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Flashcards in Levelling A & B Deck (34)
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1
Q

Flat

A
  • to put on the same plane

- not always level

2
Q

Level

A

-to put on the same plane as the horizon

3
Q

Plumb

A
  • to align perpendicular to the horizon (vertical)

- think of a “plumb bob”

4
Q

Straight

A

-to be in direct line of (straightness)

5
Q

Square

A

-something aligned 90 degrees to a reference line

6
Q

Refraction

A

-light bends differently and travels at different speeds through different materials

7
Q

Diffraction

A

-shooting close to an edge can cause light to bend

8
Q

Vibration

A

-can travel through the stand and cause the target to appear blurred

9
Q

Pentaprisms

A
  • 5 sided prism
  • regardless of the angle at which the incident ray enters, the refracted Ray leaves at exactly 90 degrees
  • the image is not reversed
10
Q

Source of error

A

-rays can become distorted through a change in temperature, through glass (reflection and refraction)

11
Q

Optical micrometer

A
  • used for precision levelling to .001”
  • it’s parallel lens has the ability to bend the light rays and send them out again exactly parallel to the original line of sight.
12
Q

Coincidence level

A
  • used with tilting level for bucking in.

- bubbles fold onto itself

13
Q

Lenses & Prisms

A
  • light can be reflected on a polished surface with the angle of incidence being equal to the angle of reflection
  • in thinner material to thicker material the light always refracts towards normal
14
Q

Optical lines of sight

A
  • used instead of a tight wire or string line

- doesn’t sag, get kinked, vibrate

15
Q

Auto-reflection

A
  • auto means mirror (target)
  • uses a mirror to send a target image on the crosshairs back to the telescope (2 units working together)
  • when you see the reflected image you see the telescopes own crosshairs in the reflected image in the target.
  • problems with it are the possible incident rays and the mirror may be tilted.
16
Q

Auto-collimation

A
  • auto means mirror, Collimation means light
  • most accurate because it’s aimed at the reflected image of the crosshairs of the telescope itself.
  • sees one set of crosshairs when the object of 90 degrees
17
Q

Collimation

A
  • no mirror, two telescopes or one and a Collimator

- projects crosshairs of one telescope onto the crosshairs of the other telescope or Collimator both focused at infinity

18
Q

Collimator

A

-no eye piece, used for Collimation instead of a second telescope

19
Q

Optical Squares

A
  • mounted on a telescope and establishes a plane perpendicular to the reference line of sight
  • the pentaprism is the basis of this tool which allows the line of sight to change 90 degrees
20
Q

Rough alignment scales

A
  • used for levelling floors and setting the grade for drainage pipes.
  • accurately read to the closest 1/2 centimetre
21
Q

Obtaining an accurate reading?

A

-waving the rod and then take the shortest reading

22
Q

Precision scales

A

-accurate up to .001”

23
Q

Alignment bar

A
  • can measure over 100ft like rollers on a conveyor

- accurate up to .001”

24
Q

Alignment telescope

A
  • most accurate for establishing a straight lie of sight

- can do this by using an optical square, coincidence sliding level and a special plumb aligner bracket

25
Q

Tilting level

A
  • establishes a level plane and is strictly for levelling purposes
  • for comparing two or more heights at equal distances apart
  • readjust coincidence level before every move
  • eye to crosshairs, then the target to crosshairs
26
Q

Survey location ( benchmark)

A
  • to maintain accuracy or minimize inaccuracies the optical tool must be kept at equal distance from the back sight and the foresight
  • used as a reference point to set the final elevations of installed equipment
27
Q

How to get a straight reference line

A

-use an alignment telescope with an optical micrometer to level and crane rail

28
Q

Bucking in

A
  • aligning an optical tool onto two targets at the same time.
  • sight in far target, move laterally to near target or close to, rotate to sight in far target again and repeat.
  • must use a lateral adjuster with the jig transit
29
Q

Rough levelling

A
  • after setting up tripod tough level the tool by adjusting the fish eye bubble so you are within range of the coincidence level
  • bubble will move in the direction of your left thumb or towards any clock wise rotation
30
Q

Jig transit

A
  • to align and establish precise vertical planes and plumb lines
  • used to lay out a reference line at 90 degrees to each other (setting rollers 90 degrees to a reference line in a paper mill
31
Q

To focus

A
  • adjust crosshairs into focus

- then adjust object focus to get scale clearly on crosshairs

32
Q

Transit procedures

A

-first get your plane then move that line to another vertical plane

33
Q

Theodolites

A
  • can be used to measure angles in horizontal and vertical planes
  • used to set a conveyor incline
34
Q

Wire alignment

A
  • can get as close as .0001” with headphones and 6 volt battery
  • you would need a sag chart and the wire’s weight and size