Roof window with a lifting device with a sledge guide having a rail forming part of a side frame reinforcement

Abstract

A roof window (100), particularly for installation in or on a roof surface having an inclination, comprising a primary frame (1) comprising a top frame member, two side frame members, and a bottom frame member, at least one secondary frame (2), a lifting device (10) comprising a sledge (12), a sledge guide (13), a set of arms (14, 15, 16), and a spring assembly (11), wherein the spring assembly (11) is configured to be coupled to the sledge (12), and the sledge guide (13) comprises a first rail (13.1) and a second rail (13.2). At least one of the first rail (13.1) and the second rail (13.2) forms part of a side frame reinforcement element attached to one of the side frame members.

Description

Technical Field

[0001] The present invention relates to a roof window, particularly for installation in or on a roof surface having an inclination, comprising a primary frame comprising a top frame member, two side frame members, and a bottom frame member, at least one secondary frame, a lifting device comprising a sledge, a sledge guide, a set of arms, and a spring assembly, wherein the spring assembly is configured to be coupled to the sledge, and the sledge guide comprises a first rail and a second rail.Background Art

[0002] Windows for installation in an inclined roof surface may be provided in a number of varieties and include more or less complicated operational structures to allow opening of the sash and to fulfil other functions, such as ventilation. Such roof windows include the type hinged at or near the middle (generally designated "pivoting roof windows"), the top-hinged type, and finally the roof windows that are top-hinged during normal operation but in which the sash is able to perform a rotating movement substantially at a centre axis near the middle of the sash, either for cleaning of the outside of the pane mounted in the sash or for providing an alternative manner of operation. Roof windows of the top-hinged type have a first axis of rotation provided by a top hinge arrangement to provide a first operational condition, whereas rotation of the sash in a second operational condition is performed by means of an intermediate frame in which the sash is hinged to provide a secondary axis of rotation. Typically, one hinge of the hinge arrangement will be located at either side of the roof window to define a substantially horizontal axis of rotation.

[0003] Examples of top-hinged windows with a second operational condition are for instance disclosed in Applicant's WO-A-89 / 10460, EP 0 733 126 B1, EP 1 873 323 B1, EP 2 762 665 A2, and WO 2019101281 A1. To make it possible to rotate the window sash approximately 180° to a convenient cleaning position of the pane, the sash structure is connected with an intermediate frame with frame arms, which in the closed position of the window are positioned between the upper parts of the frame and sash side members, and which during normal use of the window as a top-hung window follow the sash side members.

[0004] Furthermore, the opening of a roof window and the force required to operate the window is majorly affected by the inclination of the roof, where the window is installed.

[0005] In roof windows in which the operation takes place either entirely or partially about an axis of rotation at the top, it is known to balance at least part of the weight of the movable components by means of a lifting device which includes a spring to generate the forces needed to balance the weight of the pane carrying sash. The purpose of this arrangement is to facilitate opening of the window, and the dimensions may be chosen so that the spring can retain the top-hinged sash in equilibrium in a desired opening position.

[0006] Such a lifting device is for instance disclosed in the Applicant's WO 2019 / 101281 A1 where a spring assembly acts as a force balancing element to the pane-carrying frame by operating on a lifting arm attached to the frame.

[0007] However, although the lifting device in the above example is to some extent capable of providing the desired force balance, there is still room for improvement.Summary of Invention

[0008] With this background it is an object of the present invention to provide the roof window with an increased design flexibility including a lifting device with the desired movement pattern and simple structure with reduced material consumption.

[0009] This is achieved with a roof window of the kind mentioned in the introduction, which is further characterised in that at least one of the first rail and the second rail forms part of a side frame reinforcement element attached to one of the side frame members.

[0010] A lifting device wherein at least one of the first rail and the second rail forms part of a side frame reinforcement element attached to one of the side frame members has the potential advantages that a separate reinforcement element can be dispensed with, that the total size of the lifting device is reduced while retaining function, and in that the sledge guide is arranged closer to the side frame member which reduces the torque from the spring assembly acting on the frame members.

[0011] Even though reference is made to the first rail forming part of the side frame member the skilled person realizes that it equally corresponds to embodiments wherein the second rail forms the side frame reinforcement.

[0012] The first rail may extend substantially the entire length of the side frame member. By having a first rail that extends substantially the entire length of the side frame member the first rail reinforces the side frame member in substantially its entire length thereby optimizing the reinforcing capabilities of the first side rail. A majority of the rail is not directly configured to act as a sledge guide. The first rail extending the substantially entire length of the side frame may additionally be configured to partially house the spring assembly. This has the potential advantage that the first rail has multiple functionalities i.e. the first rail functions as part of a sledge guide, a reinforcing element and a spring housing, thereby saving both material and parts in the lifting device, while having the further potential advantage of providing a simpler lifting device which is easier and quicker to assemble and install.

[0013] The set of arms may be arranged in many different ways to translate a pull from the spring assembly to an opening of the secondary frame. In one embodiment, the set of arms comprises a lifting arm, a push arm, and a sledge arm. The sledge arm may be attached to the sledge at one connection point and to the lifting arm at another connection point. The push arm may be attached to the sledge guide at yet another connection point and to the lifting arm at yet another connection point. The lifting arm may additionally be attached to the secondary frame at yet another connection point.

[0014] A connection point is in principle defined as a pivot point between any two elements such as between the lifting arm and the push arm, which during normal operation of the roof window i.e. during opening and closing of the window, is configured to perform only a rotating movement.

[0015] The inventors have found that a set of arms comprising a lifting arm, a push arm, and a sledge arm, wherein the sledge arm is attached to the sledge at a connection point and to the lifting arm at another connection point, wherein the push arm is attached to the sledge guide at yet another connection point and to the lifting arm at yet another connection point, and wherein the lifting arm is additionally attached to the secondary frame at yet another connection point provides a balanced lifting device with the desired movement pattern. When a user opens the inclined roof window the lifting device counteracts i.e. balances the gravitational pull that urges the window towards a closed position such that the roof window can maintain a specific opening degree. The inventors have found that the set of arms as described provides a balanced roof window for up to 50 degrees opening relative to a closed configuration of the roof window and particularly suited for opening degrees up to 45 degrees opening.

[0016] "Balanced" is generally to be understood as in that the lifting device provides a pulling force that balances the gravitational pull that urges the open window towards the closed configuration.

[0017] The sledge guide may be attached to the primary frame and the sledge may be slidably connected to the primary frame via the sledge guide.

[0018] The lifting arm may comprise a first lifting arm part and a second lifting arm part. This configuration has several advantages from a manufacturing point of view, and in an assembled condition, in which the first and second lifting arm parts are fitted together, brings additional strength to the structure. The first lifting arm part and the second lifting arm part may abut each other in pre-defined areas.

[0019] In one embodiment, the first lifting arm part and the second lifting arm part each comprises a bent edge along its respective periphery and forms half a shell element which together form a closed shell element with a hollow interior. This has the potential advantage of providing a lighter lifting device while saving material. Sufficient strength is retained in each lifting arm part by a bent edge spanning the entire circumference of the lifting arm part. The first lifting arm part may comprise at least one opening configured for receiving a collar comprised in the second lifting arm part, wherein the opening and collar are configured for providing means for fixing the first lifting arm part and second lifting arm part together.

[0020] In another embodiment, each lifting arm part comprises a set of raised shoulder portions at mutually facing sides of the lifting arm parts, and wherein matching shoulder portions of the respective sets form connection points between the lifting arm parts in an assembled condition of the lifting device, said matching shoulder portions of the respective sets being connected with each other by means of clinching.

[0021] The use of pre-defined areas for providing mutual contact between the two lifting arm parts has the potential advantage of providing two lifting arm parts that may be assembled without use of rivets, thereby reducing the total amount of part required for the lifting device and reducing the energy required to manufacture the lifting device. The skilled person will realise that there are several alternative ways to assemble the two lifting arm parts such as by means of an adhesive or by means of welding.

[0022] The provision of matching shoulder portions that are connected by clinching has the advantage that the lifting arm parts may be made from a thin material, typically around 1 mm, while providing strength and resistance to bending and torsional forces corresponding to an element of a significantly thicker material. Thereby, improved sustainability is obtained since less material is used.

[0023] In a further embodiment, in which each lifting arm comprises a first bearing aperture for the connection to the push arm, and a second bearing aperture for the connection to the secondary frame, well-defined positions for the connection points is made possible.

[0024] In an advantageous further development of this embodiment, each of the first bearing apertures and the second bearing apertures comprises a bearing flange of a pre-defined height. Such a flange may for instance be provided by deep-drawing the material of the lifting arm part itself and provides for an increased bearing surface at the joint with the other components.

[0025] The first and second bearing apertures may furthermore be utilised in the process of connecting the lifting arm parts to each other by aligning respective first bearing apertures and second bearing apertures with each other and performing the clinching of said matching shoulder portions. By fixating the positions of the bearing apertures, any slight relative movement of matching shoulder portions during clinching does not affect the position of the bearing apertures.

[0026] The alignment and ensuing accuracy of the bearing apertures is improved even further in an embodiment, in which the pre-defined height of the bearing flange of each of the first bearing apertures and the second bearing apertures is such that a gap is formed between the mutually facing bearing flanges of the lifting arm parts.

[0027] In one presently preferred embodiment, the lifting device further comprises an adjustment system. The adjustment system may be configured for adjusting the position of a connection point between an arm comprised in the set arms and one of another arm of the set arms, the secondary frame, the sledge, or the sledge guide. By providing a lifting device for which the position of a connection point can be adjusted, the roof window can be configured to be balanced for a range of roof inclinations. It is noted that the roof inclination is measured in relation to a horizontal plane. The adjustment system may be configured to provide a balanced roof window for roof inclinations in the range of 10 to 65 degrees by adjustment of the adjustment system. The adjustment system is particularly well suited for providing a balanced roof window for roof inclinations in the range of 15 to 60 degrees by adjustment of the adjustment system, such as a roof inclination of 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 degrees. It is conceivable that a balanced roof window for a roof inclination lower than 10 degrees and / or higher than 65 degrees can be achieved by changing a component of the spring assembly e.g. by changing the spring to a spring with a different spring constant.

[0028] In embodiments, in which the lifting device comprises an adjustment system, the adjustment system of the lifting device may comprise a worm gear comprising a threaded worm and a worm wheel configured to rotate around perpendicularly extending axes by arranging the threading of the threaded worm between cogs of the worm wheel. The worm gear has the potential advantage of providing a lifting device that can be adjusted from a side of the lifting device from which the user does not have to place themselves or their tools directly between the side frame member of the primary frame holding the spring assembly and the side sash member being held open by the lifting device, thereby providing a lifting device that is safer to operate. Additionally, the worm gear has the potential advantage of reducing the size of the lifting device by allowing a user to operate the adjustment system from the side rather than e.g. from between two parts of the lifting device. The worm gear may be configured to be operated by means of a tool engaging with the threaded worm along the width direction and providing an adjustment of the adjustment system in a direction perpendicular to the width direction. The tool may be any suitable tool fitting the selected drive of the worm gear which may for instance be a hex socket screw drive fitting an Allen key as the tool, or a hexalobular socket screw drive fitting a star drive screw bit for insertion into a screwdriver or a power tool.

[0029] In a further development of embodiments having first and second apertures, the second aperture in the lifting arm is advantageously provided in a punched portion in each lifting arm part, the punched portion being recessed from the mutually facing sides of the lifting arm parts. In this way, compactness, strength and optimum utilisation of material is improved even further.

[0030] In a still further embodiment in which the lifting device comprises an adjustment system, the adjustment screw is provided with such dimensions that the adjustment screw is completely accommodated within the first aperture of the lifting arm. This feature has proven to improve the compactness even further.

[0031] Other presently preferred embodiments and further advantages will be apparent from the subsequent detailed description and drawings.Brief Description of Drawings

[0032] In the following description, embodiments of the invention will be described with reference to the drawings, in which Fig. 1 is a perspective view of a roof window; Fig. 2A is a partial perspective side view of a lifting device of a roof window in an embodiment of the invention, in an open position; Fig. 2B is a partial perspective side view of a lifting device of a roof window in another embodiment of the invention, in an open position; Fig. 3 is a partial side view of the lifting device of Fig. 2; Fig. 4 is a perspective view of the lifting device of Figs. 2 and 3 in an open position; Fig. 5A is close-up view of a part of Fig. 4; Fig. 5B shows the area from Fig. 5A of an alternative embodiment of a lifting device of a roof window according to the invention; Fig. 5C shows the area from Fig. 5C of yet another alternative embodiment of a lifting device of a roof window according to the invention: Fig. 6 is perspective view of an adjustment system of a lifting device of a roof window in an embodiment of the invention; Fig. 7 is a perspective view of a lifting arm of a lifting device of a roof window in an embodiment of the invention; Fig. 8 is an end view of a lifting device of a roof window in an embodiment of the invention; Fig. 9 is a partial perspective view of a lifting device of a roof window in a further embodiment of the invention, in a closed position; Fig. 10 is a perspective view of details of the lifting device of Fig. 9; Fig. 11 is a perspective view of some of the details shown in Fig. 10; Fig. 12 is a partial perspective view of some of the details shown in Figs. 10 and 11; Fig. 13 is an exploded perspective view of some of details of the lifting device of Fig. 9; and Fig. 14 is a bottom view of the details of Fig. 13. Description of Embodiments

[0033] In the following detailed description, a preferred embodiment of the present invention will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. It may also be noted that, for the sake of clarity, the dimensions of certain components illustrated in the drawings may differ from the corresponding dimensions in real-life implementations.

[0034] It is noted that terms such as "up", "down", "left-hand", "right-hand", "exterior", "interior", "outer", "inner" are relative and refers to the viewpoint in question. In general, when referred to an exterior side, this relates to a side of a roof window in the mounted condition facing the outdoors or external side of the building. Conversely, an interior side refers to a side facing the internal side of the building, i.e. typically a subjacent room including any light shaft. Terms such as "outwards" and "inwards" are directions generally perpendicular to an interior-exterior direction, taking as its base point a centre of the roof window. A longitudinal direction is, if nothing else is mentioned, longitudinal along the length of a frame member of the roof window. It is to be understood that the arrangement shown in a horizontal orientation is not the normal orientation as the roof window is installed in an inclined roof.General description of roof window

[0035] In the following, details relating to a general embodiment of a roof window 100 such as the one shown in Fig. 1 will be described. The roof window 100 is intended to be installed in or on an inclined roof surface (not shown).

[0036] The roof window 100 comprises a primary frame 1 and at least one secondary frame which is moveable relative to the primary frame 1. The primary frame 1 is configured to be mounted to a roof structure (not shown) defining the inclined roof surface and is stationary once mounted. In the embodiment shown in Fig. 1, two secondary frames are provided, namely an intermediate frame 3 and a sash 2 carrying a glazing element in the form of a pane 4. However, embodiments are conceivable in which only a single secondary frame is present, such as for instance a pane-carrying sash.

[0037] The primary frame 1 comprises a set of frame members including in this embodiment a top frame member, two side frame members and a bottom frame member. Correspondingly, the sash 2 comprises a set of sash members including a top sash member, two side sash members and a bottom sash member. While the primary frame 1 and sash 2 are described as rectangular structures, some principles of the presented concepts may be applicable to other geometrical shapes as well.

[0038] In the embodiment shown, the intermediate frame 3 comprises two arms extending from the top frame member and to a position approximately at the longitudinal centre of the respective side sash member. Embodiments are conceivable in which the intermediate frame forms a coherent U-shape including arms and a cross-bar, or is substantially rectangular, i.e. including four frame members as the primary frame 1 and sash 2.

[0039] The sash 2 of the roof window 100 is openable relative to the primary frame 1 to obtain one or more open positions. In such open position(s), the sash 2 and pane 4 are moved out of the plane of the roof window 100 defined by the primary frame 1. The roof window 100 is operated using an operating assembly, here including a handle 5 at the bottom sash member configured to interact with a locking device or striking plate at the bottom frame member. Additional or alternative operating assemblies are conceivable.

[0040] The sash 2 of the roof window 100 is top-hung in at least a first operational condition which may correspond to a normal use. That is, in this first operational condition, the sash 2 is rotated about a substantially horizontal axis of rotation A at or near the top frame member and top sash member, by means of a hinge assembly comprising a top bearing 60 connecting the primary frame 1 with the secondary frame(s). In the embodiment shown in Fig. 1, the top bearing 60 connects the intermediate frame 3 to the primary frame 1, and the sash 2 is rotatable about the axis of rotation A at the top bearing 60 via the intermediate frame 3. Thus, the sash 2 is rotated about the substantially horizontal first axis of rotation A at or near the top frame member and top sash member between a closed position and an open position. The hinge assembly including the top bearing 60 will be discussed in greater details below.

[0041] In the embodiment shown, the sash 2 is able to rotate through approximately 180° in a second operational condition, about a second horizontal axis of rotation B here positioned approximately half-way between the top and bottom of the roof window 100. This offers the possibility of utilising the roof window 100 as a pivoting roof window but also provides for easy access to the exterior surface of the pane 4 from the interior of the building in which the roof window 100 is installed for cleaning of the window. To achieve this second operational condition, the roof window 100 is provided with a set of a pivot hinge fittings of which a sash hinge part 8 and a frame hinge part 9 of opposite side members of the sash 2 and primary frame 1, respectively, are indicated in Fig. 1.

[0042] It is however conceivable to apply some principles of the presented concepts for roof windows on different types of windows having other opening patterns.

[0043] In the following, the sash 2 will represent the secondary frames and reference will be made to the sash 2 only, even if the secondary frame structure may involve the intermediate frame 3 as shown in Fig. 1 as well.

[0044] The side frame members extend in a length direction L, and the top frame member extends in a width direction W perpendicular to the length direction L. A height direction H extends perpendicular to the length direction L and width direction W. References to the length, height, and width in relation to a lifting device 10 is to be understood as in that the lifting device 10 is arranged in the roof window as intended. Thus, the length, height, and width may also be defined according to the lifting device 10, such as the length direction L being defined by the sliding direction of a sledge in a sledge guide of the lifting device 10, as will be apparent throughout the description.

[0045] The roof window 100 is provided with the lifting device 10 to balance at least part of the weight of the movable components of the roof window 100 and facilitate operation of the window.Lifting device

[0046] Referring now also to Figs. 2 to 4, the lifting device 10 is shown from various sides.

[0047] In Figs. 2 to 4 a lifting device is shown in an open position of a roof window for a 45-degree pitch.

[0048] The lifting device shown in Fig. 2B and Figs. 3 and 4 is a modification of the lifting device shown in Fig. 2A in that it also comprises an adjustment system 17, which will be explained in further detail below.

[0049] The lifting device 10 comprises a spring assembly 11 configured to be coupled to a sledge 12. In turn, the sledge 12 is configured to slide in a sledge guide 13. The sledge guide 13 comprises a first rail 13.1 and a second rail 13.2 which are both shown in Fig. 4.

[0050] In Figs. 2 and 3 the first rail 13.1 of the sledge guide 13 is removed to improve the readability of the drawing figures. Each of the rails 13.1, 13.2 comprises flanges configured to retain the sledge 12 in the sledge guide 13. The two rails 13.1, 13.2 together form a track of the sledge guide 13, wherein the sledge 12 is configured to slide in the track of the sledge guide.

[0051] The lifting device 10 furthermore comprises a lifting arm 14, a sledge arm 15, and a push arm 16. The arms form a linkage mechanism enabling suitable management of forces and movement in the lifting device.

[0052] The lifting arm 14 is inserted between the primary frame 1 and the sash 2 and extends between a first end 14.1 and a second end 14.2. The lifting arm 14 is rotatably connected to the sash 2 by its second end 14.2 at a distance from the top bearing 60. The lifting arm 14 is connected to the sledge guide 13 via the push arm 16.

[0053] The push arm 16 is shown with a first end 16.1 rotatably connected to the sledge guide 13 and a second end 16.2 rotatably connected to the lifting arm 14 at a distance from the first end 14.1 of the lifting arm 14.

[0054] The sledge arm 15 comprises a first sledge arm part 15a and a second sledge arm part 15b arranged on the outside of the lifting arm 14. Correspondingly, the push arm 16 comprises two parts located on the outside of the lifting arm 14 of which one push arm part 16a is shown in Fig. 2.

[0055] Even though only a single lifting device 10 for one side of the roof window is shown, it is understood that a similar lifting device may be arranged on the other side of the roof window as well. By having a lifting device 10 installed on each side frame member an even lift of the sash is provided.

[0056] To adjust the roof window 100 to a specific roof inclination for a selected spring assembly 11, the lifting device 10 of the embodiments shown further comprises an adjustment system 17.

[0057] The adjustment system 17 is connected to the sledge 12 and in turn to the spring assembly 11 by means of the sledge arm 15. The sledge arm 15 extends between a first end 15.1 which is rotatably connected to the sledge 12 and a second end 15.2 which is connected to the adjustment system 17.

[0058] The adjustment system 17 is also connected to the lifting arm 14, and the connection between the sledge arm 15 and the lifting arm 14 via the adjustment system 17 will be described in more detail in the following.

[0059] First, the general functionality of the lifting device 10 will be described in some detail. In Figs. 2 to 4, the sledge 12 is coupled to the spring assembly 11 which is arranged to exert a force on the sledge 12 and thereby act as a force balancing element. The sledge 12 may be uncoupled from the spring assembly 11. This may, as an example, be an advantage during installation of the roof window where a spring force acting on the sledge 12 may make it difficult to handle the roof window. In the cases where the lifting device 10 is installed in the roof window according to its intended use, the sledge 12 and the spring assembly 11 are initially in an uncoupled state. The spring assembly 11 and the sledge 12 are then coupled by opening the roof window resulting in the sledge 12 sliding towards a coupling device such as a hook 11.1 attached to the spring assembly 11. Such a coupling may for example be realised by the sledge 12 comprising a hook plate 12.1 inserted into side flanges of the sledge 12 for coupling the sledge 12 to the spring assembly 11. Opening the roof window results in the sledge 12 engaging with the hook 11.1 and once the roof window is subsequently closed, the sledge 12 will slide in a direction away from the spring assembly 11 towards the top bearing 60 of the roof window while the spring assembly 11, now coupled to the sledge 12, will exert a pulling force on the sledge 12 and provide a resistance against the closing of the roof window, thereby biasing the spring assembly 11. The pulling force of the spring assembly 11 and the weight of the roof window are preferably balanced such that the roof window can be positioned in an open position without forcing it to close due to its own weight or forcing it to open further due to the pulling force applied by the spring assembly. This balance is affected by the inclination of the roof that the roof window is installed in.

[0060] The configuration of the spring or springs in the spring assembly 11 may be dependent on a specific roof inclination. If the roof window is installed on a roof with a roof inclination different than the intended inclination, the spring force from the spring assembly 11 acting on the sledge 12 will not balance the weight of the roof window. In one example, the spring assembly 11 may exert too much force on the window thereby forcing the window to open further. In another example, the spring assembly may be too weak, and the window will close due to its own weight. In both cases, the window may be difficult for the user to operate and potentially hazardous.

[0061] To easily adjust the roof window according to roof inclination, the adjustment system 17 is used. The adjustment system 17 can be used to adjust the roof window for roof inclinations in the range of 15 to 60 degrees.

[0062] As previously mentioned, the top sash member and top frame member are connected by a hinge assembly at least in the first operational condition. A top bearing fitting 6 facilitates this connection. The top bearing fitting 6 comprises a frame attachment section 6.1 a guide attachment section 6.2 extending from the frame attachment section 6.1, as best seen in Fig. 5A. The top bearing 60 is connected to the frame attachment section 6.1. The guide attachment section 6.2 comprises means for attaching the top bearing fitting 6 to the sledge guide 13. The sledge guide 13 is securely fixed to the side frame member the top bearing fitting 6 facilitates the connection between the sash and the frame via the sledge guide 13.

[0063] In Figs. 2 to 5A the top bearing fitting 6 is arranged between the first rail 13.1 and second rail 13.2 of the sledge guide 13. The top bearing 6 is also fixed to both rails 13.1, 13.2, which provides an even load transfer from the spring assembly 11 to the top bearing 6 through the sledge guide 13. However, the lifting device 10 is configured for a selection of different top bearing fittings 6 that serves different purposes, thereby allowing the lifting device 10 to be installed in different types of windows. Fig. 5B shows an alternative top bearing fitting 6' which is only attached to the second rail 13.2. This top bearing fitting can e.g. be used for retrofitting other window models with a lifting device according to this disclosure. Fig. 5C shows the lifting device 10 from Fig. 5A modified with yet another alternative top bearing fitting 6", where the top bearing fitting 6" comprises a hook element 6.3 providing additional attachment to the primary frame 1. This top bearing fitting 6" can e.g. be used when the roof window is installed with a heavy sash such as a 3-layered pane carrying sash. A top bearing fitting that is attached only to the first rail 13.1 may also be envisioned.Adjustment system with worm gear

[0064] In the embodiments shown in Figs. 2 to 4, the adjustment system 17 is configured to adjust the roof window 100 to a specific roof inclination by changing the relative position of a connection point between the lifting arm 14 and the sledge arm 15.

[0065] In the embodiments shown, the connection point is a bushing 17.1. In this context, a connection point is defined as a pivot point between two elements such as between the lifting arm and the push arm, which during normal operation of the roof window i.e. during opening and closing of the window, is configured to perform only a rotating movement. The adjustment system is configured to perform a translational movement of the connection point during adjustment of the adjustment system. In principle, the adjustment system may be configured to perform a translational movement of any one or more connection points between any one of the sledge 12, sledge arm 15, lifting arm 14, sash 2, or push arm 16.

[0066] The adjustment system 17 comprises an adjustment screw 17.2 with a threaded screw shaft 17.3, a worm wheel 17.4, and a screw top 17.5, as best shown in Fig. 6. The adjustment system 17 further comprises a threaded worm 17.6 coupled to the adjustment worm wheel 17.4. The threaded worm 17.6 and the worm wheel 17.4 form a worm gear configured to allow adjustment of the adjustment system 17 from a side of the lifting device from which the user does not have to place themselves or their tools directly between the side frame member of the primary frame holding the spring assembly and the side sash member being held open by the lifting device i.e. by inserting a tool in the threaded worm 17.6 from a direction parallel to the width direction W, as indicated by an arrow T in Fig. 5A, said tool being configured for rotating the threaded worm 17.6 around an axis extending in the width direction w, thereby rotating the worm wheel 17.4 and the threaded screw shaft 17.3 around an axis perpendicular to the width direction as indicated by arrow RW resulting in a translational movement of the bushing 17.1 by the rotation of the threaded screw shaft 17.3, as indicated by arrows TC and RS, respectively, in Fig. 6. The tool may be any suitable tool fitting the selected drive of the worm gear which may for instance be a hex socket screw drive fitting an Allen key as the tool, or a hexalobular socket screw drive fitting a star drive screw bit for insertion into a screwdriver or a power tool.

[0067] The first end 15.1 of the sledge arm 15 is coupled to the bushing 17.1 and the second end 15.2 of the sledge arm 15 is rotatably connected to the sledge 12. The adjustment system 17 is adjusted by rotating the adjustment screw 17.2 such that the bushing 17.1 moves along the length of the threaded screw shaft 17.3 thereby changing the position of the bushing 17.1 and thereby the connection point between the lifting arm 14 and sledge arm 15. This change in position shifts the weight distribution of the lifting device making it possible to adjust the force balance according to the roof inclination.

[0068] The lifting arm 14 comprises a first aperture 14.31 in proximity to its first end 14.1 to accommodate the adjustment screw 17.2. This aperture 14.31 is rectangular-shaped in this embodiment. The worm wheel 17.4 and the threaded worm 17.6 are accommodated in a separate, second aperture 14.32, shown in Fig. 7) in the lifting arm 14. In the embodiment shown, the adjustment screw 17.2 is accommodated within the lifting arm 14 at the screw top 17.5.Structure of components

[0069] As indicated in Figs. 2 to 4, the lifting arm 14 comprises two lifting arm parts 14a and 14b. The lifting arm parts 14a, 14b are fitted together to move as a single lifting arm 14. In the embodiment shown, the lifting arm parts 14a, 14b are formed from metal plates with a thickness of 1.5 mm. As best shown in Fig. 7, the lifting arm part 14a comprises a plurality of openings 14.4 each configured for receiving a collar 14.5 from lifting arm part 14b. The lifting arm part 14b and collars 14.5 are uniformly formed from the same metal plate. Each collar has a collar height larger than the thickness of the lifting arm part 14a. To secure the lifting arm parts to each other, each collar 14.5 is inserted in the corresponding collar receiving opening 14.4 until a part of the collar 14.5 extends from the collar receiving opening on the opposite side from which it was inserted. The extending parts of the collars are deformed in a manner that restricts the collars from being retracted from the openings. The lifting arm parts 14a, 14b are thereby fitted together without the use of rivets and the combined surface area of contact between the two lifting arm parts is increased, which reduces wear and tear on the respective parts.

[0070] The shape of the lifting arm parts 14a, 14b and the position and form of the openings 14.4 have been carefully selected to optimize strength properties and reduce material consumption. The lifting arm parts 14a, 14b abut each other in pre-defined areas.

[0071] In the embodiment of Figs. 2 to 4 and as shown in Fig. 7 each lifting arm part comprises a bent edge 14.6 along its respective periphery and forms half a shell element which together form a closed shell element with a hollow interior. Sufficient strength is retained in each lifting arm part by the bent edge 14.6 spanning the entire circumference of the lifting arm part while reducing the total weight and material consumption of the lifting device. The pre-defined areas are here constituted by the areas in which the collars 14.5 interacts with the counterpart collar receiving openings 14.4, and of the area of the bent edges 14.6.

[0072] Turning now again to Fig. 4, the lifting device 10 of Figs. 1 - 3 is shown from a different angle with both rails 13.1, 13.2 of the sledge guide 13 being visible. The frame 1 is indicated as a dashed box representing the side frame member to which the lifting device 10 is fastened.

[0073] The first rail 13.1 extends substantially the entire length in a length direction L of the side frame member to which the lifting device is attached. The first rail 13.1 is formed from a metal plate having a thickness of 1 mm. The first rail 13.1 is firmly fixed directly to the side frame member and forms part of a side frame reinforcement element. The first rail 13.1 forming part of the sledge guide 13 and part of the side frame reinforcement serves at least three purposes. Firstly, by having the first rail 13.1 as a side frame reinforcement element, a separate frame reinforcement element can be dispensed with compared to the wooden roof windows in production today which have a separate metal reinforcement plate situated at the exterior frame side, thereby reducing the material consumption of the roof window. Secondly, the first rail 13.1 can be arranged closer to the side frame member of the primary frame compared to windows with a separate reinforcement element arranged between the lifting device and the side frame member, thereby reducing the torque on said side frame member. Thirdly, the combined width of the lifting device and side frame reinforcement in the width direction W is reduced making the side sash frame less bulky.

[0074] The second rail 13.2 is here substantially shorter than first rail 13.1 and extends the travelling length of the sledge when the window moves from a closed configuration to a completely open configuration. The second rail 13.2 is formed from a metal plate having a thickness of 1 mm, but other dimensions are conceivable.

[0075] The width of the lifting device 10 in the width direction W from the first rail 13.1 to the second rail 13.2 is substantially 30 mm.

[0076] Turning now to Fig. 8, the lifting device 10 from Figs. 2 - 4 is shown from an end of the lifting device 10 looking in the length direction L along the rails 13.1, 13.2 of the sledge guide 13. The top bearing fitting 6 is arranged at a distance from the first rail 13.1 and second rail 13.2 by means of spacers 18. The top bearing fitting 6 is arranged between the first rail 13.1 and second rail 13.2 and is arranged closest to the second rail 13.2. The top bearing fitting 6 is arranged in a plane P defined by the height direction H and length direction L. Correspondingly, the set of arms and sledge are arranged symmetrically with respect to the plane P. By arranging the set of arms, top bearing fitting 6 and sledge 12 closest to the second rail 13.2, there is sufficient space for installing two roof windows as indicated by a spring assembly 11' of a neighbouring window, each roof window having a lifting device 10 according to the disclosure, next to each other, while still having room for roof cover elements covering the sash and frame elements.

[0077] Referring now to Figs. 9 to 14, a further embodiment of a lifting device of a roof window of the invention will be described. Reference numerals having the same or analogous function as in the above-described embodiments carry the same reference numerals. Only differences to the above-described embodiments will be described in detail.

[0078] As in the above-described embodiment Figs. 2 to 4 and 7, the lifting arm 14 comprises two lifting arm parts 14a and 14b. The lifting arm parts 14a, 14b are fitted together in an assembled condition of the lifting device to move as a single lifting arm 14.

[0079] The lifting arm parts 14a, 14b are made from a plate-shaped material such as metal. However, as will be described in further detail below, the connection between the lifting arm parts 14a, 14b makes it possible to reduce the thickness of the plate-shaped material and the thickness of each lifting arm part 14a, 14b is about 1 mm.

[0080] Different from the above embodiment shown, the lifting arm parts 14a, 14b, each lifting arm part 14a, 14b comprises a set of raised shoulder portions 14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b at mutually facing sides of the lifting arm parts 14a, 14b. During assembly of the lifting arm 14 matching shoulder portions 14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b of the respective sets are brought together to form connection points between the lifting arm parts 14a, 14b.

[0081] In the embodiment shown, the matching shoulder portions 14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b of the respective sets are connected with each other by means of clinching. This may be performed in many ways, for instance by TOX ®< technology.

[0082] In the shown embodiment in which each lifting arm part 14a, 14b comprises a first bearing aperture 14a.16, 14b.16 for the connection to the push arm 16, and a second bearing aperture 14a.2, 14b.2 for the connection to the secondary frame 2, each of the first bearing apertures 14a.16, 14b.16 and the second bearing apertures 14a.2, 14b.2 comprises a bearing flange of a pre-defined height.

[0083] During assembly, the lifting arm parts 14a, 14b are connected to each other by aligning respective first bearing apertures 14a.16, 14b.16 and second bearing apertures 14a.2, 14b.2. This may be carried out by placing the lifting arm parts 14a, 14b on a template with two pins such that the first bearing apertures 14a.16, 14b.16 are aligned with each other and the second bearing apertures 14a.2, 14b.2 are aligned with each other. Subsequently, the clinching of the matching shoulder portions 14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b is performed. Since only the position of the first bearing apertures 14a.16, 14b.16 and second bearing apertures 14a.2, 14b.2 is important to the functionality of the lifting arm 14 in the assembled condition of the lifting device 10, any slight relative movement of matching shoulder portions during clinching does not affect the position of the bearing apertures.

[0084] This is ensured to an even larger extent by the feature, seen most clearly in Fig. 14, that the pre-defined height of the bearing flange of each of the first bearing apertures 14a.16, 14b.16 and the second bearing apertures 14a.2, 14b.2 is such that a gap is formed between the mutually facing bearing flanges of the lifting arm parts 14a, 14b.

[0085] A further feature of the present embodiment is shown most clearly in Figs. 12 and 13, namely that the second aperture 14.32 in the lifting arm 14, configured to receive the worm wheel 17.4 and the threaded worm 17.6, is provided in a punched portion 14.8a, 14.8b in each lifting arm part 14a, 14b in such a way that the punched portion 14.8a, 14.8b is recessed from the mutually facing sides of the lifting arm parts 14a, 14b. In this way, a hollow is formed by the mutually facing concave sides of the punched portions 14.8a, 14.8b.

[0086] Finally, the overall dimensions of the lifting device 10 are minimised by careful selection of the components involved. In the embodiment shown, the adjustment screw 17.2 is provided with such dimensions that the adjustment screw 17.2 is completely accommodated within the first aperture 14.31 of the lifting arm 14. In this way, the only parts of the adjustment device 17 protruding from the contour of the lifting arm 14 are the worm wheel 17.4 and the threaded worm 17.6 as illustrated in Fig. 11.List of reference numerals

[0087] 1 primary frame 2 secondary frame / sash 3 secondary frame / intermediate frame 4 pane 5 operating assembly / handle 6, 6', 6" top bearing fitting 6.1 frame attachment section 6.2 guide attachment section 8 sash hinge part 9 frame hinge part 10 lifting device 11, 11' spring assembly 11.1 hook 12 sledge 12.1 hook plate 13 sledge guide 13.1 first rail of sledge guide 13.2 second rail of sledge guide 14 lifting arm 14a first lifting arm part 14a.2 second bearing aperture (for secondary frame joint) 14a.16 first bearing aperture (for push arm joint) 14b second lifting arm part 14b.2 second bearing aperture (for secondary frame joint) 14b.16 first bearing aperture (for push arm joint) 14.1 first end of lifting arm 14.2 second end of lifting arm 14.2a 14.2b 14.31 first aperture (for adjustment screw) 14.32 second aperture (for worm wheel and threaded worm) 14.4 openings for collars 14.5 collar 14.6 bent edge 14.70a protrusion 14.70b protrusion 14.71a shoulder portion 14.71b shoulder portion 14.72a shoulder portion 14.72b shoulder portion 14.73a shoulder portion 14.73b shoulder portion 14.8a punched portion 14.8b punched portion 15 sledge arm 15a first sledge arm part 15ab second sledge arm part 15.1 first end of sledge arm 15.2 second end of sledge arm 16 push arm 16a first push arm part 16.1 first end of push arm 16.2 second end of push arm 17 adjustment system 17.1 bushing 17.2 adjustment screw 17.3 threaded screw shaft 17.4 worm wheel 17.5 screw top 17.6 threaded worm 18 spacer 60 top bearing 100 roof window A first axis of rotation B second axis of rotation L length direction W width direction H height direction P plane TT arrow for insertion of tool RW arrow for rotation of worm RS arrow for rotation of threaded screw shaft TC arrow for translation of bushing

Examples

Embodiment Construction

[0033]In the following detailed description, a preferred embodiment of the present invention will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. It may also be noted that, for the sake of clarity, the dimensions of certain components illustrated in the drawings may differ from the corresponding dimensions in real-life implementations.

[0034]It is noted that terms such as "up", "down", "left-hand", "right-hand", "exterior", "interior", "outer", "inner" are relative and refers to the viewpoint in question. In general, when referred to an exterior side, this relates to a side of a roof window in the mounted condition facing the outdoors or external side of the building. Conversely, an interior side refers to a side facing the internal side of the building, i.e. typically a subjacent room including any light shaft. Terms...

Technical Field

[0001] The present invention relates to a roof window, particularly for installation in or on a roof surface having an inclination, comprising a primary frame comprising a top frame member, two side frame members, and a bottom frame member, at least one secondary frame, a lifting device comprising a sledge, a sledge guide, a set of arms, and a spring assembly, wherein the spring assembly is configured to be coupled to the sledge, and the sledge guide comprises a first rail and a second rail.Background Art

[0002] Windows for installation in an inclined roof surface may be provided in a number of varieties and include more or less complicated operational structures to allow opening of the sash and to fulfil other functions, such as ventilation. Such roof windows include the type hinged at or near the middle (generally designated "pivoting roof windows"), the top-hinged type, and finally the roof windows that are top-hinged during normal operation but in which the sash is able to perform a rotating movement substantially at a centre axis near the middle of the sash, either for cleaning of the outside of the pane mounted in the sash or for providing an alternative manner of operation. Roof windows of the top-hinged type have a first axis of rotation provided by a top hinge arrangement to provide a first operational condition, whereas rotation of the sash in a second operational condition is performed by means of an intermediate frame in which the sash is hinged to provide a secondary axis of rotation. Typically, one hinge of the hinge arrangement will be located at either side of the roof window to define a substantially horizontal axis of rotation.

[0003] Examples of top-hinged windows with a second operational condition are for instance disclosed in Applicant's WO-A-89 / 10460, EP 0 733 126 B1, EP 1 873 323 B1, EP 2 762 665 A2, and WO 2019101281 A1. To make it possible to rotate the window sash approximately 180° to a convenient cleaning position of the pane, the sash structure is connected with an intermediate frame with frame arms, which in the closed position of the window are positioned between the upper parts of the frame and sash side members, and which during normal use of the window as a top-hung window follow the sash side members.

[0004] Furthermore, the opening of a roof window and the force required to operate the window is majorly affected by the inclination of the roof, where the window is installed.

[0005] In roof windows in which the operation takes place either entirely or partially about an axis of rotation at the top, it is known to balance at least part of the weight of the movable components by means of a lifting device which includes a spring to generate the forces needed to balance the weight of the pane carrying sash. The purpose of this arrangement is to facilitate opening of the window, and the dimensions may be chosen so that the spring can retain the top-hinged sash in equilibrium in a desired opening position.

[0006] Such a lifting device is for instance disclosed in the Applicant's WO 2019 / 101281 A1 where a spring assembly acts as a force balancing element to the pane-carrying frame by operating on a lifting arm attached to the frame.

[0007] However, although the lifting device in the above example is to some extent capable of providing the desired force balance, there is still room for improvement.Summary of Invention

[0008] With this background it is an object of the present invention to provide the roof window with an increased design flexibility including a lifting device with the desired movement pattern and simple structure with reduced material consumption.

[0009] This is achieved with a roof window of the kind mentioned in the introduction, which is further characterised in that at least one of the first rail and the second rail forms part of a side frame reinforcement element attached to one of the side frame members.

[0010] A lifting device wherein at least one of the first rail and the second rail forms part of a side frame reinforcement element attached to one of the side frame members has the potential advantages that a separate reinforcement element can be dispensed with, that the total size of the lifting device is reduced while retaining function, and in that the sledge guide is arranged closer to the side frame member which reduces the torque from the spring assembly acting on the frame members.

[0011] Even though reference is made to the first rail forming part of the side frame member the skilled person realizes that it equally corresponds to embodiments wherein the second rail forms the side frame reinforcement.

[0012] The first rail may extend substantially the entire length of the side frame member. By having a first rail that extends substantially the entire length of the side frame member the first rail reinforces the side frame member in substantially its entire length thereby optimizing the reinforcing capabilities of the first side rail. A majority of the rail is not directly configured to act as a sledge guide. The first rail extending the substantially entire length of the side frame may additionally be configured to partially house the spring assembly. This has the potential advantage that the first rail has multiple functionalities i.e. the first rail functions as part of a sledge guide, a reinforcing element and a spring housing, thereby saving both material and parts in the lifting device, while having the further potential advantage of providing a simpler lifting device which is easier and quicker to assemble and install.

[0013] The set of arms may be arranged in many different ways to translate a pull from the spring assembly to an opening of the secondary frame. In one embodiment, the set of arms comprises a lifting arm, a push arm, and a sledge arm. The sledge arm may be attached to the sledge at one connection point and to the lifting arm at another connection point. The push arm may be attached to the sledge guide at yet another connection point and to the lifting arm at yet another connection point. The lifting arm may additionally be attached to the secondary frame at yet another connection point.

[0014] A connection point is in principle defined as a pivot point between any two elements such as between the lifting arm and the push arm, which during normal operation of the roof window i.e. during opening and closing of the window, is configured to perform only a rotating movement.

[0015] The inventors have found that a set of arms comprising a lifting arm, a push arm, and a sledge arm, wherein the sledge arm is attached to the sledge at a connection point and to the lifting arm at another connection point, wherein the push arm is attached to the sledge guide at yet another connection point and to the lifting arm at yet another connection point, and wherein the lifting arm is additionally attached to the secondary frame at yet another connection point provides a balanced lifting device with the desired movement pattern. When a user opens the inclined roof window the lifting device counteracts i.e. balances the gravitational pull that urges the window towards a closed position such that the roof window can maintain a specific opening degree. The inventors have found that the set of arms as described provides a balanced roof window for up to 50 degrees opening relative to a closed configuration of the roof window and particularly suited for opening degrees up to 45 degrees opening.

[0016] "Balanced" is generally to be understood as in that the lifting device provides a pulling force that balances the gravitational pull that urges the open window towards the closed configuration.

[0017] The sledge guide may be attached to the primary frame and the sledge may be slidably connected to the primary frame via the sledge guide.

[0018] The lifting arm may comprise a first lifting arm part and a second lifting arm part. This configuration has several advantages from a manufacturing point of view, and in an assembled condition, in which the first and second lifting arm parts are fitted together, brings additional strength to the structure. The first lifting arm part and the second lifting arm part may abut each other in pre-defined areas.

[0019] In one embodiment, the first lifting arm part and the second lifting arm part each comprises a bent edge along its respective periphery and forms half a shell element which together form a closed shell element with a hollow interior. This has the potential advantage of providing a lighter lifting device while saving material. Sufficient strength is retained in each lifting arm part by a bent edge spanning the entire circumference of the lifting arm part. The first lifting arm part may comprise at least one opening configured for receiving a collar comprised in the second lifting arm part, wherein the opening and collar are configured for providing means for fixing the first lifting arm part and second lifting arm part together.

[0020] In another embodiment, each lifting arm part comprises a set of raised shoulder portions at mutually facing sides of the lifting arm parts, and wherein matching shoulder portions of the respective sets form connection points between the lifting arm parts in an assembled condition of the lifting device, said matching shoulder portions of the respective sets being connected with each other by means of clinching.

[0021] The use of pre-defined areas for providing mutual contact between the two lifting arm parts has the potential advantage of providing two lifting arm parts that may be assembled without use of rivets, thereby reducing the total amount of part required for the lifting device and reducing the energy required to manufacture the lifting device. The skilled person will realise that there are several alternative ways to assemble the two lifting arm parts such as by means of an adhesive or by means of welding.

[0022] The provision of matching shoulder portions that are connected by clinching has the advantage that the lifting arm parts may be made from a thin material, typically around 1 mm, while providing strength and resistance to bending and torsional forces corresponding to an element of a significantly thicker material. Thereby, improved sustainability is obtained since less material is used.

[0023] In a further embodiment, in which each lifting arm comprises a first bearing aperture for the connection to the push arm, and a second bearing aperture for the connection to the secondary frame, well-defined positions for the connection points is made possible.

[0024] In an advantageous further development of this embodiment, each of the first bearing apertures and the second bearing apertures comprises a bearing flange of a pre-defined height. Such a flange may for instance be provided by deep-drawing the material of the lifting arm part itself and provides for an increased bearing surface at the joint with the other components.

[0025] The first and second bearing apertures may furthermore be utilised in the process of connecting the lifting arm parts to each other by aligning respective first bearing apertures and second bearing apertures with each other and performing the clinching of said matching shoulder portions. By fixating the positions of the bearing apertures, any slight relative movement of matching shoulder portions during clinching does not affect the position of the bearing apertures.

[0026] The alignment and ensuing accuracy of the bearing apertures is improved even further in an embodiment, in which the pre-defined height of the bearing flange of each of the first bearing apertures and the second bearing apertures is such that a gap is formed between the mutually facing bearing flanges of the lifting arm parts.

[0027] In one presently preferred embodiment, the lifting device further comprises an adjustment system. The adjustment system may be configured for adjusting the position of a connection point between an arm comprised in the set arms and one of another arm of the set arms, the secondary frame, the sledge, or the sledge guide. By providing a lifting device for which the position of a connection point can be adjusted, the roof window can be configured to be balanced for a range of roof inclinations. It is noted that the roof inclination is measured in relation to a horizontal plane. The adjustment system may be configured to provide a balanced roof window for roof inclinations in the range of 10 to 65 degrees by adjustment of the adjustment system. The adjustment system is particularly well suited for providing a balanced roof window for roof inclinations in the range of 15 to 60 degrees by adjustment of the adjustment system, such as a roof inclination of 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 degrees. It is conceivable that a balanced roof window for a roof inclination lower than 10 degrees and / or higher than 65 degrees can be achieved by changing a component of the spring assembly e.g. by changing the spring to a spring with a different spring constant.

[0028] In embodiments, in which the lifting device comprises an adjustment system, the adjustment system of the lifting device may comprise a worm gear comprising a threaded worm and a worm wheel configured to rotate around perpendicularly extending axes by arranging the threading of the threaded worm between cogs of the worm wheel. The worm gear has the potential advantage of providing a lifting device that can be adjusted from a side of the lifting device from which the user does not have to place themselves or their tools directly between the side frame member of the primary frame holding the spring assembly and the side sash member being held open by the lifting device, thereby providing a lifting device that is safer to operate. Additionally, the worm gear has the potential advantage of reducing the size of the lifting device by allowing a user to operate the adjustment system from the side rather than e.g. from between two parts of the lifting device. The worm gear may be configured to be operated by means of a tool engaging with the threaded worm along the width direction and providing an adjustment of the adjustment system in a direction perpendicular to the width direction. The tool may be any suitable tool fitting the selected drive of the worm gear which may for instance be a hex socket screw drive fitting an Allen key as the tool, or a hexalobular socket screw drive fitting a star drive screw bit for insertion into a screwdriver or a power tool.

[0029] In a further development of embodiments having first and second apertures, the second aperture in the lifting arm is advantageously provided in a punched portion in each lifting arm part, the punched portion being recessed from the mutually facing sides of the lifting arm parts. In this way, compactness, strength and optimum utilisation of material is improved even further.

[0030] In a still further embodiment in which the lifting device comprises an adjustment system, the adjustment screw is provided with such dimensions that the adjustment screw is completely accommodated within the first aperture of the lifting arm. This feature has proven to improve the compactness even further.

[0031] Other presently preferred embodiments and further advantages will be apparent from the subsequent detailed description and drawings.Brief Description of Drawings

[0032] In the following description, embodiments of the invention will be described with reference to the drawings, in which Fig. 1 is a perspective view of a roof window; Fig. 2A is a partial perspective side view of a lifting device of a roof window in an embodiment of the invention, in an open position; Fig. 2B is a partial perspective side view of a lifting device of a roof window in another embodiment of the invention, in an open position; Fig. 3 is a partial side view of the lifting device of Fig. 2; Fig. 4 is a perspective view of the lifting device of Figs. 2 and 3 in an open position; Fig. 5A is close-up view of a part of Fig. 4; Fig. 5B shows the area from Fig. 5A of an alternative embodiment of a lifting device of a roof window according to the invention; Fig. 5C shows the area from Fig. 5C of yet another alternative embodiment of a lifting device of a roof window according to the invention: Fig. 6 is perspective view of an adjustment system of a lifting device of a roof window in an embodiment of the invention; Fig. 7 is a perspective view of a lifting arm of a lifting device of a roof window in an embodiment of the invention; Fig. 8 is an end view of a lifting device of a roof window in an embodiment of the invention; Fig. 9 is a partial perspective view of a lifting device of a roof window in a further embodiment of the invention, in a closed position; Fig. 10 is a perspective view of details of the lifting device of Fig. 9; Fig. 11 is a perspective view of some of the details shown in Fig. 10; Fig. 12 is a partial perspective view of some of the details shown in Figs. 10 and 11; Fig. 13 is an exploded perspective view of some of details of the lifting device of Fig. 9; and Fig. 14 is a bottom view of the details of Fig. 13. Description of Embodiments

[0033] In the following detailed description, a preferred embodiment of the present invention will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. It may also be noted that, for the sake of clarity, the dimensions of certain components illustrated in the drawings may differ from the corresponding dimensions in real-life implementations.

[0034] It is noted that terms such as "up", "down", "left-hand", "right-hand", "exterior", "interior", "outer", "inner" are relative and refers to the viewpoint in question. In general, when referred to an exterior side, this relates to a side of a roof window in the mounted condition facing the outdoors or external side of the building. Conversely, an interior side refers to a side facing the internal side of the building, i.e. typically a subjacent room including any light shaft. Terms such as "outwards" and "inwards" are directions generally perpendicular to an interior-exterior direction, taking as its base point a centre of the roof window. A longitudinal direction is, if nothing else is mentioned, longitudinal along the length of a frame member of the roof window. It is to be understood that the arrangement shown in a horizontal orientation is not the normal orientation as the roof window is installed in an inclined roof.General description of roof window

[0035] In the following, details relating to a general embodiment of a roof window 100 such as the one shown in Fig. 1 will be described. The roof window 100 is intended to be installed in or on an inclined roof surface (not shown).

[0036] The roof window 100 comprises a primary frame 1 and at least one secondary frame which is moveable relative to the primary frame 1. The primary frame 1 is configured to be mounted to a roof structure (not shown) defining the inclined roof surface and is stationary once mounted. In the embodiment shown in Fig. 1, two secondary frames are provided, namely an intermediate frame 3 and a sash 2 carrying a glazing element in the form of a pane 4. However, embodiments are conceivable in which only a single secondary frame is present, such as for instance a pane-carrying sash.

[0037] The primary frame 1 comprises a set of frame members including in this embodiment a top frame member, two side frame members and a bottom frame member. Correspondingly, the sash 2 comprises a set of sash members including a top sash member, two side sash members and a bottom sash member. While the primary frame 1 and sash 2 are described as rectangular structures, some principles of the presented concepts may be applicable to other geometrical shapes as well.

[0038] In the embodiment shown, the intermediate frame 3 comprises two arms extending from the top frame member and to a position approximately at the longitudinal centre of the respective side sash member. Embodiments are conceivable in which the intermediate frame forms a coherent U-shape including arms and a cross-bar, or is substantially rectangular, i.e. including four frame members as the primary frame 1 and sash 2.

[0039] The sash 2 of the roof window 100 is openable relative to the primary frame 1 to obtain one or more open positions. In such open position(s), the sash 2 and pane 4 are moved out of the plane of the roof window 100 defined by the primary frame 1. The roof window 100 is operated using an operating assembly, here including a handle 5 at the bottom sash member configured to interact with a locking device or striking plate at the bottom frame member. Additional or alternative operating assemblies are conceivable.

[0040] The sash 2 of the roof window 100 is top-hung in at least a first operational condition which may correspond to a normal use. That is, in this first operational condition, the sash 2 is rotated about a substantially horizontal axis of rotation A at or near the top frame member and top sash member, by means of a hinge assembly comprising a top bearing 60 connecting the primary frame 1 with the secondary frame(s). In the embodiment shown in Fig. 1, the top bearing 60 connects the intermediate frame 3 to the primary frame 1, and the sash 2 is rotatable about the axis of rotation A at the top bearing 60 via the intermediate frame 3. Thus, the sash 2 is rotated about the substantially horizontal first axis of rotation A at or near the top frame member and top sash member between a closed position and an open position. The hinge assembly including the top bearing 60 will be discussed in greater details below.

[0041] In the embodiment shown, the sash 2 is able to rotate through approximately 180° in a second operational condition, about a second horizontal axis of rotation B here positioned approximately half-way between the top and bottom of the roof window 100. This offers the possibility of utilising the roof window 100 as a pivoting roof window but also provides for easy access to the exterior surface of the pane 4 from the interior of the building in which the roof window 100 is installed for cleaning of the window. To achieve this second operational condition, the roof window 100 is provided with a set of a pivot hinge fittings of which a sash hinge part 8 and a frame hinge part 9 of opposite side members of the sash 2 and primary frame 1, respectively, are indicated in Fig. 1.

[0042] It is however conceivable to apply some principles of the presented concepts for roof windows on different types of windows having other opening patterns.

[0043] In the following, the sash 2 will represent the secondary frames and reference will be made to the sash 2 only, even if the secondary frame structure may involve the intermediate frame 3 as shown in Fig. 1 as well.

[0044] The side frame members extend in a length direction L, and the top frame member extends in a width direction W perpendicular to the length direction L. A height direction H extends perpendicular to the length direction L and width direction W. References to the length, height, and width in relation to a lifting device 10 is to be understood as in that the lifting device 10 is arranged in the roof window as intended. Thus, the length, height, and width may also be defined according to the lifting device 10, such as the length direction L being defined by the sliding direction of a sledge in a sledge guide of the lifting device 10, as will be apparent throughout the description.

[0045] The roof window 100 is provided with the lifting device 10 to balance at least part of the weight of the movable components of the roof window 100 and facilitate operation of the window.Lifting device

[0046] Referring now also to Figs. 2 to 4, the lifting device 10 is shown from various sides.

[0047] In Figs. 2 to 4 a lifting device is shown in an open position of a roof window for a 45-degree pitch.

[0048] The lifting device shown in Fig. 2B and Figs. 3 and 4 is a modification of the lifting device shown in Fig. 2A in that it also comprises an adjustment system 17, which will be explained in further detail below.

[0049] The lifting device 10 comprises a spring assembly 11 configured to be coupled to a sledge 12. In turn, the sledge 12 is configured to slide in a sledge guide 13. The sledge guide 13 comprises a first rail 13.1 and a second rail 13.2 which are both shown in Fig. 4.

[0050] In Figs. 2 and 3 the first rail 13.1 of the sledge guide 13 is removed to improve the readability of the drawing figures. Each of the rails 13.1, 13.2 comprises flanges configured to retain the sledge 12 in the sledge guide 13. The two rails 13.1, 13.2 together form a track of the sledge guide 13, wherein the sledge 12 is configured to slide in the track of the sledge guide.

[0051] The lifting device 10 furthermore comprises a lifting arm 14, a sledge arm 15, and a push arm 16. The arms form a linkage mechanism enabling suitable management of forces and movement in the lifting device.

[0052] The lifting arm 14 is inserted between the primary frame 1 and the sash 2 and extends between a first end 14.1 and a second end 14.2. The lifting arm 14 is rotatably connected to the sash 2 by its second end 14.2 at a distance from the top bearing 60. The lifting arm 14 is connected to the sledge guide 13 via the push arm 16.

[0053] The push arm 16 is shown with a first end 16.1 rotatably connected to the sledge guide 13 and a second end 16.2 rotatably connected to the lifting arm 14 at a distance from the first end 14.1 of the lifting arm 14.

[0054] The sledge arm 15 comprises a first sledge arm part 15a and a second sledge arm part 15b arranged on the outside of the lifting arm 14. Correspondingly, the push arm 16 comprises two parts located on the outside of the lifting arm 14 of which one push arm part 16a is shown in Fig. 2.

[0055] Even though only a single lifting device 10 for one side of the roof window is shown, it is understood that a similar lifting device may be arranged on the other side of the roof window as well. By having a lifting device 10 installed on each side frame member an even lift of the sash is provided.

[0056] To adjust the roof window 100 to a specific roof inclination for a selected spring assembly 11, the lifting device 10 of the embodiments shown further comprises an adjustment system 17.

[0057] The adjustment system 17 is connected to the sledge 12 and in turn to the spring assembly 11 by means of the sledge arm 15. The sledge arm 15 extends between a first end 15.1 which is rotatably connected to the sledge 12 and a second end 15.2 which is connected to the adjustment system 17.

[0058] The adjustment system 17 is also connected to the lifting arm 14, and the connection between the sledge arm 15 and the lifting arm 14 via the adjustment system 17 will be described in more detail in the following.

[0059] First, the general functionality of the lifting device 10 will be described in some detail. In Figs. 2 to 4, the sledge 12 is coupled to the spring assembly 11 which is arranged to exert a force on the sledge 12 and thereby act as a force balancing element. The sledge 12 may be uncoupled from the spring assembly 11. This may, as an example, be an advantage during installation of the roof window where a spring force acting on the sledge 12 may make it difficult to handle the roof window. In the cases where the lifting device 10 is installed in the roof window according to its intended use, the sledge 12 and the spring assembly 11 are initially in an uncoupled state. The spring assembly 11 and the sledge 12 are then coupled by opening the roof window resulting in the sledge 12 sliding towards a coupling device such as a hook 11.1 attached to the spring assembly 11. Such a coupling may for example be realised by the sledge 12 comprising a hook plate 12.1 inserted into side flanges of the sledge 12 for coupling the sledge 12 to the spring assembly 11. Opening the roof window results in the sledge 12 engaging with the hook 11.1 and once the roof window is subsequently closed, the sledge 12 will slide in a direction away from the spring assembly 11 towards the top bearing 60 of the roof window while the spring assembly 11, now coupled to the sledge 12, will exert a pulling force on the sledge 12 and provide a resistance against the closing of the roof window, thereby biasing the spring assembly 11. The pulling force of the spring assembly 11 and the weight of the roof window are preferably balanced such that the roof window can be positioned in an open position without forcing it to close due to its own weight or forcing it to open further due to the pulling force applied by the spring assembly. This balance is affected by the inclination of the roof that the roof window is installed in.

[0060] The configuration of the spring or springs in the spring assembly 11 may be dependent on a specific roof inclination. If the roof window is installed on a roof with a roof inclination different than the intended inclination, the spring force from the spring assembly 11 acting on the sledge 12 will not balance the weight of the roof window. In one example, the spring assembly 11 may exert too much force on the window thereby forcing the window to open further. In another example, the spring assembly may be too weak, and the window will close due to its own weight. In both cases, the window may be difficult for the user to operate and potentially hazardous.

[0061] To easily adjust the roof window according to roof inclination, the adjustment system 17 is used. The adjustment system 17 can be used to adjust the roof window for roof inclinations in the range of 15 to 60 degrees.

[0062] As previously mentioned, the top sash member and top frame member are connected by a hinge assembly at least in the first operational condition. A top bearing fitting 6 facilitates this connection. The top bearing fitting 6 comprises a frame attachment section 6.1 a guide attachment section 6.2 extending from the frame attachment section 6.1, as best seen in Fig. 5A. The top bearing 60 is connected to the frame attachment section 6.1. The guide attachment section 6.2 comprises means for attaching the top bearing fitting 6 to the sledge guide 13. The sledge guide 13 is securely fixed to the side frame member the top bearing fitting 6 facilitates the connection between the sash and the frame via the sledge guide 13.

[0063] In Figs. 2 to 5A the top bearing fitting 6 is arranged between the first rail 13.1 and second rail 13.2 of the sledge guide 13. The top bearing 6 is also fixed to both rails 13.1, 13.2, which provides an even load transfer from the spring assembly 11 to the top bearing 6 through the sledge guide 13. However, the lifting device 10 is configured for a selection of different top bearing fittings 6 that serves different purposes, thereby allowing the lifting device 10 to be installed in different types of windows. Fig. 5B shows an alternative top bearing fitting 6' which is only attached to the second rail 13.2. This top bearing fitting can e.g. be used for retrofitting other window models with a lifting device according to this disclosure. Fig. 5C shows the lifting device 10 from Fig. 5A modified with yet another alternative top bearing fitting 6", where the top bearing fitting 6" comprises a hook element 6.3 providing additional attachment to the primary frame 1. This top bearing fitting 6" can e.g. be used when the roof window is installed with a heavy sash such as a 3-layered pane carrying sash. A top bearing fitting that is attached only to the first rail 13.1 may also be envisioned.Adjustment system with worm gear

[0064] In the embodiments shown in Figs. 2 to 4, the adjustment system 17 is configured to adjust the roof window 100 to a specific roof inclination by changing the relative position of a connection point between the lifting arm 14 and the sledge arm 15.

[0065] In the embodiments shown, the connection point is a bushing 17.1. In this context, a connection point is defined as a pivot point between two elements such as between the lifting arm and the push arm, which during normal operation of the roof window i.e. during opening and closing of the window, is configured to perform only a rotating movement. The adjustment system is configured to perform a translational movement of the connection point during adjustment of the adjustment system. In principle, the adjustment system may be configured to perform a translational movement of any one or more connection points between any one of the sledge 12, sledge arm 15, lifting arm 14, sash 2, or push arm 16.

[0066] The adjustment system 17 comprises an adjustment screw 17.2 with a threaded screw shaft 17.3, a worm wheel 17.4, and a screw top 17.5, as best shown in Fig. 6. The adjustment system 17 further comprises a threaded worm 17.6 coupled to the adjustment worm wheel 17.4. The threaded worm 17.6 and the worm wheel 17.4 form a worm gear configured to allow adjustment of the adjustment system 17 from a side of the lifting device from which the user does not have to place themselves or their tools directly between the side frame member of the primary frame holding the spring assembly and the side sash member being held open by the lifting device i.e. by inserting a tool in the threaded worm 17.6 from a direction parallel to the width direction W, as indicated by an arrow T in Fig. 5A, said tool being configured for rotating the threaded worm 17.6 around an axis extending in the width direction w, thereby rotating the worm wheel 17.4 and the threaded screw shaft 17.3 around an axis perpendicular to the width direction as indicated by arrow RW resulting in a translational movement of the bushing 17.1 by the rotation of the threaded screw shaft 17.3, as indicated by arrows TC and RS, respectively, in Fig. 6. The tool may be any suitable tool fitting the selected drive of the worm gear which may for instance be a hex socket screw drive fitting an Allen key as the tool, or a hexalobular socket screw drive fitting a star drive screw bit for insertion into a screwdriver or a power tool.

[0067] The first end 15.1 of the sledge arm 15 is coupled to the bushing 17.1 and the second end 15.2 of the sledge arm 15 is rotatably connected to the sledge 12. The adjustment system 17 is adjusted by rotating the adjustment screw 17.2 such that the bushing 17.1 moves along the length of the threaded screw shaft 17.3 thereby changing the position of the bushing 17.1 and thereby the connection point between the lifting arm 14 and sledge arm 15. This change in position shifts the weight distribution of the lifting device making it possible to adjust the force balance according to the roof inclination.

[0068] The lifting arm 14 comprises a first aperture 14.31 in proximity to its first end 14.1 to accommodate the adjustment screw 17.2. This aperture 14.31 is rectangular-shaped in this embodiment. The worm wheel 17.4 and the threaded worm 17.6 are accommodated in a separate, second aperture 14.32, shown in Fig. 7) in the lifting arm 14. In the embodiment shown, the adjustment screw 17.2 is accommodated within the lifting arm 14 at the screw top 17.5.Structure of components

[0069] As indicated in Figs. 2 to 4, the lifting arm 14 comprises two lifting arm parts 14a and 14b. The lifting arm parts 14a, 14b are fitted together to move as a single lifting arm 14. In the embodiment shown, the lifting arm parts 14a, 14b are formed from metal plates with a thickness of 1.5 mm. As best shown in Fig. 7, the lifting arm part 14a comprises a plurality of openings 14.4 each configured for receiving a collar 14.5 from lifting arm part 14b. The lifting arm part 14b and collars 14.5 are uniformly formed from the same metal plate. Each collar has a collar height larger than the thickness of the lifting arm part 14a. To secure the lifting arm parts to each other, each collar 14.5 is inserted in the corresponding collar receiving opening 14.4 until a part of the collar 14.5 extends from the collar receiving opening on the opposite side from which it was inserted. The extending parts of the collars are deformed in a manner that restricts the collars from being retracted from the openings. The lifting arm parts 14a, 14b are thereby fitted together without the use of rivets and the combined surface area of contact between the two lifting arm parts is increased, which reduces wear and tear on the respective parts.

[0070] The shape of the lifting arm parts 14a, 14b and the position and form of the openings 14.4 have been carefully selected to optimize strength properties and reduce material consumption. The lifting arm parts 14a, 14b abut each other in pre-defined areas.

[0071] In the embodiment of Figs. 2 to 4 and as shown in Fig. 7 each lifting arm part comprises a bent edge 14.6 along its respective periphery and forms half a shell element which together form a closed shell element with a hollow interior. Sufficient strength is retained in each lifting arm part by the bent edge 14.6 spanning the entire circumference of the lifting arm part while reducing the total weight and material consumption of the lifting device. The pre-defined areas are here constituted by the areas in which the collars 14.5 interacts with the counterpart collar receiving openings 14.4, and of the area of the bent edges 14.6.

[0072] Turning now again to Fig. 4, the lifting device 10 of Figs. 1 - 3 is shown from a different angle with both rails 13.1, 13.2 of the sledge guide 13 being visible. The frame 1 is indicated as a dashed box representing the side frame member to which the lifting device 10 is fastened.

[0073] The first rail 13.1 extends substantially the entire length in a length direction L of the side frame member to which the lifting device is attached. The first rail 13.1 is formed from a metal plate having a thickness of 1 mm. The first rail 13.1 is firmly fixed directly to the side frame member and forms part of a side frame reinforcement element. The first rail 13.1 forming part of the sledge guide 13 and part of the side frame reinforcement serves at least three purposes. Firstly, by having the first rail 13.1 as a side frame reinforcement element, a separate frame reinforcement element can be dispensed with compared to the wooden roof windows in production today which have a separate metal reinforcement plate situated at the exterior frame side, thereby reducing the material consumption of the roof window. Secondly, the first rail 13.1 can be arranged closer to the side frame member of the primary frame compared to windows with a separate reinforcement element arranged between the lifting device and the side frame member, thereby reducing the torque on said side frame member. Thirdly, the combined width of the lifting device and side frame reinforcement in the width direction W is reduced making the side sash frame less bulky.

[0074] The second rail 13.2 is here substantially shorter than first rail 13.1 and extends the travelling length of the sledge when the window moves from a closed configuration to a completely open configuration. The second rail 13.2 is formed from a metal plate having a thickness of 1 mm, but other dimensions are conceivable.

[0075] The width of the lifting device 10 in the width direction W from the first rail 13.1 to the second rail 13.2 is substantially 30 mm.

[0076] Turning now to Fig. 8, the lifting device 10 from Figs. 2 - 4 is shown from an end of the lifting device 10 looking in the length direction L along the rails 13.1, 13.2 of the sledge guide 13. The top bearing fitting 6 is arranged at a distance from the first rail 13.1 and second rail 13.2 by means of spacers 18. The top bearing fitting 6 is arranged between the first rail 13.1 and second rail 13.2 and is arranged closest to the second rail 13.2. The top bearing fitting 6 is arranged in a plane P defined by the height direction H and length direction L. Correspondingly, the set of arms and sledge are arranged symmetrically with respect to the plane P. By arranging the set of arms, top bearing fitting 6 and sledge 12 closest to the second rail 13.2, there is sufficient space for installing two roof windows as indicated by a spring assembly 11' of a neighbouring window, each roof window having a lifting device 10 according to the disclosure, next to each other, while still having room for roof cover elements covering the sash and frame elements.

[0077] Referring now to Figs. 9 to 14, a further embodiment of a lifting device of a roof window of the invention will be described. Reference numerals having the same or analogous function as in the above-described embodiments carry the same reference numerals. Only differences to the above-described embodiments will be described in detail.

[0078] As in the above-described embodiment Figs. 2 to 4 and 7, the lifting arm 14 comprises two lifting arm parts 14a and 14b. The lifting arm parts 14a, 14b are fitted together in an assembled condition of the lifting device to move as a single lifting arm 14.

[0079] The lifting arm parts 14a, 14b are made from a plate-shaped material such as metal. However, as will be described in further detail below, the connection between the lifting arm parts 14a, 14b makes it possible to reduce the thickness of the plate-shaped material and the thickness of each lifting arm part 14a, 14b is about 1 mm.

[0080] Different from the above embodiment shown, the lifting arm parts 14a, 14b, each lifting arm part 14a, 14b comprises a set of raised shoulder portions 14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b at mutually facing sides of the lifting arm parts 14a, 14b. During assembly of the lifting arm 14 matching shoulder portions 14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b of the respective sets are brought together to form connection points between the lifting arm parts 14a, 14b.

[0081] In the embodiment shown, the matching shoulder portions 14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b of the respective sets are connected with each other by means of clinching. This may be performed in many ways, for instance by TOX ®< technology.

[0082] In the shown embodiment in which each lifting arm part 14a, 14b comprises a first bearing aperture 14a.16, 14b.16 for the connection to the push arm 16, and a second bearing aperture 14a.2, 14b.2 for the connection to the secondary frame 2, each of the first bearing apertures 14a.16, 14b.16 and the second bearing apertures 14a.2, 14b.2 comprises a bearing flange of a pre-defined height.

[0083] During assembly, the lifting arm parts 14a, 14b are connected to each other by aligning respective first bearing apertures 14a.16, 14b.16 and second bearing apertures 14a.2, 14b.2. This may be carried out by placing the lifting arm parts 14a, 14b on a template with two pins such that the first bearing apertures 14a.16, 14b.16 are aligned with each other and the second bearing apertures 14a.2, 14b.2 are aligned with each other. Subsequently, the clinching of the matching shoulder portions 14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b is performed. Since only the position of the first bearing apertures 14a.16, 14b.16 and second bearing apertures 14a.2, 14b.2 is important to the functionality of the lifting arm 14 in the assembled condition of the lifting device 10, any slight relative movement of matching shoulder portions during clinching does not affect the position of the bearing apertures.

[0084] This is ensured to an even larger extent by the feature, seen most clearly in Fig. 14, that the pre-defined height of the bearing flange of each of the first bearing apertures 14a.16, 14b.16 and the second bearing apertures 14a.2, 14b.2 is such that a gap is formed between the mutually facing bearing flanges of the lifting arm parts 14a, 14b.

[0085] A further feature of the present embodiment is shown most clearly in Figs. 12 and 13, namely that the second aperture 14.32 in the lifting arm 14, configured to receive the worm wheel 17.4 and the threaded worm 17.6, is provided in a punched portion 14.8a, 14.8b in each lifting arm part 14a, 14b in such a way that the punched portion 14.8a, 14.8b is recessed from the mutually facing sides of the lifting arm parts 14a, 14b. In this way, a hollow is formed by the mutually facing concave sides of the punched portions 14.8a, 14.8b.

[0086] Finally, the overall dimensions of the lifting device 10 are minimised by careful selection of the components involved. In the embodiment shown, the adjustment screw 17.2 is provided with such dimensions that the adjustment screw 17.2 is completely accommodated within the first aperture 14.31 of the lifting arm 14. In this way, the only parts of the adjustment device 17 protruding from the contour of the lifting arm 14 are the worm wheel 17.4 and the threaded worm 17.6 as illustrated in Fig. 11.List of reference numerals

[0087] 1 primary frame 2 secondary frame / sash 3 secondary frame / intermediate frame 4 pane 5 operating assembly / handle 6, 6', 6" top bearing fitting 6.1 frame attachment section 6.2 guide attachment section 8 sash hinge part 9 frame hinge part 10 lifting device 11, 11' spring assembly 11.1 hook 12 sledge 12.1 hook plate 13 sledge guide 13.1 first rail of sledge guide 13.2 second rail of sledge guide 14 lifting arm 14a first lifting arm part 14a.2 second bearing aperture (for secondary frame joint) 14a.16 first bearing aperture (for push arm joint) 14b second lifting arm part 14b.2 second bearing aperture (for secondary frame joint) 14b.16 first bearing aperture (for push arm joint) 14.1 first end of lifting arm 14.2 second end of lifting arm 14.2a 14.2b 14.31 first aperture (for adjustment screw) 14.32 second aperture (for worm wheel and threaded worm) 14.4 openings for collars 14.5 collar 14.6 bent edge 14.70a protrusion 14.70b protrusion 14.71a shoulder portion 14.71b shoulder portion 14.72a shoulder portion 14.72b shoulder portion 14.73a shoulder portion 14.73b shoulder portion 14.8a punched portion 14.8b punched portion 15 sledge arm 15a first sledge arm part 15ab second sledge arm part 15.1 first end of sledge arm 15.2 second end of sledge arm 16 push arm 16a first push arm part 16.1 first end of push arm 16.2 second end of push arm 17 adjustment system 17.1 bushing 17.2 adjustment screw 17.3 threaded screw shaft 17.4 worm wheel 17.5 screw top 17.6 threaded worm 18 spacer 60 top bearing 100 roof window A first axis of rotation B second axis of rotation L length direction W width direction H height direction P plane TT arrow for insertion of tool RW arrow for rotation of worm RS arrow for rotation of threaded screw shaft TC arrow for translation of bushing

Examples

Embodiment Construction

[0033]In the following detailed description, a preferred embodiment of the present invention will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. It may also be noted that, for the sake of clarity, the dimensions of certain components illustrated in the drawings may differ from the corresponding dimensions in real-life implementations.

[0034]It is noted that terms such as "up", "down", "left-hand", "right-hand", "exterior", "interior", "outer", "inner" are relative and refers to the viewpoint in question. In general, when referred to an exterior side, this relates to a side of a roof window in the mounted condition facing the outdoors or external side of the building. Conversely, an interior side refers to a side facing the internal side of the building, i.e. typically a subjacent room including any light shaft. Terms...

Claims

1. A roof window (100), particularly for installation in or on a roof surface having an inclination, comprising a primary frame (1) comprising a top frame member, two side frame members, and a bottom frame member, at least one secondary frame (2), a lifting device (10) comprising a sledge (12), a sledge guide (13), a set of arms (14, 15, 16), and a spring assembly (11), wherein the spring assembly (11) is configured to be coupled to the sledge (12), and the sledge guide (13) comprises a first rail (13.1) and a second rail (13.2) characterised in that at least one of the first rail (13.1) and the second rail (13.2) forms part of a side frame reinforcement element attached to one of the side frame members.

2. A roof window according to claim 1, wherein the first rail (13.1) extends substantially the entire length of the side frame member.

3. A roof window according to any one of the preceding claims, wherein the set of arms (14, 15, 16) comprises a lifting arm (14), a sledge arm (15), and a push arm (16), wherein the sledge arm (15) is connected to the sledge (12) and the lifting arm (14), and the push arm (16) is connected to the sledge guide (13) and the lifting arm (14), and the lifting arm (14) is further connected to the secondary frame (2).

4. A roof window according to claim 3, wherein the lifting arm (14) comprises a first lifting arm part (14a) and a second lifting arm part (14b) abutting each other in pre-defined areas.

5. A roof window according to claim 4, wherein the first lifting arm part (14a) and the second lifting arm part (14b) each comprises a bent edge (14.6) along its respective periphery and forms half a shell element which together form a closed shell element with a hollow interior.

6. A roof window according to any one of the preceding claims, wherein the lifting device further comprises an adjustment system (17).

7. A roof window according to claim 6, wherein the adjustment system (17) of the lifting device (10) comprises a worm gear comprising a threaded worm (17.6) and a worm wheel (17.4) configured to rotate around perpendicularly extending axes by arranging the threading of the threaded worm (17.6) between cogs of the worm wheel (17.4), and wherein the worm wheel (17.4) of the adjustment system (17) is connected to an adjustment screw (17.2) including a threaded screw shaft (17.3).

8. A roof window according to claim 7, wherein the adjustment system (17) is configured for adjusting the position of a connection point (17.1) between the lifting arm (14) and the sledge arm (15).

9. A roof window according to claim 8, wherein the connection point is a bushing (17.1) arranged on the threaded screw shaft (17.3) of the adjustment screw (17.2) of the adjustment system (17), and wherein the bushing (17.1) is coupled to a first end (15.1) of the sledge arm (15), and wherein a second end (15.2) of the sledge arm (15) is rotatably connected to the sledge (12).

10. A roof window according to claim 9, wherein the adjustment system (17) is at least partly arranged in a set of apertures (14.31, 14.32) in the lifting arm (14), and wherein the set of apertures comprises a first aperture (14.31) configured to receive the adjustment screw (17.2) and a second aperture (14.32) configured to receive the worm wheel (17.4) and the threaded worm (17.6).

11. A roof window according to any one of the preceding claims when dependent on at least claim 4, wherein each lifting arm part (14a, 14b) comprises a set of raised shoulder portions (14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b) at mutually facing sides of the lifting arm parts (14a, 14b), and wherein matching shoulder portions (14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b) of the respective sets form connection points between the lifting arm parts (14a, 14b) in an assembled condition of the lifting device (10), said matching shoulder portions (14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b) of the respective sets being connected with each other by means of clinching.

12. A roof window according to any one of the preceding claims when dependent on at least claim 4, wherein each lifting arm part (14a, 14b) comprises a first bearing aperture (14a.16, 14b.16) for the connection to the push arm (16), and a second bearing aperture (14a.2, 14b.2) for the connection to the secondary frame (2), each of the first bearing apertures (14a.16, 14b.16) and the second bearing apertures (14a.2, 14b.2) comprising a bearing flange of a pre-defined height.

13. A roof window according to claim 12, wherein the lifting arm parts (14a, 14b) are connected to each other by aligning respective first bearing apertures (14a.16, 14b.16) and second bearing apertures (14a.2, 14b.2) with each other and performing the clinching of said matching shoulder portions (14.70a, 14.70b, 14.71a, 14.71b, 14.72a, 14.72b, 14.73a, 14.73b), the pre-defined height of the bearing flange of each of the first bearing apertures (14a.16, 14b.16) and the second bearing apertures (14a.2, 14b.2) being preferably such that a gap is formed between the mutually facing bearing flanges of the lifting arm parts (14a, 14b).

14. A roof window according to any one of claims 10 to 13, wherein the second aperture (14.32) in the lifting arm (14) is provided in a punched portion (14.8a, 14.8b) in each lifting arm part (14a, 14b), the punched portion (14.8a, 14.8b) being recessed from the mutually facing sides of the lifting arm parts (14a, 14b).

15. A roof window according to claim 14, wherein the adjustment screw (17.2) is provided with such dimensions that the adjustment screw (17.2) is completely accommodated within the first aperture (14.31) of the lifting arm (14).

Images