GB2515498A - Chair with telescopic hinge - Google Patents

Abstract

A seat comprises a frame and seat 2, back 1 and leg supports 3, the back and leg supports being moveable between an upright seating configuration and a reclined configuration. The back and seat supports are connected by a pivotal linkage comprising a telescopic member (19, figure 7) and a hinge (18, figure 7). The seat includes an actuator (25, figure 2) adapted to move the back support between reclined and upright configurations when carrying an occupant. The connection between the hinge and seat is extendable so that the distance between the hinge pivot and seat increases as the back moves from a reclined position to an upright position and decreases as the back moves from an upright position to a reclined position. The telescopic hinge aims to reduce the risk of skin shear when moving an occupant between horizontal and upright positions.

Description

CHAIR WITH TELESCOPIC HINGE

This invention relates to a chair for use by infirm or immobile occupants or patients.

The invention relates especially but not exclusively to a chair in which the back and leg portions are pivotally connected for movement relative to the seat in order to allow the chair to be moved into a reclining configuration, particularly in which the back, seated leg form a generally horizontal support.

Preferred embodiments of the invention relate to a seat which may be reconfigured to form a transfer table while occupied by a patient or occupant, for example a bariatric occupant, without requiring manual effort by the occupant or a curer.

A particularly preferred embodiment to the invention permits an occupant to be moved from the chair when in the reclined position to another bed or to another transfer table for bathing, toileting or seating purposes without the need for lifting equipment or manual lifting by nursing assistants.

US-A-4679259 discloses a reclineable wheelchair in which the surface of the wheelchair is an endless belt. A bed having a sheet mounted on head and foot rollers is used to transport a person head or feet first onto the chair.

According to the present invention a seat comprises a frame and seat, back and leg supports, the back and leg supports being moveable between an upright seating configuration and a reclined configuration; wherein the back and seat supports are connected by a pivotal linkage; wherein the seat includes an actuator adapted to move the back support between reclined and upright configurations when carrying an occupant; wherein the linkage comprises a connection between the back and seat supports, the connection between the hinge and seat being extendable so that the distance between the hinge pivot and seat increases as the back moves from a reclined position to an upright position and decreases as the back moves from an upright position to a reclined position.

The hinge may comprise first and second attachments connected by a pivot linkage; the first attachment being connected to the back portion of the chair; and the second attachment being connected by an extensible linkage to the seat portion of the chair; means being provided to extend the linkage as the seat moves from the reclined to the upright configuration and to retract the linkage during the reverse movement.

In a preferred embodiment the back support and seat support are mounted on a frame, the back and seat supports being connected together by the hinge located at a rear edge of the seat support and at a forward edge of the back support.

Preferably the actuator moves both of the back and seat supports between upright and inclined configurations.

The seat support may be pivotally connected to the frame at a forward part of the seat support. Such an arrangement is advantageous in allowing the seat to rotate downwardly from a horizontal location as the seat moves towards the upright position, and further allows the seat to rotate to a horizontal position as the seat is moved into the reclined configuration.

Preferably the seat, back and leg supports are each mounted on a respective endless belt, each endless belt extending in a loop over a plurality of rotatable drive members extending longitudinally of the seat; drive means being adapted to cause rotation of the endless belts so that each support structure moves laterally across the seat whereby an occupant located on the supports may be moved laterally across the seat in use.

In such an embodiment space should be provided beneath the seat support to allow the seat cushion to rotate and be stowed underneath the seat during transfer of an occupant.

A preferred embodiment of the invention facilitates movement of a disabled, immobile, infirm or otherwise physically or mentally incapacitated occupant from the chair to a bed or transfer table for bathing, dressing or toileting without the need for lifting or manual assistance or lifting devices.

The invention further comprises a seat as previously disclosed in combination with a bed as described, for example, in W020l0/010386, W02010/010388 or W02010/0l0387, the disclosures of which are incorporated into the present specification by reference for all purposes.

The seat may ftirther comprise an actuator connected to the back section at a location remote from the hinge, the actuator being further connected to the frame at a location below a horizontal plane in which the hinge is located.

The height and angular orientation of the abutment may be adjustable. The angle of the back section at which retraction of the hinge occurs may be adjusted.

An abutment may be provided to engage a complementary surface of the back support restrain downward rotation of the back support during movement from an upright to a reclined position. Advantageously, such an abutment serves to cause a retraction of the hinge as the actuator pulls on the back support following engagement with the abutment.

The abutment may comprise a moveable support mounted on the frame, the support being moveable from an upper position in which the back support is upright and not in contact with the abutment, to a lower position wherein the back support engages the abutment and causes the moveable support to rotate to maintain engagement as the back support rotates towards the inclined position.

The moveable support may include biasing means, for example a gas spring, to urge the moveable support toward the upper position.

Rollers may be provided on the abutment to facilitate moveable contact with the back support as the hinge extends or retracts.

The back support may include a downwardly facing support surface arranged to abut a complementary upwardly facing contact member of the frame.

In a preferred embodiment a cam surface on a seat back engages a bearing, roller or wheel formation on the frame to raise the location of the hinge as the hinge approaches the fully retracted position. a

Traction gas springs may be provided to assist retraction of the hinge, particularly when the frame is unloaded. This provides a more efficiently balanced operation. The seat may be arranged so that the actuator and gas springs are arranged so that a minimal power consumption is required by the actuator when carrying an occupant.

A chair in accordance with the present invention provides many advantages. The mechanism may be adaptable to suit the weight, height and comfort requirements of an occupant. The height of the abutment may be adjusted so that retraction of the hinge takes phice at a preferred selected angle of the back support.

A further advantage is that retraction or extension of the hinge allows skin shear to be reduced when moving an occupant between the upright and horizontal positions or vice versa due to movement of the supports or extension or retraction of the hinge.

Use of an adjustable hinge prevents trapping or crushing of a patient particularly a bariatric patient at the hinge point when moving to the upright position.

Use of fraction gas springs on the seat section may assist in the retraction of the telescopic hinge.

The moveable support acts as a safety buffer in the event of failure of an actuator, for example in preventing the back from falling down suddenly in the event of a mechanical failure.

The height and angle of the moveable support may be adjusted. The angifiar location at which the hinge extension occurs may be adjusted but one can also adjust the amount of extension of the hinge. The upward force applied by the moveable support may also be adjusted. These adjustments permit the seat to be configured to suit the physique and requirements of a user.

The gas springs may also assist in the final stages of returning the chair to a horizontal or inclined configuration against the weight of an occupant.

The invention is further described by means by example but not in a limitative sense with reference to the accompanying drawings of which:

I

Figure 1 is a perspective view of a chair in accordance with this invention; Figure 2 is a perspective view of the rear of the chair; Figure 3 is side elevation of the chair in the reclined position; Figure 4 is a side elevation of the chair at the first stage of movement from the reclined to the upright position; Figure 5 is a side elevation showing the chair after frirther movement from the reclined to the upright position; Figure 6 shows the chair in the upright position; Figure 7 is a detailed view of the hinge arrangement from the side; Figure 8 is a detailed view of the hinge arrangement from the rear; and Figure 9 is a further detailed view from the rear.

Figures 1 and 2 are perspective views of a chair in accordance with the invention in a partially reclined position. A back support pad (1), seat support pad (2) and leg support pad (3) are mounted on a frame (5) having ground engaging wheels (6). The back support (1) is mounted on a back support frame (4). The back support (1) is moveable transversely upon an endless conveyor (11) mounted on sprockets (12) driven by a chain drive and motor (13). The seat support (2) and leg support (3) are also mounted on endless conveyors (14,15) and are arranged to be moveable transversely, synehronised with the movement of the back support conveyor (11).

During movement from the reclined to the upright position, the leg support (3) rotates downwardly about a hinge on the upper or rear edge so that the support may be stowed underneath the seat. This allows an occupant's feet to rest hanging downwardly in the normal seated position. The seat support (2) may be deployed underneath the conveyor (14) during transfer of an occupant to or from the seat, a space being provided underneath the conveyor to receive the pad (2). Similarly, the back support frame (4) incorporates a space beneath the conveyor (11) to receive the pad during transfer of an occupant.

The back support frame (4) and seat support frame (17) (see Figures 7 & 8) are connected by an extendable hinge. Two hinge pivots (18) (Figure 7) are fixed to the support frame (4). Extendable members (19) extend from the pivot (18) and are slidably received within sockets in the seat support frame (17). The location of the pivot (18) relative to the If seat frame (17) may be increased or decreased by telescopic movement of the members (19) within the seated frame sockets. Traction gas springs (not shown) may be provided within the seat frame to assist in retraction of the hinge towards the seat. Pivots (16) mounted on upwardly extending legs of the frame (5) support the forward edge of the seat, permitting the seat to pivot so that the rear end of the seat may move upwardly or downwardly. Downward movement of the seat cushion (2) as the chair moves into the seated position increases comfort for an occupant. However, the seat returns to a horizontal position in the reclined table transfer position so that a horizontal surface is provided from head to foot.

The seat back is raised or lowered by a battery powered linear actuator (25) secured by a pivotal linkage (26) to an upper part of the back support frame and also coupled by a pivotal linkage (27) to the seat frame (5) at a location below a horizontal plane containing the hinges (19). Two traction (pull) gas springs (28) with adjustable traction force assist the linear actuator (25) in pulling the back frame (4) down and into a filly horizontal position.

Two cradles (20) having rear (21) and front (22) rollers extend upwardly from the frame (5). The cradles (20) are pivotally mounted at a front end and guided by part-circular guides (23). Gas springs (24) provide a restoring force against downward movement of the rollers (21).

Stabiliser arms (23) serve to prevent the frame (4) from twisting under load.

The angle at which the back frame begins to extend out and away from the seat can be adjusted to suit an occupant by altering the stroke and length of the push gas springs (24).

As the seat back moves to the lowered, reclined, position a downwardly facing surface of frame (4) engages rearward rollers (21) and then forward rollers (22). As the actuator (25) is further retracted with additional force provided by an occupant's weight, the front lower end of the frame (4) and back pad (1) are raised by engagement of the frame (4) and curved cam surface (29) against the fixed roller (30) extending upwardly from the frame (5) urging the hinge upwardly and also raising the rear end of the seat frame and pad (2).

The rollers (30) co-operate with the cam surfaces (29) to support the back and seat portions connected by the hinge in the fully horizontal position. In this position, the conveyers are accurately aligned to provide smooth and efficient transfer of an occupant to or from the transfer table configuration.

The cam is preferably arranged so that the seat raises or lowers through about 5 degrees during the process of profiling the chair from the horizontal reclined position to the upright seated position.

Figures 3-6 show various stages in the raising from the reclined to seated position.

In the fully reclined position in Figure 3, the hinge is fully retracted. The telescopic extendable hinge (18,19) begins to extend as the seat reaches the inclined position as shown in Figure 6 and shown in more detail in Figures 7 and 8. When the seat back is lowered, returning to the arrangement shown in Figures 5, 4 and 3, contact between the cam surface (29) and fixed wheel (30) urges the member (19) into the socket in the seat, causing retraction of the hinge so that a continuous surface is provided to receive an occupant.

The degree of extension provided by the hinge may be adjusted by moving the position of a location pin provided in the member (19).

Claims (14)

1. CLAIMS1. A seat comprising a frame and seat, back and leg supports, the back and leg supports being moveable between an upright seating configuration and a reclined configuration; wherein the back and seat supports are connected by a pivotal linkage; wherein the seat includes an actuator adapted to move the back support between reclined and upright configurations when carrying an occupant; wherein the linkage comprises a connection between the back and seat supports, the connection between the hinge and seat being extendable so that the distance between the hinge pivot and seat increases as the back moves from a reclined position to an upright position and decreases as the back moves from an upright position to a reclined position.
2. 2. A seat as claimed in claim 1, wherein the hinge comprises first and second attachments connected by a pivot linkage, the first attachment being connected to the back portion of the chair and the second attachment being connected by an extensible linkage to the seat portion of the chair, means being provided to extend the linkage as the seat moves from the reclined to the upright position and to retract the linkage as the seat moves from the upright to the reclined configuration.
3. 3. A seat as claimed in claim 1 or 2, wherein the back support and seat support are mounted on a frame, the back and seat supports being connected together by the hinge located at a rear edge of the seat support and at a forward edge of the back support.
4. 4. A seat as claimed in claim 3, wherein the seat support is pivotally connected to the frame at a forward part of the seat support.
5. 5. A seat as claimed in any preceding claim, wherein the seat, back and leg supports are each mounted on a respective endless belt, each endless belt extending in a loop over a plurality of rotatable drive members extending longitudinally of the seat; drive means being adapted to cause rotation of the endless belt so that each support structure moves laterally across the seat, whereby an occupant located on the supports may be moved laterally across the seat in use.
6. 6. A seat as claimed in any preceding claim, wherein a space is provided beneath the seat support to allow the seat cushion to rotate and be stowed underneath the seat during transfer of an occupant. a
7. 7. A seat as claimed in any preceding claim, further comprising an actuator connected to the back of the seat section at a location remove from the hinge, the actuator being further connected to the frame at a location below a horizontal plane in which the hinge is located.
8. 8. A seat as claimed in any preceding claim, further comprising an abutment to restrain downward rotation of the back support during movement from an upright to a reclined position.
9. 9. A seat as claimed in claim 8, wherein the abutment comprises a moveable support mounted on the frame, the moveable support being moveable from an upper position in which the back support is upright and not in contact with the abutment and a lower position wherein the back support engages the abutment and causes the support to rotate as the back support rotates towards the inclined position.
10. 10. A seat as claimed in claim 8 or 9, wherein the moveable support includes biasing means to urge the support towards an upper positions.
11. 11. A seat as claimed in any of claims 8 to 10, wherein the height of the abutment isadjustable.
12. 12. A seat as claimed in any of claims 8 to 11, wherein the angle of the back section at which retraction of the hinge commences is adjustable.
13. 13. A seat as claimed in any preceding claim, further comprising traction gas springs to assist retraction of the hinge. F
14. 14. A seat substantially as hereinbefore described with reference to the accompanying drawings. 9. .