Hi All
Here is a clip from LOkka
http://www.4wdsystems.com.au/index.php?id=29
I would argue their use of the term "unlocking" (point 3b below) as to me an unlocked wheel could be held stationary whilst the other is powered such as when we are talking an open diff or even limited slip. Yes it is not "locked" equal to the other wheel at all times but it cannot turn slower or not at all when power is being delivered to the diff. Both wheels have to at least turn the speed of the diff being driven by the prop shaft. So to me neither wheel is ever unlocked. Both wheels get equal power all the time AND are allowed to spin faster if in a turn. I think most of us are saying the same thing. I certainly don't like the term "unlocking" because if you were to go around a corner and be in some slippery stuff the outside wheel which by their terms unlocks could not stay stationary it will have power. Look at point 4 below. Like I said earlier the locker changes which wheel on bitumen when turning gets it's power as opposed to an open diff. This is why steering feels different after the locker has been installed. Maybe different models of lockers work differently and I'd be happy to see these because I want to install one myself fairly soon and want to have all the facts first. I'm open to anyone else wanting to post something different and links to where they get their information. The site I've listed above and clipped below supports all I've said so far for this particular model.
Cheers
Chris
Open Differentials and Limited Slip Differentials (LSD's) are designed to distribute enqine torque proportionately to the wheels, allowing the wheels to travel at different rotational speeds when cornering on hard road surfaces or travelling over very uneven ground.
When turning on a hard surface, "open" and LSD differentials use the outside wheel to drive the vehicle, while the inside wheel is allowed to "differentiate" or travel a shorter distance around the turn. The very nature of their design however is detrimental in relation to their ability to deliver equal torque to both wheels, hence traction and 4WD off road ability is severely handicapped.
LOKKA will perform the same as open and LSD differentials when the vehicle is driven under equal traction conditions, ie on road. The LOKKA allows the wheels to "differentiate" around the turn, but reverses the operation in that it transfers the engine torque (hence drive) to the inside wheel, rather than the outside wheel.
In comparison to other lockers LOKKA uses an amazingly simple method to .lock the axles for maximum traction and to unlock them for full differential action. ie as required when cornering or driving on hard surfaces.
The actual principal of it's operation while easily demonstrated is difficult to explain in writing - but is as follows.
1. LOKKA has only 4 main parts - a pair of Cam and Axle (side) gears for each axle, there are some springs and pins, some have spacers.
2. LOKKA is normally in a fully locked state and only allows differential action by unlocking the unit when the ground driven force acting on a wheel (either during turning or when negotiating obstacles) forces that wheel to turn faster than the other driven wheel.
ie a turning vehicle's wheels actually travel two different paths with the inside wheel turning in one circle while the outside wheel travels in a larger circle, and therefore faster.
3. LOKKA makes use of two distinctly different sets of opposing forces that exist due to its design - one to dynamically couple the gears when engine torque is applied and the other to uncouple the gears when one wheel overruns.
3a. The locking force is applied by the action of the pinion cross shaft acting on a uniquely designed and shaped cam - the more torque that is applied the harder the unit locks.
3b. The unlocking action occurs due to the ramping effect between the low profile ramped teeth which force the cam away from the axle (side gear) eg when an outside wheel turns faster than than an inside wheel when cornering. Power continues to be applied to the inside axle. As the turn is completed and the wheels again rotate at the same speed, the outside lock re-engages.
4. It should be understood that only when there is an external force being applied to a wheel to make it turn faster than the rest of the drive train will LOKKA allow one wheel to differentiate. Slippery surfaces where one wheel would normally break traction in an open diff cause LOKKA to stay locked - even with one or both wheels in the air, LOKKA will remain locked.