Types of spring Used in Measuring Instrument

Types of spring Used in Measuring Instrument Points : Types of spring Used in Measuring Instrument, Mounting of spring There are two types of springs used:
(a) A hair-spring; usually of phosphor-bronze, which is attached to the moving system of the instrument.

(b) Flat spiral springs are used in almost all indicating instruments as the space required by these springs is less than for other types. Mounting of spring The inner end of the spring is attached to the spindle and the outer disc surrounding the jewel screw. This disc carries an arm which is slotted and splayed out at the end. The purpose of slotted extension are is to allow the spring to be coiled or uncoiled slightly, so that the pointer may be set at zero. The slotted arm is actuated by a set screw mounted at the front of instrument and, therefore, zero setting of the instrument can be done without removing the cover.