| 摘要 |
<p>A hand drill guide comprising an annular base (1) and a plurality of telescopic leg assemblies (5) distributed along the base. Each assembly has a hollow cylinder (7), fixed perpendicularly at one end to the base (1), and a rod (9) slidably mounted in the cylinder, the rod extending out of the cylinder through an opening. The drill guide also comprises an annular positioning head (17) to which the other ends of the rods (9) are fixed, and an annular drill holding assembly (21) mounted for selective location on the cylinders. The rod has a retaining ring (11) rigidly connected thereto at a given distance from its upper end to prevent the rod from escaping from the cylinder. A ring (41) is floatingly mounted on the upper portion of the rod inside the cylinder and two springs (43,45) act on the floating ring (41): one between it and the upper end of the cylinder and the other between it and the retaining ring, both springs being uncompressed when the retaining ring (11) is adjacent to the bottom end of the cylinder. A stiffening annular member (37) preferably interconnect the cylinders (7) at their open ends. In addition, the positioning head (17) is preferably provided with a manually operable finger (49) which can be moved to show where the center (47) of the drill guide is located, that is where the hole is to be drilled.</p> |
