METHOD AND APPARATUS FOR JOINTING OR SEAMING AND LAMINATING LEVEL-SURFACED OBJECTS, SUCH AS VENEER LEAVES OR SHEETS OR OTHER WOODEN OBJECTS

Abstract: To achieve a high production capacity, the objects (10) are passed through a press (12) consisting of two pressing rollers in such manner that the objects are pushed edgewise together when they enter the press, where a fibrous reinforcement (13-15) or a coat of plastic is pressed at least to one side of the objects, said reinforcement or plastic coat being attached to the objects by glueing or smelting.

Description: METHOD AND APPARATUS FOR JOINTING OR SEAMING AND LAMINATING LEVEL-SURFACED OBJECTS, SUCH AS VENEER LEAVES OR SHEETS OR OTHER WOODEN OBJECTS The present invention relates to a method and apparatus for jointing or seaming and laminating level-surfaced objects, such as veneer leaves or sheets or other wooden objects. In current practice, veneer sheets are jointed by a method in which threads are glued to the underside of the sheets to hold them together. In another method currently used, glue is applied to the edges of the sheets to be joined, whereupon the sheets are pressed together using separate equipment. One of the worst drawbacks with these methods is that, employing several successive stages of operation, they are slow. The object of the present invention is to eliminate the drawbacks mentioned and provide a high-capacity production line for the manufacturing of elastic coating veneer. The method of the invention is characterized in that, for jointing or seaming objects together, the objects are passed through a press consisting of two pressing rollers, where the objects are pushed edgewise together and a fibrous reinforcement or a coat of plastic is pressed at least to one side of the objects, said reinforcement or plastic coat being attached to the objects by gluing or smelting. The method of the invention reduces the number of stages of operation and accelerates the jointing procedure, since it can be implemented as a continuous process. Moreover, the method of the invention makes it possible to produce continuous hides of pliable, durable and smooth-surfaced veneer. A preferred embodiment of the method of the invention is characterized in that the glue is applied onto the objects by first spreading it on a raster surface, from which it is then transferred to the areas on the surface of the object or fibrous reinforcement determined by the raster pattern. Another preferred embodiment of the method of the invention is characterized in that the objects are conveyed to the press on a belt which moves at a speed exceeding the speed of rotation of the pressing rollers. A third preferred embodiment of the method of the invention is characterized in that the preparatory treatment of the objects includes pressing the objects by means of a hydraulic press provided with heating means. The apparatus designed, for implementing the method of the invention is characterized in that the apparatus comprises at least one conveyor for moving the objects, at least one press consisting of two pressing rollers for pressing a fibrous reinforcement or a plastic coat at least on one side of the object, and a spreading device for spreading the glue or a heating device for heating the glue or the plastic foil. A preferred embodiment of the apparatus designed for implementing the method of the invention is characterized in that the apparatus comprises a raster surface from which the glue is transferred to the areas on the surface of the object or fibrous reinforcement determined by the raster pattern. Another preferred embodiment of the apparatus designed for implementing the method, of the invention is characterized in that the apparatus is provided with a belt on which the objects can be conveyed to the press and which moves at a speed exceeding the speed of rotation of the pressing rollers. A third preferred embodiment of the apparatus designed for implementing the method of the invention is characterized in that the apparatus comprises a hydraulic press provided with heating means for pressing the objects as part of the preparatory treatment. A further preferred embodiment of the apparatus designed for implementing the method of the invention is characterized in that the glue spreader is provided with a perforated supply tube for supplying the gluing substance from a container, heating channels for heating the glue and at least one distributor tube for spreading the glue. Yet another preferred embodiment of the apparatus designed for implementing the method of the invention is characterized in that the apparatus comprises a die-cutting device for making finger joints or equivalent between the objects. Yet another preferred embodiment of the apparatus designed for implementing the method of the invention is characterized in that the apparatus is provided with a pressing means for pressing the objects against the belt. The invention is described in the following in greater detail by the aid of examples, referring to the drawings attached, wherein: Fig. 1 represents a veneer planing machine. Fig. 2 illustrates the process of drying and pressing the veneer. Fig. 3 shows how the edges of the veneer leaves are evened. Fig. 4 illustrates the process of jointing veneer leaves. Fig. 5- illustrates the process of die-cutting the veneer sheets. Fig. 6 illustrates the process of seaming veneer sheets together to produce a continuous hide. Fig. 7 illustrates the process of producing a glued tissue. Fig. 8 shows an apparatus for jointing veneer leaves in longitudinal section. Fig. 9 shows an apparatus for jointing veneer leaves in longitudinal section. ■ Fig. 10 shows an apparatus for jointing veneer leaves in longitudinal section. Fig. 11 shows an apparatus for jointing veneer leaves in longitudinal section. Fig. 12a shows an apparatus for jointing veneer leaves in longitudinal section. Fig. 12b is a magnified view of a drive roller. Fig. 12c shows an apparatus for jointing veneer leaves in longitudinal section. Fig. 12d shows a raster surface. Fig. 12e shows a scraping device. Fig. 13 shows an apparatus for jointing veneer leaves in lngitudinal section. Fig. 14 is shows an apparatus for seaming veneer leaves to produce a continuous hide, seen in longitudinal section. Fig. 15a represents a glue spreader. Fig. 15b shows the glue spreader in longitudinal section. Fig. 16a represents a second glue spreader. Fig. 16b shows the second glue spreader in longitudinal section. Fig. 17 represents a pressing roller. Before the veneer is coated, the veneer material has. to be • prepared in a Suitable manner. This is done by cutting the logs with a veneer plane and sorting the veneer leaves thus obtained either manually or using e.g. a computer-controlled system to select the leaves with the desired grain patterns. The wood material is planed using e.g. a bevel cutter, producing veneer leaves of a thickness varying from 0.15 mm to a few mm. The thinner the leaf, the better the veneer surface. The width of the veneer leaves obtained depends on the diameter of the logs from which they are planed. The veneer can also be produced by cutting the logs along the annual rings with a veneer-cutting machine. Veneer produced in this manner has a rougher surface than veneer obtained by planing. If necessary, sheets with repeated grain patterns can be produced from one log. Fig. 1 shows a planing machine 1 with which veneer leaves are cut from logs, which move around and through the machine as indicated by the arrows. The grain patterns in the veneer leaves thus obtained correspond to those in solid wood. Thus it is possible to economize on wood material, veneer- finished surfaces being only used where they are visible, e.g. in furniture, wall panels etc. Instead of a planing machine, a veneer-cutting machine may also be used. The preparatory treatment of the veneer leaves includes a drying and pressing operation ensuring that the veneer leaves will not shrink during the other operations they are to undergo and that a good and durable surface finish is achieved without grinding. Fig. 2 shows a drying machine 3 in which the veneer leaves 4 are dried. Drying is necessary because the veneer leaves when cut from logs have a high moisture content (about 60% in sheets of 0.8 mm). The drying machine is a continuously operated roller drier which gives a final humidity of about 8%, which is low enough to ensure a good adhesion of the impregnant and the plastic layer to be applied to the veneer surface. The dried veneer is conveyed by a conveyor 4 to a roller spreader 5, which applies an impregnant to the veneer. The impregnant ensures that e.g. the glue applied in fine dosages to the veneer from a raster surface will not penetrate the veneer when a finishing surface is fixed on it. From the roller spreader 5, the veneer leaves are conveyed to a press 6, in which they are straightened and impregnated. During this preparatory treatment, the veneer leaves, produced by planing or cutting, can be pressed flat under a pressure of 20 - 250 bar in a temperature of 120 - 200 °C,depending on the variety of wood they were produced from. As a result, straight and flat impregnated veneer leaves are obtained. The veneer is impregnated, flattened and, if necessary, shaped by the thermopress described above, by smelting an anti-fire agent, a driable kind of oil, such as linseed oil. or a plastic material so that it is spread on the veneer surface and absorbed in the wood material itself. The applicable pressures vary depending on the variety of wood and thickness of the veneer. By using high pressure values, e.g. 250 - 1500 N/cm , the wood material can be rendered denser and more durable than using low pressures. When thermoplastic materials such as polyethylene or polyester are used, the pressing times vary within the range 5 - 30s. The press consists of an upper and a lower metal box 7 and 8, which are provided with pressing membranes made of silicone rubber or teflon. Using a hydraulic pump, a pressure is created in the container thus formed, by pumping oil into it to press the surfaces to be joined together. The pressure in the container is thus nearly the same as that in the hydraulic pump. The oil can be heated and cooled by means of a heating unit. Next, the stack of veneer leaves is sawn or planed at the ends and edges. The veneer leaves may be provided with bevellings of varying sizes. The larger the bevelling, the stronger the resulting joint. Every second sheet can be rotated around its longitudinal axis to produce a continuous wood surface pattern. The sides of the veneer leaves are evened by cutting them with a veneer saw 9 as shown in fig. 3 to ensure that the joint between the leaves will be as smooth and unnoticeable as possible. Fig. 4 shows an apparatus used for jointing veneer leaves. Using a stacking machine 27 as shown in fig. 5, the veneer leaves are supplied onto a collection table 10, where they are straightened and placed in succession either mechanically or manually so that they can be conveyed to the jointing machine. The .veneer leaves are jointed with the aid of a glued tissue, which makes it possible to achieve a continuous jointing procedure that is considerably faster than the methods currently used. In the apparatus shown in fig. 4, the veneer leaves are next conveyed, as indicated by the arrow, to a press 12 consisting of a pair of rotating rollers. Simultaneously, a fibrous reinforcement 13, 14 and 15 is supplied to the press in three bands from three rolls 16, 17 and 18. The fibrous reinforcement may be e.g. a tissue on which a thermoplastic material has been spread with a raster roller. In the press 12, the reinforcement or plastic material is pressed onto the veneer leaves 11. Thereupon the leaves are conveyed by a conveyor to a heating device 19, where the reinforcement is attached to the veneer. The speed of the conveyor is lower than the speed at which the veneer leaves are conveyed to the press 12, so that the leaves are pushed against each other when entering the press 12. If no glue 1ms been applied to the reinforcement before it enters the pressing device 12, the heater 19 may be replaced with a glue spreader. The glue may be e.g. polyester resin. As indicated by fig. 4, the veneer leaves can be joined together so as to produce either separate veneer sheets or a continuous broad band in which the individual leaves lie either transversely or longitudinally relative to the direction of movement. In the latter case the veneer leaves are placed longitudinally side by side on the conveyors. The final jointing is effected by another press, to which the veneer leaves are conveyed by a conveyor. The upper one of the two rollers of the second press serves simultaneously as one of the drive rollers of a third conveyor. The third conveyor is provided with a broad silicone or teflon belt 21 which conveys the veneer and simultaneously wipes off any extra glue. From the third conveyor, the jointed veneer is reeled up on a roll 22 when a continuous veneer hide is being produced. The figure also shows a finished roll 35 of veneer and a cutting device 24, which is used if the veneer is cut into sheets 25. The " die-cutting machine shown in fig. 5 is used to produce a cut of the required form, e.g. a saw-edge cut, in the sheet edges when sheets are to be seamed together. The veneer sheets 26 are lifted by means of suction pads 27 onto the machine, whereupon they are moved by a conveyor 28 to the cutter 29. After the cut has been made, the sheet is seized by a lifter 30 and moved to a stack. By employing non- symmetrical die-cutting it is possible to hide the seam in the patterns formed by the annual rings in the wood material. On the sheet seaming line in fig. 6 the veneer sheets are joined together transversely to the grain of the wood, so that the joining fingers produced by the die-cutting.machine are interlaced with those on the next sheet and the joint is held together by the plastic coat pressed and heated on the veneer. The result is a finished veneer that is very durable and requires no further finishing, such as varnishing. By varying the thickness of the plastic coat it is possible to produce surfaces corresponding to different varnishing degrees. The veneer sheets 31 are lifted by means of suction pads 32 onto the seaming machine and, as explained in connection with fig. 4, corresponding to the jointing of veneer leaves, conveyed to a press 36, to which also a band of plastic coating is supplied. The plastic coat is obtained by spreading a plastic material on a reinforcing tissue by means of a spreader 34. Next, the plastic coat obtained is preheated with a heating unit 35. In the press 36, the plastic coat is pressed onto the veneer sheets, which are conveyed to the press at a speed higher than the speed of rotation of the pressing rollers, so that the sheets are pushed edgewise against each other. Next, the sheets thus joined together are conveyed to a heater 37 and further to a conveyor and pressing unit 38, from where they are gathered as a finished product 39 onto a roll. A finished roll 40 is shown in fig. 6. The apparatus in fig. 7 serves for producing the glued tissue which is used for jointing the veneer leaves or seaming the veneer sheets together and which gives the resulting veneer hide an elastic property and a finished surface. The glued tissue is made e.g. from a polyester gauze or non-woven polypropylene fibres of 10 - 100 g/mϋ and melt glue, which is spread on the tissue with a glue spreader 42, thus producing a finished surface to be fixed on the veneer. The figure also shows an auxiliary band 43 which can be used as a support in producing the glued tissue and which is reeled back on another roll 44. The figure also shows ro.llers 45 over which the glued tissue produced can be passed to let it cool- down before being reeled up on a roll 46. Fig. 8 presents a sectional view of an apparatus for jointing veneer. In the apparatus shown in fig. 8, the veneer leaves 47 are supplied onto a conveyor, which moves them to the first press. The conveyor consists of rollers 48 - 50 and a broad belt 51 running over the rollers, the belt being made of a thin material to precise dimensions. The veneer leaves are directed towards the belt by means of a guide 52 and pressed against the belt by a pressing means consisting of small rollers 53, hydraulic cylinders 54 and level-surfaced guides placed parallel to the belt, which prevent the leaves from overlapping. Instead of hydraulic cylinders, screws may be used. The rollers 53 and the guide 52 may be mounted in a slightly oblique position, so that when the veneer sheets are placed longitudinally side by side on the belt, they will be pushed sideways together. Simultaneously with the veneer leaves, a fibrous reinforcement 55, which may be a wood fibre based tissue impregnated e.g. with melt glue, is supplied to the press from a roller 56. The reinforcement is pressed onto the veneer leaves by a press consisting of two rollers 57 and 58. Before the reinforcement enters the press, glue is spread on it using e.g. the glue spreading equipment described below. On emerging from the press, the veneer leaves, which are now held closely together, are conveyed by a second conveyor to a heater 59, where the reinforcement is glued fast on the veneer. The second conveyor consists of the lower roller 58 of the press, a silicone or teflon belt 60 and another roller 61. The speed of the second conveyor is lower than that of the first conveyor, which has the effect that the veneer leaves are pushed together before entering the first press. To ensure that the veneer sheets are held firmly in place on the second conveyor, the belt of the conveyor is perforated and suction nozzles 62 are provided below the belt, so that the veneer is held tightly on the belt by the force of the suction. The final jointing is effected in a second press, to which the veneer leaves are conveyed by the second conveyor. The second press consists of the second roller 61 of the second conveyor and an upper roller 63. The jointed veneer is conveyed further by a third conveyor. The upper roller 63 of the second press constitutes one of the drive rollers of the third conveyor. The third conveyor has a broad silicone or teflon band 64 which conveys the veneer and prevents the veneer from getting glued to the belt because the glue when cooled will not stick to the band, and another roller 65. The arrows on the rollers indicate the direction of rotation. Through a nozzle 66, air is blown at the veneer leaves to guide them to the press. Fig. 9 presents a sectional view of an apparatus for jointing veneer. In the apparatus shown in fig. 9, the veneer leaves 47 are supplied onto a conveyor which conveys them to the first press. The conveyor consists of rollers 48 - 50 and a broad belt 51 running over the rollers. The veneer leaves are directed towards the belt by means of a guide 52 and pressed against the belt by a pressing means consisting of small rollers 53, hydraulic cylinders 54 and level-surfaced guides placed parallel to the belt, which prevent the leaves from overlapping. The rollers 53 and the guide of the pressing means may be mounted in a slightly oblique position, so that when the veneer leaves are placed longitudinally side by side on the belt, they will be pushed against each other. Simultaneously with the veneer leaves, a fibrous reinforcement 66 with no glue on it is supplied to the press from a roller 67. The reinforcement is pressed onto the veneer leaves by a press consisting of two rollers 57 and 58. On emerging from the press, the veneer leaves, which are now held closely together, are conveyed by a second conveyor -to a glue spreader 68, which spreads the glue. The' second conveyor consists of the lower roller 58 of the press, a silicone or teflon belt 60 and another roller 61. The speed of the second conveyor is lower than that of the first conveyor, which has the effect that the veneer leaves are pushed together before entering the first press. To ensure that the veneer leaves are held firmly in place on the second conveyor, the belt of the conveyor is perforated and suction nozzles 62 are provided below the belt, so that the veneer is held tightly on the belt by the force of the suction. The final jointing is effected in a second press, to which the veneer leaves are conveyed by the second conveyor. The second press consists of the second roller 61 of the second conveyor and an upper roller 63. The jointed veneer is conveyed further by a third conveyor. The upper roller 63 of the second press constitutes one of the drive rollers of the third conveyor. The third conveyor has a broad silicone or teflon band 64 which conveys the veneer and prevents it from getting glued to the belt because the glue when cooled will not stick to the band, and another roller 65. Through a nozzle 66, air is blown at the veneer leaves to guide them to the press. Fig. 10 presents a sectional view of an apparatus for jointing veneer. In the apparatus shown in fig. 10, the veneer leaves 47 are supplied onto a conveyor which conveys them to the first press. The conveyor consists of rollers 48 - 50 and a broad belt 51 running over the rollers. The veneer leaves are directed towards the belt by means of a guide 52 and pressed against the belt by a pressing means consisting of small rollers 53, hydraulic cylinders 54 and level-surfaced guides placed parallel to the belt, which prevent the leaves from overlapping. The rollers and the guide of the pressing means may be mounted in a slightly oblique position, so that when the veneer leaves are placed longitudinally side by side on the belt, they will be pushed against each other. Simultaneously with the veneer leaves,^a fibrous reinforcement 66 with no glue on it is supplied to the press from a roller 67. The reinforcement is pressed onto the veneer leaves by a press consisting of two rollers 57 and 58. On emerging from the press, the veneer leaves, which are now held closely together, are conveyed by a second conveyor to a funnel-shaped glue spreader 69, from which the glue - e.g. in powdered form - is spread on the veneer leaves and the reinforcement. The funnel may be provided with a scraping device. The second conveyor consists of the lower roller 58 of the press, a silicone or teflon belt 60 and another roller 61. The speed of the second conveyor is lower than that of the first conveyor, which has the effect that the veneer leaves are pushed together before entering the first press. To ensure that the veneer leaves are held firmly in place on the second conveyor, the belt of the conveyor is perforated and suction nozzles 62 are provided below the belt, so that the veneer is held tightly on the belt by the force of the suction. The final jointing is effected in a second press, to which the veneer leaves are conveyed by the second conveyor. The second press consists of the second roller 61 of the second conveyor and an upper roller 63. The jointed veneer is conveyed further by a third conveyor. The upper roller 63 of the second press constitutes one of the drive rollers of the third conveyor. The third conveyor has a broad silicone or teflon band 64 which conveys the veneer and prevents it from getting glued to the belt because the glue when cooled will not stick to the band, and another roller 65. Through a nozzle 66, air is blown at the veneer leaves to guide them to the press. Fig. 11 presents a sectional view of an apparatus for jointing veneer. In the apparatus shown in fig. 11, the veneer leaves 47 are supplied onto a conveyor, which moves them to the first press. The conveyo -consistsgof rollers 48 - SO and a broad belt 51 running over the rollers, ' the belt being made of a thin material to precise dimensions. The veneer leaves are directed towards the belt by means of a guide 52 and pressed against the belt by a pressing means consisting of small rollers 53, hydraulic cylinders 54 and level-surfaced guides placed parallel to the belt, which prevent the leaves from overlapping. Instead of hydraulic cylinders, screws may be used. The rollers of the pressing means and the guide may be mounted in a slightly oblique position, so that when the veneer leaves are placed longitudinally side by side on the belt, they will be pushed against each other. Simultaneously with the veneer leaves,' a coat of thermoplastic material, e.g. polyethylene, is supplied to the press from a roller 71 and applied to the upper surface of the veneer, while a fibrous reinforcement 72, which may be a wood fibre based tissue impregnated with melt glue, is supplied to the press from another roller 73 and applied to the underside of the veneer. The reinforcement is pressed onto the veneer leaves by a press consisting of two rollers 57 and 58. Before the reinforcement enters the press, glue is spread on it using e.g. the glue spreading equipment described below. On emerging from the press, the veneer leaves, which are now held closely together, are conveyed by a second conveyor to a heater 59, where the plastic coat and the reinforcement are glued fast to the veneer. The second conveyor consists of the lower roller 58 of the press, a silicone or teflon belt 60 and another roller 61. The speed of the second conveyor is lower than that of the first conveyor, which has the effect that the veneer leaves are pushed together before entering the first press. To ensure that the veneer sheets are held firmly in place on the second conveyor, the belt of the conveyor is perforated and suction nozzles 62 are provided below the belt, so that the veneer is held tightly on the t lt by the force of the suction. The final jointing is effected in a second press, to which the veneer leaves are conveyed by the second conveyor. The second press consists of the second roller 61 of the second conveyor and an upper roller 63. The jointed veneer is conveyed further by a third conveyor. The upper roller 63 of the second press constitutes one of the drive rollers of the third conveyor. The third conveyor has a broad silicone or teflon band 64 which conveys the veneer and prevents the veneer from getting glued to the belt because the glue when cooled will not stick to the band, and another roller 65. The direction of rotation is indicated by arrows shown on the rollers. Through a nozzle 66, air is blown at the veneer leaves to guide them to the press. Fig. 12a presents a sectional view of an apparatus for jointing veneer. In the apparatus shown in fig. 12a, the veneer leaves 74 are supplied onto a conveyor which conveys them to the first press. The conveyor consists of rollers 75 - 77 and a broad belt 78 running over the rollers. The veneer leaves are directed towards the belt by means of a guide 79 and pressed against the belt by a pressing means consisting of small rollers 80, hydraulic cylinders 81 and level-surfaced guides placed parallel to the belt, which prevent the leaves from overlapping. Instead of hydraulic cylinders, screws may be used. The rollers and the guide of the pressing means may be mounted in a slightly oblique position, so that when the veneer leaves are placed longitudinally side by side on the belt, they will be pushed against each other. Simultaneously with the veneer leaves, a fibrous reinforcement 82 with no glue on it is supplied to the press from a roller 83. The reinforcement is pressed onto the veneer leaves by a press consisting of two rollers 84 and 85. At the same time, glue is supplied from a glue spreader 88 onto a raster belt 87 running around rollers 84 and 86, the glue being transferred from the raster belt to the surfaces pressed together. The glue spreader can be placed e.g. as shown in the figure, just above the roller 84. The glue spreader is provided with an oscillated scraping device 89 and a counterpart 90, whose position is controlled by means of a hydraulic hose 91 by adjusting the pressure in the hose. In this manner, the distance between the counterpart and the support 92 can be varied and the glue spreader thus rotated on its shaft so as to turn it to the correct position. On emerging from the first press, the veneer leaves, which are now held closely together, are conveyed by a second conveyor to a second press consisting of two rollers 86 and 93. The second conveyor consists of the lower roller 85 of the first press, a silicone or teflon band 93 and the lower roller 94 of a second press. The speed of the second conveyor is lower than that of the first conveyor, which has the effect that the veneer leaves are pushed together before entering the first press. To ensure that the veneer leaves are held firmly in place on the second conveyor, the belt of the conveyor is perforated and suction nozzles 95 are provided below the belt, the veneer being held tightly on the belt by the force of the suction. The final jointing is effected in the second press. The raster band 87 is provided with a raster pattern, from which the glue is transferred to the appropriate areas on the veneer leaves or non-woven fibrous material of e.g. 10 - 100 g/m . Fig. 12b is a magnified view of detail A in fig. 12a, showing the roller 77 and the belt. The veneer leaves are guided towards the press by blowing pressurized air at them through a nozzle 96, so that they will move in the correct • direction. Fig. 12c presents a sectional view of an apparatus for jointing veneer. In the apparatus shown in fig. 12c, the veneer leaves 74 are supplied onto a conveyor which conveys them to the first press. The conveyor consists of rollers 75 - 77 and a broad belt 78 running over the rollers. The veneer leaves are directed towards the belt by means of a guide 79 and pressed against the belt by a pressing means consisting of small rollers 80, hydraulic cylinders 81 and level-surfaced guides placed parallel to the belt, which prevent the leaves from overlapping. Instead of hydraulic cylinders, screws may be used. The rollers and the guide of the pressing means may be mounted in a slightly oblique position, so that when the veneer leaves are placed longitudinally side by side on the belt, they will be pushed against each other. Simultaneously with the veneer leaves, a fibrous reinforcement 82 with no glue on it is supplied to the press from a roller 83. The reinforcement is pressed onto the veneer leaves by a press consisting of two rollers 97 and 85. Roller 97 is provided with a raster surface e.g. as shown in fig. 12d, so that glue is applied to the areas on the veneer or reinforcement corresponding to the raster pattern. The glue spreader is provided with a scraping device 89 and a counterpart 90, whose position is controlled by means of a hydraulic hose 91 by adjusting the pressure in the hose. In this manner, the distance between the counterpart and the support 92 can be varied and the glue spreader thus rotated on its shaft so as to turn it to the correct position. On emerging from the first press, the veneer leaves, which are now held closely together, are conveyed by a second conveyor to a second press consisting of two rollers 86 and 93. The second conveyor consists of the lower roller 85 of the first press, a silicone or teflon band 93 and another roller 94. The speed of the second conveyor is lower than that of the first conveyor, which has the effect that the veneer leaves are pushed together before entering the first press. To ensure that the veneer leaves are held firmly in place on he second conveyor, the belt of the conveyor i.s perforated and suction nozzles 95 are provided below the belt, the veneer being held tightly on the belt by the force of the suction. Roller 97 is provided with a raster surface like that shown in fig. 12d, which is produced by etching, arc machining or casting. The raster surface consists of grooves 99 and elevations 98. The glue is wiped off from the elevated surfaces 98 by the scraping device, so that glue is only applied to the veneer leaves from the grooves 99. Fig. 12e shows the scraping device, which consists of a frame 100 and a scraping head 101, whose movements are controlled by hydraulic means using a hose 102, the scraping head movements being oscillatory. Fig. 13 presents a sectional view of an " apparatus for jointing veneer. In the apparatus shown in fig. 13, the veneer leaves 47 are supplied onto a conveyor which conveys them to the first press. The conveyor consists of rollers 48 - 50 and a broad belt 51 running over the rollers. The veneer' leaves are passed to a glue spreader 68, which spreads glue on them. The veneer leaves are directed towards the belt by means of a guide 52 and pressed against the belt by a pressing means consisting of small rollers 53, hydraulic cylinders 54 and level-surfaced guides placed parallel to the belt, which prevent the leaves from overlapping. The rollers 53 and the guide of the pressing means may be mounted in a slightly oblique position, so that when the veneer leaves are placed longitudinally side by side on the belt, they will be pushed against each other. Simultaneously with the veneer leaves, a fibrous reinforcement 66 with no glue on it is supplied to the press from a roller 67. The reinforcement is pressed onto the veneer leaves by a press consisting of two rollers 57 and 58. The second conveyor consists of the lower roller 58 of the press, a silicone or teflon band 60 and another, roller 61. The speed of the second conve'yor is lower than that of the first conveyor, which has the effect that the veneer leaves are pushed together before entering the first press. To ensure that the veneer leaves are held firmly in place on the second conveyor, the belt of the conveyor is perforated and suction nozzles 62 are provided below the belt, so that the veneer is held tightly on the belt by the force of the suction. The final jointing is effected in a second press, to which the veneer leaves are conveyed by the second conveyor. The second press consists of the second roller 61 of the second conveyor and an upper roller 63. The -jointed veneer is conveyed further by a third conveyor. The upper roller 63 of the second press constitutes one of the drive rollers of the third conveyor. The third conveyor has a broad silicone or teflon band 64 which conveys the veneer and prevents it from getting glued to the band because the glue when cooled will not stick to the band, and another roller 65. Through a nozzle 66, air is blown at the veneer leaves to guide them to the press. In a manner corresponding to the jointing of veneer leaves, veneer sheets can also be seamed together to produce larger sheets. In this case, in addition to the steps mentioned at the beginning of the description, the preparatory operations include the jointing of veneer leaves into smaller sheets as well as the making of finger joints as shown in fig. 6. A coat of a plastic material, e.g. polyethylene or polyester, may be smelted on the upper surface by means of a heater, and a fibrous reinforcement may be attached to the lower surface. The thermoplastic coat is smelted and pressed onto the veneer over the whole length and breadth of the hide, whereupon it is quickly cooled. In this way, elastic and pliable " veneer hides with tight joints and a finished surface are produced. Fig. 14 shows an apparatus for seaming and coating veneer sheets as exemplified by fig. 6. In the apparatus in fig. 14, the veneer sheets 103 are supplied onto a conveyor which conveys them to the first press. The conveyor consists of rollers 104 - 106 and a broad belt 107 running over the rollers. The veneer leaves are directed towards the belt by means of a guide 108 and pressed against the belt by a pressing means consisting of small rollers 109, hydraulic cylinders 110 and level-surfaced guides placed parallel to the belt, which prevent the leaves from overlapping. Simultaneously with the sheets, a plastic coating band 113, running over the roller 114, is supplied to the press, said plastic coat being obtained from a supply roll 119 and passed over a tightening roller 118 to a glue spreader consisting of a spreading tube 116 and a roller 117, and further through a preheating unit 115 to the roller 114 mentioned above. The plastic coat is pressed onto the sheets by a press consisting of a pair of rollers 111 and 112, the upper one 111 of which is hard chrome plated and provided with heating means, while the lower one 112 is as shown in fig. 17. The second conveyor, which consists of the lower roller 112 of the press, a silicone or teflon band 120 and another roller 121, conveys the sheets to the second press. The speed of the second conveyor is lower than that of the first conveyor, so that the veneer sheets are pushed together when entering the first press. To ensure that the veneer sheets are held firmly in place on the second conveyor, the belt of the conveyor is perforated and the apparatus is provided suction nozzles 124, so that the veneer is held tightly on the belt by the force of the suction. The final jointing is effected in a second press, which consists of the second roller 121 of the second conveyor and an upper roller 122a. The seamed ' veneer is conveyed further by a third conveyor. The upper roller 122 of the second press constitutes one of the drive rollers of the third conveyor. The third conveyor has a broad silicone or teflon band 123 which conveys the veneer and prevents the veneer from getting glued to the belt because the glue when cooled will not stick to the band, and another roller 122b. The glue is applied using the spreading devices presented in figures 15a, 15b, 16a and 16b. Fig. 15a also shows how the glue is supplied to the glue spreader 125. Fig. 16b shows the glue spreader as as sectioned along the line A-A. Using a pump 128, the glue is supplied from a glue container 126, which is provided with heating means and a cylinder 127, through a hose 129, also provided with heating means, to the glue spreader 125. In the spreading device 125, the glue is first fed via a proportionally perforated supply tube 130 into an expansion cavity formed inside two distribution tubes 131 and 132, which are mounted one inside the other, said cavity being provided with heating channels 133 to keep the glue warm. The distribution tubes are provided with apertures 135a and 135b, whose position relative to each other determines the volume of glue flowing out of the spreading device, as the relative position of the tubes can be changed by rotating the inner tube 132 by means of a rotating mechanism, which is not shown in the figure. The outer tube has to be provided with isthmuses 134 to render the tube sufficiently rigid in the region of the apertures. Figs 16a and 16b show another device for spreading the glue. The device is provided with a perforated supply tube 136 through which the glue is supplied from the container, not shown in the figure. Through the holes in the supply tube, the glue flows intb the space inside the distribution tube 137, from.where it spreads ' through the aperture 1-44 onto_ the surface to be glued. The glue is heated by means of heating channels 142 mounted inside the distribution tube, and the volume of glue flow out of the tube is determined by the position of the aperture 144 in the distribution tube relative to the aperture in the distributor section 138. The device may have two distribution tubes mounted one inside the other. The distributor piece 138 is attached to the distribution tube 137 by means of securing screws 143, with which the distributor piece is fixed in the desired position to provide a suitable size of aperture. The device is also provided with securing flanges 139 and 141 and a tightening flange 140 with which the device is secured and tightened. Fig. 17 is a sectional view of the upper pressing roller of a press, e.g. roller 57 in fig. 8. The roller is provided with means for heating and cooling. Inside the roller there are silicone rubber hoses 147 which act as hydraulic bags, supplied with oil via a channel inside the shaft 149 of the roller. By means of the bags, it is possible to control the pressure which is applied to the veneer and the coating from the roller surface, mounted on- top of the frame 146. The oil is supplied to the bags from a hydraulic unit not shown in the figure. Also, an even line pressure over the whole width of the roller is achieved. It is obvious to a person skilled in the art that the embodiments of the invention are not restricted to the examples discussed above, but that they may instead be varied in the scope of the following claims. For example, instead of veneer, wooden objects of a thickness in the range 0.i5 - 5 cm may be used.

Claims: CLAIMS 1. Method for jointing or seaming and laminating level- ' surfaced objects, such as veneer leaves or sheets or other wooden objects, characterized in that, for jointing or seaming the objects together, the objects (10;31;47;74;103) are passed through a press consisting of two pressing rollers (12;57;58;84;85;97;111,112) in such manner that when they come to the press, the objects are pushed edgewise together and a fibrous reinforcement (13-15;55;66;72;82) or a coat of plastic (33;70;113) is pressed at least to one side of the objects, said reinforcement or plastic coat being attached to the objects by gluing or smelting. 2. Method according to claim 1, characterized in that the glue is applied onto the objects by first spreading it on a raster surface, (87;97) from which it is then transferred to the areas on the surface of the object or-fibrous reinforcement determine.d by the roaster pattern. - 3. Method according to claim 1 or 2, characterized in that the objects are conveyed to the press on a belt (51;78;107) which moves at a speed exceeding the speed of rotation of the pressing rollers. 4. Method according to any one of the claims 1 - 3, characterized in that the preparatory treatment of the objects includes pressing the objects by means of a hydraulic press (6) provided with heating means. 5. Apparatus designed for implementing the method of claim 1, characterized in that the apparatus comprises at least one conveyor for moving the objects (10;31;47;74;103), at least one press consisting of two pressing rollers (12;57;58;84;85;97;111,112) for pressing a fibrous reinforcement (13-15;55;66;72;82) or a plastic coat (33;70;113) at least on one side of the object, and a glue spreading device (68;69;88;34;35;38) for spreading the glue or a heating device (19;37;59;115) for heating the glue or the plastic. 6. Apparatus according to claim 5, characterized in that the apparatus comprises a raster surface (87;98) from which the "glue is transferred to the areas on the surface of the object or fibrous reinforcement determined by the raster pattern. 7. Apparatus according to claim 5 or 6, characterized in that the apparatus is provided with a belt (51;78;107) on which the objects can be conveyed to the press and which moves at a speed exceeding the speed of rotation of the pressing rollers. > 8. Apparatus according to any one of the claims 5 - 7, characterized in that the apparatus comprises a hydraulic press (6) provided with heating means for pressing the objects as part of the preparatory treatment. 9. Apparatus according to any one of the claims 5 - 8, characterized in that the glue spreader is provided with a perforated supply tube (130;136) for supplying the gluing substance from a glue container (126), heating channels (133;142) for heating the glue and at least one distributing tube (131;132;137) for spreading the glue. 10. Apparatus according to any one of the claims 5 - 9, characterized in that the apparatus comprises a die cutting device for making finger joints or equivalent between the objects (26). 11. Apparatus according to any one of the claims 5 - 10, characterized in that the apparatus is provided with a pressing means for pressing the objects against the belt.

Inventors: RINNE ERKKI, RINNE, ERKKI
Applicants: RINNE ERKKI, RINNE, ERKKI
Application year: 1987
Main classification: B27D1
IPC codes: B27D1, B27G11, B29C31, B29C41, B29C43, B29C63