NL2021944B1

NL2021944B1 - A cleaning pad for an escalator or moving walkway

Info

Publication number: NL2021944B1
Application number: NL2021944A
Authority: NL
Inventors: Rosenbaum Ori; Tao Liu
Original assignee: Escateq B V
Priority date: 2018-11-06
Filing date: 2018-11-06
Publication date: 2020-05-15
Also published as: CN111137776A; CN210825059U

Abstract

The present invention relates to a cleaning pad for an escalator or moving walkway, the cleaning pad comprising: a contact surface comprising ridges and/or grooves, for contacting ridges and/or grooves of the escalator or moving walkway, wherein at least the contact surface of the cleaning pad is made of a single absorbent material, which material is an open cell flexible foamed material, in particular a foamed polyurethane.

Description

Dit octrooi is verleend ongeacht het bijgevoegde resultaat van het onderzoek naar de stand van de techniek en schriftelijke opinie. Het octrooischrift komt overeen met de oorspronkelijk ingediende stukken.

A cleaning pad for an escalator or moving walkway

The present invention relates to a cleaning pad for an escalator or moving walkway, an escalator cleaning head provided with at least one such cleaning pad and an escalator cleaning system, provided with at least one cleaning pad or escalator cleaning head.

Public moving walkways or escalators are among the most expensive, most trafficked, most visible and most dangerous of all flooring areas on earth.

While most flooring, including those that lead up to and away from escalators, are typically cleaned daily, the far more expensive, more visible, more trafficked and more dangerous escalators are relegated to infrequent cleaning. This is primarily due to the expense and complexities associated with escalator cleaning machines and services available and most commonly used today. Escalators are typically provided with multiple interconnected escalator steps, each having a number of parallel ridges and grooves. These ridges and grooves provide for a rather rough surface, preventing people from slipping on the step surfaces. On the other hand dirt, mud, soil and debris also tend to collect in these grooves, while these grooves are difficult to access.

It is therefore an object of the present invention to provide an improved escalator cleaning system.

The present invention thereto provides a cleaning pad for an escalator or moving walkway, the cleaning pad comprising: a contact surface comprising ridges and/or grooves, for contacting ridges and/or grooves of the escalator or moving walkway, wherein at least the contact surface of the cleaning pad is made of a single absorbent material, which material is an open cell flexible foamed material, in particular a foamed polyurethane.

The contact surface of the cleaning pad is provided with ridges itself, such that the ridges may interlock with the grooves of the escalator to be cleaned, wherein these ridges of the pad may thus extend into the grooves of the escalator steps.

The cleaning pad may for instance be used in conjunction with a liquid cleaning solution. The pad with the ridges may then be used to dispense the liquid cleaning solution onto the escalator threads (or ridges and grooves), and once the dirt begins to moisten, emulsify and loosen, the cleaning pad contact surface material is what accomplishes the actual cleaning. In order to take up either fluid cleaning solution, moisture, or liquid mud, dirt or debris, the cleaning pad is made of absorbent material, such that the liquid cleaning solution may be held by the cleaning pad. The cleaning pad thus acts as a sort of sponge.

By single absorbent material is meant that the complete contact surface of the cleaning pad is made of the same material. This eliminates the need of using multiple materials, for instance one material for absorbing a cleaning liquid and one material for rubbing or abrading the escalator step surface. Although using multiple materials may allow to select the material based on their specific purpose, bonding different materials together is costly and cumbersome, results in a slower production process and a more expensive cleaning pad in the end. Single absorbent material may also mean that the contact surface is made of one single pad, of a single material. There is then no separate material or additional pad on one of the sides of the cleaning pad, for instance on the side of the pad that rubs against the combs of an escalator during cleaning thereof.

In a preferred embodiment, the pad is both absorbent and rigid, wherein the pad has a rigidity over 70-ILD, more in particular over 80-ILD and preferably over 90ILD, as measured according to ASTM-D3574, in particular the B1 method thereof with a 4 inch thick sample. The rigidity of the pad is needed in order provide the pad with sufficient strength to be able to abut against the combs of the escalator, the location where the pad generally has to withstand the most pressure. The rigidity of the pad also aids in the scrubbing action the ridges of the pad make in the grooves of the escalator. Since the complete cleaning pad according to the invention is both absorbent and rigid, the complete cleaning pad contributes to their absorbing and rigid functionality, which increases the cleaning action of the pad per surface area.

ASTM D3574 is a widely accepted test standard for testing soft polyurethane foam. There are several test procedures in this standard to help determine the compression, deflection, tear and tensile characteristics of flexible cellular materials (urethane foams and polyurethane foams). IFD (Indentation force deflection) and ILD (indentation load deflection) are two of the more common compression tests in this standard, and are interchangeable. The test consist of measuring the force necessary to produce a designated indentation in the foam product. Within ASTM D3574, the indentation force deflection procedure is Method B1 which measures the force (in pounds) required to indent an eight inch diameter steel plate (called an indentor foot) into a foam sample to a stated percentage of the test sample's initial height which is commonly four inches. The test procedure, for example, compresses a four inch thick sample of foam until it reaches three inches thick, and the compressive load needed to displace it is measured. Common IFD values are generated at 25 and 65 percent of initial height. As an example, 35 lb IFD foams are associated with medium firm foam mattresses, and 45 lb IFD foams are associated with very firm mattresses.

In an embodiment, the cleaning pad is not provided with a backing layer, in particular not provided with a backing layer made of polyethylene. As indicated above, the cleaning contact surface is made of a single foam material. Such backing or backer materials may be used in cleaning pads to impart the required rigidity to the cleaning pad. The cleaning pad of the invention however may have sufficient rigidity on its own, and the need for a backing layer of backer is eliminated. The backing layer, or the backing layer, typically is a separate layer of relative rigid material arranged on one side of a cleaning pad, with the sole purpose of protecting the cleaning pad.

The cleaning pad may for instance be used to clean an escalator while the escalator is moving or turning. The steps rise towards the top of the escalator, turn inwards and move down again on the inside of the escalator, not visible for people using the escalator. At the top of the escalator, steps are thus coming one after the other. The cleaning pad may be arranged at the top. The part of the escalator which forms the transition between the escalator steps and the top deck is called the comb. The required rigidity of the cleaning pad is such that the pad can be placed on top of the escalator, against the comb of the escalator, whereas the cleaning pad is not damaged on the comb upon the force of the moving escalator steps. The steps move sequentially underneath the cleaning pad, and the interlocking ridges and grooves clean each subsequent step.

The density of the contact surface may for instance be over 20 kilogram per cubic meter, in particular over 30 kilogram per cubic meter, more in particular over 40 kilogram per cubic meter, for instance measured according to IS0845:2006. A relative high density of the contact surface results in a tighter packed contact surface, able to withstand more forces which increases the cleaning and rubbing capacity of the contact surface of the pad, and the ridges thereof in particular. The density of the contact surface should, on the other hand, preferably be not so high that the ridges cannot deform slightly anymore, to accommodate possible variations in geometry between different escalator steps, and the threads thereof in particular.

In a preferred embodiment, the indentation hardness of the contact surface is at least 250N at 25%, at least 350N at 40% and/or at least 800N at 65%, more in particular at least 300N at 25%, at least 400N at 40% and/or at least 900N at 65%, as measured according to ISO 2439:2008. Indentation hardness tests are used in mechanical engineering to determine the hardness of a material to deformation. Hardness measurements quantify the resistance of a material to plastic deformation. A relative hard quality of the contact surface results in a pad able to withstand more forces which increases the cleaning and rubbing capacity of the contact surface of the pad, and the ridges thereof in particular. The hardness of the contact surface should, on the other hand, preferably be not so high that the ridges cannot deform anymore, to accommodate possible variations in geometry between different escalator steps, and the threads thereof in particular.

The indentation hardness of flexible cellular materials is a measure of their loadbearing properties. This International Standard specifies four methods (A to D) for the determination of indentation hardness and one method (E) for determination of compressive deflection coefficient and hysteresis loss rate of flexible cellular materials. The 25-40-65% is method B of the standard.

The open cell flexible foam preferably has a pore distribution of between 40 and 90 pores per inch, in particular between 50 and 80 pores per inch. The pore distribution may be a measure for the porosity or absorbency of the pad. The open cell flexible foam preferably has a cell diameter between 25 and 75 microns or micrometre. The number of pores per inch and the size of the pores determine permeability. The provided range for the pore distribution is found to be particularly suited for cleaning escalator steps.

The cleaning pad may comprising a connecting surface, arranged on an opposite side of the pad compared to the contact surface, for connecting the cleaning pad to an escalator cleaning head, wherein the connecting surface may be provided with coupling elements, preferably cooperating with complementary coupling elements on the escalator cleaning head. Typically, the contact surface of the cleaning pad is arranged towards the ground, or bottom, or towards the surface of the escalator steps to be cleaned, whereas the connecting surface is arranged towards the sky, or on top, towards the cleaning head. The coupling elements are preferably made in one piece with the cleaning pad, and are made of the same material. The connecting surface and the coupling elements allow the pad to be coupled or connected to another structure. This structure may thus be an escalator cleaning head, or be part of a cleaning system. In particular, the structure may be provided with a handle, to allow cleaning motions to be performed from a distance from the pad.

The cleaning pad may further be arranged for cleaning risers of an escalator and/or arranged for cleaning ridges and/or grooves of a walking surface of an escalator. The walking surface of the escalator is typically a horizontal surface, whereas the risers for a mainly vertical surface. It may for instance be envisioned that the pad may be turned 90 degrees, or that the ends of the pads, perpendicular to the contact surface of the pad, is also provided with ridges as well.

The cleaning pad may be formed by mixing a poly-isocyanate compound and a polyol and/or a polyamine compound and allowing the compounds to react, wherein the poly-isocyanate compound preferably is a diisocyanate, preferably difenylmethane-4,4’-diisocyanate (MDI), possibly also including additives like castor oil. The reaction is typically a polymerization reaction. Polyurethane foams may be formed by a reaction of these components. Isocyanates are generally very reactive materials. Polyols are polymers in their own right and have on average two or more hydroxyl groups per molecule. Polyether polyols are mostly made by co polymerizing ethylene oxide and propylene oxide with a suitable polyol precursor. If water is present in the reaction mixture (it is often added intentionally to make foams), the isocyanate reacts with water to form a urea linkage and carbon dioxide gas and the resulting polymer contains both urethane and urea linkages. This reaction is referred to as the blowing reaction

The rigidity of the pad may be changed by the changing ratio of isocyanate to polyol. The required rigidity may for instance be achieved by increasing this ratio to over 0.25:1, in particular over 0.33:1. By increasing the amount of isocyanate, the amount of hard segments in polyurethane is increased. Alternatively, the amount of alcohol groups, or-OH groups, in the polyol may be changed. Polyols with high functionality result in rigid, more cross-linked polyurethane foams. For instance, the polyol may thus be a high functionality polyol, or a polyol with 3-8 hydroxyl groups per mol.

In an embodiment, the functionality of the polyol, or the amount of alcohol, or -OH, groups of the polyol, is expressed as N. For instance, the polyol may be a trihydroxy polyether, and N would be three. The amount of polyol times N may be expressed as the functional amount polyol. The ratio of functional amount polyol to the amount of isocyanate may be between 1:1,33 and 1,33:1, preferably between 1:1,25 and 1,25:1. De amount of polyol may be tot total weight of polyol compounds. The amount of isocyanate may be the total weight of isocyanate compounds.

Rigid polyurethane foam recipes may comprise a number of ingredients. Polyols for instance are a source of hydroxyl (OH) or other isocyanate reactive groups. Processing and properties of the resultant foam can be markedly influenced by the choice of starting polyol structure. Polyols mainly used for PURs are low molecular weight hydroxyl terminated polyethers, polyesters and natural products (e.g. castor oil). Polyether polyols are produced by addition of 1,2-propylene oxide (PO) and ethylene oxide (EO) to the hydroxyl group (or amino groups) of low molecular weight molecules, usually by anionic chain mechanism. Polyester polyols are prepared by the polycondensation reaction of di-, or polycarbonic acid or their anhydrides (e.g. phthalic acid, phthalic anhydride) with di- and polyalcohols (e.g. ethylene glycol). Isocyanate may provide a source of NCO groups to react with functional groups from the polyol, water and other ingredients in the formulation. Typically for PURs the recipes provides an excess of isocyanate in order to obtain the desired final properties.

Also catalysts may be used. Of the many classes of compounds investigated, the amines and the organometallics have been found most useful. Various combinations of catalysts are used in order to establish an optimum balance between the polymerization and the blowing reaction. The polymer and gas formation rates must be balanced so that the gas is entrapped efficiently in the gelling polymer and the cell-walls develop sufficient strength to maintain their structure without collapse or shrinkage. Catalysts are also important for assuring completeness of reaction or “cure” in the finished foam. The catalysts most commonly used are tertiary amines such as triethylamine, and alkali metal salts, e.g. potassium acetate. Some catalysts such as tertiary amines affect both the polymerization and the blowing reaction, while others like dibutyltin dilaurate promote primarily the polymerization reaction and chain propagation.

Additionally, blowing agents may be used producing a cellular structure in polymeric matrix via a foaming process. During the polymerization reaction they give rise to gas bubbles which inflate the polymer. Also surfactants may be used in producing rigid polyurethane foams, for instance nonionic, silicone-based surfactants which may stabilize cell walls.

In an embodiment, the foam ingredient comprises:

Ingredient	content
Polyether polyol, such as PPG 5602	2-4%, such as 3%
Polymeric polyol, such as POP 2045	50-65%, such as 60%
Toluene diisocyanate	20-30%, such as 25%
Water	0-2%, such as 1%
Silicone oil	0-1%, such as 0.5%
Foam stiffening agent	3-5%, such as 4%
Water absorbent	5-9%, such as 7%
Coloring agents	0.5-2%, such as 1.5%

The polyether polyol may be polypropylene glycol. The polymeric polyol may be a trihydroxy polyether, is prepared by polymerization of glycerol with propylene oxide and ethylene oxide in the presence of a base catalyst. The polymeric polyol is preferably polyurethane resin POP 2045. Instead of the different polyols, the foam may also comprise 50-70% polyol, preferably 60-65%. All percentages are compared to total weight of the ingredients.

Open cell rigid polyurethane foams may also be made in known ways, as for instance disclosed in US5457138 or US5889067, to content of which with regard to Open cell rigid polyurethane foam formation is incorporated by reference herein.

According to the invention, the ingredients of the foam are processed at room temperature and put into a tank. The liquid is subsequently sprayed into a mould, such as a u-shaped groove, at pressure (preferably at high pressure, pressure above atmospheric pressure to ensure mixing of the ingredients) and allowed to expand in the mould. The mould is slowly moved forward, to keep adding material at the spraying point. This move is preferably a constant move, to provide a consistent foam along the length thereof. The produced foam is then cured, for instance for 24 hours, to create a stable foam. Afterwards, the foam is cut at length.

The invention further relates to an escalator cleaning head provided with at least one cleaning pad according to the invention.

The invention further relates to an escalator cleaning system, provided with at least one cleaning pad or escalator cleaning head according to the invention.

The invention will be elucidated on the basis of non-limitative exemplary embodiments shown in the following figures, wherein:

- Figure 1 schematically shows a cleaning pad according to the invention; and

- Figure 2 schematically shows a first embodiment of a cleaning head according to the invention.

Figure 1 schematically shows a cleaning pad (1) according to the invention. The pad (1) comprises a contact surface (2) comprising ridges (3) and/or grooves (4), for contacting ridges and/or grooves of an escalator or moving walkway. The pad (1) further comprises a connecting surface (5), arranged on an opposite side of the pad (1) compared to the contact surface (2), in this case the connecting surface (5) is on top, whereas the contact surface is at the bottom. The contact surface (5) is configured for connecting the cleaning pad (2) to an escalator cleaning head, wherein the connecting surface (5) is provided with coupling elements (6). The coupling elements (6) in figure 1 are embodied as recesses (6) in the connecting surface (5) of the cleaning pad (1). These coupling elements (6) preferably cooperate with complementary coupling elements on the escalator cleaning head. Alternatively, the coupling elements (6) are embodied as protrusions, and the recesses are arranged on the escalator cleaning head.

Figure 2 schematically shows a cleaning head (10) according to the invention, provided with a cleaning pad (1) as shown in figure 1. The coupling elements (6) of the pad (1) cooperate with complementary coupling elements (11), shown as protrusions (11) on the cleaning head (10). The head (10) is further provided with an attachment (12), to connect the head (10) to a handle (13) or broom (13). The head (10) fits into a saturation tub (14), that may for instance be filled with cleaning solution or water.

The features as shown in the figures are interchangeable between the embodiments, unless otherwise indicated.

Claims

An escalator or moving walk cleaning pad, comprising:

a. a contact surface including ridges and / or grooves, for contacting ledges and / or grooves of the escalator or moving walk;

b. wherein at least the contact surface of the cleaning pad is made of a single absorbent material, which material is an open cell flexible foamed material, in particular a foamed polyurethane.

A cleaning pad according to any preceding claim, wherein the pad is both absorbent and rigid, the pad having a rigidity, expressed as indentation deflection measured according to ASTMD3574, of greater than 70 pounds, especially greater than 80 pounds and preferably over 90 pounds.

A cleaning pad according to any one of the preceding claims, wherein the cleaning pad is not provided with a back layer, in particular does not have a back layer of polyethylene.

A cleaning pad according to any one of the preceding claims, wherein the density of the contact surface is more than 20 kilograms per cubic meter, in particular more than 30 kg per cubic meter, more particularly more than 40 kilograms per cubic meter, measured for example via ISO845.

A cleaning pad according to any preceding claim, wherein the indentation hardness, measured according to ISO 2439, is at least 250N at 25%, at least 350N at 40% and / or at least 800N at 65%, more especially at least 300N is at 25%, at least 400N is at 40% and / or at least 900N is at 65%.

A cleaning pad according to any one of the preceding claims, wherein the open cell flexible foam has a pore distribution of between 40 and 90 pores per inch, or per 2.54 cm, more particularly between 50 and 80 pores per inch, or per 2.54cm.

A cleaning pad according to any of the preceding claims, wherein the open cell flexible foam has a cell diameter of between 25 and 75 microns.

A cleaning pad according to any one of the preceding claims, comprising a joining surface provided on an opposite side of the cleaning pad to the contact surface for connecting the cleaning pad to an escalator cleaning head, the joining surface comprising coupling elements, preferably cooperating with complementary coupling elements on the escalator cleaning head.

A cleaning pad according to any one of the preceding claims, arranged for cleaning escalators of escalators and / or arranged for cleaning ridges and / or grooves of an escalator running surface.

A cleaning pad according to any one of the preceding claims, formed by mixing a polyisocyanate compound and a polyol compound and / or a polyamide compound and reacting the compounds, the polyisocyanate compound preferably diphenylmethane -4-4'-diisocyanate (MDI) may also contain additives such as castor oil.

A cleaning pad according to claim 10, wherein the rigidity of the pad is determined by the ratio of diisocyanate to polyol being greater than 0.25: 1, or wherein the amount of polyol is less than 4 times, preferably less than 3 times, the amount of diisocyanate by weight.

A cleaning pad according to claim 10 or 11, wherein the amount of alcohol or -OH groups of the polyol is expressed as N, the amount of polyol times N is expressed as a functional amount of polyol and wherein the ratio of functional amount of polyol to the amount of isocyanate is between is 1: 1.33 and 1.33: 1, preferably between 1: 1.25 and 1.25: 1.

13. Escalator cleaning head fitted with at least one cleaning pad

5 according to any of the preceding claims.

Escalator cleaning system, comprising at least one cleaning pad or escalator cleaning head according to one of the preceding claims