JP7783586B2 - fixed structure - Google Patents

Description

The present invention relates to a structure for fixing a metal plate using screws .

Screws for steel plates, such as those described in Patent Document 1, are known as screws for fastening thin steel plates (metal plates). These screws for steel plates have a screw head, a parallel thread portion that extends from the screw head and has an outer peripheral surface on which a thread portion is formed, and a hole for inserting a tool. Because the hole extends from the head to the shank of a steel plate screw, it is possible to make the head thin and prevent the head from protruding too much from the metal plate when fastened.

The screw head also has an annular protrusion formed on the outer edge of the bottom surface of the screw head, and a recess formed on the inner periphery of the protrusion.

When a steel plate screw is tightened while the steel plate is in contact with the convex portion, the thrust of the parallel thread portion causes the periphery of the screw hole in the steel plate (the part inside the convex portion) to curl up (bow up), enter into the concave portion and adhere tightly. As a result, the rotational resistance of the steel plate screw increases suddenly, causing the steel plate screw to stop rotating and preventing free rotation.

Japanese Patent Application Laid-Open No. 2002-122113

However, when the steel plate screw described in Patent Document 1 is used to fasten a thin steel plate, the peripheral edge of the screw hole formed in the thin steel plate by the steel plate screw warps up, and this warping causes the diameter of the screw hole to increase. As a result, the inner diameter of the screw hole becomes larger than the outer diameter of the steel plate screw, which may make it difficult to effectively prevent the steel plate screw from spinning freely relative to the thin steel plate when fastening the steel plate screw.

The present invention has been made in view of the above-mentioned problems, and has an object to provide a fixing structure using screws that can effectively suppress free rotation.

In order to solve the above problem, a fixing structure of the present invention comprises a screw and two metal plates connected to each other by being penetrated by the screw in a thickness direction, the screw comprising a head, a shank extending to one side from the head and having an outer circumferential surface on which a thread portion is formed, and a hole formed over a range from an end face on the other side of the head to the inside of the shank, into which a tip of a tool for rotating the screw around the axis of the shank can be inserted from the other side, the head having a reference surface facing one side and extending radially outward of the shank, and a plurality of protrusions protruding from the reference surface to one side and formed side by side in the rotation direction of the shank, the plurality of protrusions extending from the shank to the radially outward of the shank, each having 18 to 24 protrusions arranged at equal intervals in the rotational direction, and each of the plurality of protrusions has a first surface formed facing the tightening direction in the rotational direction, and a second surface inclined toward the opposite direction to the tightening direction in the rotational direction, and the rise angle of the first surface with respect to the reference plane is greater than the rise angle of the second surface with respect to the reference plane, the shank has a tapered portion adjacent to the head and having a diameter that decreases as it extends from the reference plane to one side, and the tapered portion has a flat portion with a flat outer peripheral surface between the head and the other end of the threaded portion, and the shank is engaged with the metal plate with the plurality of protrusions in close contact with the metal plate .

The screw used in this fixing structure has a hole extending from the other end face of the head to the inside of the shank, so the thickness of the head can be made relatively small compared to the predetermined hole depth for inserting a tool, which prevents the head from protruding too much from the metal plate when the screw is fastened to the metal plate.

The head also has multiple protrusions that protrude from the reference surface to one side and are aligned in the direction of rotation of the shank. When this screw is fastened to a metal plate, for example, the multiple protrusions engage with the surface of the metal plate, increasing the frictional force between the head and the metal plate. This effectively prevents the screw from spinning freely.

Furthermore, because the multiple protrusions extend radially outward from the shank, the peripheral edge of the screw hole, which tends to warp due to the force from the threaded portion, comes into contact with the multiple protrusions, thereby suppressing the warping of the peripheral edge of the screw hole. This prevents the screw hole from widening due to the peripheral edge warping, and the increased frictional resistance increases torque, preventing the screw from spinning freely.

Furthermore, for each of the multiple protrusions, the rise angle of the first surface facing the tightening direction relative to the reference surface is greater than the rise angle of the second surface facing the opposite direction to the tightening direction relative to the reference surface. Therefore, when tightening the screw into a metal plate, the first surface bites into the surface of the metal plate, increasing the tightening torque and preventing the screw from spinning freely. Furthermore, when loosening the screw, the sliding resistance of the second surface against the surface of the metal plate is relatively smaller than the sliding resistance against the first surface, allowing the screw to rotate smoothly.

In addition, the multiple protrusions are arranged at equal intervals in the rotational direction. This allows the torque generated between the head and the metal plate when the screw is tightened into the metal plate to be approximately uniform around the entire circumference of the head.

Furthermore, the plurality of protrusions are formed in a number of 18 or more but less than 24, arranged in the direction of rotation. By appropriately setting the number of protrusions arranged in the direction of rotation in this way, the tightening torque of the screw against the metal plate can be effectively increased, and therefore, freewheeling of the screw when tightening the screw against the metal plate can be effectively suppressed.

The shank also has a tapered section adjacent to the head, with a diameter that decreases from the reference plane toward one side. This allows the outer diameter of the shank on one side of the tapered section to be smaller than the outer diameter of the end on the other side of the tapered section, while still providing an area in the tapered section of the shank for forming a hole with a predetermined depth. As a result, when the screw is initially fastened to a metal plate, the outer diameter of the shank on one side of the tapered section is relatively small, thereby reducing the contact area between the screw and the metal plate. This reduces the frictional resistance between the screw and the metal plate, suppressing an increase in torque while also preventing the head from protruding too far from the metal plate.

Furthermore, since the shaft engages with the metal plate with the multiple protrusions in close contact with the metal plate, a fixed structure can be provided in which the metal plates are firmly fixed together by interlocking the multiple protrusions with the metal plate, which is prevented from warping by the multiple protrusions.

In the screw, it is preferable that the rising angle of the first surface relative to the reference surface is 90 degrees.

With this configuration, the first surface and the rotation direction of the screw are perpendicular to each other, so when the screw is tightened against the metal plate, the metal plate caught between the multiple protrusions is received from the front by the first surface, more effectively preventing the screw from spinning freely.

As described above, the fixing structure using a screw of the present invention can effectively prevent the peripheral edge of the screw hole from warping upward.

FIG. 2 is a vertical cross-sectional view showing a fixing structure according to an embodiment of the present invention. FIG. 4 is a side view of a screw of the fixing structure. FIG. 4 is a top view showing the head of the screw. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. FIG. 4 is a side view showing a protruding portion of the screw. This is an exploded oblique view showing the state in which the joist and ceiling runner are connected using the screws. A cross-sectional view showing the state in which two partition studs are connected together using the screw. FIG. 10 is an exploded perspective view showing the state in which the partition runner and the stud are connected using the screw. FIG. 10 is an exploded perspective view showing the state in which a metal plate is fixed to a partition stud using the screw. This is an exploded perspective view showing the state in which the metal plate is fixed to the joist using the screws.

Embodiments of the present invention will now be described with reference to the accompanying drawings. Please note that the following embodiments are examples of specific embodiments of the present invention and are not intended to limit the technical scope of the present invention.

As shown in FIG. 1, the fixing structure 1 according to an embodiment of the present invention comprises a screw 10 and two metal plates 50, 50 that are connected to each other by being penetrated in the thickness direction by the screw 10.

The screw 10 is a component for fastening two metal plates 50, 50 together by penetrating them. Specifically, as shown in Figure 2, the screw 10 comprises a head 20 that is disk-shaped in plan view, a shank 30 that extends from the head 20 to one side (the lower side of the paper in Figure 2) and has an outer circumferential surface on which a threaded portion 32 is formed, and a hole 40 (see Figure 3) into which the tip of a tool can be inserted from the other side to rotate the screw 10 around the axis of the shank 30. The hole 40 is formed over a range from the end face on the other side (the upper side of the paper in Figure 2) of the head 20 to the interior of the shank 30.

The shank 30 has a threaded portion 32 formed so that the screw 10 can be tightened against the metal plate 50 by rotating the screw 10 clockwise, and can be loosened against the metal plate 50 by rotating the screw 10 counterclockwise. Hereinafter, the clockwise direction of rotation of the screw 10 will be referred to as tightening direction A, and the counterclockwise direction will be referred to as loosening direction B. Note that the screw 10 may have a threaded portion 32 in which the tightening direction A and loosening direction B are opposite to those described above.

The head 20 is configured to prevent the screw 10 from spinning freely relative to the metal plate 50 when the screw 10 is rotated in the tightening direction A while the screw 10 is fastened to the metal plate 50. Specifically, as shown in Figures 4 and 5, the head 20 has a reference surface 22 that faces one side and extends radially outward from the shank 30, and multiple protrusions 24 that protrude from the reference surface 22 to one side and are aligned in the rotational direction of the shank 30.

In this embodiment, the thickness of the head 20 is set in the range of 0.55 mm to 0.70 mm to prevent the head 20 from protruding too much from the metal plate 50 when the screw 10 is fastened to the metal plate 50.

The multiple protrusions 24 are parts that prevent the screw 10 from spinning freely by generating torque between the screw 10 and the metal plate 50 when the screw 10 is tightened against the metal plate 50. These multiple protrusions 24 are arranged at equal intervals in the rotational direction so that the resistance generated between the head 20 and the metal plate 50 when the screw 10 is tightened against the metal plate 50 is approximately uniform around the entire circumference of the head 20.

Table 1 shows the results and average values of the maximum loads (kgf) α to γ generated between each screw and the metal plate 50 when screws with 0, 18, and 24 protrusions 24 are tightened into the metal plate 50, measured three times each. Specifically, α to γ represent the maximum loads generated when the head 20 is in contact with the metal plate 50. Note that α is the maximum load generated between the metal plate 50 and a screw with 0 protrusions 24, β is the maximum load generated between the metal plate 50 and a screw with 18 protrusions 24, and γ is the maximum load generated between the metal plate 50 and a screw with 24 protrusions 24. The numbers in parentheses represent the number of protrusions 24 in each case.

As shown in Table 1 above, the inventors have confirmed that the maximum tightening torque of the screw 10 (the maximum of the average values in Table 1) exists within the range of 1 to 24 protrusions aligned in a row in the rotational direction. Furthermore, the inventors have confirmed that the average maximum value of the load generated between the screw 10 and the metal plate 50 is greater and the tightening torque increases when there are 18 protrusions aligned in a row in the rotational direction compared to when there are 24 protrusions.

For this reason, it is preferable that the multiple protrusions 24 be formed in a number of fewer than 24, aligned in a line in the rotational direction, and more preferably, 18 protrusions 24 aligned in a line in the rotational direction, as shown in Figure 4. Furthermore, it is preferable that the height of the multiple protrusions 24 be set in the range of 14.3% to 36.4% of the thickness of the head 20.

As shown in Figure 4, the multiple protrusions 24 extend radially outward from the shaft portion 30. As shown in Figure 5, the multiple protrusions 24 each have a first surface 24a facing the tightening direction A of the rotational direction, and a second surface 24b facing the opposite direction to the tightening direction (loosening direction B) of the rotational direction. The second surface 24b slopes toward the reference surface 22 as it moves from the first surface 24a toward the loosening direction B.

The multiple protrusions 24 have a shape that is set so that the resistance between the first surface 24a and the metal plate 50 when the screw 10 is rotated in the tightening direction A is greater than the resistance between the second surface 24b and the metal plate 50 when the screw 10 is rotated in the loosening direction B. Specifically, the rise angle of the first surface 24a with respect to the reference surface 22 is greater than the rise angle of the second surface 24b with respect to the reference surface 22, as shown in FIG. 5. In this embodiment, the rise angle of the first surface 24a with respect to the reference surface 22 is set to 90 degrees, and the rise angle of the second surface 24b with respect to the reference surface 22 is set to less than 90 degrees.

In addition, in this embodiment, multiple protrusions 24 are arranged adjacent to each other in the rotational direction. Specifically, the other edge of the second surface 24b (the edge on the loosening direction side) is connected to the edge of the first surface 24a of another adjacent protrusion 24 on the tightening direction A side.

In addition, to ensure that the multiple protrusions 24 efficiently engage with the metal plate 50, the angle between the first surface 24a and the second surface 24b is an acute angle, as shown in Figure 5. In this embodiment, the height (length in the axial direction) of the multiple protrusions 24 is set within the range of 0.10 mm to 0.20 mm.

The shank 30 has a tapered section 34 adjacent to the head 20 and having a diameter that decreases from the reference plane 22 toward one side; a body 35 connected to the tapered section 34 and having a constant diameter along the axial direction; a tip 36 connected to the body 35 and having a diameter that decreases toward one side; and a threaded section 32 provided on the outer periphery of the tapered section 34, body 35, and tip 36. The shank 30 engages with the metal plate 50 with the multiple protrusions 24 in close contact with the metal plate 50.

In this embodiment, the hole 40 is formed in a cross shape as shown in Figure 3. The hole 40 is formed over the range from the other end face of the head 20 to the inside of the tapered portion 34 of the shaft 30.

The depth of the hole 40 is predetermined by standards, so if the hole 40 is formed only in the head 20, it is necessary to ensure the thickness of the head 20. In this embodiment, the hole 40 is formed over the range from the other end face of the head 20 to the inside of the tapered portion 34 of the shank 30, allowing the thickness of the head 20 to be relatively small.

As shown in Figure 2, the tapered portion 34 has a flat portion 38 that prevents warping around the edges of the screw holes in the two metal plates 50, 50. The flat portion 38 is formed at the other end of the tapered portion 34, and its radially outer peripheral surface is flat. In other words, the threaded portion 32 is provided in an area on one side of the flat portion 38 on the shaft portion 30.

The axial length of the flat portion 38 is set to be approximately the same as the combined thickness of the two metal plates 50, 50, specifically, approximately 1.0 mm. Furthermore, in this embodiment, a thin steel plate with a thickness of approximately 0.4 mm to 0.5 mm is used as the metal plate 50. As a result, the metal plates 50, 50 are positioned in the gap between the head 20 of the screw 10 and the other end of the threaded portion 32.

Below, we will explain an example in which this fixing structure 1 is applied.

(1) Example 1
As shown in Figure 6, the fixing structure of Example 1 includes a ceiling runner 102 extending in a predetermined direction, a tubular joist 104 extending in a direction perpendicular to the predetermined direction and connected to the ceiling runner 102, and screws 10 that fix the ceiling runner 102 and the joist 104.

The ceiling runner 102 has a mounting plate portion on which the end of the joist 104 rests. The mounting plate portion of the ceiling runner 102 and the side walls of the joist 104 that rest on the mounting surface of the mounting plate portion correspond to the metal plates 50, 50, respectively. By tightening the screws 10 into the mounting plate portion of the ceiling runner 102 and the side walls of the joist 104, the side walls of the joist 104 are fixed to the mounting plate portion of the ceiling runner 102.

(2) Example 2
As shown in FIG. 7 , the fixing structure of Example 2 has two first studs 202, 202 arranged side by side in a predetermined direction, a second stud 204 connecting these two first studs 202, 202, and a screw 10 fixing these first studs 202, 202 and the second stud 204 together.

The first studs 202, 202 and the second studs 204 are each formed from C-section steel. Specifically, the first studs 202, 202 and the second studs 204 each have a web, a pair of flanges rising from both ends of the web, and a lip rising from the edge of the flange opposite the edge to which the web is connected.

In this embodiment, the web of the second stud 204 is positioned so as to straddle the flanges of the two first studs 202, 202. The flanges of the first studs 202, 202 and the web of the second stud 204 correspond to the metal plates 50, 50, respectively. By tightening the screws 10 into the webs of the first studs 202, 202 and the second stud 204, the web of the second stud 204 is fixed to the flanges of the first studs 202, 202.

(3) Example 3
As shown in Figure 8, the fixing structure of Example 3 comprises a partition runner 304 extending in a predetermined direction and having a groove that opens upward perpendicular to the predetermined direction, a tubular partition stud 302 that is square in cross section and extends in the vertical direction, with its lower end inserted into the groove of the partition runner 304, and a screw 10 that fixes the partition runner 304 and the partition stud 302.

The partition runner 304 has a mounting portion on which the partition stud 302 is placed, and a pair of clamping portions that rise from both widthwise ends of the mounting portion and clamp the partition stud 302.

The side of the stud 302 and the clamping portion of the partition runner 304 correspond to the metal plates 50, 50, respectively. By tightening the screws 10 into the side of the stud 302 and the clamping portion of the partition runner 304, the clamping portion of the partition runner 304 is fixed to the side of the stud 302.

(4) Example 4
9, the fixing structure of Example 4 comprises a plurality of first studs 202 arranged in a row, a partition wall supported by the first studs 202, 202 between two adjacent first studs 202, 202, connecting members 404 connecting the first studs 202 to the partition wall, and screws 10 fixing the first studs 202 to the connecting members 404. The first studs 202 used in this example are the same as the first studs 202 used in Example 2.

The connecting member 404 has a plate-shaped portion that is fixed in close contact with the flange of the first stud 202. The flange of the first stud 202 and the plate-shaped portion of the connecting member 404 correspond to the metal plates 50, 50, respectively. By tightening the screws 10 into the flange of the first stud 202 and the plate-shaped portion of the connecting member 404, the connecting member 404 is fixed to the flange of the first stud 202.

(5) Example 5
10, the fixing structure of Example 5 includes two adjacent sills 104, 104, a connecting member 504 connecting these two sills 104, 104, and a screw 10 for fixing the sills 104, 104 and the connecting member 504. The sills 104 of this example are the same as those of Example 1.

The connecting member 504 has a plate-shaped portion that is fixed in close contact with the two soffits 104, 104. The soffits 104 and the plate-shaped portion of the connecting member 504 correspond to the metal plates 50, 50, respectively. The connecting member 504 is fixed to the soffits 104 by tightening screws 10 into the plate-shaped portions of the soffits 104 and the connecting member 504.

(Action and effect)
With the screw 10 of this embodiment, the hole 40 is formed over a range from the other end face of the head 20 to the inside of the shank 30, so the thickness of the head 20 can be made relatively small compared to the depth of the hole 40, which is predetermined as a dimension that allows a tool to be inserted. This makes it possible to prevent the head 20 from protruding too much from the metal plate 50 when the screw 10 is fastened to the metal plate 50.

In addition, the head 20 has multiple protrusions 24 that protrude from the reference plane to one side and are aligned in the rotational direction of the shank 30. When the screw 10 is fastened to a metal plate 50, the multiple protrusions 24 engage with the surface of the metal plate 50, increasing the frictional force between the head 20 and the metal plate 50. This effectively prevents the screw 10 from spinning freely.

Furthermore, because the multiple protrusions 24 extend radially outward from the shank 30, the peripheral edge of the screw hole, which tends to warp due to the force from the threaded portion, comes into contact with the multiple protrusions 24, thereby preventing the peripheral edge of the screw hole from warping upward. This increases the area where the multiple protrusions 24 interlock with the surface of the metal plate 50, and the increased frictional resistance increases torque, preventing the screw 10 from spinning freely.

The rise angle of the first surface 24a relative to the reference surface 22 is greater than the rise angle of the second surface 24b relative to the reference surface 22. Therefore, when the screw 10 is tightened into the metal plate 50, the first surface 24a bites into the surface of the metal plate 50, increasing the tightening torque and preventing the screw 10 from spinning freely. When the screw 10 is loosened, the sliding resistance of the second surface 24b relative to the surface of the metal plate 50 is relatively smaller than the sliding resistance of the first surface 24a, allowing the screw 10 to rotate smoothly.

In addition, the rising angle of the first surface 24a relative to the reference surface 22 is 90 degrees, and the first surface 24a and the rotation direction of the screw 10 are perpendicular to each other. Therefore, when the screw 10 is tightened against the metal plate 50, the metal plate 50 that is caught between the multiple protrusions 24 is received from the front by the first surface 24a, more effectively preventing the screw 10 from spinning freely.

In addition, because the multiple protrusions 24 are formed in a line at equal intervals in the rotational direction, the torque generated between the head 20 and the metal plate 50 when the screw 10 is tightened into the metal plate 50 can be made approximately uniform around the entire circumference of the head 20.

Furthermore, the protrusions 24 are formed as 18 protrusions 24 arranged in a row in the rotational direction. By appropriately setting the number of protrusions 24 arranged in a row in the rotational direction, the tightening torque of the screw 10 against the metal plate 50 can be effectively increased. This effectively prevents the screw 10 from spinning freely when tightening the screw 10 against the metal plate 50.

The shank 30 also has a tapered section 34 adjacent to the head 20, with a diameter that decreases from the reference plane 22 toward one side. This allows the tapered section of the shank 30 to have an area for forming a hole 40 with a predetermined depth, while making the outer diameter of the shank 30 on one side of the tapered section 34 smaller than the outer diameter of the end on the other side of the tapered section 34. As a result, when the screw 10 is initially fastened to the metal plate 50, the outer diameter of the portion of the shank 30 on one side of the tapered section 34 (tip 36) is relatively small, thereby reducing the contact area between the screw 10 and the metal plate 50. Therefore, by reducing the frictional resistance between the screw 10 and the metal plate 50, it is possible to prevent the head 20 from protruding from the metal plate 50 from becoming too large while suppressing an increase in torque.

In addition, the shaft portion 30 engages with the metal plate 50 with the multiple protrusions 24 in close contact with the metal plate 50. By engaging the multiple protrusions 24 with the metal plate 50, which is prevented from warping by the multiple protrusions 24, a fixing structure 1 can be provided in which the metal plates 50, 50 are firmly fixed together.

(Modification)
The above-described embodiments are merely examples of preferred specific examples of the present invention, and the present invention is not limited to the above-described embodiments.

In the above embodiment, the hole 40 was formed in a cross shape, but the shape of the hole 40 is not limited to a cross shape and may be formed in a shape such as a minus sign.

In the above embodiment, a thin steel plate was used as the metal plate 50, but the plate that can be used as the metal plate 50 is not limited to a thin steel plate, and a plate made of other metals, such as an aluminum plate, may also be used.

In the above embodiment, the rise angle of the first surface 24a relative to the reference surface 22 is set to 90 degrees. However, the rise angle of the first surface 24a relative to the reference surface 22 does not have to be set to 90 degrees.

In the above embodiment, the multiple protrusions 24 were formed in a row in the rotational direction, but the positions at which the multiple protrusions 24 are formed are not limited to this; for example, they may be formed in positions spaced apart from each other in the radial direction of the shaft portion 30.

In the above embodiment, the axial length of the flat portion 38 is approximately equal to the total thickness of the two metal plates 50, 50, but it does not necessarily have to be approximately equal to the total thickness. For example, the axial length of the flat portion 38 may be smaller than the total thickness of the two metal plates 50, 50. This allows the force exerted by the threaded portion 32 to be used as a force for engaging the multiple protrusions 24. As a result, the metal plates 50, 50 are pushed upward by the threaded portion 32, strengthening the anti-rotation function.

It goes without saying that various other design modifications are possible within the scope of the claims of this invention.

REFERENCE SIGNS LIST 1 Fixing structure 10 Screw 20 Head 22 Reference surface 24 Protruding portion 24a First surface 24b Second surface 30 Shank 32 Threaded portion 34 Tapered portion 35 Body 36 Tip 38 Flat portion 40 Hole 50 Metal plate A Fastening direction B Loosening direction

Claims (2)

With a bis
two metal plates connected to each other by being penetrated in the thickness direction by the screws;
The screw is
The head and
a shaft portion extending from the head portion to one side and having an outer circumferential surface on which a thread portion is formed;
a hole formed over a range from the end surface on the other side of the head to the inside of the shank, into which a tip of a tool for rotating the screw around the axis of the shank can be inserted from the other side;
The head portion has a reference surface facing one side and extending radially outward of the shaft portion, and a plurality of protrusions protruding from the reference surface to one side and formed side by side in a rotational direction of the shaft portion,
As the plurality of protrusions, 18 or more but less than 24 protrusions are formed which extend from the shaft portion radially outward of the shaft portion and are arranged at equal intervals in the rotational direction,
The plurality of protrusions have a first surface formed facing a tightening direction in the rotation direction, and a second surface inclined facing a direction opposite to the tightening direction in the rotation direction,
a rising angle of the first surface with respect to the reference surface is larger than a rising angle of the second surface with respect to the reference surface;
the shaft portion has a tapered portion adjacent to the head portion and having a diameter that decreases toward one side from the reference plane;
the tapered portion has a flat portion with a flat outer circumferential surface between the head and the other end of the threaded portion,
A fixed structure in which the shaft portion is engaged with the metal plate with the multiple protrusions in close contact with the metal plate . The fixing structure according to claim 1,
A fixed structure , wherein the first surface has a rising angle of 90 degrees relative to the reference surface.