A chair with a backrest recline mechanism

Abstract

The invention relates to chair (eg a wheelchair (1)), comprising a seat (2), backrest (3), and backrest adjuster (4). The backrest adjuster incorporates a locking mount (7), a backrest mount (5), a notched catch (6) having a selection of notches (11) each adapted to engage with the locking mount (7), and a lever (13). The recline adjuster is able to lock the backrest in a recline position where a first of the notches is engaged with the locking mount (7). Further, pivoting the lever (13) causes the catch (6) to disengage with the locking mount (7) to enable the catch (6) to move forwards or backwards with respect to the locking mount (7). This causes the backrest mount (5) to pivot about connection (9), and also to pivot about connection (8), to adjust the backrest's recline angle. The backrest is releasably locked by a second one of the notches.

Description

[0001] TITLE

[0002] A Chair with a Backrest Recline Mechanism

[0003] FIELD OF INVENTION

[0004] This invention relates to a chair having a backrest recline mechanism, preferably but not necessarily in the form of a wheelchair.

[0005] BACKGROUND

[0006] Backrest recline mechanisms are well-known and are often used in wheelchairs to accommodate a relaxed at-rest posture for a user. Most backrest recline mechanisms are cable operated with struts on the backrest frame and are such that the angle of the backrest can be adjusted by operation of a handle. A common problem with such mechanisms is that the backrest can too easily move out of the recline position it is adjustably set to due to the cable slipping or stretching. Also, such mechanisms can take up an inordinate amount of space on the wheelchair frame and therefore leave insufficient room for retrofitting aftermarket backrest features or accessories.

[0007] OBJECT OF THE INVENTION

[0008] It is an object of preferred embodiments of the invention to go at least some way towards addressing one or more of the above problems. While this applies to preferred embodiments, it should be understood that the object of the invention in its broadest form is simply to provide a useful choice. Therefore, any objects, benefits or advantages of any preferred embodiment should not be inferred as limitations on the scope of the invention per se.

[0009] DEFINITIONS

[0010] The term “comprising” when used in this specification in relation to a feature or a combination of features indicates the presence of the named feature(s) but does not rule out the option of there being an additional feature or features that have not been mentioned.

[0011] SUMMARY OF THE INVENTION

[0012] According to one aspect, the invention is a chair comprising:

[0013] • a seat;

[0014] • a backrest; and • a backrest adjuster comprising a set of: o a locking mount; o a backrest mount; o a notched catch having a selection of notches each adapted to engage with the locking mount in turn; and o a lever (eg a pedal); the adjuster being formed such that:

[0015] • it is able to lock the backrest in a recline position in which a first one of the notches is engaged with the locking mount; and

[0016] • pivoting the lever causes the catch to raise and disengage with the locking mount to enable the catch to move forwards or backwards with respect to the locking mount such that the backrest mount pivots about a connection to the notched catch and also pivots about a connection to the locking mount to adjust the recline angle of the backrest and be locked in that position by engagement of a second one of the notches with the locking mount.

[0017] Optionally the lever is pivotally connected to the locking mount.

[0018] Optionally the notched catch has a guide pin adapted to slide along a guide slot in the lever as the catch moves with respect to locking mount.

[0019] Optionally the locking mount comprises a pin adapted to engage with the notches respectively to in each case lock the backrest in one of the recline positions.

[0020] Optionally the locking mount is rigidly fixed so that it is unable to move, but wherein the backrest mount, the notched catch and the lever can move with respect to it.

[0021] Optionally a spring which acts between the locking mount and the notched catch to spring bias the notched catch downwards to engage with the locking mount, but such that downward movement of the lever overcomes the spring bias.

[0022] Optionally the backrest mount is secured to a side bar of a frame of the chair.

[0023] Optionally each backrest mount comprises a pair of plates arranged in parallel alignment. Optionally the backrest adjuster has a second set of each of the backrest mount, the locking mount and the notched catch arranged in similar relationship to one another as the first mentioned set and being disposed at an opposite side of the chair, the first and second mentioned sets being connected by a cross-shaft adapted to transfer recline adjustment force from one side of the chair to the other.

[0024] Optionally the chair is in the form of a wheelchair.

[0025] Optionally the chair is such that: a) the lever is pivotally connected to the locking mount; b) the notched catch has a guide pin adapted to slide along a guide slot in the lever as the catch moves with respect to locking mount; c) the locking mount comprises a pin adapted to engage with the notches respectively to in each case lock the backrest in one of the recline positions; d) the locking mount is rigidly fixed so that it is unable to move, but wherein the backrest mount, the notched catch and the lever can move with respect to it; and e) there is a spring which acts between the locking mount and the catch to spring-bias the catch downwards to engage with the locking mount but such that downward movement of the lever overcomes the spring bias.

[0026] For the embodiment immediately above, optionally the backrest adjuster has a second set of each of the backrest mount, the locking mount and the notched catch arranged in similar relationship to one another as the first mentioned set and being disposed at an opposite side of the chair, the first and second mentioned sets being connected by a cross-shaft adapted to transfer recline adjustment force from one side of the chair to the other.

[0027] For the embodiment immediately above, optionally the chair is a wheelchair.

[0028] DRAWINGS

[0029] Some preferred embodiments of the invention will now be described with reference to the accompanying drawings, of which:

[0030] Figure 1 is an isometric view of wheelchair comprising a backrest incline adjuster; Figure 2 is an isometric view of the wheelchair ghosted, except for the incline adjuster;

[0031] Figure 3 is an isometric view of the incline adjuster;

[0032] Figure 4 is an alternative isometric view of the incline adjuster;

[0033] Figure 5 is an isometric view of the incline adjuster in the process of being adjusted;

[0034] Figure 6 is an isometric view of the incline adjuster in a more advanced stage of adjustment;

[0035] Figure 7 is a side elevation of the incline adjuster; and

[0036] Figure 8 is an isometric view of the incline adjuster when at its most reclined setting.

[0037] DETAILED DESCRIPTION

[0038] Referring to Figure 1, the wheelchair 1 comprises a seat support 2 and a backrest support 3. For ease of reference these are shown without the padding and upholstery that would normally cover them. The wheelchair also incorporates a backrest recline adjuster 4 which extends from one side of the wheelchair to the other.

[0039] Referring to Figure 2, for ease of understanding the recline adjuster 4 is shown in darker colours so as to contrast it with the faded of ghosted other parts of the wheelchair.

[0040] Referring to Figures 3 8( 4, the recline adjuster 4 is shown isolated from the other parts of the wheelchair. Each side of the recline adjuster has an amber backrest mount 5 comprising a pair of plates, a blue notched catch 6, and a grey locking mount 7.

[0041] For each side of the recline adjuster 4, a mid-part of the backrest mount 5 is pivotally connected to an upper end of the locking mount 7 by a bolt 8, and the lower end of the backrest mount 5 is also pivotally connected to the rear end of the notched catch 6 by another bolt 9.

[0042] Further, for each side, the lower end of the grey locking mount 7 has a locking bolt 10 that is engaged in a slot 11 of the catch 6. As illustrated, the blue catch 6 has a plurality of notches 12 and each of these defines a different locking position. For each of these locking positions the locking bolt 10 lodges in a different one of the notches to lock the backrest mount, and therefore the wheelchair’s backrest, at a desired angle of recline.

[0043] Referring to Figures 5, 6 and 7, to enable the backrest to move to a different one of the locking positions, ie to change the angle of the backrest, the recline adjuster has a red / orange lever 13 at one side. In this case the lever is in the form of a pedal. A midpart of the lever is pivotally connected to a mid-part of the locking mount 7 by a further bolt 14 (see Figure 3).

[0044] When the rearward end 15 of the lever is moved down by foot, or optionally by hand, the forward end 16 of the lever moves upwards. Because the forward end 16 of the lever is pivotally connected to the forward end of the catch 6 by a guide pin 17, when the lever moves in this way it drives the catch 6 upwards so that that it is above and free from the locking bolt 10 and is therefore free from whatever notch 12 it was in at the time.

[0045] With the notched catch 6 freed it can move forwards or backwards until the backrest has reached the desired new recline position. At that point the lever is released so that catch 6 returns to a resting position under the bias of a spring 18 shown in Figure 8, ie so that catch 6 moves down and the locking bolt 10 engages with a new one of the notches, to lock the backrest in the new recline angle. As also indicated in Figure 8, the spring 18 contracts and expands against the green spring housing 19. The process can be repeated, to move the backrest to any other recline angle corresponding to one or other of the notches 12.

[0046] The most reclined position for the backrest occurs when the components are as shown in Figure 3, and the most non-reclined or upright position occurs when the components are arranged as shown in Figure 4. As the backrest moves from one to the other the other the guide pin 17 slides along a confined pathway or slot 20 in the lever 13.

[0047] Because the forward ends of the notched catches 6 are joined by a cross-shaft 21 , the movements caused by the lever at one side of the recline adjuster are automatically replicated at the opposite side. The recline adjuster therefore supportively drives recline adjustment at each side of the wheelchair. As indicated in Figure 4, the crossshaft is telescoping so that it is length adjustable to enable the incline adjuster to be used with wheelchairs of different width. Returning to Figure 1 , when the incline adjuster is installed, each amber backrest mount 5 receives and secures to a respective one of the wheelchair’s backrest canes 22 (see Figure 1). Further, each grey locking mount 7 rigidly attaches to a respective rail 23 of the wheelchair’s frame that extends in the front to back direction of the wheelchair. To facilitate this, each locking mount 7 incorporates a rounded internal space 24 complementary to the associated rail 23 (see Figure 3). The arrangement is such that each locking mount 7 does not move when installed, but allows for the amber backrest mount 5, the blue catch 6, the lever 13 and the cross-shaft 21 , to move with respect to it as the recline angle is being adjusted.

[0048] The preferred embodiment described with respect to the drawings is a wheelchair, however in other embodiments the invention may be applies to seats of other types, for example to stationary seats for people with special postural care needs or to work or leisure seats generally.

[0049] While some preferred embodiments of the invention have been described by way of example it should be appreciated that modifications and improvements can occur without departing from the scope of the following claims. It should also be appreciated that generic terms used in the claims, for example “backrest mount”, “locking mount” and “catch”, should not be seen as limited to the particular parts exemplified in the drawings even if they have the same name there.

[0050] In terms of disclosure, this document hereby discloses each item, feature or step mentioned herein in combination with one or more of any of the other item, feature or step disclosed herein, in each case regardless of whether such combination is claimed.

Claims

CLAIMS1. A chair comprising:• a seat;• a backrest; and• a backrest adjuster comprising a set of: o a locking mount; o a backrest mount; o a notched catch having a selection of notches each adapted to engage with the locking mount in turn; and o a lever (eg a pedal); the adjuster being formed such that:• it is able to lock the backrest in a recline position in which a first one of the notches is engaged with the locking mount; and• pivoting the lever causes the catch to raise and disengage with the locking mount to enable the catch to move forwards or backwards with respect to the locking mount such that the backrest mount pivots about a connection to the notched catch and also pivots about a connection to the locking mount to adjust the recline angle of the backrest and be locked in that position by engagement of a second one of the notches with the locking mount.

2. A chair according to claim 1, wherein the lever is pivotally connected to the locking mount.

3. A chair according to claim 1 or 2, wherein the notched catch has a guide pin adapted to slide along a guide slot in the lever as the catch moves with respect to locking mount.

4. A chair according to claim 1 , 2 or 3, wherein the locking mount comprises a pin adapted to engage with the notches respectively to in each case lock the backrest in one of the recline positions.

5. A chair according to any one of the preceding claims, wherein the locking mount is rigidly fixed so that it is unable to move, but wherein the backrest mount, the notched catch and the lever can move with respect to it.

6. A chair according to any one of the preceding claims, comprising a spring which acts between the locking mount and the notched catch to spring bias the notched catch downwards to engage with the locking mount, but such that downward movement of the lever overcomes the spring bias.

7. A chair according to claim 6, wherein the backrest mount is secured to a side bar of a frame of the chair.

8. A chair according to any one of the preceding claims, wherein each backrest mount comprises a pair of plates arranged in parallel alignment.

9. A chair according to any one of the preceding claims, wherein backrest adjuster has a second set of each of the backrest mount, the locking mount and the notched catch arranged in similar relationship to one another as the first mentioned set and being disposed at an opposite side of the chair, the first and second mentioned sets being connected by a cross-shaft adapted to transfer recline adjustment force from one side of the chair to the other.

10. A chair according to any one of the preceding claims in the form of a wheelchair.

11. A chair according to claim 1 , wherein: a) the lever is pivotally connected to the locking mount; b) the notched catch has a guide pin adapted to slide along a guide slot in the lever as the catch moves with respect to locking mount; c) the locking mount comprises a pin adapted to engage with the notches respectively to in each case lock the backrest in one of the recline positions; d) the locking mount is rigidly fixed so that it is unable to move, but wherein the backrest mount, the notched catch and the lever can move with respect to it; and e) there is a spring which acts between the locking mount and the catch to spring-bias the catch downwards to engage with the locking mount but such that downward movement of the lever overcomes the spring bias.

12. A chair according to claim 11, wherein backrest adjuster has a second set of each of the backrest mount, the locking mount and the notched catch arranged in similar relationship to one another as the first mentioned set and being disposed at an opposite side of the chair, the first and second mentioned sets being connected bya cross-shaft adapted to transfer recline adjustment force from one side of the chair to the other.

13. A chair according to claim 11 or 12 in the form of a wheelchair.

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