

Axial
Load:
The total
vertical
force applied
to the
supporting
structure.
Formula:
Axial load =
(overall
weight of the
crane) +
(design
factor x
weight of
load)
Bridge
Length:
The overall
length of a
bridge. Note:
The Working
Length or
Hook Coverage
of the bridge
is less than
the overall
bridge
length.
Buffer
Assembly:
A floating
spacer that
rides in the
runway
between two
bridges (or
hoist
trolleys) to
prevent a
concentrated
overload
between
hanger
points. It
physically
separates the
bridges or
trolleys a
minimum
distance
apart.
Column:
The column of
a Free
Standing
Bridge Crane
is one of the
"legs" on
which the
crane stands,
and is made
of square
tube.
Deflection:
The
difference in
elevation of
the track
between an
unloaded
crane and a
fully loaded
crane;
usually
measured in
inches.
Typical
Gorbel®
designs are
L/450 for
bridge
cranes, where
L= support
center
distance or
span.
Header:
The
horizontal
member of a
Free Standing
Bridge
Crane's
support
structure,
made of two
back-to-back
channels,
from which
the runways
are hung.
Overall
Height (OAH):
The distance
from the
floor to the
top-most
point on a
crane (should
include
hardware).
Span
(of Bridge):
The distance
between the
center line
of the
runways. The
span must be
distinguished
from the
Overall
Length (OAL)
of bridge,
which is
larger than
the span.
Formula (for
most cranes):
Span = {OAL
bridge - (2 x
bridge
cantilever
dimension)}
Support
Center:
The distance
between the
center line
of the two
support
columns or
hangers along
a runway.
Note that
support
centers
determine
what track
style is
required.
Supporting
Structure:
For a Free
Standing
Bridge Crane,
the
supporting
structure
refers to the
support
assembly,
also called
the Goal Post
or End Frame,
consisting of
the columns
and header.
For a Ceiling
Mounted
System, the
supporting
structure is
the ceiling,
including
trusses,
stringers,
columns,
etc., from
which the
crane is
hung.
Trolley
Saddle
Height(TS):
On a Free
Standing
Bridge Crane,
this is the
height from
the top of
the saddle of
the hoist
trolley (the
clevis pin
from which
the hoist is
actually
hung) to the
floor.
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