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1. Field of the Invention
The present invention relates to a method for manufacturing decorative hollow tubing and more particularly to decorative hollow tubing used for manufacturing furniture.
2. Description of the Related Art
Furniture is often constructed from decorative cylindrical structures. For example, bamboo and other grasses and woody plants have long been utilized to fabricate furniture and other articles. The appearance of such furniture and other articles is so pleasing as to have inspired many attempts to simulate bamboo and the like when rendered artificially from materials other than those of natural plants. Table legs are often formed in shapes which are cylindrical in nature and which may include shapes of various radii extending from the longitudinal axis of the table leg.
One of the unsolved needs of the furniture and other industries wherein it is desirable to provide decorative cylindrical tubing, such as simulated bamboo stalks in a realistic rendition of nodes and culms which characterize natural bamboo, while fabricating the decorative cylindrical tubing from inexpensive yet strong and durable tubular stock material. Many prior art attempts to manufacture such decorative tubing such as simulated bamboo depend upon inscribing nodes into tubing or, alternatively, deforming the stock material such that simulated nodes project outwardly from the tubing. Both approaches fail to achieve realistic effect.
Casting can realistically provide decorative cylindrical structures but cast construction, particularly from metals, has undesirable attributes. One is that resultant cylindrical structures are relatively heavy, being solid rather than hollow, compared to worked tubing. Although hollow castings can be produced, this greatly increases difficulty and expenses of manufacture. Another is that the cost of fabricating suitable dies providing the desired ornamentation is extremely expensive. A further problem is that cast metallic structures are usually brittle and unsuitable for fabricating furniture, which represents a broad use of such hollow decorative cylindrical structures. Brittleness leads to ready breakage and also prevents imparting mild curvature during fabrication to straight sections of decorative cylindrical structures. Although the product could be cast in the final desired configuration, this will likely increase the number of expensive dies required to fabricate a set of related articles of furniture. Still another problem with casting is that cast construction is difficult at best to weld, which may be required when fabricating assembled products such as furniture, in which sections of decorative cylindrical structures intersect.
The present invention describes a method for manufacturing decorative cylindrical tubing which exhibits a desired external ornamental configuration from thin walled metallic or plastic tubing. This construction provides a number of features. One feature of the invention is the ability to provide strength and durability of construction from metals or plastics. Another feature is the ability to utilize metallic material in stock form, such as extruded or rolled and welded stock.
An additional aspect is to avoid casting as a fabrication technique, thereby avoiding inherent disadvantages of casting such as expense and brittleness of the product. A further aspect of the present invention is that it achieves a realistic appearance of natural bamboo stalks or other desired ornamentation. Still another aspect is to provide a constituent material which simulates bamboo or other desired ornamentation while having the strength requisite for fabricating furniture while limiting the overall diameter of the decorative cylindrical tubing. A further aspect is that the decorative cylindrical tubing may be bent slightly to achieve desired contours without failing, displaying visible distortion such as wrinkling and cracking, or significantly weakening. A still further aspect is to be able to weld abutting sections of decorative cylindrical tubing.
The invention provides these qualities while realistically simulating bamboo or other desired ornamentation. To this end, the present invention contemplates fabricating decorative cylindrical tubing, utilizing thin walled tubing as a stock material and cold working the stock material to exhibit a desired ornamentation such as simulated nodes and simulated tapering of culms typical of natural bamboo. The invention may take the form of a stock material simulating bamboo or, alternatively, of any desired cylindrical shape and ornamentation.
Accordingly, the invention provides decorative cylindrical tubing in the form of thin walled metallic tube stock configured to simulate bamboo or other desired ornamentation. The invention also simulates characteristics of natural bamboo such as nodes and curvature of culms. Finally, the invention provides improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. These and other aspects of the present invention will become readily apparent upon further review of the following specification and drawings.
Various other aspects and features of the present invention will become more fully appreciated as the same become better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views and wherein:
For illustrative purposes,
Where a series of abutting sections are provided, they may be fabricated from a single piece of tubing of desired length. Sections of culms of natural bamboo are characterized in that each has enlarged nodes separating adjacent sections, and in that each section is progressively, increasingly tapered from the minimum diameter of the section, usually at the middle, towards the maximum diameter located near each node. Both this characteristic taper and also joint structure of each node, which joint structure includes a defined crease where abutting sections meet, are reproduced in the present invention, using tubular stock material as a raw material. This was heretofore an unrealized goal in commercial production of simulated bamboo products.
The tubular stock material is both sufficiently malleable as to accept cold working to reproduce realistic node and culm characteristics, and also sufficiently rigid to provide structural members for furniture. Examples of preferred stock tubular material include rolled ferrous metallic stock, such as steel, and extruded aluminum material. Aluminum material will be understood to encompass aluminum and its alloys. However, other malleable, strong materials such as other metals and alloys, polyvinyl chloride, and other plastics could be utilized if desired.
The simulated section 12 is tapered to simulate the taper of a culm of natural bamboo. To this end, the simulated section 12 has a portion of a first node 14 at the proximal end 16 of the simulated section 12 and a portion of a second node 17 at the distal end 18 of the simulated section 12. As seen in
Minimum and maximum outer diameters of other sections may be identical to those of the simulated section 12, although this represents a departure from natural bamboo. In natural bamboo, maximum and minimum outer diameters of each section generally become progressively smaller from the base of the stalk to the tip of the stalk. For purposes of fabricating articles from simulated bamboo, lengths of simulated bamboo are used wherein such decrease in dimensions is not discernible to casual observation. Similarly, the length of each one of a series of sections formed in a length of stock material according to the present invention may vary in a manner not found in nature.
The nature of the tapering of section 12 will now be described, with reference to
The slope described above characterizes the proximal end 16. The distal end 18 is essentially a mirror image of the proximal end 16, and thus need not be shown to the scale and level of detail of
The simulated nodes 14 and 17 are disposed between and separate the simulated section 12 and additional sections essentially similar to the simulated section 12. The simulated nodes 14 and 17 are formed at abutting tapered portions of the simulated section 12 and any adjacent section where each section has the greatest diameter. The simulated nodes 14 and 17 are each cold work depressed into the stock material 10 such that the interior surface 28 is inwardly displaced, as indicated for the simulated node 14 by an inward bulge 30 in
Referring now to
To provide aesthetic benefits of simulation of bamboo, the members 42, 44, 46, 48, 50, 52, and 62 are made from the stock material 10. An advantage of the nature of the stock material 10 is that lengths of the stock material 10 can tolerate some bending, as seen by examining the structural members 42 and 48, among others, and still maintain the characteristic curvature of each section of simulated bamboo. The effect of simulated bamboo can be combined with other thematically related visual features. For example, the seat 54 and the seatback 56 are formed from real or simulated wicker construction. Real or simulated rattan is another example of thematically related material. Also, simulated bamboo members may be combined in the frame structure with members that do not simulate bamboo.
It should be noted that the entire length of every structural member of the chair 40 need not be worked to simulate bamboo. For example, concealed portions of the structural members 46 and 48 may retain their original stock configuration. Such construction saves cost of producing the chair 40 while still presenting a dominant impression of bamboo construction. The concealed structural members 58, 60, 64, 66, 68, and 70 also need not be worked to simulate bamboo.
Both lengths of stock material corresponding to the stock material 10 and also articles utilizing the stock material in fabrication may utilize alternative embodiments of the invention wherein a length of the stock material 10 may include the novel characteristics set forth above in combination with other configurations. For example, lengths of the stock material 10 may be configured according to the invention along only part of the entire length thereof. The remaining length may be of the original cross sectional configuration or, alternatively, may be formed to have another configuration. The remaining length may be ornamented utilizing a different decorative scheme, or may be unornamented. In the example of the embodiment of
The simulated stock material 10 thus described is formed from cylindrical, annular tubing by cold working. It is thought that the best way of imparting the described characteristics to tubing is accomplished by using dies. The preferred method is to place a plurality of complementing dies around a tube 88, urge the dies inwardly such that they converge in complementing contact with the tube 88. This arrangement is shown diagrammatically in
The dies 80, 82, 84, and 86 are urged or forced inwardly towards the tube 88, as indicated by arrow in
A length of stock material 10 is formed by repeating the operation for forming nodes, with relative positions of the dies 80, 82, 84, and 86 and the tube 88 being adjusted to suit. The end clamps are then applied to the tube 88 to keep it stationary in a fixed position, restricted without any axial or rotational motion. It would be possible to fabricate dies (not shown), including more than one node, so that more than one section of simulated bamboo is formed in every forming operation. However, the apparatus and method described above will result in minimal capital outlay for dies, and also confer ability to form only one section on the tube 88. Also, this may be desirable in articles wherein only a short section of a structural member simulating bamboo is revealed.
Other methods may be employed to form the stock material 10. For example, dies (not shown) extending the full length of a tube which is to be reconfigured to simulate bamboo may be utilized. Where full length dies are utilized, tubing may be urged outwardly, such as by applying internal fluid pressure, an example being hydroforming. Alternatively, specially formed rollers may be employed in a die rolling method. Die forming, rolling, and other techniques may be combined if desired.
To achieve external surface designs other than bamboo, different dies would be employed. The dies are rendered as a negative of the ornamentation desired on the external surface of the decorative hollow tubing.
It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.
The present application is a continuation-in-part of U.S. application Ser. No. 11/728,765, filed on Mar. 27, 2007, which is a continuation-in-part of U.S. application Ser. No. 10/436,013, filed May 12, 2003, now abandoned, which claims the benefit of U.S. Provisional Application No. 60/379,103, filed May 10, 2002, the entire contents of all of which are incorporated herein by reference.
Number | Date | Country | |
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60379103 | May 2002 | US |
Number | Date | Country | |
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Parent | 11728765 | Mar 2007 | US |
Child | 12938830 | US | |
Parent | 10436013 | May 2003 | US |
Child | 11728765 | US |