Mechanical speed variator
PIV
The main reason why this variable speed drive was so successful is that it’s the only one to have a chain transmission. The device is made of:
Two pairs of opposed, grooved and keyed conical wheels on primary and secondary axis: one external control (manual or motorized) enables adjusting gap between wheels during their rotation. During the device’s assembling process, each wheel is set up in a certain way that ensures that it’s grooves are perfectly located in front of the opposed wheel’s teeth.
One chain with mobile strips that come and lodge in the wheel’s grooves thus eliminating any risk of sliding. The transmission is therefore positive. A special device constantly regulates the different games (including game from wearing) to always keep the chain tightened: it’s called the automatic retention.
A cast iron gearbox (non compulsory) perfectly sealed and oiltight which contains all the oil required for it’s proper and secured functioning
-
video
