Holland Fifth Wheels
General Information
Holland fifth wheels (Fig. 11.1) are bracket-mounted to
the tractor frame in a position that best distributes the
trailer load over the tractor axles.
The Type "B" kingpin lock mechanism (Fig. 11.2) uti-
lizes two spring-loaded lock halves. The final forward
motion of the kingpin into the open lock halves forces
the locks to close in a 360 degree grip around the
shoulder and neck of the kingpin, positioning sliding
yokes between the lock halves and tapered rib mem-
bers of the fifth wheel understructure. The kingpin can
be released only by manually operating the kingpin lock
control handle. The adjustment nut will compensate for
wear on the lock or kingpin.
The Holland Lockguard (Fig. 11.3) is a device that pre-
vents a false lockup, and is used with Type "B" kingpin
lock mechanisms. The Lockguard is a spring-tensioned,
smooth-surfaced tongue that the kingpin passes over
and depresses when entering the lock mechanism. The
Lockguard will prevent the locks from engaging before
the kingpin fully enters the locks. If the kingpin enters
the fifth wheel incorrectly and does not depress the
tongue, the locks are unable to close.
The Type "A" kingpin lock mechanism (Fig. 11.4) uti-
lizes a single hinged lock and cam arm. The final for-
ward motion of the kingpin into the open lock forces the
hinged lock to pivot on a pin and close around the king-
pin. The lock is held in place by a spring loaded
plunger. The kingpin can be released only by manually
operating the release handle. The adjustment nut will
compensate for wear on the lock or kingpin.
Fifth Wheel Locking Operation
Locking the Fifth Wheel Mechanism
1. Chock the front and rear of the trailer tires to pre-
vent the trailer from moving.
1
2
10/31/94
f310266a
1. Kingpin Lock Release Handle
2. Kingpin Lock Mechanism
Fig. 11.1, Holland Fifth Wheel
Fifth Wheels
11.1
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