| 摘要 |
<p>A spring balance comprises an object-receiving plate cooperating with a weighing spring and with a movable rack meshing with the pinion of a rotatable graduated disc cooperating with a fixed index. Zero-setting and calibration of the balance are provided independently. Firstly, the rack is set to a zero position, then the disc is independently set to indicate zero. A reference weight is placed on the plate, and the balance calibrated to indicate the exact weight by varying the transmission ratio of a transmission lever between the weighting spring and the rack. This transmission lever has an arm of adjustable length which, when the rack is in the zero position, is perpendicular to the direction of movement of the rack.</p> |
