JPH0558221U - Core drill - Google Patents

Abstract

(57) [Summary] [Purpose] Without significantly reducing tool life,
The improvement of cutting speed is maintained for a long time. [Structure] A trapezoidal notch 4 is formed in the contact surface 3a of each chip 3 in the radial direction so that even if the chip is worn, the contact surface area of the chip 3 is almost constant and its change is reduced.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a core drill used for drilling reinforced concrete or the like.

[0002]

[Prior art]

 As shown in FIG. 1, a core drill generally comprises a bottomed cylindrical body 1 and a diamond tip 2 attached to the periphery of the open end thereof. It has a hole. It is known that such a core drill usually improves the cutting speed but significantly shortens the tool life when the diamond tip height is about half that of a new product. This is because the chip height is reduced and the chip width is narrowed. As a result, the area of the contact surface on the bottom of the chip is reduced, and the diamond abrasive grains on the chip surface are reduced, increasing the motor power per diamond abrasive grain. This is because

[0003]

[Problems to be solved by the device]

 The present invention provides a core drill capable of preventing a significant reduction in tool life when the diamond tip height is about half that of a new product and improving the cutting speed stably for a longer period than when it was new. With the goal.

[0004]

[Means for solving the problem]

 Therefore, the present invention provides notches such as a V-shaped groove and a trapezoidal groove on the bottom surface of each chip, or forms each chip in a trapezoidal shape. That is, the present invention provides a core drill in which diamond chips are provided at appropriate intervals on the periphery of an open end of a bottomed cylindrical body, or a notch such as a V groove or a trapezoidal groove is provided on the bottom surface of each chip, or Is formed in a trapezoidal shape.

When forming a notch in each chip, the notch may be formed on the circumference of each chip, but is preferably formed in the radial direction so as not to impair the strength of the chip.

[0006]

[Action]

 Even if the tip wears, the contact area of the bottom surface of the tip is almost constant, and the change is small.

[0007]

【Example】

 In the embodiment shown in FIG. 2, for each chip 3, a trapezoidal notch 4 is formed in the contact surface 3a on the bottom surface in the radial direction. As shown in FIG. 3, the notch may have an arc shape 5 or a V groove 6 instead of the trapezoid. In the figure, 7 indicates a body.

In the embodiment shown in FIG. 4, the chip 8 itself is formed in a trapezoidal shape.

[0009]

[Effect of the device]

 As described above, the core drill of the present invention has a substantially constant contact surface area on the bottom surface of the insert even when the insert is worn, and there is little change in the insert surface. It can be maintained for a longer period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a core drill.

FIG. 2 is a perspective view of a main part of a core drill according to the present invention.

FIG. 3 is a front view showing another aspect of the diamond tip.

FIG. 4 is a perspective view of a main part of another embodiment.

[Explanation of symbols]

3.8 ... Chip 4.5.6 ...
Notch 7 ... Body

Claims (2)

[Scope of utility model registration request] 1. A core drill in which diamond tips are provided at appropriate intervals on a peripheral edge of an open end of a bottomed cylindrical body,
Make a notch such as a V-groove or trapezoidal groove on the bottom of each chip,
Alternatively, a core drill in which each tip is formed in a trapezoidal shape 2. The core drill according to claim 1, wherein the notch is formed in the radial direction.