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Design For Safety
By: Super Team 2Presented by: Tim Halsmer, Jamie Quinlan
Daniel Kascak, and Brandon Neale
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Overview• Five Steps for safety:
– Step 1: Split the Design into Systems– Step 2: Consider Redundancy– Step 3: List the Danger Features– Step 4: Look for Design Options
• Warnings• Protection• Avoidance
– Step 5: Deciding• Examples of Design for Safety• Discussion and Brainstorming
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Why Safety?
• People can get hurt– Lawsuits– Ethics– Sales
• Three of our design specifications deal with safety
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Step 1: Split the Design into Systems
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Cart
Drive train ControlsStructure
Motors
Gears BatteryUser Platform
Wheels
Seat
Basket
Chassis
Controller
Instrumentation
User interface
Wiring
Step 2: Consider Redundancy
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• Stuff breaks– A backup or auxiliary system will decrease the
probability of failure– Components are not
expected to fail at the same time
– Parallel and Series
Step 3: List the Danger Features• Every component must be evaluated
Individually• The components must be evaluated for
every stage in the use, recharging, and repair of the cart.
• Things to look for:– Stored Energy– Moving Machinery– Exposed Electronics– User Security– Hot, Parts or Corrosive / Toxic Chemicals 6
Step 4: Look for Design Options
• The three principles of design safety– Warnings– Protection– Avoidance
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Warnings
• Warnings are visual or auditory signals that alert people to the presence of danger.
• Warnings are generally the least effective of the principles
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Protection
• Control and regulation systems• Design diversity• Factors of safety• Protective devices• Protection is generally
more effective than warning but less effective than avoidance
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Avoidance
• Avoidance changes the design to eliminate the source of the danger.
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Types of Avoidance
• Fail-Safe: The component is designed so that if it fails it does so in a controlled, non-catastrophic manner.
• Safe-Life: The component is only designed to last a certain lifetime, and is replaced before that lifetime runs out.
• Redundancy: The component has a backup that can perform its function if it fails.
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Step 5: Deciding
• Finally safety features must be decided on and incorporated into the design.
• The decision must take into account more then just safety. The safety feature must all be evaluated in terms of:– Manufacturability/Assembly– Simplicity– Cost Effectiveness
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Structure Presented by: Jamie Quinlan
Structure
Basket User Platform Wheels
Seat Chassis
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Our Application
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ComponentsChassis Seat Wheels User
PlatformBasket
Stored EnergyMoving Machinery
X
Exposed ElectronicsUser Security
X X
Hot, Parts
Sudden Impacts
X X X X
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The three principles of design safetyComponent Warnings Protection Avoidance
Wheels(Moving Machinery)
Label Wheel Guard Using a wheel that does not have spokes
User Platform(User Security & Sudden Impact)
Label Use a non-slip adhesive and have handles.
Unavoidable
Basket(User Security & Sudden Impact)
Label Made from a suitable, see through material.
Unavoidable
Chassis(Sudden Impact)
N/A Front Bumpers Unavoidable
Wheel’s(Sudden Impact)
N/A Pneumatic Tires Unavoidable
Drive TrainPresented by: Dan Kascak
Gears Motors
Drive train
Battery
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Application to the Drive Train
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Components of Drive Train
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Motors Gears Battery
Stored Energy
X
Moving Machinery
X X
Exposed Electronics
X X
Hot Parts X XSudden Impacts
X X
The Three Principles of Design Safety
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Warnings Protection AvoidanceBattery Label Covers and
locationRemoving
hazardStored Energy
Keep safe in an electrically
insulated housing
Use low voltage
Exposed Electronics
Hide or route wires from user
Sufficiently ground
Use low voltage
Hot Parts Keep in a well insulated housing
Limit the current
Sudden Impacts
N/A Move from impact zones
Unavoidable
ControlsPresented by: Brandon Neale
Controls
Controller User interfaceInstrumentation Wiring
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Our Application
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Components
Hazard Controller Wires Instrumentation User interface
Stored Energy
X X
Moving Machinery
Magnetic Fields
X X X
High Temp X
Sudden Impacts
X X X
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The three principles of design safety
Warnings Protection AvoidanceController Label
http://pfl.labelserve.com/warning.htmlhttp://safetylabelsolutions.com
Covers and location
Removing hazard
Stored Energy Hide or route unit from userSufficiently ground
Essential component
Magnetic Fields Magnetic shielding Wire correctly to eliminate magnetic fields
High Temperature
Cover and add fans or heat pipe
Use components that do not generate large amounts of heat
Water damage N/A Keep safe from the elements
Nothing is water “proof”
Sudden Impacts N/A Move from impact zones
Human error is unavoidable
Questions ?
25
Discussion
• Finding dangers at all stages of cart use.
• Handout and Brainstorming
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Sources• https://mead.citl.ohiou.edu/courses/1/ME_470_A01_fall_2004-
05/db/_375859_1/design_safety_case_studies__textbook.doc
• http://www.nsc.org/istd/aboutus.htm
• Norton, Robert L. Machine Design: An Integrated Approach. Upper Saddle River, New Jersey: Prentice Hall, 2000
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