Field of the Invention

This invention relates to folding chairs and in particular, though not necessarily solely, to a folding stairlift chair.

Background to the Invention

Chairs may be provided in forms that are capable of being folded for a number of reasons, one principal reason being to reduce the bulk of the chair when not in use. In the particular case of a stairlift chair, comprising a seat base, backrest, armrests and a footrest, it is desirable, when the stairlift is not in use and the seat base, armrests and footrest are folded, that the depth dimension, the distance from the outer extremity of the folded chair to the wall against which the stairlift is mounted, is as small as possible. In that way, the stairlift causes the least possible interference with the use of the staircase by able- bodied persons. It is also desirable that the stairlift, when both in the in-use configuration and the folded configuration, has the least possible visual impact on its surroundings and that what is visible is as aesthetically appealing as possible.

In our published International Patent Application WO2019/197841 we describe a folding stairlift chair in which the seat base is mounted on the chassis via four-element linkages on opposite sides of the chair. Each armrest is pivotally attached to one of the linkage elements on the corresponding side. Whilst the resulting chair provides the benefits sought in that application, the folding mechanism is relatively complex and expensive to manufacture.

Similar problems may arise in other chair applications. It is an object of the invention to provide a folding chair and/or aspects thereof which will go at least some way in addressing the aforementioned problems or requirements; or which will at least provide a novel and useful choice.

Summary of the Invention

Accordingly, in a first aspect, the invention provides a folding chair having a chassis, a seat base having a seating plane; a plurality of links supporting said seat base on said chassis and configured to control displacement of said seat base relative to said chassis between an in-use state and a folded state; a back rest and a pair of armrests, each said armrest comprising an arm contact part which in the in-use state is arranged to provide arm support to a user, and mount part configured to, in the in-use state, support said arm contact part above said seating plane, characterised in that each said mount part is mounted to displace in a fixed configuration with one of said links such that said armrests and said seat base fold simultaneously.

Preferably said seat base has a forward edge and a rear edge relative to said backrest and each of said armrests has a proximal end which, in the in-use state is positioned adjacent to said backrest, and wherein said links are configured to raise said rear edge relative to said backrest and to displace said front edge toward said backrest as said seat base is moved into the folded state.

Preferably said links and said mount parts are further configured so that the arm contact parts of the armrests are displaced toward a vertical position and toward said backrest as said seat base is moved into the folded state.

Preferably said chassis has a mounting plane and wherein the links are configured such that the proximal ends of said arm contact parts are displaced toward the mounting plane as the seat base is moved into the folded state.

Preferably said seat base and said armrests are configured such that, in the folded state, said seating plane faces in a forward direction relative to said backrest, and said arm contact parts are positioned substantially to the rear of said seating plane.

Preferably said seat base has opposed sides and wherein said links form part of a four-element linkage connecting each of said opposed sides to said chassis.

Preferably parts of said seat base and parts of said chassis form elements of each of said four-element linkages.

In an alternative embodiment the linkage includes a single link having outer ends and a mid-point, wherein the outer ends are spaced laterally and longitudinally from the mid-point, the outer ends being pivotally attached to the seat base and the mid-point being pivotally attached to said chassis.

Preferably the mid-point is pivotally attached to the chassis at or adjacent to a rear edge of the chassis.

Preferably said single link is U-shaped when viewed in plan.

Preferably said mount parts include or are fixed to a cross-member pivotally mounted to said chassis, said seat base being pivotally mounted on or with respect to said cross-member.

Preferably, when viewed in side-elevation and in the folded state, surfaces of said seating plane, said chassis and said backrest define a substantially triangular envelope, and wherein said armrests, in the folded state, are substantially located within said envelope.

In a second aspect the invention provides a folding chair comprising a chassis, a seat base having a seating plane; a linkage configured to support said seat base on said chassis and control displacement of said seat base between an in- use state and a folded state; a pair of armrests displaceable between in-use and folded states; and a backrest, wherein said linkage and said seat base are configured such that, when viewed in side elevation in the folded state, said seating plane faces forward relative to said backrest, and said armrests are positioned substantially rearward of said seating plane.

Preferably said armrests are connected to or form part of said linkage and displace between in-use and folded states together with said seat base.

Preferably, when viewed in side elevation and in the folded state, surfaces of said seating plane, said chassis and said backrest define a substantially triangular envelope, and wherein said armrests, in the folded state, are substantially located within said envelope.

Preferably each of said armrests comprises an arm contact part and a mount part, said mount part being positioned substantially parallel to said seating plane when seat base and said armrests are in the folded state.

Preferably said chassis, said seat base and said armrests are connected to, or form parts of, three or four-element linkages.

In a third aspect the invention provides a folding chair comprising a chassis, a seat base; a pair of armrests; and a linkage configured to support said seat base on said chassis and control displacement of said seat base between an in- use state and a folded state; and a backrest, wherein said backrest, said seat base, said armrests and said linkage are configured such that, when viewed in side elevation in the folded state, surfaces of said chassis, said seat base and said backrest define a substantially triangular envelope, and wherein said armrests are contained substantially within said envelope.

Preferably said linkage is further configured to control displacement of said armrests between in-use state and folded state.

In a fourth aspect the invention provides a folding chair comprising a chassis, a seat base having a seating plane; a linkage configured to support said seat base on said chassis and control displacement of said seat base between an in- use state and a folded state; a backrest; and a pair of armrests, said linkage and said seat base being configured such that, when viewed in side elevation in the folded state, said seating plane faces forward relative to said backrest, wherein said chassis has spaced upturned side edges, such that in the in-use state said linkage is contained between said side edges.

Preferably, in the in-use state, the seating plane lies below upper extremities of said side edges.

Preferably said backrest has spaced forward extending side edges.

Preferably the spacing between the side edges of said chassis is substantially the same as the spacing between the side edges of said backrest.

In a fifth aspect the invention provides a folding chair comprising a chassis, a seat base having a seating plane; a linkage configured to support said seat base on said chassis and control displacement of said seat base between an in- use state and a folded state; and a backrest, said linkage and said seat base being configured such that, when viewed in side elevation in the folded state, said seating plane faces forward relative to said backrest, wherein said chassis has laterally spaced upwardly extending side edges and said backrest has forwardly extending side edges, the side edges of said chassis and the side edges of said backrest defining, in combination with said chassis, a volume in which said seat base is contained in both the in-use and folded states.

Preferably the side edges of said chassis have upper extremities, said seating plane lying below said upper extremities when said chair is in the in-use state.

Preferably the side edges of the back rest have inner and outer surfaces and the chair further includes a pair of armrests connected to or forming part of said linkage such that said armrests fold between in-use and folded states together with said seat base, said linkage and said armrests being configured such that, in the folded state, said armrests are positioned adjacent to the outer surfaces of said backrest.

In a sixth aspect the invention provides a stairlift chair comprising any of the embodiments of folding chair as set forth above.

In a seventh aspect the invention provides a stairlift including the stairlift chair as set forth above.

Irrespective of aspect, a folding chair according to the invention may have one or more of the following:

- A chassis, seat base, armrests and links or a linkage system joining the seat base to the chassis and controlling the position of the seat base relative to the chassis. The armrests form part of the linkage system, the relative positions of the armrests and parts of the linkage system being fixed.

- A back rest, preferably a back rest fixed with respect to the chassis.

- The seat base has an upper contact surface and an under surface. The seat base may comprise a frame and an upholstered section covering the frame, the upper contact surface comprising part of the upholstered section.

- The seat base and chassis have spaced side edges, a linkage comprising links connecting each side of the seat base to each side of the chassis. The links may comprise a pair of fore links and a pair of rear links when viewed with respect to the backrest. Both the chassis and the seat base respectively form parts of the linkage.

- One pair of links joining the seat base to the chassis, preferably the rear pair, may be replaced by a single link or bracket that projects laterally and longitudinally from a central point to outer extremities. The central point may be pivotally attached to the chassis while the outer extremities may be pivotally connected to the seat base. The connection to the chassis is preferably at or near the rear edge of the chassis while the connections to the seat base are preferably on the side edges of the seat base forward of the rear edge. The bracket is preferably U-shaped when viewed in plan.

- The forward links and the armrests are preferably connected to, and project from, a common cross member. The armrests are typically further apart on the cross-member, than the links. The armrests are preferably attached to opposite ends of the cross-member.

- Controlled by the linkage the seat base moves between an in-use position and a folded position. When in the folded position and viewed in side elevation, the chair is contained substantially within a triangular envelope. The envelope is preferably defined, in part, by surface parts of the backrest, chassis and seat base.

- In the folded position the upper contact surface of the seat base is visible and the under surface is substantially hidden.

- In the folded position, the armrests lie to the rear of a plane passing along the upper contact surface of the seat base.

- Each armrest has an arm contact part and a mount part, the arm contact part having a proximal end and a distal end relative to the backrest, wherein the proximal end is displaced downwardly toward the plane of the chassis when the chair is displaced to a folded configuration. The arm contact part is preferably angled at around 10 from the horizontal when the chair is in the in- use position.

- The backrest may have spaced forwardly directed side edges and/or the chassis may have spaced, upwardly directed side edges. The upwardly directed side edges of the chassis preferably extend above a plane passing over and in contact with the upper contact surface of the seat base.

- The spacing between the forwardly directed side edges of the backrest is substantially the same as the spacing between the upwardly directed side edges of the chassis.

- When viewed in elevation, the linkage system is preferably contained within the upwardly directed side edges of the chassis.

Many variations in the way the present invention can be performed will present themselves to those skilled in the art. The description which follows is intended as an illustration only of one means of performing the invention and the lack of description of variants or equivalents should not be regarded as limiting. Subject to the scope of the appended claims, wherever possible, a description of a specific element should be deemed to include any and all equivalents thereof whether in existence now or in the future.

Brief Description of the Drawings Various aspects of the invention will now be described with reference to the example shown in the accompanying drawings in which:

Figure 1 : shows a schematic isometric view of a first embodiment of folding stairlift chair incorporating the invention;

Figures 2-4: show, in side elevation, a schematic sequence of steps in the chair of Figure 1 being folded between an in-use state and a folded state;

Figure 5A: shows an isometric view of a second embodiment of folding chair according to the invention in an in-use state;

Figure 5B: shows a side elevational view of that which is shown in Figure 5A;

Figure 5C: shows some structural features of the chair shown in Figures 5A & 5B when in the same state;

Figures 6A: show, respectively, similar views to Figures 5A to 5C but with to 6C the chair in a partly folded state;

Figures 7A: show, respectively, similar views to Figures 5A to 5C but with to 7C the chair in a fully folded state;

Figure 8: shows a schematic view, not to scale, of the folding linkage arrangement included in the chair shown in Figures 5 to 7; and

Figure 9: shows a plan view of one of the linkage components shown in

Figure 8 Detailed Description of Working Embodiments

This invention relates to a folding chair and, more particularly, to a chair that has been developed for application as a stairlift chair. Accordingly, the embodiments described herein will be directed to a stairlift chair but it should be appreciated that other applications of folding chair may fall within the scope of the invention.

In a first embodiment a chair 10 according to the invention includes a chassis

11, a seat base 12, a backrest 13 and a pair of armrests 14. It will be appreciated that, in the case of a stairlift chair, there will also be suitable attachments whereby the chair can be mounted on a stairlift carriage but, since the mounting to the carriage does not form part of the invention, it will not be described. Those skilled in the field of stairlifts will also understand that an operating control is typically provided on one of the armrests 14 but, again, since the nature and placement of the operating control does not form part of the invention, it will not be shown or described herein.

The seat base 12, which regardless of embodiment, typically comprises an upholstered frame, is supported on the chassis 11 by pairs of linkages 15 (Fig 3), the pairs being on opposite sides of the chair. The linkages are configured to not only fix the seat base to the chassis but also guide and control the movement of the seat base between an in-use state shown in Figure 2 and a folded state shown in Figure 4. An important feature of the linkages 15 is that each of the armrests 14, or an extension of each armrest, is fixed to, or fixed with respect to an element of each of the linkages. This not only simplifies the assembly but also simplifies the folding of the armrests 14 with the seat base

12. In this regard, the armrests may be linear extensions of two of the link elements or may be rigidly fixed to a cross member to which two of link elements are also rigidly fixed. In the case of the latter, the armrests will preferably be mounted to the outside of the linkages and, more preferably, to the outer ends of the cross-member.

While those skilled in the art can envisage many alternative configurations of linkage, in this embodiment the linkage comprises a pair of four-element linkages connecting the sides 16 of the seat base 12 to side parts of the chassis 11, one pair, on one side of chair, being shown. Each four-element linkage is provided in part by the seat base and by the chassis, and completed by two pivoting links which connect the seat base to the chassis. The various elements of each linkage are connected by pivots 22a, 22b, 22c & 22d. Part 19 of the seat base between pivots 22b & 22c comprises one element of the linkage while part 20 of the chassis comprises another element. Pivoting links 18 between pivots 22c & 22d; and 21 between pivots 22a & 22b, complete each linkage. Those skilled in the art will appreciate that the lengths of the four respective elements 18, 19, 20 & 21, and the positions of the pivots 22a, 22b, 22c & 22d, are selected to achieve the particular desired folding geometry.

The seat base 12 has a forward edge 24 and a rear edge 25 relative to the backrest 13, and the mounting assembly or linkage arrangement is preferably configured so that, as the seat base 12 is displaced from the in-use state to the folded state, the rear edge 25 rises and the forward edge 24 is displaced rearwardly. This ensures that the upper or upholstered surface of the seat base is visible and the less visually attractive seat underside is substantially hidden.

As stated above, an important aspect of the invention is that each armrest is fixed in configuration with respect to one element of the four-element linkage. In this example each armrest is fixed with respect to one of the pivoting links 18 or 21, and preferably with respect to the forward link element 18.

In this particular embodiment, each armrest 14 comprises an angled bracket that may be preferably cast or otherwise formed from a metal and, more preferably, from aluminium. The two armrests 14 are preferably identical, each comprising an arm contact part 26 which, in the in-use position, is configured and arranged to support a user’s forearm. Typically, the arm contact part 26 is horizontal or near horizontal, for example within 10° of horizontal. The arm contact part has a proximal end 28 adjacent to the backrest 13 when in the in-use state, the contact part 26 merging into a downwardly extending mount part 29 at apex 30.

The downwardly extending mount part 29 may be formed integrally with the link element 18 or rigidly attached to the link element 18. As a further alternative, the downwardly extending mount parts 29 and the link elements 18 may be rigidly attached to, and project from, a common cross-member (not shown) that is positioned across the chair, concentrically with pivot 22c, and in substantially the same manner as shown in Figs 6c & 7c, the seat base 112 being rotatable on the cross-member. In those embodiments in which the downwardly extending mount part is formed integrally with the link element 18, a suitably angled joint may be provided as shown at 31 to configure the linkage and armrest in an overall sense to achieve the required folded configuration. The same effect can be achieved by positioning the link elements 18 and downwardly extending mount parts 29 at appropriate spaced positions on the cross-member.

Another particularly preferred feature of this embodiment is that, when in the folded state, and when viewed in side elevation, as in Figure 4, the armrests 14, and preferably the chair as a whole, are substantially contained in a triangular envelope 32 shown in dotted outline, boundaries of the envelope being defined substantially by the surface parts of the chassis 11, the seat base 12 and the backrest 13. In the folded state it can be seen that the proximal ends 28 of the arm contact parts 26 are positioned closely adjacent to the base 33 of the envelope, being the plane of the underside of chassis 20; while the armrests 14 lie behind the boundary 34 passing across the seating plane of the seat base, the downwardly extending mount parts 29 of the armrests being positioned substantially parallel to the boundary 34 but behind the seating plane of the seat base 12. In this state the apex 30 of the armrest lies below the level of the rear edge 25 of the seat base. This folded state not only ensures a compact form but also a form that concentrates the eye on the upper surface of the seat base and minimises the visual intrusion of the chair as a whole.

Referring now to Figures 5 to 9, a second embodiment 40 of folding stairlift chair is shown. As with the previous embodiment some features of the chair, such as the chair mounting and user control, is not described as these features do not form part of the invention. The main emphasis, as before, lies in the folding arrangement although other novel aspects will also become apparent from the description below.

This embodiment of chair includes a chassis 41, a seat base 42, a backrest 43 and a pair of armrests 44. The seat base 42 is supported on the chassis 41 by a linkage 45, the linkage being configured to not only fix the seat base to the chassis but also guide and control the movement of the seat base between an in-use state shown in Figure 5 and a folded state shown in Figure 7. An important feature of this linkage 45, as with the embodiment described above, is that the armrests 44, or extensions of the armrests, are rigidly attached to parts of the linkage which not only simplifies the assembly but also ensures that the armrests 44 fold with the seat base 42. A particular feature of this embodiment is that one pair of links of the pair of four-element linkages of the previously described embodiment are replaced by a single bracket. More particularly, preferably the two rear most links 21 of the previously described embodiment are replaced by a single bracket 46 having outer ends 47 and a mid-point 48, the outer ends being laterally and longitudinally spaced from the mid-point 48. Conveniently but by no means essentially, the bracket is U-shaped. The outer ends 47 are pivotally attached to the seat base 42, or to a bracket attached to the seat base, while the midpoint 48 is pivotally attached to the chassis at a point 49 on or adjacent to the rear edge of the chassis.

As with the embodiment described above, the backrest 43 is preferably fixed with respect to the chassis 41.

The seat base 42 has a seating plane 50, a forward edge 51 and a rear edge 52 relative to the backrest 43 and, as with the embodiment described above, the linkage 45 is preferably configured so that, as the seat base 42 is displaced from the in-use state shown in Figure 5 to the folded state shown in Figure 7, the rear edge 52 rises and the forward edge 51 is displaced rearwardly. This ensures that the seating plane 50, being the upper or upholstered surface of the chair, is visible when the chair is folded and the less visually attractive seat underside is hidden.

In this particular embodiment, the armrests 44 each comprise an arm contact part 53 which, in the in-use state, is configured and arranged to support a user’s forearm. Typically, the arm contact part 53, in the in-use state, is horizontal or near horizontal, for example within 10° of horizontal although this figure should not be regarded as limiting. The arm contact part 53 has a proximal end 54 closest to the backrest 43 when in the in-use state and each arm contact part is located at an upper end of a downwardly extending mount part 55, the two mount parts 55 being joined at their lower ends by a cross-member 56. As can be seen more clearly in Figures 8 & 9, the mount parts 55 and cross-member 56 provide, in essence, a unitary assembly, the seat base 42 being mounted on the cross-member 56 by brackets 57 or the like so that the seat base 42 can pivot about the cross-member 56 as the chair is moved between the in-use and folded states. Projecting in a rigid manner from the cross-member 56 are a pair of links 58, the cross-member 56 providing a rigid connection between the mount parts 55 and the links 58. Thus, the linkage 45 comprises U-shaped link 46, the mid-point 48 of which is pivotally attached to the chassis 41 via pivot 49; and the spaced outer ends 47 of which are attached to the underside of seat base 42 via spaced pivots 59; and links 58 attached to the chassis 41 via pivots 60 and to the seat base 42 via cross member 56 pivotally attached to the underside of seat base 42. The remaining elements of the linkage 45 are provided by a section of the chassis between pivot 49 and pivots 60; and sections of the seat base between pivots 59 and the cross-member 56.

As with the embodiment previously described, another particularly preferred feature of this embodiment is that, when in the folded state and viewed in side elevation as in Figure 7B, the folded chair is substantially contained in a triangular envelope 61 shown in dotted outline, boundaries of which are broadly defined by the surfaces of the chassis 41, the seat base 42 and the backrest 43. In this state it can be seen that the armrests 44 lie substantially behind the seating plane 50 of the seat base, the proximal ends 54 of the arm contact parts 53 being displaced rearwardly and down while the downwardly extending mount parts 55 of the armrests are positioned substantially parallel to the seating plane 50. This arrangement, too, concentrates the eye on the seating plane or upper surface of the seat base and minimises the visual intrusion of the armrests and the chair as a whole. Figures 5 to 7 show further features of a folding chair according to the invention that could also be applied to the embodiment shown in Figures 1 to 4. As can be seen chassis 41 has spaced upwardly extending side edges 65 between which the seat base 42 and linkage 45 are received. The side edges preferably extend upwards by such an amount as to ensure that the seating plane 50 lies below the upper extremities 66 of the side edges 65. The backrest preferably further includes spaced forwardly extending side edges 67, the side edges 65 and 67 preferably being spaced apart by substantially the same distance so as to define, in combination with the chassis 41, an open volume into which the seat base 42 and linkage 45 are received in both the in- use and folded positions; although it can be seen that, in this example, the armrests in the folded state lie adjacent to the outer surfaces of the side edges 67 of the backrest. The resulting volume provided by the side edges 65 and 67 also partially encloses a user and is believed to provide an enhanced feeling of security as well as enhancing the overall aesthetics of the chair.

It will thus be appreciated that the invention, at least in the case of the embodiment depicted and described, provides examples of a folding chair particularly suited for application as a stairlift chair which combines a relatively simple folding mechanism which makes full use of the seat base and armrests and which provides an attractive folded appearance.