Presentation on theme: "SEED Down Hill Aerial Transportation Team Design Night Presentation May 4, 2011 Daniel Sturnick Chris Abbot-Koch Lance Nichols."— Presentation transcript:
SEED Down Hill Aerial Transportation Team Design Night Presentation May 4, 2011 Daniel Sturnick Chris Abbot-Koch Lance Nichols
Our client Mr. Milson needs a safe and reliable means of transportation from his house to his pond. He is no longer able to access his pond under his own power. The pond is located roughly 245 feet in the linear direction and has a 200 foot vertical drop in elevation. There are obstacles such as wetland and rough terrain standing in the way as well. 245 ft
Solution Cable Cart System Let’s take a minute to explore the design
Design Process Early Leading Design: Tracked Tramway ▫Pros: Safety – one the ground Reliability Affordable ▫Cons: Doesn’t account for change in elevation, can’t get all the way High Maintenance ▫Design Change => Go over the change in elevation, get up in the air
Design Process Final Concept: Cable Cart Lift ▫Customizable Direct Porch and Pond Landings Through Cart Fit to Scooter ▫Engineerability Design flexibility ▫Minimize Material Use ▫Maximize client unique experience while riding and aesthetic appeal
Constructability 1.Lay out design over field: final measurements 2.Excavate for concrete: Locations for top/bottom/intermediate footers. 3.Form concrete how to get concrete poured (portable mixer vs. chute) 4.Intermediate pole installation 5.Install/fix cables 6.Install drive/control system 7.Install cart on cables
Cart Designs Design 1 Length: 5’ Width: 4’ Height: 3’ Door opens to be 29” wide Metal frame: 2” thick Aluminum Square Stock
Cart Designs Design 2 Length: 4’ Width: 3’(Handicap accessible standard) Height: 3’ Collapsible front and rear door that turns into on/off ramp Transparent sides and bottom
Cart Designs 3’ x 4’ x 3’ design Rollers set at pitch angle of 14 o Stabilizing Cable Rollers set 2’below cart Transparent Walls and Floor. Gate deploys into a loading/unloading ramp. Design 3
ASME A17.1 Safety Code for Elevators and Escalators
Key Requirements for Private Residence Inclined Elevators : Car must be enclosed on all sides to a height of 42 inches. The inside net platform area may not exceed 15ft^2 The fixed cables may not be less then 0.25 inches in diameter, while the hoist cables may not be less then 0.1875 inches in diameter with both having a factor of safety of 8. The driving motor may not be mounted to the same structure as the fixed cable. An emergency switch must be located on the car operating panel. Hand rope operation shall not be used…
Electric Motor With Worm-Gear Drive Mechanism Large speed reduction ratio Self-locking, the gear cannot reverse drive the worm Good for low horsepower applications Low cost High output torque in a small package
Electrical Systems ACH550 Practically Solves all of our electrical needs: - Ramp Up/Ramp Down - Speed Governor - Forward/Stop/Reverse Can be connected right to a household circuit breaker.
Electrical Systems -As the cart approaches the upper and lower landing docks, there will be a pair of limit or rocker switches. -As the cart rolls over the first switch, it will send a signal to the variable frequency drive (ACH550) to ramp down the motor. -As the cart rolls over the second switch, it will send a signal to the VFD to stop the motor.
Human Perception of Vibrations There is a range of frequencies that are physically disturbing to the human body. 2.5-10 Hz Outside of these bounds, there is no disturbance to the human body.
Tension Calculations The largest deflection will be when the dead and live load are in the middle of the track. Tension calculations had to be conducted at this point.
Tension Calculations Frequency – F= (2∏ F) 2 m Stiffness – k = δ =m/k Where: = Live load + Dead load = Deflection of cable at midpoint
Tension Calculation By making a right triangle, we can solve for β 2, since we know the angle the tension cable makes with a horizontal ( 14.47 o ) β 2 = 180 – 90 – 14.47 = 75.53 o Knowing β 2, we also know µ 1. µ 1 = 180 – 75.53 = 104.47 o β 2 µ 1
Tension Calculations Now knowing C 1, B 2, δ, µ 1, β 2, we can apply the Law of Sines and Cosines to solve all remaining unknowns. C 2 = A 2 + B 2 – 2ABCos(c) Once the tension angles, α 1, α 2, the tension can be found by the equation T =
Footer Calculation Sum of the Forces in the X and Y direction and a sum of the moments about point O. H3H3 H1H1 LL/ 2 mg S f2 T Point OH2H2 S f1
Footer Calculation Sum of the Forces in the X direction yields Tcos(14.47) – S f1 – 2S f2 = 0 Sum of the Forces in the Y direction yields Tsin(14.47) – mg = 0 Sum of the moments about point O yields Tsin(µ)*(3L/8) – Tcos(µ)*(h 1 + h 3 /2) - S f1 *(h 1 / 2) -2S f2 *(H 2 / 2) - W ((2h 2 mgL + 6h 2 mgL + L 2 h 3 + 4hL 2 ) / (8h 1 L + 8h 2 mg +4Lh 3 ))
Support Column Footer Calculations Sum of the Forces in X and Y will give sufficient information to solve for footers. SfSf mg T T
Safety Features Emergency Break on Cart Speed Governor Acts as an Additional Safety Break at motor Safety Switch at Landings so motor can’t engage with gates open. Back-up battery for power failure
Future Steps Get design out there is search of outside funding Transfer design to Professional Engineer Sign contractor to project Install lift for David Millson to get back down to his pond
A special thanks to Professor Eric Hernandez, our mentor on short notice, to David Boehm, with help from Engineering Ventures, and to the excellent clients, the Millson’s for their hospitality and the great design opportunity.