Lecture 13 - Cadkey 1

Fundamentals of Engineering – Honors – ENGR H191

Question of the Day

What is the origin of the phrase“The Whole Nine Yards”?

ANSWER: Meaning to give absolute maximum

effort when trying to win or achieve something

From the 2nd World War; the American B-17 aircraft guns used ammunition belts that were nine yards long

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Fundamentals of Engineering – Honors – ENGR H191

Topics For Today

Sections Views Why section views are needed Types of section views References

BTG Chapter 6

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Fundamentals of Engineering – Honors – ENGR H191

Section Views

Goals Recognize various kinds of section

views, make full and half section views.

Improve visualization of interior features.

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Fundamentals of Engineering – Honors – ENGR H191

Section views are used when important hidden details are in the interior of an object. These details appear as hidden lines in one of the orthographic principal views; therefore, their shapes are not very well described by pure orthographic projection.

Section Views

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Fundamentals of Engineering – Honors – ENGR H191

Types Of Section Views

Full sectionsHalf sectionsOffset sectionsRevolved sectionsRemoved sectionsBroken-out sections

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Fundamentals of Engineering – Honors – ENGR H191

Cutting Plane

Section views show how an object would look if a cutting plane (or saw) cut through the object and the material in front of the cutting plane was discarded

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Fundamentals of Engineering – Honors – ENGR H191

Section LinesSection lines (crosshatching) are used to show where the cutting plane passed through solid material

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Fundamentals of Engineering – Honors – ENGR H191

Full Section View

In a full section view, the cutting plane cuts across the entire objectNote that hidden lines become visible in a section view

Hidden Lines are Visible

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Fundamentals of Engineering – Honors – ENGR H191

Full Section View

Shows cutting plane in the top viewMakes a full section on the front view

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Fundamentals of Engineering – Honors – ENGR H191

Full Section View

Note how the cutting plane is drawn and how the crosshatching lines mark the surfaces of material cut by the cutting plane.

No hidden lines on the section view, if possible.

Note: Interior lines behind cutting plane became visible.

Visible lines omitted

Incorrect

Correct

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Fundamentals of Engineering – Honors – ENGR H191

Multiple Sectioned Views

SECTION A-A

AA

SECTION B-B

B

B

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Fundamentals of Engineering – Honors – ENGR H191

Half Section View

The cutting planes do not cut all the way through to the object. They cut only half way. They intersect at the centerline.

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Fundamentals of Engineering – Honors – ENGR H191

Half Section View

Half Section used mainly for symmetric objects

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Fundamentals of Engineering – Honors – ENGR H191

Revolved Sections

Revolved sections examples show the shape of an object’s cross-section superimposed on a longitudinal view

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Fundamentals of Engineering – Honors – ENGR H191

Removed Sections Removed

sections are like revolved sections but moved aside. Note how they are named.

A

A

Section A-A

C CSection C-C

B

B

Section B-B

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Fundamentals of Engineering – Honors – ENGR H191

Broken Out Sections

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Fundamentals of Engineering – Honors – ENGR H191

Offset Sections

Offset sections are used to show interior features that do not lie along a straight line

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Fundamentals of Engineering – Honors – ENGR H191

Offset Sections

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Fundamentals of Engineering – Honors – ENGR H191

Conventional Revolutions

Used to make section views clear and avoid confusionAssociated with objects that have holes, ribs, spokes, or lugs in any combination equally spaced in a circular fashionNot projected orthographically to section viewExamples to follow

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Fundamentals of Engineering – Honors – ENGR H191Conventional Hole Revolutions

Note no hidden lines

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Fundamentals of Engineering – Honors – ENGR H191

Conventional Rib Revolutions

Note: Ribs not crosshatched

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Fundamentals of Engineering – Honors – ENGR H191Conventional Spoke Revolution

Note: Spokes not crosshatched

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Fundamentals of Engineering – Honors – ENGR H191Holes and Ribs in Combination

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Fundamentals of Engineering – Honors – ENGR H191

Assignment

Dwg 25 – F18-A Complete section views Due at end of today’s lecture

Dwg 26 – SECT 1-N Sketch Section Views Due at beginning of next lecture