Product: Air Hoists
Models: All
Subject: Air Hoists
to meet MIL-H-28538A
By: Tom Gagnet, Engineer
No. UL-007
Date: 3/3/92
What does Ingersoll-Rand
need to do to meet MIL spec MIL-H-28538A?
When quoting hoist to meet MIL-H-28538A,
the following must be noted and/or exceptions taken.
This spec applies to air powered
wire rope or chain hoists of three sizes:
Size 2: 2 ton rating, 10-30
ft lift, 6-32 ft/min speed
Size 3: 3 ton rating, 10-30
ft lift, 6-17 ft/min speed
Size 5: 5 ton rating, 10-20
ft lift, 6-12 ft/min speed
Each hoist must be furnished
with plain trolley, air line filter an oil lubricator,
muffler, and a 40 ft air supply hose assembly. Any of
the above requirements may be modified by the order.
Ingersoll-Rand cannot quote
a special unit to fully meet all requirements, therefore
the following exceptions must be taken:
| 3.6.2
|
A mechanical
load brake and motor brake is required. Ingersoll-Rand
mechanical load brakes (wire rope hoists) can
not be lowered without power as required in 3.6.3.
This section is overlooked by some or some may
state that the mechanical brake may be released
by backing off an adjustment. This statement is
suspect as a self-energized mechanical brake under
rated load may not allow release by adjustment
due to internal forces. If a chain hoist is quoted,
this entire section must be taken exception to
as a mechanical self-energizing load brake is
not available from Ingersoll-Rand. |
| 4.
|
Bearings
may not have AFBMA numbers stamped on them. |
| 3.6.6
|
The wire rope is not
fitted with speltered sockets on both ends. Ingersoll-Rand
currently designs hoists to have two safety wraps
of rope on the rope drum at the lowest point of
lift. The rope ends at the drum are secured by
set screws, the dead anchor end by either speltered
sockets or standard thimble and clamps. This design
has been an Ingersoll-Rand standard since the
late 1950's. |
Note: If a first article
test is specified, it must be quoted by Marketing and
Engineering. Preservations and packaging should be specified
on the order as level A or C. If level A is specified,
it must be quoted by Marketing and Engineering. Level
C is in accordance with suppliers' standard practice and
does not require special quotation.
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