Portable drill broach position control w.r.t. surface - using arm with flyweight and reference mark mounted on perpendicular axis, and transparent drum contg. further reference marks

摘要

The body of the drill (1) has an axis (2), perpendicular to the X-Y axis of the broach, on which is mounted a pendular arm having a flyweight (4) at its lower end. The arm extends above the axis (2) and has a reference mark (6) at its end which can coincide, when the axis of the drill broach is in the correct position, with a reference mark (7) on the periphery of a transparent drum (8) which surrounds the arm and forms an integral part of the drill. A second reference mark (10) is found on the drum periphery diametrically opposite the first so that the perpendicular position of the broach may be controlled whether the drill is above or below the surface. The drum is turned around the axis (2) to make the initial adjustment by means of a screw (14). The arm and its extension may consist of a roller (9) and the drum have a circumferential mark (12) which can coincide, when the axis of the drill is in the correct position, with a circumferential mark (11) on the roller.