GB2304554A

GB2304554A - Vehicle seat for the disabled

Info

Publication number: GB2304554A
Application number: GB9517935A
Authority: GB
Inventors: Guy Morse-Brown
Original assignee: MORSE BROWN GUY
Current assignee: MORSE BROWN GUY
Priority date: 1995-09-02
Filing date: 1995-09-02
Publication date: 1997-03-26
Anticipated expiration: 2015-09-02
Also published as: GB2304554B; GB9517935D0

Abstract

A vehicle seat 10 having a seat cushion 12 and a back 14, is mounted on a sub-frame 16 to the floor of a vehicle for rotation about a vertical axis between a first position in which the seat is directed forwardly and a second position in which it is directed transversely towards an adjacent exit of the vehicle. A lifting mechanism comprising parallel links 50,52 and a double acting hydraulic ram 62 moves the seat, when in its second position, outwardly through the exit and downwardly, said mechanism extending vertically behind the seat back in juxtaposed relationship thereto.

Description

VEHICLE SEATS The present invention relates to vehicle seats and in particular to vehicle seats for disabled persons.

In accordance with one aspect of the present invention, a vehicle seat comprises a seat cushion and seat back, the seat being mounted on a sub-frame to the floor of a vehicle for rotation about a vertical axis between; a first position in which the seat is directed forwardly; and a second position in which the seat is directed transversely towards an adjacent exit of the vehicle; a lifting mechanism being provided for moving the seat outwardly through the exit and downwardly, when the seat is in its second position, said lifting mechanism extending vertically behind the seat back in juxtaposed relationship to the seat back.

Locating the lifting mechanism in or behind the seat back, vertically in juxtaposed relationship thereto, permits the unobtrusive use of a relatively tall mechanism which will allow the seat to be moved vertically and horizontally to an appreciable extent. A seat according to the present invention is consequently particRulasly svitable for use with taller road vehicles, such as the Mitsubishihogun)or Range Rover ere the seating position in the vehicle will be significantly above the level of a person seated in a wheelchair at ground level.

According to a preferred embodiment of the invention, the lifting mechanism comprises a parallelogram linkage connecting the seat to the sub-frame, the parallelogram linkage acting between the sub-frame and an upper part of the seat back, so that; when the seat back is raised and in the first or second position, the parallelogram linkage extends substantially vertically in juxtaposed relationship to the seat back; and when the seat is lowered, the parallelogram linkage extends substantially horizontally, the seat being maintained in substantially its normal elevation to the horizontal throughout its travel. Drive and/or resilient means acts across a diagonal of the parallelogram linkage to move the seat from its raised to its lowered position and vice versa.

An embodiment of the present invention is now described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a partial plan view of the passenger compartment of a vehicle showing a seat in accordance with the present invention in a first position; Figure 2 is a view similar to Figure 1 showing the seat in a second position; Figure 3 is a partial sectional side elevation of the seat illustrated in Figure 1; Figure 4 is a side elevation of the seat in the position illustrated in Figure 2, shown in both the raised and lowered position; Figure 5 is a plan view of the seat illustrated in Figure 4, in the lowered position; Figure 6 is a plan view of a sub-frame of the seat illustrated in Figure 1; Figure 7 is a section along the line VII-VII of Figure 6; Figure 8 is a section along the line VIII-VIII of Figure 6;; Figure 9 is a section along the line IX-IX of Figure 6; Figure 10 is a side elevation along the line X-X of Figure 6; Figure 11 is a partial plan view of the seat in the position illustrated in Figure 2; Figure 12 is a detailed section along the lines XII-XII of Figure 4, with the seat in the second position; and Figure 13 is a diagrammatic illustration of the hydraulic circuit of the seat in accordance with the present invention.

As illustrated in the accompanying drawings, a vehicle seat 10 comprises a seat cushion 12 and seat back 14 which are located on a frame 16.

The frame 16 comprises a pair of parallel space members 18 connected together by cross-members (not shown). The members 18 define the horizontal portion 19 for supporting the seat cushion 12 and a vertically extending portion 20 for supporting the seat back 14. The width of each of the members 18 increases towards the upper end 21 of the vertical extending portions 20.

A sub-frame 30 is secured to the floor 32 of the vehicle. The sub-frame 30 has a platform 34 mounted thereon for rotation about a vertical axis by means of a stub axle 36, which is secured to the sub-frame 30 adjacent the outer edge 38 thereof and towards the rear of the sub-frame 30.

The platform comprises a flat base plate and has a cradle 40 mounted to the upper face thereof, the cradle 40 comprising a pair of space parallel members 42 and having upstanding portions 44 towards the rear end of the platform 34.

The seat frame 16 is mounted on the platform 34 by means of a pair of links 50 and 52. The links 50 and 52 are of equal length and are attached between the upper ends 21 of members 18 of the seat frame 16 and the upstanding portions 44 of members 42 of the cradle 40, by means of pivotal connections 54, 56 and 58, 60 respectively.

The pivotal connections 54 and 56 are spaced both longitudinally and vertically and the pivotal connections 58 and 60 are spaced both longitudinally and vertically to the same extent, so that the links 50 and 52 define a parallelogram linkage.

A double acting hydraulic ram 62 is connected between pivots 56 and 58, so that lengthening of the ram 62 will cause the links 50 and 52 to move towards the vertical while shortening of the ram 62 will cause the links 50 and 52 to move towards the horizontal. The ram 62 is connected to a battery or engine driven hydraulic system by flexible hoses or pipes and rotary couplings, not shown.

As illustrated in greater detail in Figure 6, plates 70 and 72 are secured to the sub-frame 30 and have arcuate slots 74 and 76 which are on a circle centred on the axis of axle 36. As illustrated in Figure 7, a stop 78 is secured to the underside of the platform 34, to engage the arcuate slots 74 and 76 at the extremities of the rotational motion of the platform 34 relative to the sub-frame 30. As shown, the stop 78 has a head formation 80 the diameter of which is greater than the width of the slots 74 and 76 and which will underlie the plates 70 and 72, to prevent lifting of the platform 34. The upper edge 82 of the head formation is chamfered to provide a lead-in.

A groove formation 84 as illustrated in Figure 8 is also provided on the sub-frame 30 for engagement by a tongue 86 on the platform 34, when the platform 34 is rotated so that stop 78 engages slot 74.

The platform 34 is mounted on stub axle 36 so that there is normally a clearance between the sub-frame 30 and platform 34 to allow free rotation thereof. Pads 88 and 90 as illustrated in Figure 9 are provided on the sub-frame 30 and platform 34 for interengagement with a small predetermined clearance between, when the platform 34 is at its limits of rotation relative to the sub-frame 30.

When the seat 10 is in the first position, a small pre-set clearance is provided between stop 78 and the top and bottom of plate 70, and between the top and bottom of the tongue 86 and groove formation 84, to allow free movement into and out of the first position. Any load being applied due to vehicle braking (or collision) causes the clearances to be taken up and the seat held rigidly in relation to the vehicle.

In a similar manner, when the seat 10 is in the second position, a small pre-set clearance is provided between stop 78 and the top and bottom of plate 72, and between pads 88 and 90, to allow free movement into and out of the second position. When the seat 10 extends outwards and downwards, the turning moment thus generated, causes the clearances to be taken up, and resistance is thus provided, to prevent undue bending stresses from being applied to the stub axle 36.

As illustrated in Figure 12, a pair of tapered pins 130 are secured to the forward cross-member 132 on the seat frame 16. The pins 130 are arranged to engage in nylon snap-in bushes 134 located in the front cross-member 136 of the platform 34, so as to locate the seat frame 16 with respect to the platform 34, when the seat is in its raised position.

As illustrated in Figure 6, a latch mechanism 90 is provided to lock the platform 34 relative to the sub-frame 30 when stop 78 engages the slot 74. The latch mechanism 90 comprises a lever 92 which is biased upwardly by spring 94. When stop 78 engages slot 74, a latch 96 on lever 92 engages the forward cross member 132 on the seat frame 16, as illustrated in Figure 10. This prevents the vehicle seat 10 on its platform 34, from rotating and at the same time prevents the vehicle seat 10 on its frame 16, from moving forward in relation to the platform 34. A latch release pin 102 is slidingly located on the forward cross member 132 and is controlled by cable operated means (not shown), to push the lever 92 against the load applied by spring 94 and disengaging the latch 96 from the forward cross member 132.This permits the platform 34 to be rotated relative to the sub-frame 30, and at a later position, the vehicle seat 10 in its frame 16, to move forward in relation to platform 34. A nylon block 104 is secured to the latch 96 and engages the underside of the platform 34 as it is rotated, maintaining the latch 96 in the disengaged position while the platform 34 is away from the first position.

A switch 106 is controlled by movement of latch 96 and controls a warning light on the dashboard of the vehicle to indicate when the latch 96 is engaged.

As illustrated in Figure 11, a plate 110 is mounted on the sub-frame 30 to engage the platform 34 when at its extreme of movement illustrated in Figure 2. The plate 110 has a rubber buffer 112 to cushion the end of travel of the platform 34. A second latch 114 which is pivotally mounted to the platform 34, is arranged to engage through an aperture 116 in the plate 110 to lock the platform against the plate 110. The latch 114 is biased into engagement with the plate 110 by spring 118, a cam surface 120 on the latch 114 permitting automatic engagement with the plate 110, as the platform 34 approaches the plate 110. A cable operated pin mechanism 122 is provided for release of the latch 114.

A switch 124 is also provided for actuation by the latch 114, the switch controlling energisation of the hydraulic system, so that the system is inoperative until the latch 114 is engaged with the plate 110 and the seat is locked in the position illustrated in Figure 2.

In operation, the seat will normally be in the position illustrated in Figure 1 and will be locked in this position by the latch mechanism 90. In this position, the platform 36 is located with respect to the sub-frame 30 by means of axle 36, engagement of stop 78 in slot 74 and engagement of groove formation 84 by tongue 86.

To permit a person to enter or leave the vehicle, the latch mechanism 90 is released and the seat manually rotated until the platform engages plate 110, as illustrated in Figure 2. The latch 114 will then lock the seat in this position in which the platform 34 is supported with respect to the sub-frame 30 by axle 36, engagement of stop 78 in slot 76 and alignment of pads 88 and 90.

Actuation of switch 124 by latch 114 will then energise the hydraulic system which may be controlled by a push button handset (not shown), to drive the ram 62 so that it retracts in length causing the links 50 and 52 to rotate from the vertical to the horizontal, moving the seat out of the vehicle and downwardly from the position shown in broken line in Figure 4 to the position shown in full line in Figure 4. In the lowered position the seat is on a level with a wheelchair at ground level thereby facilitating the seating or alighting of a wheelchair bound person.

A plate 140 is mounted below the seat frame 16 for resilient movement with respect thereto, as illustrated in Figure 4. The plate 140 engages a pair of microswitches 142, so that on coming into contact with an obstruction, for example a person's foot, as the seat 10 is lowered, the plate 140 will actuate one or both switches 142, the switches deenergising the hydraulic circuit to prevent further downward movement of the seat 10.

When the seat 10 is in its lowered position the ram 62 may be controlled to reverse movement of the seat until it is back in its fully raised position as illustrated in broken line in Figure 4, when the latch 114 may be released and the seat rotated back to the position illustrated in Figure 1.

As illustrated in Figure 13, the double acting hydraulic ram 62 is powered by means of an electric motor driven pump 150. The pump 150 delivers hydraulic fluid from reservoir 152, selectively to either side 158 or 1 60 of the ram 62. The direction of movement of the ram 62 and hence raising or lowering of the seat 10 is controlled by a double solenoid valve 1 54.

On energisation of one solenoid 156 of the valve 1 54 connects side 1 58 of the ram 62 to the pump 150, while the other side of the ram 62 is connected to a drain 161 by which hydraulic fluid is fed back to the reservoir 152. The ram 62 will consequently extend causing the seat 10 to move upwardly. When solenoid 156 is de-energised and solenoid 157 energised, the valve 154 connects side 160 of ram 62 to the pump 1 50 and side 158 to the drain 161, causing the ram 62 to retract and the seat 10 to move downwardly. Flow control valves 164 and 166 are provided in the lines between the solenoid valve 1 54 and the two sides 158 and 160 of ram 62, to control the rate at which the seat 10 moves upwardly and downwardly.

The electric motor which drives pump 150 is powered from the vehicle battery. In case of power failure, a double acting hand pump 170 is provided in parallel with the electric pump 1 50. Electric pump 150 and hand pump 170 are connected to the solenoid valve 154, via a manual changeover valve 172, so that electric pump 150 or hand pump 170 may be selected as required. Alternatively, a solenoid controlled changeover valve may be used, the solenoid control changeover valve being actuated when the hand pump 170 is brought into use.

The hand pump 170 has an actuating lever 174. The lever 174 is rotatable to select either upward or downward movement of the seat 10, rotation of the lever 174 controlling microswitches to control the solenoid valve 154. A standby battery is provided to power the solenoid valve 154 in case of failure of the vehicle power supply.

Various modifications may be made without departing from the invention.

For example, while in the above embodiment raising and lowering the seat is controlled by a hydraulic ram, a pneumatic ram or an electric linear actuator or any other suitable means may be used. Power means may also be provided for rotation of the seat from its forward position as illustrated in Figure 1 to its transverse position as illustrated in Figure 2.

Resilient means, for example springs or gas springs may also be used to reduce the load on or even replace the ram or actuator.

Claims

1. A vehicle seat comprising a seat cushion and seat back, the seat being mounted on a sub-frame to the floor of a vehicle for rotation about a vertical axis between; a first position in which the seat is directed forwardly; and a second position in which the seat is directed transversely towards an adjacent exit of the vehicle; a lifting mechanism being provided for moving the seat outwardly through the exit and downwardly, when the seat is in its second position, said lifting mechanism extending vertically behind the seat back in juxtaposed relationship to the seat back.

2. A vehicle seat according to Claim 1 in which a platform is mounted for rotation on the sub-frame, the seat being mounted on the platform by the lifting mechanism.

3. A vehicle seat according to Claim 2 in which the platform is mounted for rotation on the sub-frame about an axis located adjacent the outer edge of the sub-frame and rearwardly of the sub-frame.

4. A vehicle seat according to any one of Claims 1 to 3 in which the lifting mechanism comprises a parallelogram linkage pivotally mounted at one end to the upper end of the seat back and at the lower end to the platform.

5. A vehicle seat according to Claim 1 in which parallel links of the parallelogram linkage are pivotally mounted at one end to the upper end of the seat back at vertically and horizontally spaced locations.

6. A vehicle seat according to Claim 4 or 5 in which a double acting drive means acts between diagonally opposed pivots of the parallelogram linkage.

7. A vehicle seat according to any one of Claim 4 to 6 in which the drive means is a pneumatic or hydraulic ram or electric linear actuator.

8. A vehicle seat according to any one of Claims 4 to 7 in which spring means acts between the links of the parallelogram linkage.

9. A vehicle seat according to any one of Claims 2 to 8 in which there is multiple point location of the platform with respect to the sub-frame, in both the first and second positions of the seat.

10. A vehicle seat according to Claim 9 in which a pin engages in arcuate slots at both the first and second positions of the seat.

11. A vehicle seat according to Claim 10 in which a head formation on the pin engages a remote side of a plate defining the slot, to prevent the platform from lifting away from the sub-frame.

12. A vehicle seat according to any one of Claims 9 to 11 in which a groove formation is provided on the sub-frame for engagement by a tongue formation on the platform when the seat is in its first position.

13. A vehicle seat according to any one of Claims 9 to 12 in which pads are provided on the sub-frame and platform for engagement in the first and/or second positions.

14. A vehicle seat according to any one of the preceding claims in which latch means is provided to lock the seat in the first position.

15. A vehicle seat according to Claim 14 in which means is provided to indicate that the seat is latched in its first position.

16. A vehicle seat according to any one of the preceding claims in which latch means is provided to lock the seat in its second position.

17. A vehicle seat according to Claim 16 in which means is provided to de-energise drive means of the lifting mechanism, when the seat is not latched in its second position.

18. A vehicle seat substantially as described herein with reference to and as shown in Figures 1 to 13 of the accompanying drawings.