FI72910C - FOERFARANDE OCH ANORDNING FOER BOEJLIGGOERNING AV FANER. - Google Patents

Description

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SUOMI FINLAND

(Fl) (21) Patent application - Patentansökning 782246 (22) Application date - Ansökningsdag 14.07.78

National Board of Patents and Registration (23) Start date - Giitighetsdag 14.07.78

Patent-och reflisterstyrelsen (41) Became public-Biivit offentiig 15.01.80 (44) Date of dispatch and publication: 30.04.87

Ansökan utlagd och utl.skriften publicerad (86) Kv. Application-Int. ansökan (32) (33) (31) Privilege claimed - Begärd priority (71) Meinan Machinery Works, Inc., no. 1-38, Kaj1 ta, Yokone-cho, Ohbu-shi, Aichi-ken, Japan-Japan (JP) (72) Katsuji Hasegawa, Aichi-ken, Japan-Japan (jP) (74) Leitzinger Oy (54) Method and device for making veneer flexible - Förfarande och anordning för böj1iggörning av faner

The invention relates to a method for making a veneer flexible, wherein the veneer cut in a previous step is moved substantially perpendicular to the direction of the grain of the wood, and the blade members form a plurality of substantially causal incisions on the other surface of the veneer during transfer.

The invention further relates to an apparatus for carrying out the method, in which the lower roll rotated by the drive is adapted to move the veneer substantially perpendicular to the direction of the veneer causes, and the cutting device is positioned opposite the lower roll at a predetermined distance from the lower roll.

When veneer is turned from wood, i.e. logs, cracks usually form on the wrong surface of the veneer, i.e. on its machined or separated surface, whereby the length of the veneer increases greater on the wrong 2 72910 surface than on its opposite surface, resulting in so-called curling.

A common way to prevent this curling is to form a number of incisions on the surface side of the veneer, corresponding to cracks, to compensate for the length difference between the two surfaces. However, this operation is not effective because the mechanically formed incisions refill quickly after the cutting blade is retracted, due to the elasticity of the veneer. The refilled incisions remain on the surface of the veneer only as straight lines of the cutting blade.

Therefore, the main object of the present invention is to increase the flexibility of the veneer in order to obtain a good yield of products and to rationalize the later stages of manufacture, which increases the efficiency of plywood manufacture.

According to the invention, the above-mentioned object is achieved in that the veneer is bent by changing its direction of travel away from the cut surface so that a large number of cracks develop from said cuts.

The device according to the invention is characterized in that the guide member is adapted to guide the veneer during transfer and that a counter member is arranged opposite the guide member, which is adapted to contact the veneer during transfer to bend the veneer in a direction away from the cutting surface.

The above and other objects and advantages of the invention will become more apparent from the description of the preferred embodiments with reference to the accompanying drawings, in which:

Figure 1 is a side view of an essential part of an embodiment of the invention, illustrating the manner in which veneer is made using the method of the invention.

Figures 2 and 3 show two embodiments of a cutting roller used in the embodiment shown in Figure 1.

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Fig. 4 shows a front view of a cutting roll and an anvil roll cooperating therewith, as well as drive devices, adapted to the embodiment shown in Fig. 1.

Figure 5 schematically shows a veneer with incised grooves made with a device according to the invention.

Fig. 6 schematically shows cracks formed from incisions in the veneer of Fig. 5 by bending the veneer with a device according to the invention.

Figure 7 is a side view of an embodiment of the invention.

Figure 8 shows a side view of another embodiment of the invention.

Preferred embodiments of the invention are explained below with reference to the accompanying drawings.

As shown in Figures 1-3, the device according to the invention has an incision forming roller A supporting a plurality of incision forming cutting members 3 on its circumferential surface, an incision forming roller A: opposite the lower roller B, a drive for driving the rollers A and B, a guide member 6 for guiding the veneer C incisions C1 have been made in the cutting members 3, a counter member 7 for bending the veneer C and a conveyor 8 as a transfer device.

The roll A is provided with a plurality of radially projecting, cutting-forming cutting members 3 with a circumferential surface, which are at a desired distance from each other. These cutting members are arranged in several groups, each of which comprises a plurality of cutting members, the groups having a regular or irregular division in the axial direction. At the same time, the roll A has a plurality of recesses 4 which are loosely adapted to receive the respective parts of the counter member 7. Roll A has a raised and recessed circumferential surface. The recessed portions form grooves 4, while the cutting members 3 are formed on the raised portions of the roll A.

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The lower roll B, which is opposite, at a suitable distance from the incision forming roll A, has a plurality of grooves 1 adapted to loosely receive the respective parts of the guide member 6. Roller B is made of iron, hard rubber or resin.

The distance between the two rolls A and B, which allows the cutting member 3 to contact the surface of the roll B, is optimal, although the depth of the incisions to be formed is determined depending on the condition of the veneer C. Thus, the spacing of the rolls is determined so that incisions of suitable depth are formed as the veneer passes through the area between the rollers. This distance between the rollers can be varied and adjusted by the adjusting device 5, which will be explained below.

The drive device for each roll can be an electric motor 9 or alternatively both rollers are driven by means of gears Ib, 3b mounted on the shafts 1a, 3a of the respective rollers. Reference numerals le and 3c denote bearings.

The guide member 6 is adapted to control the veneer roll C. A trailing along the circumferential surface area: the successive path of the cutting means so that the veneer C passes from the rolls A and B through the gap and not pierced by the cutting means 3 can fall out of the cutting member.

The guide member 6 is partially arranged in the grooves 1 of the roll B and has a guide surface 6b comprising a curved part extending between the part in the vicinity of the groove 1 and the counter member 7, following the curvature of the cutting members 3 and a substantially straight part extending away from the roll A.

The counter member 7 is adapted to bend the veneer C at a predetermined angle at the point where the veneer C leaves the cutting members 3, in a direction opposite to the surface on which the incisions Cj are formed. The counter member 7 is partially fitted in the grooves 4 of the roll A and provided with a counter surface 7a located on the side of the guide member 6 and spaced at such a distance from the highest surface 6a of the guide member that the veneer C oi passes through this gap.

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The guide member 6 and the counter member 7 are rigid members attached to the body of the device (not shown).

The incision forming roll A may be formed by a single rigid roll or alternatively by several axially small, axially aligned rollers supported on respective bearings, as shown in Fig. 3. In the latter case, the assembly must be constructed so as to minimize the deflection of the incision forming roll A. The lower roll B is used as a drive roll, and the incision roll A is in this case an idle roll.

In the illustrated embodiment, the bending of the veneer C is achieved near the point where the veneer C is pierced and incised. Punching and bending take place at essentially the same point.

; However, slitting and bending can be performed at spaced points. Thus, for example, although not shown in the drawings, the press roll and the opposite transfer roll are located at a sufficient distance from the points where the incision is made. The press roll is made of a material with a high coefficient of friction, for example rubber. A counter member similar to the illustrated embodiment is positioned in connection with the press roll, while a guide member similar to the illustrated embodiment is located on the discharge side of the press and transfer roll. Thus, the counter member and the guide member cooperate with each other to bend the veneer C in the same manner as in the illustrated embodiment. However, this arrangement is not practical because the cost increases due to the fact that the incision forming member and the bending member are mounted separately from each other.

Referring again to Figure 1, feed conveyors 2 and 2a are provided for feeding veneer C between the incision forming roll A and the anvil roll B. The upper conveyor 2a is unnecessary if the veneer C is fitted between the rollers by hand, but it is necessary when the device according to the invention is used in connection with another manufacturing device, such as a veneer lathe. The discharge conveyor 8 is located on the discharge side of the incision forming roller A.

6 72910 The adjusting device 5 is adapted to allow the distance between the rollers A and B to be adjusted mainly according to the thickness of the veneer and to give the force forcing the cutting members into the veneer C. This adjusting device, if fitted, may consist of a single screw or a combination of a screw and a pneumatic or hydraulic cylinder or spring shown) adapted to provide adjustment. Both rollers can be moved toward and away from each other to adjust the spacing between the rollers.

During operation, when the veneer C is fed between the incision forming roll A and the lower roll B so that the direction in which the veneer C is moved forms a substantially right angle with the direction of the veneer causes, the veneer C is pierced by the cutting members 3 as it passes between the rollers. Thus, when the veneer C is continuously fed, a plurality of incisions Cj_ are formed on its surface, located on the side of the incision forming roll A, as shown in Fig. 5. The veneer C is conveyed along the guide surface 6b of the guide member 6 while still perforated by the cutting members 3. B. Since the veneer C is forcibly fed through the cutting members 3, no blockage can occur. The part of the veneer C which has reached the highest point 6b of the guide member 6 is then pressed by means of the counter surface 7a of the counter member 7, whereby the direction of movement changes. Namely, the counter member 7 forcibly separates the veneer from the cutting members 3 and bends it in the opposite direction to the incision surface, so that the surface of the veneer with the incisions C 1 - becomes convex, while the other surface becomes concave. As a result of this bending, numerous cracks are formed in the incisions of the veneer C, as can be seen in Figure 6.

A typical, preferred embodiment of the invention has been described with reference to Figures 1-4. However, this embodiment is not the only possible one, but the invention can be implemented in many different ways.

Fig. 7 shows an embodiment of the invention in which a slit forming roller A with cutting members on its circumference has been replaced by a plurality of chains A2, each supporting a plurality of cutting members 3. These 7 72910 chains run around respective sprockets Aj supported on a common motor (not shown). using the shaft.

Fig. 8 shows another embodiment in which a plurality of cutting members 3 are mounted to reciprocate towards and away from the path of the veneer via the crank device 15. These cutting members 3 are periodically pressed against the veneer by means of a crank device 15, in order to form a plurality of incisions Ci in the surface of the veneer.

: On the discharge side of the lower roll B, a compression conveyor 17 is arranged, which is adapted to press the veneer C against the support 16 to bend the veneer C. This embodiment works in the same way as: the described embodiments.

As stated, according to the invention, a veneer having a plurality of incisions is bent in the opposite direction to the incision surface, whereby the incisions on this surface form a plurality of cracks. These cracks are not continuous but separate. Most of these cracks are in different directions and extend considerably deep into the veneer, providing a considerable flexible effect.

The critical feature is not the incision of the veneer, but its bending after the incisions formed in the surface of the veneer. Provided that the veneer is bent forcibly without a cutting step, the cracks ‘will run in a straight line in the direction of the causes, resulting in complete cracking or tearing of the veneer. On the other hand, according to the invention, the cracks extend in all directions so that no linear continuity of the notches is formed in the direction of the causes, which guarantees a good flexible effect.

In addition, clogging of the rollers, which tends to occur when the veneer is bent at a very large angle, for example to form an inverted V-shape, is prevented because the veneer is forced forward by the cutting members towards the bending part, which ensures flexible continuous operation of the device.

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Furthermore, since the bending effect is not obtained with an elastic material but with a rigid material, the cracks are precisely defined and evenly distributed.

In addition, since the corrugations caused by the veneer separating from the owl are straightened to smooth the veneer, the feeding or passing of the veneer to the next manufacturing device, such as a cutting device, is greatly improved. At the same time, the joining of the veneers in the next joining step can be carried out without undesirable tearing of the joining strips or the like, since the veneer is planar.

The drying efficiency has also increased much, as the heat transfer to the veneer and the evaporation of water have become more efficient due to the cracking.

On the other hand, the treatment carried out by the method according to the invention provides an effective removal of the internal stress of the veneer. This avoids deformation or distortion of the plywood as well as other problems due to internal stress.

At the same time, the veneer can be handled well, because the veneer produced by the method according to the invention is so flexible that there are no stress concentrations. Furthermore, mixing or entanglement of the veneer fibers is avoided because it has a large number of notches. In addition, it becomes possible to stretch the veneer in a direction perpendicular to the direction of the causes, thus improving the yield.

From the above description, it will be seen that the above-mentioned disadvantages of the prior art have been avoided by the method and apparatus of the present invention. In addition, according to the invention, there is provided a device having a simple structure and an advantageous fit, which considerably increases the flexible effect. The invention provides for the mass production of plywood at low cost and contributes greatly to improved and efficient production in the plywood industry as well as to more efficient use of wood resources.

Claims (11)

A method of making a veneer flexible, wherein the veneer (C) cut in a previous step is moved substantially perpendicular to the direction of the wood grain, and the blade members form a plurality of substantially causal incisions (C 2) on the other surface of the veneer during transfer, characterized in that the veneer is bent by its direction of travel away from the incision surface so that a large number of cracks (C2) develop from said incisions (Cj) · A method according to claim 1, characterized in that the incisions (C 1) are formed by contacting a plurality of blade members (3) rotating about an axis substantially transverse to the path of the veneer with the surface of the veneer (C). Method according to claim 1, characterized in that the blade members (3) are arranged to move back and forth towards and away from the veneer. A method according to claim 1, characterized in that the bending of the veneer (C) is achieved by guiding the veneer in a predetermined direction and then changing its direction of movement at a preselected angle. Apparatus for carrying out the method according to claim 1, wherein in the apparatus the lower roll (B) rotated by the drive is adapted to move the veneer (C) substantially perpendicular to the direction of the veneer causes, and the cutting device (A, 3) is located opposite the lower roll at a predetermined distance from the lower roll, the cutting means (3) of the cutting device are adapted to form a plurality of incisions (C 1) on the second surface of the veneer, extending mainly in the direction of the causes, characterized in that the guide member (6) is adapted to guide the veneer during transfer and a counter member (7) is arranged opposite the guide member is adapted to contact the veneer during transfer to bend the veneer in a direction away from the incision surface. 10 7291 0 Device according to Claim 5, characterized in that the cutting device (A, 3) comprises at least one incision forming roller (A) rotating about an axis substantially transverse to the path of the veneer, consisting of a plurality of discs projecting a plurality of circumferentially radially circumferentially spaced circumferences. spaced apart cutting members (3), the discs being spaced apart (4) in the axial direction of the incision forming roll. Device according to Claim 6, characterized in that the incision-forming rollers (A) are supported by a common shaft. Device according to Claim 6 or 7, characterized in that the incision forming roller (A) is rotated by a drive device. Device according to Claim 5, characterized in that the cutting device (A, 3) comprises a plurality of sprockets (A2) rotated by a drive device and supported by a common axis substantially transverse to the path of the veneer, the chain (A2) passing over each sprocket (A2). and has a plurality of cutting members (3) attached to the outer side of each chain (A2) at predetermined intervals. 9,72910 Device according to claim 5, characterized in that the cutting device (A, 3) comprises a plurality of cutting members (3) arranged in at least one row running substantially transversely to the path of the veneer (C) and that the cutting members are arranged to reciprocate towards the veneer and away from the action of the common crank member (15). 11 7291 0 Patentkray