GB2259933A - Doorway threshold - Google Patents

Abstract

A door threshold providing access for wheelchairs, comprising an upstand (20, 21) providing one load-bearing surface spaced by a rain gap from a tread-plate (5), which might be inclined at a shallow angle, resting on a door sill (5). The tread-plate (5) is spaced from the sill (6) to form water-flow channels under the tread-plate, the channels leading to a space between the remote edge of the tread-plate (5) and the sill (6), and from there to a drainage channel. The tread-plate may be retro-fitted to an existing doorway, or be purpose-built. It may be detachable from spacers (25) extending between it and the sill (6), or integral therewith. <IMAGE>

Description

DOORWAYS This invention relates to doorways and particularly external doorways providing improved accessibility for the disabled.

In the construction of doorways into dwelling houses and other buildings from the outside, it is customary to provide a threshold with a vertical stepping and/or a water bar. This requires a person entering the doorway to step up and over the threshold and has the major advantage that water outside the building, for example falling as rain, is hindered from entering the building.

The disadvantage of such thresholds is that they are more difficult to negotiate for the disabled, particularly in the case of those in wheelchairs. Although the wheels are capable of accommodating relatively minor changes in the level of the ground or structure on which they rest, even a step only several centimetres high such is as commonly encountered in an external doorway can pose major problems for the wheelchair user.

I have now found that by careful design relatively much flatter entry may be achieved without compromising the weather resistance at the base of the door.

According to a first feature of the present invention there is provided a threshold construction for use between two load bearing platforms set at substantially the same height, the threshold structure including an upstand adapted to abut the base of a door when the door is closed and including, on the side of the upstand remote from the door, a relatively horizontal or lightly inclined tread-plate supported in a fashion enabling water to flow under the tread-plate, the tread-plate being mounted to leave a channel between itself and the upstand communicating with the space below the treadplate and a channel between the opposite edge of the tread-plate and the adjacent platform and connected to a drainage channel for leading water to waste.

The door to be mounted in the doorway preferably has a weather bar attached thereto on the side adjacent the tread-plate, and positioned such that when the door is closed the weather bar lies over the tread-plate and partially over the channel between the upstand and the tread-plate.

Preferably the door or possibly the upstand or both are provided with elongate seal members adapted when the door is closed to provide an air-seal which, under wind conditions, creates a zone of pressure in the restricted gap between the top of the upstand and the underside of the door. I have found that by providing a main drainage channel below the side of the tread-plate remote from the door and a second drainage channel between the treadplate and the upstand, communicating via channels below the tread-plate with the main drainage channel, it is possible to produce weatherproof threshold constructions where sudden changes in level are reduced and in particular wheelchair access facilitated.

The threshold construction of a doorway in accordance with the present invention may be provided in practice by designing and constructing new doorways in accordance with the teachings of this invention. However it may also be retrofitted into existing doorways, usually accompanied by raising the outer platform i.e. the ground level just outside the house or other building to which the doorway gives access. In the case of subsequent fitting, it is often the case that an existing water bar is provided of relatively narrow width. In such cases it is necessary to build-up the effective width of the water bar by infilling with a suitable additional bar member, the upper surface of which is horizontal in order to provide a zone of air pressure forward of the seal.

The invention is illustrated by way of example only with reference to the accompanying drawings. In these drawings: Figure 1 shows diagrammatically in section the construction of a doorway in accordance with the present invention Figure 2 shows one way of adapting existing designs of thresholds in accordance with the teachings of the present invention and Figure 3 shows an alternative way of adapting an existing threshold design.

Throughout the drawings, like reference numbers are used for like members. Each shows a door 1 communicating between the inside of a building 2 and the outside 3. A weather bar 4 is mounted on the exterior of the door and overlies, when the door is closed, a tread-plate 5. The tread-plate 5 is set on a sill 6 which is supported in turn on the structure of the building e.g. brickwork 7.

To the side of the tread-plate 5 remote from door 1 the "ground level" is defined by a paving slab 8. The bottom of the door is rebated to form a downwardly depending bar 9 integral with the structure of the door and carrying on its external face a resilient seal 10 adapted sealingly to abut an upstand to sill 6 when the door is closed.

Referring now specifically to Figure 1, the side of the tread-plate 5 remote from door 1 has a downwardly depending extension 12 overlying a drainage channel 13.

Between sill 6 and tread-plate 5 are a number of spacers 14 each of which runs transversely to the length of the tread-plate 5. Tread-plate 5 is held on to sill 6, though spaced away from it by members 14, by a plurality of woodscrews 16.

Sill 6 has an integral upstand 17 spaced from the edge of tread-plate 5 to leave a gap down which water entering the space between tread-plate 5 and weather bar 4 can pass, subsequently flowing away between members 14 over the surface of sill 6 to flow-over the edge of sill 6 down into channel 13.

The tread-plate 5 may be made of any suitable material such as brass, steel or an engineering plastics. The preferred material is extruded aluminium alloy. Spacers may be made of wood, plastics or metal.

The structure of Figure 1 is simple and suitable for original installation. However, in many cases it is desired to modify an existing doorway of standard threshold construction in order to facilitate access for the disabled. Figures 2 and 3 show two ways of providing such modification.

Referring to Figure 2, a doorway in which the existing sill 6 has an upstanding metal water bar 20 has attached thereto a wooden fillet 21 by screws 22. Fixed to the upper surface of sill 6 are a number of moulded spacer members 25, for example three to five such members, each held on to sill 6 by a screw 26. The upper surface of each member 25 is interrupted by two slots 28. An extruded aluminium tread-plate 5 has on its under-surface two ribs 29 dimensioned to be a press fit into slots 28 and the edge of tread-plate 5 adjacent door 1 is turned down at 30 enabling tread-plate 5 to be clipped into position over members 25 as shown in Figure 2. This construction is particularly preferred since the upper surface of tread-plate 5 is not interrupted or pierced by apertures, and the entire tread-plate can be simply unclipped (by pulling up on extension 12) to expose the individual members 25 and enable any detritus which has accumulated between members 25 to be swept out.

Figure 3 shows an alternative construction in which the tread-plate 5, which again may be made of extruded aluminium alloy, has a plurality of countersunk holes in it each of which received the head of a screw 32 holding tread-plate 5 on to sill 6 with a number of spacer members 34 located between tread-plate 5 and sill 6, running transversely to the length of tread-plate 5 and defining the channels for water flow downwardly over the top surface of sill 6.

In the case of Figures 2 and 3 the original ground level externally was defined by built-up masonry 40 on to which slab 8 has been placed.

Claims (10)

1. A threshold construction for use between two loadbearing platforms set at substantially the same height, including an upstand adapted to abut the base of a door when the door is closed and, on the side of the upstand remote from the door, a relatively-horizontal or shallowly-inclined tread-plate supported in a fashion enabling water to flow from between the tread-plate and the upstand, under the tread-plate, to a space between the opposite edge of the tread-plate and the adjacent platform, the space being intended to lead to a drainage channel.

2. A threshold construction as claimed in Claim 1, for a door fitted at its base with a weather bar on the side adjacent the tread-plate, the bar being positioned such that, when the door is closed, the bar extends over the gap between the upstand and the tread-plate, and partially over the tread-plate.

3. A threshold construction as claimed in Claim 1 or 2, in which the door and/or the upstand is or are provided with an elongate seal member adapted, when the door is closed, to provide an air seal between the door and the upstand.

4. A threshold construction as claimed in any preceding Claim, in which the tread-plate is supported by spacers extending between it and a door sill, the spacers extending transversely to the axis of the tread-plate.

5. A threshold construction as claimed in Claim 4, in which the spacers are integral with the tread-plate.

6. A threshold construction as claimed in Claim 4, in which the spacers are attached independently to the door sill, and in which the tread-plate is demountably secured to the spacers.

7. A threshold construction as claimed in Claim 4 or 6, in which the upper surfaces of the spacers have aligned recesses in them adapted to receive ribs projecting from the undersurface of the tread-plate.

8. A threshold construction as claimed in Claim 7, in which the tread-plate is a product of an extrusion process.

9. A threshold construction as claimed in any preceding Claim, in which the upstand takes the form of an upright metal water bar having a fillet adjacent thereto and forming a load-bearing surface substantially flush with the adjacent edge of the tread-plate.

10. A threshold construction substantially as described herein and as shown in Figure 1, Figure 2 or Figure 3 of the accompanying drawings.