JP2021099110A - Screw - Google Patents

Abstract

To provide a screw that can maintain a fixing strength even for a thin plate.SOLUTION: A screw 10 includes: a male screw part 14 with a helical projection 16; and a tapered part 18 located on a tip side from the male screw part 14. The helical projection 16 is not provided in the tapered part 18. A diameter R1 of the male screw part 14 at a surface orthogonal to a rotational axis A of the screw 10 is equal to or more than a pitch P1 of the helical projection 16 in a direction along the rotational axis A.SELECTED DRAWING: Figure 1

Description

The present invention relates to, for example, screws for thin metal plates.

Screws may be used to fasten separate members from each other. Appropriate types and shapes of screws are selected according to the application. For example, when an article such as a solar cell module is installed on the roof of a building such as a house or a factory, a fixture for fixing the article to the roof material is fastened to the roof material by, for example, a screw (Patent Document). FIG. 3 (b) of FIG.

Japanese Unexamined Patent Publication No. 2015-227576

The inventor of the present application has considered installing an article such as a solar cell module on the roof of a factory or the like. When the roofing material is composed of a thin plate such as a metal plate, the fixture for fixing the article needs to be fixed to the thin plate.

When the inventor of the present application uses a general screw, for example, a screw for fixing such a fixture to a thin plate, the fixing strength is insufficient or the possibility of installation failure due to the screw idling increases. I found out to do.

Therefore, a screw that can maintain the fixing strength even for a thin plate is desired.

The screw according to one embodiment has a male screw portion having a spiral protrusion and a tapered portion on the tip side of the male screw portion. The spiral protrusion is not provided on the tapered portion, and the diameter of the male screw portion on the plane orthogonal to the rotation axis of the screw is the pitch of the spiral protrusion in the direction along the rotation axis. That is all.

According to the above aspect, the fixing strength can be maintained even for a thin plate.

It is a side view which shows the screw which concerns on one Embodiment. It is a side view which shows the state of inserting the screw which concerns on one Embodiment into a thin plate. It is a side view which shows the state in which the screw which concerns on one Embodiment is completely inserted into a thin plate. It is a side view which shows the screw which concerns on a reference example. It is a side view which shows the state of inserting the screw which concerns on a reference example into a thin plate. It is a side view which shows the state that the screw which concerns on a reference example was completely inserted into a thin plate.

Hereinafter, embodiments will be described with reference to the drawings. In the drawings below, the same or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic and the ratio of each dimension may differ from the actual one.

FIG. 1 is a side view showing a screw according to an embodiment. FIG. 2 is a side view showing how the screw according to the embodiment is inserted into the thin plate. FIG. 3 is a side view showing a state in which the screw according to the embodiment is completely inserted into the thin plate.

The screw 10 according to the present embodiment is suitably used for fastening the member to be fastened 200 to a thin plate, particularly a thin plate made of metal 100. In the examples shown in FIGS. 2 to 3, a state in which the member to be fastened 200 is fastened to the thin plate 100 by the screw 10 is shown.

The screw 10 according to the present embodiment has a head portion 12, a male screw portion 14 having a spiral protrusion 16, and a tapered portion 18 on the tip side of the male screw portion 14. The head 12, the male screw portion 14, and the tapered portion 18 may be integrally and inseparably composed of a metal such as iron, stainless steel, or an alloy steel material.

The shape of the head 12 is not particularly limited as long as it can be screwed by a tool. For example, the head 12 may have the shape of a substantially hexagonal column. The head 12 may have a size capable of pressing around the through hole 210 of the member to be fastened 200 in a state where the member to be fastened 200 is fastened to the thin plate 100. The maximum diameter of the head portion 12 seen from the direction of the rotation axis A of the screw 10 may be, for example, about 5 to 30 mm.

The male screw portion 14 is located between the head portion 12 and the tapered portion 18. The male screw portion 14 includes a spiral protrusion 16 formed on the outer periphery thereof. One spiral protrusion 16 may be formed on the male screw portion 14. The spiral protrusion 16 is not formed in the tapered portion 18, which will be described later.

The diameter R1 of the male screw portion on the plane orthogonal to the rotation axis A of the screw 10 is equal to or greater than the pitch P1 of the spiral protrusion 16 in the direction along the rotation axis A. The pitch P1 corresponds to the distance between the protrusions 16 adjacent to each other in the direction along the rotation axis A.

The diameter R1 of the male screw portion may be, for example, 4 mm or more, preferably 6 mm or more. The diameter R1 of the male screw portion may be, for example, 25 mm or less, preferably 20 mm or less.

The pitch P1 may be, for example, 0.1 mm or more, preferably 0.3 mm or more. Further, the pitch P1 may be, for example, 4.0 mm or less, preferably 3.5 mm or less.

As will be described later, the pitch P1 of the spiral protrusions 16 may be larger than the thickness of the thin plate 100 to which the screws 10 are fastened. As an example, the screw 10 according to the present embodiment is also suitably used for a thin plate 100 having a thickness of, for example, 3 mm or less, more specifically 2 mm or less, and further limitedly 1 mm or less.

The spiral protrusion 16 is preferably formed up to the vicinity of the head 12. As a result, even if the thickness of the member to be fastened 200 is small, the member to be fastened 200 can be fastened to the thin plate 100. The distance L2 between the spiral protrusion 16 and the head 12 may be equal to or less than the pitch P1 of the spiral protrusion 16. The distance L2 between the spiral protrusion 16 and the head 12 may be, for example, 10 mm or less, preferably 6.0 mm or less, and more preferably 4.5 mm or less.

The distance L1 between the tapered portion 18 and the spiral protrusion 16 may be, for example, 15 mm or less, preferably 10 mm or less, and more preferably 6 mm or less. As a result, after the tapered portion 18 makes a hole in the thin plate 100 as described later, the male screw portion 14 can be promptly started to be screwed into the thin plate 100.

The tapered portion 18 is defined by a portion that tapers toward the tip of the screw 10, that is, the end opposite to the head portion 12. For example, the tapered portion 18 may have a conical shape, a pyramid shape, a truncated cone shape, a truncated pyramid shape, or the like.

Preferably, the leading edge of the tapered portion 18 may have a substantially sharp shape. In this case, the tapered portion 18 may have, for example, a conical shape or a pyramid shape. This makes it easier to screw the screw 10 into the thin plate 100. In particular, even if the thin plate 100 is a hard plate such as a metal plate, the screw 10 can be easily screwed into the thin plate 100.

The tapered portion 18 is preferably inclined at an angle of, for example, 50 degrees or less, preferably 45 degrees or less, and more preferably 40 degrees or less in the cross section of the screw along the plane passing through the rotation axis A. As a result, even if the thin plate 100 is a hard plate such as a metal plate, the screw 10 can be easily twisted by the thin plate 100. Further, the tapered portion 18 may be inclined at an angle of, for example, 10 degrees or more in the cross section of the screw along the plane passing through the rotation axis A.

Further, the tapered portion 18 preferably has a shape that is rotationally symmetric with respect to the rotation axis A. Examples of such a rotationally symmetric shape include a conical shape and a truncated conical shape. As described above, considering the ease of twisting into the thin plate 100, it is more preferable that the tapered portion 18 has a substantially conical shape. In this case, when the tapered portion 18 of the screw 10 is screwed into the thin plate 100, the force in the rotational direction due to the twist of the tapered portion 18 is unlikely to be applied to the thin plate 100, so that burrs are less likely to occur in the thin plate 100 as described later. There are merits.

The maximum radius R2 of the tapered portion 18 on the plane orthogonal to the rotation axis A of the screw 10 is preferably 1/4 or more of the diameter R1 of the male screw portion and less than 1/2 of the diameter R1 of the male screw portion. Specifically, the maximum radius R2 of the tapered portion 18 may be 1.25 mm or more, preferably 2.0 mm or more. The maximum radius R2 of the tapered portion 18 may be 15 mm or less, preferably 12 mm or less.

Next, a state in which the member to be fastened 200 is fastened to the thin plate 100 by using the screw 10 according to the present embodiment will be described. First, the member to be fastened 200 is placed on the thin plate 100. Then, the tapered portion 18 of the screw 10 is screwed into the thin plate 100 through the through hole 210 of the member to be fastened 200 (FIG. 2).

At this time, the tapered portion 18 of the screw 10 penetrates the thin plate 100. Since the tapered portion 18 does not have the spiral protrusion 16, the thin plate 100 is bent downward (on the tip side of the screw) around the penetrating portion (see also FIG. 2).

Next, as the screw tightening is promoted, the spiral protrusion 16 begins to engage with the downwardly bent portion 102 of the thin plate 100. When the screw 10 is completely fastened to the thin plate 100, the spiral protrusion 16 is engaged with the downwardly bent portion 102 of the thin plate 100. Further, the member to be fastened 200 is sandwiched between the spiral head 12 and the thin plate 100.

As described above, the diameter R1 of the male screw portion is equal to or greater than the pitch P1 of the spiral protrusion 16. As a result, the length of the downwardly bent portion 102 of the thin plate 100 in the direction along the rotation axis A becomes "(pitch P1 of the spiral protrusion 16) / 2" or more. Therefore, at least one protrusion 16, preferably two protrusions 16, is engaged with the downwardly bent portion 102 of the thin plate 100 in the direction along the rotation axis A. Therefore, the spiral protrusion 16 is firmly engaged with the thin plate 100, and the fixing strength between the member to be fastened 200 and the thin plate 100 can be maintained.

Further, even when the pitch P1 of the spiral protrusion 16 is larger than the thickness of the thin plate 100, the spiral protrusion 16 engages with the portion 102 bent downward of the thin plate 100, so that the screw slips. It is unlikely to occur, and the member to be fastened 200 and the thin plate 100 can be firmly fastened.

Further, from the viewpoint of maintaining the shape of the downwardly bent portion 102 of the thin plate 100, as described above, the tapered portion 18 preferably has a rotationally symmetric shape with respect to the rotation axis A.

Next, the screw according to the reference example will be described with reference to FIGS. 4 to 6. FIG. 4 is a side view showing a screw according to a reference example. FIG. 5 is a side view showing how the screw according to the reference example is inserted into the thin plate. FIG. 6 is a side view showing a state in which the screw according to the reference example is completely inserted into the thin plate.

The screw 50 according to the reference example has a head portion 52, a male screw portion 54 having a spiral protrusion 56, and a tapered portion 58 on the tip side of the male screw portion 14. In the reference example, the spiral protrusion 56 reaches the tapered portion 58 (FIG. 4). The screw 50 according to the reference example has the same configuration as that of the above embodiment except that the spiral protrusion 56 reaches the tapered portion 58.

Next, a state in which the member to be fastened 200 is fastened to the thin plate 100 using the reference screw 10 will be described. First, the member to be fastened 200 is placed on the thin plate 100. Then, the tapered portion 18 of the screw 10 is screwed into the thin plate 100 through the through hole 210 of the member to be fastened 200 (FIG. 5).

During the screwing of the screw 10, an upward force is applied to the thin plate 100 from the spiral protrusion 56 at the penetrating portion of the thin plate 100. In the reference example, when the screw 10 is screwed into the thin plate 100, the thin plate 100 is not sufficiently bent downward, so that at least a part of the thin plate 100 is upward (toward the head 52) at the penetrating portion of the thin plate 100. It may be bent toward (see FIG. 5). As a result, a burr 104 may be generated at the penetrating portion of the thin plate 100, or a portion 106 protruding upward may be generated. The burr 104 and the protruding portion 106 lift the member to be fastened 200 from the thin plate 100, which leads to insufficient fixing strength of the member to be fastened 200.

In particular, if the pitch of the spiral protrusions 56 is larger than the thickness of the thin plate 100, the thin plate 100 enters the groove between the spiral protrusions 56, so that the thin plate 100 is moved upward by the force from the male screw portion 54. It becomes easy to bend toward.

In the screw according to the present embodiment, since the thin plate 100 is sufficiently bent downward by the tapered portion 18 before the spiral protrusion 16 engages with the thin plate 100, it is easy to avoid the problem described in the reference example.

As mentioned above, although the content of the invention has been disclosed through embodiments, the statements and drawings that form part of this disclosure should not be understood to limit the invention. This disclosure reveals to those skilled in the art various alternative embodiments, examples and operational techniques. Therefore, the technical scope of the present invention is defined only by the matters specifying the invention relating to the reasonable claims from the above description.

For example, in the above embodiment, the screw 10 is a so-called "single screw" having one spiral protrusion 16. Instead, the screw 10 may be a so-called "multi-threaded screw" having a plurality of spiral protrusions 16.

Further, the screw 10 according to the above embodiment may be used together with a washer or packing, for example. In this case, the distance L2 between the spiral protrusion 16 and the head 12 may be larger than the above-mentioned numerical range. For example, the distance L2 may be a value obtained by adding a value of 10 mm or less, preferably 6.0 mm or less, and more preferably 4.5 mm or less to the thickness of the washer or packing.

10 Screw 12 Head 14 Male screw part 16 Spiral protrusion 18 Tapered part

Claims (5)

A male screw part with a spiral protrusion and
It has a tapered portion on the tip side of the male screw portion, and has a tapered portion.
The spiral protrusion is not provided on the tapered portion, and the spiral protrusion is not provided.
A screw in which the diameter of the male screw portion on a plane orthogonal to the rotation axis of the screw is equal to or larger than the pitch of the spiral protrusion in the direction along the rotation axis. The screw according to claim 1, wherein the tip of the tapered portion is sharp. The screw according to claim 1 or 2, wherein the tapered portion has a shape that is rotationally symmetric with respect to the rotation axis. The screw according to any one of claims 1 to 3, wherein the tapered portion has a conical shape or a truncated conical shape. The screw according to any one of claims 1 to 4, wherein the pitch of the spiral protrusion is larger than the thickness of the plate to which the screw is fastened.

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