Theodolite survey
The theodolite is the most
precise instrument used for measurement of horizontal and vertical angles. It
can also be used for various surveying operations such as establishing grades,
setting out curves, extending survey lines, determining differences in
elevation etc.
Two categories classified:
ü Transit
theodolite
ü Non-transit
thedolite Essential parts of a transit theodolite
Telescope:
A thedolite is provided with a
telescope to sight the distant objects clearly. It is mounted on a spindle
known as horizontal axis
Two spindles:
There are two spindles with axes
one inside the other. The outer axis is hallowed and its interior is ground
conical to fit the central vertical axis which is a solid and conical.
Lower plate:
The outer axis is attached to the
lower plate also called the scale plate, having its edge beveled. The edge is
silvered and graduated form Oo to 360o in the clockwise direction. The lower
plate is provided with a clamped tangent screw or the slow motion screw by
means of which it can be fixed at any desired position
Upper plate:
The upper plate also called the
vernier plate is attached to the inner axis. A clamp and a tangent or slow
motion screw are provided for the purpose of accurately fixing the vernier
plate to the scale plate. When both plates are clamped together and the lower
clamp or loosened, the instrument can be rotated about its outer axis; while if
lower plate be clamped and the vernier plate be loosened, the instrument can be
rotated about the inner axis. Before either of the tangent screw is turned, the
corresponding clamp must be tightened.
Level Tubes:
Two spirit levels called placed at right angles to
each other are fixed on the upper surface of the venires plate for leveling in
the instrument.
Vertical circle:
The vertical circle and graduated
and is attached to the horizontal axis of the telescope and thus it rotates
with the telescope. The circle is graduated either continuous from Oo to 90o.
By means of vertical clamp and tangential screw, the telescope can be set
accurately at any position in vertical plane.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.