GB2267307A

GB2267307A - Double glazed units

Info

Publication number: GB2267307A
Application number: GB9210236A
Authority: GB
Inventors: Gordon Arthur Bolton; Anthony Richards
Original assignee: PROMTEL Ltd
Current assignee: PROMTEL Ltd
Priority date: 1992-05-13
Filing date: 1992-05-13
Publication date: 1993-12-01
Anticipated expiration: 2012-05-13
Also published as: GB2267307B; GB9210236D0

Abstract

The invention concerns double glazed units which, ordinarily, may be hazardous in a crisis in view of their resistance to fracture. The invention provides a double glazed unit which has between the two sheets of glass (1, 2) a glass- fracturing member (5) so constructed and located that, on the outer face of either of the sheets of glass (1, 2) being struck adjacent the members (5), the member (5) promotes fracture of at least one of the sheets of glass (1, 2). <IMAGE>

Description

DOUBLE GLAZED UNITS The invention concerns double glazed units and their production.

Double glazed units are widely used, in particular because of their heat and sound insulating properties. However, double glazed units can be a hazard in the event qf a crisis such as a fire when it is desired e.g. for a person or animal to pass through a double glazed area such as a door or window. Double glazed units are typically far more resistant to fracture of the glass than a single sheet of glass and can be very difficult to fracture, especially in emergency conditions. Even quite hard objects such as the heel of a shoe may be insufficient to fracture the glass of a double glazed unit. The problem can be particularly serious because, although one or more of a number of double glazed units available in the event, for example, of a person needing to escape may be designed to be openable, its size and/or location may make it ill-suited for escape or similar purposes and in any event it may be difficult to open or may require the use of a key which may not be readily available in a crisis.

According to the invention a double glazed unit is characterised in that between the opposed faces of the two sheets of glass there is a glass-fracturing member so constructed and located that, on the outer face of either of the sheets of glass being struck adjacent the member, the member promotes fracture of at least one of the sheets of glass.

The glass fracturing member preferably comprises at least a part of relatively hard material so that when desired it promotes fracture of at least one of the sheets of glass. The hard material may be, for example, ,a plastics material, a metal or metal-based material or a carbon-based material e.g. a metal carbide.

The glass-fracturing member is preferably positioned substantially normal to the plane of the double glazed unit. The glass-fracturing member may extend the full width of the gap between the opposed faces of the two sheets of glass, or only a part of that width. The hard material of the member preferably has, at or adjacent at least one of the sheets of glass, a point or points, which may be slightly blunted, to promote fracture of the glass when desired. Preferably the hard material of the member has a point at each end, thereby promoting fracture of both the sheets of glass. Alternatively, the hard material of the member may be, for example, in the form of a spheroid.

Whilst the glass-fracturing member comprises at least a part of hard material, it is preferred that at at least one end it should have a further part, in particular to facilitate holding the member in a desired position, and this further part or parts need not be of hard material. It is in fact preferred that the further, end part or parts should be of a relatively soft material e.g. a soft plastics material or an elastomer as this reduces the risk of accidental fracture of the glass e.g. in the event of a high wind or if the double-glazed unit is unintentionally struck.

Moreover, suitable hard materials are commonly of relatively high thermal conductivity and to limit thermal conduction through the double glazed unit it is therefore desirable to avoid a continuous bridge of relatively high conductivity matter across the space between the two sheets of glass. Such materials as relatively soft plastics material and elastomers are advantageous for the end parts of the member as they are generally of relatively low thermal conductivity.

The end parts of the glass-fracturing member as described in the foregoing also have the advantage of generally being easier to secure to the glass than the relatively hard materials most suitable for achieving fracture of the glass.

Whilst the end parts of the glass-fracturing member have the advantages indicated in the foregoing they are of sufficient softness and/or limited extent that they do not prevent the hard, glass-fracturing part serving its purpose as, when the outer face of the glass is firmly struck, either or both ends of the hard part can be brought into contact with the respective glass surface or surfaces.

For each double glazed unit in accordance with the invention there is at least one of the glass-fracturing members and, in the case of a unit of large area, a number of the members may be present so that there is no need to strike the unit in just one particular area is order to effect the desired fracture. Irrespective of the number of the members, it is preferred that the member or each of the member should be located at some distance from the nearest edge or edges of the unit as this facilitates achieving the fracture when required. Preferably the member or members is or are located in a laterally generally central position or positions.

The glass-fracturing members may be of small width e.g. a few millimetres and thus may be visually unobtrusive. Moreover, the members may be made wholly or partly of translucent or transparent materials.

The double glazed units may be made in accordance with the invention by locating one or more of the glass-fracturing members in a suitable position or positions on one of the two component sheets of glass and causing it or them to adhere there and then either locating the second sheet of glass in position to bear against the free end of the member or of each of the members and causing that sheet to adhere to the free end of the or each of the members or locating the second sheet in position spaced from the free end of the member or of each of the members, if that is the desired structure. The adherence of the member may be achieved entirely by contact and compression but it is preferred to use an adhesive and/or suction cups.

The invention is further described with reference to the accompanying drawings in which: Figure 1 is a transverse vertical section through the lower part of a double glazed unit according to the invention having one form of glass-fracturing member; Figure 2 is a section similar to Figure 1 except that in this case the glass-fracturing member is of a different form; and Figure 3 is a section similar to Figure 2 except that in this case the glass-fracturing member is of another different form.

Referring to Figure 1, the unit has sheets 1 and 2 of glass held in a seating or frame member 3 and spaced apart by a spacer 4.

Between the sheets is located a glass-fracturing member 5 comprising a housing 6, which may be of generally cylindrical form and has dished ends 7 and a cavity 8 and, within the cavity 8, a part 9 of hard material e.g. steel which may be of generally cylindrical form and has pointed ends 10. The housing 6 may be of a plastics or elastomeric material.

Referring to Figure 2, the unit is the same as that of Figure 1 except that the glass-fracturing member, 15, is of a different form. The member 15 comprises a housing 16, which may be of generally cylindrical form and has a part-spherical cavity 18.

Partly located within the cavity 18 but having a projecting portion is a sphere 19 of hard material e.g. steel. It may be noted that the member 15 does not extend across the full width of the cavity between the sheets 1 and 2 of glass and it is secured to the sheet 2 by, for example, an adhesive. The housing 16 may be of a plastics or elastomeric material.

Referring to Figure 3, the unit is the same as that of Figure 2 except that the glass-fracturing member, 115, is of a different form. The member 115 comprises a housing 116, which may be of generally cylindrical form, and has partly embedded within it a multiply-spiked component 119 of hard material e.g. steel. As in the unit of Figure 2 the glass-fracturing member does not extend across the full width of the cavity between the sheets 1 and 2 of glass and it is secured to the sheet 2 by, for example, an adhesive. The housing 116 may be of a plastics or elastomeric material. In a variant of the unit of Figure 3 the component 119 may be entirely embedded in the housing 116 and the housing may extend across the full width of the cavity between the sheets 1 and 2 of glass.

Claims

1. A double glazed unit in which between the opposed faces of the two sheets of glass there is a glass-fracturing member so constructed and located that, on the outer face of either of the sheets of glass being struck adjacent the member, the member promotes fracture of at least one of the sheets of glass.

2. A unit according to claim 1 in which the glass-fracturing member comprises at least a part of relatively hard material able to promote fracture of the glass.

3. A unit according to claim 2 in which the hard material of the glass-fracturing member has, at or adjacent at least one of the sheets of glass, a point or points to promote fracture of the glass.

4. A unit according to claim 2 or claim 3 in which the glass-fracturing member has at at least one end a part of relatively soft material.

5. A unit according to any proceedings claim 4 in which the glass-fracturing member is positioned substantially normal to the plane of the unit.

6. A method of making a double glazed unit according to claim 1 comprising locating one or more of the glass fracturing members in a suitable position or positions on one of the two component sheets of glass and causing it or them to adhere there and then either locating the second sheet of glass in position to bear against the free end of the member or of each of the members and causing that sheet to adhere to the free end of the or each of the members or locating the second sheet in position spaced from the free end of the member or of each of the members, if that is the desired structure.

7. A double glazed unit substantially as hereinafter described with reference to and an illustrated in the drawings.