Conveyor belt

A conveyor belt comprising:

• a support structure;
• a mobile belt which is supported by said support structure and extends between a first end and a second end along a movement direction to form a transport plane;
• a plurality of rollers that are associated to said support structure and are suitable to support and move said mobile belt along a closed path, said plurality of rollers comprising a drive roller and at least one idler roller, wherein said plurality of rollers comprises two further idler rollers, wherein:
• two first rollers of said plurality of rollers are placed at the same height (H1), one at said first end and one at said second end so as to impose on the mobile belt a horizontal section (P1) in said closed path, the horizontal section (P1) defining said transport plane;
• and
• two second rollers of said plurality of rollers are placed in proximity of said second end lower than the two first rollers, said two second rollers being staggered both horizontally and in height respectively at an intermediate height (H2) and at a lower height (H3), so as to impose on the mobile belt—in cooperation with the roller arranged at the second end—a double S-shaped section (P2) in the closed path, said closed path being completed by an inclined section (P3) connecting the double S-shaped section (P2) to the horizontal section (P2) at the roller placed at the first end,
• wherein the roller placed at the first end and the roller placed at said lower height (H3) are rotationally supported directly by said support structure in fixed positions, while the roller placed at the second end and the roller placed at said intermediate height (H2) are rotationally supported by a mobile frame which is slidingly associated to said support structure to be moved between a retracted position, in which the roller placed at said second end is positioned completely inside said support structure, and an extracted position, in which the roller placed at said second end protrudes outside said support structure,
• wherein, in the passage between said retracted position and said extracted position, the length of said horizontal section (P1) varies and is compensated by an equivalent variation in length of the double S section (P2), due to the fact that the roller placed at said intermediate height (H2) integrally follows the movements of the roller placed at the second end.