Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras

Split Fifth Wheel Coupling

Technology Category/Market

Machine Manufacturing and Mechanical Engineering

Applications: To connect the tractor and trailer of an articulated semitrailer and load bearing, Automobiles, Vehicles Designing.

Market: The global automotive fifth wheel coupling market is projected to record a CAGR of 5.8% from 2023 to 2033. The market is valued at US$ 637.1M as of 2023, and by 2033, the market might reach a valuation of US$ 1.1B.

Targeted Industries

Watermarking IP design,

Electronic circuits

Image Gallery

Problem Statement

  • The tractor-semitrailer combinations are  becoming larger and longer, face the problem of off  tracking, which is the ensuing difference in path  radii between the front & rear axles as it  manoeuvres a turn.
  • Despite steering the rear axle of the semitrailer, a  way of mitigating off-tracking is to shift the fifth  wheel coupling rearwards. But, it is limited by the  distribution of the semitrailer’s load; any rearward  shift of the fifth wheel coupling results in reduction of  the total static load on prime mover’s front axle  and available traction, leading to directional  instability of the vehicle.

The aforesaid issues are eased with a mechanism to  reduce off tracking without affecting the load  distribution among the axles of the tractor.


The Present Patent discloses a fifth wheel coupling mechanism for coupling a prime mover and a semitrailer comprising of a roller mechanism and a cylindrical joint. The method for above mentioned subject matter comprising:

  • A roller mechanism and a cylindrical joint on either side of the rear axle of the prime mover.
  • Roller mechanism comprising plurality of rollers rotatable around their axis, fixed to chassis of prime mover, a track fixed beneath chassis of semitrailer, where rollers roll on track disposed above while articulating.
  • The cylindrical joint comprises of a kingpin, a cylindrical mating part adapted to engageably receive the kingpin, guide plate to guide the kingpin, a locking mechanism to lock kingpin in position.

Key Features/Value Proposition

Technical Prospective:

  • A hitch mechanism to join a tractor and a semitrailer consist of the cylindrical joint that offers reaction forces in the x-y plane of the vehicle and  most of the vertical forces are taken care of by the  roller mechanism.
  • The roller mechanism is to enable load transfer even when the vehicle is articulating.
  • The weight of semitrailer is distributed between its axle and the roller mechanism according to their respective distances from semitrailer’s center of gravity (CG).

User Prospective:

  • It does not involve any hydraulic/pneumatic circuits, nor Complex control circuits. It is of simple mechanism and requires minimal maintenance effort.
  • No additional drives or actuators are needed and hence it is economic. Also, no extra power is required, hence running cost is negligible.
Questions about this Technology?

Contact for Licensing

Research Lab

Prof. Sujatha C

Department of Mechanical Engineering

Intellectual Property

  • IITM IDF Number: 1481
  • IP Patent Number: 418981 (Granted)

Technology Readiness Level


Proof of Concept


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