US3710760A

US3710760A - Method and/or apparatus for continuous production of 4-plywood

Info

Publication number: US3710760A
Application number: US00109469A
Authority: US
Inventors: W Hopping
Original assignee: Champion International Corp
Current assignee: Champion International Corp
Priority date: 1971-01-25
Filing date: 1971-01-25
Publication date: 1973-01-16
Anticipated expiration: 1990-01-16

Abstract

Conventional glue applicator rollers and associated doctor rolls including a detachable mechanism which imparts a reciprocal motion to the doctor rolls during the operation of the apparatus. The initial unequal spacing of the doctor rolls from the applicator rollers is maintained during operation with the result that the upper and lower surfaces of a veneer ply receive unequal glue coatings. Reciprocating the doctor rolls reverses the surface to which the greater amount of adhesive is applied as veneer plies pass through the applicator rollers, thus facilitating the continuous fabrication of 4-ply laminates with a strong balanced glue line.

Description

United States Patent [1 1 Hopping n1] 3,710,760 1 Jan. 16, 1973 [54] METHOD AND/OR APPARATUS FOR CONTINUOUS PRODUCTION OF 4- PLYWOOD [75] Inventor: William J. Hopping, Pocomoke City, Md.

[73] Assignee: Champion International Corporation 22' Filed: Jan. 25, 1971 [21] Appl. No.: 109,469

Related U.S. Application Data [62] Division of Ser. No. 769,216, Oct. 21, 1968, abandoned.

[52] U.S. Cl ..118/227, 118/262 [51] ..B05c U112 [58] Field of Search ..118/224, 227, 228, 262

[56] References Cited UNITED STATES PATENTS 2,775,953 1/1957 McFall ..118/262 X 3,279,426 10/1966 Atkins et al. ..118/227 1,202,337 10/1916 Whitney et al.

1,661,174 3/1928 Francis 2,359,904 10/ l 944 Fluckinger ..l 18/227 Primary'ExaminerJohn P. Mclntosh A tt0rneyl-leilman & Heilman [57] ABSTRACT Conventional glue applicator rollers and associated doctor rolls including a detachable mechanism which imparts a reciprocal motion to the doctor rolls during the operation of the apparatus. The initial unequal spacing of the doctor rolls from the applicator rollers is maintained during operation with the result that the upper and lower surfaces of a veneer ply receive unequal glue coatings. Reciprocating the doctor rolls reverses the surface to which the greater amount of adhesive is applied as veneer plies pass through the applicator rollers, thus facilitating the continuous fabrication of 4-ply laminates'with a strong balanced glue line.

8 Claims, 3 Drawing Figures PATENIEDJAHIBIHYS: 3.710.760

INVENTOR WILLIAM J. HOPP ATTO R NE Y.

VIII/114m? METHOD AND/R APPARATUS FOR CONTINUOUS PRODUCTION OF 4-PLYWOOD FIELD OF THE INVENTION This application is a division of Ser. No. 769,216 filed Oct. 21, 1968.now abandoned.

This invention relates to plywood articles and more specifically to an apparatus for forming 4-ply laminates.

Plywood is a well-known material which has found widespread use in many applications and industries, particularly the building construction industry. This material is essentially a laminate consisting of an odd number of veneers or plies glued over each other, usually with adjacent plies placed so that their grain direction is at 90. The laminated plies are conventionally joined in continuous production by a mechanism having glue applicators in the form of rollers which apply glue to the surfaces of the plies as they pass. Several plies are joined to the adhesively coated plies which form the central or core section and the plywood article isformed upon hardening of the glue.

There are several problems associated with the a'pparatus and processes normally employed in the industry for the continuous production of plywood. For example, only 3-ply or S-ply laminates can be efficiently produced on a continuous basis due to a variety of factors which must be considered. These may be explained as follows. Since adjacent plies must be glued together, one or more of the contiguous surfaces must have glue applied thereto. However, for the process to be efficient, it is preferable that only one of the surfaces have a glue coating provided that it is sufficient in quantity to impart the properstrength to the joint. But greater efficiency is achieved if both surfaces of a passing ply are given a glue coating by the applicator rolls simultaneously. Moreover, further processing difficulty is encountered when the requirement of a balanced glue line between all ply joints in a plywood article is considered. Such a balanced glue line is important since all joints must be of v comparable strength or the final product will have weak areas. Therefore, in order to satisfy all of these requirements, only an odd number of plies can be laminated by the conventional technique. Thus, in a 3-ply article the center piy or core has glue applied to both surfaces and the outer plies are not given a glue coating. ln a 5-ply laminate, the alternate inner plies are coated on both surfaces, while the remaining three plies are not provided with an adhesive. Obviously, a 4-ply laminate cannot be efficiently produced by this process since adjacent plies would each be coated and when they are joined, an excess quantity of glue would form in the joint thereby adversely affecting the quality of the product, and the cost thereof.

It is apparent, therefore, that there is a great need in the plywood manufacturing industry for an apparatus and a process which will enable a plywood article having an even number of plies to be efficiently produced. It is the primary object of this invention to provide such an apparatus.

SUMMARY OF THE INVENTION Broadly, the apparatus of the invention comprises applicator means preferably in the form of a pair of spaced rollers, retarding means positioned proximate and adjacent the applicator means for retarding the flow of adhesive material from the applicator rollers, and means for moving the retarding means toward or away from the applicator rollers to increase or decrease the flow of adhesive. in the operation of the apparatus, an adhesive material such as glue is continuously applied to the applicator rollers and veneer plies are passed between the rollers. As they pass, the plies are coated with the adhesive on the upper and lower surfaces. However, the variation in pressure on the applicator rollers due to the motion of the retarding means enables the quantity of adhesive flowing from the rollers to be controlled during the process. By altering the pressure cycle on each applicator separately, an unequal quantity of adhesive is applied to the upper and lower surfaces of a passing ply. Furthermore, by continuously reciprocating the retarding means out of phase with each other, the greater quantity of adhesive is applied to opposite surfaces of each succeeding ply passing through the applicator rolls. Thus, if the first ply is coated with twice as much adhesive on the upper surface as on the lower surface, the next ply will be coated with twice as much adhesive on the lower surface due to the out of phase reciprocating motion of the retarding means. The two surfaces with less adhesive can bereadily joined without an excess of adhesive occurring in the joint, and when two uncoated outer plies are added, a 4-ply laminate is effectively produced on a continuous basis.

More specifically, the apparatus of the invention comprises in addition to the spaced applicator rollers, a pair of cylindrical rolls tangentially spaced from the applicator rollers to act as retarding means, an inclined rack with at least one pinion movably connected thereto, gearing means secured between the pinion and the retarding rolls, an air cylinder joined to the rack, and means for activating the air cylinder. Upon activation, the air cylinder imparts motion to the rack and pinion and thus to the retarding rolls through the gears. An increase or decrease in spacing between retarding rolls and applicator rollers results from this motion and dispersal of the adhesive material to the passing plies is controlled as hereinbefore indicated. Means for disconnecting the rack, pinion and associated equipment are alsoincluded to thereby restore the apparatus to conventional operation, if desired.

The apparatus of the invention enables 4-ply laminates or multiples thereof 'to be continuously produced thereby satisfying a long standing industry wide problem. The continuous production is automatically effected by varying the thickness of the glue coating on each core ply and as above-explained, by reversing the surface to which the greater amount of glue is applied. In this manner, any two core plies can be stacked immediately without the necessity of flipping" one or the other to obtain the proper mating surfaces. The outer surfaces of the stacked laminates have the proper quantity of adhesive to bind uncoated plies to complete the plywood article. The plywood article so produced is characterized by having the same quantity of adhesive at the center joint as at the outer joints. This is accomplished by joining two half coated surfaces in the center and full coated surfaces at the outer joints.

DESCRIPTION OF THE DRAWINGS The invention will be more readily understood by referring to the drawing, wherein:

FIG. 1 is a front elevational view of the apparatus of the invention;

FIG. 2 is a side elevational view of the apparatus shown in FIG. 1; and

FIG. 3 is a pictorial view, partly in section, of a 4-ply plywood article.

Referring to the drawing, there is shown in FIG. 1 an apparatus which is capable of mass producing 4-ply laminates. The apparatus 10 comprises

applicator rollers

12, 14 which rotate in the directions indicated by the arrows. A veneer ply 16 is passed between

rollers

12, 14 such that its surfaces are contacted by the rollers as they pass therebetween. An adhesive material such as glue is continuously supplied to the rollers such as by passing roller 14 through glue bath 18 and roller 12 through glue bath 20. Retarding means in the form of

doctor rolls

22, 24 are positioned proximate and

adjacent applicator rollers

12, 14, respectively, and form gaps therewith such as at 11,- 13. The size of the gaps is inversely related to the quantity of adhesive material which flows from the applicator rollerstothe veneer ply. The size of each gap is regulated and varied by means comprising a rack 26,

pinions

28, 30 and

worm gears

32, 34. A shaft 36 is connected to rack 26 through pin 38 and directly to air cylinder 40. A valve 42 controls the operation of the cylinder 40 and is manually operated by foot pedal 44. Rack 26 is partially supported by cam follower 48 during its movement. i

In the operation of the apparatus, the doctor rolls 22, 24 are initially adjusted such that one is closer to the applicator roller than the other. As shown clearly in FIG. I, doctor roll 22 is closer to roller 12 than doctor roll 24 isto roller 14. Therefore, as veneer ply 16 passes between the rollers, less adhesive is applied to the upper surface of the veneer due to the small gap 11 between doctor roll 22 and applicator 12. Both surfaces of the veneer ply are coated with an adhesive, but

because of the variation in gap size, the upper surface is provided with a coating about one-half the thickness of the lower surface. As the ply 16 passes through the applicator rollers, another similar ply (not shown) is fed to the rollers. Just prior thereto, an operator presses foot pedal 44 which activates valve 42 to pass air through air tube 46 and thereby operate air cylinder 40. The shaft 36 which is essentially an extension of the piston within the air cylinder, moves toward the air cylinder and causes rack 26 to also move in the same direction. As a result, pinions 28, 30 are rotated by the movement of the rack and the motion is translated through the worm gears 32, 34 to the doctor rolls 22, 24. As shown, the pinions rotate in opposite directions and thus the motion of the doctor rolls in a horizontal plane (as shown by the arrows) is such as to withdraw the upper doctor roll 22 from applicator roller 12 and to extend lower doctor roll 24 toward applicator roller 14. As a result, gap 11 is enlarged and gap 13 is reduced. Thus,the next ply through the rollers receives a thicker coating on the upper surface. Thisply is automatically placed on top of the previous ply,-the two thin or half coated surfaces being joined without flipping either ply. Two uncoated plies are then placed contiguously with the joined plies and a 4-ply laminate is readily formed. While the laminate is being formed, other veneer plies are passed through the coating apparatus so that continuous production of 4-ply plywood can be effected. In order to reverse the surface to which the greater amount of adhesive is applied, foot pedal 44 is pressed each time a ply is about to enter the applicator rollers. By this action, air cylinder 40 alternately receives and releases air through air tube 46 and valve 42. Shaft 36 and rack 26 consequently oscillate thereby imparting a reciprocal motion to the doctor rolls. Because of the arrangement of the rack and pinions, the doctor rolls are caused to reciprocate out of phase with each other and in this manner, unequal adhesive coatings are continuously supplied to the surfaces of passing plies.

The gaps 11, 13 are set initially such that one approximately twice the size of the other. This relation is maintained throughout the operation of the apparatus by proper design of the rack, pinion and air cylinder stroke. By employing pinions of the same size, for example, doctor rolls 22, 24 are caused to travel the same distance toward or away from the applicator rolls as the rack travels longitudinally. By proper selection of the air cylinder, that is, of the length of the piston strokes, the rack moves a distance sufficient to maintain the initial gap size each time the air cylinder is actuated. Therefore, each passing ply always receives twice as much adhesive on one surface as on the other. Of course, adjustments can be made to vary the ratio as required.

It is to be noted that pin 38 can easily be removed to disconnect the shaft 36 and air cylinder 40 from rack 26. The rack may then be removed entirely from the apparatus and doctor rolls 22, 24 reset to form equally spaced gaps. The apparatus is then capable of continuously producing 3-ply or S-ply laminates-in a conventional manner. Thus by a simple attachment and adjustment, a conventional glue coating machine is con-' verted to a 4-ply producing mechanism.

FIG. 3 illustrates a 4-ply plywood laminate formed by the process and apparatus of the invention. As there shown, veneer plies 50, 52 are provided with glue coatings while the outer plies 54, 56 have no glue thereon prior to forming the plywood article. Veneer ply 52 has an adhesive coating 58 on the upper surface which is about twice as thick as coating 60 on the lower surface while veneer ply 50 has a thin coating 62 on its upper surface and twice as much coating 64 on the outer plies may also be used. Any other combination of plies, all plies having the same or different thicknesses,

may also be used.

Initial individual adjustments of doctor rolls 22 and 24 for a half or a full coat is accomplished by reference guide lines on

pinions

28 and 30 before the rack 26 is Y positioned to engage the pinions. Obviously any conventional means, such as-a key or turn wheel, can be used to adjust these pinions for either a special 4-ply, or regular 3, 5 or 7-ply construction.

A simultaneous relative adjustment can be made by sliding rod 36 further into, or not as far into, the partially hollowed out rod 26 before tightening the screw 38. Alternatively, rack 26 could be extended through reciprocating air cylinder 40 and fastened therein by a detachable pin or bolt 26 at the lower end thereof. Hence, for a regular 3-ply operation, i.e., a single core ply having equal thicknesses of glue on each side of the core, the pin 26 is pulled out, the rack 26 moved away and out of engagement with the pinions, and the doctor rolls adjusted for equal quantities of coatings.

From the foregoing, it will be appreciated that the process and apparatus of the invention satisfy an industry wide need for a means and method of continuously producing 4-ply plywood articles of excellent quality and balanced strength. Many modifications of the apparatus disclosed are intended to be within the purview of this invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An apparatus for providing an adhesive coating of jacent to said applicator means for forming first and second gaps with said applicator means, said adhesive material being caused to pass through said gaps before being applied to said wood ply;

c. A first control means for adjusting the size of the gap between the first retarding means and the first applicator;

d. a second control means for adjusting the size of the gap between the second retarding means and the second applicator;

e. Means for simultaneously moving said first and second control means to increase the size of either gap while decreasing the size of the other gap.

2. An apparatus according to claim 1 wherein said first and second applicators are cylindrical rolls.

3. An apparatus according to claim 1 wherein said first and second retarding means are cylindrical rolls.

4. An apparatus according to claim 1 wherein said means for simultaneously moving said first and second control means comprises a gear means terminated in a imparts a continuous out of phase reciprocal motion to said retarding means.

8. An apparatus according to claim 4 wherein said rack is coupled to an air cylinder piston, and valve means coupled to the cylinder for actuating the cylinder piston.

I UNTKED STATES PATENT OFWCE .QEEHFECAESE @F RREHN 39710 760 Dated fianuary 1 1973' Patent No.

William J. Ho ping Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Tee title of the invention should read Method end/or Apparatus for Continuous lrouetion of i-Plv Plywood Signed and sealed this 29th day of May 1973.

EDWARD M.FLETCHER ,JR. I

Commissioner of Patents Attesting Officer FORM 304050 (10'69) USCOMM-DC 60376-P69 [1.5. GOVERNMENT FRINTIING OFFICE I 969 Q356"334

Claims

1. An apparatus for providing an adhesive coating of varying thicknesses to wood plies, comprising; a. a first and second applicator means having a space therebetween for passing wood plies therethrough, said applicator means having an adhesive material in contact therewith. b. a first and second retarding means positioned adjacent to said applicator means for forming first and second gaps with said applicator means, said adhesive material being caused to pass through said gaps before being applied to said wood ply; c. A first control means for adjusting the size of the gap between the first retarding means and the first applicator; d. a second control means for adjusting the size of the gap between the second retarding means and the second applicator; e. Means for simultaneously moving said first and second control means to increase the size of either gap while decreasing the size of the other gap.

4. An apparatus according to claim 1 wherein said means for simultaneously moving said first and second control means comprises a gear means terminated in a pinion gear in mesh with a rack.

5. An apparatus according to claim 4 wherein said rack is longitudinally adjustable for simultaneous control of each of said retarding means.

6. An apparatus according to claim 4 wherein said rack is adjustable over a distance which varies the gap size ratios from two-to-one to one-to-two.

7. An apparatus according to claim 4 wherein a relative movement between said rack and the gear means imparts a continuous out of phase reciprocal motion to said retarding means.