JP2022129033A - screw - Google Patents

Abstract

To provide a screw suitable for a covering method for suppressing the occurrence of come-out that a bit comes off from the screw even if a rotational load is high.SOLUTION: A screw 1A comprises a head part 3 at which a recess 2A fit with a driver bit is formed, and a shaft part 4 at which a screw thread 40 is formed. The recess 2A has six pieces of apexes 20A in a peripheral direction of the head part, the apexes 20A are constituted of curve lines which become protrusive toward an external periphery of the head part 3, and a clearance between the apexes 20A is constituted of a curve line which becomes protrusive toward a center of the head part 3, and has an inside face 21A which is parallel to an axial direction of the shaft part 4. In the screw 1A, a thickness of the head part 3 is 1.2 mm or thicker and 2.4 mm or thinner, a depth of the recess 2A is 1.6 mm or deeper, and a wall thickness of a periphery of the recess 2A is 0.7 mm or thicker.SELECTED DRAWING: Figure 1B

Description

TECHNICAL FIELD The present invention relates to screws used in roof construction and the like.

As a roof construction method, a method called a cover construction method has been proposed in which a sheet metal made of Galvalume steel plate (registered trademark) is overlaid on the slate material on a roof with a slate material attached to a base made of wood.

Conventionally, an impact driver capable of applying impact in the direction of rotation has been used in roof construction. In the cover construction method described above, when an impact driver is used, a strong pressing force is required by the operator using the impact driver because the screw is forced to penetrate the sheet metal or slate material. Also, the high rotational load due to the impact in the direction of rotation tends to cause cam-out in which the bit comes off the screw, and a stronger pressing force is required to prevent cam-out.

Therefore, in order to reduce the pressing force, as described in Patent Document 1, etc., a screw driving machine equipped with a striking mechanism and a screw tightening mechanism that tightens by rotating after driving the screw in the axial direction is used as a cover construction method. It is conceivable to apply

Japanese Unexamined Patent Application Publication No. 2010-23169

By using the above-mentioned screw driving machine for the cover construction method, the screw is driven through the sheet metal or slate material by air pressure, so the pressing force of the worker using the screw driving machine when the screw is driven through can be reduced.

On the other hand, one of the characteristics of the cross bit, which is commonly used for screws, is that when the rotational load is high, the bit tends to come out of the screw. However, in the screw driving machine described above, since the bit is pressed against the screw by air pressure during screwing, and the screw is pressed against the object to be fastened via the bit, even if the pressing force by the operator using the screw driving machine is increased, It is difficult to prevent the occurrence of cam-out due to the characteristics of the cross recess.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a screw suitable for a cover construction method that suppresses the occurrence of cam-out in which the bit comes off the screw even when the rotational load is high. .

In order to solve the above-described problems, the present invention provides a head portion formed with a recess for fitting a driver bit, and a shaft portion formed with a screw thread. Between the surface and the shank, an enlarged diameter portion having a diameter larger than that of the shank is provided, and the recess has at least three apexes along the circumferential direction of the head that rotates about the shank. The screw is composed of a straight line or a combination of straight and curved lines or a curved line that is concave toward the center of the head.

In the present invention, there are at least three apexes along the circumferential direction of the head that rotates about the shaft, and the space between the apexes is a straight line or a combination of straight lines and curves that are concave toward the center of the head. Alternatively, a bit with a shape that matches the curved recess is used to tighten the screw.

ADVANTAGE OF THE INVENTION According to this invention, generation|occurrence|production of the cam-out which a bit separates from a screw can be suppressed, and high torque can be reliably transmitted between a bit and a screw. Further, by providing an enlarged diameter portion having a larger diameter than the shaft portion between the bearing surface formed on the head portion and the shaft portion, the strength of the screw can be ensured.

FIG. 2 is a cross-sectional view of a main part showing an example of a screw according to the present embodiment; FIG. 2 is a cross-sectional view of a main part showing an example of a screw according to the present embodiment; FIG. 4 is a cross-sectional view of a main part showing another example of the screw according to the embodiment; FIG. 4 is a cross-sectional view of a main part showing another example of the screw according to the embodiment; FIG. 5 is a cross-sectional view of a main part showing a modification of the screw according to the embodiment; FIG. 5 is a cross-sectional view of a main part showing a modification of the screw according to the embodiment; FIG. 6 is a cross-sectional view of a main part showing another modification of the screw of the embodiment; FIG. 4 is a side view showing an example of a screw according to this embodiment; It is a front view which shows an example of the screw|crew of this Embodiment. It is a perspective view which shows an example of the screw|crew of this Embodiment. FIG. 2B is a cross-sectional view taken along the line AA of FIG. 2B showing the screw of one example of the present embodiment; FIG. 2B is a cross-sectional view along the line BB of FIG. 2B showing the screw of one example of the present embodiment; FIG. 4 is a side view showing another example of the screw of the embodiment; FIG. 2C is a cross-sectional view taken along the line AA of FIG. 2B showing another example screw of the present embodiment; FIG. 2B is a cross-sectional view along the line BB of FIG. 2B showing another example screw of the present embodiment; It is a perspective view which shows an example of the provision form of the screw|crew of this Embodiment. It is a sectional view showing the type of use of the screw of an example of this embodiment. FIG. 11 is a cross-sectional view showing a usage pattern of a screw in another example of the present embodiment; FIG. 4 is a side view showing an example of a driver bit; FIG. 4 is a front view showing an example of a driver bit; 1 is a perspective view showing an example of a driver bit; 4B is an enlarged view of part C in FIG. 4A showing an example of a driver bit; FIG. FIG. 4 is a cross-sectional view showing a fitting state of a screw and a driver bit; FIG. 4 is a cross-sectional view showing a fitting state of a screw and a driver bit; FIG. 11 is a cross-sectional view of a main part showing still another modified example of the screw according to the present embodiment; FIG. 11 is a cross-sectional view of a main part showing still another modified example of the screw according to the present embodiment; FIG. 11 is a cross-sectional view of a main part showing still another modified example of the screw according to the present embodiment; FIG. 11 is a cross-sectional view of a main part showing still another modified example of the screw according to the present embodiment; FIG. 11 is a cross-sectional view of a main part showing still another modified example of the screw according to the present embodiment; FIG. 11 is a cross-sectional view of a main part showing still another modified example of the screw according to the present embodiment; FIG. 11 is a cross-sectional view of a main part showing still another modified example of the screw according to the present embodiment; FIG. 11 is a cross-sectional view of a main part showing still another modified example of the screw according to the present embodiment; FIG. 11 is a cross-sectional view of a main part showing still another modified example of the screw according to the present embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a screw according to the present invention will be described below with reference to the drawings.

<Configuration example of screw according to the present embodiment>
1A and 1B are cross-sectional views of essential parts showing an example of the screw of this embodiment, and FIG. 1B shows the dimensional relationship of the screw shown in FIG. 1A. 1C and 1D are cross-sectional views of essential parts showing another example of the screw of the present embodiment, and FIG. 1D shows the dimensional relationship of the screw shown in FIG. 1C. Furthermore, FIGS. 1E and 1F are cross-sectional views of essential parts showing modifications of the screw according to the present embodiment, and FIG. 1G is a cross-sectional view of essential parts showing another modification of the screw according to the embodiment. Moreover, FIG. 2A is a side view showing an example of the screw of the present embodiment, FIG. 2B is a front view showing an example of the screw of the present embodiment, and FIG. 2C is a perspective view showing an example of the screw of the present embodiment. It is a diagram. Furthermore, FIG. 2D is a cross-sectional view taken along the line AA of FIG. 2B showing the screw of the example of the present embodiment shown in FIG. 2A, and FIG. 2E is the screw of the example of the present embodiment shown in FIG. 2A. is a cross-sectional view taken along the line BB. 2F is a side view showing another example of the screw of the present embodiment; FIG. 2G is a cross-sectional view taken along the line AA of FIG. 2B showing the screw of the other example of the present embodiment shown in FIG. 2F; FIG. 2H is a cross-sectional view taken along the line BB of FIG. 2B showing another example screw of the present embodiment shown in FIG. 2F. Moreover, FIG. 2I is a perspective view showing an example of the form of provision of the screw according to the present embodiment. Furthermore, FIG. 3A is a cross-sectional view showing a usage pattern of the screw in the example of the present embodiment shown in FIG. 1A, and FIG. 3B is a cross-sectional view showing a usage pattern of the screw in another example of the present embodiment shown in FIG. 1C. It is a diagram.

Furthermore, FIG. 4A is a side view showing an example of a driver bit used for the screws of the present embodiment shown in FIGS. 1A, 1B, 1C, 1D, 1E, and 1F, and FIG. FIG. 4C is a perspective view showing an example of a driver bit, and FIG. 4D is an enlarged view of part C in FIG. 4A showing an example of a driver bit. 5A and 5B are cross-sectional views showing the fitting state of the screw and the driver bit.

As shown in FIGS. 3A and 3B, the screw 1A is used in a roof in which a slate material 102 (or a roof material called a cement board may be used) as a first plate material is attached to a substrate 101 made of wood. It is used in a roof construction method called a cover construction method in which a sheet metal 104 made of Galvalume steel plate (registered trademark), which is a second plate material, is overlaid on 102 with a waterproof sheet 103 interposed therebetween.

Conventionally, an impact driver capable of applying impact in the direction of rotation has been used in roof construction. In the above-described cover construction method, when an impact driver is used, a strong pressing force is required to penetrate the sheet metal 104 and the slate material 102 and fasten the screw 1A to the base 101 .

Therefore, as described in Japanese Patent Application Laid-Open No. 2010-23169, a screw driving machine having a striking mechanism and a screw tightening mechanism for fastening the screw 1A in the axial direction after driving the screw 1A in the axial direction is used to drive the screw 1A. conclude. By using a screw driving machine, the load for penetrating the screw 1A through the sheet metal 104 and the slate material 102 can be reduced.

On the other hand, one of the characteristics of the cross bit, which is commonly used for screws, is that when the rotational load is high, the bit tends to come out of the screw. As described above, in a screw driving machine, the air pressure presses the bit against the screw when screwing in, and the bit presses the screw against the object to be fastened. , it is difficult to prevent the occurrence of cam-out due to the characteristics of the cross recess. Therefore, the screw 1A has a recessed shape that does not generate a force in the direction in which the screw and the bit separate even if the rotational load increases. It is configured so that it can be concluded with

Details of the screw 1A will be described below. The screw 1A has a head portion 3 formed with a recess 2A into which a driver bit provided in a screw driving machine is fitted, and a shaft portion 4 formed with a screw thread 40 on the outer circumferential surface.

Further, the screw 1A is provided with an enlarged diameter portion 5 having a larger diameter than the shaft portion 4 between the head portion 3 and the shaft portion 4 in order to secure the wall thickness around the side portion and the bottom portion of the recess 2A. As shown in FIG. 2I, a screw 1A used in a screw driving machine has a plurality of screws 1A connected by a connecting member 10A in a direction orthogonal to the axial direction of the shaft portion 4 and extending from the inner peripheral side to the outer peripheral side. Supplied in spiral wound form.

The recess 2</b>A is formed by a recess formed by opening the top surface 30 of the head 3 so as to match the shape of the bit 200 of the driver bit 201 . The recess 2A, which is called a hexalobular shape, has six apexes 20A along the circumferential direction of the head 3 that rotates about the shaft 4. Consists of curved lines that form a concave shape. Each apex 20</b>A is configured with a curved line that becomes convex toward the outer circumference of the head 3 .

Moreover, the recess 2A has an inner side surface 21A parallel to the axial direction in which the shaft portion 4 extends. Further, the recess 2A shown in FIGS. 1A, 1B, 1C, 1D, 1E and 1F comprises a guide recess 22A for guiding the bit 200 of the driver bit 201 shown in FIGS. 4A-4D. In the examples shown in FIGS. 1A, 1B, 1C, and 1D, the guide recess 22A is formed in accordance with the shape of a cone-shaped protrusion 202 having a concavely curved peripheral surface protruding from the tip of the bit 200 of the driver bit 201. , the side surface is curved inwardly so that the diameter decreases toward the bottom of the guide recess 22A. In addition, in the example shown in FIG. 1E, the guide recess 22A is configured with a linear slope on the side surface so that the diameter decreases toward the bottom of the guide recess 22A. Further, the guide recess 22A has a cylindrical shape in which the protrusion 202 of the driver bit 201 can be accommodated, in the example shown in FIG. 1F.

In the screw driving machine disclosed in Japanese Unexamined Patent Application Publication No. 2010-23169, etc., the screw 1A is supplied in a connected form, and the bit is driven in the step of axially driving the screw 1A by the driver bit 201 or in the step of rotating the driver bit 201. 200 must fit into recess 2A. Therefore, the guide recess 22A of the recess 2A guides the protrusion 202 protruding to the tip of the bit 200 of the driver bit 201, as shown in FIGS. can be fitted into the recess 2A. 1A, 1B, 1C, 1E, and 1F, the guide recess 22A has a shape that decreases in diameter toward the bottom of the guide recess 22A, for example, FIGS. 1A, 1B, and 1C. As shown in FIG. 1D, the side surface is curved in accordance with the shape of the protrusion 202 of the driver bit 201 shown in FIG. 4D, or as shown in FIG. As a result, the bit 200 of the driver bit 201 and the recess 2A of the screw 1A are engaged with each other so that the centers of the bit 200 and the recess 20A in the radial direction are guided in the mutually matching direction. Thereby, as shown in FIG. 5B, the bit of the driver bit 201 can be reliably fitted into the recess 2A of the screw 1A. Note that the recess 2A shown in FIG. 1G does not have a guide recess. In this case, the driver bit used has a configuration in which no protrusion is provided at the tip of the bit.

Now, the performance required of the screws used in the cover construction method using the sheet metal described above is to securely fix the sheet metal 104 . and the head of the screw does not sink into the sheet metal 104. - 特許庁In order to securely fix the metal plate 104, the diameter D1 of the shaft portion 4 of the screw 1A is set to 2.2. It is preferably 7 mm or more and 3.3 mm or less. That is, in order to secure strength against cutting of the shaft portion 4, the lower limit value of the diameter D1 of the shaft portion 4 of the screw 1A is preferably 2.7 mm or more. On the other hand, if the diameter of the shaft portion 4 becomes large, the driving load and the rotational load during screwing will increase, and the workability will deteriorate. preferable. In addition, in order to prevent the shaft portion 4 of the fastened screw 1A from slipping out of the base 101, the outer diameter D2 of the screw thread 40 is preferably 4.0 mm or more. Taking this into account, it is preferably 4.5 mm or less.

Further, the diameter D3 of the head portion 3 is preferably 8.1 mm or more so that the sheet metal 104 can be held by the head portion 3 so as not to come off. On the other hand, the diameter of the head 3 of the screw 1A should be smaller than the inner diameter of the nose through which the screw passes in the screw driving machine. Furthermore, in order to suppress the angle at which the screw 1A is inclined within the nose, it is preferable that the difference between the diameter D2 of the screw thread 40 of the shaft portion 4 of the screw 1A and the diameter D3 of the head portion 3 is not too large. Therefore, when the screw 1A has an outer diameter D2 of the screw thread 40 of about 4.0 mm, the upper limit of the diameter D3 of the head 3 is preferably 8.7 mm or less.

In the case where the recess 2A has a shape called hexalobular, a driver bit whose size (nominal) is called T20 or T25 is used for the screw 1A in which the outer diameter D2 of the thread 40 is about 4.0 mm. The recess 2A corresponding to the driver bit of size T20 is located on a diagonal line passing through the center of the head 3. The distance A1 between the top portions 20A is 3.84 mm. The distance A1 between the tops 20A located is 4.40 mm.

Also, as shown in FIGS. 1A, 1B, 1C, 1D, 1E, and 1F, in the configuration in which the recess 2A includes the guide recess 22A, the recess 2A corresponding to the driver bit of size T20 has a guide recess 22A. Diameter A2 of 22A is less than or equal to 2.85 mm, and in recess 2A corresponding to a driver bit of size T25, diameter A2 of guide recess 22A is less than or equal to 3.3 mm.

In the cover construction method described above, the next sheet metal 104 is superimposed on the sheet metal 104 fixed with the screws 1A. For this reason, the top of the head 3 of the screw 1A exposed on the surface of the metal plate 104 fixed to the lower side is covered with the next metal plate 104 .

The head portion 3 includes a convex portion 33 that protrudes along the axial direction of the shaft portion 4 in the opposite direction to the side on which the enlarged diameter portion 5 is provided. Therefore, the thickness T1 of the head 3 of the screw 1A is preferably 1.2 mm or more and 2.4 mm or less. If the thickness T1 of the head 3 is 2.4 mm or less, even if force is applied to the sheet metal 104 superimposed on the head 3 of the screw 1A, the sheet metal 104 will not be deformed by being pressed against the head 3 of the screw 1A. Deformation is suppressed.

The head 3 is provided with a seat surface 31 on the outer circumference of the enlarged diameter portion 5 for contacting and holding the sheet metal 104 fixed to the base 101 via the slate material 102 . Here, when the sheet metal 104 is fixed by tightening the screw 1A, the bearing surface 31, which is the surface facing the sheet metal 104 in the head portion 3, may be configured as a flat surface or as a form called a countersunk screw. , a tapered surface having a slope or a curved surface whose diameter increases from the shaft portion 4 toward the outer periphery of the head portion 3 can be considered. When the bearing surface 31 is a flat surface, the screw 1A is screwed until the entire surface of the bearing surface 31 including the outer circumference of the head portion 3 is in contact with the surface of the sheet metal 104. It becomes a state where it does not float from the surface of On the other hand, when the bearing surface 31 is formed of a tapered surface whose diameter increases from the shaft portion 4 toward the outer circumference of the head portion 3, the shaft portion 4 is tapered from the outer circumference of the head portion 3 toward the shaft portion 4. Since the screw 1A protrudes along the axial direction, the screw 1A is screwed until the outer periphery of the head portion 3 contacts the surface of the metal plate 104 while part of the seat surface 31 crushes the metal plate 104. The head 3 will not be lifted from the surface of the sheet metal 104 . Therefore, the state in which the head 3 of the screw 1A is not lifted from the surface of the metal plate 104 is the state in which the outer periphery of the bearing surface 31, which is the outer periphery of the head 3, is in contact with the surface of the metal plate 104. FIG.

Therefore, the outer periphery of the seat surface 31 is called a seat surface reference surface 32 . In the configuration in which the head portion 3 includes the convex portion 33 , the thickness T1 of the head portion 3 is the length along the axial direction of the shaft portion 4 from the top surface 30 of the head portion 3 to the seat reference surface 32 . note that. When the seat surface 31 is flat, the thickness T1 of the head portion 3 is the length along the axial direction of the shaft portion 4 from the top surface 30 of the head portion 3 to the seat surface 31 .

In the case of a screw 1A corresponding to a driver bit whose recess 2A has a size of T20, the thickness T1 of the head 3 is preferably 1.2 mm or more and 2.3 mm or less. More preferably, the upper limit is 2.0 mm or less. In the case of a screw 1A corresponding to a driver bit whose recess 2A has a size of T25, the thickness T1 of the head 3 is preferably 1.6 mm or more and 2.3 mm or less. More preferably, the upper limit is 2.0 mm or less.

Further, in order to secure an area where the driver bit and the inner side surface 21A of the recess 2A contact each other, the depth Dep1 of the recess 2A is preferably 1.6 mm or more. If the depth Dep1 of the recess 2A is 1.6 mm or more, the driver bit is prevented from coming out of the recess 2A when tightening the screw 1A with the driver bit. can be added to screw 1A.

1A, 1B, 1C, 1D, 1E, and 1F, in the configuration in which the recess 2A includes the guide recess 22A, the depth Dep2 of the guide recess 22A is 1.2 mm or more. It is preferably 1 mm or less. In the case of a screw 1A corresponding to a driver bit having a size of the recess 2A of T20, the depth Dep2 of the guide recess 22A is preferably 1.2 mm or more and 2.1 mm or less. Moreover, in the case of the screw 1A corresponding to the driver bit whose size of the recess 2A is T25, the depth Dep2 of the guide recess 22A is preferably 1.5 mm or more and 2.1 mm or less.

As described above, the recess 2A corresponding to the driver bit of size T25 has a diameter of an outer circumference passing through each apex 20A, in this example, a distance A between the apexes 20A located on a diagonal line is 4.4 mm, and the recess 2A is larger than the diameter D1 of the shaft portion 4 . On the other hand, the thickness T1 of the head 3 of the screw 1A is preferably 2.0 mm or less, while the depth Dep1 of the recess 2A is preferably 1.6 mm or more.

The wall thickness around the sides and bottom of the recess 2A is preferably 0.7 mm or more. On the other hand, in the above dimensional relationship, if the bearing surface 31 is a flat surface and the shaft portion 4 is a screw that is connected to the bearing surface 31 with substantially the same diameter without the enlarged diameter portion 5, the recess 2A is formed. The thickness between the bottom portion and the bearing surface 31 of the head portion 3 can only be secured at a maximum of 0.4 mm, which does not satisfy the value defined by the present invention. Therefore, with a screw having a shape in which the shaft portion 4 is connected to the bearing surface 31 with substantially the same diameter without the enlarged diameter portion 5, the necessary thickness cannot be secured around the side and bottom portions of the recess 2A.

Therefore, the screw 1A is provided with an enlarged diameter portion 5 having a larger diameter than the shaft portion 4 between the head portion 3 and the shaft portion 4 in order to secure the wall thickness around the side portion and the bottom portion of the recess 2A. By providing the enlarged diameter portion 5 between the head portion 3 and the shaft portion 4, the depth Dep1 of the recess 2A can be made equal to or greater than the thickness T1 of the head portion 3 of the screw 1A.

In this case, if the recess 2A is in the form called hexalobular and, as shown in FIGS. The thickness T2 between the recess 2A and the enlarged diameter portion 5 is equal to the thickness between the top portion 20A of the recess 2A and the enlarged diameter portion 5 and the thickness between the guiding recess 22A of the recess 2A and the enlarged diameter portion 5. Any of the thicknesses will be the thinnest. Further, as shown in FIG. 1D, if the recess 2A does not have a guide concave portion, the thickness T2 between the recess 2A and the enlarged diameter portion 5 is The wall thickness between is the thinnest. The thickness T2 between the recess 2A and the enlarged diameter portion 5 is preferably 0.7 mm or more at the thinnest portion.

Now, in the screw 1A having the enlarged diameter portion 5 between the head portion 3 and the shank portion 4, the diameter of the enlarged diameter portion 5 increases from the starting point 51 of the enlarged diameter portion 5 with respect to the shank portion 4. If the length along the axial direction of the shaft portion 4 to the seat surface reference surface 32 (seat surface 31) is the total thickness of the sheet metal 104 and the waterproof sheet 103, which is 1.35 mm or less in this example, the head Even if the screw 1A is screwed until the seat surface reference surface 32 (seat surface 31) of the portion 3 is in close contact with the metal plate 104, the enlarged diameter portion 5 does not reach the slate member 102.

However, in this case, if the enlarged diameter portion 5 is configured with a tapered surface that increases in diameter from the starting point 51 of the enlarged diameter portion 5 toward the seating surface reference surface 32, the gap between the recess 2A and the enlarged diameter portion 5 will increase. The thickness T2 is less than 0.7 mm at the thinnest portion.

On the other hand, the length along the axial direction of the shaft portion 4 from the starting point 51 of the enlarged diameter portion 5 to the seat surface reference surface 32 (seat surface 31) of the head portion 3 is the thickness of the sheet metal 104 and the waterproof sheet 103. Consider a configuration that exceeds the sum of

In this case, the enlarged diameter portion 5 reaches the slate material 102 . However, the hole in the portion of the slate material 102 through which the screw thread 40 passes in the fastening operation of the screw 1A has a portion inside the outer diameter D2 of the screw thread 40 on the opening side facing the waterproof sheet 103. The slate material 102 is destroyed during penetration. Therefore, in the vicinity of the side of the slate member 102 facing the waterproof sheet 103 , even a portion of the enlarged diameter portion 5 that is thicker than the diameter D1 of the shaft portion 4 can penetrate the slate member 102 .

Therefore, in the enlarged diameter portion 5, from the position P1, which is a portion having the same diameter as the outer diameter D2 of the thread 40, to the bearing surface reference surface 32 (seating surface 31) of the head portion 3, in the axial direction of the shaft portion 4 The length L1 along the length is preferably about the same as the total thickness of the sheet metal 104 and the waterproof sheet 103, preferably 1.2 mm or more, and in this example, about 1.35 mm to 1.65 mm. be. In this example, since the outer diameter D2 of the screw thread 40 is 4.2 mm, the enlarged diameter portion 5 extends from the bearing surface reference surface 32 (bearing surface 31) of the head portion 3 along the axial direction of the shaft portion 4. It is preferable that the diameter at a position P1 spaced apart by 0.2 mm or more is 4.2 mm or less.

Further, in order to make the thickness T2 between the recess 2A and the enlarged diameter portion 5 to be 0.7 mm or more at the thinnest portion, from the starting point 51 of the enlarged diameter portion 5, The length L2 to 32 (seat surface 31) is preferably 1.5 mm or more and 3.5 mm or less.

The length L2 from the starting point 51 of the enlarged diameter portion 5 to the bearing surface reference surface 32 (the bearing surface 31) of the head portion 3 is 1.7 mm or more and 2.6 mm when the recess 2A is configured to include the guide recess 22A. The following are preferable. In the case of a screw 1A corresponding to a driver bit whose size of the recess 2A is T20, the length L2 from the starting point 51 of the enlarged diameter portion 5 to the bearing surface reference surface 32 (bearing surface 31) of the head 3 is 1. 0.7 mm or more and 2.6 mm or less. Further, in the case of a screw 1A corresponding to a driver bit whose size of the recess 2A is T20, the length L2 from the starting point 51 of the enlarged diameter portion 5 to the bearing surface reference surface 32 (bearing surface 31) of the head 3 is 1 0.7 mm or more and 2.6 mm or less.

The length L2 from the starting point 51 of the enlarged diameter portion 5 to the bearing surface reference surface 32 (the bearing surface 31) of the head portion 3 is 1.5 mm or more when the recess 2A is configured without the guide recess 22A. It is preferably 5 mm or less. In the case of a screw 1A corresponding to a driver bit whose size of the recess 2A is T20, the length L2 from the starting point 51 of the enlarged diameter portion 5 to the bearing surface reference surface 32 (bearing surface 31) of the head 3 is 1. .7 mm or more and 3.5 mm or less. Further, in the case of a screw 1A corresponding to a driver bit whose size of the recess 2A is T20, the length L2 from the starting point 51 of the enlarged diameter portion 5 to the bearing surface reference surface 32 (bearing surface 31) of the head 3 is 1 0.7 mm or more and 2.9 mm or less.

Further, in the enlarged diameter portion 5 , the portion from the position P1 where the diameter is the same as the outer diameter D2 of the screw thread 40 to the bearing surface reference surface 32 (the bearing surface 31 ) of the head portion 3 is in contact with the sheet metal 104 . In order to keep the head 3 of the screw 1A from floating above the surface of the metal plate 104, the bearing surface reference surface 32, which is the outer circumference of the head 3, needs to be in contact with the surface of the metal plate 104. Therefore, in order to deform the sheet metal 104 and the waterproof sheet 103, the bearing surface reference surface 32 (the bearing surface 31) of the head 3 is moved from the position P1 where the diameter is the same as the outer diameter D2 of the thread 40 in the enlarged diameter portion 5. A tapered surface 50 whose diameter increases from the shaft portion 4 toward the head portion 3 is provided between.

The angle α formed by the tapered surface 50 is preferably 70° or more and 115° or less when the recess 2A includes the guide recess 22A and the diameter D3 of the head 3 is 8.4 mm. In the case of a screw 1A corresponding to a driver bit whose size of the recess 2A is T20, the angle α formed by the tapered surface 50 is preferably 76° or more and 115° or less. Further, in the case of the screw 1A corresponding to the driver bit having the size of the recess 2A of T25, the angle α formed by the tapered surface 50 is preferably 70° or more and 115° or less.

The angle α formed by the tapered surface 50 is preferably 38° or more and 115° or less when the recess 2A is configured without the guide recess 22A and the diameter D3 of the head 3 is 8.4 mm. In the case of a screw 1A corresponding to a driver bit having a size of the recess 2A of T20, the angle α formed by the tapered surface 50 is preferably 38° or more and 115° or less. Moreover, in the case of the screw 1A corresponding to the driver bit having the size of the recess 2A of T25, the angle α formed by the tapered surface 50 is preferably 57° or more and 115° or less.

When the angle α formed by the tapered surface 50 is the above value, the thickness T2 between the recess 2A and the enlarged diameter portion 5 is set to 0.7 mm or more at the thinnest portion, and the depth Dep1 of the recess 2A is set to 1. .6 mm or more. Further, by providing the enlarged diameter portion 5, the thickness T1 of the head 3 of the screw 1A is 1.2 mm or more and 2.4 mm or less, and the depth Dep1 of the recess 2A is set to thickness T1 or more.

Therefore, the depth Dep1 of the recess 2A is preferably 1.6 mm or more and 2.5 mm or less. In the case of the screw 1A corresponding to a driver bit having a size of the recess 2A of T20, the depth Dep1 of the recess 2A is preferably 1.6 mm or more and 2.5 mm or less. Moreover, in the case of the screw 1A corresponding to the driver bit whose size of the recess 2A is T25, the depth Dep1 of the recess 2A is preferably 1.6 mm or more and 2.0 mm or less.

On the other hand, if the angle α formed by the tapered surface 50 exceeds the above value, the area of the bearing surface 31 may become small, or the flat surface forming the bearing surface 31 may not be formed. In order to secure the area of the seat surface 31 without increasing the outer diameter of the head 3 above the above value, a lower seat surface connecting surface 50a is provided between the tapered surface 50 and the seat surface 31, and the tapered surface 50 and the seat surface 50a are provided. Instead of directly connecting the surfaces 31, a so-called stepped shape may be used. The angle β (half angle) formed by the lower seat surface connecting surface 50a is preferably 0° or more and 35° or less. Alternatively, as shown in FIGS. 1C and 1D, it may be configured with a straight surface along the axial direction of the shaft portion 4 . In addition, the length L3 of the lower seating surface connecting surface 50a along the axial direction of the shaft portion 4, that is, the distance between the lower seating surface connecting surface 50a and the tapered surface 50 from the seating surface reference surface 32 (seat surface 31) of the head 3. The length to the connecting point P2 with is preferably 0.3 mm or more and 1.3 mm or less. Furthermore, as shown in FIGS. 1A and 1B, between the tapered surface 50 configured by the linear slope and the starting point 51 of the enlarged diameter portion 5, in this example, from the position P1 to the starting point 51 of the enlarged diameter portion 5 A curved surface 50 b that is concave toward the center of the shaft portion 4 may be used to form the space between. By forming the curved surface 50b that is concave toward the center of the shaft portion 4 from the position P1 to the starting point 51 of the enlarged diameter portion 5, an increase in the load when tightening the screw 1A is suppressed, and the enlarged diameter portion 5 is expanded. The length L2 from the starting point 51 of the diameter portion 5 to the bearing surface reference surface 32 (the bearing surface 31) of the head portion 3 can be extended within a specified range, and the distance between the recess 2A and the enlarged diameter portion 5 is The thickness T2 can be secured and the depth Dep1 of the recess 2A can be increased.

6A to 6I are cross-sectional views of essential parts showing still other modifications of the screw according to the present embodiment. In the enlarged diameter portion 5, if the diameter is smaller than the outer diameter D2 of the screw thread 40, the distance between the position P1 where the diameter is the same as the outer diameter D2 of the screw thread 40 and the starting point 51 of the enlarged diameter portion 5 is a slate. The material 102 is penetrable. Therefore, the enlarged diameter portion 5 has a diameter equal to the outer diameter D2 of the screw thread 40 from the starting point 51 to the starting point 51 of the enlarged diameter portion 5 from the position P1 where the diameter is the same as the outer diameter D2 of the screw thread 40. It is also possible to provide a tapered surface whose diameter increases toward the position P1. A tapered surface 52a provided in the enlarged diameter portion 5 from the position P1 where the diameter is the same as the outer diameter D2 of the screw thread 40 to the starting point 51 of the enlarged diameter portion 5 may have the same angle as the tapered surface 50. As shown in 6A, the angle α1 (half angle) formed by the tapered surface 50 and the angle α2 (half angle) formed by the tapered surface 52a provided between the position P1 and the starting point 51 of the enlarged diameter portion 5 may be different angles. At this time, the position where the tapered surface 50 and the tapered surface 52 are connected does not have to coincide with the position P1 where the diameter is the same as the outer diameter D2 of the thread 40 . An imaginary circle C1 centered on the recess 2A side and having a radius equal to the minimum value (0.7 mm in this example) obtained as the thickness T2 between the recess 2A and the enlarged diameter portion 5 is indicated by a two-dot chain line. If the angle formed by each tapered surface is a value such that each tapered surface does not enter the virtual circle C1 centered at an arbitrary point O on the side of the recess 2A, the recess 2A and each taper The wall thickness T2 between the surfaces becomes a desired value or more.

Further, as shown in FIG. 6B, the shaft portion 4 is arranged such that the portion from the position P1 to the starting point 51 of the enlarged diameter portion 5 does not enter the virtual circle C1 centered at an arbitrary point O on the side of the recess 2A. A curved surface 52b that is convex toward the center may be used. Furthermore, as shown in FIG. 6C , the enlarged diameter portion 5 is located between the position P1 where the diameter is the same as the outer diameter D2 of the screw thread 40 and the bearing surface reference surface 32 (the bearing surface 31) of the head portion 3. A tapered surface 50 is provided on the side close to the shaft portion 4 so that the diameter increases from the shaft portion 4 toward the head portion 3 and does not enter the virtual circle C1 centered at an arbitrary point O on the side of the recess 2A. Alternatively, a straight surface 53a along the axial direction of the shaft portion 4 may be provided on the side near the seat surface 31 so as not to enter the virtual circle C1 centered at an arbitrary point O on the side of the recess 2A. good. Further, the enlarged diameter portion 5 extends from the position P1 where the diameter is the same as the outer diameter D2 of the screw thread 40 to the starting point 51 of the enlarged diameter portion 5. A step portion having a larger diameter may be provided toward the position P1. Further, as shown in FIG. 6D, the enlarged diameter portion 5 is located at a position where the diameter is the same as the outer diameter D2 of the thread 40 so that the thickness T2 between the recess 2A and the enlarged diameter portion 5 is substantially uniform. A stepped portion 53b that follows the shape of the recess 2A may be provided between P1 and the seat surface reference surface 32 (seat surface 31) of the head 3.

Further, as shown in FIG. 6E, the enlarged diameter portion 5 extends from the bearing surface 31 of the head portion 3 to the position P1 where the diameter is the same as the outer diameter D2 of the thread 40, and from the position P1 to the enlarged diameter portion 5. is composed of a single diameter arc C2 or a combination of a plurality of different diameter arcs, and does not enter the virtual circle C1 centered at an arbitrary point O on the side of the recess 2A 54a may be provided. Further, as shown in FIG. 6F , the enlarged diameter portion 5 has a seat surface 31 formed of a tapered surface that is a slope or curved surface that increases in diameter from the shaft portion 4 toward the outer periphery of the head portion 3 . From the bearing surface reference surface 32 to the position P1 where the diameter is the same as the outer diameter D2 of the screw thread 40, and from the position P1 to the starting point 51 of the enlarged diameter portion 5, there is a single diameter arc C2, Alternatively, the curved surface 54b may be configured by combining a plurality of circular arcs with different diameters and not entering the virtual circle C1 centered at an arbitrary point O on the side of the recess 2A.

Further, as shown in FIG. 6G, in the screw 1A, in the enlarged diameter portion 5, the tapered surface 50 facing the guide concave portion 22A of the recess 2A is inside a virtual circle C1 centered at an arbitrary point O on the recess 2A side. If it is possible to prevent it from entering, it may be configured to have a head 3 in a form called a button head. Further, as shown in FIG. 6H , in the expanded diameter portion 5 , the tapered surface 50 extends to the outer circumference of the head portion 3 , and the bearing surface 31 has a diameter that increases from the shaft portion 4 toward the outer circumference of the head portion 3 . Even when it is configured with a tapered surface that increases in size, it may be configured to include the head 3 in a form called a button head.

Further, as shown in FIG. 6I, when the head 3 does not have the convex portion 33 and the screw 1A is in the form of a countersunk screw, the bearing surface 31 is formed by a part of the tapered surface 50, but the recess 2A is formed. The depth Dep1 is 1.6 mm or more, and the tapered surface 50 facing the recess 2A and the guide recess 22A does not enter the imaginary circle C1 centered at an arbitrary point O on the recess 2A side, and the taper If the screw 1A can be screwed until a portion of the surface 50 crushes the sheet metal 104 and the outer periphery of the head 3 (the seating surface reference surface 32) contacts the surface of the sheet metal 104, it may be in the form of a countersunk screw.

As described above, in the screw 1A, the recess 2A into which the driver bit is fitted has at least three apexes 20A along the circumferential direction of the head 3 that rotates around the shaft 4. The space is composed of a straight line or a combination of a straight line and a curved line concave toward the center of the head 3 or a curved line, and the diameter between the bearing surface 31 of the head 3 and the shaft 4 is larger than that of the shaft 4. By providing the enlarged diameter portion 5, it is possible to obtain the effect of suppressing the occurrence of cam-out while ensuring the strength of the screw 1A.

It is preferable that the dimensions of each part of the screw 1A satisfy the values defined in the present invention described above. That is, the diameter D3 of the head 3 is 8.1 mm or more and 8.7 mm or less, the thickness T1 of the head 4 is 1.2 mm or more and 2.4 mm or less, and the depth Dep1 of the recess 20A is 1.6 mm or more. The diameter D1 of the shaft portion 4 is 2.7 mm or more and 3.3 mm or less, the diameter D2 of the thread 40 of the shaft portion 4 is 4.1 mm or more and 4.35 mm or less, and the recess 2A and the enlarged diameter portion 5 The thickness T2 between the The length L2 along the axial direction of 4 is 1.5 mm or more and 3.1 mm or less.

Also, the angle α formed by the tapered surface 50 is 38° or more and 115° or less, and when the guide recess 22A is provided, the angle α formed by the tapered surface 50 is 70° or more and 115° or less.

Further, the enlarged diameter portion 5 has a diameter of 4.2 mm or less at a position P1 that is 1.2 mm or more away from the bearing surface 31 (seating surface reference surface 32) of the head portion 3 along the axial direction of the shaft portion 4. .

The dimensions of each portion of the screw 1A satisfy the values defined in the present invention, so that the head 3 of the screw 1A is not lifted from the metal plate 104 when fixing the metal plate 104 in the cover construction method described above. Moreover, the head 3 of the screw 1A does not sink into the metal plate 104.

As a result, in the cover construction method, the screw 1A can be applied to the sheet metal 104 and the slate material 102 by using a screw driving machine equipped with an impact mechanism and a screw tightening mechanism that fasten the screw 1A in the axial direction and then rotate it. It is possible to reduce the load for penetrating the Moreover, even if the rotational load is high, it is possible to suppress the occurrence of cam-out in which the bit 200 comes off the screw 1A.

In addition, in the screw 1A, the recess 2A is not limited to the form called hexalobular, and is a quadrangle having four apexes 20A along the circumferential direction of the head 3 and straight lines between the apexes 20A. Each side of the quadrangle has an inner side surface 21A parallel to the axial direction of the shaft portion 4, and has six apex portions 20A along the circumferential direction of the head portion 3, with straight lines between the apex portions 20A. It may be a hexagonal shape having an inner side surface 21A parallel to the axial direction of the shaft portion 4 from each side of the hexagonal shape.

Now, in order to join parts that require a high screw tightening load, such as joining hard pieces of wood together, it is necessary to perform a joint that requires a high torque when rotating the screw, without camming out the torque generated by the tool. It is essential to ensure that the force is transmitted to the screw and that the force is strong enough to prevent the screw from breaking even when tightened with high torque.

In order to suppress the cam-out, it is effective to form the recess of the screw deeply. If the thickness of the screw head is increased in order to form a deep recess, the amount of protrusion of the screw head from the surface of the object to be fastened increases. On the other hand, if the recess is formed deep without increasing the thickness of the head of the screw, the diameter of the lower surface of the head will be larger than that of the shank due to the relationship between the size of the recess and the diameter of the shank where the screw thread is formed. It becomes necessary to provide a large enlarged diameter portion.

However, since the enlarged diameter part acts as a resistance when it sinks into the object to be fastened when the screw is tightened, the larger the diameter of the enlarged diameter part, the higher the torque required to tighten the screw in order to ensure the strength of the screw. As a result, it is difficult to obtain the effect of ensuring the strength of the screw.

On the other hand, in the screw 1A of the present embodiment, the shape of the recess 2A, the diameter of the enlarged diameter portion 5, and the length of the shaft portion 4 along the axial direction are defined, so that the screw 1A is expanded by the fastening operation of the screw 1A. An increase in load when the diameter portion 5 sinks into the object to be fastened is minimized, and reliable torque transmission from the driver bit 201 to the screw 1A becomes possible. Thus, without increasing the thickness of the head portion 3, problems such as reliable transmission of high torque, securing the strength of the screw 1A, and suppression of increase in the torque required for tightening the screw 1A can be achieved. Therefore, applications to which the screw 1A is applied are not limited to the cover construction method described above, but are effective in fastening members with a high screw tightening load, such as fastening hard wooden pieces.

1A... Screw, 2A... Recess, 20A... Top, 21A... Inner surface, 22A... Guidance recess, 3... Head, 30... Top surface, 31... Bearing surface 32 Bearing surface reference surface 33 Convex portion 4 Shaft portion 40 Screw thread 5 Expanded diameter portion 50 Tapered surface 50a, Connection surface under seat surface 50b Curved surface 51 Starting point 101 Base 102 Slate material 104 Sheet metal 200 Bit 201 Driver bit

Claims (14)

a head formed with a recess into which the driver bit is fitted;
a shank on which a screw thread is formed;
An enlarged diameter portion having a larger diameter than the shaft portion is provided between the bearing surface formed on the shaft portion side of the head portion and the shaft portion,
the recess has at least three apexes along a circumferential direction of the head that rotates about the shaft;
A screw between said apexes consisting of a straight line or a combination of straight and curved lines or a curved line that is concave towards the center of said head. 2. The screw of claim 1, wherein the recess has an inner surface parallel to the axial direction of the shank. The screw according to claim 1 or 2, wherein the head portion has a convex portion that protrudes along the axial direction of the shaft portion in a direction opposite to the side on which the enlarged diameter portion is provided. The depth of the recess is equal to or greater than the thickness of the head, and the diameter of the outer circumference passing through the top of the recess is greater than or equal to the diameter of the shaft. or the screw according to item 1. The screw according to any one of claims 1 to 4, wherein the recess has a depth of 1.6 mm or more and 2.5 mm or less. The screw according to any one of claims 1 to 5, wherein said recess comprises a guide recess for guiding a bit of a driver bit into said recess. The enlarged diameter portion has a tapered surface whose diameter increases from the shaft portion toward the head portion,
The screw according to any one of claims 1 to 5, wherein an angle formed by the tapered surfaces is 70° or more and 115° or less. The enlarged diameter portion has a tapered surface whose diameter increases from the shaft portion toward the head portion,
The screw according to claim 6, wherein the angle formed by the tapered surfaces is 38° or more and 115° or less. The length along the axial direction of the shaft portion from the starting point of the enlarged diameter portion where the shaft portion and the enlarged diameter portion intersect to the seat surface of the head is 1.5 mm or more and 3.5 mm or less. The screw according to any one of claims 1 to 8. The recess has six apexes along the circumferential direction of the head, and each of the apexes is configured with a curved line that protrudes toward the outer circumference of the head. , a curved line that becomes concave toward the center of the head. The screw according to any one of claims 1 to 10, wherein the head has a thickness of 1.2 mm or more and 2.4 mm or less. The screw according to any one of claims 1 to 11, wherein the bearing surface of the head is provided on the outer circumference of the enlarged diameter portion, and the bearing surface is a flat surface. The enlarged diameter portion has a diameter at a portion separated by 1.2 mm or more along the axial direction of the shaft portion from the bearing surface of the head portion is equal to or less than the diameter of the screw thread of the shaft portion. 13. A screw according to any one of claims 12 to 14. 14. The screw according to any one of claims 1 to 13, wherein the plurality of screws are connected by a connecting member in a direction perpendicular to the axial direction of the shaft portion, and spirally wound from the inner peripheral side to the outer peripheral side. screws.

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