SOUNDPROOFING ELEMENT FOR ELASTIC

Abstract

The soundproofing element (EAR) is applied to separate the terminal portions of two overlapping and adjacent elastic sheets (LM) from an elastic (FM) and comprises a metal plate (10) covered by a coating (20) in thermoplastic polyamide-11 resin and includes an intermediate projection (12) that fits and is retained in a corresponding hole (F) provided in the terminal portion of the elastic sheet (LM) against which the soundproofing element (EAR) rests and is retained.

Description

SOUNDPROOFING ELEMENT FOR ELASTIC FIELD OF INVENTION The present invention relates, in the form of a utility model, to an element to be positioned between the leaves of an elastic band usually applied in the suspension of vehicles and rolling stock, normally cargo or passenger transport vehicles, to reduce or even eliminate the noise caused by the attraction movement between the adjacent leaves of an elastic band, when the suspension is working while the vehicle is rolling. PREVIOUS TECHNIQUE Elastics applied to rolling vehicles are known in the art, each comprising a set of elastic sheets with equal or different lengths, superimposed, which flex together, reacting to the imposed loads. These widely used leaf springs have the drawback of producing loud and unpleasant noises when the adjacent leaf springs of each spring move against each other as they flex under the varying loads imposed by the vehicle's movement. This problem is particularly unpleasant for vehicle passengers. According to one of the known construction solutions for these noise-reduction elements, each one consists of a plate or sheet, generally rectangular and / or circular, made of a polymeric and / or rubber composite material, with or without reinforcing additives in its composition. Its width is adjusted to the width of the sheet bundles, and its length, in the longitudinal direction of the bundle, is sufficient to prevent direct contact between the end portions of adjacent sheets in the elastic bundle. Each element incorporates at least one protrusion, which fits into a corresponding hole provided in the adjacent elastic sheet of each pair of sheets to be separated by the sound-reducing element, ensuring the correct positioning of the element within the elastic. These sound-absorbing elements, made of a polymeric material and / or rubber compound, have a limited lifespan, as the material is lost or worn down due to workload and / or friction, until operational failure occurs. This failure can cause the sound-absorbing element to detach from the elastic band or shift between the leaves, towards the center of the elastic bands, which can cause premature fracture. In both of these failures, the sound-absorbing element loses its function. In another known construction of the soundproofing element, each one is formed by a plate or 77LLLn / L7n7 / E / YIAI A metallic sheet incorporating, on its upper face, by adhesion, vulcanization, or other suitable means, a layer of composite rubber and, on its lower face, at least one lower positioning projection, also generally metallic, for example, a set screw, and which is coupled and fixed in a corresponding hole provided in the lower elastic leaf of each pair of leaves to be separated by the soundproofing element. This composite element also has a width adjusted to the width of the elastic and a longitudinal extension just sufficient to prevent direct contact between the end portions of two adjacent elastic leaves of the elastic. These elements, made of sheet metal with a rubber pad, also have a limited lifespan due to frictional wear and the workload to which the pad is subjected. Furthermore, these rubber-padded elements are mounted to the elastic band, usually using screws (bolts) and nuts, which requires longer production times and increases product costs compared to polymeric sound-absorbing elements. Another known construction is described in patent PI0503283-0. In this case, each sound-absorbing element comprises a rectangular steel sheet of reduced thickness, with a width and length corresponding to the two adjacent leaves of the elastic band, between which it will be mounted. Each sound-absorbing element has at least its upper and lower end portions coated with a layer of elastomeric material, preferably vulcanized rubber, but which can be made of different synthetic or natural materials. This sound-absorbing element can take the form of a smooth metal sheet, held in position on the elastic band by means of a conventional pin or a central rod that passes through all the leaves, and also by the usual retaining clamps provided on the elastic band. Furthermore, the steel sheet can include, on one face, embossed projections in the form of ribs and, on the opposite face, corresponding cavities. This previous construction, in addition to suffering from the same deficiencies as the metal sheet with rubber pad, suggests the use of steel sheets that extend across the entire length of the elastic sheets between which it is mounted, substantially increasing the cost of manufacturing the elastic and unnecessarily increasing its final weight. BRIEF DESCRIPTION OF THE INVENTION Due to the shortcomings of known solutions, as explained above, the present invention aims to provide a soundproofing element of simple construction, relatively low cost, easy and safe assembly on an elastic band, and which has a longer service life in relation to known construction solutions. 77LLLn / L7n7 / E / YIAI BRIEF DESCRIPTION OF THE DRAWINGS The soundproofing element of this document will be described below with reference to the attached drawings, in which: Figure 1 represents a side elevation view of one of the terminal portions of a typical elastic band, provided with a soundproofing element of the invention between the ends of each two adjacent leaves; Figure 2 represents an enlarged, symmetrical perspective view, illustrating a terminal portion of an elastic sheet and the corresponding soundproofing element, according to a first embodiment to be mounted and fixed on the aforementioned elastic sheet; Figure 3 represents an symmetrical perspective view of the soundproofing element, according to the first embodiment illustrated in Figure 2; Figure 4 represents a cross-sectional view of the soundproofing element, taken from line IV-IV in Figure 3 and when mounted between two adjacent sheets of elastic, illustrated in cross-section; Figure 5 represents an symmetrical perspective view of the soundproofing element according to a second embodiment; and Figure 6 represents a cross-sectional view of the soundproofing element in its second embodiment, where the cut is taken according to VI-VI in Figure 5 and mounted between two adjacent elastic sheets, illustrated in cross-section. DETAILED DESCRIPTION OF THE INVENTION As explained and illustrated in the accompanying drawings, the sound-damping element EAR is positioned between the end portions of two LM leaf springs of an FM leaf spring, which is commonly used in vehicle and rolling stock suspensions and consists of a set of LM leaf springs. In the illustrated embodiment, the LM leaf springs are of different lengths, although it is possible to use LM leaf springs of the same length in the manufacture of an FM leaf spring. The LM leaf springs are mounted overlapping each other, with or without the provision of ER retaining elements, which serve an alignment function known in the art. It should be understood that the expression elastic leaf defines not only an elastic leaf that operates as a suspension leaf, but also a possible safety elastic leaf, arranged in the lower region of the elastic and which does not function as a suspension leaf, but as an additional safety element in case of breakage of the elastic, which may comprise one or multiple suspension elastic leaves. 77LLLn / L7n7 / E / YIAI According to the present invention, each soundproofing element EAR comprises a metal plate 10, in steel or any suitable alloy, of variable contour, polygonal, circular or elliptical, with a maximum width adjusted to the total width of the elastic FM, provided or not with its retention elements ER, and which has a longitudinal extension approximately equal to the width and sufficient to prevent direct contact between the overlapping terminal portions of the two adjacent elastic sheets LM. In the two illustrated embodiments, each metal plate 10 has a thickness less than the thickness of the LM elastic sheets, generally less than half the thickness of the adjacent LM elastic sheets, each metal plate 10 being covered by a coating 20 in the form of a thermoplastic resin layer known as polyamide-11, the thickness of the coating 20 ranging from 0.01mm to 2.00mm, depending on the dimensional characteristics of the LM elastic sheets of the FM elastic to which the soundproofing element EAR will be applied. Coating 20 is defined by the application, by immersion or any other suitable process, of the thermoplastic resin defined by polyamide-11. This allows for the creation of a soundproofing element that can be used on any FM elastic type, is easy to obtain and install, has a competitive cost, and offers superior durability compared to currently available solutions. Coating 20 is partially illustrated in the EAR soundproofing element (see Figures 2, 3, and 5). As illustrated in Figures 3 and 4, the soundproofing element EAR can be defined, in a first embodiment, by a metal plate 10, with the width, length and thickness dimensions defined above and includes an intermediate projection 12 which, in the illustrated embodiments, is defined by an intermediate bend 11, said intermediate projection 12 projecting to be housed and fixed, against displacement, in a corresponding hole F provided in the terminal portion of the elastic sheet LM against which the soundproofing element EAR rests and is fixed. In the example of figures 3 and 4, the intermediate bend 11 results in an intermediate protrusion 12 defined by a pair of parallel ribs 12a, separated from each other and arranged in the longitudinal direction of the elastic FM, which enter the hole F of the terminal portion of a respective elastic sheet LM, ensuring the correct and safe positioning of the soundproofing element EAR in the elastic FM. Figures 5 and 6 illustrate a second embodiment of the soundproofing element EAR, which has the same characteristics described above in relation to the first embodiment illustrated in Figures 3 and 4 and which has the same reference numbers. However, in the second embodiment, the metal plate 10 incorporates, on each longitudinal edge, a lateral fin 15 that rests against an adjacent lateral edge of a sheet of 77LLLn / L7n7 / E / YIAI elastic LM immediately adjacent, above or below, on the elastic FM. In Figure 6, only the seating of the side fins 15 of the metal plate 10 against the side edge of the immediately above elastic LM sheet is shown. However, it should be understood that the metal plate 10 can be mounted in an inverted position relative to that illustrated in Figure 6, with its side fins 15 supported against the opposite side edges of an immediately below LM sheet. Thus, in the now proposed construction, in which the metal plate 10 incorporates the side fins 15, the retaining elements ER, illustrated in Figure 1, can be totally or partially omitted from the elastic FM. In both the first and second embodiments, preferably the entire metal plate 10, including the intermediate projection 12 and the side fins 15, is covered by the polyamide-11 coating 20, avoiding any direct metallic contact between the soundproofing element itself and the two adjacent LM elastic sheets. Although only two ways of making the soundproofing element have been described, it is possible to introduce changes in the shape and arrangement of its components, without departing from the proposed construction concept.

Claims

1. - Soundproofing element for elastics of the type formed by a set of elastic leaves (LM) mounted superimposed and the terminal portions of two adjacent elastic leaves (LM) being separated by a respective soundproofing element (EAR), characterized in that it comprises a metal plate (10), with the width adjusted to the total width of the elastic (FM) and with a length that prevents direct contact between the superimposed terminal portions of the two adjacent elastic leaves (LM), said metal plate (10) is covered by a coating (20) in thermoplastic polyamide-11 resin and incorporates an intermediate projection (12) that fits and is retained in a corresponding hole (F) provided in the terminal portion of the elastic leaf (LM) against which the soundproofing element (EAR) rests and is retained.

2. - Soundproofing element, according to claim 1, characterized in that the coating (20) is defined by a layer of polyamide-11 resin, with a thickness of 0.01mm to 2.00mm. 3.- Soundproofing element, according to any of claims 1 or 2, characterized in that the metal plate (10) has a thickness less than the thickness of the elastic sheets (LM).

4. - Soundproofing element, according to any of claims 1, 2 or 3, characterized in that the intermediate projection (12) of the metal plate (10) is defined by an intermediate bend (11) in the latter. 5 - Soundproofing element, according to claim 4, characterized in that the intermediate projection (12), formed by the intermediate fold (11), is defined by a pair of parallel ribs (12a), separated from each other, arranged in the longitudinal direction of the elastic (FM) and which can be housed in the hole (F) of the terminal portion of a respective elastic sheet (LM).

6. - Soundproofing element, according to any of claims 1 to 5, characterized in that the metal plate (10) incorporates, on each longitudinal edge, a lateral fin (15) that rests against an adjacent lateral edge of the elastic sheet (LM) immediately adjacent, upper or lower, on the elastic (FM).

7. - Soundproofing element, according to any of claims 1 to 6, characterized in that the entire metal plate (10), including the intermediate projection (12) and the entire upper side fin (15), is covered with a coating (20) in polyamide-11.