US2425660A - Method and apparatus for making paper-covered veneer - Google Patents

Description

R. N. WARE, .m, :T m. 2,425,660

IBI'HOD Ann APPARATUS ron mnia rum comm mm Aug. 12, 1947.

mm Sept. 19, 1945 2 Shoots-Shoot 1.

Aug. 12, 1947. 2,425,660

.umaqn AND APPARATUS FOR MAKING PAPER covzann VENEER R. N. WARE, JR, ETAL Filed Sept. 19, 1945 2 Sheets-Sheet 2 Q Q Q Q zzz'ezms Zizcbzzrr/ N Wars [/17 RE zzzFz/d 5122212012 Patented Aug. 12, 1947 METHOD AND APPARATUS FOR MAKING PAPER-COVERED VENEER Richard N. Ware, Jr., and Reginald Cannon, Tallulah, La., assignors to Chicago Mill and, Lumber Company, Chicago, 111., a corporation of Delaware Application September 19, 1945, Serial No. 617,244

8 Claims. 1

This invention relates to the production of paper covered wood veneer from green, undried wood and moistened paper.

Specifically this invention relates to a continuous process and continuously operating apparatus for producing paper covered wood veneer. The process of the invention requires only one drying operation and produces a laminated product free from wrinkles and blisters.

In accordance with this invention, green, undried lumber is peeled from a log by a rotary cutting lathe. Such lumber may contain varying amounts of moisture, depending upon its density, th locality in which it is found, etc. Lumber found in Madison Parish, Louisiana, for example, averages about 130% moisture content. This means that moisture is present in the lumber at the ratio of 130 pounds of water to 100 pounds of dry wood fiber. The veneer is selectively fed to superimposed belts or conveyors. Some of these conveyors supply short lengths of veneers to a trimming machine wher imperfect wood sections are eliminated. The trimmed sheets are then stapled together and are fed backto one of the superimposed conveyors to be used as needed.

The other conveyors supply longer lengths of veneer through a trimming machine where imperfect sections are removed. The veneer pieces are then fed through a stapler to be connected together to form a continuous ribbon. As the pieced-together sheets from the aforementioned conveyor are needed, they can be fed down to the next lower conveyor and are connected to previously fed sheets to form a continuous ribbon. The continuous ribbon is then fed by a conveyor between the adhesive coated facesofpaper sheets. These paper sheets have previously been moistened by wetting rolls and tensioned. The nonmoistened'faces of the paper are then coated with adhesive such as, for example, a soy bean glue in water solution or suspension. Themoistened, adhesive-coated paper sheets are next pressed onto opposite faces of the wood veneer ribbon and are adhesively united to the wood veneer by means of a series of pressure rolls. The moistened glue coated sheets have a moisture content balancing the moisture content of the wood, For example, when the wood has 9. moisture content of 130%, the glue on the paper is regulated to put 120% of moisture into the two paper sheets and the wetting rolls bring the moisture content of the two sheets up'to 130% t balance the moisture content of the wood. The continuous ribbon of paper covered wood veneer is then passed through a clipping machine to be severed into desired lengths. The severed lengths are selectively fed to superimposed conveyors passing through a drieror kiln. The drier or kiln is equipped with a heated air circulating system to dry the paper covered veneer and set the adhesive. The drier is preferably operated at an inlet temperature of 250 F. and an outlet temperature of 350 F. v

The laminated paper covered veneer entering the drier contains about to 106% moisture by weight, and the moisture content of the paper covered veneer is reduced to about 20 to 30% by weight before the paper covered veneer is heated up to F. The paper covered veneer, however, is further dried before leaving the drier to have a moisture content of about from 6 to 12% by weight, thereby equaling the normal humidity conditions of the atmosphere, and preventing warping of the product.

A feature of the invention resides in the provision of a continuous process wherein wood veneer sheets are secured in end to end relation to form a continuous ribbon, and wherein continuous sheets of paper are adhesively united to one .or both faces of the continuous ribbon of veneer.

Another feature of the invention resides in the elimination of heretofore-required pre-drying steps; and the utilization of wet or green wood together with moistened paper to form a' laminated paper covered veneer with only one dryin operation for both the wood and the'paper.

A further feature of the invention resides in the moistenlng of paper prior to its application to the wood for eliminating formation of bulges and wrinkles in the paper when the wood shrinks upon drying. The moistened paper is expanded and shrinks with the wood so that the product has smooth, flat paper faces.

An object of the invention is to provide a continuous process of producing paper covered veneer.

A further object of the invention is to provide a process of covering wood veneer with paper which process requires only a single drying operation and utilizes undried wood.

Another object ofthe invention is to provide a continuous process of making paper covered veneer wherein wood veneer sheets are secured in end to end relation to form a continuous ribbon and are then covered with moistened, adhesivecoated paper. subjected to pressure treatment to form a laminated assembly, then cut into desired lengths, and next dried to form a smooth faced product.

A further object of the invention is to eliminate the formation of wrinkles, blisters and bulges on paper covered veneer by creating, in the paper, moisture conditions simulating those in the wood so that the paper and wood will simultaneously shrink upon being dried.

A further object of the invention is to provide apparatus for forming paper covered veneer in a continuous manner.

A further object of the invention is to provide apparatus for forming paper covered wood sheets, which apparatus produces a continuous ribbon of wood veneer, covers one or both faces of the continuous ribbon with paper, severs the paper vcovered ribbon into the desired lengths, and dries the lengths.

Other and further objects of the invention will become apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings which, by way of a preferred example only, illustrates one type of apparatus according to this invention, for carrying out the process of this invention, and further illustrates the product of this process and apparatus compared with prior known products.

On the drawings:

Figure 1 is a fragmentary broken diagrammatic side elevational view of the first portion of the apparatus of this invention which portion produces a continuous wood veneer ribbon.

Figure 2 is a view similar to Figure 1 but illustrating the second portion of the apparatus which portion covers the wood veneer ribbon with moistened adhesive coated paper and presses the paper onto the ribbon.

Figure 3 is a view similar to Figures 1 and 2 but illustrating the third or last portion of the apparatus which portion severs the paper covered veneer ribbon into sheets of the desired lengths and dries the sheets.

Figure 4 is a plan view, with parts broken away to illustrate the underlying wood,-oi' a heretofore known paper covered wood veneer sheet.

Figure 5 is a side elevational view taken along the line V-V of Figure 4.

Figure 6 is a view similar to Figure 4 but illustrating the product of this invention.

Figure '7 is a side elevational view taken along the line VII-VII of Figure 6.

As shown on the drawings:

In Figure 1 the reference numeral Ill designates a rotary log peeling lathe commonly used in cutting veneers. The lathe IO includes a rotating driving support H and a blade l2. A log I3 is mounted on the support I I to be driven in the direction shown by th; arrow and the blade I 2 cuts a veneer sheet l4 from the log l3. A conveyor ii in the formof an endless belt trained around rollers feeds the veneer sheet H to a 4 slide down aninclined guide 21 onto the conveyor 23.

- The third conveyor I9 is driven in a direction opposite to the direction of the conveyors I1 and II for a purpose to be more fully described.

The top three conveyors 26, 2| and 22 supply veneer sheets to an inclined conveyor 28. Guides 29 and 36 respectively guide the veneer from the conveyors 22 and 2| to the conveyor 26. A conveyor 3| receives the veneers from the conveyor 23 to direct the same through a cutter 32. A stapler 33 secures the cut veneers together into a continuous ribbon and this ribbon is allowed to drop onto a conveyor 34 feeding the conveyor i9.

In operation, short veneers or imperfect veneers are fed to the top conveyors 26, 2i and 22 for being trimmed and united into a longer ribbon of veneer. This longer ribbon of veneer is fed, as needed, by the conveyor l3 to the conveyor I! where it is joined with a ribbon on the tipple l6 which as illustrated can be tilted to selectively feed the veneer to any one of six superimposed conveyors l1, l3, I3, 26, 2| and 22. These conveyors are in the form of greatly elongated belts trained around rollers and receiving the veneers on the upper runs thereof. The bottom conveyor l1 supplies the veneer thereon to a conveyor 23 feeding a cutter or trimmer 24 which cuts out imperfect veneer sections and supplies a stapling machine 26 with trimmed veneer sheets. The trimmed sheets are united by the stapler 25 to form a continuous ribbon of wood veneer which is received on a conveyor 26.

The second conveyor II also supplies the conveyor 23 and the veneer from the conveyor 13 can conveyor 23 to form a continuous ribbon. The superimposed conveyors I! to 22 can thus be operated to store veneer sheets until needed while the upper trimmer and staplers 32 and 33 are utilized to supply longer ribbons for connecting with ribbons passing through the lower trimmer and staplers 24 and 25. A continuous ribbon of wood veneer is thus received by the conveyor 26.

The conveyor 26 supplies the continuous veneer ribbon to an inclined conveyor 36 which, as shown in Figure 2, feeds a horizontal conveyor 36.

The second section of the machine shown in Figure 2 is for the purpose of covering the veneer ribbon with adhesive coated moistened paper and for pressing the paper .onto both faces of the ribbon.

As shown in Figure 2, a roll of paper 31 supplies the web W over a fountain roll 33 rotatably mounted in a tank 33 containing a pond P of water. A heating coil 46 heats the water to keep its temperature around F. The fountain roll 38 picks up a film of water from the pond P and deposits the film onto the under-face of the web thereby moistening the web. Tension rolls 4] and 42 are provided on opposite sides of the fountain roll 33 to hold the web in a taut condition as it passes around a portion of the periphery of the roll 38. The moistened web is then directed over a guide roll 43 and under another guide roll 44 to pass under a driven coating roll 45. The coating roll is positively driven in the direction shown by the arrow and supplies a flowable liquid adhesive from a trough T in amounts determined by an inkin roller 46, to the top face of the moistened web. The film of coating material is regulated by pressure in the nip between the coating roll and inking roll. The coating roll 45 pulls and stretches the wet web. The coated paper is then trained around a tu 'ing roll 41 to pass over the top of the veneer rib n from the conveyor 36 and presents its coated face to the veneer.

As shown in dotted lines a second roll of paper 31' is provided adjacent the roll 3'! to supply the fountain roll 33 when the roll 31 is exhausted. The leading edge of the new roll is secured to the trailing edge of the exhausted roll so that the continuous process will not be interrupted.

A second roll of paper 461s rotatably supported 0 at a level beneath the veneer fed by the conveyor 36. This second roll supplies a web W over a guide roll 43 to a turning roll 66 which reverses the direction of travel of the web and feeds the web over a second fountain roll 6| rotating in a pond P of water contained in a tank 52 and heated by means of a heating coil 53 in the same manner described above. A tension roll 54 cooperates with the roll 49 but on the opposite side of the fountain roll 5| to hold the paper in a taut condition as it passes around the fountain roll 5|. The moistened paper travels around guide rolls 55 and 56, under a guide roll 51 and over another guide roll 58 to a positively driven coating roll 59 which is rotated in the direction shown by the arrows topull and stretch the water wet web. An inking roll 80 cooperates with the coating roll 59 to hold a trough T of the same coating material maintained in the trough T. A film of coating material is deposited on the coating roll 59 and transferred to the under face of the moistened web W. The coated web W then passes around a turning roll SI and is directed under the veneer ribbon fed by the conveyor 39.

The water added to the webs W and W by the moistening rolls and by the glue is regulated to balance the moisture content of the veneer. Thus if the woodhas a moisture content of 130 pounds of water per 100 pounds of dry fiber the two wet glue coatedwebs W and W will have a water content'of l30'pounds of water per 100 pounds of dry fibers in the two webs or 65 pounds of water per 100 pounds of dry fiber in each web W or W'." If the wood is covered with one web only, then the water content of this single web should balance the water content of the wood.

The coated faces of the two moistened webs W and W" are pressed onto the opposite top and bottom faces 1 of the veneer ribbon I4 as the assembly'passes between the first pair of squeeze rolls 62. The paper covered veneer then passes between as'eries of press rolls 63. These press rolls are of smaller diameter than the first press rolls 62 and are preferably set so as to exert increasing pressures on the laminated assembly. After passing between the last pair of small diameter press rolls, the assembly then passes between three pairs of positively driven larger diameter press rolls 64 as shown in Figures 2 and 3. These press rolls 64 and the coating rolls 5 and 59 are the only positively driven rolls in the second section of the apparatus and serve to feed the paper to the wood veneer ribbon as well as to pull the paper covered assembly through the presses.

An auxiliary roll of paper 48' is provided adjacent the roll 48 to supply paper to the fountain roll 5| when the roll 48 is exhausted and thereby maintains continuous operation for the apparatus.

The paper coated assembly from the last press roll, is fed through a cutter 65 as shown in Figure 3 to be cut into sheets of the desired length, and these sheets are deposited on a tipple 65 which selectively supplies four superimposed conveyors 61, 68, 69 and I0. These conveyors extend through a drier or kiln 1| and have runs of appreciable length in advance of the inlet of the kiln as well as extending beyond the outlet of the kiln. A blower 12 is mounted on top of the kiln 1| and has an inlet duct 13 communicating with the inlet end of the kiln. H A duct 14 extends along the top of the kiln from the outlet of the blower 12 and supplies a feed duct 15 communicating with the kiln near the outlet end thereof. The air and kiln are heated by steampipes or the'like (not shown) so that an inlet temperature of around 250 F. and an outlettemperature around 350 F. is maintained. The circulating airand heat in the kiln drives the moisture out Of the paper and wood to produce a dried product containing-enough moisture so that it will not warp when exposed to the atmosphere. The length of the run of the conveyor beyond the outlet end of the kiln is sufficient so that the product will cool down to a temperature convenient for handling. The product is removed from the conveyors and stacked or packaged. No further treatment of the product is necessary.

The entire apparatus is operated to continuously move the material therethrough at the rate of from 20 to 60 linear feet per minute,

As shown in Figures 4 and 5 attepts to adhesiveiy unite paper with undried or green veneer has, prior to this invention, resulted in the production of products having wrinkled, blistered and uneven paper covers. In Figures 4 and 5 the reference numerals 16 represent a sheet of wood veneer covered on both broad faces by paper sheets 11. These paper sheets 11 have wrinkles and uneven undulations Ila therein extending transversely across the grain of the wood. These wrinkles are caused by shrinkage of i the wood upon drying. Since green undried lumber shrinks appreciably across the grain thereof when the wood is dried, and since paper secured thereon does not shrink to the same extent, the shrinkage of the wood willpucker and wrinklethe paper as shown.

The product of this invention, on the other hand, has smooth, unwrinkled paper faces as shown in Figures 6 and 7 wherein the reference numerals 1B designate the wood veneer sheet and the reference numerals l9 designate the paper covers on the veneer sheet. The moistening of the paper according to this invention causes the same to expand. The expanded paper is adhesively united, in its expanded condition, to the green undried wood. When the wood veneer is dried, the moistened paper is also dried and shrinks at the same rate as the wood. The grain of the wood extends substantially transversely across the width of the veneer ribbon. The paper on the other hand preferably has the fibers extending longitudinally along the length of the sheet of paper. These fibers tend to expand when moistened and shrink when dried. Since the wood, when moistened, expands mainly across the grain thereof, cross-grain shrinkage of the wood is about the same as along-the-grain shrinkage of the paper. A smooth paper faced product is thus produced.

From the above description it shall be understood that this invention provides a continuous process of making paper faced wood veneer wherein wood veneer sheets are cut from green undried logs and are united in end to end relation to form a continuous veneer ribbon. The veneer ribbon is covered on one or both faces with expanded moistened paper having the grain thereof in substantially right angular relation to the grain of the veneer ribbon. The paper is moistened on the face thereof that is to form the outer surface of the product. The moistened paper is held taut and expands or stretches before being contacted with the veneer ribbon. The other face of the paper is coated, immediately prior to being contacted with the veneer ribbon, with a water solution or suspension of an adhesive that sets on drying. A soy bean glue adhesive is especially satisfactory. The water content of the paper is regulated to balance the water content of the wood. Thus if two sheets of paper are used, to cover opposite faces of the wood, each sheet will have one-half the moisture content of the wood while if one sheet is used to cover only one face of the veneer, this sheet will have substantially the same moisture content as the wood. The adhesive coated face of the paper is pressed onto one or both faces of the veneer ribbon, the paper covered veneer ribbon is cut into segments of the desired length, and the segments are dried to simultaneously dry the paper and wood thereby causing the same to shrink uniformly and produce a smooth faced paper covered veneer wood product. Only one drying operation is necessary and the entire process is continuous with the material movin along at a rapid rate.

We claim as our invention:

1. The continuous method of forming paper covered veneer which comprises uniting undried green veneer sheets in end to end relation to form a continuous veneer ribbon, wetting one face of a web of pape with heated water, stretching the wet paper, coating the other face of the wet paper with an adhesive, continuously advancing the ribbon of veneer and the coated wet paper, pressing the coated face of the wet paper against a face of the veneer while simultaneously advancing the veneer ribbon and paper, cutting the veneer ribbon with the paper thereon into sheets of the desired lengths, and drying the paper covered sheets to simultaneously dry the wood, the paper and the adhesive for producing paper covered veneer sheets having smooth flat paper surfaces.

2. In the method of making paper covered veneer the steps which comprise forming a continuous ribbon of undried venee wood, wetting a, continuous web of paper with water, stretching the wet paper, coating one face of the wet paper with an adhesive, continuously advancing the ribbon of veneer and the coated wet paper in the same direction, pressing the coated face of the paper against the veneer ribbon, repeating the pressing operation at spaced intervals along the length of travel of the veneer ribbon and paper until the paper is adhesively united to the veneer ribbon, and drying the paper covered veneer to simultaneously drive out moisture from the paper, wood, and adhesive and thereby cause the wood and paper to shrink at the same rate for producing a smooth paper face on the veneer.

3. In the continuous method of forming paper covered veneer wood the steps which comprise peeling a green undried log to cut veneer sheets therefrom, conveying the veneer sheets selectively to superimposed conveyors, depositing the shorter veneer sheets on the upper conveyors, trimming defective areas from the short veneer sheets, joining the trimmed short veneer sheets into an elongated ribbon, depositing the longer veneer sheets from the log on the lower conveyors, trimming defective areas from the longer veneer sheets, securing the trimmed longer sheets together to form an elongated veneer ribbon, connecting the elongated veneer ribbon from the lower conveyors with the connected elongated ribbon from the upper conveyors to form a continuous elongated ibbon, advancing the continuous elongated ribbon in a substantially horizontal plane, unreeling paper sheets from rolls of paper above and below the advancing elongated ribbon, depositing films of heated water on one face only of each unreeled web of paper, pulling the paper over coating rolls to stretch and expand the wet paper, depositing a film of adhesive from the coat ing rolls onto the face of the paper opposite the wet face, pressing the adhesive coated faces of the paper against the top and bottom faces of the veneer ribbon, simultaneously advancing the pressed together paper and veneer ribbon, sub- Jecting the paper and veneer ribbon to a series of spaced pressing operations at room temperatures to adhesively unite the paper to the veneer ribbon, passing the paper covered veneer ribbon through a heating tunnel, circulating heated air through the heating tunnel to maintain a tunnel inlet temperature around 250 F. and a tunnel outlet temperature around 350 F., and drying the paper covered venee in said heating tunnel from an initial moisture content of about to 106% moisture to-a moisture content of around 6 to 12% to thereby produce paper covered veneer having smooth flat paper faces.

4. Apparatus for continuously producing paper covered veneer which comprises a rotary veneer cutter, a tipple receiving veneer from said cutter, a plurality of superimposed conveyors receiving veneer from said tipple, superimposed cutting machines at the ends of said conveyors, superimposed stapling machines adjacent said cutting machines, a conveyor for transferring veneer from the upper tiers of said superimposed conveyors through the top cutter and stapling machines, a conveyor for transferring veneer from the upper stapling machine to a lower conveyor, a conveyor for transferring veneers from the lower tiers of said superimposed conveyors through the lower cutter and stapling machines, a series of driven press rolls spaced 1ongitudinally from the lower stapling machine to pull the veneer ribbon along a horizontal plane, means for supporting rolls of paper above and below the veneer ribbon, machines for wetting paper from said rolls, coating machines for coating said paper, guide rolls for directing the coated paper into contact with the top and bottom faces of the veneer, a plurality of press rolls in advance of said positively driven press rolls, and a drier tunnel receiving paper-covered veneer from said press rolls.

5. The method of making paper covered veneer which comprises forming a ribbon of undried green wood veneer, wetting two webs of paper with water, stretching the wet webs, coating one face of each of the two wet paper webs with a wet glue, regulating the Water content of each coated wet web to produce in the two webs a total moisture content substantially equaling the moisture content of the wood veneer ribbon, depositing the coated faces of the wet paper webs on opposite faces of the wood veneer ribbon, pressing the paper webs against said faces, and drying the resulting laminated assembly.

6. A method of making paper covered veneer which comprises forming a ribbon of undried wood veneer, wetting one face of each of two webs of paper, coating with a wet glue the faces of said webs opposite the wet faces thereof, stretching the wet Webs, depositing the glue coated faces of the wet webs on opposite faces of said wood veneer ribbon, pressing the webs against the veneer ribbon, and simultaneously drying the wood, the paper, and the adhesive to thereby cause the wood and paper to shrink simultaneously and produce a laminated paper covered wood veneer with smooth paper faces.

'7. The method of making paper covered veneer which comprises forming a ribbon of wet veneer wood, wetting one face of a web of paper with water, coating the other face of the paper with a water containing glue, stretching the wet paper, continuously advancing the ribbon of veneer and the coated wet paper in the same direction, pressing the coated face of the paper against the veneer ribbon, and drying the paper covered veneer to simultaneously drive out moisture from the paper, the wood, and the adhesive to thereby cause the wood and paper to shrink at the same rate for producing a smooth paper face on the veneer.

8. Apparatus for continuously forming paper covered veneer which comprises cutting machinery for forming a veneer ribbon from logs, apparatus for uniting succeeding veneer ribbons in end to end relation to form a continuous ribbon, a series of ribbon press rolls arranged for pulling the veneer ribbon therebetween along a horizontal plane, means for supporting rolls of paper above and below the veneer ribbon, machines for wetting one face of each sheet of paper from said rolls of paper, coating machines for coating the other face of each sheet of paper, means for stretching the wet sheets of paper, guide rolls for directing the coated wet stretched paper into contact with the top and bottom faces of the veneer smooth fiat paper surfaces.

RICHARD N. WARE, JR. REGINALD CANNON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,369,743 Hood et a1 Feb. 22, 1921 2,343,740 Birmingham Mar. '7, 1944 2,372,617 Trew Mar. 2'1, 1945 2,150,658 Osgood Mar. 14, 1939 2,095,389 Kondolf Oct. 12, 1937 1,689,812 Wood Oct. 30, 1928

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