Lightweight seat for high-density configuration and cluster of adjacent seat for high-density configurations

Cluster of adjacent seats for high-density configurations wherein a single support structure supports all the adjacent seats of the cluster, each seat comprising

• a support structure supporting a seat pan and a backrest;
• wherein
• the seat pan comprises a rigid shell, a lining and an intermediate foam between the rigid shell and the lining;
• the seat pan having an average vertical thickness equal to or less than 25 mm, or equal to or less than 15 mm, in at least most of the surface of a rear portion of the seat pan, defined on at least one rear third of the seat pan in a horizontal direction, and/or in at least left and right rear corner regions contained within a radius of at least 10 cm from the left and right rear corners of the seat pan;
• a front portion of the seat pan, covering at least a front third, or at least a front half, of the seat pan in the horizontal direction, is a collapsible portion of the seat pan, adapted to be collapsable under the weight of a user of the seat, the collapsible portion being formed by the portion of the rigid shell contained in the front portion of the seat pan, forming a descending slope with an angle of at least 15° regards the horizontal towards a front edge of the seat pan, and by the portion of the intermediate foam contained in the front portion of the seat pan, defining a wedge of at least 15°, filling the increasing distance between the lining and the descending slope of the portion of the rigid shell contained in the front portion of the seat pan.