Trolley Drive

contact of all hoist trolley wheels with the crane bridge operating (lower)

flange at all times.

Hoist trolley wheels shall be hardened to a minimum

hardness of 375 BHN, and have flat treads.

2.1.6.1

Trolley Drive

Provide motor-driven trolley.

2.1.6.2

Trolley Brake

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

"50 percent" for an indoor crane.

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Provide trolley drive with an electro-mechanical brake. Provide brake with

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.

2.1.7

Hoist

ASME HST-4, Class H3, except as modified and supplemented in this section.

2.1.7.1

Load Block

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NOTE: Include sentences for custom design load

block with trunnion if requested by using activity.

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NOTE: Include sentence for safety latch on hook if

requested by using activity.

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Construct the load block entirely of steel. The design shall preclude the

wire rope from being cut, pinched, crushed, or chafed in case of

two-blocking.

[Provide load block with a trunnion separate from the sheave pin. Bore the

trunnion for swivel mounting of the hook and securely retain in the block

side plates. The trunnion shall rotate about its horizontal axis in holes

bored in the side plates.]

Construct the load block so that the hook and hook nut may be removed from

the load block without disassembly of the block. Hook and hook nut shall

be forged from steel conforming to ASTM A 668/A 668M. [Provide the hook

with a safety latch.]

Provide the equalizer bar or sheave perpendicular

to the running sheaves. Mark hoist capacity in pounds on both sides of the

load blocks.

Hook and hook nut shall be capable of complete disassembly that enables

access to all surfaces of hook, including shank and hook nut for inspection

purposes. Provision shall be made for the hook nut, or other hook-to-block

fastener, to be keyed to hook shank by means of a set screw or similar,

easily removable, securing device.

SECTION 14637N

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