US2147587A - Coloring of bent wood products - Google Patents

Description

Feb. 14, 1939. w. c. WHYTE 2,147,587

COLORING OF BENT WOOD PRODUCTS Filed May 25, 1937 INVENTOR. WILL/HM C W y 7-5 ATTORNEY aw Feb-14,1939

COLORING OF WOOD PRODUCTS William C. Whyte, Cortland, N. Y., alslgnor to Cortland Line Company, Inc, Cortland, '-aoorpmtionofNewYork I Application my :5. 1m, Serial No. 144.000

REISSUED.

'1 Claims. (Cl. 273-73) This invention relates to improved artificially colored articles comprising tenacious, brilliantly dyed hardwoods and more especially as applied to bent tennis racket frames, snow shoes, skis,

trout landing net hoops-or the like set shapes of arcuate contour. My yed wood may be penetrated in a uniformly diffused manner to afi'ord a substantially bright appearance throughout the .frame body and to impart an attractive, durable "L and non streaky surface finish thereto thatshall not peel or scruff oil.

The harmful effects resulting from the suecessive hot dyeing, bendingand forced drying of such wood products may be minimized by consistently restricting the temperature intensity and by fixing upon the allowabletotal heat treating time required to complete all operations thereon. 'lfhe pr'esent improvements strive to so control the necessary combined treating steps as to substantially obviate their accumulative detrimental; heating effects upon a finished bent wood a product, particularly as regards its shock absorbing property against impact loading. In addition, my hot dyeing treatment to some extent improves the properties of a bent laminated racket in that augmented frame rigidity and hardness are imparted thereto over its original plywood stock. a

The same dyeing procedure admits. of fabrieating a hoop shaped frame from a single or.

different specie of laminated wood in which the respective outer or inner plies prior'to gluing, may be dyed in'spectral hues. in a contrasting or harmonizing color scheme to heighten its decorative appearance as a distinctive marketable commodity over the corr nding use of woods in natural colors. types of artificially colored racket frames are made to preserve adequate tensile strength and other inherent qualities by resorting to a suitable primary grade of wood that will effectively meet I over a prolonged period of usage, the arduous requirements (if a batlike ball striking implement without latent flaws or superficial discoloration.

The preferred grade of hardwood to be em played in the fabrication of my dyed racket fran'ie or the like, is second growth, commercial white gash, particularly its selected straight-grained or 'ciearsapwood which may bemade to preserve its g any desired bright coloring matter, preferably Both, the solid and laminated,

certain kinds of water soluble, organic acid dyestuffs of an extremely soluble character, since apparently not all of the so-called anilin or the like synthetic dyes react in the manner herein contemplated. The cited white sapwood of ash ranks relatively high in specific gravity, tensile strength, toughness against impact loading. bends flawlessly in relatively thick plies, and retains its set shape to'a marked degree after being bent to form. 10

The fact that such wood does possess a low volumetric shrinkage from a green state into an oven dried condition, together with its relatively small natural moisture content, assumes significance in restricting the tendency to swell, to 15 straighten out with increased moisture absorp- 1 tion, or otherwise alter the original arcua'te shape a 'of a bent frame when subjected in use to an anticipated rather wide degree of change in atmospheric humidity.

A varnished, painted or shallow stained surface finish for a tennis racket frame or the like is susceptible to weather conditions and its inherent color frailty may ultimately lead to an unsightly worn appearance. Such superficially applied coatings tend to disintegrate with age by cracking or flaking, especially as regards the swinging arched head of a tennis racket whichis likely to suffer rapid abrasion inactive service. By virtue of a uniform dye impregnation, my 30 frame head will not reveal a different underlying color, although subjected to severe knocks or long repeated ground scraping. A shaped up product of this kind may also during its manufacture,

be deeply shaved oil. and sanded without change. in color.

Furthermore, tennis racket frames and the handles thereof not only call for ample inherent strength, but should nicely be held to a definite body size to provide for the requisite heft and 0 resulting fine balanced feel that will wholly satisfy professional playing needs.

In order to realize the maximum break down capacity in a bent laminated racket frame, it is expedient to provide for a high degree of longitudinal shear resistance in each component ply thereof. In accordance with conventional decorative practice, a soft wood inlay is commonly inserted between stronger ash plies in their respective natural colors. An interposed laminago tion' of this species possesses a low shear strength and hence is likely to correspondingly weaken a completed laminated frame. Under break down bending tests, many of such conventional inlays have'been found fail fromlengthwise'grain factory performance.

shear between the glued ply faces thereof. By resort to a dyed wood inlay possessing a markedly higher inherent shear property, it becomes possible by dyeing, to obtain a far wider color selection together with increased strength at a materially lowered fabrication cost, thereby not only more effectively utilizing cheaper grades of American woods such as white ash, but at the same time obviating the cited grain shear frailty on part of a conventional softer inlay.

In addition, my innerand outer frame plies may without harmful results, be dyed to a color that sharply contrasts with their inlays. Woods that present a sharply defined natural color, seldom afford a straight grain cleavage and when attempt is made to use such weaker woods as a heavy ree'nforcing outer Ply. they frequently fracture upon being closely bent to the required shape. The instant innovations pertain to the refined fabrication of a high grade racket frame without allowing its decorative pattern to wear off under prolonged usage.

The fabricating of a tennis racket that shall prove acceptable to experienced players by satisis a difficult art. Present day bent wood tennis frames are required to possess in high degree, appropriate qualities that can only be attained by selecting the most suitable wood species. Any substantial deviation from this exacting standard has generally been foimd unacceptable to thetrade, it being emphasizedithat a proportionate drop of less than onehalf of the maximum attainable break down strength of a conventional all ash racket; is

likely to result in its complete commercial relection.

The instant ballimpelling frame is preferably dyed prior to the moist bending thereof into a required hoop or other arcuate shape, whereupon the partially treated article may be subjected to intensified or oven drying to remove surplus'moisture at a comparatively rapid rate. Any permanent injury resulting from such forced drying or discoloration into a comparatively dark shade of the frame stock, may .be materially mitigated by a careful control of the temperature elevation of the dye bath and drying over by definitely restricting the'total time during which any high temperature is applied, the heat treatment in its entirety being herein deliberately terminated prior to permitting the residual bending strength of the treated wood to become inordinately lowered or allowing a brilliant spectral color to become vitiated.

. The primary object of the present invention is,

to fabricate a neatly trimmed, decorative racket frame or 'the like bent shape of either solid or plywood that is dye impregnated in one or more artificially colored base woods, the goal being to generally work for the optimum as regards the application of a durable brilliant pattern or other pleasing color scheme to h wooden structure and thereby provide superficial discoloration under prolonged hard usage and its result! "ing wear.

Reference is had to the accompanyi one sheet of drawings in which:

figs. 1 and? respectively represent a face and an edge view of a tennis'racket treated and equipped in accordance with my invention.

Fig. 31s a cross-sectional viewof a solid racket frame as taken along line 8-4 of;l"ig.1. I

mg.,4 is similar. to Fig. 3 but illustra es a laminated in lieu of a solid racket frame,

. heat treatment, whether amass? Figs. 5 and 6 detail a modified frame overlay of the laminated type.

Fig. '1 fragmentally represents a laminated racket frame provided with another style of decorative overlay.

An outstanding requirement in obtaining a socalled brilliant or bright dye shade in distinctive colors, resides in maintaining the natural white or the like pale color of the sapwood (alburnum) portion of ash, or the like hardwood species against scorching without substantial darkening by chemical changes; also in not allowing the treated wood fibers to become embrittled or brash to an extent that will seriously impair the shock resisting qualities and durability thereof under fatigue loading, nor to other- -wise substantially affect the wood life for subsequent close bending particularly as applied to racket purposes. Incipient stages of decay induced by excessive temperature, are usually accompanied by a visible discoloration and may cause heat treated wood to undergo pronounced permanent weakening under impact loading.

Such impairment is augmented in a proportionate relation to excessive temperature exposure, wood being increasingly injured with a prolonged applied during the dyeing or the drying steps. That is to say, the resulting loss in bending strength is accumulative and tends to progressively darken the natural sapwood color by such scorching effects to a point where the dyed colors of a lighter shade may be obliterated by a darkened background and thus materially neutralize or otherwise vitiate certain color effects herein sought.

In order to secure adequate penetrationat a rapid productive rate that will produce a uniformly distributed, non-streaky woods,-I preferably but not necessarily resort to a hot. dye bath held under pressure but limit the exposure thereof to relatively high temperature for a restricted period that will notseriously impair its toughness to shock nor allow its initial pale shade to become darkened sufficiently to overpower theparticular anilin dye or some other 4 brilliant coloring agency such as scarlet, canary, copenhagen blue, emerald green or the like spectral hues, in which it is more particularly intended to dye my bent wood frames.

As an exemplification of a preferred procedure, the following treatment secures the results herein contemplated. Selected white ash sapwood stock may initially be cut into relatively long strips having a cross-sectional thickness of about 95" as suitable for making an unlaminated tennis racket orsnow shoe frame of which the grain runs lengthwise without abnormal diagonal slope. A large batch of such strips, stacked in spaced relation may then be set upright on end and immersed in a brilliant dyeing solution held under pressure in a closed jacketed container (preferably porcelain lined and free from the presence of iron or otherv metallic element likely to affect the dyestuff). The wood should be reasonably dry before immersion since excessive moisture content tendsto resist color absorption. Said aqueous bath preferably contains a water soluble anilin dye of the character previously indicated and said wooden strips may under favorable conditions, be initially heated in such solution by steam or other means to about 250 for less than one hour's time, it being evident that the stipulated temperature may be raised or lowered .within reasonable limits, depending upon the parcoloring in hard process without 'need of fresh" steam, whereupon all the processed wooden strips become impregnated to a substantially uniform shade. My initial'steam heating suffices to maintain the dye bath 'at an' elevated temperature with respect to the atmosphere until the color processing is completed. If desired, the usual pro-vacuum process may also be resorted to in facilitating dye impregnation, but this is not essential.

In attempting to color a batch of ash' strips in a brilliant spectral hue, the dye hot bath should not be allowed to act for "an unduly long period otherwise the bending strength of the dyed wood is likely to suffer material impairment. The treated wood body first becomes superficially penetrated by the dye and finally reaches saturation, whereupon it is preferred to terminate the dyeing operation by removing said strips from the closed container. Should the hot dyeing especially above212 F., be unduly prolonged, the tendency is first to superficially scorch the, wood toward a dull brown shade, which with continued excessive processing creeps inwardly and finally becomes diffused over the whole cross-sectional profile of a .dye treated wooden strip so as to dominate the desired color shade.

While in a water saturated state, such pliant and brightly colored ash strips may individually be sharply bent without substantial fracture and retained about a suitable forming fixture to dry thereon into a looped tennis racket frame represented in Figs. 1 to 3. In this illustrative embodiment, a. solid frame member i after being 'dried and set, is given a closed hoop shape having the respective strip end regions extended into subthree bonded components including a dividingwooden center spline ISA which latter may be distinctively dyed in a brilliant color shade that contrasts with the adjoining components to constitute a characteristic emblem by which to identify my decorative rackets to the purchasers thereof.

Such frame structure m y be further fortified by -a glued crescent reenforcement l4 and by 7 separate fiat overlayssuch as I! or ISA but either type of overlay may be extended into unitary formation as in Fig. -'l. Each opposed .handle side face or pallette' may ave one or more reenforcing layers or plural cheeks i6 glued thereon insuperlmposed relation to enlarge the ban;

die girthand toenhance its decorative display. The closed hoop perimeter may be drilled in multime to thread the interwoven web strings n therethrough.

'After the'aforesaid dyed name'stnps have respectively been bent into hoop shape, theymay be transferred into a kiln or the like agency to hasten'the drying thereof while still mounted and held around a separate forming fixture, care being taken not to overheat such bent frames so as avert honeycomb and celi collapse,

also to prevent abnormal discoloration of the treated wood or the dye impregnation thereof.

Bright anilin dyes when exposed to high temperature for. a prolonged period,,tend to go over into a darker shade and it is the present aim to obviate such color degeneration by suitably controlling my processing time and temperatures. When too rapidly kiln or oven dried, opposed side faces of the treated frame strips are by abnormal core shrinkage, likely to sink into a cupped formation which may interfere with tight gluing, especially as regards superimposed fiat plies or veneer reenforcements.

Bald kiln drying or oven baking is preferably temperature at high humidity and then gradually changing over to a maximum temperature not in excess of 200 F. at a. relatively lowered humidity. The accelerated drying process usually requires some 12 to 24 hours after which the set bent frames ihay be taken out of the kiln at a moisture content somewhat below 6 to 8%. When seasoned to atmospheric condition, the removed frame is made ready to have a throat piece and overlays applied thereto by a suitable adhesive such as animal or casein glue. v

In the event flat shoulder overlays or handle layers are provided, they may be dyed and kiln dried in accordance with the same process prescribed for the frame strips after which they may be applied into place. If preferred, a group of my potential frame making strips may initially be dyed and bent up as a whole in boardlike formation, which is subsequently cut into separated racket forming units.

By my refined treatment, undue darkening of the treated wood is not allowed to occur and this in turn, correspondingly prevents serious deterioration of the shock absorbing qualities of 'a bent racket frame or the like ball impelllng implement. When so restricted, the heat treated wood stock is not subjected to sufilclent darkening to vitally interfere with the application of brlllint dye of a pale shade. 'The use of air pressure in following "up the initial steaming, tends to preserve the original 'pale shade of heat treated wood stock. While the use of lower than stipulated temperatures would prolong the process somewhat, the prescribed treatment has been found to afford a commercially useful bent wood frame that retains a high degree of its original strength.

The use of dissimilar species of more costly wood plies possessing contrasting natural colors, is not so well adapted to fulfill exacting frame specifications in so faras their relatively lower intrinsic strength anddiverse higher shrinkage properties are not of the same favorable charactor as those afforded by less costly ash, nor can the same brilliant decorative efiects be achived in natural colored woods.

As a result of extensive comparative tests, I have determinedthat ash racket frames after being dyed. bent and dryed,'may be upheld to substantially the same inherent strength possessed by a corresponding undyed ash frame. Plywood when processed in accordance with the herein prescribed dyeing treatment, is further found'to enhance both the hardness and rigidity over anundyed frame of equal size. The somemented rigidity reduces frame warpage when subjected to a high initial stringing tension.

Under favorable circumstances, heart-wood or duramen may be treated by a process similar to 5 that described, but in such event the final color may be expected to become somewhat darker in shade than the natural wood. Heart-wood is inherently difficult to penetrate uniformly but such dye distribution may be facilitated by cut- 10 ting the wood into relatively thinner slats to more adequately surface the same. Colored slats of this kind may be glue assembled into laminated plywood in the Fig. 4 manner and then bent up into nested hoop shape.

15 In practice, after having cut ash boards into solid frame strips wholly of either sap-wood or of heart-wood, there remains a certain amount of scrap which may be utilised by further cutting the same into relatively thin slats. Such 2o surplus material may likewise be dye treated in the prescribed manner and worked up into iaminated racket frames i i of which adjacent nested plies may be given harmonizing or contrasting colors. If desired, an inlay of thin basswood,

gs poplar. birch or the like in either their natural state or in an artificially colored condition, may likewisebe incorporated and glued between certain of such dyed. plies. When different plies of such laminated wood are to be contrastingly so dyed, each color requires a separate bath. By -.virtue of such treatment, the distinct hues of my laminated frame present a'sharp demarcation therebetween without need of any interposed a In a like manner, the throat overlay IIA may be laminated around the curvature axis 18 of the bent frame in the nested fashion indicated in dotted outline in Fig. 1 and worked up into different colors to correspond 'in matched registry with the plies exposed along one frame side face. In such event, diversely colored segments of my unitary crescent shaped overlay may be bent up from straight stock and otherwise treatedinamanneressentially similartotheprocess preferably dye lmp smt d in distinctive spec-- tral hues constituting a striking decorative frame him that is primarily centered in its hoop-shape and handle neck region 20. The crotch region of such frame may have a throat piece 21 bonded therein. The slat end portions again extend, outwardly away from such forked crotch region into an integral handle member I. of which the interposed neckregion is preferably contracted wlthrespecttotbegirthofthehandlegrippobtion. An ornamental overlay such as It may be superimposed to cover a side face portion of the throat piece and to span the respective forked 70 regions of the bent slats IIAJIB, etc., as shown,

said overlay being laminated in upstanding edgewise registry with corrupohding underlying slats in matched color schemeto virtually complete a series of endless bands arranged concentrically 7 abouttheaxisli andtherebyenhancinglyalter the embellishment afforded by the aforesaid color trim.

By these means. it becomes possible to achieve strikingly beautiful decorative effects and overlay modifications thereof as applied to racket purposes not heretofore attainable in natural wood colors. As an illustration, a de luxe laminated frame comprising adjoining ash plies may be dyed in delicate harmonizing light and dark shades of a preferred color such as either blue, green or red, D

and when such different tones of a single brilliant color are assembled, they provide for an exceptionally attractive racket adornment that will not wear off. Complementary thereto, a series of handle reenforcing cheeks such as It may be similarly dyed to impart a contrasting or harmonizing color scheme thereto, the respective overlapping forward cheek edges as at ISA then being preferably stepped and beveledto simulate a quarter sawed effect.

-As a further variant, a fiat overlay such as 2|! may also be applied to the side face of a racket frame. As separately detailed in Figs. 5 and 6, such overlay may be laminated fiatwise and have certain plies artificially dyed in diflerent colors 25 being completed without allowingthe dyed wood to become materially darkened to an extent that, will vitiate the sought for matched color shade. In the case of dyeing heart-wood to a mahogany or-the likedarker color, the anilin dye bath and length of total heating treatment must still 03 be proporly controlled 'for present purposes in order to counteract superficial discoloration by scorching and not allow the dye bath by leaching to go off'color to a different shade while treating such wood. For instance. when dyeing a racket 4 frame to a delicate brown color tone, the steaming temperature's hould be duly limited as to processing time to insure a predictable color result capableof being consistently and regularly reproduced on a rapid scale to a substantially identical shade, particularly so where the dyeing of such article is to be repeatedly held to a given delicate dark color tone. By deeply impregnating a racket frame as described, its surface color may be permanently maintained without pronolmcedfadingor tendency of being absorbed inwardly into an imd'erlying non-colored core stratum.

- The foregoing is descriptive of a commodity that has been entirely satisfactory in practice as so applied to the manufacture of attractively colored frames, of bent wood, and which specification whenread in connection with the accompanying drawings, is believed to make apparent to those skilled in this art, the advantages afforded by my 66 improvements, it being understood that the more novel features thereof are subject to considerable latitude in execution, all without departing from the spirit and scope of my invention as defined intheappendedclaimsp VI. A laminated wooden frame assembled to include nested plies Mom and the same species of wood that are bent into a common arcuate shapeand glued together into a unitary structure of which certain plies are dye impregnated in distinctive artificial colors prior to the glueing thereof and whereby ply rigidity is augmented with respect to the similar property originally possessed by such undyed woodspecies.

2. A unitary implement of laminated wood comprising nested plies that are similarly bent and glued together into a given arcuate shape, certain of which plies prior to the glueing thereof are respectively impregnated with a water soluble anilin dye throughout their respective body confines in distinctive hues.

3. A unitary impelling implement including a dye impregnated bent frame of wood stock. that is given a hoop shape having its respective terminals disposed in substantial parallelism "to provide for a handle and which frame by the dyeing thereof is rendered somewhat more rigid than the original wood stock prior to the dyeing thereof, and a web strung to span the hoop shaped portion of said frame.

4. An embellished impelling implement. having a frame of laminated wood stock including a pair of plies that are similarly bent and glued together flatwise in nested relation, each such assembled ply prior to the glueing thereof being impregnated with a different soluble synthetic dyestufi to impart distinctive artificial colors throughout the respective plies thereof and which plies by the dyeing thereof are in a comparable dried state augmented in superficial hardness with respect to the same property originally possessed by the wood stock and rendered more resistant to superficial abrasive wear without material injury to the original toughness quality possessed by said stock.

5. An embellished laminated racket frame including a pair of nested wooden slats that. are

, similarly bent and glued flatwise into a hoop shape including a forked crotch region from which the several slat ends extend outwardly into a common handle having an interposed contracted neck region, corresponding exposed edge portions of said pair of slats being respectively dye impregnated in distinctive artificial colors to provide a decorative color trim for said frame, and an ornamental overlay of dyed-wood fixedly superimposed upon the aforesaid corresponding exposed slat edges in the vicinity of said crotch region and which overlay is laminated in matched upstanding edgewise registry along a length portion of such underlying slat edges, said overlay leaving a dye impregnated edge portion of the hoop shape uncovered whereby to enhance the embellishment afiorded by said color trim.

6. A unitary implement including a dyed-wood frame member bent into a hoop shape providing for a crotch region, an inlaid throat piece bonded into said crotch region, and a dyed-wood overlay fixedly associated with said throat piece, said overlay being cross-sectionally laminated radially around a curvature axis of the hoop shape and having the laminations thereof directed in substantial parallelism with such axis.

'7. A unitary ball impeling frame of laminated wood comprising nested plies that are similarly bent and glued together into hoop shape, certain of which wooden plies prior to the glueing thereof are respectively impregnated with soluble synthetic dyestufi in distinctive artificial colors.

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