Figure 38-6. Typical Three-Quarter Trailers.
is pivoted to a landing gear casting so that the wheel
are constructed with a simple type of fifth-wheel
may be raised or lowered. A removable pin can be
consisting of two large steel plates and a kingpin. In a
placed in various holes of the yoke to hold the wheel at
heavily loaded trailer, considerable binding between the
the desired height.
fifth-wheel plates hinders free steering, so when the
driver steers the motor vehicle to the right or left, the
binding fifth-wheel resists the turning effort and tends to
Section III.38-9.GeneralDescription. Full trailers,which
keep the motor vehicle traveling straight ahead. This is
support their entire load, may be connected directly
apparent to the driver when operating on slippery roads
behind the towing vehicle to a semitrailer or to another
and makes steering not only difficult, but dangerous. To
full trailer. They are independent and fully contained
overcome this, there is a tendency toward more refined
vehicles without motive power.
fifth-wheel designs that will turn freely under heavy loads
by the use of bearings.
Early full trailers were equipped with knuckle or
Ackerman steering used on motor vehicles, but all full
trailers now use fifth-wheel steering. Many full trailers