BACKGROUND ART Collapsible chairs have been used for recreational purposes for many years and have become popular for their portability and ease of storage. There have been many varieties of collapsible chairs from the very early folding lawn chairs to more stylish modern designs.

Although these chairs are generally very convenient, they must necessarily utilize a rigid framework which is capable of withstanding the wear-and-tear of being collapsed and reassembled, and must still provide a solid structural support for the weight of a user.

Consequently, the framework, once assembled, is generally unyielding and does not easily conform to the anatomy of an individual user. Even those models using fabric portions which are stretched between the frame elements have limited flexibility, and provide only small variation in comfort positions.

Therefore, there is a need for collapsible furniture which has resilient rear frame portions which can more easily provide proper support and which more easily adapt to a variety of users.

DISCLOSURE OF INVENTION Accordingly, it is an object of the present invention to provide a chair which is collapsible to a compact configuration.

Another object of the invention is to provide a collapsible chair which has resilient back-support elements.

And another object of the invention is to provide a collapsible chair which is adaptable to the body shapes and weights of a variety of users.

Briefly, one preferred embodiment of the present invention is a collapsible chair, having a frame assembly including a number of angled frame members. The upper ends of

the angled frame members are pivotally attached to upper connectors, and the lower ends are pivotally attached to feet. The frame assembly as a whole is configured to expand outwardly from a central area. The frame assembly further includes back support uprights and rear corner upright members. Each of the rear corner upright members has an upper end which is pivotally connected to one of said back support uprights at a flexible joint. The chair also includes a support surface, having a back portion which is held in position by the back support uprights. The flexible joint includes a resilient support assembly which biases the back portion to an upright position. This resilient support assembly includes a biasing mechanisms such as a leaf-spring which is preferably held in position by pins.

An advantage of the present invention is that it includes a resilient rear frame portion which adapts to the users weight and body shape.

Another advantage of the present invention is that it is collapsible to a very compact configuration.

A further advantage of the present invention is that the frame members preferably are pivotally linked, so that the whole frame collapses towards a center point, and when one corner is moved towards the center, the other corners act in unison to also collapse inwards.

These and other objects and advantages of the present invention will become clear to those skilled in the art in view of the description of the best presently known mode of carrying out the invention and the industrial applicability of the preferred embodiment as described herein and as illustrated in the several figures of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The purposes and advantages of the present invention will be apparent from the following detailed description in conjunction with the appended drawings in which: FIG. lA shows a front isometric view of the collapsible chair with resilient joint in an expanded configuration; FIG. 1 B shows a detail view of the detail circle A shown in Fig. 1 A ; FIGS. 2A-C illustrate details of the resilient joint as it is flexed; FIGS. 3A-C shows details of the resilient joint as it is flexed; FIGS. 4A-D and 5A-D also show details of the resilient joint as it is flexed; FIG. 6 illustrates a front isometric view of the frame of the collapsible chair, showing

the direction in which the frame members collapse; FIG. 7 shows the frame in collapsed configuration; FIG. 8 shows the rear foot assembly shown within detail circle A of Fig. 6; FIG. 9 shows the rear upper pivot assembly, shown within detail circle B of Fig. 6; and FIG. 10 shows the front upper pivot assembly, shown within detail circle C of Fig. 6.

BEST MODE FOR CARRYING OUT THE INVENTION FIGS. 1A and B illustrate the collapsible chair with resilient internal back frame members 10, with the chair 10 in expanded configuration 2. It generally includes a frame assembly 12 and a fabric covering 14. The frame assembly 12 includes a lower framework 16 having four feet 20, which include pivot assemblies 22, and a number of frame members 24 having pivots 26 located at or near the midpoints of the members 24. Arm supports 28 are formed from the upper ends of two of the frame members 24. Rear upright members 32 are attached at the rear feet 20, and extend in a generally vertical direction until they are pivotally attached to a pair of back support uprights 34. The fabric covering 14 includes a seat portion 36, a back portion 38 and arms 40, all of which are stretched or extend between various frame members.

FIG. 1B is a detail of a section of the chair shown in detail circle A of Fig. 1A. The rear upright member 32 shown is connected to a back support upright 34 by a flexible joint 31, having an internal spring member 35, which preferably acts as a resilient hinge member in the manner of a leaf spring 33 to make a resilient joint 37. The back portion 38 is thus allowed to deform in response to the weight of the user, but the action of the spring member 35 biases the back portion to return to an upright position. The back portion 38 thus is able to adjust to differences in users'body sizes and shapes.

FIGS. 2A-C and 3A-C illustrate details of the rear upright member 32, back support member 34 and internal spring member 35 as the resilient joint 37 is flexed. The spring member 35 is preferably made of a strong resilient material with a high spring rate, such as spring steel, and is preferably made into a thin strip which can fit within the hollow tubing of the rear upright member 32 and back support member 34 in the manner of a leaf-spring 33.

FIGS. 4A-D and 5A-D also show details of the rear upright member 32, back support member 34 and internal spring member 35 as the spring member 35 is flexed. Figs. 4A and 5A show front plan views of the resilient joint 37. Figs. 4B and 5B show cross-sectional views as taken though sections B-B in Figs. 4A and 5A. Figs. 4C and 5C show side plan views of the resilient joint 37 in an undeflected position. Figs. 4D and 5D show side plan views of the resilient joint 37 as it deflects to its maximum. It will be noticed that the spring member 35 in Figs. 4A-D is narrower in width than that in Figs. 5A-D, and the maximum deflection is greater. The wider spring member 39 is also positioned between a rear upright member 32 and a back support member 34 which have a slightly greater separation 43. The spring rate of the wider spring member 39 may be expected to be slightly higher than that of the narrower spring member 41, and variations in biasing force may also be accomplished by using different thicknesses as well as varying the separation 43.

Pins 45 are also shown attaching the spring members 39,41 to the rear upright member 32, and back support member 34. This is but one way of attaching the spring members 35, and many other variations of fasteners may be used, including welding, bolts, etc.

FIG. 6 shows an isometric view of the frame 12, and arrows 6 showing the direction of movement of the feet 20, as they collapse toward a common center point 8. Due to the pivotally linked nature of the frame members 24, the whole frame 12 collapses towards the center point 8, and when one foot 20 is moved towards the center 8, the other feet 20 act in unison to also collapse inwards. The rear foot pivot assembly 42 is shown within detail circle A, and is shown in more detail in Fig. 8 below. Likewise, the upper rear pivot assembly 44 is shown within detail circle B, and Fig. 9 below, and upper front pivot assembly 46 is within detail circle C, and Fig. 10 below.

FIG. 7 shows the frame 12 in collapsed configuration 4.

FIG. 8 shows the rear foot pivot assembly 42, shown within detail circle A of Fig. 6.

Members 24 (shown in dashed line) are pivotally attached to foot 20 by pivots 26, and a rear upright member 32 is inserted into a socket 48.

FIG. 9 shows the rear upper pivot assembly 44, shown within detail circle B of Fig. 6.

Members 24 (again shown in dashed line) are attached by pivots 26, and rear upright

member 32 passes through a through-hole 50, becoming back support upright 34.

FIG. 10 shows the front upper pivot assembly 46, shown within detail circle C of Fig.

6. Members 24 are attached by pivots 26, and the member 24which becomes an arm 28 passes though a slot 52.

Although the chair shown and discussed above has arms included, the resilient back support elements of the present invention can also be used on a chair without arms, as well as on a couch or loveseat, and will provide the same advantages.

In reference to the chair frame assembly 12, as a whole, seen particularly in Fig. 6, the pivot assemblies 22,20,44,46 and pivots 26 connect all the angled members 24 to each other, so there are no loose pieces to be gathered and assembled. The frame 12 can be thought of as an extended scissors-frame assembly 54 since the tops and bottoms of each pair of frame members scissor together or apart. These scissor pairs 56 are then joined in an extended scissor assembly 54 where the ends of multiple pairs are joined at the pivot assemblies 22. They also allow the frame assembly 12 as a whole to be collapsed or expanded in a very easy and efficient manner. Force directed at any one of the corners causes movement in all the other corners, so that there is movement of the whole frame assembly 12 in either an inward or outward direction, relative to the central area 8. The pivots 26 allow the frame assembly 12 to move towards a central area 8 from all sides as a unit when the frame 12 is to be collapsed, and to move away from this central area 8 when expanding.

This configuration will be spoken of as"expanding outwardly from a central area", although it is to be understood that one of the feet may actually remain in fixed position, while the remainder of the feet move outward. In other words, the central reference area from which the feet move, may itself move laterally. One example of this occurs when the collapsed support frame is placed in the corner of a yard, where, say, the left rear foot of the frame is in the left rear corner of the yard, and thus is constrained from movement in a further leftward or rearward direction. When the frame expands, all the other, non-constrained feet will expand outwardly from a central area to the right, or forward, or both, even as the central area itself will move to the right and forward, relative to the immobile left rear foot.

It should also be understood that all the lines of direction of the movement of the feet are not expected to intersect at a precise point. The central area 8 is thus a relatively small region from which the feet 20 move outwardly, but there should be no inference that all feet must move in a specific lines, such as radially from a single specific center point. To one

skilled in the art, it will be apparent that if such precise directionality were attempted, manufacturing errors would inevitably introduce variations. Thus, the expansion is considered to move outwardly from a central area or region, and should not be construed to imply any particular lines of direction, other than generally outward from this central area.

The direction arrows and central area 8 shown in Fig. 6 are therefore not provided to show specific lines of movement which must be followed, but merely a general direction of movement towards, or away from, a general central area 8.

Also, though the resilient internal frame members are preferably used on a collapsible chair which expands from a central area, as described above, the resilient internal members are also useable on other types of chairs, including those which may not collapse at all.

While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Many other uses and variations will be obvious to one skilled in the art.

INDUSTRIAL APPLICABILITY The present collapsible chair with resilient support elements 10 is well suited for application in the home, backyard, or on camping trips and picnics.

The collapsible chair with resilient support elements 10,50 has a frame assembly 12 which includes angled frame members 24, the upper ends of the angled frame members 24 being pivotally attached to upper pivot assemblies 44,46, and the lower ends being pivotally attached to feet 20. The frame assembly 12 also includes upright members 32 and as a whole expands outwardly from a central area 8. A back support framework 18 includes a pair of back support uprights 34. Where the rear corner uprights 32 and the back support uprights 34 meet, they are joined by resilient support assemblies 30, to form a flexible joint 31. The resilient support assembly 30 may include a number of resilient internal spring members 35 including leaf-springs 33.

When the chair 10 is to be used, it is set up so that it rests on its feet 20. Force is then directed at any one of the corners, causing movement in all the other corners, so that there is movement of the whole frame assembly 12 in either an inward or outward direction, relative to the central area 8. The pivots 26 allow the frame assembly 16 to move towards a central area 8 from all sides as a unit when the frame 12 is to be collapsed, and to move away from this central area 8 when expanding. Thus in one swift motion, the chair 10 is expanded and ready to use.

The resilient support assemblies 30 allow the back panel 38 to flex somewhat in response to the weight and bodily configuration of a user. By allowing the back to deform slightly, while still maintaining good back support, the chair 10 is more adaptable to a larger range of body sizes and types than a conventional chair. The chair 10 preferably has separate back support uprights 34 for more independent movement of each back support upright 34 in response to weight distribution, and thus is very adaptable to variations in body shape and contour.

The present collapsible chair with resilient support elements 10 can be set up very quickly, has no loose parts to keep track of, and is uniquely adaptable to a great variety of shapes and sizes of users. It has many uses in the home, backyard, or on camping trips and picnics.

For the above, and other, reasons, it is expected that the collapsible chair with resilient support elements 10 of the present invention will have widespread industrial applicability.

Therefore, it is expected that the commercial utility of the present invention will be extensive and long lasting.