The invention relates to a multi-layer pane unit with a built-in, adjustable light screening device arranged between two plane-parallel glass layers, which at their side edges are kept at a mutual distance from each other by spacer members for airtight edge sealing of the space between the glass layers, a rotatable driving device for the screening device being arranged in said space along one of the side edges thereof for coupling with an external drive unit by means of a rotatable magnet coupling comprising an internal magnet member in driving connection with the rotatable driving device and an external magnet member positioned outside said space in driving connection with the external drive unit, said magnet members being co-axially journaled with poles facing each other on respective sides of an interface section of the airtight sealed space said interface section being formed by a comparatively thin wall part in a member forming part of the edge sealing in connection with a bearing for the external magnet member.

Insulation windows with multi-layer units of this type are known from US patents Nos. 3,201,832 and 3,722,572 as well as from EP 0 749 514 B1 and published Japanese patent application No. 7-194092. It is known in substance from these publications to use power transmission from the external drive unit to the rotable driving device of the screening device by means of a magnet coupling, for which the interface section between the internal and external magnet members is provided by a part of the internal glass layer of the insulation pane unit, resulting in a comparatively pronounced, visible interference with the light area of the window and furthermore sets a comparatively low limit to the thickness of the internal glass layer. In the design known from said Japanese patent application a magnet coupling is used, which is positioned at one end of an elongate housing for the driving device of the light screening device and coaxially with said driving device. In this design, the magnet members are designed as coaxial, tubular magnets, both positioned inwardly with respect to the spacer members providing the edge sealing, such that an input shaft for the external magnet member penetrates the spacer member along one side edge of the pane unit. The use of tubular magnets and a likewise tubular partition wall positioned coaxially between said magnets as well as penetration of the spacer member result in a complicated design, which makes this design less suitable for industrial production.

EP 0 519 972 discloses another design of an insulation window with a built-in light screening device having a direct power transmission from an external drive unit to the rotatable driving device of the screening device, a corner member at one end of the housing of the rotatable driving device forming an airtight passage for a drive shaft for the rotatable driving device. This design requires a comparatively complicated sealing arrangement.

On this background the object of the invention is to provide a design of a multi-layer pane unit of the type stated, in which said disadvantages are eliminated by means of a stable magnet coupling of a simple structure and which does not significantly interfere with the light area.

To meet this object a multi-layer pane unit of the type stated is according to the invention characterized in, that that the external drive unit comprises a transmission device (19) in connection with the member forming part of the edge sealing between an output shaft coupled to the external magnet member and an input shaft substantially parallel to said output shaft for connection to a driving device.

In a preferred embodiment the external drive unit comprises a transmission device in connection with the member forming part of the edge sealing between an output shaft coupled to the external magnet member and an input shaft substantially parallel to said output shaft for connection to a driving device.

As the parallel output and input shafts of the transmission extend in parallel to the glass layers, the pane unit may be mounted in a sash or frame structure of an insulation window without any substantial interference with said sash or frame structure.

In an advantageous embodiment of the pane unit the glass layers with associated edge sealing are fitted in a frame of profile members, which towards the light area of the pane unit form grooves for accommodation of the side edges and glazing beads of the pane unit and part of said transmission device may be accommodated in a transmission housing mounted in an upper part of said groove in continuation of the glazing bead arranged in the groove, the input-shaft being passed through a wall of said transmission housing facing the light area of the window.

Further, the invention relates to an insulation window comprising a multi-layer pane unit as stated above and a surrounding, substantially rectangular sash composed of mutually perpendicular sash members and with said one side edge of the pane unit in connection with an upper sash member.

Further advantageous embodiments of the multi-layer unit according to the invention are described in the dependent claims 2 - 12.

The invention will now be explained in detail in the following with reference to the schematic drawing, in which:

• Fig. 1 shows an embodiment of the insulation window according to the invention, seen from the internal side;
• Figs 2 and 3 are sectional views of the window in Fig. 1 along the section lines II-II and III-III in Fig. 1;
• Fig. 4 is an exploded view of a rotatable driving device for the light screening device for the window in Figs 1 - 3; and
• Figs 5, 6 and 7 show details in the magnet coupling at a larger scale in a second, mirror reversed embodiment.

The insulation window shown in Figs 1 - 3 has a rectangular sash composed of sash members 2, 3, 4 perpendicular to one another. The sash is mounted in an intermediate or main frame 100.

In the sash a multi-layer pane unit 1 is mounted with an adjustable light screening device 5 arranged between two plane-parallel glass layers 6, 7, which are kept at a mutual distance by spacer members 8, 9, 10 preferably in connection with a sealing compound for provision of an airtight edge sealing of the space 11 between the glass layers 6 and 7.

In the embodiment shown, a rotatable driving device 12 for the screening device 1 is positioned in a housing 13 having a cover 13' functioning as a spacer member and forming part of the edge sealing between the glass layers 6, 7. The housing 13 has the form of a U-shaped rail profile with side walls 20 engaging the cover 13' along one sash member 2. The driving device 12 is connected to an external drive unit, which in the embodiment shown has the form of a cord drive 14, by means of a rotatable magnet coupling comprising an internal magnet member 15, which is in driving connection with the rotatable driving device 12, and an external magnet member 16 positioned outside the edge sealing in driving connection with the external drive unit 14. The magnet members 15, 16 are arranged such that their poles face one another, but the magnets 15, 16 are positioned on respective sides of a thin transverse wall 17 in a corner member 18 provided at the end of the housing 13 which faces a sash member 3 perpendicular to the sash member 2 along which the housing 13 extends. The thin transverse wall 17 constitutes a wall part of the airtight sealed space 11 between the glass layers 6, 7.

However, the housing 13 is not absolutely necessary, given the screening device with associated drive device may be mounted in conjunction with a conventional edge sealing profile known per se, optionally with suitable masking of an edge zone of the glass layers to provide a concealed mounting.

The corner member 18 placed at one end of the U-shaped rail profile 13 forms outside the transverse wall 17 a bearing for the external magnet member 16, and, in the embodiment shown in Figs 5 - 7, it also provides a bearing on the opposite side of the transverse wall 17 for the internal magnet member 15. The part of the corner member 18 forming a bearing for the external magnet member is provided with top, bottom and side walls 21, 22, 23 integral with said transverse wall 17. In this manner the external magnet member 16 is journaled in a blind hole, which is sealed with respect to the space between the glass layers 6, 7.

In the embodiment shown in Figs 1 - 4 the corner member 18 may be airtight sealed to the housing 13, which in turn is airtight sealed with the glass layers 6, 7, and thus forms part of the edge sealing of the space 11 between the glass layers 6, 7. Alternatively, the corner member 18' may as shown in Figs 5 - 7 be provided with an end collar 31 having the same contour as the outer contour of the U-shaped housing 13, such that the end collar 31, when positioned against the end of the housing 13 and in combination therewith, may be airtight sealed to the glass layers 6, 7, thus forming an integral part of the edge sealing.

In the embodiment shown, the external drive unit comprises a cord drive 14 mounted on the side 24 of the sash member 3 facing the light area of the window, the external magnet member 16 being connected with this cord drive by a transmission 19 built into the second sash member 3.

The transmission 19 comprises a belt transmission having two mutually parallel shafts 25, each carrying a toothed wheel, and a toothed belt 26 extending over said shafts. The two shafts 25 form an output shaft towards the external magnet member 16 and an input shaft in connection with the cord drive 14, respectively. The two shafts 25 with associated toothed wheels and the toothed belt 26 are accommodated in a housing composed of two parts 19a, 19b and comprising a substantially rectangular rod profile 19c. In this manner the input shaft 25 may in a simple manner be passed through a wall of the rod profile 19c facing the light area of the pane unit with a suitable sealing for connection to the external driving device. Instead of a manually operated driving device in the form of for instance a cord drive the external drive unit may comprise an electric driving device connected to the input shaft 25.

The screening device 1 may for instance comprise a roller blind, a pleated blind or, as in the embodiment shown, a Venetian blind, which in an inoperative position assume a rolled up or folded position by one sash member 2 and may be moved by means of a cord arrangement 27 between the inoperative position and an operative light screening position. The rotatable driving device 12 thus comprises winding reels 28 for the cord arrangement 27, said winding reels 28 being mounted on a shaft 29, which through a reduction gear 30 is connected to the internal magnet member 15.

The reduction gear may, as shown in Figs 5 - 7, be designed as a planet gear, but alternatively a worm gearing may be used, if automatic locking is desired.

The embodiment shown in Figs 5 - 7 is mirror reversed with respect to the embodiment shown in Figs 1 - 4 and shows more details than the more schematic Figs 1 - 4. In particular, an embodiment of the corner member 18 is shown, which comprises a body part 32 connected to the end collar 31 for accommodation of the external magnet member 16 and comprising the transverse wall 17 and said top, bottom and side walls 21, 22, 23. The end collar 31 is provided with a downwards facing tongue 31' and the body part 32 with a bottom section 33 and a covering section 32, said sections constituting together a bearing for the internal magnet member 15.

In this embodiment the multi-layer pane unit with associated magnet coupling and transmission device constitute a complete unit, which in a simple manner may be mounted in an insulation window, either of the type shown in Figs 1 - 4 having a sash or frame comprising wooden profiles, or by mounting of the multi-layer pane unit in a frame of profile members 35, preferably made from aluminium, said profile members being towards the light area of the window provided with grooves 36 having a width which makes it possible to mount the edge part of the pane unit together with a glazing bead profile 37. In this manner the above-mentioned rod profile 19c of the transmission device housing may be designed for mounting in the upper part of the groove 36 instead of a corresponding length of the glazing bead profile.

Fig. 6 shows the insulation window seen from above, the upper parts of the frame and the sash, the adjacent edge sealing and the light screening device with associated driving device and cord drive being removed.

Fig. 7 shows an view of among others the planet gear 30 in an exploded representation.

It should be understood that the invention is not limited to the embodiments shown by way of example. Among others, an electric drive unit built into the second sash member 3 may be used as an alternative to the manual cord drive 14 shown.