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

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

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

Customer/Engineering Requirements

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

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

Schedule

Budget Overall we were given a $3000 budget Between prototyping and our final proof-of-concept build, we spent $2012.34 Our proposal was for a product under $2000, but if you take out prototyping excess materials, our team was well under this limit

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

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

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