SEALING STRIP

Abstract: A shaped strip for covering the edges of motorvehicle openings has a portion (1,2) suitable to be mechanically anchored to the edges of said opening and is constituted by a mass provided with cells of plastic material embedding in said cells an elastomeric material.

Description: SHAPED ARTICLE The present invention refers to a shaped article particularly for covering the edges of vehicle openings, in particular of motorvehicle openings, able to firmly anchoring itself to the edges of said openings and to guarantee a seal when said openings are occupied by the element inserted into them, as for example a door, glass and the like. Different types of shaped articles for covering the edges of motorvehicle openings are known; said types of shaped articles differ from one another for the type of motorvehicle or for the type of opening into which they must be inserted. Although differing from one another, the various types of known shaped articles for covering edges of vehicle openings all comprise a first portion which is necessary for being anchored to the edges of the opening and a second portion which must provide a seal with the element of the motorvehicle to be inserted into the opening and being apt to close it. The two portions into which a shaped article for covering the edges of motorvehicle openings can be ideally divided, accomplish different functions and therefore the properties of said portions must be different. More particularly, whilst the above cited second portion, having to accomplish a sealing function, must be elastically deformable in the highest degree, the first portion, entrusted with the function of ensuring a mechanical anchorage, must be greatly rigid when installed, but it must also be permanently deformable in order to be able to adapt itself to any shape of the opening contour. In the known shaped articles for covering the edges of motorvehicle openings, the first portion has generally a U shaped section and consists of elastomeric material, said first portion is provided with an embedded sheet iron having notches, said sheet iron with its presence confers to the second portion a rigidity and a permanent bending deformation at points of the notched sheet iron in order to permit the shaped article to follow any contour of a motorvehicle opening. It is evident that from the presence of two elements so different from each other in the first portion of a shaped article for covering the edges of motorvehicle openings, great problems arise which cannot be solved by the shaped articles of known type. A first problem is to guarantee a perfect bond between the sheet iron and the elastomeric material embedding it, in order not to reach, during the permanent deformation said portion or strip the separation of said two elements from each other and therefore the breaking of the shaped article. A second problem is connected to the necessity of having a smooth surface also for the said first portion of the shaped article without having to resort to great thicknesses for it. A third problem is due to the high weight of the shaped article due to the presence of a metallic element, as the sheet iron which owing to a cause beyond control results to be heavy for the nature of the material constituting it. A fourth problem is due to the necessity that no looseness occurs in the course of the time in the connection between the shaped article and the edges of the motor vehicle opening due to a failing of the configuration of the sheet iron under the action of the fatique stresses due to the continuous bumps that take place when the element which closes the opening, for example a door, is placed into contact with and drawn away from said opening. The known shaped articles for covering sides of motorvehicle openings as previously said, are not able to solve the above mentioned problems. The present invention aims to solve the unsolved problems in the shaped articles field, by means of a shaped article which has one portion apt to assure the mechanical anchorage with the edges of a motorvehicle opening, which is light, which has a small thickness, which has a very smooth outer surface, which has no problems in getting deformed permanently to follow any path of the contour of an opening even if said path has zones with very small bending radii and which guarantees in the course of even a very long time a sure and constant seal with the edges of the motorvehicle opening. An object of the present invention is a shaped article for covering vehicle openings, in particular motorvehicle openings, of the type comprising a first generically U-shaped portion, suitable for being anchored to the edge of the opening, and a second portion having a sealing function, characterized by the fact that the first portion is constituted by a compound of plastic and elastomeric material whilst the second portion is completely of elastomeric material. The present invention will be better understood by the following detailed description made by way of non-limiting example with reference to the figure of the enclosed sheet of drawing, which represents a section. view of a particular shaped article according to the present invention. In its more general aspects, a shaped article comprises at least a first portion, suitable to guarantee the anchorage to the edges of a motorvehicle opening, made of a compound of plastic and elastomeric material and having generally in section perpendicular to its own greater development a U shape, and a second portion made completely of elastomeric material suitable to guarantee the seal in the area of contact between the edges of the opening and the motorvehicle element (door, glass etc.) suitable to close the opening itself. More particularly, according to its more general aspects, the compound of elastomeric material and of plastic material forming the first portion of the shaped article is a compound based on a styrene polymer EPDM terpolymer, natural rubber and phenolic resin. The essential characteristics according to the present invention, which can be obtained by means of the above reported compound, is that of having the shaped article constituted by a mass provided with cells of plastic material enclosing in said cells an elastomeric material. In this way the shaped article results ideally constituted by a plurality of double layers as explained hereinafter. Among the various possible compounds for the formation of the first portion of the shaped article having as base the above reported substances, the compound reported herebelow is particularly suitable, where the components are expressed as parts by weight: natural rubber 15 parts by weight EPDM of high unsaturation 20 n II II SBR polymer of high styrene 65 II content phenolic resin 12 parts by weight zinc oxide II It II stearin 1 part " " alkylate oil 25 parts " I' carbon black N 550 85 t II calcium oxide 12 " " II sulphur 5 11 1! ll accelerators 1.3 " " II tellurium diethyldithiocarb- o.4 " <RTI ID=5.8> 1l II retardant amate o.2 " " ll The above reported compound by which the portion of the shaped article suitable to act as an element for mechanical anchoring the shaped article on the edges of a vehicle opening, is#produced by extrusion and is able to originate with the extrusion and after the vulcanization of the elastomeric material present therein, the particular structure in the form of a mass provided with cells, previously described. The above reported compound after extrusion and vulcanization of the elastomeric material has in cold conditions, and in general at the temperatures encountered in the field of strips for cars and i.e. at temperatures not higher than 9oC an elastic behaviour, whilst at higher temperatures,the cross-linked compound in question is plastically deformable, i.e. after having been subjected to stresses, said compound gets deformed permanently and after cooling, the imposed deformation is stabilized and the properties of elastic deformation are recovered. The figure of the enclosed sheet of drawing represents a shaped article according to the present invention. Said shaped article is suitable for covering the edges of a motorvehicle opening apt to receive- the edge of a sliding glass, as for example the opening present in a door for motorvehicles. As shown in the figure, the shaped article comprises two parts 1 and 2 having in the section perpendicular to their greater development a substantially U shape, said parts 1, 2 are parallel to each other and have a specular shape with respect to the plane of symmetry of the shaped article that in the figure is shown by the dash and dot line 3. The parts 1 and 2 form together the first portion of the strip. Each part 1 and 2 has therefore two flanges 4 and 5 and a web 6. In correspondence of the flange 5 there is a rib 7 projecting toward the cavity of the U shape and more particularly the rib 7 is born or carried by the flange 5. The two parts 1 and 2 are connected to each other by a band 8 which connects said parts 1 and 2 to each other in correspondence of the ends of the flanges 5 and moreover forms ribs 9 on the ends of the flanges 5 projecting toward the flanges 4 of said parts 1 and 2. The two parts 1 and 2 are formed by the compound of elastomeric material and plastic material previously described, while the band 8 is completely of elastomeric material of a type per se known to a technician of the field for being used for strips for covering the edges of motorvehicle openings and of which a formula will be given hereinafter by way of example. From the lateral end of the band 8, where this latter joins with the ends of the flanges 5 of the parts 1 and 2, strips lo depart which are in direct contact with the sidewalls of the flanges 5. Said strips lo have in correspondence of the zones where they are near the web 6 of the parts 1 and 2, fins 11 facing the one to the other. Moreover, a flocking can occur in correspondence of the face 12 of the band 8 and of the surfaces 13 of the fins 11. The parts 8 to 11 form the second portion. As previously said, the band 8 is of elastomericmaterial of a type known per se for being used in strips for covering the edges of motorvehicle openings and the ribs 9, the strips lo and the fins 11 are of the same elastomeric material. Now, by way of example a compound of elastomeric material for the formation of the just cited elements 8, 9, lo and 11 is given below. EXAMPLE EPDM loo parts by weight zinc oxide 5 " " " stearin 1 part IV " carbon black N 550 llo parts " " paraffinic oil 45 " " " accelerators 2.5 " " " sulphur 1.6 " " VI calcium oxide 6 " " " For the manufacture of the just described shaped article and in. general for the manufacture of all shaped articles lying within the most general idea of solution according to the present invention, the strip is produced by contemporaneous extrusion of the two portions 4 to 7 and 8 to 13 of the shaped article with a single extrusion head and by subsequent vulcanization of the elastomeric material of the shaped article in a manner known per se to a technician of the field. From the previous description it is easy to understand how by means of a shaped article according to the present invention the proposed aims are achieved. In fact, the elimination in a shaped article for covering the edges of motorvehicle openings of the metallic insert embedded in the body of elastomeric material of that portion of the strips whose function is to ensure the mechanical connection of the shaped article to the edges of the motorvehicle opening, permits first of all to make the shaped article on its whole with light weight since said metallic insert has a weight that cannot be disregarded, firstly for the nature of the material constituting it and secondly for the necessity of conferring to said metallic insert a certain thickness in order to have a rigidity sufficient to guarantee in the course of even a long time the anchorage of the shaped article to the edges of the motorvehicle opening. The elimination of the metallic insert in that portion of the shaped article suitable to guarantee the mechanical anchorage is made possible by the fact that the portion apt to guarantee said mechanical anchorage has, as previously described, a structure formed by a plastic material mass provided with cells, said cells being filled with elastomeric material. This is obtained by mixing both the plastic material mass and the elastomeric material before extruding them through a single die. This structure has a great rigidity accompanied by a great elasticity when the strip is installed, as it clearly appears from the consideration described below. The presence of a plastic material mass provided with cells, said cells being filled with elastomeric material corresponds ideally to a structure formed by a plural ity of double layers placed side by side. As double layer it is understood a structure formed by two thin sheets of rigid material kept far from one another by a filler. Such structure permits to have a great rigidity to the bending stresses since in each double layer the thin sheets of plastic material, lying at a certain distance from the neutral axis of the structure of which said thin sheets are a part, are subjected under bending action to great stresses in direction perpendicular to their thickness. Consequently, in this way a very good exploitation of the characteristics of the material constituting said layers is obtained. Moreover, the presence of elastomeric material as a material acting as a spacer in the double layers structure permits to have a great elasticity for said double layers since the elastomeric material being capable of storing a great deformation energy is able to return said energy when the stress that has produced the deformation has stopped acting and therefore to restore its original configuration. In addition to the just explained properties the double layers structure forming that portion of the strip entrusted with the function of ensuring the mechanical anchorage has the characteristic of getting deformed firmly when heated beyond a predetermined temperature and subjected to deformation and of maintaining the deformation given to it after the subsequent cooling, the whole accompanied by the recovery of the rigidity and elasticity properties previously described, also in the new deformed configuration assumed after heating. In order to understand how it is possible to obtain a permanent deformation by means of the heating at a temperature higher than a given value, we report the following considerations. By heating the shaped article beyond a given temper ature it is possible to place the plastic material mass provided with cells of the shaped article in a plastic condition of the plastic material itself, i.e. in a condition in which it does not offer a restistance to stresses. It follows that subjecting the shaped article to deform ation when the plastic material mass provided with cells is at a plastic state, the shape of said mass can be modified, so that after cooling a stabilization of the new plastic material mass is obtained. From one side this produces the maintaining of the deformed shape of the shaped article and from the other the recovery by the shaped article in deformed conditions of the rigidity and elasticity properties previously explained. In this way it is possible to confer to the portion of shaped article entrusted with the function of en suring the mechanical connection of the shaped article itself to the edges of the motorvehicle opening a very thin thickness and to have the surface of said portion of shaped article very smooth. This is impossible with shaped articles of known type where the presence of the metallic insert did not permit the use of thin thicknesses and left a trace on the outer surface of the embedded metallic insert. At last, the elimination of the insert of metallic material in a shaped article for covering the edges of motorvehicle openings avoids obviously all the adhesion problems between elements of so different nature and therefore consequent risks of separation between said elements and the possibility of deformations of the strip under fatique stresses which can alter in the course of time the quality of the mechanical anchorage of the strip to the edges of the motorvehicle opening. Although a particular embodiment of a strip according to the present invention has been illustrated and described, it is understood that the invention includes in its scope any other alternative embodiment accessible to a technician of the field.

Claims: Claims 1. Shaped article particularly for covering the edges of vehicle openings, in particular motorvehicle openings, of the type comprising a first generically U-shaped portion Cl, 2) suitable to be anchored to the edge of the opening, and a second portion (8 to 13) having a sealing function, characterized by the fact that the first portion (1, 2) is constituted by a compound of plastic and elastomeric material whilst the second portion (8'to 13) is completely constituted of elastomeric material. 2. Shaped article according to claim 1, characterized by the fact that the compound of plastic and elastomeric material forming the first portion (1, 2) is a compound based on a styrene polymer, an EPDM terpolymer, natural rubber and phenolic resin. 3. Shaped article according to anyone of claims 1 and 2, characterized by the fact that the material forming the first portion (1, 2) has a structure formed by a mass provided with cells of plastic material embedding in said cells the elastomeric material. 4. Shaped article according to anyone of the preceding claims, characterized by the fact that the first portion comprises a pair of parts (1, 2) of a compound of plastic and elastomeric material each having the shape of an U in transversal section, said parts (1,2) being placed side by side and parallel one to the other, mutually connected in correspondence of the ends of flanges (5) facing each other by means of the second portion which comprises a band (8) of elastomeric material, fins (ill) of elastomeric material facing each other and projecting from the web (6) of the U-shape and that a projection (4) is present in# the inside of each U-shape.

Inventors: PERINI, VALERIO
Applicants: SMAE-SOCIETA' MERIDIONALE ACCESSORI ELASTOMERICI S.P.A
Application year: 1981
Main classification: E06B7
IPC codes: E06B7, B60J10