Fitting and component parts
Winning product advantages impress our customers:
The construction of JOST fifth wheel couplings guarantees the highest degree of safety.
The tappets in the insertion area ensure that the king pin is guided accurately into the fifth wheel coupling (2).
The recess on the patented lock jaw prevents dangerous false locking (3).
The locking bar, supported on both sides, guarantees an extremely stable safety system (4).
The adjusting screw allows the lock to be subsequently adjusted continuously, resulting in lower wear.
Wearing ring easy to replace without dismantling the fifth wheel coupling.
Wearing ring with plastic insert: for the JSK 37 E, JSK 37 EW, JSK 37 CW and JSK 42 series.
Steel wearing ring: for the JSK 37 C, JSK 36 DV, JSK 38 and JSK 50 series.
When choosing a fifth wheel coupling, you should especially take into consideration the requirements placed on bearing arrangements, mounting and maintenance. Basically, JOST fifth wheel couplings can be used universally.
Rubber bearing – Model “C”
Fifth wheel couplings with rubber mountings are particularly suitable for poor quality road surfaces. The rubber cushions are shock-absorbent and maintenance-free.
Pivot bearing – Model “D”, “E” and “K”
The pivot bearing allows for low mounting heights and is maintenance-free in the "E" and "K" version. They are especially well suited to use in sliding and dual-height fifth wheel systems. Model “K”: protects the chassis dues to its longitudinal elasticity (lateral movement).
Cardan mounting – Model “G”
The cardanic bearing is designed to allow roll between tractor and semi-trailer under off-road conditions. The lateral suspension can be disabled for on-road use.
The fifth wheel coupling is fixed to the tractor chassis by means of a mounting plate. Various mounting plate and fifth wheel mounting heights are available to make an accurate match between the height of the fifth wheel and existing trailer systems possible.
The fifth wheel coupling is built onto either the chassis or sub-frame of the tractor. The JOST mounting instructions for fifth wheel couplings and mounting plates, as well as the respective mounting instructions supplied by the vehicle manufacturer must be observed when mounting or converting equipment.
Always safely coupled: sensor solutions
A modern vehicle fleet places complex demands on operators and drivers. It is thus essential to make it as safe as possible to operate the vehicle, to keep down the standing time and to avoid accidents. JOST has therefore developed various systems that build on each other like stepping blocks to automate or support manual procedures; they thereby not only increase safety, but also efficiency.
All systems support the driver in the coupling process and/or in checking the fifth wheel coupling locking mechanism. This may be handled via an LED display on the coupling itself, driver assistance systems with remote display and/or remote operation in the driver‘s cab, or KKS, which automates the entire coupling process.
More information on the sensor solutions in the Systems chapter in this catalogue.
Everyone knows that regular, thorough maintenance is the most important factor in ensuring a long life span for a fifth wheel coupling. But lubrication causes downtimes, costs money and harms the environment. To improve the situation, there is a range of solutions that make lubrication easier or even entirely unnecessary for a period of time.
The series JSK 37 CW/EW fifth wheel couplings and all the series JSK 42 fifth wheel couplings in version “W” are equipped with a skid plate on the mounting surface and a wearing ring with plastic insert in the locking mechanism. In conjunction with the maintenance-free rubber or pivot bearing, only one greasing point on the lock jaw needs local lubrication. All wearing parts can be replaced quickly and easily. Low-maintenance fifth wheel couplings therefore save both time and money, as well as conserving resources.
„LubeTronic 1Point“ variant
Thanks to the top-plate liners, low-maintenance fifth-wheel couplings (Series W) do not have to be lubricated on the coupling plate, but rather only on the lock-jaw. The use of LubeTronic 1Point combined with a specially-coated lock jaw also eliminates this procedure. The LubeTronic 1Point must be replaced every three years.
„LubeTronic 5Point“ variant
LubeTronic 5Point was developed for fifth-wheel couplings without top plate liners. It is a lubrication system that is integrated into the fifth wheel coupling and ensures reliable lubrication of the fifth wheel coupling plate and lock jaw. (Design in accordance with Regulation R55-01, Attachment 7).
Fifth wheel couplings and mounting plates
Fifth wheel couplings are fitted to a tractor unit to connect it to the trailer.
Fifth wheel couplings are vehicle attaching parts that are subject to mandatory design approval and on which the highest safety requirements are placed. We can supply a suitable fifth wheel coupling for all applications, thus always guaranteeing a safe and secure link between the tractor and trailer.
When mounting, using, converting or exchanging our fifth wheel couplings, the vehicle manufacturer’s notes, JOST instructions for mounting and use, and the relevant national regulations must be observed. In Germany these are §§19, 20, 21, 27 of the “StVZO” Motor Vehicle Safety Standards.
The JSK 42 is available with a large selection of pedestals in all common heights and with all common hole patterns for plate and frame assembly. Depending on the model and height, it is possible to reduce the weight by 30 to 60 kg. This fifth-wheel coupling is also exceptionally easy to operate: the convenient handle enables you to release the lock and open the JSK 42 with one hand.
Design / features
JOST fifth wheel couplings fulfil the most stringent requirements in terms of safety, simple operation and ease of servicing. This results in the following benefits:
- High level of operating reliability
- Can be used in complicated loadingconditions
- Automatic latch arrangement
- Only a visual inspection is required toensure proper engagement
- Protection against unauthorised openingis possible using a padlock
Ease of servicing
- Infinite adjustment of the lockingmechanism, thus resulting in lower wear
- Wearing ring is easy to replace
- Easily replaceable top plate liners
- Wearing parts can be replaced withouthaving to remove the fifth wheel
- Long, easy-reach handle
- The operator does not get dirty
- The latch is released using a cable
- JSK 42: Single hand operation withoutlatch and cable
The fifth wheel type plate is secured on the side of the coupling plate. When ordering spare parts, please quote the model designation and the serial number.
Definition D value
The construction of the fifth wheel coupling in connection with the vehicle is carried out by the vehicle manufacturer (construction according to Directive 94/20/EC, Appendix VII).
The imposed load on the tractor and the D value are criterions for the load-bearing capacity of the fifth wheel couplings and mounting plates.
T = permissible total weight of the tractor unit in t (including U)
R = permissible total weight of the semi-trailer in t
U = permissible imposed load on tractor in t
g = 9,81m/sec2
The permissible load data for JOST fifth wheel couplings can be found on the type plate or from the JOST product catalogue. They apply for the intended use in compliance with the Directive 94 / 20 EC or ECE-R55.
If additional dynamic demands are to be placed on the coupling, e.g. by use on uneven road surfaces or building sites, the imposed load and D value should not be fully used or a stronger fifth wheel coupling should be fitted, and/or you should ask JOST for advice.
Fifth wheel couplings are fitted to a tractor unit to connect it to the trailer. Fifth wheel couplings are vehicle attaching parts that are subject to mandatory design approval and on which the highest safety requirements are placed. We can supply a suitable fifth wheel coupling for all applications, thus always guaranteeing a safe and secure link between the tractor and trailer. When mounting, using, converting or exchanging our fifth wheel couplings, the vehicle manufacturer’s notes, JOST instructions for mounting and use, and the relevant national regulations must be observed. In Germany these are §§19, 20, 21, 27 of the “StVZO” Motor Vehicle Safety Standards.
JOST mounting plates for fifth wheel couplings satisfy the requirements of Directive ECE R55-01 – Class J and are approved for the steering forces of steered semi-trailers. We also offer a selection of mounting kits for connecting mounting plates and fifth wheels to the tractor unit.
Explenatory notes for the following selection tables
WA / Maintenance
M = Manual lubrication
Z = Prepared for connection to the central lubrication system on the tractor unit
W = Low-maintenance, lubrication only required on the lock jaw
M, Z = Available either for manual lubrication or prepared for central lubrication
LT 1P = LubeTronic 1Point
LT 5P = LubeTronic 5Point central lubrication system
ZL / Handle length
J = Long handle
K = Short handle
ST = Standard
MAN = MAN
VT = Volvo Truck
MB = Mercedes-Benz
RT = Renault Truck
DAF = DAF
IV = Iveco
SC = Scania
DW = Daewoo
FO = Ford