EP3740640B1

EP3740640B1 - Frameless casement with u-shaped profile

Info

Publication number: EP3740640B1
Application number: EP19700597.8A
Authority: EP
Inventors: Raphaël Alain BIR; Philippe BOUDOT; Nicolas CHORINE
Original assignee: AGC Glass Europe SA
Current assignee: AGC Glass Europe SA
Priority date: 2018-01-16
Filing date: 2019-01-15
Publication date: 2024-07-31
Anticipated expiration: 2039-01-15
Also published as: EP3740640A1; WO2019141670A1; EA202091680A1

Description

Technical Domain of the Invention

The present invention relates to a frameless glass casement with insulated glazing comprising an asymmetric outwardly open U-shaped profile.

Background of the Invention

The sufficient natural illumination of interior spaces, especially buildings, is one of key parameters for creating pleasant and healthy environment for people. The daylight is the most interesting source of such illumination and it is important to have some transparent parts in building envelopes, to bring this light to the interior of the building. Therefore, it is important to improve the Window to Wall Ratio (WWR). However, WWR is in general negatively influenced by new structures of windows and frames. Modern window frames provide usually better thermal insulation than traditional frame. Such insulated frames have larger sections than traditional windows and thus have again negative impact on natural illumination. The frame size is even more problematic for openable windows and facade segments, since the frame consists of two parts, a fixed frame and an openable casement or wing.
One solution to increase the WWR is to reduce the non-transparent part of the frame, by eliminating the openable casement frame and integrating window hardware into the Insulating Glass Unit (IGU). This technique of frameless glass casement, uses the structural capacity of the glazing to avoid the classical double frame structure of an openable window. Along with the improvement in transparency, it also improves window's aesthetics, by giving the window an appealing glassy look.
Since the openable casement frame has been removed or largely reduced, window hardware or fittings (being the metallic parts such as hinges, levers, sliding support, ...) which are, in traditional windows, positioned between the casement frame and fixed frame, and by means of which the casement can be opened or closed, must accordingly be positioned within the frameless glass casement.
The main challenge is hence to identify the right way to connect the frameless glass casement to the fixed frame to offer a complete frameless aspect or glassy look while keeping reasonable thermal insulation and tightness performances. Therefore, substantial attention has been brought to the development of specific profiles integrated into the frameless glass casements to provide the adequate space for the window hardware and to fulfill its significant mechanical function.
Such profile is for example disclosed in EP 2 402 540 describing a closure H-shaped profile element with different adhesives associated to different surfaces of the closure element. Caps are arranged between the closure element and the panes in a region in which the adhesives adjoin each other. In EP 1 020 605 , a support and/or edge termination element is described, which has a crosssection outwardly open, bounded by two equal-length legs, and undercut receiving groove for receiving fittings and/or functional parts such as in figure 1. In figure, 5 such support and/or edge termination element further comprises U-shaped receiving pockets on the sides of the support and/or edge termination element facing the insides of the glass panes, to receive drying material, and a nose on the frontal end, a receiving groove with a sealing lip and wherein the one leg of the profile is shorter than the other.
DE19509206A1 discloses an all-glass sash comprising an insulated glazing equipped with an outwardly open U-shaped profile.
There is still a need for the development of profiles having an improved design to fully support the weight of the frameless glass casement, especially in view of the increasing sizes and for triple glazing; accommodate window or door hardware, particularly commercially available window or door hardware while ensuring minimal thickness of the combination of the casement and the fixed frame.

Summary of the Invention

The present invention relates to a frameless glass casement with an insulated glass unit extending along a plane, P, defined by a horizontal axis, X, and a vertical axis, Z, wherein the frameless glass casement comprises peripheral edges including first and second lateral edges, extending parallel to the vertical axis, Z, and top and bottom edges extending parallel to the horizontal axis, X, and further comprising:

at least a first glass plate and a second glass plate comprising a first and second inner plate faces, respectively, and a first and second outer plate faces, respectively,
at least a spacer coupled to the first and second inner plate faces, recessed from the peripheral edges and defining an interspace extending between the first and second glass plates from the spacer to the peripheral edges,

wherein the interspace along one or more of the first and second lateral edges, and top and bottom edges comprises an outwardly open U-shaped profile positioned at least partially within the corresponding interspace, extending along a longitudinal axis, L, and having a cross section on a plane normal to the longitudinal axis, L,
said cross section has a width, W, and a height, H and comprises:
- a base element having a height, Hb, and a width, Wb,
- a first lateral wall protruding out of the base element in the direction of the height, Hb, comprising a first top edge and having a thickness, Tw1,
- a second lateral wall protruding out of the base element in the direction of the height, Hb, comprising a second top edge and having a thickness, Tw2,
- an inner profile volume, V, defined between the first lateral wall, the second lateral wall and the base element,
wherein all the widths and thicknesses are measured in the direction normal to the plane, P, and all the heights are measured normal to the widths,
wherein the thickness, Tw2, of the second lateral wall is at least 25% larger, preferably at least 50% larger, more preferably at least 75% larger than the thickness, Tw1, of the first lateral wall.

According to the invention, the base element comprises first and second shoulders jutting outwardly from the base in the direction of the width, and each being adjacent to the corresponding first and second lateral walls.

Brief description of drawings

Figure 1 shows a cross sectional view of the edge of a frameless glass casement according to one embodiment of the present invention illustrating the positioning of an outwardly open U-shaped profile. Out of convenience, the shape of the profile is simplified and does not represent the shoulders of the profile.
Figure 2 shows a cross sectional view of a simplified outwardly open U-shaped profile without shoulders (not according to the invention), illustrating the concepts of base element, lateral walls, inner profile volume and their main dimensions.
Figure 3 shows a cross sectional view of an outwardly open U-shaped profile according to an embodiment of the present invention.
Figure 4 shows a cross sectional view of a simplified outwardly open U-shaped profile without shoulders (not according to the invention), illustrating the concept of protrusions of the lateral walls.
Figure 5 shows a cross sectional view of an outwardly open U-shaped profile according to a further embodiment of the present invention.
Figure 6 shows a cross sectional view of the edge of a frameless glass casement illustrating the positioning of an outwardly open U-shaped profile in a triple glazing. Out of convenience, the shape of the profile is simplified and does not represent the shoulders of the profile.

Detailed description

Accordingly, it is an object of the present invention to provide a frameless glass casement arrangement with an insulating glass unit (IGU), having an outwardly open U-shaped profile which is especially suitable to accommodate commercially available window or door hardware, ensures a minimal thickness of the combination of the casement and the fixed frame (i.e. minimal thickness of the glass structure, the glass structure being the combination of the casement and the fixed frame) and fulfills its required function of supporting the weight of the frameless glass casement. It has been surprisingly found that an outwardly open U-shaped profile, comprising a base element and two lateral walls protruding out of the base element wherein one lateral wall is thicker than the other lateral wall provides adequacy to commercially available window hardware while maintaining the thickness of the glass structure as small as possible.
By casement, it is meant the fixed or openable component which is connected to the fixed frame through hardware means, and fills the opening defined by the static frame. The hardware means include all the devices, fittings, or assemblies, necessary to operate the window or door as intended. The casement is made of an infill panel, such as glass or glazing in case of a glass window or door arrangement, and generally a mobile frame, which is mounted around the edges of the infill panel.
By frameless glass casement, it is meant that the casement of the glass structure has a higher transparent surface than a standard one by elimination of some or all the frame elements of the casement. In standard doors or windows, fastening or fixing means are positioned between the casement frame and fixed frame. Such fastening or fixing means are doors or windows hardware. In frameless glass casement according to the present invention, fastening or fixing means are positioned between the glass plates allowing to eliminate frame parts of the casement. It means that the casement shape and volume is fully defined by the glass plates of the glazing. The present invention is not limited to any specific type of frameless glass casement. The frameless glass casement of the invention may be a fixed casement, or an openable frameless glass casement such as a tilt and turn casement, a sliding casement such as the lift-and-slide and tilt-and-slide variants.
The present invention relates to one frameless casement with an insulated glass unit (100) extending along a plane, P, defined by a horizontal axis, X, and a vertical axis, Z. The frameless casement comprises peripheral edges including first and second lateral edges, extending parallel to the vertical axis, Z, and top and bottom edges extending parallel to the horizontal axis, X.
As depicted in Figure 1 , the frameless glass casement with an insulated glass unit of the present invention comprises at least a first glass plate (10) and a second glass plate (20). The first and second glass plates comprise a first (12) and second (22) inner plate faces, respectively, and a first (13) and second (23) outer plate faces, respectively. The frameless glass casement at least a spacer (4) coupled to the first and second inner plate faces, recessed from the peripheral edges and defining an interspace (5) extending between the first and second glass plates from the spacer to the peripheral edges. The interspace along one or more of the first and second lateral edges, top and bottom edges comprises an outwardly open U-shaped profile (60) positioned at least partially within the corresponding interspace, extending along a longitudinal axis, L, and having a cross section on a plane normal to the longitudinal axis, L. Out of convenience, the U-shaped profile illustrated in Figure 1 is simplified and does not represent the shoulders jutting outwardly from the base.
As described herein, within the insulated glass unit of the frameless glass casement, the inner faces of the glass plates (12, 22) are meant to be the faces of the glass plates facing the interspace (5). In contrast, the outer faces of the glass plates (13, 23) are meant to be the faces of the glass plates facing the outside of the insulated glass unit.
In a preferred embodiment, the outwardly open U-shaped profile is positioned within a lateral edge, preferably the lateral edge that will be in contact with the corresponding lateral part of the fixed frame that comprises the necessary locking hardware elements. In a further preferred embodiment of the present invention, an outwardly open U-shaped profile will be further positioned within the top and bottom edges of the frameless glass casement. In an even more preferred embodiment of the present invention, the interspace along the first and second lateral edges, top and bottom edges comprises an outwardly open U-shaped profile.
The glass plates (10, 20) will be chosen among all flat glass technologies, among them: float clear, extra-clear or colored glass. The glass plates can be safety glass of following types: thermally or chemically tempered glass or laminated glass, which are known to the skilled people. The glass plates can optionally be edge-ground. Edge grinding renders sharp edges into smooth edges which are much safer for people who could come in contact with the casement, in particular with the edge of the casement. Other options, such as heat insulation with low-e coatings, solar control coatings, reinforced acoustic insulation with acoustic laminated glass are also compatible with the present concept to improve the performances of the window or door. Glass plates with electrochromic, thermochromic, photochromic or photovoltaic elements are also compatible with the present invention. The first and second glass plates of the frameless glass casement of the present invention can be of the same or of a different type. The glass plates of the frameless glass casement of the present invention can be of the same dimensions or of different dimensions and form thereby a stepped IGU. Having a stepped insulating glass is particularly advantageous to have a protection that prevents direct access of building occupants to the window or door hardware and opening/closing mechanisms what can be unsafe, especially for children. Step(s) can be on the whole periphery of the insulating glass as well as, on only a part of it. For tilt-and-turn hardware for instance, hardware mechanisms lie all around the casement, and therefore, all round the insulating glass. Thus, for tilt-and-turn hardware, step will preferably go all around the insulating glass: the insulating glass unit is a four- sides stepped unit (for rectangular or square shape). Double glazing units will be single- stepped, while triple glazing can be single- or double-stepped. Double-stepped means that the three glass plates are shifted compared to each other.
Painting parts of the surface of insulating glass unit is a well-known technique to hide unaesthetical elements located behind the glass. The opaque layer can be used to hide hardware or other window/door parts like tightness joints. Opaquer is the paint, less the window hardware and tightness elements are visible to the building occupants. Preferably, the paint will be located on an inner surface of the glazing, so that it is protected from direct external ageing and wear factors (rain, sun, abrasion...). More preferably it will extend from the edge of the glass to the level of the spacer. The paint can be of various types, organic or inorganic.
In a preferred embodiment of the present invention, the glass plates of the insulated glass unit of the frameless glass casement are tempered for users' safety. The use of tempered glass plates in the insulated glass unit of the frameless glass casement of the present invention is indeed advantageous since the glass casement is frameless and therefore has no peripheral protection, it is more likely prone to contacts and shocks linked to human activities inside or outside the building.
The insulated glass unit of the frameless glass casement of the present invention further comprises at least a spacer (4) coupled to the first and second inner plate faces, recessed from the peripheral edges and defining an interspace (5) extending between the first and second glass plates from the spacer to the peripheral edges. The spacer has consequently a surrounding shape which spaces apart the glass plates 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 spacer can be metallic, polymeric, a composite material reinforced by glass fibres or a mix of several of these materials. The spacer can be hollow in order to be able to receive for example some drying material. Such spacer is then perforated to allow the drying material to trap water vapor that is coming in the cavity of the IGU.
As is usual with insulated glazing, the spacer is inserted between the glass plates generally by means of butyl or silicone adhesive strips. Thereby, formed is an encompassing surrounding edge joint, such as is usual for insulated glazing, which is provided with a cordon of sealant. Thus, the cavity between the glass plates is sealed with respect to the exterior in a gas and moisture-sealed type manner. The cavity, as is known per se, can be filled with dry air or an insulating gas such as argon, krypton or mixtures thereof or it can be (partially) evacuated.
Use of warm-edge spacers, often made of plastics tightened and/or reinforced with a metallic foil, is preferred to reduce thermal fluxes at the periphery of the insulating glass what is indeed particularly critical for frameless glass casements since the periphery of the glazing is not embedded in a frame.
Figure 2 shows the cross section on a plane normal to the longitudinal axis, L, of a simplified outwardly open U-shaped profile (60) not falling in the scope of the appended claims, but illustrating the main elements of the profile (base elements, lateral walls and inner profile volume) and their dimensions. This cross section has a width, W, and a height, H and comprises:

a base element (63) having a height, Hb, and a width, Wb,
a first lateral wall (61) protruding out of the base element in the direction of the height, Hb, comprising a first top edge (61e) and having a thickness, Tw1,
a second lateral wall (62) protruding out of the base element in the direction of the height, Hb, comprising a second top edge (62e) and having a thickness, Tw2,
an inner profile volume, V, defined between the first lateral wall, the second lateral wall and the base element,

The closed end of the inner volume is the one being part of the base element.
The height, H, and the width, W, of the outwardly open U-shaped profile of the present invention are defined as the height and the width of the rectangle in which the profile is inscribed. The thickness of a lateral wall is defined as the value of the thickness measured at half the height, Hw1, Hw2, respectively.
The outwardly open U-shaped profile of the present invention having a cross section comprising first and second lateral walls with the thickness, Tw2, of the second lateral wall being at least 25% larger than the thickness, Tw1, of the first lateral wall; is hereinafter referred to as the "asymmetric U-shaped profile".
In frameless glass casements, the window or door hardware is therefore encompassed within the outwardly open U-shaped profile positioned within the interspace. The closing, opening and/or tilting of the frameless glass casement occurs via the interaction of hardware of the frameless glass casement to the hardware of the fixed frame. In order to reduce the cost of production of this rather recent frameless glass casement technology, the specific design of the outwardly open U-shaped profile according to the invention allows to use commercially available window or door hardware rather than developing dedicated door or window hardware. Moreover, it has been found that the asymmetric outwardly open U-shaped profile within the frameless glass casement of the present invention ensures support for the weight of the frameless glass casement while minimizing the total thickness of the glass structure. The U-shaped profile has a cavity suitable to accommodate the part of the hardware dedicated to the openable casement and to have it properly aligned with the part of the hardware dedicated to the fixed frame. It ensures to have a minimal casement-fixed frame thickness, i.e. minimal glass structure thickness, the glass structure being hence the combination of the casement and fixed frame. A minimal casement-fixed frame thickness advantageously reduces the space constraints in the building.
In one embodiment, the thickness, Tw2, of the second lateral wall, is at least 1.25 mm, preferably at least 2.5 mm and at most 10 mm, preferably at most 5.5 mm. In another embodiment, the thickness, Tw1, of the first lateral wall, is at least 1 mm, preferably at least 2 mm and at most 4 mm, preferably at most 3 mm. These embodiments are of particular interest in the case of fixed and tilt- and-turn frameless glass casements.
The base element of the cross section of the asymmetric U-shaped profile comprises a bottom edge and a top edge. The width of the base element, Wb, is measured at half the height of the base element, Hb. In a preferred embodiment, the width, Wb, of base element is smaller than the width, W, of the asymmetric U-shaped profile, as illustrated in Figure 3 . More preferably, the width of the base element, Wb, represents at most 90%, preferably at most 80%, more preferably at most 70% of the width, W, of the outwardly open U-shaped profile. For applications in fixed or tilt-and-turn frameless glass casements, width, Wb, of the base element of the outwardly open U-shaped profile is preferably at most 29 mm, more preferably at most 26 mm and even more preferably at most 23 mm. Figure 3 illustrates an embodiment according to the invention wherein the base element comprises first and second shoulders (61s, 62s) jutting outwardly from the base in the direction of the width, W, each shoulder being adjacent to the corresponding first and second lateral walls.
In Figure 4 , each of the first and second lateral walls of the cross section of a simplified outwardly open U-shaped profile comprises a protrusion (61p, 62p) jutting outwardly of the inner profile volume V in the direction of the width, W, and each being adjacent to the corresponding first and second top edges (61e, 62e). The simplified U-shaped profile of Figure 4 does not fall in the scope of the appended claims, but illustrates the concept of said protrusions.
In a further preferred embodiment, the protrusion of each of the first and second lateral walls of the cross section of the outwardly open U-shaped profile comprises a recess (61r, 62r) adjacent to the first and second top edges (61e, 62e). The recesses are open on the inner profile volume, V, and on the corresponding first and second top edges (61e, 62e), as shown in Figure 5 .
It has been surprisingly found that such protrusions (61p, 62p) and/or recesses (61r, 62r) bring the following advantageous technical benefits:

partial protection and thereby increased sustainability, of the bonding mean (18) when used to fix the asymmetric U-shape profile within the interspace, in particular, against squeeze and/or dirt;
easier alignment of the asymmetric U-shaped within the interspace (5), and in particular with the peripheral edge of the corresponding glass plate;

Thereby, it has been found that the most preferred asymmetric U-shaped profile of the present invention combines a smaller base element (63) with the protrusions (61p, 62p) and recesses (61r, 62r) at the top edges of the first and second lateral walls as illustrated by Figure 5 . It provides surprising adequacy to commercially available window hardware, and support to the weight of the frameless casement, while maintaining the thickness of the glass structure as small as possible.
The height of the first lateral wall, Hw1, is typically larger than 8mm, preferably larger than 10mm. The height of the first lateral wall is typically smaller than 20mm, preferably smaller than 15mm. In a preferred embodiment, the height of the first lateral wall, Hw1, is equal to the height of the second lateral wall, Hw2. This embodiment is of particular interest when recesses are present in the protrusions of the lateral walls.
In an alternative embodiment, the base element of the cross section of the outwardly U-shaped profile, forms a hollow profile for cost reduction and/or thermal conductivity improvement.
The asymmetric U-shaped profile is positioned at least partially within the corresponding interspace. In a preferred embodiment such as for the fixed and tilt-and-turn frameless glass casements, the asymmetric U-shaped profile is flush with or recessed from the corresponding peripheral edges of the frameless glass casement.
In a preferred embodiment of the present invention, the frameless glass casement closes an opening in a partition defining an interior space and an exterior space and is positioned such that the second lateral wall of the asymmetric U-shaped profile and therefore the corresponding second glass plate, is facing the interior space.
According to another aspect of the invention, the asymmetric U-shaped profile of the present invention runs all along the periphery edges as one single and continuous framing structure or as strongly connected segments forming a continuous framing structure. In this way, the asymmetric U-shaped profile does not only serve as a receptacle for the window or door hardware; it also has a significant structural function. Having a continuous profile framing around the IGU enables to transfer loads applied on one point or on one profile segment to the whole framing. Best example is the self - weight of the casement when it is opened in turn position: the continuous framing structure enables to transfer the loads applied to the bottom segment to the other segments of the profile, and therefore to the hinges that are usually positioned on a side segment of the profile framing. Situation is similar for racking loads, that is the loads applied in a direction parallel to the plan of the casement.
In case that profile is made of several segments, segment lengths and shapes can be various. For instance (possibilities are not limited to the ones given hereafter), for a square or rectangular shaped casement, profile framing can be made of four straight segments connected in the four corners, or even two L segments connected in two corners. Profile segments are connected by at least one mean adapted to ensure durable structural connection. Examples of suitable structural connection means are self-tapping screw or connector pieces, adhesive bonding with structural glue like silicone or structural tape like VHB tape, welding, soldering, brazing, or even a combination of them.
The asymmetric U-shaped profile is usually made of metal, wood, polymers, composites with a polymer matrix.
Preferred materials to make the profile are thin walled stainless steel, hardwood, wood polymer composites, stiff polymers, fibres reinforced polymers. More preferred are fibres reinforced polymers.
Hardwood can be oak. Examples of wood polymer composites are 60 wood /40 Polypropylene (PP) or 60 wood /40 High Density Polyethylene (HDPE). Suitable stiff polymers are PolyEtherEtherKetone (PEEK), Polyamides (PA), Polyphenylene Sulfide (PPS), Polybutylene Terephtalate (PBT). Examples of fibres reinforced polymers are those reinforced with glass fibres, carbon fibres or aramid fibres and having a matrix selected from PEEK, PPS, PBT, PA, polyesters, thermoset resins. Preferred fibres reinforced polymers are those reinforced with glass fibres, more preferred are reinforced with glass fibres and have a matrix polyesters or thermoset resins matrix, most preferred have a glass fibres content of at least 50 wt%.
Preferably the outwardly open U-shaped profile is bonded to both the first and second glass plates. Suitable types of bonding means (18) are sealants and/or double side adhesive tapes, preferably those demonstrating good adherence, with or without primer, on both glass and profile surfaces, suitable mechanical properties, and suitable chemical resistance, especially to UVs, water and temperature. Examples of sealants are silicone, modified silicone, and polyurethane. One example of double-sided adhesive tape is VHB^® tape. If a combination of sealant(s) and tape(s) is used, chemical compatibility between the components must be ensured.
The insulating glass unit (IGU), as a basis of the casement, has a well- known double seal configuration, made of a first seal placed between the spacer and the glass plates, typically butyl strips, and a secondary seal encompassing the spacer, which sustains mechanical loads linked to high and low pressure cycles in the IGU. In designing and producing frameless casements, it is very advantageous for the fixing of the asymmetric U-shaped profile within the IGU, to use the same material used for the secondary seal, sealing the spacer to the first and second glass plates rather than using a third material. In this case, the secondary seal is chosen amongst the sealants described supra as suitable to bond the U-shaped profile to the glass plates. It reduces the risk of chemical incompatibility. Furthermore, such material offers very beneficial properties of good adherence, chemical resistance, moisture resistance and hence sustainability. However, this material needs significant thickness to withstand shear stress due to thermal changes sustained by the frameless glass casement during its lifetime. On the other hand, it is wished to have a minimal glass structure thickness to reduce the space constraints in the building. Therefore, this required thickness can be an issue when such material is used to bond the U-shaped profile with the glass plates. It has been found that in the frameless glass casement of the present invention, the width of base element of the asymmetric U-shaped profile, Wb, can be advantageously reduced in comparison to the width of the U-shaped profile, W, (as illustrated in figure 3). It allows fulfilling the secondary sealant thickness requirements while ensuring a minimal glass structure thickness and still keeping the width of the asymmetric U-shaped profile, W, sufficiently wide to accommodate the hardware. Furthermore, the secondary sealant can advantageously be avoided along the first and second lateral walls. In this case, a double-sided adhesive tape may be applied along the lateral walls. Suitable double-sided adhesive tapes are those described supra as suitable to bond the U-shaped profile to the glass plates.
According to one aspect of the invention, the frameless glass casement is characterized in that the insulating glass unit is a double glazing. According to another aspect of the invention, the frameless glass casement is characterized in that the insulating glass unit is a triple glazing.
Triple glazing unit is usually more thermally insulating than a double glazing unit with Ug values (U value of the glazing) that can easily reach 0,6 W/m<2>K or even 0,5 W/m<2>K.
The frameless glass casement comprising a triple insulating glass unit comprises a first glass plate (10), a second glass plate (20) and a third glass plate (15). The third glass plate can be positioned either in the interspace (5) between the first and second glass plates or externally of the IGU formed by the first and second glass plates, parallely facing the outer face of the first or second glass plate (13, 23).
In a variant of this embodiment, the IGU is a stepped triple IGU (single-stepped or double-stepped). This variant is of particular interest for fixed and tilt-and-turn frameless glass casements.
In a preferred embodiment, the triple glazing frameless glass casement is characterized in that it comprises two spacers that are positioned at the same level inside the IGU. Resulting aesthetics is much more pleasant to building occupants.
According to a further aspect of the invention, the frameless door or window casement arrangement is characterized in that the middle glass pane of the triple glazing is a thin glass plate with thickness lower than 2mm. Reduction of weight of windows has become an important care, especially for window installers. Indeed, reducing the weight allows to use less people to install a window or to use less hindering equipment to mount the window. A way to reduce window weight is to use thinner glass. The thin glass plate can be a thermally or chemically tempered glass, preferably a chemically tempered glass.
In the embodiment where the third glass plate is positioned in the interspace, the peripheral edges of the third glass plate are preferably recessed from the peripheral edges of the first and second glass plates and further recessed from the asymmetric U-shaped profile. This configuration is of particular interest for a lift-and-slide frameless glass casements.

Figure 6 illustrates a frameless glass casement with an insulated glass unit having triple glazing. The frameless glass casement comprises a first glass plate (10), a second glass plate (20) and an asymmetric U-shaped profile (60) positioned between the inner plates faces (12, 22) of the first and second glass plates (10, 20). Out of convenience, the U-shaped profile illustrated in Figure 6 is simplified and does not represent the shoulders jutting outwardly from the base. The third glass plate (15) has a peripheral edge (16) recessed from the top edge of the asymmetric U-shaped profile (60). The spacer (4) of the frameless glass casement is formed by a first spacer (4a) positioned between the first glass plate and the third glass plate and a second spacer (4b) positioned between the third glass plate and the second glass plate. The interspace (5) extends between the first and second inner plate face plate (12, 22), from the first spacer (4a), the third peripheral edge, the second spacer (4b) to the first and second peripheral edges (11,21). The illustrated embodiment further comprises an opaque layer (17) covering a peripheral zone of the first and second inner face plates (12, 22), extending from the first and second bottom edges to above the spacers (4, 4b). The interspace (5) is filled with a secondary sealant (18).

Ref.#	Feature
100	Frameless glass casement
10	First glass plate
11	First peripheral edge
12	First inner plate face
13	First outer plate face
20	Second glass plate
21	Second peripheral edge
22	Second inner plate face
23	Second outer plate face
4	Spacer
4a	First spacer
4b	Second spacer
5	Interspace
60	Asymmetric outwardly open U-shaped profile
61	First lateral wall
61e	First top edge
61p	Protrusion of the first lateral wall
61r	Recess within the protrusion of the first lateral wall
62	Second lateral wall
62e	Second top edge
62p	Protrusion of the second lateral wall
62r	Recess within the protrusion of the second lateral wall
63	Base element
61s	First shoulder of the base element
62s	Second shoulder of the base element
H	Height of the cross section of the outwardly open U-shaped profile
W	Height of the cross section of the outwardly open U-shaped profile
Hb	Height of the base element
Ww	Height of the base element
Hw1	Height of the first lateral wall
Hw2	Height of the second lateral wall
Tw1	Thickness of the first lateral wall
Tw2	Thickness of the second lateral wall
V	Inner volume of the outwardly open U-shaped profile
15	Third glass plate
16	Third peripheral edge
17	Opaque layer
18	Secondary sealant

Claims

A frameless glass casement with an insulated glass unit (100) extending along a plane, P, defined by a horizontal axis, X, and a vertical axis, Z, wherein the frameless glass casement comprises peripheral edges including first and second lateral edges, extending parallel to the vertical axis, Z, and top and bottom edges extending parallel to the horizontal axis, X, and further comprising:
- at least a first glass plate (10) and a second glass plate (20) comprising a first (12) and second (22) inner plate faces, respectively, and a first (13) and second (23) outer plate faces, respectively,

- at least a spacer (4) coupled to the first and second inner plate faces, recessed from the peripheral edges and defining an interspace (5) extending between the first and second glass plates from the spacer to the peripheral edges,
wherein the interspace along one or more of the first and second lateral edges, and top and bottom edges comprises an outwardly open U-shaped profile (60) positioned at least partially within the corresponding interspace, extending along a longitudinal axis, L, and having a cross section on a plane normal to the longitudinal axis, L,

said cross section has a width, W, and a height, H and comprises:
• a base element (63) having a height, Hb, and a width, Wb,

• a first lateral wall (61) protruding out of the base element in the direction of the height, Hb, comprising a first top edge (61e) and having a thickness, Tw1,

• a second lateral wall (62) protruding out of the base element in the direction of the height, Hb, comprising a second top edge (62e) and having a thickness, Tw2,

• an inner profile volume, V, defined between the first lateral wall, the second lateral wall and the base element,

wherein all the widths and thicknesses are measured in the direction normal to the plane, P, and all the heights are measured normal to the widths,

wherein the thickness, Tw2, of the second lateral wall is at least 25% larger, preferably at least 50% larger, more preferably at least 75% larger than the thickness, Tw1, of the first lateral wall, characterized in that the base element comprises first and second shoulders (61s, 62s) jutting outwardly from the base in the direction of the width, W, and each being adjacent to the corresponding first and second lateral walls.
A frameless glass casement according to any one of the claim 1, wherein the thickness, Tw2, of the second lateral wall, is at least 1.25 mm, preferably at least 2.5 mm and at most 10 mm, preferably at most 5.5 mm and/or wherein the thickness, Tw1, of the first lateral wall, is at least 1 mm, preferably at least 2 mm and at most 4 mm, preferably at most 3 mm.
A frameless glass casement according to any one of preceding claims, wherein width, Wb, of the base element is smaller than the width, W, of the outwardly open U-shaped profile.
A frameless glass casement according to claim 3, wherein the width of the base element, Wb, represents at most 90%, preferably at most 80%, more preferably at most 70% of the width, W, of the outwardly open U-shaped profile.
A frameless glass casement according to any one of preceding claims, wherein the interspace along the first and second lateral edges, top and bottom edges comprise an outwardly open U-shaped profile.
A frameless glass casement according to any one of the preceding claims, wherein each of the first and second lateral walls of the cross section of the outwardly open U-shaped profile comprises a protrusion (61p, 62p) jutting outwardly of the inner profile volume V in the direction of the width, W, and each being adjacent to the corresponding first and second top edges (61e, 62e).
A frameless glass casement according to claim 6 wherein the protrusion of each of the first and second lateral walls of the cross section of the outwardly open U-shaped profile comprises a recess (61r, 62r) open on the inner profile volume, V, and on the corresponding first and second top edges (61e, 62e).
A frameless glass casement according to any one of preceding claims, wherein the first and second lateral walls have a height, Hw1, and Hw2, measured normal to the thickness Tw1 and Tw2, respectively from a top edge of the base element to the corresponding first and second top edges; wherein the height of the first lateral wall, Hw1, is equal to the height of the second lateral wall, Hw2.
A frameless glass casement according to any one of preceding claims, wherein the base element forms a hollow profile.
A frameless glass casement according to any one of preceding claims, wherein the outwardly open U-shaped profile is made of material selected from the groups consisting of metal, wood, polymers, composites with a polymer matrix.
A frameless glass casement according to any one of preceding claims, wherein the outwardly open U-shaped profile is bonded to the first and second inner plate faces with bonding means (18) selected from sealants and/or double side adhesive tapes, preferably wherein the sealant is made of material selected from the group consisting of silicone, modified silicone and/or polyurethane.
An opening in a partition defining an interior space and an exterior space and being closed by a frameless glass casement according to any of the preceding claims, wherein the second lateral wall and the corresponding second glass plate are facing the interior space.