Usage instructions LITTY 4all & 4you
24
19.2 Caster wheels flapping
Uncontrolled swivelling backwards and for-
wards of the caster wheels around their axes
on the caster fork (while moving) is known as
"fluttering".
If the caster wheels start to flutter, imme-
diately reduce your speed to prevent the caster
wheels from jamming sideways and therefore
reduce your risk of falling.
The
speed limit
at which caster wheel flutter-
ing starts,
is reduced by
:
increasing size of the caster wheels
increase weight of the caster wheels
falling load on the caster wheels
decreasing caster length of caster wheels
The following options are available to
counter-
act caster fluttering generally
:
Fluttering can be reduced by
reducing the
caster wheel diameter
. This means in-
stalling a small caster wheel in a different
wheel position in the caster wheel fork
(seat height thus remains the same) would
be one way of reducing fluttering. How-
ever, please note that using a smaller
caster wheel makes it more difficult to
overcome obstacles and makes tipping
necessary more often. The smaller the
caster wheel is, the more driving skill is re-
quired.
Another option for reducing fluttering is to
use a
lighter caster wheel with the same
diameter
or, as described above,
with a
smaller diameter
.
Figure 45: Caster length
It is also possible to
increase the caster
length
. The caster length is the distance
between the rotary axle of the caster wheel
fork projected onto the floor and the wheel
contact point. The wheel contact point of
the caster wheel trails behind the rotary
axle, so to speak. The caster length has a
stabilizing effect on moving in a straight
line. Increasing the caster length can be at-
tained by mounting the caster wheel in a
different wheel position on the caster
wheel fork (the in doing so, the front seat
height or the angel of the seat changes,
see chapter 17.1).
19.3 Replacing the caster wheel forks
A distinction needs to be made between the
caster wheel forks with a screwed axle and
those with a quick-release axle.
19.3.1 Caster fork with screwed axle
The following instructions are intended
for and may only be carried out by a rehabilita-
tion specialist dealer or PRO ACTIV
The
caster wheel fork with a screwed axle is
removed
using a wrench which is included in
the scope of delivery. This wrench is inserted
into the two holes on the nut of the caster
wheel bearing block and turned anti-clockwise,
e.g. using an AF 24 mm fork wrench. The
caster wheel fork needs to be held still. When
Caster wheel
for rotary axle
Caster length
Wheel contact point
