INTRODUCTION
The Mountain Trike story began in October 2006 when I (Tim Morgan) commenced my final year project in Innovation and Engineering Design for my Masters degree at the University of Bath. I am an avid mountain biker, and wanted to design a product that would enable wheelchair users to experience the great outdoors in the same way I do on my bike. I was determined that through the project I would develop a completely new wheelchair design from scratch and create a true All Terrain Wheelchair (ATW).
USER CENTRED DESIGN
Extensive testing of standard wheelchairs revealed the following problems:
- The small wheels at the front of the wheelchair (castors) provided insufficient bump climbing ability.
- The castors also dug into soft ground.
- Poor articulation caused standard wheelchairs to lift off the ground on uneven obstacles.
- The brakes were inadequate to safely control downhill travel.
- Slope transitions, which were uncomfortable and potentially dangerous.
- Propulsion up slopes was very difficult as the wheelchair rolled backwards between pushes.
DESIGN
Supported by in depth research into papers written on many different aspects of wheelchair performance, user consultation, advice from medical experts, knowledge sharing with biomechanics professors, Triz techniques and assessment of current products, I developed initial design concepts.
BACKWARDS NOT FORWARDS
In order to quickly try out the fundamental principle of placing the large diameter wheels at the front, I modified my standard wheelchair so the seat pointed the other way and went out testing again. The difference in performance was profound.
STEERING THE COURSE
However, the chair was now dynamically unstable and would fishtail and spin out when cornering, making it very hard to control. I soon realised that this was caused by free-rotating castors and at this point created the initial design for Direct Steering. Cables would stop the rear castors spinning and enable the user to steer the wheelchair dynamically. This would completely revolutionise the way the device was directed as smooth turns could be steered, eliminating the awkward traditional ‘tank steer’ method.
SPRING IS IN THE AIR
Mountain bikes are able to travel over rough ground comfortably thanks to suspension. Problems with poor articulation of the standard four-wheeled wheelchair design could be overcome with a three wheeled setup, taking full advantage of the ‘tripod effect’ to ensure all wheels are in contact with the ground at all times. I added these factors together to create the design for the first prototype ATW. Months of hard graft in the workshop produced a fully functioning prototype.
TIME TO RIDE!
Eager to try out my design I took the Prototype for its first ride around my test route and was astounded by how well it worked. Ascent of steep slopes off road was possible, thanks to the propulsion system and braking between pushes to prevent rolling backwards. The suspension made the ride very comfortable and going up and down kerbs was no problem. The main success was the Steering which felt totally intuitive and made riding the ATW immense fun!
USER FEEDBACK
What really mattered though was what actual Wheelchair Users thought, so I set up a tests with various different Users.
PETER GRIFFITHS - AGE 62
“For a first prototype its 99% positive” (after whole afternoon testing on wide range of terrain)
“That’s brilliant! The brakes are fantastic” (comment relating to ability to apply brakes between pushes to prevent roll back between pushes)
“Initially the steering felt different, but now its second nature!” (after 10-15mins practise)
“I’m really enjoying this… highly entertaining” (whilst exploring the undulating grounds of Bath Uni)
“That was amazing! I did’nt feel a thing” (After successfully propelling across some deep, rutted JCB tracks left in the playing field)
RACHAEL GRAHAM - AGE 13
“Its amazing!” (after arranging a chance meeting in the park whilst Martin tested the ATW, Rachael and her Dad came over to us and Rachael was keen to give it a ride)
“Great fun” (making the ATW spin on the spot and weaving around the trees on and off the path, making full use of the Direct Steering)
“No dirty hands like I get with my chair” (whilst chatting about the problems found with her current Wheelchair)
TIM MARSHAL - AGE 60
"It is easier on the shoulders than any "direct drive - hands to the wheel - wheelchair, and has amazing manoeuvrability. Not being able to fall over backwards (the third, rear, wheel) makes it utterly safe, when the alternatives would be either a dodgy back wheel balance, or simply not attempting to cross that kind of ground."
MOVING ON UP
These tests provided excellent feedback and I reworked the prototype to include some of the changes suggested.
Experienced businessman David Rogers came in as chairman and together with fellow engineer John Wardle and IT expert Adam Alton we formed the Mountain Trike Company Ltd. The innovative features of the trike are now patent pending (patent number GB0710054.8) to protect the design from competitors.
The company is currently developing the design of a production model and seeking funding to enable us to take the product to market. Look out for the revolutionary Mountain Trike ATW at the International Rehacare show, Düsseldorf autumn 2010!