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(11) | EP 2 025 849 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Device driving vent covers, especially for smoke extractor flap |
| (57) Device includes a link mechanism of the drive mounted inside the venting opening
between the fixed frame and the swinging frame, having an arm (7) connected by the
base articulation (8) with the fixed frame at the side of the hinge (5) and a piston
actuator (9) mounted in an articulating way between the arm (7) and the swinging frame.
The arm (7) of the drive mechanism consists of many links, which are connected by
chain articulations (15) and are provided by bottom and upper stops. The bottom stops
limit the relative downward deflection of the links to keep the rectilinear form of
the arm (7), and the upper stops limit the upward deflection of the links, letting
the arm (7) to assume the form of an open polygon. The piston actuator (9) is firmly
fixed to the end link of arm (7), and is located below and at a distance from the
pins of the chain articulations (15) in which its cylinder adheres to all of them
when the arm (7) is rectilinear. When the venting cover is being opened and is partly
open in position II at approximately 45° from level, the first link of the arm (7)
leans against the base element of the fixed frame, while in the fully open position
(III) determined by the upper stops of the links when the piston rod is completely
extended, the end link assumes a position which is above (b) and outside (c) the axis
of the hinge (5).
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