1. Nathaniel Watts, Justin Kibler, Angel Hambrecht, Maxine Laroche
All-Terrain Walker
Nathaniel Watts, Justin Kibler, Angel Hambrecht, Maxine Laroche

2. Agenda Project Overview Customer/Engineering Requirements
Selected Design
Project Status
Schedule
Budget
Major Issues and Findings
Objective Project Evaluation

3. Problem Overview Current State Desired State Project Goals
Existing posterior walkers cannot handle rough terrain
Desired State
Assist the user to navigate soft or changing ground conditions
Travel over obstacles that are found on a hiking trail
Project Goals
Maintain user independence
Identify Opportunities
easier to use
more durable
cost cheaper than current ruggedized walkers

4. Customer/Engineering Requirements

6. Selected Design Chose folding front to back due to stability concerns
Hinge the front wheels with push button hinges
Brake cables and caliper/rotor design for heavy duty brakes
Seat folds up using clamps and is supported by steel bar
Footrest is held on by steel bar and held in place by person/seat weight
Straps on the footrest help hold the user’s feet in place
Front wheels are 12” and swivel to get over <6” obstacles
Rear wheels are 20” to handle gravel and provide rear stability
Handles adjust using screw-type knobs
3D printed hand drive allows user to use upper body strength when tired

7. Project Status
Currently product is together with some issues that need to be addressed
The frame is completely coated and rust-proof
Seat folds correctly and can hold the footrest in place
Folding hinges work and allow for full foldability of frame
Handle adjustability is correct and functions
Casters swivel and move easily, but are not ideal
Brakes connect nicely with mounts to the frame
Handle grips and brake handles are a good ergonomic distance away
Seat back fabric is comfortable and sturdy

8. Schedule

9. Budget Overall we were given a $3000 budget
Between prototyping and our final proof-of-concept build, we spent $
Our proposal was for a product under $2000, but if you take out prototyping excess materials, our team was well under this limit

10. Major Issues and Findings
Weak Axle
Hubs can only accept an axle with a 0.21” diameter
Hubs need to be modified or replaced
Full weight testing is not possible without major damage to the walker
Seat and Footrest
For a 250lb person, a very thick and heavy piece of steel has to support the seat
Seat support design should be revisited
Footrest cannot fold far enough out of the way
A user cannot take a long stride without kicking the footrest
Brake System
Hydraulic brake calipers were ordered instead of cable calipers due to miscommunication.
Either new calipers, or new lines and handles need to be installed. Lines and handles would probably be easier and cheaper.
Due to the weak axles, the calipers rub on the rotors under heavy load.
Brake handles will need to be added to the hand drive handles.
Need to purchase hydraulic line splitters

11. Major Issues and Findings
Hand Drive
A part needs to be machined to attach the drive to the axle
Probably not worth the time since the axle needs to be replaced
Base needs to be machined to fit over the wheel spokes
Simply did not have time to do this
Better hardware should be installed
The nuts and bolts that we installed easily loosen. Nyloc nuts are preferable.
Ratchet spring needs adjustment
Handle hole needs to be bored bigger
It is currently 0.9” diameter and needs to be 1.1” diameter to fit powder coated handles.
Toggle switch needs to be added for reversing ratchet direction.
Hinges are “sloppy”
The two legs holding on the caster wheels have some unwanted movement
The bolt holes can be widened to allow for slightly bigger hardware
Should reduce the movement significantly but will be hard to accurately machine.
Casters are awkward
Due to the shape of the casters and the large wheel diameter, the casters are hard to get going in the right direction.
Caster design should be revisited

12. Objective Project Evaluation
This system meets some of the customer requirements, but needs more refinement until it can meet all of them
The walker is stable, but axles are unsafe for use at the current time
A redesign of the rear part of the walker might be needed
The walker weighs more than requested, but this was needed to meet the sturdiness requirement
The seat can support small users, but not the max weight
Folds nicely to fit into an SUV trunk, but not a small car