US3081159A - Method for embellishing wood - Google Patents

Description

0. BROWN 3,081,159

METHOD FOR EMBELLISHING WOOD March 12, 1963 2 Sheets-Sheet 1 Filed July 18, 1955 INVENTOR.

Mamh 1963 0. BROWN 3,08 59 METHOD FOR EMBELLISHING WOOD Filed July 18, 1955 2 Sheets-Sheet 2 United States Patent 3,081,159 METHOD FOR EMBELLISHING WOOD Owen Brown, 5013- Exposition Blvd., Los Angeles 16, Calif. Filed July 18, 1955, Ser. No. 522,500 11 Claims. (Cl. 41-41) This invention relates to wood, to wood handling and re-surfacing machinery, to certain preferred methods applicable thereto, and to typical articles'which are the resultant products of said machinery and said methods.

While certain of the methods and the apparatus may be used in the processing of board lumber, selected edgebonded board stock and the like, they are particularly applicable to plywood sheets; and for this reason, without prejudice to sundry other uses, the invention will be explained with reference to standard laminated panels.

Furthermore, for reasons which will be clarified in due course, panels having rotary-cut face-plies of soft woodsespecially such as exemplified by Douglas fir, with its well-known random hard and soft grain figurations--are featured in the accompanying drawings, wherein a plurality of embodiments is shown. Certain of these drawings, including a major part of the present specification, in substance, were originally filed Sept. 18, 1948, under Serial No. 49,964 in a former co-pending application called Wood-Embellishing Means and Methods, Including Typical Products Thereof, which application was subsequently abandoned; hence the present application is a continuation in part thereof.

Problems of the Prior Art The method of subjecting plywood faces to the action of different abrading means, inclusive of both sand-blasters and wire-brushing devices, has long been practiced butuntil the past few years--without marked commercial success. This has been due, in part, to the high cost of manually sand-blasting such panels, failure to employ sufficiently fine-grain abradant grit at relatively low pressures, and the difiiculty of cleanly removing the surface soft grain wood without injury to the hard grain figurations.

In the case of wire-brushing, where sufiiciently stiff bristles have been utilized with adequate pressures to take out all or most of the surface soft wood, and at the required brush speeds, such bristles have also deleteriously affected the hard grain portions. That is, where the overlapped growth layers terminate, at their former areas of contact with the knives of the lathe-head at the plywood mill, the wire bristlesas generally employed-often produce clusters of objectionable lacerations. Moreover, because of the pitch and curl of the hard grain in some firwood face-plies, it has been extremely difficult to cleanly remove all of the softer wood from the deeper pockets formed here and there across certain of these veneers.

Recently, however, a machine has been developed which is said to overcome the first aforesaid difficulty, relative to the lacerations. I am presently informed that the heavy scratch marks are avoided by stationarily mounting a considerable series of rotary brushes having a fixed angular contact with the moving plywood surface. Thus, presumably, certain banks of rotating brushes are mounted for contacts obliquely of the panels, in one direction, while other banks, also obliquely positioned, contact the wood surfaces in an angular manner opposite to that of said first mentioned banks.

Machines of this type are apparently not yet capable, however, of removing all the surface soft wood from the aforesaid pockets of particular face-plies; and for at least 2,617,223, issued Nov. 11, 1952, to C.'T. MeElroy and John G. Davidson.

partially overcoming this difiiculty while, at the same time, providing improved and relatively much less expensive brushing machines which will not produce coarse brush marks, I herein introduce an especially compact mechanism of the type I prefer in carrying out the several objects of my invention.

General Objectives One such object is to provide, in a single machine, a plurality of wood configuring tools, one of which is an efficient, compact, low-cost brushing unit of the class described in common assembly with a particular kind of cutting head to be hereafter defined relative to FIGS. 1, 2 and 3 of the drawings.

Another object is to utilize such a combination machine as one preferred means for producing so-called spears or spear-heads, such as described in some detail in my previously entered application called Process for Ornamenting Various Objects, Including Means Therefor and Methods Relating Thereto, Serial No. 630,892, which has since been abandoned under that entitlement in favor of a former co-pending continuation thereof in part called Wood Ornamenting Means, Methods and the Products Thereof, the latter filed March 24, 1952, as Serial No. 278,281 but later abandoned.

Another object, in line with the last aforesaid objectives, is to utilize such a combination machine, along with other stepwise procedures, in the production of attractively predecorated panels, to be further detailed.

Other objects will be revealed in the remainder of this specification, as complemented by the claims and said drawings, wherein- FIG. 1 is a largely schematic plan lay-out of unified components comprising one preferred embodiment of the invention.

FIG. 2 is the fragmental detail of a plywood face-ply,

- featuring a combination decorative motif carried through to the finishing stage.

' FIG. 3 is a side elevation of one of the right and left stanchions on the machine of FIG. 1, bearing right and left oscillatory arms from which are carried the duality of rotary brushing wheels there shown.

FIG. 4 is the fragmental view of a plywood article which, by a minor modification of the cutting head, could be produced in part on the machine of FIGS. 1 and 3, and FIG. 5 shows another plywood fragment similar to the FIG. 4 article of variant type.

In s id former co-pending application bearing Serial No. 278,281, two general types of apparatus are provided, with the aid of whichas previously indicateda striated plywood panel can be further treated to bring out an attractive pattern of more or less pointed surface configurations called spear-heads.

Moreover, in another erstwhile co-pending application entitled Variegated Wood Products, Including Means and Methods Relating Thereto, Serial No. 33,246-now Patent No. 2,706,355 of April 19, 1955, bearing the amended title. Method of Producing Variegated Wood Surface and Productapparatus is disclosed whereby desirable portions of the soft surface wood may be abrasively and quite smoothly removed from a faceply, without producing lacerations in the hard grain areas; which latter remain substantially intact and are merely given .a high polish.

This beneficial result is achieved by brushing the Wood surface athwart the general grain trend, as therein related.

Now it is characteristic of machines having stiff brushing wheels which turn in the same direction as the grain trend that they will, under adequate pressure, produce the lacerations 2, as aforesaid: such as seen in the lower stationarily mounting difierent banks of brushing wheels to rotate obliquely against the panel surfaces from both sides-this set-up affording a diagonal movement somewhat comparable to the diametrically transverse action of the brushes in said last named co-pending case-this arrangement necessitates an expensive plurality of individual banks of brushing wheels, which, in many cases, would remove more of the surface wood than theoretically essential: that is, if the object is to remove only the soft grain surface wood, and perhaps at times, in accord with certain methods and articles to be hereafter described, leaving a portion of such surface wood above the harder growth laminations.

According to one mode of procedure, it is possible to thermochemically tone the face of a plywood panel, using so-called activatorssolutions made up from heat sensitive chemicals to be further amplified hereinwhich produce deeply penetrating tones in the hard grain segments and to thence remove the soft surface wood, only, whereby to bring out a more contrasty and more optically appealing effect than appeared originally. Copper sulphate and nitric and hydrochloric acid activators, for instance, are among those which may be so utilized; as see later, more specific reference thereto.

It has been found, however, that the desired effect is impaired if, during the brushing operation, any appreciable hard grain is removed along with the soft textured wood; and even if the hard grain be only taken from the frontal areas 3 of the growth ring laminae, at which places hydrochloric activators often produce attractive black markings at the very edges of particular hard grain layers.

The Brushing Wheels After repeated experiments, it has been determined that the hypothetically preferred action is one wherein the brushes rotate both transversely and obliquely; and this result, in a single automatic machine, has been accomplished without having to lay up the face-plies transversely (as explained in said Patent No. 2,706,355), and without having to provide an expensive dual series of stationarily mounted brushing wheels for right and left oblique con tacts with the panels.

In brief, said result is obtained by the expedient of mounting one or more brushing wheelsor, if required, sets thereoffor oscillatory movement.

Thus, in the more or less schematic view of FIG. I, a duality of typical brushing wheels 4 and 5 are provided, having respective arbors 6 which, in turn, are swivelmounted within forwardly and rearwardly disposed yoke members 7 of the right and left sets of wiggle-bars 8, socalled; one of which latter sets is shown for greater clarity in the detail of FIG. 3. For extra bracing, the bars 8 are inter-connected by the arm 9; and rotation of both brushes, in this particular assembly, is provided for by the train of belting 10 and 11 leading back to motor M.

Oscillatory movement of the brushing wheels is produced by the mechanism at left, subject to obvious engineering substitutions and adjustments, wherein the wigglebars on that side are integrated with a crank 12 projecting from the collar 13-si1nilarto collar 13 of FIG. 3. Crank 12 is pivoted to the pitman or link 14; and pitman 14 is also pivoted, as indicated, to a downwardly extending link (not seen) having the upper boss 15.

Said downwardly extending link operates, approximately midway of its length, from a stationary pivot (not shown in the relatively small drawing); and at its lower end is provided with the offset link 16 at lower boss 17. Link 16 is pivotally connected to the crank 18 extending according to this version-from a speed reducer and regulator group 19. The belting 2t) and complementary pullevs, associated with motor M, are self-explanatory, and the elements referred to as not seen and not shown will be so obvious, to skilled individuals, as to require no more than the above brief reference thereto.

Obviously, the turning of crank 18 on the gear box produces a forward and backward stroke of the pitrnan;

4 and, through said pitman, to crank 12, the resultant oscillation of the wiggle-bars S imparting like movements to the brushing wheels 4 and 5. It is apparent, of course, that instead of the specific arrangement shown a more direct hook up between the pitman and cranl: 18 could be provided.

The panels 21, 22 and the like may be moved relative to the brushing wheels in any desired manner, as here conveniently indicated by means of a plurality of chains 23 trained over the sprockets 24 and driven by motor M through belting 25 and 26 and the speed reducer 27. Very low pusher-dogs 28, for adequate clearance from wheels 4- and 5 and the blades of the cuttingheadto be explained shortlyare self explanatory. These could, by option, be replaced by a pusher bar (not shown) interconnecting all three chains; an alternative which is old and well known in the related art. Among the possible other options, of course, are a system of feed and suitably positioned back-up rollers, comparable to such as are shown in the hereafter referred to patent of Wilhelm Clefi.

The stanchions 29, FIG. 3, are each provided with upstanding posts 30 over which the collars 13 are journaled; and right and left compression springs 31, in combination with each movable adjusting sleeve 32having inner threads engaging threads 33 011 the upper area of post 3ilserve as automatic means to bring any desired pressure to bear on arms 8 and, therethrough, upon brushes 4 and 5 at their points of contact with the panel 21. As earlier intimated, each of the shafts 6 turns freely within the swivel-bearings 6.

Phantoms 33 and 34 represent hoods having conventional exhaust fans in combination (not shown), whereby to carry away the wood particles which are removed by the respective working heads.

Operating Means and Modes When panel 21, for example, is fed to the combination machine, each of the rapidly rotating brushes will describe an oscillatory pattern as generally indicated by phantoms 35 and 36. The oscillatory movements in either direction may be quite limited, however, and do sirably so, whereby to produce not only a brief sidewide scraping action against the direction of the grain trend but, also, in order to cause a continuous, instantaneous stiffening of the brushes within a narrow confines of each right and left oscillaiton: thus imparting a momentary, but sufficiently yieldable, gouging or digging effect at the hypothetical center of the oscillatory movement entirely across the panel surface.

This digging effect, under the required pressures, will not impair the hard grain; but, taking place as one component of a brushing action occurring continuously, and almost diametrically, athwart the general grain trend, it enables the brushes to exert a more effectual gouging away of certain soft wood tending to remain within pockets and the like, as was mentioned heretofore. Furthermore, such a result can be had utilizing wire bristles of small sizes; and the latter, where the wood has been first thermochemically pre-softened in the manner hereafter explained, may be as small as .005 (five thousandths) of an inch: thus further minimizing, or largely eliminating, the effect of brush marks.

It is evident, of course (where such a full-etched result is desired), that the cleaner removal of the soft wood, even from frequent panels having deeply sloping and curling hard and soft grain portions, is made possible by the combination of a nearly direct side-wise movement of the brushes in addition to said digging effect, which is also applied more or less sidewise of the grain trend. Such an action, and the resulting physical effect upon the wood surface, is obviously not possible where the brushes are only stationarily mountedeven though obliquely so with reference to the panels.

Moreover, since the panels themselves are traveling relative to the brushing head or heads, it is apparent that there is also continuously taking place an angular brushing contact which is the substantial equivalent of that which would be produced if the wheels 4 and were, indeed, stationarily mounted for oblique contacts; but with the added advantage, however, of the continually changing angular action coincidental with each back and forth oscillation. That is, at each reversal of movement-extending entirely athwart the panelthere is exerted a two-way gouging effect, as compared to a oneway effect, even where stationarily mounted brushes are obliquely disposed in oposed relations as aforesaid.

Because of the greater efficiency of brushing wheels 4 and 5, as soft wood removers, a much smaller number of brushesof a given bristle size and stiifness--can be used on a particular machine; but needless to say, the tandem thereof in FIG. 1 is only suggestive, and any desirable plurality of such brushing heads may be provided, and whether or not in different assemblies or driven from separate power units.

It is also provided that any preferred number of stationarily mounted brushing wheels 37 may, by option, be included in a given machine. Such brushes rotate in the same direction as the general grain trend, and could be only sulficiently stilf to aid in removal of the soft wood without producing lacerated areas 2, as in FIG. 2.

Moreover, in order to elfect a still cleaner removal of the soft wood where such a result is desired, either or any of the brushing wheels may be operated contrary to the direction of rotation of another or others of the as- .sembly. Thus, with reference to both FIGS. 1 and 3, for example, by merely criss-crossing the belt the brushing wheel 4 can be operated according to arrow 38, while wheel 5 turns according to arrow 39or vice versa according to arrows 40 and 41.

Other Procedures It is by now clear that when panels 21, 22 and the like pass entirely through the brushing head or heads they may, if additionally required, enter automatically under the feed-roller 42, having a suitable back-up roller-not shown-therebelow; thence passing under the cutting head 43 of planer type mechanism, which is provided with a requisite plurality of specially serrated knives 44. These knives, it will be seen, have areas 45 thereof formed to produce a considerable multiplicity of selectively narrow striations which, upon subsequent thermochemic processing to be explained, serve to define the innumerable small spears having spear-heads 46 of FIG. 2; some of which spears may be relatively narrower and wider than others of the same.

The areas containing spears 46, then, will be imposed according to one preferred pattern exemplified by the 'panel 1 of FIG. 2-in the form of bands 47; these bands, collectively, defining other spaced and wider banded areas 48 of the previously configured wood. This objective is accomplished by forming knives 44 with sufficiently deep gaps or skips 49, which are in exact registry with one another as are the areas 45.

Obviously, where the skips occur the closely spaced striations will not be imposed. And in order to produce the striations cleanly through the ridges of hard grain, as an operation subsequent to the removal of the soft surface wood, it is desirable to feed the panels to the combination machine with the grain trend as is customarily done in comparable other wood-working procedures; it being assumed that the knives 44 will be rotated contrary to the movement of the panels. Brushing element 37' is for smoothing the planer cuts. By option, one or more thereof could be mounted for this purpose; such as elements 4 and 5 and/ or 37, for example.

Incidentally, it will be readily apparent to skilled individuals that the conveyor chains could end at a point short of feed roller 42, where they would normally turn downwardly over other sprockets 24 (not shown); and the panels 21 and the like would thence be further moved solely by roller 42 along with any required auxiliary drive roller mounted on the delivery side of the work head 44.

The reason for mounting the cutting tool as shownfor later contact with the panels-is in order to fully overcome the possible difficulty of obtaining a clean removal of the soft wood, after imposition of the striations. Should it be found, in practice, that a fully satisfactory abstraction of the soft grain can be effected after the panels have been striated (a result which, parenthetically, I have accomplished since the original file date of the first entered application hereof, bearing Serial No. 49,964), I have no objection to reversing the relative positions of the kerfing and brushing components.

Right and left elements 21*, 22 are schematic guide means, and may be any preferred type thereof.

Although panels 1 may be additionally processed, in obvious other ways, I prefer thermochemic treatments whereby to accent the spear-heads while automatically imparting an attractive complementary toning to the intermediary zones or hands 48 substantially as shown.

Accenting the Spear-Heads Thus, for the effect seen in FIG. 2, the selected activator is a sufiiciently strong aqueous solution of copper sulphate; and while the activator may be made either somewhat stronger or weaker without materially modifying its thermochemic sensitivity and wood-toning character, my own solutions of this order are produced by dissolving 3 ounces of copper sulphate crystals, of the ordinary commercial grade, in each quart measure of tap water-the latter heated to speed up the dissolving action. The selected surface of the panel is impregnated with the solution, dried, and subjected to the action of a heating unit of the general class thereof disclosed in the aforesaid Patent No. 2,113,679 to Wilhelm Clefi and in No. 2,431,148 to F. R. Stover. Or see the comparable device shown in said former copending application bearing Serial No. 278,281. Such panels may be marketed unsealed or given a coating of any suitable clear protective material, such as nitrocellulose lacquer sanding sealer for example. The same, however, would not be normally sanded.

Before sealing, if desired, the panel 1 may receive a wash coat or impregnation of any satisfactory chromatic toner, exemplified by a saturated solution of picric acid or a selected aniline dye. Wherein such positive colorizers are relatively impervious to heat and have little or no chemical afiinity for the selected activator, they may, by option, be applied before the heat treatment. A more preferred embellishment, however, will be detailed hereinafter with especial regard to FIGS. 4 and 5.

Ordinarily, copper sulphate solutions, in the thermochemic process, will initially produce jet black tones in the soft grain to the virtual exclusion of the hard grain areas. But if localized heat of a sufiicient intensity is applied, the hard wood will also begin blackening at the edges of each hard grain area. It is this characteristic reaction of the copper sulphate activator which makes possible the attractive black tips at the spear-heads, as well as along the edges of the grain layers 48 and the sides of the spears, without darkening the pattern as a whole; that is, if the heat treatment is not unduly prolonged.

Another of possible formulas for darkening the spearheads and areas 48' involves the substitution of a compound solution of copper sulphate and hydrochloric acid, such as disclosed in my former copending but later abandoned application, Wood-Enchancing Method and Article, filed Jan. 20, 1955, as Serial No. 483,052. Such a formula, however, is best adapted to panels which have been grooved before thermochemic treatment; as see the later description herein relative to said FIGS. 4 and 5.

enemas Further Modifications As mentioned heretofore, it is sometimes preferable to additionally treat the panels 1 before applying a seal coat thereto; it being understood that such a coat could be omitted by the original processor and applied by the subsequent purchaser. In fact, some purchasers may, in order to obtain particular decorative effects, prefer to leave the panels unsealed and Without further processing. Attractive rustic or tropical effects, for example, may be had by modifying the chemical formula which was described with regard to said FIG. 2. article and omitting any sealer coat.

Thus, referring now to FIGS. 1 and 4, it is apparent that by a substitution of differently formed planer blades, so as to eliminate the deeper segments 49, the resultant panei 1 would-before further treatmentbeeome the striated equivalent of standard closely grooved panels commonly called combed plywood, and heretofore produced under Patent No. 2,286,068 to Donald Deskey. It may, therefore, be conveniently assumed that the panel 91 of FIG. 4 is either a modification of the aforesaid panel 1, omitting the broader bands 48, or the fragmental corner from a plywood sheet produced in accord with the Deskey patent, but further processed according to procedures which will now be described.

Panels of this general order are so closely grooved that their respective original grain patterns, in the natural, are substantially obliterated; the hard and soft grain portions being so nearly alike in natural tone that one thereof is but faintly distinguishable from the other. This applicant is believed to have been the first to discover that, when also etched and thermochemically toned in special ways, such grooved or combed panels could be largely transformedas to their general optical effectand their scarcely visible grain patterns brought out and enhanced by thermochemic treatments comparable in some respects to the photographic process.

Moreover, since the individual grooves and complementary ridge portions are quite narrow and closely spaced, when the outermost soft textured wood has been etched away, instead of the thus raised hard grain presenting an appearance such as seen at 3 in the broad bands 48 of FIG. 2, the multiplicity of spear-like spines 46 and the like will be produced as heretofore mentioned. But where such a panel, after an etching (brushing) operation, is then thermochernically treated, including the heretofore described application of copper sulphate solution, the remaining surface soft wood is not materially darkened; hence the contrasty effect seen in FIG. 2 where only the so-called spear-heads 46 have been intensely blackened.

It has been further discovered, in the interim, that a desirably less contrasty and more rustic or naturalistic effect may be produced, on such panel stock, whereby the blackened spear-heads may be retained and, in addition, the remainder of the face-ply toned to a mellow brownish shade admired by architects and interior decorators alike. And panels so processed may be used after a combination of thermochemic and etching" treatments, for rustic or tropical motifs, or may be somewhat further darkened and protectively covered by merely applying but a single coating of nitrocellulose lacquer or standard other clear sealer material thereto.

Concerning Activators To produce the effect generally indicated in FEG. 4, the surface of panel 91 is first impregnated with a thermochemic sensitizer--or so -called activatorcontaining both copper sulphate and hydrochloric acid in a watery solution. As disclosed copendingly, the exact relative proportions of the chemicals and the water component may be varied considerably without greatly altering the tonal effect obtainable therewith. However, after much experimentation, I prefer a compound solution produced by dissolving 3 ounces of copper sulphate crystals, avoir- 8 dupois, in each required quart measure of water (as already explained for making the straight copper sulphate activator), and by producing an acid solution comprising one part by volume of hydrochloric acid, technical, to each five parts of tap water. Then to each one part of the hydrochloric acid solution is added two parts by volume of the copper sulphate solution and the composite liquid well stirred for intermixing.

it is a natural characteristic of these two chemicals that, when thus combined, applied to the panel surface, and the latter subsequently heated, the normal thermochemic action of neither of them is lessened by the other; but each thereof cooperates with the other to produce a tonal effect of which neither of them, used apart from the other, would be capable. The copper sulphate, reacting therrnochemieally, not only blackens the surface soft grain wood but, in coaction with the hydrochloric acid, more rapidly blackens not only the ends of the spearlike spines (to be later delineated by brushing) but all sections thereof which are at surface level: this result being obviously superinduced by the additive action of the acid. Moreover, instead of having to carefully control the amount of heat to stop the blackening, as in the treatment previously explained relative to FIG. 2, the selected face-ply may be rapidly blackened throughout. This eliminates any need for carefully exactly controlling the amount of the heat applied to the panel surfaces. Heating apparatus of the general class disclosed in said Cleft and Stover patents may be used; and, after heating and blackening, each panel 91 is then ready for brushing. in small production, an ordinary gasoline blow torch may be substituted and manipulated manually.

The brushing stepwhich is preferred to sand-blastingcan be carried out in a machine such as seen in FIG. 1 but minus the head 44; or, alternatively, a single stationarily mounted rotary brush, similar to brushes 4 and 5, may be used. Lacking the oscillatory motion of the brushes 4 and 5, such a workhead will produce minute brush marks--assuming that the panels will be moved endwise as seen in FIG. 1. But owing to the fact that the thermochemic action of the activator greatly softens the outermost soft textured woodin fact, to the full depth at which the chemicals penetratedit is possible to use a brushing wheel having bristles so small and so pliant that such brush marks are scarcely noticeable. My own comparable brushing wheel has bristles of .005 inch; and this is a preferred size for use in the described process. Obviously if the oscillating brushes 4 and 5 are used, under light pressure contacts, a'ccmparable result will be had but without perceptible brush marks, longitudinally of the panel or otherwise; and it is clear that for use with such previously pre-softened panels, only one of the brushes 4- or 5 would usually be ample.

Following both therinochemic and brushing treatments, the previously striated panel 91 will now have the prominent, irregularly formed spines 92 and each of these terminating in the blackly accented, more or less well defined spear-heads 93. However, while the combined chemicals darkened the remaining soft wood which now lies at the new surface level (to the aforesaid mellow brownish shade), all of the blackened, previously outermost soft grain wood was removed. Thus, instead of all sections of the spines 92 being blackened, those areas of any thereof which previously lay underneath the removed soft grain, as at segments 94, were but partially effected by the heat treatment and merely toned to dark amber shades for the most part.

Moreover, according to the method which is preferred for producing the panel 91, a considerable portion of the soft grain surface wood remains: not only within the deeper parts of the grooveshere only indicated generally by the parallel recesses 95but frequently overlaying substantial, still unexposed sections of the hardgrain spines 92: as at segments 96.

Production Procedures Such panels, in this state, can readily be produced in volume with the use of power operated equipment for each of the respective grooving, impregnating, heating and brushing operations; and while I do not, in the present application, show mechanical means for applying the activator to the selected face-plies, the equipment for doing so may be inexpensively constructed in accord with well known devices of the prior art. See, for example, the coating device shown in Patent No. 1,026,921 to W. W. Nuss, in which a cylindrical fiber brush revolves partly submerged in a holder for liquid; which latter is picked up by the continuously wetted brushing wheel and applied to the underside of the work as it travels thereover. The particular value of this type of applicator resides in the fact that the liquid would not only be rubbed onto the surface of the panels 91 but worked well down into the grooves 95. Obvious other means may be utilized. Thus if it should be desired to apply the liquid from above, roller-coaters of well known construction may be used in train with a rotating fiber brush (not shown), the latter serving to work the liquid sensitizing material downwardly into the grooved portions. Of course the liquid may be applied manually, utilizing Tampico bristle brushes of the class called scrubbing brushes.

It isalso apparent that in volume production, the ,originallyun-striated .panels could travel continuously through grooving'apparatus such as the work head 44 of FIG. 1; thence-toan applicator such as described relative to said Patent No. 1,026,921, or one which applies the liquid from above; thence to a drying and heating unit exemplified by the aforesaid patents to Cleff and Stover; .and, finally, under a brushing head having one or two brushes 4 and/or 5 of FIG. 1, or only a single transversely ,disposed brushing head mounted for straight-over rota- ;tion co-longitudinally of thegrain trend, as previously explained and indicated generally in said Cleif and Stover .patents. The cost of the required chemicals would be negligible: 'thepresently estimated figure being less than /z cent for each fully impregnated 4 by 8 foot panel board. I

Still a further-and highly importantadvantage of [panels 91, in the state described, is the fact that they may .be additionally processed to tone them to almost any desired basic color, whereby to harmonize with widely variant interior decorative schemes. Thus they may be inexpensively further toned to approximately match or ,to complement the color of rugs and drapes; and where .used in single wall treatments, the remaining wall spaces may be of plaster tones according to the known color of ,the panels or vice versa.

Moreover, the toning of the panels may either be .done' bythe processor or by the purchaser. Where used .in large quantities in tract houses, for example, the ,buyerusually a corporati0nwould turn the panels 91 over to the painter or wood-finisher; and each panel in turn, having been laid fiat on a suitable table, with the grooved side up, may then be rapidly manually further treated as follows:

First a filler mix or slurry is made from ordinary water-dispersible dry colors. If it is desired to produce a basically White-toned panel with a predominantly black accent, the slurry may be made by intermixing so-called titanium white, of the kind chemically identified as rutile titanium calcium dioxide in a ratio, say, of 30 to 70 (that is, 30 per cent of the aforesaid substance intermixed with 70 percent of calcium sulphate used as an extender). One well known product such as described is produced by the Titanium Pigment Corporation and marketed under the brand name of Titanox No. RCHT-X; the desired amount of ordinary tap water being added to form a slurry of medium creamy consistency. In small production it is best to use a widely open container for this intermixed with the Water.

In small production, a convenient way to apply such a slurry, or so-called filler, is to dip it out of the container with a cup and pour it across the middle of the panel transversely. This operation is thence quickly followed by means to spread the slurry evenly over the remainder of the panel, forwardly and backwardly, an ordinary hand brush filled with Tampico fiber bristles being sufficient to both spread the slurry and to simultaneously rub it well into the grooves 95. Immediately thereafter, the surface of the panel may be rapidly wiped down with a nitro-cellulose sponge which was previously wetted and wrung out but let in a moist, softened condition. However, a more preferred Wiping step will be explained shortly.

This operation will not only smooth up the pigmentation produced with the aid of the Tampico brush but will, in large measure, remove that portion of the filler or slurry which previously covered the high areas; mainly where the exposed hard grain is present. All of the soft grain areas will take up a sufficient amount of the slurry to become opaquely coated and impregnated, and the slight remaining film of pigment over the hard grain spear-heads 93 and the like can thence be quickly largely removed by a rapid wipe-off, using a No. 2 moistened sponge which has not become loaded with pigment. .For the effect of a cleaner wipe-off, however, it is preferable to quickly and finally rub the whole panel surface lightly with small pads of paper, such as the calendered pages from old telephone directories, which are conveniently halved at the center and each half page folded twice to form a wiping element of handy size. The resultant panel has an attractive tapestried elfect, being richly accented but not over-accented.

An alternativeand preferred-method of clearing the ,hard grain, following the rubbing in operation with the Tampico bristle brush, is to again rub the surface with a wiping device having a flexible rubber squeegee blade:

.such as are commonly employed as window wipers. In

the latter case, the final wipe oif with paper is not essential, but all of the ridge portions defined by the striae should be on substantially the same surface plane.

In short, if any of the ridges are deeply recessed, they would not be contacted by the squeegee blade.

(It will, of course, be understood that these procedures relate only to such small production jobs as may, for

"example, be performed by the average painter or homecrafter.)

A Preferred Method Applicant prefers this Wipe-off operation, utilizing a yieldable squeegee or doctor blade, so-called, to the sponge method for the reason that sundry of the described spearheads tend to become snagged against the No. 1 or No. 2

'spongesand even worse where conventional wiping rags are attempted. Moreover, since the spears often are pointed in two directions, the difficulty cannot be overcome by merely wiping with the grain trend. The problem is one which is peculiar to the particularl products herein disclosed, having said pointed spear-heads, and much experimentation was conducted before the most approved method was discovered: that is, by utilizing'a to one which can be speedily performed with motorized equipment. See, for example, FIGS. 7 and 9 in my prior co-pending but since abandoned application called Multidecorated Wood Product, Its Method of Manufacture, and Means Therefor, filed Sept. 18, 1948, as Serial No. 49,963.

Panels so treated can be stacked or leaned against one another until dry, when they will be ready to receive a protective seal coat as referred to heretofore. Such a coating may be brushed on, or, preferably, applied on the job with a portable spray gun. Needless to say, these operations may all be performed in the plant of the original processor with the use of existing or readily constructed types of power-driven equipment. But since such equipment is not per se claimed herein, and the manual method will sufiice to readily carry out the essential steps, the same are not graphically shown or described.

Those skilled in the mixing of pigment colors will require no further instruction wherein the basic tone of the panel 91 is to be some selected color instead of white. One or two desirable formulas will, however, be given for the benefit of those who may wish to try out certain color shades experimentally before adopting the one or ones most suitable for particular effects. Thus one kind of gray mix may be produced, in small quantity, by utilizing with each four ounces avoirdupois of titanium white a level A teaspoonful of drop black in dry powder form. For this purpose the small plastic or metal spoons sold to housewives for culinary purposes will be satisfactory. The pigments are mixed to a medium creamy consistency with tap water, as described hereabove, and applied to the panel in the same manner with like wiping operations.

If a warm dark beige basic tone is desired, the slurry may be made in the proportions of titanium white 4 ounces, ferrite two level teaspoons full, metallic brown iron oxide two level teaspoons full, and drop black dry powder level teaspoonful. Water is added as required. Applicant in his own slurry mixes used C. K. Williams & Co.s metallic brown oxide No. B-2390 and their grade of ferrite (ferric iron oxide) having the stock number Y05087. This supplier has plants at Easton, Pa., East St. Louis, 111., and Emeryville, Calif, and sales offices in principal cities. The main headquarters office of the Titanium Pigment Corporation is at 111 Broadway, New York City, N.Y.

Varying the Basic Formula The number of possible thermochemic procedures is by no means limited to the ones described, relative to the panel 1 of FIG. 2 or the panel 91 of FIG. 4. Thus, as one of sundry possible other treatments, the effect seen in PEG. 5 may be obtained by still another modification in the thermochemic activator. In this view, the previ ously grooved face-ply of panel 97 has been impregnated with a compound solution comprising desirable proportions of copper sulphate and nitric acid, and usual technical or commercial grade being satisfactory. As with respect to the compound solution of copper sulphate and hydrochloric acid, the proportions of each may vary greatly without critically altering the general result to be attained. It is, however, necessary that a suflicient amount of the copper sulphate be added to the water component to obtain blackish tones in the surface wood in the presence of locally applied heat, since, in this formula especially, such a reaction is necessary in order to both tone the face-ply and to thermochemically soften the soft textured portions of the wood surface as a pre-requisite to the subsequent brushing operation-according to the procedure given relative to panel 91. The particular reason for this, in relation to panel 97, is that nitric acid, in the proportions used, has little or no wood-softening action, and only a wood-toning action upon application of suitable heat. However, such a compound solution must, also, contain a sufficient amount of the nitric acid Li to produce distinctly reddish thermochcmic tones in the wood, which it will do without reference to the copper sulphate in solution with it.

After many experiments, this applicant arrived at preferred proportions of the respective ingredients comparable to those employed with respect to the panel 91. In brief, a preliminary solution is made by adding five parts of tap water to each part of the nitric acid; and to one part of the resultant liquid is thence added two parts of the first mentioned copper sulphate solution, produced by dissolving about three ounces of the dry crystals in each quart of tap Water. The composite solution, or activator, is thence applied to the panel surface and the latter dried and heated in the manner heretofore detailed.

The more heat-sensitive nitric acid will, initially, quickly react in and with the surface woodboth hard grain and softto produce reddish tones shading toward burnt orange. This reaction is quickly followed, however, by an independent reaction of the copper sulphate component; the latter changing the previously reddened soft grain surface wood to black and, if the heating action be sufficiently intense or sufficiently prolonged, it will also produce blackish tones at the tips of the spear-heads 98. Ordinarily, it is not preferred-for the effect seen in FIG. 5-to carry the heating step beyond the stage at which the surface soft grain wood is fully blackened; after which the panel 97 is preferably fed to a mechanically operative brushing element in the manner explained relative to panel 91.

The brushing operation will remove substantially all of the blackened surface wood, bringing out and leaving the spear-heads 98 of the previously exposed hard grain relatively darker in tone than those segments thereof which were below the original surface prior to the brushing action and, hence, less affected by the heat. Such protected but now also exposed areas will be lighter in tone, shading gradually darker toward the spear-heads substantially as shown. Thus the greatest contrast occurs where each spear-head overlaps the lamina immediately adjacent the same, whether the adjacent wood be the hard grain of the next adjoining spear or a segment of the re-exposed soft grain Wood.

The panel 97 may be marketed in this state, or may be sealed with a single coat of clear nitrocellulose lacquer of any selected well known type; or any elected other clear sealer material may be used. Panels so treated are especially suitable for warm reddish brown color schemes, and go especially well with real maghogany or so-called Phillipine mahogany trim: also as paneling on fireplace walls to harmonize with red brick fireplaces. Obviously, too, they may be further processed in any desired manner, such as by the pigmentation and wiping treatments explained relative to the FIG. 4 panel.

Although certain preferred expressions of the invention have been disclosed, these are primarily illustrative of the possibilities. The invention, therefore, is not to be limited thereby, but rather by the language of the properly allowable claims hereto.

I new claim:

1. The method of removing relatively softer textured surface wood from the contiguous harder grain portions thereof on the selected face-ply of a plywood panel, which comprises positively abra sively brushing said faceply in respective rotative and oscillatory manners simultaneously while said panel, itself, is in continuous movement, which procedure includes: imparting said movement to said panel and applying a laterally continuous to-and-fro sidewise motion to the primary driving means of the brushing means.

2. The method of toning and of mechanically configuring a wood surface which includes impregnating said surface with a compound aqueous solution containing a known quantity of nitric acid as well as a known quantity of copper sulphate; heating said surface until 13 both blackish and reddish tones are thermochemically developed in the respective softer and harder textured surface wood; and abrasively removing a component of the outermost softer grain portions thereof.

3. The method of toning and blackening a wood surface thermochemically which includes: impregnating said surface with an aqueous solution containing a known quantity of liquified copper sulphate of a known strength and wood-sensitizing property in the presence of adequate heat; drying said surface; and heating it until the desired amount of thenmochemic blackening has taken place therein.

4. The method of removing relatively softer textured surface wood from the contiguous harder grain portions thereof on the selected side of a wood-surfaced object, which includes positively abrasively brushing said selected side thereof in respective rotative and straight-line oscillatory manners variable to-and approximately right-angular to-the longitudinal axis of said object while the latter is in a substantially continuous one-way movement; which procedure includes imparting the required movement thereof to said object.

5. The method of toning and darkening a wood surface thermochemically while softening an outermost component of the softer-textured surface wood, which includes: impregnating said surface with an aqueous solution consisting solely and normally of a plurality of known thermochemic wood-sensitizing and wood-toning active components thereof, one of which components is copper sulphate; impregnating said surface with said solution; drying said surface; and heating the same until the desired amount of thermochemic toning has taken place.

6. The method of removing relatively softer textured surface wood from the contiguous harder grain portions thereof on the selected side of a wood-surfaced object; namely: by positively abrasively brushing said selected side in respective rotative and oscillatory manner simultaneouslysaid rotative and oscillatory actions comprising concurrent plural (respective) movements of the same brushing means-while said object itself is in continuous motion which procedure includes imparting constantly repetitious motions of oscillation to the primary driving means of the brushing means and the required movement thereof to said object.

7. The method of removing relatively softer textured surface fibers from the contiguous harder textured grain portions of a wood-surfaced object, which comprises: imparting a continuous one-way movement to said object and positively abrasively brushing a selected side thereof both rotatively and regularly repeatedly in a laterally continuous to-and-fro manner crosswise of the normal grain trend, as well as regularly repeatedly forwardly and backwardly of a common axial center of the rotational movement.

8. The method of removing relatively softer textured surface Wood from the contiguous harder grain portions thereof on the selected side of a wood-surfaced object which includes: non-reliably brushing said side rota- 14 tively while moving said object along a path of travel contrary to the directional motion of rotation, and the concurrent further brushing of said surface positively ab-rasively in a transverse to-and-fro axially swingable manner.

9. The method of toning a wood surface thermochemically which includes: impregnating said surface with a compound aqueous solution, comprising known respective amounts of liquified copper sulphate and nitric acid, of a known composite strength and wood- :sensitizing property in the presence of the required intensity of heat; drying the surface; and heating it until the desired amount of thermochernic toning has taken place therein.

10. The method of brushing away the outermost soft textured fibers from a wood-surfaced object having relatively harder and softer grain figurations, with a desirable minimum of visible brush marks, which comprises: continuously moving said object in a one-way path of travel while concurrently brushing said surface positively abrasively, and both rotatively and regularly repeatedly athwart the normal grain trend thereof; which latter procedure includes brushing said object in a transverse to-and-fro swingable manner.

11. The method of toning and blackening a wood surface thermochemically which includes: impregnating said surface with a compound aqueous solution, comprising known respective amounts of hydrochloric acid and liquified copper sulphate of a known combined strength and wood-sensitizing property in the presence of adequate heat; drying the surface; and heating it until the desired amount of thermochemic toningincluding said biackeninghas taken place therein.

References Cited in the file of this patent UNITED STATES PATENTS 749,004 Wadamo-ri Jan. 5, 1904 764,872 Stewart July 12, 1904 1,431,917 Antaramian Oct. 17, 1922 1,566,985 Shuler Dec. 22, 1925 1,794,194 Meyercord et al. Feb. 24, 1931 1,802,069 Schmid Apr. 21, 1931 2,024,257 Snelling Dec. 17, 1935 2,431,148 Stover Nov. 18, 1947 2,467,194 DeWitt Apr. 12, 1949 2,617,223 McElroy et al. Nov. 11, 1952 2,634,534 Brown Apr. 14, 1953 2,635,653 Hennell Apr. 21, 1953 2,706,355 Brown Apr. 19, 1955 FOREIGN PATENTS 652,508 Great Britain Apr. 25, 1951 OTHER REFERENCES chapter 13, pages 269-298; at page 281 in particular.

Claims (1)

1. THE METHOD OF REMOVING RELATIVELY SOFTER TEXTURED SURFACE WOOD FROM THE CONTIGUOUS HARDER GRAIN PORTIONS THEREOF ON THE SELECTED FACE-PLY OF A PLYWOOD PANEL, WHICH COMPRISES POSITIVELY ABRASIVELY BRUSHING SAID FACEPLY IN RESPECTIVE ROTATIVE AND OSCILLATORY MANNERS SIMULTANEOUSLY WHILE SAID PANEL, ITSELF, IS IN CONTINUOUS MOVEMENT, WHICH PROCEDURE INCLUDES: IMPARTING SAID MOVEMENT TO SAID PANEL AND APPLYING A LATERALLY CONTINUOUS TO-AND-FRO SIDEWISE MOTION TO THE PRIMARY DRIVING MEANS OF THE BRUSHING MEANS.

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