JPH10146709A - Two-stage boring countersink drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly set even a boring depth without losing a rotational balance by pushing a set screw screw-fitted toward an intermediate hole to a connecting body against a center drill by penetrating through a female screw hole arranged in a drill edge body, and fixing the center drill, the drill edge body and the connecting body together. SOLUTION: A general purpose drill is used as a center drill 1, and in a drill edge body 2, a cutting edge 2a is arranged in an end part, and the center drill 1 is penetratingly inserted into a through hole arranged in the center so that a position can be freely moved. In a connecting body 3, a shank 5 is formed in an upper part, and an opening intermediate hole 6 is arranged in a lower end surface, and the drill edge body 2 where the center drill 1 is penetratingly inserted into the intermediate hole 6 is fitted and inserted so that a downward projecting length can be freely adjusted. A set screw 4 is screw-fitted toward the center to the connecting body 3, and is screw fitted to a female screw hole 7 continuously arranged in the drill edge body 2, and is pushed against a center drill peripheral surface in the drill edge body 2, and the center drill 1, the drill edge body 2 and the connecting body 3 and fixed together. The shank 5 is installed in a chuck of a rotational driving shaft, and a hole is bored.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling machine for drilling a small hole through which a fastener such as a bolt is inserted, and simultaneously forming a large-diameter hole for embedding a head of the fastener into a predetermined depth. The present invention relates to a two-stage drilling conical cone that is simultaneously ground.

[0002]

2. Description of the Related Art As a countersunk cone for two-stage drilling, it is known to use a general-purpose drill as a center drill, and to attach a conical blade to the center drill so that the position can be changed.

[0003] For example, as a countersink for this type of two-stage drilling,
At the lower end, leaving a base portion, a chip discharge groove is cut in a notch shape, and a cutting edge is provided at the groove edge to form a conical blade body. There is a configuration in which the two are fixed by a set screw screwed into the connector.

In the use of the two-stage drilling conical cone having such a configuration, the base (upper end) of the center drill projecting above the cone blade is attached to a chuck provided on a rotary drive shaft of the drilling machine. In the process of drilling a small hole by a center drill, a large-diameter hole is continuously cut by a conical blade.

However, in the above-described conventional two-stage drilling countersink, a center drill having a large mass is mounted on the center drill, and the center drill is protruded above the center drill. Since the base is attached to the chuck of the rotary drive shaft and drilling is performed, a relatively small center drill requires a greater load to attach to the chuck of the rotary drive shaft compared to drilling with the center drill alone. The load is increased, the rotational balance is easily lost, the workability is degraded due to wobbling, etc., and the center drill may be bent between the chuck and the conical blade.

Further, even if the sharpness of the cutting edge of the cone blade is reduced, the cutting efficiency cannot be sharpened depending on the work site, which also affects the work efficiency.

Further, since there is no means for setting the drilling depth, that is, the shaving depth of the large-diameter hole, the shaving depth of the large-diameter hole by the conical blade is limited. It depends greatly on the skill (intuition) of the operator, and lacks uniformity when drilling a large number of holes.

[0008]

SUMMARY OF THE INVENTION Therefore, according to the present invention, a conical blade is fixed together with a center drill to a connecting body by using a set screw, and a shank formed in the connecting body is chucked on a rotary drive shaft. By attaching to the center drill, a counter drill for two-stage drilling that eliminates the load burden of the center drill and does not break the rotational balance, and can also set the depth of drilling by the center drill and the cone blade properly The purpose is to provide.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a conical body having a center drill penetrated therein and a shank formed on an upper portion thereof. Through a female hole provided in the conical blade body, and push a set screw screwed into the coupling body toward the central hole through the female screw hole provided in the conical blade body, thereby pressing the center drill and the conical blade. It is characterized in that the body and the connected body are fixed.

[0010] Here, it is preferable that the conical blade body is provided with cutting blades at both ends of the conical blade body, and a set screw screwed to the connecting body, and the set screw. Regarding the relationship between the number of female screw holes provided in the conical blade body corresponding to the above, the number of female screw holes is preferably greater than the number of set screws.

It is preferable that a screw pressing plane on which the set screw is pressed is formed on the peripheral surface of the center drill corresponding to the set screw screwed to the connecting body.
As described in claim 4, it is effective to displace the position in the axial direction and to form it in a backward direction.

In the two-stage drilling conical cone configured as described above, if the sharpness of one of the cutting edges of the cone blade is reduced at the time of drilling, the set screw is loosened at the work site and the cone blade is turned in the opposite direction. Since the other cutting blade can be used, the working efficiency is not reduced.

When the set screw is loosened and the length of the protruding portion of the conical blade body with respect to the connecting body is changed and fixed, the cutting depth of the large-diameter hole by the conical blade body can be changed.

When the center drill is fixed by pressing the set screw against the corresponding screw pressing plane, the center drill can be firmly fixed without any positional deviation, especially in the rotational direction.

Further, when the set screw is loosened and the set screw is pressed and fixed by selectively using a screw pressing plane provided in a rearward direction, the length of the center drill projecting from the conical blade body is gradually reduced. The depth of the small hole by the center drill can also be changed.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a center drill, 2 denotes a conical blade, 3 denotes a connecting body, and 4 denotes a set screw. Show.

As the center drill 1, a general-purpose drill is used. The conical blade body 2 is provided with a cutting blade 2a at an end, and a center drill 1 is movably inserted into a through hole provided at the center. The connecting body 3 is provided with a shank 5 at an upper part thereof and a bore 6 opened at a lower end face thereof. The conical blade body 2 having the center drill 1 inserted through the bore 6 is moved downward. The protruding length is inserted so as to be adjustable. The set screw 4 is screwed toward the center of the connecting body 3 toward the center thereof, and is continuously screwed from the connecting body 3 into a female screw hole 7 provided in the conical blade body 2 so as to be screwed into the peripheral surface of the center drill in the conical blade body 2. This is to fix the center drill 1, the cone blade 2 and the connecting body 3 by pressing.

In the embodiment, the cutting blade 2 of the cone 2
a are provided at both ends thereof, and when drilling, one of the cutting blades 2a
When the sharpness of the cutting edge is reduced, the set screw 4 is loosened and the conical blade body 2 is turned in the opposite direction, so that the other cutting edge 2a can be used. Further, two setscrews 4 screwed to the connecting body 3 are provided apart from each other in the axial direction, and the cone blade body 2 corresponding to the two setscrews 4 has one set screw from the number of set screws. A large number of three female screw holes 7 are provided, and the set screw 4 is loosened to move the position of the conical blade 2 with respect to the connecting body 3 so that two of the three female screw holes 7 are selectively provided. , The length of projection of the conical blade body 2 below the connecting body 3, that is, the cutting depth of the large-diameter hole by the conical blade body 2 can be changed stepwise.

Further, in the embodiment, a screw pressing plane 8 against which the set screw 4 is pressed is provided on the peripheral surface of the center drill corresponding to the set screw 4 screwed to the connecting body 3. The screw pressing plane 8 is formed in a rearward direction (only one side is shown in the drawing) with a slight shift in the axial direction, and the set screw 4 is loosened and provided in the rearward direction. By selectively using one of the screw pressing planes 8, the length of the center drill 1 protruding from the conical blade body 2, that is, the depth of drilling of the small hole by the center drill 1 is also stepwise but small. Make changes possible.

In the embodiment, a total of four setscrews 4 opposed to each other are used as the set screws 4 screwed from the connecting body 3 into the female screw holes 7 of the conical blade body 2. Effectively pressed against the screw pressing plane 8 of the drill 1 and fixed are two of the set screws 4,
The set screws 4 are used to assist in fixing the center drill 1.

[0021]

The present invention is embodied in the form described above, and according to the present invention, the chuck of the rotary drive shaft is provided with:
Since the shank formed on the connecting body is attached and drilled,
There is no such thing as losing rotation balance and perturbing when drilling.

Further, the center drill is fixed to the connecting body together with the cone blade, and the center drill is used only for drilling at a portion protruding below the cone blade, so that the load for attaching to the chuck at the time of drilling. The burden is eliminated and the center drill from this side does not bend.

When the sharpness of one of the cutting blades is reduced, the set screw can be loosened at the work site so that the conical blade can be turned in the opposite direction and the other cutting blade can be used for drilling. There is no decrease in efficiency.

Further, the set screw can be loosened to change the fixing position of the conical blade with respect to the connected body to change the shaving depth of the large-diameter hole by the conical blade. The length of the center drill projecting from the conical blade can be changed in small increments by selectively using the screw pressing plane provided in the hole, and the depth of the small holes by the center drill can also be changed, so that many holes can be made uniform . In addition, the set screw is pressed against the screw pressing plane of the center drill, so that there is no positional shift of the center drill, especially in the rotational direction, and it is firmly fixed and has high stability.

[Brief description of the drawings]

FIG. 1 is a front view showing a part of a two-stage drilling countersunk cone in cross section.

FIG. 2 is an exploded perspective view of a counterbore for two-stage drilling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Center drill 2 Conical blade 3 Connecting body 4 Set screw 5 Shank 6 Medium hole 7 Female screw hole 8 Screw pressing plane

Claims (4)

[Claims] 1. A set screw having a cone drill penetrated through a center drill inserted into a bore formed in a lower end surface of a connecting body having a shank formed thereon and screwed into the connecting body toward the bore. Characterized by penetrating a female screw hole provided in a cone blade body, pressing against a center drill, and fixing the center drill, the cone blade body and the connecting body. 2. The conical cone for two-stage drilling according to claim 1, wherein cutting edges are provided at both ends of the cone blade body. 3. The double-drilled countersunk cone according to claim 1, wherein the number of female screw holes provided in the conical blade is greater than the number of set screws screwed into the connecting member. 4. A screw pressing plane is formed on a peripheral surface of a center drill corresponding to a set screw to be screwed to a connecting body, the position being shifted in an axial direction and facing backward. The countersink for two-stage perforation according to 1, 2, or 3.