Core drill
AssigneeKabushiki Kaisha Miyanaga
InventorMasaaki Miyanaga
Life of this patent
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Abstract
To provide a user-friendly core drill which, when forming a large-diameter cut hole by the core drill with respect to an object to be drilled, such as concrete, is able to easily form, for example, a chamfered portion or a countersunk portion with respect to an opening end portion of the cut hole. In a core drill comprising a base body including a shank and a drill core body including a drill cutting blade, a connection opening portion of the drill core body being attached to the base body, the connection opening portion of the drill core body is provided with a concave portion forming member including a large-diameter hole cutting blade, and the large-diameter hole cutting blade is provided outside the drill cutting blade in a radial direction of the connection opening portion.
Claims8
A core drill comprising:
- a base body including a shank;
- and a drill core body including a drill cutting blade, a connection opening portion of the drill core body being attached to the base body,
- wherein the connection opening portion of the drill core body is provided with a concave portion forming member including a large-diameter hole cutting blade, the large-diameter hole cutting blade is provided outside the drill cutting blade in a radial direction of the connection opening portion, and the base body, the drill core body and the concave portion forming member are connected to each other by causing an engagement projection formed so as to project in the connection opening portion of the drill core body to engage with an engagement concave portion provided on the base body, and
- wherein the concave portion forming member includes a concave portion core body which is radially larger than the drill core body, the large-diameter hole cutting blade is provided at a lower end opening edge portion of the concave portion core body, an upper end opening portion of the concave portion core body is reduced in diameter so as to form a connection opening portion, and the connection opening portion externally fits the connection opening portion of the drill core body so as to be connected thereto.
Dependencies are inferred from the claim text.