AU6534199A - Mechanical walkway with elastomeric surface coating - Google Patents

Description

-1-

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT a.

a sat.; an.

6* a a.

ORIGINAL

Name of Applicant: JOSEPH SZABO Joseph SZABO Actual Inventor: Address of Service: e a.

•c o BALDWIN SHELSTON WATERS 60 MARGARET STREET SYDNEY NSW 2000 "MECHANICAL WALKWAY WITH ELASTOMERIC SURFACE

COATING"

Invention Title: Details of Associated Provisional Application No. PP7789 dated 18 December, 1998 The following statement is a full description of this invention, including the best method of performing it known to me:- -2- Field of the Invention The present invention relates generally to a method of applying a non-slip coating to a substrate, and to a composite product manufactured in accordance with this method.

The invention has been developed primarily in relation to moving mechanical walkways and will be described hereinafter with reference to this application. It will be appreciated, however, that the invention is not limited to this particular field of use.

Background of the Invention i Moving walkways typically include escalators which elevate pedestrian passengers 10 from one level to another, and travelators which move pedestrians from one point to :another, normally on the same level or over a slight incline. Moving walkways of this .type are now commonplace in airports, railway stations, shopping centres and the like.

Such walkways typically comprise a series of rigid metal segments which are pivotally interconnected to form an endless loop, which is driven in the same manner as a conveyor belt. In escalators, the linkages connecting adjacent segments are configured such that the operative segments remain in a substantially horizontal orientation to form a moving staircase. In the case of travelators which generally move horizontally or over a slight incline, the operative segments remain substantially in the same plane, but pivot relative to one another around a pulley or drum at each end of the run. Moving walkways of this type have proven to be highly effective in transporting relatively large numbers of pedestrians in comfort over significant distances. They are, however, subject to disadvantages.

-3- A significant problem is that in wet or rainy weather, moisture causes the metal surfaces of the walkway segments to become slippery. Even under cover, water usually migrates onto walkways from pedestrians' shoes, umbrellas, raincoats and the like. In such conditions, the walkway becomes particularly dangerous. For this reason, moving walkways operating from car parks and similar external facilities are often required to be stopped in wet weather, and covered temporarily with elongate strips of carpet to restore a safe level of frictional contact. However, this renders the moving aspect of the walkway inoperative. Furthermore, the carpets themselves typically become crumpled, leading to the formation of protruding humps over which pedestrians are prone to trip, thereby rendering the walkway potentially more unsafe, even when not moving.

In an attempt to minimise this problem, the upper surfaces of the metal segments of moving walkways are typically formed with longitudinally extending parallel ridges which define intermediate channels to facilitate drainage. In practice, however, it has been found that this does little to reduce the slipperiness of these surfaces in wet o:ooo weather. Moreover, these problems are heightened when the walkways are used by children, invalids, and the physically handicapped.

A further problem, which is exacerbated by the ridged surfaces, is that the clearance spaces between adjacent segments are potentially hazardous. These have been known, for example, to jam and crush fingers and toes, particularly of young children, if caught at the end of the run.

Disclosure of the Invention It is an object of the present invention to overcome or substantially ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative.

-4- Accordingly, in a first aspect, the invention provides a method of applying a nonslip surface to a substrate, said method comprising the steps of:applying a first layer of epoxy resinous material to the substrate; applying a second layer of polyurethane material over the first layer; and allowing the first and second layers to cure, thereby to form a non-slip surface bonded to the substrate.

In a second aspect, the invention provides a substrate incorporating a non-slip surface bonded thereto, in accordance with the method as defined.

•oooo •Advantageously, the polyurethane surface formed by the second layer is durable, non-toxic, and non-slip, as well as being resistant to oil, most chemicals, and ozone.

"Preferably, the substrate is metal, and consists of an exposed upper surface of a segment of a moving walkway. Preferably also, the method is applied to upper surface of each segment in the walkway such that, in use, substantially the entire operative surface of the walkway is provided with a non-slip surface.

•oooo Preferably, the upper surface of each segment of the walkway constitutes a series of longitudinally extending, uniformly spaced apart, parallel ridges, defining a corresponding array of intermediate channels. The ridges are preferably around 3 mm in width. In this embodiment, the non-slip surface is preferably applied only to the ridges, without extending into the channels.

The first and second layers are preferably applied in a "tacky" state by means of a roller and the polyurethane rubber is preferably coloured black.

Preferably, the first layer is between 0.1 mm and around 0.5 mm thick, and ideally around 0.2 mm thick. Preferably, the second layer is between 1 mm and around 5 mm thick, and ideally around 2 mm thick. The polyurethane material preferably has a hardness of 50+ 5 (shore hardness).

Preferably, the method includes the preliminary step of roughening the surface of the metal substrate by sanding, grinding, scraping, abrading, chemical etching, or other suitable means to enhance bond strength.

Brief Description of the Drawings A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing which is an enlarged cross- S: !°sectional end elevation showing the upper surface of a walkway segment including a non-slip surface coating applied in accordance with the method of the present invention.

Preferred Embodiment of the Invention Referring to the drawing, the invention has been developed for use with a moving S•walkway 1 comprising a series of interconnected metal segments 2 which are driven as an endless loop between spaced apart pulleys (not shown) in conventional manner. The upper surface of each segment of the walkway is defined by a series of longitudinally S"extending, uniformly spaced apart, parallel ridges 3, each ridge being approximately 3 mm in width. The ridges define a corresponding array of intermediate channels 4. At each end of the walkway, a series of fingers protrude from a cleaning comb (not shown) into the respective channels to prevent debris from passing into the drive mechanism (also not shown). The general nature and structure of such walkways is well known to those skilled in the art.

Turning then to describe the method of the present invention, initially the metal substrate, comprising the upper surfaces of the longitudinal ridges 3, is roughened by -6sanding, grinding, scraping, abrading, chemical etching, or other suitable means. The roughened surface is then cleaned and degreased using acetone or similar volatile solvent.

Thereafter, a first layer 7 of epoxy resinous material is applied in an uncured or partially cured state to the substrate. This first epoxy layer is preferably between 0.1 mm and around 0.5 mm thick, and ideally around 0.2 mm in thickness. The application step is performed by means of a roller. It has been found that this is effective in providing relatively uniform coverage over the top surfaces of the ridges 3, without the epoxy flowing into the intermediate channels 4. This is important because the fingers of the oo 10 cleaning combs at each end of the walkway extend into the channels with a close fit, to remove entrapped debris. Consequently, resinous material migrating into the channels could cause jamming, or at least create undesirable frictional resistance.

Subsequently, a second layer 8 of polyurethane material is applied over the first layer 7. The second layer is preferably between 1 umm and around 5 mm thick, and 15s ideally around 2 mm thick. It is noted that several passes with the roller may be required o o0 in order to build up the second layer to the required depth. Again, the use of a roller in this application step has been found to provide effectively uniform coverage of the ridges, without excessmaterial inadvertently migrating into the intermediate channels.

In this respect, the consistency of both the epoxy resin and the polyurethane is important.

A relatively viscous tacky consistency is ideal, whereas excessive fluidity is undesirable.

At this stage, the first and second layers are left to bind and cure, which typically requires 4 to 5 hours. During this process, by virtue of the synergistic interaction with the epoxy, the polyurethane becomes chemically bonded to the underlying substrate.

-7- The result of this is a rubberised layer effectively bonded to the metal substrate, thereby providing a ridged surface 9 which is non-slip, highly durable and non-toxic, while being resistant to oils, ozone and most chemicals.

When used every day in heavy pedestrian traffic environments, it is envisaged that the thickness of the polyurethane layer will decrease by several millimetres over a period of approximately nine to twelve months. At that stage, the coating may be reconditioned, simply by applying an additional polyurethane layer to the existing surface, after thorough cleaning and degreasing. In this case, because the fresh "polyurethane is being applied to a polyurethane substrate comprising the residual portion o• .o of the original second layer, epoxy resin is not required. After this process of reconditioning, the surface should be reusable for a further period of nine to twelve months.

It will be appreciated that the invention thus provides a relatively inexpensive, efficient and cost effective means of providing a non-slip surface to a new or existing oee•• walkway, with minimal downtime. A secondary advantage is that the increased height of the surface ridges of the walkway effectively reduces the clearance spaces between the ridges of adjacent segments, and between the ridges and the cleaning combs at the ends of the walkway, thereby reducing the risk of fingers, toes and foreign objects becoming inadvertently trapped or jammed. In all these respects, the invention represents a commercially significant improvement over the prior art.

Although the invention has been described with reference to specific examples, it will be appreciated that the invention may be embodied in many other forms. In particular, it should be noted that the substrate need not form part of a moving walkway, -8and that the invention is equally applicable in virtually any situation where a rubberised or non-slip surface is required on a substrate.

e

Claims (16)

1. A method of applying a non-slip surface to a substrate, said method comprising the steps of:- applying a first layer of epoxy resinous material to the substrate; applying a second layer of polyurethane material over the first layer; and allowing the first and second layers to cure, thereby to form a non-slip surface bonded to the substrate. 10 2. A method according to claim 1 wherein the polyurethane material is relatively durable, non-toxic, and resistant to oil and most chemicals. °oo°

3. A method according to claim 1 or claim 2 wherein the substrate is metal and consists of an exposed upper surface of a segment of a moving walkway.

4. A method according to claim 3, applied to the upper surface of each segment in the walkway such that, in use, substantially the entire operative surface of the walkway is o provided with a non-slip surface. A method according to claim 3 or claim 4 wherein the upper surface of each segment of the walkway constitutes a series of longitudinally extending uniformly spaced apart parallel ridges defining a corresponding array of intermediate channels.

6. A method of applying a non-slip surface according to claim 5 wherein the ridges are around 3 mm in width.

7. A method to claim 5 or claim 6 wherein the non-slip surface is applied only to the ridges without extending substantially into the channels.

8. A method according to any one of the preceding claims wherein the first and second layers are applied in a tacky state by means of a roller.

9. A method according to any one of the preceding claims wherein the first layer is between 0.1 mm and about 0.5 mm thick. A method according to Claim 9 wherein the first layer is approximately 0.2 mm thick.

11. A method according to any one of the preceding claims wherein the second layer is between 1 mm and about 5 mm thick.

12. A method according to Claim 11 wherein the second layer is approximately 2 mm thick. .ooo.i o13. A method according to any one of the preceding claims including the step of degreasing the substrate prior to applying the first layer.

14. A method according to Claim 13 whereby the degreasing of the substrate is performed with acetone or similar volatile solvent. A method according to any one of the preceding claims, including the further step .i of roughening the substrate prior to applying the first layer to enhance bond strength. °ooo•

16. A method according to any one of the preceding claims, where the step of roughening is performed by sanding, grinding, scraping, abrading, chemical etching, or other suitable means.

17. A method according to any one of the preceding claims wherein the polyurethane material is coloured black.

18. A method according to any one of the preceding claims wherein the polyurethane material has a shore hardness of 40 to -11-

19. A method according to Claim 16 wherein the polyurethane material has a shore harness of 50±5. A substrate incorporating a non-slip surface bonded thereto, in accordance with the method as defined in any one of the preceding claims.

21. A method of applying a non-slip surface substantially as herein described with reference to any of the embodiments of the invention shown in the accompanying drawings.

22. A substrate incorporating a non-slip surface bonded thereto substantially as herein described with reference to any of the embodiments of the invention shown in the accompanying drawings. DATED this 20th Day of December, 1999 JOSEPH SZABO Attorney: STUART M. SMITH Fellow Institute of Patent Attorneys of Australia of BALDWIN SHELSTON WATERS