 17 by recessing the vicinity of the rear end of the cutting surface 18. Further, facing the concave portion 22, a concave portion 23 is formed on the peripheral surface of the body 15 in the circumferential direction.
The reamer blade 21 is formed between the recess 2 and the recess 23 by forging. That is, the recess 2 is formed by a pair of punch dies.
While molding 2 and the recessed portion 23, the reamer blade 21 is molded by the metal material crushed by this.

The self-drilling screw 11 with a reamer according to this embodiment is screwed from the non-metallic mounting member 4 to the metallic mounted member 5 as in the comparative example shown in FIG. While entering the mounting member 4, the perforations formed by the drill portion 14 are reamed by the reamer blade 21 so that the thread 12 of the shank 13 is not screwed into the non-metallic mounting member 4. Therefore, when the drill portion 14 penetrates the non-metallic mounting member 4, the drill portion 14 pierces the metal mounted member 5 and screws it.

Therefore, according to this embodiment, the problems of the above-described comparative example could be solved as follows.

The drill part 1 is being inserted into the non-metallic mounting member 4.
In No. 4, the material is cut by the cutting edge 19, and then the reamer blade 21 is guided to the cutting portion to ream. That is, since the reamer blade 21 is displaced S to the rear side with respect to the preceding cutting edge 19 with respect to the rotation direction of the screw, when the drill portion 14 enters in the thrust direction at the same time as the rotation, the reamer blade 21
Follows the trajectory of the cutting edge 19 and has already reached the cutting edge 19
Ream the drilled part cut by. Therefore,
Unlike the comparative example described above, the reamer blade 21 does not drill the uncut portion of the material beyond the cutting edge 19,
As a result, we succeeded in significantly reducing the rotational resistance as compared with the comparative example.

Further, when the non-metallic mounting member 4 is cut into the drill member 14 and enters, the powdery cutting chips generated by the cutting edge 19 are temporarily held in the vertical groove 17,
As the drill portion 14 advances in the thrust direction, the recess 22
It is easily discharged toward the shank 13 via the. That is, in the case of the above-described comparative example, the powdery cutting chips are held by the reamer blade before being discharged from the rear end of the vertical groove, whereas according to the present embodiment, the deviation of the reamer blade 21 is caused. The position S not only prevents the clogging of cutting debris but also allows the cutting debris to escape from the vertical groove 17 into the concave portion 22, which allows the cutting debris to be dispersed and discharged smoothly, thereby reducing the rotational resistance. Contribute.

Further, as described above, when the recessed portion 22 and the recessed portion 23 are formed by the pair of punch dies, and the reamer blade 21 is formed by the metal material crushed by the recessed portion 22 and the recessed portion 23, the metal material is moved toward the palm direction. The reamer blade 21 can be forged by the flow of meat from both sides.
Has excellent mechanical strength. Further, as described above, the reamer blade 21 is configured so as not to receive an excessive load as much as possible, and thus the reamer blade 21 is being inserted into the non-metallic mounting member 4 as in the comparative example described above. Is not broken.

[0029]

According to the present invention , since the reamer blade 21 bears only the reaming action and hardly the drill action, the rotation of the drill portion 14 during the screwing onto the non-metallic mounting member 4 is performed. This has the effect of reducing the resistance and enabling screwing with an appropriate rotation torque.

According to the present invention as set forth in claim 1 , the powdery cutting chips produced by the cutting edge 19 are followed by the reamer blade 21.
There is no risk of being caught by the shavings, and moreover, the particles are preferably dispersed by escaping from the vertical groove 17 into the concave portion 22 and are easily discharged toward the shank 13 through the concave portion 22. It is possible to prevent the rotation resistance from increasing due to wearing and to maintain the sharpness of the drill portion 14 in a good condition.

According to the second aspect of the present invention, the reamer blade 21 is forged by the recesses 22 and the recessed portions 23 formed by sandwiching the reamer blade 21 by the flow of meat from both sides of the metal material in the palm direction. Since the reamer blade 21 can be molded, the reamer blade 21 has excellent mechanical strength, and the reamer blade 21 does not accidentally break during the insertion of the non-metallic mounting member 4.

[Brief description of drawings]

1A and 1B show a main part of one embodiment of the present invention, FIG. 1A is a side view, FIG. 1B is a front view, and FIG. 1C is a sectional view taken along line XX.

FIG. 2 shows a prior art, (A) is a front view of a known example,
(B) is a front view of a conventional example, (C) is a front view of a comparative example.

3A and 3B show a drill portion of the comparative example, FIG. 3A is a side view, FIG. 3B is a front view, and FIG. 3C is a sectional view taken along line YY.

[Explanation of symbols]

 4 Non-metal mounting member 5 Metal mounted member 11 Self-drilling screw with reamer 12 Thread 13 Shank 14 Drill part 15 Body 16 Pointed part 17 Vertical groove 18 Cutting surface 19 Cutting edge 20 Cutting edge 21 Reamer blade 22 Recess 23 Admission

Claims (2)

[Scope of utility model registration request] 1. A drill portion extending to the front end of a threaded shank comprises a body extending axially from the shank and a pointed portion projecting forward from the body. The drill portion extends in the radial direction of the body. A self-drilling screw comprising a cutting surface composed of two longitudinal grooves formed so as to face each other, and a cutting edge extending rearward from a sharp edge portion of a side edge of the cutting surface. A self-drilling screw with a reamer, characterized in that a recess communicating with the vertical groove is formed by recessing the vicinity of the rear end, and a reamer blade protruding laterally of the drill from the bottom of the recess is provided. . 2. In the vicinity of the rear end of the cutting edge, a recessed portion formed by recessing the cutting surface and a recessed portion formed by crushing the peripheral surface of the body facing the recessed portion are formed, and the recessed portion and the recessed portion are formed. Claim characterized by being formed by forging a reamer blade between and
Item 1. A self-drilling screw with a reamer according to Item 1 .