GB2385877A - Threshold with water-collecting trough and drainage hole - Google Patents

Abstract

A threshold 10 for a door comprises a trough 30 having at least one drainage hole 70 to allow water to escape from the channel. A one-way valve 80 may be included so that water can not be forced up through the threshold by differences in air pressure caused by wind. The valve may comprise a single flap or a separate flap for each drainage hole, or a floating ball valve (ballcock) may be used. A water pervious cover 100 may be provided within the trough, which may include legs 120 to stand on the base of the trough. The cover may have a concave upper surface, and may be in the form of a mesh, perforated plate or may be of sintered metal, plastic or other material. Also claimed is a threshold including a pervious cover but with no one-way drainage valve.

Description

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THRESHOLD The present invention relates to a threshold for a doorway.

It is desirable to prevent rainwater passing under the bottom of a door in a doorway, between the bottom of the door and the threshold of the doorway, from the outside to the inside of the door.

Known thresholds have a trough to receive rainwater which penetrates below the door and drainage holes to discharge rainwater from the trough to outside of the doorway or into a water disposal system. Often a seal (a"threshold seal") is provided at the threshold, mounted on the door at its bottom or on the threshold, to prevent or at least hinder passage of draughts and rainwater beneath the door when it is closed.

Problems arise in that a leakage path for draughts through the drainage holes is provided and wind may blow water through the drainage holes into the trough.

The trough may then fill with water and will then overflow. Due to wind pressure the overflow is likely to be, past the threshold seal (if present), to the inside of the doorway. Even if the trough is only partially filled with water, air flow through the drain holes may cause bubbles to form in the water and the air flow can then carry water, past the threshold seal (if present), to the inside of the doorway. Also detritus may be blown into the trough or otherwise collect in the trough, blocking the drainage holes and again causing the trough to overflow. Furthermore accidents may occur as a result of shoe heels or walking sticks, walking frames or other mobility aids getting caught in the trough.

The present invention aims to overcome or at least mitigate such problems.

In accordance with the present invention there is provided a threshold for a door, comprising one or more members defining a trough to be disposed beneath the bottom of the door, the trough having at least one drainage hole, a one-way valve

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being provided to allow water to escape from the trough through the drainage hole (s) but to resist entry of air and water into the trough through the drainage hole (s).

The one-way valve serves to close the leakage path for draughts which would otherwise be provided through the drainage holes, thereby improving the performance of the threshold seal (if such is provided) when it is not raining, i. e. generally most of the time.

The, or each valve, may be a flap valve, comprising a flap mounted on the underside of a member forming the base of the trough such that wind pressure on the outside of the flap presses the flap against the member to ensure that the drainage holes are closed while in the absence of such wind pressure the flap is not pressed against the outside of the member sufficiently to prevent water draining from the trough through the drainage hole (s).

If there are a plurality of drainage holes, there may be a separate flap valve, each with a respective flap, for each drainage hole or a single flap valve with a single flap which can close all the drainage holes simultaneously.

The valve or valves may alternatively be provided by floating balls, e. g. snorkels, or ballcocks.

Furthermore to inhibit entry of detritus, which could possibly block the drainage hole (s), and to prevent shoe heels or mobility aids being caught in the trough, there may be provided within the trough above the drainage hole (s), a water pervious cover which allows water to enter the trough but prevents items of detritus of more than a certain size reaching the drainage hole (s).

The previous cover may be a perforate cover or a porous cover.

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The perforate cover may be in a form of a mesh or perforated plate. The cover may have a perforate portion with depending legs such that it can rest in the trough, on the base of the trough, with the perforate region towards the top of the trough.

The porous cover may be of sintered metal, plastic or other material The cover may present a concave upper surface to facilitate drainage of water to the perforations.

It may be possible to have the perforate cover without the one-way valves.

The invention is further described below by way of example with reference to the accompanying drawings, wherein: Figure 1 is a sectional view of a threshold according to the invention.

Figure 2 is a sectional view on a larger scale of a part of the threshold, showing a flap valve; and Figure 3 is an inverted plan view of the part of the threshold shown in Figure 2.

Referring to Figure 1 of the drawings, a threshold 10 for a door (not shown) of a building comprises an elongate extruded metal (e. g. aluminium) member 20 of uniform cross-section.

The member 20 defines a channel 30. The mouth of the channel opens upwardly so that the channel constitutes a trough. From the upper edges of the channel a first ramp 50 slopes relatively steeply downwardly and a second ramp 60 slopes relatively less steeply downwardly. An elongate cavity 65 is defined beneath the ramp 60.

The ends of the cavity are left open.

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A row of drainage holes 70 is formed in the base of the channel 30.

Members 80 of stiff sheet polyethylene each have a portion 82 fastened by adhesive to the lower surface of the base 20'of the channel 30, leaving a flap 84 extending beneath a respective drainage hole 70.

The lower ends of the ramp portions 50,60 and the base 20'of the channel portion are formed with pairs of ribs 90', 90"extending lengthwise thereof. The ribs 90" are relatively long compared with the ribs 90'.

A cover 100 is positioned within the trough. The cover has a central perforated section 110 presenting a shallow concave upper surface. Two legs 120 depend from the sides of the cover 100. Apart from the perforations the cover 10 is of uniform section. The cover is held in position in the trough by virtue of protuberances 130 on

the insides of the trough near its base engaging in complementary shallow grooves ging in comp on the outsides of the legs 120.

In use the threshold is positioned at the lower edge of the door opening between the side uprights (jambs) of the opening to extend between the side uprights. The relatively less steep ramp 60 is disposed on the outside of the door. The ribs 90"rest on the lower edge of the door opening and the ribs 90'terminate slightly above the door opening. The threshold is sealed against the lower edge of the door opening by mastic 100 disposed between each pair of ribs 90'and 90". A conventional threshold seal (not shown) to seal against draughts, may be provided mounted on or adjacent the threshold or on the bottom of the door.

During normal rainy weather conditions rain which runs down the outside face of the door either runs down the ramp 60 or into the channel and through the perforations of the cover 100. The rain which discharges through the drainage holes 70 flows into the cavity 65 and may then run out of the ends of the cavity.

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In calm or light wind conditions the flaps 84 deflect downwardly either under their own weight or under the weight of water in the trough so that the drainage holes 70 are open to allow the water to discharge from the trough.

In windier, rainy conditions or during gusts of wind, additional rain which runs down the outside face of the door may be deflected by the wind into the trough.

More rainwater may be blown by the wind under the door into the cavity 65. In the absence of the flaps 84 rainwater from the cavity 65 could be blown into the trough, causing the trough to fill and overflow down the ramp 50 on the inside of the door.

However, the pressure of the wind which blows the rain into the cavity 65 also causes the flaps 80 to be deflected upwardly to close the drainage holes 70 so that water and cold air cannot enter into the trough from outside of the door other than through the perforations in the cover. Thus the trough is less likely to fill and overflow. During lulls in the wind the flaps 84 deflect downwardly to allow the rainwater in the trough to be discharged.

The flaps 84 and the base of the channel 30 thus constitute one-way drainage valves which track the changing balance of forces between positive air pressure outside the building (attempting to force cold air and water inside) and the weight of water in the trough acting to open the valves. When the internal air pressure and weight of water exert greater forces on the valve flaps 84 than the external air pressure, the valves open to enable water to drain outside. When the external air pressure is greater than the combined effects of internal air pressure and the weight of water collecting to drain away, the valves close to prevent cold air and or water droplets being forced back through the drainage routes into the building. After gusts of wind, falling external air pressures enable the valves to reopen to allow any remaining water to drain back outside.

As the valves respond to changing weather conditions, the mode in which each valve functions switches between one which delivers best performance against air pressure and one which gives best performance to allow discharge of water from the trough whichever presents the higher priority. This obviates the need to fall back on designs

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which perform optimally in only one type of weather condition or another-or perform moderately well across varying weather conditions. With more than one valve fitted in each threshold section, even variations in weather conditions from one side of a doorway to the other can be accommodated.

The invention should accrue significant gains in overall performance across the long term-improving the comfort and energy efficiency of buildings, regardless of the weather-and representing better value to the consumer than conventional arrangements, wherein the drainage holes of the trough are permanently open, in terms of the cost of the products compared with the savings they contribute to the building's energy and running costs.

Claims (13)

1. CLAIMS 1. A threshold for a door, comprising one or more members defining a trough to be disposed beneath the bottom of the door, the trough having at least one drainage hole, a one-way valve being provided to allow water to escape from the trough through the drainage hole (s) but to resist entry of air and water into the trough through the drainage hole (s).
2. 2. A threshold according to claim 1, wherein the, or each valve, is a flap valve, comprising a flap mounted on the underside of a member forming the base of the trough such that wind pressure on the outside of the flap presses the flap against the member to ensure that the drainage holes are closed while in the absence of such wind pressure the flap is not pressed against the outside of the member sufficiently to prevent water draining from the trough through the drainage hole (s).
3. 3. A threshold according to claim 1 or 2, wherein there are a plurality of drainage holes and there is a separate flap valve, each with a respective flap, for each drainage hole.
4. 4. A threshold according to claim I or 2, wherein there are a plurality of drainage holes and there is a single flap valve with a single flap which can close all the drainage holes simultaneously.
5. 5. A threshold according to claim 1 or 2, wherein the valve or valves are provided by floating balls or ballcocks.
6. 6. A threshold according to any preceding claim, wherein there is provided within the trough above the drainage hole (s), a water pervious cover which allows water to enter the trough but prevents items of detritus of more than a certain size reaching the drainage hole (s).

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7. 7. A threshold according to claim 6, wherein the pervious cover is a perforate cover or a porous cover.
8. 8. A threshold according to claim 7, wherein the perforate cover is in a form of a mesh or perforated plate.
9. 9. A threshold according to claim 7 or 8, wherein the cover has a perforate portion with depending legs such that it can rest in the trough, on the base of the trough, with the perforate region towards the top of the trough.
10. 10. A threshold according to claim 7, wherein the porous cover is of sintered metal, plastic or other material.
11. 11. A threshold according to any of claims 6 to 10, wherein the cover presents a concave upper surface to facilitate drainage of water therethrough.
12. 12. A modification of a threshold according to any of claims 6 to 11, wherein the water pervious cover is present but no one-way valves are present.
13. 13. A threshold substantially as described herein with reference to and as illustrated in the accompanying drawings.