Fontaine’s 7000 Series fifth wheels have 55,000-lb vertical and 150,000-lb drawbar pull capacities. They feature the self-adjusting No-Slack II locking mechanism, a safety trigger and light release-handle pull force.
Any fifth wheel is an extremely important piece of equipment, since it is primarily a tractor-trailer coupling device. It has a locking mechanism, sometimes called jaws, which holds on to a kingpin that protrudes downward under the nose of a trailer. The lock can be released manually, by pulling a handle on the fifth wheel, or by air pressure applied through a valve inside the cab.
A fifth wheel must hold the tractor-trailer connection securely at all times, but it also must provide a pivot point, which allows a rig to make turns. Also, fifth wheels have a large, flat top plate, which spreads out loads and adds stability, and most top plates tilt fore and aft. This allows vertical articulation of the tractor-trailer, and eases coupling by letting the trailing edge of the plate slide under the leading edge of the trailer as the tractor is backing into position.
Fifth wheels are available in various load ratings and configurations for virtually any application. Here’s a rundown of the various types. For a full listing of specifications by manufacturer, visit www.ccjmagazine.com.
Types of fifth wheels
A sliding fifth wheel or ‘slider’ can be moved forward and rearward to affect axle weight distribution, overall vehicle length and ride quality. It’s mounted on a track that has locking pins to keep it in the desired position while the vehicle is moving.
A slider allows the use of different trailers with kingpins that are mounted closer to, or farther away from, the nose of the trailer. In addition, maneuverability can be improved in
ConMet’s Simplex 400’s compression locking system is designed to minimize high hitching and provide maximum kingpin bearing area. The cushioned system offers slack-free coupling by compensating for wear to the kingpin and jaw, and also aids in load dampening. When jaw adjustment is necessary, says ConMet, it can be accomplished in minutes.
