US2521554A - Method of making paper-covered veneer - Google Patents

Description

Sept 5, w50 R. N. WARE, JR., ETAL 2,521,554

METHOD oF MAKING PAPER COVERED VENEER /lc//Aeo lil Mms, JA!

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Sept7 59 1950 R. N. WARE, JR.,

METHOD OF MAKING PAPER CO Filed July 16, 1947 Patented Sept. 5, 1950 METHOD F MAKING VEN EE Jr., and Reginald Cannon, Tal- Richard N. Ware,

PAPER-COVERED R lulah, La., assignors to Chicago Mill and Lumlier Company, Chicago, Ill., a corporation of Delaware Application July 16, 1947, Serial No. 761,188

3 Claims. (Cl. 154-132) This invention relates to the production of paper covered wood veneer from green, undried, steamed wood and moistened, stretched paper, and specifically deals with a process of making veneer products involving the reeling into rolls of freshly peeled veneer sheets, the steaming of said rolls, the unreeling of the hot steamed rolls into elongated flat ribbons of veneer, andthe covering of the ribbons with adhesive-coated) stretched paper which is fxedly-l united to the wood to hold it in an expanded condition as it is dried.

This application is a continuation in part of our copending application Serial No. 617,244 entitled: Method and Apparatus for Making Paper Covered Veneer, led September 19, 1945, now U. S. Patent 2,425,660 granted August 12, -194'?.

In our aforesaid parent application, Serial No. 617,244, freshly peeled veneer sheets are stapled together to form an endless ribbon and the endless ribbon is then covered with adhesive coated wet stretched paper.

According to the present invention, freshly peeled veneer is wound into relatively tight rolls. These rolls are heated With wet steam to raise their temperature Without drying the wood. -The logs from which the wood is peeled are in a green, undried condition. The hot steamed rolls of veneer are unreeled as needed to form ribbons. The ribbons of each successive roll are stitched together in end to end relation to form a continuousY ribbon. 'I'he continuous ribbon, while still in a hot condition, is advanced between the adhesive-coated faces of wet stretched paper webs. The adhesive on the stretched paper webs is of a type adapted to suiliciently bond the paper to the wood so that relative slippage therebetween cannot occur even before the wood and paper are dried. The bond thus created is sufficiently strong so that the paper Will hold the wood against shrinkage during a subsequent drying operation. At the same time the relatively small degree of shrinkage occurring during the drying operation will not cause a puckering or wrinkling of the paper because it is in a stretched condition and has substantially the same coefficient of shrinkage as the wood that is bonded thereto.

An important feature of the present invention resides in reeling of the freshly peeled veneer sheets so that they can be handled in rolled-up form.

Another feature of the invention resides in the wet steaming of the veneer reel to uniformly heat the wood for producing a hot veneer that will speed up subsequent setting and drying. We have found that certain species of wood, such as Cottonwood, cannot be satisfactorily peeled into veneer sheets from heated logs because the wood bers fuzz up when lathe cut in a hot condition.

According to the present process, the logs are peeled in a cold condition but the freshly peeled veneer is heated.

Another objectpofmthe invention is to provide a processofmaking paper covered veneer which is faster in operation than the process disclosed in our parent application Serial No. 617,244.

Another object of the invention is to provide a method of making paper covered veneer wherein the veneer is steam heated and receiveslthe paper coverings while it is in a hot condition for speeding up the drying of the adhesive.

A still further object of the invention is to provide a continuous process of making a veneer product wherein freshly peeled veneer sheets are wound into rolls if relatively long, or are stitched together if relatively short, and are eventually formed into a continuous ribbon.

Other and further objects of this invention will be 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, illustrate one embodiment of the invention.

On the drawings:

Figure 1 is a fragmentary broken diagrammatic side elevational view of the first portion of the apparatus used for the method of this invention for forming rolls of veneer for steaming the wound veneer rolls, and for unreeling the wound steamed rolls.

Figure 2 is a view similar to Figure 1 but illustrating a successive portion of the apparatus including the structure for covering the wood veneer with paper.

Figure 3 is a view similar to Figures 1 and 2 but illustrating the third or last portion of the apparatus which serves to dry the paper covered veneer product.

Figure 4 is a plan view of a veneer sheet, onehalf of which is covered with paper in accordance with this invention, and illustrating the manner in which the paper holds the wood against shrinkage.

Figure 5 is a cross-sectional view taken along the line V-V of Figure 4.

Figure 6 is an elevational view of a .wound roll of veneer on a shaft equipped with end wheels or guide rollers for riding on the rails of the apparatus of Figure 1.

Figure '7 is a transverse cross-sectional view taken along the line VII-VII of Figure 6.

Figure 8 is a somewhat diagrammatic crosssectional view taken either along the line VIII- VIII of Figure 1, or the line VIII-VIII of Figure 2 and showing the stitching machines used in the apparatus.

Figure 9 is a fragmentary plan view showing adjoining stitched-together veneer sheets.

As shown on the drawings:

As shown in Figure l, the reference numeral I designates generally a log-peeling lathe commonly used for cutting veneers from wooden logs. The lathe I0 includes a driven log supportl II and a cutting blade I2. The sipport II drives a log I3 in the direction of the arrow against the blade I2 and a veneer ribbon I4 is peeled or cut from the log. In accordance with this invention a reeling stand I5 is mounted adjacent the lathe I0 and drlvingly supports a shaft I6 on which the veneer I4 is reeled to form a roll I1.

Uprights I8 carry three superimposed pairs of tracks or rails I9 to provide a roll-handling stand in front of the reel I5.

The axles or shafts I6 for the rolls I1, as best shown in Figure 6, have flanged rollers Ilia on the ends thereof for riding on the tracks I9. The flanges overlie the outsides of the tracks I9 to hold the rolls between the rails.

The reeling stand I5 is adapted to raise a wound roll I1 to the two upper tracks I9 for depositing rolls I1 on these tracks. The rolls are advanced along the stand 20 to a steam chest 2I having inlet doors 22 adapted to be opened to permit entry of the rolls I1 while still supported on the tracks I9. A plurality of rolls are accommodated at the same time in the steam chest 2 I. A steam inlet pipe 23 supplies wet steam at about 4 to '75 lbs. per square inch pressure to the steam chest 2I for saturating the chest. Wet steam circulates all Aaround the rolls I1 in the steam chest and heats these rolls with'out drying the veneer. The length of the heat treatment will vary, depending upon the thickness of the veneer and the size of the rolls. It is preferred thatthe rolls do not exceed 30 inches in diameter and that they be wound tight enough so as to be evenly disposed around the shaft. Under such conditions the steam treatment may vary from 30 minutes to two hours. The temperature of the steam is preferably maintained around 225 to 240 F. The wood becomes heated to less than the temperature of the steam or to about 160 to 225 F.

After the steaming treatment, the shaft rollers I6a are advanced on the rails I9 to carry the wound rolls I1 out through exit doors 24 of the steam chest.

The top rails I9 have spring-pressed or counterweighted end sections 25 pivoted thereon and adapted to mate with a reel support 26 at the end of the reel section 20. A spring 21 or counterweight normally holds the pivoted sections 25 ln a raised position to open up a gap 28 between the reel support 26 and the rail section 25. When a roller I6a rides up to the rail sections 25, the weight of the roll I1 will depress the springs or counterweights so that the sections 25 will mate with the reel support 26 and the roll I1 is thereby fed to an unreeling stand designated generally by the numeral 29.

The rails I9 beneath the top rails terminate in pivoted end sections 30 pulled upwardly to the inclined position of Figure 1 by springs such as 3l or counterweights (not shown). When rollers carrying rolls I1 are advanced on the rails I9 to the pivoted sections 30, these sections 30 will be depressed to mate with extension rails 32 of a second unreeling stand 33 and the roll I1 will be deposited into this unreeling stand without lifting it off of the rails.

The unreeling stand 29 has inclined extension rails 34 extending downwardly from the rails 26 thereof to spring-pressed or counterweighted pivoted sections 35 held by springs 36 or counterweights (not shown) above the rails 32. When the roll I1 is unwound from a shaft and its rollers in the unreeling stand 29 the rollers can carry the shaft down the inclined rails 34' to the springloaded or counterweighted rails 35 whereupon the weight of the shaft will depress these rails into registration with an inclined set of rails 31 communicating at their lower ends with the bottom rails I9. When a roll I1 in the unreeling stand 33 is completely unwound from its shaft, the rollers on this shaft will be guided back along the rails 32 to the inclined rails 3`I without interference because the rail sections 30 and 35 will be raised by the springs 3I and 36 to an out of the way position as shown in Figure 1. The shafts I6 are thereby returned along the bottom set of rails I9 to the winding reel stand I5. The two top sets of rails I9 are preferably inclined downwardly toward the reel stands 29 and 33 while the bottom set of rails I9 is preferably inclined downwardly toward the winding reel stand I5 so that the wound rolls I`I will gravitate toward the unreeiing stands 29 and 33 while the shafts I6 will gravitate toward the reeling stand I5.

, Beneath the bottom rails I9 there is provided a conveyor system for handling short pieces of veneer which are not wound into rolls I1. As shown in Figure 1, an inclined conveyor 38 of the belt or tape type extends from under the lathe knife I2 to a horizontal conveyor 39 beneath the bottom rails I9. This conveyor-39 feeds through a clipper 39a which trims the edges of the veneer pieces to form straight ends. The conveyor 39 discharges .into a sewing machine 40. As shown in Figure 8, the sewing machine 40 has a head 4I carrying a plurality of needles 42 at spaced intervals across the width of a veneer sheet I4 fed therethrough. As illustrated in Figure 9, pieces of veneer I4 are stitched together by rows of stitches 43 spaced at intervals across their width. The stitched pieces of veneer I4 can fall by gravity out of the machine 40 to be picked up by an inclined conveyor 44 which raises them to an elongated horizontal conveyor 45. The horizontal conveyor extends to another horizontal conveyor 46 beyond the unreeling stand 29. Alternately, as shown in dotted lines, the stitched together pieces of veneer from the conveyor 44 can be wound into a roll on a reeling stand a and moved up to the rails I9 for a steam treatment in chest 2|.

A conveyor 41 is provided to receive veneer unwound from a roll I1 on the unreeling stand 29 to convey this veneer to the conveyor 4B. Another conveyor 48 is provided to convey veneer unwound from' a roll on the unreeling stand 33 to the conveyor 46. Therefore, all veneer sheets are eventually fed to the conveyor 46.

-The conveyor 45, as indicated above, receives stitched together short veneer pieces. These stitched-together pieces eventually form a ribbon of appreciable length that can be selectively fed to the conveyor 46 for attachment to the trailing end of a veneer sheet I4 from an unwound roll I1, if desired.

As shown in Figure 2, a second sewing machine 49 similar to the machine 40 of Figure 1 receives the veneer I4 from the conveyor 46 and stitches f the various veneer sheets together to form a continuous ribbon irrespective of whether or not these sheets come from a roll I1 or from the conveyor 45. The continuous ribbon is fed to an inclined conveyor 50 onto a horizontal conveyor 5I.

The continuous ribbon of veneer I 4 on the conveyor 5| is next fed between adhesive coated faces of paper webs in a wet stretched condition. The paper webs are preferably composed of tough kraft paper. l

As shown in Figure 2, a roll of paper 52 is mounted above the apparatus for covering the top face of the veneer ribbon. A paper web W from this roll is guided under a guide roll 53 to a wetting roll 54 contacting the under face of the web and rotatably mounted in a suitable coating pan 55. The pan preferably contains water at temperatures around 180 F. Alternately, the pan can contain a water em'ulsion of a paraffin wax capable of imparting a smooth wax finish on the paper while at the same time having the water thereof penetrate into the paper for wetting it. The wet paper web then passes under a guide roll 56 and is fed to a coating machine having a fountain roll 51 applying -a coating of adhesive to the top face of the web opposite the face engaged by the wetting roll 54. The adhesive is of a type capable of creating a firm bond before it is thoroughly dried so that no slippage will occur between the paper and wood as the wood begins to shrink during a drying operation. A vegetable protein glue is suitable.

After receiving the adhesive coating, the web is directed over a guide roll 58 and around a turning roll 59 so that its adhesive-coated face will overlie the top face of the veneer ribbon discharged off of the conveyor 5|.

A second roll of paper 60 is mounted beneath the apparatus and feeds a second web W over guide rolls 6I to a turning roll 62 for providing a reverse run of the web over a wetting roll C3 operating in a pan 64 to Wet the web with hot water or with a water-wax emulsion as described in connection with the web from the roll 52. The web from the wetting roll 63 then passes around another turning roll 65 to again have its direcn tion of travel reversed. Guide rolls 66 direct the web to aI coating apparatus 61 which applies the same type of adhesive to the opposite face of the web as is applied to the other web by the coating apparatus 51. The adhesive-coated web is then passed under a guide roll 68 and around a turning roll 69 which directs the adhesivecoated face of the web under the ribbon of veneer I4 discharged from the conveyor 5i.

It will be noted that the web runs between the wetting rolls and the adhesive coating niachines are appreciably long so that the water can penetrate into the webs and permit them to stretch. The wet webs are placed under tension by the coating machines 51 and 61 so that the Y adhesive is applied to the wet webs in a stretched condition on the faces of the webs opposite the faces engaged by the wetting rolls. The adhesive itself preferably has a water base so that the opposite faces of the webs are also wet with water. The runs of the webs beyond the adhesive coating machines are also of considerable length so that further stretching of the webs is possible. The adhesive-coated faces of the webs are guided by the turning rolls 59 and 69 in spaced relation above and below the veneer ribbon fed from the conveyor 5 i.

The webs with the veneer ribbon therebetween are fed through a first press composed of top and bottom rollers spring loaded toward each g other by a spring such as 1i. The chamber 12 contains a number of press rolls 13 composed of cooperating top and bottom rolls. The bottom rolls only may be driven with a throw in clutch 6 attachment to permit threading of paper covered veneer through the machine. The chamber also contains a'series of driven press rolls 14. Thus. as shown, the last three sets of rolls are positively driven and are spring loaded as at 15 to exert increased pressures on the paper and veneer assembly received therebetween. The press 10 advances the webs and veneer ribbon to the press rolls 14 through the idler rolls 13 and, when the assembly is completely threaded through the rolls 14, the drive on the press 10 is released so that the rolls 14 become the main driving rolls forr pulling the paper and veneer through the idler rolls 13. The rollers coact for ironing the paper webs on the wood ribbon sandwiched therebetween to insure a good i'lrm contact to create a thorough adhesive bond. 'Ihe tension pull established by the rolls 14 keeps the paper webs in stretched condition and the idler rolls 13 maintain somewhat of a dragging action on the paper.

The chamber 12v is heated to temperatures around 120 to 180,F. by a steam coil 16 extending through the chamber. The steam coil heats air in the chamber and the heated air starts to remove some' of the moisture from the webs and veneer without, however, drying the veneer to its shrinking point, which is usually below 30% moisture content. Moisten'ed air is from the chamber by a blower 91.

By the ltime the paper and veneer reach the discharge end of the chamber 12, the adhesive bond between the paper and the wood is suiliciently strong so that the slippage cannot occur when the wood starts to shrink. While the adhesive may not yet be in its iinal set state, it is,

nevertheless, strong enough to hold the wood in its expanded or swollen condition even when the moisture is dried from the wood and the wood tends to shrink. The heated veneer from the steaming operation is soft and pliable and facilitates drying and setting of the adhesive. The adhesive itself can be applied in a heated condition if desired. The paper, of course, is heated from the application of the hot water or wax emulsion. These heat treatments speed up the operation. I

The paper covered wood veneer is deposited on another conveyor 11 as it leaves the chamber 12 and this conveyor feeds a flying shears 18 which cuts the material into the desired length segments. The shears 18 includes a tiltable cutting section 19 rocked by an eccentric 80 so as to move the cutter blades with the advancing material at a correlated speed thereby preventing buckling of the advancing material during the cutting operation.

The cut product is deposited on another conveyor 8 i.

The conveyor 8l, as shown in Fig. 3, discharges to a tipple 82 which selectively supplies superimposed conveyors 83 extending through a drying kiln 84. The kiln 84 is quite long and has a blower 85 mounted on top thereof for receiving air from an inlet duct 86 and discharging the air through a distributor duct B1 to an inlet duct 88 at the discharge end of the kiln. The air and kiln are heated by steam pipes or other heating means (not shown) so that the kiln will have an inlet temperature around 250 and an outlet temperature around 375 F. The circulating hot air in the kiln drives the moisture out of the paper and Wood to produce the final dried product which still contains enough moisture so that it will not warp when exposed to the atmosphere. The conveyors 83 extend beyond the discharge end of the exhausted 7 kiln so that the product can cool down sunlciently to a temperature convenient for handling.

As explained above, the adhesive bond between the paper and the wood is sufficiently strong in a partially set condition so that relative slippage between the paper and. wood will not occur when the wood is dried.

As illustrated in Figures 4 and 5, the product 39 of this invention is composed of a wood veneer core 9|, adhesive bonds 9| on each face of the core, and paper covers 92. The wood core 90 is held in an expanded swollen condition such as it assumes when it is saturated with moisture. Even though the moisture content of the product is reduced materially beneath the shrinking point of the wood, the paper is strong enough to hold the wood against shrinking. This is illustrated in Figure 4, wherein only half of the wood is covered with paper. The exposed half 90a is in a shrunken, dried condition, while the covered half Sl is just as dry, but in its original expanded condition. As illustrated, considerable shrinkage normally occurs upon the drying of the wood veneer, and this shrinkage frequently produces checks and cracks 33 between fiber bundles of the wood. A dried veneer sheet is therefore usually full of checks and holes such asf93. The grain 94 of the wood extends longitudinally or across the width of the veneer ribbon and in the drying of the uncovered veneer the pith or soft wood between the harder ber bundles will tear apart to produce the checks and holes. This condition does not occur in the paper covered portion of the wood, where the grain 94 remains in its expanded condition and the fiber bundles are not allowed to pull the softer pith apart to create open holes or checks.

Some slight shrinkage, in the nature of 1 to 2%, does occur as the green wet wood is dried down to the nished condition wherein its moisture content is about 6 to 12%. This shrinkage takes place without puckering or wrinkling the paper bonded to the wood because the paper is also in a stretched condition and shrinks coextensively with the wood. Any shrinkage of the wood thereby merely permits simultaneous shrinkage of the stretched paper which in no event reaches the stage where the paper becomes compressed to wrinkle or pucker.

. The paper sheets, by being bonded to the green, undried wood in its swollen condition, with a bond that is strong enough to resist relative slippage between the paper and wood even before the wood is dried, will save as much as 10 to 25% of shrinkage loss heretofore attendant with the drying `of wood. 'The undried green wood contains about 120 to 130% moisture by weight, and this moisture content can be reduced to about 30% by weight before shrinkage of the wood begins.

According to this invention, the adhesive bond is sufficiently set before the wood is reduced to a moisture content of 30% to prevent relative slippage between the paper and the wood when the assembly is dried below 30%. The adhesive 'thus has a strong wet strength setting capacity.

From the above descriptions'vit will be understood that the invention provides a rapid process of forming paper covered wood veneer including the reeling of veneer sheets into rolls, the steaming of the rolls to uniformly heat the veneer sheets, the covering of the hot veneer sheets with heated moisture-saturated stretched paper, the bonding of the paper to the veneer sheets before 8 l the veneer is dried to its shrinking point and the final drying of the paper covered product to a moisture content between 6 and 12% where it will not warp in any atmosphere.

It will, of course, be understood that various details of the process may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

We claim as our invention:

1. The method of making paper covered wood veneer which comprises wet steaming a wound wood veneer roll to heat the wood without drying it, unwinding the hot steamed veneer from the wood, advancing the unwound hot steamed veneer between the adhesive coated faces of two sheets of wet stretched kraft paper, pressing the adhesive coated faces of the paper against the hot steamed veneer as it advances, passing the advancing assembly through a heated chamber to partially set the adhesive for forming a nonslipping bond between the wood and paper without drying the wood to its shrinking point, and drying the paper covered veneer to a moisture content between 6% to 12% while the adhesive bond'holds the wood in its expanded swollen wet condition.

2. The method of making paper covered veneer which comprises wet steaming a wood veneer ribbon, wetting one face of each of two webs of paper, stretching said wet webs, applying wet adhesive on the surfaces of said stretched webs, pressing the adhesived surfaces of said webs against opposite sides of said veneer, heating the assembly to bond the paper to the veneer without materially drying the wood, and thereafter drying the assembly to a moisture content below the shrinkage point of the wood while the paper holds the wood against substantial shrinkage.

3. The method of making paper covered veneer which comprises wet steaming a wood veneer ribbon, wetting a face of at least one web of paper, stretching the wet web, applying adhesive to the surface of said stretched web, pressing the adhesived surface of said stretched web against a face of the wet steamed veneer ribbon, heating the assembly to bond the paper to the veneer without materially drying the wood, and thereafter drying the assembly to a moisture content below the shrinkage point of the wood while the paper holds the wood against substantial shrinkage.

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 942,852 Baekeland Dec. 7, 1909 1,369,743 Hood et al Feb. 22, 1921 1,714,859 Elmendorf May 28, 1929 1,805,179 Loetscher May 12, 1931 2,095,389 Kondolf Oct. 12, 1937 2,142,932 Beard Jan. 3, 1939 2,331,297 Bendix Oct. 12, 1943- 2,372,617 Trew Mar. 27, 1945 2,425,660 Ware et al. Aug. l2, 1947 2,442,115 Byers et al. May 25, 1948 2,444,918 Cone July 13, 1948

Claims (1)

1. THE METHOD OF MAKING PAPER COVERED WOOD VENEER WHICH COMPRISES WET STEAMING A WOUND WOOD VENEER ROLL TO HEAT THE WOOD WITHOUT DRYING IT, UNWINDING THE HOT STEAMED VENEER FROM THE WOOD, ADVANCING THE UNWOUND HOT STEAMED VENEER BETWEEN THE ADHESIVE COATED FACE OF TWO SHEETS OF WET STRETCHED KRAFT PAPER, PRESSING THE ADHESIVE COATED FACES OF THE PAPER AGAINST THE HOT STEAMED VENEER AS IT ADVANCES, PASSING THE ADVANCING ASSEMBLY THROUGH A HEATED CHAMBER TO PARTIALLY SET THE ADHESIVE FOR FORMER A NONSLIPPING BOND BETWEEN THE WOOD AND PAPER WITHOUT DRYING THE WOOD TO ITS SHRINKING POINT, AND DRYING THE PAPER COVERED VENEER TO A MOISTURE CONTENT BETWEEN 6% TO 12% WHILE THE ADHESIVE BOND HOLDS THE WOOD IN ITS EXPANDED SWOLLEN WET CONDITION.

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