US3224919A

US3224919A - High speed veneering process

Info

Publication number: US3224919A
Application number: US246593A
Authority: US
Inventors: Elmendorf Armin
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-12-21
Filing date: 1962-12-21
Publication date: 1965-12-21
Anticipated expiration: 1982-12-21

Description

' Dec. 21, 1965 ELMENDORF 3,224,919

HIGH SPEED VENEERING PROCESS Filed Dec. 21, 1962 2 Sheets-Sheet 1 M V 3 #7 K 30 J L 1 y 3 INVENTOR.

Dec. 21, 1965 A. ELMENDORF 3,224,919

HIGH SPEED VENEERING PROCESS Filed Dec. 21, 1962 2 Sheets-Sheet 2 7 a 3 IN VEN TOR. j Jim/M [Zia/M90;

United States Patent 3,224,919 HIGH SPEED VENEERING PROCESS Armin Elmendorf, 860 Charleston Road, Palo Alto, Calif. Filed Dec. 21, 1962, Ser. No. 246,593 3 Claims. (Cl. 156299) This invention relates to a high speed veneering process and is a continuation in part of my co-pending application Serial No. 84,086, filed January 23, 1961, now abandoned.

A primary purpose of the invention is a high speed veneering process in which strips of veneer are moved into edge contact with each other and line bonded to a moving panel, prior to the final permanent bonding step.

Another purpose is a process for splicing thin dry veneer on a moving panel.

Another purpose is an automated method, suitable for high speed operation, for veneering panels.

Another purpose is a method of the type described requiring a minimum of manual labor.

Other purposes will appear in the ensuing specification, drawings and claims.

The invention is illustrated diagrammatically in the following drawings wherein:

FIGURE 1 is a diagrammatic illustration of the various steps in my high speed veneering process,

FIGURE 2 is a side view, with parts in section, of an apparatus for splicing veneer,

FIG. 3 is a partial vertical elevation through the apparatus illustrated in FIGURE 2, and

FIGURE 4 is a partial vertical section through the press used in permanently bonding the veneer to the panel.

In FIGURE 1, a stack of panels is indicated at 10. Any type of ligno-cellulosic panel such as particle board, plywood, insulation board, hardboard, or the like, may be veneered in this process. One surface of each of these panels has been coated with an adhesive and the adhesive has been dried. This step is completed prior to stacking the panels and may be performed in any conventional manner. The type of adhesive may vary, although some types of melamine adhesives as well as some protein adhesives are satisfactory. It is preferred to apply the ad hesive as a solution after which it is force dried.

A workman may take one of the panels from the stack and lay this panel across a pair of spaced belts 12 or some other suitable conveyor arrangement. Any conventional drive may be used. The belts 12 are stationary when a panel, indicated at 14, is placed on them. A thin sheet of veneer, in a dry state, is placed along one edge of the panel 14, as indicated at 16. The workman may flatten the sheet 16, as thin veneers are frequently badly buckled, and may then temporarily bond this first sheet to the adhesive coated surface of the panel to provide a set edge against which a succeeding veneer sheet may be shoved. This bonding may be accomplished in any manner, but preferably by applying heat at spaced points or along spaced lines to activate the adhesive. This may be done while the panel is stationary or moving. Next, additional veneer sheets, indicated at 18, with the number of additional veneer sheets depending upon the size of the panel and the size of the veneer, are placed on the adhesive coated surface in a generally parallel arrangement with the veneer sheet 16. Adjacent edges of the veneer sheets 18 are not in contact. The edge of each sheet is spaced a small distance from its adjacent edge. The forming line is still at rest as the above operation is taking place.

After the sheets 18 have been placed in position on the panel 14, the belts 12 are started in motion and the panel is removed through a splicing zone indicated generally at 20. At the splicing zone an adjoining veneer sheet 3,224,919 Patented Dec. 21, 1965 18 is pushed against the edge of temporarily bonded sheet 16 and then said sheet 18 is temporarily bonded to the panel along parallel lines. This operation takes place as the panel is moving. The belts will stop when the panel reaches the station indicated at 22. A second panel is now removed from the stack 10 and veneer sheets are placed on it in the manner described. The belts 12 are again started and the panels move, in the direction of arrow 23, with the stationary panel at station 22 being moved into a hot plate press indicated at 241. The panel will remain in the press a sufficient time to permanently bond the veneer sheets to the surfaces of the panels, which were previously line bonded at the splicing zone 20, to the panel.

The pressing cycle may take about 20 seconds, with the belts moving for about half of this time and the remaining time being spent in the press. During the period the panels are moving the splicing operation takes place.

FIGURE 4 illustrates the hot plate press. The upper platen 26 is movable and the lower platen 23 is stationary. The upper platen and also the lower platen, if desired, may be heated in any conventional manner. The belts 12 run over blocks or the like 30 which are upwardly biased by springs 32 to the position of FIGURE 4. When the upper platen 26 comes down, and the panel to be pressed is in position, the belts will be depressed so that they will be level with the upper surface of the lower platen 28 during bonding. The time in the press will depend upon the thickness of the veneer and the type of adhesive. A 5 to lO-second period in the press has been found to be satisfactory.

After a sufiicient time in the press, the belts 12 will move the panel out of the press to the next station indicated at 3 The direction of movement of the panel will now be changed, to that indicated by the arrow 36, and after the next rest period during which a panel is bonded in the press 24 and veneer strips are laid on another panel, the belts will move the panel through a bending station indicated at 38. Heat plates positioned at different angles relative to the panel surface or heated twisted plates, as at 39, along the edges of the panel, will be used to bend the veneer lips which extend over the panel surface down along the edges of the panel. This is done as the panel is moved. After the bending step the panel will stop at the next station indicated at 40, and while the panel is at rest at this point, the edges will be bonded to the panel by means of hot bars or the like 41.

After edge bonding has been completed, the panel will move past a pair of spaced trimming saws 42 which will remove any projecting veneer along the edges of the panel. Sanding discs or sanding belts are equally satisfactory for trimming.

After the edges have been trimmed, the panel again will change direction, as indicated by arrow 44, and will be moved past saws or the like 46 which will trim the ends of the panel to the length desired. The veneer alone may be trimmed, or both the veneer and panel may be cut.

FIGURES 2 and 3 illustrate in detail the operation at the splicing zone. A pair of spaced bars or rods 58 which may be heated in any conventional manner, for example steam, electricity, or oil, are positioned above a panel 60 carrying a veneer sheet 62 on its upper adhesive coated surface. The bars 58 may be pivoted, as at 64, and may receive downwardly directed yielding pressure from the spring arrangement 66. It should be noted that the lower surface of the bars 58 is upwardly curved, as at 68, so that at the joint between adjacent spaced veneer edges, the lower edge of the bar is spaced a distance from the panel 60 greater than the thickness of the veneer. This is necessary in order to allow the veneers to be moved into edge contact.

A drum 70, which may be rotated in any conventional manner, and is moved at a peripheral speed greater than the speed of the belts 12 and the panel 60, has a pair of spaced collars each comprising an inner metal ring 72 and an Outer ring 74 formed of a cushion material, for example sponge rubber or the like. An outer layer 76, formed of a thin rubber, is placed on the cushion layer 74 to provide traction.

In operation, the spaced collars on the drum 70 will contact a veneer sheet on its upper surface and will slide the veneer sheet toward the next adjacent sheet. The pressure applied by the spaced collars in a direction parallel with the panel 60 will be greater than the resistance of the dry adhesive to this sliding movement. As the drum rotates at a peripheral speed greater than the speed of the panel, the veneer sheet indicated at 78 in FIGURE 2 will slide into edge contact with the veneer sheet 62. Once these two sheets are in edge contact, they will be maintained in edge contact by the continuing pressure applied by the rotating drum 70. As the resistance to further movement of the veneer '78 is greater than the horizontal component of the pressure applied by the rotating collars, the collars will slip over the upper surface of the veneer thus maintaining edge contact. In a modified arrangement, a friction clutch may be provided so that slippage takes place in the clutch after the veneers are in edge contact.

As stated above, the lower surface 68 of the bars 58 is curved so that the veneers may be slid together. In addition this curved surface will tend to gradually flatten buckled veneers so that they may be then bonded along spaced lines to the panel or substrate 60. It is important to note that spot bonding is done while the panel is in motion and therefore the hot bars are never in contact with the veneer more than a few seconds. There is therefore no scorching of the veneer surface. The bonding will take place along spaced lines which run across the grain of the veneer sheets.

The use, operation and function of the invention are as follows:

The present invention is directed to a high speed process suitable for bonding veneer strips to a panel. The veneer should be dry. A thickness of about inch to & inch is satisfactory, although this is not a limitation. Each of the panels to he veneered is first covered with an adhesive and the adhesive is either force dried or allowed to air dry. The panels are then stacked and removed one at a time by a workman during the period when the belts are at rest. One of the panels is placed across the belts and a group of veneer sheets are placed on top of the adhesive coated surface. The sheet along one edge of the panel is flattened and bonded along parallel lines or otherwise temporarily bonded to the panel. The panel then passes through a splicing zone in which each sheet of veneer is automatically and successively flattened and moved into edge contact with the adjacent sheet of veneer and then temporarily bonded to the underlying panel. The first sheet is held to the panel by such temporary bonding to provide an edge against which a succeeding veneer sheet is shoved and held While it likewise is temporary bonded along parallel lines. This splicing step takes place while the panel is moving. After bonding the veneer to the surface and edges permanently, the edges are trimmed, in both directions, to complete the formation of the veneered panel.

Of particular importance in the invention is the fact that the splicing step takes place while the panel is moving. Heretofore it was necessary to perform the splicing step either by hand, or by machine, but in any event, While the panel was stationary. The present invention greatly increases the speed of the entire panel veneering process. By using thin veneers, dry adhesive, and a very short time in the hot press, commercially flat panels may be produced even though the veneer is applied to only one side.

Whereas the preferred form of the invention has been shown and described herein, it should be realized that there are many modifications, substitutions and alterations thereto, within the scope of the following claims.

I claim:

ll. A method for applying veneer to one surface of a ligno-cellulosic panel by a high speed process, which includes the steps of,

applying a liquid adhesive to one surface of a panel having a ligno-cellulosic surface,

drying the adhesive,

placing the panel on means adapted to convey the panel to a splicing station,

while the panel is in motion, temporarily bonding a first veneer sheet to the panel at a bonding station by applying pressure and heat along spaced parallel lines whose position is fixed,

placing a second veneer sheet on the panel in spaced relationship to the first veneer so that there is a gap between the adjoining edges,

and while the panel is in motion, closing the gap between the temporarily bonded first veneer sheet and a second veneer sheet at the splicing station, said gap being closed by sliding said second veneer sheet on the adhesive until it comes into contact with the edge of the first veneer sheet which has been temporarily bonded to the panel,

maintaining edge contact While the panel moves and While the second veneer sheet is temporarily bonded to the panel along spaced parallel lines whose position is fixed,

moving the panel to a permanent bonding station, and

permanently bonding the temporarily bonded veneer sheets over the entire panel by heated pressing means.

2. A method for applying veneer to one side of a lignocellulosic panel which includes the steps of,

applying liquid adhesive to one surface of a panel having a ligno-cellulosic surface,

drying the adhesive,

placing the panel on means adapted to convey the panel to a splicing station,

temporarily bonding a first sheet of veneer to the panel,

placing a second veneer sheet on the dry adhesive,

positioning said sheets in spaced relationship so that there is a gap between the adjoining edges of said successive sheets, and while the panel is in motion, closing the gap between the temporarily bonded first veneer sheet and a second veneer sheet at a splicing station by sliding said second veneer sheet on the adhesive until it comes into contact with the edge of the veneer sheet which is temporarily bonded to the panel,

maintaining edge contact while the panel moves and while pressure and heat are applied along parallel lines whose position is fixed, thereby temporarily bonding the second sheet to the panel,

moving the panel to a permanent bonding station, and

3. The process of claim 2 further characterized in that following the step of obtaining edge contact, said edge contact is maintained by means which slips over the surface of the veneer.

References Cited by the Examiner UNITED STATES PATENTS 1,875,056 8/1932 Loetscher 156-291 2,572,772 10/1951 Skoog 156-296 2,587,985 3/1952 Elmendorf 156-71 3,031,356 4/1962 Bousquet et al 156-202 3,133,850 5/1964 Alenius 156-558 EARL M. BERGERT, Primary Examiner.

Claims

1. A METHOD FOR APPLYING VENEER TO ONE SURFACE OF A LIGNO-CELLULOSIC PANEL BY A HIGH SPEED PROCESS, WHICH INCLUDES THE STEPS OF, APPLYING A LIQUID ADHESIVE TO ONE SURFACE OF A PANEL HAVING LIGNO-CELLULOSIC SURFACE, DRYING THE ADHESIVE, PLACING THE PANEL ON MEANS ADAPTED TO CONVEY THE PANEL TO A SPLICING STATION, WHILE THE PANEL IS IN MOTION, TEMPORARILY BONDING A FIRST VENEER SHEET TO THE PANEL AT A BONDING STATION BY APPLYING PRESSURE AND HEAT ALONG SPACED PARALLEL LINES WHOSE POSITION IS FIXED, PLACING A SECOND VENEER SHEET ON THE PANEL IN SPACED RELATIONSHIP TO THE FIRST VENEER SO THAT THERE IS A GAP BETWEEN THE ADJOINING EDGES,S, AND WHILE THE PANEL IS IN MOTION, CLOSING THE GAP BETWEEN THE TEMPORARILY BONDED FIRST VENEER SHEET AND A SECOND VENEER SHEET AT THE SPLICING STATION, SAID GAP BEING CLOSED BY SLIDING SAID SECOND VENEER SHEET ON THE ADHESIVE UNTIL IT COMES INTO CONTACT WITH THE EDGE OF THE FIRST VENEER SHEET WHICH HAS BEEN TEMPORARILY BONDED TO THE PANEL, MAINTAINING EDGE CONTACT WHILE THE PANEL MOVES AND WHILE THE SECOND VENEER SHEET IS TEMPORARILY BONDED TO THE PANEL ALONG SPACED PARALLEL LINES WHOS POSITION IS FIXED, MOVING THE PANEL TO A PERMANENT BONDING STATION, AND PERMANENTLY BONDING THE TEMPORARILY BONDED VENEER SHEETS OVER THE ENTIRE PANEL BY HEATED PRESSING MEANS.