| 摘要 |
<p>The invention relates to a continuously sharpening tap for big dimensions, used for threading sleaves needed for joining metallic pipes. According to the invention, the tap consists of a body (1) wherein there are removably mounted, some teeth (2) placed radially into a channel practiced inside the body (1), and axially, by means of some plugs (3) pressed therein, the clamping of the teeth (2) being carried out by means of some dull quills (4) and some differential screws (5) and, for the continuous sharpening, the teeth (2) are mounted inside the body (1), inclined by an angle (delta) in relation to a radial plane, and by reversing the same by 180 , in relation to the working position, there being done a continuous tap sharpening, by a cylidrical-helical grinding on the callibrating and leading portions on an normal lathe appropriately equipped, the tapering of the leading part being carried out by grinding with a semi-angle (beta), the value of an obtained relief angle (alpha) being equal with half of the radial angle (delta) for positionning the teeth (2).</p> |
