GB2170700A

GB2170700A - Vehicle seat accessory

Info

Publication number: GB2170700A
Application number: GB8602918A
Authority: GB
Inventors: Serge Guy Delprat
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-02-08
Filing date: 1986-02-06
Publication date: 1986-08-13
Also published as: GB8602918D0

Abstract

A substitute seat for a car comprises a base plate (2), an intermediate plate (4), a seat plate (6) and an upholstered seat cushion (8) arranged together in stacked relationship. The intermediate plate (4) defines an annular, inwardly-facing recess (30) in which a disc (16) is received. The disc (16) is mounted to the base plate (2) by means of a stub shaft (14). The recess (30) also accommodates a disc (38) which is mounted to one end of a shaft (40), the other end of which carries a further disc (42) which is accommodated in an inwardly-facing recess (46) in the seat plate (6). The upholstered seat cushion (8) is fixedly secured to the seat plate (6). The method of mounting the plates (2, 4, 6) together allows both translation and rotation of the seat (8) relative to the car seat to which the base plate (2) is mounted. Further, the seat (8) can be turned 90 DEG relative to its normal position and pulled outwardly to project over the door cill to allow easy entry and exit from a car. <IMAGE>

Description

SPECIFICATION Vehicle seat accessory The present invention relates to a seat accessory for mounting on an existing seat or seat support in a vehicle. This accessory or, effectively, substitute seat is intended for use by back-pain sufferers, the elderly or disabled in order to increase their comfort during travel and to assist them in entering and leaving the vehicle.

When entering or leaving a car it is usually necessary to initially sit sideways on the seat and then swing round to a normal sitting position. This represents no problem for a fit person but for the elderly and disabled it can be very difficult to rotate the body on a typical car seat surface. The present invention is designed to assist this pivoting motion of the body so that the legs can be readily moved from a position at the side of the car to a position in the well of the car without undue discomfort to the spine.

During driving it is also frequently necessary to twist the body in order to see towards the rear of the car. Such manoeuvres are necessary when reversing or pulling out into traffic. This type of manoeuvre places a considerable stress on the back and can result in considerable pain or in driving becoming totally impossible forthose who suffer from back problems.

During driving around bends, it is necessary for the driver and passengers in the vehicle to support themselves against the centrifugal forces imposed by the cornering motion of the vehicle. Whilst this accommodation is made automatically and with little effort by fit people, it can produce considerable discomfort for the elderly, disabled or back-pain sufferers.

The seat accessory of the present invention is therefore intended to provide greater comfort for passengers or drivers of vehicles who are elderly, disabled or suffer from back-pain.

The present invention accordingly provides a seat accessory adapted to be placed on a vehicle seat or vehicle seat support, comprising a base plate, a seat plate, means for mounting the seat plate such that the seat plate can rotate relative to the base plate, and bearing means interposed between said plates.

Such an accessory is readily used in conjunction with a car seat in order to make it easier for a driver or passenger to get in and out of the car, and is particularly advantageous in that it avoids painful spinal torsion especially when alighting.

In a preferred embodiment, the seat plate is provided with an annular, inwardly-directed flange extending from its periphery to define an inwardlyfacing recess in the interior of the seat plate with a central opening, the seat plate mounting means comprising a disc mounted on a shaft, the shaft extending through the opening and the edge portion of the disc being accommodated within said recess.

This mounting is advantageous in that the disc can slide around within the recess enabling simultaneous rotation and translation of the seat plate relative to the shaft. Such a motion allows the whole of the seat plate to be pulled forward to an extent limited by the size of the opening, and rotated through 90" so as to allow entry and exit from the vehicle. Motion of a more limited extent allows a "floating" effect to be obtained. Such a "floating" motion facilitates readjustment of the sitting position and takes up cornering forces imposed on the user. The "floating" motion comprises rotation through a small angle either side of the straightahead position and limited forward and backwards motion.

In one embodiment of the invention the shaft of the mounting means is fixed to the base plate. In a further embodiment an intermediate plate is provided, which plate comprises upper and lower annular surfaces defining therebetween an inwardly-facing, interior recess with openings into it in both surfaces, the shaft of the seat plate mounting means carrying a second disc which is received in said interior recess of the intermediate plate, the mounting means further comprising a shaft fixed to the base plate and carrying a third disc which is received in the interior recess of the intermediate plate.

The provision of the intermediate plate allows a longertranslatory stroke of the seat plate relative to the base plate to take place, without requiring the size of the components to be unduly large.

In a preferred embodiment, the intermediate plate is provided with an upstanding peg on its upper surface towards the rear periphery thereof, and the seat plate is provided with an abutment surface at the rear thereof on its the lower surface, the peg engaging with the abutment surface during normal driving and the abutment surface being so shaped as to permit limited rotation during driving and prevent forward motion of the seat plate relative to the intermediate plate.

The presence of the peg and abutment surface controls the "floating" motion of the seat plate by allowing limited rotation, which in a preferred embodiment is limited to 30 either side of the straightahead position so that the sitter is always in line with the road as the vehicle corners or moves round bends.

Preferably the seat plate carries an upholstered seat cushion fixedly attached to it to provide greater comfort to the user.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a cross-section through the substitute seat accessory of the present invention, taken along the line A-A of Figure 4; with the seat cushion omitted for clarity; Figure 2 is a cross-section through the seat accessory of Figure 1 taken along the line BOB of Figure 4, with the seat cushion removed for clarity; Figure 3 is a plan view of the seat plate of the seat accessory of Figures 1 and 2; Figure 4 shows a plan view of the base plate and intermediate plate of the seat accessory of Figures 1 and 2; Figures 5 and 6 are diagrams illustrating various motions which the seat accessory of the present invention can make; and Figure 7 shows a detail of the opening in the seat plate.

The seat accessory comprises a base plate 2, an intermediate plate 4, a seat plate 6, and an upholstered seat cushion 8, mounted together in a stacked arrangement.

The base plate 2 is shaped to fit over the surface of the existing seat of a vehicle and the side edges (see Fig. 1) are slightly downturned to engage over the edges of the existing seat. Openings 10 are provided at each side to receive strap portions 12 which can be buckled together underneath the seat to firmly mount the base plate on the seat so that no relative motion can take place between the existing seat and the base plate 2. The base plate 2 carries a centrally located, upstanding stub shaft 14 to which is fixed a disc 16 of larger diameter than the shaft.

The intermediate plate 4 comprises two annular members 20, 22 which are joined together at the periphery of the lower member 20. It will be appreciated that the whoie of the intermediate plate 4 can be integrally moulded in one piece. At the front of the intermediate plate 4 a handle section 24 is formed for ease of carrying.

The two annular members 20,22 define an annular, inwardly-facing recess 30. The radially outer periphery 32 of the recess 30 is circular in plan.

The inner edge of the recess is defined by circular openings 34 and 36 formed at the centre of the upper and lower annular members 20,22 respectively. As illustrated in Figures 2 and 4the openings 34 and 36 are offset with respect to one another along the longitudinal direction of the seat.

The inwardly-facing recess 30 of the intermediate plate 4 houses the disc 16 mounted on the stub shaft 14. The diameter of the opening 34 of the lower annular member is smaller than the diameter of the disc 16 so that the latter cannot escape from the recess 30. The recess 30 also accommodates a further disc 38 which is mounted to one end of a shaft 40. The other end of the shaft 40 carries a larger diameter disc 42. The diameter of the opening 36 is smaller than the diameter of the disc 38 so that the latter cannot escape from the recess 30. Discs 16 and 38 have smooth surfaces so that they can slide freely relative to one another.

The upper surface of the intermediate plate is provided with an upstanding stop peg 39 positioned just inwardly of the periphery and at the centre-back position in use.

An annular bearing member 26 is accommodated between the lower surface of the intermediate plate 4 and the surface of the seat plate. The bearing member 26 surrounds the shaft 14. The bearing member 26 houses a plurality of ball bearings 28 which are positioned so as to engage with both the lower surface of the intermediate plate 4 and the upper surface of the base plate 2. The bearing member 26 is free to move both in rotation and translation relative to the plates 2,4 and facilitates the movement of the intermediate plate relative to the base plate. The bearing member 26 cannot escape from between the plates 2,4 since it surrounds the shaft 14.

The seat plate 6 has a somewhat bowed upper surface to which the upholstered seat cushion 8 is mounted. From the outer peripheral surface of the seat plate 6 an annular, inwardly-directed flange 44 extends in order to define an inwardly-facing recess 46 in the interior of the seat plate 6. A central opening 48 is defined by the inner edge of the flange 44 and is trigonal that is of generally triangular plan with arcuate apices and curved sides as best shown in Figure 3. The opening 48 is surrounded by a downwardly directed retaining wall 50. The recess 46 has an outer peripheral edge 52 which is also of a substantially triangular shape with arcuate apices and curved sides as best shown in Figure 3. The opening 48 is sized so that its largest dimension is smaller than the diameter of the disc 42 so that when this disc is accommodated in the recess 46 it cannot escape therefrom.The forward arcuate apex of the recess 46 is curved so that it matches the radius of the disc 42 and the disc 42 seats snugly in this forward arcuate apex in the normal driving position of the seat plate.

The seat plate 6 is also provided on its lower surface with a downwardly projecting member 54 which defines an inwardly facing abutment surface 56. This surface engages in a normal driving position of the seat plate with the peg 39 formed on the upper surface of the intermediate plate.

As illustrated in Figures 1 and 2, the seat plate 6 is connected to the intermediate plate 4 by means of the dumb-bell member comprising the shaft 40 and discs 38,42. The disc 38 is housed in the interior recess 30 of the intermediate plate 4, and the disc 42 is housed in the interior recess 46 of the seat plate 6.

An annular bearing member 60 surrounds the shaft 40 and is disposed between the plates 4 and 6.

The bearing member 60 is similar to the bearing member 26 between the base plate 2 and intermediate plate 4, although it is of larger diameter. The retaining wall 50 surrounding the opening 48 prevents the bearing member 60 from passing underneath it between the plates.

As shown in Figure 1,the shaft 40 is normally positioned centrally with respect to the width of the assembly. However, in a normal driving position, the shaft 40 is positioned forwardly of the shaft 14 as shown in Figures 2 to 4.

The upholstered seat cushion 8 is fixed to the seat plate 6, preferably by means of adhesive.

The plates 2,4, 6 are preferably made out of a flexible plastics material which has sufficient rigidity to support the weight of the sitter without preventing movement of the plates relative to one another. The lower surface of the base plate 2 may be roughened or otherwise treated so that it remains stationary on the car seat.

In use, the substitute seat is placed on a car or other vehicle seat and the straps 12 fastened together to fixthe substitute seat to the existing seat. Normally the seat is positioned as shown by the entire line in Figure 5. In this position the shaft 40 is located slightly forward of the shaft 14 and both shafts are positioned centrally with respect to the width of the seat. In this position the disc 42 adopts the position shown in Figure 3. The stop 39 engages the abutment surface 56 centrally as shown in Figure 2. As illustrated in Figure 3, the shaft 40 is slightly spaced from the forward apex of the substantially triangular opening 48. This arrangement of the parts permits a limited "floating" motion of the seat cushion 8 and seat plate 6 relative to the existing seat. This motion is diagrammatically illustrated in Figure 5.This motion is primarily rotational and is effectively limited to 30 either side of the straight ahead position. A certain small translatory motion may be achieved by relative movement of the shaft 14 in the opening 34 of the intermediate plate. This "floating" motion allows the sitter to maintain a balanced position which is always in a straight line with the road, as the car negotiates bends and corners. It also enables the sitter to readjust his sitting position for relaxation. This arrangement also enables sufficient rotation to allow a driver to turn to look towards the rear as when reversing or pulling out into a stream of traffic without requiring undue muscular tension.

The degree of motion permitted by the assembly helps to improve or correct the vertical spinal position of the user during driving and allows easy shifting of the seat position. The motion also prevents torsion in the spine which is normally necessary to allow the user to turn towards the rear.

The function of the intermediate plate 4 is mainly to provide stabilisation of the seat plate. For example when the car is travelling downhill the intermediate plate is able to maintain the seat in a horizontal orientation. The spaced members 20, 22 allow compressive forces to be absorbed resulting in a more comfortable ride over bumpy ground.

The seat accessory is also capable of performing the manoeuvre illustrated diagrammatically in Figure 6 which enables easy entry and exit from the vehicle. To perform this motion the seat is rotated firmly to one side so that the abutment peg 39 moves out of engagement with the abutment surface 56. This requires more than the normal degree of force imposed on the seat by the user in order to allow the peg 39 to move over the edge of the abutment surface past its normal limit of motion.Once the peg is disengaged from the abutment surface it is possible to move the seat plate 6 backwards relative to the base plate 2 so that a fixed point performs the motion shown in Figure 6 and the whole upholstered seat part 8 is then disposed at 900 to its normal orientation and extends outwardly so that it projects over the door cill of the vehicle and the user can easily enter or leave the vehicle as required.

With the upholstered seat part 8 in the position shown in Figure 6 a user will sit on the seat, swing his legs over the cill of the car door and push himself gently round to 90" and then backwards. The backwards motion will cause the peg 39 to engage on the abutment surface 56 and disc 42 to engage against the arcuate apex edge 52 in its recess 46.

This produces a semi-locking effect where it is not possible for the seat to move through more than 30 to either side of the straight forward direction during driving. This limits the degree of motion possible during driving to prevent undue oscillation on bumpy roads but yet compensates for forces imposed on the user without requiring muscular contractions of the user. The extent of this "floating" motion is illustrated in Figure 5 by chain lines.

It will be noted that the ratios of curvature between plates 2 and 4 and between plates 4 and 6 may be different. The curvature may be more accentuated between the base of the intermediate plate 4 and the plate 2.

The reason for this accentuation of curvature is to enable the plate 6 and intermediate plate 4 to oscillate around the shaft 14 but restricted by the edge of opening 34 so that plates 4 and 6 can maintain substantially their generally horizontal attitude in relation to base plate 2.

This oscillating motion allows for a compensatory stabilizing factor whatever the longitudinal or transverse attitude of the vehicle in relation to the road, thus enabling the user to retain effortlessly a substantially constant spinal vertical position.

In a modification of the substitute seat part alternatively termed a seat accessory (not illustrated) it is possible to eliminate the intermediate plate altogether so that the disc 16 mounted to the base plate engages directly in the chamber of the seat plate 6. Such a device allows for the same 90" rotation to allow easy entry and exit from the seat as well as limited motion during travel. However, it is not possible for the seat part to be pulled any significant distance forward so that it overlaps the edge of the car as shown in Figure 6, without making the dimensions of the disc undesirably large.

If desired further annular bearing members may be provided of larger or smaller diameter than the bearing members 26 and 60 illustrated. The bearing members may move independently of one another and do not necessarily remain concentric. Several bearing members are desirable for larger versions of the design suitable for use by larger and heavier persons.

Claims

1. A seat accessory adapted to be placed on a vehicle seat or vehicle seat support, comprising a base plate, å seat plate, means for mounting the seat plate such that the seat plate can rotate relative to the base plate, and bearing means interposed between said plates.

2. A seat accessory as claimed in claim 1, wherein the seat plate is provided with an annular, inwardlydirected flange extending from its periphery to define an inwardly-facing recess in the interior of the seat plate with a central opening, the seat plate mounting means comprising a disc mounted on a shaft, the shaft extending through the opening and the edge portion of the disc being accommodated within said recess.

3. An accessory as claimed in claim 2, wherein the shaft of the seat plate mounting means is fixed to the base plate.

4. An accessory as claimed in claim 2, wherein an intermediate plate is provided, which intermediate plate comprises upper and lower annular surfaces defining therebetween an inwardly-facing, interior recess with openings into it in both surfaces, the shaft of the seat plate mounting means carrying a second disc which is received in said interior recess of the intermediate plate, the seat plate mounting means further comprising a shaft fixed to the base film carrying a third disc which is received in the interior recess of the intermediate plate.

5. An accessory as claimed in claim 4, wherein the intermediate plate is provided with an upstanding peg on its upper surface towards the rear periphery thereof, and the seat plate is provided with an abutment surface at the rearthereofon its lower surface, the peg engaging with the abutment surface during normal driving, and the abutment surface being so shaped as to permit limited rotation during driving and prevent forward motion of the seat plate relative to the intermediate plate.

6. An accessory as claimed in any one of the preceding claims, wherein the seat plate carries an upholstered seat cushion fixedly attached to it.

7. A seat accessory substantially as herein described with reference to the accompanying drawings.