Disclosed is an insert tip used when steel or cast iron is worked, in which redundant portions are provided inside bolt holes formed in the insert tip to slantingly fit a bolt into the bolt holes, the bolt serving to fix the insert tip to a cutter body, so that more insert tips can be fly fixed to the cutter body.
Generally, an insert tip is an element of a cutter used to work steel or cast iron and is made of cemented carbide. The insert tip is fixed to a cutter body of steel by a bolt and the like, so as to cut a to-be-cut material as a cutter rotates.
Hereinafter, a related art insert tip will briefly be described with reference to
First, the insert tip shown in
The bolt hole 21 is gradually tapered toward the center portion to insert a head portion of the bolt 30 therein.
In this case, the double-edged insert tip 20a may use the cutting edge at the upper surface. Alternatively, the double-edged insert tip 20a may use the cutting edge at the lower surface if it is reversed. Therefore, the inside of the bolt hole 21 is symmetrically formed up and down around its center portion.
The insert tip shown in
Furthermore, since the single-edged insert tip 20b uses only the draw-out line at the upper surface, it does not have to be reversed. Therefore, the inside of the bolt hole 21 is not required to be symmetrically formed up and down, unlike the double-edged insert tip 20a.
In the related art insert tips 20 constructed as above, a wrench (not shown) is inserted into a wrench insertion hole 31 of the bolt 30, and the bolt 30 is rotated to fix the insert tips 20 to the cutter body 10. Then, the cutter is rotated to cut the to-be-cut material.
However, the related art insert tips 20 have several problems. If a to-be-cut material having high hardness, such as steel or cast iron, is worked, the number of insert tips 20 fixed to the cutter is insufficient. For this reason it takes a long working time, and surface roughness is low because of a rough working surface. Moreover, chipping occurs in the cutting edge provided at each corner portion of the insert tips.
Furthermore, a cutting force F in a rotational direction and a reaction force F1 corresponding to the cutting force F act on the related art insert tips 20. The reaction force F1 is supported by only a fitting force F2 of the bolt 30 that secures the insert tips 20 to the cutter body 10. In this case, it is difficult to obtain the sufficient fitting force. As a result, the insert tips 20 fail to be firmly fixed to the cutter body 10 because of the insufficient fitting force.
As described above, if the insert tip is not firmly fixed to the cutter body 10, stress is concentrated on one side of the insert tip 20. For this reason, the insert tip 20 may be damaged during working process.
Accordingly, an object of the present invention is to provide an insert tip for a cutter in which the insert tip is firmly fixed to a cutter body using only a fitting force of a bolt, working time of a to-be-cut material is short, and surface roughness is high.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Hereinafter, an insert tip according to the embodiment of the present invention will be described in detail with reference to
The insert tip shown in
A bolt hole 210 is formed at a center area of the double-edged insert tip 200a, and communicates upper and lower surfaces of the double-edged insert tip with each other to receive a bolt 300 therein, which fixes the double-edged insert tip 200a to the cutter body 100.
A clearance portion 211 is formed at an inner side of the bolt hole 210 so that the bolt 300 can be fitted into the bolt hole 210 at a predetermined slant toward the cutter body 100 based on a vertical line of the cutter body 100 that adjoins the bottom of the double-edged insert tip 200a.
As shown in
Further, since double-edged insert tip 200a may use either the cutting edge at the surface or the cutting edge at the lower surface, the inside of the bolt hole 210 is preferably formed to make a symmetrical shape up and down around its center portion.
In the double-edged insert tip 200a according to the embodiment of the present invention, the bolt 300 is fitted to the cutter body 10 at a predetermined slant angle α from one corner portion of the double-edged insert tip 200a to its opposite corner portion, wherein the double-edged insert tip 200a cuts the to-be-cut material in a state that interference between the bolt 300 and the bolt hole 210 is avoided. In this case, since the portion of the cutter body 100 required to fit the bolt 300 is reduced, the number of double-edged insert tips 200a more than the number of the related art double-edged insert tips can be fixed to the cutter having the same diameter as that of the related art cutter.
Furthermore, since the bolt 300 is fitted to the cutter body 100 at a predetermined slant angle α from one corner portion of the double-edge insert tip 200a to its opposite corner portion, wherein the double-edged insert tip 200a cuts the to-be-cut material in a state that interference between the bolt 300 and the bolt 210 is avoided lateral pressure F3 as well as a fitting force F2 in a vertical direction acts on the double-edged insert tip 200 fixed to the cutter body 100 to correspond to a reaction force F1 caused by a cutting force F during cutting working. Therefore, the fitting force between the cutter body 100 and the double-edged insert tip 200a is increased.
Particularly, if the angle α of the bolt 300 fitted into the cutter body 100 is less than 8° the lateral pressure F3 acting on the double-edged insert tip 200a becomes too weak. If the angle α of the bolt 300 fitted into the cutter body 100 is greater than 20° the fitting force F2 in a vertical direction acting on the double-edged insert tip 200a becomes insufficient, thereby resulting in that the double-edged insert tip 200a fails to be firmly fixed to the cutter body 100. Therefore, the clearance portion 211 is preferably recessed at each corner portion of the inner sides of the bolt hole 210 so that the slant angle α of the bolt 300 is in the range of 8° to 20°.
Meanwhile, as another example of the insert tip according to the present invention, the redundant portion may be formed only at the lower portion of the insert tip.
In other words, since a single-edged insert tip 200b shown in
In this case, the clearance portion 221 is formed so that the bolt 300 is fitted at a predetermined slant angle α toward the cutter body 100 based on the vertical line of the cutter body 100 adjoining the bottom of the single-edged insert tip 200b. The angle α is preferably in the range of 8° to 20°.
The aforementioned insert tip 200 of the present invention is inserted into a wrench insertion hole 310 formed at a head portion of the bolt 300, and the bolt 300 is rotated to fix the insert tip 200 to the cutter body 100. Then, the cutter is rotated to cut the to-be-cut material (not shown).
In the present invention, the clearance portion 211 and 221 are formed in the bolt holes 210 and 220 of the insert tip 200 so that the bolt 300 is to be fitted to the cutter body 100 at a predetermined slant angle α. In this case, since the portion of the cutter body 100 required to fit the bolt 300 is reduced, the number of the insert tips 200 more than the number of the related art insert tips can be fixed to the cutter having the same diameter as that of the related art cutter. Also, the fitting force between the cutter body 100 and the insert tip 200 can be enhanced.
In addition since the bolt 300 is fitted into the cutter body 100 through the clearance portions 211 and 221, it is possible to exactly determine the position where the insert tip 200 is fixed to the cutter body 100.
An insert tip of the present invention has the following advantages. Since the bolt that fixes the insert tip to the cutter body is slantingly fitted to the cutter body and the bolt is slantingly received in the bolt hole formed in the insert tip, the number of the insert tips more than the number of the related art insert tips can be fixed to the cutter having the same diameter as that of the related art cutter. In this case, the time required to work the to-be-cut material is reduced to improve the productivity. Since the working surface of the to-be-cut material is even, the surface roughness is improved and chipping can be prevented from occurring in the cutting edge of the insert tip.
Further, since the lateral pressure is additionally provided to correspond to the reaction force acting on the insert tip when the insert tip is fixed to the cutter body, the fitting force against the cutting force can sufficiently be obtained. As a result, the insert tip can more firmly be fixed to the cutter body and can be prevented from being damaged.
Finally, since the bolt is fitted to the cutter body through the redundant portions, the position of the insert tip can easily be determined.
cutter, insert tip, bolt, bolt hole, redundant portion
Number | Date | Country | Kind |
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10-2004-0093516 | Nov 2004 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/KR2005/002878 | 8/31/2005 | WO | 00 | 3/28/2008 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2006/054824 | 5/26/2006 | WO | A |
Number | Name | Date | Kind |
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6579042 | Shiraiwa | Jun 2003 | B1 |
7021871 | Arvidsson et al. | Apr 2006 | B2 |
20040223819 | Sheffler et al. | Nov 2004 | A1 |
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1 197 281 | Apr 2002 | EP |
1 385 251 | Feb 1975 | GB |
46-2897 | Oct 1971 | JP |
5-49203 | Jun 1993 | JP |
03 022495 | Mar 2003 | WO |
Number | Date | Country | |
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20080193233 A1 | Aug 2008 | US |