US3795470A

US3795470A - Press for continuously producing chip board, fiber board or the like

Info

Publication number: US3795470A
Application number: US00261668A
Authority: US
Inventors: Mets A De
Original assignee: Mets Nv Konstruktienerkhuizen
Current assignee: De Mets Nv Konstruktienerkhuizen be; Mets Nv Konstruktienerkhuizen
Priority date: 1971-07-14
Filing date: 1972-06-12
Publication date: 1974-03-05
Anticipated expiration: 1991-03-05
Also published as: DE2135230B2; CA972275A; JPS5639626Y2; SU415856A3; DE2135230A1; JPS5585824U; DD101332A5; ES404737A1; CH552462A; GB1393164A; FR2142546A5; IT961374B; SE376569B; AT321556B

Abstract

A press for continuously producing fiber board, chip board or the like comprising an upper and a lower endless link chain each traveling between a pair of guide rollers rotatable in one direction about parallel horizontal axes, each of said chains consisting of rigid link plates each pivotably connected to the adjacent plates, an endless feed belt surrounding each chain and traveling therewith, a plurality of pressure rollers acting upon the link plates of the inner stringers of both chains, and adjustable hydraulic or pneumatic pressure means acting at least upon each pressure roller for the upper chain, each link plate as seen in the direction of its travel having a length equal to at least twice the distance between the axes of two adjacent pressure rollers of the same chain so that each link plate of each inner chain stringer will be acted upon by the pressure of at least two adjacent pressure rollers.

Description

United States Patent 1191 De Mets Mar.5, 1974 [75] Inventor: Albert De Mets, Roeselare, Belgium [73] Assignec: De Mets N.V.

Konstruktienerkhuizen, Klaasterstraat, Kachtem, Belgium [22] Filed: June 12, 1972 21] Appl. No.: 261,668

[30] Foreign Application Priority Data July 14, 1971 Germany 2135230 [52] US. Cl 425/371, 100/151, 264/109,

[51] Int. Cl. B29c 15/00 [58] Field of Search... 425/335, 338, 371, 115, 130; 264/109, 112, 113, 122; 100/151, 153, 116, 118

Caughey 425/371 X Soda et al. 425/317 X Mallett ct al. 425/115 X Primary ExaminerRobert L. Spicer, Jr. Attorney, Agent, or FirmCraig and Antonelli [57] ABSTRACT A press for continuously producing fiber board, chip board or the like comprising an upper and a lower endless link chain each traveling between a pair of guide rollers rotatable in one direction about parallel horizontal axes, each of said chains consisting of rigid link plates each pivotably connected to the adjacent plates, an endless feed belt surrounding each chain and traveling therewith, a plurality of pressure rollers acting upon the link plates of the inner stringers of both chains, and adjustable hydraulic or pneumatic pressure means acting at least upon each pressure r01- ler for the upper chain, each link plate as seen in the direction of its travel having a length equal to at least twice the distance between the'axes of two adjacent pressure rollers of the same chain so that each link plate of each inner chain stringer will be acted upon by the pressure of at least two adjacent pressure rollers.

35 Claims, 3 Drawing Figures PRESS EOR CONTINUOUSLY PRODUCHNG CHEF BOARD, FHBER BOARD OR THE LHKIE The present invention relates to a continuously operating press for continuously producing chip board, fiber board or the like of a mixture of fibrous material such as wood chips, fibers, cellulose or similar materials and suitable binders. This press is of the type which comprises an upper and a lower endless belt each of which forms a link chain the individual links of which consist of rigid steel plates which are pivotally connected to each other at their longitudinal ends. These two chains are movable around and are tightened longitudinally by guide wheels, preferably of a polygonal peripheral shape, which are rotatable in the same direction about horizontal parallel axes. The stringers of these chains facing each other between which the material is to be compressed are movable along pressure rollers which are rotatably mounted between the upper and lower stringers of each chain. The pressure rollers on the link plates at least of the upper chain are acted upon by the controlled but variable pressure of hydraulic or pneumatic cylinder-'and-piston units which press these rollers in the direction toward the opposite pressure rollers of the lower chain and the link plates thereof. One or more of. these pressure rollers of both chains are connected to drive means for driving the chains at the same speed.

Presses of the type as above described have been previously designed so as to act as so-called preliminary presses for merely compressing the loose material to a certain thickness which is thereafter passed to at least one further press in which the fiber or chip board is further compressed to the desired final thickness and heated so as to set and harden the binder of the mate rial.

' Prior to the disclosure of a press as above described another type of press, a so-called caterpillar-chain press, has been disclosed for continuously producing chip board or the like under pressure or under pressure and heat. in such a press, a layer of wood chips, saw dust or other comminuted fibrous or cellulose material which is mixed with a suitable binder is at first compressed within a short compression stage between the link plates of two chains to the desired final thickness of the board to be produced and it is then maintained under a uniform pressure so as to prevent any swelling of the material while being set and hardened. Within the compression stage, the link plates of one chain are guided along a curved path which has such a radius of curvature that the upper and lower endless metal belts which are disposed between the two chains will not be damaged by being bent when passing around their guide rollers or guide drums or within the compression stage in which the adjacent link plates abut at an angle upon each other while pressing upon the endless belts. During the subsequent setting stage, all link plates of each of the two chains are disposed within a common straight plane and the adjacent plates of each chain are separated from each other by slots of such a narrow width that the metal feed belt of the material while running in a straight direction covers or bridges this slot and will be concavely bent only to an insignificant ex tent. During the curved section of the travel of the two chains, however, the slots between the adjacent link plates are widened to such an extent that the steel belts bridging the slots with a concave curvature within the compression stage will still remain within the elastic limits of the metal and will withstand the pressure which is exerted upon these belts. As compared with the continuously operating presses at first mentioned above, these so-called caterpillar-chain presses have particularly the disadvantage. that the endless chains have to be driven solely by the sprocket wheels at the opposite ends of the press on which each chain is guided so as to reverse the direction of travel of its two stringers. Considering the high rate of compression and solidity which are nowadays required of most fiber or chip board or the like, such caterpillar-chain presses would have to be made of such a great length that very high forces would be required for driving the sprocket wheels and excessive tensions would occur within the chains causing them to break within a short time.

The presses as first described have the advantage over these catepillar-chain presses that they may be made of any desired length since the endless plate-link chains are not merely driven by their guide wheels, but primarily by at least some of the pressure rollers which act upon the inner stringers of the two chains, that is, the stringers which face each other. If such a press should have a great length, it is merely necessary to provide means for positively driving a larger number or all of the pressure rollers. These presses have, however, the disadvantage that, since each rigid link plate of the two chains is acted upon only by one pressure roller, it has the tendency to tilt relative to the adjacent link plates. Since the length of the individual link plates of the two chains is necessarily limited and the diameter of the pressure rollers had to be made relatively large in order to be able to transmit a sufficient pressure upon the link plates, it was unavoidable that the finished fiber or chip board when thus continuously produced had small transverse projections or recesses at more or less uniform distances on its upper and lower sides. These projections or recesses could not be avoided because it occurred very often that a link plate was acted upon at the same time only by a single pressure roller, and especially if in the travel of the chains the pressure was exerted only upon one end part of a link plate, the plate would tilt relative to the intended plane. This tilting also caused an excessive strain upon the link pins which pivotally connect the adjacent link plates to each other.

It is an object of the present invention to improve a continuously operating press of the type as first described above so as to eliminate the possibility that undesirable deformations of the chip or fiber board or the like might occur during its production and also so as to prevent the individual link plates of the two chains from being bent and an excessive strain from being exerted upon the entire chains and upon the link pins or the like which pivotably connect the adjacent link plates of the two chains to each other. An additional object of the invention is to provide suitable means for preventing the pressure rollers from being bent under the pressure which is exerted on their ends by hydraulic or pneumatic units.

For attaining these objects, the invention provides that each link plate of the two chains has a length equal to at least twice the distance between the axes of two adjacent pressure rollers acting upon each chain. Thus, when the press is in operation to produce fiber or chip board or the like continuously, each link plate of each chain while passing through the compression and setthe adjacent link plates. This also permits the individual pressure rollers to be made of a considerably smaller diameter, for example, a diameter of one half or less than that which was previously required, the hydraulic or pneumatic forces which have to be exerted upon the individual pressure rollers may be considerably lower and be more accurately controlled and the link plates do not have to be as thick, heavy and solid as they had to be when each link plate was acted upon only by one pressure roller. Furthermore, due to the larger number of pressure rollers and also the larger number of these rollers which are positively driven, the endless feed belts which travel along with and around the link plate chains and then directly between the inner stringers of these chains for feeding the loose fibrous material continuously toward and between these stringers and for then transmitting the pressure which is exerted by the pressure rollers upon these inner chain stringers and through the latter during the compression and setting stages upon the opposite sides of the fibrous material will not be subjected to very high stresses and may therefore consist of relatively thin and flexible belts of steel, plastic, andsuitable fabric, netting, or the like. Furthermore, the wearing plates which were required in some of the known continuously operating presses betwen the pressure rollers and the like plates may now be omitted entirely.

Since the pressure rollers which act directly upon the inner chain stringers may now be made of relatively small diameters, it is advisable according to the invention to brace at least some of these rollers intermediate their ends, and especially those rollers which determine the final thickness of the fiber or chip board so as to prevent them from bending between theirends which are mounted in bearings and also so as to reduce the stresses and the wear to which these bearings are subjected. These bracing means preferably consist of smaller rollers which act upon the main pressure rollers at least centrally of their length and, in turn, are acted upon by hydraulic or pneumatic units similar to those which act at least upon the upper pressure rollers. Even if only the bearings of the upper main pressure rollers are vertically slidable and acted upon by such pressure units,'while the bearings of the lower pressure rollers are mounted in fixed positions, the bracing rollers should also be provided for all those lower pressure rollers which are vertically opposite to the upper pressure rollers which are supported by such bracing rollers. If only the upper or lower pressure rollers would thus be supported, the stresses and wear upon the bearings of the opposite unbraced rollers might become excessive. On all those pressure rollers on which such bracing rollers are required or desirable, these bracing rollers are preferably provided in pairs at equal distances from the vertically longitudinal plane of the respective pressure roller so that, as seen in cross secion, this pressure roller will have a uniform three-point support by the lines of engagement with the two bracing rollers and the line of its engagement with the respective link plate of the upper or lower chain.

The features and advantages of the present invention will become further apparent from the following detailed description thereof, which is to be read with reference to the accompanying diagrammatic drawings, in which FIG. 1 shows a side view of the press according to the invention, some outer parts of which are broken away to show the inside of the press;

FlG. 2 shows a cross section which is taken along the line ll ll of HG. 1; while FIG. 3 shows a cross section which is taken along the line lll ill of FIG. 2.

As illustrated in the drawings, the press according to the invention essentially consists of two frames 1 and 2 on each of which an endless link chain 3 or 4 is mounted which is composed of

link plates

19 or 20, respectively, which are of equal length and are pivotably connected by link pins or hinges to each other. Each of these chains is surrounded by an endless feed belt 7 or 8, respectively, which preferably consists of thin fexible steel, but may also consist of plastic or a suitable fabric or a screen material. The inner stringers of the chains 3 and 4, that is, those facing each other, directly engage upon the corresponding parts of the belts 7 and 8 and are adapted to take along and drive these belts at the same speed. Chains 3 and 4 and belts 7 and 8 are mounted so that between the sides of the belts which are directly acted upon by the opposite chain stringers 19 and 20 a slot is formed in which a layer 21 of chips, fibers or the like is compressed between the belts 7 and 8 to form a chip or fiber board of a certain but adjustable thickness. Each of the opposite end parts of belt 7 is movable along guide rollers 7 the axes of which are disposed substantially within a semicircle, and the right end part of the lower belt 8 is similarly movable along guide rollers 8, while the left end part of the lower belt 8 which also serves for feeding the layer 21 of fibers or chips to the press is guided by a guide drum or by similar guide rollers which are not shown in the drawings since for this feeding movement of the lower belt 8 toward and into the press, they are spaced at a certain distance from the press as shown in FIG. 1. Since the

links

19 and 20 of the two chains 3 and 4 consist of rigid plates, the guide wheels 13, 14 and 15, 16 for these chains which are mounted on parallel horizontal shafts 9, 1t) and ll, 12, respectively, are made, for example, of a hexagonal shape and each straight outer surface of each of these guide wheels l3 to 16 has a length substantially corresponding to the distance between the link pins or the like which connect each chain link to the adjacent links of the same chain.

The inner stringers 5 and 6 of the two chains 3 and 4 are pressed toward each other by

pressure rollers

17 and 18 which also drive the two chains and the belts 7 and 8 thereon and are rotatably mounted in corresponding positions opposite to each other so as to engage upon the upper side of the stringer 5 of the upper chain 3 and the lower side of the stringer 6 of the lower chain 4, respectively. While the lower pressure rollers 18 may be rotatably mounted in fixed bearings and their axes are disposed within a common horizontal plane, the bearings of each of the upper pressure rollers 17 are connected to and preferably mounted on and vertically movable by adjustable hydraulic or pneu' matic cylinder-and-piston units. A certain number of these upper pressure rollers 17 at the inlet side of the machine, for example, the rollers 17a to 1711, form a compression stage in cooperation with the opposite lower rollers 18 by being controlled so that each of these rollers exerts a higher pressure upon the inner stringer 5 of the upper chain 3 than the preceding roller so as to effect a successive compression of the layer 21 of fibers, wood chips, or the like until it has the final thickness of the fiber or chip board which is to be produced. The subsequent upper pressure rollers 17 together with the opposite lower rollers 18, the intermediate inner stringers 5 and 6 of chains 3 and 41 and the intermediate parts of belts 7 and 8 form the setting stage of the machine, that is, the stage in which the binder in the previously compressed fibrous material is set and hardened. These subsequent upper pressure rollers 17 are movable by their hydraulic or pneumatic units toward these lower rollers 18 only so far that the slot between the parts of the belts 7 and 8 subsequent to the compression stage will have a uniform thickness and the surfaces of these belt parts will extend parallel to each other up to the outlet end of the machine from which the fiber or chip board is delivered.

As may be seen in FIG. 1, the diameters of the

pressure rollers

17 and 18 are made of such a size that during the travel of the two chains 3 and 4 each

link plate

19 and 20 of these chains will engage with and be acted upon by at least two laterally

adjacent pressure rollers

17 and 18, respectively. Each

link plate

19 and 20 therefore has a length equal to at least twice the distance between the axes of two adjacent pressure rollers 17 or' 18, respectively. Consequently, each

link plate

19 and 20 will at all times be acted upon by the pressure of at least two upper pressure rollers 17 and two lower pressure rollers 18, respectively.

For setting the binder in the fiber or chip layer 21 after it has been compressed to its final thickness, for example, by the pressure rollers 17a to 17d, the outer stringers of the two link chains 3 and 4 are adapted to be heated by suitable heating means, for example, by

gas burners

22 and 23. In addition, the endless belts 7 and 8 surrounding the link chains 3 and 4 may be heated, for example, by electric heating plates 24 and 25.

FIG. 2 illustrates a pair of

opposite pressure rollers

17 and 18 of the setting stage of the pressure subsequent to the pressure rollers 17a to 17d of the compres sion stage. These rollers are rotatably mounted in

bearings

26, 27 and 28, 29, respectively. For preventing all

pressure rollers

17 and 18 from bending between their ends which are mounted in the bearings 26 to 29, or from tilting out of a horizontal plane, each upper and

lower pressure roller

17 and 18 is supported at the center of its length by a pair of bracing

rollers

30 and 31 or 32 and 33, respectively, as shown in FIGS. 2 and 3 but not visible in H6. 1. These bracing rollers are rotatably mounted in

bearings

34' and 35 or 36 and 37, respectively, which, in turn, are mounted on the

piston rods

38 or 39 of hydraulic 0r pneumatic units the cylinders of which are mounted on fram e 1 or frame 2, respectively. These units are therefore controlled so that the line of engagement of each

pressure roller

17 or 18 with the respective link plate 19 or 211 will at all times be straight and the opposite sides of the slot between the parts of belts 7 and 8 on the

link plates

19 and 20 upon which the respective pressure rollers act will always be parallel to each other, as seen in the direction of the length of each pressure roller. Suitable adjustable control means, not shown, should also be provided for the hydraulic or pneumatic units acting upon the bracing

rollers

30 and 31 or 32 and 33 and upon the

bearings

26 and 27 of

eachpressure roller

17 or 18 for insuring that the finished fiber or chip board delivered by the machine will have the desired uniform thickness.

As shown in FlG. 2, it may be advisable, especially if the machine according to the invention forms a final press, to provide equal but exchangable spacing bars 40 between the

bearings

26 and 27 of each upper pressure roller 17 and the bearings 28 and 29! of the corresponding lower pressure roller 18 of the entire setting stage of the press which follows the compression stage which is formed, for example, by the pressure rollers 17a to 17d and the corresponding lower rollers 13. As further indicated diagrammatically in PEG. 2, some or all of the upper and

lower pressure rollers

17 and 18 of the compression and setting stages may be driven by being connected by drive shafts 42 and 43 to a common gear unit 41. Of course, the individual pressure rollers may also be driven by separate drive means which are properly synchronized with each other.

Although my invention has been illustrated and described with reference to the preferred embodiment thereof, 1 wish to have it understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is: v

1. A press for continuously producing fiber board, chip board or the like comprising an upper and a lower endless link chain, each of said chains being movable around and between guide rollers or the like rotatable in one direction about horizontal parallel axes, and each link chain consisting of a plurality of rigid link plates of a uniform length each of which is pivotably connected at its longitudinal ends to the adjacent link plates, an endless feed belt extending around each chain, said belt being acted upon and adapted to travel with the link plates of the inner stringers of said chains facing each other, a plurality of pressure rollers rotatable about horizontal parallel axes between the inner and outer stringers of each chain, said axis of each pressure roller associated with one chain being disposed within a vertical plane extending through the axis of a pressure roller associated with the other chain, adjustable pressure means acting upon said pressure rollers associated with said inner stringer at least of one of said chains for pressing the link plates of said stringer and said feed belt thereon toward the other feed belt and the link plates of the inner stringer of the other chain, and means for synchronously driving at least some of said pressure rollers acting upon said link plates of said inner stringers of both chains and for thereby synchronously driving said inner stringers and said belts thereon, each of said link plates having a length at least equal to twice the distance between the axes of two adjacent pressure rollers acting upon the same chain.

2. A press as defined in claim 1, further comprising means for heating at least said chains for. setting and hardening the materials of said board after being compressed to its final thickness.

3. A press as defined in claim 1, in which the ends of all of said pressure rollers are rotatably mounted in bearings, said bearings of said pressure rollers associated with the inner stringer of at least a first of said chains being adapted to be acted upon and to be moved by said pressure means in the direction toward and away from the bearings of the opposite pressure rollers associated with the inner stringer of the second chain,

a plurality of said pressure rollers adjacent to each other near the inlet end of said press which are associated with said inner stringers of said two chains and the endless belt thereon forming a compression stage for compressing a loose layer of the materials of which said board is composed substantially to the desired final thickness of said board, and a plurality of said pressure rollers subsequent to those near said inlet end and asso ciated with said inner stringers of said two chains and the endless belts thereon forming a heat-setting stage for setting and hardening said board at its final thickness, and means for heating at least said inner stringers at least within said setting stage.

4. A press as defined in claim 3, further comprising means for also heating said endless belt at least within said setting stage.

5. A press as defined in claim 3, further comprising means for bracing at least the central part of the length of all of said pressure rollers at least of said setting stage so as to prevent said rollers from bending.

6. A press as defined in claim 5, in which said bracing means comprise a pair of bracing rollers rotatably mounted and engaging upon the periphery of at least the central part of each of said pressure rollers of both stages at equal distances from a vertical plane extending through the line of engagement of said pressure roller with said inner stringer of the associated chain and also of the engagement of the opposite pressure roller with said inner stringer of the other chain, and adjustable pressure means acting upon said bracing rollers with a pressure substantially in conformity with the pressure to which said bearings of said pressure rollers are subjected.

7. A press for continuously producing boards such as chipboards, fiberboards, and the like; said press comprising:

a first endless chain formed of a plurality of link plates hingedly connected to one another at the ends thereof;

a second endless chain formed of a plurality of link plates hingedly connected to one another at the ends thereof;

guiding and moving means for guiding and moving said first and second chains with respective outer surfaces of said chains in facing relationship and moving in the same direction over a material pressing portion of the respective travel paths of said chains such that board material for forming said boards can be conveyed by and compressed between said chains along said material pressing portion of said respective travel paths; and

pressure applying means for pressing said chains toward one another along said material pressing portion of the respective travel paths of said chains such that board material may be forcefully compressed between said chains, said pressure applying means including a plurality of pressure rollers arranged inside of the travel path of at least one of said chains and forcing means for forcing said pressure rollers against the link plates of said at least one chain;

wherein said guiding and moving means includes drive means for rotatably driving at least one of said pressure rollers such that said at least one of said pressure rollers applies moving forces to said link plates to move said at least one of said chains along its respective travel path.

8. A press according to claim 7, further comprising a first flexible feed belt enclosing a portion of and movable with said first chain and a second flexible feed belt enclosing a portion of and movable with said second chain, wherein said first and second belts are interposed between said chains over said material pressing portion of the respective travel paths thereof to directly engage said board material during pressing operations.

9. A press according to claim 8, wherein each of said first and second belts are endless belts which com pletely surround the respective first and second chains.

10. A press according to claim 7, wherein said pressure applying means includes a plurality of pressure rollers inside each of said chains, wherein said forcing means includes means for forcibly moving the pressure rollers inside of said first chain in a direction transverse to the direction of travel of said chains, and wherein the pressure rollers in said second chain are maintained in a relatively fixed position for rotation about respective roller axes extending transverse to the direction of travel of said chains.

ll. A press according to claim l0, wherein the pressure rollers in said first chain are rotatable about re spective axes extending transverseto the direction of travel of said chains, and wherein each of said pressure rollers in said first chain are constrained to move with their respective axes movable in a plane which also contains the axis of a respective one of said pressure rollers in said second chain.

12. A press according to claim 1 1, wherein said drive means includes means for synchronously driving respective oppositely-facing pressure rollers in said first and second chains.

13. A press according to claim 12, wherein said drive means includes means for driving a plurality of pressure rollers in each of said chains.

14. A press according to claim 12, wherein said forcing means includes separate piston and cylinder means for each of said pressure rollers in said first chain, and wherein control means are provided for controlling said piston and cylinder means to sequentially compress the board material with continuously decreasing distance between said chains along a first part of said material pressing portion of said respective travel paths and to maintain a fixed distance between said chains along the part of said material pressing portion of said respective travel paths which follows said first part.

15. A press according to claim 7, wherein said forcing means includes separate piston and cylinder means for each of said pressure rollers in said first chain, and wherein control means are provided for controlling said piston and cylinder means to sequentially compress the board material with continuously decreasing distance between said chains along a first part of said material pressing portion of said respective travel paths and to maintain a fixed distance between said chains along the part of said material pressing portion of said respective travel paths which follows said first part.

16. A press according to claim 14, wherein said drive means includes means for driving a plurality of pressure rollers in each of said chains.

17. A press according to claim 16, wherein said guiding and moving means includes two-spaced reversing guide wheels for each chain, wherein said material pressing portion of said respective travel paths extends between said reversing guide wheels, and wherein each of said pressure rollers is spaced from said guide wheels. 7 v

18. A press according to claim 7, wherein said guiding and moving means includes two-spaced reversing guide wheels for each chain, wherein said material pressing portion of said respective travel paths extends between said reversing guide wheels, and wherein each of said pressure rollers is spaced from said guide wheels.

19. A press for continuously producing boards such as chipboards, fiberboards, and the like, said press comprising:

guiding and moving means for'guiding and moving said first and second chains with respective outer surfaces of said chains in facing relationship and moving in the same direction over a material pressing portion of the respective travel paths of said chains such that board material for forming said boards can be conveyed by and compressed between said chains along said material pressing portion of said respective travel paths;

and pressure applying means for pressing-said chains toward one another along said material pressing portion of the respective travel paths of said chains such that board material may be forcefully compressed between said chains, said pressure applying means including aplurality of pressure rollers arranged inside of the travel path of at least one of said chains and forcing means for forcing said pressure rollers against the link plates of said at least one chain;

wherein said pressure rollers are rotatable about respective axes extending transverse to the direction of travel of said chains, and wherein back-up support means are provided intermediate the ends of at least some of said rollers, said back-up support means including means for applying an adjustable pressure against said rollers separate from the forces applied against said rollers by said forcing means.

20. A press according to claim 19, wherein said guiding and moving means includes drive means for rotatably driving at least one of said pressure rollers such that said at least one of said pressure rollers applied moving forces to said link plates to move said at least one of said chains along its respective travel path.

21. A press according to claim 19, wherein said pres sure rollers are rotatably supported in bearing means at respective opposite ends of said pressure rollers, and wherein said forcing means include piston-cylinder means for moving said bearing means.

22. A press according to claim 21, wherein said backup support means includes at least one rotatable member engageable, respectively, with the surface of each of said at least some of said rollers at a position intermediate said bearing means.

23. A press according to claim 22, wherein said backup support means includes piston-cylinder means separate from the forcing means for adjustably moving each of said at least one rotatable members in a direction transverse to the respective axes of rotation of said rollers.

24. A press according to claim 23, wherein said backup support means includes a pair of rotatable members for each of said pressure rollers, the rotatable members of each pair being spaced circumferentially from one another around the respective pressure roller and being movable together by said piston-cylinder means for said back-up support means.

25. A press according to claim 24, wherein oppositely facing pressure rollers inside said first and second chains are provided with a pair of said rotatable members.

26. A press according to claim 23, wherein said rotatable members are rotatable about respective axes extending parallel to the rotational axes of said rollers.

27. A press according to claim 23, wherein said guiding and moving means includes drive means for rotatably driving at least one of said pressure rollers such that said at least one of said pressure rollers applies moving forces to said link plates to move said at least one of said chains along its respective travel path.

28. A press according to claim 9, further comprising a first flexible feed belt enclosing a portion of and movable with said first chain and a second flexible feed belt enclosing a portion of and movable with said second chain, wherein said first and second belts are inter posed between said chains over said material pressing portion of the respective travel paths thereof to directly engage said based material during pressing operations.

29. A press according to claim 28, wherein each of said first and second belts are endless belts which completely surround the respective first and second chains.

30. A press according to claim 20, wherein said pressure applying means includes a plurality of pressure rollers inside each of said chains, wherein said forcing means includes means for forcibly moving the pressure rollers inside of said first chain in a direction transverse to the direction of travel of said chains, and wherein the pressure rollers in said second chain are maintained in a relatively fixed position for rotation about respective roller axes extending transverse to the direction of travel of said chains.

31. A press according to claim 36, wherein the pressure rollers in said first chain are rotatable about respective axes extending transverse to the direction of travel of said chains, and wherein each of said pressure.

rollers in said first chain are constrained to move with their respective axes movable in a plane which also contains the axis of a respective one of said pressure rollers in said second chain.

32. A press according to claim 31, wherein said drive means includes means for synchronously driving respective oppositely-facing pressure rollers in said first and second chains.

33.. A press according to claim 32, wherein said forcing means includes separate piston and cylinder means for each of said pressure rollers in said first chain, and wherein control means are provided for controlling said piston and cylinder means to sequentially compress the board material with continuously decreasing distance between said chains along a first part of said material pressing portion of said respective travel paths and to maintain a fixed distance between said chains along the part of said material pressing portion of said respective travel paths which follows said first part.

34. A press according to claim 7, wherein the spacing between the rotational axes of adjacent pressure rollers in the direction of movement of the chains is less than the length of one of said link plates in said direction of movement of the chains to assure that at least two pressure rollers are in engagement with a link plate at all positions along said material pressing portion of the travel paths of said chains except the extreme end positions adjacent respective first and last pressure rollers in the direction of chain travel.

35. A press according to claim 19, wherein the spaclers in the direction of chain travel.

Claims

2. A press as defined in claim 1, further comprising means for heating at least said chains for setting and hardening the materials of said board after being compressed to its final thickness.

3. A press as defined in claim 1, in which the ends of all of said pressure rollers are rotatably mounted in bearings, said bearings of said pressure rollers associated with the inner stringer of at least a first of said chains being adapted to be acted upon and to be moved by said pressure means in the direction toward and away from the bearings of the opposite pressure rollers associated with the inner stringer of the second chain, a plurality of said pressure rollers adjacent to each other near the inlet end of said press which are associated with said inner stringers of said two chains and the endless belt thereon forming a compression stage for compressing a loose layer of the materials of which said board is composed substantially to the desired final thickness of said board, and a plurality of said pressure rollers subsequent to those near said inlet end and associated with said inner stringers of said two chains and the endless belts thereon forming a heat-setting stage for setting and hardening said board at its final thickness, and means for heating at least said inner stringers at least within said setting stage.

7. A press for continuously producing boards such as chipboards, fiberboards, and the like; said press comprising: a first endless chain formed of a plurality of link plates hingedly connected to one another at the ends thereof; a second endless chain formed of a plurality of link plates hingedly connected to one another at the ends thereof; guiding and moving means for guiding and moving said first and second chains with respective outer surfaces of said chains in facing relationship and moving in the same direction over a material pressing portion of the respective travel paths of said chains such that board material for forming said boards can be conveyed by and compressed between said chains along said material pressing portion of said respective travel paths; and pressure applying means for pressing said chains toward one another along said material pressing portion of the respective travel paths of said chains such that board material may be forcefully compressed between said chains, said pressure applying means including a plurality of pressure rollers arranged inside of the travel path of at least one of said chains and forcing means for forcing said pressure rollers against the link plates of said at least one chain; wherein said guiding and moving means includes drive means for rotatably driving at least one of said pressure rollers such that said at least one of said pressure rollers applies moving forces to said link plates to move said at least one of said chains along its respective travel path.

9. A press according to claim 8, wherein each of said first and second belts are endless belts which completely surround the respective first and second chains.

11. A press according to claim 10, wherein the pressure rollers in said first chain are rotatable about respective axes extending transverse to the direction of travel of said chains, and wherein each of said pressure rollers in said first chain are constrained to move with their respective axes movable in a plane which also contains the axis of a respective one of said pressure rollers in said second chain.

12. A press according to claim 11, wherein said drive means includes means for synchronously driving respective oppositely-facing pressure rollers in said first and second chains.

17. A press according to claim 16, wherein said guiding and moving means includes two-spaced reversing guide wheels for each chain, wherein said material pressing portion of said respective travel paths extends between said reversing guide wheels, and wherein each of said pressure rollers is spaced from said guide wheels.

19. A press for continuously producing boards such as chipboards, fiberboards, and the like, said press comprising: a first endless chain formed of a plurality of link plates hingedly connected to one another at the ends thereof; a second endless chain formed of a plurality of link plates hingedly connected to one another at the ends thereof; guiding and moving means for guiding and moving said first and second chains with respective outer surfaces of said chains in facing relationship and moving in the same direction over a material pressing portion of the respective travel paths of said chains such that board material for forming said boards can be conveyed by and compressed between said chains along said material pressing portion of said respective travel paths; and pressure applying means for pressing said chains toward one another along said material pressing portion of the respective travel paths of said chains such that board material may be forcefully compressed between said chains, said pressure applying means including a plurality of pressure rollers arranged inside of the travel path of at least one of said chains and forcing means for forcing said pressure rollers against the link plates of said at least one chain; wherein said pressure rollers are rotatable about respective axes extending transverse to the direction of travel of said chains, and wherein back-up support means are provided intermediate the ends of at least some of said rollers, said back-up support means including means for applying an adjustable pressure against said rollers separate from the forces applied against said rollers by said forcing means.

21. A press according to claim 19, wherein said pressure rollers are rotatably supported in bearing means at respective opposite ends of said pressure rollers, and wherein said forcing means include piston-cylinder means for moving said bearing means.

22. A press according to claim 21, wherein said back-up support means includes at least one rotatable member engageable, respectively, with the surface of each of said at least some of said rollers at a position intermediate said bearing means.

23. A press according to claim 22, wherein said back-up support means includes piston-cylinder means separate from the forcing means for adjustably moving each of said at least one rotatable members in a direction transverse to the respective axes of rotation of said rollers.

24. A press according to claim 23, wherein said back-up support means includes a pair of rotatable members for each of said pressure rollers, the rotatable members of each pair being spaced circumferentially from one another around the respective pressure roller and being movable together by said piston-cylinder means for said back-up support means.

28. A press according to claim 9, further comprising a first flexible feed belt enclosing a portion of and movable with said first chain and a second flexible feed belt enclosing a portion of and movable with said second chain, wherein said first and second belts are interposed between said chains over said material pressing portion of the respective travel paths thereof to directly engage said based material during pressing operations.

31. A press according to claim 30, wherein the pressure rollers in said first chain are rotatable about respective axes extending transverse to the direction of travel of said chains, and wherein each of said pressure rollers in said first chain are constrained to move with their respective axes movable in a plane which also contains the axis of a respective one of said pressure rollers in said second chain.

33. A press according to claim 32, wherein said forcing means includes separate piston and cylinder means for each of said pressure rollers in said first chain, and wherein control means are provided for controlling said piston and cylinder means to sequentially compress the board material with continuously decreasing distance between said chains along a first part of said material pressing portion of said respective travel paths and to maintain a fixed distance between said chains along the part of said material pressing portion of said respective travel paths which follows said first part.

35. A press according to claim 19, wherein the spacing between the rotational axes of adjacent pressure rollers in the direction of movement of the chains is less than the length of one of said link plates in said direction of movement of the chains to assure that at least two pressure rollers are in engagement with a link plate at all positions along said material pressing portion of the travel paths of said chains except the extreme end positions adjacent respective first and last pressure rollers in the direction of chain travel.