Requirement: to create a lightweight, portable, easily stored electrically powered all terrain mobility solution for a quadriplegic rider.
Every mobility solution is a result of compromises made during the design process between different performance and functional criteria. These compromises are made on the basis of the design specification generated from user requirements, regulatory requirements, manufacturing restrictions and so on. Perhaps the user needs the mobility solution to operate indoors, negotiate narrow doorways and provide access to upper kitchen cabinets. The resulting solution will hopefully be very good at meeting these needs, but likely at the expense of outdoor performance. Perhaps the market determines a maximum retail price and so the solution fit and finish may not be as polished as could be achieved with more expensive materials and processes. In short, each mobility product is the answer to a specific set of questions rather than a single solution for everything.
Key specifications for this project were;
The resulting mobility solution is based on an ICE Trike chassis, complete with the “Compact Twist Fold” mechanism and front elastomer suspension, all purchased second-hand. The CTF system allows the chassis to fold in half for storage and transport similar to the Hase Kett trike.
20″ cycle trials rims were matched with high-volume BMX tyres onto the existing disc brake hubs for the front wheels. A Heinzmann geared hub motor, complete with disc rotor mounting was laced to a Nimbus 26″ 42 mm wide double wall box section rim to make up the rear wheel. Unfortunately the direction of motor rotation requires a right sided brake caliper mount which had to be made (thanks to PT). The motor came with the standard Heinzmann battery, battery pannier and control electronics also mounted thanks to PT) and twist grip throttle.
The seat frame base was lengthened to accommodate a pressure relief cushion and fitted custom back and base upholstery (thanks to Covers Plus). The standard ICE Trike “bottom bracket” was modified to become a foot rest similar to those used on sport recumbent hand cycles.
A key feature of the trike is the control system for motor power and braking. The user moves both hands forward’s to apply the brakes and pulls both hands backwards to activate the motor and accelerate. The handlebar assembly is turned either left or right to steer.
All-terrain capability is sufficient to access forest tracks and trails and the chunky tyres, long wheelbase and front ICE elastomer suspension provides a comfortable ride. The trike meets all specifications for the project in terms of lightweight, storage, transport and accessibility.