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Work
Station Crane Terminology
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Axial
Load:
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The total
vertical force applied to the supporting structure. |
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Formula:
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Axial load
= (overall weight of the crane) + (design factor x weight of load) |
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Boom:
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The horizontal
track of a Work Station Jib crane, in which the hoist trolley rides, which
rotates about the pivot. |
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Bridge
Length:
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The overall
length of a bridge. Note: The Working Length or Hook Coverage of the bridge
is less than the overall bridge length. |
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Buffer
Assembly:
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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. |
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Column:
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The column
of a free standing bridge crane is one of the "legs" on which
the crane stands, and is made of square tube. |
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Deflection:
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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, L/320 for wall mounted work station jibs, and L/200 for free standing
work station jibs and L/450 for aluminum work station jibs (AL100), where
L= support center distance or span. |
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Header:
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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. |
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Overall
Height (OAH):
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The distance
from the floor to the top-most point on a crane (should include hardware).
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Span
(of Bridge):
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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. |
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Formula
(for most cranes):
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Span =
{OAL bridge - (2 x bridge cantilever dimension)} |
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Support
Center:
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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. |
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Supporting
Structure:
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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. |
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Trolley:
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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. |
