A grid framework structure

A grid framework structure for supporting a load handling device operative to move one or more containers, said grid framework structure comprising:

• A) a track system for a first and second type of robotic load handling device to move one or more storage containers, the first type of robotic load handling device having a different sized footprint to the second type of robotic load handling device, the track system including;
• i) a first portion including a first set of parallel tracks extending in a first direction, and a second set of parallel tracks and a third set of parallel tracks extending in a second direction, the second direction being substantially perpendicular to the first direction, the first, second and third sets of parallel tracks being arranged in a grid pattern to define a first set of grid cells, each grid cell of the first set of grid cells having a dimension extending in the first direction and a dimension extending in the second direction to define a first type grid cell opening;
• ii) a second portion including one or more grid cells of the first set of grid cells and a second set of grid cells, the second set of grid cells being defined by the first and second sets of parallel tracks, each grid cell of the second set of grid cells having a dimension extending in the first direction and a dimension extending in the second direction to define a second type grid cell opening;
• and
• B) a plurality of upright columns supporting the track system and arranged to form a plurality of vertical storage locations for one or more storage containers to be stacked between the upright columns;
• wherein in the first direction, the dimension of the second type grid cell opening is a multiple of the dimension of the first type grid cell opening, and in the second direction, the dimension of the first type grid cell opening is substantially equal to the dimension of the second type grid cell opening;
• and
• wherein one or more of the second set of grid cells in the second portion is neighboured by at least two grid cells of the first type of grid cells in the first direction and a single grid cell of the first type of grid cell in the second direction.