Snorkel MB20J, Operator'S Manual

Page: 9 / 32

1. Introduction
1 - 2
PLATFORM
The MB20 / 26J platform is large enough for two operators indoors, one outdoors and has
a free-draining perforated floor with 150 mm toeboards. Hand-rails are constructed from
Steel tubing and a safety drop-bar is provided at the entrance. Safety restraint harness
anchor points are also fitted in the floor of the platform. These must be used at all times.
The main controls are fitted to this platform.
PLATFORM CONTROLLER
The primary (Upper) control box is permanently fitted to the front of the platform. It features
a joystick which provides proportional control for raising or lowering the mast, raising or
lowering the jib or rotating the complete mast assembly. The same joystick is also used to
drive and steer the machine.
A safety Interlock Switch or ‘deadman button’ 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 comprehensive explanation of control functions is given in the Operators
Manual - a copy of which shall be located in the platform document wallet located just
beneath the upper control station in the platform.
The secondary (Lower) control box is fitted to the mast cover at arm level. It features a
‘deadman’ enable button and selector buttons 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 a steel jib and a series of
telescoping mast sections. The main hydraulic cylinder, mounted within the masts, lifts the
2nd 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 ensure that a mast cannot be held in suspension by an obstacle during
descent.
The jib cylinder provides a lifting arc to the jib and cage assembly. All hydraulic functions
are carried out using solenoid operated control valves. Each cylinder features an integral
holding valve to prevent uncontrolled descent in the case of a hose bursting.
!
!
DO NOT use the work platform without guardrails properly
assembled and in place.
W A R N I N G
!
!
NEVER
operate the machine from the upper controls until the
platform entrance drop-bar is in the fully lowered position and the
safety harness is fitted.
W A R N I N G