- said projections (10) are arranged so as to place the length of said flanges (2b) in a determined angular position with respect to the rows (6) of openings (7), and - the openings (7) of a first row (6) of openings (7) are arranged with respect to a second row (6) of openings (7) adjacent to said first row (6), such that after installation of the elongated objects on the tray (1), the flanges (2b) of the objects inserted in the openings (7) of said the first row (6) imbricates with the flanges (2b) of the objects inserted in the openings (7) of said second row (6), i.e. each flange (2b) of an object of said the first row (6) is positioned in a space existing between the two adjacent flanges (2b) of the objects of said second row (6), in the immediate vicinity of these two flanges (2b).
