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|  MIL-H-904J
speed of 15 ft/min and a maximum of 70 ft/min. All hoists shall be clean and free of foreign
material and excess lubricant. During operation of these hoists, no wear particles greater than
0.031 inch in any direction shall be generated.
4.7.8.2 Inspection after test. After completion of the tests specified in 4.7.8 and 4.7.8.1, gears,
chain, bearings, chain sprockets, brakes, and other wearing parts shall be examined for excessive
wear. Excessive wear is defined as that which impairs safe operation of the hoist. Reduction of
bar diameter of link chain in excess of 10 percent load brake lining reduced in excess of 50
percent of useful life, and life-lubricated bearings requiring lubrication is evidence of excessive
wear. Evidence of excessive wear shall be cause for rejection.
4.7.8.3 Additional testing. After completion of 4.7.8 and 4.7.8.1, tests specified in 4.7.1 and
4.7.2 shall be conducted to demonstrate hoist is still safe to operate.
4.7.9 High-impact shock. Hoists shall undergo the high-impact shock test in accordance with .
MIL-S-901 and as specified herein (see 6.3). Hoists shall undergo the grade A tests specified for
a principal unit. Resilient mountings shall not be used. Trolley hoists shall be secured only by
their own track clamps. Trolley hoists and hook suspension hoists shall be mounted in their normal
position. Type H hoists shall be tested in stowed position (horizontal attitude), constrained (not
fastened) to prevent lateral movement, and clamped or strapped to resist vertical movement and
prevent the test unit from hemming a missile hazard to test personnel. Hoists shall have load
hook or load block retracted for the test. The chain shall be looped in loops not to exceed 2 feet,
and secured in or lashed to the load hook during the test. The test fixture for mounting the hoist
shall conform, as applicable, to the deck-platform or bulkhead mounting figures shown in MIL-S-
901. The test fixture for mounting hoists differing from those specified shall require prior review
by the acquisition activity. Shock tests shall conform to the requirements as specified for the
lightweight or medium weight test. Separation of component parts of the hoist during the test,
evidence of permanent deformation of the hoist during inspection, or failure of the hoist to
conform to the requirements of 3.3.1 following completion of the shock test shall be cause for
rejection. Following successful completion of high-impact shock test, the hoist shall be subjected
to the following tests:
a.
Static and dynamic overload tests (see 4.7.1 and 4.7.2)
b.
Efficiency test (see 4.7.3)
c.
Plain and geared trolley test (see 4.7.5 and 4.7.6, as applicable)
d.
Track clamp test (see 4.7.4, as applicable).
4.8 Inspection of packaging. Sample packs, and the inspection of the preservation, packing,
and marking for shipment, stowage, and storage shall be in accordance with the requirements of
section 5 and the documents specified therein.
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