Patent ID: 6926476
Filing Date: 2005-08-09
Classification: B23B,Y10T

Abstract:
1. A core body locking device of a core drill wherein: a base body having a shank at an upper part thereof is formed with a fitting portion at a lower part thereof, the fitting portion being formed at an outer periphery thereof with a core body attaching portion having a shoulder portion comprising a step portion, the core body attaching portion being provided with an engagement concave portion; a cylindrical core body having a drilling blade at a lower end edge thereof is formed with an engagement projection protruding inwardly from an internal surface of the core body at an internal surface of an upper end portion of the core body; and the upper end portion of the core body is fitted to the core body attaching portion of the base body by engagement of the engagement projection of the core body with the engagement concave portion of the base body, characterized in that: the core body attaching portion of the base body is formed with a concave groove portion circumferentially adjacent to and continuous with the engagement concave portion and extending therefrom to a lower end of the base body; and a stopper member which has a lower end portion with an engagement pawl that is vertically movable within the concave groove portion and which is downwardly biased by a spring is disposed on the base body, wherein when the engagement pawl of the stopper moves to an unlocking position at an upper location, the concave groove portion of the core body attaching portion becomes continuous with the engagement concave portion, while when the engagement pawl moves to a locking position at a lower location, the engagement concave portion becomes separated from the concave groove portion by the engagement pawl.