Device for the manufacturing a block comprising a locking key and a folded shell that is scored and/or pre-grooved. The device includes a first device that includes at least one shaping device comprising a funnel having corner folding elements and at least a pressing element or a traction element. The at least one shaping device is configured to shape a sheet element into the folded shell so that corner edges of the sheet element are folded inwardly by the corner folding elements and sides of the sheet element assume a vertical position after the pressing or traction element applies a force to a center of the sheet element. A second device is utilized that includes at least a pressing element configured to insert the locking key into said folded shell so as to form said block.