| 摘要 |
1. An external screening device for a pivotable skylight window with a horizontal axis of rotation (2) in a center area of the main frame and the sash of the window, comprising a continuous web (5) of a flexible screening material which is wound on a roller (11) situated at an upper horizontal frame member of the window and is connected at its free end with a bottom bar (7) guided in side guide rails (9, 10), said bottom bar being connected for unrolling the web (5) over a cord drive (14, 15) with a drive unit (12, 13) which is also positioned in connection with the upper horizontal frame portion, said side guide rails (9, 10) for the bottom bar (7) extending along the parts (3) of the frame side portions placed above the axis of rotation (2) and the parts (4) of the sash side portions placed below the axis of rotation (2), characterized in that an essentially rod-shaped support device (8, 18) is attached to the screening web (5) to extend across the web (5) essentially parallel to the bottom bar and guided in said side guide rails (9, 10), said support device (8, 18) being positioned, in a position of use for the screening device, at or close to the axis of rotation (2) in parallel thereto. 2. A screening device according to Claim 1, characterized in that the support device comprises a stiffening ledge (8) fastened to the web (5) at a distance from the bottom bar (7) corresponding essentially to the distance of the axis of rotation (2) from a lower horizontal sash element of the window. 3. A screening device according to Claim 1, characterized in that the support device comprises a ledge (18) displaceable with respect to the web (5) and releasable coupled with the bottom bar (7), whereby in the side guide rails (9, 10) in the area opposite the axis of rotation (2) means (21-24; 26-29) are provided for releasing the interconnection between the bottom bar (7) and said ledge (18) and arresting of the latter during continuous unrolling movement of the bottom bar (7). 4. A screening device according to Claim 3, characterized in that the ledge (18) is arranged across the web without any other connection therewith than said releasable coupling to the bottom bar. 5. A screening device according to Claim 3, characterized in that the ledge (18) is designed as a double or slotted ledge profile with two parts (18a, 18b) placed on either side of the web. 6. A screening device according to any of the preceding Claims, characterized in that means for retightening the web (5) in the fully drawn position are attached to the drive unit (12, 13) or the cord drive (14, 15) for the unrolling movement. 7. A screening device according to Claim 6, characterized in that the drive unit for the unrolling movement is an electric motor with means comprising a sensing device for switching-off the motor current in said fully drawn position of the screening web (5) during simultaneous securing of the retightening of web. 8. A screening device according to Claim 7, characterized in that said sensing device comprises an over current sensor for the motor current in connection with means for short reversal of the motor after said switching-off of the motor current. 9. A screening device according to Claim 7, characterized in that said sensing device comprises a contact member (30) arranged at the lower part of a side guide rail (10) and actuated by a member (31) connected with the web. 10. A screening device according to Claim 9, characterized in that said contact member is a Hall member. 11. A screening device according to one of the preceding Claims, characterized in that in the vicinity of and parallel to the roller (11) a rod-shaped or cylindrical device (33) is provided for retightening and smoothing the web (5) during rewinding. |
