Topic : COMPONENETS OF TRANSIT

THEODOLITE

GROUP OF STUDENT:

Name Enrollment Number

Prajapari Himanshu k. 140120106085

Patel Rahul 140120106088

Raithatha Nilesh 140120106089

INDEX

INTRODUCTION

Definition

MAIN COMPONENETS OF A TRANSIT THEODOLITE

INTRODUCTIONTheodolite is a basic surveying

instrument which is use for measuring vertical and horizontal angle.

Theodolite is more precise than magnetic compass.

Magnetic compass measures the angle up to as accuracy of 30’. However a vernier theodolite measures the angles up to and accuracy of 10’’, 20”

DefinitionA transit theodolite is one in which the

telescope can be revolved through a

complete revolution about its

horizontal axis in a vertical plane.

Main Components of Transit Theodolite

1. Trivet 2. Foot Screws3. Tri Branch4. Leveling Head5. Spindles6. Lower Plate7. Upper plate

8. A Frame9. T Frame10. Altitude Bubble11. Compass12. Tripod

1. TrivetIt is a circular plate having a

central, threaded hole for

fixing the theodolite on

tripod stand.

It is also called the base line.

2. Foot ScrewsLower part – The TrivetUpper Part – It is passes

through the threaded hole in the tribrach plate.

Foot screws is used for leveling the instrument.

3.Tri BranchThe upper parallel triangular plate carrying three foot

screws at its ends is called the Tri branch.

4.Levelling Head. It is consists of two parallel plates separated by the 3

leveling screws.

It gives support the upper

part of the instrumental and attaches it to the tripod

5. Spindles & Clamp1. Inner spindle2. Outer Spindles The inner axis is solid and conical and the outer spindle

is hollow.

6. Lower Platean annular horizontal plate with the graduations provided

all around, from 0 to 360°, in a clockwise direction. The graduations are in degree divided in to 3 parts so that each division equals to 20 min.

Horizontal angles are measured with this plate.

The size of the theodolite is defined by the diameter of horizontal circle.

7. Upper plate

Horizontal plate of smaller diameter provided with two

venires. on diametrically opposite parts of its

circumference.

They are used to read fractions of the horizontal circle

plate graduations.

The venires are graduated in 20 min and each minute is

divided in 3 to 5 parts making least count 20” or 10”.

8.‘A’ Frame or Standard

Two frames are provided on the upper plate to support the telescope, the vertical circle and vertical vernier scale.

These frame are known as standard or A-frame.

9. T Frame or Index barIt consists of a vertical leg known as clipping arm and a horizontal bar called the index arm engraved with venires C and D at its ends..

It is used as seat for altitude bubble and also provides vernier reading for vertical angle measurement

10. Altitude BubbleA sensitive level tube called altitude bubble, is attached to

the top of the T- frame.This bubble is brought to the center by the clip screw.A mirror is provided on the top of bubble.

11. CompassSometimes a circular box compass is mounted on the

vernier scale between the standards.

It is provided for taking the magnetic bearing(W.C.B) of line

12. TripodThe theodolite is mounted on a

strong tripod when being used in the field.

The legs of the tripod are solid or framed. At the lower ends of the legs, pointed steel shoes are provided to get them pushed into ground.

The tripod head has male screws on which the trivet of the leveling head is screwed.

Thank You….