GB2428966A

GB2428966A - Seat with pivoting backrest and coupled locking means therefor

Info

Publication number: GB2428966A
Application number: GB0516597A
Authority: GB
Inventors: Christopher David Manifold
Original assignee: TRAKKER PRODUCTS Ltd
Current assignee: TRAKKER PRODUCTS Ltd
Priority date: 2005-08-12
Filing date: 2005-08-12
Publication date: 2007-02-14
Anticipated expiration: 2025-08-12
Also published as: GB2428966B; GB0516597D0

Abstract

A collapsible framed seat has first and second pivot assemblies (204 and 205). The seat structure contains a releasable locking member (209). The seat may have a squab (200) and a backrest (201). The squab and the backrest may have frame of rigid elongate material (202 and 203). A U shaped coupling means is provided to connect the locking means together (Fig 7 and 9) and may be a rod or a wire. A handle (210) is connected to the coupling means to enable a user to simultaneously unlock and reposition the backrest with respect to seat squab. A spring bias means (700 Fig 7) may be provided to urge the locking means into engagement. Lifting the handle raises the locking means out of the notch allowing pivot movement. The releasable locking means may have a motor (1401 Fig 14). The seat may be a collapsible, camping or angling chair. The seat may have a locking means in the form of an elongate rod engaging with a plurality of locations (Figs 5,7,10 and 11) or via a cable ( Fig 13).

Description

IMPROVEMENTS TO SEATS, BED CHAIRS AND THE LIKE

Field of the Invention

The present invention relates to improvements to the adjustability of back- rests of seats, bed chairs and the like. More particularly, but not exclusively, the invention relates to improvements to the adjustability of backrests of collapsible seats, bed chairs and the like of the type including a frame.

Background to the Invention

Seats and bed chairs of the type used by anglers are known. For example GB 2344510 in the name of Fox International Design Limited and GB 2219934 in the name of CBM Display Group Limited both disclose bed chairs of the type used by an angler. Bed chairs of the type disclosed in the aforementioned published documents typically comprise a frame of rigid elongate material and a seating member attached to the frame. The seating member typically comprises a sheet or membrane or some other flexible construction on which a person sits or lies. In such a framed construction the seating member is normally attached to the frame by means of an elasticated cord that extends between the frame and the seating member. The cord may be threaded through eyelets in the seating member and then wound around portions of the frame to securely attach both components together.

With known bed chairs of the type disclosed in GB 2344510 and GB 2219934 the frame is normally divided into a seating portion upon which a person sits and a backrest portion, both portions being U-shaped and both connected together about an adjacent edge such that the backrest portion pivots relative to the seating portion. The known pivotal arrangement is schematically illustrated in Figs. 1A and 1 B and is configured such that the backrest portion 100 may be adjusted with regard to its angle of inclination from the plane of the seating portion 101. In the known pivotal arrangement each side of the seat/bed chair is associated with a pivotal attachment 102. The known pivotal attachment comprises a serrated or toothed circular portion 103 located at an end of the U- * * * S *SS * * * S * * * S S * S * S S 555 * * S. S S S * 55 S * S * * * - -- shaped backrest 104 and configured to engage with a similar toothed or serrated portion 105 located on a larger hand-wheel locking nut. By loosening the locking nuts on both sides of the seat/bed chair an operator is able to rotate the backrest about the pivotal attachments so as to position the backrest at a desired angle of inclination relative to the seating portion. Once the desired angle is obtained the operator then tightens the hand wheel nuts on each side of the seat/chair so as to securely engage the toothed/serrated surfaces. However a problem exists with this mechanism for adjusting the backrest in that the operator has to separately adjust the respective pivotal attachments located at opposite side of the chair.

Due to the configuration of the mechanisms for adjustment and the locations thereof (towards the sides of the seat) the process for performing a required adjustment is both time consuming and frustrating to the user. In particular if the user remains sat on the seat the process can be hindered by virtue of the user actually being sat on the seat. It is therefore a further problem that a user will be inconvenienced to the extent that they decide that it is often simpler to completely remove themselves from the seat to perform the adjustment by attending to the respective mechanisms from each respective side of the seat. The inconvenience can be greater if the user is required to perform the following steps a plurality of times: remove themselves from the seat; and test the angle of inclination by returning to the seat.

Further types of framed seating structures are also known in the form of so- called "sun-loungers". One such structure comprises a backrest frame and a seating frame that are connected by a pair of ratcheted pivots to enable incremental adjustment of the angle of inclination of the backrest relative to the seating portion. However with this known structure the ratchet mechanism associated with each pivot is configured such that a user is required to bring the backrest into a plane that is substantially parallel with that of the seating portion in order to change the direction in which the backrest may be adjusted. Thus if the backrest is required to be set at a slightly smaller angle of inclination, but the ratchet is set to permit only an increase, then the user has to increase the angle to the full extent (180 ) so as to effect the required reversal of the permitted * * * S *SS * * S S * S S S * * * S S S 515 S S S. S S S S IS I S S S S S S *0 direction of movement as controlled by the ratchet mechanism. Similarly if the permitted direction is towards a smaller angle then the user is required to fold the backrest on top of the seating portion before the ratchet is released so as to reverse the permitted direction of angular adjustment. Thus although such a system permits incremental adjustment of the angle of inclination it greatly inconveniences the user of the sun lounger since effectively the user has to fully open out or close the sun lounger to change the direction of angular adjustment.

The inconvenience is greatest in terms of changing from the mode of reducing angle to the mode of increasing angle since this change requires a user to be completely removed from the seating portion. A further problem associated with such known sun loungers is that the ratchet mechanisms, being made of metal, create a substantial amount of noise during operation and this is known to be undesirable in various environments and in particular in situations concerning the art of fishing.

The above mentioned bed chairs and sun lounger are portable by which it is meant that they are designed for being carried in a collapsed state by a single person. They are therefore collapsible by which it is meant that they may be transformed from a first state whereby they are configured to be used as a seat or bed chair to a second state whereby at least the seating portion is stored in a plane that is substantially parallel to and adjacent to the plane of the backrest portion. In the first state the plane defined by the backrest portion and the plane defined by the seating portion are oriented relative to each other such that the plane of the seating portion is normally transverse to the plane of the backrest portion.

In view of the above there is a need to provide an improved system for enabling collapsible seats/bed chairs to be more readily adjustable with regard to the angle of the back support portion relative to the seating portion.

Summary of the Invention

* * * S **S * S I S * I * I S I S I I S 5*5 5 S

SI S S S S II S

S I S S I I SI

An object of the present invention is to provide a collapsible seating structure, such as an angler's chair or bed chair, that comprises a seating portion and a backrest portion such that the backrest portion may be readily inclined towards or away from the seating portion whilst a person is sitting on the seating structure.

Another object of the present invention is to provide a seating structure that comprises a seating portion and a backrest portion such that the backrest portion may be incrementally inclined towards or away from the seating portion by a single operation whilst a person is sitting or otherwise supported by the seating structure.

Another object of the present invention is to provide a seating structure comprising a frame of rigid elongate material, the frame comprising a seating portion attached at first and second pivotal points to a backrest portion, the seating and backrest portions being inclinable relative to each other about the first and second pivotal points, the seating structure further comprising an engagement member provided respectively at the region of each of the first and second pivotal points and a releasable locking member extending a distance from the region of each of the first and second pivotal points, the locking member comprising means to releasably engage each of the engagement members to thereby releasably lock the backrest portion in position relative to the seating portion.

Yet another object of the present invention is to provide a seating structure that comprises a pivotally connected framed seating portion and framed backrest portion such that the pivotal connection comprises first and second pairs of engagement/locking members controlled by a releasable locking mechanism that couples the operation of both said pairs together whilst enabling the angle of inclination between said seating portion and said backrest portion to be directly increased and decreased from substantially any angle of inclination.

* * * * S..

* S * * S S * S S * * S * S 555 5 * S. S * * S 55 5 * S S S 5 *S According to a first aspect of the present invention there is provided a collapsible seating structure for use by a person, said seating structure comprising a frame of rigid elongate material, said frame comprising a seating portion attached at first and second pivotal points to a backrest portion, said first and second pivotal points each comprising an engagement member configured to engage with or disengage from respective first and second locking members of a releasable locking mechanism to thereby enable the angle of inclination between said seating portion and said backrest portion to be directly increased and decreased from substantially any angle of inclination, said seating structure characterized in that said releasable locking mechanism additionally comprises: coupling means configured to mechanically couple activation of said engagement or said disengagement of said first locking member with said first engagement member and said second locking member with said second engagement member such that said activation is thereby effected substantially simultaneously; and handle means connected to said coupling means and located on one of said portions, said handle means functioning to enable said person to use a hand to effect said activation of said coupling means whilst simultaneously functioning to enable said person to use said same hand to adjust said angle of inclination.

Preferably each said engagement member is mechanically coupled to the other to enable said engagement and said disengagement to be performed substantially by an operator using said releasable locking mechanism to apply a single force from the set comprising a tensile force and a compressional force.

Preferably each said engagement member is mechanically coupled to the other by virtue of said releasable locking mechanism to enable said engagement and said disengagement to be performed substantially from a single location on said structure.

* * * * S..

* . S S * * S S * * S S S S *55 * 5 S. S 5 * S S. * * . . * ** Preferably each said engagement member is configured with means to enable said angle of inclination to be incrementally adjusted.

Preferably a said engagement member comprises a plurality of teeth that are engageable by said respective locking member.

Preferably said seating structure further comprises bias means configured to bias a said locking member in locking engagement with a said engagement member.

Preferably a said engagement member is formed as a wheel-like member, said teeth formed by concave curved regions spaced apart relative to one another at a circumference of said wheel-like member.

Preferably said bias means comprises a helical spring provided in contact with a portion of said backrest portion and said associated locking member.

Preferably said spring is housed within a spring housing connected to said frame of said backrest portion.

Preferably said releasable locking mechanism comprises an elongate member extending between said first and second pivotal points, said releasable locking mechanism substantially being "U"-shaped.

Preferably a region of said releasable locking member is remotely positioned relative to said first and second pivotal points the remotely positioned region being configured as a handle/lever to effect operation of said locking mechanism.

Preferably said releasable locking mechanism comprises a rigid elongate material in the form of a rod. U ***

* * S * S S U S S S S S S S Use S U S. S S U S S. * ._. S * * S. Preferably said releasable locking mechanism comprises an elongate wire.

Preferably a said locking member comprises an end region of said releasable locking mechanism, said end region being elongate and oriented at substantially 90 to the portion of said releasable locking mechanism to which it is connected.

Preferably a said locking member of said releasable locking mechanism comprises a hinge attachment as regards its attachment to the remainder of said releasable locking mechanism.

Preferably a said engagement member is connected to said frame of said backrest portion by a fork comprising a groove portion through which a said locking member passes through, said locking member capable of sliding back and forth within said groove portion to contact said engagement member.

Preferably said releasable locking member comprises an elongate structure aligned in a substantially planar arrangement and positioned such that the plane of said locking mechanism is substantially parallel to the plane defined by said backrest portion.

Preferably said handle means of said locking mechanism is positioned towards one end of said frame of said backrest portion and a said locking member to engage with a said engagement member is positioned towards a second end of said frame of said backrest portion.

Preferably said locking mechanism is substantially located on the rear side of said backrest portion.

Preferably said releasable locking mechanism comprises an electrically powered motor.

* S I S *** * S S S S S S S S * S * * * 5.5 S I S. S S S S ** S - ! * i.

Preferably said structure is comprises at least one collapsible leg assembly.

Preferably said seating structure comprises an angler's seat.

Preferably said seating structure comprises an angler's bed chair.

According to a second aspect of the present invention there is provided a collapsible framed seating structure comprising first and second pivot assemblies, said seating structure comprising a coupled releasable locking mechanism.

According to a third aspect of the present invention there is provided a collapsible framed seating structure pivot assembly comprising: a locking member in the form of an elongate rod; and an engagement means configured to receive and thereby engage with said locking member, wherein said engagement means is provided with a plurality of engagement locations.

Brief Description of the Drawings

For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present invention with reference to the accompanying drawings in which: Figure IA schematically illustrates, in perspective view, a prior art reclining seat/bed chair having a pivotal attachment between a framed seating portion and a framed backrest portion; Figure lB further schematically illustrates, in perspective view, the pivot portion of the prior art reclining seat/bed chair of Figure IA; * * S S *s* * S S S S S S S S * S S S S *SS S S 5 S S S 55 5 -- *S S S S 55 Figure 2 schematically illustrates, in perspective view, a collapsible seating structure as configured in accordance with a preferred embodiment of the present invention, the structure comprising first and second pivotal points each associated with a releasable locking mechanism comprising an elongate rigid actuating member and the structure erected in a form suitable for sitting on; Figure 3 further details, in a perspective view, a first preferred embodiment of one of the pivotal points of the backrest portion of the seating structure of Figure 2; Figure 4 schematically illustrates a cross-sectional side elevation view of the pivot point illustrated in Figure 3; Figure 5 schematically illustrates a further perspective view of the pivot point of Figure 4; Figure 6 schematically illustrates a back elevation view of the releasable locking mechanism and framed backrest portion of the seating structure of Figure 2, the releasable locking mechanism comprising an elongate rigid actuating member; Figure 7 schematically illustrates a back elevation cross-sectional view of the region of the pivot point of Figures 4 and 5 so as to further detail certain hidden components of the releasable locking mechanism; Figure 8 schematically illustrates a further perspective view of the seating structure of Figures 2-7 wherein the angle of inclination of the backrest portion relative to the seating portion has been increased as compared to the angle of inclination depicted in Figure 2; Figure 9 schematically illustrates a further perspective view of the seating structure of Figure 2 wherein the angle of inclination of the backrest portion * S S S **e * * S S S S * * S * S S S S *.S S S *S S S S S 55 S -- 5_S * * S 55 relative to the seating portion has been decreased as compared to the angle of inclination depicted in Figure 2 with the result that the seating structure has been folded into a fully collapsed state; Figure 10 schematically illustrates, in a perspective view, a second alternative preferred embodiment for configuring a pivotal point of a backrest portion of a seating structure as configured in accordance with the present invention, the releasable locking mechanism comprising an elongate rigid actuating member having a hinged portion in the form of a swivel joint or a ball joint; Figure 11 schematically illustrates, in side elevation view, respective third and fourth alternative preferred embodiments for configuring a pivotal point of a backrest portion of a seating structure as configured in accordance with the present invention, the releasable locking mechanism comprising an elongate rigid actuating member associated with a member that may be pushed or pulled depending on the nature of the operating mechanism selected.

Figure 12 schematically illustrates a back elevation view of a further preferred embodiment of a releasable locking mechanism and framed backrest portion of a seating structure as configured in accordance with the present invention, the releasable locking mechanism comprising an elongate actuating member in the form of a cable.

Figure 13 schematically illustrates a cross-sectional perspective view of the region of the pivot point of Figure 12 so as to further detail certain hidden components of the releasable locking mechanism; and Figure 14 schematically illustrates a back elevation view of a further preferred embodiment of a releasable locking mechanism and framed backrest portion of a seating structure as configured in accordance with the present * S S S.55 * 5 5 S S S * 5 5 * S S * * *SS S S 5S S S S S 55 S __. *_S S 5 * Se invention, the releasable locking mechanism comprising an electrically operated actuating member.

Detailed Description

There will now be described by way of example a specific mode contemplated by the inventors. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to

unnecessarily obscure the description.

Figure 2 herein is a perspective view of the collapsible seating structure according to a preferred embodiment of the present invention. The seating structure is portable and is thereby divided into a seating portion 200 upon which a person sits and a backrest portion 201 capable of supporting the back and head of a person seated on the structure. Seating portion 200 is supported from underneath by a rigid frame 202. Frame 202 is configured with three sides such that it has the shape of a planar rectangle. Preferably each of the three sides of frame 202 are made from an elongate, light weight structural member such as a length of tubular steel or aluminium. Similarly, backrest portion 201 is supported by elongate tubular frame 203 defining three sides of a similar sized planar rectangle. Each frame portion therefore has two parallel sides connected via the third side. The parallel sides each define the height of the seating structure backrest, the height being greatest when the two parallel sides extend in a substantially vertical plane.

Backrest portion 201 is pivotally connected to seating portion 200 via first pivotal point (or pivot assembly) 204 and second pivotal point 205, the pivot points being positioned towards one end of the rectangular backrest and seating portions. Both the first and second pivotal points comprise an engagement member 206/207 capable of being releasably engaged by a releasable locking * . * a a..

* * * * a a S * S * a S * a... * a *e a a a a.. a __ _ S_S S 5 mechanism 209. Releasable locking mechanism 209 extends along the frame 203 of the backrest portion from the first and second pivotal points 204, 205, and is substantially parallel to the main plane of the backrest frame portion 203.

Substantially towards an opposite end of the rectangular backrest frame portion 203 relative to the pivotal points 204, 205, releasable locking mechanism 209 comprises handle means 210 provided substantially centrally relative to the width of the rectangle defined by backrest frame portion 203. The seating structure of Figure 2 may also be termed a foldable seating structure in that the backrest portion is configured to rotate about the pivotal points relative to the seating portion such that it can be folded over into a plane that is substantially parallel to and adjacent to that of the seating portion.

The collapsible seating structure that is schematically illustrated in Figure 2 comprises two sets of foldable leg assemblies, each leg assembly comprising two legs. A first leg assembly 211 is located towards the backrest end of seating portion frame 202. Leg assembly 211 is affixed to seating frame portion 202 via suitable respective hinge means 212 mounted at the respective rear ends of the rectangle defined by seating portion 202 in close proximity to the first and second pivotal points 204, 205. The second leg assembly 213 is attached to seating portion frame 202 at the opposite (front) end of the seating frame 202 to leg assembly 211. The leg assembly 213 is mounted via suitable respective hinge means 214 mounted at the respective front corners of the rectangle defined by seating portion 202. Accordingly, the seating structure and in particular the seating portion 200 is capable of being supported on the ground by respective front and rear double leg assemblies 211, 213, a leg thereby being provided within the region of each corner of the substantially rectangular seating portion.

Locating feet, such as the location foot indicated at 215 in relation to rear leg assembly 211, are provided at a ground- engaging end of each leg. Each locating foot comprises a substantially disk-shaped base with a central projection being affixed to the bottom of each leg of leg assemblies 211, 213. Each locating foot is movably connected to each leg to enable the seating structure to be located securely on uneven ground surfaces. In particular a locating foot 215 4. . *.a * * a a a e a 4.

a 4. 4 a a *s - I * * * 0 as a -- ._a a, I. suitably comprises a conventional ball and socket type of movable connecting joint. Each leg assembly is configured to fold about its respective hinge attachments such that the leg assemblies may be stored in a plane that is substantially parallel to the plane defined by the seating frame 202. In use each respective leg assembly may be swung down from the storage/transportation position such that the rectangular leg assemblies each lie in a plane that is transverse and preferably substantially perpendicular to the plane defined by seating frame portion 202. Thus deployment of a leg assembly from the storage/transportation position to the in-use position requires a user of the seating structure to rotate the leg assembly through approximately 90 until the respective hinge mountings lock the leg assembly in position or at least prevent further rotation due to a suitably configured stop.

Referring to Figure 2 it can be seen that seating support portion 200 is configured to support a seating support member 216. Similarly backrest portion 201 is associated with a backrest support member 217. Seating support member 216 and backrest support member 217 suitably comprises an inner foam member of 2cm to 5cm in thickness covered by a suitably durable material that is preferably water resistant so that the inner foam layer does not take in water if the surrounding environmental conditions are such that it is, for example, raining.

Seating support member 216 and backrest support member 217 are releasably attached to respective frame portions 202 and 203 by an elongate flexible material or elasticated cord such as that shown at 218 in relation to backrest support member 217. A plurality of loop type structures 219, 220 are provided on support members 216, 217, on the side communicating with respective frames 202, 203. The loop members are provided such that the elasticated cord 218 is threaded there through to thereby hold the support member to the respective frame. The elasticated cord may be further entwined around the respective frame portion encircling or otherwise enclosing elongate releasable locking mechanism 209.

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* I I U U U * * * . S U * S * p a, .1 S _a *.

Figure 3 herein is a perspective view, Figure 4 herein is a cross sectional side elevation view and Figure 5 herein is a further perspective view of the region of the first or second pivotal points 204, 205 of Figure 2 herein. Each pivotal point comprises an engagement member 206/207. Each engagement member is formed as a drum or wheel like member 300 through which a central axle in the form of a bolt is positioned. For example axle structure 301 associated with engagement member 207 rotatably secures the engagement member in position at a fork 302 which in turn is connected to the tubular frame 203 of the backrest portion via a spring housing 303. The engagement member is thus held in a rotatable position at the fork by a suitable nut and/or bolt.

An annular lip 304 extends around the circumference of drum 300, displaced to one side of the drum towards one of the two fork legs 302. A threaded locating orifice (female) 305 is formed in the annular lip 304 and this is configured to engage with a fixing in the form of a threaded bolt that passes through a portion of seating portion 200 to thereby lock engagement member 207 in a fixed position at seating portion 200 and in particular to the tubular frame 202 of the seating portion. Accordingly, engagement member 207 is not configured to rotate relative to seating portion frame 202 according to this particular implementation of the present invention.

A plurality of concave curved regions or notches are formed in annular lip 304 to provide teeth being defined by troughs such as trough 306 and peaks such as peak 307. The teeth such as tooth 307 are formed over a portion of the circumference of annular lip 304, being angularly spaced about the circumference of drum 300.

In the preferred embodiment illustrated in Fig.'s 2 and 3 releasable locking mechanism 209 is formed as an elongate rod, a portion of which extends parallel to and adjacent to each side along the length of backrest frame portion 203. The releasable locking mechanism 209 is thereby substantially U'-shaped, substantially following the sides of the backrest frame at each side and towards * * I * *i_ e * * * * * 4 I I * (I44 I I Is I I S S j) $ I * IS the top of the backrest. Towards each of the lower ends of releasable locking member 209, a means to releasably engage witheach of the engagement members (206/207) is provided. Thus in relation to engagement member 207, locking member means to releasably engage 308 is provided. According to the specific implementation of the present invention as illustrated in Fig.'s 2 and 3 means 308 is formed from an end portion of the rod-like locking member. Means 308 is suitably configured to extend in a direction that is aligned transverse and preferably perpendicular to the elongate side portions of U'-shaped member 209 such that means to engage 308 is thereby elongate with its main length being oriented in a direction that is perpendicular to the direction defined by a length of either of the two parallel sides of the backrest frame 203. A securing bolt 309, affixed to the end of locking mechanism 209 restricts movement of means to engage 308 in a direction across the width of the backrest portion. A channel or groove 310 is provided in a portion of fork 302 and adjoining spring housing 308 is such that the groove is located above the means to engage 308. Channel 310 is of sufficient width and length to allow means to engage 308 to be raised and lowered relative to the teeth of the engagement member.

Handle means 210 is connected to the releasable locking mechanism 209 and mechanism 209 functions to mechanically couple activation of the engagement or the disengagement of the first locking member with the first engagement member and the second locking member with the second engagement member such that the activation is thereby effected substantially simultaneously. Handle means 210 is located on either the seating portion or the backrest portion. Handle means 210 functions to enable a person to use a hand to effect the activation of the coupling means whilst simultaneously functioning to enable the person to use the same hand to adjust the angle of inclination. In the best mode contemplated handle means 210 is located on the rear side and towards the upper end of the backrest portion since it provides a convenient position from which a person sat may operate the releasable locking mechanism whilst actually remaining seated on the seating structure.

* S S * *** * S * S * * I * * * S S 4 S 555 5 5 S. S S S S 55 S I S S S I * 58 * I 555.

Figure 6 herein is a back elevation view of backrest portion 201 and first and second pivotal points 204, 205 of Figure 2 herein. Releasable locking mechanism 209 extends from the upper end of the rectangle defined by frame 203 substantially towards the lower end, substantially along the length of backrest frame portion 203. Releasable locking member 209 comprises first and second arms 601/602 each extending in-line and parallel to a portion of frame 203 in the direction towards respective pivotal points 204, 205. Substantially half way along the length of the rectangle, defined by frame 203, the rod-like locking mechanism 209 comprises respective bend portions 603/604 above whereby the two arms 601/602 converge inwardly, relative to frame 203, towards the middle of the rectangle defined by frame 203 across its width. Handle means 210 is provided at this mid-region. Accordingly, handle means 210 is positioned towards an opposite end of backrest portion 201 relative to, and remote from, the pivotal points 204, 205. As handle means 210 is positioned remotely from the pivotal points the locking action of the backrest portion relative to the seating portion is controllable without a user having to dismount the seating structure. The user is able to bend their arm over their shoulder and use handle means 210 to effect adjustment of the incline of the backrest. The user is thereby not required to dismount in order to independently adjust the locking mechanism at each pivotal point. This is thereby in contrast to the known reclining seats disclosed in the art such as those of the type illustrated in Fig. I herein.

Figure 7 herein schematically illustrates a back elevation crosssectional view of one of the regions of the pivot portion 204, 205 of Figures 4 to 5 herein.

The dashed lines illustrate concealed components and in particular biasing means 700 in the form of a helical spring. Spring 700 is housed within spring housing 303 located between the lower end region 701 of the tubular frame 203 and the top of the engagement member 207 that is positioned substantially below.

Helical spring 700 abuts against the means to engage 308 of the releasable locking mechanism 209 so as to provide a biasing force onto the end portion of * S S S **S * * S S S S S S S * S * 4 5 555 5 I S. S S * S 55 S * * S S S S 55 S.. S * SS5 S the locking mechanism 209 thereby maintaining means to engage 308 in contact with a trough 306 (between adjacent teeth) of the engagement member 207. A similar helical spring/spring housing and means to engage is provided in relation to the other side of the releasable locking mechanism that is associated with pivotal point 206.

Referring to Figures 6 and 7 herein, in operation to engage and disengage the incline locking mechanism of the present invention, a user, seated on the seat, grasps handle 210 located approximately behind the neck, upper back or head of the person and provides a pulling motion in an upward direction away from the pivotal points as is indicated by upwards pointing arrow 702. The locking mechanism 209 and in particular the means to engage 308 slides upwardly within channel 310 (Figures 3 to 5 herein) of fork 302 so as to disengage from the notch formed by trough 306. By providing a single, that is a mechanically coupled, releasable locking mechanism 209 extending from and substantially simultaneously controlling both said first and second pivotal points a single pulling action will thereby unlock both locking mechanisms located respectively at the first and second pivotal points. Spring 700 compresses in response to the upward movement of means to engage 308 such that a user is required to maintain a force effected by performing an upwards pulling action upon handle 210 whilst pivoting and changing the angle of backrest portion 201 relative to seating portion 200.

When the desired angle of inclination between the backrest portion and seating portion is achieved, via a user grasping handle 210, handle 210 is released wherein each spring 700, in contact with each means to engage 308, forces the ends of the locking mechanism in a direction towards first and second pivotal points 204, 205. Accordingly, each means to engage 308 thereby engages with a notch 306 and sits at a resting position within the concave groove 306 thereby locking in position, at a desired angle of inclination, backrest portion 201 relative to seating portion 200.

* * S * 155 * S S S S S S S I * S S * * 555 S S S. S S S S SI I * 0 5 5 5. 55 *.* I * SSS S The present invention therefore provides a convenient means to adjust and releasably lock the angle of inclination of the backrest via a single handle or lever that is conveniently positioned for a user of the seating structure to operate. In the best mode contemplated the handle 210 is positioned at an upper region of the backrest that is remote from the backrest pivotal points 204/205. A user is therefore not required to place hands or fingers in the region of the pivotal points which is in contrast to prior art devices of the type illustrated in Fig. 's IA, lB.

Thereby injury risks associated with trapped hands or fingers are substantially eliminated by the present invention. Moreover the locking action and unlocking action effected by the releasable locking mechanism 209 and handle 210 is provided by a simple bi-directional movement of handle 210 and mechanism 209 as is generally indicated by double headed arrow 605 of Figure 6. The releasable locking mechanism 209, operated via handle means 210, thus provides a coupling mechanism to couple the activation of (that is, the locking or unlocking of) each respective end portion thereof with the respective engagement members 206/207. Locking member 308 operates in relation to engagement member 207 and a similar arrangement is provided in relation to engagement member 206. Activation of each locking member associated with each end of mechanism 209 is thus mechanically coupled to the other by virtue of mechanism 209 thereby enabling both pairs of locking member/engagement member to be activated substantially simultaneously via the operator performing a single action at a single point using handle means 210. Those skilled in the art will understand that the activation, that is the locking or unlocking, of the respective pairs of locking member/engagement member permits the required angular adjustment to be performed without unwanted noise being generated since in the best mode disengagement involves the respective engagement members being completely disengaged from the locking members.

Figure 8 schematically illustrates a further perspective view of the seating collapsible structure of Figures 2 to 7 wherein the angle of inclination of the backrest frame portion 203 relative to the seating frame portion 202 has been increased as compared to the angle of inclination depicted in Figure 2. The * S S S S S S * S S S S S * S 5 0 * *** S S S5 S S 5 0 55 S * S * S * 5 55 55. S * SSS * increase in the angle means that inclination has been effected by virtue of an angler sitting on the seating structure and bending their arm over the top of backrest portion 203 so as to pull on handle 210 whilst simultaneously forcing backrest portion 203 away from seating portion 202. However in the angular position shown, if the angler decides that the angle of inclination has been adjusted to an incorrect/uncomfortable angle then he or she may pull on handle 210 and pull backrest portion 203 slightly towards portion 202 (that is to the right in the Figure) so as to decrease the angle of inclination. In this way it is convenient for the angler to find a desirable angle of inclination for the particular position that he or she wishes to be positioned in.

Figure 9 schematically illustrates a further perspective view of the seating structure of Figure 2 wherein the angle of inclination of the backrest portion 203 relative to the seating portion 202 has been decreased as compared to the angle is of inclination depicted in Figure 2. The resulting configuration depicted in Figure 9 is such that the seating structure has been folded into a fully collapsed, folded state 901. To achieve this configuration backrest portion 201 has been pivoted towards seating portion 200 using handle 210 such that the backrest seating supporting member 217 has been brought into contact with the seating support member 216. Thus the plane formed by member 216 and the plane occupied by member 217 have been brought into substantially parallel alignment. Additionally the legs associated with seating portion 200 have been folded by their associated hinge means in a directly inwardly towards seating frame portion 202. The folded configuration illustrated in Figure 9 herein allows the seating structure of the present invention to be compactly stored and conveniently carried.

Figure 10 schematically illustrates, in a perspective view, a second alternative preferred embodiment for configuring a pivotal point of a backrest portion of a collapsible seating structure as configured in accordance with the present invention, the releasable locking mechanism comprising an elongate rigid actuating member having a hinged portion in the form of a swivel joint or a ball joint. Engagement member 207, frame member 203, spring housing 303 and * S S * **S * * S * S S S * * * * * * * *SS * S S* S S S * ** S * * S * S S ** **S S S **S * fork leg portion 302 are substantially the same as those illustrated in Fig.'s 2 to 9 and therefore like elements have kept the same reference numerals. However the releasable locking member of Figure 10 is different to that illustrated in Fig.'s 2 to 9 and is generally indicated at 1001. Releasable locking mechanism 1001 comprises an elongate rod member 1002 that connects with a handle 210 (not shown). On the other side of the bed chair/seating structure a similar configuration is present with a connecting rod 1002 again connecting to handle 210. The releasable locking mechanism 1001 additionally comprises an engagement member 1003 configured to pass through channel 310 and which is attached to fork portion 302 via a threaded nut 1004 that is connected to the end of member 1003. However releasable locking member 1001 differs from releasable locking member 209 of Fig. 2 in that it additionally comprises a hinge portion 1005 such that member 1003 is allowed to rotate (at least in a vertical plane) relative to rod member 1002. Hinge member 1005 may be configured as a swivel joint or a ball joint such that upon a person pulling handle 210 and thereby effecting an upward force on rod member 1002, swivel joint 1005 facilitates movement of engagement member 1003 in an upward direction so as to disengage with the notch in which it is located on annular member 304. In this way disengagement of member 1003 from the tooth and groove configuration of annular member 304 is facilitated by the hinge so that use of the seating structure is made somewhat more user friendly than the embodiment of Fig.'s 2-9.

Figure 11 schematically illustrates, in side elevation view, respective third and fourth alternative preferred embodiments for configuring a pivotal point of a backrest portion of a seating structure as configured in accordance with the present invention, the releasable locking mechanism comprising an elongate rigid actuating member associated with a locking member that may be pushed or pulled depending on the nature of the operating mechanism selected.

In Figure 11 a substantially circular engagement member 1101 (similar to engagement members 206, 207) is illustrated as attached to a seating member support frame 1102 via bolts 1103 and 1104. Bolts 1103 and 1104 have * * * S *S* * S S * S S * S * * * S S * *** S * S* S S S S *S S * S S S S S *S *,* 5 *** 5 threaded ends that thread into suitably arranged orifices located in the body of annular engagement member 1101. Annular engagement member 1101 comprises a plurality of teeth 1105, 1106 separated by grooves or notches such as those indicated at 1107 and 1108. Fork portion 1109 is shown as connected to annular engagement member 1101 via pivotal fixing 1110 which passes substantially perpendicularly through the central point of the planar and substantially circular surface of member 1101. A portion of the backrest frame 1111 affixes to fork portion 1109 via the spring 1112 and spring housing arrangement 1113. The spring/housing arrangement 1112/1113 is configured to effect engagement or disengagement with annular engagement member 1101 via a rotatable L' shaped locking member 1114. Rotatable locking member 1114 is substantially the shape of a "right angle" comprising a first substantially horizontally aligned portion 1115 that is transverse (preferably perpendicular) to a second vertically disposed portion 1116. Member 1114 is configured to rotate about a pivot 1117 located towards the end of portion 1115 that is not connected to portion 1116. Additionally member 1114 is attached to a horizontally disposed plate 1118 that extends beyond the outer regions of the spring housing member 1113. In this way when a force is applied to plate 1118 such as by a downward (push) force (generally indicated by arrow 1119) then plate 1118 is rotated such that the right hand side of the plate (as shown in the Figure) moves upwards resulting in vertical portion 1116 of locking member 1114 being brought into a position such that it disengages with the groove of annular member 1101 in which it was initially housed. Alternatively, a force (pull) generally indicated by upward arrow 1120 may be applied (by an operator pulling on handle 210) such that again member 1116 is brought out of the notch in angular member 1101 that it was housed in. Thus Figure 11 illustrates two possible embodiments such that the device may be configured to work with a push force (see arrow 1119) or a pull force (see arrow 1120) depending upon a given manufacturer's or angler's preferences. A further possibility is to arrange the embodiment of Figure 11 such that instead of member 1114 being pivoted about an end portion of portion 1115, it is pivoted about a point directly at the top of vertically extending portion 1116 (at the connecting junction or corner of portions 1115 and 1116). In this way a lever * . * . a..

* . . . * a * . I a * * * * ... . S *5 S S S S ** S a * . * * I as mechanism may be provided to invoke an upwardly directed force acting at the illustrated circular black point that is shown towards the top of vertical member 1116.

Figure 12 schematically illustrates a back elevation view of a further preferred embodiment of a releasable locking mechanism and framed backrest portion of a collapsible seating structure as configured in accordance with the present invention, the releasable locking mechanism comprising an elongate coupled actuating member in the form of a cable.

The arrangement schematically illustrated in Figure 12 comprises a backrest frame portion 1201 along the length of which runs a first wire cable 1202 at a first side of the frame and a second wire cable 1203 at the opposite side of the frame. Cable 1202 connects a locking member located at a first pivot portion 1204 at the end of one of the ends of frame portion 1201 to a lever mechanism 1205. Similarly cable 1203 connects a locking member located at a pivot portion 1206 to lever mechanism 1205. Wire cables 1202 and 1203 may suitably comprises cables of the type used in the art of cycle breaks and cycle gear systems. Similarly lever mechanism 1205 may take the form of a cycle type of break lever. The wire cables 1202, 1203 are held in position along frame portion 1202 so as to ensure that a required tensional force can be applied by lever 1205 along the length of each cable and thereby raise the locking members associated with pivotal portions 1204 and 1206. In accordance with this wire cable embodiment various forms of locking arrangement may be employed so as to provide incremental adjustment of the backrest portion relative to the seating portion. In the embodiment shown the locking arrangement is provided by a pin assembly (not shown) configured to locate within a series of holes such as holes 1207 and 1208 located on pivot portion 1204.

Figure 13 schematically illustrates a cross-sectional perspective view of the region of the pivot point of Figure 12 so as to further detail certain hidden components of the releasable locking mechanism.

* * * * SSS * * * * * * * * 0 * * S S * *** S S S* S S S S Se S * * S S * S IS SS* S 5 eeS I In Figure 13 the releasable locking mechanism illustrated in Figure 12 is illustrated such that pivot portion 1204 is connected to a seating portion frame 1301. Wire cable 1202 is affixed at the pivot portion end to an elongate pin 1302 that is configured to locate in holes such as those indicated at 1207 and 1208 of the substantially circular engagement member 1303 associated with pivot point 1204. Thus a tensile force applied to cable 1202 (generally indicated by substantially vertical arrow 1304 effects a force upon pin 1302 such that pin 1302 is removed from the hole accommodating it. The upward force 1304 may be generated via an operator of the seating structure pressing lever 1204. Similarly if the operator of the device releases lever 1205 then pin 1302 will be allowed to engage with the surface of engagement member 1303 until it locates in one of the plurality of holes 1207, 1208.

Figure 14 schematically illustrates a back elevation view of a further preferred embodiment of a releasable locking mechanism and framed backrest portion of a seating structure as configured in accordance with the present invention, the releasable locking mechanism comprising an electrically operated actuating member.

Substantially the same components are included in Figure 14 as those described in relation to Figure 12 and like numbering has been adopted.

However in place of lever mechanism 1205 an electrically operated assembly 1401 is provided to effect a tensile force upon cables 1202 and 1203. Electrically operated assembly 1401 may comprise re-chargeable batteries and a motor such that the motor is configured to turn a cog arrangement that is attached to cables 1202 and 1203. In this way a force may be applied upon cables 1202 and 1203 or released therefrom so as to effect engagement of a pin into holes associated with pivotal portions 1204, 1206 or so as to withdraw said pin from said holes.

In accordance with the various preferred embodiments of the present invention as illustrated schematically in Figures 2 to 14 the angle of inclination * * S S 555 * S S S S S S * S * a S S S *S* * S *S S a * S *a S * a * S * S SI SSI S S **S I between the seating portion and the backrest portion may thus be directly increased and decreased from substantially any angle of inclination that the seating structure is currently positioned in. The pivotal portions, such as those indicated at 204, 205 in Figures 2 to 9 and those of the further preferred embodiments in Figures 10 to 14 are, in accordance with the present invention, arranged as a pair such that a pivotal portion is provided at each side of the seating structure. In this way the releasable locking mechanism is configured such that it provides a coupling means that it is configured to mechanically couple activation of the engagement or disengagement of a locking member with an engagement member located on each side of the seating structure. The coupling means thereby provides the operator with the means to substantially simultaneously effect engagement or disengagement of the locking mechanisms associated with each pivotal portion.

Although the locking mechanism in the preferred embodiments illustrated in Figures 2 to 14 has generally been indicated as being associated with the backrest portion of a seating structure, those skilled in the art will realise that the releasable locking mechanism can alternatively be configured such that it is associated with the seating portion. However in the best mode contemplated a seating structure according to the invention is most suitably configured such that the releasable locking mechanism is substantially arranged in a plane parallel to that of the backrest portion. Furthermore a releasable locking mechanism as configured in accordance with the present invention is preferably configured for operation on the rear side of the backrest portion.

In the context of the description of the various preferred embodiments of the present invention the relative orientations of particular components are referenced to the horizontal and the vertical by which it is herein assumed that the seating structure is located on substantially horizontal ground or on another horizontal structure such as a pier associated with a body of water. The collapsible seating structure, when in use will be positioned such that the seating portion 200 lies in a substantially horizontal plane. In the angular configuration * S * S 555 * S S S S S * S S * * S S S *S5 S S S5 a S S * *5 S * S * * * S S* SSS S * S.. * depicted in Figure 2 the backrest portion thus lies in a substantially vertical plane and for the sake of convenience component orientations in Figures 2-7 and 10-14 have been referred to whilst the seating structure is assumed to be on substantially horizontal ground with the backrest and seating portions oriented as indicated in Figure 2.

According to further specific implementations of the present invention engaging members 206, 207 may be affixed to the respective ends of releasable locking mechanism 209 such that a projection extending from frame 202 is configured to interface with notches 306 of annular engagement member 304. In such an embodiment, each engaging member 205, 206 would be moveable in the direction of arrow 600, with reference to Figure 6 herein and biased by the spring mechanism 700 of Figure 7 herein.

The aforementioned preferred embodiments of the invention have been described in relation to a coupling means configured to mechanically couple activation of engagement or disengagement of a first locking member with a first engagement member and a second locking member with a second engagement member such that said activation is thereby effected substantially simultaneously.

However those skilled in the art will understand that the pivot mechanisms may be configured to operate independently of each other without any such coupling being required. Thus, for example, the toothed drum embodiments of a pivot mechanism described in relation to Figs. 2-11 and the hole and pin embodiments of a pivot mechanism described in relation to Figs. 12-14 may be operable individually without a coupling being present between a pair of such pivot mechanisms. Thus a further preferred embodiment of the present invention concerns a releasable pivot assembly that is substantially similar to that described in relation to Fig. 3, but without a coupled releasable locking mechanism 209. In this latter embodiment mechanism 209 is thus replaced with a non-coupled handle means to effect movement of the means to engage 308.

Suitably such a non-coupled handle may comprise a knob or ball like structure to facilitate engagement/disengagement as required. Furthermore the end * * * * *** * * S S S S S S S * * S a S *SS S S S. * * S * 55 5 * S S S S * S* 55. S S*S S comprising the securing bolt 309 may be configured to operate in conjunction with a spring catch located on the inside of the frame to further facilitate the action of engaging or disengaging the means to engage 308.

Those skilled in the art will also appreciate that various aspects of the present invention may be used in connection with a wide variety of seating structures other than collapsible and/or portable seating structures. Thus, in particular, the various aforementioned embodiments of releasable locking mechanisms as configured in accordance with the present invention may find application on many kinds of seating structures besides collapsible and/or portable seating structures.

In addition to the seating structures used in the art of angling the present invention may also find application in the leisure activities of camping and caravan touring.

* S. .1S * S S S * S * S * * S * * S SSS S * S. S * S S 55 S * * * S S * at SS* S S.. S

Claims

Claims: 1. A collapsible seating structure for use by a person, said

seating structure comprising a frame of rigid elongate material, said frame comprising a seating portion attached at first and second pivotal points to a backrest portion, said first and second pivotal points each comprising an engagement member configured to engage with or disengage from respective first and second locking members of a releasable locking mechanism to thereby enable the angle of inclination between said seating portion and said backrest portion to be directly increased and decreased from substantially any angle of inclination, said seating structure characterized in that said releasable locking mechanism additionally comprises: coupling means configured to mechanically couple activation of said engagement or said disengagement of said first locking member with said first engagement member and said second locking member with said second engagement member such that said activation is thereby effected substantially simultaneously; and handle means connected to said coupling means and located on one of said portions, said handle means functioning to enable said person to use a hand to effect said activation of said coupling means whilst simultaneously functioning to enable said person to use said same hand to adjust said angle of inclination.
2. A seating structure as claimed in claim I wherein each said engagement member is mechanically coupled to the other to enable said engagement and said disengagement to be performed substantially by an operator using said releasable locking mechanism to apply a single force from the set comprising a tensile force and a compressional force.
3. A seating structure as claimed in any of claims I or 2 wherein each said engagement member is mechanically coupled to the other by virtue of said * a a Ia.

* S S S a * * S I a p * * *s. I S. - S S S 55 * * . I I S - .5 *5* * I 1,1 - releasable locking mechanism to enable said engagement and said disengagement to be performed substantially from a single location on said structure.
4. A seating structure as claimed in any of claims I to 3 wherein each said engagement member is configured with means to enable said angle of inclination to be incrementally adjusted.
5. The seating structure as claimed in any of claims I to 4 wherein a said engagement member comprises a plurality of teeth that are engageable by said respective locking member.
6. The seating structure as claimed in any of claims I to 5 further comprising bias means configured to bias a said locking member in locking engagement with a said engagement member.
7. The seating structure as claimed in any preceding claim wherein a said engagement member is formed as a wheel-like member, said teeth formed by concave curved regions spaced apart relative to one another at a circumference of said wheel-like member.
8. The seating structure as claimed in claims 6 or 7 wherein said bias means comprises a helical spring provided in contact with a portion of said backrest portion and said associated locking member.
9. The seating structure as claimed in claim 8 wherein said spring is housed within a spring housing connected to said frame of said backrest portion.
10. The seating structure as claimed in any preceding claim wherein said releasable locking mechanism comprises an elongate member extending between said first and second pivotal points, said releasable locking mechanism substantially being "U"-shaped. a a

* S S S - S a - S S S S p I * S S as s a * . S hi spa a
11. The seating structure as claimed in any preceding claim wherein a region of said releasable locking member is remotely positioned relative to said first and second pivotal points the remotely positioned region being configured as a handle/lever to effect operation of said locking mechanism.
12. The seating structure as claimed in any preceding claim wherein said releasable locking mechanism comprises a rigid elongate material in the form of a rod.
13. The seating structure as claimed in any of claims I to 11 wherein said releasable locking mechanism comprises an elongate wire.
14. The seating structure as claimed in any preceding claim wherein a said locking member comprises an end region of said releasable locking mechanism, said end region being elongate and oriented at substantially 90 to the portion of said releasable locking mechanism to which it is connected.
15. The seating structure as claimed in any preceding claim wherein a said locking member of said releasable locking mechanism comprises a hinge attachment as regards its attachment to the remainder of said releasable locking mechanism.
16. The seating structure as claimed in any preceding claim wherein a said engagement member is connected to said frame of said backrest portion by a fork comprising a groove portion through which a said locking member passes through, said locking member capable of sliding back and forth within said groove portion to contact said engagement member.
17. The seating structure as claimed in any preceding claim wherein said releasable locking member comprises an elongate structure aligned in a substantially planar arrangement and positioned such that the plane of said S * S S * S I I I * I I I III I I I S * S 55 S S $ S S I S S 5s5 5 $ . locking mechanism is substantially parallel to the plane defined by said backrest portion.
18. The seating structure as claimed in claim 11 wherein said handle means of said locking mechanism is positioned towards one end of said frame of said backrest portion and a said locking member to engage with a said engagement member is positioned towards a second end of said frame of said backrest portion.
19. The seating structure as claimed in any preceding claim wherein said locking mechanism is substantially located on the rear side of said backrest portion.
20. The seating structure as claimed in claim I wherein said releasable locking mechanism comprises an electrically powered motor.
21. The seating structure as claimed in any preceding claim wherein said structure is comprises at least one collapsible leg assembly.
22. A collapsible seating structure as hereinbefore described with reference to any one of the accompanying drawings. ( ((

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22. The seating structure as claimed in any preceding claim wherein said seating structure comprises an angler's seat.

23. The seating structure as claimed in any of claims I to 21 wherein said seating structure comprises an angler's bed chair.

24. A collapsible framed seating structure comprising first and second pivot assemblies, said seating structure comprising a coupled releasable locking mechanism.

25. A collapsible framed seating structure pivot assembly comprising: a locking member in the form of an elongate rod; and an engagement means * * S * * * * * S..

: : .* S.. * * : * *e * * : :.

configured to receive and thereby engage with said locking member, wherein said engagement means is provided with a plurality of engagement locations.

26. A collapsible seating structure as hereinbefore described with reference to any one of the accompanying drawings.

27. A collapsible framed seating structure pivot assembly as hereinbefore described with reference to any one of the accompanying drawings.

S

* * * S S I S * ** *. : : ** * : *, 5_. * * S: :. 32.

Amendments to the claims have been filed as follows 1. A collapsible seating structure for use by a person, said seating structure comprising a frame of rigid elongate material, said frame comprising a seating portion attached at first and second pivotal points to a backrest portion, said first and second pivotal points each comprising an engagement member configured to engage with or disengage from respective first and second locking members of a releasable locking mechanism to thereby enable the angle of inclination between said seating portion and said backrest portion to be directly increased and decreased io from substantially any angle of inclination, said releasable locking mechanism additionally comprising: coupling means configured to mechanically couple activation of said engagement or said disengagement of said first locking member with said first engagement member and said second locking member with said second engagement member such that said activation is thereby effected substantially simultaneously; and handle means connected to said coupling means and located on one of said portions, said handle means functioning to enable said person to use a hand to effect said activation of said coupling means whilst simultaneously functioning to enable said person to use said same hand to adjust said angle of inclination, wherein said releasable locking mechanism is configured to allow the backrest portion to be rotated about said pivotal points such that said backrest portion is folded over into a plane substantially parallel to and adjacent to that of the seating portion.

2. A seating structure as claimed in claim 1 wherein each said engagement member is mechanically coupled to the other to enable said engagement and said disengagement to be performed substantially by an operator using said releasable locking mechanism to apply a single force from the set comprising a tensile force and a compressional force.

3. A seating structure as claimed in any of claims I or 2 wherein each said engagement member is mechanically coupled to the other by virtue of said releasable locking mechanism to enable said engagement and said disengagement to be performed substantially from a single location on said structure.

4. A seating structure as claimed in any of claims I to 3 wherein each said engagement member is configured with means to enable said io angle of inclination to be incrementally adjusted. ( (.

5. The seating structure as claimed in any of claims I to 4 wherein a said engagement member comprises a plurality of teeth that are engageable by said respective locking member.

6. The seating structure as claimed in any of claims I to 5 further comprising bias means configured to bias a said locking member in locking engagement with a said engagement member.

7. The seating structure as claimed in any preceding claim wherein a said engagement member is formed as a wheel-like member, said teeth formed by concave curved regions spaced apart relative to one another at a circumference of said wheel-like member.

8. The seating structure as claimed in claims 6 or 7 wherein said bias means comprises a helical spring provided in contact with a portion of said backrest portion and said associated locking member.

9. The seating structure as claimed in claim 8 wherein said spring is housed within a spring housing connected to said frame of said backrest portion.

10. The seating structure as claimed in any preceding claim wherein said releasable locking mechanism comprises an elongate member extending between said first and second pivotal points, said releasable locking mechanism substantially being "U"-shaped.

II. The seating structure as claimed in any preceding claim wherein a region of said releasable locking member is remotely positioned io relative to said first and second pivotal points the remotely positioned region being configured as a handle/lever to effect operation of said locking mechanism.

12. The seating structure as claimed in any preceding claim wherein said releasable locking mechanism comprises a rigid elongate material in the form of a rod.

13. The seating structure as claimed in any of claims I to 11 wherein said releasable locking mechanism comprises an elongate wire.

14. The seating structure as claimed in any preceding claim wherein a said locking member comprises an end region of said releasable locking mechanism, said end region being elongate and oriented at substantially 90 to the portion of said releasable locking mechanism to which it is connected.

15. The seating structure as claimed in any preceding claim wherein a said locking member of said releasable locking mechanism comprises a hinge attachment as regards its attachment to the remainder of said releasable locking mechanism.

16. The seating structure as claimed in any preceding claim wherein a said engagement member is connected to said frame of said backrest portion by a fork comprising a groove portion through which a said locking member passes through, said locking member capable of sliding back and forth within said groove portion to contact said engagement member.

17. The seating structure as claimed in any preceding claim wherein said releasable locking member comprises an elongate structure aligned in a substantially planar arrangement and positioned such that the plane of said locking mechanism is substantially parallel to the plane defined by said backrest portion.

18. The seating structure as claimed in claim 11 wherein said handle means of said locking mechanism is positioned towards one end of said frame of said backrest portion and a said locking member to engage with a said engagement member is positioned towards a second end of said frame of said backrest portion.

19. The seating structure as claimed in any preceding claim wherein said locking mechanism is substantially located on the rear side of said backrest portion.

20. The seating structure as claimed in claim I wherein said releasable locking mechanism comprises an electrically powered motor.

21. The seating structure as claimed in any preceding claim wherein said structure is comprises at least one collapsible leg assembly.