JP5663467B2 - Drill screw - Google Patents

Description

  The present invention relates to a drill screw that penetrates a roofing material and fastens it to a base material.

  Conventionally, a concrete slate roofing material has been used as a roofing material for wooden houses and the like. When renovating such a roofing material, a construction method is often employed in which a new roofing material is erected from the roofing material without peeling off the roofing material. When this construction method is adopted, it is necessary to use a drill screw to attach a metal object such as a tight frame for attaching a new roofing material to the existing roofing material and fasten it to the base wood.

  As such a drill screw, a drilling tapping screw (see JISB1125) having a screw tip formed at a pointed tip and a drill screw (see JISB1124) having a screw tip formed at a cutting edge are known. The cutting edge of this drill screw has a point at the lower end and is formed in parallel with the axis of the screw at a position slightly smaller than the screw diameter, with a cutting blade extending at an angle of 100 to 110 degrees to the left and right from the point position. Left and right side blades, and blade surfaces (shoulders) are formed at the left and right ends where the cutting blade and the side blades intersect.

  Also, as shown in Patent Document 1, as a drill screw, the cutting edge of the screw tip is bonded with two half cones having different inclinations of the bus bar while aligning the axis and the base end position and shifting the tip end position. There is also known one in which a cutting edge is formed on the edge of a step formed by shifting the tips of two half cones.

Utility Model Registration No. 3028024

  By the way, the old concrete slate roofing material has a hard property because it contains more cement and sand than the current roofing material. For this reason, when a metal object is pierced through a concrete slate roofing material with a drill screw and fastened to an underlying wood, the tip of the point of the drill screw becomes worn and rounded in the process of cutting the roofing material and penetrates the roofing material. There was a problem that I could not. In addition, in the case of cutting edges, if the roof material is drilled, the cutting edges and the blade surfaces (shoulders) on both the left and right sides cannot be cut quickly due to cement or sand, and the cutting edges melt due to frictional heat. There was also.

  Moreover, in the drill screw of patent document 1, the sharp front-end | tip of a cutting blade is easy to wear with the cement and sand of roofing material, and loses the function as a cutting blade early and late. Moreover, the cutting blade that can be cut is only a single blade on the side facing the roofing material in the rotation direction, and the cutting performance is lower than that of the double blade.

  The present invention has been made in view of such problems, and even if it is a roof material made of a hard material, it stably maintains the function as a cutting edge and reliably penetrates the roof material to make the base wood A drill screw that can be fastened to a screw is provided.

The present invention provides a drill screw in which a cutting edge is formed at a lower end portion following a threaded portion of a shaft portion and penetrates a concrete slate roofing material and fastened to a base material. A pair of cutting blades are formed at the symmetrical positions by the notches, and each cutting blade is in contact with the linear cutting blade and the linear cutting blade that extends linearly in a tapered manner toward the vicinity of the lower end toward the lower end. The arc-shaped cutting blade extends in an arc shape, and the arc-shaped cutting blade is continuous with the other arc-shaped cutting blade at the lower end, so that the cutting edge is viewed from the side facing the cutting surface of the cutting blade. The lower end of the cutting edge is formed in an arc shape .

According to the present invention, the cutting edge formed at the lower end portion of the shaft portion of the drill screw has a lower end toward the lower end by forming the notch portion at the position that is point-symmetric with respect to the shaft center of the shaft portion. A linear cutting blade that extends linearly in a tapered manner to the vicinity, an arc-shaped cutting blade that extends in an arc shape in contact with the linear cutting blade and that is continuous with the other arc-shaped cutting blade at the lower end; A pair of cutting blades. Thus, when the drilling operation is started by bringing the lower end of the drill screw into contact with the roof material, the roof material is cut so that the pair of arc-shaped cutting blades extending from the lower end follows the rotational shape. Here, by cutting the roofing material made of hard material, even as a part of the outer peripheral edge of the arc-shaped cutting edge is worn, arcuate cutting edge by notch on exists toward the axial direction As long as the cutting ability is not lost, the drilling work on the roofing material can be continued.

  As a result, even a roof material made of a hard material can stably maintain the function as a cutting blade, and can reliably pass through the roof material and be fastened to the base wood.

  According to the present invention, even a roof material made of a hard material can stably maintain the function as a cutting edge and can be securely passed through the roof material and fastened to the base wood.

It is a front view which shows one Embodiment of the drill screw of this invention. It is an enlarged view of the cutting edge of the drill screw of FIG. FIG. 3 is a bottom view of the cutting edge of FIG. 2. It is the sectional view on the AA line of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 4 show an embodiment of a drill screw 1 of the present invention.

  The drill screw 1 includes a head portion 2 and a shaft portion 3, and the head portion 2 is formed in a substantially pan-like shape and is formed with a cross hole. The shaft portion 3 of the drill screw 1 is formed with a screw portion 4 over a set length that leaves the lower end portion from the upper portion in the vicinity of the head portion 2, and a cutting edge 5 is formed at the lower end portion following the screw portion 4. ing.

This cutting blade tip 5 is a pair of cutting blades 7 formed by forming a notch 6 over the entire lower end so that its cross-sectional area gradually decreases toward the lower end at a point symmetric with respect to the axis of the shaft 3. have. Each cutting blade 7 includes a linear cutting blade 8 that linearly extends toward the lower end toward the lower end, and an arc-shaped cutting blade that extends in contact with the linear cutting blade 8 in an arc shape. 9 and is formed to be continuous with the other arcuate cutting blade 9 at the lower end. In other words, the linear cutting blade 8 and the arcuate cutting blade 9 are formed so as to share a tangent line, and the pair of arcuate cutting blades 9 have an intersection at their lower ends. They are formed so as to be continuous with each other. Further, as shown in FIGS. 3 and 4, the cutting surface (rake surface) of each cutting blade 7 has a rake angle slightly inclined toward the rotation direction with respect to a horizontal plane passing through the axis.

  The case where the roof screw is penetrated and fastened to the base material using the drill screw 1 configured as described above will be described.

When the drilling operation is performed by bringing the lower end of the drill screw 1 into contact with the roofing material, the roofing material is cut so that a pair of arc-shaped cutting blades 9 extending from the lower end follow the rotational shape. Here, when the roof material is formed of a hard material containing a lot of sand and cement, it is inevitable that a part of the outer peripheral edge of the arcuate cutting blade 9 that is cut in contact with the roof material is worn. . However, if the arc-shaped cutting edge 9 by the outer circumferential even partially worn edge, notch on 6 of arc-shaped cutting edge 9 by cutting the roofing material is left toward the axial direction In this case, the cutting function is not lost, and the cutting operation can be continued.

In other words, when cutting roofing material made of hard material, assuming that it can not be avoided that the cutting edge to perform the initial cutting is small worn round, advance the arcuate cutting edge 9 the notch on 6 are those designed to ensure a predetermined length toward the axial direction.

  Thereby, even if it is a roof material consisting of a hard material, the pair of arc-shaped cutting blades 9 can reliably cut and penetrate the roof material. And it can cut efficiently with a double blade.

  On the other hand, when the arcuate cutting blade 9 penetrates the roof material, the linear cutting blade 8 that continues to the arcuate cutting blade 9 and gradually extends toward the head 2 becomes an arcuate cutting blade 9. The peripheral edge of the through hole is cut and expanded, and finally a through hole having an inner diameter corresponding to the outer diameter of the cutting edge 5 is formed in the roofing material. Then, the threaded portion 4 can be guided to the base wood through the through hole of the roof material, and the threaded portion 4 can be screwed into the prepared hole formed in the base wood by the cutting blade 7 and fastened. At this time, the cutting blade 7 cuts the roof material made of a hard material, so that even if a part of the outer peripheral edge is worn and the diameter is reduced, the screwing performance to the base wood is improved accordingly. .

  Specifically, when cutting a single roofing material made of a hard material with the tip or cutting edge of a conventional drill screw, the cutting edge is deformed by wear or burned by frictional heat. While it cannot be melted and penetrated, the drill screw 1 of the present invention has an ability to penetrate 4 to 5 roof materials made of a hard material.

DESCRIPTION OF SYMBOLS 1 Drill screw 2 Head 3 Shaft 4 Screw part 5 Cutting edge 6 Notch 7 Cutting blade 8 Straight cutting blade 9 Arc-shaped cutting blade

Claims (1)

In a drill screw in which a cutting edge is formed at the lower end portion following the thread portion of the shaft portion and penetrates the concrete slate roofing material and fastened to the base material, a position that is point-symmetric with respect to the shaft center of the shaft portion in the cutting blade tip A pair of cutting blades are formed by the notches, and each cutting blade linearly extends toward the lower end to the vicinity of the lower end in a straight line, and is in an arc shape in contact with the linear cutting blade. An arcuate cutting blade extending, and the arcuate cutting blade is continuous with the other arcuate cutting blade at the lower end so that the lower end of the cutting edge is viewed from the side facing the cutting surface of the cutting blade. A drill screw characterized by being formed in an arc shape .

Images