US2790483A - Machine and method for the edgegluing of strip stock - Google Patents

Description

A. F. EDERER ETAL April 30, 1957 2,790,483

7 MACHINE AND METHOD FOR THE EDGE-GLUING OF STRIP STOCK Filed June 25, 1954 4 Sheets-Sheet l INVENTORS Arthur E Ederer y Bernard A. Pearson April 30, 1957 A. F. EDERER ETAL MACHINE AND METHOD FOR THE. EDGE-GLUING 0F STRIP s'rocx Filed June 25, 1954 4 Sheets-sheaf. 2

INVENTORS Arthur F. Ederer Bernord A. P arson April 30, 1957 A. F. EDERER ETAL ACHINE AND METHOD FOR THE EDGE-GLUING OF STRIP STOCK 4 Sheets-Sheet 3 Filed June 25, 1954 n Mm wV T8 e mE V v NF A I rd mw r I A 2y Ber April 30, 1957 A. F. EDERER ET AL 2,790,483

MACHINE AND METHOD FOR THE EDGE-GLUING OF STRIP STOCK Filed June 25, 1954 4 Sheets-Sheet 4 veneer- INVENTORS Arthur E Ederer y Bernard A. Pearson v-M MACHINE AND METHOD FOR THE EDGE- GLUING F STRIP STOCK Arthur F. Ederer and Bernard A. PearsomSeattie, Wash, assignors to Ederer Engineering Co., Seattie, Wasln, a corporation of Washington Application June 25, 1954,-Serial No. 43?,406 20 Claims. (Cl; 154-42) This invention relates to'a machine and method for the edge-gluing of strip stock. Finding perhaps its greatest usefulness in the plywood industry, the present invention is especially advantageous as a means of producing wide strips of face veneer, relatively free of imperfections, from selected multiple narrow strips which have been so cut from the elongated ribbon taken from a peeler leg as to remove pitch pockets, knots, checks, cracks and other blemishes. These imperfections are perforce objectionable in veneer which is to be exposed to view. Within the plywood industry, by reason of the unusually low cost at which veneers can be edge glued with the present machine and method, the present teachings further lend themselves to the production of wide or long panels of veneer for core or cross banding usage. In allied fields, suggested uses to which the machine and method of our invention may be put are the edge gluing of thin hard board, core board, glass fiber laminates, paper laminates, container board and the like. In order to simplify and at the same time give utmost clarity to the following description and claims, the material being worked will be referred to throughout as Wood veneer but this term is to be interpreted liberally'as comprehending Within its meaning all applicable materials including but in no sense limited to those which we have herein specifically named.

In the more accepted techniques, edge-gluing of strips of wood veneer is performed in one of two ways. One such procedure involves the use of a rotating heated cylindrical drum. A succession of veneer strips having their edges coated with glue edge of a following strip against the trailing edge of a preceding strip, are carried circumferentially of this drum while being drawn tightly against the surface. This systern is exemplified by the Miller Patents Nos. and 2,290,762, issued July 21, 1942. The other method of edge-gluing veneer strips is commonly termed straightline gluing, straight in the sense that the path travelled by the strips in course of being bonded edge-toedge is approximately planar as distinguished from the arcuate path prescribed by a cylindricalplaten. The systems shown in the Bolling Patent No. 2,398,353, issued April 16, 1946, and in the Carlson Patent No. 2,544,133, issued March 6, 1951, are examples of straight-line gluing. Straightine gluing is generally considered to be the more preferred system and the machine and method of the present invention, in its broad aspect, is of this type.

For its general object the present invention aims to provide a machine and method for the edge-gluing of veneer which completely obviates gaps and overlaps along the line of joinder, even with the very-thinnest stock, and I which attains a speed of output far exceeding that which has been considered possible with any of the machines and methods heretofore known. p

it is perforce the object of all edge-gluing machines-to have the abutting glued edges of two adjacent 'stripsex-actly register during the period necessary for the glue to and crowded,- the leading United States Patent V i 2,790,483 P atent ed Apr. 30,

2 set, and this desired result iscomplicated the factlthat the strips, being usually very thin, undulate to a considerable extent, particularly along the edges, These W aVes:

obviously are not uniform, hence the meeting edges of two adjacentstrips are normally out of registration; As

one of its objects the present invention, in. orderto bringthese edges into registration, aims to provide a system giving continuous travel to the strips along a defined generally planar travel path and in course of such travel forcefully" distorting the strips in such a manner as to substitutefor the local variables a constantly changing controlled wave made to conform to an established pattern so that the edges which are to be joined are ,placed and, held; in perfect registration during the period necessary to consummate a secure bondingtherebetween The invention has the still further and important object of devising an endless conveyor for the veneer strips ,ef-

sure whileothers call for cooling. The present inventionmay, if desired, use glues of this nature'butwe prefer to employ a thermo-setting adhesive, examples of which are urea'formaldehyde, resorcinformaldehyde, phenol formaldehyde, plastisols, starches and silicates, and it is a further particular object of the invention to provide a sys-' tern wherein infra red rays serve as the heat medium for setting the glue, and wherein the design'of theconveyor peculiarly lends itself to such heating rays in thatit perniits the infra red rays to operate with a maximum efficiency, the invention, in consequence of its ,use of infrared rays, accomplishing setting of the glue in a considerably shorter time than has been possible with machines and methods heretofore known.

A yet further object of the invention is to provide a system in which there is made to act uponthe conveyed strips in course of their conveyed travel and'following the latters traversal of the heating means acooling inst rumentality' which operates to rapidly dropthe temperature of the glue-bonded strips.

The foregoing, with still additional objects and an,

vantages in view looking especially to the provision of a machine generally more efiicient, one which by comparison with existing machines is considerably less expensive to build, and one which requires for its, operation and maintenance only a minimum-of attention, will appear and be understood in the course of the following-- description and claims, the invention consisting in the.

novel method andin the construction, adaptation and combination of the parts ofa machine for practicing said method hereinafter described and claimed;

In the accompanying drawings;

Figures 1 and2 are fragmentary side elevational-views which, taken together, illustrate a completemachine constructed to embody the preferred teachings of the present invention. The first said view, more especially portrayst the crowder table, which functions -to press the' leading edge of a following veneer strip hard against the trailing edge of a preceding veneer strip, together'with the fore portion of that part of the machine responsibl'e for impressing a-wave pattern into the travelling-veneer strips and at the same time setting the glue bye infrared heat.-

The latter 'saidview portrays theaft portion of said wave heatingpart of the machine together with the cooling table.

.Fig.- 3- is a fragmentary enlarged scale longitudinal-vei'= tical sectional view of 'a -head--endportion ofthe' machinef theview being.- somewhat' schematic in-="that the'irimiwork is largely deleted.

Fig. 4 is a fragmentary longitudinal vertical sectional view of the cooling table, the scale employed corresponding to that of Figs. 1 and 2.

Fig. 5 is a fragmentary transverse vertical sectional view drawn to an enlarged scale on line 55 of Fig. 4.

Fig. 6 is a large-scale schematic view portraying the manner in which successive pressure-exerting rolls are moderately staggered to cause travelling veneer strips to travel a sinusoidal path in moving from the crowding table at one end to the cooling table at the other end of the machine.

Fig. 7 is a fragmentary transverse vertical sectional view drawn to an enlarged scale on line 77 of Fig. 3; and

Fig. 8 'is'a fragmentary transverse vertical sectional view on line 8-8 of Fig. 3.

Reiterating that which has been previously pointed out, veneer strips, being usually very thin, tend to bend or wrinkle in consequence of internal stresses usually attributed to non-uniformity of moisture content and, to a lesser extent, to variations in the graining of the wood. This wrinkling is perforce quite irregular and becomes especially pronounced along those side edges of the strip which run longitudinally of the grain. These are the edges which are bonded together when veneer strips are glued edge-to-edge, but excepting for the Miller machines with their cylindrical platens, and which have a slow speed and hence given an objectionably low output, there has not been heretofore devised any effective continuousoperation machine that will positively bring the meeting edges of two abutting strips into exact registration. Carlson can perhaps be credited with having visualized that,

the edges might be brought into registry if, in lieu of subjecting said edges to the force of a heavy ironing pressure, there is produced throughout the length of the said edges an internal stress having its responsible force of sufficient intensity to override the local stresses. To attain this theoretical end Carlson impresses upon the meeting edges of the veneer a bowed configuration, the bow being a single curve running end to end of the concerned edges. In Carlson the creation of this bend must hence be accomplished very gradually in that such a long bend, to be effective, must have appreciable magnitude, amplitude considered. Moreover, where a long bend of major amplitude is impressed upona veneer strip the impressed wave must be thereafter forcefully erased, all of which means that the output from a machine embodying the teachings of Carlson is little better than that of the Miller machine. The findings of the present invention are that only a simple harmonic wave representing a summation of sinusoids which run longitudinally of the grain, and of only moderate amplitude, need be impressed upon the veneer strip, and that glue coating the meeting edges of two abutting strips can be set in a comparatively short period of time where such edges are subjected to infra red rays.

Clarity in an understanding of the nature of the invention will perhaps be advanced by here stating that the apparatus for practicing the invention comprises, in general, a procession of conveyors onto which veneer strips, having firsthad glue applied to one or both of the side edges thereof, and namely the edges which run longitudinally of the grain, are delivered with said coated edges extending transverse to the path of travel. Such delivered strips are conveyed by the conveyors successively, first traversing a crowding zone wherein, as the word implies, there is performed a crowding action causing the leading edge of each following strip to be pressed hard against the trailing edge of each preceding strip, then traversing a processing zone wherein the crowded strips are subjected to a waving action while being simultaneously brought under the glue-setting influence of infra red rays, and finally traversing a cooling zone wherein the heat of the. glued strips is rapidly dissipated.

Referring to the drawings it will be seen that there is provided a succession of three conveyors which will be hereinafter referred to as the crowder conveyor, the processing conveyor, and the cooling conveyor. The crowder conveyor is composed of complementing upper and lower members comprised, as respects the upper member, of a plurality of laterally spaced endless belts 10 passing about live and idler rollers 11 and 12, respectively, and, as respects the lower member, of a plurality of laterally spaced endless belts 13 passing about live and idler rollers 14 and 15, respectively. The processing conveyor is similarly composed of complementary upper and lower members and each said member is likewise comprised of laterally spaced endless belts, as 16 and 17, but in the instance of the processing conveyor belts the material of which the belts are composed is metal, high carbon steel being suitable, butt-welded to form an endless band, whereas no particular significance is attached to the material composing the belts 10 and 13. Said upper and lower processing belts are each supported by a respective pair of driving and driven shafts, as 2021 and 22-23, and a feature of the invention is that the upper said shafts 20 and 21 admit of being set in vertically adjusted positions, thereby to vary the spacing between the lower run of the upper and the upper run of the lower set of bands. Such lower shafts 22 and 23 have their ends journaled in a stationary lower frame 24. The upper shafts 20 and 21 have their ends journaled in an upper frame 25, and for the purpose of adjusting said upper shafts vertically such upper frame at each of its four corners presents a bearing disc 26 seating upon the lower frame. These discs connect with the upper frame by eccentrics 27 journaled in the frame and'have protruding ends thereof splined or otherwise rigidly connected to regulating arms 28, the free ends of such regulating arms being adjustably secured by knurled nuts 29 to frame-carried quadrants 30. In each side of the upper frame at the tail end thereof there is provided a vertical slot 31, and in each side at the head end there is provided a horizontal slot 32. Pins 33 and 34, respectively, which are carried by the lower frame lodge in these slots. Slots 31 and pins 33 perforce serve as guides holding the tail end of the upper frame to movement in a fixed vertical plane, with expansion and contraction of the frame being compensated by the horizontal nature of the head slots 32. It will be understood that the purpose in varying the spacing between the complementing runs of said two sets of processing bands is to accommodate the machine to different thicknesses of the veneer stock being run.

As here illustrated the two driving shafts 2i) and 22 lie at the tail end of the processing conveyor while the driven shafts lie at the head end, and provided on each such shafts and keyed, pinned or otherwise rigidly secured thereto are respective sets of wheels, as 35 and 36, there being one such wheel for each end of each metal band. The several Wheels in each set are placed at uniformly spaced intervals, and such wheels are staggered so that those carried by each upper shaft occur in the intervals midway between those carried by each lower shaft. While not illustrated the several wheels 35 are each crowned to resist creeping of the bands in a direction endwise to the axis of rotation of the wheels, and for a similar purpose, adjacent the wheels 36, there are provided fair-lead rollers 38 hearing against opposite sides of each band along the upper run of the upper and along the lower run of the lower set of conveyor belts. Bell-crank levers 49 fulcrumed, as at 41, to the upper frame 25 adjustably carry a weight 42 on one of the two arms thereof. The other arm carries a roller 43 which is pressed by said weight against the respective band 16 for tensioning the latter, and at opposite sides of this tensioning roller are yoke arms 44 giving support to the fair-lead rollers. Much the same fair-lead and tensioning arrangement is provided for the bottom bands 13 excepting that in this instance a plain lever 45 is employed so that force of 6 gravity acting upon the weight 46 urges the tensioning roller 47 in an upward direction. I

Journal-mounted by their ends in said upper frame to bear from above upon the lower runs of the upper bands 16 are sets of longitudinally spaced apart transversely extending pressure rolls and longitudinally spaced counterparts of these transverse rolls, denoted by 51, are journal-mounted by their ends in the lower frame so as to hear from below upon the upper run of the lower bands 17, the placement of such lower pressure rolls being such that the same occur in the intervals midway between the rolls 59. While not here illustrated, journal boxes 52 for these several pressure rolls admit of being adjusted individually relative to the related supporting frames, but no need arises for changing the adiustment thereof after the same have been once set in that the only adjustment thereafter required is that given to the upper frame, causing the rolls 50 to be raised or lowered bodily in unison. To the immediate front of each pressure roll and carried by the upper frame 25 or by the lower frame 24, as the case may be, is a respective tray ofinfrared tubes 53 such, for example, as the Merco tube illustrated and described in U. S. Pat. #2535168. Each tube has a reflector 54 focusing its produced heat rays onto edge-abutted veneer strips conveyed by the processing conveyor. In each tray there are preferably three of said infrared tubes, each of 4000 watt capacity, and in our machine as it is presently engineered there are ten of these trays, five above and five below the travel path of the conveyed veneer strips, in a processing zone having an overall length of approximately 20 ft. It is desirable that the trays in each row be spaced more or less equidistantly apart and that the trays of the lower series be staggered with respect to the trays of the upper series to have the lower trays occur in the intervals between upper trays.

It is to be particularly noted that all ten trays are required only when the stock being run is unduly thick or when the strips are being conveyed at a very rapid speed. By way of example, We find that only five trays of the infrared tubes need be activated in the edge-gluing of A fir veneer stock travelling at a conveyor speed as high as 28 F. P. M., this being, in the present machine, a ceiling speed dictated by the rapidity at which the glued strips may be fed by hand to the crowder conveyor. While a 28 F. P. M. output of A edge-glued veneer stock is far in excess of the output possible with any previous machine and method of which We are aware, there is presently being developed, for our machine, a mechanized means of feeding the glued stock which we anticipate will enable us to produce edge-glued veneer at a speed appreciably exceeding the present high output figures. Further by way of example, eight of said trays of infrared tubes are found sufficient to set the glue on A" fir veneer moving through the machine at a speed of 20 F. P. M.

It has been our finding that adhesives exposed to the same temperatures as that of our infrared radiation but obtained by convection heating from other sources has a considerably slower curing speed. A probable explanation is that the infrared waves have a peculiar ability to penetrate into and through the wood, which is an insulating material, or it is quite conceivable that the radiant energy of infrared heat activates, in some way peculiar to itself, the chemical setting of the adhesive.

.Before proceeding to describe the parts of the machine which function at complements of said processing. conveyor, let us dwell on one striking accomplishment possible where the adhesive which is used in the edge gluing of veneers is cured or set by the utilization of the radiant energy of infrared light rays. Occurring in consequence of an ability of the rays to penetrate into and through thewood it becomes possible and practical, should any need therefor arise, to inactivate all of the trays either above or below the path travelled by the conveyed strips aysonss of veneer. Many woods which find extensive usage as face'veneers, pine for example, are prone to discolor under heat and light, and particular care in the application of heat must ordinarily be given to materials of this nature when strips thereof are being edge glued. Using infrared radiation as the curing instrumentality permits all of the heat to be directed to one face only of the veneer stock, leaving the other face unexposed yet accomplishing thorough setting of the glue. The exposed face, which perforce would be concealed in use, might conceivably be almost black yet leave the unexposed face completely free of discoloration.

Reverting now to the crowder conveyor, it will be seen that the tail roller 14 thereof lies beyond the head wheels 36 of the processing conveyor, with the upper level of the belts l3 placed to coincide with the upper level of the bands 17. Longitudinal slats 57 supported by crossmembers 58 carried by the lower frame 24 firmly sustain said crowder belts 13, these slats extending substantially the full length of the crowder table excepting for a gap occurring immediately under the head roller 11 of the .upper crowder belts 10. In traversing this gap the lower crowder belts are sustained by an idler roll 6t Said head roller 11 and its complementing tail roller 12 are each carried for bodily vertical movement by a floating frame 61 which is guidably mounted at its inner end from the upper main frame 25 and at each side from the lower main frame 24. Said end guides comprise pins 64 working in vertical slots 65. The travelling speed of the crowder belts is considerably faster than that of the proc essing conveyor, and it is this accelerated speed which performs the function which the name crowder implies, namely that of causing each of a plurality of successively fed strips to be overtaken by a next succeeding strip, and such following strips to have their leading edge pressed hard against the trailing edge of the immediately preceding strip. The floating frame 61 is made fairly heavy to hold the upper belts 10 firmly against veneer strips passing therebelow, thus to insure a positive friction drive, and for adjusting this Weight a yielding upward thrust is exerted by springs 66 against the side guide pins 64.

As regards the cooling conveyor, which extends from the tail end of the processing conveyor so as to receive the multi-strip veneer sheet following traversal by the latter of the processing zone, such is comprised of a plurality of transversely spaced belts 70 passing about live and idler rollers 71-72, respectively. The veneer sheet feeds from the processing conveyor onto the upper run of these belts and by the latter is conveyed between perforated facing plates 73 of two boxes, as 74 and 75, one lying above and the other lying below said belt run. Air for cooling said sheet is delivered under the pressure influence of a blower or blowers (not shown) through ducts 76 to the boxes, issuing through the perforations of the plates ontoupper and lower surfaces of the sheet.

It will be understood, in setting the upper frame 25, that the pressure rolls 5% carried thereby are brought into such relation to the pressure rolls 51 as will cause the veneer strips conveyed by the processing conveyor to traverse a sinusoidal course, and which is to say follow the path of a propagating wave. For thin veneers such, for example, as or ig" the usual setting places the pressure rolls 50 such that a horizontal plane tangent to the bottoms is moderately below a horizontal plane tangent to the tops of the bottom pressure rolls 51. The pressure rolls 5t) are raised somewhat for handling veneer strips of greater thickness. As the successive edgeabutted strips progress along said sinusoidal path, the pressure from the tensioned bands, exerting force upwardly and downwardly alternately, upon'the advancing strips through the span, on the one hand, between two adjacent lower, pressure" rolls and, onthe other hand, -betu'leen' two adjacent upper pressure rolls, im presses upon such; strips a corrugated shape or, more specifically, a traversing simple harmonic wave running transversely from one to the other side edge of the strips. This wave is represented in Fig. 8. The grain of the wood strips runs longitudinally, or approximately longitudinally, of the juxtaposed edges. The produced wave is a summation of sinusoids which runs longitudinally of the grain or, otherwise stated, a harmonic pattern of multiple waves in which the z axes of these individual waves are each at cross angles to the juxtaposed edges. The Wood strips are maintained in such corrugated condition throughout the travel of the strips with the processing conveyor, the time interval thereof being sufficient to substantially set the glue.

For imparting to the processing conveyor and to the cooling conveyor travelling movement of corresponding speed and imparting to the crowder conveyor an accelerated travelling speed there is shown a motor 77 passing the drive through chains '78 and 79 to a sprocket wheel 86 fast to the driving shaft 22. Respective meshed gear wheels 83 and 82 fast to said shaft 22 and to the driving shaft 25) pass the drive from the former to the latter shaft. While not shown, a chain carries the drive from driving shaft 22 to a sprocket wheel fast to the head roller 71 of the cooling conveyor. For powering the live tail roller 14 of the crowder conveyors lower belt 13 a chain 83 passes power to a sprocket wheel 84 from a sprocket wheel 35 on the driven shaft 23. From the live tail roller 14 a chain 86 in turn passes the drive to the live tail roller 11 of the crowder conveyors upper belt 1.9, being tensioned by a spring-pressed idler wheel @7. The motor 7'7 is equipped with a rheostat to adjust its speed so that the time interval required for the veneer strips to negotiate the processing conveyor may be increased and decreased for greater and lesser thicknesses of veneer, or for more and less activated heating trays.

The method of the invention, and the machine for practicing same, are thought to be clear from the foregoing. It will be apparent that modifications may be resorted to without departing from the spirit of the invention and we accordingly intend that no limitations are to be implied and that the hereto annexed claims be given a scope fully commensurate with the broadest interpretation to which the employed language fairly admits.

What we claim, is:

l. The method of edge-joining wood veneer strips having a grain running longitudinally of the edges which are to be joined, and which comprises feeding at least two of said strips one in following relation to the other along a generally planar travel path with the edges which are to be joined having glue applied thereto and with said glued edges extending transverse to the course of travel and juxtaposed the leading edge of the following strip against the trailing edge of the preceding strip, and in course of such travel impressing upon the juxtaposed edges a simple harmonic wave running longitudinally of the grain from one to the other side edge of the strips.

2. The method of edge-joining wood veneer strips having the grain running longitudinally of the edges which are to be joined, and which comprises feeding at least two of said strips one in following relation to the other along a travel path with the edges which are to be joined having glue applied thereto and with said glued edges extending transverse to the course of travel and juxtaposed the leading edge of the following strip against the trailing edge of the preceding strip, and in course of such travel impressing upon the juxtaposed edges a simple harmonic wave running longitudinally of the grain from one to the other side edge of the strips.

3. The method of edge-joining wood veneer strips having the grain running longitudinally of the edges which along a given travel path with the edges which are to be joined having thermosetting glue'applied thereto and with said glued edges extending transverse to the course of travel and juxtaposed the leading edge of the follow ing strip against the trailing edge of the preceding strip, in course of such travel impressing upon the juxtaposed edges 21 simple harmonic wave running longitudinally of the grain from one to the other side edge of the strips, and while maintaining the said simple harmonic wave upon the juxtaposed edges applying heat thereto to set the glue.

4. The method of edge-joining wood veneer strips having the grain running longitudinally of the edges which are to be joined, and which comprises feeding at least two of said strips one in following relation to the other along a generally planar travel path with the edges which are to be joined having thermosetting glue applied thereto and with said glued edges extending transverse to the course of travel and juxtaposed the leading edge of the following strip against the trailing edge of the preceding strip, in course of such travel impressing upon the juxtaposed edges 21 simple harmonic Wave running longitudinally of the grain from one to the other side edge of the strips, and while maintaining the said simple harmonic wave upon the juxtaposed edges setting the glue by infra red radiation.

5. The method of edge-joining wood veneer strips having the grain running longitudinally of the edges which are to be joined, and which comprises feeding at least two of said strips one in following relation to the other along a given travel path with the edges which are to be joined having glue applied thereto and with said glued edges extending transverse to the course of travel and juxtaposed the leading edge of the following strip against the trailing edge of the preceding strip, in

' course of such travel impressing upon the juxtaposed edges a simple harmonic wave running longitudinally of the grain from one to the other side edge of the strips, applying heat to said strips to set the glue While continuing to impress said wave upon the juxtaposed edges, and then cooling the strips by passing the same through a zone of agitated air.

6. The method of edge-joining wood veneer strips having the grain running longitudinally of the edges which are to be joined, and which comprises feeding at least two of said strips one in following relation to the other along a course generally following the line of propagation of a comparatively flat simple harmonic wave with the edges which are to be joined having glue applied thereto and with said glued edges extending transverse to the course travelled by the strips and juxtaposed the leading edge of the following strip against the trailing edge of the preceding strip, and during such travel impressing upon the juxtaposed edges a simple harmonic wave running longitudinally of the grain from one to the other side edge of the strips.

7. The method of edge-joining wood veneer strips having the grain running longitudinally of the edges which are to be joined, and which comprises giving continuous travel to at least two of said strips one in following relation to the other along a course generally following the line of propagation of a comparatively flat simple harmonic wave with the edges which are to be joined having glue applied thereto and with said glued edges extending transverse to the course travelled by the strips and juxtaposed the leading edge of the following strip against the trailing edge of the preceding strip, and during such travel impressing upon the juxtaposed edges a simple harmonic wave running longitudinally of the grain from one to the, other side edge of the strips.

8. The method of edge-joining wood veneer strips, and which comprises first applying thermosetting glue to the edges which are to be joined, and then moving a succession of said veneer strips along a given travel path with.

the glued edges extending transverse to the line of progress and in course of said travel causing each of the strips in turn to be overtaken by the next succeeding strip so as to bring the glued edges into juxtaposition,.and then directing infra red rays onto the strips for setting the glue with the rays substantially encompassing the veneer strips throughout a zone of sufiicient extent, considering the speed at which the strips move, as will assure a setting of the glue upon a traversal of said zone.

9. The method of edge-joining veneer strips recited in claim 8 in which the sources from which rays issue are located both above and below the strips as they move through said zone and are staggered as between the sources of infra red rays which lie above and those which lie below the moving strips.

10. A machine for edge-gluing wood veneer strips each of which has its grain running longitudinally of the edges which are to be joined, comprising a generally horizontal processing throat defined at the top by the lower run of an upper endless conveyor belt and at the bottom by the upper run of a lower endless conveyor belt, each of said belts comprising a multiplicity of parallel uniformly spaced tensioned bands and with the bands of the one conveyor occurring in the intervals midway between the bands of the other conveyor, and a respective row of transversely extending longitudinally spaced apart pressure rolls bearing from below upon said upper run of the lower conveyor and from above upon the lower run of the upper conveyor and characterized in that the rolls of the lower said row occur in the intervals between the rolls of the upper said row, the two rows of rollers being so placed, one relative to the other, as to prescribe a sinusoidal path for veneer strips conveyed by said conveyor belts through said processing throat.

11. A machine for edge-gluing wood veneer strips each of which has its grain running longitudinally of the edges which are to be joined, comprising a generally horizontal processing throat defined at the top by the lower run of an upper endless conveyor belt and at the bottom by the upper run of a lower endless conveyor belt, each of said belts comprising a multiplicity of parallel uniformly spaced tensioned bands and with the bands of the one conveyor occurring in the intervals midway between the bands of the other conveyor, a respective row of transversely extending longitudinally spaced apart pressure rolls bearing from below upon said upper run of the lower conveyor and from above upon the lower run of the upper conveyor and characterized in that the rolls of the lower said row occur in the intervals between the rolls of the upper said row, the two rows of rollers being so placed, one relative to the other, as to prescribe a sinusoidal path for veneer strips conveyed by said conveyor belts through said processing throat, and means concentrating heat upon the veneer strips conveyed by said conveyor belts through said processing throat.

12. A machine for edge-gluing wood veneer strips each of which has its grain running longitudinally of the edges which are to be joined, comprising a generally horizontal processing throat defined at the top by the lower run of an upper endless conveyor belt and at the bottom by the upper run of a lower endless conveyor belt, each of said belts comprising a multiplicity of parallel uniformly spaced tensioned bands and with the bands of the one conveyor occurring in the intervals midway between the bands of the other conveyor, a respective row of transversely extending longitudinally spaced apart pressure rolls hearing from below upon said upper run of the lower conveyor and, from above upon the lower run of the upper conveyor and characterized in that the rolls of the lower said row occur in the intervals between the rolls of the upper said row, the two rows of rollers being so placed, one relative to the other, as to prescribe a sinusoidal path for veneer strips conveyed by said conveyor belts through said processing throat, and means directing infrared rays upon the veneer strips conveyed by said conveyor belts through said processing throat.

13. The machine of claim 12 in which the means for directing infrared rays comprises multiple reflector backed' trays of infrared heating units "located at spaced intervals 14. A machine according to claim 13 in which the trays,

admit of being activated selectively so as to use a greater or a lesser number of said trays in accordance with the nature and speed of the veneer strips being run.

15. A machine for edge-gluing wood veneer strips each of which has its grain running longitudinally of the edges which are to be joined, comprising a generally horizontal processing throat defined at the top by the lower run of an upper endless conveyor belt and at the bottom by the upper run of a lower endless conveyor belt, each of said belts comprising a multiplicity of parallel uniformly spaced bands and with the bands of the one conveyor occurring in the intervals midway between the bands of the other conveyor, a respective row of transversely extending longitudinally spaced apart pressure rolls bearing from below upon said upper run of the lower conveyor and from above upon said lower run of the upper conveyor and characterized in that the rolls of the lower said row occur in the intervals between the rolls of the upper said row, the two rows of rollers being so placed one relative to the other as to prescribe a sinusoidal path for veneer strips conveyed by said conveyor belts through said processing throat, the strips being introduced between said conveyor belts at the head end of the processing throat with the grain extending transverse to the path of conveyed travel and with the leading edge of each following strip abutting the trailing edge of the preceding strip, means being provided for so tensi'oning the bands that said strips have impressed thereon a simple harmonic wane running longitudinally of the grain from one to the other side edge of the strips.

16. The machine of claim 15 in which the bands are each comprised of a butt-welded ribbon of metal.

17. A machine according to claim 15 wherein means are provided for bodily raising and lowering the upper conveyor belt and the related pressure rolls for adjusting the machine to the handling of different thicknesses of veneer stock.

18. The method of edge-joining wood veneer strips having the grain running longitudinally of the edges which are to be joined, and which comprises feeding at least two of said strips one in following relation to the other along a travel path with the edges which 'are to be joined having glue applied thereto and with said glued edges extending transverse to the course of travel and juxtaposed the leading edge of the following strip against the trailing edge of the preceding strip, and in course of such travel impressing upon the juxtaposed edges a wave which represents a summation of sinusoids and which runs longitudinally of the grain from one to the other side edge of the strips.

19. The method of edge-joining veneer strips, and which comprises feeding at least two of said strips one in following relation to the other along a travel path with the edges which are to be joined having glue applied thereto and with said glued edges extending transverse to the course of travel and juxtaposed the leading edge of the following strips against the trailing edge of the preceding strip, and in course of such travel imposing upon the juxtaposed edges a wave representing a summation of sinusoids with the z axes of the individual waves being each at cross angles to the said juxtaposed edges.

20. The method of edge-joining wood veneer strips having the grain running longitudinally of the edges which are to be joined, and which comprises giving continuous travel to at least two of said strips one in following relation to the other along a course generally following the line of propagation of a comparatively flat wave with the 1'1 edges which are to be jeined havingzglne applied ihereto and? with said glued edges ex tendingn transverse to the donrse-travelledby the strips and juxtaposed the leading edge of the following strip against the 'trailing edge of the preceding strip, =and'dt1ring such travel impressing upon the juxtaposed edges a wave which represents "a'summation -of sinusoids and which runs longitudinally of the -grain"from une 'tothe other sideedge of the strips.-

References'Cit d in the fiie of i this patent UNITED: STATES PATENTS Jpnesl. Dec, 4, 1928 Weber' Feb; 12, 1929 Linquist" Apr. 20, 1943 Cai'lsQn Mar. 6, 1951 Lun'dberg' Oct. 30, 1951 U1ihschneidet- Feb. 24, 1953

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