The present invention relates to a rotary veneer lathe for cutting a wood block to peel therefrom veneer for use in manufacturing glued laminated wood such as plywood, laminated veneer lumber (LVL), etc. The invention relates also to a method of cutting a wood block by such veneer lathe.
A conventional rotary veneer lathe, part of which is shown in
The veneer lathe further has a number of pressure members 109 which is mounted in the knife carriage, each disposed between any two adjacent peripheral drive wheels 105. The pressure member 109 has at the distal end thereof a replaceable insert 9a for pressing against the peripheral surface of wood block 115 immediately upstream of the cutting edge of the knife 101 as seen in the direction in which the wood block 115 is rotated as indicated by arrow. A guide member 1111 is also mounted in the knife carriage between any two adjacent drive wheels 105 for guiding peeled veneer V along the periphery of the spiked drive wheels 105. Immediately downstream of the guide member 111 is disposed a separating member 113 having a contact surface 113a extending so as to intersect an imaginary circle which passes the tip ends of the respective projections 103 of the peripheral drive wheel 105 for separating or disengaging veneer V from the projections 103 of the drive wheels 105.
Referring to
In operation of the veneer lathe, with the wood block 115 supported at the opposite axial ends thereof by spindles (not shown) being driven to rotate in arrow direction by the spindles or the spiked peripheral drive wheels 105, the knife carriage is moved to feed the knife 101 into the wood block 115 at a controlled feedrate thereby to peel by the veneer knife 101 a veneer strip or sheet V with a predetermined thickness from the rotating wood block 115.
It is well known to those skilled in the art that a veneer lathe having the peripheral drive system 108 as shown in
In cutting a wood block for producing veneer with a thickness of, e.g., about 3 mm, the peripheral drive wheels 105 in rotation is engaged at the tooth-like projections 103 thereof with the peripheral surface of the wood block 115, as shown in
It is noted that, when the peripheral drive wheels 105 rotate in arrow direction, the wood block 115 is not rotated instantly with the rotation of the drive wheels 105 because of the cutting resistance exerted by the veneer knife 101 cut into the wood block 115. The force of the peripheral drive wheels 105 acting at the projections 103 thereof on the wood block 115 for rotation is increased while elastically deforming the wood of the block 115 at the projections 103 of the drive wheels 105, and the wood block 115 begins to be rotated for veneer peeling when the above force is increased to exceed the cutting resistance. Thus, the periphery of the wood block 115 is moved slower than the projections 103 of the peripheral drive wheels 105 for the above elastic deformation of the wood block 115. Consequently, the peripheral speed of the spiked drive wheels 105 at the projections 103 thereof is higher than the traveling speed of veneer V peeled from wood block 115 at the location adjacent to the guide members 111, so that the veneer V is subjected to tensile force by the projections 103 and, therefore, the veneer V just peeled from the wood block 115 is formed with a number of splits extending in the direction of wood grain of the veneer V, or in the direction that is perpendicular to the direction in which the veneer V is moved along the periphery of the spiked drive wheels 105. The veneer sheet V moving past the guide members 111 is then brought into contact with the surfaces 113a of the separating members 113 and bent downward as shown in
During initial period of veneer peeling operation before the wood block becomes substantially cylindrical, veneer strips of various narrow widths are produced which are curled or coiled into spiral shape. Such curled veneer strips are troublesome to handle in the subsequent processes, but formation of splits along the wood grain of such veneer strips is effective to minimize curling of veneer strips.
Once the wood block 115 has been rounded up or become substantially cylindrical, a continuous veneer sheet V is peeled from the block 115. When a veneer sheet with a continuous width and free from pierced markings made by the projections 103 of the peripheral drive wheels 105 is needed for use as face veneer of plywood, the peripheral drive wheels 105 are moved for retraction by any suitable actuator as indicated by oblique arrow in
In veneer peeling with the peripheral drive wheels 105 positioned as shown in
If veneer peeling is done with the peripheral drive wheels 105 retracted as shown in
When a knotty coniferous wood block is cut for veneer production, the resulting veneer has in it many knots. If a knot in the veneer may move between any two adjacent guide members 111, the knot is pressed from above by the projections 103 of a peripheral drive wheel 105 and broken to be removed from the veneer, with the result that a veneer sheet is produced which has a defective void portion and, therefore, is unusable as face veneer of plywood or similar panel product.
Therefore, it is an object of the present invention to provide a veneer lathe and a method of cutting wood block by such veneer lathe which can solve the aforementioned problems.
A method of cutting a wood block for production of veneer according to the invention is performed by a rotary veneer lathe having a knife carriage which is equipped with a peripheral drive system for rotating a wood block from its periphery. The knife carriage includes a veneer peeling knife having a cutting edge, and the peripheral drive system has a number of rotatable peripheral drive wheels which are disposed at a spaced interval in parallel relation to the cutting edge of the veneer knife and each of which has on the circumferential periphery a number of tooth-like projections pierceable into peripheral surface of the wood block adjacent to the cutting edge of the veneer knife for driving the wood block from the periphery thereof for rotation about its axis. Though the peripheral drive wheels are mounted in the knife carriage, the wheels are movable relative to the knife carriage. The veneer lathe has a support such as spindles for rotatably supporting the wood block, and the knife carriage further includes a first drive for rotating the peripheral drive wheels, a second drive for moving the peripheral drive wheels relative to the knife carriage, a pressure member disposed adjacent to the peripheral drive wheel for pressing against the peripheral surface of the wood block, a guide member disposed adjacent to the peripheral drive wheel for guiding veneer peeled from the wood block along the peripheral drive wheels, and a separating member disposed downstream of the guide member with respect to the direction of rotation of the peripheral drive wheels for separating the veneer from the peripheral drive wheels. According to a preferred embodiment of the invention, the knife carriage is movable toward the wood block such that the veneer knife on the knife carriage cuts into the peripheral surface of rotating wood block for peeling veneer therefrom.
In a preferred embodiment of the wood block cutting method according to the invention, cutting of the wood block is done with the peripheral drive wheels placed at a first position thereof where the projections of the peripheral drive wheels pierce the peripheral surface of the wood block adjacent to the cutting edge of the veneer knife and the veneer just peeled from the wood block and then moving past the guide member is pierced by the projections to such an extent that substantial splits are formed in the veneer along the wood grain thereof by a force of the projections acting on the veneer, and cutting of the wood block is done also with the peripheral drive wheels placed at a second position thereof where the peripheral surface of the wood block is pierced in the same manner as in the first position, but the projections of the peripheral drive wheels provide no such force to the veneer peeled from the wood block and moving past the guide member that causes the substantial splits in the veneer. In the preferred embodiment, the peripheral drive wheels are movable toward the rotating block from the second position.
In the preferred embodiment, cutting of wood block at the first position of the peripheral drive wheels is done while veneer strips with irregular or varying widths are being peeled from the block and the peripheral drive wheels are moved to their second position after a continuous sheet of veneer begins to be cut from the block. The peripheral drive wheels begins to move at a controlled rate toward the rotating block from the second position when the wood block diameter is reduced to a predetermined value.
In another preferred embodiment, after the peripheral drive wheels are moved from the first position to the second position, they are moved back to the first position when the wood block diameter is reduced to a predetermined value. In still another embodiment, the peripheral drive wheels after moving back to the first position are moved therefrom toward the rotating block.
The present invention also provides a rotary veneer lathe for practicing the method of cutting wood block for production of veneer.
Thus, the peripheral drive wheels are movable relative to the knife carriage in various ways depending on the conditions of wood blocks to be peeled and other requirements, as will be explained more in detail in the description of the preferred embodiments of the invention, which description is made with reference to the accompanying drawings, wherein:
The following will describe a first preferred embodiment of the present invention with reference to
Referring firstly to
Referring to
The first shaft 9 has at one end thereof a reduced or small-diameter portion 9a which is formed integral and coaxial with the first shaft 9. A second shaft 17 in the form of a tube is keyed at 18 on the small-diameter portion 9a of the first shaft 9 for rotation therewith. Specifically, the outer diameter of the second shaft 17 is smaller than that of the first shaft 9 by about 3 mm and the second shaft 17 is fixed in an eccentric relation to the first shat 9 with the axis of the second shaft 17 displaced from the axis of rotation of the first shaft 9 by about 3 mm, as shown in
Referring to
In the above-described arrangement, as the first shaft 9 is rotated by the servo motor 14 to place the second eccentric shaft 17 as shown in
Between any two adjacent spiked peripheral drive wheels 27 on the shaft 26 is disposed a nose bar 29 serving as a pressure member which is mounted at the top portion thereof to a pressure bar block 1a, as shown in
Between any two adjacent peripheral drive wheels 27 is also disposed a separating member 8 which is mounted to the nose bar block 1a, as shown in
As shown in
Referring again to
A support block 46 is fixed to the nose bar block 1a, projecting therefrom in the same direction as the engagement member 45, and a reversible servo motor 47 is mounted on the support block 46 and connected to the control unit 5. A screw or a threaded rod 48 is operatively connected to the servo motor 47 and engaged with an internally threaded hole (not shown) formed in a stop member 50, so that rotation of the servo motor 47 and hence of the screw 48 causes the stop member 50 to move relative to the knife carriage 1 along a linear bearing 49 in either of the arrow directions (
Thus, the arm 19 is swingable about the shaft portion 9a in opposite arrow directions by extension and retraction of the piston rod 43a of the hydraulic cylinder 43, thereby making it possible for the peripheral drive wheels 27 to move toward and away from the wood block 3.
Referring to, e.g.,
A shown in
As shown in
Though
In operation, the servo motor 53 responding to a control signal from the control unit 51 drives to rotate the lead screws P at such a rate that the knife carriage 1 is moved toward the wood block 3 supported by the spindles 2 for a distance corresponding to the thickness of veneer sheet to be peeled by the knife 5 for each complete turn of the wood block 3. Receiving information from the absolute encoder 52 which is indicative of the current spaced distance between the axial center of the spindles 2 and the cutting edge of the knife 5, the control unit 52 generates a control signal to drive the servo motor 2a such that the speed of the spindles 2 is increased in inverse proportion to the above spaced distance so that the peripheral speed of the wood block 3 at the point of cutting by the knife 5 may be substantially constant. Furthermore, the control unit 52 generates signals to control the operation of servo motors 14, 47 and other devices of the lathe in response to a signal generated from manual operation by lathe operator and also to preset signals as will be described more in detail hereinafter.
The following will describe a method of cutting a wood block for peeling veneer therefrom by way of explaining the operation of the above-described veneer lathe.
Referring to
For accomplishing this position of the peripheral drive wheels 27, with the hydraulic cylinder 43 set in inoperative state or no pressure acting on its piston rod 43a, the motor 14 (
With the hydraulic cylinder 43 actually activated, the engagement member 45 is kept pressed against the stop member 50. Furthermore, the control unit 51 is set such that the knife carriage 1 is moved by operation of the servo motor 53 toward a wood block 3 for a distance of 4 mm for each complete turn of the spindles 2. The spindles 2 are operated to move toward each other thereby to hold the wood block 3 at the axial center of the opposite ends thereof.
In response to a start signal provided manually by lathe operator, the control unit 51 generates a control signal to activate the servo motor 2a to drive the spindles 2 thereby to rotate the wood block 3, and also to activate the servo motor 35 to rotate the peripheral drive wheels 27. Simultaneously, the servo motor 53 is also operated to controllably rotate the screws P. Thus, the knife carriage 1 is moved toward the wood block 3 at a speed or a feedrate which is determined by the control unit 51 depending on the rotational speed of the spindles 2 and the spaced distance between the axial center of the spindles 2 and the cutting edge of the veneer peeling knife 5.
In the meantime, the knife 5 and the rotating peripheral drive wheels 27 are brought into engagement with the periphery of the wood block 3 and veneer begins to be peeled from the block 3 by the knife 5, as shown in
However, since the power of the spindle 2 is insufficient for driving the wood block 3 by itself for cutting veneer therefrom, the peripheral speed of the wood block 3 is decreased by the cutting resistance exerted by the knife 5 and, therefore, the peripheral speed of the peripheral drive wheels 27 is decreased with the slow-down of the wood block 3. When the peripheral speed of the peripheral drive wheels 27 at the tip ends of the projections 27a is reduced to a predetermined value, power of the peripheral drive wheels 27 is then transmitted to the block 3 because of the action of the one-way clutch and veneer with a thickness of about 4 mm is peeled by the knife 5 from the rotating wood block 3. During this initial period of peeling operation, veneer strips with various narrow widths are produced before the wood block 3 becomes substantially cylindrical by round-up peeling.
In
Additionally, the splits are enlarged and also new splits are formed in the veneer strip V when it moves past the separating members 8 and is bent downward in contact with the lower surfaces 8a of the separating members 8. The veneer strips V thus produced have very little curling because of such splits.
Once the wood block 3 has become cylindrical, a continuous sheet of veneer V is produced. In response to a signal transmitted by manual operation of the lathe operator who then recognizes that peeling of a continuous veneer sheet V from the wood block 3 has begun, the control unit 51 causes the servo motor 14 (
As a result, the peripheral drive wheels 27 are positioned with the tip ends of their projections 27a spaced at a distance of about 4.5 mm from the top surface 6b of the guide members 6, as shown in
A continuous width of veneer sheet having reduced splits tends to be curled. Unlike veneer strips with narrow widths, veneer sheet having a continuous width poses very little problem in the subsequent processes because such veneer sheet as peed by rotary veneer lathe is usually wound or reeled into a roll by a reeling machine and the veneer sheet produced as shown in
Since the diameter of the wood block 3 is reduced progressively as the veneer peeling operation is continued, the relation of the peripheral drive wheels 27 to the wood block 3 is varied. Specifically, as the block diameter is reduced to such an extent that the outer periphery of the wood block 3 is changed, for example, as indicated by chain double-dashed arcuate line Z-Z in
According to the illustrated embodiment of the present invention, however, after the peripheral drive wheels 27 are moved to their raised position (
Therefore, the spiked peripheral drive wheels 27 are moved toward the wood block 3 continuously with a decrease in the above spaced distance between the axial center of the spindles 2 and the cutting edge of the veneer knife 5, with the result that the number of projections 27a engaging with the peripheral surface of the wood block 3 is not reduced remarkably and also that the projections 27 pierce deeper into the wood block, as shown in
The rate at which the stop member 50 is moved toward the knife 5 relative to the knife carriage 1 may be set according to the desired number of projections 27a to pierce into the wood block 3 and the desired piercing depth of the projections 27a.
When the absolute encoder 52 determines that the spaced distance between the axial center of the spindles 2 and the cutting edge of the veneer knife 5 is reduced by veneer peeling to a predetermined value, it generate a signal to the control unit 51, which then provides a control signal which causes the servo motor 53 to be stopped and then driven reverse so that the screws P are stopped and then rotated reverse, accordingly. The knife carriage 1 is moved by the servo motor 53 away from the wood block 3 until a standby position is reached which is determined by the absolute encoder 52.
After the knife carriage 1 has stopped at the standby position, the servo motor 47 is driven reverse to rotate the screw 48 for swinging the arm 19 and hence the spiked peripheral drive wheels 27 back to their retracted position as shown in
As a matter of course, the peripheral drive wheels 27 must be so arranged that their tooth-like projections 27a will not be brought into contact with the cutting edge of the knife 5 when the drive wheels 27 are moved closest to the knife 5.
It is noted that, according to the present invention, the spiked peripheral drive wheels 27 may be moved toward the knife 5 irrespective of the spaced distance between the axial center of the spindles 2 and the cutting edge of the veneer knife 5 so that the drive wheels 27 are moved closest to the knife 5 before the above spaced distance becomes a predetermined minimum value. Alternatively, the spiked wheels 27 may be moved closest to the knife 5 immediately after the drive wheels 27 are moved to their raised position of
The following will describe a second embodiment of the present invention.
The arrangement of veneer lathe for the second embodiment is substantially the same as that for the above-described first embodiment. The lathe is initially set in the same manner as in the first embodiment and the peripheral drive wheels 27 are set in their lowered position. The servo motor 2a is driven to rotate the spindles 2 and hence the wood block 3, and the servo motor 36 is also driven thereby to rotate the peripheral drive wheels 27. Then the servo motor 53 is operated to controllably rotate the screws P for moving the knife carriage 1 toward the wood block 3, thus veneer strips with narrow widths and a thickness of about 4 mm are produced as in the first embodiment. Such veneer strips have formed therein many large or substantial splits and, therefore, have little curling.
As the lathe operator recognizes that a continuous veneer sheet V has begun to be peeled from the wood block 3 and manually provides a signal to the control unit 51, the servo motor 14 is driven thereby to rotate the first shaft 9 for an angle of 180°. Accordingly, the eccentric shaft 17 is turned to the position of
According to this second embodiment, when the spaced distance between the axial center of the spindles 2 and the cutting edge of the knife 5 is reduced to a preset value which is determined by the absolute encoder 52, the servo motor 14 is operated to turn the first shaft 9 for further 180° thereby to move the spiked peripheral drive wheels 27 to their lowered position. By so doing, the relation of the peripheral drive wheels 27 to the wood block 3 becomes as shown in
Thus, formation of the above-described circumferential grooves by the tooth-like projections 27a of the peripheral drive wheels 27 is prevented and, therefore, the force from the drive wheels 27 necessary for veneer peeling continues to be transmitted to the block 3 for smooth veneer peeling operation.
Veneer sheet produced with the peripheral drive wheels 27 placed in their lowered position as shown in
The following will describe a third embodiment of the present invention.
As in the cases of the above first and second embodiments, the peripheral drive wheels 27 are initially placed in their lowered position of
According to the third embodiment, the servo motor 47 is then operated to move the stop member 50 toward the veneer knife 5 relative to the knife carriage 1 depending on the spaced distance between the axial center of the spindles 2 and the cutting edge of the veneer knife 5 which is determined by the absolute encoder 52. As a result, the arm 19 is swung about the shaft 17 thereby to move the spiked peripheral drive wheels 27 toward the wood block 3 continuously with a decrease in the above spaced distance between the axial center of the spindles 2 and the cutting edge of the veneer knife 5, as in the first embodiment, so that, as compared with the case of the second embodiment of
As in the first embodiment, the rate at which the stop member 50 is moved toward the knife 5 relative to the knife carriage 1 may be set according to the desired number of projections 27a to pierce into the wood block 3 and the desired piercing depth of the projections 27a, and the peripheral drive wheels 27 must be so arranged that their tooth-like projections 27a will not be brought into contact with the cutting edge of the knife 5 when the drive wheels 27 are moved as far as they can.
The following will describe a fourth embodiment of the present invention. This embodiment is advantageously applicable in peeling veneer from a substantially cylindrical block which is previously rounded by a rotary veneer lathe or any cutter or from a block having a small diameter of about 200 mm.
The arrangement of veneer lathe for the fourth embodiment is substantially the same as that for the first embodiment. Unlike the first and second embodiments, the peripheral drive wheels 27 are initially set in their raised position. In operation, the knife carriage 1 is moved toward a rotating wood block 3 at a desired feedrate, and the peripheral drive wheels 27 are moved relative to the knife carriage 1 toward the wood block 3 according to the information from the absolute encoder 52 that is indicative of the current spaced distance between the axial center of the spindles 2 and the cutting edge of the knife 5, as in the first embodiment.
A veneer sheet cut according to the method of this fourth embodiment and moving past the guide members 6 is not subjected to tensile force by the projections 27a of the drive wheels 27 which causes substantial splits in the veneer sheet. Thus, the veneer sheet is formed only with little splits. Only small splits are formed in the veneer sheet V when it moves past in contact with the surfaces 8a of the separating members 8.
When a cylindrical wood block is rotary cut by a veneer lath, a continuous sheet of veneer is produced from the beginning of veneer peeling and such veneer sheet is reeled into a roll by a reeling machine, as described earlier with reference to the first embodiment.
Veneer strips with narrow widths peeled from a non-cylindrical wood block with a smaller diameter tend to be curled in such a way that the surface of veneer strip on the side that is adjacent to the peripheral drive wheels 27 when it is just cut by the knife lies outside of the curl. This is due to a greater difference in length between the above side of veneer strip and the opposite side thereof of a veneer strip cut from a wood block with a smaller diameter. Therefore, the curling developed by splits formed during veneer peeling is offset by the above tendency of curling, so that veneer strips with narrow widths peeled from a wood block having a small diameter of about 200 mm has little curling.
As an alternative of this fourth embodiment, the servo motor 14 may be operated to turn the first shaft 9 for 180° thereby to move the peripheral drive wheels 27 to their lowered position when the wood block 3 is further cut to a predetermined diameter. By so moving the drive wheels 27, the relation of the drive wheels 27 to the wood block 3 becomes as shown in
As a further alternative embodiment, after the peripheral drive wheels 27 are lowered, the servo motor 47 may be operated to move the stop member 50 toward the veneer knife 5 according to the information from the absolute encoder 52 so that the peripheral drive wheels 27 are moved relative to the knife carriage 1 toward the wood block 3 continuously with a further decrease in the block diameter.
Although the foregoing has described the present invention by way of specific embodiments, it is to be understood that the present invention is not limited to those embodiments, but the invention can be practiced in various changes and modifications, as exemplified below.
Referring to
According to the embodiment of
In the first embodiment, if any wood piece or debris is held and moved past between the wood block 3 and the peripheral drive wheels 27 during peeling operation, the presence of such wood piece creates a force against both the peripheral drive wheels 27 and the wood block 3, which force may cause the block 3 to be broken or some of the tooth-like projections 27a of the peripheral drive wheels 27 or any member supporting such drive wheels 27 to be damaged. In the modified embodiment of
In each of the foregoing embodiments, the spiked peripheral drive wheels 27 in their lowered position may be moved to a raised position as shown in
When shifting the spiked peripheral drive wheels 27 between the raised and lowered positions thereof, the feedrate of the knife carriage 1 or the distance the knife 5 cuts into a rotating wood block 3 for each complete turn of the block 3 may be changed so that veneer with a different thickness is peeled after the shifting of the peripheral drive wheels position. Additionally, veneer peeling operation does not necessarily have to be performed uninterruptedly, but the knife carriage 1 may be stopped thereby to interrupt the peeling operation when changing the position of the peripheral drive wheels 27 between the raised and lowered positions thereof.
In the aforementioned first and third embodiments, the peripheral drive wheels 27 may be moved relative to the knife carriage 1 toward the wood block 3 by the hydraulic cylinder 43 irrespective of the reduction of wood block diameter. For example, the drive wheels 27 may be moved at once as far as it will go within its predetermined stroke toward wood block 3.
The mechanism for moving the spiked peripheral drive wheels 27 relative to the knife carriage toward and away from the wood block 3, which includes hydraulic cylinder 43, engagement member 45, stop member 50, servo motor 47 and other parts and devices, may includes a plurality of such mechanism units which are arranged at a spaced interval along the shaft portion 25 and operable simultaneously.
In the above-described embodiments, a pair of first and second backup rolls 71 and 73 may be used for supporting a wood block 3 and also preventing deflection thereof. The first roll 71 extends along the axial direction of the wood block 3 and disposed on the opposite side of the wood block 3 to the peripheral drive wheels 27. The roll 71 is movable horizontally radially, as shown by arrow, in rotational contact with the peripheral surface of the block 3 according to a control signal from the control unit 51 which receives information from the absolute encoder 52 while the block 3 is reduced in diameter by continued veneer peeling. On the other hand, the second backup roll 73 which also extends axially of the wood block 3 and is disposed at the bottom of the block 3 is movable vertically radially, as shown by arrow, while keeping rotational contact with the periphery of the wood block 3 while it is reduced in diameter.
In the rotary veneer lathe equipped with such backup rolls 71, 73, the spaced distance between the axial center of the spindles 2 and the cutting edge of the knife 5 is reduced to a predetermined value after a continuous veneer sheet has begun to be peeled from the wood block 3, the spindles 2 are retracted or moved away from the opposite ends of the wood block 3 so that the block 3 is supported only by the backup rolls 71, 73 and the peripheral drive wheels 27. As is obvious to those skilled in the art, the use of such backup rolls 71, 73 makes possible cutting a wood block down to a core diameter that is smaller than that of the spindles 2, with the result that the overall veneer yield is further increased.
If the peripheral drive wheels 27 are moved from the lowered position to the raised position while the wood block 3 is supported by the backup rolls 71, 73 and the drive wheels 27, the block 3 is also moved upward and failure in veneer peeling occurs. To prevent such situation, the block 3 should be supported by the spindles 2 when moving the peripheral drive wheels 27 upward, and the spindles 2 may be retracted from the block 3 when the movement of the drive wheels 27 is completed.
As means for supporting the wood block 3 other than the spindles 2, a plurality of rolls, at least one of which is positively driven, may be arranged round and in contact with the peripheral surface of the block 3.
In the middle of cutting a wood block for veneer peeling with the peripheral drive wheels 27 placed in either of the lowered or raised position or with the drive wheels 27 being moved relative to the knife carriage 1 toward the wood block 3, the feedrate of the knife carriage 1 and hence the thickness of veneer to be peeled may be changed by appropriate manual operation of the lathe operator.
The spiked peripheral drive wheel 27 may be designed according to any specific requirements. For example, the shape of the tooth-like projections 27a and the circumferential spaced distance between any two projections 27a may be changed as required. The number of peripheral drive wheels 27 on the shaft 26 and the spaced distance of such drive wheels 27 in the axial direction of the shaft 26 may be changed according to any specific requirement.
The eccentric shaft 17 or the hydraulic cylinder 43 for moving the peripheral drive wheels 27 may be replaced by any suitable means such as cam.
Though the guide member 6 of the foregoing embodiments is disposed between any two adjacent peripheral drive wheels 27, each guide member 6 may be arranged in a directly facing relation to a peripheral drive wheel 27.
For the veneer V moving past the guide members 6 to be free from the influence of tensile force by the projections 27 of the peripheral drive wheels 27, the spaced distance between the tip ends of the projections 27a and the top surfaces 6a of the guide members 6 should be greater than the thickness of veneer to be peeled. For the veneer V to move past the guide members 6 smoothly, however, the above spaced distance may be reduced to such an extent that the projections 27a pierce about 0.5 mm into the veneer V. Tensile force created by this extent of piercing of the projections 27a does not cause substantial splits in the veneer V.
A rotary veneer lathe shown in
Number | Date | Country | Kind |
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P2003-426729 | Dec 2003 | JP | national |