EP4390030A1

EP4390030A1 - Roof window with a lifting device and method of assembling a lifting device

Info

Publication number: EP4390030A1
Application number: EP23218127.1A
Authority: EP
Inventors: Michael Galsgård Holm; Terkel ØHLENSCHLÆGER
Original assignee: VKR Holding AS
Current assignee: VKR Holding AS
Priority date: 2022-12-19
Filing date: 2023-12-19
Publication date: 2024-06-26

Abstract

In the roof window (100), the lifting device (10) further comprises a lifting arm (14) inserted between the primary frame (1) and the at least one secondary frame (2). The lifting arm (14) has a first end (12) rotatably connected with a sledge (30) slidably connected with the primary frame (1) in a sledge guide (16) and a second end (13) rotatably connected with the at least one secondary frame (2). The lifting device (10) further comprises a spring assembly (20) configured to be coupled to the sledge (30), an adjustment system (50) and an adjustment arm (52).

Description

Technical Field

The present invention relates to a roof window with a stationary primary frame, at least one secondary frame such as a sash and/or intermediate frame, and a lifting device comprising a lifting arm inserted between the primary frame and the at least one secondary frame. The invention furthermore relates to a method of assembling a lifting device.

Background Art

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 centre, 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, either for cleaning or for providing an alternative manner of operation. Roof windows of the top-hinged type have a first hinge axis 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 hinge axis. Typically, one hinge of the hinge arrangement will be located at either side of the roof window to define a substantially horizontal hinge axis.
Examples of top-hinged windows with a second operational condition are for instance disclosed in Applicant's WO-A-89/10460 , EP 0 733 146 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, 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.
In roof windows in which the operation takes place either entirely or partially about a hinge axis at the top, it is known to balance at least part of the weight of the movable components by means of a lifting device. The purpose of this arrangement is to facilitate opening the window, and the dimensions may be chosen so that the spring can retain the top-hinged frame in equilibrium in a desired opening position.
Such a lifting device is for instance disclosed in the Applicant's WO2019/101281 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.
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

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 ease of operability.
In a first aspect, this is achieved with a roof window of the kind mentioned in the introduction, which is further characterised in that the lifting arm has a first end rotatably connected with a sledge slidably connected with the primary frame in a sledge guide and a second end rotatably connected with the at least one secondary frame. The lifting device further comprises a spring assembly configured to be coupled to the sledge. The lifting device further comprises an adjustment system and an adjustment arm, wherein the adjustment system is mounted to the sledge guide and the adjustment arm has a first end rotatably connected to the lifting arm and a second end connected to the adjustment system, such that the adjustment arm and the lifting arm are connected at an angle with a value (α₁). The angle value (α₁) assumes a second angle value (α₂) by adjusting the position of the second end of the adjustment arm by means of the adjustment system.
The adjustment system provides a system for adjusting the roof window for different roof inclinations. When the spring assembly is coupled to the sledge one or more springs in the spring assembly exerts a pulling force on the sledge. This results in the first end of the lifting arm experiencing a pull and a rotation around the connection point with the adjustment arm. As a result, the lifting arm is forced into a position with its longitudinal end substantially perpendicular to the sliding direction of the sledge in the sledge guide resulting in an opening of the roof window. The force exerted by the lifting arm on the secondary frame is related to the positioning of the secondary lifting arm relative to the lifting arm and spring. Thus, when the position of the second end of the adjustment arm changes relative spring assembly and the lifting arm the force exerted by the lifting arm on the secondary frame also changes. By providing the roof window with an adjustment system according to this disclosure the roof window can be balanced to a roof inclination in the range of 15° - 65°.
The adjustment system may comprise an adjustment screw.
The adjustment system may further comprise an adjustment base mounted to the sledge guide, the adjustment screw being fixedly connected to the adjustment base, the adjustment screw extending along a length axis and/or being configured to rotate about the length axis.
The adjustment screw provides a possible mechanism for adjusting the position of the adjustment arm. The adjustment screw may be fixed to an adjustment base. The adjustment screw can rotate about its longitudinal axis. The adjustment base may be fitted in the sledge guide. Alternatively, the adjustment screw may be fixed to the sledge guide through the adjustment base. The adjustment base may comprise plastic.
The second end of the adjustment arm is fitted to the adjustment screw such that the adjustment arm travels along the length direction of the adjustment screw when the adjustment screw is screwed upon. The adjustment screw may further comprise a cogwheel at one of its ends, preferably at the end located in proximity with the sledge guide when in a mounted position. The cogwheel may be adapted to cooperate with the outer geometry of a mechanical tool.
The adjustment system may further comprise an adjustment bushing wherein the second end of the adjustment arm is connected to the adjustment screw through the adjustment bushing, such that the adjustment bushing is configured to move axially on the adjustment screw.
The adjustment bushing allows for minimum friction connected between the adjustment screw and the adjustment arm. As the adjustment arm is adjusted on the adjustment screw, the angle between the adjustment arm and the lifting arm changes. Simultaneously, the angle between the adjustment arm and the adjustment screw may change. The bushing provides a suitable mechanism that allows such a rotation.
The bushing may comprise a cylindrical or cyclical body engaging with the adjustment screw via a through hole. The through hole of the adjustment bushing may have an inner geometry to engage with an outer bushing of the adjustment screw. The adjustment bushing may further have at least one end part projecting from the body and configured to engage with a track or a slot on the sledge guide. This track or slot may be called engagement slot.
The adjustment system may further comprise a disc configured to be in connection with and/or adjacent to the second end of the adjustment arm. The disc may further be adjacent and/or connected to the adjustment bushing such that the disc encompasses the body of the adjustment bushing and the end part projects from the disc.
The sledge guide may further comprise an adjustment slot, wherein the adjustment system is configured to be accommodated in the adjustment slot.
In order for the adjustment arm to travel along the adjustment screw an adjustment slot may be provided in the sledge guide such that the adjustment bushing and the adjustment arm can be adjusted without colliding with the sledge guide. Additionally, such an adjustment slot may provide a way to visually inspect the adjustment level of the adjustment system by acting as a way to observe the adjustment screw, the adjustment bushing or the adjustment arm. Indications such as numerical values, letters or marks for the adjustment may be provided along the adjustment slot to indicate the position of the adjustment arm on the adjustment screw to the user according to the roof inclination. The adjustment slot may be linear. The adjustment slot may alternatively be slightly curved. The adjustment slot may run in direction that intersect with the direction of the sliding direction of the sledge. It may run in direction that is perpendicular to the sliding direction of the sledge.
The sledge guide may further comprise a first and a second flange extending in a height direction perpendicular to the longitudinal direction. The sledge guide may further comprise a rivet holding the two flanges of the sledge guide firmly together.
The adjustment arm may comprise a first adjustment arm and a second adjustment arm fastened on opposite sides of the adjustment screw.
The first and second adjustment arm may preferably be similarly shaped. The first and second adjustment arm may preferably be fixed to each other. The first and second adjustment arm may be fixed to each other with some distance. They may alternatively be abutting each other and be symmetrically positioned around a central plane P. The sledge guide and the lifting arm may extend in the central plane P. The central plane P may extend in a length direction and in a height direction, the height direction being perpendicular to the length direction. The central plane P may extend through the middle of the width of the sledge guide. The central plane P may therefore extend through the middle of the sledge positioned in the sledge guide. The sledge may be arranged in the sledge guide to slide in a direction of the central plane P.
The link connection between the adjustment arm and the sledge guide may be positioned in the central plane P. This is to be understood such that the resulting force of the adjustment arm acting on the sledge guide is substantially in a direction defined by the central plane P. It may be envisioned that the two adjustment arms are not structurally symmetric around the central plane P but that the resulting force from the adjustment arm acting on the sledge guide is still in a direction defined by the central plane P. It may also be envisioned that the adjustment arm may be equipped with sliding discs or other components not contributing significantly to the forces acting in the link between the adjustment arm and the sledge guide and in the link between the adjustment arm and the lifting arm.
Symmetrically arranged around the central plane P is in general to be understood as arranged such that the direction of the resulting force acting on the symmetrically arranged feature or features extends in a direction defined by the central plane P.
The lifting arm may comprise a first lifting arm and a second lifting arm arranged on opposite sides of the adjustment arm. The first lifting arm and the second lifting arm may be arranged symmetrically around the central plane P. The first lifting arm and the second lifting arm may be similarly shape. The first lifting arm may be shaped in form mirroring the shape of the second lifting arm. The sash wheel may be arranged between the first lifting arm and the second lifting arm. The lifting arm may be connected to the sledge symmetrically around the central plane P. The first lifting arm may be connected to the sledge at a point not comprised in the central plane P. The second lifting arm may then be connected to the central plane P in a mirror point of the connection point of the first lifting arm with regards to the central plane P.
The sledge may comprise a sledge wheel. A sledge wheel may allow steering of the sledge along the length of the sledge guide. The sledge wheel may be provided substantially next to the connection between the sledge and the lifting arm. The lifting arm may be connected to the sledge through the sledge wheel. By providing the sledge wheel close to the lifting arm, a greater stability of the sledge is achieved. The sledge wheel may additionally add support for the sledge in the sledge guide. The sledge may additionally and/or alternatively be provided with one or more runners. The one or more runners mounted on the sledge may provide additional support for the sledge in the sledge guide. The runners may be made of a polymer. The runners may comprise glass fibre. The runner may be configured to be connected to the first end of the lifting arm and be mounted on the sledge.
The lifting arm may further comprise sliding discs arranged on opposite sides of the lifting arm. The sliding discs reduce the distance between the lifting arm and the sledge guide thereby adding stability to the lifting device when the lifting arm travels in the sledge guide. The sliding discs may comprise polymer. The sliding discs may be fastened to the lifting arm through holes on the lifting arm. The sliding discs may be fastened to the lifting arm by an adhesive.
The sledge guide may comprise an opening for insertion of a mechanical tool such as a tip end of a drill bit arranged to engage with the adjustment system.
Such opening may be a through hole or a blind hole on the outer surface of the sledge guide. The mechanical tool may be any tool that can provide an adjustment of the adjustment system such that the second end of the adjustment arm is displaced related to the sledge guide through the adjustment system. The mechanical tool may be fitted to the adjustment screw of the adjustment system.
This may provide an easy adjustment method of the roof window that can be done with common tools available to a person installing a window. The opening may be provided in the sledge guide. The opening may be provided in the sledge guide in a position close to an end of the adjustment screw. There may be two or more openings in the sledge guide for receiving a mechanical tool fitted to the adjustment system. There may be such openings provided symmetrically on two sides of the sledge guide. This makes it possible to install the lifting device in more than one position and still being able to access the adjustment system in case one opening is blocked. It may be envisioned that the lifting device is provided in both sides of the roof window. In a case where the roof window has been installed in a roof of a building, the adjustment system may best be reached by the installer or user of the window through the opening of the window. In such a case the same lifting device may be used in both sides of the room window with equally easy access to the adjustment system in both lifting devices.
The sledge guide may further comprise openings such as holes adapted to receive screws for mounting the sledge guide onto the window frame.
The roof window may further comprise a coupling mechanism with a first coupling member and a second coupling member, wherein the first coupling member is comprised in the sledge and the second coupling member is comprised in the spring assembly.
The first coupling member may be a hook element. The second coupling may be a receiving means. It is also conceivable to form the hook element in or on the sledge system and providing the spring assembly with the receiving means. Furthermore, within the context of the present application, the terms "hook element" and "receiving means" are to be interpreted as encompassing also other suitable types of male-female connectors
In a second aspect, a method of assembling a lifting device for a roof window according to the first aspect is provided. The method comprises the steps of:

shaping the sledge guide from a metal sheet via sheet metal forming, such that a first side of the sledge guide and a second side of the sledge guide are symmetrically formed in relation to a central plane P through the sledge guide;
connecting the first end of the adjustment arm with the lifting arm, and the first end of the lifting arm with the sledge with rivets;
connecting the adjustment system to the second end of the adjustment arm with the adjustment bushing;
applying an external force to elastically deform the sledge guide to increase the distance between the first side of the sledge guide and the second side of the sledge guide;
inserting the sledge and the adjustment system in the sledge guide such that the adjustment bushing fits in the adjustment tracks;
removing the externally applied force, thereby allowing the sledge guide to resume its original shape, thereby locking the position of the sledge and the adjustment system in the transverse direction;
and inserting a sledge guide rivet in the sledge guide connecting the first side and the second side of the sledge guide, the sledge guide rivet preventing the sledge guide to deform and release the adjustment bushing.

An a third aspect a method of adjusting a lifting device of a roof window according the first aspect is provided. The method comprises the steps of:

uncoupling the spring assembly (20) from the sledge (30);
opening the roof window;
applying an external force to the adjustment screw (53) through an opening in the sledge guide (16), such that the angle value (α₁) assumes a second angle value (α₂).

Other presently preferred embodiments and further advantages will be apparent from the subsequent detailed description and drawings.

Brief Description of Drawings

In the following description, embodiments of the invention will be described with reference to the drawings, in which

Fig. 1A is a perspective view of a roof window in an embodiment of the invention, seen from an interior side;
Fig. 1B is perspective of the roof window of Fig. 1A, seen from an exterior side;
Fig. 1C is a perspective cross-sectional view of a roof window in another embodiment, with the sash in an open position.
Fig. 2 is a perspective view of a lifting device for a roof window in an embodiment according to the invention in a first operational condition.
Fig. 3A is a side view of a lifting device for a roof window in an embodiment according to the invention in a closed position of the window and with the sledge unattached to the spring assembly.
Fig. 3B is a side view of a lifting device for a roof window in an embodiment according to the invention in an open position of the window and with the sledge attached to the spring assembly.
Fig. 4 is a close-up perspective view of a lifting device for a roof window in an embodiment according to the invention showing the sash wheel mounted in a lifting arm and in connection with a wheel guide.
Fig. 5 is close-up perspective view of a lifting device for a roof window in another embodiment according to the invention showing the sash wheel mounted in a lifting arm and in connection with a wheel guide.
Fig. 6 is a close-up perspective view of a lifting device for a roof window in an embodiment according to the invention showing part of a sledge guide, an adjustment arm and lifting arm and how these are connected.
Fig. 7 is a close-up perspective view of a lifting device for a roof window in an embodiment according to the invention showing part of a sledge guide, an adjustment arm and lifting arm and how these are connected from another angle.
Fig. 8 is a close-up perspective view of a lifting device for a roof window in an embodiment according to the invention showing part of a sledge guide, an adjustment arm and lifting arm and how these are connected from another angle.
Fig. 9 is a perspective view of a lifting device for a roof window in an embodiment according to the invention showing the central plane P.
Fig. 10 is a side view of a lifting device for a roof window in an embodiment according to the invention in one operational condition where the adjustment arm is adjusted at an angle α₁ in relation to the lifting arm.
Fig. 11 is a side view of a lifting device for a roof window in an embodiment according to the invention in another operational condition where the adjustment arm is adjusted to an angle α₂ in relation to the lifting arm by introducing a tip end of a mechanical tool such as a drill bit into an opening in the sledge guide, where the drill bit is fitted to an adjustment screw connected to the adjustment arm.
Fig. 12A shows a mechanical tool interacting with an adjustment system for a lifting device for a roof window in an embodiment according to the invention adjusted for a specific roof inclination.
Fig. 12B shows a mechanical tool interacting with an adjustment system for a lifting device for a roof window in an embodiment according to the invention adjusted for a roof inclination different from the one shown in Fig. 12A.

Description of Embodiments

In the following, embodiments of the lifting device and roof window will be described in further detail. When referring to the Figures, the terms up, down, upwards, downwards, top and bottom are taken relative to how the figures are displayed. A front view is taken from the hinge and viewing towards the frame. A view from behind is therefore taken as viewed from the frame towards the hinge. A longitudinal direction is, if nothing else is mentioned, longitudinal along the length of a member. It is to be understood that the arrangement shown in a horizontal orientation is not the normal orientation as the window is installed in an inclined roof.
Referring initially to Figs 1A and 1B, a roof window 100 is shown. The roof window 100 is intended to be installed in an inclined roof surface (not shown).
The roof window 100 comprises a primary frame 1, a secondary frame such as a sash 2, and a pane 4. In the shown embodiment only one secondary frame is present; however, a further secondary frame in form of an intermediate frame may be provided, which is well-known from roof windows that are top-hinged during normal use but which pivot for cleaning. The primary frame 1 comprises a set of frame members including a top frame member, two side frame members and a bottom frame member. Correspondingly, the sash 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.
The pane 4 comprises a number of edge portions generally associated to members of the sash 2 as will be described in further detail below. An exterior pane surface 4e defines a plane of the roof window 100 in an assembled condition of the roof window 100. The assembled condition of the roof window 100 is achieved when main components of the primary frame 1 and sash 2 have been assembled and the primary frame 1 and sash 2 are connected to each other, for instance in an installed position when the roof window 100 is ready for use. Correspondingly, an assembled condition of the sash 2 is achieved once main components of the sash 2 have been assembled, and an assembled condition of the primary frame 1 when main components of the primary frame 1 are assembled. The term "main components" is to be understood as encompassing primary parts of the roof window necessary to perform all operational functions, and not including accessories or auxiliary equipment.
An interior pane surface 4i faces the interior, typically a room of a building subjacent the roof surface in which the roof window 100 is installed.
In the embodiments shown, the sash 2 is openable relative to the primary frame 1, to obtain one or more open positions. In such open positions, the sash 2 and pane 4 are moved out of the plane of the roof window 1. As will be described in the following, the sash 2 is shown as being top hung, i.e. during normal use, the sash 2 is rotated about a substantially horizontal hinge axis at or near the top frame member and top sash member. It is however conceivable to apply some principles of the presented concepts for roof windows on different types of windows having other opening patterns, or being provided as fixed skylights.
Further details shown in Fig 1A include an operating assembly, here shown as a handle. Other operating assemblies may be present as well.
Also shown is a representative mounting bracket forming part of a plurality of mounting brackets forming a load-transferring connection between the roof window 100 and a surrounding roof structure (not shown). Such a roof structure may include rafters and battens, plywood or other construction materials.
An insulating frame is shown. Insulation by an insulating frame is optional and may be provided along only some of the frame members or as shown surrounding all four frame members.
Referring to Fig. 1C it is shown that the roof window 100 furthermore comprises a hinge assembly.
The hinge assembly is configured in such a way that it allows the sash 2 to be top hung in a first operational condition corresponding to normal use. That is, during normal use the sash 2 is rotated about a substantially horizontal first hinge axis at or near the top frame member and top sash member between a closed position and an open position.
Fig. 2 shows a lifting device 10 installed in a roof window with a primary frame 1 and a sash 2. The lifting device shown in Fig. 2 is assembled according to the second aspect. The lifting device is installed between the primary frame 1 and the sash 2 and comprises a sledge guide 16 fixed to the primary frame 1 and a lifting arm 14 with a first end 12 rotatably fixed to a sledge 30 sliding in the sledge guide 16. In the embodiments shown in Figs. 2 - 5 and 8 - 11, a sash wheel 40 is attached to the second end 13 of the lifting arm 14. Other types of connections may be envisioned. The second end 13 of the lifting arm 14 may be attached to the sash 2 by means of a rivet or otherwise rotatably fastened to the sash 2. The second end 13 of the lifting arm 14 may alternatively comprise a secondary sledge sliding in a secondary sledge guide provided on the sash 2. In Fig. 2 the sash wheel 40 is attached to the lifting arm 14 by means of a wheel rivet 42. The sash wheel 40 is in a rolling connection with the sash 2 by means of the sash wheel 40. Other means of attachment may be envisioned. In the embodiment shown in Fig. 3A the sash wheel 40 rolls on a wheel guide 41. The wheel guide 41 acts as a rail for the sash wheel during opening and closing of the window. The wheel guide 41 also provides protection for the sash 2 as the sash wheel rolls on the sash 2 during opening and closing of the roof window. The lifting arm 14 is also attached to the sledge guide 16 through an adjustment arm 52. The adjustment arm 52 is at one end rotatably attached to lifting arm 14. In Fig. 3A the adjustment arm 52 is attached to the lifting arm 14 at a point approximately equally distanced between the first end 12 of the lifting arm 14 and the second end 13 of the lifting arm. The adjustment arm 52 can in other embodiments by rotatably attached to the lifting arm at a point closer towards the first end 12 of the lifting arm 14 or at a point closer towards the second end 13 of the lifting arm 14. As shown in Figs. 2 - 3 and 6 - 11 the adjustment arm 52 is connected to the sledge guide 16 through an adjustment system 50.. The sledge 30 is attached to a spring assembly 20 which is arranged to exert a force on the sledge 30. Generally, the roof window may comprise a coupling mechanism with a first coupling member and a second coupling member as detailed in Fig. 3A. The first coupling member may be comprised in the sledge 30 and the second coupling member may be comprised in the spring assembly 20. The first coupling member may be a hook element. The second coupling may be a receiving means. In the embodiments detailed in Fig. 3A - 3B, the first coupling member on the sledge is a receiving means and the second coupling member on the spring assembly is a hook element. It is also conceivable to form the hook element in or on the sledge system and providing the spring assembly with the receiving means. Furthermore, within the context of the present application, the terms "hook element" and "receiving means" are to be interpreted as encompassing also other suitable types of male-female connectors.
The sledge 30 may be uncoupled from the spring assembly 20. This may, as an example, be an advantage during installation of the roof window where a spring force acting on the sledge 30 may make it difficult to handle the roof window. In cases where the lifting device 10 is comprised in the roof window according to its intended use, the sledge 30 and the spring assembly 20 are initially in an uncoupled state as shown in Fig. 3A. The spring assembly 20 and the sledge 30 are then coupled by opening the roof window resulting in the sledge 30 sliding towards a coupling device such as a hook attached to a spring comprised in the spring assembly 20. Opening the roof window results in the sledge 30 engaging with the hook, as shown in Fig. 3B, and once the roof window is subsequently closed, the sledge 30 will slide back in a direction away from the spring assembly 20 and the spring now coupled to the sledge 30 will exert a pulling force on the sledge 30 and provide a resistance against the closing of the roof window. The pulling force of the spring and the weight of the roof window are preferably balanced such that the roof window can be positioned in an open position without closing due to its own weight or opening further due to the pull from the spring in the spring assembly. This balance is also influenced by the roof inclination of the roof that the roof window is installed in. The spring in the spring assembly 30 may be adjusted to balance the roof window for a specific roof inclination. If the roof window is installed in a roof with a roof inclination different than the intended inclination, the spring force acting on the sledge will not be balanced to the weight of the window. In one example, the spring may exert to much force on the window thereby forcing the window to open further. In another example, the spring is too weak, and the window will close due to its own weight. Both scenarios are both uncomfortable for the user and potentially hazardous. To easily adjust the roof window according to roof inclination an adjustment system as shown in Figs. 2 - 3 and 6 - 11 is comprised in the roof window. The adjustment system is installed to adjust the position of the second end of the adjustment arm 52 in the sledge guide 16.
In Figs. 3A and 3B a sliding disc 43 on the lifting arm 14 is present. A further sliding disc may be arranged on the other side of the lifting arm 14 as well. The sliding disc reduces the distance to the sledge guide 16 and adds stability to the lifting arm as it travels from an open to a closed position or vice versa.
An adjustment rivet 57 - better shown in Fig. 3 - connects the lifting arm 14 to the adjustment arm 52 firmly, while enabling their rotational movement with respect to each other.
Fig. 4 shows a sash wheel 40 in a wheel guide 41 where the wheel guide 41 is provided with longitudinal flanges projecting from both longitudinal edges of the wheel guide thereby forming a channel which the sash wheel 40 can move in. Fig. 5 shows an alternative embodiment of the lifting device 10 where the wheel guide 41 is provided as a plate. Generally, the second end of the lifting arm may also comprise flanges that partly shells the sash wheel, as shown in Fig. 5.
Figs. 6 and 7 each shows a part of the lifting device with a lifting arm 14 extending from the sledge 30. In these embodiments the lifting arm 14 comprises a first lifting arm 141 and second lifting arm 142 with the two lifting arms 141, 142 arranged on opposite sides of the adjustment arm 52. The two lifting arms 141, 142 are preferably similarly shaped with both the sash wheel and adjustment arm arranged between the two lifting arms 141, 142. The wheel rivet 42 displayed in Figs. 4 and 5 may be used as a mean to keep the two lifting arms 141, 142 fixed to each other. Other means may preferably also be used to keep the two lifting arms 141, 142 fixed to each other. The two lifting arms 141, 142 may be fixed to each other through the attachment to the adjustment arm 52 and through the attachment to the sledge 30. Each of these means of fixing the two lifting arms to each other may be used in combination and individually. As also depicted in Figs. 6 and 7, the adjustment arm 52 may comprise a first adjustment arm 521 and a second adjustment arm 522. The two lifting arms 141, 142 may be symmetrically arranged according to a central plane P, shown in Fig. 9. Similarly, the two adjustment arms 521, 522 may be symmetrically arranged according to the central plane P.
Figs. 6 and 7 additionally show the adjustment system 50. Fig. 6 particularly shows an adjustment slot 55 with an adjustment bushing 54 engaged with the adjustment slot 55. In this embodiment the adjustment slot 55 is a linear slit in the sledge guide 16 limiting the adjustment bushing 54 and thereby the adjustment arm 52 to travel in a linear direction in the adjustment slot 55. The adjustment slot 55 may be slightly curved such that the adjustment arm 52 travels in a semi-circle. The longitudinal direction of the adjustment slot 55 may additionally or alternatively be arranged in a direction substantially in parallel with the sliding direction of the sledge. The longitudinal direction of the adjustment slot 55 may in other embodiments travel in a direction that is perpendicular to the sliding direction of the sledge 30 in the sledge guide 16.
Fig. 7 shows a sledge guide rivet 58 for added stability of the lifting device 10. The sledge guide rivet 58 locks the two sides of the sledge guide to each other and simultaneously ensure that the adjustment system also shown in Fig. 7 is kept in place.
Fig. 8 shows a lifting device 10 for a roof window from a top perspective view. It is clearly shown that in this embodiment the first and the second adjustment arms 521, 522 are distanced and separated from each other at their attachment to the adjustment system 50, but are attached to each to other at a point located close to their attachment to the adjustment system 50 and up until their attachment to the lifting arms 141, 142. Alternatively, the adjustment arms 521, 522 may each have a longer inclined portion and an attachment point closer to the attachment to the lifting arm.
Fig. 9 shows a perspective view of the lifting device in an open position, where a central plane P is illustrated. The imaginary central plane P extends in a longitudinal or length direction L and height direction H and is defined as the plane where the respective forces exerted by the lifting arm and the adjustment arm are balanced. The central plane P intersects the sledge guide 16 in the middle of the width of the sledge guide 16. The width is defined as extending in the width direction, the width direction being perpendicular to the length direction. The two lifting arms 141, 142 are therefore symmetrically arranged with respect to a central plane P. In Fig. 9 the sledge guide is shown as extending along the length direction that defines the central plane P. The lifting device is shown in an open position and the lifting arm extends substantially in the height direction in this open position. When the lifting device 10 is in the closed position, such as shown in Fig. 3A, the lifting arm extends substantially along the length direction together with the sledge guide. Similarly, the two adjustment arms 521, 522 are symmetrically arranged with respect to the central plane P. The two lifting arms 141, 142 are positioned such that the forces exerted by the lifting arm 14 onto the central plane P are balanced. Furthermore, the sledge guide 16 is symmetrical with respect to the central plane P. The lifting arm 14 comprises a first lifting arm 141 and a second lifting arm 142 arranged symmetrically with respect to the central plane P.
Figs. 10 and 11 show a lifting device from a side view. In Fig. 10, the adjustment arm 52 is adjusted such that its second end is in a position creating an angle α₁ between the lifting arm 14 and the adjustment arm when the window is in an open position.
In Fig. 11 the roof window is in the same open position as in Fig. 10 and the second end of the adjustment arm 52 is adjusted such that the angle between the adjustment arm 52 and the lifting arm 14 is an angle α₂. In Fig. 11 it is also visualized how the adjustment arm 52 can be adjusted by means of a mechanical tool 60 such as a drill bit fitted and rotated into an opening 161 in the sledge guide 16 of the lifting device 10, also shown in Figs. 2, 3. The adjustment arm 52 shown in Fig. 10 is arranged for a roof window installed in a roof with an inclination of approximately 65°, whereas the roof window shown in Fig. 11 is arranged for a roof window installed in a roof with an inclination of approximately 15°. By adjusting the adjustment arm 52 to a position in between these two extremes the forces can be balanced for roof inclinations varying in the range of 15° to 65°. The adjustment system may also adjust the lifting device to operate smoothly in roof windows installed in lower or higher roof inclinations, such as 10° or 70°.
Figs. 12A - 12B show an example of how a mechanical tool and an adjustment system may interact. In Fig. 12A a mechanical tool 60 is shown to fit into the opening 161 of the sledge guide 16. The mechanical tool 60 has a drill bit fitted to the adjustment screw 53. Fig. 12A shows how an adjustment bushing 52 may be fitted onto the adjustment screw 52. Fig. 12A also shows how the adjustment bushing 52 is fitted to an adjustment slot 55. By turning the mechanical tool 60 in this embodiment shown as a drill bit, the adjustment screw 53 is turned. This results in the adjustment bushing 52 being moved along the length direction of the adjustment screw 53 and as well to move along in the adjustment slot. As can be seen from Fig. 12A, the adjustment slot 55 has indications showing what roof inclination the adjustment system 50 is adjusted for. In Fig. 12A the adjustment system 50 is adjusted to a roof inclination of approximately 15°. In Fig. 12B the adjustment system 50 is adjusted to a roof inclination of approximately 65°. In Fig. 12B it is shown how the adjustment arm 52 may be connected to the adjustment bushing 52.
The invention is not limited to the embodiments shown and described in the above, but various modifications and combinations may be carried out.

List of reference numerals

1: Primary frame
2: Secondary frame
4: Pane
4i: Interior pane surface
4e: Exterior pane surface
10: Lifting device
12: First end of lifting arm
13: Second end of lifting arm
14: Lifting arm
141 First lifting arm
142 Second lifting arm
16: Sledge guide
161 opening
20: Spring assembly
30: Sledge
31: Sledge wheel
40: Sash wheel
41: Wheel guide
42: Wheel rivet
43: Sliding discs
50: Adjustment system
52: Adjustment arm
521 First adjustment arm
522 Second adjustment arm
53: Adjustment screw
54: Adjustment bushing
55: Adjustment slot
56: Adjustment base
57: Adjustment arm rivet
58: Sledge guide rivet
60: Mechanical tool

100: Roof window

P: Central plane
H: Height direction
L: Length direction

α1: Angle
α2: Angle

Claims

A roof window (100), comprising
a stationary primary frame (1),

at least one secondary frame (2), such as a sash and/or intermediate frame, and

a lifting device (10) comprising a lifting arm (14) inserted between the primary frame (1) and the at least one secondary frame (2), the lifting arm (14) having a first end (12) rotatably connected with a sledge (30) slidably connected with the primary frame (1) in a sledge guide (16) and a second end (13) rotatably connected with the at least one secondary frame (2), the lifting device (10) further comprising a spring assembly (20) configured to be coupled to the sledge (30),

the lifting device (10) further comprising an adjustment system (50) and an adjustment arm (52),

wherein the adjustment system (50) is mounted to the sledge guide (16) and the adjustment arm (52) has a first end rotatably connected to the lifting arm (14) and a second end connected to the adjustment system (50), such that the adjustment arm (52) and the lifting arm (14) are connected at an angle with a value (α₁),

wherein the angle value (α₁) assumes a second angle value (α₂) by adjusting the position of the second end of the adjustment arm (52) by means of the adjustment system (50).
A roof window (100) according to any of the preceding claims, wherein the adjustment system (50) comprises an adjustment screw (53).
A roof window (100) according to claim 2, wherein the adjustment system (50) further comprises an adjustment bushing (54), wherein the second end of the adjustment arm (52) is connected to the adjustment screw (53) through the adjustment bushing (54), such that the adjustment bushing (54) is configured to move axially on the adjustment screw (53).
A roof window (100) according to claim 3, wherein the adjustment system (50) further comprises an adjustment base (56) mounted to the sledge guide (16), the adjustment screw (53) being fixedly connected to the adjustment base (56), the adjustment screw (53) extending along a length axis and/or being configured to rotate about the length axis.
A roof window (100) according to any one of claims 3 and 4, wherein the sledge guide further comprises an adjustment slot (55), wherein the adjustment system is configured to be accommodated in the adjustment slot (55).
A roof window (100) according to any one of claims 2 to 5, wherein the adjustment arm (52) comprises a first adjustment arm (521) and a second adjustment arm (522) fastened on opposite sides of the adjustment screw (53).
A roof window (100) according to any of the preceding claims, wherein the lifting arm (14) comprises a first lifting arm (141) and a second lifting arm (142) arranged on opposite sides of the adjustment arm (52).
A roof window (100) according to any of the preceding claims, wherein the sledge (30) comprises a sledge wheel (31).
A roof window (100) according to any of the preceding claims, the lifting arm (14) further comprising sliding discs (43) arranged on opposite sides of the lifting arm (14).
A roof window (100) according to any of the preceding claims, wherein the sledge guide (16) comprises an opening (161) for insertion of a mechanical tool (60) such as a tip end of a drill bit arranged to engage with the adjustment system (50).
A roof window (100) according to any of the preceding claims, further comprising a coupling mechanism with a first coupling member and a second coupling member, wherein the first coupling member is comprised in the sledge and the second coupling member is comprised in the spring assembly.
A method of assembling a lifting device (10) for a roof window (100) according to any of claims 1 to 11 comprising the steps of:
shaping the sledge guide (16) from a metal sheet via sheet metal forming, such that a first side of the sledge guide and a second side of the sledge guide are symmetrically formed in relation to a plane (P) through the sledge guide (16);

connecting the first end of the adjustment arm (52) with the lifting arm (14), and the first end (12) of the lifting arm (14) with the sledge with rivets;

connecting the adjustment system (50) to the second end of the adjustment arm (52) with the adjustment bushing (54);

applying an external force to elastically deform the sledge guide (16) to increase the distance between the first side of the sledge guide and the second side of the sledge guide;

inserting the sledge (30) and the adjustment system (50) in the sledge guide (16) such that the adjustment bushing (54) fits in the adjustment tracks (55);

removing the externally applied force, thereby allowing the sledge guide (41) to resume its original shape, thereby locking the position of the sledge (30) and the adjustment system (50) in the transverse direction;

and inserting a sledge guide rivet (58) in the sledge guide connecting the first side and the second side of the sledge guide, the sledge guide rivet (58) preventing the sledge guide to deform and release the adjustment bushing (54).
A method of adjusting a lifting device (10) of a roof window (100) according to any of claim 1-11, wherein the method comprises the steps of:
uncoupling the spring assembly (20) from the sledge (30);

opening the roof window;

applying an external force to the adjustment screw (53) through an opening (161) in the sledge guide (16), such that the angle value (α₁) assumes a second angle value (α₂).