Page 25 - Personal Study Notes (Engineering Metrology - 22342)

Page 25 of 176

Q. Explain with neat sketches, construction and working of sigma comparator.

Components in Sigma comparator

1. The Plunger (The main part which will have the direct contact with the workpiece and
having a notch at its centre)

2. Knife Edge (Attached at the notch in the plunger to capture the movement of plunger)

3. Moving Block (Bears the Knife Edge. moving block is the part of the Cross Strip)

4. Cross strip hinge (Four flat steel springs arranged at right angles to each other and
having a pivot at its centre so-called cross strip)

5. Y-shaped arm (A metal forked arm, connects the cross strip to driving drum)

6. Driving Drum ( connects the pointer to the Y shaped arm)

7. Slit diaphragm ( Holds the plunger/Spindle in place)

8. a pointer

9. a Scale

Fig.

Construction and working of Sigma comparator

The Plunger will hold the contact with the workpiece, and it is positioned in place with
the help of slit diaphragms.

Engineering Metrology (Only For Personal Use) 17