Snorkel MB20N-sn0001-0131 - Manual (Page 2)

Introduction
MB20N/MB26
SCOPE
This manual includes the procedures and
responsibilities for the inspection, transportation,
preparation and safe operation of the MB20N &
MB26 Work Platforms. The Maintenance & Spare
Parts Manual covers preventative maintenance and
trouble-shooting. The term MB20/26 is used
throughout the text of this manual.
MB 2O/26 PURPOSE & LIMITATIONS
The purpose of this machine is to provide fast and
safe access to difficult-to-reach areas. The machine
may be used only on firm and level ground. Refer to
the Specifications section at the back of this
document for the machine’s parameter and access
limitations.
DO NOT use on soft ground or on slopes greater
than 2 degrees .
DO NOT use the lifting mechanism to raise or lower
goods or persons except within the cage and subject
to the weight limitations.
DO NOT enter the platform from a structure, rack or
other platform.
PLATFORM
The MB20/26 is a self propelled, fast acting aerial
work platform, designed to raise persons to a plat-
form floor height of 6.00 m (~ 20 ft.). The accessible
height however is approximately 8.00 m. The plat-
form upper payload limit is 215 kg. The unit offers the
ability to reach over obstacles but must be used on
firm and level ground. The platform is large enough
for two operators and has a free-draining perforated
floor with 150 mm toeboards. Hand-rails are con-
structed from aluminium alloy tubing and a safety
drop-bar is provided at the entrance. Safety harness
anchor points are also fitted in the floor of the plat-
form.
UPPER CONTROL BOX
The upper control box or primary control box is fitted
to the front of the platform. It features a Joystick
which provides proportional control from zero to pre-
programmed maximum for all functions including
drive and steer.
A safety Interlock Switch or ‘deadman grip’ is
incorporated into the Joystick . It must be activated at
all times in order to operate any function. This feature
allows for one-handed operation. A complete
explanation of control functions can be found in the
section headed ‘Operation’.
LOWER CONTROL BOX
The lower control box or secondary control box is
fitted to the mast cover at arm level. It features a
deadman toggle switch and selector toggle switches
to provide pre-programmed speeds for all functions
except drive and steering. This control station is
used primarily for service-type operations including
pre-operation inspection. It should never be used to
position a manned or unmanned platform. It may be
used in the event of emergency, however, to lower
the manned platform.
ELEVATING ASSEMBLY
The platform is raised and lowered by a combination
of jib and telescoping mast actions. The main
hydraulic cylinder, mounted within the masts, lifts the
first mast directly. The other masts are connected by
a system of heavy duty plate chains and pulleys to
ensure sequential lifting. A parallel system of heavy
duty straps ensures that the masts descend in the
proper sequence and also ensures that any one mast
cannot be held in suspension by an obstacle during
descent.
The jib cylinder provides a lifting arc to the jib and
platform. All hydraulic functions are carried out using
remote solenoid-operated control valves. Each
cylinder features an integral holding valve to prevent
uncontrolled descent in the case of a hose burst.
ROTATION GEAR
The complete mast, jib and platform can be rotated to
provide up to 2.6 m (8.5 ft.) of working outreach. This
dimension is measured from the centreline of
rotation. Rotation is carried out by means of an
integral hydraulic motor driving a worm drive unit
about a heavy duty slewing gear.
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