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 ?

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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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