Mk.2 Talus MB-4H
The Talus MB-4H tractor was designed in the early 1990’s and was required to haul the A75 lifeboat and carriage, weighing approximately 3 tonnes. In 2005 the A85 carriage and boat were gradually introduced into service, followed by an A85 Angled carriage that has a laden weight of 6.5 tonnes. Not surprisingly the tractor started to struggle with the increased payload, and a Mk2 version was designed using the following requirements and constraints:
- Output 50% more torque
- Maximum speed unchanged
- No change to the engine
- Joystick steering in addition to the existing twin hydrostatic steering wheels
- No significant change to the vehicle structure.
To achieve this requirement the following changes were instigated:
- The drive system was completely re-worked with fixed axles being replaced with wheel motors, and a fluid diff lock valve was replaced with the Poclain “Twin-Lock” system.
- The engine speed control was previously by Bowden cable and is now “fly-by-wire”. The mechanical control system on the existing diesel engine is operated by an electrical actuator.
- The operator instrumentation and controls have been completely revised to provide a more ergonomic solution.
- An HMI has been incorporated to provide a detailed level of on-board diagnostics.
In conditions where traction is poor the Mk2 machine has far superior performance to the original tractor, as the maximum torque can be developed at a much lower speed.