| Cantilever
Racks |
What
is a Cantilever Rack?
A cantilever Rack is a freestanding storage unit with
horizontal load carrying arms extending outward from a
single vertical column. The absence of a vertical support
on the outboard ends of the arms permits uninterrupted
storage of long lengths of material.
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| Cantilever
Rack is the ideal system for storing furniture, steel bars,
pipe and tubing, lumber and other long , heavy items that
must be kept off the floor...provides instant accessibility
to one piece or a full load. Forklift easily loads off and
on arms and bases. Being modular in nature, additional arms,
uprights and braces may be added as storage requirements change. |
Cantilever
Rack is comprised of three components:
These
components must be ordered in the appropriate quantities
and capacities. |
| Uprights
Uprights consist of a vertical column and a horizontal base
which is bolted to a column. A minimum of two uprights must
be ordered to form a storage bay. Each edge of the column
is punched vertically on 3" centers so it may be used
as a single or double sided upright depending on the size
of the base used. |
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Holes
are provided in the base to anchor the upright to the floor.
Uprights must never be attached to walls, columns or other
structures. |
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| Arms
Cantilever arms are the heart of the rack system. Proper
selection can make or break a successful storage plan. Shelving
offers straight arms (generally used for storing stable
loads such as lumber, steel sheets, cartons and skids) and
inclined arms (for cylindrical objects or loads that tend
to roll forward). Arms can be adjusted on 3" centers
up and down the upright and are available in lengths to
60" in a variety of capacities. Standard arm color
is gray. |
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Straight
Arm
Straight arms up to 48" long have a minimum pitch of
3/8"
per foot to compensate for deflection. 54" and 60"
arms have a minimum pitch of 5/8"
per foot. |
Inclined
Arm
Inclined arms have a pitch of 20 degrees or approximately
4.36" per foot. |
Hair
Pin Keeper
The hair pin keeper permits instant adjustability and is easily
inserted and removed for adjustment of arm height. Lips are
available ion all arms. |
| Brace
Sets
Cantilever arms are the heart of the rack system. Proper
selection can make or break a successful storage plan. Shelving
offers straight arms (generally used for storing stable
loads such as lumber, steel sheets, cartons and skids) and
inclined arms (for cylindrical objects or loads that tend
to roll forward). Arms can be adjusted on 3" centers
up and down the upright and are available in lengths to
60" in a variety of capacities. Standard arm color
is gray. |
| Standard
Brace Patterns |
| |
"2B"
Horizontal Brace Pattern
Used on 6' to 10' Medium duty uprights and 8' Heavy duty and
Series 2000 uprights. |
|
"3B"
Horizontal Brace Pattern
Used on 12' Medium duty uprights and Series 2000 uprights
and 12' x 14' X Series uprights. |
"4BX"
Horizontal Brace Pattern
Used on 15' to 20' Heavy duty and X Series uprights and all
structural cantilever rack. |
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"4BXX"
Horizontal Brace Pattern
Used on all 15' to 20' uprights when the brace length exceeds
84" centerline to centerline of upright. |
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Designing
a Cantilever Rack System
The key to a successful cantilever rack system is the answer
to one question: What is the product (load) being stored?
The answer must include the length, depth, height and weight
of the product. Once this data is ascertained it becomes
a simple matter to determine the required arms, uprights
and braces. |
A.
Determine the number and spacing of arms
The load must be supported by enough arms
to prevent load deflection. Deflection may cause damage
to the load being stored as well as the arms (figure A1).
To detect deflection, place the load over two wooden blocks
(to represent cantilever arms) as shown in figure A2.
If deflection is not present it is acceptable to use a
two are system as long as this does not create an overload
condition. If the load shows deflection use three blocks
as shown in figure A3 or four blocks as in figure A4.
IMPORTANT: The load should overhang the end arms
by one-half the distance from upright centerline to upright
centerline. Failure to observe this measure may cause
an overload condition on the arms.
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B.
Determine the length of the arms
The depth of the load should never exceed the
length of the arm. A 48" wide bundle of plywood requires
a 48" long arm, bundles of steel 24" wide require
a 24" arm and so on. Rated arm capacities may be seriously
diminished if proper loading techniques are not observed.
Figures B1, B2 and B3 illustrate correct and incorrect arm
loading. |
| |
| C.
Determine the height of the upright
When determining the height of the upright
it is important to consider the ceiling height, forklift
reach, sprinkler systems and other factors, such as local
building codes, that might effect the overall height.
The
height of the upright in figure C1 is determined by adding
the base height, the number of loads to be stored, the arm
thickness plus 6" clearance between the load and next
arm. Contact your Shelving sales professional for various
rack dimensions such as base height and arm thickness.
IMPORTANT:
the load placed on the base does not diminish the rated
capacity of the upright. Thus, the heaviest loads should
be placed on the base. |
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| D.
Determine arm and upright capacities
As previously discussed, each arm supports
an equal amount of the load's weight. By determining the
number of arms per level and dividing it into the weight
per level, the required arm capacity can be determined (see
example at right).
To determine
the required capacity of each upright, multiply the number
of arms per side by the load on each arm. In figure D1,
each arm holds 2500 lbs. Twelve arms per side times 2500
lbs. per arm equals 30,000 lbs., which when divided by three
uprights, results in a required minimum capacity of 10,000
lbs. per upright.
Note:
Total arm capacity must never exceed total upright capacity. |
|
| E.
Determine brace length
Brace length is defined as the horizontal
distance from centerline of upright to centerline of the
next upright.
For
more information, contact a Storage Specialist by e-mail
or call 1-800-637-9508
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