Ventilation device, has air outlet opening closure parts operated using pairs of cables extending around different diameter surfaces of cable wheel

摘要

Each adjustable closure part in the air outlet openings (5) includes a cable wheel (24) rotatably mounted in the closure part casing. The tensile force exerted by a cable connected to an electric actuator is transmitted to a large diameter runner surface on the wheel and a second cable extending in the same direction engages with a small diameter runner surface on the wheel on the opposite side of the wheel rotation axis to the large diameter runner surface, in order to exert a force to the wheel opposing that exerted by the actuator cable. The second cable has one end connected to a closure part lifting mechanism so that the tensile force for positioning the closure part is converted into a lower tensile force applied to the actuator cable. The actuator cable stroke is reduced to that of the second cable so that the tensile force exerted by the actuator is reduced by a factor equal to the transmission ratio defined by the actuator cable stroke to second cable stroke ratio. Air is introduced into a room (16) via adjustable inlet openings, preferably valves (1) located in a ceiling (4), and removed via essentially vertically movable closure parts mounted in ceiling fixtures which contain openings in communication with an air supply region. The closure parts are driven by a tensile force exerted by preferably steel cables connected to an external electric actuator.