Patent Application
20080309128
The invention relates to a seat insert, in particular for application in an automotive vehicle or aircraft seat. The seat insert is provided with a gas-tight covering enclosing a volume at least partly and comprising an inner surface and an outer surface. In addition the seat insert comprises a valve through which the amount of gas in the volume can be regulated. The covering comprises at least one air conditioning section provided with a perforation.
The invention relates furthermore to a seat in which one such seat insert to include all kinds of pads serving to support the occupant, particularly also lounger mats.
To avoid heat and moisture becoming trapped between the occupant and the seat supporting the occupant a cushion is known from DE 37 05 756 A1 from which a stream of air flows to cool the occupant and to remove body moisture. The cushion integrated in the seat cushion and/or backrest of the seat or configured as a separate seat pad comprises a covering consisting of two webs of fabric which enclose a volume through which air flows. The fabric webs are maintained at a constant spacing away from each other by pile threads running vertically to the fabric webs and are provided at the upper side and underside of the cushion with an elastomeric, air-tight coating. The edges of the fabric webs are hemmed air-tight. The coating at the upper side of the cushion is perforated to permit release of the air flow supplied to the cushion via a filler port. To achieve an even distribution of the air flow emerging from the cushion an air-permeable buffer layer is arranged on the perforation. The buffer layer may be formed by a non-woven, an air-permeable foam or an air-permeable cover of the seat. To prevent the cushion from being squashed it needs to be pressurized in the range of approximately 10 kPa to approximately 60 kPa. The pile threads prevent the cushion from becoming bloated when pressurized. One drawback of this known cushion was found to be that although it achieves an even distribution of the pressure when accommodating an occupant, it offers no attenuation. The cushion thus lacks adequate seating or reclining comfort.
By contrast, DE 33 06 871 A1 discloses a pad which finds application for an automotive vehicle seat comprising a foamed core made of polyurethane and an air-permeable cover layer. The cover layer can be formed either by an air-permeable cover or by a foam laminated non-woven. The foamed core features chambers in which half-shells open to the surface of the foamed core are arranged. As an alternative, flexible tubes can be foamed in place in the foamed core which are connected to ports joining the surface of the foamed core. The half-shells or tubes enable air to be extracted through the air-permeable cover layer to the outer surface of the pad to avoid heat being trapped in a seating surface formed by the pad. Integrating the half-shells or tubes in the foamed core is relatively complicated and costly to fabricate.
Furthermore DE 42 11 895 A1 discloses a seat provided with a seat insert concealed by padding. The seat insert comprises a pad member made of a porous elastic foam and a cover enclosing the pad member. Although the pad member is defined by the covering it is not connected thereto and thus has less resistance to the pressure exterted by the occupant. This results in hardenings of the seat insert being prevented in use. The covering is connected to a pressure generator by means of which the seat insert can be pressurized and depressurized.
A cover for automotive vehicle seats comprising an air-permeable section made of a woven polyamide yarn reads from EP 0 206 152 B1. Here, the cover arranged on a padding of the seats serves to allow air leaving tubes arranged in the padding to flow to the outer surface of the seat to achieve an air conditioning effect.
The invention is based on the object of sophisticating a seat insert of the aforementioned kind so that a relatively high seating and reclining comfort can now be achieved by comparatively simple and low-cost production. In addition, a seat is intended to be achieved which now ensures adequate air conditioning for a seat occupant.
This object is achieved by a seat insert having the features as set forth in claim 1 and by a seat having the features as set forth in claim 21. Further aspects of the seat insert in accordance with the invention and of the claimed seat are defined in claims 2 to 20 and 22 to 24 respectively.
The seat insert in accordance with the invention is the result of having discovered that a pad member made of an open core soft foam, positively material connected to the inner surface of the covering now provides for a relatively high seating and reclining comfort. This is because the soft foam endows the pad member with an elasticity which, for one thing produces an attenuation when supporting an occupant. For another, the open core structure of the soft foam ensures an adequate permeability of the pad member which now makes it possible to do away with, for example, air conduit tubes in the pad member as are usual in prior art. A comparatively simple and low-cost production of the seat insert is now assured.
In one preferred aspect of the seat insert in accordance with the invention the soft foam is polyurethane which can be molded hot or cold and also as block foam. To ensure a relatively high shaping compliance of the pad member in contributing towards a high seating and reclining comfort, the soft foam has a specific weight in the range of approximately 15 kg/m3 to approximately 90 kg/m3, preferably approximately 30 kg/m3 to approximately 50 kg/m3. In addition it has been discovered to be an advantage when the soft foam features a crushing strength in the range of approximately 1.5 kPa to approximately 10 kPa, preferably approximately 2.5 kPa to approximately 5.0 kPa.
It is furthermore of advantage when the pad member has a thickness in the range of approximately 3.0 mm to approximately 30.0 mm, preferably approximately 5.0 mm to approximately 15.0 mm, resulting in the seat insert being relatively thin so that it can be directly integrated in a seat or configured as a separate seat cushion.
Preferably, the perforation consists of a plurality of holes having a diameter in the range of approximately 0.1 mm to approximately 5.0 mm. The holes may be the same in diameter and arranged equispaced to permit particularly simple and low cost production. As an alternative, the holes may differ in diameter and be differingly spaced from each other to form a perforation in keeping with physiological and ergonomic requirements. The diameter and the number of holes define together with the pressure of the gas in the volume the magnitude of the flow through the seat insert which, as an example, amounts to approximately 100 l/min.
To achieve a comfort-tailored design of the seat insert it is of advantage to fabricate the pad member of a molding foam. As an alternative the pad member can be made of a block foam to achieve relatively low-cost production. Unlike block foam, molding foam offers high flexibility as to shaping the pad member, so that the seat insert, whose contour is mainly determined by the pad member, can be endowed with a design which is also pleasing in appearance. In this context, it has been discovered, it is also of advantage to interconnect the inner surface of the covering and the pad member by back foaming, i.e. positively material connected to the covering resulting from foaming the pad member to enhance flexibility in shaping the pad member and thus the contour of the seat insert.
It is of advantage when the covering is a film preferably made of polyurethane, polyamide or polyethylene. Such a film has sufficient elasticity and can be deep drawn in the foaming mold in which the pad member is foamed to permit professional backfoaming. As an alternative the covering can be a fabric provided with a gas-tight covering as is known from DE 37 05 756 A1.
In a preferred aspect of the seat insert in accordance with the invention the outer surface of the covering is provided with an air-permeable cover. The cover made of a textile fabric, for example, enhances the visual appeal of the seat insert so that the seat insert can be designed as a seat cushion which like a slip cover can be arranged on a seat. The cover is expediently configured elastic and can be laminated with a foam layer for this purpose.
It is furthermore expedient to arrange the valve replaceable on the covering to make for professional maintenance and facilitated recycling. The valve is preferably connected to a pump by which the volume is evacuated to a pre-determined vacuum or charged with gas to a predetermined pressure. When a vacuum is created in the volume which relative to ambient pressure is expediently in the range of approximately 1.0 kPa to approximately 100 kPa, preferably in the range of approximately 5.0 kPa to approximately 30 kPa air is then extracted through the seat insert as described in DE 33 06 871 A1; whereas, if a pressure is generated in the volume which relative to ambient pressure is expediently in the range of approximately 1.0 kPa to approximately 100 kPa, preferably in he range of approximately 5.0 kPa to approximately 30 kPa air is then a gas flow then occurs from the seat insert as described in DE 33 06 871 A1 resulting in air conditioning. The flow of gas, which in the simplest case is air or a gas scented for example with aromatic substances can then be heated or cooled for this purpose.
In another preferred aspect of the seat insert in accordance with the invention the volume is divided into a plurality of chambers each hermetically sealed from the other, a pad member being arranged in each chamber. In addition an air conditioning section is assigned to the each chamber so that a volume flow differing in amount and direction can flow through the chambers to result in air conditioning tailored to individual requirements.
Details and further advantages of the present invention read from the following description of a preferred example embodiment with reference to the drawing illustrating the example embodiment merely diagrammatically in which
Referring firstly to
Referring now to
The pad member 20 positively material connected to the inner surface 12 of the covering 11 is made of an open core soft foam. The soft foam is made of polyurethane and has a specific weight in the range of approximately 15 kg/m3 to approximately 90 kg/m3. In the preferred case, the specific weight is, for example, approximately 30 kg/m3. The crushing strength is in the range of approximately 1.5 kPa to approximately 10 kPa, preferably approximately 2.5 kPa to approximately 5.0 kPa.
The pad member 20 whose thickness d is in the range of approximately 3 mm to 30 mm is made of molding foam. For this purpose a film forming the covering 11 can be deep drawn in a foam mold having the contour of the seat insert 10 by means of a vacuum applied to the foam mold. After this, a reaction mixture is filled into the foam mold and the pad member 20 foamed in the foam mold such that the film and covering 11 respectively are backfoamed, the result of which is a reliable positively material connection between the film and the pad member 20. After backforming, the molding formed by the pad member 20 and the film is removed from the foam mold. When the seat insert 10 has a relatively complex shape several moldings can be joined together to form the seat insert 10. For this purpose the films of the moldings forming the covering 11 are welded together along a seam 17. In addition, the pad members 20 of the moldings can be bonded together.
When, on the other hand, the covering 11 is a coated fabric bonded to the pad member 20 by the inner surface 12, then it is expedient to additionally seal the two adjoining edge portions of the covering 11 by a tape 18.
The seat insert 10 serves to permit air conditioning for the seat occupant supported by the seat 30. For this purpose, the covering 11 features air conditioning sections 15a, 15b, 15c provided with a perforation 16. The perforation 16 is composed of a plurality of holes which depending on the particularly application have a diameter in the range of approximately 0.1 mm to approximately 5.0 mm. The perforation 16 permits a volume flow between the volume 14 and the atmosphere.
For this purpose it is necessary that either a vacuum of, for example, 50 kPa relative to the ambient pressure or a pressure of, for example, likewise 50 kPa relative to the ambient pressure exists in the volume 14. To produce the difference in pressure between the volume 14 and the atmosphere a valve 40 is arranged in the covering 11 by means of which the amount of air in the volume 14 can be regulated. The valve 40 taking the form, for example, of a variable pressure limiting throttle valve is connected to a pump 41 by which the volume is evacuated to a predetermined vacuum or pressurized to a pre-determined pressure. Depending on the diameter and number of holes of the perforation 16 and difference in pressure between the volume 14 and the atmosphere a volume flow can be set amounting to 100 l/min, for example.
When the volume 14 is pressuried in the region of the air conditioning sections 15a, 15b, 15c air flows from the seat insert 10 and through the cover 33 of the seat 30. The air flow heated or cooled as required, for example, by means of an air conditioning system of the vehicle permits avoiding heat and moisture being trapped between the seat occupant and seat 30. Comfortable air conditioning can also be achieved by a vacuum being generated in the volume 14 so that air is drawn off from the outer surface of the seat 30 through the seat insert. In addition it is possible to vary and/or direct the volume flow in the individual air conditioning sections 15a, 15b, 15c to tailor air conditioning to the individual physiological and ergonomic requirements. For this purpose the volume 14 of the seat insert 10 can be divided into a plurality of chambers each hermetically sealed from the other, connected by separate valves 40, each permitting control independently of the other.
The seat 30 as described above is characterized by the seat insert 10 creating air conditioning which is simple to manufacture at low-cost and greatly enhances seating and reclining comfort. This is to be attributed particularly to the pad member 20 made of an open core soft foam. The open core structure of the soft foam ensures, for one thing, that an amount of air sufficient for generating the desired pressure or vacuum can be stored in the volume 14 and, for another, that the seat insert 10 is sufficiently permeable for the volume flow involved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 029 062.8 | Jun 2004 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2005/052749 | 6/14/2005 | WO | 00 | 9/28/2007 |
