Collapsible table

[0001] This invention relates to collapsible furniture. More particularly, the invention relates to a lightweight table having legs which may collapse from a use position to a storage position.

[0002] Collapsible or foldable tables are widely used to provide temporary table space in multipurpose meeting rooms, such as banquet halls and hotel conference rooms. Collapsible tables are popular for such applications because they may be folded into a relatively flat package which provides for ease of storage between uses.

[0003] Prior collapsible table designs have been lacking for numerous reasons. Some tables, such as those having table tops made of solid wood or particle board, are extremely heavy and unwieldy, causing difficulty in transport and setup. Such heavy tables can also cause severe damage or injury if dropped during transport. Lighter-weight table designs generally employ support structures that become unstable when a significant amount of weight is placed on the table top. To overcome stability problems, some table designs employ folding support mechanisms that are complicated and costly to manufacture.

[0004] What is needed, therefore, is a folding table which is sturdy, relatively light-weight, and relatively inexpensive to manufacture.

[0005] The above and other needs are met by a collapsible table having a table top, such as may be formed by blow molding, with a substantially planar top surface and a bottom surface opposite the top surface. Formed into the bottom surface of the table top are opposing first and second channels. Disposed within the first channel is a first pivot bar, and disposed within the second channel is a second pivot bar. The table includes opposing first and second frame members secured to the bottom surface of the table top. Disposed between and pivotally attached to the first and second frame members are opposing first and second leg assemblies which are movable between a use position and a storage position. To maintain the first leg assembly in the use position, the table has a first support assembly which includes a first brace structure and a first support bar. The first brace structure has a first central pivotal attachment point, and one or more first distal pivotal attachment points attached to the first leg assembly. The first support bar has a first end which is pivotally attached to the first pivot bar and a second end which pivotally attached to the first central pivotal attachment point of the first brace structure. To maintain the second leg assembly in the use position, the table has a second support assembly which includes a second brace structure and a second support bar. The second brace structure has a second central pivotal attachment point, and one or more second distal pivotal attachment points attached to the second leg assembly. The second support bar has a first end which is pivotally attached to the second pivot bar and a second end which pivotally attached to the second central pivotal attachment point of the first brace structure.

[0006] In a most preferred embodiment, the first and second pivot bars comprise substantially cylindrical rods, and the first and second channels each have a channel surface with an inside diameter substantially equivalent to the outside diameter of the first and second pivot bars.

[0007] Also in preferred embodiments, the bottom surface of the table top has opposing first and second projections separated by a separation distance. The first channel preferably has a first channel portion formed in the first projection, and a second channel portion formed in the second projection opposite the first channel portion. The first pivot bar is disposed within the first and second channel portions of the first channel, and spans the separation distance between the first and second projections. The second channel preferably has a third channel portion formed in the first projection, and a fourth channel portion formed in the second projection opposite the third channel portion. The second pivot bar is disposed within the third and fourth channel portions of the second channel, and spans the separation distance between the first and second projections.

[0008] In another aspect, the invention provides a method for manufacturing a collapsible table. The method includes forming a table top having a substantially planar top surface, a bottom surface opposite the top surface, and opposing first and second channels in the bottom surface. The method includes securing opposing first and second frame members to the bottom surface of the table top, and pivotally attaching first and second leg assemblies to the first and second frame members, such that the first and second leg assemblies are movable between a use position and a storage position.

[0009] According to the preferred method, a first brace structure is provided, having a first central pivotal attachment point and at least one first distal pivotal attachment point. The first distal pivotal attachment point of the first brace structure is pivotally attached to the first leg assembly. The method includes providing a first support bar having first and second ends. The second end of the first support bar is pivotally attached to the first central pivotal attachment point of the first brace structure. The method further includes providing a first pivot bar, pivotally attaching the first end of the first support bar to the first pivot bar, and inserting the first pivot bar into the first channel in the bottom surface of the table top.

[0010] A second brace structure is provided, having a second central pivotal attachment point and at least one second distal pivotal attachment point. The second distal pivotal attachment point of the second brace structure is pivotally attached to the second leg assembly. The method includes providing a second support bar having first and second ends. The second end of the second support bar is pivotally attached to the second central pivotal attachment point of the second brace structure. The method further includes providing a second pivot bar, pivotally attaching the first end of the second support bar to the second pivot bar; and inserting the second pivot bar into the second channel in the bottom surface of the table top.

[0011] Further advantages of the invention are apparent by reference to the detailed description when considered in conjunction with the figures, which are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein:

[0012] FIG. 1 is a perspective view of the top of a collapsible table according to a preferred embodiment of the invention;

[0013] FIG. 2 is an exploded view of a collapsible table according to a preferred embodiment of the invention;

[0014] FIG. 3 is a perspective view of the bottom of a collapsible table according to a preferred embodiment of the invention;

[0015] FIG. 4 depicts a structure for pivotally attaching support bars to a bottom surface of a table top of a collapsible table according to a preferred embodiment of the invention;

[0016] FIG. 5 is a perspective view of the top of a collapsible table according to an alternative embodiment of the invention;

[0017] FIG. 6 is an exploded view of a collapsible table according to an alternative embodiment of the invention;

[0018] FIG. 7 is a perspective view of the bottom of a collapsible table according to an alternative embodiment of the invention;

[0019] FIG. 8 depicts a structure for pivotally attaching support bars to a bottom surface of a table top of a collapsible table according to an alternative embodiment of the invention; and

[0020] FIGS. 9A-C depict orthogonal views of an attachment bar used to pivotally attach a support bar to a bottom surface of a table top of a collapsible table according to an alternative embodiment of the invention.

[0021] Referring now to FIGS. 1-4, there is generally depicted a collapsible table 10 according to a preferred embodiment of the present invention. The table 10 includes a table top section 12 having a substantially planar top surface 12a and an opposing bottom surface 12b. In the preferred embodiment, the table top 12 is formed from a thermoplastic material, such as by a molding process, such as blow molding. This process provides a sturdy, yet lightweight table top 12 that is well suited for applications where ease of handling and transport are important. Though thermoplastic is the preferred material for the table top 12, one skilled in the art will appreciate that the table top 12 could be formed of other materials, such as fiberglass or other composite materials, wood, or metal. Thus, the scope of the invention is not limited to any particular material or forming method for the table top 12. In a preferred embodiment, the table top 12 is about 48 inches long and about 24 inches wide.

[0022] Although the table top 12 depicted in FIGS. 1-3 is rectangular, it should be appreciated that the structures described herein are applicable to table tops that are circular, elliptical, or any other shape. Thus, the scope of the invention is not limited to any particular shape of the table top 12.

[0023] As depicted in FIGS. 2 and 3 the preferred embodiment of the table top 12 includes a peripheral lip 13 extending outward from the bottom surface 12b. Preferably, the lip 13 is formed during the molding of the table top 12, and is thus an integral and continuous extension of the bottom surface 12b. Attached to the lip 13 on opposing sides of the bottom surface 12b are a pair of frame members 18 and 20, also referred to herein as a first frame member 18 and a second frame member 20. Preferably, the first and second frame members 18 and 20 are secured to the lip 13 by screws 15. In the preferred embodiment, the frame members 18 and 20 are formed of metal, such as steel, and are generally L-shaped in cross-section. As depicted in FIG. 2, the frame members 18 and 20 preferably include lip portions 18a and 20a which are received in channels 13a and 13b in the lip 13 when the frame members 18 and 20 are attached to the bottom surface 12b of the table top 12. This interface between the lip portions 18a-20a and the channels 13a-13b tends to prevent lateral motion between the frame members 18 and 20 and the table top 12, thereby increasing the structural rigidity of the table 10.

[0024] As shown in FIG. 2, adjacent each end of the first frame member 18 are substantially circular apertures 18b andl8c, and adjacent each end of the second frame member 20 are substantially circular apertures 20b and 20c. The purpose of the apertures 18b-18c and 20b-20c is described below.

[0025] As depicted in FIGS. 1-3, the table 10 includes a pair of opposing leg assemblies 14 and 16, also referred to herein as a first leg assembly 14 and a second leg assembly 16. The first and second leg assemblies 14 and 16 are pivotally attached to and between the first and second frame members 18 and 20. In the preferred embodiment, the first leg assembly 14 comprises a pair legs 14a and 14b, each attached at one end to a cross member 14d. The second leg assembly 16 preferably comprises a pair legs 16a and 16b, each attached at one end to a cross member 16d. To provide lateral support, a brace 14c is provided between the legs 14a and 14b, and a brace 16c is provided between the legs 16a and 16b. In the preferred embodiment, the legs 14a-14b and 16a-16b, the cross members 14d and 16d, and the braces 14c and 16c are formed of metal, such as steel. However, it will be appreciated that other materials could be used, such as wood or composite materials. The attachment of the legs 14a-14b and 16a-16b to the cross members 14d and 16d, and the braces 14c and 16c to the legs 14a-14b and 16a-16c, is preferably accomplished by welding.

[0026] As shown in FIGS. 2 and 3, opposing ends of the cross member 14d penetrate the apertures 18c and 20c in the opposing frame members 18 and 20. Similarly, opposing ends of the cross member 16d penetrate the apertures 18b and 20b in the frame members 18 and 20. The diameters of the apertures 18b-18c and 20b-20c are preferably large enough to allow free rotation of the ends of the cross members 16d and 14d therein. In this manner, the leg assemblies 14 and 16 may be rotated between a use position and a storage position. In FIG. 3, the leg assembly 14 is depicted in the use position, and the leg assembly 16 is depicted in the storage position.

[0027] To maintain the first and second leg assemblies 14 and 16 in the use position, the table 10 includes first and second support assemblies 21 and 23. As depicted in FIGS. 2 and 3, the first support assembly 21 includes a first brace structure 28 and a first support bar 24, and the second support assembly 23 includes a second brace structure 26 and a second support bar 22. In the preferred embodiment of the invention, the first brace structure 28 comprises two opposing brackets 28a and 28b, and the second brace structure 26 comprises two opposing brackets 26a and 26b. Preferably, the bracket 28a is pivotally attached at one end to the leg 14a of the leg assembly 14 and at the other end to the second end 24b of the support bar 24. The bracket 28b is pivotally attached at one end to the leg 14b and at the other end to the second end 24b of the support bar 24. Similarly, the bracket 26a is pivotally attached at one end to the leg 16a of the leg assembly 16 and at the other end to the second end 22b of the support bar 22. The bracket 26b is pivotally attached at one end to the leg 16b and at the other end to the second end 22b of the support bar 22. The pivotal attachment of the brackets 28a-b and 26a-b to the leg assemblies 14 and 16 is preferably accomplished using bolts 29, and pivotal attachment of the brackets 28a-b and 26a-b to the support bars 24 and 22 is preferably accomplished using bolts 27. In the preferred embodiment, the brackets 28a-28b and 26a-26b are formed of steel bar stock. The first and second support bars 24 and 22 are preferably formed of tubular steel which has been pressed flat at the ends 24a-24b and 22a-22b. The first ends 24a-22a of the first and second support bars 24 and 22 are pivotally coupled to the bottom surface 12b of the table top 12 in a manner described hereinafter.

[0028] As depicted in FIG. 2, extending outward from the bottom surface 12b of the table top 12 are a pair of opposing elongate projections 34 and 36, also referred to herein as first and second projections 34 and 36, which are separated by a gap 35. In the preferred embodiment, the projections 34 and 36 are formed during the molding of the table top 12, and are thus integral 5 and continuous extensions of the material which forms the bottom surface 12b of the table top 12. Within the first and second projections 34 and 36 are first and second channels 38 and 40. Preferably, the first channel 38 includes a first channel portion 38a formed in the first projection 34, and a second channel portion 38b formed in the second projection 36, where the first channel portion 38a is aligned with the second channel portion 38b. The second channel 40 includes a third channel portion 40a formed in the first projection 34, and a fourth channel portion 40b formed in the second projection 36, where the third channel portion 40a is aligned with the fourth channel portion 40b. Preferably, the channel portions 38a-b and 40a-b take the form of cylindrical grooves molded into the first and second projections 34 and 36.

[0029] In alternative embodiments, the channels 38 and 40 are formed completely within a single projection extending from the bottom surface 12b of the table top 12, or are formed directly in the bottom surface 12b.

[0030] As depicted in FIGS. 2, 3, and 4, the preferred embodiment of the table 10 includes a pair of pivot bars 30 and 32 which are preferably formed of tubular steel. The pivot bars 30 and 32 have an outer diameter which is substantially the same as, or preferably slightly less than, the inner diameter of apertures 22c and 24c in the first ends 22a and 24a of the first and second support bars 22 and 24. As shown in FIGS. 3 and 4, the pivot bar 30 penetrates the aperture 22c in the first support bar 22, and the pivot bar 32 penetrates the aperture 24c in the second support bar 24. Thus, the first and second support bars 22 and 24 are free to pivot about the first and second pivot bars 30 and 32, respectively, as the leg assemblies 14 and 16 rotate between the use and storage positions.

[0031] The outer diameter of the first and second pivot bars 30 and 32 is also substantially the same as, or slightly less than, the inner diameter of the first and second channels 38 and 40. In this manner, the first pivot bar 30 may be inserted into the first and second channel portions 38a-b of the first channel 38, and the second pivot bar 32 may be inserted into the third and fourth channel portions 40a-b of the second channel 40. Preferably, as depicted, the channel portions 38a-b and 40a-b are blind channels, that is, they do not extend completely through the projections 34 and 36. Thus, when the first and second pivot bars 30 and 32 are inserted into the channel portions 38a-b and 40a-b, the bars 30 and 32 are preferably captured in the axial direction, thereby preventing movement of the bars 30 and 32 in the axial direction.

[0032] As shown in FIG. 4, the projection 34 preferably includes lips 34a-b which partially overhang the first and third channel portions 38a and 40a, respectively. Similarly, the projection 36 preferably includes lips 36a-b which partially overhang the second and fourth channel portions 38b and 40b, respectively. The lips 34a-b and 36a-b serve to capture the pivot bars 30 and 32 so that they snap into place when inserted into the channel portions 38a-b and 40a-b. As shown in FIGS. 3 and 4, the pivot bars 30 and 32 are preferably secured in the channel portions 38a-b and 40a-b by fasteners, such as screws 44, 46, 48, and 50.

[0033] As depicted in FIG. 3, the pivotal motion of the first ends of the support bars 22 and 24 with respect to the pivot bars 30 and 32, and the pivotal motion of the brace structures 26 and 28 with respect to the support bars 22 and 24 and the leg assemblies 14 and 16, allows these structures to fold down substantially parallel to the table top 12. The gap 35 between the first and second projections 34 and 36 provides a space to accommodate the support bars 22 and 24 when the leg assemblies 14 and 16 are folded down into the storage position.

[0034] With reference to FIG. 3, the preferred embodiment of the invention includes lock rings 31, each having sufficient inner diameter to slide down over the second ends of the support bars 22b and 24b and over the attached ends of the brace structures 28 and 26 when the leg assemblies 14 and 16 are in the use position. The lock rings 31 serve to prevent the brace structures 26 and 28 from pivoting in relation to the support bars 22 and 24 when in the use position, thereby preventing an inadvertent collapse of the table 10.

[0035] As shown in FIG. 4, the preferred embodiment of the invention includes a handle 42 secured between and perpendicular to the pivot bars 30 and 32. In the preferred embodiment, the handle 42 is formed of tubular steel, and is secured at each end to the pivot bars 30 and 32 by welding. However, one skilled in the art will appreciate that the handle 42 could be attached to the pivot bars 30 and 32 by other means, such as using screws or other fasteners. Preferably, the handle has notches 42a and 42b at each end which straddle the ends 22a and 24a of the support bars 22 and 24. In this manner, the ends 22a and 24a of the support bars 22 and 24 are captured within the notches 42a and 42b to prevent lateral movement of the support bars 22 and 24 with respect to the pivot bars 30 and 32.

[0036] An alternative embodiment of the table 10 is depicted in FIGS. 5-7. Except for the shape of the leg assemblies 14 and 16, the structure of this embodiment is substantially the same as the structure of the first embodiment described above. The embodiment of FIGS. 5-7 is particularly well suited for a table having a higher length-to-width ratio, such as a banquet table. For example, the table top 12 depicted in FIGS. 5-7 is preferably about 72 inches long and about 30 inches wide.

[0037] Depicted in FIGS. 8 and 9A-C is a structure for pivotally attaching the first and second support bars 22 and 24 to the bottom surface 12b according to an alternative embodiment of the invention. This embodiment includes four attachment brackets 102, 104, 106, and 108 attached to the bottom surface 12b and to the frame members 18 and 20.

[0038] As shown in FIG. 8, two of the brackets 102 and 106 span one half of the bottom surface 12b, and the other two brackets 104 and 108 span the other half of the bottom surface 12b. Distal ends 102a and 106a of the brackets 102 and 106 penetrate a slot 20d in the frame member 20, and distal ends 104a and 108a of the brackets 104 and 108 penetrate a slot 18d in the opposing frame member 18. Proximate ends 102b, 104b, 106b, and 108b of the brackets 102, 104, 106, and 108 are secured to the bottom surface 12b, preferably using fasteners such as screws which pass through holes in attachment tabs 102c, 104c, 106c, and 108c and into the material of the bottom surface 12b.

[0039] FIGS. 9A, 9B, and 9C depict three orthogonal views of the attachment bracket 106. One skilled in the art will appreciate that the bracket 102 is a horizontal mirror image of the bracket 106, and the brackets 108 and 104 are vertical mirror images of the brackets 106 and 102, respectively. As shown in FIGS. 9A, 9B, and 9C, the bracket 106 has a pivot tab 106d with a through-hole 110 therein. When the brackets 106 and 108 are attached to the bottom surface 12b, the hole 110 in the pivot tab 106d is aligned with an opposing hole in the pivot tab 108d of the bracket 108. Similarly, when the brackets 102 and 104 are attached to the bottom surface 12b, a hole in the pivot tab 102d is aligned with an opposing hole in the pivot tab 104d of the bracket 104. The first end 22a of the support bar 22 is disposed between the pivot tabs 106d and 108d, with the aperture 22c (FIG. 2) aligned with the holes 110 in the pivot tabs 106d and 108d. The first end 24a of the support bar 24 is disposed between the pivot tabs 102d and 104d, with the aperture 24c (FIG. 2) aligned with the holes 110 in the pivot tabs 102d and 104d. Fasteners 112, such as bolts, penetrate the holes 110 in the pivot tabs 106d and 108d and the aperture 22c to pivotally attach the support bar 22 to the brackets. Similarly, fasteners 112 penetrate the holes 110 in the pivot tabs 102d and 104d and the aperture 24c to pivotally attach the support bar 22 to the brackets 102 and 104. Thus, as the leg assemblies 14 and 16 (FIG. 3) are moved between the use position and the storage position, the support bars 22 and 24 pivot about the fasteners 112.

[0040] Although it has been determined that brackets 102, 104, 106, 108 having the shapes as depicted in FIG. 8 provide a structurally secure means of attachment, it should be appreciated that the brackets 102, 104, 106, 108 could have other shapes. For example, instead of providing three alternating 90-degree bends as depicted in FIG. 9A, the brackets 102, 104, 106, 108 could be provided with two bends of 135 degrees, while leaving the ends of the brackets at the same relative positions. In that example, the brackets 102, 104, 106, 108 would come together in a substantially diamond-shaped arrangement, rather than the rectangular arrangement depicted in FIG. 8. Thus, the scope of the invention is not limited to any particular shape of the attachment brackets 102, 104, 106, and 108.

[0041] The foregoing description of preferred embodiments for this invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the invention and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as is suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.