METHOD FOR PREVENTING SLIPPERINESS OF A ROADWAY OR EQUIVALENT BY MEANS OF A FRICTION MATERIAL OR FRICTION SURFACE

Description

[0001] The present invention relates to a method as defined in the preamble of claim 1 for preventing slipperiness of a roadway or equivalent. Such a method is known from any of DE-A-3423354 or DE-A-3002328 or SU-A-1701774.

[0002] The methods used to eliminate slipperiness are based on causing friction materials, including organic or inorganic materials such as sand, gravel, crushed aggregate, expanded clay aggregate, peat, wood chips, sawdust, etc., to adhere to the ground with the aid of water added to it. An adherence phenomenon or "sticking" occurs when the surface temperature of a passage or traffic area, such as a road, is below +0°C and friction material spread onto the surface by a dispensing apparatus freezes fast on the ground (road or the like).

[0003] By "gluing" the friction material to the ground surface, it is possible to use friction material of finer composition (of smaller granular size) and smaller layer thicknesses, thus allowing a larger working area than before to be treated with one filling with the same amount of raw material. Friction material particles sticking to the surface as if "glued" are not carried away with the air currents generated by vehicles, nor are they moved aside by being stuck to the tire treads, nor do they flow down to the bottom of ruts; instead, they remain in place, with the result that their effective service life is longer, allowing the number of treatments to be reduced. Using the "gluing" method, the same results can be achieved by using lighter friction materials, e.g. expanded clay aggregate or organic materials (sawdust, wood chips, etc.).

[0004] Patent specification DE 3732657 discloses a method for improving the friction of an ice surface, using a granular, non-water-soluble friction material, especially sand. The friction material is moistened and heated before being spread on the road surface. However, moistening and heating the friction material before application is a fairly difficult business and requires additional equipment, which means additional costs. Heating the friction material also adds to the costs.

[0005] Patent specification FI 105353 discloses a method for sanding a road or equivalent, in which method the sand is spread from a moving vehicle over a desired width, thus producing a sanded road. The sand is caused to adhere to the icy ground by heating the sand particles by means of runners moving behind on the sanded area, which produce a friction and pressure effect on the ground after the sand has been spread. The sand is thus heated and pressed into the ice. The method according to this specification also requires additional equipment for heating the sand, which again increases the costs.

[0006] The object of the invention is to eliminate the drawbacks of prior art and achieve a new type of method and apparatus for preventing slipperiness. The invention is based on the idea of spreading friction material directly on the ground to form friction areas, such as patches or stripes, which makes it possible to create friction areas of desired form.

[0007] An embodiment of the invention is based on the principle of spreading friction material as such onto the ground and applying the liquid needed to moisten it to the ground separately from the same vehicle or machine. The liquid can be spread on the ground in patches or equivalent of desired form, thus allowing to create friction material areas of desired form. In this case, the friction material can be spread on the ground directly as such without being moistened before the spreading, thus reducing the number of work operations needed before the spreading of the friction material. The method of the invention is simple and reliable. The equipment required is also very simple.

[0008] By using patch-like or stripe-like friction material areas, it is additionally possible to save friction material and, when desirable, to control the path of movement of a vehicle running on a slippery road as it is moving on an icy surface.

[0009] The features characteristic of the method of the invention are presented in detail in the claims below.

[0010] In the following, the invention will be described in detail by the aid of a few examples with reference to the attached drawing, wherein Fig. 1 presents an apparatus according to the invention for preventing slipperiness of roadway or equivalent, fitted on a truck, and Fig. 2 presents a second apparatus according to the invention.

Example 1

[0011] The truck 2 moving on a road 1 as shown in the figure may be provided with an apparatus according to the invention for spreading a friction material, preferably in granular form, preventing slipperiness, such as sand. For this purpose, the apparatus comprises a platform on which the sand to be spread is loaded. In addition, the vehicle is provided with a liquid tank, mounted e.g. on the front side of the platform, for water/liquid to be spread on the roadway 1 in connection with the spreading of sand. The liquid tank and also the platform may be thermally insulated.

[0012] In the method of the invention, the sand is spread as such on the roadway by means of a spreading/scattering device provided in the platform, and cold friction material can be used advantageously as it fastens sooner to the road/ground.

[0013] The water/liquid is sprayed onto the surface of the roadway 1 before the spreading of the sand, by means of the liquid dispenser mounted in front of the spreading/scattering device, water/liquid being supplied into the dispenser via a pipe. The dispenser is provided with nozzles, by means of which the water/liquid can be sprayed onto the ground in a desired manner, e.g. in patches, in which case the sand will only stick to the road in the area of these patches. This reduces the amount of sand consumed in sanding. Instead of patches it is possible to use stripes etc., making it in some cases possible to influence a vehicle moving on the icy surface so as to direct it in a given direction.

[0014] When instead of sand a friction material lighter than water is used, it will not dive in consequence of momentary melting of the surrounding ice but remains buoyant in its melting pit, to be again frozen fast, thus behaving in the desired manner.

[0015] By using organic materials "glued" as friction materials, they can be brushed directly to the green areas in the spring, thus allowing savings to be achieved in cleaning and transportation costs.

[0016] The exhaust pipe of the vehicle can be provided with a by-pass 10 so arranged in conjunction with the tank and the platform that it produces lost heat for heating these if necessary. It can also be used to heat the liquid dispenser and the pipe. The driver can control the amount of heat by adjusting the by-pass flow of exhaust gas by means of a valve. The temperature of the water/liquid supplied can be optimized relative to the effects of weather and external temperature, even by cooling if necessary. When pressurized spraying is used, the water/liquid may be under-cooled before being sprayed.

Example 2

[0017] The friction material may also be spread on the ground by means of a patterned cylindrical roll/roll mat 21 as presented in Fig. 2, whose surface is provided with flutings 22 of desired form. A spreading device like this may be of a self-propelling type or it may be of a type designed to be hauled behind a vehicle/machine. The roll/roll mat may be of a tooling type, in which case the material used as friction material can be obtained entirely or partly from the ground.

[0018] It is obvious to the person skilled in the art that different embodiments of the invention are not limited to the examples described above, but that they may be varied within the scope of the claims presented below.

Claims

1. Method for preventing slipperiness of a roadway (1) or an equivalent ground surface, in which method an uneven friction surface is produced on the ground by using a friction material, characterized in that friction material is spread on certain spots on the ground so that they form friction areas at certain spots, and that said spots are of a patch-like and/or stripe-like form.

2. Method according to claim 1, characterized in that additionally to the friction material freezable liquid is spread that adheres to the ground.

3. Method according to claim 2, characterized in that the liquid is water or equivalent, with additives mixed in it so as to render it consistent, e.g. gelatinous.

4. Method according to claims 2 or 3, characterized in that pressurized spraying is used in the method and that the water/liquid may be under-cooled before being sprayed.

Ansprüche

1. Verfahren zum Verhindern von Glätte oder Schlüpfrigkeit einer Straße (1) oder einer vergleichbaren Boden-Oberfläche, wobei in diesem Verfahren durch Verwendung eines Reibungsmaterials eine unebene Reibungsoberfläche auf dem Boden erzeugt wird, dadurch gekennzeichnet, dass Reibungsmaterial auf bestimmten Punkten auf dem Boden aufgetragen wird, so dass sie Reibungsbereiche an bestimmten Punkten bilden, und dass die genannten Punkte eine fleckenartige und/oder streifenartige Form aufweisen.

2. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, dass zusätzlich zum Reibungsmaterial gefrierbare Flüssigkeit aufgetragen wird, die am Boden haftet.

3. Verfahren gemäß Anspruch 2, dadurch gekennzeichnet, dass die Flüssigkeit Wasser oder ein Äquivalent ist, das eingemischte Zusätzen aufweist, um es dickflüssig, z. B gelatinös zu machen.

4. Verfahren gemäß den Ansprüchen 2 oder 3, dadurch gekennzeichnet, dass Drucksprühen im Verfahren verwendet wird, und dass das Wasser / die Flüssigkeit unterkühlt sein kann, bevor es/sie versprüht wird.

Revendications

1. Procédé pour empêcher la glissance d'une chaussée (1) ou d'une surface de sol équivalente, dans lequel procédé, on produit une surface de frottement irrégulière sur le sol en utilisant un matériau de frottement, caractérisé en ce que le matériau de frottement est étalé sur certains points sur le sol de sorte qu'ils forment des zones de frottement sur certains points, et en ce que les points sont en forme de pièce et/ou en forme de rayure.

2. Procédé selon la revendication 1, caractérisé en ce qu'en plus du matériau de frottement, on étale un liquide qui peut être congelé qui adhère au sol.

3. Procédé selon la revendication 2, caractérisé en ce que le liquide est de l'eau ou équivalent, avec des additifs mélangés à ce dernier afin de le rendre consistant, par exemple gélatineux.

4. Procédé selon les revendications 2 ou 3, caractérisé en ce que l'on utilise une vaporisation sous pression dans le procédé et en ce que l'eau / liquide peut être super refroidi(e) avant d'être pulvérisé(s).

Drawing