Abstract: An accessory for making patties from a vacuum filling machine uses a back and fro bidirectional sliding motion which alternately presents two or more openings to an output from a vacuum filling machine. In its simplest form, as a first opening is filled and a patty is shaped, simultaneously, in a second opening, a previously made patty is pushed out and the second opening thus liberated is slid back underneath the output from the vacuum filling machine to be filled while at the same time the first opening is emptied and then slid back underneath the output of the cacuum filling machine and so on. This unique simultaneous filling and emptying produces twice the yield that could be expected from a machine of a similar size.