Crane Bridge

pendent control operator can comfortably negotiate

in a work area, approximately 750 mm/s 150 ft/min.

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The crane shall have the following rated load speeds (plus or minus 15

percent):

a.

Hoist - high speed of [75 mm/s] [15 feet per minute (fpm)] [_____]

b.

Trolley - high speed of [250 mm/s] [50 fpm] [_____]

c.

Bridge - high speed of [250 mm/s] [50 fpm] [_____]

2.1.5

Crane Bridge

2.1.5.1

Crane Bridge Girder

Provide a patented track for the crane bridge girder. The summation of all

normal stresses on a girder section under analysis shall not exceed the

allowable stress for tension or compression.

2.1.5.2

Bridge End Trucks

The wheel assemblies for the crane end trucks shall be the swiveling type

so that connections between the end truck and the wheel assemblies shall

have rotational movement in two axes. Further, these connections shall

ensure contact of all end truck wheels with the runway operating (lower)

flange at all times. End truck wheels shall be hardened to a minimum

hardness of 375 BHN, and have flat treads with side guide rollers.

2.1.5.3

Bridge Brake

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NOTE: Select "100 percent" for an outdoor crane,

"50 percent" for an indoor crane.

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Provide bridge drive with an electro-mechanical brake. Provide brake a

minimum torque rating of [100][50] percent of the drive motor rated torque

and adjustable down to 85 percent of its torque rating. Select disc brake

(if applicable) having housing which permits easy access for wear and

setting inspection of the friction discs.

2.1.5.4

Bumpers

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NOTE: Select "spring" type bumpers if bridge speed

is 250 mm/s 50 fpm or slower; otherwise, select

"hydraulic" type bumpers.

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Provide elastomeric type bumpers on the trolley. Provide [spring or

elastomeric][hydraulic] type bumpers on bridge end trucks.

2.1.6

Hoist Trolley

The wheel assemblies for the hoist trolley shall be the swiveling type so

that connections between the trolley and the wheel assemblies shall have

rotational movement in two axes. Further, these connections shall ensure

SECTION 14637N

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