The TRIDEC steering system type HF is a hydraulic steering system used on trailers with a single swivel axle, possibly in combination with one or more rigid axles. The hydraulic system makes it possible to make a connection from front to back in cases where this is not possible mechanically, for example a tank trailer with a single steered axle. If additional manoeuvrability is required during shunting, the HS system can be fitted with a manual steering system. The driver then has the option of steering the trailer independently of the truck, using a remote control unit.

The system consists of a fifth wheel plate (which replaces the usual fifth wheel), a hydraulic unit and an axle unit mounted directly on the axle housing. These components are connected to one another by a closed hydraulic dual-circuit system. The HF fifth wheel plate has a king pin and a steering wedge that are automatically locked in the fifth wheel on the prime mover when the trailer is hitched. When the prime mover is turned, the turntable plate in the fifth wheel plate turns with it via the steering wedge thanks to the fixed connection. The steering rod transmits the steering motion to the 2 hydraulic cylinders situated in parallel via the bearing journal at the top of the turntable plate. The movement of the hydraulic oil is transmitted to two cylinders fastened on the axle unit via steel pipes and hoses. These cylinders transmit the steering motion to a transfer lever. Track rods then run from the transfer lever on the axle unit to the track rod arms on the swivel axle. The parallel motion of the cylinders is a construction patented by TRIDEC that ensures an equal displaced volume of oil and prevents any increase in pressure in the system. This keeps the vehicle stable and easy to control.

TRIDEC steering systems steer with the vehicle moving both forward and in reverse. So the vehicle remains optimally manoeuvrable at all times.

Maintenance is limited to lubricating the turntables a few times a year, visual inspection of the hydraulic components and testing the bolt connections. This is possible because high-quality materials and a durable construction are used. The steering rod bearings patented by TRIDEC, for instance, are entirely maintenance-free, thereby lengthening the trailer's service life. The turntables are sealed by a special seal. In addition, all lubricating points are centralised at a single, easily accessible point.

TRIDEC has an advanced engineering department which is responsible for the entire technical preparation and processing of your order. By means of specially developed software, a turning circle calculation can be made that simulates the road behaviour of your trailer when cornering. Interference checks and construction recommendations provide you with a customised system for your chassis. This gives you a system with the perfect combination between optimum steering and maximum reduction of friction.


Gümaş Otomotiv Sanayi ve Ticaret A.Ş.
Taksim Cad. No:33/A 34437,
Taksim - İstanbul

t: 0212 254 78 05
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