GB2292676A

GB2292676A - Reclinable seat for passenger-carrying vehicles

Info

Publication number: GB2292676A
Application number: GB9417660A
Authority: GB
Inventors: John Williamson
Original assignee: Flight Equipment and Engineering Ltd
Current assignee: BE Aerospace UK Ltd
Priority date: 1994-09-02
Filing date: 1994-09-02
Publication date: 1996-03-06
Anticipated expiration: 2014-09-02
Also published as: GB2292676B; GB9417660D0

Abstract

A reclinable seat for a passenger-carrying vehicle comprises a support frame 1 - 5 with a bottom part 8 slidably mounted on it for fore-and-aft movement a backrest 9 pivotally mounted on the frame on a transverse axis 10 above the bottom part and pivotally connected adjacent to its lower and 11 by links 12 to the rear of the bottom part so that reclining movement of the backrest causes the bottom part to slide forwardly with respect to the frame, the bottom part and the frame having co-operating cam 16, 17 and follower parts 4, 5 to cause the rear of the bottom part to be lowered and/or the front of the bottom part to be raised as the backrest is reclined and vice versa. <IMAGE>

Description

DECLINABLE SEAT FOR PASSENGER-CARRYING VEHICLES A seat in a passenger-canying vehicle which is likely to be occupied for long periods is usually provided with a reclinable backrest so that a passenger can change the backrest position and thus his attitude in the seat from time to time. Thebackrestis usually pivoted at or near its lower end to the seat frame or the bottom pan of the seat. The bottom part usually does not move during movement of the backrest, though reclining seats are known, for example as described in the Specification of our European Patent No. 0 107 882, in which the backrest and bottom part move together.

A problem with the usual arrangement, particularly for short or slight people occupying a seat or if an adequate foot rest is not provided, is that as the backrest is reclined there is a tendency for the seat occupant to slide forwardly in the seat. That is because the force produced by the backrest in reaction to the weight of the occupant has a forward component which increases progressively as the bacitrest is inclined rearwardly from its initial more or less upright position. If there is no footrest or the occupants feet do not have a good frictional grip on the floor of the vehicle, an occupant can slide right out of a seat, even if a seat belt is correctly fitted and worn.If there is a footrest or if the occupants feet engage the noor so that he is able to resist the forward component of the force, the strain in the leg muscles can cause discomfort. The invention aims to avoid or reduce the problem.

According to this invention a reclinable seat tor a passengefrcariying vehicle comprises a support frame, a bottom part slidably mounted on the flaLme for fore-and-aft movement relative thereto and a backrest pivotally mounted on the frame to pivot about an axis transverse with respect to the frame and above the bottom part and pivotally connected at or adjacent to its lower end to a rearward portion of the bottom part, whereby reclining movement of the backrest causes the bottom part to slide forwardly with respect to the frame, the bottom part and the frame having cooperating cam and follower parts to cause the rear of the bottom part to be lowered and/or the front of the bottom pan to be raised as the backrest is reclined and uce verso.

The lowering of the rear aud/or raising of the front of the bottom part as it slides forwardly on reclining the backrest increases the support of the body of an occupant of the seat against forward movement.

Preferably there are two cams and respective followers so that on reclining movement of the backrest both the rear of the bottom part is lowered and its front is raised An embodiment of the invention is illustrated by way of example by the accompanying drawings, m which: Figure 1 is a diagramatic side elevation of a seat for use in a pauenger-carrying aircraft, showing the backrest in full line in an upright position and in broken line in a reclined position, Figure 2 is a side view to a somewhat larger scale, showing components of the seat in their positions corresponding to the upright position shown in Figure 1, and Figure 3 is a view similar to Figure 2 showing the components in their positions corresponding to the reclined position shown in Figure 1.

The seat comprises a support frame including front and rear leg structures 1,2 pined by a floor strut 3 and carrying transverse beams 4, S which are joined by side members 6, each of which carries an armrest 7.

A bottom part 8 is slidably mounted on the beams 4, 5 for fore-and-aR movement relative to them. A backrest 9 is pivotally mounted between the side members 6 on pivot pins 10 located in the side members some distance above the bottom part 8 and rearwardly of its rear end. Extensions 11 at each side of the backrest 9, beyond the pivot pins 10, an connected by links 12 to the sides of the bottom part 8, as shown in Figures 2 and 3. The extensions 11 normally move rigidly with the backrest 8 about the pivot pins 10.The extension 11 nearest to the viewer in Figure 1 is also connected to the end of an oleo-pneumatic control device 13 of the usual kind which is mounted on the side member 6 and has a valve control button (not shown) in the armrest 7 enabling an occupant of the seat to set the position of the backrest 9 at any position between an upright position shown in full lines and a reclined position shown in broken lines. The construction and working of such a unit is well known.

From a study of Figure 1 it may be appreciated that when the backrest 9 is moved from its upright position shown in full line to its reclined position shown in broken line, it rotates on the pivot pins 10 and the bottom part 8 will be pushed forwardly by the links 12. If the bottom part 8 is then pushed rearwardly the backrest 8 will be swung forwardly to its upright position again. An occupant of the seat may, by exerting appropriate forces on the anarests, the floor of the vehicle or a footrest if provided and the backrest and bottom pall, produce these movements after releasing the valve of the control device 13.

There are frictional connections between the backrest 9 and the extensions 11 which are such that the extensions normally rotate together with the backrest about the pivot pins 10 as described. If during severe deceleration, for example in a crash situation, a forward force greater than a predetermined maximum is applied to the top of the backrest 9 that will overcome the frictional connections and allow the backrest to "break" forward about the pivot pins 10 in the usual way. Provision may also be made for the frictional connections to be released manually so that the backrest may be folded forwardly when desired.

The bottom part 8 comprises a cushion 14 supported on a rigid seat pan 15 as usual. Figure 2 shows diagramatically how an extension 11 is connected by a link 12 to the side of the seat pan 15, the parts being in positions conesponding to the upright position of tbe backrest 9 shown in full lines in Figure 1. Secured to the undenide of the seat pan 15 near its front and rear edges are cams 16, 17 which rest respectively on the front and rear beams 4 and S which, in this embodiment, serve as followers for the cams. The cam 16 it shallow at its front end and deep at its rear end and the cam 17 hat the convene shape, deep at its front end and shallow at its rear end.Due to these shapes. when the seat pan 15 is moved forwardly by reclining the backrest 9, the front of the seat pan is raised and its rear end is lowered. Figure 3 shows the fully reclined position, corresponding to the position shown in broken line in Figure 1. A strap 18 is secured to the front and rear of the cam 17 and passes round the beam 5 to prevent the seat rotating forwardly about the line of contact of the cam 16 with the beam 4, for example in the event of severe deceleration of the vehicle.

The upward inclination of the seat pan and thus the seat cushion by the action of the cams when the backrest 9 is reclined helps to prevent an occupant of the set fmm slipping forwardly in the seat. That is because the supporting forme produced hy the bottom pan in reaction to the weight of the seat occupant hat a n'arward component when the bottom part is tilted upwardly and that counteracts the previously-mentioned forward component of the reaction force from the baduat. The profiles of the cams may be designed to produce the desired inclination and maximum comfort for an occupant of the seat. If deseed, either the front cam 16 or the rear cam 17 may be omitted and all the desired Inclination be provided by one cam. Instead of using the beams 4 and 5 as followers, separate followers may be mounted on the frame.

Although the embodiment described is a single seat with the backrest 9 pivoted between side members 6, the invention is equally applicable to seating Units comprising seats for two or more occupants abreast, with an intermediate longitudinal frame member, parallel to the side members, between each pair of adjacent seats. In such a unit the pivot pins for the bactrests would be located in the side members and the intermediate longitudinal frame members.

Claims

1. A reclinable seat for a passenge-carrying vehicle comprising a support frame, a bottom part slideably mounted on the support frame for fore-and-aft movement relative thereto and a backrest pivotally mounted on the fame to pivot about an axis transverse with respect to the frame and above tile bottom part and pivotally connected at or adjacent to its lower end to a rearward portion of the bottom part, whereby reclining movement of the backrest causes the bottom part to slide forwardly with respect to the frame, the bottom part and the frame having co- operating cam and follower parts to cause the rear of tbe bottom part to be lowered andlor the front of the bottom part to be raised as the baclaest is reclined and ice versa.

2. A reclinable seat as claimed in claim 1 when tbe bottom part and the fame have two cams and aFquing follower parts adjacent fspecdvely to the front and rear of the bottom part whereby the forward sliding of the bottom part during reclining movement causes tbe rear oi the bottom part to be lowered and its front to be waised.

3. A declinable seat as claimed in claim 1 or claim 2 wherein the support frame comprises two parallel transverse beams canied by a leg structure and one or each of the transverse beams is or carries a follower part to perate with a cam on the bottom part.

4. A reclinable seat as claimed in claim 1 or claim 2 wherein the support frame comprises two parallel transverse beams carried by a leg structure and one or each of the transverse beams is or canies a cam to co-operate with a follower on the bottom part.

S. A reclinable seat for a passenger-carrying vehicle, substantially as hereinbefore descn'bed with reference to and as illustrated by the accompanying drawings.