Continuous Variable Transmission (CVT) Mk 2
Built by Michelle O’Brien in July 2014
This is a Continuous Variable Transmission (CVT) test rig, employing two metal cones obtained for under a pound from the kitchenware section (top floor) of TK Maxx in Lewisham (traditional vintage Meccano doesn’t have cone shapes), some Araldite and a standard Meccano rubber driving band. And somewhat amazingly it works very well.
The input cone is powered by an electric motor. This cone turns at a constant speed and drives the second cone — the output cone — through a Meccano rubber band which can be made to slide up and down their length. The mechanism exploits the changing diameters of the cones that the driving band encounters as it slides.
I adapted the TK Maxx cones to Meccano use by putting a collar inside each of the narrow ends, a bush wheel inside each of the wide ends and pulleys of varying sizes spaced out inside along the length of the cones, everything held firmly in place with Araldite.
When I was building the mechanism I feared that the failure point was going to be the rubber driving band between the two cones slipping whenever the output shaft came under increased load. But to my surprise the transmission has prove to be remarkably positive. The driving band doesn’t slip even when you grab the output shaft with finger and thumb and squeeze hard.