Mechanisms, Math and Groceries: the Computing Cheese Cutter

This paper is about a device that was popular in the US in the early 20th century, but is now just a curiosity item found in some antique stores: the computing cheese cutter. Computing cheese cutters were used in grocery stores to slice, with a remarkable degree of precision, cheese wheels by weight or by price. This work analyzes one kind of those devices, which allowed the shopkeeper to cut perfect slices by operating just two levers, which trigger the computation of the relationship between the weight of the whole cheese wheel and the weight/price of the slice to be cut. A brief overview of the several patents related to computing cheese cutters is then followed by a kinematic analysis which outlines the fascinating solutions behind the automatic weight/price calculation.