Water cutoff tool for screw fastening part

Abstract

To provide a water cutoff tool capable of ensuring sufficient water cutoff at a screw fastening portion of an outer wall material to a substrate material.SOLUTION: A water cutoff tool 1 for a screw fastening part comprises: an annular packing part 2 provided with a through hole 4 with a diameter larger than an outer diameter of a thread d; and a leg part 3 provided so as to extend along an axial core direction of the through hole 4 on a surface of the packing part 2 opposite a surface where a head b of a screw a overlaps. A surface of the leg part 3 located so as to face the axial core direction of the through hole 4 is made into a screwing surface 5 for the thread d. An end surface 5' of the screwing surface 5 of the leg part 3 facing the packing part 2 is provided so as to face a part of the radial inside of the through hole 4.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This invention relates to a water stopper for ensuring waterproofing of screw fastening parts, specifically to a water stopper for screw fastening parts that is used when attaching an external component to the exterior wall of a building during renovations of the building, and when a screw is screwed into a threaded hole formed in a base material on the exterior wall and filled in after the external component is removed, and that makes the threaded part of the screw screwed into this threaded hole waterproof. [Background technology]

[0002] For example, in a building where the exterior walls are formed by using a relatively thin steel base material to which the exterior wall material, which is the fastening member, is fixed with screws, when temporary scaffolding is to be constructed on the outside of the exterior wall for renovations, etc., the standing strength of the temporary scaffolding is ensured by the base material of the exterior wall.In this case, an external connector is screwed and fixed to the base material of the exterior wall, and the temporary scaffolding and the exterior wall are connected via this connector.

[0003] There are two ways to fasten a connector to a base material: one is to drill a new screw hole from the exterior wall material to the base material with a diameter that matches the root diameter of the screw to be used, and then screw the connector into this pilot hole; the other is to remove the existing screw that fastens the exterior wall material from the base material and then use the remaining screw hole in the base material, or to enlarge the diameter of this screw hole and use it as a pilot hole to screw the connector into.In either case, after the connector is removed, the remaining screw holes in the exterior wall material and base material must be filled with new screws to prevent rainwater from seeping inside the room.

[0004] When fastening exterior wall materials to exterior walls that use a relatively thin steel base material, the materials are fastened with screws at multiple points to withstand natural wind and rain. However, when trying to maintain the standing strength of temporary scaffolding on the exterior wall, a greater load may be placed on the screws fixing the exterior wall material. Therefore, the screws used to fasten the connecting material must be larger in diameter than the screws used to fasten the exterior wall material to the base material. For this reason, the pilot holes drilled from the exterior wall material to the base material when fastening the connectors will be larger in diameter than the screws used to fasten the exterior wall material, and naturally the screw holes formed by screwing the screws into these pilot holes will be larger in diameter than the screw holes used to fasten the exterior wall material.

[0005] In addition, when installing a connector, in addition to drilling new pilot holes in the exterior wall material and base material as described above, the screw that secures the exterior wall material is removed, the screw hole is enlarged to a larger diameter pilot hole, and a larger diameter screw is screwed into this pilot hole.

[0006] Under these conditions of fastening the connectors, when the temporary scaffolding is dismantled after construction is completed and the connectors are removed along with the screws, larger diameter screw holes will remain in the exterior wall material and base material at the areas where the connectors were removed, compared to the screws used to fasten the exterior wall material.

[0007] A simple way to close large diameter screw holes is to use the large diameter screws used to attach the connectors and screw them into the screw holes in the exterior wall material and the base material to close them.

[0008] However, in the exterior wall material fixing structure of exterior walls constructed under the conditions described above, it is common to use a large number of screws of the same size to fix the exterior wall material to the base material, and to arrange them in a regular pattern in order to improve the aesthetic appearance of the finished exterior surface of the exterior wall.

[0009] Therefore, if the large-diameter screw holes left after removing the connectors are closed with screws that are larger than the screws used to secure the exterior wall material, the heads of the screws in the closed area will be larger than the heads of the screws used to secure the exterior wall material, and will stand out in part against the arrangement of the screw heads, destroying the uniformity of the head arrangement and damaging the aesthetic appearance of the exterior wall.

[0010] Therefore, to prevent deterioration of the aesthetic appearance, it is necessary to make it possible to close the large-diameter screw holes formed in the exterior wall material and base material with small-diameter screws of the same size as the screws used to fasten the exterior wall material, and to make the head sizes aligned on the outer surface of the exterior wall the same.

[0011] However, if one attempts to close large-diameter screw holes formed in the exterior wall material and base material with screws of the same size as the screws used to secure the exterior wall material, the screw shank diameter will be smaller than the large-diameter screw hole, making it impossible to screw the screw into place.To solve this problem, an auxiliary tool has been proposed that can be inserted into the large-diameter screw hole before the screw is screwed in, thereby compensating for the difference in diameter between the large-diameter screw hole and the smaller diameter screw shank, allowing smaller screws to be secured in the large-diameter screw hole.

[0012] Such conventional auxiliary devices can only be used to secure small screws in large diameter screw holes, and when used to fill screw holes formed in the outer wall of a structure with screws, they are unable to ensure watertightness in the threaded portion. Therefore, there is currently a need for an auxiliary device that can be used in such locations and has a structure that can ensure sufficient watertightness in the screwed portion.

[0013] This is because the large diameter screw holes that remain after the screws have been removed are not only larger than the threaded holes of the screws that secure the exterior wall material, but also contain screws that support the temporary scaffolding, and the inner diameter precision is reduced as the screws become larger and deformed when they support the load or when they are attached and removed.In addition, when working at heights such as on scaffolding, it is difficult and awkward to drill large diameter pilot holes accurately from the exterior wall material to the base material, which in turn results in the diameter of the pilot holes becoming larger.

[0014] For this reason, even if a screw of the same size as the screw used to fasten the exterior wall material is screwed into a large-diameter screw hole using an auxiliary tool for large-diameter screw holes, it is difficult for this auxiliary tool to reliably compensate for the enlargement caused by the reduced precision of the large-diameter screw hole, and there are cases where the watertightness of the threaded part of the screw threaded between the large-diameter screw hole and the auxiliary tool cannot be fully guaranteed.For this reason, in order to prevent rainwater from entering the room at the threaded part when the screw is threaded again, it is necessary to use a common ring-shaped gasket placed between the screw head and the exterior wall material.

[0015] Here, the structures of the conventional screw fastening aids cited in Patent Documents 1 to 4 and the problems therewith will be specifically described.

[0016] The auxiliary device shown in Publication 1 is a ring-shaped elastic gasket that is inserted onto the shank of the screw. It is sandwiched between the underside of the screw head and the exterior wall material, and is tightened firmly with a strong torque until it is pushed out from the underside of the head, as shown in Figure 3 of Publication 1. However, when the base material is fragile, such as a thin steel plate, and a screw hole is closed by screwing in a screw, as in the application of the present invention, the female thread of the screw hole on the base material into which the screw threads cannot withstand sufficient torque. For this reason, the tightening force of the gasket must be set loosely to take this into consideration, and as a result, the screw will not be tightened sufficiently, and it will not be possible to completely prevent rainwater from entering the screw hole.

[0017] The auxiliary device in Publication 2 addresses the problems with the packing in Publication 1 by forming a tubular member integrally with the bottom of the packing, and as shown in Figure 3 of Publication 2, the tubular member is designed to be inserted into a screw hole. However, if the exterior wall material to be fastened is made of thin steel plate and is thin, and there is not enough distance between the exterior wall material and the base material, the tubular member will penetrate into the screw hole in the base material, preventing the screw from threading into the screw hole, and therefore making it impossible to properly join the screws in the first place.

[0018] It is also possible to set the height of the tubular member to match the thickness of the exterior wall material, but if the thickness of the exterior wall material is, for example, about 1 mm, the height of the tubular member will be too low to ensure the height required for watertightness, and therefore the effect of providing the tubular member cannot be expected.

[0019] The screw tightening aid in Publication 3 has a structure in which legs are provided on the underside of the packing part, and rather than relying solely on the screw and screw hole threading to crimp the packing part, the legs are wedged into part of the space between the screw and the screw hole, making it possible to ensure the necessary tightening torque even in situations where the screw is weak and the screw hole cannot be made sufficiently accurate.

[0020] However, this screw fastening aid is designed only to ensure sufficient tightening torque, and no consideration has been given to waterproofing the screw joint, so naturally it does not provide waterproofing functionality as is.

[0021] This is because, as described in paragraph

[0015] of Publication 3, "the through-hole of the packing part is set to a diameter that allows the tip of the shank of the tapping screw to be press-fitted into it when used in combination," and under these conditions, when the leg is pulled in as if sucked in the direction of screw entry by tightening the screw, there is no escape route between the through-hole of the packing part and the shank of the screw, and the part around the through-hole of the packing part that is pulled by the leg will deform and break.

[0022] The screw tightening aids that cause this type of problem in the packing section are not intended to provide watertight performance, but rather to integrate the screw and aid by inserting the legs into the screw hole, so that even if deformation or breakage occurs after screwing, there will be no particular problems with the fastening.However, as mentioned above, deformation or breakage occurs in the packing section, so it is not possible to achieve the watertightness that is the objective of this invention.

[0023] The screw tightening aid shown in Figures 4 and 5 of Publication 4 has a structure in which a retaining piece is provided between the screw shaft and the screw hole to prevent the screw from loosening, and the retaining piece is pulled between the screw and the screw hole in the insertion hole of the base (exterior wall material) which is formed integrally with the retaining piece, creating a gap that allows deformation of the base.

[0024] However, such screw tightening aids are constructed simply to provide a gap to allow deformation of the base, and therefore the base, which is integrated with the retaining piece, has a small contact area with the screw head, which means that sufficient friction cannot be obtained, resulting in the problem of co-rotation.

[0025] Normally, if a thin steel plate comes into contact with a gasket or a plastic molded product such as the base of Publication 4 and rotates together with the screw, the contact point between the edge of the thin steel plate and the plastic molded product will be cut, so Publication 4 addresses this by providing a separate protrusion to prevent rotation.

[0026] However, in the case of the gasket portion of a water stop device used on exterior wall materials such as thin steel plates, as in the present invention, having the anti-rotation convex portion protruding from the screw head is not only aesthetically undesirable, but providing a recess in the exterior wall material to receive the anti-rotation convex portion not only results in a significant increase in the cost of the exterior wall material, but also causes the wall to lift if there is a base on the back of the exterior wall material, making it unfeasible in practice. [Prior art documents] [Patent documents]

[0027] [Patent Document 1] Japanese Patent Application Laid-Open No. 9-100915 (with a specially designed inner diameter shape of the packing) [Patent Document 2] Japanese Utility Model Application Publication No. 60-122430 (a cylindrical member attached to the outer wall side of the packing) [Patent Document 3] Japanese Patent Application Laid-Open No. 11-311227 (Pad to assist in fixing screws) [Patent Document 4] Japanese Utility Model Application Publication No. 61-61309 (Example of a locking piece that bites into the female thread of a nut and the insertion bolt) Summary of the Invention [Problem to be solved by the invention]

[0028] Therefore, the object of this invention is to provide a water-stopping device that can ensure sufficient water-tightness in the screwed-in portion when a large-diameter screw hole remaining after removing an external component that has been screwed and fixed to the base material of an exterior wall during renovation of a structure, etc., is filled with a screw smaller in size than the screw hole. [Means for solving the problem]

[0029] In order to solve the above-mentioned problems, the invention of claim 1 is a watertight device for a screw fastening part, which comprises an annular packing part having a through hole with a diameter larger than the outer diameter of the threads formed on the shank part for inserting the shank part of a screw to be used in combination therewith, and a leg part provided on the face of the packing part opposite the face where the screw head overlaps, so as to extend long along the axial direction of the through hole, wherein the face of the leg part that faces the axial direction of the through hole becomes the threaded engagement face for the threads formed on the shank part of the screw, and the end of the leg part's threaded engagement face on the packing part side is arranged to face the radially inward side of the through hole at a position on the inner surface of the through hole, and the relationship between the threaded engagement face and a part of the inner surface of the through hole that is located opposite the threaded engagement face across the axis of the through hole is set so that the distance between an imaginary extension line in the axial direction at the opposite position and the threaded engagement face is equal to or wider than the outer diameter of the thread of the screw.

[0030] The invention of claim 2 is such that, when the inner diameter of the through hole of the packing portion is φD and the distance from an imaginary axial extension line of a portion of the inner surface of the through hole that is positioned opposite the screw-engagement surface to the screw-engagement surface is D', φD > D'.

[0031] The invention of claim 3 is such that, when the distance from an imaginary axial extension line of the portion of the inner surface of the through hole that is positioned opposite the threaded surface to the threaded surface is D' and the outer diameter of the thread of the screw used in combination is φd, D'≧φd (D'max ≒ 0.5 mm + φd).

[0032] According to a fourth aspect of the present invention, the center of the through hole is eccentric with respect to the center of the outer periphery of the packing portion.

[0033] The invention of claim 5 is such that the eccentric direction of the through hole relative to the packing portion is set so that the center of the through hole is located on the radial center line that is perpendicular to the screwing surface of the leg portion and passes through the center of the outer diameter of the packing portion, on the opposite side of the screwing surface across the center of the outer diameter of the packing portion.

[0034] The invention of claim 6 is such that when the shank of the screw is inserted into the through hole of the packing part, gaps are formed on both sides of the shank of the screw between the inner surface of the through hole and the surface of the shank of the screw to allow deformation of the packing part.

[0035] The invention of claim 6 is such that when the shank of the screw is inserted into the through hole of the packing part, gaps are formed on both sides of the shank of the screw between the inner surface of the through hole and the surface of the shank of the screw to allow deformation of the packing part.

[0036] Here, the water-stopping device is formed by integrally molding the packing part and the leg part using a synthetic resin or rubber-based material that generates a water-stopping function in the compressed packing part, and the leg part has a length approximately the same as the shank of the screw to be used in combination with it, and its cross-sectional shape is approximately semicircular with an arc-shaped outer periphery, and the flat side facing the shank of the screw inserted into the through hole of the packing part is formed as a shallow recessed groove that circumscribes the shank of the screw, and the flat bottom surface of this recessed groove becomes the threading surface of the screw thread when the screw is screwed in. [Effects of the Invention]

[0037] According to this invention, the through hole provided in the annular packing portion is made larger in diameter than the outer diameter of the thread, and legs are provided on this packing portion so that the end of the thread engagement surface faces radially inward from the inner surface of the through hole, and the distance between the part on the inner surface of the through hole opposite the thread engagement surface and the thread engagement surface is set to be equal to or wider than the outer diameter of the thread of the screw.Therefore, a gap is secured on the inside of the annular packing portion which is compressed when the screw is tightened, which can allow deformation.Therefore, even if the legs are pulled into the pilot hole by tightening the screw, the packing portion deforms in a way that ensures watertightness, and the packing portion can be firmly compressed.Furthermore, the space between the screw hole and the shank of the screw is sealed by the presence of the legs, so sufficient watertightness can be ensured in the fastening portion by the screw.

[0038] In addition, large diameter screw holes formed in the base material can be filled using existing screws or screws of the same size, so the heads of the screws that fill the screw holes in the exterior wall that are created after the external component is removed can be made to match the heads of the existing exterior wall fixing screws, which allows the heads of the screws on the outer surface of the exterior wall to be aligned and prevents a decrease in the appearance of the exterior wall.

[0039] Furthermore, by making the outer diameter of the packing part concentric with the through hole, making this through hole larger in diameter than the shank of the screw, and either having the thread engagement surface of the screw on the leg part face part of the inner periphery of the through hole, or by offsetting the center of the outer diameter of the packing part from the center of the through hole, it is possible to increase the outer rotational diameter of the packing part centered on the rotation axis of the screw, and also to increase the area of ​​the connection point between the packing part and the leg part where the greatest rotational force is generated.This increases the frictional force between the packing part and the exterior wall material, and the frictional force between the screw hole and the leg part when the screw is screwed in, thereby suppressing co-rotation of the watertight device and preventing breakage of the packing part and the leg part, thereby ensuring secure fixation of the screw. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a perspective view showing a first embodiment of a water stopper for a threaded fastening portion according to the present invention; [Figure 2] A side view of the water stopper with a part cut away [Figure 3] Enlarged front view from arrow (A)-(A) in Figure 2 [Figure 4] Enlarged longitudinal rear view of arrow (A)-(A) in Figure 2 [Figure 5] FIG. 2 is an enlarged longitudinal side view of the main part of the water stop device. [Figure 6] FIG. 10 is an enlarged longitudinal rear view showing a state in which a screw is inserted into a through hole provided in a packing portion of the water stop device before being tightened. [Figure 7] An enlarged longitudinal rear view showing the deformation that occurs in the packing when the screws are tightened, compared to Figure 6. [Figure 8] 1 is an enlarged front view showing a second embodiment of a water stopper for a threaded fastening portion according to the present invention; [Figure 9] FIG. 1 is a vertical cross-sectional side view showing a state in which the water stop device according to the present invention is used. DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0042] Figures 1 to 7 show a first embodiment of a water stop device 1 according to the present invention. The water stop device 1 comprises an annular packing portion 2 having a required thickness, and an axial leg portion 3 provided on the surface (back side) opposite to the surface on which the head b of the screw a to be used in combination overlaps with the packing portion 2. The packing portion 2 is disc-shaped with an outer diameter that is the same as or slightly smaller than the outer diameter of the head b of the screw a. By making the outer diameter larger in this way, it is possible to prevent the entire water stop device 1 from falling into the pilot hole for screwing in the screw when the pilot hole is vertical. Furthermore, a circular through hole 4 for inserting the shank c of the screw a is provided coaxially with the outer diameter of the packing portion 2, and the inner diameter of this through hole 4 is larger than the outer diameter of the thread d of the shank c of the screw a.

[0043] Here, as shown in Figure 9, the above-mentioned screw a is a reused screw that was screwed from the exterior wall material 9 into the base material 8 to secure the exterior wall material 9 in a structure where the exterior wall is constructed by fixing the exterior wall material 9 to the outside of the base material 8, or a screw of the same size.In contrast, the screw hole left in the base material 8 from the exterior wall material 9 after construction work, which is to be filled with screw a, is a large-diameter screw hole A, as shown by the dotted line in Figure 3, which was created by screwing in and then removing a large-diameter screw that is larger than the above-mentioned screw a.Therefore, the water stop device 1 is designed to compensate for the difference in diameter between the shank of screw a and the large-diameter screw hole A that serves as the pilot hole, so that a smaller-sized screw a can be screwed in and secured in the large-diameter screw hole A.

[0044] This water stop device 1 is formed using a synthetic resin or rubber-based material by integrally attaching a leg portion 3 to one side of a packing portion 2, and the leg portion 3 extends long along the axial direction of the through hole 4 and has a length approximately the same as that of the shank c of the screw a used in combination, and the end portion on the packing portion 2 side is connected to the packing portion 2 in a state where the end face faces a part of the inner circumference of the through hole 4.

[0045] The cross-sectional shape of the leg portion 3 is approximately semicircular with an arc-shaped outer periphery and a straight flat surface, and its width is approximately the same as or slightly narrower than the diameter of the through hole 4. The longitudinal center line of the flat surface in the cross section and the center line of the through hole 4 are parallel to each other, and the flat surface is at a right angle to the radial center line connecting the two center lines, and is provided in the packing portion 2 so as to be positioned opposite the center line of the through hole 4. This flat surface becomes the threading surface 5 of the thread d formed on the shank c of the screw a inserted into the through hole 4 of the packing portion 2.

[0046] As shown in Figure 4, the leg 3 has low raised edges 6 on both sides of the threaded surface 5, which essentially form the threaded surface 5 in the shape of a shallow groove, allowing the shank c of the screw a to fit stably against the threaded surface 5 of the leg 3. As shown in Figure 5, the relationship between the end of the leg 3 located on the packing portion 2 side and the connecting portion of the packing portion 2 is such that the inner surfaces of the raised edges 6 on both sides coincide with the inner circumference of the through hole 4, and the flat end face 5' of the threaded surface 5 faces radially inward from a part of the inner circumference of the through hole 4. The part of the end of the leg 3 other than the end faces 5' forms a connecting portion with the packing portion 2, and this connecting portion ensures the strength to withstand twisting that occurs between the packing portion 2 and the leg 3.

[0047] In such a joint between the packing part 2 and the leg part 3, the height dimension from the inner circumference of the through hole 4 of the end face 5' of the leg part 3 facing the through hole 4 is at its maximum approximately the height of the thread d of the screw a, so that most of the cross-sectional shape at the end of the leg part 3 is the joint part with the packing part 2, ensuring the strength of the joint part against torsion.

[0048] In the relationship between the through hole 4 of the packing portion 2, the threaded surface 5 of the leg portion 3, and the screw a, when the inner diameter of the through hole 4 is φD and the outer diameter of the thread d is φd, φD > φd, and in a direction perpendicular to the longitudinal direction of the shank c of the screw a used in combination, the distance D' from the threaded surface 5 facing the shank c of the screw a to the imaginary extension line of the part of the inner surface of the through hole 4 facing the threaded surface 5 across the axis of the shank c is φD > D' with respect to the diameter of the through hole 4, and further, with respect to the outer diameter φd of the thread d of the screw a, D' ≧ φd (D' max ≒ 0.5 mm + φd).

[0049] In this way, by making the distance D' the same as the outer diameter φd of the thread d of the screw a, or by making it larger by up to 0.5 mm, the thread d is prevented from coming into contact with the inner surface of the through hole 4 and the threaded surface 5, making the initial insertion work easier.When the screw a is screwed into the water-stop device 1 inserted into the large-diameter screw hole A, the thread d engages with part of the through hole 4 and part of the large-diameter screw hole A, and at the same time, the thread d engages with the threaded surface 5 of the leg 3, thereby ensuring a sufficient contact area between the thread d and the threaded surface 5 when the screw a is screwed in.

[0050] Furthermore, as shown in Figures 6 and 7, the inner diameter φD of the through hole 4 is made larger than the above-mentioned distance D', and this inner diameter φD is made larger than the outer diameter of the thread d. In this state, the end face 5' of the threading surface 5 is arranged so that part of it faces radially inward from the inner circumference of the through hole 4. When the shank c of the screw a is inserted into the through hole 4, gaps 7 are formed on both sides of the shank c of the screw a inside the through hole 4 to allow deformation of the packing portion 2. The packing portion 2, compressed by the head b when the screw a is tightened, deforms so as to escape toward the gaps 7, thereby suppressing the repulsive force against the screw a being screwed in. This makes it possible to prevent the watertight device 1 from rotating together when the screw a is screwed in.

[0051] In the first embodiment of the water stop device 1, the outer diameter of the packing portion 2 and the through hole 4 are coaxial, but in reality, the relationship between the shank c of the screw a inserted into the through hole 4 and the through hole 4 is eccentric to the extent that the threaded engagement surface 5 faces radially inward relative to the through hole 4, and as a result, the distance from the shank of the screw a to the side of the outer periphery of the packing portion 2 opposite the eccentric direction can be made longer than when the shank of the screw a and the through hole 4 are coaxial.This increases the friction force generated between the packing portion 2 and the exterior wall panel, which is the member to be fastened, and improves the ability to prevent the water stop device 1 from rotating together when the screw a is screwed in.

[0052] Next, Fig. 8 shows a second embodiment of the water stop device 1. Note that the same members as those in the first embodiment will be described with the same reference numerals.

[0053] The water stop device 1 of this second embodiment has a through hole 4 in the packing portion 2 that is eccentric to the center of the outer diameter of the packing portion 2, making it possible to more effectively prevent the water stop device 1 from rotating when the screw a is screwed in.The relationship between the outer diameter of the packing portion 2 and the inner diameter of the through hole 4, and between the through hole 4 and the leg portion 3 is the same as in the first embodiment.

[0054] In the second embodiment, the eccentricity of the through hole 4 relative to the outer diameter of the packing portion 2 is set on a radial center line that passes through the center of the outer diameter of the packing portion 2 and is perpendicular to the screw-engagement surface 5 of the leg portion 3 provided on the packing portion 2, in the direction opposite to the screw-engagement surface 5 across the center of the outer diameter of the packing portion 2.

[0055] In this way, when the through hole 4 is provided eccentrically with respect to the packing portion 2 under the conditions described above, the distance between the outer periphery of the packing portion 2 and the inner periphery of the through hole 4 along the eccentric direction of the through hole 4 is such that the distance α on the side opposite the eccentric direction on the side where the leg 3 is located is wider than the distance β on the eccentric side, such that α > β. As a result, the distance from the axis of the screw a inserted into the through hole 4 to the outer periphery of the packing portion 2 at the distance α can be set longer than the distance at the same point when the outer periphery of the packing portion 2 and the through hole 4 are concentric, as in the first embodiment. Therefore, when the packing portion 2 is to rotate together when the screw a is screwed in, the outer diameter of the packing portion 2 about which the packing portion 2 attempts to rotate is increased, and the area of ​​the connection between the leg 3 and the packing portion 2 where the greatest rotational force is generated is increased. This increases the frictional force between the head b of the screw a and the exterior wall material being fastened, and reliably prevents the watertight device 1 from rotating together.

[0056] The water stop device of this invention is configured as described above. For example, as shown in Figure 9, in a structure in which an exterior wall is formed by fixing a plurality of exterior wall materials 9 to the outside of a base material 8 with screws a, when the exterior wall base material 8 needs to have standing strength to build scaffolding for renovations, etc., the connector to the scaffolding is fixed with a large diameter screw 10 that is screwed into the base material 8 from the outer surface of the exterior wall material 9.

[0057] When attaching such a connector, to ensure strength, a screw with a larger diameter than the screw a that secures the exterior wall material is used, and a pilot hole that fits the large diameter screw is drilled from the exterior wall material 9 to the base material 8 in the same location as a new screw hole or the screw hole from which the screw that secured the exterior wall material was removed. The connector is attached by screwing the large diameter screw into this pilot hole, and when the work is completed and the large diameter screw is loosened and the connector is removed, a large diameter screw hole 10 remains from the exterior wall material 9 to the base material 8. If this is left as it is, rainwater will seep into the room from the exterior wall, so the large diameter screw hole 10 must be filled using water stop device 1 and screw a.

[0058] Here, when filling the large diameter screw hole 10 with the water stopper 1 and a screw, it is preferable to use the screw a that fixed the exterior wall material 9 or a screw of the same size, and to match the head size with that of the screw that fixes the exterior wall material 9, thereby improving the design appearance of the exterior wall.

[0059] For example, the base material 8 may be a structural material such as C-section steel, and the exterior wall material 9 may be based on a metal plate that is thinner than the base material 8, with gypsum board layered on top of it. To fill the large-diameter screw hole 10 formed in the base material 8 from the exterior wall material 9, the leg 3 of the water stop device 1 is inserted from the exterior wall material 9 into the large-diameter screw hole 10 in the base material 8, and the packing part 2 is placed on the outer surface of the exterior wall material 9, as shown in Figures 3 and 9, the through hole 4 of the packing part 2 overlaps with the large-diameter screw hole 10 in the exterior wall material 9, and the leg part 3 passes through the large-diameter screw hole 10, filling the inner space of the large-diameter screw hole 10 by the cross-sectional shape of the leg part 3. At the same time, the through hole 4 is offset from the large-diameter screw hole 10 by the thickness of the leg part 3, and the inner edges of the through hole 4 and the opposite screw surface 5 are aligned with each other.

[0060] In this state, the tip of the shank c of the screw a is inserted through the through hole 4 in the packing part 2 toward the large diameter screw hole 10 in the base material 8, and when the screw a is screwed in, the threads d of the shank c advance while biting into the part where the inner periphery of the through hole 4 and the inner peripheral edge of the large diameter screw hole 10 are aligned, and the threaded surface 5 of the leg part 3 located opposite this, as if pushing apart, and as the screw is screwed in, the head b of the screw a overlaps the packing part 2, and the screw is screwed in until it is in a state where it is pressed against the exterior wall material 9 and a compressive force is applied, and the large diameter screw hole 10 is filled with the small screw a of this size, providing a waterproof function to the part in question.

[0061] When screw a is screwed in as described above, leg 3 passes through large-diameter screw hole 10 in base material 8, so even if the inner diameter of large-diameter screw hole 10 is slightly deformed and enlarged, or even if there is a difference in diameter between thread d and large-diameter screw hole 10, this play can be filled by leg 3. Furthermore, thread d is screwed into large-diameter screw hole 10 and the threading surface 5 of leg 3 pressed against the inner surface of large-diameter screw hole 10, ensuring the fixing strength of screw a to base material 8, and head b of screw a tightens and fixes gasket part 2 to exterior wall material 9.

[0062] When the screw a is screwed in, the rotating head b of the screw a presses the packing part 2 against the exterior wall material 9, and as the thread d screws into the threaded surface 5 of the leg part 3, a rotational force is applied to the water-stop device 1 in the direction co-rotating with the rotation of the screw a. However, because the packing part 2 is eccentric with respect to the axis of the screw a, which is the center of rotation, the contact area of ​​the packing part 2 on the eccentric side becomes larger, and the frictional force generated in this area of ​​contact increases. This effectively prevents the packing part 2 from co-rotating when the screw a is tightened, and strengthens the pressure contact force of the packing part 2 against the exterior wall material 9. Therefore, the packing part 2 can improve the strength and water-stopping ability of the part of the exterior wall material 9 fixed by the screw a.

[0063] Furthermore, packing portion 2 is pressurized by tightening screw a when it is screwed in, and a torsional force is applied in the direction of rotation of screw a. However, since through-hole 4 provided in packing portion 2 has a diameter equal to or larger than the outer diameter of thread d and gaps 7 are secured on both sides of shank c of screw a to allow deformation of packing portion 2, the tolerance for deformation of packing portion 2 is increased, and as a result, compression in the thickness direction and co-rotational force are applied, and as shown in Figure 7, both sides of packing portion 2 after screw a is tightened are forced toward gaps 7. As the pressure moves inward, the overall shape becomes elliptical, and the packing portion 2 is not forcibly deformed and therefore does not break. As shown in Figures 3 and 4, the pressurized packing portion 2 overlaps the exterior wall material 9 so as to block the large diameter screw hole 10, and the head b of the screw a that overlaps the outer surface of this packing portion 2 has the same diameter as or a larger diameter than the packing portion 2, so the outer end of the large diameter hole 10 is securely sealed by the packing portion 2, and the portion where the screw a is screwed from the exterior wall material 9 to the base material 8 can be kept watertight.

[0064] Furthermore, by effectively preventing the packing portion 2 from rotating together with the thread a, it is possible to prevent the leg portion 3 from breaking off from the packing portion 2, and the function of the water stop device 1 can be reliably performed.

[0065] As described above, by closing the large diameter screw hole 10 from which a screw larger than the screw a used to fix the exterior wall material 9 has been removed with the screw a, the size of the screw heads in the fixing portion using the existing screw a can be made uniform, thereby improving the aesthetic appearance.

[0066] Furthermore, by setting the legs 3 longer, the water stop device 1 is not limited to use on exterior walls for fixing exterior wall materials as described above, but can be used in a wide range of applications, such as when the pilot hole or screw hole into which the screw is screwed is large in diameter in fixing parts using screws, or when the diameter of the pilot hole is larger than the screw to be screwed in. [Explanation of symbols]

[0067] 1 Water stopper 2 Packing part 3 legs 4 through holes 5 Threaded surface 5´ end face 6. Raised edge 7. Gap 8 Undercoat 9 Exterior wall materials 10 Large diameter screw holes a Screw b head c Shaft part d thread

Claims

1. A waterproofing device for screw fastening parts comprising: an annular packing part having a through hole with a diameter larger than the outer diameter of the threads formed on the shank part, for inserting the shank part of a screw to be used in combination therewith; and a leg part provided on the side of the packing part opposite the side where the screw head overlaps, so as to extend long along the axial direction of the through hole; the side of the leg part that faces the axial direction of the through hole becomes the threaded engagement surface for the threads formed on the shank part of the screw; and the end of the threaded engagement surface of the leg part that faces the packing part is arranged so as to face the radially inward side of the through hole at a position on the inner circumferential surface of the through hole; and the relationship between the threaded engagement surface and a part of the inner circumferential surface of the through hole opposite the threaded engagement surface across the axis of the through hole is set so that the distance from an imaginary axial extension line at the opposite position to the threaded engagement surface is equal to or wider than the outer diameter of the threads of the screw.

2. A watertight device for a screw-fastened portion as described in claim 1, wherein the inner diameter of the through hole of the packing portion is φD, and the distance from an imaginary axial extension line of a portion of the inner surface of the through hole that is positioned opposite the threaded surface to the threaded surface is D', and φD > D'.

3. 3. A watertight device for a screw-fastened portion according to claim 1 or 2, wherein the distance from an imaginary axial extension line of a portion of the inner surface of the through hole that is positioned opposite the threaded surface to the threaded surface is D', and the outer diameter of the thread of the screw used in combination is φd, so that D'≧φd (D'max ≒ 0.5 mm + φd).

4. 2. The waterproofing device for a screw-fastened portion according to claim 1, wherein the center of the through hole is eccentric with respect to the center of the outer periphery of the packing portion.

5. A watertight device for a screw-fastened portion as described in claim 4, wherein the eccentric direction of the through hole relative to the packing portion is set so that the center of the through hole is located on the radial center line passing through the center of the outer diameter of the packing portion at a right angle to the screw-fastening surface of the leg portion, on the opposite side of the screw-fastening surface across the center of the outer diameter of the packing portion.

6. A watertight device for a screw-fastened portion as described in claim 1, wherein when the shank of the screw is inserted into the through hole of the packing portion, gaps are formed on both sides of the shank of the screw between the inner surface of the through hole and the surface of the shank of the screw to allow deformation of the packing portion.

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