JPH0966411A - Hole saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the impact applied to a cutting edge and improve the durability of the cutting edge by setting the projected size of the cutting edge projected from the tip edge of a root metal in a specific range, in a hole saw consisting of a center drill and a root metal having a nearly cylindrical outer periphery wall and mounting the cutting edge on the tip edge of the root metal. SOLUTION: A hole saw for forming a through hole to a material for construction is provided with a center drill 1, a one side open root metal 2 having a nearly cylindrical outer periphery wall 4 and a holder 14 with a shank 3 provided on the base end of this root metal 2. On the outer periphery wall 4 of the root metal 2, slits 5, 5 for wooden chip escape are formed across a prescribed length from the tip edge 7 of the outer periphery wall 4 toward the base end and a cutting edge 8 is provided on the tip of a groove wall 15 in a slit 5 side. In this case, the cutting edge 8 is set to 0.1mm<=H<=0.3mm when the projected size is H. Thereby, it is set so that the cutting edge 8 during rotation may not be cut into a material to be processed excessively and the impact applied to the root metal 2 is reduced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hole saw for forming through holes in a building material.

[0002]

2. Description of the Related Art A center cone is provided with a base metal having a one-sided opening which surrounds the center cone and has a slit on an outer peripheral wall, and a cutting edge provided on a tip edge of the base metal. In the conventional hole saw, as shown in FIG. 6 (a), a cutting edge 41 provided at the tip of the inclined tip edge 40a of the base metal 40.
Of the cutting edge 41 protruding from the tip end portion 42 of the base metal 40 and the tip end portion 42 of the base metal 40 shown in (b).
The projecting dimension from 40b was set to be relatively large (0.5 mm to 1.0 mm). Then, this hole saw was chucked to an electric drill, and a worker bored a hole for wiring (with a hole saw) on a wood pillar or a wood beam at a construction site.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
When a hole is punched from below in the upper beam with a conventional hole saw with a large protruding dimension of 0.5 mm to 1.0 mm as described above, the initial biting of the cutting edge 41 is rapid, so the base metal 40 shakes and It was difficult for the operator to bite into it, the worker could not work smoothly, and there was a danger because it was a work at a high position by climbing on a stepladder. Furthermore, when a metal plate is stretched on the back side of a beam or wall material of wood, when a hole is made there, when the cutting edge 41 reaches the metal plate on the back side, it suddenly bites and shocks the cutting edge. Sometimes 41 was cut.

Therefore, the present invention solves the above-mentioned problems,
An object of the present invention is to provide a hole saw that improves the workability by safely and smoothly forming a hole in a wood beam or a metal plate stretched on the back side of the beam at a construction site.

[0005]

In order to achieve the above-mentioned object, a hole saw according to the present invention has a center cone and a substantially cylindrical outer peripheral wall that surrounds the center cone and has an opening shape. In a hole saw provided with a base metal having a slit in the wall and a cutting edge arranged at the front edge of the base metal, the protruding dimension of the cutting edge protruding from the front edge of the base metal is set to H. At this time, 0.1 mm ≦ H ≦ 0.3 mm was set.

A notch is formed in the vicinity of the tip of the slit, and the width of the groove at the tip of the slit is set to a size that a human finger can enter. When the length dimension of the notch in the longitudinal direction is L, 10 mm ≦ L ≦ 20 mm is set. Further, when the groove width dimension of the slit having the cutout portion is W, 10 mm ≦ W ≦ 20 mm is set.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments.

FIG. 1 shows an embodiment of a hole saw according to the present invention. This hole saw has a center cone 1, a base 2 having a substantially cylindrical outer peripheral wall 4, and an open base metal 2, and the base metal 2. Holder 14 with shank 3 attached to the base end of
It has.

A holder 14 is screwed to the base end of the base metal 2, and an insertion hole 11 for inserting the center cone 1 is formed in the holder 14 and the holder 14 is attached. A screw hole for fixing the center cone 1 to a part
12 are penetrated. The center cone 1 inserted into the insertion hole 11 is pressed and fixed by the set screw 13 screwed into the screw hole 12.

The outer peripheral wall 4 of the base metal 2 is provided with slits 5 and 5 for removing wood scraps from the tip edge 7 of the outer peripheral wall 4 in a base end direction over a predetermined length--almost the entire length. Has been formed. Further, the slit 5 has a gentle curve from the tip edge 7 toward the downstream side in the rotational direction, and has a shape that allows wood dust to be easily discharged to the outside.

Further, as shown in FIGS. 1 and 2, a cutting edge 8 (for example, by brazing a cemented carbide tip) is provided at the tip of the groove wall 15 on one side of the slit 5 (see FIG. 4). The cutting edge 8 is an angle formed by the groove wall surface 17 of the cutting edge 8 and the shaft center 30,
That is, while having a scooping angle α, the upper end surface of the cutting edge 8
It has an angle formed by 16 and the edge 7 of the base metal 2, that is, a clearance angle γ. Further, the cutting edge 8 has an outer surface 18 of the cutting edge 8.
Has a slightly inclined angle with respect to the outer peripheral wall 4, that is, a back taper, so that the outer peripheral wall 4 does not contact the inner surface of the hole to be machined.

As shown in FIG. 2, the tip edge 7 of the base metal 2 is at the tip edge of the tip wall portion 10 provided near the tip of the base metal 2.
That is, in the case of the conventional hole saw, as shown in (a) and (b) of FIG. 6, 40a and 40b were the leading edges (of the base metal 40). By providing the tip wall portion 10 (on the tip edges 40a and 40b thereof), the protruding dimension of the cutting edge 8 tip portion 9 is shortened.

When the above-mentioned protruding dimension of the cutting edge 8 is H, 0.1 mm≤H≤0.3 mm is set.

By setting the above-mentioned protruding dimension H in the above range, the rotating cutting edge 8 is prevented from excessively cutting into the workpiece. Therefore, the impact applied to the base metal 2 is reduced, and the vibration is shaken in the lateral direction with respect to the shaft center.
It is possible to prevent damage to the cutting edge 8 as well as to eliminate.

It should be noted that if the protruding dimension H is less than 0.1 mm, the cutting ability is deteriorated, and if it exceeds 0.3 mm (as described above), the vibration of the base metal 2 becomes large and the cutting edge 8 is damaged. is there.

In FIGS. 1 and 4, a notch 6 is provided in the vicinity of the tip of the groove wall 15 on the other side of the slit 5, and the groove width dimension of the tip of the slit 5 is large enough to accommodate a human finger 38. Is set.

At this time, as shown in FIG. 3, the notch 6
When the length in the longitudinal direction is L, set 10 mm ≦ L ≦ 20 mm. Further, when the groove width dimension of the slit 5 having the notch 6 is W, 10 mm ≦ W ≦ 20 mm is set. As a result, after the through hole is formed as shown in FIG. 4, the work material fitted into the base metal 2 that is cut out into a cylindrical shape by the center cone 1 and the cutting edge 8 is taken out by inserting a finger into the slit 5. It will be easier. Further, since the width of the notch 6 is large only near the tip of the slit 5, the strength of the outer peripheral wall 4 can be maintained.

The length dimension L and the groove width dimension W are 10
If it is less than mm, since the (human) finger 38 does not enter the slit 5, it is fitted into the base metal 2 after the punching work (of the work piece cut out by the center cone 1 and the cutting edge 8). Piece of wood
I can't take 35 out easily. On the other hand, if it exceeds 20 mm, the strength of the base metal 2 will be insufficient and the base metal 2 will be deformed.

At the construction site shown in FIG. 5, however, 26
The beam 27 is a beam, and the beam 27 is provided with a thin metal plate 28 on the upper surface (back surface) side thereof. The hole saw of the present invention (chucked to the electric drill 43) is used to penetrate the vertical hole 25 for wiring (such as a cable or electric wire) from below the beam 27.

Since the vertical hole 25 is provided at a high position near the ceiling, the worker 33 works by climbing on the stepladder 32 or the like. Then, the posture is adjusted and the vertical hole 25 is provided through the beam 27. At this time, the protruding dimension of the cutting edge 8 from the tip edge 7 is 0.1 mm to 0.3
Since it is as small as mm, it does not rapidly cut into the work material (especially the metal thin plate 28) and cuts thinly so that the cutting edge 8 (base metal 2) rotates smoothly and vibration (of the base metal 2) is reduced. To do.
Therefore, the worker 33 can maintain the posture and perform the cutting work safely and smoothly.

[0021]

Since the present invention is configured as described above,
The following effects are obtained.

(According to the hole saw according to the first aspect), the durability of the cutting edge 8 is improved. Also, cutting edge 8 during cutting work
Does not rapidly cut into the work material, the impact on the cutting edge 8 is reduced, and the vibration of the base metal 2 is eliminated.
Even if 33 holds the electric drill 43 with one hand, it can maintain its position and work safely. Further, the metal thin plate 28 can be cut as it is (immediately) after the hole of the beam 27 is cut and drilled, and the work efficiency is improved.

The cylindrical wood piece 35 cut out in the base metal 2 (according to the hole saw according to claim 2, 3 or 4) can be easily pulled out by the finger 38. Therefore, when the vertical holes 25 ... Are pierced at a plurality of places, the work efficiency is improved, which is convenient.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of a base metal.

FIG. 3 is an explanatory diagram showing dimensions of slits.

FIG. 4 is a plan view of a base metal.

FIG. 5 is an explanatory diagram showing a working state.

FIG. 6 is an explanatory view of a main part showing a conventional example.

[Explanation of symbols]

 1 Center cone 2 Base metal 4 Outer peripheral wall 5 Slit 6 Notch portion 7 Tip edge 8 Cutting edge

Claims (4)

[Claims] 1. A base 2 having a center cone 1 and a substantially cylindrical outer peripheral wall 4 that surrounds the center cone 1 and has one opening, and a slit 5 on the outer peripheral wall 4, and the base 2
In a hole saw provided with a cutting edge 8 disposed on the tip edge 7 of the base metal, when the protruding dimension of the cutting edge 8 protruding from the tip edge 7 of the base metal 2 is H, 0.1 mm ≦ H ≦ Hole saw characterized by being set to 0.3 mm. 2. The hole saw according to claim 1, wherein a notch portion 6 is formed in the vicinity of the tip of the slit 5 and the groove width dimension of the tip of the slit 5 is set so that a human finger can be inserted therein. 3. The hole saw according to claim 2, wherein when the length dimension of the notch 6 in the longitudinal direction is L, 10 mm ≦ L ≦ 20 mm is set. 4. The hole saw according to claim 2, wherein when the groove width dimension of the slit 5 having the notch portion 6 is W, 10 mm ≦ W ≦ 20 mm is set.