JP3237989U - Crack prevention structure for screw head drill bit and flat drill teal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crack prevention structure for a drill bit of a screw head and a flat drill teal, which discharges chips when screwing a wood screw and prevents the occurrence of cracks. SOLUTION: A screw having a conical head 12 and a cylindrical body 13, provided with a flange 11 at the end of the head, extending the other end to connect to the cylindrical body, and circling multiple times around the outer periphery of the cylindrical body. A mountain 14 is provided, a plurality of drill bits 15 protruding from the head are provided, and a flat drill portion 20 having two flat surfaces 21 formed on both sides of the cylinder 13 is provided at the tip of the cylinder 13. The tip of the screw is converged toward the center line 19 passing through the axis of the screw to form a cutting edge 24, and two convex curved surfaces 22 are formed by extending from the surface of a cylinder on their side edges to form the same side of two planes. Form a blunt and sharp edge adjacent to. [Selection diagram] Fig. 1

Description

The present invention relates to a drill bit applied to the head portion of a crack prevention screw, a wood screw or other screw, and further relates to a crack prevention structure of a flat drill teal.

The use of screws with different shapes depending on the material of the product is related to speeding up drilling, increasing the amount of waste discharged, and saving labor when tightening. By researching and developing various screws in consideration of these conditions, the ideal effect for practical use is achieved.

However, when the screw is screwed into the product, the product is scraped and chips are constantly generated and discharged out of the hole. Since some products are made of fragile materials, when the screw is screwed in, the discharge of chips may be delayed and accumulated, and the sinking head may cause the product to crack. .. The cause is that the diameter of the head portion is larger than the diameter of the hole, and chips accumulate and cause cracks in the hole wall.

In addition, for some types of threads, emphasis is placed on the thread design of the drill teal to improve the speed of shaving or drilling. In addition, some screws emphasize and improve the design of the waste discharge groove of the teal. However, when the screw is screwed into the product, the phenomenon of cracking still occurs, the dust cannot be completely stored in the hole, and the amount of waste discharged is lower than the amount of waste generated, so the crack occurs due to the dust that clogs the hole wall. do.
Therefore, overcoming these shortcomings existing in the prior art is a problem to be solved by the present invention.

Japanese Unexamined Patent Publication No. 7-217625 Japanese Unexamined Patent Publication No. 2000-27830 Re-table 2011-11288 Publication No.

The present invention provides a new wood screw, the main purpose of which is to adopt a drill bit structure to effectively solve the above-mentioned drawbacks existing in the prior art as a crack prevention structure for a flat drill teal.

In order to achieve the above object, the screw of the present invention has a head having a flange, a cylinder extending from the head, and a plurality of drills having multiple orbiting threads formed on the outer circumference of the cylinder and protruding from the head. The bit, the drill bit extends from the flange to the cylinder. Further, the flat drill portion has two planes formed on both sides of the front surface and the back surface of the cylinder body, and their tips intersect and converge with one virtual center line passing through the axis of the screw. By extending two convex curved surfaces from the surface of the cylinder and forming each convex curved surface in contact with the same side of the two planes, one blunt angle and one sharp blade portion are formed on both side edges of the plane. Formed, the width between the two blades is the width of the flat drill portion, the thickness between the two planes is the thickness of the flat drill portion, the thickness is less than half the width, and the width orbits the cylinder. It is smaller than the diameter of the thread circle. Two slopes are formed by extending from the convex curved surfaces on both sides of the flat drill portion toward the tip, and the tip converges to the above-mentioned converged intersection and becomes a cutting edge.
Among them, the drill bit and the center line form a sandwiching angle, or the drill bit is parallel to the center line. Alternatively, the drill bit forms an arc-shaped blade protruding outward or an arc-shaped blade recessed inward.

The screw of the present invention has effects such as reaming, drilling and expanding the diameter of the hole, allowing the head portion to smoothly enter the hole and preventing cracks in the product.

FIG. 1 is a diagram showing a first embodiment of the screw of the present invention. FIG. 2 is a diagram showing a cross section of a flat drill portion of the present invention. FIG. 3 is a diagram showing a second embodiment of the screw of the present invention. FIG. 4 is a diagram showing a third embodiment of the screw of the present invention. FIG. 5 is a diagram showing a fourth embodiment of the screw of the present invention.

As shown in FIGS. 1 and 2, the first embodiment of the screw 10 includes a head portion 12, a cylindrical body 13, and a flat drill portion 20 that are integrally molded. Among them, the head portion 12 exhibits a conical body, and the flange 11 is formed by extending from the end of the large diameter of the conical body, and the other end of the small diameter is connected to the cylindrical body 13.
A plurality of protruding drill bits 15 are provided on the surface of the head portion 12 along the one virtual center line 19 penetrating the axis of the screw 10 toward the outer peripheral direction of the center line 19. Each drill bit 15 is formed by extending from the bottom of the flange 11 toward the cylindrical body 13, and a narrow angle 16 is provided between the drill bit 15 and the center line 19, and the drill bit 15 is inclined with respect to the center line 19. is doing.

A thread 14 that orbits multiple times is formed on the outer periphery of the cylinder 13, the thread 14 is integrally formed with the structure of the cylinder 13, and the diameter 18 of the orbiting circle of the thread 14 is the diameter of the cylinder 13. Greater than 17.
The flat drill portion 20 is composed of two flat surfaces 21, two convex curved surfaces 22, and two slopes 23.
Among them, two planes 21 are formed on the front surface and the back surface of the cylindrical body 13, and the plane 21 is also inclined toward the center line 19 with respect to each other. The two convex curved surfaces 22 are extended from the outer surface of the cylindrical body 13, and each convex curved surface 22 is formed at an obtuse angle and an acute angle adjacent to the same side of the two planes 21 to form a blade 27 of the flat drill portion 20 (. See FIG. 2). The width 26 between the two blades 27 is the width 26 of the flat drill portion 20, the distance 25 between the two flat surfaces 21 is the thickness 25 of the flat drill portion 20, and the thickness 25 is smaller than half the width 26. The width 26 is smaller than the orbiting diameter 18 of one thread 14.
Two slopes 23 are located on both sides of the flat drill portion 20, one end of each slope 23 is connected to the convex curved surface 22, and the other end converges toward the above-mentioned center line and gathers with the plane 21 to cut. 24, and the blade 27 extends from the convex curved surface 22 to the cutting edge 24 along the slope 23.

When the screw 10 is screwed into the wood (not shown in the figure), the flat drill portion 20 scrapes wood chips with sharp blades 27 on both sides of the cutting edge 24, and the columnar body 13 cuts into the wood with the integrally formed screw thread 14. As a result, cracks can be prevented and shavings can be removed smoothly.
Next, when the screw 10 reaches the head portion 12 from the cylinder 13 with respect to the wood, the diameter of the head portion 12 gradually increases from the cylinder 13 toward the top end of the screw 10, so that the hole diameter is increased by the drill bit 15. At the same time as expanding the wood chips, the screws 10 are easily screwed in and the head portion 12 is embedded in the hole to hide the head, so that crack prevention and residual waste can be effectively obtained. The function of removal can be achieved.

FIG. 3 shows a second embodiment of the screw 10 of the present invention, the structure thereof of which is substantially the same as that of the first embodiment, in which the drill bit 15a is provided in parallel with the virtual center line 19 in a different portion. The drill bit 15a extends along the centerline of the screw.

FIG. 4 shows a third embodiment of the screw 10 of the present invention, the structure thereof is substantially the same as that of the second embodiment, and the difference is that the head portion 12b has an outwardly bulging shape.
Further, the drill bit 15b is an arcuate blade that extends vertically and projects outward.

FIG. 5 shows a fourth embodiment of the screw 10 of the present invention, the structure thereof of which is substantially the same as that of the second embodiment. It is a dented arc-shaped blade.

10 Thread 11 Flange 12, 12b Head 13 Cylindrical 14 Thread 15, 15a, 15b, 15c Drill bit
16 Square 17, 18 Diameter 19 Center line 20 Flat drill part 21 Plane 22 Convex curved surface 23 Slope 24 Cutting edge 25 Thickness 26 Width 27 Blade

Claims (5)

It is a crack prevention structure for the drill bit of the screw head and the flat drill teal.
A head part with a flange on the end face,
A cylinder extended from the head portion and
With a flat drill part provided at the other end of the cylinder,
Multiple orbiting threads are formed on the outer circumference of the cylinder.
A plurality of drill bits protruding from the surface of the head portion are formed by extending from a flange to the cylindrical body.
The flat drill portion forms two planes on both side surfaces of the cylinder, converges toward the center line of the cylinder, and intersects.
Two convex curved surfaces that are in contact with the sides of the two planes and extend from the outer surface of the cylinder toward the tip are formed.
The angle of contact between each convex curved surface and the two planes is an obtuse angle and an acute angle blade, the width formed by the two blades is the width of the flat drill part, the thickness of the plane is the thickness of the drill part, and the thickness is from half the width. Small, the width is smaller than the diameter of the orbiting circle of the thread,
The convex curved surface forms a slope toward the tip and converges at an intersection where the plane converges toward the center line to make a cut.
A crack prevention structure for screw head drill bits and flat drill teals. The crack prevention structure for the screw head drill bit and the flat drill teal according to claim 1, wherein the drill bit forms a narrow angle with the center line. The crack prevention structure for the screw head drill bit and the flat drill teal according to claim 1, wherein the drill bit is parallel to the center line. The crack-preventing structure for a screw head drill bit and a flat drill teal according to claim 1, wherein the drill bit forms an arc-shaped blade protruding outward. The crack prevention structure for the screw head drill bit and the flat drill teal according to claim 1, wherein the drill bit forms an arcuate blade recessed inward.

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