GB2561340A

GB2561340A - Seat anchoring system

Info

Publication number: GB2561340A
Application number: GB1704933.9A
Authority: GB
Inventors: Dunsford Mark; Kemp Nicholas; Clark Paul; Harrop Brett
Original assignee: Clarks Vehicle Conversions Ltd
Current assignee: Clarks Vehicle Conversions Ltd
Priority date: 2017-03-28
Filing date: 2017-03-28
Publication date: 2018-10-17
Anticipated expiration: 2037-03-28
Also published as: GB201704933D0; GB2561340B

Abstract

A seat anchoring system for a vehicle, comprising a track (21, figure 3) for mounting to a vehicle floor and comprising a pair of rails (22) each having forward (22f) and rear (22r) ends, and provided with a plurality of slots 24 extending in a longitudinal direction of the rails, defining one or more anchoring positions for a forward and/or rear facing seat (1f, 1r). The seat has a seat base comprising left and right side frames 11, each having a foot 12 comprising hooks 16 with hook openings 17 facing in the same, forward direction of the rails. Each hook is shaped to be dropped into a slot and for the seat to then be slid forward to feed regions 22a of the rails forward of the slots into the hook openings to anchor the seat in an anchoring position. Preferably, the hooks are integral continuations of the legs. During a collision or sudden braking, the hooks can therefore transmit tensile and compressive loads to the rails (22) directly from the side frames 11 and vice versa without the load having to pass across a welded joint or bracket. A method of anchoring a seat to vehicle is disclosed.

Description

(71) Applicant(s):

(56) Documents Cited:

EP 2252510 B1 US 20070018047 A1

US 20120273616 A1 US 20050211836 A1

Clarks Vehicle Conversions Limited (Incorporated in the United Kingdom)

Unit 16A, Carcroft Enterprise Park, Station Road, Carcroft, Doncaster, DN6 8DD, United Kingdom (58) Field of Search:

INT CL B60N, B61D, B63B, B64D Other: EPODOC. WPI (72) Inventor(s):

Mark Dunsford Nicholas Kemp Paul Clark Brett Harrop (74) Agent and/or Address for Service:

Dehns

St. Bride's House, 10 Salisbury Square, LONDON, EC4Y 8JD, United Kingdom (54) Title of the Invention: Seat anchoring system Abstract Title: Seat Anchoring System (57) A seat anchoring system for a vehicle, comprising a track (21, figure 3) for mounting to a vehicle floor and comprising a pair of rails (22) each having forward (22f) and rear (22r) ends, and provided with a plurality of slots 24 extending in a longitudinal direction of the rails, defining one or more anchoring positions for a forward and/or rear facing seat (1f, 1r). The seat has a seat base comprising left and right side frames 11, each having a foot 12 comprising hooks 16 with hook openings 17 facing in the same, forward direction of the rails. Each hook is shaped to be dropped into a slot and for the seat to then be slid forward to feed regions 22a of the rails forward of the slots into the hook openings to anchor the seat in an anchoring position. Preferably, the hooks are integral continuations of the legs. During a collision or sudden braking, the hooks can therefore transmit tensile and compressive loads to the rails (22) directly from the side frames 11 and vice versa without the load having to pass across a welded joint or bracket. A method of anchoring a seat to vehicle is disclosed.

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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Seat Anchoring System

Field

The present invention relates to a seat anchoring system for a vehicle.

Background

Seat anchoring systems for vehicles such as vans and minibuses are known. These usually comprise a system of rails, for example set into the vehicle as tracks, and detachable seats that can be fixed to the rails to anchor the seats within the vehicles. Usually a pair or set of parallel rails will extend longitudinally in the vehicle, typically in a region of the vehicle located behind the driver. For example, they may be fitted in a back of a van, but equally the seat anchoring systems may be used in other types of vehicles, not just land-based vehicles, and in other parts of the vehicle.

The rails have “forward” and “rear” ends as defined with respect to the forward direction of the vehicle (i.e., the normal driving direction of the vehicle). The seat may be a forward facing or a rear facing seat, this being defined with respect to the passenger and the direction of travel. It may be an individual seat designed for one person, or it may be a bench seat or multiple seats intended for more than one person. It may be a fixed seat or it may be a reclining seat having a mechanism that enables the seat back to be reclined.

Typically the seats will be provided with some form of passenger restraint system, usually in the form of a 3-point seat belt comprising a shoulder belt that is secured to a top corner of the seat back and extends across the passenger’s chest, and a lap belt extending across the passenger’s lap. The seats must meet certain vehicle safety standards and these include passing minimum loading tests aimed to mimic a vehicle collision. The provision of a shoulder belt means that any loading from a passenger during a head-on collision or sudden braking is taken through the shoulder belt fixing and needs to be transmitted to the floor of the vehicle through the seat. As this loading will be higher on a forward facing seat than a rear facing seat, the vehicle safety standards are set accordingly.

It has become popular to install such seats as a retrofit modification into existing vehicles, in particular vans, and there are a number of manufacturers that supply seat anchoring systems for this. One such system is the Jany van seat (http://www.jany.dk/index.php), which has a peg and key-slot anchoring system. The seats may also be installed in a new vehicle, either by the manufacturer or a vehicle dealership. For example, the rails of the seat anchoring system may be installed in the floor of the vehicle or a new sub-floor may be provided with integral rails and fitted to the vehicle.

While the current solutions meet certain commercial needs, there is a desire to provide an improved seat anchoring system for a vehicle.

Summary

When viewed from a first aspect, the present invention can be seen to provide a seat anchoring system for a vehicle comprising a track and a seat. The track is for mounting to a floor of the vehicle and comprises a pair of rails each having a forward end and a rear end. Additional rails may also be provided if desired. The rails are provided with a plurality of slots extending in a longitudinal direction of the rails to define one or more anchoring positions for a forward facing and/or a rear facing seat. The seat is adapted for anchoring to the track and it has a seat base which comprises left and right side frames spaced for alignment with the rails. Each side frame has a foot comprising formations configured to engage a rail.

According to preferred embodiments each side frame comprises forward and rear formations and at least the rear formations of the seat, and more preferably all the formations of the seat, are in the form of hooks which have hook openings facing in the same, forward direction of the rails. Each hook is shaped to be dropped into a slot of a rail and the seat to then be slid forward to feed regions of the rails forward of the slots into the hook openings to anchor the seat in an anchoring position.

In this way, by making sure that the seats are only mounted in one direction, an alternative anchoring system is provided which can be certified to meet vehicle standards and ensure that the seats are fitted in the manufacturer’s intended configuration, e.g., rear facing seats only in rear facing directions.

The hooks, as well as extending downwardly to engage the rails, may have a hook plane which preferably extends in the longitudinal direction of the rails. The hooks are preferably planar in that longitudinal direction.

In particular the hooks may be integral with, and have been formed from, structural material of the side frames. For example, they may have been laser cut from stock material used in the fabrication of the side frames. They may have the same thickness as the remainder of the structural material.

In one arrangement, at least the rear formations are hooks provided by continuations of sheet material, in particular integral sheet material of the side frames. In this way the loads during a head-on collision can be transmitted by tensile forces acting directly through the rear of the seat with the limit being the tensile strength of the sheet material. Preferably the forward formations are hooks too which have been formed in the same or a similar way to the rear hooks.

The sheet material may be folded to provide legs for the seat. The sheet material may also extend on one face to provide a panel that also functions to brace the side frames. It may provide vertically extending strips on the other face.

In another arrangement, the hooks may be provided by continuations of box sections which form legs for the seat base. The hooks may be continuations of one or two walls of the box section.

In both arrangements preferably the hooks have been formed by a laser cutting process.

The side frames may each provide a forward leg and a rear leg of the seat base. Each foot of the side base may be provided with a forward hook associated with a forward leg and a rear hook associated with a rear leg, and the forward and rear hooks may be arranged to engage the rails simultaneously as the seat is slid forward into its anchoring position.

The seat may be provided with at least four hooks to anchor the seat in the anchoring position, preferably six hooks, more preferably eight hooks.

The rails may comprise a box section having an upper rail section and a lower rail section.

At least the hooks at a forward end of the seat base, and preferably also the hooks at a rear end of the seat base, may be configured to provide a direct load path between the seat and the lower rail section for compressive forces.

By way of example, the forward hooks may be configured to position a lower jaw of the hook adjacent an underside of an upper rail section and to position a base of the hook adjacent an upper side of a lower rail section, so that in the anchoring position the forward hooks provide a load path for compressive loads to be transmitted from an upper jaw of the hook to the lower rail section via the upper rail section and the lower jaw of the hook. A similar set up may be provided for the rear hooks.

The track may define an anchoring position for a forward facing seat and an anchoring position for a rear facing seat. The seat anchoring system may further comprise a forward facing seat and a rear facing seat. Both seats may have formations in the form of hooks having openings facing in the same, forward direction of the vehicle to anchor the seats to the track.

In such an arrangement, a frame of a rear facing seat may be made from 20% lighter materials than the forward facing seat. Preferably it is lighter still and made from materials which are at least 30% lighter.

The seat anchoring system may comprise a floor panel for retrofitting into an existing vehicle.

The present invention also extends to a vehicle comprising a seat anchoring system as described above.

Viewed from another aspect, the present invention can be seen to provide a method of making a seat for use in the above described seat anchoring system, in which the hooks are formed by laser cutting structural material that provides the side frames.

In one example, the hooks are formed by laser cutting box section structural material that has been formed from sheet that has been folded and welded in a mill.

Viewed from a further aspect the present invention can be seen to provide a method of anchoring a seat in a vehicle. The method comprises: mounting to a floor of a vehicle a track comprising a pair of rails each having a forward and a rear end and each provided with a plurality of slots extending in a longitudinal direction of the rails to define one or more anchoring positions for a forward facing and/or a rear facing seat; and anchoring a seat to the track, the seat having a seat base which comprises left and right side frames spaced for alignment with the rails and each side frame having a foot comprising formations configured to engage a rail.

In preferred embodiments the method is based on the formations, at least at the rear of the seat, being in the form of hooks which have hook openings facing in the same, forward direction of the rails. More preferably the front formations are also hooks which have hook openings facing in the same, forward direction of the rails as the rear hooks. Each hook is dropped into a slot and the seat is then slid forward, feeding regions of the rails forward of the slots into the hook openings to anchor the seat in an anchoring position.

Preferably the hooks extend the full height of the rail. A base of the hooks may rest on an upper surface of a lower rail section of the rail as the seat is slid forward into the anchoring position.

The feet of the side frames may comprise plates with holes for fasteners to pass through.

The method may include securing the seat in the anchored position by passing fasteners through the holes and tightening the fasteners to secure the seat to the vehicle.

The hooks may be evenly spaced and correspond to the positions of the slots. The hooks may be dropped into the slots in the rails simultaneously, and the regions of the rails forward of the slots may be fed into the hook openings simultaneously as the seat is slid forward into the anchoring position.

Viewed from yet a further aspect, the present invention may be seen to provide a seat anchoring system for a vehicle comprising: a track for mounting to a floor of the vehicle, the track comprising a pair of rails each having a forward and a rear end and each provided with a plurality of slots extending in a longitudinal direction of the rails to define one or more anchoring positions for a forward facing and/or a rear facing seat; and a seat for anchoring to the track having a seat base which comprises left and right side frames spaced for alignment with the rails and each side frame having a foot comprising formations configured to engage a rail, wherein the rails comprise a box section having an upper rail section and a lower rail section and at least the formations at a forward end of the seat base, and preferably also the formations at a rear end of the seat base, are configured to provide a direct load path between the seat and the lower rail section for compressive forces. In this way the likelihood of the rail collapsing under load can be minimised, in turn reducing the likelihood of the rail buckling. This aspect may be combined with any of the above described desirable features. For example, the formations may be in the form of hooks.

Description of Figures

Certain preferred embodiments of the present invention will now be described in greater detail by way of example only and with reference to the accompanying drawings in which:

Figure 1A shows a perspective view of an exemplary reclining seat with one arm and some of the foam upholstery omitted for ease of viewing, and Figure 1B shows a perspective view of the same seat with the remaining upholstery omitted;

Figure 2 shows a perspective side view of an exemplary fixed (non-reclining) seat;

Figure 3 is a perspective side view from the forward end of an exemplary seat anchoring system, showing forward facing and rear facing seats anchored to a track;

Figure 4 is an enlarged perspective side view from the rear end of the track in Figure 3; Figure 5 is an enlarged perspective cross-sectional view showing how the seat in Figure 4 attaches to the rails of the track in an anchoring position;

Figure 6 shows a side view of the seat anchoring system of Figure 3 illustrating an arrangement of hooks for the forward facing and rear facing seats;

Figure 7 is an enlargement of the rear hook region of a forward facing seat and illustrates exemplary levels of stresses under loading;

Figure 8 shows a perspective view of a double track arrangement for a pair of forward facing seats and a pair of rear facing seats;

Figures 9A and 9B show perspective views of a further exemplary embodiment of the seat, with and without upholstery cushions respectively;

Figures 10A and 10B show a side view of the seat shown in Figure 9A and a close up of the hooks engaging a rail;

Figure 11 shows examples of different types of seat arrangement utilising the preferred seat anchoring system of the present invention;

Figure 12 shows a side elevation of two seats anchored facing opposite each other on a track; and

Figure 13 is a perspective view of three seats anchored to a triple track.

Figures 1A, 1B and 2 illustrate exemplary seats 1 for use in a seat anchoring system 20, such as the one shown in Figure 3. The seats 1 are forward facing seats, in the sense that they position the passenger in a forward facing position when the vehicle is travelling in its normal forward direction. The features of the seats 1 described below, however, apply equally to rear facing seats, i.e. seats which position the passenger in a rear facing position when the vehicle is travelling in its normal forward direction.

Figures 1A and 1B illustrate a reclining seat, firstly in Figure 1A with upholstery foam 2 present on the frame 3, and then in Figure 1B with the upholstery foam 2 removed for ease of understanding.

The frame 3 comprises the structural metalwork underlying the upholstery foam 2, a lower portion of which 3b provides a seat base 4 for the passenger to sit on and an upper portion of which 3a provides a seat back 5 to support the passenger’s back. The seat base 4 comprises side frames 11 which mount the seat 1 to the track of the seat anchoring system 20. The seat back 5 may have an integral headrest or a separate headrest (not shown) may otherwise be provided, as desired.

The upholstery foam 2 may be provided as foam cushions 6a, 6b, e.g., one cushion for the seat base 4 and one for the seat back 5 respectively. These cushions 6 are omitted from the view shown in Figure 1B.

The seat 1 of Figures 1A and 1B includes a pivot mechanism 7 on each side for reclining the seat back 5. It may be able to recline the seat back 5, for example, by up to around 30°, or by a different amount as desired. The seat 1 may additionally include an arm 8 on each side, which may be pivotable into a stowed position.

The upper portion 3a of the frame 3 may also include a mount 9 for a shoulder belt of a 3point seat belt (the seat belt is not shown in the figure). This mount 9 may project from the main part of the frame 3 to a position off to the left or right hand side of a passenger’s shoulder. It may include attachment features (e.g., holes, lugs, etc) for attachment of a reel (also not shown) which retracts the shoulder belt out of the way when it is not in use and which, more importantly, has a braking function to resist the forward motion of the passenger in the event of a head-on collision or sudden braking.

Figure 2 illustrates a non-reclining version of the seat 1 with the upholstery foam and possible seat arms 8 omitted for ease of understanding. The upper portion 3a of the frame 3 providing the seat back 5 is preferably continuous with the lower portion 3b of the frame 3 providing the seat base 4. The bend may be braced by a fixed angle bracket 3c, one on each side of the seat 1. This fixed angle bracket 3c may include a seat belt anchorage point 34, the bracket 3c helping to distribute loads from the seat belt into the frame 3 and to resist buckling as a result of the bending moment from the seat back.

In both versions of the seat 1, the lower portion 3b of the frame 3 (the seat base 4) comprises a left and a right side frame 11 which extend substantially vertically between upper and lower regions of the seat base 4. Each side frame 11 may comprise two or more upright frame members 11c, which may be of, for example, tubular or box section, and arranged to transmit load in the seat frame 3. In the embodiment of Figures 1 to 7, the upright frame members 11c are generally hidden from view through being clad on at least one face by sheet material 14a, 14b (as will be described in more detail below) which also serves a structural role in the side frame 3 of transmitting loads to other parts of the frame or to the rails and/or in bracing the side frame 11.

The side frames 11 may be configured to provide legs of the seat 1, namely a front leg 11a and a back leg 11b, the “front” and “back” being in relation to the seat itself (and not the direction of travel, e.g., as in the case of a rear facing seat - for a rear facing seat the “back leg” of the seat will be a “forward leg” as the term is used herein and the “front leg” of the seat will be a “rear leg”).

Thus, the seat 1 may comprise a pair of side frames 11 providing a total of four legs 11a,

11b as shown, with each leg 11a, 11b defining a corner edge of a substantially box-shaped seat base 4. Depending on the spacing of the rails, the side frames 11 may be stepped in within the footprint of the seat to form a sort of pedestal for the seat structure above. To provide more lateral stability, however, the side frames 11 are preferably located further out and extend downwardly to the rails from the upper side edges of the seat base 4.

The left side frame 11 is spaced with respect to the right side frame 11 for alignment with the rails of the seat anchoring system 20 (which will be described in more detail below). Crosspieces may be provided in the upper region of the seat base 4 joining the left and right side frames 11 and/or further down the seat base 4 to provide lateral bracing and support to the side frames 11.

The side frames 11 each comprise a foot 12 for anchoring the seat 1 to a rail of the seat anchoring system 20.

The foot 12 may include a generally flat, stable surface for fixing the seat 1 to the rail. In one example it includes a plate 12a, e.g. extending along a lower edge of the side frame 11, to link together the lower ends of the front and back legs 11a, 11b on a given left or right side. Holes 13 may be provided in the plate 12a for bolts (not shown) to pass through into the rail or floor structure to secure the seat 1 in its anchoring position. Such bolts may also provide some assistance with load transmission into the floor structure of the vehicle during a collision.

The left and right side frames 11 may include sheet material 14 provided in the form of a structural panel 14a and/or strip 14b. The sheet material 14 may be laser cut initially to a desired form and then folded to provide a continuous member providing a panel 14a bracing the legs 11a, 11b with respect to each other and providing a strip 14b bracing each leg 11a, 11b individually with respect to upper and lower regions of the seat base 4.

In an alternative arrangement, the sheet material 14, 14a, 14b may be arranged to clad front and rear upright frame members, at least on one face, and the combination of the sheet material and the upright frame members may then provide the legs 11a, 11b. Such upright frame members could comprise lengths of box section, the box section having been formed for example by extrusion or by folding and welding.

The sheet material 14, 14a, 14b may have several functions. It can provide a load path for distributing vertical (and other) loads within the frame 3, for example as compressive loads at the front of the seat base 4 and as tensile loads at the rear of the seat base 4 during a head-on collision or under heavy braking. It may also provide one or more hooks 16 which engage with the rails, and through such hooks the loads can be transmitted to and from the rails as will be described in more detail below. The sheet material 14, 14a, 14b may also provide a bracing function for the side frame 11 helping to maintain the alignment of the legs 11a, 11b with respect to the upper region of the seat base 4 and prevent the seat 1 collapsing under load. The panels 14a may include cutouts 15 to reduce weight, and the removed areas of sheet material 14 can then be used for other parts.

Arranging such structural sheet material 14, 14a, 14b in this way (e.g. a folded pre-cut sheet to provide a panel for the outer face of the side frames 11 and as strips for the inner face) allows the heads of the securing bolts to be hidden from view, while still allowing ease of access. However, if desired, the sheet structure 14 could be arranged the other way round. Moreover, it may be desirable to use two panels of sheet material 14a with a pair of upright frame members sandwiched between, or to use strips of sheet material 14b on both faces of such upright frame members for each side frame 11, or to use some further combination of structural sheet materials 14, 14a, 14b.

The side frames 11, and in particular the sheet material 14, 14a, 14b of these embodiments, may be a strong metal material, for example, having a yield stress of 200 Mpa or greater, and preferably as much as 450 MPa or greater, more preferably 600 Mpa or greater. The metal may be, for example, a steel, an aluminium alloy, a titanium alloy, or indeed any other suitable metal. It could also comprise a composite material, such as a carbon fibre composite, or a laminated material such as plywood, where sufficient strength is provided through sheet thickness to meet the appropriate vehicle safety standards for the seat’s intended purpose.

As can be seen in Figures 1A, 1B and 2, the sheet material 14, 14a, 14b continues below the level of the plate 12a to provide formations 16 that are configured to engage a corresponding rail of the seat anchoring system 20. The formations 16 may be in the form of hooks which are integral with the structural parts forming the legs 11a, 11b. The plane of the hook (the hook plane) may extend in the longitudinal direction of the rails, in line with the slots. The hooks 16 are preferably laser cut from the structural material providing the legs, and as such, can be seen to extend below the legs 11a, 11 b in a vertical plane which includes the longitudinal direction of the rails 22. A hook opening 17 of each hook 16 faces in the forward direction and engages a region 22a of the rail 22 forward of the slot 24 to anchor the seat in the anchoring position.

Such hooks 16, being continuations of the legs 11a, 11b, may have a substantially constant thickness corresponding to the thickness of the material that they are formed from e.g., panel 14a, strip 14b. The hooks 16 are preferably planar with the remainder of the material, though small deflections of up to ±5°, possibly even ±10°, may be possible without reducing strength significantly. Through being integral continuations of the legs 11a, 11b, the hooks 16 are able to transmit loads to the rails directly from the side frames 11 and vice versa without the load having to pass across a welded joint or bracket.

The hook openings 17 may be in the form of slots, which may be arranged to extend substantially horizontally when the seat 1 is fitted to the rails 22.

As can be seen in the figures, the hook openings 17 all face in the same direction; they all face in a forward direction of travel. As a result, the hooks 16 can be arranged to hook onto regions 22a of the rails 22 simultaneously when the seat 1 is slid in a forward direction.

In the embodiments of Figures 1 to 7, the hooks 16 are provided by continuations of the folded sheet material 14. In this way, a pair of hooks 16 may be provided for each leg 11a, 11b, the hooks 16 being arranged at the corners of the seat base 4 for anchoring the seat 1 to the corresponding rails of the seat anchoring system 20.

Thus, each leg 11a, 11b may be provided with two hooks 16, one on an outer face and the other on an inner face of each leg 11a, 11b. The two front legs 11a may provide four hooks to anchor the front of the seat 1. The two back legs 11b may, similarly, provide four hooks 16 to anchor the back of the seat 1. In total, there may be eight hooks 16.

Forming the hooks 16 as continuations of the structural sheet material 14, means that they will be planar with, and of the same thickness as, the parent sheet material 14. Tensile and compressive loads on the hooks 16 can be transmitted directly between the floor/rail and the sheet material 14 and then distributed into the rest of the frame 3; folds, welds or other fixing arrangements adjacent the hooks 16 that could create potential weaknesses in this part of the load path are thereby avoided.

If desired, other arrangements of formations could be used, e.g. to supplement some of the hook formations as desired, providing sufficient loads can be transmitted to the floor of the vehicle and the seat 1 retains its form in the event of a collision or sudden braking, as required to meet the requisite vehicle safety standard.

Preferably the strength of the parts and the arrangement of the frame 3 and rails 22 is such that compliance with a European vehicle category approval rating is achieved (e.g., as set out by ECE Regulation 14.07), for example, an “N1” or“N3” rating or, more preferably, an “M1” or “M3” rating or similar.

The hook openings 17, in addition to all facing in the same direction, may also be provided at the same level. The hooks 16 may also all be of the same size and have the same hook opening 17 profiles.

As will be described below, it is not essential that the forward and rear hooks 16 extend the same depth into the rails for the purposes of meeting vehicle safety standards, but it may provide other advantages, such as stability when the seats 1 are not mounted on the rails 22.

Figure 3 is a perspective view showing two seats 1 mounted to a track 21 of a seat anchoring system 20. The track 21 may comprise a pair of rails 22, which may be supported in a parallel configuration by a plurality of cross bars 23, e.g. four cross bars 23, this arrangement providing a type of ladder for the seats 1 to be mounted to. The cross bars 23 are preferably spaced at separations of less then 1.5m, more preferably less than 1m. The cross bars 23 help to brace the rails of the tracks (or the tracks with respect to adjacent tracks), distributing loads and helping to prevent buckling when loaded in a crash scenario. As shown in Figure 3, a pair of cross bars 23 may be positioned either side and close to where the seat base 4 is mounted, for example, within 200mm or more preferably 150mm of the seat base 4 to brace the rails 22 in this area.

By using a track 21 which runs under two seats as shown in Figure 3, the tracks 21 will help to stiffen the floor of the vehicle significantly, reducing the effect of the forward facing seat 1r locally distorting the vehicle floor under its front legs 14a during a head-on impact. In addition there is some synergy between the loadings of the forward and rear facing seats on the track 21 since the forward facing seat 1r will be trying to push down the central region while the rear facing seat 1f will be trying to lift it up.

As shown, the seats 1 may be arranged opposite one another on the track 21. The seat anchoring system 20 is directional and is configured so that the end 22f is a forward end (F) of the rail 22 and end 22r is a rear end (R) of the rail 22 respectively. The symbols “F” and “R” in the figures represent “forward” and “rear” accordingly for the vehicle in a normal driving direction. The forwardmost seat 1f is a rear facing seat, since a passenger would be facing towards the rear of vehicle, and the rearmost seat 1r is a forward facing seat, since a passenger would be facing towards the front of the vehicle.

Figure 4 is an enlarged perspective view of the rearmost seat 1 r. In the figure, it shows how the sheet material 14 may extend the full height of the seat base 4 and how the lower edge of the sheet material 14 may protrude below the level of the rail 22 to provide the hooks 16.

Each rail 22 may be provided with a plurality of slots 24 for receiving the respective hooks 16. The rear portion of the slots 24 can be seen in Figure 4 and the slots 24 themselves can be seen in cross-section in more detail in Figure 5. Depending on the number of hooks 16, there may be a corresponding number and placement of slots 24 to receive the hooks 16.

Also visible in Figure 4 are the holes 13 in the plate 12a for securing bolts. Holes 25 may also be provided in the ends of the rails 22 for securing them to a floor or other sub-frame of the vehicle.

Figure 5 shows a cross-sectional view through a rail 22 along the line of one set of the slots 24. The pair of hooks 16 are arranged so that they face in the same direction; the hook openings 17 open in the same direction. The hook openings 17 may be in the form of a profiled horizontal slot with upper and lower jaws 26a, 26b positioned to align with upper and lower surfaces of the upper rail section 27 of the rail 22. A layer of reinforcement 28 may be provided in the region of the slots 24 to provide a double thickness of material for the hook jaws 26a, 26b to grip onto.

The hooks 16 may have a generally rectangular or square outline with rounded corners as shown; in particular, the hooks 16 may have an extended and preferably flat lower edge 16a for abutment against a lower rail section 29. Forward and rear hooks 16 may have similar or identical outlines. The length of the hooks 16, when viewed from the side, may generally correspond to the length of the slots 24, the hooks 16 being slightly smaller to allow them to be dropped into the slots 24 during fitting. The hook openings 17 in each case may extend about 50% of the way across the hook 16, so that when the seat 1 is lowered to drop the hooks 16 into the slots 24, and then slid forward to feed the region of the rail forward of the slot 24 into the hook opening 17 to anchor the seat 1, the hooks 16 slide forward approximately half a slot length as the seat 1 moves into the anchoring position. Preferably the hook opening 17 extends between 30 to 60% of the hook length.

By way of example only, in one embodiment for a 50mm rail depth, the hook is generally centrally arranged with respect to the leg, and has a length in the direction of the rail of greater than 30mm, preferably more than 40mm, and most preferably around 45mm. The hook opening 17 may be greater than 15mm and the hook back (i.e., the narrowest part of the hook 16) may be greater than 15mm, more preferably greater than 20mm. The hook 16 may extend a distance below the hook opening 17 a distance greater than 35mm, more preferably greater than 40mm and more preferably still around 45mm corresponding to the internal separation of the upper and lower rail sections with a small amount of clearance to allow the parts to slide with respect to the other. A clearance of around 1mm (e.g., 0.51,5mm) may be provided at the bottom of the hook 16 between that edge and the upper face of the lower rail section. A similar clearance may be provided between the lower jaw and the lower surface of the upper rail section (including any reinforcement, if present). The hook may have a width or thickness of 2mm corresponding to the thickness of the parent sheet material.

In use, if there is a collision or sudden braking, then in a forward facing seat with a 3-point seat belt having a shoulder belt secured to a mount 9 on an upper portion of the back rest 5, the momentum from the top half of the passenger is transferred to the mount 9 and the upper region of the seat back 3a, causing a large forward moment (corresponding to the change in momentum of the passenger) about the front legs 11a of the seat base 4. This creates large tensile forces in the rear seat fixing, namely the rear hooks 16.

The hooks 16 may be provided by continuations of the sheet material 14, 14a, 14b as shown. In this way, tensile loads can be transferred from the hooks 16 directly into the sheet material 14 without having to pass through a join or bend (for example, in contrast with arrangements where an L-shaped bracket or attachment lug is provided to anchor a seat to a rail). From the sheet material 14, the tensile loads can be distributed into the frame 3. The folded panels or panels/strips of sheet material 14, 14a, 14b may be bonded to the rest of the frame 3 by welding, brazing, adhesive, etc., or they may be fixed with fasteners such as bolts, screws, rivets, etc. (face-to-face bolting), or a mixture of the two.

Slots 24 may be provided along the rails 22 as desired, for example, offering multiple positions.

However, more preferably the hooks 16 and the corresponding slots 24 are arranged so that the seats 1 can only be anchored to the rails 22 in set positions; in particular a single anchoring position for a rear facing seat 1f and a single anchoring position for a forward facing seat 1r.

A rear facing seat 1 may have to meet lower load criteria than a forward facing seat 1 because the momentum of a passenger during a collision or sudden braking is distributed into the whole length of the back rest 5 (rather than just the upper region where a shoulder belt of a 3-point seat belt is attached to the mount 9). As a result, it may be possible to make the seat frame 3 from lighter gauge materials and/or cheaper, lower strength materials and still meet the prescribed safety standards. To take advantage of this, by providing formations in the form of hooks 16 that can only sensibly engage the rails 22 in a particular direction, it is possible to ensure that the rear facing seats 1f are only ever installed as rear facing seats 1f. The position of the holes 13 in plates 12a for the securing bolts may also have a direction specific alignment with corresponding holes in the rails 22 so that the securing bolts can only be fitted when the seats 1 are facing in the correct direction.

By way of example, the forward facing seat 1r may have a wall thickness for the side frames 11 of 2mm thick and use 700 MPa yield strength steel, whereas for the rear facing seat 1 f, the wall thickness may be reduced to 1.5mm or possibly below 1.3mm and still achieve a required vehicle category approval rating such as an “N3”, or more preferably, an “M3” vehicle rating. Alternatively a lower grade of steel having a yield strength of 355 or 275 MPa could be used.

The hooks 16 may have set positions in the rails 22. There may be, for example, only sufficient slots 24 for a single forward facing and for a single rear facing seat 1 in specific positions. The anchoring system may be load tested with respect to specific rails 22 and the floor structure of specific vehicles. The seat anchoring system may be designed for a specific vehicle, where the loadings for the vehicle have been optimised accordingly for the structural properties of the vehicle floor panel. In this way it may be possible to supply vehicle-approved kits of mounted seats having fixed (approved) positions on particular tracks for pairs of direction-specific seats 1.

For each seat, there may be, for example, eight slots provided for eight hooks shared between the four feet 12 of the seat 1. The rail 22 may only have eight slots at a forward end of a track for a rear facing seat and eight seats at a rear end of the track for a forward facing seat. The position of the rear facing seat 1f and the forward facing seat 1r may then be set to meet a particular safety standard for a given vehicle. The spacing of the seats and the gauge/strength of the rails may be factors that are taken into account in the planning of the overall strength characteristics.

Preferably the spacing of the slots 24 is such that the seat anchoring system 1 is fool-proof and it is not possible to position additional seats or position the seats in a different position to that which is certified.

As shown in Figure 5, the hooks 16 may have a base 16a with a wide footprint that is substantially flat and positioned in close proximity with an upper surface of the lower rail section 29. In another possibility, rather than a trully flat surface, the base 16a may engage the lower rail section 29 by a series of protrusions of similar height. For both scenarios, in the event of a collision or sudden braking, when the seats 1 are under their maximum loading, the combination of the upper jaw 26a being in contact/close proximity with the upper surface of the upper rail section 27, the lower jaw 26b being in contact/close proximity with the lower surface of the upper rail 27, and the body of the hook 16 extending between the lower surface of the upper rail section 27 and the upper surface of the lower rail section 29, provides a load path or bridge for compressive loads. This minimises the likelihood of the rail 22 collapsing under load, maintaining the box-form shape of the rail 22 to reduce the likelihood of the rail buckling and thereby enhancing the overall load performance of the seat anchoring system 20.

This provision of a load path through the hook 16 is particularly important for the hooks 16 arranged at the forward end of the seats 1, where there is the greatest tendency to crush the rail 22. Where other types of formation are used in place of such hooks, preferably the forward formations are arranged in a similar manner, extending between the upper rail section 27 and the lower rail section 29 to provide a load path for compressive forces.

Preferably the hooks 16 arranged at the rear of the seat 1 are provided with a similar hook profile. While they may not need to provide a compressive force load path via the body of the hook 16 between the upper and lower sections of the rail 22 to resist crushing of the rails 22 since they will be in tension during a head-on collision or sudden braking, the same hook profile means that the seat 1 will have hooks 16 of the same height and will be stable when in storage.

The rails 22 may be formed from extruded box sections or folded and welded box sections. Preferably the sections have a wall thickness of 6mm or less, preferably less than 3mm, more preferably 2mm or less. The rails 22 may be reinforced locally around the slots 24 with an additional layer of material, e.g., a 2mm thick strip. They may be made from steel having a yield strength of around 700 MPa.

The rails 22 are preferably more than 30mm tall between the upper and lower rail sections 27, 29. In this way the rails 22 can also provide substantial reinforcement to the vehicle floor under the seats. In many of the prior art rail systems, while the rail thickness might be reasonably thick (e.g., 4mm or so), the rail height is generally quite shallow, roughly corresponding to the depth of a layer of thick plywood, for example, 18mm or so. In the present system, by making the rails 22 taller, the thickness of the rails 22 can be reduced so that weight is not increased, and a far stiffer beam can result through the improved second moment of area. The wall thickness may be reduced to 2mm or less, for example. As thinner walls are more prone to buckling than thicker walls, the preferred hook profile, e.g., where the base 16a of the forward hook 16 reaches to the lower rail section 29 or is close to that surface, may be used to provide a load path for the compressive forces and thereby resist localised buckling.

Preferably the upper and lower rail sections 27, 29 are more than 45mm apart. In certain embodiments the upper and lower rail sections may be up to or more than 60mm apart. For new vehicles where the rails 22 are fitted at source, it may be desirable to provide even deeper rails, for example, the rails 22 could be 75mm high, significantly adding to the structural properties of the vehicle floor.

The hooks 16 of the seats 1 may be sized according to the separation of the upper and lower rail sections 27, 29 to ensure transmission of compressive forces directly into the beam provided by the rails 22 and the braced structure of the track 21.

Figure 7 is an enlargement of the rear hook region of a forward facing seat 1f showing exemplary levels of stress around the hook 16 under test loading. The stresses were found to remain within working tolerances of the material with a generally uniform stress pattern (slightly higher stresses were seen towards the back of the hook opening 17 but these were well within the operating capability of the material).

Figure 8 shows a perspective view of a double track arrangement with the seats omitted. Two pairs of rails 22 are arranged side by side and joined by cross pieces 23a. As with the single track arrangement of Figures 3 to 6, longitudinal slots 24 are provided for receiving the hooks 16 of the seats 1. One position is provided in each track 21 for a rear facing seat 1f and for a forward facing seat 1 r. Holes 25 and 30 are provided for bolts for fixing the rails 22 and the seat 1 respectively to the vehicle.

Figures 9A shows a perspective view of another exemplary embodiment of the seat 1 and Figure 9B is a perspective view of the same seat with the upholstery cushions 6a, 6b removed.

A key difference in this embodiment is the structure of the seat base 4 and the side frames

11. In this embodiment the legs 11a, 11 b are provided by pre-formed, box section tubes that are then cut to shape in the workshop or factory, rather than folded sheet material 14 that has been cut in the workshop/factory prior to folding. The tubes, for example, are formed from high strength steel that has been folded and welded at the rolling mill to a high dimensional accuracy. These are then laser cut to form the hooks 16 and provide weightreducing cut outs 11c. In this way accuracy with the position and dimensions of the hooks 16 can be optimised, ensuring the repeatability of the seat’s mechanical performance.

Folding processes in a workshop or factory are unlikely to be as accurate as in a mill. Moreover the mechanical properties of the legs 11a, 11b can be optimised as the high quality mill properties are not altered; the manufacturer’s weld in the folded tube extends vertically, i.e., in the same direction as the principle stresses rather than across them so it does not present a weakness. The laser cutting process, as well as being extremely accurate, also results in less residual stresses than a conventional mechanical cutting or stamping process. This can be important for stress corrosion cracking and low cycle fatigue properties. Leg braces 14c of sheet material may be provided as shown in the upper and lower regions of the side frames 11 extending horizontally between the legs 11a, 11b.

In one example, the folded and welded box section used for the legs 11a, 11b has a yield strength of around 700 MPa and dimensions of 80 x 20 x 2 mm, though a smaller section could probably be used where available. The cut-outs 11c help to reduce the weight of the seat 1 and in the example shown reducing the weight by 750g.

Another difference is that a seat belt reel 31 is mounted to the underside of the seat area on a plate 32 joined to the frame 3. The shoulder belt extends from the reel 31 up the back of the seat 1 to a slotted hanger 33 provided on a mount 9 positioned close to the shoulder of the passenger, improving the appearance of the seat 1 by hiding the reel 31. A seat belt anchorage point 34 is also provided in the fixed angle bracket 3c for attachment of the other end seat belt fastenings.

All other features of the seat 1 are essentially the same as the fixed seat embodiment shown in Figure 2 and so further explanation on the common parts is omitted here for reasons of brevity.

Figure 10A shows the seat of Figure 9A from the side. In Figure 10B, a close up of a cross section through the rail 22 showing the engagement of the hooks 16 is shown. The hook profiles 16 are the same as previously described in relation to the embodiments shown in Figures 1 to 7.

As can be seen in Figure 10B a reinforcing layer 28 is provided on the underside of the upper rail section 27 to increase the rail thickness locally for engagement between the jaws 26a, 26b of the hooks 16. In some instances, it may be desirable to provide such local reinforcement on the topside of the upper rail section 27, though this could impact on the fitting of the seat 1 to the track 21 and, to an extent, the neat appearance of the track 21.

Figure 11 shows examples of different types of seat arrangement utilising the preferred seat anchoring system of the present invention. Moving from right to left in the figure there is shown (i) a triple seat arrangement on a triple track, (ii) a double seat rear facing and forward facing arrangement on a double track, (iii) a triple seat rear facing and forward facing arrangement on a triple track and (iv) a triple seat arrangement of two forward facing rows on a triple track.

Figure 12 shows a side elevation of two seats 1f, 1r in accordance with the exemplary embodiment of Figure 9A arranged opposite one other on a track 21 in a rear facing and a forward facing configuration. As can be seen, the hooks 16 and their respective hook openings 17 are arranged so that they all face the same forward (F) direction.

Figure 13 is a perspective view of triple seat configuration on a triple track where the seat 1 is based on the Figure 9A embodiment.

In addition to the variations described above with reference to the figures, other changes are of course possible within the scope of the invention. For example, the seat 1 instead of being a single seat 1 for a single occupant as shown in the figures, could be a double or larger capacity seat. It might, for example, be in the form of a bench seat for multiple passengers. Such a bench seat may comprise more than four legs and so be provided with more than eight hooks.

The vehicle receiving the seat anchoring system 20 might be a ‘convertible’ vehicle like a van, e.g., having a region immediately behind the driver for the seat or seats 1 where it might be desirable to remove the seats 1 at certain times. The van may be new or it may be an old one which is being converted to carry passengers in a region where seating was not originally provided.

The conversion or modification to the new/old vehicle may comprise a step of introducing a new floor or sub-floor structure into the vehicle comprising the track or rails 22. The seat anchoring system 20 may comprise providing a new floor panel for the vehicle comprising the rails 22, for example, in track form, and fitting the floor panel to a region of the vehicle for locating the new seating.

The method may comprise fitting a forward facing seat and a rear facing seat to a track 21 in a vehicle, by in each case lowering the formations of the seat 1, in particular hooks 16, into the slots of the rails 22 to anchor the seats 1 in position and securing the seats 1 by fitting bolts through holes 13 in the plates 12a of the seat feet.

Claims

Claims:

1. A seat anchoring system for a vehicle comprising:

a track for mounting to a floor of the vehicle, the track comprising a pair of rails each having a forward and a rear end and each provided with a plurality of slots extending in a longitudinal direction of the rails to define one or more anchoring positions for a forward facing and/or a rear facing seat; and a seat for anchoring to the track having a seat base which comprises left and right side frames spaced for alignment with the rails and each side frame having a foot comprising formations configured to engage a rail, characterised in that the formations are in the form of hooks which have hook openings facing in the same, forward direction of the rails, each hook being shaped to be dropped into a slot and the seat to then be slid forward to feed regions of the rails forward of the slots into the hook openings to anchor the seat in an anchoring position.

2. A seat anchoring system as claimed in claim 1, wherein the hooks are integral with, and have been formed from, structural material of the side frames.

3. A seat anchoring system as claimed in claim 1 or 2, wherein the hooks are provided by continuations of sheet material, and preferably where the sheet material also functions to brace the side frames.

4. A seat anchoring system as claimed in claim 3, wherein the sheet material has been folded to provide a panel on one face of the side frame and vertically extending strips on the other.

5. A seat anchoring system as claimed in claim 1 or 2, wherein the hooks are provided by continuations of box-sections forming legs for the seat base.

6. A seat anchoring system as claimed in any preceding claim, wherein the hooks have been formed by a laser cutting process.

7. A seat anchoring system as claimed in any preceding claim, wherein the side frames each provide a forward leg and a rear leg of the seat base, each foot is provided with a forward hook associated with a forward leg and a rear hook associated with a rear leg, and the forward and rear hooks are arranged to engage the rails simultaneously as the seat is slid forward into its anchoring position.

8. A seat anchoring system as claimed in any preceding claim, wherein the seat is provided with at least four hooks to anchor the seat in the anchoring position, preferably six hooks, more preferably eight hooks.

9. A seat anchoring system as claimed in any preceding claim, wherein the rails comprise a box section having an upper rail section and a lower rail section, and wherein at least the hooks at a forward end of the seat base, and preferably also the hooks at a rear end of the seat base, are configured to provide a direct load path between the seat and the lower rail section for compressive forces.

10. A seat anchoring system as claimed in claim 9, wherein the forward hooks are configured to position a lower jaw of the hook adjacent an underside of an upper rail section and to position a base of the hook adjacent an upper side of a lower rail section, so that in the anchoring position the forward hooks provide a load path for compressive loads to be transmitted from an upper jaw of the hook to the lower rail section via the upper rail section and the lower jaw of the hook.

11. A seat anchoring system as claimed in any preceding claim, wherein the track defines an anchoring position for a forward facing seat and an anchoring position for a rear facing seat, the seat anchoring system comprises a forward facing seat and a rear facing seat, and wherein both seats have formations in the form of hooks having openings facing in the same, forward direction of the vehicle to anchor the seats to the track.

12. A seat anchoring system as claimed in claim 11, wherein a frame of the rear facing seat is made from 20% lighter materials than the forward facing seat, preferably 30% lighter materials.

13. A seat anchoring system as claimed in any preceding claim comprising a floor panel for retrofitting into an existing vehicle.

14. A vehicle comprising a seat anchoring system of any preceding claim.

15. A method of making a seat for use in the seat anchoring system as claimed in any preceding claim, wherein the hooks are formed by laser cutting structural material that provides the side frames.

16. A method as claimed in claim 15, wherein the hooks are formed by laser cutting box section structural material that has been formed from sheet which has been folded and welded in a mill.

17. A method of anchoring a seat in a vehicle comprising:

mounting to a floor of a vehicle a track comprising a pair of rails each having a forward and a rear end and each provided with a plurality of slots extending in a longitudinal direction of the rails to define one or more anchoring positions for a forward facing and/or a rear facing seat; and anchoring a seat to the track, the seat having a seat base which comprises left and right side frames spaced for alignment with the rails and each side frame having a foot comprising formations configured to engage a rail, the method being characterised by the formations being in the form of hooks which have hook openings facing in the same, forward direction of the rails, wherein each hook is dropped into a slot and the seat is then slid forward, feeding regions of the rails forward of the slots into the hook openings to anchor the seat in an anchoring position.

18. A method as claimed in claim 17, wherein a base of the hooks rests on an upper surface of a lower rail section of the rail as the seat is slid forward into the anchoring position.

19. A method as claimed in claim 17 or 18, wherein the feet of the side frames comprise plates with holes for fasteners to pass through and the method includes securing the seat in the anchored position by passing fasteners through the holes and tightening the fasteners to secure the seat to the vehicle.

20. A method as claimed in claim 17, 18 or 19, wherein the hooks are dropped into the slots in the rails simultaneously, and the regions of the rails forward of the slots are fed into the hook openings simultaneously as the seat is slid forward into the anchoring position.

Intellectual

Property

Office

Application No: GB1704933.9 Examiner: Mr Ilya Gribanov