of the actuating rod, support bracket unit, pinion, and pointer shaft (fig. 4).
b. A blacklash spring provides for the elimination of backlash in the linkage, by keeping a constant tension for all
positions of the sector and pinion.
c. The amount of movement is proportional to the change in atmospheric pressure, the capsule expanding or
contracting until the forces acting upon it cancel each other. Since the pressure within the evacuated capsule is
insignificant, the pressure may be considered zero. Therefore. the only forces acting on the capsule are the atmospheric
pressure and the capsule resistance to distortion.