freightliner Columbia Driver Manual page 143

07/25/95
1. Locking Wedge
2. Slide Release Pull Handle
Fig. 10.15, Manual Release Sliding Fifth Wheel Mount,
MWS Model
Fifth Wheel Lock Mechanism for Trailer
Kingpin
The Fontaine fifth wheel lock mechanism for the
trailer kingpin (Fig. 10.16) consists of a spring-loaded
jaw and a sliding wedge.
The jaw and wedge each have a pin permanently
attached. The pin on the jaw and the pin on the
wedge fit into elongated notches in the lock control
handle. The notches in the handle control the limit of
movement for both the jaw and wedge. The notches
are arranged so that the wedge is actuated first dur-
ing release of the kingpin.
During lockup, the jaw is moved first with the spring-
loaded wedge being allowed to slip in place against
the jaw. A timing bracket ensures that the wedge and
jaw are moved at the proper time.
Placing the lock control handle in the unlocked posi-
tion moves the wedge away from the jaw. This action
unlocks the jaw so that it can be moved by the trailer
kingpin. When the tractor is moved out from under
the trailer, the kingpin moves the jaw until the kingpin
is out of the mechanism. With the jaw in the un-
locked position, the lock control handle will remain in
the unlocked position until manually moved by the
operator.
Fifth Wheels and Trailer Couplings
1
2
f310190
1
3
B
10/26/2010
A. Unlocked Position
B. Locking
1. Wedge
2. Jaw
Fig. 10.16, Fontaine Kingpin Lock Mechanism
During coupling (Fig. 10.16), the motion of the king-
pin entering the jaw will actuate the jaw and wedge.
The jaw will move behind the kingpin, followed by the
wedge. The purpose of the wedge is to reinforce the
jaw and take up slack around the pin. Any wear on
the jaw is immediately taken up by the wedge so
there is no slack in the connection.
Fifth Wheel Locking Operation
Locking the Fifth Wheel Lock Mechanism
CAUTION
Before attempting to lock or unlock the fifth
wheel lock mechanism of a sliding type fifth
wheel, the slide release pull handle, if so
equipped, and the slide locking wedges must be
in the locked position. This prevents the sliding
member from moving rapidly to the far forward or
rearward position, which could damage the fifth
wheel member or kingpin.
1. Chock the front and rear of the trailer tires to
prevent the trailer from moving.
A
2
C
f310184c
C. Locked
3. Trailer Kingpin
10.12