Tamara was a student at a well know centre of excellence for the conductive education of children with Cerebral Palsy. She was 19, and had severe learning and physical disabilities. She was obese and required hoisting for all transfers – a factor which makes Tamara such an interesting case study.
Physiotherapists Dee and Danny have given us some challenges, but Tamara’s was going to push the limits, even for the Tomcat. I promised to “think about it” but had little idea where to start.
The problem was Tamara’s weight, build, and lack of self support. I wasn’t concerned about the Tomcat frame being strong enough – it’s been tested to a quarter tonne without flinching, the problem was her total reliance upon the backrest which is conventionally supported on the slender seat post by which you adjust saddle height. Even ignoring the strength issues of this component, there’d be the inevitable flexing and sway which would be alarming for her. As if that wasn’t bad enough there was the familiar problem associated with hoisting, namely the backrest getting in the way of operations whilst the rider is being hoisted on.
John and I threw ideas about on the way home and it wasn’t just the gearbox cogs that were turning, but by the time we hit Gloucester; I’d something resembling a plan to put to Dee and Danny.
The requirements were as follows and we needed to design:
- A very rigid trunk support, both lateral and mid-line
- The support to be adjustable for height, depth and tilt
- The support must move clear of the hoisting area during hoisting
- It must have a “memory” to return to its set position after hoisting
- It must have a quick release system for easy transport
- It must be interlocked for safety
- And trickiest of all, it must not collide with the Carer Control system during operation
Though we left the saddle supporting Tamara’s body weight in the usual way; I needed an alternative support for her trunk for the reasons given. The stiffest part of any trike is its rear axle bearing housings, so I decided to support an “A” frame with a trombone slide at those points. The concept was simple. An “A” frame would tilt – front to back – from quick releasing mountings on the bearing housings, and the trunk support it carried, would slide up and down on trombone slides.
The latch/adjustment mechanism however, was complex. It needed to have fine adjustment for backrest depth, a quick tilt mechanism for moving clear when hoisting, and safety interlocks to protect it from accidents. As if that wasn’t bad enough it too needed a quick release, so the whole trunk support system could be removed for transport. Just to make matters worse all this tilting, releasing and adjusting had to avoid the Carer Control system that would inevitably be required with such a trike.
It was difficult and took months of design time and three prototypes before we got it right, but we did get it right, and Tamara got a trike she could access and transport easily. You’d be amazed how well she did once she was well seated on a trike stable enough to win her confidence, and was able pedal herself – an achievement that took even Dee and Danny by surprise.
I am very proud of the Tamara. Not just for overcoming the engineering puzzle – though that was fun – but because I know there are many obese children and adult hoist users like Tamara whom we can now help.
This new trike has pushed the limits of what is achievable for obese hoist users, just as Carer Control pushed the limits of what was achievable for kids like my Thomas who had learning difficulties. Carer Control allowed him, and many other children since, to explore the countryside in complete safety. Hopefully the Tamara will give obese hoist users their very first chance to use their body as nature intended, and just imagine what a thrill that must be!
Bob Griffin
