JP7466973B1 - Hole saw - Google Patents

Abstract

[Problem] To provide a hole saw that does not trap cutting pieces. [Solution] The blade body 4 of the hole saw 1 has a disk-shaped base 5, an annular root 6 extending from the circumferential edge of the base 5 toward the tip, a plurality of blade portions 7 extending from the root 6 toward the tip, a tapered protruding blade portion 11 disposed at the center of the root 6 and extending further toward the tip than the blade portions 7, and a groove portion 12 formed in the root 6 between the blade portions 7a, 7b adjacent in the circumferential direction. [Selected Figure] Figure 1

Description

The present invention relates to a hole saw that can be attached to and detached from an electric drill.

Conventionally, as a hole saw that can be attached to and detached from an electric drill, there is an invention described in the following Patent Document 1, for example (hereinafter, the invention described in Patent Document 1 will be referred to as the "Publication 1 Invention"). The Publication 1 invention has an annular blade and a magnet part located at the center of the blade. According to the Publication 1 invention, the cutting chips are attracted to the magnet part during cutting, reducing the scattering and falling of the cutting chips.

JP 2018-62021 A

However, for example, if the cutting object is made of resin, the chips and pieces are not attracted to the magnet. Therefore, the chips get caught inside the blade, and it requires tedious work to remove them.

The present invention was proposed in light of these circumstances, and aims to provide a hole saw that does not trap cutting pieces.

To achieve the above object, the hole saw of the present invention is characterized by having an annular base portion, a plurality of blade portions extending from the base portion toward the tip, a tapered protruding blade portion extending further toward the tip than the blade portions at the center of the base portion, and a groove portion formed in the base portion between the blade portions adjacent in the circumferential direction.

The hole saw according to the present invention is characterized in that the groove portion is formed with a chamfering blade portion for chamfering the edge of the hole to be cut in the cutting object.

The hole saw of the present invention is characterized in that the outer surface of the base portion protrudes outward beyond the blade portion, and the chamfered blade portion protrudes toward the tip and extends from the inside to the outside of the base portion.

The hole saw according to the present invention is characterized in that the groove portion has a first groove portion curved in the direction opposite to the tip direction, and a second groove portion adjacent to the first groove portion in the circumferential direction and curved in the direction opposite to the tip direction, and the chamfering blade portion is raised in the direction toward the tip between the first groove portion and the second groove portion.

The hole saw according to the present invention is characterized in that the outer surface of the base portion is formed with a sloped portion that widens outward as it moves in the direction opposite to the tip.

The hole saw according to the present invention is characterized in that a flange portion is formed on the outer surface of the base portion below the sloped portion and protrudes outward beyond the sloped portion.

The hole saw according to the present invention has an annular base portion, a number of blade portions extending from the base portion toward the tip, a tapered protruding blade portion extending further toward the tip than the blade portions at the center of the base portion, and a groove portion formed in the base portion between adjacent blade portions in the circumferential direction. When a hole is cut in a cutting object, a piece of the cutting object is sandwiched between the blade portions, but instead of being supported by the protruding blade portions and separated from the blade portions, the piece falls toward the tip along the tapered shape. Therefore, the piece does not become sandwiched between the blade portions.

The hole saw according to the present invention has a chamfering blade formed in the groove for chamfering the edge of the hole to be cut in the cutting object. Thus, the edge of the hole in the cutting object is chamfered. In addition, since the chamfering blade is formed in the groove, no complex processing is required to form the chamfering blade.

In the hole saw of the present invention, the outer surface of the base portion extends outward beyond the blade portion, and the chamfered blade portion projects toward the tip and reaches from the inside to the outside of the base portion. Because the chamfered blade portion extends outward beyond the blade portion, the edge of the hole formed by the blade portion is chamfered by the chamfered blade portion.

The hole saw according to the present invention has a groove portion having a first groove portion curved in the opposite direction to the tip direction and a second groove portion adjacent to the first groove portion in the circumferential direction and curved in the opposite direction to the tip direction, and the chamfering blade portion is raised in the tip direction between the first groove portion and the second groove portion. The chamfering blade portion is formed as the boundary between the first groove portion and the second groove portion, so that the chamfering blade portion can be easily manufactured.

The hole saw of the present invention has a sloped surface formed on the outer surface of the base portion that widens outward in the direction opposite to the tip. The sloped surface chamfers the edge of the hole to be cut, resulting in a smooth edge of the hole.

The hole saw according to the present invention has a flange portion formed on the outer surface of the base portion below the sloped portion, which protrudes outward from the sloped portion. The flange portion abuts against the edge of the hole to be cut, restricting the movement of the hole saw in the insertion direction relative to the hole.

FIG. 1 is a side view of a hole saw according to a first embodiment of the present invention. FIG. 2 is a side view of a hole saw according to a second embodiment of the present invention. FIG. 3 is a top view of a hole saw according to a second embodiment of the present invention.

The hole saw according to the first embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows a side view of the hole saw 1 according to the first embodiment. In the following, the direction in which the cutting edge is located will be referred to as the tip direction (Tip), and the direction opposite to the tip direction will be referred to as the back direction (Back) (see Figures 1 and 2).

As shown in FIG. 1, the hole saw 1 is composed of a shank portion 2 and a blade body portion 4. The blade body portion 4 has a disk-shaped base portion 5, an annular root portion 6 extending from the circumferential edge of the base portion 5 toward the tip, multiple blade portions 7 extending from the root portion 6 toward the tip, a protruding blade portion 11 disposed at the center of the root portion 6 and extending toward the tip, and a groove portion 12 formed in the root portion 6 between the blade portions 7a, 7b adjacent in the circumferential direction. The number and shape of the blade portions 7 are arbitrary.

The base portion 5 has a hole formed in the center, and the tip protrusion 3 of the shank portion 2 is inserted into this hole (see FIG. 3). The tip protrusion 3 has a protruding blade portion 11 attached. The protruding blade portion 11 extends further toward the tip than the blade portion 7. The protruding blade portion 11 is a tapered triangular pyramid. The base portion 6 is cylindrical, and the blade portion 7 is connected to the tip end that extends toward the tip, and a groove portion 12 is formed between the blade portions 7a and 7b. The cutting edge 8 of the blade portion 7 gradually protrudes toward the tip as it moves toward the forward rotation direction (clockwise) of the hole saw 1. Therefore, the forward rotation side end 9 of the blade portion 7 protrudes toward the tip more than the reverse rotation side end 10, and the shape of the cutting edge 8 is an upward incline from the reverse rotation side end 10 toward the forward rotation side end 9. The groove 12 is formed in a U-shape between the end 9 of the blade 7a on the forward rotation side and the end 10 of the blade 7b on the reverse rotation side.

Next, the function and effects of the hole saw 1 will be explained.

When the hole saw 1 is attached to an electric drill (not shown) and rotated, and pressed against a cutting target (not shown) made of metal or resin, a hole is formed in the cutting target. First, the protruding blade portion 11 penetrates the cutting target to form a small hole, and then the periphery of the small hole is cut by the blade portion 9 to form a circular hole. At that time, a circular piece corresponding to the shape of the hole is cut out as cutting waste. The piece is sandwiched between the blade portions 7, but since the protruding blade portion 11 is supported by being passed through the small hole, the piece is separated from the blade portion 7. The piece shifts toward the tip along the tapered shape of the protruding blade portion 11 and comes off the protruding blade portion 11 (if the hole saw 1 is facing downward, the piece falls). Therefore, the piece does not get sandwiched between the blade portions 7.

Next, a hole saw according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows a side view of a hole saw 201 according to the second embodiment, and FIG. 3 shows the tip side of the hole saw 201. Note that the following mainly describes the configuration that differs from the hole saw 1 according to the first embodiment, and a description of the same configuration as the hole saw 1 is omitted.

As shown in Figures 2 and 3, the outer surface of the base portion 206 of the hole saw 201 protrudes outward beyond the cutting edge 207. More specifically, the outer surface of the base portion 206 has a sloped surface 220 and a flange portion 221 connected to the lower portion of the sloped surface 220. The sloped surface 220 is an inclined surface that widens outward toward the rear, which is the opposite side to the tip direction, and is an annular shape that follows the circumferential direction of the base portion 206. The flange portion 221 is an annular shape that protrudes outward beyond the sloped surface 220 below the sloped surface 220 and follows the circumferential direction of the base portion 206.

The groove portion 212 of the base portion 206 has a first groove portion 222 and a second groove portion 223 that curve backward toward the flange portion 221. The first groove portion 222 and the second groove portion 223 are adjacent to each other in the circumferential direction of the base portion 206. The boundary between the first groove portion 222 and the second groove portion 223 is raised toward the tip to form a chamfered blade portion 224. The chamfered blade portion 224 protrudes toward the tip to an extent that does not reach the height of the blade portion 207. Therefore, the chamfered blade portion 224 is located below the blade portion 207. The chamfered blade portion 224 extends from the inside to the outside of the base portion 206, and extends further outward than the blade portion 207. In other words, the base portion 206 is thicker than the blade portion 207 by the amount of the bevel portion 220, and the chamfered blade portion 224 extends across the thickness of the base portion 206, so that the chamfered blade portion 224 reaches further outward than the cutting edge 208.

Next, the function and effect of the hole saw 201 will be explained.

The rotating hole saw 201 is pressed against the cutting object, the blade portion 207 forms a circular hole in the cutting object, and then the chamfering blade portion 224 cuts the edge of the hole. In particular, the chamfering blade portion 224 is formed on the slope portion 220, which smooths the edge of the hole. Thus, the edge of the hole in the cutting object is chamfered. When the flange portion 221 hits the edge of the hole, the movement of the hole saw 201 in the insertion direction relative to the hole is restricted, so that the hole is not chamfered any further. The chamfering blade portion 224 is formed as the boundary between the first groove portion 222 and the second groove portion 223 formed in the groove portion 212, which makes it easy to manufacture.

Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment. Furthermore, various design modifications of the present invention are possible without departing from the scope of the claims.

REFERENCE SIGNS LIST 1, 201 Hole saw 2, 202 Shank portion 3 Tip projection 4, 204 Blade body portion 5, 205 Base portion 6, 206 Base portion 7, 7a-b, 207 Blade portion 8, 208 Blade tip 9 Forward rotation side end 10 Reverse rotation side end 11, 211 Protruding blade portion 12, 212 Groove portion 220 Slope portion 221 Flange portion 222 First groove portion 223 Second groove portion 224 Chamfered blade portion

Claims (5)

A circular root portion;
A plurality of blade portions extending from the base portion toward the tip direction;
A tapered protruding blade portion extending toward a tip end from the blade portion at the center of the base portion;
a groove portion formed in the base portion between the blade portions adjacent in the circumferential direction,
The groove portion is
A chamfering blade portion is formed for chamfering the edge of a hole to be formed in a cutting object.
A hole saw characterized by: The outer surface of the base portion protrudes outward beyond the blade portion,
The chamfered blade portion protrudes toward the tip and extends from the inside to the outside of the base portion .
2. A hole saw according to claim 1. The groove portion is
A first groove portion curved toward the opposite side to the tip direction;
a second groove portion adjacent to the first groove portion in the circumferential direction and curved in the opposite direction to the tip direction,
The chamfering blade portion is protruded toward the tip between the first groove portion and the second groove portion .
3. A hole saw according to claim 2. A slope portion that widens outward toward the opposite side to the tip direction is formed on the outer surface of the base portion .
4. A hole saw according to claim 2 or 3. A flange portion is formed on the outer surface of the base portion below the inclined portion, the flange portion protruding outward from the inclined portion .
5. A hole saw according to claim 4 .

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