| 摘要 |
<p>A drilling machine comprises a power motor unit (3) coupled with a spiral rod (2) and a drill bit shaft (1) and assembled in a mounting frame using a positioning disc. The arbor of power motor mounted on the mounting frame directly drives the drill bit shaft. The spiral rod is disposed at the periphery of the drill bit shaft. A plurality of cutters (12) are arranged between drill bit and spiral rod at the outer perimeter of the drill bit with a hollow guide notch above the cutters. The spiral rod (2) is mounted in the positioning disc (21) and engage a plurality of planet gears (23). When the arbor of power motor turns, it directly drives the drill bit shaft, drives the fast turning of the drive gear at the periphery of the drill bit shaft, resulting in different turning speeds with the drill bit shaft turning slowly and the spiral rod turning fast.</p> |
