1. Cap
9. Piston
2. Roller boss cap
10. Seal, piston
3. Roller, the cap
11. Pin, dowel, valve
4. seal cap
12. Valve stop
5. seal cap
13. Valve slide
6. Stud
14. Seal, cylinder
7. Seal, stud and piston
15. Cylinder
8. Seal, stud
Figure 12-57.—Liquid spring shock assembly.
on the slight compressibility of liquids. Figure 12-57
illustrates the disassembled spring assembly. Most of
the internal parts are classified as nonrepairable, and
damage will require replacement of the parts at the depot
level of maintenance.
The spring assembly contains 19 cubic centimeters
of oil, MIL-S-21568. The oil is confined within the
piston cylinder assembly, and any side movement of the
arresting hook shank must be against the compressibility
of the oil. The maximum travel or compressibility of the
overall liquid spring assembly is 0.68 inch. The
operating pressure within the assembly, when bottomed
out, will be as high as 20,000 psi. In the static condition,
the oil trapped within the spring assembly is under a
return preload pressure of 350 pounds, which is created
by the reassembly of the close tolerance parts that
confine the liquid.
the
The tolerances of parts within the liquid spring and
necessity to subject certain parts to approximately
–110°F for varying lengths of time during the
disassembly and assembly process make it impractical
for it to be overhauled at the lower levels of mainte-
nance.
DAMPER CYLINDER.—The representative
arresting gear assembly employs a vertical damper
cylinder and two horizontal dampers to dampen hook
motion caused by deck impact forces. See figure 12-58.
Two centering spring assemblies maintain the hook in
the center position.
With the arresting hook lowered, the centering
springs are adjusted in the following manner:
1. Center the hook assembly.
12-66
