Engineeringdev

Comparator A comparator works on the relative measurement It gives only dimensional differences in relation to a basic dimension A comparator has to compare the unknown dimensions of a part with some standard (Basic Size) These are commonly used for linear measurement in mass production Classification Depending on the amplification system, Comparators are classified as Mechanical Comparators Electrical Comparators Optical Comparators Pneumatic Comparators

Mechanical Comparators : Mechanical comparator s are extremely convenient to use It does not require any external power for its operation The measuring head consists of the work contact plunger(Stylus) The movement due to size difference between standard and work piece operates a pointer The pointer moves over a dial This movement of the plunger is magnified by means of the gear train or levers The magnification of mechanical comparators is limited to 1000 These are cheap and intended to measure external surfaces However the mechanical devices are subjected to wear Types of Mechanical Comparators Dial indicator Reed type mechanical comparator The Sigma comparator

Comparator A comparator works on the relative measurement It gives only dimensional differences in relation to a basic dimension A comparator has to compare the unknown dimensions of a part with some standard (Basic Size) These are commonly used for linear measurement in mass production Classification Depending on the amplification system, Comparators are classified as Mechanical Comparators Electrical Comparators Optical Comparators Pneumatic Comparators

Reed type Mechanical Comparator The instrument used to measure linear displacement of spindle with the help of the reed mechanism is known as reed type Mechanical comparator. It is a device magnifying small motions of spindle. Constructional details : The reed mechanism is frictionless device for magnifying small motions of the spindle It consists of a fixed block `A` which is rigidly fastened to the gauge head case The floating block `B` carries the gauging spindle The floating block is also connected horizontally to the fixed block by reeds `C` A vertical reed is attached to each block with upper ends jointed together These vertical reeds are shown in fig by letter `D` A pointer is attached to this joint Working principle A linear motion of the spindle moves the floating block vertically upwards This vertical movement causing the vertical reed on the floating block to slide past the vertical reed on the fixed block The movement causes both reeds swing through an arc As the point is