US2974697A

US2974697A - Method and apparatus for making a veneer product

Info

Publication number: US2974697A
Application number: US708245A
Authority: US
Inventors: Elmendorf Armin; Henry F Herdey
Original assignee: Elmendorf Research Inc
Current assignee: Elmendorf Research Inc
Priority date: 1958-01-10
Filing date: 1958-01-10
Publication date: 1961-03-14
Anticipated expiration: 1978-03-14
Also published as: DE1207592B

Description

March 14, 1961 y A. ELMl-:NDORF ETAL 2,974,697

METHOD AND APPARATUS FOR MAKING A VENEER PRODUCT v Filed Jan. l0, 1958 `United Safes PrfO'Ce METHOD AND APPARATUS non A VENEER rRonUcT Armin Elmenderf and Henry F. Henley, Pale Aue, cent,

assignors to Elmendorf Researchlnc., 'Palo Alto, Calif., a corporation 'of California 'e The present invention is directed to a. method and 'apparatus for dstending veneer and making it pliable. The invention pertains to 'a method and apparatus for rupturingboth surfaces of veneer simultaneously. along closely spaced lines parallel to the grainof the' venee r .and thereby to distend or stretch it across the grain.

In many uses of veneer, it is desirable to provide space one method in commercial use to achieve this result, the veneer is wedged into a plurality of stripswithout structural connection between the strips. Paper faces are bonded to the surfaces of the wedged veneer ythereby 1o paratus'for'performing'the method of-the'presentinvew lines,v as the veneer is fed in a direction transverse to these lines, the'rupture lines following the grain of 'the wooi .i I A. Other purposes will appear from time'to time inl 'course of' the ensuing specification and claims.l 'Referring generally now to the drawings: Figure 1 is an' 'end view of a machine for flexing veneer in accordance with' the present invention,l with -certain .parts being known in section for purposes of clarity; Figure 2 is aj 'diagrammatic' illustration of another ap#- the 'Figure 3 is a `diagramma-ti'c V showing lof another kv,api 'paratus for performing thefmethod of the 'present4 inyenf' tiongavndv, M, Y j Figure '4 is' plan view of 'a sheet of veneer treated in'accordance with the present invention and showing the producing a board that has many uses. Adisadvantage found in this product resides in the fact that the spaces between the strips telegraph throughithe `paper facings, The spacesshow up as a" plurality of evenly spaced parallel lines. Such lines are objectionable in many ofthe uses' of the board, such as for the constructionof luggage and.for.`furniture panels.

In 'the case of very thin veneers, it is common corn-l mercial practice'rst to bond a flexible backing to the veneer and thus to rupture the exposed surface of the veneer at closely spaced intervals by stretching this sur'- face. The rupturing of the surface of the veneer in'this method causes the sheet to curl and it is necessary to pass the sheet through the machine a second time with the Veneer on the reverse side so that the backing. is stretched and the resultant sheet is flattened out. is possible with cloth backing because thel cloth can also be stretched. With paper backing, the spread ofthe veneer often makes it dificult toi unfurl' the sheet for' the second pass.

v The present invention pertains to a method and apparatus for distending veneer which may be used with either thin or thick veneers without a backing and is especially useful for distending veneers of a thickness from V16 inch to 9/16 inch.

)Veneer processed in accordance with the vmethod and apparatus of the present invention has been ruptured on both surfaces; its width is thereby increased from 2% to 15%. When veneers distended in this manner are faced with strong paper they can expand internally in lines of rupture on-the opposite surfaces of the veneer'. I Like'elements are designated by like characters throughout the specification and drawings.'

In accordance' with the' method of the present inven'f within the sheet into which the wood can expand. In

tion, sheets of veneer 'are fed in a direction transverse to' the grain of' the' veneer. The sheet" ofn veneer` progresses in 'this vdirection to a rupturing Vzone of treatment, At the, rupturing zone the veneer is bent o rflexed to the point of rupture -along three parallel lines, one line being along one surface and the other two along'v the oppositie nesses of veneer, the radius Vof'curvature necessary; vto

produce 'rupture may vary. For any given v `wood, o1j thickness thereof, vthe radius of curvature necessary o produce'adequate rupture may be determined. y .ji It is preferable to vfeed the sheets of veneer continuf ously through the rupturing zone. The rupturelinesr or fissures thus formed in the sheetofveneer are no t evenly spaced and some are more pronounced thanuothers.but they are always close together if the bending curvature is sharp.' .They are not visible when the veneer is attened out. They are seldom very long, consequently-,

although the veneer may have been rendered quite limp;

it still holds together and can be readily,handled. With particular reference now to Figure 1, a suppor-t ing surface is shown at 1. A second supportingsurface is shown at 4. The surface 4 is adapted to support a aboutthe same amount and they remain relatively flat through the paper faces of the final parallel lines on opposite surfaces of the veneer whereby the veneer'is ruptured at close intervals following the Vgrain ofthe Wood crossing those lines Anotherpurpose of the present invention is'the provision of a method and apparatus for progressively'rupturingiopposite surfaces' of a veneer-'sheet along parallel sheet of veneer after it has been ruptured in the ruptura ing zone 3. The machine includes small flexing rollers 5, 6 'and 7 which are adapted for rotation in the direction of the arrows shown in Figure 1. The rollers 5, 6 and 7 are adapted for rotation about parallel axes thatare triangularly arranged (as viewed in {Figure 1 `The roller 7, which may be designated a pressuresurface,7 is positioned so that. its axis is` beneathlthe'supportng: ASuru faces 1 and 4, butwi'th its peripheral surface extending to alev'ell abovethe supporting Vsurfaces 1 and upper flexing-'rollers 5 'and' 6,` which may `be designated constraining surfacesparelspa'ced above V the1' v ver. prese sure' roller7, and withl their-axes spaced on opposite sides of a vertical plane passing through the axis of the 'ifollerj/;g

The 'lower surfacesof therollersS and @form-cont strainingv fulcrums for the veneer as'itisthrust u the roller 7. f. f' v- It, 'should be, understood'l that "the rollerssho'l in Figure 1 'are each provided' with journalswhich are power source in a manner such as to rotate the rollers 5, 6 and 7 at equal peripheral speeds. Idler rollers 8 and 9 are positioned between the drive roller 10 and Pressure roller 7.-

' In using the apparatus illustrated in Figure l, sheets of veneer'are fed along the supporting surface `1 in the direction of the arrow shown at the left-hand Side of Figure 1- The veneer .is fed in this direction with yits grain extending generally parallel tothe axes of the neX- ing rollers. When the vedge of the veneer contacts the peripheral surface of the roller 7, the veneer is forced upwardly. As the .veneer progresses through the space between the rollers '.5 and @the leading edge thereof contacts the roller 5 which then forces the veneer downwardly. As the leading edge continues downwardly, it Contacts the supporting snrfaoe 4 .and slides along this surface.- As the" sheet .of veneer progresses along this path, each succeeding portion of the veneer is ruptured along lines parallel to the `flexing .rollers designated at 12. 13 and 14 each .rupture ,following the grain of the veneer.

Figure 2 is a diagrammatic showing of another apparatus that may housed to perform themethod of the present invention. In this figure, the veneer is fed along entry and exit surfaces 21 and 22, respectively. The veneer is fed in the direction of the arrow with the grain of the veneer transverse to the direction of movement- A rupturing zone is designated at 23- In Fignre 2 an upper snfrfaee 2.5 is adapted to constrain the Sheet of Veneer 26 in a substantially rectilinear path While it passes through the rupturing zone. A plunger 24 is positioned between the surface 21 and 2 2 and is adapted to be reciprocated in a vertical direction transverse to the movement of the veneer. The plunger 2,4 is adapted to be reciprocated from a point spaced above the surfaces 21 and 22 to a point spaced below the surfaces. 'Ihe plunger 24 may have a curvilinear upper surface or pressure surface which is adapted to bear against the lower surface of the veneer.

"That portion of the surface 25 which is opposite to the plunger 24, is curvilinear as at 27. The radius of curvature of the portion 27, which may also be considered a constraining surface, should be slightly less than the radius of curvature which will produce'rupture. The portion 27 extends to

points

28 and 2 9 on opposite sides of the plunger 24. The arrangement is such that when the plunger' 24 is in its uppermost position, the veneer 26 is constrained in the gap between the surfaces 2 1 and 25 and rupture of the convex surfaces of the veneer takes place along the lines parallel to the edge of the plunger 24 at 30, 31 and 32.

The plunger 24 is adapted to be reciprocated at a speed correlated with the desired speed of the feed of the veneer 26 which moves forward a short distance each time that the plunger is out of the way. As in the case of the apparatus shown in Figure l, rupture will occur at 32 if rupture has not previously occurred along this line when the veneer entered the rupturing zone.

Figure 3 illustrates a preferred form of apparatus With which to practise the'method of the present invention. In Figure 3 an anvil roller 4-1 is adapted to drive a. small flexing roller 42. Supporting surfaces are provided on opposite sides of the flexing roller 42 as shown at 43 and 44. A cushion roller is employed as shown ,at 45, The roller 45 carries a layer of resilient material .46 on the peripheral surface thereof. The layer 46may be made ofsoft rubber or rubber-like material.

` `When a sheet o f veneer 47 is fed in the direction of the arrow shown in Figure AEl (transverse to the grain of the veneer) the leading edge of the veneer ys heet is clamped or constrainedibetween the supporting surface 43 and rubber surface 46 in what is known as a clampin g zone. `When the leading edge contacts the pressure roller or. liexing .roller 4.2 it is foreed upwardly, thus .compressing thelayerot resilient .material 4,6 and bending 4 the veneer to the rupture point along a line 51 parallel to the flexing roller 42. 'As the leading edge'of the veneer passes over the roller 42, it is forced downwardly by the rubber towards the exit surface 44 and then progressed outwardly from the rupturing zone. In this passage it is successively ruptured along the upper surface at 50 and then along the lower surface at 52. The veneer is ruptured simultaneously along one line on one surface of the veneer and along two lines parallel to it on the opposite snrfaee,

A.The radinsA of enrvatnre et the ileXing roller is less than that minimum radius which will produce rupture of the surface of the yeneer, in the case of the embodiments illustrated in Figures 1 and 2, the surface of the veneer opposite to the upper edge of the flexing roller 42 is ruptured at 50 while ruptures occur in the opposite surface of the veneer along the lines at 51 and 52.

In Figure 3 feeding .of the veneer is automatically provided by the clamping action Yexerted on the veneer by the surface of the rubber 46 and the supporting surface 4 3. The thrust so provided performs an important function as it causes the veneerv to overcome the resistance imparted to the leading edge by the ilexing roller. Without this thrust, thick veneers are stopped by the flexing roll. This thrust is especially important when veneer i;e inch to 3/16 inch are to be made iiexible. Once the veneer edge has been pinched between the tlexing roll and the cushion roll, it proceeds on through the machine continuously and without hindrance. I have vfound that the friction between the cushion and the veneer is greater than the combined resistance of the friction on the supporting ymetal surface and the resistance of the flexing roller.

Figure 4 is a plan view of a sheet of veneer which has been treated in accordance with the present invention. For veneers that range in thickness from 1,/16 inch to @/16 inch, we obtain satisfactory results with a flexing roller 3/ 8 in ch in diameter positioned so that its upper edge is from $42 inch to 1A@ inch above the supporting surface 43, with the cushioning surface positioned so that the space between it and the supporting surface is less than the thickness of the veneer, the exact distance depending upon the softness of the rubber used for the cushioning roller. Satisfactory results are obtained with a rubber cushion 1/2 inch thick, `and the rubber having a durometer of 40, and the diameter of the cushion roller being "12 inches.

In Figure 4, which is a plan view of the flexed veneer, zones AA and BB show the fissures following the grain of the wood produced by the bending of the lower surface of the veneer and CC shows the fissures caused by the bending of the upper surface of the veneer. This result is obtained with each of the devices shown in Figures l, 2 and 3. When the veneer is flattened out, these fissures are substantially invisible, even though the width 0f the veneer has been increased by the llexing action from 2% to 15%. When veneers so processed are faced with paper, no ssuring can be seen nor do any rupture lines telegraph through the paper.

Zone CC in Figure 4 corresponds to the rupture line or zone 12 in the upper surface of the veneer in Figure l, while Zones and BB correspond to the rupture lines or zones 13 and 14 in the lower surface of the veneer in Figure 1.

Whereas we have shown and described an operative form of the method of thc invention, and certain operative forms o f apparatus that may be used with the invention, it s houldbe understood that this showing and description thereof should be taken in an illustrative and diagrammatic sense only. There are many modifications of the invention which will fall within the scope and spirit thereof and which will be apparent to those skilled in the art. The scope of the invention should be limited only to the vscope of the hereinafter appended claims.

We claim:

1. A method of distending veneer Aand making it pliable including the steps of feeding the -Veneer in a direction per pendicular to the grain into a clamping zone, clamping the veneer between an unyielding surface and a moving yielding surface, then bending the veneer =by progressively increasing the compression of theyielding surface as the veneer advances until a point of maximum compression is reached, then progressively releasing lthe compression While bending the veneer in the reversed direction, then bending the veneer in the same direction as the rst bending while progressively clamping the veneer between said moving yielding surface and a second unyielding surface, thereby increasing the width of the veneer at least 2 percent.

l2. The method of claim 1 wherein the distance between the uncompressed yielding surface and either one of said unyielding surfaces is less than the thickness of the veneer.

3. A method of distending veneer and making it pliable including the steps of continuously feeding the veneer in a direction perpendicular to the grain into a rupturing zone, continuously maintaining a variable pressure over the entire area of one surface of the veneer as it passes through the ruptun'ng zone, said continuously maintained pressure being a minimum as the veneer enters' and leaves the rupturing zone and progressively increasing to and decreasing from.a maximum as it passes through the rupturing zone, continuously maintaining pressure upon the opposite surface of said veneer -as it enters and leaves the rupturing zone and continuously applying pressure to said second-named surface of the veneer at a point intermediate said entering and leaving points of maintained pressure to bend the veneer in reverse curvature as it passes through said rupturing zone so as to simultaneously rupture both surfaces of said veneer.

4. The method of claim 3 further characterized in that the point of maximum pressure on said first surface of the veneer is aligned with the point of pressure application on the opposite surface of the veneer.

5. The method of claim 4 further characterized in that said veneer is first bent -away from the point of pressure application to said second-named side, then back toward said point of pressure application, yand thenis bent in the direction of said first-named bending.

References Cited in the file of this patent UNITED STATES PATENTS 852,826 Doherty et al. May 7, 1907 1,778,250 Elmendorf Oct. 14, 1930 1,809,681 Elmendorf June 9, 1931 1,902,032 Horine Mar. 21, 1933 2,336,535 Elliott et al Dec. 14, 1943 2,343,016 Loughborough Feb. 29, 1944 2,815,780 Higgins Dec. l0, 1957 FOREIGN PATENTS 553,854 Germany July l, 1932 348,416 Great Britain May 14, 1931 OTHER REFERENCES A Real Lumber Stretcher, Popular Mechanics, July 1958. (Page 131 relied on. Copy in Scientic Librarv and in Division 20.)