WO2000067529A1

WO2000067529A1 - Seat heating element

Info

Publication number: WO2000067529A1
Application number: PCT/IB2000/000550
Authority: WO
Inventors: Michel Balmisse; Jean-Luc Hamm; Jean-Marc Conrad
Original assignee: Johnson Controls-Roth S.A.
Priority date: 1999-04-30
Filing date: 2000-04-29
Publication date: 2000-11-09
Also published as: EP1049355A1; DE60000028D1; EP1049355B1; ES2165835T3; DE60000028T2; ATE208554T1; FR2792870A1; PT1049355E; FR2792870B1

Abstract

The present invention relates to a process for manufacturing a heating layer (5, 11, 13) and for insertion thereof in a seat cushion (2) between the padding and the cover. The process essentially involves producing, a dimensionally stable heating layer by connection of a coiled heating cable (16) to at least one wide-meshed permeable adhesive grid subsequently fixing said heating layer directly to the internal face of a cover then attaching the cover to a foam padding (3) by adhesion using a fixing adhesive which traverses the wide-meshed grid or grids of adhesive or by other fixing processes, the heating layer therefore matching the styling grooves (17) perferctly. The invention is more particularly applicable in the field of production of seat cushions, in particular seat cushions equipped with heating layers.

Description

SEAT HEATING ELEMENT

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns the field of the manufacture of seat cushions, in particular base or back cushions equipped with heating layers, and relates to a process for producing a heating layer of this type and for insertion thereof in a seat cushion between the padding and the cover.

2. Description of the Prior Art

At present, heating layers intended for seat cushions generally consist of electric heating wiring which adheres to a sheet or between two thin sheets of polyurethane foam or similar material. This complex is coated on one of its faces with an adhesive for sticking it to the cover. However, a complex of this type is too thick to accept the deep deformations required for producing styling grooves. Moreover, the thickness of the complex obtained and the layers of adhesive impair the permeability of the cushion.

Furthermore, the design of the complex is expensive and the production process adopted is incompatible with lining by adhesion, whether of the type described in FR-A-2

731 380 or another type, because said complex is not perforated and therefore prevents the adhesive from passing through.

It is the object of the present invention to overcome these drawbacks while proposing a process for manufacturing a heating layer and for insertion thereof into a seat cushion between the padding and the cover, for obtaining heating cushions which have a relatively low cost price, are comfortable in use and are compatible with the processes of lining by adhesion and/or by in-situ foaming.

SUMMARY OF THE INVENTION To this end, the process for manufacturing a heating layer and for insertion thereof into a seat cushion between the padding and the cover essentially involves producing, in a first stage, a dimensionally stable heating layer connection of a coiled heating cable to at least one wide-meshed permeable adhesive grid, subsequently fixing said heating layer directly to the internal face of a cover, then attaching the cover to a foam padding by adhesion using a fixing adhesive which traverses the wide-meshed grid or grids of adhesive or by other fixing processes, the heating layer therefore matching the styling grooves perfectly.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be understood better by means of the following description which relates to preferred embodiments given as non-limiting examples and explained with reference to the accompanying schematic drawings, in which:

FIGS. 1 to 5 are perspective views showing the operations of making up a heating layer and fixing it on the internal face of a cover according to a first embodiment of the invention;

FIGS. 6 and 7 are similar perspective views showing the operations of making up a heating layer and fixing it on the internal face of a cover according to a second embodiment of the invention;

FIGS. 8 and 9 are sections showing the application and fixing of a cover equipped with electric heating loom on a foam padding;

FIG. 10 is a magnified section of detail A from Fig. 9, and

FIG. 1 1 is a perspective view and section of a cushion obtained by carrying out the process according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

According to the invention and as shown more particularly by way of example in Fig. 1 to 7 of the accompanying drawings, the process for manufacturing a heating layer and for insertion thereof into a seat cushion between the padding and the cover essentially involves producing, in a first stage, a dimensionally stable heating layer 1 by connection of a coiled heating cable to at least one wide-meshed permeable adhesive grid 5 or 1 1, 13, subsequently fixing said heating layer 1 directly to the internal face of a cover 2, then attaching the cover 2 to a foam padding 3 by adhesion using a fixing adhesive which traverses the wide-meshed grid or grids of adhesive or by other fixing processes, the heating layer 1 therefore matching the styling grooves perfectly. According to a first embodiment shown more particularly in Figs. 1 to 4 of the accompanying drawings, production of the heating layer 1 involves depositing a coiled electric heating cable on a first perforated textile cloth 4 such as gauze, polyester or cotton, subsequently covering the assembly with at least one wide-meshed adhesive grid 5 (Fig. 1 ), this grid in turn being covered by a second perforated textile cloth 6 (Fig. 2) such as gauze, polyester or cotton so as to form a dimensionally stable electric heating cable loom, then assembling the complex by hot calendering (Fig 3) and providing the ends of the electπc heating cable with a connector 7 (Fig 4), the heating layer 1 forming a highly aerated grid which is permeable to the adhesive for fixing the lining The heating layer 1 has a very small thickness so it can match the styling grooves perfectly

The heating layer 1 is advantageously produced continuously by unwinding the textile cloths 4 and 6 as well as the grid or grids 5 from supply rolls (not shown) and by inserting the coiled electric heating cable between said cloths and the grid or grids 5 using a lateral or linear supply robot, the complex being calendered continuously between heating calenders 8, then the individual heating layers 1 are deliv ered by a transverse cut and are each equipped with their connector 7

The heating layer 1 obtained in accordance with this first embodiment is fixed to the internal face of a cover 2 by deposition in the bottom of said cover 2 then by application adhesive 16 passes through the interstices in the textile cloths 4 and 6 and in the gπd or gπds 5 forming the heating layer 1 or through the interstices in the gnds 1 1 and 13 of hot melt adhesive filaments so that said adhesive is in contact with both the foam padding 3 and the cover 2, owing to these interstices

After application of the foam padding 3 covered with the adhesive 16 to the cover 2 carrying the heating layer 1, a supply of heat bπngs about, on the one hand, polymerization of the liquid adhesive 16 and, on the other hand, melting of the grid or grids 5 or gπds 1 1 and 13 of hot melt adhesive filaments, followed by the solidification thereof and the resultant intimate connection of the cover 2 with the heating layer 1 to the foam padding 3

After polymerization, the pressing plate 15 is raised into its rest position and the completed cushion is removed from the mould (Fig 1 1) It may thus be found that the cover 2 adheres perfectly to the foam padding 3 owing to the double adhesion, that is, on the one hand, of the thermosetting adhesive 16 and, on the other hand, of the gπd or gπds 5 or gπds of hot melt adhesive filaments 1 1 and 13 The heating layer 1 is therefore perfectly connected to the foam padding 3 and to the cover and, owing to its shmness, achieved by the process according to the invention, matches all the contours and reliefs of the mould such as the styling groove with a sewing line 17 as shown in Fig 1 1

The lining according to the process of the present invention can obviously be achieved by known adhesion processes, that is, in particular, according to US-A-4 929 304 which proposes polymeπzation of the adhesive by the heat issuing from the heating shaping device containing the cover It is also possible to achieve said polymerization by supplying the heat of a jet of hot air traversing the perforations made in the shaping device containing the cover (JP-A03 068391 ) or by crosslinking a film of adhesive by supplying heat through a steam jet (WO-A 92 08601).

Finally, it is also possible according to FR-A-2 731 380 to deposit a thermosetting liquid adhesive, by transfer, in the cover disposed in a cold shaping device, this adhesive being polymerized by supplying heat originating from the calories stored in the surface of the foam padding previously heated by irradiation. The shaping device 14 can equally consist of synthetic material, layer metal, cast iron or of various composites.

In the example shown in the accompanying drawings, the cover 2 can consist of a textile lined with a sheet of flexible polyurethane foam having a thickness between 2 mm and 5 mm. During the assembly operation, this cover 2 is positioned on the shaping device 14 and held in position by a holding frame 18.

The adhesive 16 can be applied to the surface of the foam padding 3 by spraying using a gun, the quantity of adhesive deposited on the surface of the foam padding 3 advantageously being between 40 grams and 100 grams per square meter.

The hot melt adhesives used to produce the wide-meshed adhesive grid or grids 5 as well as the grids 1 1 and 13 of filaments of hot melt adhesive can advantageously have a crosslinkable base such as polyurethane or a thermoplastic base such as polyamides.

By way of example, the liquid adhesive 16 used will preferably be a polyurethane adhesive containing 100% of dry extracts and two components, that is 70% by weight of polyol having a molecular weight of 6000 and a hydroxyl number of 28 such as that known by the trade name BAYER 3963 of the company BAYER or another polyol of the triol type, and 30% by weight of MDI type isocyante, the mixture being activated with a T.E.D.A. type amine-containing catalyst. In this case, a gun spraying system for two components will advantageously be used.

Other adhesives could obviously be used such as, for example, single component polyurethane adhesives containing 10% of dry extracts or solvent additives, rubber adhesives in the aqueous or solvent phase, thermosetting or thermoplastic type adhesives.

According to a variation of the invention not shown in the accompanying drawings, the cover 2 equipped with the heating layer 1 can be attached to a foam padding 3 by using a film of adhesive between the cover 2 and the padding 3 because when the film of adhesive is liquefied by the supply of heat, it easily passes through the interstices of the grid or grids 5 or of the grids 1 1 and 13 of hot melt adhesive filaments. According to a further variation of the invention not shown in the accompanying drawings, the cover 2 equipped with the heating layer 1 can also be applied to a foam padding

3 by in situ foaming of the foam padding 3 in said cover 2, the foaming mixture poured in-situ easily passing through the interstices of the grid or grids 5 or the grids 11 and 13 of hot melt adhesive filaments.

Finally, the cover 2 equipped with the heating layer 1 can also be attached to a foam padding 3 manually in the conventional manner.

The present invention also relates to heating layers 1 obtained by carrying out the processes described previously, a cover provided with these layers and a seat cushion equipped with said layers.

Owing to the invention, it is possible to produce seat cushions, in particular of polyurethane foam, equipped with heating layers between the cover and the padding, by carrying out a sequence of simple operations which are quick to implement and lead to excellent moldability with accentuated reliefs. Furthermore, the permeability of the padding is improved, the production cost of the seats is reduced and stronger adhesion is obtained because said adhesion is twofold since it uses one or more hot melt grids and a thermosetting adhesive.

It is to be understood that the invention is not limited to the embodiments described and illustrated above, but that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

WE CLAIM

1. A method for manufacturing a heating layer for insertion into a seat cushion between a foam padding and a cover of the seat cushion, at least one of the foam padding and the seat cover having a set of styling grooves, said method comprising: providing a dimensionally stable heating layer having a coiled heating cable and at least one wide-meshed permeable adhesive grid; fixing the heating layer directly to an internal face of the cover; and attaching the cover to the foam padding such that the styling grooves substantially match.

2. The method as defined in claim 1 , wherein providing the heating layer further includes: depositing a coiled electric heating cable having at least one end on a perforated textile cloth thereby forming an assembly; substantially covering the assembly with at least one wide-meshed adhesive grid; covering the at least one wide-meshed adhesive grid with a second perforated textile cloth thereby forming a dimensionally stable electric heating cable loom; forming the assembly to the second perforated cloth by use of heat and pressure; and providing the ends of the electric heating cable with a connector.

The method as defined in claim 2, wherein providing the heating layer further includes: continuously unwinding the textile cloths and the at least one wide meshed adhesive grid from at least one supply roll; inserting the coiled electric heating cable between the textile cloth and the second perforated textile cloth and the at least one grid using a robot; continuously calendering the textile cloth, second perforated textile cloth and the at least one grid, thereby forming the heating layer; and equipping the heating layer with a connector.

4. The method as defined in claim 1 , wherein fixing the heating layer to the internal face of the cover includes adhering the heating layer to the internal face of the cover by applying pressure and heat to the heating layer using a heating plate having one of a nonstick coating and an interposed non-stick sheet between the heating plate and the heating layer.

5. The method as defined in claim 1 , wherein providing the heating layer further includes depositing a coiled electric heating cable on a non-stick paper and extruding a continuous filament of adhesive over portions of the coiled electric cable thereby connecting the coiled electric heating cable to the non-stick paper.

6. The method as defined in claim 1 , wherein fixing the heating layer to the internal face of the cover includes: depositing the heating layer on the internal face of the cover; and extruding a filament of adhesive onto the heating layer thereby adhering the heating layer to the internal face of the cover.

7. The method as defined in claim 1 , wherein attaching the cover to the foam padding includes: arranging the cover on a shaping device; applying the foam padding to a pressure plate; covering the foam padding with a liquid adhesive; lowering the pressing plate thereby bringing the foam padding into contact with the cover; raising the pressing plate to a rest position; and removing the completed seat cushion from the mould.

8. The method as defined in claim 7, wherein covering the foam padding with a liquid adhesive includes applying the liquid adhesive to the surface of the foam padding by spraying using a gun, thereby depositing a quantity of adhesive on the surface of the foam padding being between 40 grams and 100 grams per square meter.

9. The method as defined in claim 2, wherein the adhesives used to produce the at least one wide-meshed adhesive grid have a crosslinkable base such as polyurethane or a thermoplastic base such as polyamides.

10. The method as defined in claim 2 wherein the textile cloth and second perforated textile cloth is selected from a group consisting of gauze, polyester and cotton.

1 1. The method as defined in claim 7, wherein in the liquid adhesive is a polyurethane adhesive containing 100% of dry extracts and two components, that is 70% by weight of polyol having a molecular weight of 6000 and a hydroxyl number of 28 such as that known by the trade name BAYER 3963 belonging to the company BAYER or another polyol of the triol type, and 30% by weight of MDI type isocyante, the mixture being activated with a T.E.D.A. type amine-containing catalyst.

12. The method as defined in claim 1 , wherein attaching the cover to the foam padding includes applying a film of adhesive between the cover and the foam padding.

13. The method as defined in claim 1 , wherein attaching the cover to the foam padding includes pouring the foam padding from a foaming mixture in-situ.

14. The method as defined in claim 1 , wherein attaching the to the foam padding includes manually attaching the cover and heating layer to the foam padding.

15. A seat comprising: a cushion; a cover positioned substantially about the cushion; and a heating layer disposed substantially between the cushion and the cover, the heating layer having a coiled heating cable having at least one connector end and at least one wide-meshed permeable adhesive grid, wherein at least one of the cover and the cushion has a set of styling grooves, and the heating layer substantially matches the styling grooves. 16 The seat as defined in claim 15, wherein the heating layer includes a second perforated textile cloth that forms a dimensionally stable electric heating cable loom with the ends of the electπc heating cable loom having at least one connector

17 The seat as defined m claim 15 wherein the heating layer includes a non-stick paper and a filament of adhesiv e ov er portions of the coiled heating cable

18 The seat as defined in claim 15 wherein the heating layer is fixed to the internal face of the cover