General Information
The Aussie Locker is a fully automatic and precision manufactured automatic differential locking device that does not require any manual operation to activate. It does not require any switches, external compressors, electrical cables, air lines, or pneumatic controls. The Aussie Locker relies on a simple and highly innovative mechanical design which makes use of two distinct sets of forces, "ground driven" forces acting on a wheel when cornering (forces the outside of the wheel to turn faster) and the engine driven forces through the drivetrain. The combination of these two sets of opposing forces and the unique Aussie Locker design allow the automatic locking and unlocking of the driving gears when a vehicle turns or requires differential action.
How the Aussie Locker is different from a standard differential
A standard differential is designed to perform two main traction related operations; Transmit engine power via the drive line to the wheels, Allow “differential action”, i.e. allow the wheels to travel at different speeds to allow cornering without drive train damage or tire damage.The traditional differential design allows for an infinitely variable rate of differentiation ranging from 50:50 where both wheels turn at the same speed (straight line driving) and a ratio of 100:0 where one wheel spins freely and the other is not driven at all (not what you want to face when off roading). The traditional differential also allows for all power to be transmitted to the “path of least resistance” which is fine on highways because both wheels have some degree of traction but off road you often require substantial power and in this case even a small difference in traction can result in wheel spin and the subsequent loss of traction.
A limited slip (LSD) differential is simply a standard differential (also called open) with either a fixed bias or dynamic biasing mechanism which serves to only “partially” lock up” the two axles by way of clutch plates or special gear design. However, most require that both wheels still have some traction on the ground to operate and even when new will cause a wheel in the air to spin uncontrollably so as to be completely ineffective where off road traction is required. The Aussie Locker overcomes the traction deficiency of the standard differential and a limited slip differential so as to ensure that 50:50 power split is achieved when driving irrespective of ground conditions, yet still allowing differential action when required.
The Details
Simple explanation of the Aussie Locker operation
Unlike a standard differential, the engine can never drive one wheel faster than the other.The Aussie Locker mechanism allows a wheel to turn faster than the speed of the differential that is driving it (differentiation), but never allows a wheel to turn slower than the speed the differential and engine is turning it (traction). Therefore, a wheel cannot ever stop turning if the engine is driving it, but in a corner it can be forced to actually turn faster.
100% positive locking
Is positive locking, meaning there is no slippage when locked.There is a mechanically solid engagement of all parts. In contrast a limited slip differential is not positive locking and does allow slippage and one wheel "spin up" i.e. the spinning of one wheel at twice the differential speed while the other wheel having traction remains motionless. With the "Aussie Locker" you get 100% of drive and traction to both wheels at all times.
Dynamic Locking Principle
Has a locking and unlocking principal that is dynamic.Dynamic in that the more power that is applied, the harder it locks so it doesn't need large bias forces operating on it to keep it locked. The bias spring forces are minuscule and can easily be compressed with two fingers. This results in a locker that is able to lock and unlock easily even when driving on extremely slippery surfaces like mud and wet grass. The locking mechanism is so sensitive that a wheel can be disengaged with one finger when a wheel is jacked up, off the ground. The "Aussie Locker" engineering philosophy is based on two sets of opposing forces but simplified over other automatic locker designs. Basically there are two forces acting on the two gear sets. One acting to unlock the cam and axle gears by the gear tooth design and effects of the ground driven forces acting on a wheel when cornering. The other is acting to lock the cam and axle gears due to the camming action of the cross shaft and axle gear due to the 4 dimensional spiral cut cam grove with bearing surfaces under the effects of engine power Depending on the situation, the locker can either uncouple the driving gears i.e. if the differential force is acting on a wheel to turn it faster than the wheel is being driven by the differential and engine, then that side can freely disengage and unlock providing differential action.
Load transfer and strength
Uses a large number of very low profile teeth which collectively do all the ramping and the driving.Engine power is transferred through the flats of all 20 teeth at the same time rather than the original standard differential which has only 2 or 4 teeth driving at a time with all the force being transmitted between two points on the curved surface of the pinion and side gear teeth. The Aussie Locker Has 2-5 times greater surface area over which to transfer the engine power. This means that the Aussie Locker can handle engine power often found in modified off road vehicles with large tires. The design of the locker result in the gears being locked when driving vs. the slipping and sliding that occurs when traditional spider and side gears turn and mesh.
Constant 4WDs
Some vehicle owners install part-time kits or use free wheeling hubs.Like all automatic lockers, the Aussie Locker cannot be used in front axles of constant 4Wheel Drive vehicles. Some vehicle manufacturers offer a part-time 4WD option and automatic lockers can be installed.