Description

CUTTING TOOL WITH AN INCLINED CLAMPING SCREW

Technical Field

[I] The present invention relates to a cutting tool, more particularly, to a cutting tool in which an insert can be rotated to change a cutting edge (or cutting corner) of an insert and an insert can be removed without detaching a clamping screw.

[2]

Background Art [3] In general, a machining tool comprises a holder and a cutting insert fixed to a pocket portion of the holder through a clamping means and contacted with a work-piece. [4] [5] FIG. 1 is a partial plane view of a conventional cutting tool comprising a holder and an insert mounted to the holder. [6] [7] An insert 1 is fixedly mounted in a pocket portion 2A formed on an upper portion of a holder 2 through a clamping screw 3, an cutting edge or a cutting corner (hereinafter, referred to as "cutting portion") of the insert 1 exposed out of the holder 2 is contacted with a work-piece (not shown) to machine the work-piece. [8] [9] As the machining process is performed, the cutting portion of the insert 1 is worn away so that the insert 1 can not machine accurately the work-piece. Accordingly, the user should rotate the insert 1 with respect to the holder 2 to make new cutting portion of the insert 1 correspond to the work-piece. [10]

[I I] To rotate the insert and correspond new cutting portion of the insert 1 to the work- piece, the user detaches completely the clamping screw 2 from the holder 2 and removes the insert 1 from the pocket portion 2A of the holder 2. Then, the user fixes the insert 1 to the holder 2 by means of the clamping screw 3 so that new cutting portion of the insert 1 is protruded out of the holder 2.

[12] There are problems that theses processes for detaching the insert from the holder and re-mounting the insert to the holder are complicated and the user might lose the clamping screw detached from the holder during the process. [13] [14] In addition, the above problem is generated during a process for removing the insert

1 in which all the cutting portions are worn away and mounting new insert to the holder 2.

[15]

Disclosure of Invention

Technical Problem

[16] The present invention is conceived to solve the aforementioned problems which can be generated at the time of changing a cutting edge or cutting corner that is worn away into new cutting edge or cutting corner and replacing an insert with new one. An object of the present invention is to provide a cutting tool having a structure in which an insert can be rotated without detaching completely a clamping screw from a holder to correspond the new cutting edge or cutting corner of the insert to a work-piece to be machined and an insert can be removed from a holder without detaching completely a clamping screw from a holder.

[17]

Technical Solution

[18] A cutting tool according to the present invention comprises a holder consisting of a pocket portion having a side surface and a bottom surface and a clamping hole formed below the pocket portion; an insert having cutting portions and a central through hole and mounted on the pocket portion of the holder; and a clamping screw for securing the insert to the holder, the clamping screw including a head portion contacted with an inner circumference surface of the through hole of the insert and a coupling portion passing through the through hole of the insert and coupled with the clamping hole of the holder.

[19]

[20] Here, the clamping hole of the holder has a central line inclined with an angle with respect to a perpendicular line to the bottom surface of pocket portion, the head portion of the clamping screw consists of an upper cylindrical portion and a lower frustum portion, the through hole of the insert includes a minimal diametral portion and an upper region having a diameter which gradually increases toward the upper end, and the diameter of the upper cylindrical portion of the head portion of the clamping screw is smaller than that of the minimal diametral portion of the through hole of the insert, but a length of a horizontal prolate axis of the head portion of the clamp screw which is inclined with the angle is larger than a diameter of the minimal diametral portion.

[21]

[22] In the cutting tool according to the present invention, the upper cylindrical portion and the lower frustum portion of the head portion of the clamping screw are simultaneously contacted with the upper region of the inner circumference surface of the through hole of the holder.

[24] In the cutting tool according to the present invention, the through hole of the insert can further include a lower region having a diameter which gradually increases toward the lower end, and the coupling portion of the clamping screw has a length larger than a height of the pocket portion of the holder.

[25]

Advantageous Effects

[26] In the cutting tool according to the present invention having the structure and function as described above, the insert can be rotated and correspond new cutting portion (cutting edge or cutting corner) to a work-piece and the insert can be removed from the holder without detaching completely a clamping screw from a holder, and so it is possible to prevent a clamping screw from being lost at the time of changing a cutting portion of an insert and replacing an insert with new one.

[27]

Brief Description of the Drawings

[28] FIG. 1 is a partial plane view of a conventional cutting tool comprising a holder and an insert mounted to the holder.

[29] FIG. 2 is a sectional view of a cutting tool according to the first embodiment of the present invention and corresponds to the view taken along the line A-A in FIG. 1.

[30] FIG. 3 is a view illustrating a state where the insert is rotated with respect to the clamping screw and removed from the holder.

[31] FIG. 4 is a view illustrating a state where the insert is being removed from the holder.

[32] FIG. 5 is a view corresponding to FIG. 2 and shows the cutting tool comprising the clamping screw having a modified shape.

[33]

Best Mode for Carrying Out the Invention

[34] Hereinafter, a cutting tool according to the embodiment of the present invention is described in detail with reference with the accompanying drawings.

[35]

[36] FIG. 2 is a sectional view of a cutting tool according to the embodiment of the present invention and corresponds to the view taken along the line A-A in FIG. 1.

[37]

[38] A cutting tool according to the embodiment of the present invention comprises a holder 20 consisting of a pocket portion 22 having a side surface and a bottom surface and a clamping hole 21 formed below the pocket portion 22; an insert 10 having cutting portions and a central through hole 11 and mounted on the pocket portion 22 of the holder 20; and a clamping screw 30 including a head portion 31 contacted with an inner circumference surface of the through hole 11 of the insert 10 and a coupling

portion 32 passing through the through hole 11 of the insert 10 and coupled with the clamping hole 21 of the holder 20.

[39]

[40] In the cutting tool having the structure as described above, the holder 20 is constituted such that a central line of the clamping hole 21 is inclined with an angle with respect to a perpendicular line to the bottom surface of pocket portion 20.

[41]

[42] The clamping screw 30 is the member used for securing the insert 10 to the holder

20, the head portion 31 contacted with an inner circumference surface of the through hole 11 of the insert 10 consists of an upper cylindrical portion 31-1 and a lower frustum portion 31-2. The lower frustum portion 31-2 has a diameter which gradually decreases toward a lower end, that is, the coupling portion 32.

[43]

[44] The insert 10 has the through hole 11 formed at a central portion thereof, the through hole 11 comprises an upper region 11-1, a lower region 11-2 and a minimal diametral portion 11-3 disposed between the upper region 11-1 and the lower region 11-2. The upper region 11-1 has a diameter which gradually increases toward the upper end, and the lower region 11-2 has a diameter which gradually increases toward the lower end.

[45]

[46] As shown in FIG. 4, on the other hand, it is preferable that the diameter (d) of the upper cylindrical portion 31-1 of the head portion 31 of the clamping screw 30 is smaller than a diameter (D) of the minimal diametral portion 11-3 of the through hole 11 of the insert 10.

[47]

[48] In addition, as shown in FIG. 2, a length (L) of a horizontal prolate axis of the head portion 31 of the clamp screw 30 which is inclined with the angle is larger than a diameter (D) of the minimal diametral portion 11-3 of the through hole 11 of the insert 10.

[49]

[50] In the cutting tool according to the embodiment of the present invention constructed as described above, a process for mounting the insert 10 to the holder 20 is described below.

[51]

[52] To mount the insert 10 to the holder 20 using the clamping screw 30, in a state where the insert 10 is placed on the pocket portion 22 of the holder 20, the coupling portion 32 of the clamping screw 30 passes through the through hole 11 of the insert 10 and is then screw-coupled with the clamping hole 21 of the holder 20.

[53]

[54] As shown in FIG. 2, at this time, due to a relation between the insert 10 placed horizontally on the pocket portion 22 of the holder 20 and the clamping screw 30 inclined with an angle with respect to the surface of the pocket portion 22 of the holder 20, a length (L) of a horizontal prolate axis of the head portion 31 of the clamp screw 30 is larger than a diameter (D) of the minimal diametral portion 11-3 of the through hole 11 of the insert 10 and the upper cylindrical portion 31-1 and the lower frustum portion 31-2 of the head portion 31 of the clamping screw 30 are simultaneously contacted with the inclined upper region 11-lof the inner circumference surface of the through hole 11 of the insert 10. Accordingly, the insert 10 is securely mounted to the holder 20 through the clamping screw 30.

[55]

[56] In the meantime, during the above process for mounting the insert 10, a lower end of the coupling portion 32 of the clamping screw 30 is likely to be contacted with an inner circumference surface of the through hole 11 of the insert 10. In the cutting tool of the embodiment of the present invention, the through hole 11 of the insert 10 includes a lower region 11-2 having a diameter which is gradually increased toward a lower end to prevent the coupling portion 32 of the clamping screw 30 from being interfered with an inner circumference surface of the through hole 11 of the insert 10.

[57]

[58] Below, a process for rotating the insert 10 on the holder 20 for changing the cutting portion which was worn away is described with reference to FIG. 2 and FIG. 3.

[59]

[60] FIG. 3 is a view illustrating a state where the insert is rotated with respect to the clamping screw and removed from the holder, once the user rotates reversely the clamping screw 30, the clamping screw 30 is moved inclinedly and upward. At this time, the head portion 31 of the clamping screw 30 is moved out of the through hole 11 of the insert 10, while a lower portion is screw-coupled with the a clamping hole 21 of the holder 20.

[61]

[62] In this state, the insert 10 can be rotated freely on the pocket portion 22 of the holder

20 about the coupling portion 32 of the clamping screw 30, and so new cutting portion of the insert 10 can correspond to the work-piece. Then, the clamping screw 30 is rotated to re-mount the insert 10 on the holder 20.

[63]

[64] On the other hand, in the state where a lower portion of the coupling portion 32 of the clamping screw 30 is screw-coupled with the coupling hole 21 of the holder 20, the head portion 31 ion 32 of the clamping screw 30 should be placed out of the through hole 11 of the insert 10, so the length of the coupling portion 32 on which the thread

portion 32- 1 formed should be larger than a height of the pocket portion 22 of the holder 20.

[65]

[66] A process for removing the insert older 20 from the holder 20 for replacing the insert

10 in which all the cutting portions were worn away is described below with reference to FIG. 2 and FIG. 4.

[67]

[68] FIG. 4 is a view illustrating a state where the insert is being removed from the holder.

[69]

[70] In a state shown in FIG. 3, the user move upward and then tilts the insert 10 to locate the through hole 11 of the insert 10 in parallel with the clamping screw 30. In this state (the state of FIG. 4), since the diameter (d) of the upper cylindrical portion 31-1 of the head portion 31 of the clamping screw 30 is smaller than a diameter (D) of the minimal diametral portion 11-3 of the through hole 11 of the insert 10, the head portion 31 of the clamping screw 30 can pass easily through the through hole 11 of the insert 10. Accordingly, the insert 10 can be removed from the holder 20 without detaching completely the clamping screw 30 from the holder 20.

[71]

[72] Although the preferred embodiment has been described with reference to the preferred embodiment thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

[73]

[74] For example, a shape of the clamping screw 30 constituting the cutting tool according to the present invention may be modified into a shape shown in FIG. 5

[75]

[76] FIG. 5 is a view corresponding to FIG. 2 and shows the cutting tool comprising the clamping screw having a modified shape. Therefore, the lower frustum portion 131-1 constituting a head portion 131 of a clamping screw 130 in the present invention is defined to include a variation having rounded convex surface as shown in FIG. 5.

[77]

Industrial Applicability

[78] The present invention is applicable to a cutting tool in which an insert can be rotated to change a cutting edge (or cutting corner) of an insert and an insert can be removed without detaching a clamping screw.