Since Fleet Owner last reported on fifth wheels, the biggest new development in the industry occurred last fall when Holland USA acquired the Simplex fifth wheel product line from Consolidated Metco.

The fifth wheel product line features the Simplex SE model, now called the Holland Simplex SE fifth wheel. The operating mechanism of this model has not changed, according to Holland. It still has just 12 components and five moving parts for simplicity and ease of maintenance.

Holland says that with only five moving parts, the eccentric adjustment pin and jaw can be replaced in 15 minutes, while the top plate remains on the tractor. This is an important characteristic for busy maintenance managers who need to streamline servicing procedures and get their fleet's tractor-trailers back on the road.

Other features of the Holland Simplex SE fifth wheel include a new eccentric pin design that allows for much finer increments of slack adjustment. The model also has new safety features, such as a new jaw return spring that's been added to prevent the jaw from closing while bobtailing.

The top plate of the SE fifth wheel has been retooled to maximize surface contact and extend product life. In addition, a Visual Safety Indicator has been added to provide the driver with a clear visual indication that the wheel is properly coupled.

Holland reports that in acquiring the Simplex line, it plans to build on ConMet's strong OEM and fleet relationships while leveraging its own common cast-steel know-how to provide improved fifth wheel products to customers.


Since safety is an ongoing concern of fleet managers, Jost International recently introduced a new coupling system that it says will, in time, change the procedure from today's manual approach to one that is completely automatic.

Jost notes that one of the factors facing the heavy-duty truck industry is limitation on growth due to driver shortages. Automating the trailer coupling procedure is one way the company can help fleets attract drivers and keep them safe on the job.

The new KKS automatic coupling system automates coupling and ensures that the various stages of hitching and unhitching can now be carried out and monitored electronically by remote control and in less time. This is a strenuous process that previously had to be done manually, Jost reports.

KKS installation is a two-part process: In the truck production center, the JSK 42 fifth wheel coupling is fitted with three sensors. One sensor gives information about the correct coupling height and automatically switches on the system when coupling. The second sensor checks the position of the kingpin, and the third checks the status of the lock. A pneumatic cylinder is also provided for the automatic actuation of the locking mechanism.

On the trailer, the kingpin is fitted with a wedge, which is supported on a rotating bearing. The interface provided at the fifth wheel coupling transmits the signals between the truck and trailer. The fifth wheel landing gear drive, which carries out the landing gear and cable drum operations automatically, is also installed here.

Completing the KKS system is the operator's module, which is installed in the driver's cab. The operator's module controls all hitching and unhitching processes, in conjunction with a central control unit mounted on the coupling, and displays the system status.

Fontaine International says that it's new 3000 Series fifth wheel, introduced last year, has become the standard fifth wheel on Volvo and Mack trucks. Designed for weight-conscious fleets, the 215-lb. 3000 Series fifth wheel is 10% lighter than Fontaine's C7000 model.

The manufacturer says the 3000 Series fifth wheels are engineered for durability and simplicity. There are only four moving parts, for example, contributing to low maintenance requirements. There is also infinite adjustment to control slack, and the fifth wheels have a wear ring for greater durability.

Safety is also built into the 3000 Series. Its locking mechanism, for example, features a patented kingpin height sensor that acts as a safety trigger. If the kingpin enters at the wrong height it will not allow the fifth wheel to close. Fontaine explains that this important safety feature eliminates false trailer coupling to prevent dangerous high-hitching.