WO2009129992A1

WO2009129992A1 - Support structure for a seat assembly

Info

Publication number: WO2009129992A1
Application number: PCT/EP2009/002890
Authority: WO
Inventors: James Thompson
Original assignee: J Thompson Solutions Ltd
Priority date: 2008-04-21
Filing date: 2009-04-21
Publication date: 2009-10-29
Also published as: GB0807141D0

Abstract

A support structure for supporting a seat assembly or other structure upon a surface, said support structure comprising first and second laterally spaced support members (7, 8) extending between the seat assembly and the surface from first and second laterally spaced locations on the seat assembly and a third support member (9) extending between the seat assembly and the surface from the seat assembly at a third location on the seat assembly between and in front of or behind said first and second laterally spaced locations whereby the seat assembly is supported by the support structure at three locations.

Description

SUPPORT STRUCTURE FOR SUPPORTING A SEAT ASSEMBLY AT THREE LOCATIONS

Field of the Invention

The present invention relates to a support structure for supporting a seat assembly on a surface, especially for vehicle seats and most particularly for aircraft seats.

Background to Invention

Hereinafter, unless otherwise stated the terms "fore, "aft", "forward", "front", "rearward", "rear" and the like are used with respect to a seated passenger, who is assumed to face "forwardly". In the field of aircraft seating, part of the qualification of the seat design is that each seat unit must withstand predetermined static loading corresponding to forces applied to the seat during normal use and during impacts and must also accommodate deflection of the aircraft floor during impacts.

The typical multiple occupant seat unit is supported by four supporting members joined to the seat unit at four separate points, roughly corresponding to the four corners of the seat unit. The load distribution between the four supporting members can vary depending upon the load applied to the seat unit, for example depending upon the number and position of passengers on the seat unit. Such variation in loading can result in one or more of the supporting members bearing a greater load than the others, possibly resulting in an excessive load being borne by said one or more of the supporting members leading to failure of the connection between such supporting member or members and the floor, particularly in relation to the rearmost supporting members which must bear a substantial upward force tending to tear the supporting member from the floor in a forward impact.

Deflections of the floor are fed directly to the seat structure via the airframe mounting tracks and corresponding rigid connections to the seat structure. Conventional seating designs are such that adding pitch and roll causes pre-stress and correspondingly increases the loads experienced at certain mounting locations dependent upon the actual design. As a result this may have an adverse affect on the seat structure. It can also be said that with conventional seating designs, applying pitch and roll may have an adverse effect on structures and elements of the seat unit connected to said base structure. The resultant pre-stresses often have a detrimental effect on the attached furniture and impair the correct operation of associated assemblies.

The purpose of providing floor deformation during testing is to demonstrate that the seat unit will remain attached to the airframe and perform properly, even though the airplane and/or seat unit are deformed by the forces associated with a crash. Figure 1 depicts the pitch and roll tested in industry practice, typically 10° pitch of one airframe mounting track and 10° roll of the other track. This test requires simulating airplane floor deformation by deforming the test fixture, as respectively prescribed in Figures 1 and 2 for single occupant and multiple occupant seats, prior to applying forces corresponding to those experienced during dynamic impact conditions. The purpose of providing floor deformation for the test is to demonstrate that the seat/restraint system will remain attached to the airframe and perform properly, even though the airplane and/or seat are deformed by the forces associated with a crash. In Figures 1 , 2 and 2a, "A" shows the original position of the airframe mounting tracks and seat/seat frame prior art deformation of the floor while B shows the position of the airframe mounting tracks and seat/seat frame after deformation of the floor.

Summary of the Invention

According to a first aspect of the present invention there is provided a support structure for supporting a seat assembly or other structure upon a surface, said support structure comprising first and second laterally spaced support members extending between the seat assembly and the surface from first and second laterally spaced locations on the seat assembly and a third support member extending between the seat assembly and the surface from the seat assembly at a third location on the seat assembly between and in front of or behind said first and second laterally spaced locations whereby the seat assembly is supported by the support structure at three locations.

Preferably said third support member engages said surface at two laterally spaced locations thereon. The third support member may comprise a substantially inverted V or Y shaped structure extending between the seat assembly and the surface. Said third location at which the third support member is connected to the seat assembly may be selected to substantially equalise a load distribution between the first and second support members.

Preferably said third support member includes a flexible or hinged portion, substantially vertically aligned with said third location at which said third support member is connected to said seat assembly, said flexible or hinged portion permitting flexure or pivotal movement of the third member about a substantially horizontal axis extending in a fore-and-aft direction with respect to the seat assembly to allow the third support member to absorb deflections of surface upon which the support structure is mounted. In one embodiment said flexible portion may comprise one or more substantially vertical blade members arranged in a fore- and-aft direction. In an alternative embodiment said hinged portion may comprise a hinge member pivotal about said substantially horizontal axis arranged to transmit a vertical load from said seat assembly to said surface while permitting pivotal movement of said third support member transverse to said fore-and-aft direction.

Said first and second support members may extend between said seat assembly and said surface at an oblique angle. In one embodiment, said third support member may comprise a substantially central member, a respective laterally extending bridge member extending the central member in opposing directions downwardly at an oblique angle to engage the surface. Preferably central members comprises a tubular member extending in said fore- and-aft direction connected to the seat assembly via at least one longitudinally extending substantially vertical member extending in said fore-and-aft directions, said vertical member providing predetermined flexibility in the third support member about a horizontal axis extending in the fore-and-aft direction parallel to the axis of the tubular member. The bridge members may extend from respective ends of said tubular member in offset relationship in the fore-and-aft direction. Said first and second support members may also be offset from one another in a fore-and-aft direction.

According to a further aspect of the present invention there is provided a seat assembly including a support structure in accordance with the first aspect of the invention.

In one embodiment, the seat assembly comprises a multiple occupancy seat assembly comprising a plurality of seats arranged in a row. The seats may be displaced, or staggered, with respect to one another in the longitudinal direction, preferably to form a row that is obliquely disposed with respect to the longitudinal axis of the aircraft. The seats may be offset in a fore-and-aft direction and are arranged in partially overlapping relationship. The seat assembly is preferably a multiple occupant aircraft seat.

According to a further aspect of the present invention there is provided a seat base support structure comprising a plurality of linkage members defining a first substantially rigid connection between the seat base and the surface upon which the seat base is mounted and a second relatively flexible connection between the seat base and said surface, said second connection being laterally spaced from said first connection, whereby said relatively flexible second connection enables pivotal movement of said seat base structure relative to said first connection to readily absorb deflections of said surface.

Preferably said second connection comprises a linkage member extending from said seat base to said surface at an oblique angle. In one embodiment, said linkage members define a substantially central first connection and two second connections respectively provided at or adjacent the lateral sides of the seat base on either side of the first connection.

Accordingly, the invention incorporates a plurality of linked members which together act as the seat support structure. During a defined pitch and roll, the rigid connections of seat support structure to airframe track experience reactionary forces which are significantly converged, with the difference between said loads substantially balanced by the plurality of links.

The system of linked members is arranged such that the support structure will readily accept torsional deflections applied along the width of the seat. Considering the example of a 'double' seat, or one which is designed to accommodate two passengers, the links may be arranged such that, around the third support member between seat structure and mounting tracks, the support structure is flexible, pivoting about a defined point. This pivoting functionality may allow the load experienced by the mounting frame connections to converge towards similar or indeed same values. The inherent flexibility within the design readily absorbs airframe deflections, eliminating the pre-stresses in furniture directly connected to the seat base structure, and reduces the possibility of associated assemblies becoming inoperable. Description of the drawings

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 2 and 2a are front views depicting pitch and roll on a support structure for a seat assembly incorporating the invention.

Figure 3 is an isometric view of a seat support structure of Figure 2;

Figure 4 is a side view of the seat support structure of Figure 2; and

Figure 5 is a front view of the seat support structure of Figure 2.

Detailed description of the drawings

A seat support structure for supporting a multiple occupancy aircraft seat assembly embodying the invention is shown in the drawings.

The support structure is intended for supporting a multiple occupancy seat assembly of the type disclosed in EP 1461224 wherein adjacent seats in a row are offset in a fore-and-aft direction and overlap such that at least one of the left or right armrests of a first seat overlaps with the other of the left or right armrests of an adjacent seat, the extent of the overlap being such that each overlapping armrest extends beyond the armrest with which it overlaps. The seat assembly comprises a row of seats wherein, within each row, adjacent seats are displaced, or staggered, with respect to one another in the longitudinal direction to form a row which is obliquely disposed with respect to the longitudinal axis of the aircraft. However, the support structure is also suitable for supporting other types of seat assembly or other structures intended to be supported on a surface, such as vehicle seats, tables or other structures.

The support structure according to an embodiment of the invention includes a mounting structure forming the base of a seat assembly, the mounting structure comprising three laterally spaced substantially horizontally extending members 2,3,4 extending in the fore- and-aft direction, the members 2,3,4 being interconnected by substantially horizontally extending traverse linking members 5,6, 17, 18. The mounting structure is supported on a support structure comprising first and second laterally spaced rear support members 7,8 and a single front support member 9 such that the mounting structure is supported on the support structure at three spaced locations in the manner of a tripod. Each of the first and second rear support members 7,8 extend rearwardly from the mounting structure at an oblique angle to terminate in a respective rear mounting 13,14 for connected to a respective airframe track. The front support member 9 comprises a central tube 21 extending in said fore-and-aft direction connected to the mounting structure via two longitudinally aligned elongate vertical blade members 19,20 extending in said fore-and-aft directions to provide predetermined flexibility in the front support member about a horizontal axis extending in the fore-and-aft direction parallel to the axis of the central tube 21. A respective laterally extending bridge member 22,23 extends from each end of the tube 21 in opposing directions downwardly at an oblique angle to terminate in a respective front mounting 11 , 12 for connection to the respective airframe track. Respective front mountings 11,12 are linked to respective rear mountings 13,14 by bars to link the front and rear support members.

The mounts 13,14 at the rear of the seat structure may be pivotal in nature. The transverse linking members 17, 18 of the mounting structure add torsional rigidity above the connections of blade members 19, 20. In an alternative embodiment, the blade members 19, 20 could similarly be replaced with a single member or mechanical pivot dependent upon design requirements to provide the required degree of flexibility in the front support members 9. Rigidity in this area (in the vertical plane) is necessary in order to support passengers' weight and in order to provide suitable strength during the various in use and test demands. Flexibility to 'accept' pitch and roll is achieved through the joining of the blade members to the central torsion tube 21 to the seat structure and may also be enhanced by the connection of the central tube 21 to the bridge members 22, 23.

Considering worst case loading, in this instance, when the seat assembly carries a single passenger, balancing of the reactant loads or, at a minimum, the convergence of said loads between left 11, 13 and right hand 12, 14 mounts can be achieved by offsetting the tube 21 pivot point from the centre of the seat assembly. Thus the position of the central tube 21 and the connection of the blades 19,20 to the seat structure can be selected to optimise the load distribution between the left and right hand side mounts for all expected loading conditions.

Figure 4 shows a side view of the seat support structure. During pitch and roll, the relationship between the seat support structure to airframe mounts 11, 12, 13, 14 changes. Assuming that initially all four mounting points 1 1, 12, 13, 14 are sited on a horizontal plane, during pitch and roll the relationship changes, mounting point 12 may now be sited at a lower point. The resulting torsion within the frame is evenly distributed through the blade members 19, 20, central torsion tube 21 and bridge members 22, 23 due to the flexibility of third support member 9, preferably provided by the blade members 19,20, with minimal distortion of attached seat furniture.

As shown in figure 5, the bridge members 22, 23 of the front support member 9 form a balanced beam system, flexing around the central torsion tube 21 via the blade members 19,20. Reactant side loads experienced at seat structure to airframe connection 11, 12 can be reduced by incorporating a slot in each of the bridge members 22, 23 at the point where connection is formed to mountings 11, 12. During loading, this allows the downwardly deflection of the bridge members 22,23 to be absorbed via the mountings 1 1, 12 without transferring side loads.

The invention is not limited to the embodiments described herein but can be amended or modified without departing from the scope of the present invention.

Claims

1. A support structure for supporting a seat assembly or other structure upon a surface, said support structure comprising first and second laterally spaced support members extending between the seat assembly and the surface from first and second laterally spaced locations on the seat assembly and a third support member extending between the seat assembly and the surface from the seat assembly at a third location on the seat assembly between and in front of or behind said first and second laterally spaced locations whereby the seat assembly is supported by the support structure at three locations.

2. A support structure as claimed in claim 1, wherein said third support member engages said surface at two laterally spaced locations thereon.

3. A support structure as claimed in claim 2, wherein said third support member comprises a substantially inverted V or Y shaped structure extending between the seat assembly and the surface.

4. A support structure as claimed in any preceding claim, wherein said third location at which the third support member is connected to the seat assembly is selected to substantially equalise a load distribution between the first and second support members.

5. A support structure as claimed in any preceding claim, wherein said third support member includes a flexible or hinged portion, substantially vertically aligned with said third location at which said third support member is connected to said seat assembly, said flexible or hinged portion permitting flexure or pivotal movement of the third member about a substantially horizontal axis extending in a fore-and-aft direction with respect to the seat assembly to allow the third support member to absorb deflections of surface upon which the support structure is mounted.

6. A support structure as claimed in claim 6, wherein said flexible portion comprises one or more substantially vertical blade members arranged in a fore-and-aft direction.

7. A support structure as claimed in claim 6, wherein said hinged portion comprises a hinge member pivotal about said substantially horizontal axis arranged to transmit a vertical load from said seat assembly to said surface while permitting pivotal movement of said third support member transverse to said fore-and-aft direction.

8. A support structure as claimed in any preceding claim, wherein said first and second support members extend between said seat assembly and said surface at an oblique angle.

9. A support structure as claimed in any preceding claim, wherein said third support member comprises a substantially central member, a respective laterally extending bridge member extending the central member in opposing directions downwardly at an oblique angle to engage the surface.

10. A support structure as claimed in claim 9, wherein said central members comprises a tubular member extending in said fore-and-aft direction connected to the seat assembly via at least one longitudinally extending substantially vertical member extending in said fore- and-aft directions, said vertical member providing predetermined flexibility in the third support member about a horizontal axis extending in the fore-and-aft direction parallel to the axis of the tubular member.

11. A support structure as claimed in claim 10, wherein said bridge members extend from respective ends of said tubular member in offset relationship in the fore-and-aft direction.

12. A support structure as claimed in claim 11, wherein said first and second support members are offset from one another in a fore-and-aft direction.

13. A seat assembly including a support structure as claimed in any preceding claim.

14. A seat assembly as claimed in claim 13, wherein the seat assembly comprises a multiple occupancy seat assembly comprising a plurality of seats arranged in a row.

15. A seat assembly as claimed in claim 14, wherein the seats are displaced, or staggered, with respect to one another in the longitudinal direction, preferably to form a row that is obliquely disposed with respect to the longitudinal axis of the aircraft.

16. A seat assembly as claimed in claim 14 or claim 15, wherein said seats are offset in a fore-and-aft direction and are arranged in partially overlapping relationship.

17. A seat assembly as claimed in any of claims 13 to 17, wherein the seat assembly is a multiple occupant aircraft seat.

18. A seat base support structure comprising a plurality of linkage members defining a first substantially rigid connection between the seat base and the surface upon which the seat base is mounted and a second relatively flexible connection between the seat base and said surface, said second connection being laterally spaced from said first connection, whereby said relatively flexible second connection enables pivotal movement of said seat base structure relative to said first connection to readily absorb deflections of said surface.

19. A seat base as claimed in claim 18, wherein said second connection comprises a linkage member extending from said seat base to said surface at an oblique angle.

20. A seat base as claimed in claim 19, wherein said linkage members define a substantially central first connection and two second connections respectively provided at or adjacent the lateral sides of the seat base on either side of the first connection.