| 摘要 |
PCT No. PCT/GB91/00399 Sec. 371 Date Sep. 11, 1992 Sec. 102(e) Date Sep. 11, 1992 PCT Filed Mar. 13, 1991 PCT Pub. No. WO91/13728 PCT Pub. Date Sep. 19, 1991.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 gear-box 11 attached below. An adjustable lever assembly 16, 18, 30 houses the lever 15 that can be removed via slot 17. The gear-box 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 gear-box 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.
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