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Lesson
14: Drawing the Trunion Block in Ortho, Iso and 3d |
FIG. 14a (the Trunion Block)
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The word Trunion means a pin or pivot on which something
can be rotated or tilted; especially : either of two
opposite gudgeons on which a cannon is swiveled.
The discovery of the trunion followed the wheel.This
part has an incredible history of use and design,
depending on what was needed to pivot.
Trunions are used in artillery weapons ancient and
contemporary. Trunions are used in automobile engines
to mount bearings for the crankshaft. There application
and use represent a wide span of engineering that
continues on today.
In lesson 14 you will be drawing a Trunion Block
as an example of the meaning of trunion which is to
pivot or rotate another part whether a shaft or a
cannon.
Connecting Your Learning
As you work your way through this lesson, you should
reflect on the following questions:
How did the trunion get its name?
How is the ellipse used to obtain the shape of this
model?
How can the Isometric view be created with the trunion?
Which view will I use to extrude this model for a
3d illustration?
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The State of Arizona has assembled Drafting
standards to make sure that Instruction is thorough
and well thought out by the instructor. By clicking
on the hyperlink below will upload to your browser window
the entirety of these standards. The standards that
are addressed in this lesson are below the hyperlink.
1.0 USE BOARD DRAFTING EQUIPMENT,
INSTRUMENTS AND MEDIA.
2.0 DEMONSTRATE SKETCHING, LETTERING,
AND LINE SKILLS.
- 2.1 Demonstrate freehand sketching skills for drafting
applications.
- 2.2 Demonstrate lettering skills.
- 2.3 Demonstrate line work.
6.0 DEMONSTRATE GEOMETRIC CONSTRUCTIONS
- 6.1 Measure Geometric Constructions.
- 6.2 Develop Geometric Constructions.
8.0 APPLY BOARD DRAFTING SKILLS TO COMPUTER-AIDED
DESIGN/DRAFTING (CADD)
- 8.1 Demonstrate computer skills for a CADD system.
- 8.2 Create dimensional CADD entities.
- 8.3 Create 3 dimensional CADD drawings.
The State of Arizona has also assembled Math
standards and many of these apply directly to
the vocational subject area of Drafting. Drafting
is a very precise discipline and the use of mathematics
is integral to design and manufacturing. Below are
the math standards that are involved in this lesson
1M-P1. Compare and contrast
the real number system and its various subsystems
with
regard to their structural characteristics
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PO 2. Compare subsets of the
real number system with regard to their properties
(commutative, associative, distributive, identity,
inverse and closure properties)
1M-P2. Construct, interpret and
demonstrate meaning for real numbers and absolute
- PO 3. Solve real-world distance problems using
absolute value
- PO 4. Determine, among the solutions to a real-world
problem, which, if any, is reasonable
- PO 2. Define absolute value as the distance from
the origin
4M-P1. Interpret and draw three-dimensional
objects
- PO 1. Sketch prisms, pyramids, cones, cylinders
and spheres
- PO 2. Classify prisms, pyramids, cones, cylinders
and spheres by base shape and lateral surface shape.
- PO 3. Recognize the three-dimensional figure represented
by a two-dimensional drawing.
- PO 5. Make a model of a three-dimensional figure
from a two-dimensional drawing and make a two-dimensional
representation of a three-dimensional object (models
and representations include scale drawings, perspective
drawings, blueprints or computer simulations)
4M-P4. Deduce properties of,
and relationships between, figures from given
assumptions
- PO 1. Find similarities and differences among
geometric shapes and designs using a given attribute
(e.g., height, area, perimeter, diagonals and angle
measurements)
- PO 2. Identify arcs, chords, tangents and secants
of a circle
- PO 3. State valid conclusions using given geometric
definitions, postulates and theorems
- PO 4. Represent pi as the ratio of circumference
to diameter
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Lesson
Objectives
By the end of this lesson you should be
able to:
1. Draw the orthographic views of the
trunion and dimension the model.
2. Identify the isometric angles used to create isometric
views (30, 90 and 150 degrees)
3. Create an isometric view using the two orthographic
views of the Trunion Block.
4. Adjust the dimscale overall and linear to reflect
full scale dimensions in the ortho/iso drawing.
5. Create the 3d model of the Trunion Block from the
front orthographic view.
6. Working with colors for visualization enhancement.
7. Using 2 views to illustrate a model.
8. Be able to use draw the ellipse to illustrate circles
and in this case a hemisphere in model.
9. Be able to illustrate a hole with a hidden line property.
Key
Terms
"click
on the key on any of these terms and it will hyperlink
to the course glossary" |
The 14th
model you will be drawing is called the trunion block
and only 2 views are necessary to describe this object
in blue print: top and front views.
Insert your
Lesson 14 media disk into your CD drive and begin listening
to the avi file: lesson 14a. You can open up both software
programs: ACAD and your media player at the same time
and toggle back and forth between screens, and be able
to draw and listen simultaneously.
Below is
an example of what your completed drawing should look
like. Pay attention to details so you can obtain all your
points for this assignment. It is always better to get
it right the first time, especially when you have what
the finished product should look like. I will mention
in the media files about the Dim-scale of the dimension
text.
The next part of Lesson 14b you will be creating the
Isometric view of the Trunion block. This particular drawing
can be easily drawn with the benefit of using "boxing
in", also called "the Glass Box" . The
ellipse command is used to create the pivotal aspect of
this part.
Please Insert the Media Disk and listen to lesson 14b.
Below is what your completed assignment should look like
when finished.
Please Insert the Media Disk labeled Lesson
14 into your CD drive of your computer and begin listening
how to draw the 3d model of the trunion block. The lesson
avi is titled Lesson 14c and below is an example of a completed
accurate model of the trunion block. You will submit your
drawing using the orbit command to orient the model to its
true isometric "working view".This is what your
completed 3d assignment should look like.
*Note:
The Lessons are best viewed with real player, or Windows
Media Player 9 for 2000 Professional and Version 10 for
XP.
After
completing each lesson attach your drawing to an email and
send to your Instructor's email.
email:
losimilar@yahoo.com
Your
Text Book and Reading Assignments
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Text:
Autocad Drafting by
Grout, Resetarits and James
Use
this text as a reference to the media disks that you
are using for the Semester.
Lesson 14 assessment comprises:
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Lesson 14a submitted as a dwg. file
(10 pts.)
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Lesson 14b submitted as a dwg. file.(10
pts.)
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Lesson 14c submitted as a dwg. file.(10
Pts.)
Rubrics for Grading: The drafting
standards for assessing the quality and accuracy of your
drawings are as follows: Neatness, Accuracy and Lines and
Lettering. One half of one point (.5) will be taking off
your score in relation to NALL.
Submit by email attachment all of
the above lessons as dwg. files and send to your Instructor
whose mail address is. losimilar@yahoo.com
Your Instructor will grade your drawings
within 24 hours and email you back the grade/assessment
of your work. You should take allot of pride in your work.
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