US 3795560 A
Description (OCR text may contain errors)
March 1974 MASAICHIRO MATSUMOTO ETAL 3,795,560
METHOD FOR MAKING PLYWOQD 4 Sheets-Sheet 1 Filed July 22, 1971 MASAICHIRO MATSUMOTO ETAL 3,795,560
March 5, 1974 METHOD FOR MAKING PLYWOOD 4 Sheets-Sheet 2 Filed July 22, 1971 March 1974 MASAICHIRO MATSUMOTO EI'AL 3,795,560
METHOD FOR MAKING PLYWOOD Filed July 22, 1971 4 Sheets-Sheet 5 March 1974 MASAICHIRO MATSUMOTO ETAL 3,7
METHOD FOR MAKING PLYWOOD 4 Sheets-Sheet 4 Filed July 22, 1971 US. Cl. 156300 2 Claims ABSTRACT OF THE DISCLOSURE Method for producing plywood comprises steps of delivering first veneer with adhesive on upper surface thereof from first station to main conveyor running transverse to direction of delivery of first veneer. Method also includes step of delivering second veneer with adhesive on upper surface thereof and grain thereof transverse to grain of first veneer from second station independent of first station to main conveyor. Second veneer is compiled on top of first veneer, and thereafter several additional veneers with adhesive on upper surfaces thereof are independently delivered from additional stations to main conveyor. Additional veneers have alternating grain directions and are compiled on top of one another and first and second veneers. Finally, uppermost veneer without adhesive thereon is delivered from final station to main conveyor, and thereafter uppermost veneer is compiled on top of other veneers so that grain thereof is transverse to grain of adjacent veneer.
BACKGROUND OF THE INVENTION The present invention relates to a method for producing plywood comprising a plurality of individual wood veneers.
Prior to the present invention numerous procedures have been proposed for producing plywood sheets. One of the prior art plywood producing procedures involves coating individual wood veneers and compiling plywood sheets by delivering and stacking one veneer after the other at a single processing station. The efficiency of such an operation is quite low.
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to avoid the shortcomings of the prior art by providing a unique method for producing plywood in a beneficial and highly economical manner.
Another object of the present invention is to provide a method of producing plywood wherein adhesive material is applied to the wood veneers in a manner that avoids irregularities of the coating on the veneer.
In accordance with the present invention, a method for producing plywood comprising a plurality of veneers includes the step of delivering a first veneer with adhesive on the upper surface thereof from a first station to a main conveyor line that runs transverse to the direction of delivery Of the first veneer. Next, a second veneer with adhesive thereon and the grain direction thereof transverse to the grain of the first veneer is delivered from a second station independent of the first station to the main conveyor line. The second veneer is compiled on top of the first veneer. Several additional veneers with adhesive thereon and alternating grain directions are independently delivered from additional stations to the main conveyor line, and these additional veneers are compiled on top of one another and the first and second veneers. Finally, an
United States Patent ice uppermost veneer without adhesive thereon is delivered from a final station to the main conveyor line, and thereafter the uppermost veneer is compiled on top of the other veneers so that the grain thereof is transverse to the grain of its adjacent veneer.
The plywood producing method of the present invention may also include the steps of applying adhesive to the upper surface of each veneer except the uppermost one by applying the adhesive along the veneers in the same direction as the grain thereof.
BRIEF DESCRIPTION OF THE DRAWING Novel features and advantages of the present invention in addition to those mentioned above will become apparent to those skilled in the art from a reading of the following detailed description in conjunction with the accompanying drawing wherein:
FIG. 1 is a top plan view of an apparatus utilizing the method of the present invention;
FIGURE 2 is a simplified side elevational view part of which is in cross section of the apparatus shown in FIG. 1;
FIG. 3 is a perspective rear view of the veneer carrier of the apparatus shown in FIG. 1;
FIG. 4 is an enlarged cross sectional view taken along line 44 of FIG. 1;
FIG. 5 is an enlarged cross sectional view taken along line 55 of FIG. 1;
FIG. 6 is an enlarged cross sectional view taken along line 66 of FIG. 1;
FIG. 7A is a fragmental top plan view of the vacuum conveyor as used in the apparatus of FIG. 1;
FIG. 7B is a fragmental cross sectional view in elevation of the vacuum conveyor as used in the apparatus of FIG. 1;
FIG. 8 is a side elevational view illustrating the downstream end of the main conveyor of the apparatus of FIG. 1; and
FIG. 9 is a simplified perspective view illustrating the structure for stacking plywood.
DETAILED DESCRIPTION OF THE INVENTION Referring in more particularity to the drawing, FIGS. 1 and 2 illustrate a plywood producing machine that utilizes the method of the present invention. The machine has a plurality of conveyors 1 that form a main conveyor line. The primary purpose of the main conveyor line is to carry and transport individual wood veneers from left to right, as viewed in FIGS. 1 and 2. The path of motion of the main conveyor line is next to a series of individual apparatus stations 2-1, 2-2, 2-3, 2-4 and 2-5. Each of these apparatus stations functions to deliver plywood veneer to the main conveyor line.
As viewed in FIG. 1, the apparatus stations 2-1, 2-3 and 2-5 are located at the left end, center and right end of the main conveyor line. These apparatus stations provide veneers which have grain directions parallel to the direction in which the veneers are delivered to the main conveyor. As shown in FIG. 1, the direction of delivery of the veneers to the main conveyor is transverse to the direction of travel of the main conveyor.
The apparatus stations 2-2 and 2-4 are located directly to the left and right of the center apparatus station 2-3. These stations provide veneers having grain directions transverse to the direction of delivery of the veneers to the main conveyor line. In other words, in the apparatus stations 2-2 and 2-4 the grain of the veneers is transverse to the direction the veneers are delivered to the main conveyor.
Primarily, the individual apparatus stations along the path of travel of the main conveyor 1 function to deliver plywood veneers to the main conveyor. The individual veneers are compiled one above the other as they travel along the path of the main conveyor. Since every other apparatus station delivers veneers having similar grain orientations but different from the balance of the vaneers, the plywood produced has adjacent veneers of different grain orientation.
As shown best in FIG. 3 a carrier 3 is associated with each of the apparatus stations at a location on the main conveyor. Each carrier has elongated slots 3 which allow pushers 4' to pass therethrough. When a veneer is placed on a carrier 3, the pushers 4 force the veneer off the carrier onto the conveyor 1 where it is conveyed to the next station at a location below the carrier associated with the next station.
The apparatus for feeding a veneer to the main conveyor is constructed as follows. As shown best in FIG. 4, a lifter 5 in each of the apparatus stations 2-1, 2-3 and 2-5 provides a veneer A-1 having a grain direction transverse to the movement of the main conveyor 1. The uppermost surface of the individual veneers A-l located on the lifter 5 partly faces the leading end of a suction device 6' associated with a vacuum feeder 6. The suction mouth 6' also faces part of the leading end of a conveyor 7. When an air cylinder 8 is operating the vacuum feeder 6 draws a part of the uppermost veneer A-1 in the stack and the veneer is then forwarded in the direction of the arrow. Ultimately, the veneer reaches another conveyor 19, and at this location adhesive 9 and hardener 10 are coated on the surface of the veneer by flowing or spraying techniques. In the case of apparatus station 2-5 no adhesive applying structure is provided since the uppermost veneer in the plywood sheet does not require any adhesive. As indicated above, the individual plywood veneers from the apparatus stations 2-1, 2-3 and 2-5 are delivered to the main conveyor 1 so that the grain direction of the veneers is transverse to the direction of the main conveyor. Accordingly, in accordance with the present invention the ad hesive is applied to the veneers at these apparatus stations along a direction which is the same as the direction of travel of the veneers to the main conveyor. This technique operates to apply adhesive to the veneer in the same direction as the grain thereof.
Generally, a veneer which is dried has a wave-like curve or ridge along its grain, and when adhesive is applied by flow coating techniques an even distribution of adhesive is achieved when the adhesive is applied in the same direction as the grain. In the event adhesive is applied in a direction transverse to the direction of the grain, the back sides of the raised curves and ridges are not coated with adhesive. Ultimately, this defect is reflected in a very poor bond between adjacent wood veneers in the finished plywood sheet. The present method avoids irregularities in the adhesive coating by applying the adhesive in the same direction as the veneer grain.
After the individual veneer at apparatus stations 2-1 and 2-3 is coated with adhesive it is delivered to the leading surface of the vacuum conveyor 12 operated by a vacuum feeder 11, as shown best in FIG. 4. The vacuum conveyor 12 has numerous small heads 13 fabricated or coated with material, such as Teflon, for example, which does not stick to the adhesive coated veneer. The conveyor 12 has vacuum holes 14 and when these heads engage the veneer they anchor the veneer to the conveyor 12 as long as the vacuum feeder 11 is operating. Ultimately, the adhesive coated veneer is transported to a position directly above the main conveyor 1 and a limit switch 15 operates an air cylinder 8 and a valve 6" associated with the vacuum feeder 6 to effect a termination of the suc-- tion delivered to the head 6'. Also, when the veneer is transported to the left, as viewed in FIG. 4, it engages a limit switch 16 associated with an air cylinder 17, the vacuum feeder 11 and a valve 11' to thereby terminate the vacuum delivered to the suction heads 13. When this vacuum is cut off, the adhesive coated veneer is dropped downwardly onto the carrier 3. Subsequently, the lifter 5 is slightly raised to a predetermined height determined by a limit switch 18 which detects the height of the supply. When the lifter 5 is elevated and the height of the pile of veneer reaches the predetermined amount, the valve 6" of the vacuum feeder 6 is opened to commence another feeding and coating operation of a veneer to the main conveyor 1.
As indicated above, apparatus stations 2-2 and 2-4 deliver wood veneers to the main conveyor line 1 in a direction so that the grain of these veneers is parallel to the direction of travel of the main conveyor. In FIG. 5 a stack of veneers A-2 are located on a lifter 5. The grain direction of these veneers is transverse to the direction in which they are delivered to the main conveyor 1. The uppermost veneer in the stack on lifter 5' is delivered to a conveyor 23 by a suction device including a vacuum feeder 21 and a head 21.. When the uppermost veneer in the stack is drawn toward the vacuum feeder 21 a conveyor 22 is operated to urge the uppermost veneer to the left, as viewed in FIG. 5. Next, adhesive 24 and hardener 25 are flowed or otherwise coated onto the veneer by applying them in the same direction as the grain. As the coated veneer moves further to the left, as viewed in FIG. 5, on a conveyor 30, the veneer ultimately hits a limit switch 31 which causes the veneer to take a right angle turn. The turning is accomplishedby activation of the limit switch 31 which causes a lifter 33 having bars 32 to lift the coated veneer upwardly toward a vacuum feeder 26. A vacuum conveyor 27 associated with the vacuum feeder 26 cooperates with a vacuum feeder 26' to convey the coated veneer to the main conveyor line 1. The limit switches 15' and 18, and the lifter 5' operate in the same'manner as described above in conjunction with switches 15, 18 and lifter 5. Also, the vacuum conveyor 27 is constructed in the same manner as described above in conjunction with the conveyor 12.
When the plywood veneer A-2 is finally conveyed to a position directly over the main conveyor 1, the veneer hits a limit switch 28 to cut off the vacuum operation. This causes the veneer to drop onto the carrier 3. The pushers 4' connected to the lines 4 then push the veneer in a forward direction from left to right, as viewed in FIG. 1. The pushers 4 operate to pick up the newly delivered veneer from the carrier 3 and push it on top of the already complied veneers located underneath the carrier 3.
In accordance with the instant invention the present method automatically complies a back veneer, a sub-core thereon, a corethereon, an upper sub-core thereon, and lastly, an upper surface veneer.
Referring to FIGS. 8 and 9, a plywood B composed of five veneers is placed on a belt conveyor 36 at the downstream end of the compiling conveyor 4. The plywood B is then conveyed forward until it engages a limit switch 36'. When the limit switch is engaged a slide conveyor 37 operates to advance the plywood B to a table lifter 40. At the same time as the advance of the slide conveyor 37 a catcher 39 advances. The catcher supports the top end of the plywood B. Operation of the slide conveyor 37 is terminated by contact of a limit switch 37-1 and a bar 37'. The slide conveyor then returns and during such movement operates a limit switch 37-2. Limit switch 37- 2 operates an air cylinder 38' for lifting a stopper 38. The operation of the air cylinder 38 is terminated by actuation of the limit switch 37-3. The return action of the catcher 39 occurs when the limit switch 37-2 is engaged. The plywood B is piled on the lifter table 40, the rear end thereof being arranged in orderly fashion by the stopper 38.
What is claimed is:
1. A method of producing plywood comprising a plurality of veneers including the steps of delivering a plurality of wood veneers from an equal number of stations to a main conveyor line, coating adhesive on the surface of all but one of the veneers as the veneers are delivered to the main conveyor line, pushing the veneers in a predetermined direction by pushers that run along the main conveyor line, and compiling the veneers on top of one another as they are pushed with the uncoated veneer uppermost in the pile, and wherein each wood veneer is initially positioned at the main conveyor line at a location directly above and spaced from the line so that the pushers engage the veneer to move it in the predetermined direction and compile it on top of any veneers already picked up by the pushers.
2. A method as in claim 1 including the step of transporting the adhesive coated veneers to the main conveyor line by a vacuum conveyor having numerous small heads coated with material which does not adhere to the adhesive coated veneer.
References Cited UNITED STATES PATENTS 2,353,789 7/ 1944 Schieman 117-72 3,297,174 1/ 1967 Letchworth 214-6 F UX 3,367,823 2/1968 Clausen et a1. ...'156-557 X 6 3,616,090 10/1971 Larson 156-563 X 2,890,675 6/1959 Cheever, Jr. l56562 X 2,772,197 11/1956 Kozdemba 144-309 R X 3,084,090 4/ 1963 Rambo et a1. 156-299 3,133,850 5/1964 Alenius 156-299 X 3,620,887 11/1971 Nelson 156-563 3,639,191 2/1972 B'eider et a1 161-56 X FOREIGN PATENTS 497,334 11/1953 Canada 156-563 OTHER REFERENCES The Journal of Teflon, vol. 1, No. 4, p. 7, Du Pont, Wilmington, Del., April 1960, TP 1180.17-16.
ALFRED L. LEAVI'IT, Primary Examiner T. E. BOKAN, Assistant Examiner US. Cl. X.R.
20 144-315 R; 156-563; 198-35; 214-6 F, 6 M