Patent Publication Number: US-7588295-B2

Title: Legged support

Description:
BACKGROUND OF THE INVENTIONS 
   1. Field of the Inventions 
   The present inventions relate to legged supports for furniture and, more particularly, stools, chairs, other seating devices, tables and the like. 
   2. Description of the Related Art 
   A variety of stools, chairs, other seating devices and other furniture with legs are well known. In order to prevent the undesirable spreading or other movement of such legs, it is often necessary to structurally reinforce the lower ends of the legs. For example, one or more intermediate or lower support members that brace the legs can be used. 
   However, such support members can complicate the manufacture, packaging, transport, assembly and overall design of a stool or other furniture with legs. Moreover, it may be aesthetically displeasing to include such support members. Therefore, it is desirable to provide a simple, reliable, effective and secure base for the structural reinforcement of the legs. 
   SUMMARY OF THE INVENTIONS 
   One aspect of at least one of the inventions disclosed herein includes a tension ring and two or more legs that are attached to the tension ring. Tensile forces created by the tendency of the legs to move relative to the tension ring are transferred to the tension ring where they are counteracted by opposing tensile forces. Thus, the tension ring can help prevent spreading, rotation or other undesirable movement of the legs. 
   According to one arrangement of at least one of the inventions disclosed herein, a support assembly comprises a tension ring with an outer surface, two or more legs and a frame positioned above the tension ring and the legs. Each leg comprises an upper end and a lower end, with the lower end configured to contact a lower support surface, such as a floor. The frame contacts each leg in at least one contacting location situated between the upper end and the lower end of the leg. The tension ring is attached to each leg at a location proximate to the upper end of each leg, and the frame is configured to transfer a force to the legs at the contacting locations. Further, movement of the legs relative to the tension ring causes tensile forces to be exerted on the tension ring. 
   According to another arrangement of at least one of the inventions disclosed herein, support assembly additionally comprises one or more support members that are configured to connect the lower ends of the legs so as to provide further reinforcement of the legs. In another embodiment, the legs are attached to the tension ring at locations that are substantially equally spaced from each other. In other embodiments, four legs are attached to the tension ring. In still other embodiments, the seating assembly further comprises a cushion which is positioned above the frame. 
   In accordance with a further aspect of at least one of the inventions disclosed herein, the tension ring has a generally square shape. In another embodiment, the tension ring has a generally circular shape. In other embodiments, the legs are attached to the tension ring using one or more fasteners. In yet another embodiment, the legs are attached to the tension ring using one or more welds. 
   In accordance with a further aspect of at least one of the inventions disclosed herein, the legs have a split design in which at least a portion of the legs have at least two support members. In another embodiment, the legs are curved into a substantially S shape. In another embodiment, the legs are curved into a substantially Z shape. In one embodiment, the frame is secured to the leg at a location proximate to the contacting location. In yet another embodiment, the frame is secured to the leg using one or more fasteners. 
   In accordance with a further aspect of at least one of the inventions disclosed herein, the lower ends of the legs contact the lower surface proximate to a location directly below the contacting locations. In another embodiment, the tensile forces exerted on the tension ring substantially balance each other. 
   In accordance with a further aspect of at least one of the inventions disclosed herein, a support assembly comprises a tension ring, at least two legs and a frame positioned above the tension ring and the legs. The legs comprise a first end that is connected to the tension ring, and a second end that is configured to contact a lower surface. The frame contacts each leg in at least one contacting location, which is situated between the first end and the second end of each leg. The frame is configured to transfer a force to the legs at the contacting locations, and a movement of the legs relative to the tension ring causes tensile forces to be exerted on the tension ring. In other embodiments, the tension ring has a generally square shape. In yet another embodiment, the tension ring has a generally circular shape. 
   In accordance with a further aspect of at least one of the inventions disclosed herein, a method of reinforcing the legs of a furniture item comprises the steps of providing a tension ring, connecting the first ends of the legs to the tension ring and positioning a frame above the tension ring and the legs. The legs include a second end which is located opposite of the first end and which is configured to contact a lower surface. The frame contacts each leg in at least one contacting location, which is situated between the first end and the second end of each leg. The frame is configured to transfer a force to the legs at the contacting locations. Further, a movement of the legs relative to the tension ring causes tensile forces to be exerted on the tension ring so as to prevent the legs from moving relative to one another. 
   In accordance with a further aspect of at least one of the inventions disclosed herein, the method involves reinforcing the legs of a stool. In another embodiment, the method involves reinforcing the legs of a table. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, aspects and advantages of the inventions disclosed herein are described below with reference to the drawings of a preferred embodiment, which is intended to illustrate and not to limit the inventions. The drawings comprise the following figures: 
       FIG. 1A  illustrates a perspective view of a stool according to one embodiment. 
       FIG. 1B  illustrates a perspective view of a stool according to another embodiment. 
       FIG. 2  illustrates an exploded perspective view of a stool with various components detached according to yet another embodiment. 
       FIG. 3  illustrates a bottom view of the stool of  FIG. 1A . 
       FIG. 4  illustrates a bottom view of a stool according to a different embodiment. 
       FIG. 5  is a side elevation view of the stool of  FIG. 1A . 
       FIG. 6A  is a side elevation view of a furniture leg according to one embodiment. 
       FIG. 6B  is a side elevation view of the leg in  FIG. 6A . 
       FIG. 6C  is a detailed perspective view of the upper end of the leg according to one embodiment. 
       FIG. 7  is a side elevation view of a stool illustrating the various forces and moments acting on the stool according to one embodiment. 
       FIG. 8  is a detailed side elevation view of the stool in  FIG. 7 , illustrating the forces exerted on the tension ring. 
       FIG. 9  schematically illustrates the forces exerted on the tension ring of  FIG. 8 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The legged support and the various systems and features associated with it are described in the context of a stool because they have particular utility in this context. However, the legged support and methods described herein, as well as their various systems and features, can be used in other contexts as well, such as, for example, but without limitation, devices and structures that include legs or other similar support members whose movement can benefit from additional reinforcement, such as, for example, seating devices, tables, desks, platforms and the like. 
   With reference to  FIG. 1 , a stool  10  can include a tension ring  20 , a plurality of legs  30 , a frame  50  and a cushion  60 . As is discussed in greater detail below, the use of the tension ring  20  can enhance the reinforcement of the legs, which, in some embodiments, can prevent the legs from undesirably moving relative to one another (e.g., spreading apart, coming closer together, etc.) without the need for additional supports directly connecting the lower ends of the legs to each other. 
   As used herein, the terms “stool,” “chair,” “seating device,” and “seating assembly” are used interchangeably. Further, as used herein, the term “ring” refers to a member having a generally circular, oval, elliptical, triangular, square, rectangular, other polygonal or any other shape. The ring can have one or more inner openings. For example, the ring can be shaped like a toroid, hook, frame or the like. The cross sectional shape of the ring&#39;s structural members can be circular, oval, elliptical, triangular, square, rectangular, other polygonal or any other shape. In addition, the ring can include cross members or any other features. 
   The exploded view in  FIG. 2  illustrates the general orientation of the various stool components that can be used. In the depicted arrangement, the stool includes four legs  30 , each of which attaches to a different side of a four-sided tension ring  20 . It will be appreciated that more or fewer legs  30  can be attached to the tension ring  20 . 
   The tension ring  20  can be constructed of one or more rigid materials having favorable tensile strength properties, such as, for example, steel, iron, aluminum, other metals and metal alloys, plastic, wood or the like. In addition, any other material types can be used, including fiberglass, other composite and the like. 
   In  FIGS. 2 and 3 , the tension ring  20  has a substantially square or rectangular shape. Alternatively, however, the tension ring  20  can have a circular, oval, elliptical, polygonal or other shape. For example,  FIG. 4  illustrates one embodiment of a circular tension ring  20 B, to which are attached four legs  30 B. 
   In  FIGS. 2 through 4 , the depicted tension rings  20  include relatively large inner openings  24 . However, in other embodiments, the inner opening  24  can be smaller or larger than illustrated. Furthermore, the tension ring  20  can have additional openings or no openings at all. For instance, the tension ring  20  can be formed from a steel plate or a section of another rigid material so that the tension ring  20  can be a solid or a substantially solid member. 
   The cross-sectional shape of the tension ring  20  can be rectangular, polygonal, circular, elliptical, oval or the like. Furthermore, the structural components that comprise the tension ring  20  can be solid or hollow. For example, the tension ring  20  can be formed by a steel square or tube formed into a closed shape (e.g., circle, square, etc.). In other embodiments, the tension ring  20  can be manufactured from one or more angles, channels and/or other structural members. The tension ring  20  can be formed into a desired shape using one or more methods, such as, for example, bending, molding, forging, rolling, casting, machining or the like. Alternatively, two or more pieces can be welded, fastened, glued or otherwise connected to one another to create the desired shape of the tension ring  20 . 
   With continued reference to  FIG. 2 , the tension ring  20  can include one or more cross members  22  (e.g., braces, struts, etc.) which can enhance the ability of the tension ring  20  to resist forces, moments and other stresses to which it can be exposed. The cross members  22  can be welded, bolted, glued or otherwise connected to the desired locations on the tension ring  20 . As discussed below with respect to tensile force resistance, it can be desirable for the tension ring  20  to be symmetrical in order to more adequately balance, opposing forces. 
   Specific leg assemblies, according to some embodiments, are described in greater detail below. However, any type of leg suitable for a stool, chair or other furniture can be used. 
   With continued reference to  FIG. 2 , the stool  10  can include a plurality of legs  30  which are connected to the tension ring  20  at or near the upper end of the legs  30 . Like with other stool components, the legs  30  can be manufactured from one or more rigid materials, such as, for example, steel, iron, aluminum, fiberglass, plastic, wood or the like. In some embodiments, as illustrated in  FIGS. 1A ,  2 ,  5  and  6 A, an upper portion of each leg  30  can be substantially horizontal and aligned with the tension ring  20  to which it attaches. However, it will be appreciated that the shape of the legs  30  can vary depending on the furniture type, the desired decorative style and/or other considerations of the specific application. 
   For example, the leg illustrated in  FIG. 6A  has a curved S-shape between the substantially horizontal upper portion and the foot member  34 . In contrast, the legs  30  illustrated in  FIG. 2  include sharper transitions which form three distinct regions. In such an arrangement, the profile of the legs can have a Z shape. However, the legs can be differently configured or shaped with more or less intricate designs, as desired or required by a particular application. 
   With reference to  FIG. 6B , the leg  30  has a split design, meaning that it comprises two or more separate support members  32 . In the illustrated embodiment, the two support members  32  are joined to each other near the lower portion of the leg  30  using welds  33 A,  33 B. However, additional welds and/or other types of connection methods can be used to attach the separate support members  32  to one another. 
   For example, the support members  32  can be joined to each other using one or more bolts, screws or other fasteners, pins, adhesives, clips, etc. In other embodiments, the legs  30  can be formed, cast, bent or otherwise manufactured into a desired split design to form a single member. Moreover, the legs  30  can include more or fewer support members  32  than shown and discussed herein. For instance, in a simple arrangement, the leg  30  can comprise only a single structural member. 
   The split design of the leg  30  can provide multiple connection points between the tension ring  20  and the upper portion of the leg  30 . Such configurations can offer a more secure connection between the legs  30  and the tension ring  20  to better resist shear, torsion and other forces exerted on the stool or other furniture. Additional support members  32  can be included to provide more connection points between the leg and the adjacent tension ring  20 . Further, the split design can be configured to advantageously offer certain aesthetic and architectural benefits. 
   The legs  30 , which can be hollow or solid, can have any suitable cross-sectional shape, including square, rectangular, polygonal, circular, oval, elliptical and the like. The length of the legs  30  can vary depending on the desired height of the stool or other furniture. Regardless of their materials of construction, size, shape, dimensions and other properties, the legs  30  can be configured to withstand the forces, moments and other stresses to which they can be exposed. 
   With continued reference to  FIGS. 6A and 6B , an upper portion of each leg  30  can include an intermediate tab member  36  to which the frame  50  ( FIG. 2 ) or other member situated above the leg  30  can be attached. In the illustrated embodiment, the intermediate tab member  36  includes two openings  38 A,  38 B which are configured to receive bolts, screws or other fasteners. Such openings can be used to securely fasten the tab member  36  (and consequently the leg  30 ) to the frame  50  or other above-situated member. 
   In  FIGS. 6A and 6B , the intermediate tab member  36  can be welded to the adjacent support members  32  of the leg  30 . Further, the tab member  36  can be situated in an upright position such that bolts or other fasteners (not shown) inserted through the openings  38 A,  38 B have a substantially horizontal orientation. 
   In other embodiments, however, the intermediate tab member  36  can be connected to the leg  30  using one or more other methods. Further, the tab member  36  can comprise more or fewer openings than depicted in  FIG. 6B . In yet other arrangements, an upper frame  50  or other member can be configured to connect directly to the leg  30  without the need for a intermediate tab member  36 . For example, one or more openings for receiving a bolt or other fastener can be provided directly in the leg  30 . Alternatively, the leg  30  can be joined to the adjacent frame  50  or other member using other attachment methods, such as, for example, a pins, clips, adhesives, welds and the like. 
   As illustrated in  FIGS. 3 through 5 , the upper end of the legs  30  can be attached to an adjacent surface of the tension ring  20 . The legs  30  can be connected to the tension ring  20  using one or more welds, bolts, screws, other fasteners, adhesives, clips, pins, hinges or the like. For example, in the embodiment depicted in  FIG. 2  and detailed in  FIG. 6C , a leg  30  can be connected to the tension ring  20  using one or more fasteners (not shown). 
   The leg  30  can comprise an end plate  40  which can be welded or otherwise connected to the support members  32  of the leg  30 . In  FIG. 6C , the end plate  40  and the adjacent surface of the tension ring  20  include four openings that can be aligned with one another. It will be appreciated that more or fewer openings can be included in the end plate  40  and/or the tension ring  20 . 
   Alternatively, one or more fasteners can be used to connect the legs  30  directly to the tension ring  20  without the need for an end plate  40 . For example, as illustrated in  FIG. 3 , the support members  32  can comprise threaded end openings through which fasteners F can be secured. Thus, fasteners F can be passed from the inside of the tension ring  20 , through holes in the tension ring, and secured into the corresponding openings of the support members  32 . 
   With continued reference to  FIG. 2 , a frame  50  can be positioned on top of the legs  30  and the tension ring  20 . When viewed from above, the illustrated frame  50  has an octagonal shape. Moreover, the frame  50  can include an upper frame member  52 A and a lower frame member  52 B, which can be joined to each other by one or more vertical frame members  54 . It will be appreciated that the shape, height, size, dimensions and other characteristics of the frame  50  can be different than illustrated in  FIG. 2 . For example, in one embodiment, the frame  50  can be circular and substantially flat. In other embodiments, one or more of the frame members  52 A,  52 B,  54  can have one or more other features, such as, for example, openings, holes, struts, decorative elements or the like). Alternatively, the frame members can be solid (e.g., plate with few or no openings). 
   The frame  50  can be constructed of one or more rigid materials, such as, for example, steel, iron, aluminum, fiberglass, plastic, wood or the like. As discussed above, the frame  50  can be as simple as a single rigid plate. Alternatively, the frame  50  can have a more intricate design. For example, the frame  50  can comprise a plurality of structural members, such as rods, channels, angles, squares and/or the like, that can be rigidly connected to one another. In addition, as shown in  FIG. 5 , the frame  50  can include one or more ornamental features  57  that modify the appearance of the stool  10  or other furniture. 
   With continued reference to  FIG. 5 , when properly positioned above the legs  30 , the frame  50  can contact each leg  30  in at least one contact location  58 . As discussed in greater detail below, forces can be transferred from the frame  50  to the legs  30  at these contact locations  58 . In addition, as described above with reference to  FIGS. 6A and 6B , the legs  30  can include an intermediate tab member  36  that secures the frame  50  to the legs  30 , thereby preventing relative movement between these components. 
   Furthermore, the stool  10  can comprise a cushion  60  or similar member that can be positioned above the frame  50 . However, in some embodiments, a single member can take the place of both the frame  50  and the cushion  60 . In arrangements where the furniture is not a seating device, the cushion  60  can be replaced with another component. For example, a rigid tabletop, desktop, platform or the like can be secured to the frame  50 . 
   With continued reference to  FIGS. 2 and 3 , the frame  50  can include one or more frame tabs  58  to which an adjacent cushion  60  or similar member can attach. The frame tabs  58  can include an opening  59  through which a bolt, screw or other fastener can be passed in order to join the frame  50  to the cushion  60 . In other embodiments, the frame  50  and cushion  60  can be connected by other methods, such as, for example, by utilizing clips, pins, adhesives, welds and/or the like. Alternatively, it can desirable to allow for relative movement between the frame  50  and the cushion  60 . For example, a stool  10  can be configured so that the cushion  60  rotates or swivels relative to the adjacent frame  50 . 
   The stool  10  or other furniture can include one or more other features. With reference to  FIG. 1B , the stool  10 A can comprise a plurality of restriction members  70  that connect the tension ring  20  to the bottom of the legs  30 . The restriction members  70  can be rigid, semi-rigid and/or flexible. For example, a metal rod, dowel, strut, angle, wire or the like can be used. The restriction members  70  can be sized and otherwise configured to provide further assurance that the legs  30  will not move beyond a desired range. In some embodiments, additional members (not shown) can directly connect the lower ends of the legs  30  to provide further reinforcement against the outward spreading of the legs  30 . In other arrangements, the stool  10  can be equipped with a backrest, armrests or the like. Moreover, the legs  30  can include wheel assemblies permitting the stool  10  or other furniture to be easily rolled relative to a bottom surface. 
     FIG. 7  schematically illustrates the forces and moments that can act on the stool  10 . This simplified diagram is provided to demonstrate the interaction between the legs  30 , tension ring  20  and frame  50  when a distributed vertical force V is applied to the stool  10 . As illustrated, the legs  30  can be connected at opposite ends of the tension ring  20 . A vertical force V applied to the frame  50  of the stool  10  is transferred to the legs  30  at the contact locations  58 , which, in the depicted embodiment, are the sole points of contact between the frame  50  and legs  30 . Depending on the location of the legs relative to the contact locations, the length of the legs, the magnitude of the vertical force V and/or other factors, a moment  120  can be created in the legs  30  which causes the legs  30  to tend to spread outwardly in a direction generally away from the tension ring  20 . An opposite moment can also be exerted on the legs (e.g., if the legs are urged toward one another). 
     FIGS. 8 and 9  illustrate the forces imparted on the tension ring  20  as a result of the moment  120  and/or the movement of the legs  30  relative to the tension ring  20 . By way of example, the resultant forces F R1 , F R2  are depicted with arrows. In such embodiments, opposing tensile forces F X1 , F X2  are exerted on the tension ring  20 . Such forces, which can be equal or substantially equal in magnitude, act to balance each other. Thus, the tension ring  20  desirably comprises the necessary tensile strength properties to resist the tensile forces F X1 , F X2  exerted on it by the adjacent legs  30 . Consequently, the legs  30  can be desirably positioned in a symmetrical pattern around the tension ring  20  so as to counteract the tensile forces created by each leg  30 . This can be accomplished by equally spacing out the legs around the tension ring, irrespective of the total number of legs. For example, if a stool  10  comprises four legs  30 , the legs can be positioned 90 degrees from each other. Further, if a stool  10  includes only three legs  30 , the legs  30  can be positioned 120 degrees apart from each other. 
   Moreover, the vertical components F Y1 , F Y2  of the respective resultant forces F R1 , F R2  can generate a vertical movement in the tension ring  20 . However, such a vertical movement can be minor due, in part, to the connection between the legs  30  and the frame  50  located above it ( FIG. 7 ). The stiffness, slenderness ratio and other structural characteristics of the legs  30  can also affect the extent to which the tension ring  20  moves vertically. The forces illustrated in  FIGS. 8 and 9  are provided to indicate the general direction of the force vectors. As such, the relative size and exact direction of the component force vectors can be different than shown. 
   If the moment is opposite of that illustrated in  FIGS. 8 and 9 , the legs  30  can tend to move closer together upon the application of a vertical force on the stool  10 . Consequently, the forces exerted on the tension ring  20  will also be different than those depicted in  FIGS. 8 and 9 . For example, the vertical force components on the tension ring  20  are likely to act in the opposite direction, tending to urge, the tension ring  20  upwardly. However, the horizontal force components will still exert tensile stresses on the tension ring  20  in the same direction illustrated in  FIGS. 8 and 9 . Therefore, the tension ring  20  can be used to balance the tensile forces exerted upon it by the adjacent legs, regardless of whether the legs of the stool  10  are being urged closer together or further apart. As a result, the legs  30  can even be attached to the tension ring using a hinged connection, as long as the hinge is correctly installed to maintain the legs in contact with the tension ring (not rotate) when a load is exerted on the stool. This is possible because the direction of the moment acting on the legs when a vertical force is exerted on the stool will likely remain consistent for a particular design. 
   The various embodiments of the tension ring described herein can be used to eliminate the need for a ring or other restraining member near the middle or lower portion of the legs. As described above, the ability of the tension ring to balance out the tensile forces generated by the torquing of the legs can reduce or eliminate the movement of the legs relative to each other. This can simplify the design of a stool or other furniture member. Further, the tension ring can be used to improve the aesthetic appearance of a stool or other furniture, especially since the tension ring can be hidden beneath a frame or similar member. Incorporation of the tension ring into a furniture design can also facilitate more efficient manufacturing, packaging, transport, assembly and other related activities. 
   Although these inventions have been disclosed in the context of a certain preferred embodiment and examples, it will be understood by those skilled in the art that the present inventions extend beyond the specifically disclosed embodiment to other alternative embodiments and/or uses of the inventions and obvious modifications and equivalents thereof. In addition, while several variations of the inventions have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments or variations can be made and still fall within the scope of the invention. It should be understood that various features and aspects of the disclosed embodiment can be combined with or substituted for one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present inventions herein-disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.