50 Years Ago
NSC 31
Jun 20
Insulated cladding being
fixed to the side. The
outer layer consists of
Colorsteel PVC coated
galvanised steel sheet
the tops of the frames together but also acts
as the support for the lightweight concrete
roof slabs.
There are 17 levels of pallets each of which
can weigh 1 or 2 tons. Five types of pallet are
stored, three are large and weigh 1 or 2 tons,
while two are small and weigh 1 ton. The small
pallets are stored side by side in the same
space as occupied by one large pallet but
since they cannot span the distance between
the cantilevered pallet bearers they can only
be accommodated in spaces provided with
support grillages which occur at three levels.
Cantilevered brackets are provided in
ordered to keep the height of the building
to a minimum by recessing them into the
underside of the 8 in × 3 in channel pallet
bearers. This system enables the crane forks
to operate within deeper clear vertical spaces
than would be the case with cross beams.
The only interruptions come from lateral
restraints which are connected to the spine
bracing which resists longitudinal wind and
crane buffering loads. For efficient working,
tolerances had to be very fine for structural
steelwork and were ⁺₋⅜ in. in any horizontal or
vertical plane for height, width and length of
the building and local deviation not to exceed
⁺₋⅛ in. in 20 ft. This degree of accuracy led to
the decision to employ bolted construction to
avoid any possible difficulties from distortion
caused by welding. High strength friction grip
bolts were specified but as they were difficult
to obtain in ½ in diameter size it was decided to
use Huck Bolts for shop fabrication while the
½ in HSFG bolts were employed on site with
load indicating washers. The stacker cranes
themselves are considerable structures as
they have to pick up two tons and be capable
of placing it at any height up to nearly 100 ft
and to place it accurately.
The crane consists of two 160 ft high masts
connected together at the top and bottom
and running on a single flat bottomed rail.
Overall height is 109 ft. The top is restrained
by horizontal guide wheels running on either
side of a rail on one side of the aisle, while
the bottom is retrained by horizontal wheels
running against the rail. The lift platform
moves between the masts while the pick-up
forks can exit left or right. Total weight of each
crane is about 30 tons and there is one to each
of the seven aisles. They may be operated
manually, by punched cards, or by computer.
Maintenance is required at ground level for the
motors and running gear and at a high level
for the guide wheels for which a number of
platforms, reached by stairs, are provided at
101 ft level.
As yet a young industry in the UK there
is no doubt that Highbay storage is going
to be more essential as land becomes even
more costly and as storage itself becomes
increasingly computerised. This is a highly
specialised business where expertise in
materials handling is vital to success. With its
many years of experience in this specialized
field Dexion should be well to the fore in this
important business.
Goods delivery and collection area
The system of racks and aisles is
shown in this picture taken during
the early stages of construction
East elevation showing bracing bays
Plan showing
extent of racking