A vehicle seat

Abstract

A passenger seat comprises a frame base 7 fixedly coupled to a vehicle and a swivel base (12,fig.2) rotatably coupled to the frame base about a vertical first axis (1,fig.2). The seat further comprise

Description

FIELD The present invention relates to a vehicle seat arrangement comprising an adjustable back rest to accommodate both adult and child occupants. The arrangement is pivotably fixed to a vehicle such that it can be rotated and stored in a compact orientation. BACKGROUND Seatbelts restrain an occupant inside a vehicle and prolong the duration of a sudden decelerating event on the occupant. Seat belts also aim to reduce instances of secondary impact, where an occupant collides with internal structures in a vehicle. Whilst seatbelts systems are highly effective, they are not always suitable for infants. Seat belt systems in vehicles are generally sized and oriented to effectively restrain adults but not well suited to properly restrain children. Accordingly, children often require supplementary devices, such as booster seats which elevate a child to receive a safety harness correctly. Some supplementary devices for smaller children are secured to the vehicle by anchors and / or harnesses and the supplementary device provides further harnesses to secure the child. It is widely accepted that a rearward facing seating position is the safest way for infants to travel in a vehicle. Vehicles typically travel most quickly in the forward direction and therefore abrupt decelerating forces are most likely to act in the backward direction. As such, it is advantageous to apply deceleration forces to the body through the back rest of a seat to distribute the force across a larger area than the typical cross-section of a seat belt. The head of the infant can also be supported by a back rest, reducing the extreme loads on the neck, induced during rapid deceleration, while seat belts generally restrain only the lap and torso. UK and European law dictates that infants must use a rear-facing car seat until they are 15 months old. It is therefore not only desirable to carry an infant in a rearward-facing seat, it is a legal requirement. Outside of personal private motor vehicles (such as cars), there still exists a benefit and legal requirement to carry an infant in a rearward facing position. However, in large occupancy vehicles (such as buses) or utility vehicles (such as ambulances), it can be more challenging to install bulky supplementary devices to facilitate a rearward facing seating position. Substituting more widely useful forward-facing seating for rearward-facing seating is not an optimal solution. Additional dedicated seating for infants or children is particularly challenging to provide given the objective to maximise space for additional equipment and maintain the utility and flexibility of vehicle internal space. It is therefore an object of the present invention to provide a seat with both a forward facing configuration, and a rearward facing configuration which is suitable for infants. It is also an object of the present invention to provide a seat which can be stored inside a vehicle to maximise the versatility of the internal vehicle space. WO03066370A1 discloses a passenger seat for a conveyance, comprising a frame, which is fixed to a floor of the conveyance, and a back rest, which is connected to the frame. On the rear of the back rest is mounted a folding seat, which has a sitting portion, and which is mounted on the back rest, thus enabling the folding seat to be tilted about a first axis of rotation between a folded-up position and a folded down position. The folding seat has a first eccentric portion, which is eccentric relative to the first axis of rotation. The frame has a second eccentric portion which is eccentric relative to a second axis of rotation. The back rest is mounted on the frame thus enabling it to be tilted about the second axis of rotation between a rear position and a front position. The passenger seat comprises a rod, whose end portions are hinged to the first eccentric portion and the second eccentric portion respectively. BRIEF DESCRIPTION OF THE INVENTION Features of the invention are set out in claim 1. Preferred features of the invention are set out in the dependent claims. BRIEF DESCRIPTION OF THE FIGURES In orderthatthe present disclosure may be more readily understood, preferable embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows an isometric view of the passenger seat in a first configuration. Figure 1a shows a side view the passenger seat in the first configuration. Figure 1 b shows a front view the passenger seat in the first configuration. Figure 1c shows an isometric view of the passenger seat in a first configuration, with the padded regions removed. Figure 1d shows a side section view of the passenger seat in a first configuration, with the padded regions removed. Figure 1e shows a side view of the passenger seat in a first configuration, with the padded regions removed. Figure 1f shows a side view of the passenger seat in a first configuration, with the padded regions removed. Figure 1g shows a bottom view the passenger seat in the first configuration. Figure 2 shows and isometric view of the swivel base. Figure 3 shows and isometric view of the swivel base. Figure 4 shows and isometric view of the swivel base. Figure 5 shows an isometric view of the passenger seat in a second configuration. Figure 5a shows a side view the passenger seat in the second configuration. Figure 5b shows a front view of the passenger seat in the second configuration. Figure 5c shows a side view of the passenger seat in a first configuration, with the padded regions removed. Figure 5d shows a side view of the passenger seat in a first configuration, with the padded regions removed. Figure 5e shows a side section view of the passenger seat in a first configuration, with the padded regions removed. Figure 6 shows an isometric view of the passenger seat in a third configuration. Figure 6a shows a side view of the passenger seat in a third configuration. Figure 6b shows a bottom view of the passenger seat in a third configuration. DETAILED DESCRIPTION OF THE DISCLOSURE Figures 1 and 1a-g show a passenger seat 100 in accordance with the invention, in a first configuration. The passenger seat 100 comprises a frame base 7, suitable to be coupled directly to a vehicle; a swivel base 12, which is rotatably coupled to the frame base 7 at a vertical first axis 1; a first squab 22 rotatably coupled to the swivel base 12 at a horizontal second axis 2; and a back rest 27, with first and second back rest surfaces 30, 31 on opposing sides, rotatably coupled to the swivel base 12 at a horizontal third axis 3; and a second squab 37 rotatably coupled to the back rest 27 at a horizontal fourth axis 4. The passenger seat 100 has a forward direction, which is generally the direction in which the first back rest surface 30 faces. In the first configuration shown in Figures 1 and 1 a-g, the passenger seat 100, back rest 27, and first squab 22 are oriented to accommodate a passenger, such as an adult passenger, in a seated position and facing in the forward direction. The first squab 22 is substantially horizontal, the back rest 27 is substantially vertical, and the second squab 37 (not visible in Figure 1) is folded adjacent the rear surface of the back rest 27. The frame base 7 forms the interface between the passenger seat 100 and the vehicle. The frame base 7 is suitable to be coupled to a vehicle and facilitate rotation of the swivel base 12 about a vertical axis. The frame base 7 is preferably made of robust material such as steel. The frame base 7 is further visible in in Figures 2-4 and in Figures 1g and 6b. The frame base 7 may, for example, be fixed to a cantilever protruding from a vehicle wall, or to a pedestal protruding from the floor of a vehicle. In further examples, the frame base 7 is set at or near floor level. The frame base 7 can be seen most clearly in Figures 1g, 2, 3, and 6b. In the example shown, the frame base 7 is a plate with an upper surface 15 and a lower surface 16. In this example the frame base 7 takes a shape that is generally circular, with two segments defined by two equal length chords at right angles removed from the circular shape. The removed material from the otherwise circular shape may allow the plate to abut one or two flat structures such as walls, rails or the like. The frame base 7 may take any suitable planar shape such as square, rectangular, semicircular, triangular, or any shape arising from rounding the corners of these shapes. The depicted plate comprises four holes spaced in a square formation to receive fasteners to secure the plate to a vehicle. The holes are located near the periphery of the plate. Preferably the holes are equally spaced from the centre of the plate. In other examples three, four, five, six or more holes may be advantageous to receive fasteners. The plate shown in the figures comprises a central hole 8 to receive suitable shafts, bearings, bushes or the like to allow the adjoined swivel base 12 to rotate with respect to the frame base 7 and therefore rotate with respect to the vehicle. Alternatively, there may be a centrally protruding shaft suitable to be received by a bearing, bush, or the like on the swivel base 12. One or more concentric features 9 such as slots and / or grooves are preferably formed in the frame base 7 to provide additional axial location for the swivel base 12. The concentric features 9 are preferably of limited length to constrain rotation to within an intended range. In such embodiments one or more protrusions (not shown) are received within the or each concentric feature 9, to prevent rotation of the frame base 7 beyond the desired limits. Optionally, the concentric features 9 extend the full 360 degrees around the centre. The frame base 7 comprises two or more radial indexing features 10. In the example shown the indexing features are suitable to interface with a swivel plunger 19, which is fixed to the swivel base 12, at desired angular intervals. Each interval corresponds to an angle of the swivel base 12 with respect to the frame base 7 about the first axis 1. In the embodiments shown, the radial indexing features 10 are location slots 10 formed in an outer edge of the plate, spaced apart from each other, for instance by 90 degrees. The edges where the location slots 10 (or other radial indexing features 10) meet the outer edge of the frame base 7 may be rounded to more easily accept the swivel plunger 19. It is contemplated that the radial indexing features 10 may be arranged at any appropriate angular intervals on the plate edge, upper surface 15, or lower surface 16 of the frame base 7. The indexing features may take the form of holes, slots and / or indentations angularly spaced about the central hole 8. Alternatively, the inverse arrangement is possible with the radial indexing features 10 of the frame base 7 being a series of protrusions, suitable to be received by corresponding indentations in the swivel base 12. Preferably, the protrusions would be biased to protrude into respective slots by a spring or an alternative elastic component. The frame base 7 of the passenger seat 100 may comprise one or a series of protrusions to be received by holes, tracks or the like in a vehicle body. The frame base 7 may also comprise one or more protrusions to be received by holes, tracks, or the like in the swivel base 12. The frame base 7 may take the form of multiple plates, each preferably secured to the vehicle separately. The radial indexing features 10 may be formed in any one of the plates. The frame base 7 may comprise multiple coaxial plates secured to the vehicle by the same set or a different set of fasteners. The plates may rotate with respect to one another about a common shaft, with one plate fixed and suitable to rotate with the swivel base 12, and another suitably to be fixed to the body of a vehicle. A suitable slidable interface between the two plates would be required such as ball bearings. The frame base 7 may comprise one or more legs protruding from a plate which are suitable to be received in one or more rails in a vehicle body. Optionally, the legs are suitable to engage with curved rails to allow the passenger seat 100 to rotate with respect to the vehicle. The legs and / or rails may include a plurality of wheels to facilitate smooth movement of the legs in the rails. It is contemplated that one or more legs may protrude from the vehicle to be received by slots or indentations in the frame base 7. The one or more legs would be free to translate within the slots or rails to allow the passenger seat 100 to rotate about the vertical first axis 1 with respect to the vehicle. The swivel base 12 is a supporting structure forming a pivotable interface between the frame base 7 and other components of the seat 100, such as the first squab 22 and the back rest 27. The swivel base 12 is preferably of similar width to the back rest 27 and first squab 22, and is formed of robust material such as steel. An example of a swivel base 12 embodying the invention is shown in Figures 2-4. Each of the frame base 7, first squab 22, and back rest 27 are rotatably coupled to the swivel base 12 at the first, second, and third axes respectively. The swivel base 12 includes a rigid support base 13 which is rotatably coupled with the frame base 7 such that the swivel base 12 can rotate about the vertical first axis 1. Preferably, the support base 13 has an aperture suitable to accommodate a bearing, bush, shaft or the like. In addition, an aperture 14 in the support base 13 is suitable to receive a shaft extending between the support base 13 and the frame base 7. In the example shown, the swivel base 12 is positioned a short distance below the level of the squab. However, in other examples, the frame base 7 is located at or near floor level, and the swivel base 12 is positioned at the lower end of a stem or shaft which supports the seat. The support base 13 has an upper surface 15 and lower face. There may be protrusions and / or indentations on the lower surface 16 of the support base 13 suitable to engage the frame base 7 or vehicle. Preferably the protrusions and / or indentations on the lower surface 16 of the support base 13 are formed concentrically about the first axis 1 of rotation. In the example shown, the swivel base 12 includes are two pairs of opposing base side plates (BSPs): an inner first BSP pair 17 and an outer second BSP pair 18. Each pair has a one BSP on a left side of the swivel base 12 and one BSP on the right side of the swivel base 12. The left and right sides correspond to the left and right sides of an occupant seated with their back against the front face of the back rest 27. The side plates are fixed to the support base 13. Preferably, the side plates are fixed to the upper surface 15 of the support base 13 and project upwardly therefrom. Other support structures are contemplated to which the side plates may be fixed, such as a shaft, beams, bars, sheet metal, or any combination thereof. Preferably the plates comprise opposing holes, which may be lined by bearings. The holes may pass partially or entirely through the side plates. The seat further comprises shafts (described in more detail below) that rotate with the back rest 27 or first squab 22 may extend the full distance or a part of the distance between the opposing holes or indentations in the side plates. The shafts are optionally enclosed to avoid interference from foreign object debris At least one of the BSPs comprises a rotary coupling suitable to form a rotatable coupling between the swivel base 12 and the first squab 22. This may take the form of one or more holes or indentations to receive suitable shafts, bushes, bearings, or the like. Alternatively, a protrusion may be integrally formed with at least one of the first BSPs 17 suitable to be received by a bearing, bush, or the like in the first squab 22. At least one of the BSPs comprises a rotary coupling suitable to form a rotatable coupling with the back rest 27. This may take the form of a hole or indentation to receive suitable shafts, bushes, bearings, or the like. Alternatively, a protrusion may be integrally formed with at least one of the first BSPs 17 suitable to be received by a bearing, bush, or the like in the back rest 27. The first BSP pair 17 are horizontally spaced such that they can engage a pair of first squab side plates (SSPs) 23 on left and right sides of the first squab 22. Preferably, the first BSP pair 17 are horizontally spaced such that their inner (closest) faces are each suitable to engage corresponding outer faces of the SSPs 23. It is also contemplated that the outer faces of the first BSPs 17 could be spaced suitably to engage the inner faces of the SSPs 23. The first BSP pair 17 comprise one or more holes to receive shafts, bearings, or the like to allow the first squab 22 to rotate with respect to the plates about a horizontal axis. A second BSP pair 18 are horizontally spaced such that their inner (closest) faces are each suitable to engage corresponding outer faces of back rest side plates (BRSPs 28). It is also contemplated that the outer faces of the second BSP pair 18 could be spaced suitably to engage the inner faces of the BRSP. The second BSP pair 18 comprise one or more holes to receive shafts, bearings, or the like to allow the back rest 27 to rotate with respect to the plates about a horizontal axis. The swivel base 12 comprises a swivel plunger 19, best seen in figure 1g, formed of a swivel plunger handle (SPH) 20 and a swivel plunger locking pin (SPLP) 21, oriented to engage with the location slots 10 of the frame base 7. The SPLP 21 optionally comprises a flange or another radial projection 42 to restrict the depth that it extends into the radial indexing features 10 of the frame base 7. In the shown example, the swivel plunger 19 is attached to the swivel base 12, with the SPH 20 protruding from the swivel base 12. Preferably the SPH 20 is positioned such that it can easily be grasped and manipulated by a user. In preferred embodiments the swivel plunger 19 may pass through the BSPs or pass above, below, forward, or behind the BSPs. The swivel plunger 19 is biased into the location slots 10 to lock the swivel base 12, and hence the seat itself, into position with respect to the frame base 7. The spring bias must be overcome by the user, by pulling the SPH 20, to disengage the swivel plunger 19. Preferably the spring bias is sufficient to prevent inadvertent contact with the plunger from disengaging the pin 21. The first squab 22 comprises a central padded region which is substantially planar and suitable to support an individual in a seated position facing in the forward direction. The first squab 22 has a squab base to provide rigidity, which may be one or more frames or plates, or a combination thereof. At least an upper surface 15 of the first squab 22 is padded, and may also be upholstered or similar, to provide a comfortable seating surface for the occupant. In the example shown, the squab base comprises a frame 24, best seen in figure 1c, including the two SSPs 23 fixed on left and right sides thereof. Preferably the first SSPs 23 are substantially planar, vertically oriented, and parallel to one another. The SSPs 23 are preferably formed of robust material such as steel. There may be holes provided in both of the first SSPs 23 such that a shaft may pass through both first SSPs 23 perpendicularly. At least one of the first SSP 23 comprises a rotary coupling suitable to form a rotatable coupling with the swivel base 12. This may take the form of a hole or indentation to receive suitable shafts, bushes, bearings, or the like. Alternatively, a protrusion may be integrally formed with at least one of the first SSP 23 suitable to be received by a bearing, bush, or the like in the swivel base 12. At least one of the first SSP 23 comprises a squab slot taking the form of a hole, slot, ledge or depression suitable to receive or interface with a seat plunger 25 when the seat position is in a first position (substantially horizontal). The seat plunger 25 is slidably fixed to the swivel base 12, such that it can translate along its length (substantially perpendicular to the first SSP 23 and BSPs) with respect to the swivel base 12. Preferably the squab slot 24 has rounded edges to help precisely locate the seat plunger 25. The squab slot 24 has a depth to receive at least 20 mm of the length of the seat plunger 25 within. Preferably, the squab slot 24 is sized to receive at least 30 mm or 40 mm of the length of the seat plunger 25. The seat plunger 25 may be a cylindrical shaft or may have another suitable cross-sectional shape such as a square or rectangle. The seat plunger 25 and squab slot 24 may have a non-circular cross-sectional shape, preferably with rotational symmetry, such that the seat plunger 25 must be in a specific orientation to be received by the squab slot 24. Preferably, the seat plunger 25 is biased to rest in the engaged position via a spring or any other appropriate means. At least one of the first SSPs 23 has a second slot taking the form of a hole, slot, or depression suitable to receive the seat plunger 25 when the seat is in a second position (when the first squab 22 is substantially vertical). Preferably, the seat plunger 25 is biased to rest in the engaged position via a spring or any other appropriate means. The spring bias must be overcome by the user to disengage the seat plunger 25. Preferably the spring bias is sufficient to prevent inadvertent contact with the plunger from disengaging the pin. The seat plunger 25 secures the first squab 22 in either one of the first and second configuration positions. This ensures that the first squab remains where intended at all times and able to support load in each position. Retention of the first squab 22 in the second position ensures that the squab does not unintentionally fall back to the first position under load e.g. when being used for support by a standing passenger. Retention of the first squab 22 in the first position ensures that, if a passenger who is sitting in the seat stands up briefly, the first squab remains securely in the first position to receive the passenger when they sit down again. If desired, the first squab 22 can be spring biased into the second position, with this spring biasing taking effect when the first squab 22 is not locked in either position. It would be understood by the skilled person that just one first SSP 23 would also be suitable to work the invention. It is contemplated that the assembly could be reversed such that at least one of the first SSP 23 includes a protrusion to be received by a complimentary plunger when the seat is substantially horizontal, substantially vertical, and any other suitable configuration. The first squab 22 preferably comprises one or more features that prevent the first squab 22 from collapsing below a desired angle, should the seat plunger 25 fail to prevent this. These features may comprise one or more blocks 26 which project from a lower surface 16 of the squab base and abut the swivel base 12 when the first squab 22 reaches a rotation limit, or slightly after the rotation limit is reached, to prevent further rotation. In the first configuration, shown in Figures 1 and 1a-g, the back rest 27 is positioned to support the back of an individual in a seated position and facing in the forward direction. The back rest 27 comprises a padded region which is substantially planar. The padded region may be economically shaped, and slightly concave to provide some lateral support to the passenger. The padded region is fixed to an internal support chassis to provide rigidity, which may be a frame, plate, or a combination thereof. The back rest 27 further comprises including two back rest side plates (BRSP) 28 fixed in relation to the chassis. The BRSP 28 are preferably substantially planar, vertically oriented, and parallel to one another. The BRSP 28 can extend to cover a substantial portion of the sides of the back rest 27. The BRSP 28 are formed of robust material such as steel. There may be holes aligned in both BRSPs 28 such that a shaft may pass through both plates perpendicularly. At least one of the BRSPs 28 comprises a rotary coupling suitable to form a rotatable coupling with the swivel base 12, such that the back rest 27 can pivot about a horizontal axis. This may take the form of a hole or indentation to receive suitable shafts, bushes, bearings, or the like. Alternatively, a protrusion may be integrally formed with at least one of the BRSP 28 suitable to be received by a bearing, bush, or the like in the swivel base 12. Preferably, the rotary coupling is formed at a lower end of the back rest 27. However, alternative locations for rotary couplings are contemplated such as at or around the mid-point along the length of the back rest 27. At least one of the BRSPs 28 comprises a back rest slot taking the form of a hole, slot, or depression suitable to receive a position plunger locking pin (PPLP) 33 when the back rest 27 is in a first configuration (substantially vertical). The PPLP 33 serves to retain the back rest 27 at a fixed inclination with respect to the swivel base 12. Preferably the first slot has rounded edges to help precisely locate the PPLP. The first back rest 27 slot has a depth to receive at least 20 mm of the length of the PPLP 33 within. Preferably, the first back rest 27 slot is sized to receive at least 30 mm or 40 mm of the length of the PPLP. The PPLP 33 may be a cylindrical shaft or may have another suitable cross-sectional shape such as a square. The PPLP 33 and first back rest 27 slot may have a cross-sectional shape with rotational symmetry such that the plunger must be in a specific orientation to be received by the first back rest 27 slot. At least one of the BRSP 28 has a second back rest 27 slot taking the form of a hole, slot, or depression suitable to receive a PPLP 33 when the back rest 27 is in a second configuration. It will be understood by the skilled person that just one BRSP 28 would also be suitable to work the invention. The swivel base 12 also houses a position plunger shaft (PPS) 35, which extends between the second and / or first BSP pairs 18,17, and from one side of the swivel base 12 to the other. The PPS 35 preferably extends through a tube, which also extends substantially across the width of the swivel base 12. The tube may be rigidly fastened to the swivel base 12 and allow the PPS 35 to translate freely therethrough. Preferably there are one or more protrusions or depressions in the PPS 35 to interface with complimentary depression or protrusions in the tube and / or BSPs to limit the distance that the PPS 35 may translate. A position plunger handle 34 is connected to the PPS 35 at a first end of the PPS 35 (in the example shown in the Figure, on the right side of the swivel base 12). The position plunger handle 34 is sized and shaped to be operated easily by a user. Preferably the handle has an outer surface which is flat or substantially flat, and also preferably relatively large, to receive imprecise axial force (such as applied by the foot of a user) and transmit this force to the PPS 35. As best seen in figure 4, a second end of the PPS 35 (left side of the swivel base 12, in the figures), the PPS 35 is connected to the PPLP 33, preferably via a bar 36 secured to, and projecting radially from, the PPS 35. In the embodiment shown, therefore, the PPLP 33 is generally parallel with, but spaced apart from, the PPS 35. The PPLP 33 projects through a hole in one or both of the first and second BSP pairs 17,18 such that it can be received by the first back rest 27 slot, in an engaged position. The PPLP 33 optionally comprises a flange or another radial projection 42 to restrict the depth that it extends into the back rest slot. The PPLP 33 is preferably sized and shaped to be received by the back rest slot to a depth of 20 mm, 30 mm, 40 mm or more in the engaged position. Preferably, the PPLP 33 is biased to engage slots in the back rest 27 when the seat 100 is in the first, second, and third configurations. Optionally, the PPLP 33 is biased to engage further slots in the back rest 27 to allow the back rest 27 to be locked in further positions, as needed. The spring bias must be overcome by the user to disengage the position plunger 32. Preferably the spring bias is sufficient to prevent inadvertent contact with the plunger from disengaging the pin. The skilled person would be aware that the plunger, PPS 35, and plunger handle assembly need not be directly assembled to the second BSPs 18 as described above. An assembly including the first BSPs 17 instead or in combination with the second BSPs 18 would allow the plunger to function as intended. In extending from one side of the swivel base 12 to the other, the position plunger 32 is entirely separated from the locking pin and bar 36 mechanism used to translate the position plunger 32 on the opposing side. It is acknowledged that a spring-biased bar 36 and PPLP 33 may pose an injury risk to the user. This mechanism allows the position plunger 32 to be presented on a side of the seat which projects inwardly into the cabin of the vehicle (in the first configuration), and to be operated by being pushed inwardly (i.e. in a direction towards a centre of the sear) by a user. The locking pin and bar mechanism are positioned on the opposite side of the seat, with the locking pin being retracted from the back rest slot when the position plunger is pushed inwardly in this way. The user’s limbs are therefore also entirely separated from the locking pin 33 and bar 36 when operating the plunger. This reduces the likelihood of foreign objects / debris from affecting the performance of the system as well as any dangerous interaction between the user and the mechanism. Alternatively, the position plunger 32 and locking pin 33 may be on one side of the passenger seat 100 with appropriate additional guarding components to shield the locking pin and user from one another and prevent debris from entering the mechanism. In addition to constraining the rotation of the back rest 27, in the example shown the position plunger 32 also releases the second squab 37 to rotate about the horizontal fourth axis 4. The second squab 37 is pivotably connected to the back rest 27, at a position partway along the height of the back rest 27, and to a first end of a lever 39, where the lever 39 is pivotably connected at a second end to the swivel base 12 at a horizontal fifth axis 5. The second squab 37 comprises a central region which is substantially planar and suitable to support an individual in a seated position facing in the rearward direction. The second squab 37 has a second support base 13 to provide rigidity, which may be a frame, plate, or a combination thereof. At least an upper surface 15 of the support base 13 is padded, and may also be upholstered or similar, to provide a comfortable seating surface for the occupant. The second squab 37 works in conjunction with the second back rest surface 31 to support an occupant facing in the rearward direction, where the occupant is seated with their back against the second back rest surface 31. In the example shown in Figures 1 d-1 f, the second squab 37 comprises a frame including two second SSPs 38 fixed on left and right sides of the central region. Preferably the second SSPs 38 are substantially planar, vertically oriented, and parallel to one another. The second SSPs 38 are preferably formed of robust material such as steel. There may be holes provided in both of the second SSPs 38 such that a shaft may pass through both second SSPs 38 perpendicularly. At least one of the second SSPs 38 comprises a rotary coupling suitable to form a rotatable coupling with the back rest 27. At least one of the second SSPs 38 comprises a rotary coupling suitable to form a rotatable coupling with the lever 39. These may take the form of a hole or indentation to receive suitable shafts, bushes, bearings, or the like. Alternatively, a protrusion may be integrally formed with at least one of the second SSPs 38 suitable to be received by a bearing, bush, or the like in the back rest 27. It would be understood by the skilled person that just one second SSP 38 would also be suitable to work the invention. It is an object of the invention to provide a passenger seat 100 that operates in at least three configurations which correspond to variations in the angular positions of the swivel base 12, first squab 22, back rest 27, and second squab 37 about their respective axes of rotation. An overview of each seat configuration is set out below. It is contemplated that any combination of components and component orientations discussed below could form an additional seat configuration to suit user needs. In the first configuration, the swivel base 12 is fixed at a first angle about the first axis 1, and the passenger seat 100, back rest 27, and first squab 22 are oriented to accommodate a passenger in a seated position and facing in a first direction. In preferred embodiments, when the seat is installed in a vehicle, the first seat back surface 30 faces forward, i.e. in a normal direction of travel of the vehicle. The skilled person will be aware that a squab of a vehicle seat is usually angled to increase in height slightly as it projects forward and away from the back rest 27. The first squab 22 can therefore be inclined and fixed at a range of angles (close to horizontal) in the first configuration. The skilled person would be aware that a back rest 27 of a vehicle seat is usually slightly reclined. The back rest 27 can therefore be inclined and fixed at a range of angles (preferably close to vertical) in the first configuration. In the first configuration, the seat is suitable to receive a forward-facing adult passenger. On the opposing side of the first back rest surface 30 is the second back rest surface 31. In the first configuration, the second squab 37 is rotated about the fourth axis 4 to lie in a stowed position adjacent the second back rest surface 31. This position can be seen most clearly in Figure 3a. Figures 5 and 5a-5e show the passenger seat 100 of Figure 1 in a second configuration, suitable to accommodate an infant passenger facing in a second (backward) direction. In the second configuration, the back rest 27, first squab 22 and second squab 37 are in their second configuration positions as described below. Figure 5 shows the second squab 37 rotatably coupled to the back rest 27 at the fourth horizontal axis. In the second configuration, the swivel base 12 remains fixed at the first angle about the first axis 1. In the second configuration, the first squab 22 is preferably substantially horizontal, and may be locked in this position, as described above. The back rest 27 is angled toward the first squab 22 such that its inclination falls between vertical and horizontal. In the second configuration, the back rest 27 preferably projects in the forward direction. In the second configuration the angle between the first configuration inclination first squab 22 and the back rest 27 is less than 90 degrees, preferably less than 80 degrees, and more preferably less than 75 or 70 degrees. The angle between the first squab 22 it its first configuration position (substantially horizontal), and the back rest 27 is preferably 45-50 degrees, or more preferably 48 degrees. The first squab 22 may fold up to be adjacent the first back rest surface 30. in the second configuration. In the second configuration, the second squab 37 projects rearwardly from the second back rest surface 31 in a deployed position. In the deployed position, the second squab 37 is angled to support a passenger seated facing a second (rearward) direction. The skilled person would be aware that a seat portion of a vehicle seat (second squab 37) is usually angled to increase in height slightly as it projects forward and away from the back rest 27 (second back rest surface 31). The second squab 37 can therefore be inclined and fixed at a range of angles to accommodate a passenger. Preferably, in the deployed position, the second squab 37 is inclined at an angle of around 30 degrees to horizontal and / or the second squab 37 projects substantially perpendicular to the second back rest surface 31. More preferably, the second squab 37 is inclined at an angle of 31 degrees to the horizontal and the second squab 37 projects from the second back rest surface 31 at an angle of 97 degrees. It is an object of the present invention to transition between configurations easily and preferably without the use of tools. Key components of the transition mechanism and the features thereof are set out in more detail below. To transition from the first configuration to the second configuration, the PPLP 33 must first be disengaged from the first back rest 27 slot to allow the back rest 27 to rotate freely, in a forward direction, about the horizontal third axis 3 into its second configuration position. Once the PPLP 33 is disengaged, the back rest 27 may be tilted into its second configuration position. As the back rest 27 is tilted into position, the second squab 37 simultaneously rotates into the deployed position. Figures 1d and 5d shows the back rest side plates 28 and second SSP 38 in the first and second configurations, respectively. A mechanical linkage ensures the second squab 37 rotates into the second configuration position as the back rest 27 moves into its second configuration position, as can be best seen in figures 1c, 1d and 5e. As described in WO03066370A1, the first end of the lever 39 is pivotably joined to the swivel base 12 at a horizontal fifth axis 5 and is pivotably connected at the second end to the second squab 37 at a sixth axis 6 formed through the second SSP 38. The lever 39 is rigid and optionally curved to improve packaging within the seat. Both the fourth and sixth axes are formed through the second SSP 38, with the fourth axis 4 fixed with respect to the back rest 27 and the sixth axis 6 free to rotate with the second SSP 38 about the fourth axis 4. This allows the second squab 37 to rotate with respect to the back rest 27 about the fourth axis 4. The fifth axis 5 is offset from the third axis 3 (around which the back rest 27 rotates) such that when the back rest 27 is tilted, the distance between the back rest 27 and pivotable connection between the lever 39 and swivel base 12 changes. As the distance changes, the sixth axis 6 must move to accommodate the length of the rigid lever 39. This results in rotation of the sixth axis 6 about the fourth axis 4 (around which it is radially constrained). This exerts a moment on the second squab 37 about the fourth axis 4 (applied at the sixth axis 6). Figures 5c and 5d show a radial track 40 around the fourth axis 4, indicating the path that the sixth axis 6 travels. Alternative radial guiding means could also be used to prescribe a motion path for the sixth axis 6 such as a groove, or curved protrusion. The radial guiding means may be on one or both of the left and right sides of the passenger seat 100. Figure 1c also shows a horizontal beam 43 between the left and right sides of the back rest side plates 28 to provide reinforcement and stiffness for the back rest 27. Preferably there is a corresponding notch in the lever 39 or the trajectory of the lever 39 is such that clearance is maintained between the lever 39 and the horizontal beam during transition between configurations. Preferably the offset direction of the fifth and sixth axes from the third and fourth axes respectively are the same (e.g. both fifth and sixth axes are forward of / backward of / above / below the third and fourth axes respectively). Optionally, the lever 39 has a protrusion at its first end to abut the swivel base 12 in the first configuration and / or the second configuration to prevent rotation of the lever 39 beyond a desired limit. This provides further security to the seat positioning, adding redundancy. At the second end, the lever 39 is preferably shaped to allow the second squab side plates 38 to rest directly on the lever 39 when locked in the second configuration position (where the second squab 37 is deployed). This provides additional security to the seat positioning, adding redundancy. By the above-described mechanism, the second squab 37 can be moved to the deployed position or to the stowed position adjacent the second back rest surface 31 by rotation of the back rest 27 alone. The rigid connection between the back rest 27 and second squab 37 via the lever 39 means the stowage / deployment of the second squab 37 is also controlled and fixed by the position plunger 32. This reduces the complexity and demand on the user when altering the configuration of the passenger seat 100. Figure 3 shows the passenger seat 100 of Figure 1 in a third configuration, suitable for compact storage. In the second configuration, the back rest 27, first squab 22 and second squab 37 are in their third configuration positions as described below The back rest 27 is substantially vertical and both the first squab 22 and second squab 37 are oriented such that they are folded adjacent the back rest 27 against the first back rest surface 30 and the second back rest surface 31 respectively. The first and second squabs 22, 37 are oriented substantially vertically or as close to vertical as the assembly allows. In the third configuration, the swivel base 12 is fixed at a second angle about the first axis 1. Preferably, the second angle is orthogonal to the first angle however alternative angular offsets are considered such as 40, 45, 50, 60, or 80 degrees. To position the swivel base 12 into its third configuration position from the first position, the swivel plunger 19 must be retracted such that the SPLP 21 does not engage the location slots 10, allowing the swivel base 12 to rotate about the first axis 1 until the swivel plunger 19 is aligned with the appropriate location slot. The swivel plunger 19 is then biased into the location slot to lock the swivel base 12, and hence the seat itself, into the third configuration. The first squab 22 is then placed in its second position, by operation of the seat plunger 25 as described above. The passenger seat 100 is suitable to be stored against a side wall of a vehicle in the third configuration in an unobtrusive manner. For embodiments optimised for storage against a side wall of a vehicle, the first axis 1 is positioned proximal the left or right side of the passenger seat 100. It is contemplated that the first squab 22, back rest 27, and second squab 37 could be configured in any manner as discussed above with the swivel base 12 at any suitable angle about the first axis 1. In light of this disclosure as a whole, the skilled person would appreciate that the angle of the swivel base 12 can be varied independently of the angles of the first squab 22, back rest 27 and second squab 37 in relation to the swivel base 12. Each of the aforementioned passenger seat 100 configurations provides a set of advantages to the user. In the first configuration, the seat is faces in a forward direction and provides forward-facing seating for an adult passenger. The first squab 22 and back rest 27 are securely fixed in place to comfortably support the passenger. Each of the plungers is accessible to the passenger from the seated position but situated such that they are unlikely to be inadvertently contacted by the occupant or passer-by. This is of particular relevance in utility vehicles like ambulances where movement within the vehicle could lead to inadvertent contact with the seat and plungers. In the second configuration, the seat remains in the same orientation on the frame base 7 with the back rest 27 folded forward and the second seat deployed to receive a passenger in a rearward-facing position. Without the addition of further supplementary seating components (such as child car seats), and without increasing the overall footprint of the passenger seat 100, rearward facing seating is provided. The second squab 37 is deployed by disengaging the position plunger 32 and applying force on the back rest 27 in a forward direction. The greater length of the back rest 27 compared to the second squab 37 allows a greater moment to be applied by the user without having to exert excessive force. In addition, the back rest 27 is more accessible (more easily reached) than the second squab 37 and therefore applying force to the back rest 27 to transition to the second configuration is advantageous. The back rest 27 is closer to the shoulder height of the user, which makes the application offeree more comfortable when tilting the back rest 27 to deploy the second squab 37. Optionally, there is handle or additional padded region on the upper portion of the back rest 27 to help the user comfortably apply a tilting force. The deployment of the second squab 37 simultaneously with the forward tilt of the back rest 27 reduces the complexity of the transition process. There is no requirement to separately deploy the second squab 37 once the back rest 27 is in the second configuration position. It is an object of the invention to provide a passenger seat 100 where a user can transform the seat to accommodate a rearward facing passenger without using their hands. Accordingly, the position plunger 32 is large enough to be operated by a user’s foot or knee, and the back rest 27 act to transmit the tilting force. The length, padding, and relatively larger surface area of the back rest 27 compared to the second squab 37 allows the user to exert a tilting force to the back rest 27 using their shoulder, elbow, knee or any other suitable body part. The design of the transition mechanism from the first configuration to the second configuration as outlined above is particularly advantageous in utility vehicles such as ambulances. It is contemplated that a user may not have full use of their hands or may be carrying additional items when operating the seat in this setting. For example, a user may be holding a child to be seated on the second squab 37 when transitioning the seat from the first to the second configurations and therefore operating the seat without use of their hands is advantageous. Preferably the first seat squab remains in its first configuration position (substantially horizontal) when the passenger seat 100 is in the second configuration to avoid interference between the first seat squab and the back rest 27. In the third configuration, the seat is orientated orthogonally on the frame base 7 with respect to the first and second configurations. The first seat squab is oriented vertically and adjacent the back rest 27 by disengaging the seat plunger 25 and lifting the squab. The second seat squab is oriented vertically and adjacent the back rest 27 by disengaging the position plunger 32 and returning the back rest 27 to the vertical (first configuration) position. The seat may be swivelled in either direction into the orthogonal orientation such that either the first or the second squab 37 can lay adjacent a vehicle wall. In this configuration the seat is in its most compact form allowing for efficient storage, preferably against a wall of a vehicle. In the vehicle context, this allows for greater utility of the vehicle, making it suitable both to carry passengers in the seats in their first and second configurations and store large items when the seats are in their third configuration. This is of particular relevance in an ambulance as they can be required to carry a stretcher, adult (forward facing) passengers, and / or infants (rearward facing passengers) simultaneously or consecutively. Orientating the seats into the third configuration vacates a large central region in the vehicle suitable to accommodate a stretcher or other large equipment pieces. Being able to quickly and easily alter the configuration of the seats installed in the vehicle allows a single vehicle to be used to for all of the aforementioned occupants without a length (and expensive) overhaul of the vehicle layout and internal furnishings. A fourth seat configuration is contemplated which is the same as the third configuration save for the first seat squab being substantially horizontal. In this configuration, a passenger may be received with their back against the back rest 27 and facing orthogonal to the forward direction. In the fourth configuration, it is envisaged that a seated passenger may be accommodated in a seated position while sufficient space is maintained in a central region of the vehicle to receive large cargo such as a stretcher. The skilled person would appreciate that a passenger seat 100, having a plurality of seating configurations as disclosed herein would provide significant benefit to the user providing enhanced safety and adaptability. The skilled reader will appreciate that the use of the terms “horizontal” and “vertical” above refer to the orientation of a seat as it is conventionally installed in a vehicle (i.e. where the vertical plane extends from the floor to ceiling and the horizontal plane is approximately parallel with the vehicle floor / ground). In the examples above, the seat 100 pivots about a first axis 1 which is located on one side of the frame base 7, but is otherwise fixed with respect to the vehicle floor. However, this need not be the case. In embodiments the frame base 7 may be arranged so that it can slide with respect to the vehicle along a translation path. The frame base 7 may be selectively lockable with respect to the vehicle at a plurality of locations along the path. In some embodiments, the frame base 7 may interface with one or more body rails which are fixable to a vehicle. The rails may be directly welded to the vehicle or comprise holes or fixtures to interface with the vehicle. The body rails allow the frame base 7 and thus the entire passenger seat 100 to translate with respect to the vehicle. This also allows the first axis 1 to translate with respect to the body rails, so that the frame base 7 can both slide and rotate with respect to the vehicle. Translation of the passenger seat allows an occupant to move within the vehicle without removing their seatbelt, improving occupant safety. In such embodiments the frame base 7 may comprise a one or more seat rails to slidably interface with the body rails. Alternatively, the frame base 7 may comprise one or more alternative sliding elements such as wheels or carriages, configured to slidably interface with and / or be retained by the body rails. Any other suitable cooperating components that allow the frame base 7 to slide may also be used. The body rails (and any corresponding seat rails) may be oriented at any angle with respect to the direction of travel of the vehicle and passenger seat. In some embodiments the body rails may be fixed directly to the vehicle floor, to a cantilever protruding from a vehicle wall, or to a pedestal protruding from the floor of a vehicle. The body rails (and any corresponding seat rails) may be oriented parallel with the forward / backward direction of the vehicle. The body rails (and any corresponding seat rails) may alternatively be oriented perpendicular to the forward / backward direction of the vehicle. Preferably the rails are straight and horizontal to facilitate the translation of the passenger seat along a straight horizontal trajectory into a desired position. Optionally, the rails are curved in the horizontal and / or vertical direction to translate the passenger seat along a curved trajectory into a desired position. This allows obstacles to be avoided when translating the passenger seat. In an alternative configuration, the swivel base is not mounted to the frame base 7 and is instead mounted directly and slidably to the body rails. The body rails are rotatably coupled to the vehicle such that they may rotate about a vertical axis, (alternative first axis but goes against claim 1). As discussed above, the passenger seat 100 has a configuration in which an infant or child is supported by the second squab 37. Particularly for a larger child, or where a parent or caregiver requires additional space, the ability of the seat 100 to slide laterally will be of particular utility in configuring the space around the seat 100. This aspect will also find application in utility vehicles such as ambulances, where a caregiver may, for example, be seated in the seat 100 while attending to a patient lying on a stretcher within the ambulance. The ability of the seat 100 to slide allows the caregiver to be positioned at a desired placed alongside the stretcher, to assist the patient while remaining secured to the seat 100. As described above, the swivel base 12 includes the rigid support base 13 which is rotatably coupled with the frame base 7 such that the swivel base 12 can rotate about the vertical first axis 1. The rotatable coupling between the rigid support base 13 and the frame base 7 defines the first axis of rotation 1. In the example shown in the figures, the first axis 1 is positioned close to one side of the seat 100, which allows the seat 100 to move between the first or second configuration and the third configuration, in which the seat 100 can be stowed against a wall of the vehicle. In other examples, the first axis 1 is positioned within a projected area of the passenger seat 100 (i.e. a vertically projected area, such that the first axis is within the “footprint” of the seat 100). More specifically, the first axis 1 is positioned within a projected area of the first squab 22 in the deployed configuration. The first axis 1 may also (or alternatively) be positioned within a projected area of the back rest 27. Optionally, the first axis 1 of rotation may be positioned anywhere between the second BSP pair 18. Preferably the first axis 1 of rotation is equidistant or substantially equidistant between the left and right sides of the swivel base 12. Preferably the first axis 1 of rotation is equidistant or substantially equidistant between the inner first BSP pairs 17. Preferably the first axis 1 of rotation is equidistant or substantially equidistant between the outer second BSP pairs 18. Preferably the first axis of rotation 1 is between left and right sides of the first squab 22. More preferably the first axis of rotation 1 is equidistant or substantially equidistant between left and right sides of the first squab 22 Preferably the first axis 1 of rotation is no further forward than the forward most portion of the first squab 22 in the deployed position. Preferably the first axis 1 of rotation is no further backward than the backward most portion of the second squab 37 in the deployed position. Alternatively, the first axis of rotation is outside of (not between) left and right sides of the first squab 22. Further alternatively, the first axis of rotation 1 is outside the projected area of the passenger seat 100. In precisely positioning the first axis 1, the passenger seat 100 can rotate without interfering with adjacent structures. Positioning the first axis 1 equidistant between first and second sides of the passenger seat 100 minimises the swept area of the passenger seat 100 during rotation which in turn minimises the floor space required for each seat 100. This is particularly relevant for when the seat is installed in emergency vehicles where space is very limited. A paramedic or carer's seat in an ambulance is often positioned between two or more adjacent structures such as storage units. The centrally positioned first axis allows the seat to be rotated within the confines of the adjacent structures. Rotating the seat allows the seat to remain versatile and accommodate an adult or child on respective first and second squabs 22, 37 despite the confined space. In some embodiments the centrally positioned first axis 1 is used in combination with variations of the passenger seat where the frame base 7 may slide with respect to the vehicle. This allows the seat occupant to manoeuvre the seat around adjacent structures for example to reach a patient for treatment. This is particularly advantageous as allowing an occupant to rotate and / or translate within a vehicle without removing restrains such as seat belts. This improves occupant safety. Preferably the swivel base 12 may rotate at least 180° or more preferably 360° with respect to the frame base 7 about the first axisl. This allows the seat to accommodate a passenger seated on either the deployed first squab 22 or deployed second squab 37 facing in any direction about the first axis 1. In particular, in a utility vehicle such as an ambulance, it may be preferred for an occupant of the seat 100, whether the occupant is an adult ora child, to face in a rearward direction. The skilled reader will appreciate that the seat assemblies described above will be relatively straightforward to construct and will perform robustly and reliably in all described configurations to protect occupants in the event of a crash. When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components. The invention may also broadly consist in the parts, elements, steps, examples and / or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and / or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein. 5 Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure. Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be 10 construed literally, purposively, and / or to encompass equivalents.

Claims

1. A passenger seat comprising:a frame base suitable to be coupled to a part of a vehicle such that the frame base is fixed in place with respect to the part of the vehicle;a swivel base, rotatably coupled to the frame base such that it can rotate with respect to the frame base about a first axis;a first squab, rotatably coupled to the swivel base such that it can rotate with respect to the swivel base about a second axis, between a stowed configuration and a deployed configuration;a back rest, rotatably coupled to the swivel base such that it can rotate with respect to the swivel base about a third axis, which is substantially parallel with the second axis;a second squab, rotatably coupled to the back rest such that it can rotate with respect to the back rest about a fourth axis, between a stowed configuration and a deployed configuration.

2. The passenger seat of claim 1, wherein the back rest can rotate between at least two angles of inclination corresponding to a first configuration position and a second configuration position.

3. The passenger seat of claim 2, wherein when the back rest rotates from the first configuration position to the second configuration position, the second squab rotates from the stowed position to the deployed position.

4. The passenger seat of claim 3, wherein a second squab is pivotably connected to a first end of a lever at a sixth axis, and the lever is pivotably connected at a second end to the swivel base at a fifth axis.

5. The passenger seat of claim 4, wherein the fifth axis is parallel with and offset from the third axis.

6. The passenger seat of any one of claims 2 to 5, wherein the back rest can rotate into a third angle of inclination for storage.

7. The passenger seat of claim 4 or any claim dependent thereon, wherein the back rest comprises a radial track, centred about the fourth axis in which the sixth axis travels when the back rest is rotated between the angles of inclination.

8. The passenger seat of claim 2 or any claim dependent thereon, further comprising a back rest locking mechanism, to lock the back rest in either of the two angles of inclination.

9. The passenger seat of claim 8 wherein the back rest locking mechanism includes a locking pin which can be selectively received in respective apertures, corresponding to angles of inclination of the back rest.

10. The passenger seat of claim 9, further comprising a release mechanism, which can be operated by a user to withdraw the locking pin from any of the apertures, and wherein the release mechanism comprises a control which projects outwardly from a part of the seat, and which is pressed inwardly in order to withdraw the locking pin from the apertures.

11. The passenger seat of claim 10, wherein the control is positioned on a first side of the seat, and the locking pin is positioned on a second, opposite side of the seat.

12. The passenger seat of any previous claims 9 to 11, wherein the locking pin is a spring-loaded pin, biased to be received in the apertures.

13. The passenger seat of any previous claim wherein, in the stowed configuration the first squab is substantially vertical, and in the deployed configuration the first squab is substantially horizontal.

14. The passenger seat of any previous claim wherein the first squab can be locked in position in the stowed configuration and in the deployed configuration.

15. The passenger seat of any previous claim wherein the back rest must pass through a substantially vertical orientation to rotate from the first configuration position to the second configuration position.

16. The passenger seat of any previous claim further comprising a swivel plunger secured to the swivel base, the swivel plunger being selectively received by the frame base to fix the two components with respect to one another.

17. The passenger seat of any of claims 1-16 further comprising a swivel plunger secured to the frame base, the swivel plunger being selectively received by the swivel base to fix the two components with respect to one another.

18. The passenger seat of claim 16 where the swivel plunger is spring-loaded, biased to be received by the frame base.

19. The passenger seat of claim 17 where the swivel plunger is spring-loaded, biased to be received by the swivel base.

20. The passenger seat of any previous claim where the frame base further comprises concentric slots or grooves suitable to receive a projection from the swivel base.

21. The passenger seat of claim 20 wherein the concentric slots are of a constrained length such that, when they receive the projection from the swivel base they restrict rotation of the swivel base with respect to the frame base.

22. The passenger seat of claim 10 wherein the control and the locking pin are connected by a shaft, the shaft being enclosed by, and rotatable with respect to, a tube.

23. The passenger seat of claim 4 or any claim dependent thereon, wherein the lever is shaped to allow the second squab to rest directly on the lever when the second squab is in the deployed position.

24. A vehicle having a passenger seat according to any preceding claim installed therein, wherein the passenger seat is fixed in place with respect to a part of the vehicle.

25. A vehicle according claim 24, wherein the passenger seat, wherein the passenger seat is attached to an internal wall of the vehicle, or fixed in place with respect to an internal wall of the vehicle, such that in one configuration of the passenger seat, a forward surface of the back rest faces in a direction which is generally perpendicular to the internal wall, and in another configuration of the passenger seat, the forward surface of the back rest faces in a direction which is generally parallel with the internal wall.A

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