Patent ID: 8113255

Claim:
A device for positioning the conveyor belt moving in thermal treatment machines for filaments, comprising: a pressurized chamber ( 1 ) having a first end and a second end; a conveyor belt ( 2 ) traversing said pressurized chamber ( 1 ); first and second bellows ( 4 ) connected to the pressurized chamber ( 1 ) respectively at the first and second ends of the pressurized chamber ( 1 ); a first movable unit comprised of one of a movable door ( 3 ) and a movable frame, the first movable unit connected to the first end of the pressurized chamber by said first bellows ( 4 ), through which first movable unit the conveyor belt circulates; a first sealing head mounted on the first movable unit and closing the first end of the pressurized chamber; a second movable unit comprised of another one of a movable door ( 3 ) and a movable frame, the second movable unit connected to the second end of the pressurized chamber by said second bellows ( 4 ), through which second movable unit the conveyor belt also circulates; a second sealing head mounted on the first movable unit and closing the second end of the pressurized chamber, each said sealing head comprising a pair of superposed horizontal rollers ( 5 , 6 ) pressed against opposite surfaces of the conveyor belt ( 2 ); a positioning means ( 8 ) arranged to change a position of the movable unit; and position control means ( 9 ) acting on a region immediately adjacent each sealing head to detect a position of the conveyor belt at the region.