Chair and supports

An adjustable support assembly for use in a chair has a mounting member 602, a support 605 for supporting part of the body of a chair occupant, and a carrier 611 slidably carrying the support 605. The support has a plurality of engagement features 621 and the carrier has an engagement member 615 that is selectively engageable with the engagement features to enable the support to be selectively positioned relative to the carrier at a plurality of positions. A biasing arrangement 607 operatively connects the carrier 611 to the mounting member 603 and forwardly biases the carrier 611 and support 605. The engagement between the engagement member 615 and an engaged engagement feature 621 increases upon application of rearward force to the support.

FIELD OF THE INVENTION

The invention relates generally to chairs and associated supports. More particularly, although not exclusively, the invention relates to office chairs.

BACKGROUND TO THE INVENTION

Traditionally chairs have been designed to support an occupant in a single ‘correct’ seating position. More recently, chairs have been provided with recline mechanisms between the support frame, seat and/or back of the chair, which enable the seat and back to move relative to the support frame so that an occupant can move from an upright to a reclined position. Such chairs sometimes also include additional flexibility or adjustments, to enable an occupant to sit in a less standard side-sitting or angled position while still being fully supported by the chair.

Unlike most traditional chairs which have plush-looking cushioning, the more recent adjustable chairs are targeted at the ‘progressive’ end of the market. The appearance of those modern chairs, can, in some instances, challenge a user's understanding, as the chairs will often look highly mechanistic and won't have the perceived volume and comfort of a cushioned textile-covered chair. Additionally, some people can associate a modern mechanistic chair design with high cost, meaning they may be less likely to want to purchase the chair, particularly in times of financial hardship.

There is a need for a chair that has a more conventional and traditional appearance, while still providing the ergonomic benefits and functionality of the more modern ‘progressive’ chairs. There is also a need for such a chair at a low cost point.

Chairs are also often provided with adjustable supports, such as lumbar, head or neck support assemblies. Often, the supports are height adjustable. Typically, there are two types of adjustment mechanisms for such supports. The first type requires the release of an actuator by a user, to release a position lock and enable the user to adjust the position of the support. Such arrangements are typically mechanically complex and may be expensive. An alternative type of support may be adjusted through the use of force, with the force that is manually applied by a user to adjust the position of the support overriding friction provided within the adjustment mechanism. Often, the purpose of such a support is to apply a forwardly-directed support force to an occupant when the occupant applies a rearward force against the support with a body part. With a friction-type mechanism, if the occupant force is not applied directly rearwardly and instead comprises an up or down component, the user can inadvertently cause the height of the support to adjust when leaning back against the support.

It is an object of at least preferred embodiments of the present invention to provide a chair or component that addresses at least one of the disadvantages outlined above, or that at least provides the public with a useful choice.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, there is provided an adjustable support assembly for use in a chair, the support assembly comprising:a mounting member;a support for supporting part of the body of a chair occupant;a carrier slidably carrying the support, the support comprising a plurality of engagement features and the carrier comprising an engagement member that is selectively engageable with the engagement features to enable the support to be selectively positioned relative to the carrier at a plurality of positions; anda biasing arrangement operatively connecting the carrier to the mounting member and configured to forwardly bias the carrier and support;wherein the engagement between the engagement member and an engaged engagement features increases upon application of rearward force to the support.

In an embodiment, the biasing arrangement comprises a biasing member that acts on the engagement member to bias the engagement member toward the support. In an embodiment, the biasing member resists rearward movement of the engagement member toward the mounting member more than it resists rearward movement of the carrier toward the mounting member, upon application of the rearward force to the support.

In an embodiment, the biasing arrangement comprises: an intermediate member operatively connected to the mounting member and to the carrier; a first biasing member arranged between the mounting member and the intermediate member; and a second biasing member arranged between the carrier and the intermediate member.

In an embodiment, the first and second biasing members are oppositely oriented torsion springs.

In an embodiment, the intermediate member is pivotable relative to the mounting member about a first axis and the carrier is pivotable relative to the intermediate member about a second substantially parallel axis. In an embodiment, the adjustable support further comprises at least one link arm with a first end that is pivotable relative to either the mounting member or the intermediate member and a second end that is slidable relative to the other of the mounting member or the intermediate member. In an embodiment, the adjustable support comprises two link arms, each arm having a first end slidable in a slot on the mounting member and a second end pivotable about the intermediate member second axis.

In an embodiment, the engagement member engages the engagement features in a forward-rearward direction.

In an embodiment, the support is tiltable relative to the mounting member.

In an embodiment, the support is height adjustable.

In an embodiment, the engagement member is resilient.

In an embodiment, the carrier comprises a guide for slidably engaging a complementary guide feature on a rear side of the support. In an embodiment, the guide feature on the support comprises a guide projection or flange, and the carrier comprises at least one guide channel for slidably receiving the guide projection or flange.

In an embodiment, the guide feature on the support is provided by a guide member fixed to the support.

In an embodiment, the engagement features comprise rearward facing, arcuate notches; and the engagement member comprises an arcuate forwardly directed projection.

In an embodiment, the support is a lumbar support. Alternatively, the support could be a different type of support such as a head or neck support for example.

In an embodiment, the support is forwardly concave in plan view, and comprises a central, substantially vertical recess to accommodate the spine of a user.

In an embodiment, the mounting member is configured for mounting to a back frame of a chair.

In accordance with a second aspect of the present invention, there is provided a chair comprising a back frame having two side members, and an adjustable support as outlined in relation to the first aspect above, wherein the mounting member is attached to the two side members.

In an embodiment, the mounting member is fixed relative to the two side members. Alternatively, the mounting member could be moveable relative to the side members.

In an embodiment, the back frame supports a compliant back portion, and the support is positioned rear of the compliant back portion.

In an embodiment, the support is rearwardly spaced from the back portion in the absence of a rearward load on the back portion, and at least a part of the back portion is moved rearward to contact the support upon application of a sufficient rearward force to the compliant back portion.

In accordance with a third aspect of the present invention, there is provided a moulded article suitable for strain orientation, the article comprising:a plurality of first elongate straps formed in a first layer;a plurality of second elongate straps formed in a second layer, so that at least some of the first elongate straps overlap with at least some of the second elongate straps; anda plurality of joiner members that are integrally moulded with the first elongate straps and with the second elongate straps, and that connect between the first elongate straps and the second elongate straps in the regions in which the first elongate straps and the second elongate straps overlap.

In an embodiment, at least a portion of the first elongate straps, at least a portion of the second elongate straps, and at least a portion of the joiner members are suitable for strain orientation. In an embodiment, substantially the entire first elongate straps, substantially the entire second elongate straps, and substantially the entire joiner members are suitable for strain orientation.

In an embodiment, the first elongate straps comprise necked regions adjacent the joiner members, to compensate for a reduction in strain orientation due to the additional material of the joiner members. In an embodiment, the necked regions are formed by notches or recesses extending into sides of the first elongate straps. In an embodiment, the notches or recesses are configured such that post-strain orientation, the sides of the first elongate straps are substantially parallel along substantially their entire lengths.

In an embodiment, the second elongate straps comprise necked regions adjacent the joiner members, to compensate for a reduction in strain orientation due to the additional material of the joiner members. In an embodiment, the necked regions are formed by notches or recesses extending into sides of the second elongate straps. In an embodiment, the notches or recesses are configured such that post-strain orientation, the sides of the second elongate straps are substantially parallel along substantially their entire lengths.

In an embodiment, the moulded article is formed from a polymeric resin. As used herein, a ‘polymeric resin’ is a plastic raw material suitable for injection moulding. The resin may be a single plastic material, or may comprise a plurality of plastic materials. In an embodiment, the moulded article is moulded from a resin comprising a thermoplastic polyester elastomer.

In an embodiment, the thermoplastic polyester elastomer comprises a block copolymer. In an embodiment, the block copolymer comprises a hard segment and a soft segment. In an embodiment, the thermoplastic polyester elastomer is a block copolymer of polybutylene terephthalate and polyether glycol.

In an embodiment, the resin is selected such that the moulded article, prior to strain orientation, has a hardness in the range of about 30D to about 55D when tested in accordance with ASTM 2240. In an embodiment, the resin is selected such that prior to strain orientation, the moulded article has a hardness in the range of about 30D to about 46D, preferably in the range of about 35D to about 45D, preferably in the range of about 36D to about 44D, more preferably in the range of about 37D to about 43D, more preferably in the range of about 38D to about 42D, more preferably in the range of about 39D to about 41D, most preferably about 40D.

The thermoplastic polyester resin is preferably one of HYTREL 4069, HYTREL 4556, HYTREL 5526, HYTREL 5556, HYTREL 3078. The resin may additionally include stabilisers and/or additives to achieve desired properties, for example to improve its resistance to UV light, fire, heat aging, moisture, and/or to make the resin a suitable colour.

It will be appreciated that the article could be moulded from other resins having suitable properties.

The first elongate straps may comprise a plurality of elongate straps extending in a first generally longitudinal direction. The second elongate straps may comprise a plurality of elongate straps extending in a second direction that is generally transverse to the first generally longitudinal direction, for example. Alternatively, the straps may be oriented in any suitable way relative to one another. It is preferred that the first elongate straps in the first layer extend longitudinally, and the second elongate straps in the second layer extend transversely.

The generally longitudinally extending elongate straps may differ from the generally transversely extending elongate straps. For example, the generally longitudinally extending elongate straps may have a smaller cross-section than the generally transversely extending elongate straps. However, it is preferred that the cross-sections of the generally longitudinally extending elongate straps are substantially the same as the generally transversely extending elongate straps, at least in the unnecked regions of the straps.

Preferably, at least some of the elongate straps of the moulded article have a cross-sectional dimension of about 12 mm or less, more preferably of about 2.5 mm or less. Preferably, at least a majority of the elongate straps of the moulded article have a cross-sectional dimension of about 12 mm or less, more preferably of about 5 mm or less, more preferably of about 2.5 mm or less. Preferably, at least some of the elongate straps of the moulded article have a depth of about 1.5 mm or about 2 mm.

In an embodiment, the pre-strain orientation depth of each strap is about 1.5 mm or about 2 mm, the generally transversely extending straps have a cross-sectional width (in the longitudinal direction) in the unnecked regions of about 12 mm and in the necked regions of about 10 mm, and the generally longitudinally extending straps have a cross-sectional width (in the transverse direction) in the unnecked regions of about 12 mm and in the necked regions of about 9.4 mm. Preferably, the dimensions are configured such that post-strain orientation, the depth of each strap is about 1.0 mm, the generally transversely extending straps have a cross-sectional width (in the longitudinal direction) in the necked and unnecked regions of about 8 mm, and the generally longitudinally extending straps have a cross-sectional width (in the transverse direction) in the necked and unnecked regions of about 8 mm.

It will be appreciated that the entire moulded article may be formed of the first elongate straps and the second elongate straps. Preferably, at least a major part of the moulded article is formed of the first elongate straps and the second elongate straps.

Alternatively, only part of the moulded article may be formed of the first and second elongate straps, and the moulded article may additionally be provided with attachment features that are integrally moulded into the article.

At least part of the moulded article may have a curved profile that is formed as part of the moulding process. By way of example only, at least part of the moulded article may have a curved side profile and/or a curved top profile that is formed as part of the moulding process. As an alternative, the moulded article may be substantially flat but may for example be held in a contoured non-flat shape when supported by a frame in use.

Preferably, at least part of the article is capable of being stretched to at least about 400%, preferably at least about 450%, preferably at least about 500%, preferably at least about 600%, preferably at least about 700%, preferably at least about 800%, preferably at least about 900%, of an initial dimension without failure, such that strain orientation occurs. Preferably the straps are stretched to about 450% of their initial lengths to cause strain orientation, and have a post-relaxation length of about 210% of their initial lengths.

The article may be a support surface for a chair. For example, the article may be a back support or seat support for a chair that is subsequently mounted to a frame to support the membrane to form a compliant suspended support surface. However, the method may be used to form any other suitable type of article.

In accordance with a fourth aspect of the present invention, there is provided a method of assembling a support, comprising:providing a frame;providing a moulded article as outlined in relation to the third aspect above, wherein at least part of the moulded article has an as-moulded dimension less than a corresponding dimension of the frame;stretching said at least part of the article so as to have a stretched dimension greater than the corresponding dimension of the frame and such that strain orientation of at least a portion of the first elongate straps and at least a portion of the second elongate straps occurs;relaxing said at least part of the article so as to have a post-relaxation dimension between the as-moulded dimension and the stretched dimension;and supporting the article from the frame.

In an embodiment, the frame comprises an opening that is at least partly bounded by frame members, and the method comprises supporting the article from the frame with part of the article extending across the opening, to form a compliant suspended support surface. For example, the frame may comprise side members and upper and lower members (or front and rear members in the case of a seat frame), and the frame members may bound one or more openings that are covered by the article when supported by the frame.

In an embodiment, the first elongate straps comprise generally longitudinally extending straps, and the second elongate straps comprise generally transversely extending straps. In an embodiment, the method comprises stretching and relaxing the generally longitudinally extending straps before stretching and relaxing the generally transversely extending straps. In an alternative embodiment, the method comprises stretching and relaxing the generally transversely extending straps before stretching and relaxing the generally longitudinally extending straps. In yet another embodiment, the method comprises stretching and relaxing the generally transversely extending straps concurrently with stretching and relaxing the generally longitudinally extending straps.

In an embodiment, the step of stretching at least part of the article results in stretching of the joiner members such that strain orientation of the joiner members occurs. In an embodiment, the joiner members are strain oriented in both a longitudinal direction and a transverse direction.

In an embodiment, the joiner members are elongate members having as moulded dimensions of 18.5 mm length, 1.0 mm width, and 2.0 mm depth (to form a gap between the connected straps of 2.0 mm). In an embodiment, the joiner members have a post-strain orientation relaxed dimensions of about 28.5 mm long, 0.8 mm wide, and 1.8 mm deep. The joiner members could alternatively have different dimensions or could be any other suitable shape.

In an embodiment, the first elongate straps comprise necked regions adjacent the joiner members to compensate for a reduction in strain orientation due to the additional material of the joiner members. In an embodiment, the necked regions are formed by notches or recesses extending into sides of the first elongate straps, and wherein the sides of the first elongate straps in the relaxed article are substantially parallel along substantially their entire lengths.

In an embodiment, the second elongate straps comprise necked regions adjacent the joiner members to compensate for a reduction in strain orientation due to the additional material of the joiner members. In an embodiment, the necked regions are formed by notches or recesses extending into sides of the second elongate straps, and wherein the sides of the second elongate straps in the relaxed article are substantially parallel along substantially their entire lengths.

The article may be stretched and relaxed in both the transverse and longitudinal dimensions, or in any other suitable direction. The step of stretching may comprise stretching the article in 360°. That is particularly useful if the article comprises an irregular pattern of members and/or diagonal members.

The method may comprise stretching and relaxing the entire article, or may comprise stretching and relaxing part of the article. That is, in the finished support, some parts of the article may have been strain oriented, and other parts may not have been strain oriented. In an embodiment, substantially all of the first and second elongate straps and joiner members of the article have been strain orientated in two directions, and the remainder of the article may not have been strain oriented.

Depending on the material used, in one embodiment the straps are stretched to between about 4 and about 5 times their as-moulded lengths, and preferably about 4.5 times. In an embodiment, the post-strain orientation relaxed lengths of the straps is between about 1.5 and about 2.7 times the as moulded length, preferably about 2.1 times the as-moulded length.

The step of relaxing and supporting may occur concurrently. For example, the article may comprise pockets or the like to capture respective parts of the frame, and the parts may be captured by the pockets as the article is relaxed. Alternatively, the article may be connected to the frame after relaxing the article. For example, following relaxing of the article, the article may be stretched a small amount and then supported from the frame. The stretched dimension for supporting the article from the frame is preferably about 1.1 times its post-strain orientation relaxed dimension, but that will depend on the frame configuration and the preferred strap tension.

The article may be directly connected to the frame such as by portions of one of the article and the frame being received in respective complementary recesses of the other of the article and the frame. For example, the article may be provided with integrally moulded joiner members around at least part of its periphery and that receive hooks or projections on the frame to connect the article to the frame. Alternatively, separate fasteners could be used to connect the article and the frame. As another alternative, one or more retaining strips could be used to connect the article to the frame. Preferably, the article is directly connected to the frame by attachment features that are integrally moulded with the article as part of the moulding process, from the same material as the remainder of the article. The part of the article having the integral attachment features would generally not be strain oriented.

In an embodiment, a surface texture is inmolded on the article as part of the moulding method.

The method may comprise stretching different parts of the article different amounts, to obtain varying properties in the article. However, in a preferred embodiment, the percentage stretch of the first elongate straps is substantially the same as the percentage stretch of the second elongate straps, so they undergo substantially the same amount of strain orientation.

One or more of the first elongate straps may differ in length from other(s) of the first elongate straps. However, each of the first elongate straps is preferably stretched by substantially the same percentage increase in length, to provide substantially the same amount of strain orientation in each of the first elongate straps.

One or more of the second elongate straps may differ in length from other(s) of the second elongate straps. However, each of the second elongate straps is preferably stretched by substantially the same percentage increase in length, to provide substantially the same amount of strain orientation in each of the second elongate straps.

In accordance with a fifth aspect of the present invention, there is provided a back portion for a chair when assembled using the method as outlined in relation to the fourth aspect above.

In accordance with a sixth aspect of the present invention, there is provided a seat portion for a chair when assembled using the method as outlined in relation to the fourth aspect above.

In accordance with a seventh aspect of the present invention there is provided a chair comprising:a supporting frame;a seat portion for supporting a seated occupant;a back portion for supporting the back of a seated occupant and that is reclinable relative to the supporting frame; anda recline mechanism configured to lift the seat portion upon a reclining action of the back portion, the recline mechanism comprising a back support arm operatively connected to the back portion and that is pivotally connected to the supporting frame and is pivotally connected to a relatively forward portion of the seat portion, and a rocker arm that is pivotally connected to the supporting frame, pivotally connected to a relatively rearward portion of the seat portion, and operatively connected to the back support arm to move relative to the back support arm.

In an embodiment, the seat portion moves upwardly and rearwardly when the back portion is reclined. The seat portion may initially move upwardly and forwardly from its initial position during initial recline of the back portion, and then move upwardly and rearwardly so as to move upwardly and rearwardly overall from its initial position.

In an embodiment, the seat portion has a rearward tilt angle when the back portion is not reclined, and the seat portion has a greater rearward tilt angle when the back portion is fully reclined.

In an embodiment, the rocker arm is downwardly forwardly angled when the back portion is not reclined, and is upwardly forwardly angled when the back portion is fully reclined.

In an embodiment, a portion of the back support arm is approximately horizontal when the back portion is not reclined, and is upwardly forwardly angled when the back portion is fully reclined.

In an embodiment, the rocker arm is downwardly forwardly angled when the back portion is not reclined, and is upwardly forwardly angled when the back portion is fully reclined, and wherein a portion of the back support arm is approximately horizontal when the back portion is not reclined, and is upwardly forwardly angled when the back portion is fully reclined, wherein the upward and forward angle of the rocker arm is greater than the upward and forward angle of the portion of the back support arm. In an embodiment, the downward and forward angle of the rocker arm is about 13 degrees below horizontal, and the upward and forward angle of the rocker arm is about 24 degrees above horizontal, and wherein the upward and forward angle of the portion of the back support arm is about 17 degrees above horizontal.

In an embodiment, the pivot connection of the back support arm and the supporting frame is forward of the operative connection of the rocker arm to the supporting frame. In an embodiment, the pivot connection of the rocker arm and the supporting frame is positioned at or adjacent a rear portion of the supporting frame. In an embodiment, the pivot connection of the back support arm and the supporting frame is positioned adjacent and forward of the pivot connection of the rocker arm and the supporting frame. In an embodiment, the pivot connection of the rocker arm and the seat portion is generally aligned with the pivot connection of the back support arm and the supporting frame, in a forward-rearward direction of the chair.

In an embodiment, the pivot connection of the back support arm to the relatively forward portion of the seat portion comprises a pivot and slide connection.

In an embodiment, the rocker arm is operatively connected to the back support arm via a connecting link that is pivotally connected to the back support arm and pivotally connected to the rocker arm. In an embodiment, the pivot connection of the rocker arm and the connecting link is positioned substantially vertically above the pivot connection of the connecting link and the back support arm, when the back portion is not reclined.

In an embodiment, the rocker arm is operatively connected to the back support arm via a pivot and slide connection. In an embodiment, the pivot and slide connection comprises a pin on the rocker arm and a slot in the back support arm. In an embodiment, the pivot and slide connection comprises a roller rotatably mounted on the rocker arm and slidable along a surface of the back support arm.

In an embodiment, the recline mechanism comprises two back support arms operatively connected to the back portion and that are pivotally connected to the supporting frame and are pivotally connected to the relatively forward portion of the seat portion, two rocker arms that are pivotally connected to the supporting frame, pivotally connected to a relatively rearward portion of the seat portion, and operatively connected to a respective one of the back support arms. In an embodiment, the two rocker arms are movably connected relative to the back support arms via two connecting links that are each pivotally connected to a respective one of the back support arms and to a respective one of the rocker arms.

In an embodiment, the supporting frame comprises a transom having a base and a pair of spaced apart side walls, and wherein a portion of each back support arm is positioned inwardly of the side walls of the transom. In an embodiment, each back support arm is pivotally connected to respective one of the side walls of the transom.

In an embodiment, the seat portion comprises a seat support and a seating surface for supporting a seated occupant, wherein the seating surface is selectively moveable in a forward and rearward direction relative to the seat support, and wherein the rocker arm(s) and the back support arm(s) are pivotally connected to the seat support.

In an embodiment, the chair further comprises a recline resistance mechanism to resist movement of the back portion toward the reclined position, wherein the amount of resistance provided by the recline resistance mechanism is selectively adjustable.

In an embodiment, the seat comprises a shell beneath the seating surface and having a central recess in the underside of the shell, and wherein the recline mechanism is substantially housed in the central recess when the back portion is not reclined.

In an embodiment, a vertical height of the recline mechanism is about 40 mm when the back portion is not reclined.

In an embodiment, a forward end of the rocker arm is configured to engage with the seat portion to provide a recline stop that defines the maximum rearward recline of the back portion.

In an embodiment, a forward end of the back support arm is configured to engage with the supporting frame to provide an upright stop that defines the upright position of the back portion.

In accordance with an eighth aspect of the present invention, there is provided a chair comprising:a supporting frame;a seat portion for supporting a seated occupant;a back portion for supporting the back of a seated occupant, the back portion being reclinable relative to the supporting frame between a generally upright position and a generally reclined position; anda recline resistance mechanism to resist movement of the back portion toward the generally reclined position, the recline resistance mechanism comprising a resistance device operatively connected to one of the back portion, the seat portion, or the supporting frame, the recline resistance mechanism further comprising a first retainer and a second retainer that are both operatively connected to another one of the back portion, the seat portion, or the supporting frame, wherein the second retainer is movable to adjust a reaction point between the resistance device and said another one of the back portion, seat portion, or supporting frame, to vary the amount of recline resistance provided by the recline resistance mechanism, wherein the first retainer preloads the resistance device when the back portion is in the generally upright position, and wherein the second retainer is movable to at least one position wherein in the reclined position of the back portion, the reaction point is provided by the second retainer.

In an embodiment, movement of the second retainer does not alter the preload on the resistance device when the back portion is in the generally upright position.

In an embodiment, the first retainer engages the resistance device such that the recline resistance mechanism provides a first level of recline resistance. In an embodiment, the second retainer is movable to a position in which it provides a second level of recline resistance that differs from the first level of recline resistance provided by the first retainer. In an embodiment, the first level of recline resistance provided by the first retainer is a relatively low level of recline resistance, and the second level of recline resistance provided by the second retainer is a relatively high level of recline resistance.

In an embodiment, the second retainer is selectively movable between an engaged position in which the second retainer engages the resistance device when the back portion is reclined from the generally upright position, and a disengaged position. In an embodiment, in the engaged position, the second retainer does not engage the resistance device when the back portion is in the generally upright position.

In an embodiment, the first retainer contacts the resistance device when the back portion is not reclined, whether or not the second retainer is selectively engaged.

In an embodiment, at least one of the retainers is movable relative to the resistance device between a plurality of engagement positions, to provide differing levels of recline resistance.

In an embodiment, the resistance device is operatively connected to the back portion, and the first and second retainers are operatively connected to the supporting frame.

In an embodiment, the resistance device comprises a leaf spring. In an embodiment, the leaf spring has an effective length, a reaction length, and an amount of deflection when the back portion is in the generally reclined position, and wherein in a first position of the second retainer, the effective length, the reaction length, and the amount of deflection are all greater than if the second retainer is in a second position, such that the level of resistance provided by the recline resistance device is relatively high when the second retainer is in the first position and relatively low when the second retainer is in the second position.

In an embodiment, the first position is an engaged position in which the second retainer engages the leaf spring when the back portion is reclined from the generally upright position, and the second position is a disengaged position. Alternatively, the first and second positions may be different engaged positions in which the second retainer engages the leaf spring when the back is reclined from the generally upright position.

In an embodiment, the leaf spring is operatively connected to the back portion to move with the back portion and the first and second retainers are operatively connected to the supporting frame. In an embodiment, the second retainer is pivotally connected to the supporting frame and is selectively engageable with a forward end of the leaf spring.

In an embodiment, the leaf spring is operatively connected to the supporting frame, and the first and second retainers are operatively connected to the back portion to move with the back portion.

In an embodiment, the resistance device comprises a torsion spring. In an embodiment, the torsion spring comprises a leg portion, and the first retainer engages the leg portion.

In an embodiment, the second retainer is movable to engage and disengage an end of the leg portion and wherein the effective spring rate of the torsion spring and thereby the recline resistance is higher when the second retainer is engaged with the end of the leg portion.

In an embodiment, the torsion spring further comprises another leg portion that is operatively connected to the back portion. In an embodiment, the torsion spring comprises a body and two leg portions, and wherein the body is positioned on or spaced apart from the pivot axis of the back portion to the supporting frame.

In an embodiment, the resistance device comprises a plurality of springs, and wherein the first retainer and/or the second retainer is/are engageable with the plurality of springs. By way of example, the springs could be leaf springs, could be torsion springs, or could differ from each other.

The term ‘comprising’ as used in this specification means ‘consisting at least in part of’. When interpreting each statement in this specification that includes the term ‘comprising’, features other than that or those prefaced by the term may also be present. Related terms such as ‘comprise’ and ‘comprises’ are to be interpreted in the same manner.

As used herein the term ‘and/or’ means ‘and’ or ‘or’, or both.

As used herein ‘(s)’ following a noun means the plural and/or singular forms of the noun

The chair may be any suitable form of chair. For example, the chair may be an office chair. The chair could be a different type of chair, including but not limited to a vehicle seat such as a car seat, aircraft seat, or boat seat, or a lounge chair or theatre chair.

Optional features of different embodiments of the invention are described in the accompanying dependent claims.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting. Where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

DETAILED DESCRIPTION OF PREFERRED FORMS

Since the figures illustrate the preferred form chairs from various different angles as convenient to explain certain parts, an arrow marked ‘F’ has been inserted into some of the figures where appropriate to indicate a forward direction of the chair. Accordingly the terms forward, rearward, left side, and right side (or similar) should be construed with reference to the forward direction F of the chair, not necessarily with reference to the orientation shown in the particular figure.

The features of the preferred form chairs are described and shown herein to give a full understanding of the components and operation of the preferred form chair. It will be appreciated that not all of the features described herein need be provided in every chair.

FIGS. 1 to 7show a chair101in accordance with a first preferred form of the present invention.FIGS. 8 to 11show a chair101′ in accordance with a second preferred form of the present invention. Both of the chairs may have any one or more of the features described below. The primary difference between the first preferred form chair101and the second preferred form chair101′, is that the first preferred form chair is a ‘mid-back’ chair, with a back portion501sized and configured to support a seated occupant's back portion up to approximately their shoulder blade region. The second preferred form chair101′ is a ‘high-back’ chair, with the back portion501′ sized and configured to support a seated occupant's back portion up to and including their shoulder region. As the chairs are otherwise substantially the same, like reference numerals indicate like parts in the figures, with a prime (′) indicating the sections that differ.

Each chair has a supporting frame102comprising a base103for supporting the chair on a floor surface. In the form shown the base is a castered base103having a plurality of radially extending legs107extending outwardly from a single central hub. In the form shown, there are five legs. However, it will be appreciated that there may be more or less legs. A caster or roller109is rotatably mounted at the end of radially-extending leg107opposite to the central hub. The casters enable a chair occupant to move the base103and thereby the chair along the ground surface. In an alternative configuration, the chair may comprise a fixed base that does not provide for rolling movement of the chair on the ground surface.

A height adjustable column111is coupled to the central hub of the base and extends upwardly therefrom. The height adjustable column can be any suitable type of pneumatic or gas spring, which enables height adjustment of the chair seat portion171and back portion501,501′ relative to the ground surface. A main transom121of the supporting frame is coupled to an upper end of the height adjustable column111, such that height adjustment of the column causes height adjustment of the transom121and supported components.

A seat portion151for supporting a seated occupant and a back portion501,501′ supporting the back of a seated occupant are coupled to the transom121via a recline mechanism described below, so that the seat portion151and back portion are movable relative to the supporting frame. The seat portion151and back portion501will be described in further detail below.

The chairs101,101′ may be provided with or without arm support assemblies401to support an occupant's arms.

Recline Mechanism

In the preferred form chairs, the back portion501,501′ of the chair is reclinable relative to the supporting frame102between an upright position (FIGS. 3 and 10) and a reclined position (FIG. 7). The chair comprises a recline mechanism201,202coupling the back portion501,501′ to the seat portion and the transom121. The recline mechanism is configured to lift the seat portion151as the back portion501,501′ reclines.

FIGS. 12 to 17show a first preferred form recline mechanism201. In this embodiment, the recline mechanism comprises a back support arm203, a rocker arm211, and a connector link215. The back support arm203is fixed to the back portion501,501′ and extends forward from the back portion501,501′. The angle between the back frame503and the back support arm203is preferably fixed and about 90°. The back support arm203is a rigid member and has a kinked arrangement, with a rearward section203aextending forward from its rear end to pivot219, an upwardly and forwardly angled intermediate section203bbetween pivots219and205, and a forward section203cbetween pivots205and207. Preferably, a portion203cof the back support arm203is approximately horizontal when the back portion501,501′ is upright, and is upwardly forwardly angled when the back portion is reclined.

The back support arm203is pivotally connected to the transom121by a pivot205, and a front end203cof the back support arm203is pivotally connected to a relatively forward portion of the seat portion151via the support161by a pivot and slide207. Preferably, the front end of the back support arm203is connected to the front of the seat portion151. The rocker arm211is pivotally connected to the transom121by a pivot213and has a first relatively forward end pivotally connected to a relatively rearward portion of the seat portion151and a second relatively rearward end pivotally connected to the connector link215, to operatively connect the rocker link211to the back support arm203to move relative to the back support arm203.

The pivot connection213between the rocker arm211and the transom121is positioned at or adjacent a rear portion of the transom121. The pivot connection205between the back support arm203and the transom121is adjacent and forward of the pivot213between the rocker arm211and the transom121. The pivot connection209between the rocker arm and the seat portion151is generally aligned with the pivot connection of the back support arm203and the transom121in a forward-rearward direction of the chair, in both the fully reclined and fully upright configurations of the back portion.

In the first embodiment201, the pivot connection217of the rocker arm211and the connecting link215is positioned substantially vertically above the pivot connection219of the connecting link215and the back support arm203both when the back portion is fully upright and fully reclined. As shown inFIGS. 12 and 13, during recline of the back portion501through an angle α of about 18° from upright, the angle γ between the connecting link215and the back support arm203changes less than about 2°, from about 93.6° to about 95.4°. During that recline, the rocker arm211pivots from a downwardly forwardly angled orientation, from an angle θ of about 13°, preferably about 12.7°, below horizontal when the back portion is fully upright, to an upwardly forwardly angled orientation of about 24°, preferably about 23.8°, above horizontal when the back portion is fully reclined. In the reclined configuration, the upward and forward angle θ of the rocker link211is greater than the upward and forward angle of the portion203cof back support arm203that extends from the transom pivot205to the seat portion pivot207. In this embodiment, the upward and forward angle is about 17.1° in the reclined configuration, and the downward and forward angle is about 0.8° when the back portion is upright.

FIGS. 15 to 17show side views of the recline mechanism ofFIGS. 12 to 14, with the back portion501,501′ in a fully upright (FIG. 15), intermediate (FIG. 16), and fully reclined (FIG. 17) position.

As shown inFIG. 27, the pivot and slide207between the back support arm203and the seat portion151comprises a pin210fixed to an underside of a front portion of the seat portion151, and at least one slot208in a front end203cof the back support arm203. The slot208is a slightly elongated aperture that allows between about 1.5 mm and about 2 mm movement of the pin210along the slot208during recline. Alternatively, the pivot and slide207could comprise any other sliding connection, for example a pin or protrusion at a front end of the back support arm203that slides in a slot in the seat portion103.

FIGS. 18 to 22show a second preferred form recline mechanism202. That embodiment has similar features and functioning to the embodiment ofFIGS. 12 to 17, and like numerals indicate like parts, with a prime (′) indicating the sections that differ. This embodiment differs in that, in place of the connector link215, the rocker link211′ is operatively connected to the back support arm203′ to move relative to the back support arm, via a pivot and slide connection220. The rocker link211′ is pivoted to the transom121at a pivot213′ intermediate its two ends.

The forward-rearward position of the pivot and slide connection220is selected to enable the forward portion of the rocker link211′ between the transom pivot213′ and the seat pivot209to move through the same angle during recline of the back portion501,501′ as for the first embodiment, such that the movement imparted to the seat portion151on recline of the back portion501,501′ is substantially the same for both the first and second embodiments201,202. The pivot and slide connection207between the seat portion151and the back support arm203′ is substantially the same for both the first and second embodiments201,202. It can be seen that the pivots220,205,207of the back support arm are more linear in this embodiment than in the embodiment ofFIGS. 12 to 17.

Preferably, the pivot and slide connection220comprises a pin223on the rocker arm211′ and a slot225in the back support arm203′, as shown inFIGS. 20 to 22. Preferably, between about 2 and about 3 mm, most preferably approximately 2.5 mm of sliding movement is provided by the pivot and slide connection220. The amount of sliding movement provided by the pivot and slide connection220depends on the vertical position of the connection220relative to the back support arm203′ and pivot213′. For a given fore-aft position of the pivot and slide connection220, a lower position of the pivot and slide connection will require more sliding movement than a higher position. Alternatively, the sliding connection may comprise any other suitable sliding connection, for example, a roller rotatably mounted on the rocker arm211′ that is slidable along a surface of the back support arm203′.

The recline mechanisms may comprise a single back support arm203,203′, rocker arm211,211′, and/or rocker link215or pivot and slide220, which may be generally centrally mounted in the chair. Preferably, the chair comprises a pair of back support arms203,203′, a pair of rocker arms211,211′, and a corresponding pair of rocker links215or pivot/slides220that are spaced apart across a transverse width of the chair to provide stability to recline mechanism movement. The two back support arms203,203′ may comprise a single integral member connected via a cross-member, with two forwardly extending arms, or may comprise two separate support arms both operatively connected to the back portion501,501′.

As shown inFIGS. 25 to 30the transom121preferably comprises a pair of spaced apart side walls227and a base229. The back support arms203,203′ are preferably positioned inwardly of the transom side walls227, and pivotally connected at pivot213,213′ to a respective side wall227. The rocker links211,211′ are preferably positioned outwardly of the transom side walls.

FIGS. 15 to 17 and 20 to 22show side views of the recline mechanism with the back portion501,501′ upright, partly reclined and fully reclined. During recline, the seat portion151first moves upwardly and forward, until the rocker links211,211′ are horizontal, and then moves upwardly and rearwardly. When the back portion501,501′ is upright, the seat portion151is angled rearwardly 4°. An underside first surface212aon a front end of the back support arm203abuts a portion of the transom121to provide an upright stop to define the upright position of the back portion.

As the back portion501,501′ reclines and the seat portion151lifts, the rearward tilt of the seat increases, but at a lesser rate than the angular change of the back portion501,501′. The first surface212aon the back support arm203moves out of contact with the transom121during recline.FIG. 17shows the seat portion151when the back portion501,501′ is fully reclined. In the fully reclined position, a second upper surface212bon a front end of the rocker link211,211′ abuts a surface on the seat portion151to provide a recline stop and define the maximum rearward recline of the back portion501,501′. In a preferred embodiment, the seat portion is rearwardly tilted about 4° when the back portion is in the upright position, and rearwardly tilted about 7.8° when the back portion is fully reclined.

It can be seen that the seat portion151preferably lifts upwardly and rearwardly and increases in rearward tilt angle, as the back portion501,501′ is reclined. The lifting of the seat portion provides a ‘weight-compensated’ recline mechanism, meaning more force is required for a heavier seated occupant to recline the back portion than for a lighter seated occupant to do so. As shown inFIG. 14, the effective pivot point221of the seat portion relative to the transom121is a rearward distance RPD of about 374 mm behind the pivot connection205of the back portion to the transom, and is a vertical distance VPD of about 44.2 mm below that pivot connection205. These dimensions are examples only, and may vary.

Due to the main back support arms203,203′ extending forward under a major part of the seat portion151and connecting to a relatively forward portion of the seat portion, the primary lifting of the seat portion during recline of the back portion501,501′ is a lifting of the forward portion of the seat portion. The rocker arms211,211′ by their operative connection to the back support arms203,203′ act as followers to the movement, and lift the rear portion of the seat portion.

The seat portion151comprises a seat support161and a seating surface171for supporting a seated occupant. In a preferred embodiment, the seating surface171is selectively moveable in a forward and rearward direction relative to the seat support161to selectively adjust seat depth relative to the back portion501,501′. The rocker arms211,211′ and the back support arms203,203′ are pivotally connected at pivots207,209to the seat support161. Alternatively, the seating surface171may be fixed to the seat support161and not depth adjustable. In the form shown, the seating surface171is a cushioned and upholstered surface. Alternatively, it may be a compliant slotted seat panel, or a combination of a slotted seat panel and a cushioned and upholstered surface for example.

The recline mechanism201,201′ is a low profile mechanism. As shown inFIG. 20, the vertical height VHRM between top and bottom surfaces of the recline mechanism is preferably about 40 mm. As shown inFIGS. 1 to 11, an underside of the seat portion may comprise a shell181with a central recess. A substantial portion of the recline mechanism including the transom121, is housed within the central recess when the back portion of the chair is upright.

As shown inFIGS. 6, 9 and 10, three actuators191a,191b,191care flush-mounted in the underside shell181, and are provided to enable the occupant to adjust features of the chair by moving the actuators. In one embodiment, the front actuator191aon the left hand side of the chair adjusts the recline resistance (described in more detail below), the actuator191bon the right hand side of the chair adjusts the height and depth of the seating surface171, and the rear actuator191con the left hand side of the chair actuates an upright lock251to prevent recline of the back portion.

FIGS. 23 and 24show details of the seat depth mounting on support161. Transversely spaced portions of the seat panel151acapture corresponding portions of the support161, to slidably mount the panel151aon the support. The support is provided with a rack comprising a plurality of spaced slots161a. A catch body192is mounted to the panel151a, and has teeth192dthat are movable transversely into and out of engagement with the slots161a. When engaged (FIG. 24), the depth position of the seating surface171is locked relative to the support161. When disengaged (FIG. 23), the depth position of the seating surface171can be adjusted by a chair occupant. To adjust the depth, the occupant moves the actuator191bin one direction from neutral which, via coupling link192aand its ball192band socket192cconnection with the catch body192, moves the catch body out of engagement from the track connection with the rack. Upon release of the actuator, a biasing force will cause the catch body192to reengage with the rack to lock the seating surface in one of a plurality of depth adjusted positions. Movement of the actuator in the other direction from neutral will release the gas spring111, enabling the height of the seat portion151to be adjusted.

As shown inFIG. 27, the chair is preferably provided with a generally L-shaped lock member251that is operatively connected to the seat portion151, and is selectively transversely slideable relative to the seat portion151and the transom121. The elongate portion251aof the lock member251extends through an aperture253in the seat portion, and is selectively engageable in aperture255of the transom121. A shorter portion251bof the lock member251extends through an aperture in the seat portion and engages an aperture255aon the other side of the transom121to the aperture255, when the elongate portion is engaged. When the lock member251is engaged in the apertures255a,255, the seat portion151and back portion501,501′ are locked in the upright position. When disengaged from the apertures255a,255, the seat portion151and back portion501,501′ can be reclined.

Recline Resistance Mechanism

The chair101,101′ additionally comprises a recline resistance mechanism301or302to resist movement of the back portion501,501′ toward the reclined position. The amount of resistance provided by the recline resistance mechanism301or302is selectively adjustable.

FIGS. 25 to 32(b) show the first preferred form recline resistance mechanism301.

The recline resistance mechanism301comprises a first retainer307, a resistance device305, and a movable second retainer309. The resistance device comprises a leaf spring305operatively fixed at one end to the back portion501,501′ by being connected to the back support arm203. The first retainer307is attached to the transom121and engages an upper surface of the leaf spring305at least when the back portion501,501′ is in the upright position. In the upright position, surface212aof the back support arm203engages a surface of the transom121and the first retainer307applies a downward force to the leaf spring, preloading the leaf spring305and biasing the back portion501,501′ upright.

The second retainer309comprises a saddle that is pivotally mounted to the transom121and selectively pivotable between a disengaged position (FIGS. 29, 30, 32(a)) and an engaged position (FIGS. 25, 26, 28, 31, 32(b)). When the second retainer309is in the disengaged position, it is out of contact with the leaf spring throughout any movement of the leaf spring305during recline of the back portion501,501′. In that disengaged configuration, when the back portion501is reclined relative to the transom, the leaf spring deflects to resist the recline. The leaf spring reacts against the transom at the first retainer307to provide the deflection, as shown inFIG. 32(a). When the second retainer309is in the engaged position, it is positioned over a top surface of the leaf spring305, forward of the first retainer307. The second retainer309does not apply a downward force to, or preload, the leaf spring305when the back portion501,501′ is in the upright position. Preferably, when the back portion501,501′ is in the upright position, the second retainer309does not contact the top surface of the leaf spring305.

Preferably, when engaged, the second retainer309comes into contact with the spring305after between about 3° and 5° of recline of the back portion. When the back portion501,501′ is reclined relative to the transom with the second retainer309engaged, the leaf spring305deflects to resist the recline and, beyond about 3° to 5° of recline, reacts against the transom121at the second retainer309. The leaf spring305moves out of contact and away from the first retainer307as the back portion501,501′ reclines, as shown inFIG. 32(b).

As shown inFIG. 27, a housing bracket319operatively connects the back portion501,501′ to the recline mechanism201and the recline resistance mechanism301. A bottom portion of the back portion501,501′ is fixed to this housing bracket319, by fasteners such as bolts for example. The housing bracket319is also fixed to the back support arm203by fasteners such as bolts. The connecting link215of the recline mechanism is pivotally connected to the back support arm203at pivot219. One end of the leaf spring305is positioned within the housing bracket319and located in a forward/rearward direction relative to the housing bracket with a pin320. The housing bracket319comprises two spaced apart transverse rods positioned within the housing. A first rod323is positioned towards a lower, front portion of the housing bracket319, and a second rod321is positioned above and rear of the first rod323. The leaf spring extends into the housing bracket, over the first rod323and under the second rod321such that the first and second rods effectively hold the leaf spring in cantilevered relation to the housing bracket319and thereby to the back portion501,501′. The rods321,323react against the recline force of the spring as the back portion501,501′ is reclined. The rods321,323increase the effective length of the spring305compared to a straight cantilevered connection of the spring305to the housing319, and also reduce stress concentrations on the spring adjacent the housing.

In a preferred embodiment, the leaf spring305comprises a composite material, for example unidirectional glass fibre-reinforced epoxy composite. Alternatively, the leaf spring may comprise spring steel for example.

It can be seen inFIG. 31that the leaf spring305has an effective length BR when only the first retainer307is engaged, and a longer effective length BS when the second retainer309is engaged (and the back portion501,501′ is being reclined). The leaf spring305also has a first reaction length PR between the main pivot205of the back portion501,501′ to the main transom121when only the first retainer307is engaged, and a second longer reaction length PS when the second retainer309is engaged (and the back portion501,501′ is being reclined).

Referring now toFIGS. 32(a) and 32(b), when only the first retainer307is engaged, the spring deflects by a first amount D1and the back portion is reclined, whereas with the second retainer engaged, the same point of the leaf spring305deflects a larger second amount D2. The result is that with the second retainer309engaged, the spring's effective length, reaction length, and amount of deflection are all greater during recline of the back portion, than when only the first retainer is engaged. Because the effective length of the leaf spring305is longer with the second retainer309engaged, that provides a lower spring rate than with only the first retainer307engaged. However, the longer reaction length PS and greater spring deflection D2overcome the lower spring rate of the effectively longer spring.

Because the first retainer307preloads the spring, and the second retainer309does not contact the spring when it is brought into the engaged position and the back portion501,501′ is upright, no force on the spring305needs to be overcome to adjust the position of the second retainer309.

As shown schematically inFIG. 28for example, the second retainer309is adjusted by a Bowden cable315. The cable has a cable housing and an inner cable portion that is movable relative to the housing. The inner portion317is coupled to an actuator191aon the underside of the seat portion for use by the seated occupant. When the occupant moves the actuator with their hand, that causes movement of the inner portion of the cable317. That will cause movement of the other end of the inner portion of the cable, and associated pivoting of the second retainer309into or out of engagement with the leaf spring305. The free end of the leaf spring305comprises a retainer catch313that latches the second retainer309when the second retainer is in the engaged position and the back portion501,501′ is reclined. When the second retainer309is engaged with the leaf spring305, the second retainer is able to pivot relative to the transom to rotate with the end of the leaf spring as the back portion501,501′ is reclined. The retainer catch313prevents the second retainer from inadvertently pivoting out of engagement with the leaf spring305during recline of the back portion501,501′.

As can be seen fromFIGS. 32(a) and 32(b), if the back portion501,501′ of the chair is reclined when the second retainer309is in the disengaged position, and the user attempts to move the second retainer309into the engaged position ofFIG. 32(b), the second retainer309would impact on the end of the raised leaf spring305. Similarly, if the user attempts to move the second retainer309out of engagement with the leaf spring305when the back portion501,501′ of the chair is reclined, the force applied by the leaf spring305against the second retainer309would be too high to allow disengagement of the second retainer309from the spring. Accordingly, as shown schematically inFIG. 28, the cable includes a first biasing device318such as a coil spring, which enables the occupant to pre-set the second retainer309into or out of engagement with the leaf spring305when the back portion501,501′ is reclined, and which will cause the adjustment to occur only once the back portion has been returned to the upright position and the second retainer309can engage or disengage from the leaf spring305. This is achieved by way of a second biasing device such as a coil spring318athat is provided on a portion of the cable315.

The second biasing device318ais stiffer than the first biasing device318and in normal use, when the retainer is engaged or disengaged, the second biasing device318ais uncompressed. When the second retainer309is disengaged and the back portion is reclined, if the occupant pre-sets the second retainer309into engagement with the leaf spring305, the second retainer will try to engage the leaf spring but will not be able to pivot into position due to contact with the end of the leaf spring. Instead the second biasing device318awill compress and when the chair is returned to upright the second biasing device318awill pull the second retainer309into engagement with the leaf spring305. Similarly, when the second retainer309is engaged with the leaf spring305and the back portion is reclined, if the occupant pre-sets the second retainer309to disengage the leaf spring305, the second retainer will try to disengage but will not be able to pivot out of engagement. Instead the cable315will become slack. When the chair is returned to upright the first biasing device318will push the second retainer309out of engagement with the leaf spring305.

The above description describes one preferred form of the recline resistance mechanism301only. In an alternative embodiment, rather than being pivotally connected to the transom121, the second retainer309may be slidable relative to the leaf spring305to alter the reaction point of the spring305against the transom121. In such an embodiment, when the back portion501,501′ is in the generally upright position, the second retainer309would be freely slidable relative to the spring without altering the preload on the spring305. Further, in addition to the first307and second309retainers, there may be one or more additional retainers engageable with the leaf spring305to provide further levels of recline resistance.

The preferred embodiment shown in theFIGS. 25 to 32(b) comprises a single leaf spring305. Alternatively, the recline resistance mechanism301may comprise two or more leaf springs. The first307and second309and any additional retainers may engage only a single one of those springs, or may engage more than one spring at the same time. For example, in an embodiment having two leaf springs each positioned towards an opposite side of the transom121, each leaf spring may comprise a respective first retainer307attached to the transom121. A second retainer309pivotally attached to the transom may comprise two saddles arranged to engage both of the springs when the second retainer is adjusted to the high resistance position.

FIGS. 33 to 36show a second preferred form recline resistance mechanism302. The features and functioning of this embodiment are similar to the embodiment described above, and like numerals indicate like parts. In this embodiment, rather than using a leaf spring305, the resistance device is a torsion spring325. The torsion spring325comprises a first leg326aoperatively connected to the transom, and a second leg326boperatively connected to the back portion. The second leg326bcomprises a bent end that extends transversely and is received in an aperture in the back support arm203. In the form shown, the torsion spring325is a double coil torsion spring, with two legs326boperatively connected to the back portion, and two legs326aoperatively connected to the transom121. In a preferred embodiment, the pivot of the torsion spring is positioned behind the pivot205of the back portion. Alternatively, the pivot of the torsion spring could be coincident with the pivot205(as shown), or forward of the pivot205. As in the above described leaf spring embodiment, a first retainer307′ fixed to the transom121engages a top surface of the torsion spring legs326ato operatively connect the spring legs326ato the transom121and apply a preload to the torsion spring325when the back portion501,501′ is in the upright position and to provide a first recline resistance when the back portion501,501′ is reclined. A second retainer309′ in the form of a hook is pivotally attached to the transom121at pivot311′, and is pivotable to engage a cross member between the legs326awhen the back portion501,501′ is in the generally upright configuration to increase the recline resistance during recline of the back portion.

In embodiments where the pivot of the torsion spring is positioned rearward of the back portion pivot205, the legs326aof the torsion spring interact with the retainers in a similar manner to the leaf spring embodiment. That is, with the second retainer309′ engaged, the spring's reaction length and amount of deflection are greater during recline of the back portion than when only the first retainer307′ is engaged. Because the effective length of the spring legs326ais longer with the second retainer309′ engaged, that provides a lower spring rate than with only the first retainer307′ engaged. However, the longer reaction length and greater spring deflection overcome the lower spring rate of the effectively longer spring.

In alternative embodiments, rather than being operatively connected between the back portion501,501′ and the transom121, the resistance mechanisms301,302may be operatively connected between the seat portion151and the transom121or between the back portion501,501′ and the seat portion151. Additionally or alternatively, the recline resistance mechanisms could be used in chairs having the second preferred form recline mechanism201′ described above, or in chairs having other types of recline mechanisms.

Arm Assemblies

The chair101,101′ has a pair of arm assemblies401positioned one on either side of the seat assembly151. A preferred form arm assembly is shown inFIGS. 37 and 38. Each arm assembly401comprises a support assembly402and an arm rest403. The arm rest403may be fixed in position relative to the support assembly402so that the arm rest is only height adjustable. Alternatively, the arm rest403may be generally horizontally movable relative to the support assembly402as well as height adjustable. By way of example, the arm rest403may be selectively movable relative to the support assembly in a forward and rearward direction, in a side-to-side direction, and/or pivotally about a substantially vertical axis.

In the form shown, the supports402are connected to the back portion501,501′ so that the arm rests move with the back portion as it reclines. Alternatively, the supports402could connect to a different part of the chair, such as the seat portion151or the supporting frame (e.g. the transom121).

The support assembly402supporting the movable arm rest403is preferably height adjustable and is mounted to a chair101,101′. Referring toFIGS. 39 to 44, the height adjustable support assembly402preferably comprises a support body406, a sleeve405that receives the body, and a lever411. The body406is selectively height adjustable in the sleeve413by actuation of the lever, to adjust the height of the arm rest403relative to the chair101,101′.

The sleeve405comprises two inner sleeve portions415,417, that sit within an outer sleeve member413and are held in place by a mounting plate419. Preferably one of the inner sleeve portions417comprises a collar417athat fits over the other inner sleeve portion415and the mounting plate419, to ensure correct alignment of the three pieces, and for aesthetics. Alternatively the collar417amay be a separate cover member. The inner surface of each inner sleeve portion415,417comprises a detented groove416,418with an elongate, vertical groove portion416b,418band a plurality of detents416a,416b. In the embodiment shown, the detents416a,418acomprise horizontal notches extending rearwardly from the elongate vertical slots416b,418b.

The support body406comprises an elongate hollow curved substantially vertical tubular portion406aand a forwardly extending substantially horizontal cantilevered portion406bextending from the top of the hollow portion406a. The hollow portion406aof the support body403is received by the sleeve405,413,415,417. The cantilevered portion406boperatively supports the arm rest402. The arm cap member407attaches to and covers the top of both the cantilevered406band elongate hollow portions406aof the support body406by fasteners (not shown).

The support body406is preferably a moulded plastic member. A steel reinforcement member421is positioned within the body406.

The lever411is an inverted L-shaped member positioned within the support body406and pivotable relative to the body406about a pivot407athat is formed by a pin423extending through apertures in the lever411and the arm cap407. One leg of the lever is positioned within the elongate hollow portion406aof the support body and the other leg of the lever is positioned in the cantilevered portion406bof the support body. The lever411is attached to the reinforcement member421and the cap member407, or otherwise operatively pivotally attached to the support body406.

A lower end of the lever411comprises a guide protrusion427and a lock pin429. The lock pin429passes through the centre of the protrusion and through slots (not shown) provided on either side of the body406. The lock pin429extends into the detented grooves416,418on the inner sleeve portions415,417. The protrusion moves forward and rearward in the slots in the body406as the lever411is pivoted about its pivot pin423. The two ends of the slots in the body and the grooves416,418act as stops against the protrusion427to limit pivoting of the lever411. The reinforcement member421defines a further slot425that provides clearance for the protrusion427on the lever so that the guide protrusion427can move relative to the reinforcement member421as the lever411pivots.

The lever411comprises an actuator portion410at its upper and forward end. An opening in the underside of the cantilevered portion406bof the support body406exposes the actuator portion410. Preferably, the actuator portion protrudes through that opening to enable the actuator portion410to be readily located by a user. Pressing or pulling upwardly on or releasing the actuator portion410causes the lever411to pivot about pivot423. As the lever411pivots, the protrusion427slides in the reinforcement member slot425and the lock pin429slides in slots406cin the body to move within the detented grooves416,418to engage and disengage the detents416a,418a.

FIG. 41shows the support assembly locked in the lowest position, where the lock pin429is engaged with the lowermost detents416a,418a. A biasing device424, which in the form shown is a coil spring, is positioned between the actuator portion410and the arm body cap407to bias the actuator portion410downwards and thereby bias the lever411into the locked position where the lock pin engages in the detents416a,418a. Applying upwards pressure to the actuator portion410pivots the lever411to a released position in which the lock pin429is disengaged from the detents416a,418aand free to slide within elongate slots416b,418b. Alternatively, a biasing member may be positioned between a different portion of the lever411and the housing406,407to bias the lever into a locked or a released position. Any suitable type of biasing device could be used.

FIGS. 42 and 43show the lever411and lock pin429in the released position. When the lever and pin are in the released position, the arm assembly body406is free to slide within the sleeve405between the upper and lower limits, to adjust the height of the arm rest. For example, the arm assembly is adjustable from the lowermost position shown inFIG. 42to the position shown inFIG. 43by pulling or pushing the arm rest403or arm body406upward. When the actuator portion410is released from the position shown inFIG. 43, the spring424biases the lever411back towards the locked position, moving the lock pin429into a detent416a,418ato lock the height of the arm rest as shown inFIG. 44.

The arm rest is adjustable relative to the sleeve405to a plurality of heights corresponding to the number of detents416a,418b. For example, in the embodiment shown the detented grooves416,418each comprise ten vertically spaced notches and the arm rest is movable between ten different heights. It will be appreciated that the sleeve may comprise more or fewer than ten detents to enable adjustment of the arm rest403between more or fewer positions.

To assemble the support assembly402, the lever411and reinforcement plate421are arranged with the lever protrusion427in the reinforcement plate slot425and pinned to the cap member407at pivot407aby pin423. The lever and plate421are then placed in the support body406. The rotation mechanism described above is connected to the cover407before or after attaching the lever411and reinforcement plate421. The cap member407is then screwed to the support body406b. The lock pin is then inserted through the slots in the elongate hollow portion of the arm body406and through a complementary aperture in the lever protrusion427. The inner sleeve portions415,417and mounting plate419are then assembled around the elongate portion of the arm body406so that the two ends of the lock pin429are positioned in the respective detented slots416,418. The inner sleeve portions415,417and mounting plate419are then slid into the outer sleeve415.

The mounting plate419has aligned, threaded apertures420for mounting the sleeve assembly405and thereby the arm support assembly to the chair101,101′. Apertures (not shown) are also provided at the back of the outer sleeve413that are aligned with the apertures420in the mounting plate419to receive fasteners420asuch as cap screws for example. The sleeve assembly405is mounted to the back portion501,501′ of the chair by feeding the cap screws through apertures in the back portion501,501′ from the back of the chair, and into the threaded apertures420on the mounting plate419, effectively clamping the sleeve405between the mounting plate419and the chair back.

The back side of the outer sleeve413is preferably shaped to sit substantially flush against the respective frame member504aof the chair back501. For example, in the embodiment shown, the back of the sleeve419is concave to sit flush with a convex back frame member504a.

It can be seen fromFIGS. 37 to 44that the height adjustment mechanism (other than the actuator portion410) is substantially hidden from view from the exterior of the arm support assembly, thereby providing a pleasing aesthetic for the arm support assembly. That is despite the sleeve assembly405only having a small height relative to the support body406.

In an alternative embodiment, the support402may be a non-height adjustable support and may comprise a single member mountable to the chair101. Alternatively, the support may be height adjustable but not comprise an arm rest that is angularly adjustable and/or adjustable forward-rearward or laterally.

Back Portion

Back Construction

FIGS. 45 to 70illustrate a preferred form back assembly501. The back assembly501comprises a back frame503having side frame members504aand upper504band lower504cframe members defining an opening503a. A support531, which is described in further detail below, is attached to the frame503and suspended across the frame opening503a. A cushion assembly507is positioned in front of the frame503and against a front surface of the support531. One or more staple-receiving members511,512are fixed to a rear side of the frame503for connecting the cushioning portion507to the frame503. An aesthetic cover517is positioned on a rear side of the back assembly to cover the connections between the frame503, the cushioning assembly507, and the staple-receiving member(s)511,512.

A forwardly protruding connecting portion505is connected to the lower frame member504cto connect the back assembly501to the recline mechanism201. The connecting portion505connects to the back support arm203of the recline mechanism described above, enabling the back portion to be reclined relative to the transom. Alternatively, the back support arm203and the connecting portion505of the back frame may be integral. In an alternative embodiment, the back assembly501may be fixedly connected to the transom or seat portion, or may be connected to the transom by way of an alternative mechanism so that recline or movement of the back assembly501is the same as or differs from that described above in relation to the recline mechanisms201,201′.

The back frame503defines a substantially rectangular opening503a. The support531comprises a plurality of spaced apart elongate longitudinally extending straps533and a plurality of spaced apart transversely extending straps535. The longitudinal straps533and the transverse straps535each comprise two opposite end connectors545each having an aperture547. The longitudinal and transverse straps connect to the back frame503by hooks561such that the support531is suspended across the aperture503a, providing a support surface for the cushioning assembly507.

The back frame503and back assembly501are preferably forwardly concave about a vertical axis, and at least a lower portion of the back frame and back assembly are preferably forwardly convex about a horizontal transverse axis, to follow the natural curvature of a user's back.

The cushioning assembly507comprises a front upholstery sheet509a, a cushion508, and a rear upholstery sheet509b. The cushion508is preferably a foam member and may comprise moulded or cut out portions to accommodate part of the back frame503and the attachment hooks561for the support531. The upholstery sheets could be any suitable type, such as fabric, leather, or synthetic leather for example. The front upholstery sheet509ais glued to a front surface of the cushion, and the rear upholstery sheet509bis glued to the rear surface of the cushion. The cushion508is at least as large as the opening503adefined by the back frame503, and is preferably sized to substantially cover a front surface of the back frame503and the opening503a. The cushion508may be slightly larger than the front surface of the back frame503so that the peripheral portion of the cushion508wraps around the edge of the back frame503. The front upholstery sheet is preferably larger than the front surface of the cushion such that the edges of the front upholstery sheet can be wrapped around the sides of the cushion508and partly behind the cushion508.

As best seen inFIGS. 49(a) to (c), a rear surface of the back frame503comprises a plurality of hollow cylindrical protrusions515,516. The upper protrusions515are shallower than the lower protrusions516, to enable the upper frame member504bto be lower profile than the lower frame member504c. The staple-receiving members511,512each comprise a front surface with a plurality of forwardly protruding complementary crush dowels513,514as shown inFIGS. 50(a) to (c). The crush dowels513,514have an outer diameter that is slightly larger than the inner diameter of the hollow projections515,516on the rear of the back frame. To connect the staple-receiving members to the back frame503, the dowels513,514are pushed into the corresponding hollow projections515,516on the frame, deforming at least a portion of each dowel.FIGS. 51(a) and 51(b)illustrate the step of assembling the staple-receiving members511,512to the frame503. In the embodiment shown, the dowels513,514comprise ribs about their periphery. At least some of these ribs are flattened when the dowels513,514are forced into the cylindrical protrusions515,516on the back frame503, forming a tight friction fit between the staple-receiving members511,512and the frame503.

The staple-receiving members511,512and dowels513,514preferably comprise a thermoplastic polymeric material with a lower hardness than the back frame503. By way of example, the staple-receiving members may be formed of polypropylene, and the frame may be formed of 30% glass fibre reinforced PET. The deformation of the dowels513,514is typically a plastic deformation, such that the staple-receiving members511,512cannot be firmly reattached if they are removed. In alternative embodiments, the staple-receiving members511,512could be attached to the frame503by other means, for example using fasteners, adhesive, or other snap-type connections. Alternatively, the frame could receive the staples directly. As another alternative, the front upholstery sheet could be fastened to the frame using any suitable means, such as those described above for example.

The staple-receiving members511,512provide a surface for stapling the cushioning assembly507to the back frame503.FIG. 54shows the attachment of the cushioning assembly507to an upper portion of the back frame503. In the embodiment shown, the front upholstery sheet509awraps around the edges of the cushion508, and behind the back frame503and staple-receiving members511,512. The front upholstery sheet509ais then stapled to the rear side of the staple-receiving members511,512. The staple-receiving members provide a surface that is softer than the back frame503for receiving staples. In an alternative embodiment, the rear upholstery member509bmay also wrap around the edge of the back frame503and be stapled to the staple-receiving members511,512together with the front upholstery sheet509a. Alternatively or additionally the cushion508and/or the rear upholstery sheet509bmay be glued to the front surface of the back frame503.

An aesthetic cover517shown inFIG. 52is attached to the rear side of the back frame503to cover the stapled portion of the front upholstery sheet509a, the staple-receiving members511,512, and the rear side of the back frame. The aesthetic cover517comprises an opening517athat is approximately the same size, or slightly smaller than, the back frame opening503aso that the support531and back upholstery sheet509bare visible from behind the back portion. The opening in the aesthetic cover517also allows portions of the cushioning assembly507and support531to deflect rearwardly beyond the frame503and aesthetic cover517during support of a user.

As shown inFIGS. 52(a) and 53(a), an upper portion of the aesthetic cover517comprises a plurality of upwardly projecting tabs518. The tabs518are for engaging with corresponding recess(es)521on a front surface of the back frame503, as shown inFIG. 53(a). A lower portion of the aesthetic cover517comprises a plurality of forwardly projecting crush dowels519as shown inFIGS. 52(c) and 53(b). Side portions of the aesthetic cover517comprise a plurality of outwardly directed tabs520aand outer projections520b. Corresponding catch features522on the side members of the back frame are receivable in the space between the outwardly directed tabs520aand outer projections520b. A lower portion of the back frame503comprises a plurality of hollow cylindrical protrusions506. The crush dowels519are similar to those described above with respect to the staple-receiving members511,512.

The aesthetic cover517is attached to the back frame503by first positioning the upper portion of the aesthetic cover517relative to the upper back frame member so that the recess(es)521is/are behind the tabs518(FIG. 53(a)), snapping the side catch features522between the side tabs520aand projections520b(FIGS. 53(c) and 53(d)), then pressing the crush dowels519into the respective hollow protrusions506on the back frame (FIG. 53(b)), deforming the crush dowels519.

The ‘high back’ back portion501′ will be formed in the same way as the back portion501. However, the upper portion of the back frame503will have a ‘blade’ above the opening, which will support the upper end of the cushioning assembly. The cushioning assembly may have a pocket or similar to receive the blade to assist with mounting the cushioning assembly to the blade of the frame.

Moulded Support

FIG. 70is a rear view of a preferred form chair showing the support531supporting the cushioning assembly member507in the back portion501. The support has the appearance of a plurality of individual longitudinal straps533overlaid over a plurality of individual transverse straps535. While a support comprising a plurality of individual straps has aesthetic advantages, such an arrangement presents a number of assembly and performance disadvantages compared to a one-piece moulded support. Individually attaching many separate straps to a frame is more labour intensive and, where the straps are different lengths presents difficulties in ensuring the straps are in the correct order and orientation. In use, parallel straps are susceptible to twisting or to moving relative to each other, losing the aesthetically appealing grid arrangement.

FIGS. 55 to 70show a preferred form moulded support531for attaching to the frame503to form the support shown inFIG. 70having the appearance of individual straps.

FIGS. 55 to 60, 64(a) to (f), and65(a) and (b) show the support531as moulded. The moulded support531is substantially flat and comprises a plurality of elongate longitudinal straps533and a plurality of elongate transverse straps535. The transverse straps535form a first layer, and the longitudinal straps533overlap with the transverse straps535to form a second layer that overlies the first layer. Integrally moulded joiner members536connect the transverse and longitudinal straps535,533and are positioned at the overlapping portions of the straps533,535. Preferably each longitudinal strap is attached to each transverse strap by the joiner members536.

In the as moulded form, the longitudinal and transverse straps533,535preferably have substantially the same cross-sectional width and thickness, at least in the unnecked regions. By way of example, as shown inFIGS. 65(a) and (b), the straps may have a width WUT, WUL in the unnecked regions of 12 mm, and may have a depth of about 1 mm along their necked and unnecked regions. Alternatively, the longitudinal straps may have different cross-sectional dimensions to the transverse straps if different properties are desired in the longitudinal direction to the transverse direction, or if a combination or differently sized straps are desired for aesthetic reasons.

The lengths of the longitudinal straps533may vary to fit a frame503with non-parallel upper and lower frame members, or to accommodate differing degrees of curvature in the longitudinal straps533in the assembled form. Similarly, the lengths of the transverse straps535may vary for the same reasons with respect to the side members of the frame.

The transverse straps535and the longitudinal straps533may be evenly spaced, or the spacing between adjacent straps may vary. In the form shown, the transverse straps are spaced more sparsely towards the upper portion of the support531and are spaced closer together in the portion of the support that corresponds to the lumbar portion of the chair back portion. The support will be less compliant where the straps are closer together, to provide a greater level of support.

The joiner members536, best seen inFIGS. 64(a) to 64(f) and 66(a) to 66(f), are preferably elongate in the transverse direction. In one embodiment, as moulded, the joiner members measure 18.5 mm in the transverse strap direction, 1.0 mm in the longitudinal strap direction, and 2.0 mm deep (to form a gap between the straps of 2.0 mm). The joiner members536project from a front face of the transverse straps535and connect to a rear face of the longitudinal straps533.

Both the transverse and longitudinal straps are necked on either side of each joiner members536by way or notches or recesses in the sides of the straps. In the form shown, the transverse straps535comprise necked regions539that comprise recesses extending substantially the length of the joiner members536. By way of example, the necked regions may have a length LNT of 17.9 mm, and the width WNT of the transverse strap between the recesses may be 10.0 mm, as shown inFIG. 65(a).

The longitudinal straps533comprise necked regions537that, in the form shown, comprise notches. The necked regions as moulded, are longer than the thickness of the joiners536but, as moulded, are smaller than the width of the respective transverse strap535. The necking539on the transverse straps535is shallower than the necking537on the longitudinal straps533. By way of example, the width WNL of the necked regions between the notches may be 9.4 mm, and the notches may each have a length LNL of about 4.1 mm.

The dimensions of the necked areas are selected to allow the strap to have substantially parallel sides after it has been relaxed post-strain orientation, as described in further detail below. The configuration shown inFIGS. 65(a) and 65(b)is one example configuration for straps that will be stretched to 450% of their as-moulded lengths to achieve strain orientation. The ratio of the two width dimensions will increase or decrease depending on the intended stretching percentage.

FIG. 67is a view similar toFIG. 65but showing alternative exemplary dimensions of one of the neck areas. In this embodiment, the dimensions LNT′, WUT′, WNT′, WUL′, and WNL′ are the same as the respective dimensions LNT, WUT, WNT, WUL, and WNL described with reference toFIG. 65. In this embodiment, LNL′ is a shorter dimension of 3.5 mm compared to the 4.1 mm of LNL ofFIG. 65. This version has radiuses LR of about 1.25 mm in the region where the necked area537meets the straight sides of the longitudinal strap533. The larger radiuses further assist with obtaining substantially parallel sides in the strap533after the strap has been relaxed post-strain orientation. In this embodiment, each strap has a main body depth of about 1.5 mm along the necked and unnecked regions, and the elongate ribs extending along the straps may each have an additional depth of about 0.5 mm. Post-strain orientation, the main body depth of each strap, excluding the elongate rib, will be about 1.0 mm.

The selected ratio for the transverse straps in these embodiments, is 0.833 (10/12=0.833). If the stretching percentage was to increase then the ratio of the necked width WNT to the strap width WUT would decrease. For example, if the stretching percentage increased to 600%, the necked width WNT might be reduced to 8.7 giving a ratio of 0.725 (8.7/12). Alternatively, if the stretching percentage was to decrease the ratio of necked width WNT to strap width WUT would increase. For example if the stretching percentage decreased to 400%, the necked width WNT might be increased to 10.2 giving a ratio of 0.85 (10.2/12).

The same principle applies to the necked area on the longitudinal straps with the dimensions shown being intended for the strap to have substantially parallel sides after relaxing following from stretching to 450%. The selected ratio for the longitudinal strap for an elongation to 450% is 0.783 (9.4/12).

The other dimensions (necked region lengths LNT which in this embodiment=17.9 mm and LNL which in this embodiment=4.1 mm) are related to the dimensions of the joiner itself.

The elongate ribs shown on the front surfaces of the straps inFIG. 63aid stretching and strain orientation, and aid moulding material flow where the joiner meets the straps.

It will be appreciated that the configurations and dimensions of the joiner members, straps, and necked regions may vary without departing from the scope of this aspect of the invention.

The support531can be moulded using any suitable method known to a person skilled in the art. By way of example, the support could be injection moulded using the method described in our PCT publication number WO 2009/126051, and the contents of that specification are incorporated herein in their entirety by way of reference. As the preferred form support doesn't have the fine members described in that publication, the support could alternatively be moulded using more conventional moulding parameters.

The support531is moulded from one or more materials that are suitable for strain orientation. Examples of suitable materials include some of the HYTREL materials available from Du Pont. In an as-formed HYTREL article, the polymer chains in the material are relatively random. By stretching the article, the polymer chains become relatively aligned. That phenomenon is strain orientation. Strain orientation changes the material properties. Typically, the material becomes stronger and more elastic; that is the elastic limit is increased in comparison to the as-formed material. Additionally, the article generally lengthens in the direction of stretching and reduces in cross-section.

In the preferred form, the material is a thermoplastic polyester elastomer. Preferably, the thermoplastic polyester elastomer is a block copolymer comprising a hard (crystalline) segment of polybutylene terephthalate and a soft (amorphous) segment based on long chain polyether glycols. Preferably, the thermoplastic polyester elastomer resin is selected such that the article formed by the moulding method, once fully cured and prior to strain orientation, has a hardness in the range of about 30D to about 55D when tested in accordance with ASTM D2240. More preferably, the thermoplastic polyester elastomer resin is selected such that the article has a hardness in the range of about 30D to about 46D, more preferably in the range of about 35D to about 45D, preferably in the range of about 36D to about 44D, more preferably in the range of about 37D to about 43D, more preferably in the range of about 38D to about 42D, more preferably in the range of about 39D to about 41D, most preferably about 40D.

The thermoplastic polyester resin is preferably one of HYTREL 4069, HYTREL 4556, HYTREL 5526, HYTREL 5556, HYTREL 3078. Most preferably, the resin is HYTREL 4069. The resin may additionally include stabilisers and/or additives to achieve desired properties, for example to improve its resistance to UV light, fire, heat aging, moisture, and/or to make the resin a suitable colour.

The moulded article of the present invention could be formed from any other resins having suitable properties.

The moulded support ofFIGS. 55 to 60is then stretched in both directions as represented by arrows SL, ST to form the elongated support531shown inFIGS. 61 to 63 and 70. In this elongation step, the straps533,535are each stretched SL, ST in their longitudinal direction to lengthen the straps. This elongation causes strain orientation of the material in the straps, as well as in the joiner members536. There is less strain orientation in the necked regions537,539of the straps adjacent the joiner members536, due to the increased material thickness and the resulting reduction in elongation. When the straps are fully stretched, the regions537,539are the widest parts of the straps. As the support is relaxed, the sides of the straps relax to be substantially parallel along their lengths, including in regions537,539. The dimensions of the stretched support during this step are greater than the dimensions of the frame that the support is to be attached to. That is, the longitudinal straps533are stretched SL to a length greater than the distance between the upper and lower portions504b,504cof the frame, and the transverse straps535are stretched ST to a length greater than the dimensions between the frame side members504a.

Preferably, the stretched length of the straps is between about 4 and about 5 times the as-moulded dimension of the straps, and preferably about 4.5 times the as-moulded dimension. Each strap is preferably stretched by proportionally the same amount. That is, the straps might each be stretched to 450% of their initial moulded length, for example. That ensures that any straps that are moulded to have the same cross sectional dimensions but different lengths, will also have substantially the same cross sectional dimensions in their stretched form, and the proportional difference in length between the straps will be maintained. The elongated straps will therefore also have the same strain orientation and properties despite their differing lengths. Alternatively, if different properties are desired for different straps, for example if more compliance is required at different points in the support, the straps may be elongated to different extents.

The straps may be elongated one at a time. Alternatively all of the longitudinal straps533may be elongated together, followed by all of the transverse straps, or conversely all of the transverse straps535may be elongated together, followed by all of the longitudinal straps533. As another alternative, all of the longitudinal and transverse straps may be elongated simultaneously.

After the straps are elongated, the tension applied to the straps is released and the straps relax back down to an un-tensioned state.FIGS. 61 to 63 and 66show the support531in the relaxed state. Due to the alignment of the material in the straps, the length of the relaxed straps is longer than the initial length of the straps in their moulded form. In the relaxed state, the dimensions of the stretched support during this step are smaller than the dimensions of the frame that the support is to be attached to. That is, the longitudinal straps533are shorter than the length between the upper and lower frame members, and the transverse straps535are shorter than the dimensions between the frame side members.

As can be seen inFIGS. 61, 62, and 66, in the post-elongation relaxed state, the sides of the transverse straps535are parallel, and the sides of at least the portions of the longitudinal straps533that are visible from the transverse strap side of the support, are parallel. This gives the appearance of individual straps from behind the back portion of the chair. Preferably, the sides of the longitudinal straps are parallel along their entire lengths. During elongation of the straps, the width of both the necked portions of the straps and the unnecked portions of the straps decrease. However, the reduction in width is greater in the unnecked portions due to greater strain orientation. This compensates for the smaller reduction in width of the necked portions such that the width of the necked portions is substantially the same as the width of the unnecked portions post-strain orientation.

The necking539on the transverse straps535is has a more gentle curvature than the necking537on the longitudinal straps533. It is desirable that the joiner members536are oriented so that the necking in the longitudinal direction of the joiner members536is on the transverse straps535that form the rearmost layer of the support531. This is because after strain orientation, the edges of the straps may not be perfectly parallel in the necked regions537,539adjacent the joiner members536. Any difference in the width of the strain oriented straps in the necked regions tends to be less pronounced with the more gently-curved necked regions. Therefore, it is desirable that the straps with the more tightly curved necked regions are the straps that form the front layer of the support, such that any irregularities in the widths of those straps at the necked regions are obscured by the rearmost straps535from behind, and by the cushioning assembly from the front.

In an alternative configuration where the support531is uncovered to provide an exposed occupant supporting surface in use and is visible from the front portion of the chair, the support could effectively be reversed so that the transverse straps535with the more gentle curvature necking are positioned in front of the longitudinal straps533. Alternatively, the longitudinal straps may be positioned in front of the transverse straps, but the joiner members536may be reoriented so they are elongate in the longitudinal direction, and the longitudinal straps may be provided with the more gentle curvature necking.

Preferably, the post-stretching relaxation lengths of the straps RL, RT is between about 1.5 and about 2.7 times the as-moulded dimension, preferably about 2.1 times the respective as-moulded strap lengths IL, IT. Following strain orientation, both the transverse and longitudinal straps will be longer than prior to strain orientation, and will have a smaller cross-section, both in a width and depth direction. For example, the depth of the straps may reduce from 1.5 mm to 1.0 mm. This is evident from the figures by the increased distance between the transverse and longitudinal straps. That is, the lengths of the SL, ST straps will be greater than the initial lengths IL, IT, and the strap cross-sections will be smaller than the initial strap cross-sections. The post-stretching relaxation lengths RL, RT will be smaller than the lengths of the stretched SL, ST straps, but greater than the initial lengths IL, IT. The post-stretching relaxation strap cross-sections will be between the initial strap cross-sections and the stretched strap cross-sections.

In the preferred form shown, the as-moulded length of the longest longitudinal strap533is about 255 mm. That is stretched out to 1147.5 mm, but could be stretched any suitable amount relative to its starting length, such as between about 4× and 9× its starting length. Similarly, in the form shown, the as-moulded length of the longest transverse strap535is about 210 mm. That is stretched out to 945 mm, but could be stretched any suitable amount relative to its starting length, such as between about 4× and 9× its starting length. The longest longitudinal strap is then relaxed to 519 mm, and the longest transverse strap is relaxed to 426 mm. The relaxed lengths (and therefore the initial moulded lengths and the extent of stretching) will vary for different frame configurations or different desired final product tensions.

The sizes of the joiner members536also change due to the strain orientation that occurs when stretching the longitudinal straps533and the elongate straps535. For example, the joiner members536may initially measure 18.5 mm long, 1.0 mm wide, and 2.0 mm deep (the dimension between straps), and may measure 28.5 mm long, 0.8 mm wide, and 1.8 mm deep after elongation. These width and depth measurements are taken through the centre of the joiner members. These are values at the centre of the joiner members, as the joiner members will have radii where they intersect with the transverse and longitudinal straps for moulding and strength purposes. The joiner members536are strain oriented in both the longitudinal and transverse directions of the support, as a result of stretching both the longitudinal straps533and the transverse straps535. The reduction in width of the joiner members from 1.0 mm to 0.8 mm is less than it would be if the joiner members were not strain oriented in a direction across the width of the joiner members a result of stretching the longitudinal straps533.

While the joiner members are shown as being longer than the width of the longitudinal straps, that is primarily for moulding purposes. The joiner members could be any other suitable shape or size.

Each of the transverse and longitudinal straps comprises an attachment portion545at each of its ends. The attachment portions545are integrally formed as part of the moulding process, and are used to attach the cover to the frame503. In the form shown, the attachment portion545comprises a portion of increased thickness having an aperture547. During stretching of the support531, the attachment portions are generally not elongated to any great extent, so strain orientation does not occur or does not occur to a great extent in the regions of the side attachment features and the material in those portions remains substantially unaligned.

FIGS. 68(a) to 69(d)shows a preferred attachment of the support531to the back frame503. The back frame is provided with a plurality of hooks561that are integrally moulded as part of the frame. In the preferred form, the hooks are spaced apart around the perimeter of the frame and each define a recess between the hook and the frame.

The hooks are provided on a front face of the top frame member504b, on a front face of the side frame members504a, and in a rear face of the bottom frame member504c. The hooks face outwardly from a centre of the back portion, so tension in the support531keeps the support engaged with the hooks in use. At least some of the hooks are provided in recesses563in the frame, with the recesses sized to receive the integral connectors545on the straps. The top and side hooks shown inFIG. 69amay be provided in recesses, or may be surface-mounted as shown.

The support can be mounted to the back frame by inserting the hooks561through the apertures547that are provided on the attachment portions545.

The spacing of the hooks561on the side portions504aof the frame corresponds to the spacing of the transverse straps535. The spacing of the hooks on the upper and lower frame members504b,504ccorresponds to the spacing of the longitudinal straps533. The spacing of the hooks may be even for evenly spaced straps, or may vary if the spacing of straps varies, to provide greater support in one portion of the support. For example, in the form shown, the hooks on the side portions of the frame are more closely spaced near the lumbar region of the back portion, to provide greater support to the lumbar region of a user.

To mount the support to the frame, one end545of each of the transverse straps535is hooked to the frame. The straps are then stretched and the opposite ends of each strap at hooked to the frame. This process is then repeated for the longitudinal straps533which are positioned in front of the transverse straps. Alternatively, the support may be stretched again to or beyond its final dimensions and then connected to the frame. Alternatively, the support could be relaxed onto the frame after expanding the support to strain orientate the straps.

The attachment features could all be provided on a front face of the frame, on a rear face of the frame, or on a combination thereof. Rather than being hooks, the attachment features could instead be projections. However, hooks are preferred to provide a more positive engagement.

In an alternative embodiment, the attachment features on the frame may primarily serve a locating function. The support could additionally be secured to the frame by any suitable means, such as adhesive, fasteners, or welding the support to the frame for example.

In the completed article, the longitudinally extending straps533extend between upper and lower transverse back frame members (or between front and rear seat frame members in the case of a seat), and the transverse members535substantially extend between side frame members. The end result in at least preferred embodiments is a compliant suspended support surface that is pliable, and has good creep resistance and tensile strength.

In the form shown, the straps533,535are substantially flat members. Alternatively, the straps or the moulded support531may have a curved profile formed as part of the moulding process. By way of example only, at least part of the article may have a curved side profile and/or a curved top profile that is formed as part of the moulding process. By moulding the article, it can readily be formed with a three dimensional profile. The contour of the support may be changed by attachment of the support to a contoured frame. For example, in the form shown, the flat moulded support531has a forwardly convex form when it has been attached to the forwardly convex back frame.

The moulded support535has been described above in reference to a support for the back portion of a chair. Alternatively, the moulded support may have other applications. The moulded article may be a support surface for a chair, for example. Preferably, the seat or back frame comprises an opening that is at least partly bounded by frame members, and the method comprises supporting the moulded article from the frame with part of the moulded article extending across the opening, to form a compliant suspended support surface.

If the article is to be used as seat surface rather than a back surface, the thickness of the straps533,535may be greater than mentioned above; for example about twice the thickness mentioned above. Alternatively or additionally, the widths of the elongate straps533,535could be greater than mentioned above; for example about twice the widths mentioned above.

However, the moulded article may be any other suitable type of article. By way of example only, the articles could have application as or in: resistance members in exercise equipment; contact sport helmets; helmet and hat liners; harnesses for backpacks, climbing, safety, paraponting, bungee jumping; support surfaces for baby products including car seats, bouncy beds, baby buggies, cots; trampolines such as springs, mats, minitramps, fire trampolines; other furniture such as dental chairs, aeroplane seating, stadium seating, outdoor furniture; bedding, such as mattress replacements, mattress support surfaces, or pillows; automotive seating, soft tailgates, canopies; hammocks; wake board, snow board, and/or ski bindings; bicycle seats; luggage stowage in transport; hitting surfaces of racquets for sports such as tennis, squash, badminton; wetsuits such as flexible inserts; yachting, such as a catamaran trampoline surface. For such alternative applications, the elongate straps533,535could have significantly different cross-sectional dimensions and lengths from those mentioned above. The extent to which the straps are elongated may also vary. For example, for higher load capacities, the members could have larger cross-sections.

The above describes preferred forms of the moulded support, and modifications can be made thereto without departing from the scope of this aspect of the present invention. For example, the moulded article is described as being a support for the back of a reclining office chair. However, it will be appreciated that such an article can readily be incorporated into different types of chairs, such as dental chairs, meeting seats, vehicle seats, stadium seats, theatre seats, aircraft or other vehicle seats for example. The supporting frame could be modified accordingly, so as to be fixed to the ground or a wall panel for example for a theatre seat.

It will also be appreciated that the principles of this aspect of the invention could be used to provide straps that, in the post-strain orientation form, have a desired shape where the straps are not parallel along their sides. For example, it may be desired to form straps that have specific undulations along their lengths. In such a configuration, the dimensions of the necked regions relative to the unnecked regions will be varied relative to the intended amount of stretching of the straps to cause strain orientation.

For example, rather than being formed as a moulded support531, the straps533,535of the back portion could be separate extruded straps that are strain oriented and connected to the back frame to provide support for the cushioning assembly507. However, the moulded integral support531is preferred, as the joiner members535link the straps533,535to each other, and prevent the straps from moving significantly relative to each other. If separate straps are used, they would need to be separately tethered to each other to prevent excessive independent movement of the straps, such as via adhesive, welding, or the like. Therefore, the preferred form moulded support described above provides significant manufacturing efficiencies over this alternative form.

As another example, the moulded support531is described as being used to support a cushioning assembly on a frame. Instead, the moulded support531could form the body-contacting surface that supports the seated occupant.

Other example modifications to the moulded article and its use are listed in the ‘Summary of the Invention’ section.

Lumbar Support

The chair101,101′ has a lumbar support assembly601arranged with the back assembly501to provide support to the lumbar region of a user's back. A preferred form lumbar support assembly is shown inFIGS. 71 to 84(c). The lumbar support assembly601comprises a lumbar support member or pad605operatively connected to a mounting member603via a carrier611and biasing mechanism607. The mounting member603in turn attaches to the back assembly501,501′ to mount the lumbar support member605rear of a user support surface551of the back assembly using attachment mechanisms609, as will be described below. The biasing mechanism607forwardly biases the carrier611and lumbar support member605.FIGS. 73 to 75show the support assembly in front, top and rear elevation.

In a preferred embodiment, the lumbar support member or pad605comprises polycarbonate, and the mounting member603comprises polypropylene. The other components of the support assembly may comprise other suitable materials such as moulded nylon or steel for example.

The lumbar support member605is slidably mounted on the carrier611for selectively vertically adjusting the position of the lumbar support relative to the mounting member603. The lumbar support member605comprises an elongate guide portion617on a rear side of the lumbar support member. The guide portion may be fixedly or otherwise attached to the lumbar support member605, or may be integral with the lumbar support member605. Preferably the guide portion617is centrally positioned on the support member605. The guide portion617comprises two laterally extending guide flanges619and the carrier611comprises two complementary channels613with open top and bottom ends that slidably receive the guide flanges619, such that the lumbar support member605can slide relative to the carrier611.

The guide portion617comprises a central section having a series of vertically spaced engagement features which, in the form shown, are rearward-facing notches623.FIG. 75is a rear elevation of the support assembly601and shows the series of notches623. The carrier611comprises an engagement member which, in the embodiment shown, is a forwardly projecting detent615that is engageable with the notches623to fix the height of the lumbar support member605relative to the carrier611. The detent615is preferably resilient and resiliently moves relative to the remainder of the carrier611to engage and disengage respective notches as the height of the lumbar support member605is adjusted, such that the lumbar support member605is selectively adjustable relative to the carrier611between a plurality of heights. When sufficient upward or downward force is applied to the lumbar support member605, that will override the forward bias force of the detent615and enable the vertical adjustment to occur. The lumbar support member605comprises two rearwardly-directed grasping handles606at its lower edge to enable a user to easily adjust the height of the lumbar support member605.

Preferably, the detent615and the notches623are arcuate for smooth adjustment and to reduce noise between the detent615and notches623during height adjustment of the lumbar support member605. Alternatively, the notches623and detents615may be other shapes, for example they may comprise angled surfaces.

In an alternative embodiment the carrier611may comprise an engagement feature comprising a notch on a moveable member, and the engagement features on the support member605may comprise a plurality of protrusions for engaging the notch. It will be appreciated that the carrier611may have more than one engagement feature to engage in the plurality of engagement features on the support member605. Similarly, it will be appreciated that instead of flanges and a channel, the lumbar support member605and carrier611may comprise alternative complementary guide features. For example, the carrier611may comprise lateral guide projections and the lumbar support member605may comprise complementary channels or slots for receiving those projections.

The section views ofFIGS. 76, 77(a), and77(b) show the assembled biasing mechanism607according to a preferred form embodiment. In that embodiment, the biasing mechanism607comprises an intermediate member625operatively connected to the mounting member603and the carrier611. The intermediate member625is preferably pivotally connected to the mounting member603at a first pivot631,633and pivotally connected to the carrier611at a second substantially parallel pivot626,627via a pin629. In the embodiment shown, the pivot633on the mounting member603is provided in three protruding tabs. Alternatively two or more than three tabs may be provided.

A first biasing member639is arranged between the mounting member603and the intermediate member625for biasing the intermediate member angularly away from the mounting member603. A second biasing member641is arranged between the detent615and the intermediate member625for angularly biasing the detent615away from the intermediate member625and into engagement with the notches623. The section view ofFIGS. 77(a) and 77(b)are taken through the centre of the detent615and shows the second biasing member641biasing the detent into engagement with one of the notches623.

Preferably, the first and second biasing members639,641are oppositely oriented torsion springs, each having two angled legs. The first torsion spring639is preferably mounted about the first pivot631of the intermediate member, with a first leg639acontacting the mounting member603and a second leg639bcontacting the intermediate member625. The second torsion spring641is preferably mounted about the pivot pin629, with a first leg641aof the second torsion spring641contacting detent615on the carrier611and a second leg641bcontacting the intermediate member625.

The biasing mechanism607further comprises two link arms635each having a first end635apivotable about the pivot626,627between the carrier611and the intermediate member625at pivot pin629. The first ends635aof the link arms comprise apertures for receiving the pin629. The two link arms635each have a second end635bpivotally and slidably mounted in a slot637on the mounting member603. The slot637is preferably perpendicular to the pivot631between the intermediate member625and the mounting member603, such that the second ends635bof the link arms635can move towards or away from the pivot axis631as the intermediate member625pivots relative to the mounting member603. The link arms635limit movement of the intermediate member away from the mounting member due to the preload. In an alternative embodiment, the link arm second ends635bmay be pivotally attached to the mounting member603and slidable relative to the intermediate member625.

The biasing mechanism607resists rearward movement of the lumbar support member605as a user leans into the back portion501,501′ of the chair. Upon application of rearward force to the lumbar support member605, the biasing mechanism607resists rearward movement of the detent615toward the mounting member603more than it resists rearward movement of the carrier611toward the mounting member603. The second biasing member641acting on the detent615biases the detent into engagement with the notches623and causes the engagement between the detent and an engaged notch to increase upon rearward movement of the lumbar support605.

The section views ofFIGS. 78(a) and 78(b)show the support member in a rearward position, with the detent615biased further into engagement with a notch623. The increased engagement means more force is required to slide the lumbar support member605relative to the carrier611when rearward force is applied to the support member605. This ensures the lumbar support member605is less likely to inadvertently move relative to the carrier611while a rearward force is being applied to the lumbar support member605such as during support of the lumbar region of a user in the chair. This is particularly useful with a highly compliant back portion501,501′, where an occupant can readily ‘sink in’ to the back portion and could inadvertently apply a downward force to the lumbar support member605as well as a rearward force.

In addition to resisting rearward movement, the biasing mechanism607described above and shown in the accompanying drawings enables the lumbar support member605to tilt relative to the mounting member603. In an alternative embodiment of the lumbar support assembly, the biasing mechanism may bias the detent away from the mounting member603without enabling the lumbar support member605to be tilted. For example, the carrier611may be movable or slidable horizontally towards the mounting member603, but not angularly tiltable. In such an embodiment, the biasing mechanism may comprise a biasing device such as a spring arranged directly between the mounting member603and the detent615or other engagement feature on the carrier611. A feature636(FIG. 72) on the mounting member603limits rearward motion of the biasing mechanism607by stopping the intermediate member625.

In the embodiment shown, the first and second pivots631,629of the intermediate support member625are substantially horizontal to allow the support to tilt up and down to conform to the angle of a user's back as they move in the chair. In an alternative embodiment, the pivot axes may instead be substantially vertical, for example, to enable the lumbar support member605to tilt sideways to conform to the back of a user twisting in the chair.

FIG. 79shows the lumbar support member605adjusted to a high vertical and biased forward position with no rearward load applied to the lumbar support member605.FIG. 80shows the lumbar support member605in that arrangement tilted upwards upon application of a rearward force to a central or upper portion of the lumbar support member. It can be seen that the detent is biased further into engagement with a notch623when the upper end of the lumbar support member605is tilted rearward.FIG. 81shows the lumbar support member605adjusted to a low vertical and biased forward position with no rearward load applied to the lumbar support member605.FIG. 82shows the lumbar support member605in that arrangement tilted downwards upon application of a rearward force to a central or lower portion of the lumbar support member.

The shape of a preferred form lumbar support member605can be seen in plan view inFIG. 74and section views inFIGS. 76 to 82. The lumbar support member605is forwardly concave in horizontal section, to curve around the back of a user, and forwardly convex in vertical section to accommodate rearward curvature of a user's back. An elongate substantially vertical recess605′ is provided in a central region of the lumbar support member605, to provide clearance for a user's spine.

The mounting member603positions the lumbar support member605behind a rear part551of the user support surface of the back portion501,501′. In the absence of a rearward load on the back portion501,501′ of the chair, the lumbar support member605is spaced behind and out of contact with the rear part551of the user support surface back portion501,501′. The spacing is sufficiently small that upon application of a rearward force to the user support surface when a user leans into the back portion501,501′, at least a part551of the back portion flexes rearward relative to the back frame503to contact the lumbar support member605. The lumbar support member605provides support to the lumbar region of the user's back by providing additional resistance to rearward movement in the lumbar region.

In the form shown, the mounting member603is a rigid beam and is preferably curved, but alternatively may be u-shaped, for example. The ends of the mounting member603attach to the side members504aof the back frame503so that the mounting member603extends rearwardly from the frame. In the embodiment shown, the mounting member603comprises two attachment mechanisms609at each end for attaching the mounting member to the frame side members504a.

Components of the preferred form attachment mechanisms609are shown in the exploded view ofFIG. 72, and in more detail inFIG. 83. The method of using one of the attachment mechanisms609is shown inFIGS. 84(a) to 84(c). Each attachment mechanism609comprises a lock shuttle651, a first lock member653with lock hook(s)653ahaving lock projections653a′, a second lock member655with lock pin(s)655a, a guide pin657, a lock slider659, and a lock retainer cover661. The first lock member653could have one, two, three, or more lock hooks, with the second lock member655having a corresponding number of lock pins655a. A lock mechanism channel663with lower and upper horizontal guide ribs663a,663bis provided in the front face of the mounting member603toward each end of the mounting member.

The lock mechanisms609are selectively moveable between a retracted unlocked position in which they do not project significantly, or at all, beyond the ends of the mounting member603, and a projecting locking position where they project beyond the ends of the mounting member603to attach the mounting member603to the frame side members504a. The lock slider659is provided with a suitable region for grasping, such as a forwardly directed projection660for example, to enable a user to actuate the locking mechanism.

In the assembled mounting member/locking mechanism, the lock shuttle651is positioned in the lock mechanism channel663. The lock shuttle651is slidable vertically between the lower and upper horizontal guide ribs663a,663b, but is not slidable horizontally. The lock shuttle has rearward channels651bthat engage with vertical ribs663cin the channel to enable the vertical sliding movement of the shuttle.

The first lock member653is positioned in front of the shuttle, with its lock hook(s)653adirected toward the end of the mounting member603. The second lock member655is positioned in front of the first lock member, with its lock pin(s)655adirected toward the end of the mounting member. A protrusion655bon the second lock member655is positioned inwardly along the beam from a protrusion651aon the shuttle, to act as an inhibitor to outward movement of the second lock member655. The guide pin657extends through the aligned slots in the second lock member, first lock member, and lock shuttle. The lock slider659is positioned in front of the second lock member, and has rearwardly projecting walls that surround the first lock member and second lock member. The head of the guide pin657is positioned in a cavity659ain the lock slider659, which is preferably vertically elongate to enable vertical movement of the guide pin657relative to the lock slider.

The lock retainer cover661is positioned in front of the lock slider659, and has walls that generally surround the other components of the locking mechanism. The lock retainer cover661is fixed to the mounting member603via any suitable means, such as clips, adhesive, and/or ultrasonic welding for example. The lock retainer cover keeps the lock mechanism assembled with the mounting member603.

The assembly at each end of the mounting member603will be substantially the same, with the components being mirror images of each other.

It can be seen that the lock shuttle651has a substantially linear and substantially horizontal channel652. The first lock member653has a channel654that has an inner angled portion to initially extend outwardly and upwardly from its innermost end, and then has a substantially linear and substantially horizontal portion. The second lock member655has a channel656that initially extends substantially linearly and substantially horizontally outwardly from its innermost end, and then has an outer angled portion that extends outwardly and upwardly. The guide pin657extends through the channels652,654,656as discussed above.

To attach the mounting member603to the frame side members504a, the mounting member603is placed behind the back support531and generally aligned with locking apertures or recesses665in the frame side members504a. The ends of the mounting member603are provided with locator features604to locate the ends of the mounting member in a desired position relative to one of the transverse straps553. The recesses665are provided with engagement shoulders667. The lock sliders659are initially in their innermost positions so that the lock mechanisms609are in their retracted unlocked positions as shown inFIG. 84(a). The lock shuttle651will be in its lowest vertical position in the lock mechanism channel663in the mounting member603.

During initial outward movement of the lock sliders659, the guide pins657are located in the inner angled portions of the slots654of first lock members653and slide along the horizontal portions of the slots656of the second lock members. The first lock members653move outwardly so that their lock hooks653aare positioned in the recesses665. The engagement of the protrusion651aon the shuttle with the protrusion655bon the second lock member will inhibit or prevent outward movement of the second lock member655during initial outward movement of the first lock member653. There is sufficient clearance between the lock hooks653aand the entrances to the recesses665that the lock hooks653acan be clear of the engagement shoulders667, but then manually moved down into position behind the shoulders to the position shown inFIG. 84(b).

Further outward movement of the lock sliders659causes the guide pins657to be located in the angled outer portions of the slots656in the second lock members655, and to slide along the linear horizontal portion of the slots654in the first lock members653. As the guide pin657is lifted in the slots654,656, the guide pin also lifts the shuttle651in the lock mechanism channel663, so that the protrusions651a,655bare disengaged and the second lock member can move outwardly. The vertically slidable shuttles651also assist with avoiding binding of the guide pins657in the slots. The lock pins655aextend beside the the lock hooks653a, to the position shown inFIG. 84(c). The lock projections653a′ are positioned outwardly of the engagement shoulders667. There is insufficient clearance between the lock pins655aand lock hooks653aand the entrances to the recesses665, for the lock projections653a′ to move sufficiently to clear the engagement shoulders667. The mounting member603is thereby attached to the back frame.

To remove the mounting member603from the frame, the process is reversed. In particular, the user will move the lock sliders659inwardly which will initially retract the second lock members655so that the lock pins655amove away from the lock hooks653a. The mounting member603can then be moved vertically so that the lock projections653a′ can clear the engagement shoulders667. Further inward movement of the lock sliders659will cause the lock hooks653ato retract from the recesses665so that the mounting member603can be removed from the frame.

It will be appreciated that the mechanism could readily be inverted, so that the lock hooks653aare upper members with upwardly directed lock projections653a′, and the lock pins655aengage the undersides of the lock hooks653a.

The lumbar support assembly is retrofittable to the back portion501,501′ by an end user, and is preferably able to be removed from the back portion by the end user.

Rather than using the attachment mechanism described above, alternatively the mounting member603could be mounted to the frame side members504ausing clips. The clips may be u-shaped clips that wrap around the front side of the frame503. To attach the mounting member603to the back frame, the mounting member is arranged behind the rear part551of the user support surface of the back portion, with the attachment clips in front of the frame and aligned with the side frame members. The mounting member603is then pulled rearward relative to the frame until the attachment clips snap into engagement with the frame. Suitable apertures would be provided in the side frame members504afor receipt of the clips.

In alternative embodiments, the mounting member603may be attached to the back frame503using other attachment methods. For example, the mounting member603may be attached to the frame using fasteners such as screws, adhesive, or welded to the frame. Alternatively, the mounting member603and the back frame503may be integral. Preferably the mounting member603is fixed relative to the side members504a, but alternatively the mounting member603may be adjustable relative to the frame.

Rather than a lumbar support assembly as described above, embodiments of the support assembly could be used to support other portions of the back or body from a back portion of a chair, for example as a head or neck support assembly positioned on a higher region of the back portion501′.

The above describes preferred forms of the present invention, and modifications can be made thereto without departing from the scope of the present invention. For example, the preferred form features are described and shown with reference to a reclining office chair. However, it will be appreciated that many of the features can readily be incorporated into different types of chairs, such as meeting chairs, vehicle chairs, or theatre chairs for example. The supporting frame could be modified accordingly, so as to be fixed to the ground or a wall panel for example for a theatre chair.

Additionally, a number of the features described herein can be incorporated into chairs having different features. They need not all be incorporated into the same chair.

Other example modifications are listed in the ‘Summary of the Invention’ section.