GB2494868A - Chair with seat portion that lifts and tilts - Google Patents

Abstract

An articulated chair 10 comprises a main body portion 12, a seat portion 14 movable relative to the main body portion 12, and an articulation mechanism interposed between the main body portion 12 and the moveable seat portion 14, the articulation mechanism comprising a first connector, e.g. a rail(s) 30, rigidly connected to the moveable seat portion 14, a second connector, e.g. rail(s) 32, rigidly connected to the main body portion 12 of the chair 10 and at least one pair of linkages 34,36 pivotally connected to each of the first 30 and second 32 connectors, the linkages 34,36 of the or each pair being of different lengths. The pair of linkages preferably comprises a first forward linkage 34, and a second longer rear linkage 36 arranged such that the seat portion 12 is constrained to move about two part-circular loci 48,50, preferably from a lower level position to a raised and tilted forward position. The chair assists occupants in standing-up.

Description

TILTING CHAIRS

Description:

This invention relates to tilting chairs, and in particular, but without limitation to, tilting chairs suitable for use by the elderly and infirm.

A tilting chair is an ambulatory device that is often used by the elderly or infirm as an alternative to a conventional chair and comprises a seat portion that is articulated with respect to the main body of the chair. The seat portion can be tilted to help a user to get into and out of the chair. Frequently, the tilting mechanism is motorised and controlled by a hand-held remote controller.

Known tilting chairs generally comprise a base, and a seat portion that is hingedly connected to the base by a tilting mechanism. A tilted chair is generally easier for a user to get into and out of, because it does not require the user to bend as much, or to support their weight in a knees-bent position. Many tilting chairs also incorporate reclining functions that enable a user, once seated, to adopt a reclined or laid-flat position, which can be more comfortable and alleviate pressure pains caused by sitting in one position for extended periods.

A problem with known tilting chairs, for example, of the type described above, is that the tilting mechanism can be cumbersome, unnatural and awkward to use. In known tilting chairs, the seat portion is normally connected to the base of the chair by a hinge located at the seat's front edge corresponding approximately to the user's knee position when seated. The effect of this is arrangement, during tilting, is simply to raise the rear part of the seat portion relative to the front, which feels, to a user, like the entire chair is being tipped forwards. Users of this type of chair sometimes complain that it feels like the chair is falling forwards, or that they slip forwards during tilting of the seat, which can lead to increased strain on the user's knee, ankle and hip joints.

One known solution to this problem is use a lifting/reclining chair, such as that described in UK patent publication number GB2449248, which raises the entire chair as it tilts. This type of chair can be configured to raise the chair such the seat portion is moved to a position close to the user's standing buttock height, which means that the user's weight can be transmitted downwardly through a more natural, nearly-standing position, when mounting or alighting the chair.

Lifting/reclining chairs of this type, however, tend to be considerably more bulky, complicated and expensive than their tilting chair counterparts, which can render lifting/reclining chairs unsuitable in some circumstances.

A need therefore arises for a hybrid type of articulated chair that combines the advantages of a lifting/reclining chair with the smaller size and reduced complexity of a conventional tilting chair. This invention aims to provide such a hybrid type of chair, an improved tilting chair and/or an alternative to known tilting and lifting/reclining chairs.

According to the invention there is provided an articulated chair comprising a main body portion, a seat portion movable relative to the main body portion, and an articulation mechanism interposed between the main body portion and the moveable seat portion, the articulation mechanism comprising a first connector rigidly connected to the moveable seat portion, a second connector rigidly connected to the main body portion of the chair and at least one pair of linkages pivotally connected to each of the first and second connectors, the linkages of the or each pair being of different lengths.

The effect of providing linkages of different lengths is to constrain spaced apart points on the first and second connectors to move reiative to one another along different arcuate Pod. The loci are determined by the geometry of the connectors and linkages, but are preferably configured to cause, in use, the seat portion to lift and tilt (or lower and level) during articulation of the articulation mechanism. Most preferably, the geometry of the connectors and linkages is selected to cause a front edge of the seat to move forwards and upwards during tilting and a rear portion of the seat to move upwards, and optionally forwards, during tilting of the seat (or vice-versa when lowering/levelling the seat). By causing the seat to move upwards during tilting, the front edge of the seat can be raised to a height that corresponds to a point on the back of a user's thigh and the rear of the seat portion can be raised to a height corresponding to the height of a user's buttocks, thereby facilitating, in use, boarding or alighting the chair. Moreover, where the front edge of the seat portion is caused to move forwards relative to the main body of the chair during tilting, it becomes possible for a user's heels to be placed below the front edge of the seat portion, without interfering with the main body of the chair, during boarding and alighting the chair, thereby affording the user greater purchase when standing from the chair or lowering themselves into it.

Advantageously, because the articulation mechanism of the invention only causes relative movement of the chair portion relative to the main body of the chair, it is not necessary to lift the entire chair, making for a considerably more compact construction than a known lifting/reclining chair. In addition, because the main body of the chair remains still, the back of the chair does not need to tilt forwards as the seat portion is tilted, thereby removing the feeling of being pushed out of the chair.

The chair's armrests, a portion of the chair's armrests, or handles may be connected to the moveable seat portion to conveniently provide raised hand-holds to help a user board or alight the chair.

The articulation mechanism is preferably motorised, and may comprise a controller for controlling the operation of an actuator, such as an electric motor. Most preferably, the actuator comprises a telescopic actuator and most preferably, an electric motor driven telescopic actuator.

Entrapment prevention means is also preferably provided to prevent foreign objects from becoming entrapped between relatively moveable portions of the chair. The entrapment prevention means may comprise one or more sensors affixed to various parts of the chair and operatively connected to the controller for sensing the presence of an obstruction, the at least one sensor and controller preferably being together arranged to stop and reverse the actuator when the presence of an obstruction is sensed. The entrapment prevention means may reduce or eliminate the risk of an object becoming trapped underneath, or by, the chair during tilting or lowering/levelling of the seat portion.

The at least one sensor, where provided, may be arranged to sense the presence of an obstruction located between the seat portion and the main body portion of the chair. Additionally or alternatively, at least one sensor may be located within the seat portion and arranged to sense the presence of a person sitting on the chair.

The sensor, where provided, may comprise a pressure sensor which sensor could comprise first and second resiliently deformable webs each having at least one electrically conductive surface, the webs being maintained in a spaced apart relationship but being deformable so to enable the electrically conductive surfaces to be brought into contact with one another. An apertured, resiliently compressible web may be located between the first and second electrically conductive webs and optionally, at least one of the first and second webs may comprise a plurality of projections that project at least partially into the apertures of the resiliently compressible web, the projections being arranged so as to reduce the separation between opposing conductive surfaces of the first and second webs. The pressure sensor may comprise a pair of spaced-apart resiliently deformable electrical contacts with a discontinuous resiliently deformable spacer therebetween.

Preferably, the sensor or sensors comprises a flexible polymeric support web having a metallic coating on one surface thereof. The resiliently deformable spacer may comprise a web of apertured foam.

A preferred embodiment of the invention shall now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of a tilting chair in accordance with the invention in a lowered position; Figure 2 is a perspective view of the tilting chair of Figure 1 in a tilted position; Figure 3 is a schematic side view of the tilting mechanism of a known tilting chair; Figure 4 is a schematic side view of the articulation mechanism of a tilting chair in accordance with the invention; and Figure 5 is a is a perspective view of the articulation mechanism of Figure 4.

In Figure 1, a tilting chair 10 comprises a main body portion 12 and a movable seat portion 14. The main body portion 12 comprises a base portion 16 that is supported above the floor on four substantially vertical legs 18. The main body portion 12 is of a generally conventional design having a wing back portion 20 and a pair of armrests 22 located either side of the seat portion 14. When the seat 14 is in a lowered position, as shown in Figure 1, the chair 10 can be used like any other armchair. In a known armchair, the seat portion 14 would normally be removable to enable it to be flipped periodically, and in that sense, the main body portion 12 of the chair 10 is of a generally conventional design.

However, as can be seen from Figure 2, the seat portion 14 is mounted on articulation mechanism 24 to enable it to be tilted to assist a user (not shown) in mounting, and alighting, the chair 10. The seat portion 14 is movable relative to the main body portion 12 and is constrained by the articulation mechanism 24 to rise and tilt forwards to a raised and inclined position has shown in Figure 2. The articulation mechanism 24 is motorised and controlled by a hand-held remote control 26 that can be stowed, when not in use, in a pocket 28 located on the exterior side of an arm 22 of the chair 10. The remote control 25 has a number of pushbuttons, which, when depressed, cause the motorised articulation mechanism 24 to move the seat portion 14 relative to the main body portion 12 of the chair 10.

Figure 3 is a schematic side view of the tilting mechanism of a known tilting chair 80, which also comprises a main body portion 82 and a movable seat portion 84. The movable seat portion 84 is screwed, or otherwise affixed, to a pair of parallel mounting rails 86, which are pivotally connected at, or towards, their front ends 88 to a further pair of mounting rails 90 screwed, or otherwise affixed, the main body portion 82 of the chair 80. A telescopic motor 92 is pivotally connected between the mounting rails 86, 90 and by extending or retracting telescopic motor 92, the movable seat portion 84 can be tilted forwards (as shown in Figure 3) or lowered to a substantially horizontal position (not shown). In the known tilting mechanism 80, the front edge of the movable seat portion 84 pivots about a fixed point 88, whereas the rear edge 94 of the movable chair portion 84 moves along a part-circular locus and 96. In the known tilting chair 80, the movable seat portion 84 simply pivots substantially about its front edge.

Figure 4 shows an articulation mechanism 24 for a tilting chair 10 in accordance with the invention. In Figure 4 it will be noted that the movable seat portion 14 is mounted on a pair of parallel seat connector rails 30 in a similar manner to that described in relation to Figure 3.

However, rather than the seat connector rails 30 being pivotally connected to the main body portion 12 of the chair 10 at a fixed pivot point 58, the seat connector rails 30 are pivotally connected to a pair of parallel mounting rails 32 via a pair of hingedly connected linkages 34, 36 of different lengths: the forward linkage 34 being shorter in length than the rear linkage 36.

The forward linkages 34 are pivotally connected at their lower ends to points 38 located towards the front of the mounting rails 32, and at their upper ends, to points 40 set slightly back from the front ends of the seat connector rails 30. The length of the forward linkages 34 and the positions of points 38 and 40 are selected such that when the moveable seat portion 14 is in a lowered position, as indicated by dashed iines 42, the seat connector rails 30 lie substantially parallel to the mounting rails 32 and the front ends of the seat connector rails 30 and the mounting rails 32 are substantially vertically aligned.

The longer rear linkages 36 are similarly pivotally connected between the seat connector rails 30 and the mounting rails 32: the lower ends of the rear linkages 36 being connected to the mounting rails 32 at points 42 located rearward of points 38, and at their upper ends to points 44 located towards the rear of the seat connector rails 30. Likewise, the length of the rear linkages 36 and the positions of points 42 and 44 are selected such that when the moveable seat portion 14 is in a lowered position, as indicated by dashed lines 42, the seat connector rails 30 lie substantially parallel to the mounting rails 32 and the rear ends of the seat connector rails 30 and the mounting rails 32 are substantially vertically aligned.

A motorised telescopic actuator, as indicated schematically by bold chain-dot line 46, is operatively and pivotally connected to the seat connector rails 30 and the mounting rails 32.

Extension of the telescopic actuator 46 causes the moveable seat portion 14 to move towards a tilted position (as shown), and conversely, retraction of the telescopic actuator 46 causes the moveable seat portion 14 to move towards a lowered position.

As can be seen in Figure 4, the articulation mechanism 24 causes moveable seat portion 14 to be constrained to move about two part-circular loci 48, 50, centred, respectively on points 38 and 42. Such a mechanical constraint causes the moveable seat portion 14 to translate vertically and horizontally (as shown in Figure 4) as it tilts forwards, and vice-versa: intermediate positions of the seat connector rails 30 being indicated by dotted lines 52.

It will be appreciated that the end limit position of moveable seat portion 14 can be selected to adopt a desired position and orientation relative to the main body portion 12 of the chair by altering the geometry of the linkages 34, 36 and the travel of the telescopic actuator 46. In many situations, it will be desirable to select a limit position of the moveable seat portion 14 that sees the front edge 54 thereof raised and moved forwards with respect to the main body portion 12 of the chair io. such a position corresponds, approximately, to intermediate position 52' of Figure 4. By moving the seat portion 14 forwards, a user (not shown) is able to place his or her feet (not shown) at a position 56 below the front edge 54 of the seat 14, without interfering with the legs 18 or main body portion 12 of the chair 10 when mounting and alighting the chair 10.

To guard against entrapment of foreign objects or body parts, the articulation mechanism 24 is preferably located within a housing (not shown) or skirting that prevents or inhibits the introduction of foreign objects or body parts between the main body portion 12 of the chair 10 and the movable seat portion 14. Additionally or alternatively, pressure sensors 58 are provided to detect the presence of foreign objects located between relatively movable parts of the chair 10. The pressure sensors 58 comprise electrically conductive webs that are normally maintained in a spaced-apart relationship by a resiliently deformable intermediate layer, the resiliently deformable layer being compressible during a contact event to cause the electrically conductive webs to make electrical contact with one another thereby signalling the presence of an obstruction. The sensors 58 are connected to a controller (not shown) that overrides the inputs of the remote-control 26 to stop and reverse the motion of the seat portion 14 upon detection of an obstruction. Details of such an obstruction-detection system are described in UK patent publication number GB2449248, the entire content of which is incorporated herein by reference.

Finally, Figure 5 shows, in three-dimensions, the articulation mechanism 24 of Figure 4. It will be readily appreciated from Figures, how the mounting rails 32 can be readily screwed atop the base portion of a chair and how a moveable seat portion (not shown) could be affixed to the seat connector rails. In the illustrated example of Figure 5, it will be noted that the rails 30, 32 are formed from L-section steel and that the linkages 34, 36 are formed from flat strips of steel. Pivotal connections between the rails 30, 32 and linkages 34, 36 are formed by way of through bolts that extend through apertures in the respectively connected components. In Figure 5 it will also be noted that the seat connector rails 30 are arranged to nest within the mounting rails 32 when the seat is lowered. A tubular cross-bar 60 is also provided, which comprises a pivotal attachment point 62 for one end of a telescopic motor (not shown). The connectors 30, 32 are provided with pre-drilled through apertures to facilitate screwing or otherwise affixing the articulation mechanism 24 to a chair and moveable seat portion.

The invention is not restricted to the details of the foregoing embodiment, which is merely exemplary. For example, whilst the invention has been described with reference to a single-seater armchair, there is no reason why it could not be incorporated into a multiple-seater chair, e.g. a sofa, with individual seat portions being movable independently, or in unison. In addition, the chair need not be supported above the floor on legs, but could comprise a peripheral skirting to conceal the legs, or could have a box-type base.

Claims (1)

1. <claim-text>Claims: 1. An articulated chair comprising a main body portion, a seat portion movable relative to the main body portion, and an articulation mechanism interposed between the main body portion and the moveable seat portion, the articulation mechanism comprising a first connector rigidly connected to the moveable seat portion, a second connector rigidly connected to the main body portion of the chair and at least one pair of linkages pivotally connected to each of the first and second connectors, the linkages of the or each pair being of different lengths.</claim-text> <claim-text>2. An articulated chair as claimed in claim 1, wherein spaced apart points on the first and second connectors are constrained to move relative to one another along different arcuate loci.</claim-text> <claim-text>3. An articulated chair as claimed in claim 2, wherein the articulation mechanism causes the moveable seat portion to be constrained to move about two part-circular loci.</claim-text> <claim-text>4. An articulated chair as claimed in any of claims 1, 2 or 3, wherein the moveable seat portion is constrained to lift and tilt, or lower and level, during articulation of the articulation mechanism.</claim-text> <claim-text>5. An articulated chair as claimed in any of claims 1 to 4, wherein the geometry of the connectors and linkages is selected to cause a front edge of the seat portion to move forwards and upwards, and a rear portion of the seat portion to move upwards, and optionally forwards, during tilting of the seat) or vice-versa.</claim-text> <claim-text>6. An articulated chair as claimed in any preceding claim, wherein the first connector comprises a pair of parallet seat connector rails to which the moveable seat portion is rigidly affixed.</claim-text> <claim-text>7. An articulated chair as claimed in any preceding claim, wherein the second connector comprises a pair of parallel mounting rails rigidly affixed to the main body portion of the chair.</claim-text> <claim-text>8. An articulated chair as claimed in any preceding claim, wherein each pair of linkages comprises a forward linkage and a rear linkage, the forward linkage being shorter in length than the rear linkage.</claim-text> <claim-text>9. An articulated chair as claimed in any preceding claim, further comprising an actuator operatively and pivotally connected between the first and second connectors.</claim-text> <claim-text>10. An articulated chair as claimed in any preceding claim 9, wherein the actuator comprises a motorised actuator.</claim-text> <claim-text>11. An articulated chair as claimed in claim 10, wherein the motorised actuator comprises a telescopic motor.</claim-text> <claim-text>12. An articulated chair as claimed in any of claims 9, 10 or 11, further comprising a controller for controlling the operation of the actuator.</claim-text> <claim-text>13. An articulated chair as claimed in claim 12, wherein the controller comprises a hand-held remote control.</claim-text> <claim-text>14. An articulated chair as claimed in any preceding claim, further comprising entrapment prevention means.</claim-text> <claim-text>15. An articulated chair as claimed in claim 14, wherein the entrapment prevention means comprises one or more sensors affixed to the chair, the sensor or sensors being operatively connected to the controller for sensing the presence of an obstruction, the at least one sensor and controller being together arranged to stop and reverse the actuator when the presence of an obstruction is sensed.</claim-text> <claim-text>16. An articulated chair as claimed in claim 15, wherein the sensor comprises a pressure sensor.</claim-text> <claim-text>17. An articulated chair as claimed in claim 15 or claim 16, wherein the at least one sensor is arranged to sense the presence of an obstruction located between the seat portion and main body portion of the chair.</claim-text> <claim-text>18. An articulated chair as claimed in any preceding claim, wherein the main body portion of the chair comprises a base portion that is supported above the floor on legs.</claim-text> <claim-text>19. An articulated chair as claimed in any preceding claim, further comprising armrests, armrest portions or handles operatively connected to, and adapted to move in unison with, the moveable seat portion.</claim-text> <claim-text>20. An articulated armchair according to any preceding claim.</claim-text> <claim-text>21. An articulated multi-seater chair according to any preceding claim comprising a plurality of seat portions.</claim-text> <claim-text>22. An articulated multi-seater chair according to any preceding claim 25, wherein at least one of the seat portions is articulated with respect to the main body portion of the chair, either independently, or in unison with another seat portion.</claim-text> <claim-text>23. An articulated chair substantially as hereinbefore described, with reference to) and as illustrated in, Figures 1,2,4 and 5 of the accompanying drawings.</claim-text>