Patent Application
20180072207
This application claims the priority benefit of French patent application number 16/58440, the content of which is hereby incorporated by reference in its entirety to the maximum extent allowable by law.
The present disclosure generally relates to motor vehicle seats and, more particularly, to the forming of foam upholstery of a seat element.
More and more often, it is desired to form complex foam seat elements, be it to integrate various devices or fittings therein or to have foams having different densities.
The integration of an object in foam injected in one piece may raise an issue. Indeed, conventionally, the object cannot be placed in the mold before the foam injection since, during the injection, foam might reach portions of the device and hinder its subsequent operation. This is for example true when a three-dimensional textile is desired to be integrated to obtain a ventilation effect. The injected foam will tend to fill up the cells of the 3D textile.
In the case of the forming of a seat element with foams having different densities, it is difficult to define the border between two foams from the moment that they are injected at the same time into the same mold.
An embodiment aims at providing a method of forming upholstery of a seat element by foam injection which overcomes all or part of the disadvantages of usual methods.
An embodiment provides a solution particularly adapted to the forming of upholstery made of foams having different densities.
An embodiment provides a solution particularly adapted to the integration of a device in the upholstery.
Thus, an embodiment provides a method of forming upholstery of a foam seat element comprising the steps of:
inserting, into an injection mold, a plastic film delimiting at least one first foam injection area;
injecting foam to form the upholstery in one piece, the film disappearing with the polymerization of the foam.
According to an embodiment, the film is made of a mixture of polyethylene and of starch.
According to an embodiment, the film separates the foam injection area from an object.
According to an embodiment, the object is a 3D textile layer.
According to an embodiment, the film delimits the first injection area from at least one second foam injection area in the mold.
According to an embodiment, the foam injection areas are intended for foams having different densities.
According to an embodiment, a cover is placed at the bottom of the mold before injection.
An embodiment provides upholstery of a seat element, obtained by the implementation of the above method.
An embodiment provides a motor vehicle seat element comprising at least one piece of upholstery.
An embodiment provides a motor vehicle seat comprising at least one seat element.
The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of dedicated embodiments in connection with the accompanying drawings.
For clarity, only those steps and elements which are useful to the understanding of the embodiments which will be described have been shown and will be detailed. In particular, the forming of the other seat elements, and particularly of the frame and of the cover, has not been detailed, the described embodiments being compatible with usual embodiments of such elements.
It should be noted that, in the drawings, the structural and/or functional elements common to the different embodiments may be designated with the same reference numerals and may have identical structural, dimensional, and material properties.
In the following description, when reference is made to terms qualifying absolute positions, such as terms “front”, “rear”, “top”, “bottom”, “left”, “right”, etc., or relative positions, such as terms “above”, “under”, “upper”, “lower”, etc., or to terms qualifying directions, it is referred, unless otherwise mentioned, to the orientation of the drawings or to a seat in its normal position of use. Unless otherwise specified, expressions approximately, substantially, and in the order of mean to within 10%, preferably to within 5%.
According to this embodiment, it is desired to form three foam areas having different densities. This is an arbitrary example, and other configurations may be provided.
A foam injection mold 3 is used in the form, for example, of two shells 32 and 34, defining the shape of the upholstery and assembled to each other before the injection. Mold 3 is not modified by the implementation of the described embodiments. To inject three foams M1, M2, and M3 having different densities, mold 3 comprises at least three injection nozzles 36 arranged at the level of the corresponding areas.
In a conventional embodiment, the foams are injected at the same time or with a slight delay according to the areas. A difficulty is that the interfaces between areas are difficult to clearly and reproducibly define. This issue is particularly present at the edges of the mold, and thus of the upholstery.
According to the embodiment shown in
The material of film 2 is selected on the one hand to be foam-tight during the injection but also to degrade during the polymerization of the foam.
It is, for example, a film made up of polyethylene and starch which has the specificity of disappearing when the foam polymerizes or, more specifically, of integrating to the foam.
If no film which degrades during the polymerization is used, the foam areas would remain separated and would not adhere together.
A lining material made of woven or nonwoven textile, of skin, or of a synthetic material may be arranged, before the foam injection, at the bottom of mold 3 to directly form the cover around the upholstery.
In a conventional embodiment, thermoforming layers have to be used to attach the three-dimensional textile to the upholstery. This complicates the manufacturing.
According to the embodiment illustrated in
During the foam injection, for example, by a nozzle 36, the foam is retained by film 2, which avoids filling the cells of the 3D textile.
According to an embodiment, film 2 is made of plastic, for example, of polyurethane, of linear low-density polyethylene (LLDPE), of low-density polyethylene (LDPE). According to this embodiment, film 2 remains once the element has been finished.
According to another preferred embodiment, film 2 is, as in the embodiment of
The case where plastic film 2 remains at the end of the manufacturing is assumed. A foam layer 51 is thus present at the front of the backrest. The back of layer 51 is separated from 3D textile layer 4 by film 2. The back of layer 4 is covered with a protection, for example, duffel 53. Preferably, an opening 535 for receiving a ventilation grid 55 communicating with the 3D textile is provided in layer 53.
An advantage is that it is now possible to form a seat element in one piece by foam injection, including while integrating a device inside of it. The manufacturing is considerably simplified.
Various embodiments have been described. Various alterations, modifications, and improvements will occur to those skilled in the art. In particular, the forming of the actual foam has not been discussed, the described embodiments being per se compatible with usual forming methods. Further, the practical implementation of the described embodiments is within the abilities of those skilled in the art based on the functional indications given hereabove, be it for molding techniques or for the selection of the material forming the film.
Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and the scope of the present invention. Accordingly, the foregoing description is by way of example only and is not intended to be limiting. The present invention is limited only as defined in the following claims and the equivalents thereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16/58440 | Sep 2016 | FR | national |
