JPH078614U - Screw nail - Google Patents

Abstract

(57) [Summary] [Purpose] To make it possible to inexpensively manufacture screw nails with markedly improved fastening strength. [Structure] Each ridge 4 is formed in a trapezoidal cross section such that an outer peripheral surface 4c between a leading flank 4a and a trailing flank 4b spreads in an appropriate range along the circumferential direction. The leading flank 4a of the ridge 4 is formed to be gently inclined toward the valley portion 5, and the leading flank 4a is formed to be abruptly inclined toward the valley portion 5. Since the ridges 4 have a trapezoidal shape, the easiness of processing by rolling is not impaired, and the ridges 4 are hardly crushed when driven into the fastened member 6. Further, since the follow-up flank 4b acts as a large resistance to the rotation of the shaft portion 1 in the pulling-out direction, the fastening strength can be improved.

Description

[Detailed description of the device]

[0001]

[Prior art]

 The present invention relates to an improvement in a screw nail in which a plurality of spiral ridges are formed on the outer peripheral surface of a shaft portion, and the ridges increase resistance to pulling out to improve fastening strength. Is.

[0002]

[Prior art]

 As described above, in the screw nail formed by forming a plurality of ridges in a spiral shape on the outer peripheral surface of the shaft portion, generally, the cross-sectional shape of each ridge is formed in an arc shape. There is a problem that the frictional resistance of the ridges against the member to be fastened cannot be increased and the fastening strength cannot be sufficiently improved.

Therefore, in Japanese Utility Model Laid-Open No. 3-130902 as a prior art, the cross-sectional shape of each ridge is formed into a sharply pointed triangle, and the valley (groove) between adjacent ridges is crossed. It is proposed to form a groove toward the outer side of the radius in plan view.

[0004]

[Problems to be solved by the device]

 However, as in this prior art, when each ridge is formed into a sharply pointed triangle, it is not necessary to use a steel plate or a shaped steel, such as when a decorative steel plate or gypsum board is fastened to a structural material in a building. When driven into a hard member to be fastened, each ridge is crushed by driving into the fastened member, and the ridges hardly function as resistance to the fastened member, and the fastening strength cannot be sufficiently improved. There was a problem.

Further, this prior art has a problem that it is difficult to manufacture. In other words, in order to process a ridge on the shaft of this type of screw nail, generally, while the shaft is sandwiched between a pair of dies, both dies are moved relative to each other, and the dies are The rolling is performed by rolling the shank while plastically deforming the outer peripheral surface of the shank so as to follow the irregularities formed on the die. In order to form a convex ridge and a valley that is concave outward in the radial cross-section, the shaft must be plastically deformed significantly.Therefore, in terms of machining accuracy and die durability, it should be machined by rolling. Therefore, it was difficult to mass-produce at low cost.

An object of the present invention is to provide a screw nail having a markedly improved fastening strength in a form that can be manufactured extremely easily.

[0007]

[Means for Solving the Problems]

 In order to achieve this object, the present invention forms a plurality of ridges in a spiral shape by rolling on the outer peripheral surface of a shaft portion having a head portion at one end and a pointed portion at the other end. In the screw nail, the cross-sectional shape of each of the ridges is a substantially trapezoidal shape in which the outer peripheral surface of the ridge extends between the leading flank and the trailing flank with an appropriate width along the circumferential direction. In addition, each ridge is formed so that the leading flank is gently inclined toward the valley and the trailing flank is depressed at a large angle toward the valley in a cross-sectional view.

[0008]

[Operation and effect of the device]

 With this structure, since the cross-sectional shape of each ridge is a trapezoidal shape that is strong against external forces, even when it is driven into a hard member to be fastened such as steel plate or shaped steel, each ridge is driven by driving. Is almost never deformed, and when the shaft portion is driven into the fastened member, the fastened member is fitted in the valley between the ridges, in other words, The leading flank and the trailing flank of the ridge are in close contact with the member to be fastened.

Further, since each ridge has a spiral shape, when an external force that pulls it out is applied to the shaft, the shaft protrudes from the head toward the pointed portion. The spiral is rotated in the direction opposite to the rotation direction, and therefore the magnitude of the resistance against the slip-out of the shaft portion (in other words, the fastening strength) depends on the axial portion and the fastened member in the axial direction. It depends on the frictional resistance between the ridges and the magnitude of the frictional resistance in the circumferential direction between the ridge on the trailing side of the ridge and the member to be fastened.

In this case, since the ridges are spiral, the leading flanks of the ridges directly act as resistance to the external force in the axial direction, but the leading flanks of the ridges are located in the valleys. By gently sloping toward the front, the contact area between the leading flank of the ridge and the member to be fastened can be increased, so that the frictional resistance between the shaft portion and the member to be fastened in the axial direction can be increased. it can.

On the other hand, since the follower flank is formed so as to drop toward the valley portion at a large angle, the follower flank and the member to be fastened are in a state of being meshed with each other, so that the shaft portion comes off. A large frictional resistance acts between the tracking flank and the member to be fastened against the external force rotating in the direction. In this way, the frictional resistance along the axial direction and the frictional resistance in the direction in which the shaft is slipping out can be increased with almost no deformation of each ridge by driving, so that the fastening strength is significantly improved. Can be improved.

Further, since the cross-sectional shape of each ridge is a simple trapezoidal shape, it can be processed extremely easily by rolling. Therefore, according to the present invention, there is an effect that a screw nail with markedly improved fastening strength can be manufactured at low cost. Further, according to the structure of claim 2, since the outer peripheral surface of each ridge is tapered so that the diameter increases toward the head, each ridge is driven into the member to be fastened. Since the outer peripheral surface of the ridge strongly adheres to the member to be fastened, the frictional resistance at the outer peripheral surface of each ridge significantly increases compared to the case where the outer peripheral surface of the ridge is formed in a straight shape. In addition, the trough is tapered so that the diameter decreases from the part near the point to the part near the head, so that when the pull-out external force acts on the shaft, the flank on the leading side of the ridge Is in a state of being stretched against the member to be fastened, and therefore, the fastening strength can be further improved.

[0013]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 indicates a shaft portion having a head portion 2 formed at one end and a pointed portion 3 formed at the other end. The shaft portion 1 has a plurality of spirally extending threads on its outer peripheral surface. In the example, 6 ridges 4 are formed so as to be clockwise (direction A) when viewed from the head 2 toward the pointed portion 3 (the spiral direction may be opposite). ).

Each of the ridges 4 has a leading flank 4a facing forward in the direction of rotation (A direction) of the spiral as viewed from the head 2 toward the pointed portion 3, and on the opposite side to the flank 4a. An outer peripheral surface 4c is formed in a substantially trapezoidal cross section so as to extend concentrically with the shaft portion 1 along the circumferential direction with an appropriate width E between the tracking flank 4b located. Further, each of the ridges 4 is formed such that the leading flank 4a is gently inclined toward the valley portion 5 and the trailing flank 4b is depressed toward the valley portion 5 at a large angle in a cross sectional view. There is. That is, the angle α formed between the leading flank 4a and the tangent line O ′ is small, and the angle β formed between the trailing side flank 4b and the tangent line O ″ is large. In this case, both flanks 4a and 4b are crossed. It may be linear or arcuate in a plan view, and the angle β may be smaller than 90 degrees.

Further, as conceptually shown in FIG. 1B, the outer peripheral surface 4c of each of the ridges 4 has a diameter D1 that increases from a portion closer to the pointed portion 3 toward a portion closer to the head 2. On the other hand, the valley portion 5 has an extremely loose taper so that the diameter D2 of the valley portion 5 becomes smaller from the portion closer to the pointed portion 3 toward the portion closer to the head 2. It is formed like a pad.

When forming the ridge 4 on the straight shaft portion 1 by rolling, the height difference H between each ridge 4 and the valley portion 5 is large at the portion close to the head 2 and sharp. By reducing the size in the portion closer to the portion 3, the outer peripheral surface 4c of the ridge 4 and the valley portion 5 can be formed in a tapered shape along the axial direction as in the embodiment. In the case of a screw nail for a steel plate, when the diameter D1 of the outer peripheral surface of the ridge 4 is 2.6 mm, the height difference dimension H from the valley 5 to the outer peripheral surface 4c of the ridge 4 is about 0.15 mm. The width E of the outer peripheral surface 4c of the strip 4 may be set to about 0.4 mm. Also, the nails are hardened.

In the above-mentioned configuration, as shown in FIG. 3, for example, a plaster board 8 having a decorative steel plate 7 stacked on a section steel (member to be fastened) 6 having a C-shaped cross section, for example, is fastened with this screw nail. You can In this case, since each of the ridges 4 has a substantially trapezoidal cross section, it can be driven into the shape steel 6 with almost no crushing. In the driven state, as shown in FIG. 6 is fitted, in other words, the outer peripheral surface 4c of the ridge 4 and both flanks 4a, 4b are in close contact with the die steel 6.

Since each of the ridges 4 has a spiral shape, when a pulling external force is applied to the shaft portion 1 driven into the shape steel 6, the ridges 3 are seen from the head 2 when the pointed portion 3 is viewed. The direction of rotation of the spiral of No. 4 (direction A) and the opposite direction (direction of B), in other words, rotation in the same direction as the direction of rotation of the spiral of the ridge 4 when viewed from the pointed portion 3 toward the head 2. Therefore, the fastening strength of the screw nail depends on the frictional resistance between the shaft portion 1 and the shape steel 6 in the axial direction and the circumference generated between the tracking flank 4b and the shape steel 6. It depends on the magnitude of the frictional resistance in the direction.

In that case, frictional resistance along the axial direction occurs between the outer peripheral surface 4c of the ridge 4 and the leading flank 4a and the shaped steel, but the outer peripheral surface 4c of each ridge 4 is attached to the head 2. Since the outer peripheral surface 4c of the ridge 4 is strongly adhered to the die steel 6, the outer peripheral surface 4c has a straight shape because the outer peripheral surface 4c has a tapered shape with a large diameter toward the outer peripheral surface 4c. The frictional resistance in the axial direction at the position of the outer peripheral surface 4c is remarkably increased as compared with the case.

Further, since the leading flank 4 a of the ridge 4 is gently inclined toward the valley 5, the contact area between the leading flank 4 a of the ridge 4 and the die steel 6 is increased. Moreover, since the valley portion 5 has a taper shape in which the diameter becomes smaller from the portion close to the pointed portion 3 toward the portion 2 closer to the head, as shown exaggeratedly in FIG. When the external force is applied, the leading flank 4a is in a state of being stretched with respect to the die steel 6, and the contact area between the leading flank 4a and the die steel 6 can be increased, and the leading flank 4a can be increased. By being in a state of being stretched with respect to the shape steel 6, the frictional resistance at the location of the leading flank 4a can be significantly increased.

Further, since the follow-up flank 4b is depressed toward the valley 5 at a large angle β, the follow-up flank 4b and the shape steel 6 are in a state of being meshed with each other, so that the pull-out external force of the shaft portion 1 is increased. A large circumferential frictional resistance is generated between the trailing flank 4b and the die steel 6 against the rotational force that acts at that time. In this way, the frictional resistance at the location of the outer peripheral surface 4c can be remarkably increased, and the axial frictional resistance at the location of the advancing side flank 4a can be remarkably increased. It occurs between the trailing side flank 4b and the shaped steel 6. The synergistic effect of the three factors, which can significantly increase the frictional resistance in the circumferential direction, can significantly improve the fastening strength.

Further, the cross-sectional shape of each convex strip 4 is a simple trapezoidal shape and can be processed extremely easily by rolling, so that the manufacturing cost does not increase. The total length L of the screw nail is 32 mm, the outer diameter D1 is about 2.60 mm, the plate thickness t1 of the shaped steel 6 is 2.3 mm, the thickness t2 of the gypsum board 8 is 12 mm, and the thickness t3 of the steel plate 7 is 0. In the case of 3 mm, after driving as shown in FIG. 3, the plaster board 9 is pushed down, and then the clamper 9 is locked to the head 2 as shown by the chain double-dashed line, and the pull-out dimension S of the shaft 1 is removed. When the pull-out force required to reach 2 mm (that is, the initial pull-out force) F 1 is compared with the conventional product, in the case of the conventional product in which the ridge 4 is formed in an arcuate cross section, the initial pull-out force F 1 is 70 kg to 100 kg. On the other hand, in the present embodiment, the pulling force F1 of about 180 kg is required, and it is proved that the product of the present invention has a remarkable initial pulling resistance (that is, the fastening is not loose easily). It was

Further, as shown by the one-dot chain line in FIG. 3, under the same conditions as above, the screw nail in the tightened state is pressed from the pointed portion 3 in the axial direction by the pressing body 10, and the pressing body 10 is pressed. When the force F2 required to contact the inner surface of the shaped steel 6, that is, the magnitude of the total load required for drawing is compared with the conventional product, the total load F2 is about 80 to 130 kg in the conventional product. Therefore, the screw nail of the present embodiment requires a total load F2 of about 280 kg, and the fastening strength is high in terms of the total load (that is, the nail cannot be easily pulled out even if the fastening is loose). Proved.

In the present application, various dimensions such as the number of the ridges 4 and the height dimension of the ridges 4 from the valley portion 5 are appropriately changed according to various conditions such as the material and thickness of the member to be fastened. Not to mention what you can do. When the present invention is carried out as described above, due to an error in rolling, etc., at a part of the shaft part 1 (particularly a part near the head part 2), as shown in FIG. The shape may be somewhat deformed, such as when 5 is in a doubled state (in this case, too, the leading flank 4a is gently inclined and the trailing flank 4b is rapidly inclined toward the valley 5). It does not change, and the cross-sectional shape as shown in FIG. 6 may be formed over the entire length).

In the present invention, most of the entire length of the ridge 4 may be formed in a shape within the scope of the utility model registration claim.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, in which (a) is a front view of the whole and (b) is a conceptual diagram showing an inclined state of a ridge and a valley.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a diagram showing a fastening state.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

5A is a conceptual diagram showing a relationship between an outer peripheral surface of a ridge and a member to be fastened, and FIG. 5B is a conceptual diagram showing a relationship between a valley portion and a member to be fastened.

FIG. 6 is a cross-sectional view of a portion having a different shape during rolling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft part 2 Head part 3 Pointed part 4 Convex ridge 4a Leading side flank 4b Tracking side flank 4c Outer peripheral face 5 Valley part 6 Steel as an example of fastened member

Claims (2)

[Scope of utility model registration request] 1. A screw nail formed by rolling a plurality of ridges in a spiral shape on the outer peripheral surface of a shaft portion having a head portion at one end and a pointed portion at the other end, The cross-sectional shape of each of the ridges is formed into a substantially trapezoidal shape in which the outer peripheral surface spreads along the circumferential direction with an appropriate width between the leading flank and the trailing flank of the ridge, and each ridge. A screw nail, characterized in that, in a cross-sectional view, the ridge is formed so that the leading flank is gently inclined toward the trough and the trailing flank is depressed toward the trough at a large angle. 2. The "periphery" according to claim 1, wherein the outer peripheral surface of each of the ridges is tapered along the axial direction such that the portion near the pointed portion has a small diameter and the portion near the head portion has a large diameter. On the other hand, the screw nail is characterized in that each of the troughs is formed in a gentle taper along the axial direction so that the portion near the pointed portion has a large diameter and the portion near the head portion has a small diameter.