List any eight component parts of prismatic compass with their function in brief.
Component parts of compass with their function.
Sr.No
|
Component
|
Function
|
1 |
Circular metal box
|
To protect needle and pivot.
|
2 |
Steel pivot
|
To carry magnetic needle and graduated ring.
|
3 |
Sighting vane
|
To sight the object.
|
4 |
Prism
|
To see graduation clearly.
|
5 |
Lifting pin
|
To lift the needle and hold against glass, thus prevent wear of pivot.
|
6 |
Glass lid
|
To protect the graduated ring from external effect.
|
7 |
Sun glasses/ ray shade
|
When sun or other luminous objects are to be sighted.
|
8 |
Metal cover
|
To protect glass lid.
|
9 |
Agate cap
|
To protect the prism from dust.
|
10 |
Ball and socket arrangement
|
For leveling the prism
|
11 |
Graduated ring
|
To take the bearing of line.
|
12 |
Break pin
|
To stop the movement of graduated ring on pivot.
|
13 |
Focusing stud
|
To adjust the prism to eye sight of observer
|
14 |
Magnetic needle
|
To obtain the north direction.
|