GB2337925A - Folding mechanism for a seat - Google Patents

Abstract

A vehicle seating unit comprises a base module 5, a cushion support frame 2 and a squab support frame 3 which are mounted on a common axis of rotation 11. A coaxial folding mechanism controls the angles between the cushion support frame and the base module and between the squab support frame and the base module. Both the cushion support frame and squab support frame can be folded together to lie substantially parallel to one another in both near-horizontal and near-vertical planes as well as being foldable to a plurality of normal seating and reclining positions. A head restraint is adapted to assume variable angles with respect to the axis of the squab support frame, dependent upon the angle of the squab frame with respect to the cushion support frame.

Description

2337925 FOLDING MECHANISM FOR A SEAT The present invention relates to

folding seats, and in particular, seats which offer versatile folding and deployment arrangements for use in vehicles.

There is a wide variety of folding seat designs in the prior art, especially in connection with vehicle seating. However, customer demand has led to ever more versatile arrangements for seating units in vehicles which can be deployed in a number of places, removed, and even folded differently according to use.

It is an object of the present invention to provide a versatile seating unit which can readily be deployed in a number of positions in the vehicle, in a number of configurations corresponding to both folded and unfolded conditions.

It is a further object of the present invention to provide a versatile seating umit which has a simple, compact, easy to use, and robust folding mechanism.

According to one aspect, the present invention provides a vehicle seating umt comprismig a base module, a cushion support frame and a squab support frame mounted on a common axis of rotation, and a coaxial folding mechanism for controlling the angles between the cushion support frame and the base module, and between the squab support frame and the base module.

1 According to a further aspect, the present invention provides a vehicle seating unit comprising a base module, a cushion support frame and a squab support frame, said squab support frame having an adjustable angle relative to at least one of said base module or said cushion support frame, the seating unit further including a head restraint frame pivotably coupled to said squab support frame, the head restraint support frame bewig adapted to assume variable angles according to the relative angle between the squab support frame and the base module or cushion support frame.

Embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a side view of a seating unit frame (without upholstery) according to one embodiment of the present invention, in a 15 normal deployed condition; Figure 2 shows a side view of the seating unit of figure 1, in a reclined condition; Figure 3 shows a side view of the seating unit of figure 1, in a vertical folded condition; 20 Figure 4 shows a side view of the seating unit of figure 1, in a horizontal folded condition; Figure 5 shows a perspective view of a coaxial folding mechanism used in the seating unit of figure 1; Figure 6 shows a perspective view of the folding mechanism of 25 figure 6, but with partial cut away section to reveal internal detail; Figure 7 shows: (a) an inside perspective view of a squab support disc of the seating unit of figure 1; (b) a corresponding external perspective view; and (c) a partial cross-sectional view showing internal slot profile; 2 Figure 8 shows an internal side view of the squab support disc of figure 7; Figure 9 shows: (a) an inside perspective view of a cushion support disc of the seating unit of figure 1; (b) a corresponding external perspective view; and (c) a partial cross-sectional view showing internal slot profile; Figure 10 shows an internal side view of the cushion support disc of figure 9; Figure 11 shows a detailed perspective view of a head restraint 10 support frame for the seating unit of figure 1; Figures 12 to 15 show side views of the seating unit of figure 1, with detail of the head restraint support frame actuator mechanism, in which Figure 12 corresponds to the normal deployed condition; Figure 13 corresponds to the reclined position; Figure 14 corresponds to the vertical folded condition; and Figure 15 corresponds to the horizontal folded condition.

Throughout the present specification, it will be understood that references to "vertical" and "horizontal" planes refer to orientations arising from conventional installation of the seating unit on the floor of a vehicle.

With reference to figures 1 to 4 there is shown a schematic side view of a seating unit 1 according to a presently preferred embodiment of the present invention. The seating unit 1 comprises the major components of cushion support frame 2, squab support frame 3, folding head restraint support frame 4, and base module 5.

3 Base module 5 is adapted to plug into a track-based floor mounting system such as that described in co-pending UK patent application no.

entitled "Track-based seating for a vehicle", and provides the longitudinal adjustment mechanism for positioning the seating unit within a vehicle, although in the context of the present invention, other base modules for connecting the seating unit to the floor of a vehicle could be used.

The cushion support frame 2 (hereinafter "cushion"), squab support frame 3 (hereinafter "squab") and head restraint support frame 4 (hereinafter "head restraint") are all shown without upholstery, which can be attached to the various frames using any convenient known techniques. The frames may be of any type suitable for bearing the required seating loads, which may include integral seat belt loadings, which types may include moulded reinforced plastics constructions or conventional metal frames.

The seating unit 1 is shown in figure 1 in what is described herein as the normal deployed condition. The seating unit 1 is shown in figure 2 in what is described herein as the reclined condition. The seating unit 1 is shown in figure 3 in what is described herein as the vertical folded condition. The seating unit 1 is shown in figure 4 in what is described herein as the horizontal folded condition.

In the horizontal and vertical folded conditions, the cushion and squab assume positions substantially parallel to one another (taking into account limitations due to the depths of upholstery), and each occupy near-horizontal or near-vertical planes, which expressions are intended 4 to include the slight drop position of cushion as illustrated in figure 4, to be discussed later.

To achieve a particularly compact horizontal and vertical fold condition, it may be desirable to provide appropriate upholstery on the cushion and squab which is compressible or collapsible. For example, upholstery could be used which includes an air filled foam padding which, upon opening a suitable valve is permitted to collapse to a reduced thickness when the seating is folded. Such foam-based materials are known in the art.

There may be other positions of squab 3 intermediate or beyond the positions shown in figures 1 and 2. Similarly, there may be other positions of cushion 4 intermediate or beyond the positions shown in figures 3 and 4.

The horizontal folded condition (figure 4) is particularly adapted for use when the seating unit 1 is provided as a rear seat in a vehicle, ie. immediately forward of a luggage bay. The horizontal fold provides for extending a load bay floor positioned behind the seating unit, particularly where the existing load bay floor is somewhat higher than the floor on which the seat is mounted.

In this respect, the base module 5 may also be adapted to provide for a combined lowering of the squab and cushion when the seating unit is placed into the horizontal folded condition, using an appropriate mechanism such as that described in co-pending UK.patent application no. entitled "Track-based seating for a vehic le".

The vertical folded condition (figure 3) is particularly adapted for use when the seating unit 1 is provided as a rear seat in a vehicle, ie. immediately behind the front seats, although use in other parts of the vehicle is not precluded, eg. as a forward passenger seat. The vertical fold provides for compact stowage of the seating unit in any suitable position, such as immediately behind a forward seat. This is particularly so when the seating unit is combined with a sliding mechanism to allow the folded seating unit 1 to be moved to a position immediately behind the forward seat. Alternatively, the vertical fold allows for creation of a larger stowage area immediately in front of the seat, better utilising the foot well.

In both the vertical and horizontal folded conditions, preferably the head restraint 4 is adapted to fold to an angle at which it is no longer substantially co-planar with the squab 3, as shown in the figures. A suitable head restraint and actuator mechanism is described later.

In the preferred embodiment as shown in figures 1 to 4, the cushion and squab are mounted on the base module using a coaxial fold mechanism 10 forming part of the seat adjustment mechanism, as shown in figure 5. Thus, the squab and the cushion both pivot about a common axis 11, embodied as a shaft 12 which may extend across the full width of the seating unit 1 to a corresponding coaxial fold mechanism on the other side of the seating unit. Alternatively, independent mechanisms may be used on either side of the seating unit.

Throughout the present specification, the coaxial fold mechanism pertaining only to the left hand side of the seating unit will be described. It will be understood that a corresponding mechanism may be provided 6 on the right hand side of the seating unit, with or without the mechanism on the left hand side of the seating unit. The opposite side to the coaxial fold mechanism 10 may be a simple pivot, coaxially aligned with shaft 12. Where a coaxial fold mechanism 10 is provided on both sides of the seating unit 1, suitable link devices may be provided to ensure simultaneous action, to be described hereinafter.

For clarity, because of the interchangeability of the mechanism for left and right sides, the "inside" face of components to be described refers to the side facing the seat squab and cushion, while the "outside" face refers to the side facing outwards from the side of the seating unit.

With reference to figures 5 and 6, the coaxial fold mechanism 10 comprises a support bracket 15 which is used to couple the fold mechanism to the vehicle floor, preferably via other parts of a base module 5 which provides for seat position adjustment within the vehicle and/or removal from the vehicle, and preferably also provides for seat height adjustment.

The support bracket 15 provides support for the shaft 12, on which a cushion support disc 16 and squab support disc 17 are coaxially, rotatably mounted.

The cushion support disc 16 includes a stub 20 which forms the male part of a plug and socket arrangement for connecting the main part of the cushion support frame 3 to the coaxial fold mechanism 10. A corresponding female portion is provided on the main part of the cushion support frame (not shown).

7 The squab support disc 17 includes a stub 30 which forms the male part of a similar plug and socket arrangement for connecting the main part of the squab support frame 3 to the coaxial fold mechanism 10. A corresponding female portion is provided on the main part of the squab support frame (also not shown).

Other connection arrangements may be used between the discs 16, 17 and the main parts of the cushion and squab support frames, or they may be of unitary construction.

Each support disc 16, 17 is of varying radius and includes an abutment portion which extends out of plane with the main portion of the disc to co-operate with the other disc.

The squab support disc 17 is generally of a larger radius than the cushion support disc although it may have a segment removed as best shown in figure 7. The abutment portion 34, which also serves as a base for the stub 30, extends out of plane of the disc 17 on the outside face 33. The disc 17 includes an arcuate slot or groove 35, of radius r which preferably subtends an angle of approximately 155' about the axis 11.

The angle subtended by the squab support disc slot 35 defines the maximum variation permitted in the movement of the squab 3 and may be varied according to requirements.

For reasons which will become clear, the arcuate slot 35 need not extend all the way through the thickness of the disc 17, and in the preferred embodiment, does not do so, ie. it forms a groove on the inside surface 8 32 of the disc 17. The expression "sloC used hereinafter encompasses both variants.

In the case of the cushion support disc 16, a reduced radius portion 21 extends over a sector of approximately 250' and an increased radius portion 22 extends over the remaining sector of approximately 110'. The increased radius portion 22 includes an arcuate slot 23, also of radius r which subtends an angle of approximately 90' in the increased radius portion 22. At the stub 20, the radius of the cushion support disc 16 is greater than the main radius of the squab support disc. The abutment portion 24 of disc 16, which also serves as a base for the stub 20, extends out of plane of the disc 16 on the inside face 25.

The angle subtended by the cushion support disc slot 23 defines the 15 maximum variation permitted in the movement of the cushion 2 and may be varied according to requirements.

Referring again to figure 5, the two discs 16, 17 are coupled together on the common axis 11 such that the outside surface 33 of the squab support disc provides an external surface of the mechanism 10, the inside surface 32 facing the outside surface 26 of the cushion support disc 16. The inside surface 25 of the disc 16 faces the squab 3 and cushion 2.

The inner circumferential surface 27 of the abutment portion 24 of the cushion support disc 16 is in sliding engagement with the outer circumferential surface 36 of the squab support disc 17.

The inner arcuate surface 37 of the abutment portion 34 is in sliding engagement with the outer circumferential surface 28 of the reduced 9 radius portion 21 of the cushion support disc 16. Upon relative rotation of the two discs 16, 17, the abutment portion 34 collides with the increased radius portion 22 of the cushion support disc 16 thereby limiting further relative movement thereof. This provides an additional 5 bearing surface for weight placed on the squab.

The profile of the slots 23, 35 will now be described in detail.

In the squab support disc 17, the slot 35 profile is as shown in cross section in figure 7c. In summary, the slot 35 has a large, rebated width w, (in the disc radial direction) which is reduced at first and second shoulders 40, 41 to a small width w, at selected depths in the slot. The first shoulder 40 has a depth d, and is separated from the second shoulder 41, of depth d2, by a rebate portion of depth d3. The depth of the first rebate, ie. the depth of the shoulder 40 from the inside surface 32 of the disc 17 is d4.

In the cushion support disc 16, the slot 23 profile is as shown in crosssection in figure 9c. In summary, the slot 23 has a large width w, (also 20 in the disc radial direction) which is reduced to w, at a single shoulder (hereinafter the "third shoulder") 42 of depth d5 at a distance d6 below the inside surface 25 of the disc 16.

With particular reference to figures 8 and 10, each shoulder 40, 41, 42 is provided with cut-out segments locally increasing the width w, to w, at strategic positions along the arc, which segments act as locking points and escapements for a travelling pin to be described hereinafter.

Manufacture of the discs 16, 17 can be conveniently effected by forming each disc from a succession of overlaid thinner discs (of appropriate thicknesses d, to d6, each having a slot of requisite width, rather than forming rebates in a single disc.

Referring again to figures 5 and 6, a travelling pin 18 passes through or into the slots 23, 35 and engages with the discs 16, 17. The travelling pin 18 comprises a shaft having at least four sections 45, 46, 47, 48.

A first section 45 is defined by a shoulder having a diameter approximately equal to or slightly less than wl (ie. corresponding to the rebated portions of the slots 23, 35) and an axial length approximately equal to the depth d2 of the second shoulder 41. The second section 46 has a diameter approximately equal to or slightly less than wS (ie.

corresponding to the shouldered portions of the slots 23, 35) and an axial length approximately equal to the total depth d3+dl+d4. The third section 47 is defined by a further shoulder having a diameter approximately equal to or slightly less than w, and an axial length approximately equal to a half of d5. The fourth section 48 has a diameter approximately equal to or slightly less than wS and an axial length approximately equal to one half d5 + d6.

In the preferred embodiment, dl=d2=d3, d4 is slightly less than dj, and d5=d6=2dj.

In a preferred embodiment, in cushion support disc 16, cut out segments 55 are provided in the third shoulder 42 at 0', 16' and 90' positions starting from a reference end 56 in which the cushion is in a lower 11 stowed position corresponding to the seating unit horizontal fold condition of figure 4.

In a preferred embodiment, in squab support disc 17, cut out segments 57 are provided in the first and second shoulders 40, 41 at 0', 50' and 156' positions starting from a reference end 58 corresponding to the seating unit horizontal fold condition of figure 4.

It will be understood that the number and positions of these shoulders / rebates are a matter of choice for particular requirements of the seating deployment plan and can be varied as required for any particular arrangement.

The travelling pin 18 also includes a fifth section 49 which slides axially within a guide chamber 19. The distal end 50 of the travelling pin 18 is connected to a suitable link 51 for connection to an actuator (not shown) which is operable by a user of the seating unit.

In use, the user of the seat is able to displace the travelling pin along its longitudinal axis to engage the first and third sections into segments 55, 57 as desired to reconfigure the seat between various conditions as exemplified in figures 1 to 4.

In the preferred embodiment, the travelling pin 18 has four axial 25 positions, corresponding to successive leftward (inward) displacements of distance d, from the home position shown in figure 6.

In the first (home) position, both cushion 2 and squab 3 are locked in a selected position; in the second position, the cushion is locked in a 12 selected position and the squab is free to move between selected positions; in the third position, the squab again becomes locked in a selected position and the cushion is free to move and in the fourth position, both the cushion and the squab are free to move.

It will be understood that transition between locked and unlocked positions can only take place at selected positions as the cut out segments 55, 57 provide escapements for the travelling pin to pass through the shoulders between rebated portions of die slots.

A suitable actuation mechanism may be provided with two operating levers to independently control movement of the travelling pin to an appropriate position for cushion movement or squab movement, with dual operation of the levers for movement of the travelling pin to the appropriate position for joint cushion and squab movement.

The cushion support disc 16 and the squab support disc may be separated from one another on-axis by a sufficient distance to allow actuation of the travelling pin from an intermediate longitudinal position thereof. In this case, slot access is only required on the inside face of the squab support disc and on the outside face of the cushion support disc. In this arrangement, the travelling pin could be formed in two halves, suitably linked.

With reference now to figures 11 to 15, a suitable actuator mechanism for the head restraint 4 will now be described.

With particular reference to figure 11, the head restraint 4 comprises a frame 60 for mounting upholstery thereon. The frame is pivotally 13 coupled by pivot bar 61 to a support bracket 62, which may be secured to the top edge of the squab support frame 3 (figure 1). At each end of the pivot bar is an actuating cam 63 which provides an actuator cable attachment point 64. The actuator cam 63 includes a lug 65 adapted to collide with a shoulder 66 on the support bracket to restrict the extent of rotation of the pivot bar 61 at the extreme ranges of movement of the head restraint.

Although a corresponding actuating cam 63, cable attachment point 64, lug 65 and shoulder 66 are preferably provided on both sides of the head restraint, it will be understood that provision on only one side, or in an intermediate position along the pivot bar 61 is also possible.

The head restraint frame 60 is preferably biassed to the position shown m figures 11 and 12, ie. in-line with the seat squab 3.

With reference to figure 12, a flexible control cable 70 runs the height of the squab, within the squab support frame 3 and acts as a head restraint actuator. One end 71 of the actuator cable 70 is connected to the attachment point 64 of the cam 63. The other end 72 of the actuator cable 70 is connected to a cushion lug 75 which is attached to or in fixed relation to the cushion support frame 2. The actuator cable 70 is guided within the squab frame or could run through a control cable sheath 74 affixed to the squab frame 4.

The actuator cable 70 preferably includes a spring link 73 in the cable length to allow a slight extension in the actuator cable 70 under conditions of sufficient load.

14 The actuator cable could be replaced with any suitable mechanical linkage which effectively links the cushion support frame 2 with the head restraint support frame 4, through the squab support frame 3. The spring link 73 could be replaced by any suitable mechanism for allowing an increase in the effective length of the actuator cable 70 or link between the cushion support frame 4 and the head restraint support frame 4.

With the seating unit 1 in the normal deployed position of figure 12, the 10 head restraint is held in the in-line position by the spring bias of the head restraint frame 60 as discussed above. During deployment of the seating unit 1 by approximately 50' to the reclined condition of figure 13, a slight increase in the distance between the cushion lug 75 and the squab frame cable guides causes the actuator cable 70 to draw the head restraint forward slightly to the position shown in figure 13. This provides an improved sleep or recline position.

Alternatively, with reference to figure 14, moving the cushion frame 2 to the vertical folded position causes rotation of the cushion lug 75 relative to the squab frame 3 flirther increases the distance between the lug 75 and the squab frame cable guide to cause a greater degree of pull on the cable to move the head restraint 4 to a fully retracted position. This offers a more compact seating unit when folded, in particular improving visibility over the seat.

The horizontal fold condition of figure 15 provides correspondent relative positions of cushion and squab to that of the vertical fold condition and therefore the head rest is also in the fully retracted position.

In the preferred embodiment described, in the horizontal folded condition, the cushion is lowered beyond the normal seating position. Therefore, the spring link 73 provides a small extra extension of the cable 70 in the event that the squab 4 is deployed to the normal seating position before the cushion is moved thereto.

In a seating unit where movement of the cushion support frame 2 relative to the base module 5 is not provided for, the cushion end 72 of the actuator cable 70 could be fixed to any suitable reference point on the base module 5.

16

Claims (21)

1. A vehicle seating unit comprising a base module, a cushion support frame and a squab support frame mounted on a common axis of rotation, and a coaxial folding mechanism for controlling the angles between the cushion support frame and the base module, and between the squab support frame and the base module.

2. A vehicle seating unit according to claim 1 in which said coaxial folding mechanism is adapted to enable folding of the seating unit such that both the cushion support frame and squab support frame can be folded together to lie substantially parallel to one another in both nearhorizontal and near-vertical planes.

3. A vehicle seating unit according to claim 1 or claim 2 in which said coaxial folding mechanism is adapted to allow positioning of the cushion support frame and the squab support frame at a plurality of discrete angles relative to the base module.

4. A vehicle seating unit according to claim 3 in which said coaxial folding mechanism comprises a cushion support plate and a squab support plate coaxially mounted on a pivot, each support plate including a plurality of detents for engagement with a locking pin to determine the positions of said cushion support frame and squab support frame.

5. A vehicle seating unit according to claim 3 in which said support plates each include an arcuate slot therein, said arcuate slots including said detents; said locking pin comprising a travelling pin extending at least partly into each slot, wherein disengagement and re-engagement of 17 said travelling pin in detents in said arcuate slots is facilitated by movement of the travelling pin in a direction transverse to planes of said support plates.

6. A vehicle seating unit according to claim 5 in which disengagement and re-engagement of said travelling pin in detents in said arcuate slots is facilitated by movement of the travelling pin in a direction parallel to the axis of said pivot.

7. A vehicle seating unit according to claim 5 or claim 6 in which each arcuate slot includes at least one shoulder at a selected depth in said slot, said shoulders being punctuated at intervals along said arcuate slot by cut-away portions adapted to receive a shouldered portion of said travelling pin.

8. A vehicle seating unit according to claim 7 in which said cutaway portions act as escapements to allow passage of a shouldered portion of the travelling pin between rebates in the arcuate slots.

9. A vehicle seating unit according to any one of claims 5 to 8 in which said travelling pin has at least four longitudinal positions each one of which corresponds to one of: cushion and squab locked in selected positions; cushion locked in a selected position and squab free to move; squab locked in a selected position and cushion free to move; and both 25 cushion and squab free to move.

10. A vehicle seating unit according to claim 9 further including an actuation mechanism adapted to drive the travelling pin to a selected one of said at least four positions.

18

11. A vehicle seating unit according to any one of claims 1 to 10, further including a head restraint frame pivotably coupled to said squab support frame, the head restraint support frame being adapted to assume variable angles according to the relative angle between the squab support frame and the cushion support frame.

12. A vehicle seating unit according to claim 11 further including a control cable or link extending along said squab support frame and 10 linking said cushion support frame to said head restraint support frame.

13. A vehicle seating unit according to claim 12 in which the control cable or link includes means for extending its effective length against a bias.

14. A vehicle seating unit according to claim 11 or claim 12 in which said head restraint support frame is biassed toward a position substantially in-line with the long axis of the squab support frame when the squab is in a normal deployed condition.

15. A vehicle seating unit according to claim 14 in which the head restraint support frame is adapted to automatically tilt forward, with respect to the squab support frame, when the squab support frame assumes a reclined condition.

16. A vehicle seating unit according to claim 14 or claim 15 in which the head restraint support frame is adapted to automatically tilt forward, with respect to the squab support frame, when the cushion support frame assumes a vertical folded condition.

19

17. A vehicle seating unit according to any one of claims 14 to 16 in which the head restraint support frame is adapted to automatically tilt forward, with respect to the squab support frame, when the cushion support frame and the squab support frame both assume a horizontal folded condition.

18. A vehicle seating unit comprising a base module, a cushion support frame and a squab support frame, said squab support frame having an adjustable angle relative to at least one of said base module or said cushion support frame, the seating unit further including a head restraint frame pivotably coupled to said squab support frame, the head restraint support frame being adapted to assume variable angles according to the relative angle between the squab support frame and the base module or cushion support frame.

19. A vehicle seating unit according to claim 18 further including a control cable or link extending along said squab support frame and linking said cushion support frame or said base module to said head restraint support frame.

20. A vehicle seating unit according to claim 19 in which the control cable or link includes means for extending its effective length against a bias.

21. A vehicle seating unit substantially as described herein and with reference to the accompanying drawings.