2. Comparator
Comparators are the instruments that are used to find out unknown size with known
reference Designed in a such a way that a small movement at measuring end is converted
into large movement in reading end Which means comparators are used to measure a
small difference in sizes by comparing them
4. High Magnification Gauge Comparator
There are two types of HMGC
Brook’s Level Comparator
Eden Rolt Comparator
5. Important note
It should be noted that all type of comparators are comparing instruments.
They are not Measuring Instruments it means there are only used for comprising of a
unknown size with the Known reference size
6. Our Topic
We are bound to discuss the Following comparator
Eden Rolt Comparator
7. Principle
It works on two main principle
Mechanical Magnification ( By lever Mechanism )
Optical Magnification ( Optical Shadow Mechanism)
8. Components of ER Comparator
Anvil ( Both Movable and Non-Movable)
Block ( Both Moving and Non-Moving )
Steel Strips
Pointer Strips
Pointer Arm
9.
10. Function of Component
Anvil
Purpose of Fixed Anvil is to provide the grip for our work-part
Movable anvil is used to play a part in providing Mechanical Magnification
Strips
The strips are used to provide displacement and cause of deflection of Pointer Arm.
Block
Causes twisting of a lever.
15. Specification
Each division of its scale represents 0.0002 mm so that by estimation it is possible to read
0.00002 mm.
This comparator is capable of calibrating gauges up to 25 mm.
Mechanical Magnification can be with in the range of 300-400x(with lever about 200mm)
Optical Magnification can be 60x
So the total Magnification can be obtained by this comparator is 20,000x
16. Manufacturing ease…………..
The space between strips and length of lever and rest of accuracy are not required to be
much Precise.
Because
That can be compensated by the facility of calibration.
Example
Gauge block (known size)..
17. Method of Calibration
Place Gauge of known size
Marks it reading as a reference( ‘0’ )
Remove Gauge
Place another unknown size gauge
Check out the reading
If the scale gives value beyond the ‘0’ then add value to reference
If a scale gives reading before ‘0’ then we subtract from reference.