This is Barbro's reply to Dr. Harris!
"I've never seen a three parallel bladed knife but
I find there are several patents about them e.g.
The latter patent includes the following paragraph:"
'The knife, according to the invention, comprises a
handle which is joined with multiple parallel blades
so that the number of cutting operations for slicing
a food product is reduced as every cutting operation
gives several slices at the same time. In a preferred
embodiment the invention relates to a multiple-blade
knife for cutting food products into slices, wherein
the multiple blades are arranged in parallel and joined
to a handle, and wherein the handle has means for
setting and adjusting the distance between the blades
and wherein there are means for a temporary removal
of the parallel blades in order to free the knife blades
from the food product after the cutting'.