GB2355400A

GB2355400A - Vehicle seat cushion

Info

Publication number: GB2355400A
Application number: GB0025772A
Authority: GB
Inventors: Masatsugu Saito
Original assignee: Ikeda Bussan Co Ltd
Current assignee: Ikeda Corp
Priority date: 1999-10-22
Filing date: 2000-10-20
Publication date: 2001-04-25
Anticipated expiration: 2020-10-20
Also published as: GB0025772D0; JP2001112586A; GB2355400B

Abstract

An automobile seat comprises cushion 21 mounted on seat frame 22. The part 23 of cushion 21 which supports an occupants hip and legs comprises recess 27 which faces the inner surface of frame 22 and contains pad 29. Pad 29 has grooves 31 on its lateral sides which receive inwardly projecting parts of cushion 21 and has a higher modulus of elasticity than cushion 21. Pad 29 is preferably integrally moulded to cushion 21 and is made of a flexible material with a Youngs modulus 20-30% greater than cushion 21. Grooves 31 are preferably 220-280 mm apart. Cushion part 23 is preferably 20-30 mm thick and may have raised sides 25. Both cushion 21 and pad 29 may be polyurethane. Recess 27 is preferably rectangular.

Description

2355400 CT (S r 'S 7- -a -J is AUTOMOTIVE SEAT The present invention

relates to seats, and more particularly to automotive seats of a type that comprises a seat frame and a cushion body held by the seat frame. More specifically, the present invention is concerned with automotive seats of a type whose cushion body is improved in construction to lo provide a seat occupant with.. comfortable sitting.

Hitherto, various types of seats have been proposed and put into practical use, particularly in the field of motor vehicles. For providing seat occupants with comfort sitting, some of them have made an improvement in the construction of the cushion body, which is, for example, usage of a softer cushion, usage of a somewhat harder cushion, usage of a cushion made of foamed polyurethane or the like,, etc. ..

However, hitherto, in considering the construction of the cushion body, the cause of fatigue inevitably applied to the hip and femur portions of a seat occupant when he or she is sitting on the seat for long time has been given only a little thought.

It is therefore an object of the present invention to provide an automotive seat which is constructed by putting the cause of fatigue due to long sitting'into consideration.

According to a first aspect of the present invention,, there is provided an automotive seat which comprises a seat frame; a cushion body mounted on the seat frame., the cushion body including a main portion by which hip and femur portions of a seat occupant are to be substantially supported; a recess formed in the main portion of the cushion body, the recess facing to an inner surface of the seat frame; and a pad member intimately received 2 in the recess, the pad member having at lateral sides thereof respective grooves each extending in a fore-and-aft direction with respect to the cushion body, each groove intimately receiving therein an inwardly projected part of said cushion body, wherein the pad member has a higher value in modulus of elasticity than that of the main portion of the cushion body, and the grooves of the pad member are positioned to be placed below greater trochanters of the hip portion of the seat occupant.

According to a second aspect of the present invention, there lo is provided an automotive seat which comprises a seat frame; a cushion body made of a foamed polyurethane and mounted on the cushion body including a main portion by which hip and femur port'lons of a heat occupant are to be substantially supported and a pair of raised side portions which are integrally formed on lateral sides of the main portion; a generally rectangular recess formed in the main portion of the cushion body,, the recess facing to an inner surface of the seat frame; and a generally rectangular pad member made of a foamed polyurethane and intimately received In the rectangular recess, the pad member having at lateral sides thereof respective grooves each extending in a fore-and-aft direction with respect to the cushion body, each groove intimately receiving therein an inwardly projected part of said cushion body, wherein the pad member has a higher value in modulus of elasticity than that of the main portion of the cushion body, and the grooves are spaced from each other by approximately 220mm to 280mm.

Other objects and advantages of the present Invention will become apparent from the following description when taken in conjunction with the accompanying drawings, in which:

Fig. I is a plan view of a cushion body used In an automotive seat according to the present invention; Fig. 2 is a front left sectiona I view of the automotive seat; Fig. 3 is a schematic view of a human body, showing a tuber ischiadicum and its associated bones present'in the human body; and Fig. 4 is a front right view of a cushion body of an automotive seat with the hip portion of the human body being put on the cushion body.

Before describing the detail of the present invention, consideration will be commenced, with.reference to Figs. 3 and 4, lo on the cause of the fatigue that is inevitably applied to a seat occupant when he or she is sitting on the seat for a long time.

In Fig. 3,, there is schematically shown a human body H (viz... seat occupant) taking a posture to sit on an automotive seat. Two tuber ischladicta, 13 (only one is shown) are arranged In a hip portion 11 of the human body H. A backbone 10 extends upward from a mated portion of the tuber ischiadicia, 13 and a pair of femurs 15 (only one is shown) extend forward from the tuber ischiadicums 13 through respective greater trochanters 17.

In Fig. 4,, there is schematically shown a front right sectional view of a cushion body CB of the seat in a condition wherein the hip portion 11 of the seat occupant H is put on the cushion body CB. The cushion body CB comprises a major center portion 5 and opposed side portions 7.

As will be understood from these drawings, when the seat occupant H sits on the seat,, the musculus gluteus positioned below the tuber ischladic;a 13, the femurs 15 and the greater trochanters 17 is compressed by a certain degree. Thus, if the seat occupant H keeps his or her sitting posture for a long time, a so-called blood flow obstruction tends to occur in the musculus gluteus which causes the fatigue of hip portion 11 and that of the femur portions.

In view of the above, the automotive seat of the present Invention has an improved cushion body which is constructed to 4 minimize the pressure applied to the musculus gluteus of the seat occupant.

Referring to Figs. 1 and 2.. there is shown a cushion body 21 used in an automotive seat of the present invention.

As is seen from Fig. 2, the cushion body 21 Is mounted on a seat frame 22. Although not shown in the drawings,, the cushion body 21 is covered with a decorative outer skin member. The seat frame 22 may be of a pan type or a type having cushion springs.

As is seen from Fig. 1, the cushion body 21 is constructed of a flexible material, such as a foamed polyurethane or the like and comprises generally a main portion 23 which is sized and positioned to support thereon the hip portion 11 and femur portions of the seat occupant H and a pair of side portions 25 which are integrally formed at both sides of the main portion 23, It is to be noted that the seat occupant H mentioned herein is a person having an averaged conformation.

As is seen from Fig. 2, in the illustrated embodiment., each side portion 25 is raised a little from the side of-the main portion 23 together with the seat frame 22.

As is seen from Figs. 1 and 2, the cushion body 2 1 is formed at the main portion 23 thereof with a gpnerally rectangular recess 27 which faces downward. That is, the recess 27 faces an inner surface of the seat frame 22.

Within the recess 27, there is intimately installed a rectangular pad member 29 which Is constructed of a flexible material, such as a foamed polyurethane or the like. Thus, as is seen from Fig. 20 at the main portion 23, the pad member 29 is disposed between the cushion body 21 and the seat frame 22.

If desired, the pad member 29 may be used as an insert when the cushion body 21 is molded. That is, Integral molding may be used for producing a unit including the cushion body 21 and the pad member 29.

It is now to be noted that the flexible material for the pad member 29 has a higher value in modulus of elasticity than that for the main portion 23 of the cushion body 21. That Is, In the illustrated embodiment, the modulus of elasticity of the flexible material for the pad member 29 is about 65%, while the modulus of elasticity of the flexible material for the cushion body 21 Is about 40%. It is only necessary that the material for the pad member 29 has the modulus of elasticity higher than that for the cushion body 21 by 20% to 30%.

In the illustrated embodiment, when the flexible materials lo for the pad member 29 and cushion body 21 were subjected to a hardness test wherein each test piece was compressed by 25%,, the material for the pad member 29 showed a hardness higher than that for the cushion body 21 by over SKgf/314cM2. In fact, the hardness of the material for the pad member 29 was M2.

30Kgf/314 while the hardness of the material for the cushion body 21 was about 20Kgf/314m2. According to a performance test, it was found that 2SKgf/314M2 to 3SKgf/314M2 were allowed by the material for the pad member 29 when the material for the cushion body 21 showed 20KGf/314m,'.

As is seen from the drawings., the rectangular pad member 29 is formed at. its both sides with respective grooves 31 each extending in a fore-and-aft direction. with respect to the cushion body 21,, as is understood from Fig. 1. Each groove 31 intimately receives an inwardly projected part of the cushion body 21.

It is to be noted that the grooves 31 are spaced from each other to be respectively positioned below the corresponding greater trochanters 17 of the seat occupant H. In persons having an averaged conformation, the distance between the two greater trochanters 17 is substantially the same.

Due to provision of the grooves 31, the load tr-ansmission, that would occur between the cushion body 21 and the pad member 29 upon sitting of the seat occupant H on the seat, is suppressed or at least minimized at the portions where the 6 grooves 31 are provided. With this, the portion of the cushion body 21 that would be largely depressed upon sitting of the seat occupant H on the seat can be shifted to another portion.

As is seen from Fig. 1, in the illustrated embodiment, the distance Ll between the two grooves 31 is about 220mm to 280mm, preferably about 250mm which correspond s the distance between the two greater trochanters of the person having the averaged conformation. If the distance Ll is smal than 220mm, the supporting performance of the cushion body 21 becomes poor, io and if the distance Ll is greater than 280mm, the pressure applied to the lower portion of the greater trochanters 17 becomes remarkable.

Furthermore, as is seen from Fig. I., the length (1-2 + 1-3) of each groove 31 is about 90mm to 210mm, preferably 150mm.

More specifically., the length L2 between the front end of the groove 31 and an imaginary line HPL that extends laterally through a hip point HP of the cushion body 21 is about 60mm to 12Omm, preferably 90mm, and the distance Q between the Imaginary line HPL and the rear end of the groove 31 is about 30mm to 90mm, preferably 60mm. When the length L2 is smaller than 60mm, uncomfortable slippage of the seat occupant's hip portion 11 tends to take place, and when the length L2 is greater than t20mm, supporting performance to the seat occupant's femur portions becomes poor. Furthermore, when the length L3 is smaller than 30mm, the pressure applied to the musculus gluteUs maximus of the seat occupant H becomes remarkable, and when the length L3 is greater than 90mm, the cushion body 21 tends to have creases lowering the aesthetic value thereof.

As is seen from Fig. 2, the thickness L4 of the main portion 23 of the cushion body 21 is about 20mm to 30mm.

The entire contents of Japanese Patent Application 11 300634 (filed October 22, 1999) are incorporated herein by reference.

7 Although the Invention has been described above with reference to the embodiment of the invention,, the invention is not limited to such embodiment as described above. Various modifications and variations of such embodiment may be carried 5 out by those skilled in the art, in light of the above descriptions.

8

Claims

CLAIMS 1. An automotive seat comprising: a seat frame; a cushion body

mounted on said seat frame, said cushion body including a main portion by which hip and femur portions of a seat occupant are to be substantially supported; a recess formed in said main portion of the cushion body, said recess facing to an inner surface of said seat frame; and a pad member Intimately received in said recess, said pad member having at lateral sides thereof respective grooves each extending in a fore-and-aft direction with respect to said cushion body, each groove intimately receiving therein an inwardly projected part of the cushion body, wherein said pad member has a higher value in modulus of elasticity than that of the main portion of said cushion body.. and said grooves of said pad member are positioned to be placed below greater trochanters of the hip portion of the seat occupant.
2. An automotive seat as claimed in Claim 1, in which a flexible material of said pad member has the modulus of elasticity that is higher than that of a flexible material of the main portion of said cushion body by approximately 20% to 30%.
3. An automotive seat as claimed in Claim 2,, in which the flexible material of said pad member shows a hardness higher than the flexible material of said main portion by over 5kgf/314cm2, when subjected to a hardness test wherein each test piece is compressed by 25%.
4. An automotive seat as claimed in Claim 3, in which the Iardness of the flexible material of said pad member Is approximately 2SKgf/314CM2 to 35Kgf/314cm' and the hardness of the flexible material of said main portion is approximately 9 20Kgf/314cm2.
S. An automotive seat as claimed in Claim 4,, in which the hardness of the flexible material of said pad member Is approximately 30Kgf/314CM2.
6. An automotive seat as claimed in Claim 2, in which the distance between the two grooves is approximately 220mm to 280mm.
7. An automotive seat as claimed in Claim 6, in which the distance between the two grooves is approximately 250mm.
8. An automotive seat as claimed in Claim 6,, in which the thickness of the main portion of said cushion body is approximately 20mm to 30mm.
9. An automotive seat as claimed in Claim 1.. in which each of said cushion body and said pad member is made of foamed polyurethane.
10. An automotive seat comprising: a seat frame; a cushion body made of foamed polyurethane and mounted on said cushion body including a main portion by which hip and femur portions of a sjeat occupant are to be substantially supported and a pair of raised side portions -which are Integrally formed on lateral sides of said main portion; a generally rectangular recess formed in said main portion of the cushion body, said recess facing to an inner surface of said seat frame; and a generally rectangular pad member made of foamed polyurethane and intimately received in said rectangular recess, said pad member having at lateral sides thereof respective grooves each extending in a fore-and-aft direction with respect to said cushion body,, each groove intimately receiving therein an inwardly projected part of said cushion body, wherein said pad member has a higher value In modulus of elasticity than that of the main portion of said cushion body, and said grooves are spaced from each other by approximately 220mm to 280mm.
11. An automotive seat substantially as described with reference to, and as shown in, Figures 1 and 2 of the accompanying drawings.