GB2381009A

GB2381009A - A non-slip surface

Info

Publication number: GB2381009A
Application number: GB0124837A
Authority: GB
Inventors: Royston Wayne Burnett-Jones
Original assignee: COOPER CLARKE GROUP PLC
Current assignee: COOPER CLARKE GROUP PLC
Priority date: 2001-10-16
Filing date: 2001-10-16
Publication date: 2003-04-23
Anticipated expiration: 2021-10-16
Also published as: GB2381009B; GB0124837D0; GB2381009B8

Abstract

A surface comprises a first set of protrusions (15a...15e, 16a...16e) defining a fluid flow path (12). The surface further comprises a second set of at least one protrusion (13,14), the or each protrusion of the second set being disposed at least partially within the fluid flow path. The second set of protrusions prevents the heel of a shoe, even a narrow heel, from sliding along the fluid flow path, and so provides the surface with a high skid resistance. The skid resistance may be at least 65 as measured in wet conditions by the standard test defined in TRL Road Note No. 27 "Measure of floor slip resistance", and may possibly be at least 75 or even at least 85.

Description

A non-slip surface The present invention relates to a surface that has a high skid resistance, or slip resistance. Such a surface will be referred to as a"non-slip"surface, for convenience.

The non-slip surface of the invention may be applied to, for example, a walk-way, a tread of a stairway, a man-hole cover, a combined kerb and drainage unit, a kerb gully drainage surface or a paving block or paving slab.

One known non-slip surface comprises a layer of irregularly-shaped particles adhered to a substrate. When a person walks over such a surface the irregularly-shaped particles grip the soles of the person's shoes, so that the person's shoes are unlikely to slip.

These conventional non-slip surfaces are effective in dry conditions. They are not, however, effective in wet conditions since the irregularly-shaped particles can trap water with the result that a film of water accumulates, thereby lowering the skid resistance of the surface. If a film water is formed the, in cold weather, a sheet of ice can form over the irregularly-shaped particles, and this destroys the skid resistance of the surface. Furthermore, if the surface is used where vehicles drive over it then oil or other pollutants may collect on the surface and these also lower the skid resistance of the surface. This problem is particularly severe in locations where oil spills are likely, such as the forecourt of a petrol station.

A further known non-slip surface has a plurality of protrusions to increase the skid resistance of the surface. Figure 1 is a schematic plan view of a conventional non-slip surface 1 of this type. The surface comprises a plurality of protrusions 3. Each

protrusion 1 in this prior art non-slip surface is formed by a pair of tetrahedral protrusions 2, 2', arranged with one edge of the base of one protrusion 2 adjacent to an edge of the base of the other protrusion 2'.

The skid resistance of a non-slip surface is reduced if standing water accumulates on the surface. It is therefore important that the protrusions 3 do not completely block the flow of water over the surface 1. This means that it is necessary to space the protrusions 3

from one another so that the non-slip surface contains drainage paths. In the non-slip surface 1 shown in Figure 1, drainage paths exist in the vertical direction (path 4), the horizontal direction (path 5) and the diagonal directions (paths 6,7).

Prior art non-slip surfaces of the general type shown in Figure 1 have the disadvantage that the need to space the protrusions sufficiently far from one another to provide drainage paths means that the drainage channels also constitute"skid channels", so that it is possible for a person to slip and injure themselves. For example, if a person was walking over the non-slip surface 1 of Figure 1 and one of their shoes slipped and began to move along one of the drainage paths, for example along the drainage path 4, there is nothing to arrest the movement of the person's shoe. As a consequence, the person is likely to fall over, and may well injure themselves. Thus, there is an unacceptable risk of accidents and resultant insurance claims against local authorities and the utility companies.

Moreover, if the area of the surface between the protrusions should become polished over time, as a result of use and wear, this risk of accidents exists even in dry conditions. A typical non-slip surface of the type shown in Figure 1 has a skid resistance value of only around 55 in dry conditions, reducing to around 45 in wet conditions. These skid resistance values were measured using the standard test defined in the TRL (Transport Research Laboratory) Road Note 27"Measurement of floor slip resistance".

It might appear that the skid resistance value of the non-slip surface of Figure 1 could be increased by placing the protrusions 3 closer to one another. While this would have some effect in increasing the skid resistance value in dry conditions it would at the same time narrow the drainage paths defined on the surface and so impede the drainage of water from the surface. Thus, in wet conditions it would be more likely that water would accumulate on the surface, but this is not acceptable since the skid resistance of the surface would become very low. Furthermore, many ladies'shoes have very narrow heels, so that adjacent protrusions would have to be located very close to one another in order to completely eliminate the risk of a person's foot slipping-but, doing this would

make it likely that water (and even ice in cold weather) would accumulate on the surface in wet conditions and this is not acceptable.

The present invention provides a surface comprising: a first set of protrusions defining a fluid flow path; and a second set of at least one protrusion, the or each protrusion of the second set being disposed within the fluid flow path substantially to prevent the heel of a shoe from sliding along the fluid flow path. The second set of protrusions provides the surface with a high skid resistance. The or each protrusion of the second set is located such that it does not have any significant effect on the ability of water to drain from the surface along the fluid flow path. Water will not collect on the surface, so that the skid resistance remains high, even in wet conditions.

The present invention may provide a surface having a skid resistance value of at least 65 as measured in wet conditions by the standard test defined in TRL Road Note 27.

Higher skid resistance values of 75 or 85, again as measured in wet conditions by the standard test defined in TRL Road Note 27, may also be obtained.

A second aspect of the invention provides a surface having a skid resistance value of at least 65 as measured in wet conditions by the test defined in TRL Road Note 27.

Further aspects of the present invention provide a man-hole cover, a tread for a stairway, a paving block or paving slab, and a combined kerb and drainage unit comprising a surface as defined above.

Further features of the invention are set out in the dependent claims.

A preferred embodiment of the present invention will now be described by way of illustrative example with reference to the accompanying figures which: Figure 1 is a schematic plan view of a conventional non-slip surface; and

Figure 2 is a schematic plan view of a surface according to an embodiment of the present invention; Figure 3 (a) illustrates one notional grouping of the protrusions of the embodiment of Figure 2 illustrating the presence of drainage channels and the absence of skid channels; and Figure 3 (b) illustrates an alternative notional grouping of the protrusions of the embodiment of Figure 2.

Figure 2 is a plan-view of a surface according to the present invention. The surface is provided with a plurality of protrusions that provide the surface with a high skid resistance. In contrast to the prior art surface of Figure 1, however, the protrusions are arranged to ensure that the surface does not contain"skid channels"along which the heel of the shoe is able to slide, even though the surface does contain fluid flow paths (i. e. , drainage channels) to ensure adequate drainage of water from the surface. This is achieved by disposing protrusions in the drainage channels, so that the maximum distance that a heel of a shoe can slip is very low. However, the protrusions located within the drainage channels are disposed such that they do not block the drainage channels and so do not significantly impede the flow of water through the drainage channels. Two notional groupings of intrusions may be identified in the surface of Figure 2. The protrusions of the first group define, drainage channels, and the protrusions of the second group are located within the drainage channels defined by the first group of protrusions in order to prevent a shoe slipping or at least restrict the maximum skid length.

One notional grouping of the protrusions is shown in Figure 3 (a). A first group of protrusions that defines a drainage channel has been indicated by shading the protrusions belonging to that group. The edges of the drainage channel 12 are indicated schematically in broken lines. It will be seen that other of the protrusions are disposed such that they are partially within the drainage channel, and so serve to reduce the skid length of the surface. For example, the heel of a shoe were to begin to slide along the

drainage channel 12 in the direction indicated by the arrow A, the heel would be able to slide only for a short distance before it would come into contact with the protrusion indicated at 13, at which point further slippage would be prevented.

It will further be noted that the protrusions of the second group, which are disposed within the drainage channel 12, project into the drainage channel from opposite edges of the drainage channel. The protrusion of the second group indicated at 13 projects into the drainage channel from the lower edge 12a of the drainage channel, whereas the next protrusion of the second group-the protrusion indicated at 14-projects into the drainage channel 12 from the upper edge 12b of the drainage channel. As a consequence, even if a very narrow heel, for example a stiletto heel, should slide past the protrusion indicated by 13, along the path indicated by the arrow B, further slippage would be prevented when the heel came into contact with the protrusion indicated at 14.

The non-slip surface of the invention thus prevents even shoes with very narrow heels from slipping.

The protrusions in the first group that define the drainage channel 12 may be considered as comprising a first array that defines the edge 12b of the drainage channel and a second array that defines the lower edge 12a of the drainage channel. Protrusions forming the first array are indicated by 15a... 15e, and protrusions constituting the second array are indicated at 16a... 16e.

Each of the protrusions in the second group, that project into the drainage channel 12, preferably projects into the drainage channel 12 by at least half the width of the drainage channel. If the protrusion (s) of the second group project into the channel by less than half the width of the channel it is possible that a long skid channel could exist.

If the or each protrusion of the second group projects into the channel by slightly more than half the width of the channel (by, say 55 to 60% of the width of the channel), then the flow of water through the drainage channel 12 is not significantly impeded, yet high skid resistance is obtained.

The drainage channel indicated in Figure 3 (a) runs along one diagonal of the surface (as it is represented in Figures 2 and 3 (a). It should be noted that drainage channel exists along the other diagonal of the surface, as indicated by the drainage channel 12'shown in broken lines in Figure 3 (a).

It should also be noted that a plurality of further drainage channels, that are parallel to either the drainage channel 12 or the drainage channel 12'also exist in the surface according to the embodiment of Figure 2. In particular, it should be noted that the protrusions in the second notional group defined in Figure 3 (a) do themselves also define one edge of a further drainage channel. For example, the edge 14a of the base of the protrusion indicated at 14 (which projects into the drainage channel 12) is substantially parallel to the upper edge 12b of the channel 12, and defines one edge of a further drainage channel 12d that runs parallel to the drainage channel 12. It will be seen that the protrusions indicated at 15a to 15e, which form the first group of channels that define the drainage channel 12, project into the drainage channel 12d that is defined by the protrusions that project into the drainage channel 12. That is, in this embodiment, the protrusions of the first group define a drainage channel and the protrusions of the second group project into the drainage channel defined by the protrusions of the first group. Moreover, the protrusions of the second group themselves define a further drainage channel and the protrusions of the first group project into the drainage channel defined by the protrusions of the second group.

It should be noted that the surface of Figure 2 is also effective at preventing slippage in all directions, not just in a direction along the drainage channel 12 indicated in Figure 3 (a). Thus, if a person should slip while walking over a surface of the present invention, the heel of their shoe will not travel very far before the skid is arrested, no matter what the initial direction of the slip of the heel.

It should also be noted that the surface of Figure 2 is also effective at draining water in all directions. This is illustrated in Figure 3 (b) which shows an alternative notional grouping of the protrusions of the surface of Figure 2. In Figure 3 (b), the first group of protrusions that defines a drainage channel is again indicated by shading the protrusions

of the first group. It will be seen that the first group of protrusions again comprises a first array of protrusions 25 that define a first edge 22a of the drainage channel 22, and a second array of protrusions 26 that defines a second edge 22b of the drainage channel 22. The drainage channel 22 shown in Figure 3 (b) is inclined with respect to the drainage channels 12, 12' shown in Figure 3 (a).

It will be seen from Figure 3 (b) that, in this alternative notional grouping of the protrusions of the surface shown in Figure 2, the surface again comprises a second group of protrusions that are project into the drainage channel 22. For example, the protrusions indicated at 23 and 24 are disposed within the drainage channel 22, and prevent the heel of a shoe sliding more than a very short distance along the drainage channel. If a person should slip and the heel of their shoe should start to slide along the drainage channel 22 shown in Figure 3 (b), it could slide only a short distance before coming into contact with a protrusion 23,24 which would prevent further slippage.

In the notional grouping indicated in Figure 3 (b), the protrusions in the second group again define a further drainage channel 22'. The drainage channel 22'defined by the protrusions 23,24 of the second group of protrusions is substantially perpendicular to the drainage channel 22 defined by the first group of protrusions. It will also be apparent from Figure 3 (b) that the drainage channel 22'defined by the second group of protrusions does not have a long skid path, because further protrusions are located

within the drainage channel to produce a low skid length.

I For the notional grouping defined in Figure 3 (a) or Figure 3 (b), the protrusions in the first notional group are arranged such that the long side of the base of each protrusion in the group is parallel to one another. Furthermore, the protrusions are arranged such that the long side of the bases of each protrusion in the second group area also parallel to one another, and are at approximately 90 to the long sides of the bases of the protrusions in the first group.

In the embodiment shown in Figure 2 the protrusions 11 each have the shape of a tetrahedron. Each protrusion has a triangular base, with the sides of the base forming an

isosceles triangle in which the angle between the two sides of equal length 1 la, 1 Ib is approximately 90 . The third side 1 tic of the base is therefore the longest of the three sides of the base.

Four adjacent rows A, B, C, D of protrusions are shown in Figure 2. In each row A, B, C, D, all the protrusions in a row are arranged such that their long sides are substantially parallel to one another. Furthermore, in each row adjacent protrusions are oriented, as seen in plan view, at approximately 180 to one another. The protrusion Al is oriented, as seen in plan view, at approximately 180 to protrusion A2; protrusion A2 is oriented, as seen in plan view, at approximately 180 to protrusion A3 (so that the orientation of protrusion A3 is substantially the same, in plan view as the orientation of protrusion Al) ; and protrusion A3 is oriented, as seen in plan view, at approximately 180 to protrusion A4 (so that the orientation of protrusion A4 is substantially the same, in plan view as the orientation of protrusion A2). This is also true for protrusions B 1 to B4 in row B, for protrusions Cl to C4 in row C; and for protrusions Dl to D4 in row D.

The orientation of the protrusions in the surface of Figure 2 differs from row to row. In row A the protrusions are arranged, as seen in Figure 2, alternately"up" (protrusions Al, A3) and"down" (protrusions A2, A4). By"up"is meant that the vertex between the two sides of equal length of the base of the protrusion is above, as seen in Figure 2, the long side of the base. By"down"is meant that the vertex between the two sides of equal length of the base of the protrusion is below, as seen in Figure 2, the long side of the base.

Each protrusions in row B is oriented with the long side of its base at approximately 90 to the long side of the base of each protrusion in row A. In row B the protrusions are arranged, as seen in Figure 2, alternately"left" (protrusions B 1, B3) and"right" (protrusions B2, B4). By"left"is meant that the vertex between the two sides of equal length of the base of the protrusion is to the left of, as seen in Figure 2, the long side of the base. By"right"is meant that the vertex between the two sides of equal length of the base of the protrusion is to the right of, as seen in Figure 2, the long side of the base.

Each protrusions in row C is oriented with the long side of its base at approximately 90 to the long side of the base of each protrusion in row B, and with the long side of its base approximately parallel to the long side of the base of each protrusion in row A.

Each protrusion Cil... C4 of row C is aligned vertically, as seen in Figure 2, with a protrusion Al... A4 of row A. The base of a protrusion of row C is oriented at approximately 180 to the base of the corresponding protrusion of row A. Thus, protrusion Al is"up"whereas the corresponding protrusion in row C, protrusion Cl, is "down".

Each protrusions in row D is oriented with the long side of its base at approximately 90 to the long side of the base of each protrusion in row C, and with the long side of its base approximately parallel to the long side of the base of each protrusion in row B.

Each protrusion D 1... D4 of row D is aligned vertically, as seen in Figure 2, with a protrusion B 1... B4 of row B. The base of a protrusion of row D is oriented at approximately 180 to the base of the corresponding protrusion of row B. Thus, protrusion B1 is "1eft" whereas the corresponding protrusion in row D, protrusion D1, is "right".

A non-slip surface according to the present invention may have a skid resistance value of at least 65, as measured in wet conditions by the standard test defined in the TRL Road Note 27"Measure of floor slip resistance". A surface of the invention may have a greater skid resistance than 65, for example a skid resistance of at least 75 or even 85 as measured in wet conditions by the standard test defined in the TRL Road Note 27. The skid resistance in wet conditions of a surface according to the invention is thus significantly greater then the skid resistance in dry conditions of the prior art surface of Figure 1.

In one example of a non-slip surface according to the embodiment of Figure 2 the protrusions have a height of approximately 4mm. The half width d of the long side of the base of the protrusion is 6.5mm. The lateral separation si between the mid-point of the base of adjacent protrusions in row A or row C is 20mm. In row B or D the lateral separation S2 between the long side of the base of a"right"protrusion and the long side

of the base of the"left"located immediately to the right of the"right"protrusion is 27mm. The lateral separation S3 between the mid-point of the base of a protrusion in row A or row C and the nearer apex of the base of a neighbouring protrusion is 13.5mm.

Four samples of a composite moulding having this surface were tested according to standard test defined in TRL Road Note 27. It was found that the four samples had skid resistance values, as measured in wet conditions by the standard test defined in TRL Road Note 27, of 79, 83,83 and 86 respectively.

The surface of the invention is not limited to the specific arrangement of protrusions shown in Figure 2, nor to the precise dimensions given in the above example. It is however preferable that the spacing between protrusions is such that the heel of a shoe of normal size (that is, not a very narrow heel such as a stiletto heel) will make contact with a plurality of protrusions across its width and along its length.

The shape of the protrusions is not limited to the specific shape described above. The shape of the protrusions is however preferably chosen so that if oil, water or other pollutants are split over the surface, the oil or water that lands on a protrusion will drain down the protrusion into one of the drainage channels. This will provide a high skid resistance, since oil or water will not remain on the tips of the protrusions-and the soles of most shoes will make contact primarily with the tips of the protrusions.

The surface shown in Figure 2 may be applied to any surface that is required to have a high skid resistance. Possible applications include a man-hole cover, the treads of a stairway or ladder, a walkway, a combined kerb and drainage unit, a kerb gully drainage surface, or a paving block or paving slab. In the case of a man-hole cover, for example, a surface of the invention would be applied to all or substantially all the area of the surface of the man-hole cover intended to be uppermost in use. Typically a surface of the invention would be applied to all of the upper surface of the man-hole cover, except for areas where holes for fastening bolts were provided and possibly except for an area where the manufacturer's name were displayed.

The surface shown in Figure 2 may conveniently be produced by moulding a composite material. Once a suitable mould has been made, the surface may be manufactured in large quantities. Suitable materials for moulding the surface are a vinyl ester, or a structural moulding composite that comprises polyester resins and glass-fibre reinforcement material. This is particularly suitable for a man-hole cover, since it produces a man-hole cover that is light and can easily be handled during installation.

In principle, the surface of the present invention may be produced from any material that is weather-proof and hard-wearing. For example, a man-hole cover or other article to which the surface has been applied could alternatively be cast in a suitable metal.

Alternatively, the surface could be produced in sheet metal using a suitable stamping or embossing technique. As a further alternative, an article having a surface of the invention could be cast in concrete, and this is particularly suitable for the manufacture of paving blocks or paving slabs.

Claims

CLAIMS:

1. A surface comprising: a first set of protrusions defining a fluid flow path; and a second set of at least one protrusion, the or each protrusion of the second set being disposed at least partially within the fluid flow path thereby substantially to prevent the heel of a shoe from sliding along the fluid flow path.

2. A surface as claimed in claim 1 wherein the first set of protrusions comprises a first array of protrusions defining one edge of the fluid flow path and a second array of protrusions defining another edge of the fluid flow path.

3. A surface as claimed in claim 1 or 2 wherein each of the first and second arrays of protrusions is a linearly-extending array.

4. A surface as claimed in claim 2 or 3 wherein one protrusion of the second array projects into the fluid flow channel from one edge of the fluid flow path and another protrusion of the second array projects into the fluid flow channel from the other edge of the fluid flow path.

5. A surface as claimed in claimed in any preceding claim wherein the first set of protrusions defines a plurality of fluid flow paths, and wherein at least a respective one of the second set of protrusions is disposed at least partially within each fluid flow path thereby substantially to prevent the heel of a shoe from sliding along each fluid flow path.

6. A surface as claimed in claimed in any preceding claim wherein the first set of protrusions defines at least a first fluid flow path and a second fluid flow path crossed with the first fluid flow path.

7. A surface as claimed in any preceding claim wherein the base of each protrusion of the first set has a triangular section.

8. A surface as claimed in claim 7 wherein the base of each protrusions of the first set has a section that is an isosceles triangle having first and second sides of equal length and a third side longer than the first and second sides.

9. A surface as claimed in claim 8 wherein the first edge of the fluid flow path is defined by the third side of the base of each protrusion of the first array and the second edge of the fluid flow path is defined by the third side of the base of each protrusion of the second array.

10. A surface as claimed in claim 8 wherein the first edge of the fluid flow path is defined by the first or second side of the base of each protrusion of the first array and the second edge of the fluid flow path is defined by the first or second side of the base of each protrusion of the second array.

11. A surface as claimed in claim 8,9 or 10 wherein the protrusions of the first array are disposed such that the longest sides of their bases are substantially parallel to one another.

12. A surface as claimed in claim 11 wherein the or each protrusion of the second array is disposed such the longest side of its base is not parallel to the longest sides of the bases of the protrusions of the first array.

13. A surface as claimed in claim 12 where the or each protrusion of the second array is disposed such the longest side of its base is substantially at 90 to the longest sides of the bases of the protrusions of the first array.

14. A surface as claimed in any of claims 8 to 13 wherein at least one protrusion of the second group is disposed such that the longest side of its base is at substantially 90 to the axis of the fluid flow channel defined by the first group of protrusions.

14. A surface as claimed in any of claims 8 to 14 wherein each protrusion is a tetrahedron.

15. A surface as claimed in any preceding claim wherein the second group of protrusions define a further fluid flow path, and at least one protrusion of the first set of protrusions is disposed at least partially within the further fluid flow path thereby substantially to prevent the heel of a shoe from sliding along the further fluid flow path.

16. A surface as claimed in any preceding claim and having a skid resistance value of at least 65 as measured in wet conditions by the test defined in TRL Road Note 27.

17. A surface as claimed in claim 17 and having a skid resistance value of at least 75 as measured in wet conditions by the test defined in TRL Road Note 27.

18. A surface as claimed in claim 17 and having a skid resistance value of at least 85 as measured in wet conditions by the test defined in TRL Road Note 27.

19. A surface substantially as described herein with reference to Figure 2 of the accompanying drawings.

20. A surface having a skid resistance value of at least 65 as measured in wet conditions by the test defined in TRL Road Note 27.

21. A surface as claimed in claim 20 and having a skid resistance value of at least 75 as measured in wet conditions by the test defined in TRL Road Note 27.

22. A surface as claimed in claim 20 and having a skid resistance value of at least 85 as measured in wet conditions by the test defined in TRL Road Note 27.

23. A surface as claimed in any of claims 20,21 or 22 and comprising a plurality of protrusions.

24. A man-hole cover comprising a surface as defined in any of claims 1 to 23.

25. A tread for a stairway comprising a surface as defined in any of claims 1 to 23.

26. A paving block or paving slab comprising a surface as defined in any of claims 1 to 23.

27. A combined kerb and drainage unit comprising a surface as defined in any of claims 1 to 23