WO2003031223A1

WO2003031223A1 - Elastomeric seat suspension system

Info

Publication number: WO2003031223A1
Application number: PCT/CA2002/001510
Authority: WO
Inventors: Mark Weierstall
Original assignee: Woodbridge Foam Corporation
Priority date: 2001-10-05
Filing date: 2002-10-04
Publication date: 2003-04-17

Abstract

A seat suspension system comprising a first frame member, a second frame member and an elastomeric composite sheet secured to the first frame member and the second frame member. The elastomeric composite sheet comprises an elastomer layer and a non-elastomer reinforcing layer arranged coterminously to define a reinforcement area.

Description

ELASTOMERIC SEAT SUSPENSION SYSTEM

TECHNICAL FIELD

In one of its aspects, the present invention relates to an elastomeric seat suspension system. In another of its aspects, the present invention relates to a process for producing an elastomeric composite sheet. In yet another of its aspects, the present invention relates to a vehicular seat comprising an elastomeric seat suspension system.

BACKGROUND ART

Passenger seats in vehicles, such as automobiles, are conventionally fabricated from a foam (usually a polyurethane foam) 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.

It is also known in the art that, while the resiliency of the foamed material in the seat provides passenger comfort, it does not typically provide the necessary structural strength for the seat. This necessitates additional reinforcement of the seat to provide the degree of structural strength to ensure proper mounting of the seat within the vehicle and, optionally, proper support for anti-submarine features and the like.

Thus, it is known in the art to dispose a foam seat in a "pan" which consists of a frame with respect to which the foam material and trim cover are secured. The frame itself is then mounted to the vehicle. Conventional such pans comprise a perimeter frame which includes support rails that stiffen the frame and provide a suitable attachment point for means used to anchor the seat to the vehicle.

Over the years, various advances have been made in the art to improve the pan which receives the combined foam element/trim cover. For example, it is known in the art to employ a so-called Flex-o- Lator™ suspension system which consists of a perimeter frame that supports the B-surface (this is the underside opposite the principal seating surface) of the foam element via a series of wires which are connected to the frame by a series of springs. This suspension system has found significant popularity in the North American automobile market. The springs used in the suspension system can be altered to alter the deflection properties of the suspension system. While this system has the advantage of being relatively low cost, it is difficult to install and requires a relatively thick foam element to provide adequate support for the occupant in the seat. Further, the Flex-o-Lator™ suspension system is susceptible to so-called BSR (buzz/squeak/rattle) problems.

A similar seat suspension in the art is known as a Sinuous Spring suspension system. This system is similar to the Flex-o-Lator™ system except, instead of straight wires supporting the foam element/trim cover combination, sine or square wave shaped steel springs are attached to support this combination. This system has been popular in the Japanese market. Deflection of this system is varied by controlling one or more of spring gauge, frequency of the wave, shape, amplitude of the wave shape and configuration of the wave shape. While the system is durable, it is relatively expensive to manufacture and use.

The prior art has also turned to non-metal support systems in seat pans for vehicular applications. Thus, it is known to utilize a Dymetrol™ material in place of the wires and sine waves of the systems described above. The Dymetrol™ material consists of a woven fabric having an elastomeric filament disposed therein. The advantages of this system are that it is lightweight, provides higher damping properties, is durable and has potential for supporting thin seating. Unfortunately, it is very expensive, confers a harsh feeling to the occupant thereby comprising seat comfort and is unidirectional. By "unidirectional" it is meant that the material stretches in one direction only thereby limiting occupant comfort.

A similar system to the Dymetrol™ material is referred to in the art as the Pirelli Mat. This material is popular in Europe and has the potential for improving support for thin seating. Further, the material is recyclable. Unfortunately, it is also susceptible to dry rot. Further, it is one of the heavier suspension systems in commercial use thereby adversely affecting fuel economy of the vehicle in which it is installed - this is particularly disadvantageous at a time when the automotive industry is trying to reduce the weight of vehicles by reducing the weight of components therein. Further, this system in unidirectional in that it suffers from the same disadvantages as the Dymetrol™ material described in the proceeding paragraph. See also the teachings of British patent 1,500,725 for a discussion of the Pirelli Mat.

Other prior art references of possible interest include one or more of the following:

United States Patent 4,059,660 (Roth et al.);

United States Patent 4,116,736 (Sanson et al.);

United States Patent 4,598,949 (Miln);

United States Patent 4,842,257 (Abu-Isa et al.);

United States Patent 4,869,554 (Abu-Isa et al.);

United States Patent 5,116,557 (Debaes et al.);

United States Patent 5,294,386 (Roth et al.);

United States Patent 5,468,048 (Clemens et al.);

Unites States Patent 5,585,161 (Difloe et al.); and

United States Patent 5,775,779 (Abu-Isa et al.). In light of the above-mentioned deficiencies of the prior art, there is an ongoing need for a seat suspension system, particularly one for use in a vehicle, which combines the advantages of known seat suspension systems while obviating or mitigating the disadvantages of these known systems. More particularly, it would be advantageous to have a vehicular seat suspension system which combines at least two or more, preferably substantially all, of the following: (i) it is cost effective, (ii) it provides adequate support for thin foam seating, (iii) it has improved damping properties, (iv) it obviates or mitigates the need for reinforcement/protection on the B-surface of the foam element, (v) it has lower BSR, (vi) it is recyclable, and (vii) it is responsive to a load in a multi-directional manner.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to obviate or mitigate at least one of the above-mentioned disadvantages of the prior art.

Accordingly, in one of its aspects, the present invention provides a seat suspension system comprising a first frame member, a second frame member and an elastomeric composite sheet secured to the first frame member and the second frame member, the elastomeric composite sheet comprising an elastomer layer and a non-elastomer reinforcing layer arranged coterminously to define a reinforcement area.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described with reference to the accompanying drawings, in which:

Figure 1 illustrates a top-plan view of components of a preferred embodiment of the present seat suspension system;

Figure 2 illustrates an enlarged view of a portion of Figure 1; Figure 3 illustrates a top-plan view of a preferred embodiment of the support system used in the present seat suspension;

Figure 4 illustrates an enlarged view of Figure 3;

Figure 5 illustrates a schematic of a production process for component of the preferred embodiment of the present seat suspension system; and

Figures 6-9 illustrate various views of a vehicular seat incorporating a prefeπed embodiment of the present seat suspension system.

BESTMODE FOR CARRYINGOUTTHEINVENTION

Accordingly, an aspect of the present invention relates to a seat suspension system, particularly one for use in a vehicular of passenger seat. As used throughout this specification, the term "seat" is intended to have its conventional meaning and includes one or both of cushion (i.e., the portion of the seat on which the occupant sits) and a back or backrest (i.e., the portion of the seat which supports the back of the occupant). As is known in the automotive, airline and related industries, a "seat" unquote a cushion, a back (or backrest) or a unit construction comprising a cushion and back (or backrest).

Thus, the present inventor has developed a novel seat suspension system which obviates or mitigates at least one of the above-mentioned disadvantages of the prior art.

In its preferred embodiment, the present seat suspension system combines one or more of the following advantages:

• deflection properties of the suspension system may be readily varied by varying the particular form of reinforcement layer and the chemistry used in the elastomer layer; • the present seat suspension system is cost competitive with or substantially lower in cost than conventional seat suspension systems;

• the present seat suspension system provides full surface support allowing for the use of relatively thin foam elements in the seat product;

• the present seat suspension system allows for ready incorporation of occupant sensor technology;

• the present seat suspension system provides for improved and broader range in damping properties (e.g., hysteresis);

• the present seat suspension system obviates or mitigates the need for reinforcement or protective layers to avoid damage to the B-surface of the foam element in the seat;

• the present seat suspension system has lower BSR compared to various of the conventional seat suspension systems;

• the present seat suspension system allows for attachment of the trim cover to the suspension system unlike conventional suspension systems;

• the present seat suspension system is recyclable; and

• the present seat suspension system allows for ready variation of the reinforcement properties (both locally and overall) of the suspension system at different locations thereof - e.g., through the use of different reinforcing layers and/or the use of different elastomers and/or the use of varying elastomer thickness. A particular important advantage of the present seat suspension system is that it is "multi-directional" in is reinforcement properties. By this is it meant that the present seat suspension system, unlike various of the known suspension systems described hereinabove, flexes in at least two directions when a load is placed thereon. In a preferred embodiment this may be achieved by orienting elements in the reinforcing layer in a manner such that they are in a non-parallel relationship to the frame elements (or the connectors) to which the elastomeric layer/reinforcing layer combination (also referred to herein as the elastomeric composite sheet) are secured.

As set out above, the present seat suspension system comprises a first frame member, a second frame member and an elastomeric composite sheet secured to the first frame member and the second frame member. The elastomeric composite sheet comprises an elastomer layer and a non-elastomer reinforcing layer.

Preferably, the first frame member and the second frame member are substantially opposed to one another. More preferably, the first frame member and the second frame member are comprised in a so-called perimeter frame or seat pan which received the elastomeric composite sheet. As described above, an advantage of the present seat suspension system is that it provided reinforcement in a multi-directional manner. Accordingly, it is possible to utilize the perimeter frame having means to secure the elastomeric composite sheet along substantially the entire perimeter of the sheet.

The elastomeric composite sheet comprises an elastomer layer and a non-reinforcing layer. Generally, these layers are coterminus by being overlapped or otherwise disposed in relation to one another such that both are present in the area where occupant load is applied to the seat suspension system. Preferably, the reinforcing of the elastomeric composite sheet (i.e., the area of the sheet where occupant load is applied) comprises the reinforcing layer being embedded in the elastomer layer. In another embodiment, a pair of elsatomer layers may be provided and have interposed therebetween the non-elastomer reinforcing layer.

Preferably, the elastomer layer comprises an isocyanate-based elastomer such as a polyurethane elastomer. Non-limiting examples of polyurethane elastomer systems are commercially available and generally comprises a polyol or resin component and an isocyanate component. One non-limiting example of a useful polyurethane elastomer system is commercially available from Bayer Corporation under the trade names Polyol NB#1308698-B and Isocyanate Mondur™ PF. Another non-limiting example of a useful polyurethane elastomer system is commercially available from BASF Corporation under the trade names Polyol NB#19747-3-77 and Isocyanate Elastoskin™ S51140T. Of course, those of ordinarily skill in the art will understand that other elastomers may be used in place of isocyanate- based elastomers. For example, it is possible to utilize elastomers such as butadiene rubber, nitrite rubber, natural rubber, styrene-butadiene rubber, ethylene/propylene rubber, butyl rubber, synthetic polyisoprene, neoprene rubber, polysulfide rubber and the like may be used in the elastomer layer of the present seat suspension system.

The reinforcing layer is relatively non-elastomeric - i.e., relative to the elastomeric layer. In highly preferred embodiment, the reinforcing layer comprises a poor sheet. The reinforcing layer may be woven or non-woven. Preferred embodiments of the reinforcing layer for use herein may be selected form the group comprising polyester, fiberglass, burlap, cotton, hemp, nylon, polyethylene, polypropylene and combinations thereof. A preferred polyester porous sheet for use as a reinforcing layer in the present seat suspension system is commercially available from Phifer under the trade name ARLYN™. This is generally a polyester mesh having a diamond shape porous pattern. The orientation of this pattern will be discussed in more detail herein below.

In a prefeπed embodiment of the present seat suspension system, one or more connectors are provided to secure the elastomeric composite sheet to the frame member. The specific design and location of such connectors will be within the purview of a person skilled in the art.

Preferably, the elastomeric composite sheet is generally square- shaped or rectangular-shaped, and has a connector attached at least at opposed sides of the sheet. Alternatively, it is possible to utilize other shapes for the elastomeric composite sheet such as other polygons (e.g., hexagonal, octagonal, etc.), round (e.g., circular, oval, etc.) and other curvilinear shapes. In one embodiment, the connector may be an elongate member such as a metal wire which is embedded in the elastomeric sheet or attached to the elastomeric sheet via a pocket of other suitable means. In another embodiment, the connector may be a so-called J-connector or other mechanical connectors conventionally used in the automotive industry to attach trim covers to frame elements.

In a particularly preferred embodiment in the present seat suspension system, the non-elastomeric reinforcing layer comprises a porous design which is defined by interconnected elongate members of the porous sheet. Preferably, these elongate members of the porous sheet are in a non- parallel relationship with the connectors used to secure the elastomeric composite sheet to the frame elements of the seat suspension system (or to the frame elements themselves if, for example simple hooks are used to secure the composite to the frame elements). This provides for multi-directional reinforcement of a load placed on the seat suspension system. Generally, this feature of the present seat suspension can also be obtained by orienting the porous reinforcing layer such that the members making up the pores are in a general non-parallel relationship with the connectors to affix the elastomeric composite sheet to the frame elements. This is a distinct advantage of the present seat suspension system.

With reference to Figures 1 and 2, there is illustrated a reinforcing layer suitable for use in the present seat suspension system. Reinforcing layer 10 comprises a porous sheet 15. Porous sheet 15 has a repeating pattern of pores which are generally diamond shaped. In the illustrate embodiment, sheet 15 the polyester mesh commercially available from Phifer under the trade name ARLYN™. At the ends of sheet 15 are disposed a pair of metal wires 20. As shown, the marginal edges of sheet 15 are wrapped around wires 20.

Figures 3 and 4 coπespond generally to Figures 1 and 2 respectively. In Figures 3 and 4, reinforcing layer 10 illustrated in Figures 1 and 2 has been embedded in a polyurethane elastomer using a two-part aluminum mold thereby encapsulating reinforcing layer 15 in elastomeric layer 25 to provide an elastomeric composite sheet 30.

In the illustrated embodiment, the elastomeric layer 25 is applied over the entirety of porous sheet 15 and metal wires 20. Of course, it is possible to modify the illustrated embodiment so that the portion of reinforcing layer 10 near metal wires 20 (or any other area of porous sheet 15) is not covered with elastomeric layer 25.

With continued reference to Figures 3 and 4, the marginal areas of elastomeric composite sheet 30 are provided with a series of apertures 35.

Apertures 35 preferably are created after production of elastomeric composite sheet 30. As will be described below, apertures 35 are used to facilitate securing elastomeric composite sheet 30 in the frame of a vehicular seat.

With reference to Figure 5, there is shown a schematic of a production process for producing elastomeric composite sheet 30. Thus, shown a system 100 for producing elastomeric composite sheet 30. System 100 comprises a rule 105 having wound thereon sheet material useful as the non-elastomeric reinforcing layer in the present suspension system. Downstream from roll 105 are a pair of rolls 100,115 which dispense in a generally parallel relationship, a continuous supply of wires 112,117 to overlie the margin of sheet material being dispensed from roll 105. Next, a pourhead 120 is provided and is capable of traversing from side to side over sheet material being dispensed from roll 105. Pourhead 120 dispenses chemicals 125 used to produce the elastomeric layer of the seat suspension system - this system is particularly well suited for urethane elastomer forming chemicals. Downstream of pourhead 120 are a pair of folding stations 130,135 which serve to fold over the marginal edges of the sheet material being dispensed from rool 105 so as to encapsulate metal wires 112,117. Next, the folded sheet emanating from stations 130,135 is passed between a pair of heated rollers 140,145 which serve to control the thickness of the elastomeric layer being produced while facilitating curing of the chemicals to form the elastomeric layer. The partially or fulled cured sheet emanating from rollers 140,145 is then passed to a die cutting station 150 which serves to cut the sheet into separate elastomeric composite sheets 155 for use in the present seat suspension system. This production process is useful, for example, to produce elastomeric composite sheet 30 described hereinabove.

Of course, other production methods will be apparent to those of skill in the art. For example, it is possible to produce the elastomeric composite sheet without the connectors embedded therein and attach these connectors as a post-production step by stitching methods and other mechanical affixation means.

With references to Figures 6-9, there is illustrated a vehicular seat system 200 (without the foam or other resilient body) incorporating two embodiments of the present elastomeric seat suspension system.

As illustrated vehicular seat system 200 comprises a seat bottom portion 210 and a seat back portion 250.

Seat bottom portion 210 comprises a pair of end frame members

215,220 which are interconnected by a pair of similar side frame members 225. Attached to end frame members 215,220 is elastomeric composite sheet 30. Specifically, one edge of elastomeric composite sheet 30 is attached to end frame member 220 via series of metal clips 230 which encompass metal wires 20 embedded in elastomeric composite sheet 30 - see particularly Figure 8. Further, the other edge of elastomeric composite sheet 30 is attached to end frame member 215 via series of metal hooks 235 which at least partially encircle both metal wires 20 embedded in elastomeric composite sheet 30 and end frame member 215 - see particularly Figure 9.

Seat back portion 250 comprises a U-shaped frame member 255 which is pivotally connected to seat bottom portion 210. Extending between the two parallel members of U-shaped frame member 255 are a pair cross- members 260.

Attached to cross-members 260 of U-shaped frame member 255 is elastomeric composite sheet 30a. Elastomeric composite sheet 30a similar to elastomeric composite sheet 30 described above with the exception that the combination metal wires 20 and apertures 35 in the marginal regions in the latter have been replaced with a sewn-in J-retainer 22. Each J-retainer 22 of elastomeric composite sheet 30a is then hooked over each cross-member 260 of U-shape frame member 255 to produce seat back portion 250.

Preferably elastomeric composite sheet 30 and/or 30a are pre- tensioned when mount in seat back portion 250 and/or seat bottom portion 210, respectively. The amount of pre-tensioning is not particularly restricted provided that, on the one hand, it is enough to ensure there is no slack in the elastomeric composite sheet while, on the other hand, it is not excessive so as to defeat or obviate the elastomeric properties of the elastomeric composite sheet. Practically, it has been found useful to stretch the elastomeric composition to in an amount of from about about V% inch to about inch beyond it's resting state.

A resilient body (e.g., polyurethane foam, fibrous matrix, etc.), together with a suitable trim cover may then be disposed over each of seat bottom portion 210 and seat back portion 250 to complete construction of vehicular seat system 200. Alternatively, elastomeric composite sheet 30 may be incorporated (e.g., molded) into the resilient body and then connected to the free elements of seat bottom portion 210 and/or seat back portion 250.

While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments.

All publications, patents and patent applications refeπed to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

Claims

What is claimed is:

1. A seat suspension system comprising a first frame member, a second frame member and an elastomeric composite sheet secured to the first frame member and the second frame member, the elastomeric composite sheet comprising an elastomer layer and a non-elastomer reinforcing layer aπanged coterminously to define a reinforcement area.

2. The system defined in claim 1, wherein the reinforcing layer is embedded in the elastomer layer.

3. The system defined in claim 1, wherein the reinforcing layer comprises a pair of elastomer layers and the non-elastomer reinforcing layer is interposed between the elastomer layers.

4. The system defined in claim 1, wherein the first frame member and the second frame member are substantially opposed to one another.

5. The system defined in claim 1, wherein the first frame member and the second frame member are connected the at least one further frame member to form a perimeter frame which substantially encompasses the elastomeric composite sheet.

6. The system defined in claim 1, wherein the elastomer layer comprises an isocyanate-based elastomer.

7. The system defined in claim 1, wherein the elastomer layer comprises a polyurethane elastomer.

8. The system defined in claim 1, wherein the reinforcing layer is woven.

9. The system defined in claim 1, wherein the reinforcing layer is non- woven.

10. The system defined in claim 1, wherein the reinforcing layer comprises porous sheet.

11. The system defined in claim 10, wherein the porous sheet comprises a series of elongate members which are interconnected to define a repeating pattern of pores.

12. The system defined in claim 11, wherein the repeating pattern has a substantially uniform shape and a substantially uniform size.

13. The system defined in claim 11, wherein the repeating pattern has a substantially uniform shape and a non-uniform size.

14. The system defined in claim 11, wherein the repeating pattern has a non-uniform shape and a substantially uniform size.

15. The system defined in claim 10, wherein the porous sheet is selected from the group comprising polyester, fibreglass, nylon, polyethylene, polypropylene and combinations thereof.

16. The system defined in claim 1, further comprising a first connector to secure the elastomeric composite sheet to the first frame member.

17. The system defined in claim 1, further comprising a second connector to secure the elastomeric composite sheet to the second frame member.

18. The system defined in claim 1, further comprising a first connector to secure the elastomeric composite sheet to the first frame member and a second connector to secure the elastomeric composite sheet to the second frame member.

19. The system defined in claim 18, wherein first connector comprises a first elongate bar.

20. The system defined in claim 19, wherein the first elongate bar is disposed in a non-parallel relationship with respect to the elongate members of the porous sheet.

21. The system defined in claim 18, wherein the first connecter is substantially encompassed by at least one of the elastomer layer and the reinforcing layer.

22. The system defined in claim 18, wherein the first connecter is substantially encompassed by both of the elastomer layer and the reinforcing layer.

23. The system defined in claim 18, wherein the second connector comprises a second elongate bar.

24. The system defined in claim 18, wherein the second elongate bar is disposed in a non-parallel relationship with respect to the elongate members of the porous sheet.

25. The system defined in claim 18, wherein the second connector is substantially encompassed by at least one of the elastomer layer and the reinforcing layer.

26. The system defined in claim 18, wherein the second connector is substantially encompassed by both of the elastomer layer and the reinforcing layer.

27. The system defined in claim 1, wherein the elastomeric composite sheet has a thickness in the range of from about 0.5 mm to about 3.0 mm.

28. The system defined in claim 1, wherein the elastomeric composite sheet has a thickness in the range of from about 0.5 mm to about 2.0 mm.

29. The system defined in claim 1, wherein the elastomeric composite sheet has a thickness in the range of from about 1.0 mm to about 1.5 mm.