Public Patent

Engineered bamboo furniture with mortise and tenon joints

Bamboo Furniture Patent Ideas Abstract

Engineered bamboo furniture having components joined with mortise and tenon joints is made by fabricating the components of engineered bamboo, forming corresponding pairs of complementary mortise and tenon joints on the components, and assembling the parts into a finished article of furniture by bonding the respective tenons of the components in the corresponding mortises of the components with an adhesive. The engineered bamboo material is made by treating elongated flat strips of bamboo with high temperature steaming and drying, carbonizing, dehydrating and starch-removal processes, and then laminating the strips to each other using an adhesive under high pressure to form structural sheets or panels of different types, e.g., face-bonded sheets and/or edge-bonded sheets, which can be laminated to each other to form board-like and plywood-like structures. The mortise and tenon joints on the components may be square, trapezoidal, circular, elliptical, or arcuate trapezoids.

Bamboo Furniture Patent Ideas Claims

1. A method for making engineered bamboo furniture joined together with mortise and tenon joints, the method comprising: making furniture components of engineered bamboo; forming corresponding pairs of complementary mortise and tenon joints on the components; and, assembling the components into a finished article of furniture by bonding the respective tenons of the components in the corresponding mortises of the components with an adhesive.

2. An article of furniture made in accordance with the method of claim 1.

3. The method of claim 1, wherein the article of furniture comprises a table, a chair, a cabinet, a bed or a shelf.

4. The method of claim 1, wherein making furniture components comprises: providing flat, elongated strips of bamboo, each strip having a pair of opposite wide faces and a pair of opposite narrow edges; treating the strips by high temperature steaming, high temperature drying, carbonizing, dehydrating and starch removal processes; and, laminating the strips together with an adhesive under high pressure.

5. The method of claim 4, wherein laminating the bamboo strips together comprises: depositing an adhesive on the opposite wide faces of the strips; arranging the strips in a layer such that their respective wide faces are disposed in opposition to each other and respective longitudinal fibers of the strips are disposed parallel to each other and, adhering the respective opposing wide faces of the strips to each other to form a face-bonded sheet.

6. The method of claim 4, wherein laminating the bamboo strips together comprises: depositing an adhesive on the opposite narrow edges of the strips; arranging the strips in a layer such that their respective narrow edges are disposed in opposition to each other and respective longitudinal fibers of the strips are disposed parallel to each other and, adhering the opposing narrow edges of the strips to each other to form an edge-bonded sheet.

7. The method of claim 6, further comprising laminating a plurality of the edge-bonded sheets together to form a panel.

8. The method of claim 7, wherein the respective longitudinal fibers of the bamboo strips of each sheet are disposed parallel to the respective longitudinal fibers of the bamboo strips of adjacent sheets.

9. The method of claim 7, wherein the respective longitudinal fibers of the bamboo strips of each sheet are disposed perpendicular to the respective longitudinal fibers of the bamboo strips of adjacent sheets.

10. A method for making engineered bamboo furniture components, the method comprising: providing flat, elongated strips of bamboo, each strip having longitudinal fibers, a pair of opposite wide faces and a pair of opposite narrow edges; treating the strips by high temperature steaming, high temperature drying, carbonizing, dehydrating and starch removal processes; depositing an adhesive on the opposite wide faces of a first group of the strips; arranging the first group of strips in a layer such that their respective wide faces are disposed in opposition to each other and their respective longitudinal fibers are disposed parallel to each other; adhering the respective opposing wide faces of the first group of strips to each other to form a face-bonded sheet; depositing an adhesive on the opposite narrow edges of a second group of the strips; arranging the second group of strips in a layer such that their narrow edges are disposed in opposition to each other and their respective longitudinal fibers are disposed parallel to each other; adhering the respective opposing narrow edges of the strips of the second group of strips to each other to form an edge-bonded sheet; and, laminating the face-bonded sheet between two edge-bonded sheets to form an I-type panel.

11. The method of claim 10, wherein the respective longitudinal fibers of the bamboo strips of the face-bonded sheet are disposed parallel to the respective longitudinal fibers of the bamboo strips of the edge-bonded sheets.

12. The method of claim 10, wherein the respective longitudinal fibers of the bamboo strips of the face-bonded sheet are disposed perpendicular to the respective longitudinal fibers of the bamboo strips of the edge-bonded sheets.

13. The method of claim 10, further comprising laminating a plurality of the face-bonded and edge-bonded sheets together in an alternating order.

14. The method of claim 10, wherein each of the edge-bonded sheets comprises blue bamboo strips, each having an outer skin facing outward from the I-type panel.

15. The method of claim 1, wherein the corresponding pairs of complementary mortise and tenon joints on the components are square, trapezoidal, circular, elliptical, or arcuate trapezoids.

16. An article of furniture, comprising: a first component made of engineered bamboo and having a tenon formed thereon; a second component made of engineered bamboo and having a mortise complementary to the tenon of the first component formed therein; and, means for adhering the tenon of the first component in the mortise of the second component.

17. The article of claim 16, wherein at least one of the first and second components comprises: a plurality of flat, elongated strips of bamboo, each having a pair of opposite wide faces, the strips being arranged in a layer such that their respective wide faces are disposed in opposition to each other and respective longitudinal fibers of the strips are disposed parallel to each other; and, an adhesive disposed on the opposite wide faces of the strips and adhering the respective opposing wide faces of the strips to each other to form a face-bonded sheet.

18. The article of claim 16, wherein at least one of the first and second components comprises: a plurality of flat, elongated strips of bamboo, each having a pair of opposite narrow edges, the strips being arranged in a layer such that their respective narrow edges are disposed in opposition to each other and respective longitudinal fibers of the strips are disposed parallel to each other; and, an adhesive disposed on the opposite narrow edges of the strips and adhering the opposing narrow edges of the strips to each other to form an edge-bonded sheet.

19. The article of claim 16, wherein at least one of the first and second components comprises: a first plurality of flat, elongated bamboo strips, each having longitudinal fibers and a pair of opposite wide faces and arranged in a layer such that their respective wide faces are disposed in opposition to each other and their respective longitudinal fibers are disposed parallel to each other; an adhesive disposed on the opposite wide faces of the first plurality of strips and adhering the respective opposing wide faces of the strips to each other to form a face-bonded sheet; a second plurality of flat, elongated bamboo strips, each having longitudinal fibers and a pair of opposite narrow edges and being arranged in a layer such that their respective narrow edges are disposed in opposition to each other and their respective longitudinal fibers are disposed parallel to each other; an adhesive disposed on the opposite narrow edges of the second plurality of strips and adhering the opposing narrow edges of the strips to each other to form an edge-bonded sheet; and, an adhesive laminating the face-bonded sheet to the edge-bonded sheet.

20. The article of claim 19, wherein at least one of the first and second components comprises a plurality of the face-bonded sheets laminated to a plurality of the edge-bonded sheets in an alternating order.

Bamboo Furniture Patent Ideas Description

RELATED APPLICATIONS

[0001] This application is a continuation of International App. No. PCT/CN2005/000390, filed Mar. 28, 2005, and having a priority date of Jan. 20, 2005, the entire disclosure of which is incorporated herein by reference.

BACKGROUND

[0002] 1. Technical Field

[0003] The present invention relates to furniture making, and in particular, to making engineered bamboo furniture joined with mortise and tenon joints.

[0004] 2. Related Art

[0005] At present, there is a scarcity of timber resources in the world, and the immoderate cutting of trees in previous decades has resulted in an ecological imbalance in the world's forests. Trees are not only expensive to plant, but also require a relatively long time (about 15-50 years) to mature into a size useful for lumber. By contrast, China and other Asian countries have an abundance of bamboo resources. Bamboo is relatively easy and inexpensive to cultivate and takes only a relatively short time (about 5-8 years) to mature to a useful size. Using bamboo instead of conventional wood timber to manufacture furniture can thus reduce the cost of furniture, make full use of the bamboo resource, protect the environment and thereby benefit mankind.

[0006] The mortise-and-tenon ("M&T") method of timber joining has been used in the Chinese culture since ancient times, and thus, the application of the M&T connection structure to bamboo furniture serves to preserve and carry forward an aspect of Chinese culture. "Engineered bamboo" (i.e., manmade bamboo timber, lumber, boards and plywood) is a relatively new material, and to date, has been used only to manufacture bamboo flooring and engineered bamboo panel furniture joined with conventional metal fasteners, e.g., screws. However, there is no record of implementation of M&T connection structures in the manufacture of engineered bamboo furniture.

SUMMARY OF THE INVENTION

[0007] In accordance with the present invention, a new, efficient and environmentally friendly material is provided, viz., engineered bamboo (including bamboo lumber and plywood sheets) that is useful for the manufacture of strong, decorative, high quality furniture in which the parts and components of the furniture are connected with mortise and tenon ("M&T") joints, without the use of any conventional wood products or joining techniques.

[0008] An exemplary method by which the engineered bamboo furniture with M&T joints described in the present invention is manufactured comprises manufacturing component parts of the furniture out of engineered bamboo; forming mortises and tenons of various types and shapes on or in the component parts, and bonding the component parts into a finished article of furniture using the mortises and tenons and an adhesive. The finished furniture may comprise a table, a chair, a cabinet, a bed, a book shelf or the like.

[0009] In the method of the present invention, the engineered bamboo material is made by laminating long flat strips of bamboo together with an adhesive under a relatively high pressure. Prior to their lamination, the bamboo strips are treated by heat-digesting, drying at a high temperature, carbonizing, dehydrating and a starch-extraction process. In one possible "face-bonded" embodiment, the processed bamboo strips are then laminated to each other by depositing an adhesive on opposite wide faces of the strips, arranging the strips in a layer with their wide faces in opposition with each other, and pressing them together in a press until the adhesive cures. In this procedure, "blue bamboo" strips, i.e., strips taken from the outer peripheral layer of the bamboo stalk, or "culm," are laminated alternately with "yellow bamboo" strips, i.e., those taken from the middle or inner wall layers of the bamboo culm, with their respective longitudinal cellulose fibers arranged parallel to each other, to form thin panel structures.

[0010] In another, "edge-bonded" embodiment, the opposite narrow edges of the treated bamboo strips are laminated to each other to form thin, single-ply sheets, and a plurality of the sheets are then laminated on top of each other to form plywood-like panels. In one variation of this embodiment, three of the edge-bonded sheets are laminated to each other with their respective longitudinal fibers all extending in the same direction, and with the hard, tough outer skin of blue bamboo strips forming the upper and the lower surfaces of the resulting bamboo panel. In a second variation of this embodiment, the upper and lower sheets of blue bamboo strips are disposed with their longitudinal fibers extending in one direction, and the middle sheet is arranged with the longitudinal fibers of its bamboo strips disposed perpendicular to those of the upper and the lower sheets.

[0011] Yet another possible embodiment of the engineered bamboo material comprises an "I-type" lamination, in which three or more layers are laminated together to form a plywood-like panel. The basic form of this embodiment comprises three layers, viz., a face-bonded middle layer, as above, sandwiched between upper and lower edge-bonded layers, as above. In a "multi-I" extension of this method and material, panels of almost any thickness desired are produced by laminating together additional layers in the foregoing alternating arrangement. As above, the longitudinal fibers of the respective alternating edge-bonded and face-bonded layers can be arranged either parallel or perpendicular to one another to achieve different material strength and stiffness properties, and the uppermost and lowermost edge-bonded layers can comprise blue bamboo strips with their hard, dense outer skins facing outward.

[0012] In general, the face-bonding and edge-bonding techniques are used to form thin board-like materials, the I-type technique is used to form medium thickness boards and small rectangular panels, and the multi-I method is used to form thick boards and large rectangular panels.

[0013] In accordance with the present invention, the tenons and complementary mortises used to join the furniture components can be square, trapezoidal, circular, elliptical, or arcuate trapezoids, and with suitable modification to accommodate the unique properties of engineered bamboo, many conventional mortise and tenon joints can be used for that purpose.

[0014] The following are among the many advantages attendant to the methods and materials of the present invention:

[0015] 1. The engineered bamboo material has superior physical mechanics performance and technical properties over conventional wood timber. It has a high density (.gtoreq.0.79 g/cm.sup.3), bending strength (90 MPa), and rigidity (60 MPa, up to 32 HB, whereas, Zelkova timber is 23 HB and Oak timber is only 24 HB). It also has excellent shock resistance (.gtoreq.95 kj/m.sup.2), and a higher compression strength than either Zelkova or Oak timber.

[0016] 2. In addition to the above advantages over conventional timber, engineered bamboo also has other outstanding performance advantages, e.g., a lower wet expansion ratio and a lower drying shrinkage (.ltoreq.0.5%), which enable the design and manufacture of furniture that breaks with the ordinary limitations imposed by the deformations experienced by conventional timber as a result of wet expansion.

[0017] 3. With suitable modifications, most conventional timber M&T connection techniques can also be used with engineered bamboo assemblies.

[0018] 4. By improving on the size and fit tolerances of conventional M&T connection techniques, engineered bamboo enables the fabrication of furniture with high accuracy and large, attractive surfaces having a good, smooth finish.

[0019] 5. Circular or ring-shaped parts or components can be formed simply by bending the bamboo board under either hot or cold pressure, rather than by cutting the lumber into segments and then reassembling them into the desired configuration, which is the method commonly utilized in manufacturing conventional timber furniture. This improvement results in a substantial saving of scrap material.

[0020] 6. Due to the high density, rigidity and excellent bending and compression strength of engineered bamboo, furniture having the same mechanical properties as larger, thicker conventional wood furniture can be made from thinner but stronger engineered bamboo materials. In this way, natural resources are conserved.

[0021] 7. Furniture made from bamboo evokes a clean, fresh, cool feeling during the summer-time.

[0022] 8. The length, width and thickness of the engineered bamboo boards and panels can be determined by the size of the furniture to be made from it. Thus the utilization efficiency of the material can be greatly improved, so that this renewable natural resource is fully utilized.

[0023] A better understanding of the above and many other features and advantages of the apparatus of the present invention and the methods of its use may be obtained from a consideration of the detailed description of the exemplary embodiments thereof below, particularly if such consideration is made in conjunction with the appended drawings, wherein like reference numerals are used to identify like elements illustrated in one or more of the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1A is an upper front end perspective view of an exemplary embodiment of a rectangular engineered bamboo panel having face-bonded bamboo strips in accordance with the present invention;

[0025] FIG. 1B is an enlarged detail view of the encircled portion of the panel of FIG. 1A;

[0026] FIG. 2A is an upper front end perspective view of an exemplary first embodiment of a rectangular engineered bamboo panel having three laminated sheets of edge-bonded bamboo strips, in which the elongated fibers of the respective strips of adjacent sheets are disposed parallel to each other;

[0027] FIG. 2B is an enlarged detail view of the encircled portion of the panel of FIG. 2A;

[0028] FIG. 2C is an upper front end perspective view of a exemplary second embodiment of a rectangular engineered bamboo panel having three laminated sheets of edge-bonded bamboo strips, in which the elongated fibers of the respective strips of adjacent sheets are disposed perpendicular to each other;

[0029] FIG. 2D is an enlarged detail view of the encircled portion of the panel of FIG. 2C;

[0030] FIG. 3A is an upper front end perspective view of an exemplary first embodiment of an "I-type" engineered bamboo panel having three laminated sheets comprising a middle sheet with face-bonded bamboo strips sandwiched between upper and lower sheets with edge-bonded bamboo strips, in which the elongated fibers of the respective strips of adjacent sheets are disposed parallel to each other;

[0031] FIG. 3B is an enlarged detail view of the encircled portion of the panel of FIG. 3A;

[0032] FIG. 3C is an upper front end perspective view of an exemplary second embodiment of an I-type engineered bamboo panel having three laminated sheets comprising a middle sheet with face-bonded bamboo strips sandwiched between upper and lower sheets with edge-bonded bamboo strips, in which the elongated fibers of the respective strips of adjacent sheets are disposed perpendicular to each other;

[0033] FIG. 3D is an enlarged detail view of the encircled portion of the panel of FIG. 3C;

[0034] FIG. 4A is an upper front end perspective view of an exemplary first embodiment of a "multi-I" type of engineered bamboo panel having a plurality of laminated sheets comprising sheets with face-bonded bamboo strips alternating with sheets having edge-bonded bamboo strips, in which the elongated fibers of the respective strips of alternating sheets are disposed parallel to each other;

[0035] FIG. 4B is an enlarged detail view of the encircled portion of the panel of FIG. 4A;

[0036] FIG. 4C is an upper front end perspective view of an exemplary second embodiment of a multi-I type of engineered bamboo panel having a plurality of laminated sheets comprising sheets with face-bonded bamboo strips alternating with sheets having edge-bonded bamboo strips, in which the elongated fibers of the respective strips of alternating sheets are disposed perpendicular to each other;

[0037] FIG. 4D is an enlarged detail view of the encircled portion of the panel of FIG. 4C;

[0038] FIGS. 5A and 5B are upper corner perspective views of a prior art three-dimensional mortise and tenon corner joint for conventional wood furniture, showing the joint in a disassembled and an assembled state, respectively;

[0039] FIGS. 5C and 5D are upper corner perspective views of an exemplary embodiment of a three-dimensional mortise and tenon dowelled corner joint for engineered bamboo furniture in accordance with the present invention, showing the joint in a disassembled and an assembled state, respectively;

[0040] FIGS. 6A and 6B are upper side perspective views of a prior art two-dimensional mortise and tenon corner joint for conventional wood furniture, showing the joint in a disassembled and an assembled state, respectively;

[0041] FIGS. 6C and 6D are upper side perspective views of an exemplary embodiment of a two-dimensional mortise and tenon corner joint for engineered bamboo furniture in accordance with the present invention, showing the joint in a disassembled and an assembled state, respectively;

[0042] FIG. 7A is an upper corner perspective view of a prior art dovetail joint for conventional wood furniture, showing the joint in a disassembled state;

[0043] FIG. 7B is an upper corner perspective view of an exemplary embodiment of a dovetail corner joint for engineered bamboo furniture in accordance with the present invention, showing the joint in a disassembled state;

[0044] FIG. 8A is an upper corner perspective view of an exemplary embodiment of a three-dimensional mortise and tenon corner joint for engineered bamboo furniture in accordance with the present invention, showing the joint in a disassembled state and intersecting mortise grooves located in the respective side rails of the corner;

[0045] FIG. 8B is an upper corner perspective view of another exemplary embodiment of a dove-tail corner joint for engineered bamboo furniture in accordance with the present invention, showing the joint in a disassembled state;

[0046] FIG. 8C is an upper side perspective view of an exemplary embodiment of a "horse mouth," or cross lap joint for engineered bamboo furniture in accordance with the present invention, showing the joint in a disassembled state;

[0047] FIGS. 9A and 9B are upper corner perspective view of another exemplary embodiment of a dovetail corner joint for engineered bamboo furniture in accordance with the present invention, showing the joint in an assembled and a disassembled state, respectively;

[0048] FIGS. 10A and 10B are upper side perspective views of an exemplary embodiment of a blind, or closed, T-type mortise and tenon joint for engineered bamboo furniture in accordance with the present invention, showing the joint in a disassembled and an assembled state, respectively;

[0049] FIGS. 11A and 11B are upper corner perspective views of an exemplary embodiment of a rectangular furniture panel assembly made of engineered bamboo components joined together with a variety of mortise and tenon joint types in accordance with the present invention, showing the panel in an assembled and a partially disassembled state, respectively;

[0050] FIGS. 12A and 12B are upper corner perspective views of an exemplary embodiment of a three-dimensional dowelled mortise and tenon corner joint for engineered bamboo furniture in accordance with the present invention, showing the joint in a disassembled and an assembled state, respectively;

[0051] FIG. 13 is an upper side perspective view of an exemplary embodiment of a lattice-top table made of engineered bamboo components joined together with a variety of mortise and tenon joint types in accordance with the present invention, showing the table in a disassembled state and the table top in an assembled and a partially disassembled state; and,

[0052] FIG. 14 is an upper left front perspective view of an exemplary embodiment of a bed frame made of engineered bamboo components joined together with a variety of mortise and tenon joint types in accordance with the present invention, showing the bed in a partially disassembled state.

DETAILED DESCRIPTION

[0053] As described below in conjunction with the accompanying drawings, the present invention provides methods for making high quality engineered bamboo furniture in which the components are joined together with mortise and tenon ("M&T") joints. Preparation for implementing the methods of the present invention includes following steps:

[0054] 1. Measuring the mechanical and physical properties (including compression strength, bending strength, flexural modulus, impact hardness, shear strength, rigidity, bending resistance, wear rate, nail holding power, and the like) of the engineered bamboo materials (i.e., the bamboo boards and plywood) to be utilized in the furniture.

[0055] 2. Determining the desired structural and material (i.e., face-bonded, edge-bonded, or combinations thereof) properties of the furniture components, based on the above mechanical and physical properties of the engineered bamboo materials, and determining the dimensions of the material components necessary to achieve those properties.

[0056] 3. Determining the optimum M&T joining techniques to be used to join the components of the furniture together, including definition of corresponding product quality standard procedures, processing equipment, cutting tool, die clamp requirements and the like.

[0057] The engineered bamboo furniture with M&T joints of the present invention makes use of a manmade, "engineered bamboo" material that is made of elongated, flat bamboo strips having opposite wide faces and opposite narrow edges that are laminated together with an adhesive under high pressure. Prior to their lamination, the bamboo strips are treated by high temperature steaming, high temperature drying, carbonizing, dehydrating and a process that extracts the starch from them. The bamboo strips are cut axially from the bamboo stalk, or "culm," and comprise two types, viz., "blue bamboo" strips, i.e., those taken from the outer peripheral wall layer of the culm, which have a relatively tough, dense, outer skin, and in which the long, axial, cellulose "veins," or fibers are more dense, and "yellow bamboo" strips, i.e., those taken from the middle and inner wall layers of the bamboo culm, in which the axial fibers are less dense.

[0058] As illustrated in FIGS. 1A and 1B, in one possible "face-bonded" embodiment, bamboo strips 10 processed as above are laminated to each other by depositing an adhesive on the wide faces of the strips, disposing the strips in a planar layer with their respective wide faces in opposition to each other, and then pressing them together in a press until the adhesive cures. In this process, blue bamboo strips are laminated alternately with yellow bamboo strips, with their respective longitudinal cellulose fibers arranged parallel to each other, to form a thin panel-like structure 12.

[0059] FIGS. 2A-2D illustrate another possible embodiment, viz., an "edge-bonded" embodiment, in which the respective opposite narrow edges of the treated bamboo strips 20 are first laminated to each other, as above, to form thin, single-ply sheets 22, and wherein the sheets are then laminated on top of each other to form plywood-like panels 24. In the variation of this embodiment illustrated in FIGS. 2A and 2B, three of the edge-bonded sheets are laminated to each other with the longitudinal fibers of their respective bamboo strips all extending in the same direction, and preferably, with blue bamboo strips forming the upper and the lower surfaces 26 and 28 of the resulting panel, such that the hard, dense outer skin faces outward. As illustrated in FIGS. 2C and 2D, in a second possible variation of this embodiment, the upper and lower sheets of blue bamboo strips are disposed with their longitudinal fibers extending in one direction, and the middle sheet is arranged with the longitudinal fibers of its bamboo strips disposed perpendicular to those of the upper and the lower sheets.

[0060] FIGS. 3A-3D illustrate yet another possible embodiment of the engineered bamboo material of the present invention, comprising an "I-type" lamination, in which three or more layers are laminated together to form a plywood-like structural panel 30. The basic form of this embodiment consists of three layers, viz., a face-bonded middle layer 32, of the type described above, which is sandwiched between upper and lower edge-bonded layers 34 and 36, as described above. As in the above embodiments, the longitudinal fibers of the respective strips of the alternating face-bonded layer 32 and the edge-bonded layers 34 and can be arranged either parallel to each other, as illustrated in FIGS. 3A and 3B, or perpendicular to each another, as illustrated in FIGS. 3C and 3D, to achieve different panel strength and stiffness properties. In a preferred embodiment, the strips forming the upper and the lower layers 34 and 36 comprise of blue bamboo strips with their respective dense outer skins facing outward.

[0061] A "multi-I" extension of the embodiment of FIGS. 3A-3D is illustrated in FIGS. 4A-4D, which illustrate that panels 40 of almost any thickness desired can be produced by laminating together additional face- and edge-bonded layers 42 and 44 in the alternating arrangement described above. And, as in the above I-type embodiment above, the longitudinal fibers of the respective bamboo strips of the alternating edge-bonded and face-bonded layers can be arranged either parallel or perpendicular to one another to achieve different material strength and stiffness properties.

[0062] As will be evident from the foregoing description, it is possible to form a wide variety of engineered bamboo material types, including boards, lumber and structural panels, that are useful for making furniture. Generally speaking, the face-bonding and edge-bonding techniques are useful to make thin, board-like materials, the I-type technique is useful to make medium thickness boards and small rectangular panels, and the multi-I method is useful to make thick boards and large rectangular panels.

[0063] In accordance with the present invention, the components of the furniture made from the engineered bamboo materials described above (i.e., engineered bamboo boards and panels) are preferably joined together with M&T joints, by the following method: Forming tenons and corresponding mortises (or grooves) of different shapes on or in the engineered bamboo parts; coating the tenon and/or corresponding mortise with an adhesive and inserting the tenon into the corresponding mortise; curing the adhesive; and, finishing the assembled parts. The M&T joining step may include forming butt joints, lap joints, tongue-and-groove joints, dado joints, dowelled joints and dove-tailed joints. The M&T joints utilized may include both open, or through joints, blind or closed joints, and joints that are mitered.

[0064] The timber normally used for making furniture comprises a woody, fibrovascular tissue that comes from the trunks of perennial coniferous or broadleaf trees. The diameter of the trunks of such trees depends on the age of the tree. Their wood tends to be elastic, high in wet expansion ratio and drying shrinkage, and is therefore relatively easy to process. Accordingly, conventional wood structures, including furniture, can utilize mortise and tenon joints of many types. However, engineered bamboo has a relatively higher rigidity and strength, and relatively lower wet expansion and drying shrinkage ratios. Accordingly, it is necessary to modify most conventional timber mortise and tenon joints and to implement new M&T joint designs for use with engineered bamboo materials.

[0065] FIGS. 5A and B, 6A and B, and 7A and B respectively illustrate a conventional three-dimensional M&T corner connection structure, a conventional two-dimensional M&T corner connection structure, and a conventional M&T, "dove-tail" corner connection, commonly used in the construction of conventional wood furniture.

[0066] FIGS. 5C and 5D illustrate a modification of the conventional three dimensional corner joint illustrated in FIGS. 5A and 5B that is useful with engineered bamboo furniture, and which comprises a plurality of cylindrical, dowel-like tenons 52 and corresponding complementary cylindrical mortises (not seen in FIG. 5C) formed on and in the respective parts. As may be seen from a comparison of the two sets of figures, the use of engineered bamboo enables simplification of the M&T joint structure, eliminates some of the manual operations involved in making and assembling a conventional three dimensional M&T joint, and is therefore easier to implement, more reliable and precise, and hence, better adapted to large scale automated furniture manufacture.

[0067] FIGS. 6C and 6D illustrate an advantageous modification of the conventional two dimensional wood corner joint of FIGS. 6A and 6B that is useful with engineered bamboo furniture. As may be seen by a comparison of the two sets of figures, the joint 60 modified for use with engineered bamboo is simpler, and hence, facilitates the joint formation process. The modified M&T structure of FIGS. 6C and 6D can be formed in one processing step (whereas, the conventional timber M&T joint of FIGS. 6A and 6B needs three), results in parts having good interchangeability, and hence, is better adapted to large scale automated furniture manufacture.

[0068] FIG. 7B illustrates a modification of the conventional timber dovetail M&T joint of FIG. 7A to better adapt it for use with engineered bamboo materials. Because engineered bamboo is harder, stiffer and more brittle, dove tail joints preferably should not incorporate relatively sharp 90.degree. angles and corners 72, of the type seen in FIG. 7A. Instead, as shown in FIG. 7B, the outer side surfaces of the tenons and the complementary interior wall surface of the corresponding mortises are preferably processed to incorporate an arcuate form 74. The modified arc form decreases the compressive stress imposed on the parts during assembly, and can be formed in one processing step with high precision, and hence, is well adapted to large scale automated furniture manufacture.

[0069] FIGS. 8A and 8B respectively illustrate two M&T joint structures 82 and 84, similar to those respectively illustrated in FIGS. 6C and 7B, that are useful with the engineered bamboo furniture of the present invention. These two joints are optimally adapted to take advantage of the engineered bamboo properties of high rigidity and hardness, lower expansion and shrinkage ratios, and small deformation. They make good use of modern glue-bonding techniques and new engineered bamboo plate and frame structures that facilitate and prompt assembly, and thus, simplify construction.

[0070] FIG. 8C illustrates a novel "horse mouth," or cross lap M&T joint 86. This structure is formed by milling spaced mortises, or grooves 88, in a plurality of engineered bamboo boards, sawing the boards to the desired lengths, and assembling the boards together as desired. This form of M&T joint is well adapted to making open lattice, or "egg crate" structures, acts to prompt the assembly process, and guarantees good precision, and hence, is also well adapted to large scale automated furniture manufacture.

[0071] FIGS. 9-14 illustrate various types of M&T joints that are well adapted for the joining of furniture components made of engineered bamboo. FIGS. 9A and 9B respectively illustrate an open, or visible, dovetail corner joint 90 for engineered bamboo components. As shown in FIG. 9B, arcuate trapezium dovetail tenons 92 are machined at one end of a first bamboo board 94, and corresponding complementary mortises 96 are machined at an end of a second bamboo board 98. The tenons 92 are coated with an adhesive, then pressed into the corresponding mortises 96 of the bamboo board 98, and the two boards are then clamped at a 90.degree. angle while the adhesive cures. After the adhesive is cured, the two boards are permanently joined together at a right angle through the resulting M&T corner joint 90.

[0072] FIGS. 10A and 10B illustrate a blind, or closed, "T-type" M&T joint 100 useful with square engineered bamboo components. As shown in the figures, a square tenon 102 is machined at one end of a square bamboo component 104, and a complementary square mortise 106 is machined into a second square bamboo component 108. The square tenon 102 is coated with an adhesive and then inserted into the complementary mortise 106, by which the two parts are permanently joined together in a T-shaped M&T joint.

[0073] FIGS. 11A and 11B illustrate a rectangular furniture panel assembly 110 made of engineered bamboo components joined together with a variety of mortise and tenon joint types in accordance with the present invention. Such panel assemblies are useful for making a variety of furniture articles, including chests, sideboards and the like. As shown in the figures, when such a flat panel assembly is to be assembled, tenons 112 formed at opposite ends of elongated frame pieces 114 are inserted into corresponding mortises 116 formed at opposite ends of other frame pieces 118 to define a rectangular frame. The marginal edges 120 of a rectangular engineered bamboo panel 122 of the type described above are inserted into corresponding grooves 124 formed in the frame pieces, and additional tenons 126 disposed around the periphery of the panel are inserted into corresponding mortises 128 in the side pieces of the frame, by which the assembly of the flat panel assembly is complete.

[0074] FIGS. 12A and 12B illustrate a three dimensional (i.e., extending in three orthogonal directions) M&T corner joint 120 adapted for use with square engineered bamboo components, which is similar to that described above in connection with FIGS. 5C and 5D. Cylindrical dowel-like tenons 122 are machined at one end of two of the three square bamboos components, and then inserted into respective corresponding complementary cylindrical mortises 124 formed into two of the three components, by which an invisible M&T corner joint of the three components is effected in three orthogonal directions, as shown in FIG. 12B.

[0075] FIG. 13 illustrates an exemplary process for making a lattice-top table made of engineered bamboo components joined together with a variety of M&T joint types in accordance with the present invention. As illustrated in the figure, some of the components are first assembled into subassemblies, such as the two leg subassemblies 132 and the table top subassembly 134 shown, and the subassemblies are then joined together to form the completed table, in the following manner:

[0076] Firstly, square tenons 136 and corresponding square mortises 138 are formed at opposite, mitered ends of pair of horizontal foot rails 140 and two pairs of upright leg rails 142, and each of the foot rails is joined to an associated pair of the leg rails to form a pair of leg subassemblies 132.

[0077] Secondly, the table top subassembly 134 is formed by joining the mitered ends of four elongated side rails 144 and 146 to each other to define a rectangular frame, as described above in connection with FIGS. 11A and 11B, and the inside periphery of the frame is then joined to the lateral periphery of an "egg crate" or lattice-type table top panel 148, which can be constructed using the cross lap M&T joint described above in connection with FIG. 8C. In an alternate embodiment (not illustrated), the table top can comprise a solid engineered bamboo panel assembly such as the one described above in connection with FIGS. 11A and 11B.

[0078] Lastly, the two leg subassemblies 132 are joined to the table top subassembly 134 with the corresponding M&T joint pairs 136 and 138 on the two subassemblies, by which the table is complete, except for surface finishing procedures.

[0079] FIG. 14 illustrates an exemplary process for making a bed frame 140 of engineered bamboo components joined together with a variety of M&T joint types in accordance with the present invention. As in the previous example, some of the bed components are first assembled into subassemblies, and the subassemblies are then assembled into the completed bed frame.

[0080] In the exemplary embodiment of FIG. 14, the bed frame 140 is assembled by the following procedure: Assembling a headboard subassembly 142 and a footboard subassembly 144, each using M&T joints; providing a pair of side rails 146, each having a pair of metal latch pins 148 extending outward from opposite ends thereof; inserting the metal latch pins of the side rails into corresponding metal hook apertures 150 contained in opposite sides of each of the headboard and footboard subassemblies to form a rectangular bed frame. If desired, a rectangular engineered bamboo mattress support panel (not illustrated) can be provided that has opposite side edges that are supported on corresponding interior ledges 152 formed on the side rails, and optionally the support panel can include dovetail tenons that engage and interlock with corresponding mortises 154 formed in the side rail ledges.

[0081] It may be noted in the above exemplary embodiment that conventional metal hook-and-latch pins 148 and 150 are used to connect the side rails 146 to the headboard 142 and footboard 144 of the bed frame 140. Metal couplings are preferred in this particular application because bed frames must occasionally be disassembled for moving, storage or the like, and accordingly, a permanent adhesive joint is contraindicated.

[0082] By now, those of skill in this art will appreciate that many modifications, substitutions and variations can be made in and to the materials, apparatus, configurations and methods of the present invention without departing from its spirit and scope. Accordingly, the scope of the present invention should not be limited to that of the particular embodiments illustrated and described herein, as they are merely exemplary in nature, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.
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