Operating instructions

3
MASTS
GENERAL INFORMATION
Telescopic masts are considered to be temporary structures and should not be
expected to withstand all weather conditions indefinitely. The table on page 4
specifies the wind speed that each mast will withstand. For wind speeds in excess of
those stated it is essential for the life of the mast and the safety of the operating
personnel, to retract the mast.
Pneumatic masts operate at low pressures, normally between 1kg/cm and1.75kg/cm
(14 and 25p.s.i.)
DO NOT operate at pressures above those recommended for the type of mast in
use. The mast may not only be severely damaged but injury could occur to
personnel. Any mast requiring higher air pressures or utilising compressor equipment
not supplied by the mast supplier/manufacturer should be referred back to us for
consideration and advice.
Since telescopic masts are essentially composed of sliding sections, care should be
taken to keep them clean and lubricated (see Maintenance section).
Hilomast pneumatic telescopic masts are constructed from heat-treated aluminium
alloy tubing. Each tube is fitted with a piston that incorporates a neoprene lip seal
and a PTFE slide ring. The upper end of each tube is fitted with a guide collar that
also incorporates a PTFE slide ring. Attached to the upper side of each collar there is
a locking collar fitted and clamped by means of a thumbscrew. These thumbscrews
are fitted on alternate sides of the mast to give maximum operational clearance. For
conditions where more clamping power is required or where the thumbscrews are
considered to be an obstruction for the feeder cables, it is possible for these
thumbscrews to be replaced with socket head cap screws. These can be tightened
with a 6mm Allen key. All the parts necessary for both methods of clamping the
collars are supplied with each mast.
All masts, with the exception of the NY series, have a base piston spigot diameter of
76mm and all mounting arrangements should be based on this size. All masts,
except the NY series, have inlet and exhaust ports at ¼” BSP. The NY series ports
are tapped 3/8” BSP.
Masthead spigots for all masts, with the exception of the NY series, will be 150mm
long x 51mm diameter, except where specified.
If U-bolts and clamps are used to fasten antennas directly to the top section of the
mast, DO NOT over-tighten as this can damage the keyway. BR series masts have a
flange which is a 6” x 5-½” x ½” thick rectangular plate secured with one quick
release pin. It can be drilled to suit customer’s requirements.
Long Duration Storage
If possible, store in an upright position to prevent seal distortion (see Maintenance
section)