Screw screws and how to use screw screws

Abstract

To provide a screw capable of preventing deformation of a drive part on a head as much as possible, even when a screw head is hit to pierce the tip of a shank, and a method for using the screw, which increases construction efficiency by using the screw, which enables the screw to be vertically driven without wobbling when it is driven and which enables stable construction.SOLUTION: A screw comprises a head 11 having a concave drive part 11a1 to which a tool tip is fitted, and a body part 12 and a shank 13, which are provided on the other side of the drive part 11a1 of the head 11. The tip of the shank 13 is provided with a piercing part 13a. A main screw part 13b with a predetermined length is provided in the rear of the piercing part 13a, and a sub-screw part 13c is provided on the side of the body part 12 with a space from the main screw part 13b. A plurality of protrusions 11a2 is provided at predetermined intervals around the drive part 11a1 of the head 11.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a screw nail provided with a head having a concave drive portion into which a tool tip is fitted, and a shaft portion having a screw portion provided on the opposite side of the drive portion in the head, and a method of using the screw nail.

Background Art

[0002] As a screw nail, for example, there is a wood screw for joining woods such as a column material and a plate material (see, for example, Patent Document 1). This screw nail includes a shaft portion having a head formed on the base end side, a main screw portion formed on the tip end side of the shaft portion and fastened to a column material or the like during connection, and a sub screw portion formed under the neck of the head in the shaft portion and fastened to a plate material during connection.

[0003] When joining woods with such a screw nail, the tip end of the shaft portion (referred to as the drill blade tip portion in Patent Document 1) is pierced into the wood by hitting the head of the screw nail with a hammer or the like, and then a tool is inserted into the drive portion of the head into which the tool tip is fitted to rotate the screw nail to join the woods.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the screw nail disclosed in Patent Document 1 described above, usually, the head of the screw nail is hit with a hammer or the like to pierce the drill blade tip portion at the tip end of the shaft portion into the wood. Therefore, when hitting with a hammer or the like, the drive portion of the head of the screw nail may be deformed, and it may be impossible to insert a bit or the like into the drive portion, resulting in a problem that it becomes difficult to rotate the screw nail with a tool. [[ID=4%]]

[0006] Therefore, the present invention has been made in view of these problems, and aims to provide a screw that can prevent deformation of the drive unit even when the head of the screw is struck to pierce the tip of the shaft, and a method of using the screw that improves construction efficiency, allows for stable construction by driving the screw in vertically without wobbling, and enables stable construction. [Means for solving the problem]

[0007] To solve the aforementioned problems, the screw according to the present invention comprises a head with a concave drive portion into which the tool tip fits, and a shaft portion on the opposite side of the drive portion on the head, wherein the shaft portion has a threaded portion on its outer surface and a thrust portion at its tip, and the head On the side of the drive unit, Around the aforementioned drive unit Multiple protrusions are provided at predetermined intervals, while on the surface of the head facing the shaft, multiple cutting blades extending in the circumferential direction of the head with respect to the shaft are provided at predetermined intervals, and each of the multiple protrusions is provided such that it overlaps with part or all of the multiple cutting blades. It is characterized by the following: Furthermore, the method of using a screw according to the present invention is mentioned above The method is characterized by first striking the head of the screw to temporarily fasten the screw by thrusting the protruding part at the tip of the shaft into the object to be joined, and then fitting the tip of the tool onto the drive part of the screw and rotating it to drive the screw into the object to be joined and other objects to be joined that were temporarily fastened. [Effects of the Invention]

[0008] In the screw according to the present invention, since a projection is provided around the drive part in the head, even if the head of the screw is struck to pierce the tip of the shaft, the strike will be directed at the projection, making it difficult to deform the drive part. Furthermore, in the method of using the screw according to the present invention, the screw head is temporarily fixed to wood or the like by striking it with a hammer beforehand, and then the tip of a tool is fitted onto the drive part of the screw and rotated to drive the screw into the temporarily fixed object and other objects to be joined, thereby improving construction efficiency. In addition, by temporarily fixing the screw beforehand before driving it in, the wobble of the screw is eliminated during driving, making it possible to drive the screw in vertically and enabling stable construction. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of a screw thread according to an embodiment of the present invention. [Figure 2] (a) and (b) are a front view and a right side view of a screw screw according to an embodiment of the present invention, respectively. [Figure 3] (a) and (b) are a rear view and a left side view of a screw according to an embodiment of the present invention, respectively. [Figure 4] (a) to (c) are a plan view, a bottom view, and a cross-sectional view along line AA in Figure 4(a), respectively, of a screw screw according to an embodiment of the present invention. [Figure 5] (a) and (b) are enlarged plan views of the main part of section B in Figure 2(b) and enlarged cross-sectional views of the main part of section C in Figure 4(c), respectively. [Figure 6] This is an enlarged plan view of a screw screw according to an embodiment of the present invention. [Figure 7] This is an enlarged bottom view of a screw screw according to an embodiment of the present invention. [Figure 8] This is an explanatory diagram showing the positional relationship between the projection on the upper surface of the screw and the cutting blade for the head and the cutting blade for the underside of the neck on the back side of the screw according to an embodiment of the present invention. [Figure 9] (a) to (c) are explanatory diagrams showing the positioning of a screw according to the embodiment of the present invention, the state during temporary fastening, the state with the tool partially inserted, and the state after installation. [Figure 10](a) and (b) are explanatory diagrams showing usage examples of the screw nut according to an embodiment of the present invention. [Figure 11] (a) and (b) are explanatory diagrams showing other usage examples of the screw nut according to an embodiment of the present invention. [Figure 12] (a) and (b) are explanatory diagrams showing other usage examples of the screw nut according to an embodiment of the present invention. [Figure 13] (a) and (b) are explanatory diagrams showing other usage examples of the screw nut according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0010] Hereinafter, the screw nut 1 according to the embodiment of the present invention and the method of using the screw nut 1 will be described in detail with reference to the accompanying drawings. Note that the embodiment described below is merely an example of the present invention including its dimensions and the like, and the present invention is not limited to the following embodiment and can be appropriately changed within the scope of the technical idea of the present invention.

[0011] The screw nut 1 according to the embodiment of the present invention is configured to include a head portion 11, a lower neck portion 12, and a shaft portion 13 as shown in FIGS. 1 to 4.

[0012] (Head portion 11) The head portion 11 has a predetermined thickness and is substantially circular in plan view as shown in FIGS. 1 to 8 and the like. It has an upper surface 11a on the side opposite to the lower neck portion 12 and the shaft portion 13, and a back surface 11b on the side of the lower neck portion 12 and the shaft portion 13. On the upper surface 11a, as shown in FIG. 5(b), FIG. 6, etc., a driving portion 11a1 that is square and concave in plan view into which the tip of a tool (not shown), such as a square bit, fits is provided. Around the driving portion 11a1, eight protrusion portions 11a2 are provided at predetermined intervals on an arc at intervals of 45 degrees centered on the driving portion 11a1.

[0013] The eight protrusions 11a2 are each provided so as to protrude from the upper surface 11a of the head 11, and are radially provided in a shape such that their width becomes narrower and their height also becomes lower as they move farther away from the center of the drive part 11a1 in a plan view.

[0014] Since each protrusion 11a2 has a wider width and a higher height as it approaches the concave drive part 11a1, even if the eight protrusions 11a2 are struck and each protrusion 11a2 is crushed when the head 11 is struck with a hammer or the like, deformation of the concave drive part 11a1 can be reliably prevented.

[0015] On the other hand, on the back surface 11b side of the head 11, eight cutting edges 11b1 for the head are provided at equal intervals of 45 degrees with respect to the center of the head 11 as shown in FIG. 7 and the like. Among the eight cutting edges 11b1 for the head, every other four cutting edges 11b1 are configured to be continuous with four cutting edges 12a1 for the neck bottom provided at 90-degree intervals on the side surface 12a of the neck bottom part 12 as will be described later.

[0016] The eight cutting edges 11b1 for the head are provided so as to form an angle of, for example, about 40 degrees with respect to the radial direction rather than in the radial direction with respect to the center of the head 11 in order to efficiently cut the wood that contacts the back surface 11b of the head 11 as shown in FIG. 7 and the like. Generation of burrs can be suppressed by the cutting edges 11b1 for the head, cracking of the wood when the wood contacts the back surface 11b of the head 11 can be prevented, and the wood surface and the upper surface 11a of the head 11 can be made flat. In addition, since there is an effect that cutting can be efficiently performed by the cutting edges 11b1 for the head, it has become easier to cope with preventing cracking of the wood and making the wood surface and the upper surface 11a of the head 11 flat even for hard wood that is difficult to cut.

[0017] Further, when the head 11 is struck with a hammer or the like, a large external force acts on the protrusion 11a2 that the hammer or the like hits, and not only the protrusion 11a2 but also the head 11 around the protrusion 11a2 is likely to be deformed. Therefore, as shown in FIG. 8, each of the eight cutting edges 11b1 for the head is provided so as to partially overlap with each of the eight protrusions 11a2 on the upper surface 11a side of the head 11.

[0018] Therefore, the overlapping portions of the eight cutting blades 11b1 for the head and the eight protrusions 11a2 become thicker than the thickness of the head 11 due to the thickness of each component, thus improving the strength by the amount of thickness increased.

[0019] Furthermore, because the eight cutting blades 11b1 and eight protrusions 11a2 for the head are arranged in a balanced manner, a stable shape can be manufactured.

[0020] In addition, increasing the circumference and thickness of the head 11 makes it easier to strike with a hammer and maintains the strength of the head 11, but of course, it is also acceptable to make it smaller in diameter and thinner in thickness. Furthermore, increasing the thickness of the head 11 allows for a deeper drive section 11a1 into which the tool bit is inserted, improving bit fitting and reducing the stress on the head 11 when working with tools such as impact drivers.

[0021] (Lower neck 12) The neck portion 12 is the part provided between the head portion 11 and the shaft portion 13, as shown in Figures 1 to 5, and is formed in the shape of a frustocone, with the outer diameter gradually increasing from the rear end of the shaft portion 13 toward the back surface 11b of the head portion 11.

[0022] On the inclined side surface 12a of the neck portion 12, as shown in Figures 5, 7, and 8, four neck-mounted cutting blades 12a1 are provided so as to be continuous with four of the eight head cutting blades 11b1 on the back surface 11b of the head portion 11, spaced at 90-degree intervals with one blade in between, thereby improving the efficiency of chip removal.

[0023] (Shaft portion 13) As shown in Figures 1 to 3, the shaft portion 13 has a protruding portion 13a at its tip, a main threaded portion 13b with a thread pitch of P1 provided in conjunction with or adjacent to the protruding portion 13a, and a secondary threaded portion 13c with a thread pitch of P2 provided on the head 11 side at a distance from the main threaded portion 13b.

[0024] Here, a thinner shaft diameter (outer diameter) for the shaft portion 13 improves the construction speed, but if the shaft portion 13 is made too thin, it will be prone to buckling when the head portion 11 is struck with a hammer or the like, so it is better to have a diameter of, for example, 5 mm.

[0025] The screw 1 of this embodiment is used, for example, to join two or three or more pieces of wood, as will be described later. By setting the relationship between the pitch P1 of the main thread portion 13b and the pitch P2 of the secondary thread portion 13c to P1 > P2, the amount of penetration (penetration length) per rotation of the screw 1 is made greater for the main thread portion 13b than for the secondary thread portion 13c, thereby pulling the pieces of wood to be joined together.

[0026] <Method of using the screw 1 of the embodiment> Next, the method of using the screw 1 of the embodiment configured as described above will be explained with reference to the drawings.

[0027] First, as shown in Figure 9(a), if the pieces of wood to be joined are the first piece of wood 2 and the second piece of wood 3, the protruding part 13a at the tip of the shaft portion 13 of the screw screw 1 of the embodiment is placed against the first piece of wood 2, and the upper surface 11a side of the head 11 of the screw screw 1 is struck with a hammer 4 or the like to push the protruding part 13a into the first piece of wood 2 and perform temporary fastening to determine the position.

[0028] In this case, performing the temporary fastening work on the ground rather than at a height ensures safety and maintains construction accuracy. Furthermore, the screw 1 is not a spiral screw all the way to the tip of the shaft 13, but rather has a blade-like shape without threads, as shown in Figures 1 to 4. This allows it to penetrate the wood, making temporary fastening easier. Also, when installing with an impact driver, a screw would create a spiral hole, but the blade shape allows for significant cutting of the wood, effectively creating a pre-drilled hole simultaneously with rotation. This reduces pressure on the wood during installation, making it less likely to crack. In addition, friction is reduced, which can lead to an improvement in installation speed.

[0029] Furthermore, in the screw 1 of this embodiment, eight protrusions 11a2 are provided around the concave drive unit 11a1 into which the tool tip fits on the upper surface 11a of the head 11. Therefore, when the upper surface 11a of the head 11 is struck hard with a hammer 4, the hammer 4 will always hit the protrusions 11a2 around the drive unit 11a1 before hitting the upper surface 11a of the head 11 around the drive unit 11a1.

[0030] Therefore, although the projection 11a2 struck by the hammer 4 may deform, the possibility of deformation of the upper surface 11a of the head 11 is extremely low compared to the case where the projection 11a2 is not provided, thus preventing deformation of the concave drive unit 11a1.

[0031] In particular, even if the head 11 is struck with a hammer or the like and each projection 11a2 is crushed, the projection 11a2 is shaped so that it becomes taller and wider the closer it is to the drive unit 11a1, thereby more reliably preventing deformation of the drive unit 11a1.

[0032] Furthermore, since the protrusions 11a2 are arranged radially, even if a hammer or the like strikes only a part of the drive unit 11a1 rather than the entire surface, the impact will first hit the individual protrusions 11a2, preventing deformation of the drive unit 11a1. In addition, even if the impact is at an angle, the height of each protrusion 11a2 decreases as it approaches the circumference, making it less likely to hit the drive unit 11a1, thus preventing deformation of the drive unit 11a1.

[0033] Furthermore, when manufacturing this screw 1, the head 11 is formed by cold forging. For example, if only the cutting blades 11b1 for the head are provided on the back surface 11b side of the head 11, the material will try to take the surrounding material to form the convex cutting blades 11b1 during cold forging, resulting in a polygonal shape rather than a perfect circle. However, by providing the protrusions 11a2 on the top surface 11a side and the eight cutting blades 11b1 on the back surface 11b side radially on both the front and back surfaces, it becomes possible to make the head 11 closer to a perfect circle.

[0034] Furthermore, as shown in Figure 8, each of the eight protrusions 11a2 is provided so as to partially overlap with each of the eight cutting blades 11b1 for the head on the back surface 11b of the head 11. Since the overlapping portion is thicker, even if each protrusion 11a2 is crushed, the increased thickness improves the strength, preventing deformation of the drive unit 11a1. In addition, when forming the head 11, the impact on the mold is reduced, thus reducing the burden and extending the life of the mold.

[0035] After temporarily inserting the protruding portion 13a of the screw 1 of the embodiment into the first piece of wood 2 using the hammer 4 as described above, the tip of a tool (not shown) such as a bit attached to the rotating shaft of an electric tool such as an impact wrench is fitted onto the drive portion 11a1 of the head 11 and rotated to insert the main thread portion 13b at the tip of the shaft portion 13 into the first piece of wood 2, as shown in Figure 9(b).

[0036] When the rotating shaft of an electric tool such as an impact wrench is rotated further, as shown in Figure 9(c), the main threaded portion 13b at the tip of the shaft 13 penetrates to the second piece of wood 3, and the secondary threaded portion 13c at the rear end of the shaft 12 penetrates to the first piece of wood 2, thereby joining the first piece of wood 2 and the second piece of wood 3.

[0037] In this embodiment, the screw thread 1 has a screw pitch P1 of the main thread portion 13b that is greater than the screw pitch P2 of the secondary thread portion 13c. As a result, the amount of penetration of the main thread portion 13b into the second piece of wood 3 is greater than the amount of penetration of the secondary thread portion 13c into the first piece of wood 2. Therefore, the first piece of wood 2 and the second piece of wood 3 can be pulled together and joined firmly.

[0038] <Example of use of screw 1 in the embodiment> Next, an example of how to use the screw 1 of the embodiment configured as described above, including the fitting pattern, will be explained with reference to the drawings.

[0039] Figure 10(a) shows an example in which the screw screw 1 of the embodiment is used to join the rafter 2a and the beam 3a, and Figure 10(b) shows an example in which the screw screw 1 of the embodiment is used to join the rafter 2a and the beam 3a when a facing material 2b is provided on the upper surface of the rafter 2a.

[0040] In Figure 10(a), the main threaded portion 13b on the protruding portion 13a side of the screw 1 of the embodiment stops at the beam 3a, and the secondary threaded portion 13c on the head 11 side stops at the rafter 2a, and the difference in their respective pitches P1 and P2 pulls the rafter 2a and beam 3a together for joining. In Figure 10(b), however, since there is a facing material 2b on top of the rafter 2a, the secondary threaded portion 13c on the head 11 side stops at both the rafter 2a and the facing material 2b.

[0041] Figure 11(a) shows an example of using the screw 1 of the embodiment to diagonally join an insulating panel 2c to a beam 3a, and Figure 11(b) shows an example of using the screw 1 of the embodiment to join an insulating panel 2c to a structure in which a beam 3a is provided on a base 3b via a column 3c.

[0042] In Figure 11(a), the main threaded portion 13b on the protruding portion 13a side of the screw 1 in the embodiment stops at the beam 3a, and the secondary threaded portion 13c on the head 11 side stops at the insulation panel 2c, and the difference in their respective pitches P1 and P2 pulls the insulation panel 2c and the beam 3a together for joining. In Figure 11(b), in the upper screw 1, the main threaded portion 13b stops at the beam 3a and the secondary threaded portion 13c stops at the insulation panel 2c, while in the lower screw 1, the main threaded portion 13b stops at the base 3b and the secondary threaded portion 13c stops at the insulation panel 2c, resulting in a pulling effect between the insulation panel 2c and the beam 3a and base 3b, respectively.

[0043] Although not shown in the diagram, the insulation panel 2c may of course be made of wood-based materials such as CLT (cross-laminated timber), LVL (laminated veneer lumber), or laminated timber. In addition, although the insulation panel 2c is installed vertically in Figure 11(b), the insulation panel 2c or the aforementioned wood-based materials may be installed horizontally and used as flooring.

[0044] Figure 12(a) shows an example in which the screw screw 1 of the embodiment is inserted horizontally toward the column 3c into the brace 2d provided at the joint between the base 3b and the column 3c to join the brace 2d and the column 3c, while Figure 12(b) shows an example in which the screw screw 1 of the embodiment is inserted vertically toward the base 3b into the brace 2d provided at the joint between the base 3b and the column 3c to join the brace 2d and the base 3b.

[0045] In Figure 12(a), the main threaded portion 13b of the screw 1 in the embodiment stops at the column 3c, and the secondary threaded portion 13c stops at the brace 2d, and the difference in their respective pitches P1 and P2 pulls the column 3c and the brace 2d together for connection. In Figure 12(b), the main threaded portion 13b of the screw 1 in the embodiment stops at the base 3b, and the secondary threaded portion 13c stops at the brace 2d, and the difference in their respective pitches P1 and P2 pulls the base 3b and the brace 2d together for connection.

[0046] Although not shown in the diagram, the screw 1 of the embodiment may be driven horizontally toward the column 3c to join the brace 2d and the column 3c, and then the screw 1 may be driven vertically toward the base 3b to join the brace 2d and the base 3b. Alternatively, the screw 1 of the embodiment may be driven at an angle to join the brace 2d to the column 3c or beam 3a (or base 3b, etc.). In any case, the joining method is sufficient as long as the brace 2d and structural members such as the column 3c or beam 3a are joined with the screw 1 of the embodiment.

[0047] Figure 13(a) shows an example in which the screw screw 1 of the embodiment is used when joining the facing material 2b to the beam 3a (or base 3b, etc.), and Figure 13(b) shows an example in which the end face of the facing material 2b is abutted against the beam 3a (or base 3b, etc.), and the lower surface of the facing material 2b is supported from below by the support member 3d, and the screw screw 1 of the embodiment is inserted vertically from the facing material 2b toward the support member 3d, and horizontally from the support member 3d toward the beam 3a (or base 3b, etc.) to make the joint.

[0048] In Figure 13(a), the main threaded portion 13b of the screw 1 in the embodiment stops at the beam 3a (or base 3b, etc.), and the secondary threaded portion 13c stops at the facing material 2b, and the difference in their respective pitches P1 and P2 allows the beam 3a (or base 3b, etc.) and the facing material 2b to be pulled together and joined. In Figure 13(b), the main threaded portion 13b of the vertical screw 1 stops at the support member 3d, and the secondary threaded portion 13c stops at the facing material 2b, and the difference in their respective pitches P1 and P2 allows the facing material 2b and the support member 3d to be pulled together and joined. On the other hand, the main threaded portion 13b of the horizontal screw 1 stops at the beam 3a (or base 3b, etc.), and the secondary threaded portion 13c stops at the support member 3d, and the difference in their respective pitches P1 and P2 allows the support member 3d and the beam 3a (or base 3b, etc.) to be pulled together and joined.

[0049] <Summary of the screw thread 1 according to the embodiment of the present invention> As described above, in the screw screw 1 of the embodiment of the present invention, since a projection 11a2 is provided around the drive portion 11a1 in the head 11, even when the head 11 of the screw screw is struck to pierce the tip of the shaft portion 13, the projection 11a2 is struck instead, and deformation of the concave drive portion 11a1 can be prevented as much as possible.

[0050] Furthermore, in the screw 1 of the embodiment according to the present invention, eight projections 11a2 are provided in an arc at predetermined intervals, with a 45-degree interval between them, centered on the drive unit 11a1.

[0051] Therefore, when plating the screw 1 of the embodiment, the plating agent flows on the upper surface 11a side of the head 11 in the direction of passing through the gap between the concave drive portion 11a1 and the projection portion 11a2, or in the opposite direction. This makes it possible to reliably plate the outer surface of the screw 1, improving the appearance and rust prevention performance of the screw 1. Furthermore, since the plating agent does not accumulate in the concave drive portion 11a1, the quality of the screw 1 can also be improved.

[0052] Furthermore, in the screw 1 of the embodiment of the present invention, eight cutting blades 11b1 for the head are provided at predetermined intervals on the back surface 11b side of the head 11 where the shaft portion 13 is provided, extending in the circumferential direction of the head 11 with the shaft portion 13 as the center, and a plurality of protrusions 11a2 provided on the upper surface 11a side are provided such that some or all of them overlap with the eight cutting blades 11b1 for the head.

[0053] Therefore, the projection 11a2 is thickened by the cutting blade 11b1 on the opposite side of the head, improving its strength. In this respect as well, deformation of the drive unit 11a1 can be prevented as much as possible when the projection 11a2 of the head 11 of the screw 1 is struck with a hammer or the like.

[0054] Furthermore, the increased thickness of the head 11 due to the multiple protrusions 11a2 reduces the impact on the mold when manufacturing the head 11 of the screw thread 1, thereby reducing the burden and extending the life of the mold.

[0055] Furthermore, in the method of using the screw 1 according to the embodiment of the present invention, the screw 1 is temporarily fixed to the object to be joined, such as wood (for example, the first piece of wood 2 in the case of Figure 9), by striking the screw 1 with a hammer or the like on the ground, the object to be joined with the screw 1 temporarily fixed is moved to a high place, the tip of the tool is fitted onto the drive unit 11a1 of the screw 1, and it is rotated with an electric tool such as an impact wrench, and the screw 1 is driven in continuously into the object to be joined with the screw 1 temporarily fixed and into other objects to be joined (for example, the second piece of wood 3 in the case of Figure 9), thereby improving construction efficiency. In addition, by driving the screw 1 according to the embodiment of the present invention on the ground, the wobble of the screw 1 during driving is eliminated, so it becomes possible to drive the screw 1 vertically, enabling stable construction and safe work at high places. [Explanation of Symbols]

[0056] 1 Screw 11 Head 11a Top surface 11a1 Drive unit 11a2 Protrusion 11b Back side 11b1 Cutting blade for head 12 Lower part of the neck 12a side 12a1 Cutting blade for under neck 13. Shaft 13a Pierce part 13b Main thread section 13c secondary thread section 2. First piece of wood (object to be joined) 2a Rafter 2b Surface material 2c insulation panel 2D bracing 3. Second piece of wood (other objects to be joined) 3a beam 3b Base 3c pillar 3d receiving material

Claims

1. The tool comprises a head with a concave drive section into which the tool tip fits, and a shaft section on the opposite side of the drive section of the head, The shaft portion is provided with a threaded portion on its outer surface and a protruding portion at its tip. On the surface of the head facing the drive unit, a plurality of protrusions are provided at predetermined intervals around the drive unit, Multiple cutting blades are provided at predetermined intervals on the surface of the head facing the shaft portion, extending in the circumferential direction of the head with respect to the shaft portion. The screw is characterized in that the plurality of protrusions are provided such that they overlap with the plurality of cutting blades and some or all of them.

2. A method for using a screw screw as described in Claim 1, characterized in that the head of the screw screw is struck in advance to thrust the protruding portion at the tip of the shaft into the object to be joined, thereby temporarily fastening the screw screw, and then the tip of a tool is fitted onto the drive portion of the screw screw and rotated to drive the screw screw into the object to be joined to which it was temporarily fastened and into other objects to be joined.

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