Description - Main Applications - Frequently Asked Questions



Frequently Asked Questions

    - Why to you use your specific double rack to transform the linear movement into a circular one, and not another system?
    - Will freewheels or directional clutches support high torque and frequency?
    - Are the racks are not likely to tilt laterally under the effect of the pressure between a rack and two gears, which creates a torque of torsion?
    - Will the spring that transmit the torque not go through a too high constraint?
    - Don't you think it will generate acyclisms?
    - What are the advantages compared to CVT using driving belts?
    - Are you going to grant licenses?


Why to you use your specific double rack to transform the linear movement into a circular one, and not another system?

This device is converting any linear motion (back AND forth) into the SAME one way rotation! One gear wheel us used when the rack moves to the left and the other when it moves to the right, as each one is equipped with a one way clutch.

The advantage is that it is possible to stop and reverse the direction of the rack's movement without changing the direction of rotation of the rear wheel.

That's why modifying the position of the slider on the oscillating lever has the effect to change the length of the rack back and forth movement during a cycle, and consequently the transmission ratio.


Will freewheels or directional clutches support high torque and frequency?

Such devices are commonly used in aeronautics and in automobile gearboxes. The best companies selling these products indicate for each the maximum transmittable torque.

However, care must be taken not to cause too many jerks when the clutch is engaged. In our transmissions, the linear speed of the rack is almost the same as that of the pinion with which it co-operates as it begins to drive the output shaft. This means that there is no shock when the rack starts transmitting torque..

With one rack, the speed of the rack is sinusoidal because it is moved by a crank/rod mechanism. The speed or the output gear is stable because it is linked to a freewheel. Therefore, the curbs representing their respective speeds during a cycle are quite different.

If the rack is moved by a cranck comprising a spring which is compressed when the resistive torque increases, the speed of the rack is limited when it would run faster than the output gear.

In this case also, the speed of the rack and the one of the output crank are equal when the rack starts transmitting torque to the output gear, and there is no shock when the rack starts transmitting torque by the freewhel.

It remains absolutely the same when the transmission ratio is lower.


Are the racks are not likely to tilt laterally under the effect of the pressure between a rack and two gears, which creates a torque of torsion?

This is indeed the case, checked with the models already made. The drawings are deliberately simplified, and it is clear that it takes three simultaneous supports: the two gears, each receiving a force in the opposite direction, and a bearing that receives a force in the same direction as one of the two sprockets.


Will the spring that transmit the torque not go through a too high constraint?

They do not transmit the torque itself, but a small part of it. It all depends on the designed trajectory of the crankpin.

If it were radial, the spring would have no constraint but the sensitivity to the resistive torque would be null.

With a trajectory having a very small angle with a radius, the effort experienced by the spring is very small (the torque multiplied by the sinus of the small angle). This angle can be set by the designer to a value that is sufficient to adapt the distance between the rotation axis of the primary shaft and the crank pin according to the resistant torque.


Don't you think it will generate acyclisms?

With more racks, it is only the fastest rack that transmits the torque to the output gear.

The curb of the fastest rack's speed is more stable than with only one rack.

It is an advantage to move the racks by a cranck comprising a spring, because at a certain elasticity of the spring, the curb of the fastest rack's speed becomes absolutely flat.

In this case also, the situation remains absolutely the same when the transmission ratio is lower.


What are the advantages compared to CVT using belts?

Rubber belt CVTs that are commonly used in small motorized vehicles provide an extremely poor mechanical efficiency, sometimes aroune 70%. Our tranmissions should be much more efficient because there is no slipping and no friction. It is purely gears.

They should also be easier to maintain and last longer, and their manufacturing cost is going to be much lower.


Are you going to grant licenses?

We had a private search report done by one of the best patent attorney firms in France, and we are now quite sure that the patents will be delivered easily in all countries where we will decide to apply for them. The PCT will be filed before March 11 2019, which is the first aniversary of the first French application.

We have already started licensing. One of our sister companies will manufacture bike transmissions under license, and we shall grant licenses worldwide to number of companies enjoying a good reputation.

We might also sell all the patents to a large group who will take care of licensing.

Do not hesitate to contact us.


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