Aaaaaaaaaaggggggghhhhhh!

My initial idea is nearly what I have made. I wanted to use more engineering methods but could not work out the mechanism from the Camm to the cup rotation.
Cord and Pullies was my solution.

It’s intended that this will be powered by a motor and so using my cordless drill I realised that the main shaft is not equal and so shacks at a certain speed.

Using the hand lever I can be using it and have seen improvements needed.

The hand lever needs to rotate a grater ratio turn and so I can look at using cogs.

The section that holds the scissors needs to be anchored in a down position when rotating the hand lever. Easily fixed with cord or a clamping mechanism.

With two pairs of scissors I can always fit a third.

The rotation plate that turns the cup needs something applied to hold the cup.

All in all very pleased.