Figure 2-37.—Typical cable guides.
from rubbing against nearby metal parts. They are
Pressure Seals
also used as supports to reduce cable vibration in long
stretches (runs) of cable. Figure 2-37 shows some
typical cable guides.
Fairleads
Fairleads maybe made of a solid piece of material
to completely encircle cables when they pass through
holes in bulkheads or other metal parts. Fairleads
may be used to reduce cable whipping and vibration
in long runs of cable.
Split fairleads are made for
easy installation around single cables to protect them
from rubbing on the edges of holes.
Grommets
Grommets are made of rubber, and they are used
on small openings where single cables pass through
the walls of unpressurized compartments.
Pressure seals are used on cables or rods that must
move through pressurized bulkheads. They fit tightly
enough to prevent air pressure loss, but not so tightly
as to hinder movement of the unit.
Pulleys
Pulleys (or sheaves) are grooved wheels used to
change cable direction and to allow the cable to move
with a minimum of friction. Most pulleys used on
aircraft are made from layers of cloth impregnated
with phenolic resin and fused together under high
temperatures and pressures. Aircraft pulleys are
extremely strong and durable, and cause minimum
wear on the cable passing over them. Pulleys are
provided with grease-sealed bearings, and usually do
not require further lubrication.
However, pulley
bearings may be pressed out, cleaned, and
2-26
