An extensible flat belt conveyor has a fixed section (1) and at least two extension sections (2) and (3). A chain (18) is carried over sprockets (21) and (22) on the portion (2) adjacent the fixed section (1), and its lower traverse is fastened to the fixed section while its upper traverse is fastened to the movable section (3). When a chain sprocket (22) is driven the movable section (3) travels twice as far and as fast as the section (2). A control module (25) is carried on the extending end of movable section (3), and is wired back to the fixed section (1) by an electrical cable (30) which extends through saddles (28) outstanding from the chain (18).
