Folding chair

[0002] The present invention relates to a folding chair, and more specifically to a portable folding chair designed to fold in two directions for easier transport and compact storage.

[0003] Folding chairs can be found in a wide variety of outdoor recreational settings. From beach resorts to suburban backyards, people enjoy the portability and ease of storage of these chairs.

[0004] Known to the art are chairs that fold in two directions, often referred to as a quad chair, i.e., the seat folds in towards the backrests and the sides fold in towards each other. However, prior art chairs that fold in two directions achieve their compactness by eliminating rungs from the backrest and seat frames, with the primary support for a user being provided by the upholstery. This decreases the level of seat and back support, sacrificing comfort and stability.

[0005] Also known to the art are folding chairs that employ longer rear legs which extend rearward past the backrest. This design provides greater stability to the unfolded chair. However, prior art folding mechanisms fold the seat upward and push the rear leg downwards in the opposite direction. The result is a taller, less compact package when the chair is folded.

[0006] Thus there exists a need in the art for a chair that folds in two directions into a compact package that also provides enhanced seat and back support. There is also a need in the art for a chair that provides the stability offered by a rear leg that extends past the back of the chair and that also folds into a shorter package.

[0007] A folding chair, according to an exemplary embodiment of the present invention, makes use of collapsible rungs in a backrest and seat, permitting the chair to fold compactly in two directions while providing better back and seat support than is found in the prior art. The stability of the present invention is further enhanced by the chair's upholstery which, when mounted, further forces the top rung of the chair downward and the center rung rearward, making the chair very rigid in the open position, especially when being used. Moreover, the siderails and back supports slide freely along the chair's rear legs, creating a folding mechanism that folds the seat upward while also pulling the rear leg upward in the same direction. Thus the rear legs extend past the back of the chair for greater stability in the unfolded state without increasing the height of the chair in its folded state, resulting in a very compact package.

[0008] FIG. 1 illustrates a front view of a folding chair in its unfolded state according to an exemplary embodiment of the present invention.

[0009] FIG. 2 illustrates a side view of a folding chair in its unfolded state according to an exemplary embodiment of the present invention.

[0010] FIG. 3 illustrates a close up view of a releasably lockable hinge joint according to an exemplary embodiment of the present invention.

[0011] FIG. 4 illustrates a folding chair with upholstery attached according to an exemplary embodiment of the present invention.

[0012] FIG. 5 illustrates a folding chair in its folded state according to an exemplary embodiment of the present invention.

[0013] FIG. 6 illustrates a tendon joint according to an exemplary embodiment of the present invention.

[0014] FIG. 7 illustrates a lap joint according to an exemplary embodiment of the present invention.

[0015] Various aspects of the present invention will be described, and for purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without these specific details. Furthermore, well known features have been omitted or simplified in order to prevent obscuring the present invention.

[0016] According to an exemplary embodiment of the present invention, FIGS. 1 and 2 depict a folding chair 100 in its unfolded state. Top rung 130 and center rung 170 are each made up of, for example, three separate segments 130a-cand 170a-c, respectively, pivotally connected to one another with releasably lockable hinge joints 300. A releasably lockable hinge joint 300 may be a tendon joint, depicted in FIG. 6, or a lap joint, depicted in FIG. 7, or any standard or suitable joint known to the art that functions as a releasably lockable hinge joint 300, indicated for example in the dotted box. Referring to FIGS. 6 and 7, a lap joint differs from a tendon joint in the type of hinge used. The hinge on a lap joint has, for example, two fingers 710aand 720athat are pivotally interconnected. The hinge on a tendon joint has, for example, four fingers 610a-band 620a-bwhich pivotally interconnect by overlapping each other such that, for example, finger 610bfits between fingers 620aand 620b, and finger 620bfits between fingers 610aand 610b.

[0017] Each end of rung segments 130a-cand 170a-c, which may be composed of, for example, injection molded plastic or cast aluminum, are, for example, pivotally connected with releasably lockable hinge joints 300. End segments 130aand 130cand 170aand 170care also pivotally connected by way of releasably lockable hinge joints 300 to tube caps 120, which may be composed of, for example, injection molded plastic or cast aluminum. An exemplary releasably lockable hinge joint is depicted in FIG. 3. Segments 130a-cand 170a-care preferably curved as shown in FIG. 1, but may also be straight.

[0018] FIGS. 3, 6, and 7 depict respectively closer views of a releasably lockable hinge joint 300, a tendon joint 600, and a lap joint 700 according to an exemplary embodiment of the present invention. Segment 310, 610, 710 which may be a tube cap 120 or another rung segment (e.g., 130b-cor 170b-c) , moves with respect to segment 320, 620, 720 which may also be a tube cap 120 or another rung segment (e.g., 130a-bor 170a-b), about an axis of rotation 330, 630, 730. Rotation of segment 310, 610, 710 with respect to segment 320, 620, 720 is stopped, for example, when segment 310, 610, 710 comes into contact with position block 340, 640, 740, which is, for example, a surface of a slot or notch cut into the ends of segments 310, 320, 610, 620, 710, 720 at the portion where each of the segments interconnect. For example, the slot or notch is shaped to limit the range of rotation to only one direction and to halt the rotation when a segment 310, 320, 610, 620, 710, 720 comes into contact with a side of the slotted or notched portion which serves as a position block 340, 640, 740. Thus position block 340, 640, 740 of releasably lockable hinge joint 300, 600, 700 limits the range of rotation of each of the segments 310, 320, 610, 620, 710, 720 of top rung 130 or center rung 170 with respect to one another, halting the rotation at a predetermined critical angle. The critical angle is set, for example, as a function of the dimensions of position block 340, 640, 740. Different critical angles may be employed to modify the shape of top rung 130 and center rung 170, for example, to make the rungs 130 and 170 more curved, less curved, or straight, thus varying the overall width of the chair 100.

[0019] When chair 100 is in its unfolded state, for example as shown in FIG. 1, an upward force applied to top rung 130, such as by a person pulling upward on center rung segment 130bof the rung 130, causes the rung segments 130a-cof top rung 130 to pivot or rotate with respect to one another. As a result, rung segments 130aand 130cwill depend downwards from center rung segment 130b. Similarly, a user pulling upward or forward on center rung segment 170bwould cause rung segments 170aand 170cto depend downward from rung segment 170b.

[0020] By contrast, when a downward force is applied to top rung 130 or a rearward force is applied to rung 170, the movement of the rung segments 130a-cor 170a-cis stopped by the action of position blocks 340 of releasably lockable hinge joint 300.

[0021] Thus, for example, in the unfolded state, top rung 130 will remain rigid in response to a force applied to the rung in a downward direction, and will bend in response to a force applied in the upward direction. Similarly, center rung 170 will remain rigid in response to a force applied to rung 170 in a rearward direction, but will collapse in response to a force applied in the forward direction. According to an embodiment of the present invention, movement of rungs 130 and 170 in the upward direction to fold the chair cause movement of the seat portion toward the back portion as well as movement of the arm portions of the chair towards each other.

[0022] A backrest according to an exemplary embodiment of the present invention is made up of, for example, two back supports 140, which may be composed of, for example, aluminum tubing. The top ends of back supports 140 are, for example, rigidly connected to a tube cap 120 which is in turn pivotally connected to the ends of a top rung 130 by way of a releasably lockable hinge joint 300. A seat frame is made up of, for example, two side rails 230, which may be composed of, for example, aluminum tubing. The forward ends of side rails 230 are rigidly connected to tube caps 120 which are in turn pivotally connected to the ends of a center rung 170 (e.g. 170a, 170c) by way of a releasably lockable hinge joint 300.

[0023] Referring to FIGS. 1 and 2, bottom ends of back supports 140 and rear ends of side rails 230 are, for example, each pivotally connected to a slide pivot 190. A slide pivot 190, which may be composed of, for example, injection molded plastic or cast aluminum, is disposed around each rear leg 220 such that rear legs 220 pass through slide pivots 190. Similarly, a pivot 180, which may be composed of, for example, injection molded plastic or cast aluminum, disposed around each rear leg 220, such that rear legs 220 also may pass through pivots 180.

[0024] As can be seen from FIG. 1, each pivot 180 is, for example, pivotally connected to one end of a crossrail 110, which may be composed of, for example, aluminum tubing, and slides freely along a respective upper portion of rear leg 220. Pivotally connected to the other end of each crossrail 110 is the bottom portion of a slide pivot 190. Slide pivot 190 slides freely along the lower portion of rear legs 220. Crossrails 110 also may be pivotally connected to one another at their approximate centers. Thus, pivots 180, slide pivots 190 and crossrails 110 form a scissors-like structure that opens and closes by sliding along the rear legs 220 of chair 100. It will be apparent to one skilled in the art, that this scissors-like structure, which slides along rear legs 220, provides support by which chair 100 maintains its unfolded state, and provides the mechanism by which the sides of chair 100 fold inwards.

[0025] Front legs 210 and rear legs 220 may be composed of, for example, aluminum tubing. The top ends of rear legs 220 and the top ends of front legs 210 are, for example, pivotally connected to a forward portion of arm rests 150 such that each front leg 210 shares a common vertex and a common pivoting connector with a rear leg 220. The rear portion of arm rests 150 are pivotally connected, for example, to the center portion of back supports 140. Front legs 210 are pivotally connected, for example, to side rails 230 at the approximate front portion of side rails 230.

[0026] Referring to FIG. 4, according to an exemplary embodiment of the present invention, upholstery 410, which may be composed of, for example, nylon or polyester, is fastened to top rung 130, for example, at 415 and 420, and is also fastened to center rung 170 at 425 and 430. FIG. 4 also depicts use of gripping elements 131, 171 for gripping the center rungs 130b, 170b. Upholstery 410 is further connected to back supports 140, for example using loops at 435, 440, 445, and 450, and to side rails 230 using loops at 455 and 460. Other conventional fastening means to connect the upholstery to the frame may be used. The weight of a person sitting in chair 100 further applies a downward tension to upper rung 130 at loops 415 and 420, while simultaneously applying a rearward tension to center rung 170 at loops 425 and 430. These tension forces add to the stability of chair 100, making the chair 100 very rigid in the operi position when being used.

[0027] As illustrated in FIG. 5, according to an exemplary embodiment of the present invention, folding chair 100 folds in one direction by lifting center rung 170 up towards top rung 130 until side rails 230 are substantially parallel and closely spaced to back supports 140. This folding action raises arm rests 150 to a position substantially parallel to and closely spaced to side rails 230 and back supports 140, while pulling rear legs 220 upward through slide pivots 190. As rear legs 220 slide upward through slide pivots 190 and pivots 180, front legs 210 pivot towards rear legs 220 such that legs 210 and 220 are substantially parallel and closely spaced to one another. FIG. 5 illustrates a folding chair in the folded state.

[0028] Lifting center rung 170 up towards top rung 130 simultaneously releases any tension applied by the upholstery to upper rung 130 and center rung 170. This allows rungs 130 and 170 to fold, the right and left segments (e.g. 170a, 170c, 130a, and 130c) of the rungs bending towards each other until the segments are substantially parallel to one another and substantially perpendicular to the center segments.

[0029] As rungs 130 and 170 fold, rear legs 220 move inwards towards each other, causing the top end of each crossrail 110 to slide upward along rear leg 220 via pivot 180, and the bottom end of each crossrail 110 to slide downwards along rear legs 220 via the attachment to slide pivot 190. Since crossrails 110 also may be pivotally connected at their approximate center, crossrails 110 pivot with respect to one another until each crossrail 110 is substantially parallel to the other, and substantially vertical with respect to the ground.

[0030] Referring to FIG. 5, the sides of chair 100 fold in towards each other, creating a very compact folded state, in which side rails 230, back supports 140, rear legs 220, front legs 210, crossrails 110, and armrests 160 are all substantially parallel and closely spaced to one another. FIG. 5 depicts the folded state of chair 100.

[0031] It has been shown that folding chair 100, by making use of collapsible rungs 130 and 170, folds compactly in two directions while providing better back and seat support than is found in the prior art. The stability of chair 100 is enhanced by upholstery 410, which forces top rung 130 downward and center rung 170 rearward, making chair 100 very rigid in the open position, especially when being used. Moreover, by allowing the seat frame and backrest frame to slide along the rear leg via slide pivot 190 and pivot 180, the rear leg can be extended past the back for greater stability without sacrificing compactness.