Abstract: The invention relates to a table, shelving unit or modular structure comprising hollow sections with a square cross-section, which are mounted by means of coupling with safety retainers. The invention consists of upper longitudinal members (1) and intermediate longitudinal members (7) comprising hollow sections with a square cross-section, which are coupled to vertical structural elements (12) by means of longitudinal and transverse grooves, said assembly being secured with safety retainers (11).

Abstract: A tubular or hollow structure made from steel, aluminium or other materials using self coupling elements that is made up of at least two pairs of components and making the ends and sides whose ends are cut with a mitre or bevel, which have slots at points close to the ends into which slots are introduced that are made in parts positioned vertically to the legs, fitted with tips made from an elastomeric material located at the lower end of the stated components.