Abstract: 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).

Abstract: A method of assembly of a pair of stiles to a core sub-assembly which comprises a pair of rails and an expandable lattice spacer panel interconnecting the rails, which comprises clamping the end rails of the core sub-assembly and separating them from one another so as to expand the lattice spacer core, retaining the end rails in position while positioning stiles with respect to them, joining the stiles at the corners of the end rails, spot-joining the lattice to the stiles, and ejecting the door frames so formed from the machine.