GB2460472A

GB2460472A - Seat with a pivoting backrest

Info

Publication number: GB2460472A
Application number: GB0809952A
Authority: GB
Inventors: James Shing Hin Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-05-30
Filing date: 2008-05-30
Publication date: 2009-12-02
Also published as: GB0809952D0; CN101590911A; US20090295209A1

Abstract

A seat comprising a backrest 22 pivoted on the frame about a high level transverse axis 23 with respect to the seat pan or cushion 21 and a method of retaining the backrest at a desired angular position (not shown in figures), such a backrest permits a range of supported semi-reclining seating positions without inconveniencing an occupant of the next rearward seat row, the seat also permits selection of a seat pan length to suit the height of the occupant.

Description

SEAT WITH PIVOTING BACKREST

This invention relates to a pivoting backrest of a seat, and is particularly, though not exclusively, intended for use in passenger vehicles such as aircraft.

Prolonged sitting without substantial change of position is bad practice, and may result in stiffness and pain. Especially in the case of aircraft, such prolonged sitting has been identified as a cause of blood clots in the lower leg, which can in turn have serious medical consequences. Passengers are encouraged to move limbs, and adopt different positions, but this is rather difficult where seating is cramped, such as in economy class. More generously proportioned seating leads to an increase in ticket price, and may in fact be resisted by those passengers seeking low cost travel.

US-A-5058954 describes a reclining seat/backrest which in the reclined condition offers little support against the occupant sliding down the inclined surface.

Furthermore the backrest moves rearwardly, and may encroach unacceptably on the occupant of the next rearward seat. In theory however this seat arrangement allows an occupant to straighten the legs.

US-A-5536067 describes a chair with a split seat pan, which may give better clearance for the upper thighs, yet retain sufficient support for the buttocks.

US-A-5722726 discloses a multi-component aircraft seat intended to permit the occupant to adopt a semi-reclined position.

US-A-6659552 proposes an inflatable seat portion which supports the lumbar region in an aircraft seat, and allows the occupant to straighten the legs.

US-A-7195316 is a mechanical substitute similar to US-A-6659522, and in which the seat back and seat pan move together to a reclined position without encroaching on the next rearward occupant. In order to allow leg space for the occupant, the seat pan is divided and the front portion hinges down. Thus this seat has a sloping backrest and short seat pan in the reclined condition, which permits an occupant to straighten the legs.

The latter proposal is mechanically complex, and has numerous movable components and pivots. There is also a risk of broken or damaged parts, for example the split seat pan may be uncomfortable in the normal position.

What is required is a lightweight and simple seat construction suitable for close seat pitch, and which permits an occupant to comfortably adopt different postures.

According to the invention there is provided a seat comprising a mounting, a seat pan on the mounting, a frame on the mounting, a backrest pivoted on the frame about a high transverse axis with respect to the seat pan, and a latch to restrain said backrest at a desired angular position relative to said frame.

In practice many occupants of economy seating tend to adopt a position in which the buttocks are forward on the seat pan, in order to try and straighten the legs; sometimes this forward positioning is inadvertent. The present invention allows the back to be supported in such a position, which is more comfortable for the occupant and has less risk of causing pain.

The mounting is provided for fixing the seat to a substrate, and the frame supports the backrest. The frame may be fixed with respect to the mounting, or may be relatively movable -for example as part of a seat reclining mechanism.

In one embodiment the seat pan is fixed; in such a seat, a moving backrest with a single pivot axis may suffice. The occupant selects a desired rake and latches the backrest to the seat frame. The rake may be changed on demand, and may provide a range of seat configurations from full sitting to semi-reclining.

In another embodiment the seat pan is movable in a generally fore and aft direction for example on a latchable sliding mechanism. In such arrangement the seat pan slides independently of the backrest.

In this arrangement, the seat pan length can be selected to give the degree of buttock support which the occupant desires.

In another arrangement a reclining seat is provided with a high pivot backrest according to the invention. In this configuration, the backrest may be moved forward in the reclined position of the seat to give a shorter seat pan length with greater reclining angle.

Preferably the transverse axis is above mid-height of the backrest, and most preferably above three-quarter height. A head rest may be provided on the seat back, or made integral therewith. For the purposes of this specification, a seat back terminates at average passenger shoulder height.

When latched close to the forward end of a seat pan, for example with 20% or less of the seat pan exposed, the seat permits semi-reclining of the occupant with the buttocks supported on the ledge provided by the exposed seat pan portion. In this position the occupant's back is supported and the occupant's legs are substantially straight, thus avoiding prolonged bending of the body at the pelvis which may give rise to lower back pain.

It will be understood that a seat according to the invention is relatively inexpensive compared with prior art proposals, and it can be mechanically simple. The high pivot seat allows a close seat pitch, as required in economy seating, and does not encroach upon the next rearwards row.

A further advantage of the invention is that the seat back may be adjusted for normal sitting with several different lengths of seat pan; thus the seat permits comfortable accommodation of both short and tall passengers.

Other features of the invention will be apparent from the following description of a preferred embodiment shown by way of example in the accompanying drawings in which:-Fig. I schematically illustrates a conventional aircraft seat; Fig. 2 illustrates a typical slumped seating position; Fig. 3 illustrates a seat according to the invention reclined in a configuration; Figs. 4 and 5 illustrate a seat according to the invention when seat in long and short seat pan configurations; Fig. 6 illustrates the invention with a movable seat pan; and Fig. 7 illustrates the invention provided on a reclining seat.

With reference to Fig. 1, a conventional aircraft seat 10 comprises a seat pan 11 and a backrest 12. Not shown in Fig. I is the usual seat frame, leg(s), armrests and headrest.

The seat frame supports the seat pan and backrest; typically in an economy seat, the seat pan is fixed, and the backrest is pivoted at the lower end to allow a limited amount of reclining (as shown in dotted outline 13).

As illustrated in Fig. 1, the backrest provides support for the occupant's back, and the seat pan provides support for the thighs. Necessarily, the length of seat pan (fore and aft) is a compromise and may not be comfortable for very short or very tall occupants.

Fig. 2 illustrates in somewhat exaggerated form a common posture adopted by an occupant during a long haul flight in an economy seat. The buttock region moves toward the front end of the seat pan in order that the occupant can straighten the legs 14, but as a consequence much of the occupant's back and spine region 15 is unsupported and thus may result in lower back pain.

The invention is illustrated in Fig. 3. The backrest 22 is pivoted on the seat frame at the high end; as illustrated a pivot axis 24 is at the very top of the backrest, but it need not be. The seat pan 21 is conventionally attached to the seat frame, and may be movable as further described below.

For take-off and landing, and if desired by the occupant, the backrest is fixed in a conventional upright position, as illustrated in dotted outline 24.

However, when permitted, the occupant may pull the lower end of the backrest 22 forward so as to permit full straightening of the legs 14 whilst ensuring that the back and spine region 15 is fully supported. The occupant's buttocks are supported by a short protruding portion of seat pan, typically 25% or less of the overall fore and aft length.

Any suitable means of latching the backrest can be used, for example spring loaded plungers on either side of the backrest may engage in rails having plunger receiving apertures at suitable spacings. The occupant merely moves to the front of the seat pan, and eases the backrest forward. A motorized motion is relatively simple to arrange since a single moving seat part is provided -for example a screw jack in either armrest may be sufficient.

Figs. 4 and 5 illustrate how the adjustable backrest allows a comfortable length of seat pan 26 for both tall (Fig. 4) and short (Fig. 5) occupants.

Fig. 6 illustrates a movable seat pan variant in which the seat pan 31 is slidable fore and aft. The seat pan is moved by the occupant, and is latchable at a desired fore and aft position. The backrest is independently latchable so as to give a range of seating positions. This arrangement allows a sloping backrest with a full length seat pan, at the expense of reduced leg room.

Fig. 7 illustrates the effect of the invention applied to a reclining seat of the kind usually provided for business class travellers.

Fig. 7a shows a reclining seat 41 in the upright condition, and Fig. 7b illustrates the high pivot backrest 42 in the rear and forward conditions.

Fig. 7c shows the seat 41 in the reclined condition, and Fig. 7d shows the effect of pivoting the high pivot backrest to give a shorter seat pan 43 with additional reclining of the backrest 42. It will be understood that in this embodiment the reclining mechanism of the seat incorporates the pivot frame of the backrest.

As is clear from the drawings, variation of backrest angle does not substantially reduce the space available for the next rearward passenger.

Although the invention has been described in relation to aircraft seats, it will be understood that it is applicable to transportation seating generally, and may also be suitable for buses, trains and the like.

L

Claims

Claims 1. A seat comprising a mounting, a seat pan on the mounting, a frame on the mounting, a backrest pivoted on the frame about a high transverse axis with respect to the seat pan, and a latch to restrain said backrest at a desired angular position relative to said frame.
2. A seat according to claim I wherein said frame is reclinable with respect to said mounting, and is latchable at a desired reclining angle.
3. A seat according to claim I or claim 2 wherein said axis is above the mid height of said backrest.
4. A seat according to claim 3 wherein said axis is above three-quarter height of said backrest.
5. A seat according to claim 4 wherein said axis is above 90% height of said backrest.
6. A seat according to any preceding claim wherein said seat pan is fixed with respect to the said frame.
7. A seat according to any of claims I to 5 wherein said seat pan is fixed with respect to said mounting.
8. A seat according to I wherein said seat pan is movable fore and aft independently of the backrest and has a plurality of latchable positions with respect to said frame.
9. A seat according to claim 8 wherein said seat pan is slidable.
10. A seat according to claim 1 wherein in the forward most position said backrest exposes 50% or less of the length of the seat pan.
11. A seat according to claim 9 wherein 25% or less of the length of said seat pan is exposed.
12. A seat according to any preceding claim wherein in the rearward most position the backrest exposes substantially the entire seat pan.
13. A seat substantially as described, and as illustrated in any of Figs. 3-6 of the accompanying drawings.