My mother-in-law had a stroke a while back and lost the use of her right hand and now has difficulty with basic things we all take for granted, like opening a fruit cup or a container of applesauce. I am in the middle of a Creative Engineering course and decided to do something about that. I had already designed a holder for her that kept the cups from sliding across the table while eating (with a pudding cup insert).
So I decided to work that original design into a device that would cut the top from the fruit cups instead of her fighting to peel back the plastic seal.
(Sorry for all the clear and transparent acrylic, but it was important for people to be able to see the inner workings.)
The holder gets inserted into the cutting base. The corner pads give some cushion if the lid is dropped shut and the center ones keep the cup from rotating when the plunger is turned.
Pushing down and turning the handle exposes the blades and cuts the top of the fruit cup.
And the whole thing can be operated with one hand.