Hooks shall be single barbed and shall be made of forged steel complying
with ASTM A 668/A 668M. Hook dimensions shall be as shown. Hooks shall be
fitted with safety latches designed to preclude inadvertent displacement of
slings from the hook saddle. Painting or welding shall not be performed on
the hook. Hook nut shall be secured with a removable type set screw or
other similar fastener, but shall not be welded. Hooks shall be designed
and commercially rated with safety factors in accordance with MHI CMAA.
The hook shall be free to rotate through 360 degrees when supporting the
rated load.
2.3.3
Hoisting Ropes
Hoisting ropes shall be regular lay, preformed, uncoated, improved plow
steel, 6 by 37 construction, with independent wire rope core. Ropes shall
be suited to meet the service requirements. Rope socketing or U-bolt clip
connections shall be made in accordance with clip or rope manufacturer's
recommendation, and shall be equal to or greater than the rope strength.
Hoisting ropes shall be the rated capacity load plus the load block weight
divided by the number of rope parts, and shall not exceed 20 percent of the
certified breaking strength of rope. Hoisting ropes shall be secured to
hoist drum so that no less than two wraps of rope remain at each anchorage
of hoist drum at the extreme low position (limit switch stop).
2.3.4
Sheaves
**************************************************************************
NOTE: Sheaves are used in the reaving similar to
pulleys and are not required on single reaved hoist.
**************************************************************************
Sheaves shall be of cast, forged, rolled, or welded structural steel.
Sheave grooves shall be accurately machined, smoothly finished and free of
surface defects.
2.3.5
Hoist Drums
Hoist drums shall be of welded rolled structural steel, cast steel, or
seamless steel pipe. Drums shall be machined and provided with right-hand
and left-hand grooves to take the full run of cable for the required lift
without overlapping, plus a minimum of two full wraps of cable when load is
on floor. At least one groove shall remain unused when hook is at the
highest position. Drum grooves shall be cut from solid stock and have
sufficient depth for size of cable required. Drum flanges shall be guarded
so that the cable cannot wedge between drum flange and hoist frame.
2.3.6
Gearing
Gearing shall be of the enclosed gear reducers type. Gears and pinions
shall be spur, helical, or herringbone type only, and shall be forged, cast
or rolled steel; open-type gearing is not acceptable. Gears and pinions
shall have adequate strength and durability for the crane service class and
shall be manufactured to AGMA 2001 Quality Class 6 or better precision per [
AGMA 2009-B] [AGMA 2011-A] [AGMA 2000].
2.3.6.1
Gear Reducers
Gear reducers shall be standard items of manufacturers regularly engaged in
the design and manufacture of gear reducers for Class D and G cranes or
SECTION 14630A
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