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Patent Searching and Data


Title:
ADJUSTABLE WINDOW
Document Type and Number:
WIPO Patent Application WO/2023/152243
Kind Code:
A1
Abstract:
There is provided a window assembly (1) comprising a frame (2), an upper sash (3) and a lower sash (4), where the upper sash (3) is vertically adjustable to provide an opening (14), where the upper sash (3) is vertically adjustable between an upper end position and a lower end position, and where the lower sash (4) is a) tiltable movable to provide a second opening or not vertically adjustable; or b), where the assembly (1) comprises adjustment means for adjusting the upper sash (3) in the vertical direction, and where the upper sash (3) has a upper first horizontal surface (8), and where the lower sash (4) has an upper second horizontal surface (13), said adjustment means comprising at least one vertical rack (15) attached to a stile (5, 6) of the upper sash (3), driving means (17), transmission means (18) arranged to transmit drive to a driving pinion (16) that interacts with the rack (15), where the upper sash (3) can be vertically adjusted such that the first upper surface (8) and the second upper surface (13) are at the same height.

Inventors:
SPENCER MAUD (SE)
SVENSSON LINUS (SE)
BOLIN ANDREAS (SE)
Application Number:
PCT/EP2023/053231
Publication Date:
August 17, 2023
Filing Date:
February 09, 2023
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SVALSON AB (SE)
International Classes:
E05D15/16; E05D15/48; E05F15/67
Foreign References:
TWM541502U2017-05-11
US20200181974A12020-06-11
JPH02103487U1990-08-16
Attorney, Agent or Firm:
NORÉNS PATENTBYRÅ AB (SE)
Download PDF:
Claims:
CLAIMS

1. A window assembly (1) comprising a frame (2), an upper sash (3) and a lower sash (4), where the upper sash (3) is vertically adjustable between an upper end position and a lower end position, such that an opening (14) is provided when the upper sash (3) is in the lower end position, and where the lower sash (4) is a) tiltable movable to provide a second opening or b) not be openable, where the assembly (1) comprises adjustment means for adjusting the upper sash (3) in the vertical direction, and where the upper sash (3) has a first upper surface (8), and where the lower sash (4) has an second upper surface (13), said adjustment means comprising at least one vertical rack (15) attached to a stile (5, 6) of the upper sash (3), driving means (17) comprising an electrical motor, transmission means (18) arranged to transmit drive from the driving means (17) to a driving pinion (16) that interacts with the rack (15), where the upper sash (3) can be vertically adjusted such that the first upper surface (8) and the second upper surface (13) are at the same height.

2. The window assembly according to claim 1 where the first upper surface (8) and the second upper surface (13) are at the same height when the upper sash (3) is in the lower end position.

3. The window assembly according to claim 1 or 2 where the rack (15) has an upper end (20) that protrudes above the first upper surface (8) and where the driving pinion (16) is arranged to interact with the protruding upper end (20) of the rack (15) when the upper sash (3) in its lower end position. The window assembly according to any one of claims 1 to 3 where the stiles (5,6) of the upper sash (3) are arranged to slide along the outside of a lip (21) extending from the frame (2), where the driving pinion (16) is arranged on the inside of the lip (21) and interacts with the rack (15) through an opening (26) in the lip (21). The window assembly according to claim 4 where the driving pinion (16) is comprised in a housing (22) which mates to the opening (26) in the lip. The window assembly according to any one of claims 1 to 5 where the teeth of the rack are directed inwards. The window assembly according to any one of claims 1 to 6 where there is one rack arranged on each of the two stiles of the upper sash and each rack is driven by a separate driving pinion. The window assembly according to claim 7 where the transmission means comprises a horizontal axle which transfers drive to the two driving pinions, said horizontal axle being arranged on an upper horizontal part of the frame. The window assembly according to any one of claims 1 to 8 where the driving means is a tubular motor which is horizontally arranged a horizontal upper part of the frame. The window assembly according to any one of claims 1 to 9 where the driving pinion is arranged above the lower sash and inside the upper sash and where the teeth of the rack is directed inwards. A window assembly according to any one of claims 1 to 10 which is arranged in a building having an inner floor such that the upper sash 3 can be vertically adjusted such that the first upper surface and the second upper surface are at the same height which height is from 100 cm to 140 cm from the inner floor of the building.

Description:
ADJUSTABLE WINDOW

Field of the invention

This invention relates to a window that can be vertically adjusted and opened.

Background

Windows with two vertically moving sashes ("sash windows") are used in for example the USA and the UK. These are typically maneuvered by hand.

There are examples of powered sash windows. However, powering mechanisms are often bulky and visible from the inside, which is a disadvantage. Moreover, when mounted in a window frame such powering mechanism often results in a bulky frame which makes the frame very large in relation to the glassed area.

It is desirable that the window is serviceable from the inside when mounted in an apartment building and that that all spare parts can be replaced from the inside.

It is an object of the invention to provide a large, powered, vertically openable window which as much glassed area as possible, which is also safe and reliable to operate.

Summary of invention

In a first aspect of the invention there is provided a window assembly comprising a frame, an upper sash and a lower sash, where the upper sash is vertically adjustable between an upper end position and a lower end position, such that an opening is provided when the upper sash is in the lower end position, and where the lower sash is a) tiltable movable to provide a second opening or b) not openable, where the assembly comprises adjustment means for adjusting the upper sash in the vertical direction, and where the upper sash has a upper first horizontal surface, and where the lower sash has an upper second horizontal surface, said adjustment means comprising at least one vertical rack attached to a stile of the upper sash, driving means comprising an electrical motor, transmission means arranged to transmit drive from the drivning means to a driving pinion that interacts with the rack, where the upper sash can be vertically adjusted such that the first upper surface and the second upper surface are at the same height.

The first upper surface and the second upper surface are preferably at the same height when the upper sash is in the lower end position.

In various embodiments, the rack has an upper end that protrudes above the first upper surface and the driving pinion is arranged to interact with the protruding upper end of the rack when the upper sash in its lower end position.

In general, this makes it possible to arrange the driving pinion above the lower sash, and generally out of the way of the lower sash. This also makes it possible to arrange the driving pinon and the rack in such a way that the frame can be made as thin as possible, in order to provide maximum glassed area. This arrangement also makes it possible to make the lower sash openable.

The stiles of the upper sash may be arranged to slide along the outside of a lip extending from the frame, where the driving pinion is arranged on the inside of the lip and interacts with the rack through an opening in the lip. This prevents outside air and water to enter the inside, in particular this protects the transmission means and the driving pinion.

The driving pinion may be comprised in a housing which mates to the opening in the lip. This provides further insulation between the outside and the inside.

The teeth of the rack are preferably directed inwards.

There may be one rack arranged on each of the two stiles (left and right) of the upper sash and each rack is driven by a separate driving pinion. This prevents the upper sash from getting stuck during vertical movement.

The transmission means may comprise a horizontal axle which transfers drive to the two driving pinions, said horizontal axle being arranged on an upper horizontal part of the frame. This provides a slim frame and a large glassed area.

The driving means may be a tubular motor which is horizontally arranged on a horizontal upper part of the frame. This provides a slim frame and a large glassed area.

In various embodiments, the driving pinion is arranged above the lower sash and inside the upper sash and the teeth of the rack is directed inwards.

It is preferred that the window assembly is arranged in a building having an inner floor such that the upper sash can be vertically adjusted such that the first upper surface and the second upper surface are at the same height which height is from 100 cm to 140 cm from the inner floor of the building.

The two upper surfaces then provide a comfortable surface to lean on, for user looking out the window. Fig. 1 shows a window assembly seen from the outside.

Fig. 2 is a schematic drawing of a window assembly seen from the inside with the upper sash in the upper end position.

Fig. 3 is a schematic side view of parts of the window assembly of Fig. 2 seen from the left side.

Fig. 4 is a schematic drawing of the window assembly of Fig. 3 seen from the inside.

Fig. 5 is a schematic drawing of a window assembly with the upper sash in the lower end position.

Fig. 6 is a schematic side view of parts of the assembly of Fig. 5 seen from the left side.

Fig. 7 is a schematic drawing of the window assembly of Fig. 6 seen from the inside.

Fig. 8 shows a part of a window assembly.

Fig. 9 shows a part of a window assembly

Fig. 10a and 10b shows sections of a part of a window assembly.

Fig. 11 shows a part of a window assembly seen from below and from the outside.

Fig. 12 shows a part of a window assembly of Fig. 11. .

Figs 13-14 are schematic views of a window assembly.

Detailed description

Relative position such as "upper", "lower", "inner", "outer", "inwards", "outwards", "left" and "right" are used herein as would be used by a person standing in a building and looking out the window assembly 1 which is mounted in a building, i.e. having the point of view of the person in Fig. 1. For example, in Figs 2, 4 and 5, "left" corresponds to the left side of the drawing.

With reference to Figs 1-7 and 13-14, window assembly 1 is intended to, and adapted to, be arranged in an opening in a building, in particular in an outer facade. The window assembly 1 comprises frame 2 which may be made from metal or wood, or plastic such as extruded PVC, or combinations thereof. In general, the various parts of the window assembly 1 that is not glass may be made from wood, metal or plastic such as extruded PVC, or combinations thereof. The frame 2 can be used to fit the assembly 1 in an opening in a wall of the building and attaching the window assembly 1 to the building.

Window assembly 1 comprises upper sash 3 and a lower sash 4. The upper sash 3 comprises left stile 5 and right stile 6 and upper rail 7, and lower rail. A first glass pane (not shown) is held in the upper sash 3. The upper sash 3, preferably the upper rail 7 of the upper sash 3, has a first upper surface 8 which may be horizontal. Lower sash 4 comprises left and right stiles 9, 10 and upper rail 12 and lower rail 36. A second glass pane (not shown) is held in the lower sash 4. The lower sash 4, preferably the upper rail 12 of the lower sash 4 has a second upper surface 13 which may be horizontal.

In general glass panes are not shown in the figures (with the exception of Fig. 10a). Glass panes may be single, double or triple. Fig. 10a shows an example of triple glass panes 30, 31, 32 in upper sash 3.

The upper sash 3 is preferably arranged outside relative to lower sash 4. The upper sash 3 and the lower sash 4 may define the outside and the inside of the window assembly 1, respectively. Having the upper sash 3 on the outside decreases the risk of water entering the assembly 1. It is also safer to have the vertically adjustable sash 3 outside lower sash 4 in order to prevent injury when adjusting the upper sash 3. Moreover, the driving means 17 and transmission means 18 can be placed in the space above the upper sash 4 without protruding into the room of the building where the assembly 1 is used

The upper sash 3 is vertically adjustable, in order to provide an opening 14. Preferably upper sash 3 is able to slide vertically along a part of the frame 2, for example lip 21 as described below.

The upper sash 3 has an upper end position and a lower end position. When the upper sash 3 is in the upper end position, the upper sash 3 is closed and there is no opening 14. There is an opening 14 at least when the upper sash 3 is in the lower end position or when the first and second upper surfaces 8, 13 are at the same height. Preferably the upper sash 3 is stepless vertically adjustable such that the upper sash 3 can be positioned and kept still at any vertical position between the upper end position and the lower end position.

The lower sash 4 may be such that it is not possible to open it. However, in various embodiments the lower sash 4 may be able to provide a second opening. The lower sash 4 may be such that it is not vertically adjustable (unless it is completely detached and removed from assembly 1). The lower sash 4 may be openable by tilting it vertically (or horizontally) inwards. For example, lower rail 36 of lower sash 4 may be attached to lower horizontal part 37 of frame 2 with hinges 38. This makes it possible to tilt upper part of lower sash 4 into the room. This makes it easy to clean the outside of the glass pane of the lower sash 4. Lower sash 4 may for example be attached to the frame 2 with hinges 38 and an elbow fitting, such as for example Assa Fix 831 from Assa Abloy. It may be possible to fully detach the lower sash 4, for example if it needs to be replaced, but mainly the lower sash 4 should remain closed for safety reasons. In some embodiments the lower sash 4 may be arranged in frame 2 such that it is releasable from frame 2, for example if the lower sash 4 needs to be replaced.

An adjustment means is used to vertically adjust the upper sash 3. The adjustment means preferably comprise at least one vertical rack 15 attached to upper sash 3, preferably a stile 5,6 of the upper sash 3. The vertical rack 15 is driven by a driving pinion 16. The rack 15 has teeth 41. Preferably there are two vertical racks 15, one on each stile (left stile 5 and right stile 6) of the upper sash 3. Each rack 15 is then driven by a separate driving pinion 16, a left driving pinion (shown in Fig. 2) and a right driving pinion 16 (not shown). An advantage with using one rack 15 on each side of the sash 3 is that simultaneous vertical movement of the right and left sides of upper sash 3 is ensured, which avoids the upper sash 3 getting stuck. The driving pinion 16 for the left rack 15 may be placed such that it is left of the upper sash 3 and the lower sash 4. In a corresponding manner, a driving pinon for the right rack 15 may be arranged right of the upper sash 3 and to the right of lower sash 4. However, in a preferred embodiment schematically shown in Figs.13-14 and in more detail in Figs. 8-10, the driving pinion 16 is placed above the lower sash 4 and inside relative to the upper sash 3. In a preferred embodiment the driving pinion 16 is arranged so that it located in a space immediately above lower sash 4, preferably above a stile 9, 10 of the lower sash 4 as shown in Figs. 8, 10a, 10b and Figs. 13-14. Hence, the driving pinion 16 may be arranged in the space that the lower sash 4 projects upwards. It is preferred that the driving pinion 16 interacts with upper end 20 of rack 15 that protrudes above upper surface 8, as described below. 10b shows how the upper sash 3 has been lowered such that the upper surfaces 8, 13 are at the same height.

The rack 15 may be placed on the left side of the left stile 5 or on the right side of the right stile 6 of the upper sash 3 as shown in Figs 2-7 and 9 (or both). Alternatively, the rack 15 may be attached on the inside of the stile 5, 6, or form a part of stile 5, 6. It is preferred that the teeth 41 of the rack 15 are directed inwards. The driving pinon 16 is preferably arranged inside relative to the rack 15. This provides more glass surface since the driving pinon 16 can be arranged inside relative to the rack 15. This provides a slimmer design of the assembly 1 and more glassed area.

The adjustment means comprises driving means 17. The driving means 17 preferably provides rotational drive. The driving means 17 is preferably an electrical motor. In a preferred embodiment the driving means 17 is placed in the upper part of the assembly 1, preferably above the upper position of the upper sash 3. For example, the driving means 17 may be attached to upper horizontal part 25 of the frame 2. This makes it possible for one single driving means 17 to drive both right and left racks 15 and to provide a slim design for assembly 1. In a preferred embodiment, shown in Figs. 11-12, the driving means 17 is a tubular motor (electrical tubular motor) which is horizontally mounted on the upper horizontal part 25 of the frame 2. However, the electrical motor may also be a worm gear motor, for example a worm gear motor placed in left or right side of frame 2. In various embodiments, the driving means 17 may be manually powered, such as for example with a crank. For example, it may be possible to vertically adjust upper sash 3 in case of a power failure.

The assembly 1 comprises transmission means 18 arranged to transmit drive from the driving means 17 to the driving pinion 16 that interacts with the rack 15. In a preferred embodiment transmission means 18 transmits drive to a left and right driving pinion 16 that interacts with left and right racks 15. It is preferred that driving pinion 16 is arranged below the driving means 17.

The transmissions means 18 makes the driving pinion 16 rotate. The driving pinon 16 interacts with the rack 15 so that the rack 15 moves up or down with the rotation of the driving pinon 16, which moves the upper sash 3 vertically.

An example of an arrangement of driving means 17 and transmission means 18 is shown in Figs. 11-12. The transmission means 18 may for example comprise left and right upper cogwheels 24ab that is turned by the driving means 17 and left and right toothed belt, gear belt or a roller chain 19ab that transmits rotation from the upper cogwheels 24ab to left and right driving pinions 16 that each interacts with left and right the racks 15.

Preferably the upper sash 3 can be controlled to remain at any vertical position between the upper end position and the lower end position.

When the driving means 17 is an electric motor, the driving means 17 may be controlled by a control device, which may comprise any suitable combination of hardware and software, for example control circuitry. The control device may be able to control the direction of movement of the upper sash 3 (up/down). The control device may be able to control the speed of movement of the upper sash 3. The control device may comprise a sensor that detects the current vertical position of the upper sash 3. The sensor may for example be a rotary encoder located on rotating part of the driving means 17, transmission means 18 or the driving pinon 16. The sensor may be able to detect the vertical position of the rack 15 or other part of upper sash 3.

The control device may comprise a user interface, such as one or more buttons or a touch display, which a user can use to adjust the vertical position of the upper sash 3. A user may be able to select a vertical position for the upper sash 3 or a direction of movement of the upper sash 3 (up or down). Furthermore, the control means may be such that interacting with a first "down" button makes the upper sash 3 go down to the lower end position or a position where the first upper surface 8 and the second upper surface 13 are at the same height. Pressing an "up" button may make the upper sash 3 go to the upper end position. The control device may be able to provide a signal to the adjustment means, preferably the driving means 17, with a wire, or wirelessly.

The control device and the adjustment means may be configured to stop downwards vertical adjustment (opening) of the upper sash 3 when the first upper surface 8 and the second upper surface 13 are at the same height. For example, if the lower end position is a position such that the first upper surface 8 is below the position of the second upper surface 13, the upper sash 3 may nevertheless have a predetermined stopping position where the upper surface 8 is at the same height as the second upper surface 13.

The control device and the adjustment means may have various safety features. There may be a predetermined stopping position which leaves a comparatively small opening 14 with a height of from 1 to 15 cm. Such an opening may be used for ventilation. Such an opening 14 is quite safe because it will be typically located far above children and animals, and also difficult to enter from the outside of the building.

Additionally, there may be various features that prevent risk of pinching when closing the window. The adjustment means may for example be able to stop upwards movement of the upper sash 3 if a high load is detected. The adjustment means may be configured to then stop and reverse movement.

It is an advantage if the upper sash 3 can be vertically adjusted such that the first upper surface 8 and the second upper surface 13 are at the same height. This provides comfortable use as seen in Fig. 1. The assembly 1 then provides a "balcony feel" such that a large opening 14 at a convenient height is provided to the user. The first upper surface 8 and the second upper surface 13 may have a combined width of at least 10 cm, more preferably at least 15 cm, when the first and second upper surfaces 8, 13 are at the same height. This makes it possible to briefly place objects 50 on the combined surfaces, for example saucer as seen in Fig. 1. The distance between the first upper surface 8 and the second upper surface 13 is preferably at most from 1 to 5 mm when the first upper surface 8 and second upper surfaces 13 are at the same height.

Preferably the first upper surface 8 and the second upper surface 13 are at the same height when the upper sash 3 is in the lower end position. An advantage with this is at the first and second upper surfaces 8, 13 will automatically be at the same height when the upper sash 3 is at the lower end position. Importantly, a wide combined surface is provided to the user while also a large opening 14 is provided as seen in Fig. 1.

In a preferred embodiment the rack 15 has an upper end 20 that protrudes above the first upper surface 8 of the upper sash 3 and where the driving pinion 16 is arranged to interact with the protruding upper end 20 of the rack 15 when the upper sash 3 is its lower end position, as seen in Figs 6, 7, and 9. This makes it possible to arrange the driving pinon 16 above the lower sash 4. It is preferred that the driving pinion 16 is located above the upper surface 13 of the lower stile 4. This makes it possible to make the lower sash 4 tiltable openable. This may also make it possible to let the lower sash 4 have the same width as the upper sash 3.

The assembly 1 may have an outside ("cold side" in cold climates) and inside ("warm side" in cold climates) where the assembly 1 has weather and /or temperature proofing to prevent outside air, dust, or noise to enter the building, or to prevent seepage of water. The assembly 1 is preferably weatherproof such that water and cold air cannot enter from the outside to the inside. For example, lip 21 (described below) serves to prevent cold air to enter to the inside between the interface between the upper sash 3 and the frame 2. When lower sash 4 is openable, lower sash 4 may be arranged to close against lip 21. Various parts of frame 2 (including lip 21) upper sash 3 and lower sash 4 (when openable) may have weather strips or weather seals, in particular where upper sash 3 interfaces with frame 2 or where lower sash 4 interfaces with frame 2. It is preferred that the various parts of the adjustment means are on the inside as far as possible, in order to make them accessible for service and also protect those parts from humidity. It is preferred that the upper sash 3 is on the outside of the assembly 1.

In a preferred embodiment, an example of which is seen in Figs. 8 and 9, a part of the upper rail 7 and the stiles 5, 6 of the upper sash 3 may be arranged to slide along the outside of a vertical lip 21 that extends from the frame 2 towards the opening 14. The lip 21 provides isolation and works like a weather strip. The lip 21 may have a thickness of from 1 to 20 mm more preferably from 2 to 15 mm The lip 21 may be made of metal, wood or plastic, where metal is preferred, and a combination of metal and wood is even more preferred. The lip may comprise an outer metal layer and an inner wood layer. The wood layer provides isolation from cold. The side of lip 21 that is facing driving pinion 16 may have a recess for receiving the driving pinion 16, in particular if the thickness of the lip so requires. The lip 21 may be attached to the frame 2 with an attachment means 40 shown in Figs. 10a and 10b. The lower sash 4 may be possible to open as described herein and then it may be able to close against inner side of lip 21. Hence, lip 21 may extend along upper rail 7, along left and right stiles 5,6 of upper sash 3, along left and right stiles 9, 10 of lower sash (Figs 9 and 10) and also along the lower rail 36, This provides a sealed window where upper sash 3 seals against the outer surface of lip 21 and lower sash 4 seals against inner surface of lip 21.

As seen in Figs. 8-9 the driving pinon 16 may be arranged on the inside of the lip 21 and arranged to interact with the rack 15 through an opening 26 in the lip 21.The driving pinion 16 may be comprised in a housing 22 which mates to opening 26 in the lip 21 as shown in Fig. 9, preferably housing 22 mates to the inside of opening 26. This prevents cold air and water from entering the assembly 1 from the outside trough opening 26. Fig. 8 shows the driving pinion 16 without the housing 22.

Opening 26 may be arranged in lip 21 such that an edge 42 of lip 21 is arranged between the opening 26 and the center of the window area. This provides insulation against water and wind. In Figs. 8-9 the drive is transferred from chain 19 to driving pinion 16 via lower cog wheel 28 which in coupled to pinion driving gear 29 on the same shaft. Pinion driving gear 29 may be inside housing 22 together with driving pinion 16, whereas lower cog wheel 28 is outside housing 22 as seen in Fig 9.

Fig 8-9 and fig 10b also show how upper end 20 of rack 15 protrudes above the first upper surface 8 of upper sash 3 and how the driving pinion 16 interacts with the upper end 20 of the rack 15 when the first and second upper surfaces 8,13 are at the same height, which preferably is the lower end position of the first upper surface 8.

The upper sash 3 may be counterbalanced by at least one sash spring 27. The upper sash 3 may be heavy 3 and one or more sash springs 27 reduces load on the adjustment means. Fig. 10a is a partial section drawing showing an arrangement of the rack 15, driving pinion 16 and lip 21. The at least one sash spring 27 may preferably be arranged in close proximity to the rack 15 and outside relative to the rack 15 as seen in Fig. 10, in particular when the rack 15 is arranged on the left of the left stile 5 and on the right side of the right stile 6. Preferably the at least one sash spring 27 may be arranged in a pocket formed by the rack 15, the short ends of glass panes 30, 31, 32 of the upper sash 3 and the frame 2 as seen in Fig. 10.

With reference to Figs 11-12, when there is one rack 15 on each side of the upper sash 3, where each rack 15 is driven by one driving pinon 16, the transmission means 18 may comprises a horizontal axle 23 that transfers drive to each of the of the driving pinions 16 as seen in Fig. 11 and 12, in particular when the driving means 17 is placed in the upper part of the assembly 1, preferably above the upper position of the upper sash 3, for example on the upper horizontal part 25 of the frame 2. Axle 23 may drive a left upper cogwheel 24a for left chain 19a and right upper cogwheel 24b for right chain 19b.

The driving means 17 is preferably a tubular motor as described herein. The horizontal axle

23 may be attached to the upper horizontal part 25 of the frame 2 with bearing 33. Transmission means 18 may comprise at least one transmission cog, such as transmission cogs 34 and 35, which transfers rotation to the axle 23.

In a preferred embodiment, the window assembly 1 is arranged in a building having an inner floor such that the upper sash 3 can be vertically adjusted such that the first upper surface 8 and the second upper surface 13 are at the same height which height is from 80 cm to 170 cm, more preferably from 100 cm to 140 cm, even more preferably from 100 cm to 120 cm from the inner floor of the building. This provides a suitable safety distance from the floor while providing a comfortable opening 14 which provides the feeling of a "balcony", as seen in Fig. 1. When the first and second upper surfaces 8, 13 are at the same height there is a comfortable surface provided to the user. For example, as seen in Fig, 1, a user can rest the arms on the combined upper surfaces 8,13 and place an object 50 on the combined upper surfaces 8, 13.

In general, various parts of adjustment means such as the driving means 17 and the transmission means 18 may be covered by panels to hide them and to provide a flat surface, and also prevent injuries. The panels may for example be attached to the frame with magnets. The panels may be made from wood.

The assembly 1 is preferably serviceable from the inside such that the lower sash 4, the driving means 17, the transmission means 18, sash springs 27 and other parts can be serviced or replaced from the inside. The upper sash 3 may also be replaceable from the inside.

The window assembly 1 may have any suitable dimensions, for example a height of from 100 cm to 300 cm, more preferably from 130 cm to 240 cm. The height of the upper sash 3 may be, for example, from 40 cm to 120 cm and the height of the lower sash 4 may be from 50 to 130 cm. The height of the upper sash 3 is preferably lower than the height of the lower sash 4.

The window assembly 1 may have a width of from 80 cm to 300 cm more preferably 100- 200 cm. It is an advantage if the upper rail 7 and lower rail of the upper sash 3 and the upper rail 12 of the lower sash 4 are as thin as possible as these will be in the line of sight. The glassed area may be at least 75 %, more preferably at least 78 % and most preferably at least 80 % of the total area of the window assembly 1. % glassed area is determined by dividing the visible glass area seen with the total visible are of the assembly 1 including glass and frame (seen from the outside or the inside, and before the assembly 1 is mounted in a building).