Ball bearing turntables and slewing rings are parts for fitting onto trailers and agricultural vehicles to connect the A-frame to the trailer chassis so it can swivel.

Ball bearing turntables and slewing rings must always be operated as set out in the relevant operating instructions for the particular vehicle.
Compliance with ”TÜV” Safety Regulations and Motor Vehicle Safety Standards (StVZO) is required in Germany.

JOST ball bearing turntables and slewing rings cover the complete spectrum of trailer technology and have a solution to suit all applications.
Axial Load
The range of applications for ball bearing turntables and slewing rings depends on the maximum axle load. JOST ball bearing turntables and slewing rings cover an axle load range from 7.5 to 250 kN.

The specified axle loads for series KDL, HE, SO and ND relate to use where the slewing ring is mounted on the front axle of a trailer with three axles and fifth wheel steering, travelling at speeds of up to 100 kph (65 mph). On dual-axle trailers, the specified axle loads can be exceeded by 10% or 20% at speeds below 30 kph (18 mph).

All load data for series KDL, HE, SO, ND and N apply to use on roads in fifth wheel steering systems and for paved standard road conditions in Central Europe.

If the ball bearing turntable and slewing ring are to be mounted above the steered axle and above the king pin on semi-trailers, please ask JOST for the load data, giving details of the vehicle. Any deviations are given on the specification sheet.

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Design / Features
The ball bearing turntables and slewing rings allow the bogie to turn relative to the trailer frame. They transfer both the axial force and the thrust and tensile forces that occur during a journey.
The lower ring/outer ring is bolted on to the A-frame and the upper ring/inner ring is bolted to the chassis. The A-frame, ball bearing turntable or slewing ring and chassis must never be welded together. Pre-welded stop blocks relieve the shear load on the bolts resulting from horizontal forces.

The ring must be mounted on a completely flat and rigid base with at least 50 % of the circumference adequately supported.

Ball bearing turntables are available in drilled and undrilled versions.
Slewing rings are available in undrilled versions only.
JOST standard ball bearing turntables are supplied with a thin base coating of lubricant. Before it is used for the first time the ball bearing turntable must be lubricated thoroughly. See JOST installation and operating instructions.

Connection to the central vehicle lubrication system is possible (grease is essential, rather than oil).

The low-maintenance versions of ball bearing turntables and slewing rings mean they do not have to be maintained for up to three years or 300,000 km. After this period they must be serviced in the same way as standard turntables. The low-maintenance models are distinguished by a green type plate and by the letter “W” at the end of the item number. Maintenance conditions differ when fitted to steered semi-trailers or in the case of heavy conditions of use.

Technical Specifications
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