Patent ID: 8757201

Claim:
Device for regulating the airflow in an air damper, comprising: a twist sleeve of flexible material, having a cross section which substantially conforms to an outer tube in which the flow takes place, one end of the twist sleeve being disposed on an inner side of the outer tube and an other end of the twist sleeve being disposed in a tube sleeve which is rotatable under an axial displacement controlled in relation to the rotation, an outer diameter of the tube sleeve being somewhat smaller than an inner diameter of the outer tube, so that the tube sleeve slides easily in the outer tube, wherein the tube sleeve is provided with a helical slot with teeth along a first edge, and wherein the rotation of the tube sleeve is achieved by an operating apparatus configured to pull round the tube sleeve, at the same time as the tube sleeve moves axially, and wherein the operating apparatus includes a gearwheel configured to, when being rotated, cooperate with the teeth in the helical slot to pull around the tube sleeve.