| 摘要 |
<p>An underfloor drilling jig comprises a fixed outer frame (28) and an inner frame which slides within. A standard electric drill (10) is clamped to this inner frame in a vertical position with an angled gearbox (11) attached below. An adjustable lever assembly (16, 18, 30) houses the lever (15) that can be removed via slot (17). The gearbox (11) is modified by a 'blister' (12), which houses the pressure screw and housing (14). The lever (15) applies pressure to the drill bit (38) via gearbox (11). Steady-plate (36) holds the chuck (37) steady when drilling. Jaws (25) of clamp-plate (24) grip the flange of the rolled steel joist (26) when pressure is applied to the lever (15). Height adjusting screws (22) adjust the height to a horizontal position, but the front one is only necessary when drilling wooden joists.</p> |
