adjustable mechanical stilts 1 intro design problem testing design req budget conclusion
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ADJUSTABLE MECHANICAL
STILTS
INTRODUCTION
1
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
GROUP MEMBERSTrent HilliardIan JuurlinkBrad PoirierMitchell Weir
SUPERVISORDr. Marek Kujath
INTRODUCTION
2
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
CURRENT STILTS:
1. Used for tasks requiring small rises in elevation
2. Difficult to get stilts on
3. Difficult to adjust
4. Difficult to pick up objects
PROBLEM
3
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
LIFTING DEVICE: THE SCISSOR LIFT
DESIGN
6
• Fabrication• Snap rings• Bushings• Spacers
• Operations• Sliders• Pivots
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
LIFTING DEVICE: THE SCISSOR LIFT
DESIGN
7
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
• 4 lockable heights
• 15 inches of extension height available
• Height from ground to foot:• Min = 8”• Max = 23”
15”
LOCKING MECHANISM:
DESIGN
8
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
“LOCKED” “UNLOCKED”
0
1 2
3
CLOSED POSITION
INTERMEDIATE POSITIONS
EXTENDED POSITION
GAS SPRING DAMPER:
DESIGN
9
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
• Purpose: to overcome friction loss
• Damper applies continuous extending force
LATERAL LEG SUPPORT:
DESIGN
10
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
• Provides lateral stability• Ankle support• Extends with top foot plate
DIMENSION VERIFICATION:
TESTING
11
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
• Several design requirements based on physical dimensions and weight
Dimension Length Base Width Max Width Max Height
Average 12” 4.25” 6.8” 23.075”
Dimension Upper Step Lower Step Closed Height Weight
Average 19.825” 15.425” 7.875” 13.8 lb
STRAIN GAUGE TESTING:
TESTING
12
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
• Strain gauge installation• DAQ and VI system• Acquires voltage readings
STRAIN GAUGE TESTING:
TESTING
13
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
0.5 1 1.5 2 2.5 3 3.50.0
0.5
1.0
1.5
2.0
2.5
3.0
Stress at Various Heights (50 lbs)
Locker Side TopLocker Side BottomNon-Locker Side
LOCATION
STR
ES
S (
MP
a)
STRAIN GAUGE TESTING:
TESTING
14
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
40 50 60 70 80 90 100 1100.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
Stress At Lowest Height
Locker Top SideLocker Bottom SideNon-Locker Side
LOAD (lbs)
STR
ES
S (
MP
a)
DESIGN REQ.INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
1. Stilts can be attached in the ‘collapsed’ position.
2. Stilts must be able to extend 12” above the ‘collapsed’ position height.
3. Operator can walk on stilts while in the ‘extended’ position.
4. Operator must be able to extend and contract the stilts while stilts attached to operator’s feet. 9
CONCLUSION
DESIGN REQ.
17
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
5. The weight of each stilt will not exceed 25 lbs.
6. The stilts will fit foot sizes up to size 12.
7. The stilts will be operational for a total load of 220 pounds
8. Stilts will have non slip surface on the bottom to simulate normal footwear traction.
CONCLUSION
DESIGN REQ.
18
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
9. Base of stilt will fit in 6”x14” footprint.
10.Prototype stilts will have a maximum cost of $2500
CONCLUSION
BUDGET
19
Item Total CostStilts $412.50Hardware $192.40Aluminum Plating $265.55Aluminum Flat Bars $ 27.12Aluminum Round Bar $ 4.52Steel Round Bar $ 5.51Concept Prototype $ 50.00Actuator $ 22.40Locking Mechanism $ 8.25Damper $172.40Miscellaneous $ 24.56
TOTAL $1,185.21
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
DECEMBER BUDGET $1,274.16
CONCLUSION
20
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
POSITIVE FEATURES:
• Easy to obtain sitting and standing position while wearing stilts
• Quicker to adjust heights
• Safer to pick up objects
• No external energy input
FUTURE RECOMMENDATIONS:
• Reduce weight
• Install wire-less actuator
• Tuned Damper
• Redesign lateral leg support
CONCLUSION
21
INTRO
DESIGN
PROBLEM
TESTING
DESIGN REQ
BUDGET
CONCLUSION
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