BRIEF DESCRIPTION OF THE DRAWINGS
The characteristic features of the invention are pointed out in the following description of some preferred but not exclusive embodiments, with reference to the enclosed figures, in which:
FIGS. 1, 2, 3, 4, 5, 6 are schematic, front views of the apparatus proposed by the invention, in as many successive work steps, being a part of a cycle;
FIGS. 1A, 2A, 3A, 4A, 5A, 6A are perspective views in different scale, of the above apparatus in the work steps mentioned above;
FIGS. 4B, 4C are top views of the apparatus in working configuration of FIGS. 4, 4A, in one case with the flat folded blank, and in the other case with the blank squared by external means.