JPH07158170A - Anchor plate mount structure and mount screw thereof - Google Patents

Abstract

PURPOSE:To provide a mount structure wherein a self-drill screw having good workability, high tightening capability and pull-out strength is used when an anchor plate is mounted and secured to an extrusion-molded cement board, and to provide a screw which can be used in the mount structure. CONSTITUTION:The length L1 of a drill and the length L2 of a shank in a screw is determined, with respect to the thickness T of a mount wall and the depth D of a hollow section of a cement board, by the equations: T<=L1, T1<=L2, and L1+L2<=T+D. And a blade diameter K of the drill, crest diameter M of threads, root diameter R of threads, and pitch P of threads, in the screw, are determined by the equations: R<=K, M/K<=1.25, and 0.31<=P/M<=0.58.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for mounting an anchor plate on an extruded cement plate used as a wall material for construction and a mounting screw for the mounting structure.

[0002]

2. Description of the Related Art Conventionally, an ALC board has been known as a building wall material, but in recent years, an extruded cement board has become a commercial product under a trademark such as "Mace board" or "Asrock board". Is offered as.

Such an extrusion-molded cement board (hereinafter simply referred to as a cement board) is a panel-shaped one formed by extruding mortar mixed with a fibrous tie material such as asbestos. Since it has high strength, it can be configured to have a thin plate thickness, and since it has low water absorption, it does not require waterproofing, and it is expected that it will continue to spread in the future.

By the way, when a cement board is used as a building wall material, a method of attaching an anchor board to the cement board in advance at the site and fixing the anchor board to a steel frame or the like when installing the wall material at a predetermined place is adopted. Has been done. Also,
BACKGROUND ART In order to connect wall materials in a T shape and to connect required building materials to the wall materials, work of attaching an anchor plate to a predetermined portion of a cement plate is performed.

Therefore, conventionally, when attaching an anchor plate to a cement plate, it is necessary to preliminarily form a pilot hole in both the anchor plate and the cement plate, and to connect and fix both with a bolt and a nut through the pilot hole. Has been done.

[0006]

In the above-mentioned prior art,
Both the anchor plate and the cement plate must be pre-drilled, which complicates the work and cannot shorten the work time.

Therefore, the inventor of the present invention has found that the use of so-called drill screws makes it possible to eliminate the need for prepared holes in the cement plate and quickly attach and fix the anchor plate to the cement plate. Such a drill screw is provided with a drill at the tip of a shank with a thread extending from the head, and the applicant of the present invention supplies various products to the market.

However, the present inventor repeated an experiment to attach and fix the anchor plate to the cement plate using various commercially available drill screws, but none of them obtained satisfactory results.

First, when the drill length is smaller than the wall thickness of the cement plate, the thread of the shank enters the drill hole before the drill penetrates the cement plate, which causes a state in which the screw cannot be advanced. To do. This is because the cutting speed of a cement plate with a drill is relatively slow because it involves a great amount of resistance, but when a screw enters the hole and starts tapping, thrust is generated due to the rotation of the screw. .

Secondly, since a general drill screw is intended to fix the steel plates to each other, the thread diameter of the thread is formed to be large with respect to the diameter of the drill blade, but the dimensional difference is not significant. Is taken into consideration. Normally, when the thread diameter M of the screw thread is 6 mm, the blade diameter K of the drill is 5 mm, and M / K =
1.2. This is because when the value of M / K is large when the iron plate is screwed forward while tapping as in the conventional case, the screwability is poor and the engaging portion between the screw head and the rotary tool is crushed. However, when such a conventional drill screw is screwed onto the cement plate which is the object of the present invention, the thread diameter M with respect to the blade diameter K is relatively small,
It has been found that although a good tapping action is obtained, a so-called screw stupid state is brought about with a low torque. This is because the cement plate has a lower particle density and a weaker particle bonding force than the iron plate.

Thirdly, in designing the drill screw, it is known that the smaller the pitch of the thread is, the more the pull-out strength after screwing is improved. It has been found that when the plate is screwed while tapping, the cutting powder is discharged poorly and the groove of the screw thread is clogged with the cutting powder.

[0012]

The present invention has achieved an anchor plate mounting structure and a mounting screw that solve the above-mentioned problems through repeated experiments and exploration from a theoretical point of view.

Therefore, the anchor plate mounting structure of the present invention employs a means in which the cement plate is attached to the extrusion-molded cement plate by forming the adhered portion into a hollow structure to provide a depth. A hollow portion having D and an adherend wall having a wall thickness T facing the hollow portion, and a screw screwed to the adherend wall through a hole of the anchor plate extends from the head. A self-drilling screw having a drill at the tip of the shank with screw thread, and the length L1 of the drill and the length L2 of the shank are set to the wall thickness T of the adhered wall and the hollow portion of the adherend. For depth D, T ≦ L
1 and T ≦ L2 and L1 + L2 ≦ T + D, and the screw has a drill blade diameter K, a thread thread diameter M, a thread root diameter R, and a thread pitch P. R ≦ K, M / K ≦ 1.25, and 0.31 ≦ P / M ≦ 0.
58.

Further, the place where the mounting screws in the anchor plate mounting structure of the present invention are means is a screw for mounting the anchor plate on the extruded cement plate,
The screw constitutes a self-drilling screw provided with a drill at the tip of a shank with a thread extending from the head, and the length L1 of the drill and the length L2 of the shank are defined as the wall thickness T of the adhered wall of the cement board. On the other hand, T ≦ L1 and T ≦ L2, and the screw has a blade diameter K of the drill, a thread diameter M of the thread, a root diameter R of the thread, and a pitch P of the thread. R ≦ K, M / K ≦ 1.25, and 0.31 ≦ P / M ≦ 0.
58.

[0015]

Embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, an extrusion-molded cement board 1 is formed into a panel shape by extruding mortar mixed with a fibrous tie material such as asbestos, and is a solid board. The adhered portion 3 for attaching and fixing the anchor plate 2 is formed into a hollow structure without forming a hollow shape, and the hollow portion 4 and the adhered wall 5 facing the hollow portion 4 are formed. As shown in FIG. 3, the hollow portion 4 has a depth D with respect to the screw advancing direction described later, and the adherend wall 5 has a thickness T.
Have. Therefore, the anchor plate 2 is attached and fixed to the adherend 3 with the screw 6.

As shown in FIG. 2, the screw 6 is provided with a head 7 that is engaged with a rotary tool such as an electric screwdriver, a shank 8 extending from the head 7, and a tip of the shank 8. A self-drilling screw integrally provided with the installed drill 9 is constructed. A flange seat 10 is provided between the head 7 and the shank 8.
And the shank 8 is formed with a thread 11. The drill 9 has a pair of grooves 1 provided so as to be opposed to the peripheral portion.
Blades 13 and 13 are formed on the side edge of No. 2.

By the way, for the screw 6, the length of the drill 9 is L
1. When the length of the shank 8 is L2, T ≦ L1 and T ≦ L2, and L1 + L with respect to the depth D of the hollow portion 4 and the wall thickness T of the adherend wall 5 in the cement plate 1 described above.
2 ≦ T + D. In the illustrated embodiment, when T of the cement board 1 is 15 mm and D is 30 mm, L1 of the screw 6 is 15 mm and L2 is 30 mm, and T = L
1 and D = L2, it is preferable that T <L1.

Therefore, as shown in FIG.
When attaching and fixing the anchor plate 2 to the adherend 3 using, it is not necessary to form a prepared hole in the adherend wall 5 in advance, and the anchor plate 2 is superposed on a predetermined part of the adherend wall 5, When the drill 9 of the screw 6 is erected on the surface of the adhered wall 5 through the hole of the anchor plate 2 and rotated, the drill 9 pierces the anchor plate 2 through the adhered wall 5 while cutting it. At this time, since the thread 11 does not enter the wall 5 until the drill 9 completely penetrates the wall 5, the thread 11 causes the thrust as described above to prevent the thread 11 from being screwed or the female thread. There is no such thing as collapsing. In other words, after the drill 9 penetrates the adhered wall 5 and completes the perforation, the screw 11 enters the perforation and starts tapping, so that the screw 6 suitably enters the adhered wall 5. .

Subsequently, as shown in FIG. 3B, the screw 6
If the thread is inserted while rotating,
Through the hole, the screw is advanced while tapping the perforation of the adherend wall 5, and the flange plate 10 of the head 7 presses the anchor plate 2 to complete the fastening. At this time, as described above, L1 + L2
Since ≦ T + D, the tip of the drill 9 does not hit the facing wall 14 of the hollow portion 4, and the fastening work is completed well.

By the way, a screw 6 which is a self-drilling screw
2 is screwed into the cement plate 1, as shown in FIG. 2, the blade diameter K defined by the blades 13 of the drill 9 in the screw 6, the mountain diameter M of the thread 11, the valley diameter R, and the pitch P. Relationship is extremely important.

First, regarding the relationship between the blade diameter K and the mountain diameter M, the following facts were found as a result of conducting the following experiments 1 and 2 by actually screwing a screw into a cement plate.

[Experiment 1] An experiment was carried out by changing only the blade diameter K using a screw in which the peak diameter M was 8.0 mm, the valley diameter R was 6.2 mm, and the pitch P was 4.5 mm. The results are shown in Table 1 below. According to this, the blade diameter K
The larger the diameter, the larger the diameter of the hole formed by the drill 9, and the better the screwing of the screw thread 11, but on the other hand, the shallower engagement by tapping the screw thread reduces the screw back torque. , The tapped female screw easily collapses, leading to a screw stupid state. According to this Experiment 1, it was found that the screw torque was extremely reduced when M / K was less than 1.25. When the blade diameter K is smaller than the root diameter R, that is, when K <R,
The shank 8 of the screw cannot enter the hole formed by the drill 9.

[Table 1]

[Experiment 2] An experiment was carried out by changing only the blade diameter K using a screw in which the peak diameter M was 6.0 mm, the valley diameter R was 4.5 mm, and the pitch P was 2.5 mm. The results are shown in Table 2 below. Also in this case, as in Experiment 1, the larger the blade diameter K, the better the screwing of the screw thread 11, but the smaller the screw back torque becomes. Also in this Experiment 2, it was found that the screw back torque extremely decreased when M / K was less than 1.25.
When the blade diameter K is smaller than the root diameter R, that is, when K <R, the shank 8 of the screw cannot enter the hole formed by the drill 9.

[Table 2]

As shown in Tables 1 and 2 above, M / K
From the experimental results 1 and 2, the numerical value of R ≦ K
Assuming that M / K ≦ 1.25,
Both the screwability to the cement board and the screw torque can be satisfied.

Next, regarding the relationship between the mountain diameter M and the pitch P,
As a result of conducting the following experiments 3 and 4 by actually screwing the screws into the cement plate, the following facts were found.

[Experiment 3] Only the pitch P is changed by using a screw in which the blade diameter K of the drill is 6.3 mm, the thread diameter M of the screw is 8.0 mm, and the root diameter R is 6.2 mm. Experimented by. The results are shown in Table 3 below. According to this, when the pitch P exceeds a certain value, the drawing strength becomes extremely poor. Also, in general, the pitch P
If the value is made smaller, the pull-out strength is improved, but if it is less than a certain value, screwing becomes impossible. This is because if the pitch P is too small, the cutting powder generated by tapping the screw thread will be discharged poorly, and the groove of the screw thread will be clogged with the cutting powder. Therefore, according to this experiment 3, P
/ M is in the range of 0.31 to 0.56, and therefore 0.31 ≦
It was found that P / M ≦ 0.56 was good.

[Table 3]

[Experiment 4] Only the pitch P is changed by using a screw in which the blade diameter K of the drill is 4.8 mm, the thread diameter M of the thread is 6.0 mm, and the root diameter R is 4.5 mm. Experimented by. The results are shown in Table 4 below. Even in this case, if the pitch P exceeds a certain value, the pulling strength becomes extremely poor, and if the pitch P is made smaller, the pulling strength is improved. To bring a new state. According to this experiment 3, P / M is in the range of 0.33 to 0.58, and therefore,
It was found that good condition was 0.33 ≦ P / M ≦ 0.58.

[Table 4]

According to the experimental result 3 shown in Table 3 above, the value of P / M is good if 0.31 ≦ P / M ≦ 0.56, but the experimental result shown in Table 4 above. According to 4.
It is good if 0.33 ≦ P / M0.58. Therefore, from the results of these two experiments, the lower limit value of P / M is 0.31, the upper limit value is 0.58, and 0.31 ≦ P
If /M≦0.58, it is presumed that both the screwability with respect to the cement plate and the pull-out strength can be satisfied.

[0030]

According to the present invention as set forth in claim 1, unlike the prior art, it is not necessary to pre-drill a prepared hole in the cement plate 1, and the screw 6 constituting a self-drilling screw is used for drilling and tapping fastening. Therefore, the work is easy and the working time can be shortened.

When the conventional self-drilling screw for a metal plate is diverted to the anchor plate mounting structure for the cement plate, the screw thread 11 of the shank 8 enters the hole before the drill 9 penetrates the adhered wall 5. According to the present invention, the length L1 of the drill 9 in the screw 6 and the length L2 of the shank 8 and the wall thickness of the adhered wall 5 in the cement plate 1 are reduced. T and depth D of hollow part 4
Of T ≦ L1, T ≦ L2, and L1 + L
Since 2 ≦ T + D, the drill 9 can penetrate into the adhered wall 5 and complete the perforation, and then the screw thread 11 can be inserted into the perforated hole to start tapping. Promise a good approach.

Moreover, when the conventional self-drilling screw for a metal plate is diverted to the anchor plate mounting structure for the cement plate, a screw stupid state is brought about with a low torque, whereas according to the present invention, the screw is used. Since the relationship between the blade diameter K of the drill 9, the crest diameter M of the screw thread 11, and the root diameter R of the screw thread 11 in 6 is set to R ≦ K and M / K ≦ 1.25,
While maintaining good screwability, the screw back torque can be greatly improved and a strong tightening force can be obtained.

Further, according to the present invention, the relation between the thread diameter M of the thread 11 in the screw 6 and the pitch P is 0.31≤P / M.
Since it is configured to be ≦ 0.58, there is an effect that the screwability can be improved while ensuring the drawing strength.

According to the present invention described in claim 2, there is an advantage that the screw 6 that achieves the above-mentioned effects can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an anchor plate mounting structure of the present invention in plan view.

FIG. 2 is an enlarged front view showing one embodiment of the mounting screw of the present invention.

3A and 3B show the operation of the mounting screw, FIG. 3A is a sectional view showing a state where a drill is inserted into a wall to be attached, and FIG. 3B is a sectional view showing a state in which screw fastening is completed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extrusion-molded cement board 2 Anchor board 3 Adhering part 4 Hollow part 5 Adhering wall 6 Screw 7 Head 8 Shank 9 Drill 11 Screw thread 13 Blade T Adhering wall thickness D Hollow part depth L1 Drill length L2 Shank length K Blade diameter M Peak diameter R Valley diameter P Pitch

Claims (2)

[Claims] 1. An attachment structure of an anchor plate to an extrusion-molded cement plate, wherein the cement plate has a hollow structure having a depth D by forming an adhered part in a hollow structure, and a wall thickness facing the hollow part. A self-attached screw having a thread at a tip of a threaded shank extending from a head, the screw being screwed to the adhered wall through a hole of an anchor plate. Configure the drill screw, drill length L
1 and shank length L2 with respect to the wall thickness T of the adhered wall and the depth D of the hollow portion constituting the adhered portion, T ≦ L1,
In addition, T ≦ L2 and L1 + L2 ≦ T + D, and the screw has a blade diameter K of the drill, a thread diameter M of the thread, a root diameter R of the thread, and a pitch P of the thread. R ≦ K and M / K
An anchor plate mounting structure characterized in that ≦ 1.25 and 0.31 ≦ P / M ≦ 0.58. 2. A screw for attaching an anchor plate to an extruded cement plate, the screw constituting a self-drilling screw having a drill at the tip of a shank with a thread extending from the head, The length L1 and the length L2 of the shank are configured such that T ≦ L1 and T ≦ L2 with respect to the wall thickness T of the adhered wall of the cement plate, and the screw is a drill blade diameter. K, the thread crest diameter M, the thread trough diameter R, and the thread pitch P are R ≦ K and M / K
A mounting screw in an anchor plate mounting structure, characterized in that ≦ 1.25 and 0.31 ≦ P / M ≦ 0.58.