An element (1) configured to, in an active state, be arranged in a corner (40) of a parallelepipedic cage-like structure,
- said cage-like structure having top and bottom planes (42, 41) and walls (14, 15) extending perpendicularly between said top and bottom planes (42, 41),
- said corner (40) of said cage-like structure located where the bottom (41) or top (42) plane of the cage-like structure meets said walls (14, 15) of the cage-like structure,
- the element (1) comprising
- a bottom portion (2) having a flat surface (3) configured to bear on a thin side (4) of two first board-like members (5) of the cage-like structure meeting each other at the corner (4) of the cage-like structure and each said first board-like member (5) of the cage-like structure extending from the corner (40) of the cage-like structure along said plane (41, 42) of the cage-like structure to a respective adjacent corner (40) of the cage-like structure,
- two outer wall portions (6, 7) configured to be located externally of the cage-like structure in said active state of the element (1) and extending from the bottom portion (2) perpendicularly thereto to each form a lateral support to a wide side (8) of a respective first board-like member (5) received in the element (1) in said active state,
- two inner wall portions (9, 10) located opposite to the outer wall portions (6, 7) and extending from the bottom portion (2) mainly in the same direction as the outer wall portions (6, 7), each with a distance separating the outer (6, 7) and inner (9, 10) wall portions to receive in said active state, said first board-like member (5) and a second board-like member (11) of said cage-like structure therebetween, with wide sides (8, 12) of said first and second board-like members (5, 11) bearing on each other in said active state, and each said second board-like member (11) of the cage-like structure extending along an edge (13) between two adjacent walls (14, 15) of the cage-like structure from one of said planes (41, 42) of said cage-like structure to the other, and
- two wall members (16, 17) extending from the bottom portion (2) perpendicularly to the outer (6, 7) and inner (9, 10) wall portions to define an opening (18, 19) into a space (20) of the element (1) defined by the wall portions (6, 7, 9, 10) and said wall members (16, 17), such that an extension of said first board-like member (5) of said cage-like structure is received in said space (20) in said active state, and with a width of said opening (18, 19) substantially corresponding to thickness of a thin side (4) of said first board-like member (5) of the cage-like structure, to form a support for and prevent the second board-like member (11) from leaving said space (20) in the direction of said opening (18, 19) along said plane (41, 42) of the cage-like structure in said active state,
- wherein the inner wall portions (9, 10) of said element (1) each comprises a spring member (90, 100) configured to, in a rest state, extend into said space (20) at least partly towards the opposite outer wall portion (6, 7) and to be urged away from this outer wall portion (6, 7) by said first and second board-like members (5, 11) when received between said wall portions (6, 7, 9, 10) in said active state, while storing potential energy and bearing onto and urging said second board-like member (11) of said cage-like structure to press said first board-like member (5) of said cage-like structure against said outer wall portion (6, 7) in said active state, and
- each spring member (90, 100) has locking means comprising a flap (91, 101) bent out from a main body (92, 102) of the spring member (90, 100) and protruding downwardly towards the bottom portion (2) of the element (1),
- said flap (91, 101) configured to, in the active state of the element (1), bear onto and urge said second board-like member (11) of the cage-like structure in a direction at least partly downwardly towards the bottom portion (2) of the element (1), to counteract movement of said respective second board-like member (11) away from the bottom portion (2) and out of said space (20) of said element (1).