User manual of Tilty
page 20 of 43
7.2 Alteration of the centre of gravity’s position
Fundamentally, Tilty’s centre of gravity is situated in front of the wheelchair’s rear
axles. The distance between centre of gravity and rear axles is decisive on the
handling and the safety of the chair. If the axles are right behind the centre of
gravity, the child will wheel and manoeuvre much easier, yet the danger of
overturning increases, above all if the chair is tilted!
This is why you will have to concentrate on the seatback’s maximum inclination angle
each time the wheel position is changed, i.e. on the situation as both the seatback is
folded down in the maximum position and the seat-unity is tilted.
For testing the overturning stability, you should in any case activate the supporting
wheels and a strong, experienced assistant should help you.
The centre of gravity must be adjusted so that with the maximum inclination angle and
with the original load the supporting wheels are not reaching the ground.
The wheel base lengthening enables you to shift Tilty’s centre of gravity backwards by
100 mm and to increase the overturning security. However, this will also increase the
turn radius.
7.3 Critical height of obstacle
Tilty’s critical height of obstacle, with an activated supporting wheel is at the best ca.
2.5 cm.
7.4 Static stability
Tilty’s static stability is 4°, i.e. ca. 7%. On steep slopes, the wheelchair together with its
occupant may tilt over and your child may be injured badly!
Safety precautions:
Fundamentally, your child may turn over backwards in its wheelchair as it is getting
over an obstacle. This depends on the wheelchair’s centre of gravity and on the
height of obstacle. Please always make sure that an assistant is helping and
safeguarding the child as it wants to get over high obstacles, e.g. stairs and thresholds.
Advice for your orthopaedic mechanic engineer:
On trying out different positions of the rear wheels, use the supporting wheels on your
first trials and test the behaviour of the centre of gravity at best together with a strong
helper who will safeguard your tests. Please also pay attention to the changed situation
as the wheelchair is in its tilt-position.
