REVIEW 2 QUESTIONS
What components of a track chain wear faster
than the other components?
What measuring device is used to measure track
What is the most common type of track shoe?
What component of the track frame serves as a
guiding support for the track chain?
What component of the track frame holds the
track in correct alignment with the driving
WINCHES AND WIRE ROPE
Learning Objective: Describe the operation of a
winch. Identify the characteristics and maintenance of
Using a winch and some type of rigging, a vehicle
can pull itself or another vehicle through such
obstacles as muddy or rough terrain. This is the
primary reason for providing winches on military
In the Naval Construction Force (NCF), an in-
depth management program for maintenance and use
of all rigging gear is required to ensure all operations
are performed safely and professionally. These
guidelines are outlined in the COMSECOND/
COMTHIRDNCBINST 11200.11, Use of Wire Rope
Slings and Rigging Hardware in the Naval Construc-
tion Force and the NAVFAC P-307, Management of
Weight Handling Equipment.
Most winches that you will encounter are used on
tactical vehicles and construction equipment. On
tactical equipment, the winch is mounted behind the
front bumper and is secured to the front cross member
of the frame or between the two side frame rails. In
some cases, it may be mounted behind the cab of the
vehicle. The typical front-mounted winch is a jaw-
clutch worm-gear type (fig. 6-31).
The jaw-clutch winch consists of a worm gear that
is keyed to a shaft. A bushed drum is mounted on the
worm-gear shaft, which is controlled by a hand-
operated sliding clutch. The worm shaft is driven by
power from the power takeoff through a solid drive
shaft and universal joints. The universal joint yoke,
connected to the worm shaft of the winch, has a
provision for a shear pin that is made of mild steel. This
pin has a predetermined breaking strength that allows
it to shear when the winch is overloaded.
A hand-operated sliding clutch is keyed to the
worm-gear shaft outside of the winch drum and must
be engaged with the jaws on the side of the winch drum
when the winch is to be operated. Disengagement of
the sliding clutch permits the drum to turn on the
Figure 6-31.Jaw-clutch worm-gear winch.