| 摘要 |
<p>This invention relates to a drill bit (1) for use in percussive drilling, the drill bit (1) comprising a body (2) having a front face (4), at least one button on the front face (hereinafter 'face button') (10), and a plurality of gauge buttons (20), each of the buttons (10 and 20) having a working face (10a and 20a). At least a portion of at least one gauge button (20) working face (20a) has a curvature which deviates further from being flat by comparison to a curvature of any curved portion of at least one face button (10) working face (10a), so that said portion of at least one gauge button (20) working face (20a) projects further than said portion of at least one face button (10) working face (10a).</p> |
