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Mountain trike: all-terrain wheelchair.

In their standard design format, wheelchairs are almost impossible to use on most woodland and country paths. A new design has arrived that promises to make this all a thing of the past

Many wheelchair users find themselves extremely frustrated by the limitations imposed on them by the mobility of their chair. At least they have in the past. These obstacles are starting to be removed, thanks to visionaries like award-winning British design engineer Tim Morgan, managing director of the Mountain Trike Company. He recognised this problem and decided to do something about it, designing what he claims to be the world's first, truly all-terrain, manual wheelchair, now in full-time production.

In order for the product to fit well with the end user's lifestyle, he set about designing a product that combined practicality and off-road capability. Using his skills as a design engineer and his passion for sport, he created the 'Trike', which has many high-end mountain bike components.

Time for change

The basic blueprint for wheelchair design has remained relatively unchanged for the last 100 years (discounting updates in the materials used). Two larger wheels are located at the back--allowing users to propel themselves by pushing the wheel and two smaller castor wheels are located at the front for stability. Whilst this creates a stable and comfortable ride on smooth surfaces, it makes it almost impossible to move the wheelchair across uneven, muddy or steep terrain. Even when pushed by a companion, the lack of suitable suspension and tyres means that the ride is extremely uncomfortable and the wheelchair is liable to get stuck.

In recent years, attempts have been made to adapt the wheelchair design for use off-road. These designs usually incorporate the standard wheelchair platform but include mountain bike style tyres or suspension.

This still makes self-propulsion awkward, as the wheel rims quickly become dirty and slippery. Steep hills are also hard to negotiate without tipping backwards, due to a lack of rear stability.

In contrast, the Mountain Trike has been completely re-designed from the ground up and resembles a high-end mountain bike more than it does a traditional wheelchair. What makes this all-terrain wheelchair special is how it is made and some features are customisable. The key innovation design feature is a unique lever drive system that allows the user to power, steer and brake the Trike by using two levers that are positioned in front of them and, importantly, keeping the user's hands clean and dry in all weathers.

High-end blend

The levers are connected to the wheels using similar technology to that found on a mountain bike and power each wheel independently. A third wheel at the back stabilises the chair and can be steered using a joystick mechanism attached to one of the levers. A highly ergonomic adjustable chassis was developed from user feedback and optimised for strength to weight ratio. Independent air suspension enables travel over rough and uneven ground in comfort and safety, and hydraulic disc brakes give all weather control. This blend of high-end components, precision UK manufacturing and innovative design features has had an excellent response from the market.

This revolutionary product has won a number of accolades, including University of Bath Design awards and several 'Best new product of the year' awards at various UK mobility shows, in 2013, Morgan was awarded the RAE Silver Medal for 'outstanding contribution to British Engineering and Commercialisation' and in 2014 he was nominated for the SEMTA Skills awards 'Engineering Hall of Fame', alongside several other prestigious engineers.

In order to develop the Mountain Trike All Terrain wheelchair, four cycles of design iterations and prototype builds where implemented and managed by Morgan, using CAD and CAM techniques. With the core focus on 'User Centred Design', these prototypes were tested with wheelchair users and feedback included in the design. This systematic design and product review process led to a highly optimised product, focused on the wants and needs of the end user. Design inspiration was taken from his own love of mountain biking and integrated a significant level of high-end bike technology into the Trike's design.

This led to an outstanding product, with a far more positive image than many other mobility aids. It was then taken forward through official validation and certification, in order to gain the CE mark, while also filing and securing two approved patents, with two more pending.

Recently, Morgan has added two new all-terrain product designs to the Mountain Trike range--the MT Push and the MT Evo. The MT Push, a buddy chair, has very similar design features to that of the Mountain Trike, but Morgan has replaced the lever drive with a removable adjustable push handle located behind the user, which is where the steering and braking takes place by the rider's buddy and adjustable armrests have been added for rider comfort. From a technical point of view, the MT Push features a strong, yet lightweight, aluminium chassis to cope with rough terrain, air suspension for a comfy ride and hydraulic disc brakes for exceptional all-weather control. Hand rims have been added for rider safety and the ergonomic adjustable seat can be adaptable for special requirements.

The third product design Morgan has been working on is the MT Evo, which is a Mountain Trike adapted for riders with limited hand function and therefore would find it difficult to operate the lever drive system. The MT Evo has the same excellent all-terrain performance to that of the Mountain Trike, but a simpler control mechanism.

The brake handle has a straightforward pivoting handle, which operates the disc brakes by moving your arm inwards and, when using a gripping aid, the system requires no finger function to operate. The unique direct steering means that the rider can steer and drive the Trike with only one arm--pivot left to go left, right to go right--with this simple steering giving excellent control for a smooth turn and an easy ride across slopes.

An ergonomic loop provides an easy-to-use method to drive engagement. And, as with the design of the other Trikes, the MT Evo also has disc brakes for first-rate all-weather control, and air suspension for comfort and safety.

Mountain trike in action

With the Mountain Trike Company trading since August 2011, selling direct to worldwide customers from its UK premises, wheelchair users from around the globe are benefiting from the revolutionary wheelchair designs, such as Laura May. She was a typical child who loved the outdoors--climbing trees, riding her bike--but was left paralysed following an operation to repair her scoliosis (abnormal twisting and sideways curvature of the spine).

"I was amazed at the technical ability of the Trike," she recalls. "For the first time in eight years, I actually felt 'that feeling' again of being able to roll fast, down difficult terrain, and just enjoy it! It works my arms and, the more you ride it, the better skills you get. It's a hard-core piece of fun that gets mountain bikers, no matter what ability, drooling onto their handle bars--I love my Trike!"

Then there's Jordan Fielder, who broke his back dirt biking and thought his adventurous days of exploring trails and being in the outdoors were over. "I discovered the Mountain Trike while researching off-road wheelchairs while in hospital and rehab," he says. "There is nothing else in the world that has the design features I was looking for and the versatility of the Mountain Trike. We live in British Columbia, Canada, on Vancouver Island. There are so many trails and scenic locations that a regular wheelchair could not get to. Since my Trike has arrived, I've been able to explore the wilderness together with my family. My fitness has improved greatly since I've been using my Trike; it exercises a whole different group of muscles, compared to pushing a standard wheelchair."

Sustainable business

Meanwhile, Tim Morgan has taken on the challenge of turning his engineering project into a sustainable business. He continues to custom-build each product, even offering customers their choice of colour frame from the extensive range. But he doesn't intend to stop there -already he has plans for a geared version and is working on designs to see if it is possible to fit a small battery pack to the Trike. This one, it seems, is the wheel deal.

Web: http://www.mountaintrike.com Email: info@mountaintrike.co.uk T: +44 (0)1270 842616

DESIGN APPROACH

Tim Morgan's starting point was to adopt a 'User Centred Design' approach to the development of the Mountain Trike. This was seen as essential to the process, as he is not a wheelchair user himself, so it was vital that he consult a wide range of end users to gain their feedback and ensure the Mountain Trike was ideally suited to their wants and needs.

A systematic, iterative approach of design, prototype, end user testing and design update was completed, encompassing four key stages. The first prototype was constructed by Morgan as part of his final year Masters project in Innovation and Engineering Design at the University of Bath. This prototype proved the main design principles and gained excellent feedback from local wheelchair users who tried it. This gave sufficient motivation to take the project further and, with a business mentor, he endeavoured to set up the business to take the Mountain Trike to market.

At the second prototype phase, a manufacturing partner was secured and they made five Proto 2 units, tested by hundreds of wheelchair users. Four Proto 3 units were constructed and used for CE testing and certification, in addition to marketing and user tests. The final iteration was the production model, which has had further optimisations and small improvements made throughout the last four years of Mountain Trike production, with the company maintaining the core beliefs throughout of User Centred Design.

MOUNTAIN TRIKE STATS

FRAME:                                                 Aluminium Frame

SUSPENSION:                             Rock Shox monarch R Air shocks

BRAKES:                     All-weather Avid DB1 hydraulic disc brakes

STEERING:                    Direct control, cable-operated rear wheel

FOOTREST:                     Adjustable height footrest, flips up for
                                                   transfer, removable

SUPPORT:                             Moulded comfort cushions, tension
                                             adjustable support straps
                                      foot straps, option for seatbelt

LENGTH (FULLY ASSEMBLED):                                        132cm

SEAT WIDTH:                                                       17in

SEAT ANGLE:                 20 degrees 'bucket' for comfort and safety

SEAT CUSHION:                      Removable foam cushion (Size 40cm),
                                           wipe clean polyester fabric

SEAT HEIGHT FROM GROUND:                                        46.5cm

SEAT LENGTH:                                               44.7-48.7cm

FOOTREST HEIGHT:                    Max foot rest height--41cm to 48cm

MOUNTAIN BIKE WHEEL SIZE:                                        24 in

OVERALL WIDTH:                                                    74cm

WEIGHT:                                                           20kg

BACK HEIGHT:                         37cm (also adjustable forwards or
                            backwards), higher seat backs available on
                                                request, no extra cost

FOR TRANSPORT:                   The seat back folds flat and the rear
                              wheel folds underneath the frame--length
                                         is reduced from 132cm to 82cm

RIDER:                        Maximum weight 100kg; maximum height 6'4
COPYRIGHT 2015 Institution of Engineering Designers
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Title Annotation:TRIKE TRIUMPH
Publication:Engineering Designer
Geographic Code:4EUUK
Date:Nov 1, 2015
Words:1784
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