a) Field of the Invention
The present invention relates, generally, to woodworking. More particularly, the invention relates to the method for making a pattern in wood. The invention has particular utility for decorative wood products.
b) Background Art
Wood with a distinctive surface appearance has long been valued for decorative applications, such as furniture, musical instruments, and art. The surface appearance of wood is a combination of the growth-ring structure or grain, the orientation of the surface that results from cutting, and particular anatomical features of the wood. The term “figure” is used to refer to distinctive markings on longitudinal or side grain surfaces of wood, generally when referring to more decorative woods. For example, there is curly maple, fiddleback mahogany, ribbon or strip figure, bird's-eye figure, blister figure, and quilted figure. When such wood is finished flat and smooth, a desirable visual effect is produced by variable light reflection intersecting the surface at various angles to the uneven or undulating cell structure in the wood. A thorough discussion of figure in wood can be found in “Understanding Wood” by Bruce Hoadley (published in 2000 by Taunton Press, ISBN 1-561158-358-8).
The state of the art includes various devices and methods for working the surface wood to create decorative patterns and shapes. Three-dimensional shapes and patterns are conventionally milled into the wood. Composite wood material is pressure-molded to achieve the desired pattern. The surface of such wood is purposefully left three-dimensional to achieve its desired decorative effect.
Also, it is known that in ferrous metals there is a technique called pattern welding “Damascus”, or in fine metals, such as gold and silver, it is called “Mokome Game”, and a similar technique in glass is referred to as “Cameo Glass”. These techniques rely on the layering of opaque contrasting materials, and then exposing these materials in such a way as to create a pleasing line or series on the material surface.
A search of the patent literature has developed several patents, these being the following:
U.S. Pat. No. 619,298 (Gochnaur) shows a “wood grainer” which comprises a tool having a flexible plate constructed of vulcanized rubber, and having on its outer surface a design which is impressed on the surface of the plate or cover under high pressure and temperature to form a pattern simulating the grain of a wood surface. In operation, the device is dragged over the surface that is being treated, and can be tilted at different angles to produce a different configuration.
U.S. Pat. No. 1,441,922 (Gstalder) discloses a “graining tool” which has a rubber surface having a pattern of ridges thereon.
U.S. Pat. No. 3,486,919 (Dreazy et al.) discloses a process of providing a grain pattern of ornamental wood to the surface of a panel, such as plywood or hardboard. The panel is first sanded and then coated with a sealer. The sealer coat is dried and then grooves are formed in the plank and are prime coated with a base pigmented paint. The panel is sanded with a 240E grit belt sander and a pigmented ground coat is applied to mask completely the natural color of the wood. The panel is next embossed to form a substantial portion of the pores that appear in natural wood that is to be simulated, with this being done by an embossing roller. Next, the panel is subjected to a series of painting steps. Then, the panel is subjected to a brush print of the general grain pattern of the planks of wood to be simulated. This provides a shadow background of the detailed ground pattern. After the printing step is completed, the embossed pores are filled with a dark filler material, followed by applying a clear top finish material.
U.S. Pat. No. 3,843,992 (Briggs) shows a wood-graining material having a surface of rubber or flexible plastic with a graining surface thereon. The layer of material is easily and readily snapped onto and off the curved surface of the tool.
U.S. Pat. No. 4,007,767 (Colledge) discloses a “high-speed rotary branding process,” for a wood surface. This comprises a die pattern thereon which is rolled over the material at a temperature of about 800° degrees to 900° degrees F. It is stated that operating at this temperature will provide the desired result, and also minimize the deterioration of the die pattern.
U.S. Pat. No. 5,507,064 (King) discloses a wood-graining tool which comprises a flexible panel positioned around a cylinder and a series of embossed ribs. The rib portions desirably extend in angular relationships of generally 40° degrees to 50° degrees relative to the edges of the tool.
The method of the present invention is able to form a pattern in the surface of a wood member so that there is an exposed substantially two-dimensional surface which gives the visual impression of a three-dimensional surface. This method takes advantage of the inherent reflective qualities of the individual wood cells in order to achieve a figured effect. Also, the wood article produced by the method of the present invention is able to reflect light in various ways so as to produce a three-dimensional visual effect.
In the method of the present invention, there is provided a wood member which has a wood surface and wood cells formed in the wood cell structure of the wood member. The wood member has a plurality of wood cell structure portions at higher and lower levels relative to the wood surface. The surface of the wood member is embossed to form a pattern of ridges and valleys at the wood surface. The resulting wood cell structure comprises ridge wood cell structure portions at higher and lower levels adjacent to the upper wood surface, and valley wood cell structure portions at higher and lower levels adjacent to the wood surface.
Also, there are transition wood cell structure portions which are located between adjacent wood and valley wood cell structure portions, and which are slanted and are higher and lower levels. The valley wood cell structure portions are displaced downwardly relative to the ridge wood cell structure portions. The transition wood cell structure portions are slanting downwardly from the adjacent ridge wood cell structure portions to adjacent valley wood cell structure portions.
After the embossing of the wood member, at least upper portions of the wood cell structure portions and upper portions of the transition wood cell structure portions are removed to form a modified exposed surface comprising exposed wood surface portions which comprise lower level ridge portions of the ridge wood cell structure portions and higher level valley portions of the valley wood cell structure portions. Also, there are the exposed wood surface portions of the transition wood cell structure portions that are located at a lower position in the wood member after embossing.
Thus, the modified exposed surface that is created has a contrasting surface pattern with a three-dimensional visual effect.
In a preferred form of the present invention, prior to embossing the wood member, the wood member is plasticized at at least upper wood cell structure portions to soften lignin therein. This can be accomplished by subjecting the wood member to heat, such as by placing the wood member in a steam chamber. Alternatively, the wood member can be plasticized by use of a chemical agent, and particularly exposing the wood member to anhydrous ammonia, or subjecting the wood member to pressurized ammonia gas.
The embossing can be accomplished by pressing a die against the wood surface. This die is able to be a heated die. Also, a flat die can be used or a roller die.
In the preferred form, the wood member is dried after embossing the wood member.
Also in the preferred form, the removing of at least upper portions of the ridge cell structure portions is accomplished in a manner to form the modified exposed wood surface as a planar surface. The transition wood cell structure portions are positioned at a slant relative to the modified exposed wood surface, and the maximum slant of the transition wood cell structure portions would be greater than zero degrees and not greater than about one-half of a right angle. A more preferred range is between angles of at least 3° degrees and 35° degrees, and in the more preferred range where the angle of slant is between 5° degrees and 15° degrees.
Also, the present invention comprises a decorative article of wood made in accordance with the processing steps of the present invention. Desirably, after the removal of the upper ridge cell structure portions to form a substantially flat surface, the surface is finished with a lacquer or protective coating which is permeable to light so as to provide reflections from the wood surface.
The article of wood made from the present invention is the result of performing the embossing of the wood member and also the removal of at least the upper portions of the wood cell structure portions. This article of wood is characterized in that the surface portions at ridge zones of the surface comprise lower level ridge portions of the ridge cell structure portions. Further, the surface portions at the valley zones comprise higher level valley portions of the valley wood cell structure portions.
The surface portions at the transition zones comprise portions of the transition wood cell structure portions that are positioned at lower locations in the wood member after embossing. Further, these portions of the transition wood cell structure have wood cell orientations which are aligned differently from wood cell orientations of the surface portions of the ridge zones and the valley zones. Thus, the light is reflected differently from the surface portions of the transition zones, than from the surface portions of the ridge and valley zones.
Other features of the present invention will be apparent from the following detailed description.
Referring to
The basic process is to provide a wood member 10 (a portion of which is shown in
This process can simulate desirable figure in wood that normally does not display any such figure. For example, a curly or bird's-eye pattern can be simulated in ordinary maple, or a fiddleback pattern simulated in ordinary mahogany. This process can also produce a figured effect in a variety of wood species that are not normally associated with exhibiting figure of their own, (for example, pine, alder, and poplar).
The process and its effect on the cell structure of wood is illustrated in
When the embossing die 24 is pressed into the upper wood portion 10, the cell structure of wood portion 10 is deformed so that the upper surface 11 of wood portion 10 conforms to the pattern of the embossing die as illustrated at 30 in
It is desirable that the cell structure be reoriented a substantial distance into the wood so that the pattern will be shown dramatically after the embossments are removed. To accomplish this, prior to embossing, the wood preferably undergoes a short-term “plasticization” process that increases the effectiveness of the embossing process by temporarily softening the lignin in the wood. Plasticization is not absolutely necessary to achieve a figured effect, but if not used, the final product will not be as stable and the figured effect will not penetrate as deeply into the wood.
Lignin is a chemical substance that comprises approximately twenty-five percent (25%) of the wood's substance; interspersed with cellulose it forms the cell wall. Lignin stiffens the cell wall and functions as a bonding agent between the cells. There are three principle methods to soften lignin, any of which can work in the present invention, and are as follows:
Embossing raises a surface design by depressing the surrounding material. With the wood temporarily plasticized, embossing significantly reorients the cell structure of the wood surface, and more importantly, it reorients the cell structure below the surface to a varying degree. The sub-surface effect of the embossing process diminishes with depth, typically to a depth below the valley surfaces about as great as the vertical distance between the level of the top surface of the peaks and the lower surface of the valleys. However, this depth could be 10%, 20%, 30%, 40% or 50% greater or smaller, depending on various factors.
The degree to which the cell structure can be reoriented depends on several factors: the type of the wood, the degree to which the wood has been softened, the die pattern depth, the thickness of the wood, and the amount of pressure and rate of speed with which the die is applied. Care should be taken not to exceed the plastic limit of the softened wood. To exceed this limit results in hairline cracking and tearing of the wood fibers in the areas of tension within the pattern.
There are two well-known embossing methods that can be used. The first method presses a flat die of the desired texture, design, or pattern into the plasticized wood surface. The second method rolls a textured or patterned roller over the wood surface. Each method must be applied with sufficient force to permanently deform the wood cell structure.
During the embossing process, the entire wood surface can be compressed to a varying degree. The result is a wood surface that is denser and hence harder, and more durable than the original wood surface. In one preferred embodiment of the present invention, the deformation of the cell structure can be to a depth as great as ⅛ inch. If the wood member is a sheet or piece of veneer having a total thickness dimension of about ¼ inch, the desired depth of the embossment (i.e., the vertical dimension from the peaks of the ridges to the floor of the valleys would be 1/16 inch and the underlying wood structure would be ⅛ inch, for a total of 3/16″ thickness from the uppermost part of the peaks to the bottom surface of the wood member 10 (assuming there has been 1/16 inch total comparison). Obviously, these dimensions could be changed. The total thickness of the wood piece could be that of a wood panel, such as a nominal thickness of one inch, two inch, etc. Within the broader scope of the present invention, for the deformation of the wood/fiber cell to achieve a distinguishable effect, the depth dimension of the floors of the valleys relative to the peaks of the ridges should be at least about 0.005″ (depending on the species of wood) to be noticeable. At a depth dimension of 0.01″ of deformation, the effect is more noticeable, and this would increase by increments of one-hundredth of an inch to greater depth dimensions such as 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0,09, and 0.1″. Obviously, this could be done also to greater depths, again with 0.01 increments (0.11, 0.12 inch, etc.) up to 0.15, 0.2 inch or greater.
After the wood has been embossed, it should be dried sufficiently before resurfacing so that the resurfacing process will cleanly remove material. This is especially important when steaming has been used as the plasticizing step.
Referring to
On smaller scale work where the embossing is light and where very little material must be removed, hand-scraping works well to remove the raised portion of the embossments.
Embossing changes the angle of the cell structure that is visible at the resurfaced surface 44. Some of the cell structure 46 is angled upward, with nearby cell structure 48 substantially horizontal. Since the figured effect relies on light reflecting off the reflective surface of the variable angled wood cell structure, it is important to make each cell as distinct as possible. In other words, the smoother the surface is, the more vivid the figure will appear.
The resurfaced surface is then finished with a stain and/or clear durable finish. Since the clarity of the figured effect depends on light reflecting off the uneven or undulating wood grain structure, it is important to apply a finish that is generally transparent. It is also important for the finish to penetrate and to fill the newly exposed cells in the wood surface. When well-sanded and finished, the appearance of the figure can shimmer or change when the angle of the light source and/or the viewer's perspective changes.
Through this process has been described in terms of a flat material, it is possible to apply the process to non-flat surfaces such as curved surfaces or decorative molding. For such shapes, the embossing and resurfacing process follows the desired shape.
Reference is now made to
The reoriented wood cells structure between line 54 and 52 is the area of preferred figured effect. The figured effect will be the most distinct within this area, with the effect diminishing the closer the resurfaced surface is to line 52.
The location of the lines 54 and 52 will vary depending on the extent to which the embossing process has effected the subsurface wood cell alignment.
Valley wood cells in the valley zone 62 above line 52, consist primarily of horizontal wood cells that will reflect light in a similar manner as the ridge wood cells in ridge zone 64 above line 52. There are the transition zones 66 between each adjacent pair of the zones 62 and 64, where there are the angled transitional wood cells 68 above line 52 that are undulating and reflect light in many directions and will shimmer as the light source changes. These are the cells in contrast with the valley cells 56 and ridge cells 58 that give the resurfaced surface 44 the desired figured appearance.
Let us now turn our attention back to
Likewise, the transition wood cells in the transition zones 66 can be considered to have a transition wood cell structure with transition wood cell structure portions being slanted and at higher and lower levels, and it can be seen that in that slanted configuration the transition cell structure portions slant downwardly from the related ridge wood cell structure portions to the related valley cell structure portions. Then, when the upper levels of the ridge wood cell structure portions are removed, the modified surface pattern is accomplished, as shown in
The embossment could be accomplished in various ways to accomplish various cell alignments in the transition zones. In
For many applications, this slant angle 70 could be only a few degrees (i.e., namely greater than zero degrees, and anywhere from one degree, two degrees, three degrees, four degrees, five degrees, six degrees, seven degrees, eight degrees, nine degrees, or ten degrees). At the lower angled slant the effect created may be more “subtle” in that the three-dimensional perception may be somewhat less “striking”. As the angle 70 increases up to five degrees, up to ten degrees, or various values in-between, the perception of greater depth would generally become stronger. Also, other factors may influence the effect produced by the finished surface, such as the structure of the wood, the angle or angles of the direction of the light may also be directed toward the surface being observed will have an effect.
In general, it would be expected that the maximum orientation of the angle 70 would be in the neighborhood of about one-half of a right angle, but even then it is possible for some applications where this could go to a greater angle, such as 50 degrees, 55 degrees, 65 degrees, or conceivably somewhat higher. For many of the applications now envisioned, the range from about five degrees or greater, possibly up to 15 degrees, with various degrees in one angle increments therebetween, would be a reasonable range. Nevertheless, for particular situations, and depending upon possibly around the character of the wood, the depth of the embossment, etc., these could be made greater in range between 15° degrees, 20° degrees, 30° degrees, 35° degrees, 40° degrees, and 45° degrees.
While all of the phenomenon which are involved in producing the visual effect produced by the present invention, may not be fully understood, it is believed that the following text would be at least a partial explanation of these. However, regardless of whether or not the following explanations are accurate or even in error in some respects, it has been found by actual experimentation that the results of obtaining the contrasting pattern in accordance with the practicing of the steps of the present invention are achieved.
When the upper woods surface portion is embossed, not only is the cell alignment modified, but also there would likely be a certain amount of compression of the wood cells. Further, when the plasticization step is accomplished, there is a softening of the lignin, and it is quite possible that there is a certain flow of the lignin from between the more compressed cells to possibly other adjacent portions of the wood. This also could have an effect on the appearance of the wood cells, the lightness or darkness of color, the reflectivity, and possibly other characteristics. Also, when some of the wood cells are at an alignment which is closer to perpendicular to the surface, it is quite possible that a number of these cells would be distorted laterally, in that they would collapse to one side or the other and be compressed in that manner. With the ridges removed and the wood surface finished, there is the contrasting pattern formed by the ridges and the valleys, but with the character of the contrasting regions being somewhat modified from those described above, relative to the more horizontal alignment of the wood cells.
The descriptions above and the accompanying drawings should be interpreted in the illustrative and not the limited sense. While the invention has been disclosed in connection with the preferred embodiment or embodiments thereof, it should be understood that there may be other embodiments which fall within the scope of the invention.
This application claims priority benefit of U.S. Ser. No. 60/353,533, filed Jan. 31, 2002.
Number | Name | Date | Kind |
---|---|---|---|
3536574 | Buckley | Oct 1970 | A |
3621897 | Vazzola et al. | Nov 1971 | A |
4231573 | Kelly | Nov 1980 | A |
4606388 | Favot | Aug 1986 | A |
5971045 | Watanabe | Oct 1999 | A |
6344101 | Graf | Feb 2002 | B1 |
6395204 | Neogi et al. | May 2002 | B1 |
Number | Date | Country |
---|---|---|
405076827 | Mar 1993 | JP |
Number | Date | Country | |
---|---|---|---|
60353533 | Jan 2002 | US |