Figure 3-33.--Types of cable terminal fittings.
in the center of a cable run. Figure 3-33 shows the
Figure 3-34.--Thimble, bushing, and shackle fittings.
various types of terminal fittings.
Thimble, bushing, and shackle fittings may be used
essential that all turnbuckle terminals be screwed into
in place of some types of terminal fittings when
the barrel at least until not more than three threads are
facilities and supplies are limited and immediate
exposed. On initial installation, the turnbuckle
replacement of the cable is necessary. Figure 3-34
terminals should not be screwed inside the turnbuckle
shows these fittings.
barrel more than four threads. Figure 3-36 shows
turnbuckle thread tolerances.
After a turnbuckle is properly adjusted, it must be
A turnbuckle is a mechanical screw device that
safetied. There are several methods of safetying
consists of two threaded terminals and a threaded
turnbuckles. However, only two methods have been
barrel. Figure 3-35 shows a typical turnbuckle
adopted as standard procedures by the services: the
assembly. Turnbuckles are fitted in the cable assembly
clip-locking (preferred) method and the wire-wrapping
for the purpose of making minor adjustments in cable
length and for adjusting cable tension. One of the
terminals has right-hand threads and the other has
Adjustable Connector Links
left-hand threads. The barrel has matching right- and
left-hand threads internally. The end of the barrel, with
An adjustable connector link consists of two or
left-hand threads inside, can usually be identified by
three metal strips with holes so arranged that they may
either a groove or knurl around the end of the barrel.
be matched and secured with a clevis bolt to adjust the
Barrels and terminals are available in both long and
length of the connector. They are installed in cable
assemblies for the purpose of making major
adjustments in cable length and to compensate for cable
When you install a turnbuckle in a control system,
stretch. Adjustable connector links are usually used in
it is necessary to screw both of the terminals an equal
very long cable assemblies.
number of turns into the turnbuckle barrel. It is also
Figure 3-35.--Typical turnbuckle assembly.