WO2008117937A1

WO2008117937A1 - A drill

Info

Publication number: WO2008117937A1
Application number: PCT/KR2008/000981
Authority: WO
Inventors: Chong Kuk Yi
Original assignee: Chong Kuk Yi
Priority date: 2007-03-26
Filing date: 2008-02-20
Publication date: 2008-10-02

Abstract

A drill is disclosed. The drill of the present invention includes a body (2), which has a twisted shape and forms a hole in a piece of metal using rotation, and a shank (3), which is integrated with one end of the body. The shank is coupled to a chuck of a drilling machine to receive rotating force from the drilling machine. The shank comprises three rounded portions (5) and three linear portions (4), which are alternately formed around the shank in a predetermined range from the end of the shank towards the body, thus having a triangular cross-sectional shape. Therefore, the drill of the present invention can prevent the shank from slipping with respect to the chuck even when the drill is rotated at a relatively high speed, thus increasing processing accuracy and increasing the lifetime of the drill and the chuck.

Description

[DESCRIPTION] [Invention Title]

A DRILL [Technical Field]

The present invention relates, in general, to drills, which form holes in metal using rotation thereof and, more particularly, to a drill, which has an improved structure to prevent a shank, which is coupled to a chuck, from slipping with respect to the chuck when rotating. [Background Art]

Generally, as shown in Fig. 1, a drill 11 for forming a hole in a piece of metal includes a body 12, which has a twisted shape, and a shank 13, which is integrated with the body 12.

The shank 13 is coupled to a chuck of a drilling machine (not shown) or the like, and the body 12, having a twisted shape receives rotating force from the chuck through the shank 13 and forms a hole, having a predetermined diameter, in the metal substance.

In such a typical drill, in addition to the body for drilling, a shank, which is coupled to a chuck, is one of the important factors of the drill.

The reason for this is that, if the shank, which is coupled to the chuck, idles with respect to the chuck, in other words, if a slippage phenomenon occurs, the accuracy of the operation of drilling the metal substance is reduced, and the lifetimes of the drill and the chuck are reduced.

Therefore, to prevent the shank from slipping with respect to the chuck, when coupling the shank to the chuck, a user must apply relatively strong force to a chuck handle to firmly fasten the shank to the chuck, or, alternatively, a separate subsidiary handle must be welded to the chuck handle to enable the user to apply larger force to the chuck handle such that the coupling between the shank and the chuck can be reliably maintained.

However, in the coupling between the shank of the drill and the chuck, the application of excessive force to the chuck handle induces problems in that a gear of the chuck is badly worn and the chuck handle may be bent.

In addition, when separating the shank from the chuck, relatively large force is required. Therefore, there is a disadvantage in that work efficiency is markedly reduced.

In an effort to overcome these problems, keyless chucks, which are constructed such that, as the speed of revolution increases, the force with which the chuck tightens around the shank is increased, or collet chucks for increasing processing accuracy have been used. However, there is a disadvantage in that, because the keyless chucks and the collet chucks are very expensive, the working expense is increased.

In addition, in the case of the collet chucks, because collect chucks having various diameters must be prepared and time for coupling the collet chuck to a drilling machine or for removing it therefrom is thus required, the working time and expenses are increased.

To solve these problems, a drill having an improved structure was proposed in Korean Utility Model Application No. 20-2005-0024262, which was filed by the applicant of the present invention.

In the drill disclosed by the applicant of the present invention, a shank has a hexagonal cross-section, so that a slippage phenomenon can be prevented. However, in the case where the drill is coupled to a collet chuck, because corners of the hexagonal cross-section interfere with a spring hole formed in the collet chuck, there is a probability of damage to the collet chuck.

As such, this drill cannot be used with a collet chuck, that is, it is problematic in that compatibility is poor. [Disclosure] [Technical Problem]

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a drill, which is configured such that a shank comprises rounded portions and linear portions on the outer surface thereof and thus has a rounded triangular cross-sectional shape, so that, when the drill is coupled to any kind of typical chuck, a slippage phenomenon is prevented upon rotation, thus enhancing the processing accuracy of the operation of drilling a piece of metal, and preventing reductions in the lifetime and accuracy of the drill and the chuck, and which does not require an expensive chuck, thus reducing the working expense.

Another object of the present invention is to provide a drill, which solves the problem of a hexagonal drill disclosed by the applicant of the present invention, that is, a problem of a reduced compatibility with a collet chuck. [Technical Solution]

In order to accomplish the above objects, the present invention provides a drill, including: a body to form a hole in a metal, the body having a twisted shape; and a shank integrated with an end of the body, the shank being coupled to a chuck of a drilling machine to receive a rotating force from the drilling machine, the shank comprising three rounded portions and three linear portions, which are alternately formed around the shank in a predetermined range from an end of the shank towards the body, the shank thus having a triangular cross-sectional shape.

Preferably, the drill may further include an anti-slip surface formed on each of the linear portions of the shank by knurling. [Advantageous Effects]

In a drill according to the present invention, a shank to be coupled to a chuck has rounded portions and linear portions, which are alternately formed on the outer surface thereof, to thus have a rounded polygonal cross- sectional shape, for example, a rounded triangular cross-sectional shape, thus preventing the shank from slipping with respect to the chuck.

Therefore, because the slippage phenomenon is prevented even when the drill is rotated at high speed, the operation of drilling a piece of metal can be stably conducted, the lifetimes of the drill and the chuck are increased, and high accuracy of the drilling operation is ensured. Furthermore, thanks to the rounded portions, when the shank is coupled to the chuck, the shank is prevented from interfering with a spring hole in a collet chuck, thus enhancing compatibility. [Description of Drawings]

Fig. 1 is a perspective view illustrating a typical drill;

Fig. 2 is a perspective view of a drill according to the present invention;

Fig.3 is a plan view of Fig. 2; and

Fig. 4 is a perspective view illustrating another embodiment of the present invention. description of the elements in the drawings> l: drill

2: (twist-shaped) body

3'• shank

4: linear portion

5: rounded portion

10: anti-slip surface [Best Mode]

The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

Fig. 2 is a perspective view of a drill according to the present invention. Fig. 3 is a plan view of Fig. 2. Fig. 4 is a perspective view showing another embodiment of the present invention.

As shown in the drawings, the drill 1 according to the present invention includes a body 2 and a shank 3.

The body 2 has a twisted shape to ensure superior cutting performance and serves to form a hole in a piece of metal using high-speed rotation.

The shank 3 is integrated with the body 2. The shank 3 is fastened to a chuck of a drilling machine or the like so that rotating force is transmitted from the drilling machine to the shank 3 to enable the body 2 to form a hole in the metal substance.

In the present invention, the shank 3 has a rounded polygonal cross- section, for example, a rounded triangular cross-section, to prevent the shank 3 from slipping with respect to the chuck. For this, on the portion of the shank 3 that comes into contact with the chuck, in a predetermined range from the end of the shank 3 towards the body, several, for example, as shown in the drawings, three rounded portions 5 and three linear portions 4 are alternately formed, thus forming a rounded polygon, that is, a rounded triangular cross-sectional shape.

Meanwhile, as such, although the drill, which is coupled to the chuck of the drilling machine, can be prevented from undesirably slipping with respect to the chuck merely by the structure in which the shank 3 has the rounded triangular cross-sectional shape formed by the rounded portions 5 and the linear portions 4, it is more preferable that an anti-slip surface 10 be formed on the outer surface of the shank 3, in detail, on each linear portion 4, through a knurling process, thus further increasing an anti-slip effect.

In the drill according to the present invention having the above- mentioned structure, after the shank 3, which has the rounded triangular cross-sectional shape formed by the rounded portions 5 and the linear portions 4, is fastened to the chuck of the drilling machine, even when the chuck is rotated at a high speed, the shank 3 is prevented from undesirably slipping with respect to the chuck.

Therefore, the body 2 can very stably conduct an operation of drilling the metal substance. As well, there are advantages in that the lifetimes of the drill and the chuck are increased, and in that the high accuracy of the drilling operation is ensured.

Moreover, the present invention can overcome the problem of the conventional hexagonal drill, a patent application for which was filed by the applicant of the present invention, that is, the problem of interference with a spring hole in a collet chuck is overcome, thus enhancing compatibility.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[CLAIMS] [Claim 1]

A drill , comprising: a body to form a hole in a metal, the body having a twisted shape; and a shank integrated with an end of the body, the shank being coupled to a chuck of a drilling machine to receive a rotating force from the drilling machine, the shank comprising three rounded portions and three linear portions, which are alternately formed around the shank in a predetermined range from an end of the shank towards the body, the shank thus having a triangular cross-sectional shape. [Claim 2]

The drill according to claim 1, further comprising: an anti-slip surface formed on each of the linear portions of the shank by knurling.