JPH07217625A - Wooden screw - Google Patents

Abstract

PURPOSE:To eliminate the necessity for forming a leading hole on the screwing-in position of a fastened material beforehand, prevent generation of crack on the fastened material by means of screwing-in, obtain comparative large fastening force even if a wooden screw is screwed in, and thrust the wooden screw easily without slipping fingers. CONSTITUTION:A notch part 15 provided a chisel shaped knife edge is formed on the top end part 13a of an axis part 13, and each height of ridges 14 of the axis part 13 is differentiated from each other per circumference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood screw, more specifically, it is not necessary to previously form a guide hole at a screwing position of a material to be fastened, and it is difficult for a material to be fastened to be cracked by screwing. The present invention relates to a wood screw that can obtain a relatively large tightening force even when screwed into a screw hole, and can be easily pierced without being slipped by a finger when being stabbed at a screwed position.

[0002]

2. Description of the Related Art A wood screw has a shaft portion having a sharp tip and a spiral screw thread formed on an outer peripheral surface, which is integrated with a head portion having a screwing groove for a driver. In the wood screw, a guide hole is formed in advance by a punch or the like at a screwing position of the stacked plate materials, and then a sharp tip portion is inserted into the guide hole and screwed by a driver to fasten both plate materials.

[0003]

However, although the above-mentioned conventional wood screw has a sharp tip, it is not as sharp as a needle, and even if the tip is strongly pressed against a plate material, It is difficult to stab a hard plate such as particle board. Therefore, it was necessary to open a guide hole when screwing.

In order to solve this problem, it is conceivable to sharpen the tip end to eliminate the guide hole, but if this is done, the state in which the wood screw is pierced into the plate material becomes point support and is not stable. As a result, it is presumed that the screw tip cannot be screwed in unless the user knows that the tip of the screw thread will be injured during rotation and firmly fix it with the fingertip.

Further, since the tip of the conventional wood screw is simply pointed in a conical shape, when the wood screw is screwed in, a large force pushing outward is applied to the screwed portion, and the plate material is easily broken. was there. Furthermore, the threads of wood screws are usually of the same height, so once a threaded wood screw is loosened and retightened, for example, valleys of even height are already formed inside the plate. Since the screw thread traces along this valley groove, there is a problem that the tightening strength is reduced. Moreover, there is a problem that the valley groove widens due to the tightening force of each time and the tightening cannot be sufficiently tightened by repeating this re-tightening only twice or three times.

The present invention has been made in view of the above circumstances, and it is not necessary to previously form a guide hole at a screwing position of a material to be fastened, so that the material to be fastened is less likely to be cracked by screwing.
An object of the present invention is to provide a wood screw that can obtain a relatively large tightening force even if it is screwed into the same screw hole and that can easily be pierced without being slipped by a finger at the time of being stabbed at the screwed position.

[0007]

A method according to the above-mentioned object.
The wood screw described has a notch provided with a chisel-shaped blade tip at the tip of the shaft, and the height of the thread of the shaft is different for each circumference.

[0008]

In the wood screw according to claim 1, when the tip of the wood screw is pressed against the screwed-in position of the material to be fastened, the sharp chisel-shaped blade edge pierces the material to be fastened relatively, so that the wood screw is guided to the screwed-in position in advance. Even if no holes are formed, wood screws can be stabbed into the material to be fastened. At this time, the height of the thread of the wood screw is different for each circumference, and the frictional force is larger than that of the normal wood screw, so that the length of the shaft portion is short or the pitch of the thread is small, for example. Even when the material to be fastened is hard and needs to be stabbed with a relatively large force, there is less risk that the finger may slip and injure the stab at the time of piercing, or the piercing force of the wood screw may be reduced.

After that, when the pierced wood screw is screwed in with a screwdriver, the sharp chisel-shaped cutting edge is screwed into the inside of the material to be fastened, so that the threaded portion of the material to be fastened is unlikely to crack.

When a wood screw is screwed into the material to be fastened, the thread of the shaft portion has a different height for each circumference in this way. Therefore, the valley groove formed in the screwed portion of the material to be fastened also has the same circumference. Formed with different depths. Therefore, when loosening the screwed wood screw once and tightening it again, the screw thread does not trace the valley groove in the fastened material as it is, but the high thread portion and the shallow groove portion in the fastened material And a relatively large tightening strength is obtained.

[0011]

Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. 1 is a perspective view of a wood screw according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view of the tip portion thereof, and FIG. 3 is a bottom view thereof.
FIG. 4 is a perspective view showing a piercing state of a wood screw, FIG. 5 is a sectional view showing a fastening state of a material to be fastened with the wood screw, and FIG. 6 is an enlarged sectional view of a main part of the screwed wood screw.

As shown in FIG. 1, a wood screw 10 according to an embodiment of the present invention is a wood screw made of, for example, stainless steel or steel.
2 is formed, and the tip portion 13a has a conical pointed shaft portion 13
Further, a thread 14 having a predetermined pitch is formed over the entire length thereof.

The screw thread 14 is composed of a large diameter portion 14a and a small diameter portion 14b whose heights are different for each circumference, and as shown in FIGS. 2 and 3, on the outer peripheral portion of the tip portion 13a, The notch 15 that is a V-shaped groove with an opening angle of 90 degrees
Is formed along the axial direction of. By forming the notch portion 15, a sharp chisel-shaped blade edge 16 is provided at the tip portion 13a.

When the wood screw 10 is used, as shown in FIG. 4, two MDF plate members 17 and 18 which are one example of materials to be fastened are vertically stacked in advance. Next, when the shaft portion 13 of the wood screw 10 is grasped with a fingertip and the tip of the wood screw 10 is pressed against the screwing position of the upper plate member 17, a sharp chisel-shaped cutting edge 16 is formed at the tip of the shaft portion 13. The tip portion 13a pierces the plate material 17 deeply. This allows
Unlike the conventional wood screw, it is possible to easily fix the wood screw 10 before the screwing by piercing without providing a guide hole (not shown) at the screwing position in advance.

At this time, since the large diameter portions 14a and the small diameter portions 14b are alternately arranged over the entire length of the shaft portion 13, for example, the length of the shaft portion 13 is short or the pitch of the screw thread 14 is small. Even if the blade is small or the plate material 17 with which the blade tip 16 pierces is hard and needs to be pierced with a comparatively large force, the wood screw 10 of this means has irregularities as long as the shaft portion 13 is lightly grasped. Since the frictional resistance is larger than that of the wood screw 10, there is less risk that the finger may slip when piercing, resulting in injury or the piercing force of the wood screw 10 becoming smaller.

The pierced wood screw 10 is then screwed in by a screwdriver (not shown). At this time, the sharp chisel-shaped cutting edge 16 provided at the tip is screwed into the plates 17 and 18 so as to bite into them, so that cracks are unlikely to occur in the screwed portions of the plates 17 and 18. Since the screw thread 14 of the shaft portion 13 has a different height for each circumference, as shown by the solid line in FIG. 6, the threaded portions of the plate members 17 and 18 into which the wood screw 10 is screwed in similarly have the same circumference. Valley 17 with different depth
a and 17b are formed.

As a result, when the screwed wood screw 10 is once removed and then tightened again, the screw thread 14 has the troughs 17a, 1
Do not trace 7b as it is. That is, as shown by the chain double-dashed line in FIG.
Since “a” is pushed in, a relatively large tightening strength can be obtained even when re-tightening. Although this effect is not constant depending on the conditions such as the hardness of the material to be fastened and the tightening force, it can usually be continued up to several re-tightenings.

The present invention has been described above with reference to the drawings. However, the present invention is not limited to this embodiment, and the present invention includes a design change and the like without departing from the scope of the invention. For example, in the embodiment, the shape of the cutout is a V-shaped groove, but the shape is not limited to this, and may be, for example, a U-shaped groove or a circular arc groove. Further, the opening angle in the case of the V-shaped groove is not limited to 90 degrees and may be any angle. further,
The length of the notch may be any length.

In the embodiment, the wooden plate is used as the material to be fastened, but the material is not limited to this, and any other material such as a thin plastic plate or a rubber plate may be used.

[0020]

In the wood screw according to the first aspect of the present invention, since the notch for providing such a chisel-shaped cutting edge is formed at the tip, as long as the tip of the wood screw is pressed against the material to be fastened. Since the sharp chisel-shaped cutting edge pierces the material to be fastened relatively deeply, the wood screw before screwing can be fixed without forming a guide hole in advance.

Further, since the height of the thread of the shaft portion is different for each circumference, for example, even when the material to be fastened has to be pierced with a comparatively large force, the finger gripping the shaft portion at the time of piercing. Is not slippery and can stab wood screws well. Furthermore, when screwing in, the sharp chisel edge is screwed into the inside of the material to be fastened, so the threaded portion of the material to be fastened is unlikely to crack.

Furthermore, when re-tightening the screwed wood screw, the thread is not traced directly to the valley groove formed in the material to be fastened, but to the high thread portion and the shallow groove portion. Contact with each other to obtain a relatively large tightening strength. Although this effect is not constant depending on the conditions such as the hardness of the material to be fastened and the tightening force, it is usually possible to continue the tightening several times.

[Brief description of drawings]

FIG. 1 is a perspective view of a wood screw according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the tip portion.

FIG. 3 is a bottom view of the same.

FIG. 4 is a perspective view showing a piercing state of a wood screw.

FIG. 5 is a cross-sectional view showing a fastening state of a material to be fastened with a wood screw.

FIG. 6 is an enlarged cross-sectional view of a main part of the screwed wood screw.

[Explanation of symbols]

 10 Wood Screw 11 Head 12 Fitting Groove 13 Shaft 13a Tip 14 Screw Thread 14a Large Diameter 14b Small Diameter 15 Cutout 16 Cutting Edge 17 Plate 17a Valley 17b Valley 18 Plate

Claims (1)

[Claims] 1. A wood screw, characterized in that a notch provided with a chisel-shaped cutting edge is formed at the tip of the shaft, and the height of the thread of the shaft is varied for each circumference.