Senior Design Ideas Team INASAD Members: Jose Medina Joseph Leone Andrew Merk Alex Sanders Michael Fox

Agenda: Midterm recap Final design modifications Final design Subsystem overview Engineering analysis Prototyping modifications 2

Project Topic Fluorescent Light Changing System 3

Problem Statement Hundreds to thousands of fluorescent light bulbs in an average building. Changing bulbs is dangerous and time consuming To improve this process, an instrument which from the ground could: grasp the light twist the bulb to unhook it remove it install a new light 4 4

Goal The overall goal of this project is to create a tool that: Simplifies the removing and installation of fluorescent light bulbs Makes the overall task safer 5 5

Customer Needs Operators Needs: Manager or Owners’ Needs Minimize the use of a ladder Operable by one person minimal physical and mental effort Decrease the time to change a bulb by hand Reliable and easily maintained Manager or Owners’ Needs Limits number of employees and time needed to perform the task Decrease injuries Cost offset by decreased number of people and hours 6 6

Midterm Concept 7

Final Design 8

Post Midterm Modifications Tilting mechanism Safety Shield 9

Bulb Collecting Subsystem Installation/Removal System Consists of: 2 U-shaped areas for bulb to fit 1 for bulb removal 1 for bulb installation Using a cam, spring and pull cable the system will rotate 90 degrees Simplifies removal and installation process Improves alignment

Bulb Rotating Subsystem Rotation System Consists of: Crescent shaped base Spring Pull cables Activation gripping handle

Bulb Gripping Subsystem Suction Cup Gripping System Consists of: 3 suction cups for each sled Suction cups attached to a crescent shaped base Force needed to rotate a light bulb into removal position is 2.8 lbs. Each suction cup can with stand an average force for 1.7 lbs 3 suction cups = 5.1 lbs of force

Safety Subsystem Material Thin Polycarbonate Flexible See through Polycarbonate helps balance the tool during operations 13

Bowing Subsystem Trapezoidal Bowing System 4 adjustable bars for stability 2, ¼ circle adjustable disks 15°-90° adjustment 1 Lever adjustment bar

Base/Raising and Lowering Subsystem Tripod base Rack and Pinion height adjustment Allows for large and precise maneuvering Hand crank or power drill adjustable 15

Normalizing Subsystem Leveling mounts normalize tool on uneven surfaces 16

Types of Engineering Analysis Implemented Material Selection Strength of Materials Stability During Operation Kinematic Analysis Spring Selection Analysis Fatigue Analysis Human Interface Tolerances Performance Analysis 17

Engineering Analysis to be Discussed Material Selection Strength of Materials Stability During Operation Kinematic Analysis 18

Material Selection Baseline weight found using Aluminum Baseline load calculations preformed (using Al as material) Part most likely to fail was Bowing Mechanism Locking Pin Stress = 441.3 psi x safety factor 0f 3 = 1323.8 psi Used CES EduPack 2008 Parameters Yield Stress > 1323.8 psi Low Ductility Elongation of 1020 HR steel = 36% High Hardness Material Chosen Polystyrene (20% Glass Fiber) Mention that the calculations were redone using the chosen material and will be shown later. 19

Material Selection Polystyrene (20% Glass Fiber) Yield strength (elastic limit) 8 kpsi (55.2 MPa) Tensile strength 10 kpsi (69 MPa) Elongation 1 - 1.3 % Hardness - Rockwell R 113 – 125 Fatigue strength at 107 cycles 3.9 kpsi (26.6 MPa) Overall cost of Polystyrene material for tool body $58 20

Material Selection Polystyrene (20% Glass Fiber) vs. Polystyrene Elongation = 10-20% Rockwell Hardness R = 75-95 Polystyrene (20% Glass Fiber) Elongation = 1-1.3% Rockwell Hardness R = 113-125 93.5 % decrease in elongation (lower ductility) 33.6% increase in hardness Don’t forget to mention that the Polystyrene (20% glass fibers) was chosen over basic polystyrene even though the strength is way to high. 21

Strength of Materials Parts more prone to Failure Rotation shaft Bowing mechanism lock pin Bowing mechanism top tilt pin Bowing mechanism bottom tilt pin Tilt plate teeth Adjustable tilting bar 22

Strength of Materials Overall results Bowing mechanism lock pin Shear Stress experienced by part =191.8 psi Safety Factor = 41.8 23

Stability During Operation Wbase = 54.6 lbs (needed not to tip) Wactual, base = 8.7 lbs. Wadded to base = Wbase - Wactual, base = 45.9 lbs 24

Kinematic Analysis Distance the sled needs to travel to rotate the bulb 90 ° S=Rθ S=arc length R=radius of race θ=90° S=2.3 in. 25

Financial Analysis Material Cost Labor/Production/Shipping Costs $256 (based on store prices) 15-20% reduction in cost from mass production would be assumed Labor/Production/Shipping Costs $ 60(approximate) Total Cost $316 (based on store prices) Sales Price $998

Financial Analysis Georgia Institute Of Technology Labor Cost $35/hour Product Time Savings 30% Company Savings $11.67/hr $0.391/light bulb ≈ 2 minutes to change a light bulb

Financial Analysis Company savings Product Payoff Rate (PPR) $11.67/hr. $0.391/light bulb ≈ 2 minutes to change a light bulb Product Payoff Rate (PPR) *PPR = 85.5 hrs. (about 2 work weeks) *PPR = 2,553 Light bulbs *( Estimates do not include savings from possible reductions in insurance cost as well as worker compensation claims.)

Prototype Modification Tilt Plates Housing Spring Material Selection Added Weight to Base Pull cables replaced with fishing line hand pulled 29

Prototype Modification Tilt plate side panels 30

Prototype Modification Housing Springs Due to size and strength requirements the spring need to be fabricated Replaced with badge retracting clips 31

Prototype Modification Materials Housings and rotation sleds High density Polyethylene Rotation bar and Tilt adjusting bar HR Steel Tilt Plates Aluminum Tilting legs, and Rotation support Structure PVC pipe 32

Prototype Modification Replace pull cables with fishing line Due to cost of cables ($42/cable) fishing line was substituted and will be hand pulled to create the needed motion. 33

Video http://helix.gatech.edu/Classes/ME4182/2009S1/projects/Team_INASAD/gallery.html 34

Future Improvements Storage Base Attachable Light Provide base weight for stability Would hold replacement and old bulbs Attachable Light Would illuminate areas of low lights as well as areas with high ceilings 35

Future Improvements Alignment Camera Height increase Would provide images of the working area on a screen which would be at eye level. Height increase Increasing the reachable height would make the product more usable at all ceiling heights. 36

Fluorescent Light Changing System INASAD Fluorescent Light Changing System 37