EP3959405B1

EP3959405B1 - Window and assembly comprising a handle free frameless sash

Info

Publication number: EP3959405B1
Application number: EP20717856.7A
Authority: EP
Inventors: Olivier Bouesnard; Pierre Schneider; Geoffroy VAN DER REST
Original assignee: AGC Glass Europe SA
Current assignee: AGC Glass Europe SA
Priority date: 2019-04-24
Filing date: 2020-04-08
Publication date: 2025-11-26
Anticipated expiration: 2040-04-08
Also published as: EP3959405A1; WO2020216620A1

Description

TECHNICAL FIELD

The present invention is in the general field of windows, including openable windows such as casement windows, tilting windows and glass doors as well as non-openable windows. Windows typically comprise a sash coupled to a fixed frame mounted in an opening of a wall. The present invention concerns more particularly windows comprising a handle free frameless sash, for improved safety.

BACKGROUND OF THE INVENTION

Windows typically comprise a sash coupled to a fixed frame mounted in an opening (or tunnel) of a wall (or similar). A sash typically comprises one, two, or more glazings coupled to a sash frame extending over a part or a whole of a glazing perimeter. The sash typically comprises an inner glazing and an outer glazing having respectively an inner surface bounded by an inner glazing perimeter and by an outer surface bounded by an outer glazing perimeter. The sash frame is typically made of wood, metal, polymer, or composite material. The sash frame can be an inner frame or an outer frame. An "inner frame" is positioned between the glazings so as to be at least partially concealed in the inner glazing perimeter and the outer glazing perimeter. An "outer frame" by contrast, is fixed to the external surface of the inner and/or the outer glazing facing the inner and/or outer environment of the window. The outer frame is always visible at least from one of the inner or outer environment of the window. Typically, sashes comprising one or more glazings with an inner frame and no outer frame, are designated as "frameless sashes". Frameless sashes are available on the market since several years and are generally characterized by larger transparent see-through areas than corresponding sashes of same dimensions provided with an outer frame. In frameless sashes, the inner frame is designed to fulfil the functions of a standard outer frame such as accommodating the hardware required for locking the frameless sash in a closed or a semi-open position (e.g., tilting) while achieving mechanical, thermal and tightness performances of the frameless sash.
In particular, for locking a window, a door or the like, an opening system comprises typically a handle designed to rotate-most often using an actuating element, a drive system or a door lock socket. In this configuration, the handle is passing through a hole in the inner and/or outer glazings. The handle is then always visible at least from one of the inner or outer environment of the window.
The market trend in the field of frameless sashes windows is the continuous improvement of their aesthetics through the transparent see-through area as well as through the opening system. Besides expanding the see-through area by the use of an inner frame, attention is also paid to the visual impact of the fixed frame. For instance, the fixed frame may be flush with the inner glazing surface and/or with the outer glazing surface or the fixed frame may be inboard from the inner glazing surface and/or with the outer glazing surface. To further improve the aesthetic and enhance the full glassy look aspect, the inner frame must also accommodate the hardware required for locking the frameless sash in a closed or a semi-open position (e.g., tilting). For casement windows, hinges allowing opening and closing of the window by rotation of the sash relative to the fixed frame can also be enclosed within the inner frame so as not to be visible from either side of the window. In particular configurations, the hardware required for locking the window does no comprise the typical handle passing through the inner and/or the outer glazings.
When the frameless sash is flush with the fixed frame and free of a passing through handle, there is a risk that the inner glazing and/or outer glazing might fall because the bonding between the inner and/or outer glazings and the sash elements fail. Indeed, considering the frameless configuration (free of an outer frame), the inner frame ensures by itself the mechanical, thermal and tightness performances of the frameless sash. The inner and outer glazings, can be exposed to severe stresses such as wind constraints, repeated opening and closing of the window, ... leading to bonding failure between the inner and/or outer glazings and the sash elements. The main technical challenge is hence to identify the right way to design a window with a complete frameless aspect or glassy look while ensuring safety for users, especially for users living in the inner environment. In the closed position, the surfaces of the inner and/or outer glazings being flush with the inner and/or outer faces of the fixed frame profiles are no more retained in case of bonding failure between the glazings and sash elements. In the particular case of a movable inward frameless sash in open position wherein the inner and/or outer glazings are free of a passing through handle, the glazings are no more retained in case of bonding failure. Furthermore in open position, the sharp glassy corners of the inner and/or outer glazings are not protected as the frameless sash is free of outer frame. Hence, it may happen that the user bump into said sharp glassy corners.
DE 197 33 415 A1 relate to a frame less window or door with a pivotally motorized drive. A complete frameless aspect is for example disclosed in EP2436865 describing a frameless sash having an inner and an outer glazings glued onto an insert made of hollow profiles and wherein the fixed frame is inboard from the inner glazing. In WO2018178425 , a frameless sash having a motorized locking system managed by a control module in connection with sensors is described. The hardware required for locking the window is then free of an handle passing through a hole in glazings. The enclosure formed by glazed surfaces and opening practicable is constituted by continuous flat surfaces without handles or projections.
Therefore, there is still a need for the development of a window having an improved design to fully ensure safety for users, especially for users in the inner environment while providing improved aesthetics - offering continuous smooth surfaces between the frameless sash and the fixed frame without any protrusion nor any significant recesses, and while maintaining mechanical, thermal and tightness performances of the frameless sash.

SUMMARY OF THE INVENTION

The present invention is defined in the appended independent claims and relates to a window according to claim 1 and to an assembly according to claim 17. Preferred embodiments are defined in the dependent claims.
In particular, the present invention relates to a window extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Z, comprising an handle free frameless sash and a fixed frame.
The handle free frameless sash comprises: an inner glazing having an inner glazing external surface and an inner glazing internal surface, and an outer glazing having an outer glazing external surface and an outer glazing internal surface. The inner and outer glazings are free of an outer frame and free of a passing-through handle, are separated by a gap defined within a peripheral spacer, have respectively a bottom edge and a top edge extending parallel to the longitudinal axis, X, and lateral edges extending parallel to the vertical axis, Z, and have respectively inner and outer peripheral bands and inner and outer peripheral corners. The inner glazing external surface is separated from the outer glazing external surface, by a sash thickness measured in the direction normal to the plane, P. The handle free frameless sash comprises an inner frame positioned in a volume between the inner and outer glazings and between the peripheral spacer and the edges of the inner and outer glazings respectively.
The fixed frame defines a frame opening, has an outer face and an inner face defining a frame thickness measured in the direction normal to the plane, P.
Within the handle free frameless sash of the window of the present invention, the inner face of the fixed frame is flush with the inner glazing external surface, when the handle free frameless sash is in closed position. The handle free frameless sash comprises a inner retaining safety device for retaining the inner glazing external surface to the inner frame.
The inner retaining safety device is preferably positioned on an inner peripheral band and/or on an inner peripheral corner, more preferably on an inner peripheral corner of the inner glazing.
In a preferred embodiment, the inner glazing further comprises a hole, preferably a chamfered hole, and the inner retaining safety device is preferably a fastening mean passing through the hole of the inner glass, more preferably is a screw.
In a preferred embodiment, the handle free frameless sash further comprises a bottom inner supporting safety device for supporting the bottom edge, of the inner glazing onto the inner frame. Such bottom inner supporting safety device has preferably a cross section in the direction normal to the plane, P; comprising a bottom transverse portion extending transverse to the bottom edge of the inner glazing, and abutting to the inner frame. Such bottom inner supporting safety device can also have a cross section in the direction normal to the plane, P, comprising (a) a bottom transverse portion extending transverse to the bottom edge of the inner glazing and, (b) a first vertical portion, extending along the vertical axis, Z, having a top end and a bottom end, said vertical portion being connected to the bottom transverse portion and abutting the inner glazing internal surface and the inner frame. In a further preferred embodiment, the cross section of the bottom inner supporting safety device further comprise a top transverse portion extending transverse to the top end of the first vertical portion and abutting the inner frame.
In a preferred embodiment, the bottom edge of the inner or outer glazing is stepped outwardly with respect to the bottom edge of the outer or inner glazing, more preferably the bottom edge of the inner glazing is stepped outwardly with respect to the bottom edge of the outer glazing, defining at least an interspace extending between the inner and outer glazings from the inner frame to the bottom edges of the inner and outer glazings.
In a preferred embodiment, the inner retaining safety device of the handle free frameless sash of the window of the present invention, is the bottom inner support safety device as described above, wherein the cross section of said bottom inner support safety device further comprises a second vertical portion extending along the vertical axis, Z, from the bottom transverse portion and abutting the inner glazing external surface.
In a preferred embodiment, the handle free frameless sash further comprises a second inner retaining safety device. This second inner retaining safety device has a cross section in the direction normal to the plane, P; wherein the cross section comprises (a) a lateral transverse portion extending transverse to the lateral edge of the inner glazing and to the inner frame, and (b) a first longitudinal portion extending along the longitudinal axis, X, from the lateral transverse portion and abutting the inner glazing external surface. In a further preferred embodiment, the second retaining safety device is positioned on an inner peripheral corner and is connected to the bottom inner supporting safety device as described above, preferably is connected to the bottom inner supporting safety device wherein its cross section further comprises a second vertical portion extending along the vertical axis, Z, from the bottom transverse portion and abutting the inner glazing external surface.
In a preferred embodiment, the handle free frameless sash further comprises a third inner retaining safety device. This third inner retaining safety device has a cross section in the direction normal to the plane, P; wherein the cross section comprises (a) a top transverse portion, extending transverse to the top edge of the inner glazing and to the inner frame, and (b) a first vertical portion extending along the vertical axis, Z, from the top transverse portion and abutting the inner glazing external surface.
Typically, the handle free frameless sash can be coupled to the fixed frame in one of the following manners: (a) the handle free frameless sash is fixedly coupled to the fixed frame in the closed position, or (b) the handle free frameless sash is movingly coupled to the fixed frame such that the handle free frameless sash can reversibly move with respect to the fixed frame from the closed position to an open position, wherein the handle free frameless sash leaves open at least a portion of the frame opening.
In a preferred embodiment, the handle free frameless sash further comprises one intermediate glazing forming a three glazing unit formed by an inner, intermediate and an outer glazing separated from one another by two gaps, each gap being defined within a peripheral spacer.
In a preferred embodiment, when the handle free frameless sash is in the closed position, the outer face of the fixed frame is flush with the outer glazing external surface. In a preferred embodiment, the handle free frameless sash further comprises an outer retaining safety device for retaining the outer glazing surface to the inner frame. Preferably, the outer retaining safety device is positioned on an outer peripheral band and/or on an outer peripheral corner of the outer glazing perimeter, preferably on an outer peripheral corner.
The present invention further relates to an assembly comprising a wall separating an inner environment from an outer environment and provided with a through opening in the form of a tunnel defined by a tunnel perimeter, and at least a window as described above. The wall has a thickness measured in the direction normal to the plane, P; which is greater than or equal to the thickness of the fixed frame. The inner face of the fixed frame is flush with the wall and/or the outer face of the fixed frame is flush with the wall, preferably the inner face of the fixed frame is flush with the wall.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the following detailed description taken in conjunction with the accompanying drawings in which :

Figure 1 : shows a casement window with two frameless sashes opening by rotation about vertical axes.
Figures 2 (a) and (b) : show cross-sectional views of windows according to one embodiment of the present invention wherein the handle free frameless sash comprises a screw as the inner retaining safety device.
Figure 3 (a) to (d) : show cross-sectional views of handle free frameless sashes wherein the inner retaining safety device is a screw and further comprising a bottom supporting safety device, according to various embodiments of the present invention.
Figure 4 (a) to (c) : shows cross-sectional views of handle free frameless sashes wherein the inner retaining safety device is a bottom inner supporting safety device according to alternative embodiments of the present invention.
Figure 5 : shows a perspective view of two connected inner safety devices: one inner retaining safety device is a bottom inner supporting safety device and the other is a second retaining safety device, according to a further embodiment of the present invention.
Figure 6 (a) to (c) : show perspective views of handle free frameless sashes illustrating different combinations of inner retaining safety device(s) with outer retaining safety device(s) according to further various embodiment of the present invention.
Figure 7 : shows a cross-sectional view of a handle free frameless sash forming a triple glazing unit according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a window with an improved safety profile, especially safety for users living in the inner environment.
It has been surprisingly found that the retaining safety device of the window of the present invention by retaining the inner glazing to the inner frame, provides such required safety profile. Frameless sash by definition do not comprise an outer frame. Therefore, it is the inner frame that is designed to fulfil the standard functions of the outer frame such as accommodating the hardware required for locking the frameless sash. In particular, the inner retaining safety device by fixing the inner glazing to the inner frame, creates a mechanical bonding between the fixed frame and the inner glazing through the hardware. It has been further surprisingly found that the retaining safety device allows the flush alignment between the handle free frameless sash and the fixed frame and thereby contribute significantly to the total glassy look aesthetics required by the market. Furthermore, the retaining safety device within the handle free frameless window of the present invention maintains the mechanical, thermal and tightness performances of the frameless sash.
Therefore, the window of the present invention allows to provide new aesthetic and secure concepts in the building industry. These and other advantages are described in more details in the following sections.
By "handle free frameless sash", it is hereby meant a sash comprising an inner and outer glazings and an inner frame. It does not comprise an outer frame, nor a passing through handle. The terms "inner frame" are understood to mean a sash frame which is positioned between the inner and the outer glazings so as to be at least partially concealed in an inner and an outer glazing perimeters. The terms "outer frame" by contrast, are understood to mean the sash frame which is fixed to external surfaces of the inner and the outer glazings facing respectively an inner and an outer environment of the window. The terms "free of passing through handle" are understood to mean that the inner and outer glazings do not comprise a handle passing through the inner glazing nor passing through the outer glazing nor passing through the inner and outer glazings.
The term "flush" used in relation to surfaces, is herein understood to mean that a surface is aligned to another surface to form a continuous plane, with a flush tolerance thickness, measured in the direction normal to the plane, P, which is at most +/- 5 mm, preferably at most +/- 3mm, more preferably at most +/- 2mm and even more preferably by 0 mm.
The terms "retaining safety device" are understood to encompass devices capable of maintaining the inner and/or outer glazing(s) in their mounting state even in case of bonding failure between the inner and/or the outer glazing and the sash elements. The bonding is typically assured by the structural resin.
Windows according to the invention include openable windows such as casement windows, like single sash windows and stulp windows, tilt-and-rotate windows and glass doors in general as well as non-openable windows. In particular and for expanding the see-through area of the opening of the wall, it is preferred that the window is a stulp window.
By "stulp window", it is meant that the casement window does not comprise central mullion(s) (i.e., a central pillar forming part of the fixed frame) and comprise at least two sashes. These two sashes have respectively one lateral edge facing the other when the sashes are in the closed position.
Within the present invention, the term "a " means one or more.

Handle free frameless Sash

As depicted in Figure 1 , the window of the present invention extends along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Z. It comprises an handle free frameless sash (10) and a fixed frame (20). The handle free frameless sash has generally four edges defining typically a rectangle. The handle free frameless sash has indeed no outer frame an is free of passing-through handle.
The handle free frameless sash comprises at least an inner glazing, an outer glazing and an inner frame.
Typically the inner and outer glazings of a frameless sash are adhesively bonded by a structural resin (16) to the sash elements such as the inner frame and peripheral spacers, rather than mechanically anchored to the sash frame.
Each inner and outer glazings have respectively an inner glazing perimeter and an outer glazing perimeter as well as an inner glazing surface and an outer glazing surface. Likewise, each inner and outer glazings have respectively a bottom edge, BotE, and a top edge, TopE, both extending parallel to the longitudinal axis, X, and lateral edges, LatE, both extending parallel to the vertical axis, Z. Furthermore, each inner and outer glazing have respectively inner and outer peripheral bands (141,142) and inner and outer peripheral corners (151,152). Said peripheral bands and corners are extending respectively inwardly from bottom, top and lateral edges of the inner and outer glazings, preferably to reach at most the peripheral spacer.
When in closed position, the window of the present invention can be used to close the opening of a wall (30) separating an inner environment from an outer environment. Within the handle free frameless sash, the inner glazing is facing the inner environment while the outer glazing is facing with the outer environment.
As illustrated in Figure 2 (a) and (b) , the handle free frameless sash within the window of the present invention comprises inner (101) and outer glazings (10n) separated by a gap (121) defined within a peripheral spacer (131). The inner and outer glazings surfaces are both provided with a glazing internal surface facing the gap designated as the inner glazing internal surface (IGis) and the outer glazing internal surface (OGis) as well as a glazing external surface facing the inner or outer environments designated as the inner glazing external surface (IGes) and the outer glazing external surface (OGes).
The window of the present invention comprises a fixed frame (20) defining a frame opening, having an outer face and an inner face and having a frame thickness, W20, measured in the direction normal to the plane, P. Typically for forming a sealed contact to provide air-and water-tightness, between the handle free frameless sash (10) and its corresponding fixed frame (20), the window comprises typically sealing elements (40) for sealingly closing the frame opening when the frameless sash is in the closed position. When the frameless sash closes the frame opening, the inner and outer glazing perimeters of the frameless sash are coupled to inner and outer frame perimeters of the fixed frame, respectively.
In an preferred embodiment of the present invention, to improve further the sealed contact between the handle free frameless sash and its corresponding fixed frame and thus improving further the air- and water-tight performances of the window of the present invention, the surface of the inner glazing is greater or smaller than the surface of the outer glazing. Such surface differential will result in one or more of the top, bottom and/or lateral edges of the inner or outer glazing being stepped outwardly with respect of the corresponding edges of the outer or inner glazing. In this stepped configuration, the inner frame defines an interspace (17) extending between inner surfaces of the inner and outer glazings from the inner frame to the bottom edges of the inner and outer glazings respectively. It is further preferred that the bottom edge of the inner glazing is stepped outwardly with respect to the bottom edge of the outer glazing as illustrated in Figures 2(b). In particular, for even higher sealing performances, it is more preferred that at least the bottom edge and the lateral edges of the inner glazing are stepped outwardly with respect to the corresponding edges of the outer glazing.
The handle free frameless sash of the present invention has a sash thickness, W10, measured in the direction normal to the plane, P, extending between the external surface of the inner glazing, IGes, and the external surface of the outer glazing, OGes. With the development of new wall building materials, the current trend is to reduce the thickness of the walls for increased inner floor area, while maintaining the thermal performance of the windows and walls. Ten years ago, the average wall thickness was about 200 mm. It is, nowadays about 150 mm. To follow this trend, it is preferred that the thickness of the handle free frameless sash of the present invention, W10, is not more than 85 mm, more preferably not more than 75 mm and even more preferably not more than 70 mm.

Inner frame

As depicted in Figures 2 to 7 , the handle free frameless sash comprises an inner frame (11) extending over a whole perimeter of the frameless sash. The inner frame is positioned within a volume defined between the inner and outer glazings and, between the peripheral spacer and the edges of the inner and outer glazings respectively. Typically, said volume is further filled with a structural resin (16). By structural, it is meant the ability to bear and transfer loads, in particular related to the weight of the glazing and to thermal expansion stresses. For example, the structural resin can be a silicon resin, which generally combine good mechanical properties and high thermal insulating properties and ability to form air- / water-tight seals.
The inner frame can be made of wood, polymer, fibre reinforced composite, or metal such as steel or aluminium. It is, however, preferred that the inner frame is not made of aluminium for reasons of optimized thermal insulation. The inner frame encloses hardware required for locking / unlocking the handle free frameless sash in an open or closed position. In particular, hinges for opening the handle free frameless sash, can also be contained within the inner frame. Within the handle free frameless sash of the present invention, the hardware required for locking the window does not comprise a handle passing through the inner and/or the outer glazings.
In order to hide the inner frame and most of the hardware enclosed therein from sight from both inner and outer environments separated by the window, it is preferred to opacify the inner and outer peripheral bands (141,142) and inner and outer peripheral corners (151,152) over a height extending inwardly from the bottom, top and lateral edges of the inner and outer glazings, respectively, preferably to at least the peripheral spacer (131) contacting the corresponding glazing. Preferably, the inner and outer peripheral bands and the inner and outer peripheral corners have a visible light transmission, TL, at least 50% lower than the inner glazing (101) and the outer glazing (10n), respectively, outside of the respective inner and outer peripheral bands and corners. Preferably, the inner and outer peripheral bands and inner and outer peripheral corners are opaque. For example, the inner and/or outer peripheral band and corner can be enamelled, or etched or sand-blasted to create a texture yielding a translucent inner and outer peripheral band and corner. The inner and/or outer peripheral band and corner can also be made (partially) opaque or translucent by applying a film. The inner and/or outer peripheral band and corner can also comprise decorative patterns. To increase the transparent see-through area of the handle free frameless sash (i.e., the see-through area of the window when the handle free frameless sash is in the closed position), the height of the peripheral band, measured from the bottom, top or lateral edges toward the centre of a glazing is preferably comprised between 10 and 100 mm, more preferably between 15 and 80 mm, most preferably between 20 and 60 mm.

Fixed frame

The handle free frameless sash (10) is coupled to a fixed frame (20), the fixed frame defining a frame opening. The fixed frame has the inner face facing the inner environment, and the outer face facing the outer environment. The fixed frame has a thickness, W20, measured in the direction normal to the plane, P, from the inner face to the outer face. The frame opening accommodates the handle free frameless sash or sashes when the window is closed and brings in fluid communication the inner and outer environments when the window is open. The fixed frame is formed by one or more fixed frame profiles. In particular, the fixed frame is composed of the fixed frame profiles covered a by a cover plate. Indeed, the fixed frame profile can be made of a weathering-sensitive material such as wood or some polymers or fibre reinforced polymer composite materials which are sensitive to UV-radiation or to hydrolysis. In this configuration, it is current to apply a cover plate over at least a portion of the fixed frame profile facing the outer environment. This cover plate must be made of a weathering-resistant material, such as metal (e.g., aluminium, (stainless) steel), UV-resistant polymers or composites, or even ceramics. In particular and for achieving mechanical, thermal and tightness performances of the frameless sash, it is preferred that the thickness, W20, of the fixed frame of the window is greater than or equal to the thickness, W10, of the handle free frameless sash, W20 ≥ W10, as illustrated in Figure 2

(a) and (b).

Coupling of the Frameless Sash to the Fixed Frame

The fixed frame comprises receiving elements for coupling the handle free frameless sash to the fixed frame in the closed position, closing the frame opening. The receiving elements are designed to accommodate the hardware of the inner frame of the handle free frameless sash.
When the handle free frameless sash is in the closed position within the present invention, the inner face of the fixed frame is flush with the inner glazing external surface, IGes, of the handle free frameless sash forming a continuous surface on the window facing the inner environment.
In a preferred embodiment, it can be further contemplated that the outer face of the fixed frame is also flush with the outer glazing external surface, OGes, of the handle free frameless sash forming a continuous surface on the side of the window facing the outer environment. The flush alignment on one or both sides of the window (i.e between the inner glazing, and the inner faces of the fixed fame or between both the inner and outer glazings, and the inner and outer faces of the fixed fame respectively), offers particularly aesthetic design opportunities. It has further the advantage of low amounts of dirt accumulation and, at the same time, easier cleaning of the window, since both sides of the window form a continuous smooth surface with no protrusions or recesses where the dirt can accumulate, and which can be cleaned with a continuous driving of a squeegee over the surfaces. In a particular preferred embodiment, the flush tolerance thickness, is at most +/- 2mm and preferably by 0 mm, resulting in the thickness, W20, of the fixed frame of the window being equal to the thickness, W10, of the handle free frameless sash (W20 = W10).
According to an alternative embodiment of the present invention, the frameless sash is fixedly coupled to the fixed frame in the closed position. The fixed coupling can however be reversible, by dismantling the frameless sash from the fixed frame but it cannot open and close like a typical window.
According to an preferred embodiment, the handle free frameless sash is movingly coupled to the fixed frame such that the handle free frameless sash can reversibly move with respect to the fixed frame from the closed position to an open position wherein the handle free frameless sash leaves open at least a portion of the frame opening, with the handle free frameless sash remaining coupled to the fixed frame.
In particular, it is preferred that at least the bottom edge of the inner glazing is stepped outwardly with respect to outer glazing. This gives the great advantage of enhancing sealing of the interface between the handle free frameless sash and the fixed frame. It is more preferred that the handle free frameless sash is movingly coupled to the fixed frame and the inner glazing surface is greater than the outer glazing surface.
In the embodiment wherein the handle free frameless sash could be open, the window of the present invention can further comprise a mechanically, pneumatically or electrically actuating device for reversibly moving the handle free frameless sash with respect to the fixed frame from the closed position to the open position and reverse. The actuating device can be activated with a switch located on the window or on the wall supporting the window. Alternatively, or additionally, the actuating device can be activated by means of a remote-control system, including a receiver integrated in the handle free frameless sash and/or the fixed frame for actuating the moving of the handle free frameless sash. The remote-control system can preferably also control any functionality of the glazing as discussed in the section entitled "glazing", such as an electrochromic device, a multimedia connection, an antenna, communication means, a TV set, a light source including a LED, a loudspeaker, a sensor, and the like.

Retaining safety device

As illustrated in Figures 2 , 3 , 4 , 6 and 7 , the handle free frameless sash within the window of the present invention, comprises an inner retaining safety device (171) to confer safety for users, while offering continuous surfaces between the handle free frameless sash and the fixed frame without any protrusion nor any significant recesses on the inner environment while maintaining mechanical, thermal and tightness performances. The inner retaining safety device (171) is intended to retain the inner glazing external surface, IGes, to the inner frame (11).
In order to hide the inner retaining safety device from sight from inner environment, the inner safety retaining device is typically positioned on the inner peripheral band or on the inner peripheral corner of the inner glazing, preferably on the inner peripheral corner. In particular and for enhancing the safety of the users within the inner environment, one or more inner safety retaining devices can be used. In a preferred embodiment, two inner safety retaining devices are positioned on diagonally opposite peripheral corners.
In a preferred embodiment, the inner glazing further comprises a hole, preferably a chamfered hole and the inner retaining safety device is a fastening mean passing through the hole of the inner glass. The fastening mean can be a screw or a bolt and is passing through the inner glazing and is then tightened to the inner frame for retaining the inner glazing external surface to the inner frame. In a preferred embodiment, fastening mean device is positioned on the top edge peripheral band, even more preferably in the middle of the top edge peripheral band.
In particular, it is preferred that the fastening mean is a screw passing through the inner glass for a cost effective production process and more preferably a screw passing through a chamfered hole in the inner glass for achieving the flush configuration with a flush tolerance which is at most 2 mm and even is 0 mm. The shape of the hole in the inner glass can be round, oval, rectangular or square for allowing anti clockwise rotation when the screw is tightened by clockwise rotation.
Selection criteria of the screw materials may be calculated according to conventional calculations based upon the strength of material and will determine: size, required strength, resistance to corrosion, joint material, cost and temperature. The screw material is typically made of brass, nickel, bronze, aluminium, steel, stainless steel or a polymer material. In particular, if the screw material is made of steel or stainless steel, a resilient material can optionally be added such as a polymer material like a polyamide ring positioned between the screw and the hole in the inner glazing for imparting a smooth contact and limiting stress constraints.
Within the present invention, the inner retaining safety device is a cable positioned on the inner peripheral corner. For retaining the inner glazing external surface to the inner frame, the cable being fixed to the inner frame via sealing elements and/or fastening means, is extending from the bottom and/or top edges to lateral edges of the inner glazing external surface.
To further improve the safety of the handle free frameless sash, the weight of the sash depending on the thickness and dimensions of its glazings (101, 10n) could also be carefully considered. Indeed, the weight of the handle free frameless sash is one further element that may lead to the bonding failure of structural resin between the inner glazing and the sash elements.
Therefore, in a preferred embodiment of the present invention, the handle free frameless sash further comprises a bottom inner supporting safety device (1811) for supporting the inner glazing bottom edge (BotE) onto the inner frame as illustrated in Figures 3 (a) to (d), Figures 4 (a) to (c) and Figure 6 (b) to (d). By supporting safety device, it is meant a device that help supporting the weight of the glazings of the handle free frameless sash. The bottom inner supporting safety device is positioned at the bottom edge of the inner glazing for supporting the inner glazing while maintaining the flush alignment between the inner glazing external surface, IGes, and the inner face of the fixed frame when the handle free frameless sash is in closed position, and maintaining the mechanical performances of the handle free frameless sash. For window of large dimensions and/or weight, it has been found that the addition of bottom inner supporting device(s) relieve some of the constrains that would otherwise be supported by the inner retaining safety device(s) allowing to design inner retaining safety devises of reduced dimension that would otherwise interfere with the flush alignment. The bottom inner supporting device is fixed onto the inner frame with mechanical means such as screws, rivets or snap-fits, preferably with screws or rivets, or with a combination of mechanical and adhesive means such as an adhesive resin or a double-sided adhesive tape or foam.
In particular for further enhancing the safety of the users, it is preferred to position one inner retaining safety device within one peripheral corner along the bottom edge of inner glazing and one bottom inner supporting safety device at the opposite peripheral corner along the bottom edge of inner glazing. It is more preferred to position one inner retaining safety device within one peripheral corner along the top edge of inner glazing and one bottom inner supporting safety device at the diagonally opposite peripheral corner along the bottom edge of inner glazing.
Selection criteria of the bottom inner supporting safety device include : size, required strength, resistance to corrosion, joint material, cost and temperature. The bottom inner supporting safety device is typically made of aluminium, steel, stainless steel, wood, or polymer material such as a fibre reinforced composite with a polymeric matrix. For higher mechanical properties, it is preferred that the bottom inner supporting safety device be made of a fibre reinforced composite with a polymeric matrix. The reinforcing fibres can be glass, aramid or carbon fibres. For a cost point of view, glass fibres are preferred, but if high mechanical properties are required, carbon fibres can be used instead. Similarly, for high toughness, aramid fibres can be used. A mixture of fibres can also be envisaged. The reinforcing fibres can be chopped fibres, and the bottom inner supporting safety device can be produced by extrusion of a chopped fibre filled polymer. For higher mechanical properties, it is, however, preferred to use continuous fibres. The bottom inner supporting safety device can then be produced continuously by pultrusion. The polymeric matrix can be a thermoset, such as an epoxy, polyester, polyurethane, and the like. Alternatively, it can be a thermoplastic, such as a polyolefin (e.g., PE, PP), a polyamide (e.g., PA6, PA66, PA12), a polyester (e.g., PET, PEN), polyurethane, or blends or mixtures thereof.
As illustrated in Figure 3(a) , in a preferred embodiment, the bottom inner supporting safety device (1811) has a cross section in the direction normal to the plane, P; wherein said cross section comprises a bottom transverse portion, P11a, extending transverse to the bottom edge, BotE, of the inner glazing and abutting to the inner frame (11).
For enhancing further the safety of the frameless sash considering the weight of the handle free frameless, the bottom inner supporting safety device can comprise further portions as described below.
As illustrated in Figure 3(b) and (c) , in another preferred embodiment the bottom inner supporting safety device has a cross section in the direction normal to the plane, P, wherein said cross section comprises a bottom transverse portion, P11a, extending transverse to the bottom edge, BotE, of the inner glazing and a first vertical portion, P12a, extending along the vertical axis, Z, having a top end and a bottom end, said vertical portion being connected to the bottom transverse portion, P11a and abutting the inner glazing internal surface and the inner frame.
As illustrated in Figure 3(d) , in the embodiment wherein the bottom edge, BotE, of the inner glazing (101) or of the outer glazing (10n) is stepped from the bottom edge, BotE of the outer glazing (10n) or of the inner glazing (101) respectively, it is further preferred that the cross section of the bottom inner supporting safety device (1181) further comprise a top transverse portion, P13a, extending transverse to the top end of the first vertical portion,P12a, and abutting the inner frame (11).
When carefully designed, the bottom inner supporting safety device can fulfil the retaining function. In this preferred embodiment, as illustrated in Figures 4 (a) to (c) , the inner retaining safety device (171) is any one of the bottom inner support safety device (1811) as described supra, wherein the cross section of said bottom inner support safety device further comprises a second vertical portion, P12b, extending along the vertical axis, Z, from the bottom transverse portion, P11a, and abutting the inner glazing external surface, IGes. This configuration can be preferred since it ensures both supporting and retaining functions within a single device and therefore is of particular use when the aesthetics of the window is of critical importance. Said second vertical portion can be slightly inclined within the flush tolerance thickness to allow for some glazing movement.
In one embodiment, the inner glazing of the handle free frameless sash can be a laminated glazing having an additional glazing laminated to the inner glazing external surface by at least one polymer interlayer to give the benefits of enhanced safety and acoustic performances. In such configurations, it can be contemplated that said second vertical portion, P12b, is embedded in the polymer interlayer between the additional glazing and inner glazing.
In an another embodiment, the inner glazing of the handle free frameless sash has a thickness (measured in the direction normal to the plane, P) equal to or greater than 8 mm, more preferably equal to or greater than 10 mm and more preferably equal to or greater than 12 mm, to give the benefit of enhanced acoustic performance. In such configuration, it can be contemplated that said second vertical portion, P12b, is anchored within a recess into the inner glazing.
It can be considered to reinforce even further the safety of the handle free frameless sash considering its weight depending on the thickness and dimensions of the glazings (101,10n). Therefore, in one embodiment of the present invention, the window can further comprise a second inner retaining safety device or a third inner retaining safety device.
The second inner retaining safety device (181n) is positioned on the lateral edge, LatE, of the inner glazing (101) for retaining the inner glazing external surface, IGes, to the inner frame (11). Therefore, in a preferred embodiment, said second inner retaining safety device (181n) has a cross section in the direction normal to the plane, P; wherein the cross section comprises :

(a) a lateral transverse portion, P21a, extending transverse to the inner glazing (101) lateral edge, LatE, and to the inner frame (11) , and
(b) a first longitudinal portion, P22a, extending along the longitudinal axis, X, from the lateral transverse portion, P21a, and abutting the inner glazing external surface, IGes.

The third retaining safety device is positioned on the top edge,TopE, of the inner glazing (101) for retaining the inner glazing external surface, IGes, to the inner frame (11). Therefore, in a preferred embodiment, said third inner retaining safety device has a cross section in the direction normal to the plane, P; wherein the cross section comprises :

(a) a top transverse portion, extending transverse to the top edge of the inner glazing and to the inner frame, and
(b) a first vertical portion extending along the vertical axis, Z, from the top transverse portion and abutting the inner glazing external surface.

The handle free frameless sash has by definition no outer frame. Therefore, its glassy corners are not covered and when the sash is in open position, users might bump into said sharp glassy corners. Therefore, to protect users from the sharp glassy corners, it is preferred that the handle free frameless sash of the present invention comprises a bottom inner supporting safety device (1811) positioned on the bottom edge, BotE, in the peripheral corner (151) of the inner glazing (101) connected to a second inner retaining safety device positioned on the lateral edge, LatE, in the corresponding peripheral corner (151) of the inner glazing (101), as depicted in Figure 5 . The bottom inner supporting safety device (1811) may be any one of the embodiments described above. Preferably, the cross section of the bottom inner supporting device further comprises the second vertical portion, P12b, to provide as well the retaining function.
In the preferred configuration wherein the bottom edge and the lateral edges of the inner glazing are stepped outwardly with respect to outer glazing, the second retaining safety device in addition to its safety function, can strengthens the support function of the bottom inner supporting safety device still ensuring the flush alignment between the handle free frameless sash and the fixed frame, and maintaining the mechanical performances of the handle free frameless sash. In such configuration as illustrated in Figure 5, the cross section of second inner retaining safety device further comprises

(a) a second longitudinal portion, P22b, extending along the longitudinal axis, X, having a top end and a bottom end, said bottom end of the longitudinal portion being connected to the lateral transverse portion, P21a,
(b) a top transverse portion, P23a, extending transverse to the top end of the second longitudinal portion, P22b, and abutting the inner frame.

The specific configuration, the dimensions, the choice of material for the retaining safety device(s) and the supporting safety device(s) will depend of the configuration (Size, thickness, weight) of the inner and outer glazings of the handle free frameless sash and therefore may be configured according to conventional calculations based upon the strength of material. In particular, a proper balance must be achieved between the minimum running length of each portion of the bottom inner supporting safety device along the corresponding edge required for the retaining and supporting functions and the maximal running length of the bottom transverse portion, P11a, and the second vertical portion, P12b, of the bottom inner supporting safety device along glazing external surfaces IGes, OGes, that is limited for aesthetics reasons.
In a preferred embodiment to take full advantage of the aesthetics opportunities the outer glazing of the frameless sash is further flush with the outer face of the fixed frame when the handle free frameless sash is in closed position. The flush alignment is then on both sides of the window facing the inner and outer environments respectively. In such configuration, the handle free frameless sash comprises the inner retaining safety device and preferably, an outer retaining safety device (172) for retaining the outer glazing external surface to the inner frame. The outer retaining safety device is positioned on the outer peripheral band and/or on the outer peripheral corner of the outer glazing, preferably on the outer peripheral corner, as illustrated in Figures 6 (a) to (d) . Such configuration provides especially suitable safety for users, while offering continuous smooth surfaces between the frameless sash and the fixed frame without any protrusion nor any significant recesses extend over both sides of the window facing inner and outer environments respectively and maintaining mechanical, thermal and tightness performances of the handle free frameless sash. In particular, the outer retaining safety devices by fixing the outer glazing to the inner frame, creates a mechanical bonding between the fixed frame and the outer glazing through the hardware.
All technical features and preferred technical features described in relation to the inner safety device (171) or to the bottom inner supporting safety device (1811) or to second inner retaining safety device (181n) or to the third retaining safety device can be applied correspondingly to an outer retaining safety device (172) or to a bottom outer supporting safety device (1821) or to a second outer retaining safety device or to a third outer retaining safety device.
Said outer retaining device may be combined with anyone of the inner retaining safety device and bottom inner supporting safety devices. The inner and outer retaining safety devices may be further connected for reinforcing the supporting and or retaining of the inner and outer glazing external faces to the inner frame. Preferred combinations are:

As illustrated in Figure 6 (a) , the handle free frameless sash comprises in anner and an outer retaining safety devices, preferably 2 screws (171, 172) passing through the inner glazing (101) and the outer glazing (10n) respectively, for fixing to the inner frame (11); or
As illustrated in Figure 6 (b) , the handle free frameless sash comprise a screw as the inner safety retaining device (171) and bottom inner supporting safety device acting as a further inner safety retaining device (1821), or
Figure 6 (c) , illustrates an embodiment with four safety devices: two screws as inner (171) and outer (172) retaining safety devices, a bottom outer supporting safety device (1821) and a bottom inner supporting safety device (1811), or
As illustrated in Figure 6 (d) , the handle free frameless sash comprise a screw as the inner safety retaining device (171) and a bottom inner supporting safety device (1811) connected to a bottom outer supporting safety device (1821) acting as a further inner safety retaining device.

The handle free frameless sash of the window of the present invention can comprise more than one inner retaining safety devices. It can comprise any combination of one or more inner retaining safety device, with one or more bottom inner supporting safety device, with one or more second inner retaining safety device, with one or more third inner retaining safety device, with one or more outer retaining safety device, with one or more bottom outer supporting safety device, with one or more second outer retaining safety device, with one or more third outer retaining safety device. As known by persons skilled in that art, the numbering and positioning of these devices on the edges of the handle free frameless sash of the window of the present invention will be carefully adapted for each window, depending on the technical characteristics (size, weight, ...) of the window and the location of use (external constraints).
As illustrated in Figure 7 , in a preferred embodiment and for higher thermal performance, the handle free frameless sash of the window of the present invention can further comprise one intermediate glazing (10i) to form a triple glazing. The handle free frameless sash will comprise an outer- (10n), intermediate- (10i), and inner-glazing (101) separated from one another by two gaps (121,12i), each gap being defined within a peripheral spacer (131, 13i). All technical features and preferred technical features described in relation to a double glazing can be applied correspondingly to the triple glazing.

Peripheral spacer

The handle free frameless sash of the present invention comprises at least an inner and an outer glazings (101, 101 i, 10n) separated by a gap (121, 12i) being defined within a peripheral spacer (131, 13i). Typically, the peripheral spacer is inserted between the glazing generally by means of butyl or silicone adhesive strips. The peripheral spacer can be hollow in order to be able to receive for example some drying material. Such peripheral spacer is then perforated to allow the drying material to trap water vapor that is coming in the gap of between the glazings of the handle free frameless sash. The peripheral spacer has typically a thickness equal to or greater than 6 mm. In general, the gap is filled with a gas which can be selected from the group consisting of air, dry air, argon (Ar), krypton (Kr), xenon (Xe), sulfur hexafluoride (SF6), carbon dioxide or a combination thereof. Said predetermined gas are effective for preventing heat transfer and/or may be used to reduce sound transmission. The peripheral spacer has a surrounding shape which spaces apart the glazings on their periphery. It can be made of one piece or can alternatively comprise a plurality of elements having their extremities abutted to form the surrounding shape. The peripheral spacer can be metallic, polymeric, a composite material reinforced by glass fibres or a mix of several of these materials. Use of warm-edge peripheral spacers, often made of plastics tightened and/or reinforced with a metallic foil, is preferred to reduce thermal fluxes at the periphery of the glazings what is indeed particularly critical for frameless glass sash since the periphery of the glazing is free of the outer frame.

Window Assembly

The frameless sash is coupled to a fixed frame, itself being sealingly coupled to a perimeter of a tunnel defined by an opening in a wall, with an inner face of the fixed frame facing an inner environment and an outer face of the fixed frame facing an outer environment, such that the inner environment is separated from the outer environment by the wall and the window when the frameless sash is in the closed position.
The window of the present invention is used for allowing light to pass through an opening in a wall. In many cases, a window can be opened to bring in fluid communication inner and outer environments separated from one another by said wall. To this purpose, the wall (30), which separates the inner environment from the outer environment, is provided with a through opening in the form of a tunnel defined by a tunnel perimeter. The fixed frame (20) is sealingly coupled to the tunnel perimeter, with the inner face of the fixed frame facing the inner environment and the outer face of the fixed frame facing the outer environment. When the frameless sash is in the closed position, the inner environment is separated from the outer environment by the window.
The wall (30) has a thickness, W30, measured normal to the plane, P. The thickness, W30, of the wall can be greater than or equal to the thickness, W20, of the fixed frame, W30 ≥ W20. In a preferred embodiment and for particularly aesthetic opportunities in the inner environment, the inner face of the fixed frame is flush with the wall at the inner environment. In an alternative embodiment, the outer face of the fixed frame is flush with the wall at the outer environment. Within the present invention and for particularly thin walls and for increasing the available interior volume of a living space for a given external floor area of a building, both inner and outer faces of the fixed frame are flush with the wall at the inner and outer environments. It is more preferred that that the inner glazing external surface is flush with the inner fame which is further flush with the wall at the inner environment. It is even more preferred that further to the alignment on the inner environment, the outer glazing external surface is flush with the outer fame which is further flush with the wall at the outer environment. In a particular preferred embodiment, the flush tolerance thickness, is at most +/- 2mm and preferably is 0 mm, resulting in the thickness of the wall, W30, being equal to the thickness of the fixed frame, W20, being equal to the thickness of the handle free frameless sash, W10, (W30 = W20 = W10).

Glazing

The glazing of the present invention can consist of a single glass pane or multiple glass panes. The single or multiple glass panes can be chosen among float clear, extra-clear or coloured glass. In particular and for aesthetic purposes, the glazing can be a decorative glazing such as a painted or etched or sand-blasted glazing or a combination thereof. The term "glass" is herein understood to mean any type of glass or equivalent transparent material, such as a mineral glass or an organic glass. The mineral glasses used may be irrespectively one or more known types of glass such as soda-lime-silica, aluminosilicate or borosilicate, crystalline and polycrystalline glasses. The glass pane can be obtained by a floating process, a drawing process, a rolling process or any other process known for manufacturing a glass pane starting from a molten glass composition. The glass pane can optionally be edge-ground. Edge grinding renders sharp edges into smooth edges which are much safer for people who could come into contact with a glass pane, in particular with the edge of frameless sash. Preferably, the glass pane is made of soda-lime-silica glass, aluminosilicate glass or borosilicate glass. More preferably and for reasons of lower production costs, the glass pane is made of a soda-lime-silica glass.
To maintain the mechanical performance and/or to further improve the safety of the handle free frameless sash, at least one glazing preferably consists of a single pre-stressed glass pane. For example, the inner glazing (101) and/or the outer glazing (10n) can be pre-stressed glass panes. In particular, when the inner retaining safety device and/or the outer retaining device is a screw and the glazing is a single glass pane, it is preferred that the glazing is a pre-stressed glass pane. A pre-stressed glass is a heat strengthened glass, a thermally toughened safety glass, or a chemically strengthened glass. Aluminosilicate-type glass compositions, such as for example those from the products range DragonTrail^® from Asahi Glass Co. or those from the products range Gorilla^® from Corning Inc., are also known to be suitable for chemical tempering.

In order to limit the overall weight and to adapt to the trend of building thinner walls observed in the building industry, the thickness of a glazing of a handle free frameless sash is preferably not more than 12 mm, preferably not more than 10 mm. The sum of thicknesses of all the glazings forming a handle free frameless sash according to the present invention is preferably at most 24 mm and more preferably at most 22 mm. Preferably, the composition for at least one of the glass panes of the frameless sash of the present invention comprises the following components in weight percentage, expressed with respect to the total weight of glass. Comp. A is an example of a first embodiment of glass composition, and Comp. B is an example of a soda-lime-silicate-type glass with a base glass matrix.

	Comp. A	Comp. B
SiO2	40 - 78%	60 - 78 wt%
Al2O3	0-18%	0 - 8 wt%, pref 0 - 6 wt%
B2O3	0-18%	0 - 4 wt%, pref 0 - 1 wt%
Na2O	0 - 20%	5 - 20 wt%, pref 10 - 20 wt%
CaO	0 - 15%	0 - 15 wt%, pref 5 - 15 wt%
MgO	0 - 10%	0 - 10 wt%, pref 0 - 8 wt%
K2O	0 - 10%	0 - 10 wt%
BaO	0-5%	0 - 5 wt%, pref 0 - 1 wt%.

Other preferred glass compositions for at least one of the glass panes of the frameless sash of the present invention comprise the following components in weight percentage, expressed with respect to the total weight of glass :

Comp. C	Comp. D	Comp. E
65 ≤ SiO₂ ≤ 78 wt%	60 ≤ SiO2 ≤ 78 %	65 ≤ SiO2 ≤ 78 wt%
5 ≤ Na₂O ≤ 20 wt%	5 ≤ Na2O ≤ 20 %	5 ≤Na2O ≤ 20 wt%
0 ≤ K₂O < 5 wt%	0.9 < K2O ≤ 12 %	1 ≤ K2O < 8 wt%
1 ≤ Al₂O₃ < 6 wt%, pref 3 < Al2O3 ≤ 5 %	4.9 ≤ Al2O3 ≤ 8 %	1 ≤ Al2O3 < 6 wt%
0 ≤ CaO < 4.5 wt%	0.4 < CaO < 2 %	2 ≤ CaO < 10 wt%
4 ≤ MgO ≤ 12 wt%	4 < MgO ≤ 12 %	0 ≤ MgO ≤ 8 wt%
MgO / (MgO + CaO) ≥ 0.5, pref. ≤ 0.88		K2O/(K2O+Na2O) : 0.1 - 0.7.
MgO / (MgO + CaO) < 1.

Other examples of base glass matrices for glass pane compositions suitable for the present invention are described in WO2015/150207 , WO2015/150403 WO2016/091672 , WO2016/169823 , and WO2018/001965 .
Within the present invention, a glass pane can comprise one or more layers such as low emissivity layers, heat ray reflection layers (solar control layers), anti-reflective layers, anti-fog layers. The one or more layers can be coated or applied as one or more films. At least one glazing (101, 10i,10n) preferably comprises a glass pane provided with a heat ray reflection layer or a low emissivity layer for improving the thermal insulating properties of the frameless sash.
Within the present invention and for improving the thermal insulating performance, as well as safety or acoustic performance, at least one of the glazing (101, 10i,10n) of the handle free frameless sash can be a multiple glazing. In particular, the multiple glazing can be selected among a vacuum insulating glazing (VIG) to yield particularly high insulating properties, or a laminated glazing to enhance safety and acoustic performances.
Within the present invention, at least one of the glazings (101, 10i, 10n) of the frameless sash can be an interactive glazing. The term "interactive glazing" is herein understood to mean a glazing integrating functional elements capable of responding to an external stimulation from the environment and/or from a user. For example, the interactive glazing can integrate functional elements including one or more of an electrochromic, thermochromic, or photochromic device, a photovoltaic device, a multimedia connection, an antenna, communication means, a TV set, a light source including a LED, a loudspeaker, a sensor including an irradiance-, temperature-, acoustic- sensor, and the like, or a combination thereof. The electrochromic device can be controlled manually, with a switch or a remote control, or it can be coupled to a sensor measuring the light irradiation and by a controller automatically controlling the voltage applied to the electrochromic device as a function of the level of irradiation.

The windows of the present invention are preferably highly energy-efficient. For this reason, it is preferred that the glazings of the handle free frameless sash (i.e., the transparent see-through area of the handle free frameless sash) have a thermal transmittance coefficient, Ug, of not more than 1.0 W / m² K, preferably of not more than 0.7 W / m² K, or even not more than 0.5 W / m² K.

REF	FEATURE
10	Handle free frameless sash
101	Inner glazing
10i	Intermediate glazing
10n	Outer glazing
11	Inner frame
121	Peripheral spacer
12i	Intermediate spacer
131	Gap adjacent to inner glazing 101
13i	Gap adjacent to glazing 10i
141	Peripheral band of the inner glazing
142	Peripheral band of the outer glazing
151	Peripheral corner of the inner glazing
152	Peripheral corner of the outer glazing
16	Structural resin
17	Interspace
171	Inner retaining safety device
172	Outer retaining safety device
1811	Bottom inner supporting safety device
181n	Second inner retaining safety device
1821	Bottom outer supporting safety device
P11a	Bottom transverse portion of the bottom inner supporting safety device
P12a	First vertical portion of the bottom inner supporting safety device
P13a	Top transverse portion of the bottom inner supporting safety device
P12b	Second vertical portion of the bottom inner supporting safety device
P21a	Lateral transverse portion of the second inner retaining safety device
P22a	First longitudinal portion of the second inner retaining safety device
P22b	Second longitudinal portion of the second inner retaining safety device
P23a	Top transverse portion of the second inner retaining safety device
20	Fixed frame
30	Wall
40	Sealing element
W10	Thickness of handle free frameless sash
W20	Thickness of fixed frame
W30	Thickness of the wall
BotE	Bottom edge of the inner or outer glazing
TopE	Top edge of the inner or outer glazing
LatE	Lateral edge of the inner or outer glazing
IGes	Inner glazing external surface
IGis	Inner glazing internal surface
OGes	Outer glazing external surface
OGis	Outer glazing internal surface

Claims

A window extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Z, comprising:
A. a handle free frameless sash (10) comprising:
(a) an inner glazing (101) having an inner glazing external surface, IGes, and an inner glazing internal surface, IGis, and

(b) an outer glazing (10n) having an outer glazing external surface, OGes, and an outer glazing internal surface, OGis,
wherein the inner and outer glazings:
• are free of an outer frame and free of a passing-through handle,

• are separated by a gap (121) defined within a peripheral spacer (131),

• have respectively a bottom edge, BotE, and a top edge, TopE, extending parallel to the longitudinal axis, X, and lateral edges, LatE extending parallel to the vertical axis, Z,

• have respectively inner and outer peripheral bands (141, 142) and inner and outer peripheral corners (151,152),

wherein the inner glazing external surface, IGes, is separated from the outer glazing external surface, OGes, by a sash thickness, W10, measured in the direction normal to the plane, P;

(c) an inner frame (11) positioned in a volume between the inner and outer glazings and between the peripheral spacer and the edges of the inner and outer glazings respectively;

B. a fixed frame (20) defining a frame opening and having an outer face and an inner face defining a frame thickness, W20, measured in the direction normal to the plane, P,
Characterised in that
• the inner face of the fixed frame is flush with the inner glazing external surface, IGes, when the handle free frameless sash is in closed position, and in that

• the handle free frameless sash comprises a inner retaining safety device (171) for retaining the inner glazing external surface to the inner frame.
The window according to claim 1 wherein the inner retaining safety device is positioned on an inner peripheral band and/or on an inner peripheral corner, preferably on an inner peripheral corner.
The window according to any one of the preceding claims, wherein the inner glazing further comprises a hole, preferably a chamfered hole, and wherein the inner retaining safety device is a fastening mean passing through the hole of the inner glass, preferably is a screw.
The window according to any one of the preceding claims, wherein the handle free frameless sash further comprises a bottom inner supporting safety device (1811) for supporting the bottom edge, BotE, of the inner glazing onto the inner frame.
The window according to claim 4, wherein the bottom inner supporting safety device has a cross section in the direction normal to the plane, P; wherein said cross section comprises a bottom transverse portion, P11a, extending transverse to the bottom edge, BotE, of the inner glazing, and abutting to the inner frame.
The window according to claim 4, wherein the bottom inner supporting safety device has a cross section in the direction normal to the plane, P, wherein said cross section comprises:
a) a bottom transverse portion, P11a, extending transverse to the bottom edge, BotE, of the inner glazing and,

b) a first vertical portion, P12a, extending along the vertical axis, Z, having a top end and a bottom end, said vertical portion being connected to the bottom transverse portion, P11 a and abutting the inner glazing internal surface and the inner frame.
The window according to any one of the preceding claims, wherein the bottom edge of the inner or outer glazing is stepped outwardly with respect to the bottom edge of the outer or inner glazing, preferably wherein the bottom edge of the inner glazing is stepped outwardly with respect to the bottom edge of the outer glazing, defining at least an interspace (17) extending between the inner and outer glazings from the inner frame to the bottom edges of the inner and outer glazings.
The window according to claim 7, wherein the cross section of the bottom inner supporting safety device further comprise a top transverse portion, P13a, extending transverse to the top end of the first vertical portion and abutting the inner frame.
A window according to any one to the claims 1-3, wherein the inner retaining safety device is the bottom inner support safety device (1811) as defined in anyone of the claims 4-8, wherein the cross section of said bottom inner support safety device further comprises a second vertical portion, P12b, extending along the vertical axis, Z, from the bottom transverse portion, P11a and abutting the inner glazing external surface.
The window according to any one of the preceding claims, wherein the handle free frameless sash further comprises a second inner retaining safety device (181n), said second inner retaining safety device having a cross section in the direction normal to the plane, P; wherein the cross section comprises :
(a) a lateral transverse portion, P21a, extending transverse to the lateral edge, LatE, of the inner glazing and to the inner frame, and

(b) a first longitudinal portion, P22a, extending along the longitudinal axis, X, from the lateral transverse portion, P21a, and abutting the inner glazing external surface.
The window according to claim 10, wherein the second retaining safety device is positioned on an inner peripheral corner and is connected to the bottom inner supporting safety device according to anyone of claims 4-9, preferably according to claim 9.
The window according to any one of the preceding claims, wherein the handle free frameless sash further comprises a third inner retaining safety device, said third inner retaining safety device having a cross section in the direction normal to the plane, P; wherein the cross section comprises :
(a) a top transverse portion, extending transverse to the top edge, TopE, of the inner glazing and abutting to the inner frame, and

(b) a first vertical portion extending along the vertical axis, Z, from the top transverse portion and abutting the inner glazing external surface.
The window according to any one of the preceding claims, wherein the handle free frameless sash is coupled to the fixed frame in one of the following manners:
(a) the handle free frameless sash is fixedly coupled to the fixed frame in the closed position, or

(b) the handle free frameless sash is movingly coupled to the fixed frame such that the handle free frameless sash can reversibly move with respect to the fixed frame from the closed position to an open position wherein the handle free frameless sash leaves open at least a portion of the frame opening.
The window according to any one of the preceding claims, wherein the handle free frameless sash further comprises one intermediate glazing (10i) forming a triple glazing unit formed by an inner (101), intermediate (10i ) and an outer glazing (10n) separated from one another by two gaps (131, 13i), each gap being defined within a peripheral spacer (121, 12i).
The window according to any one of the preceding claims, wherein when the handle free frameless sash is in the closed position, the outer face of the fixed frame is flush with the outer glazing external surface, OGes.
The window according to any one of the preceding claims, wherein the handle free frameless sash further comprises an outer retaining safety device (172) for retaining the outer glazing surface to the inner frame, wherein the outer retaining safety device is positioned on an outer peripheral band and/or on an outer peripheral corner of the outer glazing perimeter, preferably on an outer peripheral corner.
An assembly comprising a wall separating an inner environment from an outer environment and provided with a through opening in the form of a tunnel defined by a tunnel perimeter, and at least a window according to anyone of the preceding claims, wherein the wall has a thickness, W30, measured in the direction normal to the plane, P; which is greater than or equal to the thickness, W20, of the fixed frame, (W30 ≥ W20), and wherein the inner face of the fixed frame is flush with the wall and/or the outer face of the fixed frame is flush with the wall, preferably the inner face of the fixed frame is flush with the wall.