GB2239888A

GB2239888A - Glazing a lift door assembly

Info

Publication number: GB2239888A
Application number: GB9000780A
Authority: GB
Inventors: Alan James Walker; Cyril Laws
Original assignee: FURSE LIFTS Ltd
Current assignee: FURSE LIFTS Ltd
Priority date: 1990-01-13
Filing date: 1990-01-13
Publication date: 1991-07-17
Anticipated expiration: 2010-01-13
Also published as: GB9000780D0; GB2239888B

Abstract

A lift door assembly comprises a framework (1), a pane of glass (2) and a mounting assembly associated with the framework (1), said mounting assembly securing the pane of glass (2) to the framework (1) and comprising clamping means including spaced clamping members and spacing moans to control the minimum spacing between the clamping members. The clamping means comprises a screw (6) extending through the clamping members and a nut (7). The spacing means may be a spacer around the part of the screw (6) in the space between the clamping members. The clamping members may comprise a metal plate (3) shaped to form a bracket portion (5) which is welded to the framework and a metal plate (4) secured to the first metal plate (3) by the screw and nut. As shown, the edge of the glass may be stepped and alumino-silicate packing 10 (for fire resistance) may be provided. <IMAGE>

Description

LIFT DOOR ASSEMBLY This invention relates to a lift door assembly.

It is vitally important that lift doors are able to withstand fire for as long as possible so they must have a high fire rating. Where lift doors contain panes of glass, it is essential that the method used to clamp the glass in place provides a good seal around the edge of the glass otherwise fire is able to leak through the lift doors via the gaps around the glass. It is also important that the clamping apparatus is not too bulky as lift doors must be slim so that they can easily slide open and shut, within the space restrictions imposed by lift standards.

A known method of clamping glass gives a good fire rating of approximately 2 hours, but this system is far too bulky for use in lift doors. The known methods which would not be too bulky for lift doors are either prohibitively expensive or do not provide a satisfactory fire rating, for example a rating of only 1k hours or less.

A lift door clamping system has now been developed by the applicants which is slim -enough and provides a surprisingly increased fire rating of approximately 2d hours.

The present invention provides a lift door assembly comprising a framework, a pane of glass and a mounting assembly associated with the framework, said mounting assembly securing the pane of glass to the framework and comprising clamping means including spaced clamping members and spacing means to control the minimum spacing between the clamping members.

The clamping means preferably comprises tightening means comprising a screw and nut assembly, said screw extending through the spaced clamping members.

Advantageously, the spacing means comprises a spacing element around the part of the screw which is in the space between the clamping members, such that the minimum spacing between the clamping members is controlled by the height of the spacing element.

Conveniently, the marginal portions of the pane of glass to be secured by the spaced clamping members are stepped such that the marginal portions are thinner than the remainder of the pane of glass. The marginal portions of the pane of glass are held between the spaced clamping members. Resilient fire-resistant padding material, suitably alumino-silicate wool, is preferably disposed between each clamping member and the marginal portions of the glass. The alumino-silicate wool is conveniently in the form of tape which is placed along the opposite faces of the marginal portions of the pane of glass.

The spaced clamping members preferably comprise a first metal plate, the side of which remote from the glass is shaped to form a bracket portion which is welded to the framework, and a second metal plate which is secured to the first metal plate by the tightening means, both metal plates extending substantially parallel to each other for the length of the pane of glass. Preferably, metal plates of approximately 500 mm are used adjacent each other along the length of the glass. A gap of 2 to 3 mm is left between adjacent plates to allow for expansion.

A preferred embodiment of the invention will now be described in detail with reference to the accompanying drawings in which: Figure 1 shows a corner of a lift door assembly cut away; and Figure 2 shows a section through line A-A of Figure 1.

The lift door assembly comprises a pane of glass 2 and a framework 1, a corner of each being shown in Figure 1. Stepped special fire rated laminated glass is preferably used. The mounting assembly is shown in Figure 2.

Spaced clamping members comprising a first rigid metal plate 3 and a second rigid plate 4 extend longitudinally and parallel with their flat faces opposite to each other for the length of the framework 1, along all four sides of the pane of glass 2. The side of the first metal plate 3 remote from the pane of glass 2 is shaped to form a bracket portion 5 which extends substantially perpendicularly to the rest of the metal plate 3. The bracket portion 5 is fixed to the adjacent part of the framework 1 by a suitable means such as welding.The second metal plate 4 is secured to the first metal plate 3 by a tightening means which conveniently comprises a number of countersunk screws 6 (only one shown in Figure 2) which extend through the metal plates 3, 4 adjacent to the bracket portion 5, and a nut 7 which is threaded onto each screw on the side of the second metal plate 4 remote from the first metal plate 3.

The minimum separation between the metal plates 3, 4 is controlled by spacing elements between the two plates. These are most conveniently metal cylinders 8 (only one visible in the drawings) around the portion of each screw 6 which is between the metal plates 3, 4.

The marginal portion 9 of the pane of glass 2 which is to be fixed by the mounting assembly is stepped, the marginal portion 9 thus being thinner than the remainder of the pane 2.

The marginal portion 9 of the glass is inserted between the metal plates 3, 4 substantially all of the length and width of the marginal portion 9 being enclosed by the metal plates 3, 4.

Alumino-silicate wool 10 is disposed between the glass 9 and each metal plate 3, 4. This is most easily achieved by using alumino-silicate wool in the form of Fibrefax tape, a strip of which is stuck along the two opposite faces of the marginal portion 9 before it is inserted between the metal plates 3, 4.

Each screw 6 is then tightened using the nut 7 until the metal plates 3, 4 contact the metal cylinder 8 and no further compression is possible.

The mounting assembly is very slim, the combined thicknesses of the metal plates 3, 4 being approximately equal to the spacing between them when the pane of glass 2 is clamped in position. The assembly thus fits easily into the framework I and the lift doors are slim enough to be able to slide open and shut easily, and are of attractive, neat appearances. The height of the metal cylinder 8 is chosen so that optimum compression on the marginal portion 9 of the pane of glass 2 is achieved. The compression is even along the width and length of the metal plates 3, 4 leaving no gaps through which fire may leak. It has been found that the lift door assembly of the present invention thus gives a high fire rating of about 2 hours which is significantly higher than the ratings previously achieved in lift doors.

Claims

1. A lift door assembly comprising a framework, a pane of glass and a mounting assembly associated with the framework, said mounting assembly securing the pane of glass to the framework and comprising clamping means including spaced clamping members and spacing means to control the minimum spacing between the clamping members.

2. A lift door assembly according to Claim 1 wherein the clamping means comprises tightening means comprising a screw and nut assembly said screw extending through the spaced clamping members.

3. A lift door assembly according to Claim 2 wherein the spacing means comprises a spacing element around the part of the screw which is in the space between the clamping members, such that the minimum spacing between the clamping members is controlled by the height of the spacing element.

4. A lift door assembly according to any one of the preceding claims wherein the marginal portions of the pane of glass to be secured by the spaced clamping members are stepped such that the marginal portions are thinner than the remainder of the pane of glass.

5. A lift door assembly according to Claim 4 wherein the marginal portions of the pane of glass are held between the spaced clamping members and alumino-silicate wool is disposed between the clamping member and the marginal portions of the glass.

6. A lift door assembly according to Claim 5 wherein the alumino-silicate wool is in the form of tape which is placed along the upper and lower faces of the marginal portions of the pane of glass.

7. A lift door assembly according to any one of the preceding claims wherein the spaced clamping members comprise a first metal plate, the side of which remote from the glass is shaped to form a bracket portion which is welded to the framework and a second metal plate which is secured to the first metal plate by the tightening means, both metal plates extending substantially parallel to each other for the length of the pane of glass.

8. A lift door assembly according to Claim 1 and substantially as described hereinbefore with reference to the accompanying drawings.