Patent Application
20090066142
The present invention relates to an upholstery, pareticlarly to an upholstery for a seat, particularly for use in vehicles. More specifically, the present invention relates to a novel passenger seat for vehicles which obviates the need for a pan or a wire frame structure. The present invention also relates to a process for producing an upholstery, particularly an upholstery for a passenger seat for use in vehicles.
Passenger seats in vehicles such as automobiles are typically fabricated from a foam, usually polyurethane material which is molded into the desired shape and covered with an appropriate trim cover. The foamed material is selected to provide passenger comfort by providing a resilient seat and the trim cover is selected to provide the desired aesthetic properties.
To meet desired safety standards, passenger seats in vehicles such as automobiles now often provide anti-submarine properties. Submarining is the term used to describe the tendency of the pelvis of a seated passenger to move forward and down during a collision. When the passenger is wearing a belt, usually a 3-point harness comprising an integrated lap and shoulder belt, this tendency can result in the seat belt strangling the passenger with fatal consequences. Accordingly, it is known in the art to design passenger seats with anti-submarine properties. These properties may be provided by rigid or semi-rigid members embedded in the seat and which provide additional pelvic support to the passenger during a collision. To function properly, these members can not move and thus, must be fixed directly or indirectly to the vehicle.
Normally the foamed material in the seat which provides passenger comfort does not simultaneously provide the necessary structural strength for the seat. This necessitates additional reinforcement of a seat to provide the degree of structural strength required to ensure proper mounting of the seat within the vehicle and proper support of anti-submarine elements. Accordingly, vehicular seats typically include a perimeter frame of metal which strengthens the seat. Further, support rails are typically mounted across the metal frame to stiffen the frame and to provide a suitable attachment point for the means used to anchor the seat to the vehicle. Conventionally, the metal frame and/or support rails are surrounded with the foam material when the seat is molded. There are many types of seat construction and rear limousine seats tend to differ from rear seats of a station wagon and both usually differ from front seats.
The requirement for such a perimeter metal frame and for support rails adds to the cost of manufacturing the seat and, more importantly, adds to the weight of a seat and the overall weight of the vehicle in which it is installed. The presence of metal frame and support rails or other components in the seat could probably hamper the eventual recycling of the seat material which is becoming increasingly important.
It is also known in the art that a passenger seat comprises a frame element molded from relatively high density, rigid foam, such as polyurethane foam, generally at a density of 35-60 g/l, vehicle anchorage means connected to the frame element, and a seat body comprising a resilient material, such as a polyurethane derived from a diphenylmethane diisocyanate-based system, fixed with respect to the frame element.
Polyurethane foams are conventional and use thereof in the automotive seating industry is well-known. Moreover, the polyurethane foam as used within the prior art is expensive at the required densities.
Therefore, it would be desirable to have a passenger seat, particularly a vehicle seat, which does not require the presence of a conventional metal frame or support rails and which has reduced weight, improved appearance and an enhanced manufacturability combined with reduced costs.
It is an object of the present invention to provide a novel upholstery and a novel passenger seat formed by such an upholstery. It is another object of the present invention to provide a novel method of manufacturing an upholstery and an appropriate passenger seat.
Accordingly, in one of its aspects, the present invention provides an automobile vehicle passenger seat comprising a seat body molded from EPP-foam, the EPP-foam having an average density between 30 and 60 g/l; vehicle anchorage means connected to the seat body for anchoring the seat to the automobile vehicle; and a trim cover.
EPP-foam can be manufactured between 30-120 g/l, but a density between 30 and 60 g/l usually already guarantees an adequate stability.
In one possible embodiment of the passenger seat, the passenger seat further comprises at least one pelvic support element embedded in the seat body. It is possible that the pelvic support and the seat body are integrally molded as a unitary element.
In another possible embodiment of the present invention, the seat body of the passenger seat comprises a whole anti-submarine zone, the seat body and the anti-submarine zone are integrally molded as a unitary element. It is known in the art to design passenger seats with anti-submarine properties. These properties may be provided by rigid or semirigid members which provide additional pelvic support to the passenger during a collision. As is known by those skilled in the art, the pelvic support elements may be rigid hollow plastic or metal members. By providing a pelvic support element or even a whole anti-submarine zone which is integrally molded with the seat body as a unitary element, submarining of passengers can be easily reduced without need of additional elements which have to be placed accurately when molding the seat body. Therefore, costs and manufacturing time can be saved.
Moreover, in another embodiment of the passenger seat according to the present invention, the trim cover is attached to the seat body by means of suitable retainer engaging an undercut trench molded into the seat body. It is possible that the retainer is formed as an extruded plastic channel sew to the trim cover. There are further suitable mechanical retainers like hook and loop connection elements.
In still another embodiment of the passenger seat according to the present invention the vehicle anchorage means includes an anchor portion to engage a portion of the automobile vehicle and an attachment portion inmolded in the seat body. It is possible that the attachment portion inmolded in the seat body comprises two S-shaped arms each connected to a different end of the attachment portion.
Furthermore, it is possible that the seat body is appropriately modified with coring or trenches for local stiffness and weight reduction.
It is possible that the seat body is covered on its upper surface by a further foamed material which is softer than the EPP-foam used for the seat body in order to further enhance the comfort. Such a layer of foamed material would be placed between the trim cover and the seat body. It is also possible that such a soft layer is part of the trim cover. Such a compliant layer can be made of PU with a typical PU foam density between 42 and 50 g/l. This layer is usually significantly thinner than the seat body.
In another of the aspects of the present invention, the present invention provides an upholstery for use in an automobile vehicle, particularly for a passenger seat. The upholstery is composed of and molded from EPP-foam, the EPP-foam having an average density between 30 and 60 g/l.
In terms of the present invention, the upholstery has traits of a body material usable for any kind of cushion.
It is possible that the upholstery is formed as a seat body and connected with vehicle anchorage means for anchoring said seat body to the automobile vehicle.
The upholstery can also be formed as a head restraint or an armrest and connected with anchorage means for anchoring the head restraint or the armrest to a passenger seat.
In a further embodiment of the upholstery according to the present invention, an undercut trench is molded into the upholstery intended to be engaged by fasteners of a trim cover. The upholstery should be understood within the context of the present invention as an EPP sub-structure of any suitable cushion.
In another of its aspects, the present invention provides a process for producing an upholstery in a mold comprising a first mold half and a second mold half engageable to define a mold cavity, the process comprising the steps of:
It is possible that the process of the present invention further comprises the step of molding an undercut trench into the upholstery usable to attach a trim cover to the upholstery.
Possibly, the process of the present invention comprises the further step of applying a trim cover to the upholstery.
In a further embodiment of the process of the present invention, the upholstery is formed as a seat body for a passenger seat.
In another embodiment, the process of the present invention comprises the further step of integrally molding at least one pelvic support element with the seat body.
The use of expanded polypropylene (EPP) has several properties which are advantageous with respect to polyurethane or other foams usually used. EPP has a relatively light weight with simultaneous high tear and tensile strength. Furthermore, EPP has quite a good temperature stability from −40 to +110° C. EPP has good energy absorption characteristics and resiliency. Due to its closed cell structure, EPP has no or very low water absorption.
Moreover, EPP can be considered as nearly 100% recyclable and physiologically safe as well as cadmium-free.
Polyurethane is in contrast to EPP quite expensive. EPP can be molded in densities from 30 to 120 g/l and can have local density increases to enhance structural stability as necessary. EPP, as a compliant material, is inherently more comfortable than rigid material and can be modified on the upper surface, the so-called A-surface with coring or trenches to further enhance the comfort by a local stiffness reduction and weight reduction. Generally, a contoured surface that matches a human or dummy bottom form is more comfortable than the same surface without contour. EPP can be contoured. Also, the coring or trenches allow a locally softer area. Ventilation can potentially be added by providing appropriate holes, trenches or other means.
It is possible to use 30 to 40 g/l of EPP when molding an upholstery as it is provided by the present invention. At 30 to 40 g/l, EPP is lighter than the foam usually used. EPP can already be used of a density of 30 g/l while the use of PU requires generally at least a density of 50 g/l. At 30 g/l EPP weights less than PU at 50 g/l. Coring of the EPP further reduces weight. As already stated, the structural properties of EPP may obviate the need for a pan or a wire frame structure or allow minimization of metallic structural components. The ability to mold an undercut trench around the lower surface perimeter dramatically improves the trimout appearance and reduces trim time. In estimates of weight savings during the quotation process, it is possible to save about 1.5 kg over a wire frame which is currently used and about 4 kg over a steel cushion pan. The comfort can further be optimised by contouring the upper surface made by EPP to match an offset of a dummy bottom form. Attachment to a vehicle is allowed by the ability of in-molding structural components into the EPP.
Further features and embodiments of the invention will become apparent from the description and the accompanying drawings.
For purposes of clarity, the present cushion refers to an abstract example of a passenger seat cushion. However, the process and the upholstery of the present invention may operate with a wide variety of types of applications including head restraints, seat backs and armrests.
It should be understood that while the invention is described in terms of a specific seat cushion, that the invention has applications in a variety of applications such as seat backs, head restraints, and armrests. It is intended that the upholstery as used in the specification and claims be reached to cover any application unless the context requires otherwise. Therefore, the upholstery and the seat body as described in the specification and claims can also be used outside of the automotive technology in many other types of seating.
The invention is schematically illustrated in the drawings by way of an example embodiment and is explained in detail with reference to the drawings. It is understood that the description is no way limiting for the scope of the present invention and is merely an illustration of a preferred embodiment of the invention.
In the drawings,
A trim cover and an intermediate layer of smooth foam have still to be attached to the seat bodies 10 and 100 for completing comfort quality. Polyurethane foam, having a density between 42 and 50 g/l, can be used as smooth foam for the intermediate layer.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2006/002129 | 3/8/2006 | WO | 00 | 5/28/2008 |
| Number | Date | Country | |
|---|---|---|---|
| 60666490 | Mar 2005 | US |
