GB2618816A

GB2618816A - Chair

Info

Publication number: GB2618816A
Application number: GB2207271.4A
Authority: GB
Inventors: Tierney Martin
Original assignee: Phoenix James Ltd
Current assignee: Phoenix James Ltd
Priority date: 2022-05-18
Filing date: 2022-05-18
Publication date: 2023-11-22
Anticipated expiration: 2042-05-18
Also published as: GB202207271D0; GB2618816B

Abstract

A chair comprising a seat base, a seat back and a leg rest assembly. The leg rest assembly has a footrest 12 and is coupled to the seat base to permit pivotal adjustment of the leg rest assembly with respect to the seat base. An actuator 18 acting against the leg rest assembly and the seat base can adjust the angle of the leg rest. One end of the actuator 18 engages a guide slot 24 associated with the leg rest assembly to permit upward pivotal movement of the leg rest assembly without operation of the actuator should the foot plate 12 of the leg rest assembly contact the ground. The guide slot 24 may have first and second portions at an obtuse angle. A linear actuator which can extend may be used. The chair is designed as a therapeutic chair for use in a healthcare setting to help with postural support and pressure management.

Description

FIELD OF THE INVENTION

This invention relates to a chair, and in particular to a therapeutic chair suitable for healthcare use by adults and children with limited mobility and/or other health problems requiring advanced postural support, pressure management and enhanced comfort with increased safety.

113 BACKGROUND OF THE INVENTION

A chair is often considered furniture, but for those that spend a great deal of time sitting or in bed, a chair is a life-saving clinical aid. It can be argued that incorrect use of inappropriate seating has led to an increase in pressure injury incidence, preventable falls and has a detrimental effect on a persons' mobility. Many people who suffer from long term disabilities, who are elderly or lack mobility spend long periods of time sitting. Many chairs do not incorporate the necessary features for pressure management in seating. These include being able to adjust the chair to a person's individual size, provide postural support, repositioning for weight redistribution and appropriate cushion use.

It is known to provide therapeutic chairs specifically designed for healthcare applications which provide enhanced support and a much greater range of adjustability. Of particular importance is the provision of a foot plate upon which the user can place their feet when sitting. The ability to transfer weight to the user's feet when sitting is important for the patient's comfort and stability in the chair. Typically, such chairs provide adjustment for seat depth (distance between the front of the seat cushion and the backrest), angle of the seat back and foot plate and overall angle of tilt of the seat base and seat back (known as "tilt in space"). This tilt in space adjustment can vary between a posterior (rearward or reclined) tilt of to an anterior (forward) tilt to help the use to stand. However, such known chairs tend to be very expensive, heavy, complex and difficult to clean and great care must be taken in the adjustment of the chair to ensure that it remains stable and safe in all positions of adjustment. A particular area of concern is impact of the foot plate with the ground during an anterior tilt, which could tip the chair.

An object of the present invention is to provide a chair suitable for healthcare use 5 which overcomes these problems.

SUMMARY OF THE INVENTION

According to the present invention there is provided a chair comprising a seat base, a seat back mounted on the seat base and a leg rest assembly, said leg rest assembly including a foot plate upon which the user can rest their feet, said leg rest assembly being coupled to the seat base to permit pivotal adjustment the angle of the leg rest assembly with respect to the seat base, an actuator acting against the leg rest assembly and the seat base for adjusting the angle of the leg rest assembly with respect to the seat base, wherein one end of said actuator engages a guide slot associated with the leg rest assembly, said guide slot permitting upward pivotal movement of the leg rest assembly with respect to the seat base without operation of the actuator should the foot plate of the leg rest assembly contact the ground.

Preferably the seat base is pivotally mounted on a support frame to permit adjustment of the angle of the seat base with respect to the support frame, wherein said guide slot is adapted to permit upward pivotal movement of the leg rest assembly with respect to the seat base without operation of the actuator should the foot plate of the leg rest assembly contact the ground during pivotal movement of the seat base with respect to the support frame.

In a preferred embodiment the guide slot includes a first portion, at a lower end of which a pivot member of said actuator rests during normal operation of the actuator to adjust the angle leg rest assembly with respect to the seat base, and a second portion extending rearwardly from an upper end of said first portion, said first and second portions extending at an obtuse angle to one another.

Preferably said actuator comprises a linear actuator.

In one embodiment the leg rest assembly may be pivotally coupled to the seat base, said guide slot being provided on the foot rest assembly.

In an alternative embodiment the leg rest assembly may be coupled to the seat 5 base via a linkage assembly comprising an arrangement of linkage members extending between the seat base and leg rest assembly, said actuator acting between the seat base and said linkage assembly and said guide slot being provided on said linkage assembly. Preferably said linkage assembly facilitates adjustment of the angle of the leg rest assembly with respect to the seat base by 10 extension and retraction of the actuator.

In one embodiment said linkage assembly may comprise a first linkage member having a first end and a second end, the first end of the first linkage member being pivotally coupled to the seat base at a first location thereon; a second linkage member having a first end and a second end, the first end of the second linkage member being pivotally coupled to the seat base at a second location on the sat base, rearwardly spaced from said first location on the seat base; a third linkage member having a first end and a second end, the first end of the third linkage member being pivotally coupled to the leg rest assembly at a first location thereon, the second end of the third linkage member being pivotally coupled to the second end of the second linkage member, the third linkage member being pivotally coupled to the first linkage member at a location between the first and second ends of the first linkage member and between the first and second ends of the third linkage member; a fourth linkage member having a first and a second end, the first end of the fourth linkage member being pivotally coupled to the leg rest assembly at a second location thereon spaced from and below said first location on the leg rest assembly, the second end of the fourth linkage member being pivotally coupled to the second end of the first linkage member. Preferably said guide slot is provided on said first linkage member at a location between the first and second ends thereof.

The first portion of the guide slot may extend at an angle of less than 30° to a line extending between the first and second ends of the first linkage member, said second portion of the guide slot extending at an angle of at least 600 to said line extending between the first and second ends of the first linkage member. The first portion of the guide slot may extends at an angle of less than 150 to a line extending between the first and second ends of the first linkage member, said second portion of the guide slot extending at an angle of at least 75° to said line extending between the first and second ends of the first linkage member. The first portion of the guide slot may be substantially aligned with a line extending between the first and second ends of the first linkage member, said second portion of the guide slot extending substantially transverse to said line extending between the first and second ends of the first linkage member.

BRIEF DESCRIPTION OF THE DRAWINGS

A chair in accordance with an embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-Figure 1 is a perspective view of a chair in accordance with an embodiment of the present invention; Figure 2 is a perspective view of a chair of Figure 1 from the rear; Figure 3 is a detailed view of the underside of the chair of Figure 1; and Figures 4 to 6 are detailed side views through the chair of Figure 1 with parts omitted for clarity.

DETAILED DESCRIPTION OF THE DRAWINGS

As illustrated in the drawings, a chair in accordance with an embodiment of the present invention comprises a support frame 2 mounted upon ground engaging castor wheels 4 for mobility, a seat base 6 pivotally mounted on the support frame 2 to permit adjustment of the angle of the seat base 2 with respect to the support frame 2, a seat back 8 pivotally mounted on the seat base 6 to permit adjustment of the angle of the seat back 8 with respect to the seat base 6 and a leg rest assembly 10 including a foot plate 12 upon which the user can rest their feet, said leg rest assembly 10 being coupled to the seat base 6 to permit adjustment of the angle of the leg rest assembly 10 with respect to the seat base 6.

A first linear actuator 14 extends between the support frame 2 and the seat base 6 5 for facilitating adjustment of the angle of the seat base 6 with respect to the support frame 2 and retention of the seat base 6 at a selected angle with respect to the support frame 2. The first linear actuator 14 facilitates adjustment of the angle of the seat base 6 (as well as the seat back 8 and leg rest assembly 10) with respect to the base frame 2 (and with respect to the horizontal) by extension and retraction 10 of the first linear actuator 14, thereby providing a "tilt in space" function. Preferably the first linear actuator 14 is adapted to provide a tilt in space function between a posterior tilt of up to 45° to the horizontal (with respect to the seat base 6) and an anterior tilt of up to 10° to help a user to stand from a seated position in the chair.

A second linear actuator 16 extends between the seat base 6 and the seat back 8 for facilitating adjustment of the angle of recline of the seat back 8 with respect to the seat base 6 and retention of the seat back 8 at a selected angle with respect to the seat base 6 (for example between 90° and 130° to the seat base 6). The second linear actuator 16 facilitates adjustment of the angle of the seat back 8 with respect to the seat base 6 by extension and retraction of the second linear actuator 16.

A third linear actuator 18 acts between the seat base 6 and the leg rest assembly 10 for facilitating adjustment of the angle of elevation of the leg rest assembly 10 with respect to the seat base 6 and retention of the leg rest assembly 10 at a selected angle with respect to the seat base 6. The third linear actuator 20 facilitates adjustment of the angle of the leg rest assembly 10 with respect to the seat base 6 by extension and retraction thereof.

One or more of the first, second and third linear actuators 14,16,18 may incorporate biasing means, such as a spring or gas pressure, to bias the respective adjustable length linkage member towards an extended position to facilitate adjustment of the chair, and locking means for retaining the linkage member at a desired length. Alternatively, or additionally, one or more of the first, second and third linear actuators 14,16,18 may be powered or driven, for example by means of an electric motor and gearing or may comprise a hydraulic or pneumatic rams, to extend and retract the respective linear actuator 14,16,18 under the control of a suitable control device.

The foot plate 12 extends outwardly from a lower end of a body of the leg rest assembly 10 for supporting a user's feet thereon when seated in the chair. Preferably the distance between the seat base 6 and the foot plate 12 is adjustable to suit the length of the user's legs, for example by mounting the foot plate 12 to 112 said body of the leg rest assembly 10 on a sliding coupling 22 shown in Figures 4 to 6.

The angle of the foot plate 12 with respect to the body of the leg rest assembly 10 may be adjustable to adjust the angle of the user's ankles when their feet are supported on the foot plate 12. In one embodiment such angle adjustment may be provided by an adjustable stop delimiting the rest position of the foot plate 12 with respect to the body of the leg rest assembly 10, for example to give an ankle angle of 75°, 90° or 105° to the body of the leg rest assembly 10. Preferably the foot plate 12 can be folded upwardly to an upright out of use position when required, wherein the foot plate 12 lies flat against the body of the leg rest assembly 10.

In the embodiment shown in the drawings, the leg rest assembly 10 is coupled to the seat base 6 via a linkage assembly 20 comprising an arrangement of linkage members, the third linear actuator 18 being coupled to the linkage assembly 20 of the leg rest assembly 10 via a slotted coupling arrangement which provides enhanced stability and safety by permitting upward tilting of the leg rest assembly 10 should the foot plate 12 contact the ground during adjustment of movement of the chair. The third linear actuator 18 is pivotally coupled to the seat base at a first end thereof and is slidingly engaged with a guide slot 24 associated with the leg rest linkage assembly 20 at a second end 19 thereof, opposite said first end.

Preferably the guide slot 24 includes a downwardly and forwardly facing end portion 26, at a bottom of which a pivot member of said second end 19 of the third linear actuator 18 rests during normal operation of the chair, and a rearwardly extending portion 28, extending rearwardly from an upper end of said end portion 26. In normal use, the pivot member of the second end 19 of the third linear actuator 18 rests against the bottom of said end portion 26 of the guide slot 24, transferring the weight of the leg rest assembly 10, and any load applied thereto, to the seat base 6, via the third linear actuator 18.

When the first linear actuator 14 is extended in tilt to tilt the seat base 6 forwardly with respect to the support frame 2 during a tilt in space operation, for example to bring the seat to an anterior tilt to assist a seated user to stand, there is a risk of the foot plate 12 striking the ground, potentially lifting the support frame 2 of the chair and creating an unstable and potentially dangerous situation, particularly where the distance between the foot plate 12 and the seat base 6 is at or close to a maximum to suit taller patients. The slotted coupling between the second end 19 of the third linear actuator 18 and the linkage assembly 20 of leg rest assembly 10 prevents this from happening, as will be described below.

Should the foot plate 12 contact the floor during anterior tilt of the seat base 6 with respect to the support frame 2, the pivot member of said second end 19 of the third linear actuator 18 will be lifted out of the end portion 26 of guide slot 24 and is able to move along the rearward portion 28 of the guide slot 24, thereby permitting the leg rest assembly 10 to pivot forwardly and upwardly with respect to the seat base 2. The pivot member of said second end 19 of the third linear actuator 18 will slide back to the bottom of the end portion 26 of the guide slot 24 under the weight of the leg rest assembly 10 once chair is adjusted or moved to a configuration where the foot plate 12 no longer engages the ground.

As shown in Figure 3, the guide slot 24 within which the second end 19 of the third linear actuator 18 slides may comprise a pair of aligned slots 24 formed in side plates 31A,32B of a mounting bracket 30, the second end 19 of the third linear actuator 18 being located between said side plates 32A,32B of the mounting bracket 30 with a bolt 34 passing through the second end 19 of the third linear actuator 18 and said aligned guide slots 24.

In the embodiment shown in the drawings, the linkage assembly 20 coupling the leg rest assembly 10 to the seat base 6 comprises a first linkage member 34 having a first end and a second end, the first end of the first linkage member 34 being pivotally coupled to the seat base 6 at a first location thereon "A"; a second linkage member 36 having a first end and a second end, the first end of the second linkage 36 member being pivotally coupled to the seat base 6 at a second location "B" on the seat base 6, rearwardly spaced from said first location "A" on the seat base 6; a third linkage member 38 having a first end and a second end, the first end of the third linkage member 38 being pivotally coupled to the leg rest assembly at a first location "C" thereon, the second end of the third linkage member 38 being pivotally coupled to the second end of the second linkage member 36, the third linkage member 38 being pivotally coupled to the first linkage member 34 at a location between the first and second ends of the first linkage member 34 and between the first and second ends of the third linkage member 38; a fourth linkage member 40 having a first and a second end, the first end of the fourth linkage member 40 being pivotally coupled to the leg rest assembly 10 at a second location "D" thereon spaced from and below said first location "C" on the leg rest assembly 10, the second end of the fourth linkage member 40 being pivotally coupled to the second end of the first linkage member 34. The guide slot 24 may be provided on said first linkage member 34 at a location between the first and second ends thereof.

Preferably the first portion of the guide slot extends at an angle of less than 30° to a line extending between the first and second ends of the first linkage member, said second portion of the guide slot extending at an angle of at least 60° to said line extending between the first and second ends of the first linkage member. More preferably the first portion of the guide slot is extends at an angle of less than 150 to a line extending between the first and second ends of the first linkage member, said second portion of the guide slot extending at an angle of at least 75° to said line extending between the first and second ends of the first linkage member. The first portion of the guide slot may be substantially aligned with a line extending between the first and second ends of the first linkage member, said second portion of the guide slot extending substantially transverse to said line extending between the first and second ends of the first linkage member. The angular relationship of the first and second pads of the guide slot with respect to one another and with respect to the first linkage member ensures that the pivot member of the second end 19 of the third linear actuator 18 will be readily lifted out of the end portion 26 of guide slot 24 and is able to move along the rearward portion 28 of the guide slot 24, thereby permitting the leg rest assembly 10 to pivot forwardly and upwardly with respect to the seat base 2 should the foot plate 12 contact the floor during anterior tilt of the seat base 6 with respect to the support frame 2 (i.e. when the first linear actuator 14 is extended in tilt to tilt the seat base 6 forwardly with respect to the support frame 2 during a tilt in space operation), while also permitting the leg rest assembly to be moved into an angle of less than 90° to the seat base upon retraction of the third linear actuator 18 to pull the leg rest assembly 10 back into a negative angle with respect to the vertical. To achieve this the end portion 26 of the guide slot is arranged to slope downwardly and towards the rear of the chair once the leg rest assembly moves past the vertical axis into negative angle such that further retraction of the third linear actuator pulls its second end tighter into said end portion 26 of the guide slot 24, preventing the pivot member of said second end 19 of the third linear actuator 18 from sliding along the guide slot 24 away from said end portion 26, as can be seen from Figure 4.

In an alternative embodiment, not shown, the leg rest assembly may be pivotally coupled to the seat base, either with or without an intervening linkage assembly, and the guide slot may be provided on a portion of the leg rest assembly 10 such that the third linear actuator acts directly between the seat base and leg rest assembly.

The invention is not limited to the embodiment described herein but can be amended or modified without departing from the scope of the present invention as defined by the appended claims.

Claims

CLAIMS1. A chair comprising a seat base, a seat back mounted on the seat base and a leg rest assembly, said leg rest assembly including a foot plate upon which the user can 5 rest their feet, said leg rest assembly being coupled to the seat base to permit pivotal adjustment the angle of the leg rest assembly with respect to the seat base, an actuator acting against the leg rest assembly and the seat base for adjusting the angle of the leg rest assembly with respect to the seat base, wherein one end of said actuator engages a guide slot associated with the leg rest assembly, said guide 10 slot permitting upward pivotal movement of the leg rest assembly with respect to the seat base without operation of the actuator should the foot plate of the leg rest assembly contact the ground.
2. A chair as claimed in claim 1, wherein the seat base is pivotally mounted on a support frame to permit adjustment of the angle of the seat base with respect to the support frame, wherein said guide slot is adapted to permit upward pivotal movement of the leg rest assembly with respect to the seat base without operation of the actuator should the foot plate of the leg rest assembly contact the ground during pivotal movement of the seat base with respect to the support frame.
3. A chair as claimed in any preceding claim, wherein the guide slot includes a first portion, at a lower end of which a pivot member of said actuator rests during normal operation of the actuator to adjust the angle leg rest assembly with respect to the seat base, and a second portion extending rearwardly from an upper end of said first portion, said first and second portions extending at an obtuse angle to one another.
4. A chair as claimed in any preceding claim, wherein said actuator comprises a linear actuator.
5. A chair as claimed in any of claims 1 to 4, wherein the leg rest assembly is pivotally coupled to the seat base, said guide slot being provided on the foot rest assembly.
6. A chair as claimed in any of claims 1 to 4, wherein the leg rest assembly is coupled to the seat base via a linkage assembly comprising an arrangement of linkage members extending between the seat base and leg rest assembly, said actuator acting between the seat base and said linkage assembly and said guide 5 slot being provided on said linkage assembly.
7. A chair as claimed in claim 6, wherein said linkage assembly facilitates adjustment of the angle of the leg rest assembly with respect to the seat base by extension and retraction of the actuator.
8. A chair as claimed in claim 7, wherein said linkage assembly comprises a first linkage member having a first end and a second end, the first end of the first linkage member being pivotally coupled to the seat base at a first location thereon; a second linkage member having a first end and a second end, the first end of the second linkage member being pivotally coupled to the seat base at a second location on the seat base, rearwardly spaced from said first location on the seat base; a third linkage member having a first end and a second end, the first end of the third linkage member being pivotally coupled to the leg rest assembly at a first location thereon, the second end of the third linkage member being pivotally coupled to the second end of the second linkage member, the third linkage member being pivotally coupled to the first linkage member at a location between the first and second ends of the first linkage member and between the first and second ends of the third linkage member; a fourth linkage member having a first and a second end, the first end of the fourth linkage member being pivotally coupled to the leg rest assembly at a second location thereon spaced from and below said first location on the leg rest assembly, the second end of the fourth linkage member being pivotally coupled to the second end of the first linkage member.
9. A chair as claimed in claim 8, wherein said guide slot is provided on said first 30 linkage member at a location between the first and second ends thereof.
10. A chair as claimed in claim 9 when dependent upon claim 3, wherein the first portion of the guide slot extends at an angle of less than 300 to a line extending between the first and second ends of the first linkage member, said second portion of the guide slot extending at an angle of at least 60° to said line extending between the first and second ends of the first linkage member.
11. A chair as claimed in claim 9, when dependent upon claim 3, wherein the first portion of the guide slot is extends at an angle of less than 15° to a line extending between the first and second ends of the first linkage member, said second portion of the guide slot extending at an angle of at least 75° to said line extending between the first and second ends of the first linkage member.
12. A chair as claimed in claim 9, when dependent upon claim 3, wherein the first portion of the guide slot is substantially aligned with a line extending between the first and second ends of the first linkage member, said second portion of the guide slot extending substantially transverse to said line extending between the first and second ends of the first linkage member.