JP2001287220A - Drill bit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drill bit which is imparted with excellent characteristics. SOLUTION: A drill bit, the frame of which comprises a front section (3) with protrusions (7) is provided. A set of the first rear teeth (9) is arranged at the front section (3), preferably at the rear part of the protrusions (7). The set of the first rear teeth (9) broadens a drilled hole when the drill is reversed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill bit whose frame has a front portion with a projection.

[0002]

2. Description of the Prior Art A typical drill bit has a cylindrical frame with a front portion, the diameter of the front portion being larger than the diameter of other portions of the frame. Such drill bits are not guided properly. For example, if the drill bit is
When striking hard rock diagonally, the drill bit moves easily in the lateral direction and becomes immobile at the edge of the drilled hole. Furthermore, if such a drill bit is used, it is difficult to reverse the drill bit, i.e. withdraw the drill from the hole. Reversal is particularly difficult when drilling a bank, for example when the object to be drilled is clay or a similar soft material and / or clastic rock.

[0003] A drill bit for bank drilling is disclosed, wherein the diameter of the drill bit is substantially the same both at the front of the drill bit and elsewhere in the drill bit. Further, the rear teeth, ie, the rear reamer, are provided at the rear edge of the drill bit. The purpose of the rear reamer is to enlarge the drilled hole when the drill is reversed. However, reversal is not always easy because the material removed from the edge of the hole by the rear reamer blocks the area between the rear and the front of the drill bit in a relatively simple manner.

[0004]

It is an object of the present invention to provide a drill bit having excellent characteristics.

[0005]

A drill bit according to the present invention is characterized in that a rear tooth is provided in association with a front part.

An essential idea of the invention is that a first set of rear teeth is provided on the drill bit in relation to the front of the drill bit. The idea of a preferred embodiment of the invention is that the projections are present in relation to the front such that the diameter measured at the projections is greater than the diameter of the middle part of the drill bit frame, and the projections also ,
The diameter of the rear part of the drill bit measured at these projections is greater than the diameter of the middle part of the drill bit frame. The idea of another preferred embodiment is that the diameter of the back of the drill bit measured at the protrusion is smaller than the diameter of the front of the drill bit measured at the protrusion. The idea of the third preferred embodiment is that the second set of rear teeth is provided on the rear projection of the drill bit.

The present invention provides the advantage that the drill and the drill bit can be completely smoothly reversed and that the gap between the drill bit and the hole does not easily close. By providing the projection at the rear of the drill bit, the drill bit is guided efficiently. By making the rear projections smaller than the front projections, guidance is improved and the gap between the rear part of the drill bit and the hole is substantially unobstructed during drilling and reversing operations. If the second set of rear teeth is provided on the rear projection, the rear second set of rear teeth is
During reversal, a pilot reamer action is performed, with the first set of rear teeth at the front of the drill bit performing a virtual drilling operation. This means that the reamer operation is performed in two stages, and the reverse operation is performed very smoothly and easily.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 shows a drill bit 1. If this drill bit is used, it is attached to one end of a drill rod, for example, in a thread 2 or other known manner. Drill bit 1 consists of front part 3 and middle part 4
And a rear part 5. A hard metal button 6 is provided on the face of the drill bit frame in a known manner. Most preferably, each hard metal button 6 is secured over its own bulge in the manner shown in FIG. 2, in which case the flushing fluid can be very efficiently placed between the hard metal button 6 and the bulge. And it can flow easily.
The protrusions 7 are formed on the front part 3 such that the diameter of all three measured at the protrusions is larger than the diameter of the intermediate part 4. The drill bit 1 further comprises a plurality of openings 8 through which flush fluid can flow.

The first set of rear teeth 9 is formed at the front part 3 at the rear edge of the projection 7. The first rear teeth 9 are inclined as shown in FIG. 1 so that when the drill bit rotates in the direction indicated by arrow A, these teeth are drilled while the drill bit 1 performs the reversing operation. , The reversal can be conveniently performed. Since the first set of rear teeth 9 is present in connection with the front part 3 of the drill bit 1, the material removed by the first set of rear teeth 9 during the reversing operation is drilled with the drill bit 1. It easily escapes beyond the front without closing the gap in the perforated wall. Since the first set of rear teeth 9 is thus associated with the front part 3, the distance between the first set of rear teeth 9 and the face of the drill bit 1 is considerably shorter. The distance between the first set of rear teeth 9 and the face of the drill bit 1 is preferably smaller than the diameter of the front part 3 of the drill bit 1. It is particularly preferred that the distance between the first set of rear teeth 9 and the face of the drill bit 1 is less than 0.5 times the diameter of the front part 3 of the drill bit 1.

A second set of projections 10 is provided at the rear 5 of the drill bit. The second set of projections 10 at the rear 5 improves the guiding of the drill bit 1. However,
The second protrusion 10 of the rear part 5 is located below the protrusion 7 of the front part 3. Thus, the diameter of the rear part 5 measured at the second set of projections 10 is greater than the diameter of the middle part 4 of the drill bit 1 but smaller than the diameter of the drill bit 1 measured at the projection 7. In this case, the gap between the rear part 5 of the drill bit 1 and the wall of the drilled hole is not very easily closed. The second set of rear teeth 11 is provided at the rear end of the projection 10. When the drill bit 1 is actuated in reverse, the second set of rear teeth 11 performs the actuation of the pilot reamer and the first set of rear teeth 9 associated with the front part 3 is actually associated with the front part 3. Functions as a reamer for Reamer operation is 2
It takes place in two stages, whereby the drill bit 1 is smoothly reversed and the risk of obstruction is eliminated.

The drawings and the related description are only intended to illustrate the idea of the invention. The invention varies in its details within the scope of the claims. Thus, the projections between the front part 3, the middle part 4, and the rear part 5 can vary under rather wide limits. Furthermore, the second set of projections 10 is at least partially, for example,
It can extend to the middle part 4. The second projection 10 on the rear part 5 can also be inclined or spiral.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a drill bit of the present invention including a partial cross section.

FIG. 2 is a front view of the drill bit of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... drill bit, 2 ... thread groove, 3 ... front part, 4 ... middle part, 5 ... rear part, 6 ... button, 7 ... protrusion, 8 ... opening, 9 ...
First rear teeth, 10 ... projections.

Claims (6)

[Claims] 1. A drill bit (1) comprising: a drill bit (1);
A rear portion (5) with a second projection (10) provided to improve the guidance of the second projection (10), the rear end of the second projection (10) forming the second set of rear teeth (11). A drill bit, characterized in that the frame has a front part (3) with a projection (7), the front part (3) with the first set of rear teeth (9). 2. The method according to claim 1, wherein the distance between the first rear teeth (9) and the face of the drill bit (1) is smaller than the diameter of the front part (3) of the drill bit (1). The drill bit according to 1. 3. The distance between the first rear teeth (9) and the face of the drill bit (1) is less than 0.5 times the diameter of the front part (3) of the drill bit (1). 3. The drill bit according to claim 2, wherein the drill bit has features. 4. A drill bit according to claim 1, characterized in that the first set of rear teeth (9) is provided at the rear of the projection (7). 5. Drill bit measured at the projection (7)
5. The method according to claim 1, wherein the diameter of (1) is larger than the diameters of other parts of the drill bit (1).
The described drill bit. 6. A drill bit (1) comprising an intermediate part (4) and a rear part.
The point having (5) and the rear part (5) is such that the diameter of the rear part (5) measured in the second set of projections (10) is larger than the diameter of the middle part (4) of the drill bit (1). 6. The method according to claim 1, characterized in that it comprises a second set of projections (10) which are large but smaller than the diameter of the front part (3) of the drill bit (1) measured at the projections (7). The drill bit according to any one of the above.