US20110129612A1

US20110129612A1 - Moving walkways or escalators having anti-slip coating and method for applying an anti-slip coating

Info

Publication number: US20110129612A1
Application number: US12/674,706
Authority: US
Inventors: Marcus Heuberger; Daniel Bruderer
Original assignee: Inventio AG
Current assignee: Inventio AG
Priority date: 2007-08-24
Filing date: 2008-08-14
Publication date: 2011-06-02
Also published as: CN101784471B; BRPI0815902A2; PL2190773T3; CN101784471A; EP2190773B1; EP2190773A1; BRPI0815902B1; WO2009027241A1; ES2454246T3

Abstract

Escalator with a step band with several steps (4), or moving walk with a pallet band with pallets (4), wherein the steps (4) or pallets (4) are made of metal as brass, copper, NIROSTA, steel, magnesium, aluminum, and provided with an antislip coating. The antislip coating comprises a carbide hard substance that is embedded in a, or the, metallic matrix.

Description

The invention relates to an escalator or a moving walk with a step band with steps, or respectively with a pallet band with pallets, for the transportation of persons and/or objects, and steps or respectively pallets that are provided with an antislip coating.
Transportation devices in the sense of the invention, which may also be referred to as mobility devices, are escalators and moving walks with a plurality of tread units, escalator steps, or moving-walk pallets respectively, that are joined to form an endless transporter. Users of the transportation devices stand on tread surfaces of the tread units or of the steps, or walk on the moving-walk pallets or escalator steps, in the same direction as that in which the transportation devices travel or move.
Usually, on account of their low weight, aluminum steps or metal steps, or aluminum pallets or metal pallets, are used. These steps or pallets are usually provided with ribs in the universally known manner. Despite these ribs, the steps or pallets are slippery. If the transportation device is in the open air, or in an area that is near to an outside door, the steps or pallets can become wet or dusty. In various cases, or in the fall, leaves or mud or airborne sand or soil or rubble or dust can find their way onto the transportation device. Especially in these situations, the steps or pallets prove particularly slippery and dangerous.
Particular problems can arise depending on the footwear of the users. Thus, for example, shoes with leather soles, or rubber boots, are particularly slippery.
For this reason, in some cases antislip coatings are used. From DE 100 85 003 T1 and EP 1 169 256 B1 an antislip strip is known that is used on the steps of an escalator.
Trials were performed with the application of fluoride resin. However, safety could not be lastingly assured with this measure. Furthermore, fluoride resin proved too costly and complicated to handle. Steps or pallets coated with fluoride resin have proved to be too expensive. There are, however, additional problems such as a lack of durability, since fluoride resin has a tendency to abrade rapidly and be easily eroded. The reapplication of eroded fluoride resin necessitates the work of dismantling the entire escalator and removing the steps that must be repaired. Maintenance costs are thereby increased and, above all, during such a maintenance operation the escalator or moving walk is not available for use.
Am important disadvantage of the coatings used hitherto is to be seen in that the effect of the coating decreases relatively quickly. In practice, as said, this makes it necessary for the steps or pallets to be removed and newly coated. The associated outlay or worktime is, however, too high. To increase the durability of the coating, a significantly thicker layer would have to be applied. However, thicker layers bring other problems of their own. So, for example, cleaning of the corresponding steps is made impossible.
It is here that the invention sets out to provide a remedy. The invention as it is characterized in Claim 1 solves the problem in that a special type of coating is selected which, relative to the previous methods, is significantly thinner. That is to say, the invention goes in a direction that should not really promise success, since the expert would be inclined to apply a thicker layer to increase the effectiveness and the ruggedness or durability.
A coating technique is used which ensures a very thin and highly adhesive join between the coating and the aluminum step, or the aluminum pallet or the metal pallet. Furthermore, coating materials were selected that make possible a particularly intimate and reliable coating of the metal parts as aluminum parts or steel parts or NIROSTA parts or copper parts or brass parts or magnesium parts.
The advantages achieved by means of the invention are mainly to be seen in that the surface structure of the steps or pallets is not impaired by the application of the coating. Furthermore, and in addition hereto, an important advantage of the invention is that the function and safe, smooth, correct, jerkfree running of the entire transportation device is not impaired by the coating. It is also important to emphasize that the coating has a very long fatigue strength or abrasion resistance or durability or wear resistance.
Preferred embodiments of the transportation device(s) according to the invention are defined in the dependent claims.

The invention is described in detail below in relation to examples and by reference to the drawings. Shown are in

FIG. 1 a side view of an escalator according to the invention;

FIG. 2 a side view of a moving walk according to the invention;

FIG. 3 a plan view of a pallet, or step, of a transportation device according to the invention;

FIG. 4 an elevation of a pallet with antislip coating of a transportation device according to the invention;

FIG. 5 a plan view of an end-part, or head, of a transportation device according to the invention;

FIG. 6 a side view onto the comb plate, and onto the floor covers, of a transportation device according to the invention.

FIG. 1 shows an escalator 1 that connects a first level E1 with a second level E2. The escalator 1 has a step band that consists of steps 4. In the case of a moving walk 1, as shown in FIG. 2, this has a pallet band that consists of pallets 4. A handrail 3 is arranged on a balustrade 2 which at its lower end is held by a balustrade skirt.
FIG. 3 shows a diagrammatic representation of a pallet or step onto which between two and six strips of antislip coating 4.1 of carbide are applied or sprayed.
FIG. 4 shows a pallet 4 with an antislip coating 4.1 of a hard metal layer wherein carbide hard substances (tungsten carbide, chromium carbide, titanium carbide, nickel carbide, or silicon carbide) are embedded in a metallic matrix. The carbide layer is applied to the step area of the moving walk pallet 4 over the entire length. Preferably, two carbide lengthwise strips are sprayed on.
FIG. 5 shows an end part E1, E2, or a head part, of a moving walk 1 or escalator 1 with antislip coating 4.1 which is applied to the pallets 4 or steps 4. In addition, an antislip coating 4.1 is present on the comb plates 7, 8, and on the floor covers 9. Moreover, and in addition, an antislip coating 4.1 is stripwise present on the combs. This embodiment allows the optimal protection against sliding away or slipping off. The carbide layer is sprayed or squirted in two to six strips per floor cover 9 or comb plate 7, 8.
FIG. 6 shows the diagrammatic illustration of the comb plates 7, 8, and of the floor covers 9 with antislip coating 4.1 of carbide. The hard metal coating 4.1 of carbide hard material surrounds the metal parts or aluminum parts and deposits itself in the metallic matrix that is present. The surface of the components or metal parts is surrounded by the antislip coating 4.1 in fine-grained and weather resistant manner. This is applied stripwise by means of a high-speed flame-spraying process. By this means, an antislip surface forms that excellently prevents sliding or slipping.
In the description that now follows, instead of the terms “escalator” or “moving walk”, the term “transportation device” will be used.
Following below, various methods according to the invention of applying an antislip coating 4.1 to the steps 4 of an escalator 1, or to the pallets 4 of a moving walk 1, are described.
According to the invention, a metallic powder material is accelerated and heated by means of a spraying process. Then, by means of a spray-gun, a jet of the heated and accelerated powder material is aimed at the surface that is to be coated. This takes place in such manner that on impact with the metal surface, or alloy surface, or aluminum surface that is to be coated, a homogeneous and fine-grained layer of a carbide hard material results, which is embedded in the metallic matrix.
The metallic powder material that is used is preferably a material that contains tungsten and/or chromium and/or titanium and/or nickel and/or silicon.
Particularly preferred is a high-speed flame-spraying process in which a mixture of oxygen and a flammable substance, preferably a flammable gas (propane or propylene), is used to heat and accelerate the powder material. Instead of the flammable gas, a liquid flammable substance (e.g. kerosene) can be used as flammable substance. Preferably, using nitrogen as carrier gas, the substance to be sprayed is led in powder form coaxially through a nozzle, surrounded by the flame, and thereby uniformly pre-melted and led out of the spray-gun.
In the case of the high-speed flame-spraying according to the invention, the powder material is sprayed with very high speed onto the metal workpiece or alloy workpiece or aluminum workpiece that is to be sprayed. The heat to completely melt the powder material is generated by the reaction of oxygen and flammable substance (e.g. propane, propylene, natural gas, hydrogen, kerosene) in the combustion chamber. The temperatures that are attained in the flame reach up to approximately 3000-4000° C., so that the powder material can be sprayed. The gas expands and accelerates the powder material up to a speed of 400-900 m/s. The workpiece surface, i.e. the metal surface or the alloy surface or the aluminum steps or aluminum pallets 4 need not be previously sand-blasted or roughened since, on impact of the powder material on the workpiece, a type of welding, or adhesive binding and bonding, takes place between the powder material and the workpiece. In high-speed flame-spraying, through the high speed of the powder, a good adhesion of the metallic powder on the workpiece, and a low porosity, are attained. Furthermore, through the selection of a suitable metallic powder, a better material can be created or established that is perfectly suitable as antislip material. The basic material (brass, copper, NIROSTA, steel, magnesium, aluminum) of the step 4 or pallet 4 is thereby enhanced and faultlessly perfected. When tungsten, chromium, titanium, nickel, or silicon is used as metallic powder, in high-speed flame-spraying, optimal layers of tungsten carbide, chromium carbide, titanium carbide, nickel carbide, or silicon carbide are produced. According to the invention, the layer thickness is preferably between 0.08 mm and 0.2 mm. The porosity of the layers approaches zero.
The layers that occur with the method according to the invention are denser, and adhere more firmly, than with other spraying methods such as commercial flame-spraying, arc spraying, or plasma spraying.
The method according to the invention is particularly suitable for hard metal layers wherein carbide hard substances (tungsten carbide, chromium carbide, titanium carbide, nickel carbide, or silicon carbide) are embedded in a metallic matrix. Layers can be manufactured that are characterized by a high wear resistance and/or permanence and/or durability and/or resilience and/or constancy.
In high-speed flame-spraying, the emerging gas jet is used to pre-melt and melt the individual particles of the metallic powder material and accelerate them to a high speed that is four to five times greater than in conventional flame-spraying.
The high-speed flame-spraying process very effectively uses the high kinetic energy of the powder material and, to a limited extent, also thermal energy, to create dense, compact layers with low porosity and high adhesive strength and/or high adhesive pull strength. Some of the layers that are thus produced have an adhesive pull strength of more than 83 Mpa (corresponding to approximately 83 N/mm2) and an exceptionally fine-grained surface.
The process uses, as said, a mixture of oxygen and a flammable substance, which is fed either as a mixture of oxygen and a flammable substance, or as a liquid flammable substance. There are thus two types of spraying system: The gas-operated systems use propylene, propane, oxygen, or natural gas; in the liquid flammable substance systems, kerosene is used. Inside the spray-gun, the respective flammable substance is carefully mixed with oxygen, and emerges through a nozzle, where it is ignited. Preferably using nitrogen as carrier gas, the powder material is led in powder form coaxially through this nozzle, surrounded by the flame, and thereby uniformly pre-melted. Through the gas mixture that emerges at exceptionally high speed, the powder particles are accelerated and, with very high kinetic energy but moderate temperature, are shot or sprayed or squirted onto the workpiece surface. On impact, the powder particles are greatly flattened and surround the base body. Through the low particle temperature by comparison to the other thermal spraying methods, these layers have a forecastable chemical composition and are virtually homogeneous. Furthermore, the layers have a fine-grained structure.
Coatings of this type survive even harsh operating conditions and all-weather operation. Particularly the abrasion or wear is clearly less than with conventional antislip coatings. The antislip coating according to the invention thus offers not only an outstanding protection of the steps 4 or pallets 4, but also a coating that even after relatively long use hardly diminishes in its antislip effect, or not at all. The thickness of the carbide layer remains constant for at least 5 to 10 years, and there are absolutely no signs of wear or weathering or tendency to corrode.
Furthermore, and in addition, the new coating enables the standards EN 115: Safety Rules for the Construction and Installation of Escalators and Passenger Conveyors, and AN American National Standard ASME A17.1-2004: Safety Code for Elevators and Escalators, to be fulfilled. Further investigations show that DIN 51130 is also fulfilled with the highest coefficient of friction R13.
The antislip coating additionally lengthens in outstanding manner the lifetime of the coated components.
Already after the coating, the antislip coating has a very fine-grained surface, a uniform composition, and a low porosity, and counts as completely processed. That is to say, it requires no further processing steps and no further surface treatment.
It is an advantage of the invention that no pretreatment is required, and that the elaborate sand blasting or glass-bead blasting can be obviated in its entirety. This results in a great cost advantage and a great manufacturing (process/cycle) advantage or worktime advantage.
According to the invention, the carbide layers are characterized by a high hardness of almost 1400 NV (Vickers hardness).
Particularly preferred is an embodiment of the invention that is represented in FIG. 3. According to this embodiment, instead of the complete surface being coated, only a number of strips 4.1 (preferably between two and six strips per pallet or step) are applied with strip widths from 20 mm to 75 mm. Through this measure, the quantity of powder material that is used is reduced. The antislip effect is nonetheless adequate, since the strips 4.1 offer adequate adhesion.
It is a further advantage of the invention that the manufacture of the carbide layer on the pallet 4, or on the step 4, or on the comb plate 7, 8, or on the floor cover 9, or on the machine room cover of a transportation device, in one work operation and fully automatically is possible. Preferably, application of the carbide layer takes place by means of a robot, or by means of an automated plant apparatus, or by means of an automated coating apparatus.
Through use of the antislip coating according to the invention, the theoretical angle of slope on the pallet 4, or on the step 4, or on the floor cover 9, without slipping can be very significantly increased relative to known solutions. Consequently, the theoretical angle of slope on the pallet 4, or on the step 4, can be increased from 11 degrees to well over 40 degrees of slope, since the carbide layer excellently prevents sliding or slipping. Furthermore, in the case of wetness and/or soiling (dust, mud, airborne sand, soil, rubble, leaves), sliding or slipping can be optimally avoided and/or prevented by the carbide layer.
As described, the invention can be equally applied to escalators and moving walks.

Claims

1-10. (canceled)

11. A method for applying an anti-slip coating of the type wherein by means of a spraying process a powder material is accelerated and heated, and by means of a spray-gun a jet of the heated and accelerated powder material is directed at the surface that is to be coated, such that on impact with the surface that is to be coated a homogeneous and fine-grained layer of a carbide hard material results, which is embedded in a metallic matrix, characterized in that:

the process is chosen from the group consisting of high-speed flame-spraying and plasma-spraying processes in which a mixture of oxygen and a flammable substance is used to heat and accelerate the powder material; and

the powder material is applied to steps of an escalator or to pallets of a moving walk.

12. The method according to claim 11, wherein the antislip coating is applied to the steps or pallets stripwise.

13. The method according to claim 11 or 12, wherein the powder material is led out of the spray-gun by means of or through a nozzle.

14. The method according to claim 11 or 12, characterized in that, by means of a carrier gas, the powder material is led coaxially through a nozzle, surrounded by the flame, and thereby uniformly pre-melted.

15. The method according to claim 11 or 12, wherein the powder material comprises a material chosen from the group consisting of tungsten, chromium, titanium, nickel, and silicon.

16. The method according to claim 11 or 12, wherein the flammable substance is chosen from the group consisting of propane, propylene, natural gas, hydrogen, and kerosene.