Health and safety in motor vehicle repair and associated industries

Figure 29 Wall-mounted
inflation cage (photograph
courtesy of ATS
Euromaster Ltd)
Figure 30 Clip-on chuck for
tyre inflation
Health and Safety
Executive
143 During inflation the operator should not stand in the likely trajectory of the blast
even when using a restraining device because they reduce but do not eliminate
the risk. Airlines should be long enough (see paragraph 140) with quick-release
couplings (see Figure 30) at both ends to allow the tyre to be deflated from outside
the likely explosion trajectory if a fault (eg a potential ‘zipper’ failure of the sidewall)
is suspected.
144 The pressure gauge/
control valve should
never be jammed in the
open position, nor should
‘unrestricted’ airlines
(ie without a gauge or
pressure control device)
be used to inflate any
tyre. For bead-seating of
large commercial tyres,
removing the valve core
allows faster inflation
without using excessive
pressure. Alternatively,
using a ‘bead blaster’
device may be helpful
when seating the tyre
bead. Airlines attached to
tyres should never be left
unattended or connected
long-term as air seepage
may overinflate the tyre.
Split-rim wheels
145 Serious accidents,
including fatalities, have
been caused by the violent separation of split-rim wheels. They are becoming
less common but may be encountered on older vehicles as well as military trucks,
fork-lift trucks, cranes, scooters, caravans and wheelbarrows. They are also used
for some off-road vehicles (because they allow the tyre to be removed without
specialist equipment). Tyre removal/inflation should only be undertaken following the
precautions set out below, which are in addition to those for car tyres.
146 There are two basic types of split-rim wheel assemblies:
n
n
multi-piece wheels; and
divided wheels.
Multi-piece wheels
147 This category includes large commercial wheels. The most common types are:
n
n
n
the two-piece wheel (see Figure 31). A split-spring flange is fitted to a groove in
the side of the wheel rim (known as the gutter groove) using levers. No locking
ring is used;
the three-piece wheel and four-piece wheel (see Figure 32). An endless flange
and split locking ring are sprung into the gutter of the wheel rim using levers.
Four-piece wheels use two endless flanges;
demountable rims (see Figure 33). This is a three-piece, collapsible rim in which
the disc is created by short spokes forming part of the hub.
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