 |
|||
|
|
|||
| ||||||||||
|
|  MIL-C-53057(ME)
accordance with SAE J1165 after completion of assembly of the crane
when tested as specified in 4.6.2.17.3.
3.12.9 External leakage. After completing tests specified in 4.6.2
the degree of external hydraulic system leakage shall not exceed a
class 4, for dust-free conditions and a class 4D for dusty conditions
of SAi Jl176. External hydraulic system leakage shall not exceed a
class 3 for production cranes under normal operation.
3.13 Superstructure. The revolving superstructure assembly shall be
capable of continuous 360-degree operation. The superstructure shall
be capable of a swing speed of not less than 1.75 rpm and not more
than 3.5 rpm at governed engine speed with the swing control on the
full open position and shall be equipped with a swing brake and lock.
The counterweight shall be made of a homogeneous material.
13.13.1 Pedestal. The pedestal and base shall be mounted on the
chassis to insure continuous 360 degree working range and shall
-
withstand the forces caused by lifting, swinging with rated loads,
and traveling without loads.
3.13.2 Boom assembly. The boom shall be of the hydraulically
operated telescoping type, consisting of the base section and one or
more sliding sections to reach the operating radii specified in
3.9.9. Extension and retraction of the boom sections shall be
accomplished by one or more hydraulic cylinders. If cables or chains
are used in the boom assembly, data shall be provided by the
contractor illustrating the capability of the cables and chains to
withstand a force of 3.5 times the total force in the cable chain
system when extending the boom at maximum lift angle carrying rated
load. The crane shall incorporate means to prevent accident or damage
from two-blocking. The prevention of two blocking shall be
-
accomplished by de-energizing the boom extension and load hoisting
functions. The boom lift shall have combination controls for hand and
foot operation.
3.13.3 Hook block. The crane shall be provided with a main and an
auxiliary hook block. The hook blocks shall be of the lubricated type
with swivel hook and safety latch. The main hook block shall be rated
not less than 40 tons and the auxiliary hook block shall be rated not
less than 8 tons. Both hook blocks shall be provided with a bucket
for ending the hoist cable at the hook block. The sheave shall
conform to SAE J881. All sheaves carrying hoist lines shall be
guarded to prevent the rope from leaving the sheave groove during
operation. The hook blocks shall have adequate weight to insure
payout of the wire rope without load on the hook when the boom and
hook block are in any position. The contractor shall provide
certification of the hook blocks' capacities at the time of first
article test.
3.13.4 Winch. The crane shall be provided with a hydraulically
driven main hoist drum and an auxiliary hoist drum. The assemblies
shall include a self-locking mechanism or self-energizing brake
capable of holding their respective maximum rated loads. The drums
23
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals