Engineering
Creating objects that use verified technological
principles to help humans meet their needs.
Kinds?
Mechanical, Chemical, Biomedical, Electrical,
Computer, and Civil Engineering.
What is Mechanical Engineering?
It is a branch of engineering that deals
with the design, construction, operation
and improvement of systems or technical
objects.
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What is a mechanical function?
It is defined as the role played by a
mechanism* inside a more or less
complex object.
* A mechanism is a part of substance
having a specific function.
YouTube - mechanical engineering
The Five basic Mechanical
Functions?
Typical Function
Description
Link
2 or more parts are connected
together.
Guiding Control
One or more parts allows a
part to rotate, translate or
both together.
Lubrication
A substance that reduces
friction between two or more
parts.
Seal
A mechanism that prevents
leaks of gases, liquids, or
solids from an object
Support
Part that is used to hold up
another corresponding part.
LINKS
How objects are “connected together”.
Guiding Control
“allows a part to rotate, translate or both”
Lubrication
“reduces friction”
Seal
“prevents leaks”
Support
“hold up other corresponding parts”
A Mechanical Object
Link
Support
Guide
Control
Seal
Lubrication
How to Describe Links
The link function is the connections
between two parts or more.
They exist when an object is composed of
more than a single part.
Kinds of Links
Direct Link
Connects parts with no other
device being used.
Lego
Indirect Link
Connects parts by using another
device to hold them together.
Nail
Bolt
Screw
Removable Link
Non-removable Link
Link can be removed without
damaging anything on the object.
Connected parts can not be
removed without damaging the
object.
Nut and Bolt
separates the
seat from the post.
Welded frame
can’t be
separated.
Rigid Link
Elastic Link
Pieces of the object can not be
interchanged when assembled.
Allows for parts to change
position.
Table pieces.
Shocks or Springs.
Complete Link
Partial Link
No parts move independently of
each other. All move together.
Parts can move independently to
each other.
Hammer
C-Clamp
A link always has 4 of the 8 properties; they have one from each
pair of properties: Direct or Indirect;
Removable or Non-Removable
Rigid or Elastic
Complete or Partial
Example: A Door, its Hinge, and the Door Frame.
Link
Property
Direct or Indirect?
The door & its frame are
held by hinges which need
screws.
INDIRECT LINK
Removable or
Non-removable?
The door and hinges can be
removed by unscrewing
them.
REMOVABLE LINK
Rigid or Elastic?
Neither the door’s wood or
hinges metal can be
stretched.
RIGID LINK
Complete or Partial
The door can move freely
without causing the door
frame to move. PARTIAL
LINK
Your Turn
Describe the four characteristics of the links in each of
the following examples:
Create a basic design plan using a ruler, BUT ONLY
SYMBOL THE LINKS AND WHAT 4 PROPERTIES
THEY HAVE.
a) A table and its four legs connected with screws.
b) A pair of scissors.
c) A pen and its cap.
Motion Transmission Systems
Is defined as a system’s ability to transmit the
same motion from one part of an object to another.
When we pedal a
bicycle, we
transmit a force
into the peddles,
which then
transmits the
motion into the
bike’s wheels via
the chain and
gears.
Question?
Does it always
have to move in
the same way?
Bidirectional Spiral Motion transmits into
Bidirectional Rectilinear Translation.
Egg Beater Hand Out
Antique Egg Beater Motion Transmission System
___________________________________________________
___________________________________________________
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Link
Indirect
Non-removable
Rigid
Complete
Support
Guide
Control
Seals?
Lubrication?
Keep this sheet handy, you will need it later.
Do Motion Systems need…
Lubrication*?
Guiding Control*?
Seals*?
Support*?
Not all of them, but where there is motion, usually
lubrication* is needed for limiting friction….which
means there should be seals* keeping the lubricant
stored or inside the mechanism. Most movements
require a guide control* so the “pieces don’t fly” as well
as giving support* frames where the mechanisms won’t
interfere with each other. Plus it depends on what the
object is used for.
YouTube - ENGINE ANIMATION....
From the Video, did you see evidence of each
of the following Mechanical Functions?
Lubrication.
Oil for the pistons, and gears.
Guiding Control:
The Cylinders the pistons move through.
The Gears proper rotation.
Seals:
Keep the lubricants and gas from leaving the engine.
Support:
All the nuts and bolts, molded frame.
Types of Transmission Systems:
Mechanisms
Motor Mechanism
Definition
Mechanism of a system on which
force is applied.
Bike: Pedals transmit leg energy.
Intermediate Mechanism
Mechanism of a system that
transfers the action of a motor
mechanism (driving force) to a
receiving mechanism
Chain on a Bike
Receiving Mechanism
Mechanism of a system that
receives the motion through an
intermediate mechanism.
Rear Wheel in a bike.
Chain and Sprocket System
Back Wheel
Chain
Pedal
(Receiving Mechanism)
(Intermediate Mechanism)
(Motor Mechanism)
If any of the pieces of the mechanism fail, what would the possible result be?
Antique Egg Beater Motion Transmission System
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___________________________________________________
_________________________________
Link
Indirect
Non-removable
Rigid
Complete
Motor Mechanism
Intermediate
Mechanism
Support
Guide
Control
Receiving Mechanism
Different Types of Motion
Transmission Systems
Chain and Sprockets
Belt and Pulley
Gears
Friction Gears
Wheel and Worm Gear
Simple Machines
Antique Egg Beater Motion Transmission System
Changed rotation direction 90o.
Twice the energy, with the same energy output.
Transformation Systems
The ability of one mechanism to CHANGE the
nature of motion in another mechanism.
Options: 1. Rotation into Translation;
2. Rotation into Rotation;
3. Translation into Rotation;
4. Translation into Translation.
Rotation:
Translation: A
B
B
Examples Extraordinaire!
B
Motion Transformation of a Bicycle
Rotation
Motion
Translation Motion
Therefore, a bicycle transforms its motion from:
Rotation Motion into Translation Motion.
Different Types of Motion
Transmission Systems
Name of System
Screw and Gear System
Ex: ________________
Wheel and Worm Gear
Ex: ________________
Cam and Follower
Ex: ________________
Diagram of System
Motion Transformation Systems
Is the The ability of one mechanism to
CHANGE the nature of motion in another
mechanism.
Example: C-Clamp
Rotation Motion
Translation Motion
Rack and Pinion Steering
Rack and Pinion: Rotation Motion
Translation Motion
Cam and Follower
Rotational Motion
Alternating Translation Motion
Major Examples of Motion Transmission Systems
Clock Towers have 4 types of motion transmission systems in use.
Belt and Pulley
Gears
Friction Gears
Wheel and Worm Gear
Any Mechanical Functions?
Links?
Guiding Controls?
Lubrication?
Seals?
Supports?
Type of Motion Transformation?
Translation Motion
Rotational Motion
Personal Questions
Pg. 371 Synergy;
Questions: 1-7, 10-12.