BEAM ARREST (Patented)
The special construction of the beam arrest not only insures the positive alignment of the agate edges with their respective bearings, but is so designed that the center agate knife edge is directly over the center of the column. This is of great importance when the balance is loaded to full capacity and where the greatest precision is required. The beam arrest arms and the beam being pivoted about a common axis, the supporting points of the arrest arms move through the same arc as the supporting points of the beam, so that contact between edge and bearing always remains the same, thus the acme of balance construction is reached, the shifting of the beam with the consequent dulling of the agate edges rubbing over their respective bearings being entirely precluded.
MOVABLE INDEX OR ”AUTO-DEX” (Patented)
In adjusting the equilibrium of any balance it is customary to do so by means of the adjusting nut at the end of the beam: this necessitates the raising and lowering of the front sash several times and not infrequently introduces an error owing to the warmth of the hand when handling the beam. No. 9 Balance is equipped with a movable index (auto-dex) which is controlled by a thumb wheel situated at the front of the balance case (see illustration). A slight turn of the thumb wheel moves the index plate to the left or right as required until the indicator or pointer is coincident with zero of the index. It will be at one apparent that this method will prove a great time saver, obviating the necessary of touching the adjusting nut, or of recording the rest point, as the rest point and the zero point will always be coincident. With the movable index (auto-dex) the Agate Edges will last much longer, as it will be unnecessary to release the balance so many times. During one year this may amount to a thousand times or so.