Laminated glazing panel

A laminated glazing panel comprising first and second sheets of glazing material joined by an interlayer structure comprising a first sheet of adhesive interlayer material is described. Inboard of a peripheral edge of the first sheet of glazing material, the first sheet of glazing material has a hole therein. The laminated glazing panel further comprises a glazing fitting secured thereto, the glazing fitting comprising a head portion and an attachment feature. The head portion is positioned in the hole such that a first surface thereof faces the first sheet of adhesive interlayer material. Some of the first sheet of adhesive interlayer material is in the hole and is operatively associated with the first attachment feature thereby attaching the glazing fitting to the first sheet of adhesive interlayer material. Suitable glazing fittings and methods of making such laminated glazing panels are also described.

BACKGROUND OF THE INVENTION

The present invention relates to a laminated glazing panel, to a glazing fitting for securing to a laminated glazing and to a method for making a laminated glazing panel.

Frameless glazing systems for buildings are well known. Buildings incorporating a structural glass façade or curtain wall incorporating the Pilkington PLANAR™ glazing system are one such example. This type of structural glazing system comprises a plurality of glazing panels ranging typically in size between 1 m×1 m and 2.5 m×4.5 m or larger, for example 3m×6 m, wherein each glazing panel is independently secured to an adjacent support structure via mechanical mountings and fittings. Each glazing panel usually comprises a sheet of glass that has been toughened and may be laminated to meet specific legislative requirements. Each glazing panel may be double or triple glazed to provide increased environmental performance.

In such frameless glazing systems, each glazing panel usually has a number of holes drilled through it, which may be straight or countersunk holes, for securing a glazing fitting thereto. For a rectangular glazing panel, the fixing holes or bores are usually in the vicinity of each corner and a glazing fitting is secured to the glazing panel via each hole. Depending upon the size of the glazing panel, additional holes may be located at other positions around the periphery of the panel.

Frameless glazing systems are known comprising glazing panels having two sheets of glass joined by an interlayer sheet where the glazing fitting is secured to the glazing panel via a hole that passes through both sheets of glass, or via a hole that passes through only one of the sheets of glass. Such glazing panels are sold by Nippon Sheet Glass Co. and are known as Pilkington Planar™ Integral, see https://www.pilkington.com/en-gb/uk/architects/types-of-glass/structural-glazing/sy stem-components/glass/laminated-safety-glass/pilkington-planar-intergral.

Another known laminated glazing panel for use in a frameless glazing system is described in WO2006/121440A1. The glazing panel described in has internal and an external glass element bonded together by a polymer interlayer. A capped nut is embedded in the polymer interlayer and a bolt comprising a head and a threaded end is engaged with the embedded capped nut and passes through a circular fixing hole formed through the internal glass element. Such laminated glazing panels are also described in WO96/22443A1.

Embedding a capped nut in a polymer interlayer requires an additional cutting step, because in addition to cutting a hole in a glass sheet, a hole must also be made in the polymer interlayer so that the capped nut may be embedded therein. This additional process step can increase assembly time and production costs. Furthermore, it is necessary to carefully align the embedded capped nut with the holes in the glass sheet to allow access thereto.

There is a need for an alternative laminated glazing that at least partially overcomes the aforementioned problems.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides from a first aspect a laminated glazing panel comprising: a first sheet of glazing material joined to a second sheet of glazing material by an interlayer structure comprising at least a first sheet of adhesive interlayer material, the first sheet of glazing material having a first major surface and an opposing second major surface; the laminated glazing panel being arranged such that the first major surface of the first sheet of glazing material faces the interlayer structure; there being a hole in the first sheet of glazing material, the hole having a wall between the first and second major surfaces of the first sheet of glazing material and being inboard of a peripheral edge of the first sheet of glazing material; the laminated glazing panel further comprising a glazing fitting secured thereto, the glazing fitting comprising: a head portion and an attachment feature, the head portion having a first surface and an opposing second surface, the head portion being positioned in the hole in the first sheet of glazing material such that the first surface thereof faces the first sheet of adhesive interlayer material; wherein some of the first sheet of adhesive interlayer material is in the hole in the first sheet of glazing material and is operatively associated with the first attachment feature thereby attaching the glazing fitting to the first sheet of adhesive interlayer material.

By operatively associating some of the first sheet of adhesive interlayer material with the first attachment feature, the glazing fitting remains attached to the first sheet of adhesive interlayer material even if the first sheet of glazing material is removed or the rigidity thereof is reduced, for example by breaking. This is particularly advantageous when the laminated glazing panel is used as a pane in a point fixed glazing system. In such a glazing system the glazing fitting may be secured to a suitable support structure, and in the event of breakage of the first sheet of glazing material the glazing fitting remains attached to the first sheet of adhesive interlayer material because some of the adhesive interlayer material of the first sheet of adhesive interlayer material is in the hole in the first sheet of glazing material and operatively associated with the first attachment feature. This prevents the second sheet of glazing material from falling away from the glazing system because the second sheet of glazing material is joined to the first sheet of adhesive interlayer material, and some of the first sheet of adhesive interlayer material is operatively associated with the first attachment feature of the head portion so that the glazing fitting is attached to the first sheet of adhesive interlayer material, the glazing fitting also being secured to the suitable support structure. This is particularly important when the second sheet of glazing material is an external facing pane in a building, because upon breaking the first sheet of glazing material, which would be an internal facing pane, the external pane remains secured to the support structure via the glazing fitting, instead of falling away outside of the building.

During a lamination process to make the laminated glazing panel, the first sheet of adhesive interlayer material softens and is able to flow into the hole in the first sheet of glazing panel. The glazing fitting is configured with at least one attachment feature such that some of the first sheet of adhesive interlayer material operatively associates with the attachment feature to attach the glazing fitting to the first sheet of adhesive interlayer material.

Preferably the second sheet of glazing material does not have any holes therein.

Preferably the first surface of the head portion is flat, or substantially flat.

Preferably the first surface of the head portion is aligned with the first major surface of the first sheet of glazing material.

The first surface of the head portion has an outer perimeter. Preferably the outer perimeter of the first surface of the head portion is circular, or substantially circular. Other shapes for the outer perimeter of the first surface of the head portion are possible, for example oval, triangular, quadrilateral, pentagonal, hexagonal etc.

Preferably the first and second surfaces of the head portion are arranged to provide a countersunk head portion. That is, it is preferred that the head portion is a countersunk head portion.

The hole in the first sheet of glazing material has a first opening in the first major surface of the first sheet of glazing material in communication with a second opening in the second major surface of the first sheet of glazing material. The wall of the hole connects the first opening in the first major surface of the first sheet of glazing material to the second opening in the first sheet of glazing material. That is, the wall of the hole is between the first opening in the first major surface of the first sheet of glazing material and the second opening in the second major surface of the first sheet of glazing material.

In some embodiments the head portion has at least a first channel extending between the first and second surfaces thereof, the first channel having a first end and a second end; the first channel communicating with an entrance hole in the first surface of the head portion at the first end and with an exit hole in the second surface of the head portion at the second end, and wherein some of the first sheet of adhesive interlayer material is in the first channel That is, some of the first sheet of adhesive interlayer material extends through the entrance hole in first surface of the head portion into the first channel in the head portion of the glazing fitting. In these embodiments the head portion is provided with an attachment feature being the first channel.

Preferably the first channel is configured such that between the first and second ends thereof some of the first sheet of adhesive interlayer material operatively communicates with the first channel to attach the glazing fitting to the first sheet of adhesive interlayer material.

Preferably some of the first sheet of adhesive interlayer material extends through the exit hole in the second surface of the head portion.

Preferably some of the first sheet of adhesive interlayer material extends through the exit hole in the second surface of the head portion to contact the second surface of the head portion.

Preferably the second surface of the head portion comprises a groove portion in communication with the exit hole of the first channel.

Preferably the groove portion extends around the second surface of the head portion.

Preferably the groove portion extends in a ring around the second surface of the head portion.

Preferably some of the first sheet of adhesive interlayer material is in the groove portion and operatively associated therewith to attach the glazing fitting to the first sheet of adhesive interlayer material.

In some embodiments the head portion is configured such that at least part of the head portion is spaced apart from the wall of the hole by a first space, and the second surface of the head portion is configured to provide at least one attachment feature, wherein some of the first sheet of adhesive interlayer material is in the first space between the wall of the hole and the head portion and some of the first sheet of adhesive interlayer material is operatively associated with the at least one attachment feature of the second surface of the head portion.

In such embodiments, at least a part of the outer perimeter of the first surface of the head portion is spaced apart from the first opening in the first major surface of the first sheet of glazing material so that some of the first sheet of adhesive interlayer material can flow into the first space during a lamination process used to make the laminated glazing panel to operatively associate with the at least one attachment feature of the second surface of the head portion.

Preferably the at least one attachment feature of the second surface of the head portion comprises at least a first recess in the second surface of the head portion and some of the first sheet of adhesive interlayer material is in at least a portion of the first recess in the second surface of the head portion.

Preferably the first recess in the second surface of the head portion extends around the second surface of the head portion.

Preferably the first recess in the second surface of the head portion extends around the second surface of the head portion in a ring, which may or may not be a closed ring.

Preferably the first recess in the second surface of the head portion is adjacent to the outer perimeter of the first surface of the head portion.

Preferably the first recess in the second surface of the head portion comprises a stepped region and/or an undercut region.

In some embodiments the head portion has at least a first channel extending between the first and second surfaces thereof, the first channel having a first end and a second end; the first channel communicating with an entrance hole in the first surface of the head portion at the first end, and with an exit hole in the second surface of the head portion at the second end, and some of the first sheet of adhesive interlayer material is in the first channel; and the head portion is configured such that at least part of the head portion is spaced apart from the wall of the hole by a first space, and the second surface of the head portion is configured to provide at least one attachment feature, wherein some of the first sheet of adhesive interlayer material is in the first space between the wall of the hole and the head portion and some of the first sheet of adhesive interlayer material is operatively associated with the at least one attachment feature of the second surface of the head portion.

In some embodiments the glazing fitting further comprises a washer configured to fit in the hole in the first sheet of glazing material and configured such that the head portion nests therein, the washer having an internal surface and an opposing external surface; the internal surface of the washer facing the second surface of the head portion and the external surface of the washer being configured to contact at least a portion of the wall of the hole, the external surface of the washer also being configured to provide at least one attachment feature; wherein the external surface of the washer is spaced apart from the wall of the hole in the first sheet of glazing material by at least a first space, and wherein some of the first sheet of adhesive interlayer material is in the first space between the wall of the hole and the external surface of the washer; and wherein some of the first sheet of adhesive interlayer material is operatively associated with the at least one attachment feature of the external surface of the washer.

Preferably the washer is a cup washer.

Preferably the external surface of the washer is configured to nest in the hole.

Preferably the external wall of the washer is configured such that a contact portion of the external surface of the washer contacts at least a portion of the wall of the hole.

The external surface of the washer and the internal surface of the washer are spaced apart to define a thickness of the washer.

Preferably the washer has a first minor surface at one end thereof and a second minor surface at the opposite end thereof.

Preferably the first minor surface of the washer is flat, or substantially flat.

Preferably the first minor surface of the washer is aligned with the first surface of the head portion and/or the first major surface of the first sheet of glazing material.

Preferably the second minor surface of the washer is flat, or substantially flat.

The external surface of the washer intersects with the first minor surface of the washer to define an outer edge of the washer.

Preferably the attachment feature of the external surface of the washer comprises a first recess in the external surface of the washer. It is preferred that the first recess in the second surface of the washer extends around the external surface of the washer, preferably in a ring, which may or may not be a closed ring. It is also preferred that the first recess in the external surface of the washer be adjacent to an outer edge of the washer.

Preferably the first recess in the external surface of the washer is at least partially filled with some of the first sheet of adhesive interlayer material.

Preferably the first recess in the external surface of the washer comprises a stepped region and/or an undercut region.

Preferably the external surface of the washer comprises a second recess, the second recess being spaced apart from the first recess preferably by a portion of the external wall of the washer that is in contact with at least a portion of the wall of the hole, the second recess in the external surface of the washer also being an attachment feature of the external surface of the washer.

Preferably the second recess in the external surface of the washer extends around the external surface of the washer, preferably in a ring.

Preferably the second recess in the external surface of the washer is in communication with the first recess in the external surface of the washer by at least one pathway in a portion of the external surface of the washer, preferably a portion of the external surface of the washer in contact with at least a portion of the wall of the hole.

Preferably the second recess in the external surface of the washer comprises a stepped region and/or an undercut region.

Preferably the second recess in the external surface of the washer is at least partially filled with some of the first sheet of adhesive interlayer material.

In some embodiments the head portion has at least a first channel extending between the first and second surfaces thereof, the first channel having a first end and a second end; the first channel communicating with an entrance hole in the first surface of the head portion at the first end, and with an exit hole in the second surface of the head portion at the second end, and some of the first sheet of adhesive interlayer material extends through the entrance hole in first surface of the head portion into the first channel in the head portion of the glazing fitting; the glazing fitting also comprising a washer configured to fit in the hole and configured for the head portion to nest therein, the washer having an internal surface and an opposing external surface, the internal surface of the washer facing the second surface of the head portion, at least one of the second surface of the head portion and the internal surface of the washer being configured to define a cavity between the internal surface of the washer and the second surface of the head portion for containing some of the first sheet of adhesive interlayer material from the exit hole, the cavity being in communication with the exit hole of the first channel.

In these embodiments the cavity is between the washer and the head portion and the head portion is between the cavity and the first sheet of adhesive interlayer material.

Preferably the second surface of the head portion comprises a groove portion in communication with the exit hole, wherein the cavity is formed between the groove portion and the internal surface of the washer.

Preferably the second surface of the head portion comprises a groove portion that extends around the second surface of the head portion, the groove portion being in communication with the exit hole, wherein the cavity is formed between the groove portion and the internal surface of the washer.

Preferably the internal surface of the washer comprises a groove portion opposite the exit hole, wherein the cavity is formed between the groove portion in the internal surface of the washer and the second surface of the head portion.

Preferably some of the first sheet of adhesive interlayer material is in the cavity and operatively associated therewith to attach the glazing fitting to the first sheet of glazing material.

Preferably the washer is a cup washer.

In some embodiments the glazing fitting further comprises a washer configured to fit in the hole in the first sheet of glazing material and configured such that the head portion nests therein, the washer having an internal surface and an opposing external surface; the internal surface of the washer facing the second surface of the head portion and the external surface of the washer being configured to contact at least a portion of the wall of the hole, the external surface of the washer also being configured to provide at least one attachment feature; wherein the external surface of the washer is spaced apart from the wall of the hole in the first sheet of glazing material by at least a first space, and wherein some of the first sheet of adhesive interlayer material is in the first space between the wall of the hole and the external surface of the washer and some of the first sheet of adhesive interlayer material is operatively associated with the at least one attachment feature of the external surface of the washer; and the head portion has at least a first channel extending between the first and second surfaces thereof, the first channel having a first end and a second end; the first channel communicating with an entrance hole in the first surface of the head portion at the first end, and with an exit hole in the second surface of the head portion at the second end, and some of the first sheet of adhesive interlayer material extends through the entrance hole in first surface of the head portion into the first channel in the head portion of the glazing fitting.

Preferably the washer is a cup washer.

Embodiments having a head portion comprising a first channel extending between the first and second surfaces thereof have other preferable features.

Preferably the head portion has two, or three, or four or more channels extending between the first and second surfaces of the head portion, each respective channel having a respective first end and a respective second end, each respective channel communicating with a respective entrance hole in the first surface of the head portion at the respective first end and with a respective exit hole in the second surface of the head portion at the respective second end.

Preferably at least one other channel between the first and second surfaces of the head portion has some of the first sheet of adhesive interlayer material extending therethrough to attach the glazing fitting to the first sheet of adhesive interlayer material.

Preferably the glazing fitting comprises a washer configured to fit in the hole and configured for the head portion to nest therein, the washer having an internal surface and an opposing external surface, the internal surface of the washer facing the second surface of the head portion to define a cavity therewith for containing a portion of the first sheet of adhesive interlayer material from the exit hole, the cavity being in communication with the exit hole of the first channel and at least one of the other channels in the head portion.

In some embodiments the glazing fitting comprises a stem portion, the stem portion extending away from the head portion and beyond the second major surface of the first sheet of glazing material.

Preferably the stem portion is cylindrical having a length and a radius and a first axis along the length.

Preferably the stem portion is integrally formed with the head portion. In such embodiments the stem portion integrally formed with the head portion is usually referred to as bolt in the art.

Preferably the stem portion is made from a stainless steel.

Preferably the stem portion is made from the same material as the head portion.

Preferably a mechanical fastener is attached to the stem portion and the glazing fitting is clamped to first sheet of glazing material between the mechanical fastener and the head portion.

Preferably the stem portion comprises a threaded portion and a mechanical fastener is screwed onto the threaded portion.

In some embodiments where the glazing fitting comprises a washer configured to fit in the hole and configured for the head portion to nest therein, the washer having an internal surface and an opposing external surface, the internal surface of the washer facing the second surface of the head portion to define a cavity therewith for containing a portion of the first sheet of adhesive interlayer material from the exit hole, the cavity being in communication with the exit hole of the first channel, and wherein the glazing fitting comprises a stem portion, the stem portion extending away from the head portion and beyond the second major surface of the first sheet of glazing material, the washer has a hole therein and the stem portion extends through the hole in the washer.

In embodiments wherein the glazing fitting comprises a washer and a stem portion, the stem portion extends through a second opening of the washer.

Other embodiments of the first aspect of the present invention have other preferable features.

Preferably the glazing fitting is attached to the first sheet of adhesive interlayer material and clamped to the first sheet of glazing material, more preferably the glazing fitting is attached to the first sheet of adhesive interlayer material by some of the first sheet of adhesive interlayer material extending into the hole in the first sheet of glazing material to operatively associate with the attachment feature and the glazing fitting is clamped to the first sheet of glazing material.

Preferably the head portion of the glazing fitting comprises a countersunk portion.

Preferably the first surface of the head portion is aligned with the first major surface of the first sheet of glazing material.

Preferably the head portion is made from a stainless steel.

Preferably the first sheet of adhesive interlayer material comprises an ionomer polymer, polyvinyl butyral (PVB), acoustic modified PVB, a copolymer of ethylene such as ethylene vinyl acetate (EVA), polyurethane (PU), polycarbonate, poly vinyl chloride (PVC) or a copolymer of ethylene and methacrylic acid.

Preferably the first and/or second sheet of glazing material comprises a sheet of glass, in particular a sheet of float glass.

Preferably the first and/or second sheet of glazing material comprises a sheet of soda-lime-silicate glass. Preferably the soda-lime-silicate glass has a composition comprising (by weight), SiO269-74%; Al2O30-3%; Na2O 10-16%; K2O 0-5%; MgO 0-6%; CaO 5-14%; SO3 0-2% and Fe2O30.005-2%.

Preferably the first and/or second sheet of glazing material is thermally toughened glass or chemically toughened glass.

Preferably the first sheet of glazing material has a thickness between 4 mm and 25 mm, more preferably between 6 mm and 20 mm.

Preferably the second sheet of glazing material has a thickness between 4 mm and 25 mm, more preferably between 6 mm and 20 mm.

Preferably the first sheet of adhesive interlayer material has thickness between 0.3 mm and 5 mm, more preferably between 0.38 mm and 1 mm.

When present, preferably the washer is made from aluminium.

The present invention also provides from a second aspect a glazing fitting for a laminated glazing panel, the laminated glazing panel comprising first and second sheets of glazing material joined together by at least a first sheet of adhesive interlayer material, the glazing fitting being configured for securing to a hole in the first sheet of glazing material, the hole extending between opposing major surfaces of the first sheet of glazing material; the glazing fitting comprising: a head portion having a first surface for facing the first sheet of adhesive interlayer material and an opposing second surface; and an attachment feature for operatively associating with some of the first sheet of adhesive interlayer material during a lamination process for making the laminated glazing panel to attach the glazing fitting to the first sheet of adhesive interlayer material following the lamination process.

Preferably the attachment feature comprises at least a first channel extending through the head portion communicating at a first end with an entrance hole in the first surface of the head portion and at a second end with an exit hole in the second surface of the head portion.

Preferably the second surface of the head portion comprises a groove portion in communication with the exit hole.

Preferably second surface of the head portion comprises a groove portion extending around the second surface of the head portion, preferably in a ring.

Preferably the second surface of the head portion is configured to provide at least one attachment feature.

Preferably the at least one attachment feature of the second surface of the head portion comprises a recess in the second surface of the head portion

Preferably the recess in the second surface of the head portion extends around the entire second surface of the head portion.

Preferably the recess in the second surface of the head portion is adjacent to an outer periphery of the first surface of the head portion.

Preferably the recess in the second surface of the head portion comprises a stepped region and/or an undercut region.

In some embodiments the glazing fitting further comprises a washer configured to fit in the hole in the first sheet of glazing material and configured for the head portion to nest therein, the washer having an internal surface and an opposing external surface; the internal surface of the washer for facing the second surface of the head portion and the external surface of the washer being configured to contact at least a portion of the wall of the hole in the first sheet of glazing material, and wherein the external surface of the washer is configured to provide at least one attachment feature.

Preferably the attachment feature of the external surface of the washer comprises a first recess in the external surface of the washer.

Preferably the first recess in the second surface of the washer extends around the external surface of the washer, preferably in a ring, which may or may not be a closed ring.

Preferably the first recess in the external surface of the washer is adjacent to an outer edge of the washer.

Preferably the first recess in the external surface of the washer comprises a stepped region and/or an undercut region.

Preferably the external surface of the washer comprises a second recess, the second recess being spaced apart from the first recess preferably by a portion of the external wall of the washer.

Preferably the portion of the external wall of the washer between the first and second recesses is configured for contacting the wall of the hole in the first sheet of glazing material.

Preferably the second recess in the external surface of the washer extends around the external surface of the washer, preferably in a ring.

Preferably the second recess in the external surface of the washer is in communication with the first recess in the external surface of the washer by at least one pathway in the portion of the external surface of the washer between the first and second recesses in the external surface of the washer.

Preferably the second recess in the external surface of the washer comprises a stepped region and/or an undercut region.

Preferably the washer is a cup washer.

Preferably the attachment feature comprises at least a first channel extending through the head portion communicating at a first end with an entrance hole in the first surface of the head portion and at a second end with an exit hole in the second surface of the head portion and the internal surface of the washer is configured to define a cavity between the internal surface of the washer and the second surface of the head portion when the head portion is nested in the washer, the cavity being in communication with the exit hole of the first channel

In some embodiments the glazing fitting comprises a stem portion extending away from the second surface of the head portion.

Preferably the stem portion is cylindrical having a length and a radius and a first axis along the length.

Preferably the stem portion comprises a threaded portion for engagement with a suitable mechanical fastener.

Preferably the stem portion is integrally formed with the head portion.

Preferably the stem portion is substantially cylindrical.

Preferably the stem portion is made from a stainless steel.

In some embodiments the head portion of the glazing fitting has two, or three, or four or more than four channels extending between the first and second surfaces of the head portion, each respective channel having a respective first end and a respective second end, each respective channel communicating with a respective entrance hole in the first surface of the head portion at the respective first end, and with a respective exit hole in the second surface of the head portion at the respective second end of the channel Other embodiments of the second aspect of the present invention have other preferable features.

Preferably the head portion is made from a stainless steel.

Preferably the head portion has two channels extending through the head portion, each channel respectively communicating at a first end with a respective entrance hole in the first surface of the head portion and at a second end with a respective exit hole in the second surface of the head portion, wherein when view in plan elevation, the two channels are on opposite sides of the head portion.

Preferably the head portion has four channels extending through the head portion, each channel respectively communicating at a first end with a respective entrance hole in the first surface of the head portion and at a second end with a respective exit hole in the second surface of the head portion, wherein when viewed in plan elevation, the four channels are equally spaced around the head portion.

Preferably the head portion has four channels extending through the head portion, each channel respectively communicating at a first end with a respective entrance hole in the first surface of the head portion and at a second end with a respective exit hole in the second surface of the head portion, and the glazing fitting comprises a stem portion extending away from the second surface of the head portion, wherein when viewed along a longitudinal axis of the stem portion, the four channels are equally spaced around the stem portion.

Preferably the head portion is a countersunk head portion.

Preferably the glazing fitting comprises a mechanical fastener for attaching to a stem portion extending from the head portion.

The present invention also provides from a third aspect a method for making a laminated glazing panel comprising the steps: (i) providing a first sheet of glazing material having at least a first hole extending between a first and a second major surface thereof; (ii) providing a glazing fitting according to the second aspect of the present invention; (iii) positioning the head portion of the glazing fitting in the hole such that the first surface of the head portion faces in the direction of the first major surface of the first sheet of glazing material; (iv) providing a first sheet of adhesive interlayer material; (v) positioning the first sheet of adhesive interlayer material on the first major surface of the first sheet of glazing material to cover the first surface of the head portion; (vi) laminating the first sheet of adhesive interlayer material to the first sheet of glazing material using suitable lamination conditions; wherein during step (vi) the head portion is configured such that some of the first sheet of adhesive interlayer material flows into the hole to operatively associate with the attachment feature to attach the glazing fitting to the first sheet of adhesive interlayer material.

Preferably following step (v) a second sheet of glazing material is positioned on the first sheet of adhesive interlayer material such that following step (vi) the laminated glazing panel produced has the first sheet of adhesive interlayer material between the first and second sheets of glazing material. Preferably the second sheet of glazing material has no holes therein.

Preferably the first sheet of adhesive interlayer material comprises an ionomer polymer, polyvinyl butyral (PVB), acoustic modified PVB, a copolymer of ethylene such as ethylene vinyl acetate (EVA), polyurethane (PU), polycarbonate, poly vinyl chloride (PVC) or a copolymer of ethylene and methacrylic acid.

Preferably the first second sheet of glazing material comprises a sheet of glass, in particular a sheet of float glass.

Preferably the first sheet of glazing material comprises a sheet of soda-lime-silicate glass. Preferably the soda-lime-silicate glass has a composition comprising (by weight), SiO269-74%; Al2O30-3%; Na2O 10-16%; K2O 0-5%; MgO 0-6%; CaO 5-14%; SO30-2% and Fe2O30.005-2%.

Preferably the first sheet of glazing material is thermally toughened glass or chemically toughened glass.

Preferably the first sheet of glazing material has a thickness between 4 mm and 25 mm, more preferably between 6 mm and 20 mm.

Preferably the first sheet of adhesive interlayer material has thickness between 0.3 mm and 5 mm, more preferably between 0.38 mm and 1 mm.

The first sheet of adhesive interlayer material may comprise one or more sheets of adhesive interlayer material.

When present, the second sheet of glazing material preferably has a thickness between 4 mm and 25 mm, more preferably between 6 mm and 20 mm.

When the glazing fitting comprises a stem portion extending away from the head portion, at step (iii) the stem portion passes through an opening in the second major surface of the first sheet of glazing material.

DETAILED DESCRIPTION OF THE INVENTION

FIG.1shows a schematic cross-sectional view of a bolt1and a cup washer11that are part of a glazing fitting in accordance with an aspect of the present invention.FIG.2is a plan view of the bolt shown inFIG.1.FIG.3is a plan view of the cup washer shown inFIG.1.FIG.4is a plan view of the bolt and cup washer ofFIG.1where the bolt is in the cup washer.

With reference toFIGS.1-4, the bolt1is made of stainless steel and has a countersunk head portion3and a stem portion5integrally formed therewith. In this embodiment the stem portion5is threaded for engagement with a suitably sized nut (not shown) or other similar mechanical fastener. The stem portion5is substantially cylindrical having a length and a radius.

The countersunk head portion3has a flat first surface4and an opposing second surface6tapered towards the stem portion5. Passing through the countersunk head portion3are four straight channels9a,9b,9cand9d(9dnot shown inFIG.1). Each channel9a,9b,9c,9dis normal to the first surface4and communicates at one end with a respective entrance hole in the first surface4, and at the other end with a respective exit hole in the second surface6. For example, the channel9bhas an entrance hole9b′ in the first surface4and an exit hole9b″ in the second surface6.

The first surface4intersects with the second surface6to define an edge8of the countersunk head portion3. The first surface3has a circular outer perimeter defined by the edge8.

The second surface6has a groove7therein in communication with the exit holes of the channels9a,9b,9cand9d. The groove is substantially semi-circular in profile and has been formed by milling around the countersunk head portion. For example, a conventional countersunk bolt may have the groove7formed in the head portion by milling, followed by drilling the channels9a,9b,9c,9dto communicate with the first surface4and the groove7in the second surface6.

The cup washer11is a washer having an opening19at one end thereof (and another opening at the opposite end, not labelled). The cup washer11has an external wall13and an internal wall15. The internal wall15is suitably configured such that the countersunk head portion3can nest therein i.e. by moving the bolt1in the direction of arrow10. The separation of the external wall13and the internal wall15defines the thickness of the cup washer. At one end the cup washer11has a minor surface14. The minor surface14is flat.

The cup washer11has a collar portion17having an inner wall18that defines the periphery of the opening19in the cup washer. The opening19is suitably sized such that the stem portion5of the bolt1can pass therethrough.

In use, the cup washer is usually in direct contact with the glazing material, for example soda-lime-silicate glass, so the cup washer11is typically made from a softer material than the bolt1. It is preferred that the bolt1is made from stainless steel and the cup washer11is made from aluminium.

When viewed in the direction of arrow2i.e. in plan view, the countersunk head portion3is circular and the groove7is concentric with the outer edge8of the head washer and inboard thereof. Exit holes9a″,9b″,9c″ and9d″ of respective channels9a,9b,9c,9dcan be seen in communication with the groove7. The edge8can be seen to be circular and defines the outer perimeter of the first surface4.

The view of the bolt1inFIG.1is essentially a cross-section through the line j-j′ ofFIG.2, with the inclusion of the position for channel9b.

As more clearly seen in the plan view ofFIG.3(i.e. viewed in the direction of arrow2), the cup washer11has a circular opening19therein defined by the inner wall18of the collar portion17. The cup washer has a circular periphery and the internal surface15is configured such that the countersunk head portion3of the bolt1can nest therein.

FIG.4shows a plan view when the bolt1is inserted through the opening19in the cup washer11. The stem portion5extends through the hole19and is configured to be a sliding fit with the inner wall18of the collar portion17.

FIG.5shows in more detail a portion of a cross-sectional view ofFIG.4along the line m-m′, again with the inclusion of the position for channel9b.

With the countersunk head portion3nested in the cup washer11, the stem portion5can be seen to extend through the opening19in the cup washer11.

The internal wall15of the cup washer11defines a cavity23with the groove7in the second surface of the countersunk head portion3. The cavity23extends around the countersunk head portion3because the groove7extends inboard of the edge8of the countersunk head portion3and the internal wall15nests with the countersunk head portion3.

The channel9ais in fluid communication with the cavity23such that fluid material may flow into the cavity23via the channel9ai.e. in the direction of arrow9aa.

The channel9bis also in fluid communication with the cavity23. Not shown inFIG.5are the channels9c,9d, which are also in fluid communication with the cavity23.

FIGS.6-10are used to describe how a laminated glazing panel according to the present invention is made.

FIG.6shows a schematic cross-sectional representation of a bolt1and cup washer11as described with reference toFIGS.1-5prior to being secured to a sheet of glass30.

Firstly, a first sheet of glass30is provided having a suitable countersunk hole32therein configured for the cup washer11to nest therein. The first sheet of glass30has a first major surface34and an opposing second major surface36. The countersunk hole32has a wall33in between the first and second major surfaces34,36of the first sheet of glass30. The countersunk hole32has a first opening in first major surface34and a second opening in the second major surface36. The first opening in the first major surface34is circular and the second opening in the second major surface36is also circular but has a smaller diameter than the first opening.

In plan view, the first sheet of glass30has a rectangular periphery and the countersunk hole32is inboard of the periphery i.e. inboard of the peripheral edge of the first sheet of glass30.

FIG.7shows a plan view of a corner portion of the first sheet of glass30. The other corner portions of the first sheet of glass30may have similar countersunk holes therein.

Again, with reference toFIG.6, the cup washer11is first inserted into the countersunk hole32by moving in the direction of arrow37. The external surface13of the cup washer11is configured to nest in the countersunk hole32. Next, the bolt1is moved in the direction of arrow39so that the stem portion5passes through the opening19in the cup washer11.

A schematic cross-sectional view of the cup washer11nesting in the countersunk hole32with the bolt1in the cup washer11is shown inFIG.8. The head portion3of the bolt1nests in the cup washer11and the stem portion5extends through the opening19in the cup washer and extends beyond the second major surface36of the first sheet of glass30. The minor surface14of the cup washer11and the first surface4of the head portion3are aligned with the first major surface34of the first sheet of glass30.

The bolt1may be clamped to the first sheet of glass30prior to lamination by using a suitable mechanical fastener engaged with the stem portion5. InFIG.8, an inner flange63is screwed onto the threaded stem portion5. A suitable washer62may first be positioned on the stem portion5to prevent the inner flange63from directly contacting the second major surface36of the first sheet of glass30. The washer62is flat and made of aluminium. The inner flange63is made of stainless steel. The inner flange63may be tightened to a desired torque to clamp the bolt1to the first sheet of glass30prior to a suitable lamination process.

To make a laminated glazing panel in accordance with an embodiment of the present inventions, next a sheet of ionomer polymer40is positioned on the first major surface34of the first sheet of glass30by moving the sheet of ionomer polymer in the direction of arrow42.

The sheet of ionomer polymer40has a first major surface44and a second opposing major surface46and is sized to be congruently stacked with the first sheet of glass30i.e. the edges of the first sheet of glass30are aligned with the edges of the sheet of ionomer polymer40when the sheet of ionomer polymer40is positioned on the first sheet of glass30.

The sheet of ionomer polymer40has no holes therein and covers the first surface4of the head portion3of the bolt1.

Next a second sheet of glass50is positioned on the sheet of ionomer polymer40by moving in the direction of arrow52. The second sheet of glass50has a first major surface54and a second opposing major surface56. The second sheet of glass52is sized to be coextensive with the sheet of ionomer polymer40such that when the second sheet of glass50is on the sheet of ionomer polymer40, the second sheet of glass50is congruently stacked therewith. The second sheet of glass50does not have any holes therein, in particular there is no hole in the second sheet of glass directly opposite the countersunk hole32in the first sheet of glass30. In use, the second sheet of glass50would be an external pane, and the first sheet of glass30would be an internal pane.

A schematic cross-sectional representation of a portion of the congruent stack described above prior to lamination is shown inFIG.9. InFIG.9, the arrangement of the bolt1in the cup washer11is as described with reference toFIG.5. The bolt1is shown not clamped to the first sheet of glass30prior to lamination, but the bolt1may be clamped to the first sheet of glass30prior to lamination, as discussed above i.e. by using a mechanical fastener screwed onto the stem portion5of the bolt1.

As can be seen fromFIG.9, the channels9a,9band9cface the sheet of ionomer polymer40. Channel9d(not shown) also faces the sheet of ionomer polymer40.

Prior to lamination, the channels9a,9b,9c,9dand the cavity23are empty (other than containing the surrounding atmosphere) i.e. the channels9a,9b,9c,9ddo not contain any ionomer polymer40from the sheet of ionomer polymer40and instead contain air.

In order to produce a laminated glazing panel in accordance with the present invention, the unlaminated congruent stack of components is laminated at a suitable temperature and pressure to join the first sheet of glass30to the second sheet of glass50by the sheet of ionomer polymer40.

During the lamination process, the unlaminated stack of components may be placed in a vacuum bag or the like to evacuate air from between the components of the unlaminated stack.

During the lamination process, the sheet of ionomer polymer40softens and under the applied pressure is able to flow into the channels9a,9b,9c,9dand through into the cavity23. It is preferred to completely fill the channels9a,9b,9c,9dand the cavity23with some of the ionomer polymer material that flows from the sheet of ionomer polymer40during the lamination process. This is illustrated inFIG.10which shows a schematic cross-sectional representation of a portion of the laminated glazing panel60following the lamination process.

InFIG.10the channels9a,9band9cand the cavity23are shaded grey to indicate that some ionomer polymer material from the sheet of ionomer material40is contained therein, and preferably fills the channels9a,9band9c(and9d) and the cavity23. In this way some of the ionomer polymer sheet operatively associates with the channels9a,9b,9c,9dand the cavity23so that the bolt1is attached to the sheet of ionomer material.

For a sheet of ionomer polymer such as SentryGlas Plus® available from DuPont, a temperature of around 140° C. and a pressure of 5-15 bar was found acceptable to cause the adhesive interlayer material to flow through the channels in the countersunk head portion, into the cavity and around the countersunk head portion.

FIG.11shows in more detail the laminated glazing panel60and additional components that may be part of the glazing fitting.FIG.11also shows how additional mechanical fasteners elements may be secured to the glazing fitting to allow the laminated glazing panel to be attached to a building or the like.

As described above, the laminated glazing panel60has a bolt1and cup washer11secured in the hole in the sheet of glass30because the sheet of glass30is joined to the second sheet of glass50by the sheet of ionomer polymer40.

Either prior to lamination, or thereafter, an inner flange63is screwed onto the threaded stem portion5of the bolt1. The inner flange63is made of stainless steel and to avoid direct contact with the second major surface36of the sheet of glass30an aluminium washer62is first inserted over the stem portion5before the inner flange63engages therewith.

The inner flange63has an inner threaded section64for screwing onto the threaded stem portion5, and an outer threaded section66for engagement with addition mechanical fasteners.

As discussed above, it is preferred to screw the inner flange63onto the threaded stem portion5to a desired torque prior to the lamination process.

When the inner flange63is screwed onto the threaded stem portion5, an outer flange67may be attached thereto. The outer flange67has a body portion68having an opening69therein with threaded walls for screwing onto the outer threaded section66of the inner flange63. The outer flange67also has integrally formed therewith a mounting portion70. The outer flange67is also made of stainless steel.

The mounting portion70may be used to attach the laminated glazing panel60to a bracket73attached to a support structure in a building. The laminated glazing panel60may be a pane in a façade or other frameless glazing system.

The mounting portion70passes through an opening in the bracket73(which is made from stainless steel). Stainless steel washers72,74are positioned either side of the opening in the bracket73and the mounting portion70passes through the washers72,74.

The mounting portion70has a threaded portion71for engagement with a suitable nut76to secure the outer flange67to the bracket (and hence the laminated glazing panel60to the bracket when the outer flange67is connected to the inner flange63).

In use, the second sheet of glass50is an external pane (i.e. facing the outside of the building in which the laminated glazing panel60is installed) and the first sheet of glass30is an inner pane. In the event of breakage of the first sheet of glass30, the mechanical integrity thereof becomes compromised, and without using the glazing fitting of the present invention, may result in the second sheet of glass50(with the sheet of ionomer polymer laminated thereto) becoming detached from the laminated glazing panel60.

By using a glazing fitting in accordance with the present invention, the bolt1is attached to the sheet of ionomer polymer40, which is laminated to the second sheet of glass50. The second sheet of glass50is therefore prevented from falling away from the building because the bolt1is attached to the sheet of ionomer polymer40, which is laminated to the second sheet of glass50.

The laminated glazing panel60attached to the bracket73is shown inFIG.12. In this figure the ionomer material in the channels and the cavity is shown to illustrate how the ionomer material from the sheet of ionomer polymer has flowed into the channels and cavity of the glazing fitting to attach the glazing fitting to the sheet of ionomer polymer.

If the first sheet of glass30is removed from the glazing panel shown inFIG.12, the sheet of ionomer40with second sheet of glass joined thereto will remain secured to the bracket73via the glazing fitting and mechanical fasteners.

FIG.13illustrates a schematic cross-sectional view of another laminated glazing panel60′ in accordance with the present invention incorporating a different glazing fitting. Like parts are labelled with previously used reference numerals.

In this example, instead of using a bolt with an integrally form stem portion as previously described, the glazing fitting comprises a countersunk head portion3′ that does not have a stem portion integrally formed therewith. Otherwise, the countersunk head portion is configured in essentially the same way as the countersunk head portion3of the bolt1described with reference toFIG.1.

The countersunk head portion3′ may be positioned in a cup washer11as previously described, and the laminated glazing panel may be produced as discussed above. However, in this example a stem portion5′ is attached to the countersunk head portion after lamination.

With reference toFIG.13, the countersunk head portion3′ has a threaded inner wall for engagement with a threaded stem portion5′. Other connection means may be used to connect the stem portion5′ to the countersunk head portion3′. Once the stem portion5′ is screwed to the countersunk head portion3′ (by moving in the direction of arrow80), the laminated glazing panel may be mounted to a bracket in a building as described with reference toFIGS.11and12.

FIG.14shows an isometric representation of another cup washer111useful in a glazing fitting in accordance with the present invention. The bolt1in this figure is the same as previously described with reference toFIGS.1-4.

FIG.15shows a cross-sectional representation of the cup washer111taken alone the line p-p′ ofFIG.14.

In this embodiment the cup washer111has a conical internal surface115configured for the head portion3of the bolt1to nest therein (when the bolt1is inserted into the cup washer111such that the stem5passes through opening hole119). In this respect, the internal surface of the cup washer111is configured in the same way as the internal surface of the cup washer11. However, in contrast to the external surface13of the cup washer11(which is essentially parallel to the inner surface15), the external surface113of the cup washer111is has a step-like structure to provide the external surface of the cup washer111with attachment features, as shall be described hereinafter.

With reference toFIGS.14and15, the cup washer111has a flat minor surface114at one end thereof. The external surface113of the cup washer111has a first minor surface117perpendicular to the minor surface114. The minor surface114intersects with the first minor surface117of the external surface to define an outer edge118of the cup washer111. The outer edge118of the cup washer111is circular in this example.

The external surface113of the cup washer111is configured with a first recess120and a second recess122. Between the first and second recesses120,122, the external surface113is configured with a contact portion124to contact the wall of the hole into which the cup washer is to be inserted so that the cup washer nests in said hole. With reference toFIG.6, this is wall33of the countersunk hole32.

The contact portion124comprises a plurality of narrow grooves, two of which are shown as126,128inFIG.14. The grooves126,128each provide a pathway between the first and second recesses120,122as shall be described in more detail hereinafter. The contact portion124has four such grooves equally spaced around the contact surface.

The external surface113of the cup washer111may be produced by milling a conventional cup washer of the type shown inFIG.1to provide the external surface with the first minor surface117, the first and second recesses120,122and the grooves126,128. InFIG.15the shape of the external surface of the cup washer prior to milling is shown in phantom (labelled as113′) only in the lower region thereof for clarity.

The first and second recesses120,122extend in a ring around the external surface113of the cup washer111. The first and second recesses120,122provide the external surface with a step-like profile and may include undercut portions.

The cup washer111is essentially symmetrical about the axis r-r′.

FIG.16shows the cup washer111nested with the head portion3of the bolt1taken through the line p-p′ ofFIG.14.FIG.17shows how the cup washer111nests in a counter sunk hole in a sheet of glass (i.e. as shown in the first sheet of glass30ofFIG.6).

As discussed above, the internal surface115of the cup washer111is configured the same as the internal surface15of the cup washer11. Given that the bolt1used in this example is configured as previously described, the internal surface115of the cup washer111forms a cavity123in the same way as the cavity23. However, the external surface113of the cup washer111is configured with additional attachment features.

As illustrated inFIG.17, the cup washer111is shown located in a countersunk hole in a first sheet of glass30. The outer edge118of the cup washer and the minor surface117are spaced apart from the first opening of the countersunk hole in the first major surface34of the first sheet of glass30by a space130. The space130provides a path from the sheet of ionomer40to the first recess120. With the contact surface124in contact with the wall of the hole in the first sheet of glass30, the groove126provides a path between the first recess120and the second recess122so that some ionomer material from the sheet of ionomer material can flow from the first recess120into the second recess122. That is, the first recess120is in fluid communication with the second recess by a path formed between the groove126and part of the wall33of the countersunk hole.

The external surface of the cup washer may have more recesses with associated grooves as desired.

FIG.18is similar toFIG.9and shows the unlaminated stack of components prior to a suitable lamination process. The bolt1is shown clamped to the first sheet of glass30by the inner flange63being screwed onto the threaded portion5of the bolt1(with washer62used to avoid direct contact of the inner flange63with the first sheet of glass30).

As can be seen inFIG.18, with the contact surface portion124of the external surface of the cup washer in contact with the wall of the hole, the groove126in the surface thereof provides a pathway between the first recess120and the second recess122. As in the previous example, the channels9a,9b,9cand9dface the sheet of ionomer polymer40and are empty (other than containing the surrounding atmosphere). The first and second recesses120,122, the cavity123and the grooves (only126is labelled inFIG.18) are also empty other than containing the surrounding atmosphere. The space between the wall of the hole, the washer62, the external surface of the cup washer and the stem portion is also empty, other than containing the surrounding atmosphere.

Following a suitable lamination process as shown inFIG.19, some of the ionomer material from the sheet of ionomer material40has flowed through the space130between the outer edge118and minor surface114of the cup washer111and the wall of the hole in the first sheet of glass30into the first recess120. It is preferred that the entire first recess120be filled with ionomer material from the sheet of ionomer material40. Due to the grooves126,128(plus others as desired, there being four equally spaced grooves in this example) in the contact surface124of the external surface of the cup washer111, some of the ionomer material from the sheet of ionomer material40has also flowed into the second recess region122. Again, it is preferred that the entire second recess122contain some of the ionomer material from the sheet of ionomer material40. It is also preferred that the grooves be completely filled with ionomer polymer from the sheet of ionomer material40.

InFIG.19, ionomer material in the first recess120is labelled as120′. Ionomer material in the groove126(pathway between the first and second recesses120,122) is labelled as126′ Ionomer material in the second recess122is labelled as122′.

As in the previous example, the channels9a,9b,9cprovide a pathway for some of the ionomer material to flow through the head portion into the cavity123between the groove in the second surface of the head portion and the internal wall115of the cup washer111.

Following the lamination process, the cup washer111and the bolt1are attached to the sheet of ionomer material40. The additional attachment features associated with the external surface of the cup washer increase the degree of attachment to the sheet of ionomer material. The head portion of the bolt and the cup washer are encapsulated by some of the ionomer material from the sheet of ionomer material40.

Although not exemplified, it is also within the scope of the present invention to have no washer between the head portion and the wall of the hole in the sheet of glazing material. In such embodiments, the second surface of the head portion may be provided with additional attachment features in a similar way as shown for the external surface113of the cup washer111.

Similarly, although the bolts used in the examples of the present invention utilise one or more channels between the first and second surfaces of the head portion, it is within the scope of the present invention for the head portion of the bolt to have no channels therethrough. In such embodiments, the attachment feature is provided by the second surface of the head portion, and/or when present, the external surface of the washer.

The present invention provides an advantage that in the event of breakage of the sheet of glazing material having the hole therein, the potential for the other sheet of glazing material to fall away from the laminated glazing panel (with the sheet of adhesive interlayer material) may be avoided because the sheet of adhesive interlayer material is attached to the glazing fitting, and the glazing fitting is used to secure the laminated glazing panel to a support structure.