MIL-J-26149E
4.6.2 Initial Inspection. The jack shall be disassembled to the maximum practical extent and completely Inspected. Each component shall be checked for drawing conformance as to dimensions, finishes, et cetera and this data shall be recorded. This data then becomes the reference data to be compared with the data obtained in 4.6.9.
4.6.3 Operational test. The jack shall be operated under the following conditions to insure that the performance of the various components comply with the requirements specified herein,
4.6.3.1 Pressure and leakage test. The cylinder and ram assembly of the assembled jack shall be tested by applying hydraulic pressure equal to 150% of the pressure at rated capacity. This test shall be performed with an appropriate load on the ram assembly to preclude damage to the ram stops. Any external leakage of hydraulic fluid exceeding 0.05 cc per hour shall be cause for rejection. The internal leakage of the pump shall not exceed 5.0 cc per hour, any excess of this quantity shall be cause for rejection.
4.6.3.2 Setting test with the jack in the fully extended position and supporting a fully rated capacity load, the ram safety device as applicable placed in nonoperating position or removed, the jack shall be allowed to stand for 1 hour. The height shall be measured at the beginning and at the end of this period. The rate of settling of the jack shall not exceed 0.020 inch (0.51 mm) per ram stage per hour under rated capacity load and excess settling distance shall be cause for rejection.
4.6.3.3 Bypass valve test. Each pump shall be tested by either sealing the outlet of the pump or by applying an external vertical load and operating the pump until the bypass valve opens. The bypass valve shall be adjusted as specified in 3.8.2.
4.6.3.4 Safety device test. The safety device shall be tested with the jack ram at the fully extended position and supporting a rated capacity load. The hydraulic system shall be Instantaneously vented to simulate a hydraulic failure. The safety device shall support the load. Failure to support the" load shall be cause for rejection.
* 4.6.3.5 Air Vent Assembly Test. The air vent assembly shall be tested to verify that when normally shut it will open automatically at an air pressure
of 100 ±- 10 psig.
4.6.4 Static-proof test. If the jack is provided with a screw extension, the jack shall be tested with the screw extension in the fully extended position by raising a vertical load equivalent to 150 percent of the rated capacity to the fully extended position. While in the fully extended
position, the vertical load shall be reduced to the rated capacity and maintained while the application of a horizontal load of 15 percent of the rated capacity is applied to the top of the extended screw extension. To complete the cycle, the horizontal and vertical load shall be removed and the jack ram allowed to return to the original position with not more than 50 pounds force (222 N) applied to the top of the ram. In case the jack should not be provided with a screw extension, the same loading procedure shall
apply. Failure of any part of the jack as a result of this test shall be cause for rejection.
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