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Page Title:
Test Method No. 2 - Lifting Speed - Lowering Speed - Lift Cylinder Cavitation Main and Auxiliary Hook Block Speeds |
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| MIL-C-53057(ME)
APPENDIX
TEST METHOD NO. 2
LIFTING SPEED - LOWERING SPEED - LIFT CYLINDER CAVITATION -
MAIN AND AUXILIARY HOOK BLOCK SPEEDS
1. TEST APPARATUS:
a. Linear measurement equipment.
b. Stopwatch.
c. Hydraulic pressure gages capable of reading below atmospheric
pressure.
2. TEST PROCEDURE:
a. Lifting and lowering speeds.
(1)
Record time in seconds required to raise the boom
utilizing only the boom lift cylinders from the
horizontal position (O degrees) to a boom angle of
60 degrees with the boom fully withdrawn.
(2)
Record time to lower the boom, utilizing only the
boom lift cylinders at maximum speed (full open
-
valve) from a boom angle of 60 degrees to 0
degrees with the boom fully withdrawn. Note
whether lowering speed remains constant throughout
the lowering operation.
(3)
Repeat steps (1) and (2) minimum of 3 times.
(4)
Compute lifting speed and lowering speed and use
the fastest rate obtained from each as the
established speeds.
(5)
Repeat steps (1) through (4) except hoist the hook
block (i.e., use the hoist mechanisms to lift the
hook block instead of tile lift cylinders) with
the boom at 60 degrees, fully withdrawn, and the
hook block travel distance from ground level to
maximum height. Record the travel distance.
(6)
Repeat step (5) using the auxiliary hoist system.
b. Lift cylinder cavitation.
(1)
Install the pressure gages to read hydraulic
pressure on both ends of the boom lift cylinder.
(2)
With the engine at low idle speed, and the boom
fully extended, raise the boom from horizontal to
maximum boom angle. Lower the boom to 0 degrees
and return again to maximum boom angle not less
than 10 times. Lowering shall be accomplished with
control valve open 5 times and "feathered" 5
times. Observe and record any evidence of
cavitation in the lift cylinder or loss of
operator control. Record pressure readings. Note:
Pressure readings are not required for determining
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