Principal Investigator
Other Investigator(s)
Project Abstract/Overview
Progress and Outcomes

John Noiseux

Mike Rosen
Richard Keller

Project Abstract/Overview

The Magic Walker was designed at the University of Tennessee . It is a gait trainer / walker device that provides a child with support in the upright standing position. The child's weight is partially born on the walker seat and partially supported by the child's legs. The amount of support received can be customized based on the needs of the child. Steering of the walker is achieved by flexion of the trunk laterally. The mechanical coupling of steering to lateral trunk flexion leaves the upper limbs free for other tasks or for the child to stabilize himself / herself. The utilization of lateral trunk flexion, in contrast to rotation, is what most clearly distinguishes this design from other gait trainers / walkers. The main objective of the Magic Walker Brake Development project is to incorporate a brake system into the present design of the walker. This will enhance safety and may increase the marketability of the design. In particular, it will permit the Magic Walker to be used (with supervision) in an outdoor setting where inadvertent access to down slopes requires automatic activation of the brakes.

Progress and Outcomes

Year 3 (2002-2003) 

The split-caliper braking system identified in Year 1 has been successfully integrated into the Magic Walker design. Upon identifying the actual braking technique, various approaches to control the activation of the brakes were explored. These approaches included direct application of the brakes via a hand grip technique (i.e. traditional bicycle caliper brakes),some type of automatic application of the brakes when a certain pitch of the walker (fore-aft tipping of the walker) or speed was achieved; and mechanical linkage to the walker seat. A mechanical linkage to the seat was selected for several reasons.

The walker's seat mounting was successfully redesigned such that the seat is connected to the walker by a pivot at the front and by springs at the rear. The spring force supporting the rear of the seat is adjustable. When the seat is depressed (i.e. the child sits down on the seat) this motion operates the Magic Walker brakes through a mechanical linkage and brake cable.Because the spring stiffness is adjustable, the amount of support that the seat can provide without activating the brakes is adjustable. This will allow a parent or therapist to provide more support to children that can bear very little weight through their legs, while also allowing the brakes to be adjusted to encourage children with greater ability to support their own weight, to do so.Children who can support more of their own weightcan be discouraged from sitting down and propelling the walker like a ride-on toy by having the brakes become activated with less force applied to the seat.

The rationale for the seat/linkage system was that, in a situation where the walker was gaining too much speed (or the child was trying to ride it down a hill) the child would tend to either deliberately (as in riding scenario) pick his/her feet up off the ground or stumble (uncontrolled scenario) – either way placing his/her weight on the seat and activating the brakes. It was decided that this was a good balance between the complexity, maintenance, and reliability issues of a more sophisticated electro/mechanical system and the risks of an system that relied solely on the deliberate activation of the brakes by the user. Also, it avoids the need for batteries and battery replacement implied by braking designs based on sensors.