Installation, method for cutting logs and assembly comprising such an installation

Abstract

Installation (1) for cutting logs (20) of wood comprising an uncoiler (2) having a location (4) for receiving a log (20) of wood, a motor device (5) for driving the log (20) of wood in rotation inside said location (4) around an axis (XX') of rotation for rotation of the log (20) and at least one cutting member (6) mounted movable in the direction of the axis (XX') of rotation and configured to allow, as the log (20) is driven in rotation, the obtaining at the output of the uncoiler (2) of a strip (21) of wood.The installation (1) includes a visualization system (7) for detecting wood defects, a system (8) for determining a parameter representative of the speed of movement of the wood strip (21), a device (9) for cutting the wood strip (21) in a direction parallel to the axis (XX') of rotation of the log to form at least one strip segment, and a control unit (10) configured to control the device (9) for cutting the strip (21) into strip segments according to the data provided by said systems (7, 8). Figure for the abstract: Fig. 1.

Description

Title of the invention: Installation, method for cutting logs and assembly comprising such an installation

[0001] The present invention relates to an installation and a method for cutting logs, as well as an assembly comprising such an installation.

[0002] It relates in particular to an installation for cutting logs for the purpose of manufacturing planks, said installation comprising at least one uncoiler, said uncoiler comprising a frame with a location for receiving a log, a motor device for rotating the log inside said location around an axis of rotation corresponding to a so-called longitudinal axis of the log for rotation of the log and at least one cutting member mounted movable in the direction of the axis of rotation and configured to allow, as the log is rotated, the production of a strip of cuttable wood at the output of the uncoiler, said strip having at the output of the uncoiler a so-called longitudinal axis orthogonal to the axis of rotation of the log.

[0003] Uncoiling machines for obtaining a strip of wood are well known to those skilled in this field, as illustrated by patent EP 2,324,978. Similarly, it is known to cut a strip of wood to produce boards. Until now, these operations have been completely separate, and the strip of wood is generally re-wound after exiting the uncoiling machine and then processed elsewhere. Since the strip of wood may contain defects, the boards produced from it may also have defects. Therefore, the boards are visually sorted by an operator after being cut into boards. This operator generally removes and discards the defective boards manually. These operations are tedious and generate stress and musculoskeletal disorders for the operator. Moreover, the quantity of waste is particularly significant.

[0004] An object of the invention is to propose an installation of the aforementioned type whose design allows for optimization of the processing of a log in order to reduce the number of rejects, in particular when the strip of wood is intended for the manufacture of boards, without affecting the production rate.

[0005] Another object of the invention is to provide an installation whose design makes it possible to reduce stress and musculoskeletal disorders at the operator level as well as the number of operators.

[0006] To this end, the invention relates to an installation for cutting logs, said installation comprising at least one uncoiler, said uncoiler comprising a frame with a log reception location, a motor device for rotating the log within said location around an axis of rotation corresponding to a so-called longitudinal axis of the log for rotation of the log about itself, and at least one cutting member mounted movable in the direction of the axis of rotation and configured to allow, as the log is rotated, the production at the uncoiler of a strip of cuttable wood with a so-called longitudinal axis orthogonal to the axis of rotation of the log, characterized in that the installation comprises a visualization system for detecting defects in the wood,a system for determining a parameter representative of the speed of movement of the wood strip, a device for cutting the wood strip along a direction parallel to the axis of rotation of the log, i.e., transverse to the longitudinal axis of the strip to form at least one strip segment, and a control unit, in that the visualization system is arranged upstream of the device for cutting the wood strip into strip segments relative to the direction of movement of the wood strip, and in that the control unit is configured to control the device for cutting the wood strip into strip segments based at least on the data provided by the visualization system for detecting wood defects and the system for determining a parameter representative of the speed of movement of the wood strip.

[0007] A log is defined as a piece or block of wood, generally cylindrical in shape. Positioning the visualization system upstream of a strip cutting device allows for early detection of defects, thus optimizing their management. The control unit's ability to acquire data from the visualization system and data relating to the strip's travel speed to control the strip cutting device makes it easy to determine the position of defects in real time and continuously, thereby optimizing the strip cutting process. Since the cutting can be optimized in this way, it is possible to obtain strip sections that are reliably free of defects, which facilitates their subsequent processing.

[0008] According to one embodiment of the invention, the installation comprises a path for the wood strip coming from the uncoiler, and the device for cutting the wood strip into strip segments is arranged on said path. Preferably, the viewing system is arranged on said path, upstream of the device for cutting the strip into strip segments, relative to the direction of movement of the strip on said path.

[0009] According to one embodiment of the invention, the visualization system for detecting wood defects includes at least one image-capturing device, such as a camera, directed towards the receiving location of the log and / or towards the path of the strip coming from the uncoiler to visualize an area called the image-capturing area.

[0010] According to one embodiment of the invention, the system for determining a parameter representative of the speed of movement of the wooden strip comprises at least a first device for measuring the speed of rotation of the wooden log and a second device for determining the position of the cutting element and the control unit is configured to, as a function of the data of the first and second devices, determine by calculation the so-called linear speed of the strip at the exit of the uncoiler and consequently the position of one of the so-called driving ends of the strip opposite to that connected to the wooden log.

[0011] The control unit is therefore configured to calculate, based on data from the first and second devices, the linear speed of the strip exiting the unwinder and consequently determine in real time and continuously the position of one of the strip's ends, called the leading end, opposite the end connected to the ball. The relative position of the cutting device and the visualization system is predetermined. It is therefore easy to determine the optimal cutting time with regard to the position of the leading end and the data provided by the visualization system, and to optimize the strip cutting time based on the data provided by the visualization system to obtain strip sections with or without defects.

[0012] According to one embodiment of the invention, the control unit is configured to control the wood strip cutting device into strip sections based at least on the data provided by the visualization system and the position of the leading end of the strip itself as a function of the linear speed of the strip.

[0013] Ideally, the motor device for driving the rotation of the log and the movement of the cutting element are controlled so that the linear speed of the strip at the output of the uncoiler is substantially constant, i.e. with a variation of the linear speed over time of less than 10% once the initialization phase is completed, i.e. after at least one rotation of the log.

[0014] According to one embodiment of the invention, the control unit is configured to, when a wood defect is detected by the visualization system, determine the position of the defect relative to the position of the leading end of the strip and control the strip cutting device based on at least the position of the defect relative to the position of the leading end of the strip to obtain a strip section whose length is a function at least of the position of the defect relative to the position of the leading end of the strip.

[0015] According to one embodiment of the invention, the installation is equipped with a storage memory for at least one setpoint length of a belt segment. Said length is taken along a direction orthogonal to the axis of rotation of the ball, that is to say along the longitudinal axis of the belt.

[0016] According to one embodiment of the invention, the installation includes at least a first, a second and a third outlet for the evacuation of a section of strip to allow, at the level of said first outlet, the evacuation of a section of strip having a defect and a length less than the set length, at the level of said second outlet, the evacuation of a section of strip free of defect and of a length less than the set length and at the level of said third outlet the evacuation of a section of strip free of defect and of a length equal to the set length.

[0017] According to one embodiment of the invention, the installation includes a switch arranged between the wood cutting device and said first, second and third exits.

[0018] According to one embodiment of the invention, the switch is arranged at the end of the path of the strip coming from the unwinder and forms a movable part of said path which can be selectively positioned opposite one of the first, second and third exits.

[0019] According to one embodiment of the invention, the installation includes an additional cutting device for cutting at least some of the strip sections into boards.

[0020] The invention further relates to an assembly comprising at least one log and an installation for cutting said log, characterized in that the installation conforms to that described above.

[0021] The invention further relates to a method for cutting logs, particularly for the manufacture of planks, using a log cutting installation comprising at least one uncoiler, said uncoiler comprising a frame with a log reception area, a device for driving the log within said area to rotate it around an axis of rotation corresponding to a so-called longitudinal axis of the log, and at least one cutting member mounted movable in the direction of the axis of rotation and configured to allow, as the log is driven in rotation, the production of a cuttable strip of wood at the outlet of the uncoiler, said strip having at the outlet of the uncoiler with a so-called longitudinal axis orthogonal to the axis of rotation of the log, characterized in that the installation for cutting the log being in accordance with that described above, the method includes a step of visualizing the log and / or the strip resulting from the uncoiling in order to detect wood defects, a step of determining a parameter representative of the speed of movement of the wood strip and a step of transverse cutting (i.e. orthogonally to its longitudinal axis) of the strip into at least one strip section according to the data provided during the steps of visualizing and determining a parameter representative of the speed of movement of the wood strip.

[0022] According to one embodiment of the invention, the step of determining a parameter representative of the speed of movement of the wood strip includes a step of measuring the speed of rotation of the log and determining the position of the cutting element, a step of determining from said data the so-called linear speed of the strip at the exit of the uncoiler and consequently the position of the driving end of the strip opposite to that connected to the log to allow when a wood defect has been visualized during the visualization step, to determine the position of said defect relative to the driving end of the strip and during the step of cutting the strip, the strip is cut according to at least the data provided during the visualization step and the position of the driving end of the strip itself as a function of the linear speed of the strip, the position of the cutting device of the strip being predetermined and known.

[0023] According to one embodiment of the invention, a set length of strip section being memorized, the process includes, during the strip cutting step, a cutting of either a strip section having a defect and of a length less than the set length, or of a strip section free of defect and of a length less than the set length, or of a strip section free of defect and of a length equal to the set length.

[0024] According to one embodiment of the invention, the installation comprising at least a first, a second and a third outlet for the evacuation of a strip section and a switch disposed between the wood strip cutting device and said first, second and third outlets, the method comprises, after the operation of cutting the strip into a strip section, a strip section switching step to allow at said first outlet an evacuation of a strip section having a defect and a length less than the set length, at said second outlet an evacuation of a strip section free of defect and of a length less than the set length and at said third outlet an evacuation of a strip section free of defect and of a length equal to the set length. Brief description of the drawings

[0025] The invention will be better understood upon reading the following description of exemplary embodiments, with reference to the accompanying drawings in which:

[0026] [Fig-1] represents a schematic front view of an installation conforming to the invention;

[0027] [Fig.2] represents a schematic top view of an installation conforming to the invention;

[0028] [Fig.3] represents a schematic front view of part of the installation extending from the unwinder to the cutting device;

[0029] [Fig.4] represents a schematic front view of part of the installation extending from the cutting device to the production of boards.

[0030] As mentioned above, the installation 1 is intended for cutting a log 20 of wood to optimize its processing. As illustrated in [Fig. 1], this installation 1 includes an uncoiler 2 on which the log 20 of wood to be cut is placed.This uncoiler 2 comprises a frame 3 with a receiving position 4 for a wooden log 20, a motor device 5 for driving the rotation of the wooden log 20 inside said position 4 around an axis XX' of rotation corresponding to a so-called longitudinal axis of the wooden log 20 for a rotation of the wooden log 20 about itself, and at least one cutting member 6 mounted movable in the direction of the axis XX' of rotation and configured to allow, as the wooden log 20 is driven in rotation, the obtaining at the output of the uncoiler 2 of a cuttable strip 21 of wood, said strip 21 having at the output of the uncoiler 2 a so-called longitudinal axis YY' orthogonal to the axis XX' of rotation of the wooden log 20.

[0031] Such an unwinder 2 is well known to those versed in this art, and an example of an unwinder is notably provided in patent EP2324978.

[0032] The motor-driven device 5 for rotating the wooden log 20 may thus comprise a spindle 51 in one or more elements arranged inside the log 20 receiving position 4 of the uncoiler 2. This spindle 51 is designed to extend along the central longitudinal axis of the log 20 in the positioned state of the wooden log 20, which is in the form of a generally cylindrical block of wood on said spindle. All or part of the spindle 51 may be motorized to ensure the rotational drive of the log 20.

[0033] Guiding elements 52, such as rollers or rollers, are arranged in the ball receiving position 4 and are configured to extend around the periphery of the ball to assist in guiding and, if necessary, in rotating the wooden ball 20, again in a manner known to itself, when rotating The ball is operated partly from the periphery of the wooden ball 20. These guide elements 52 can also form the rotational drive elements of the wooden ball 20.

[0034] Regardless of whether the drive is central or peripheral, the objective is always to rotate the wooden ball 20 around an axis coaxial with the spindle 51, referred to as the ball's rotation axis XX', thus rotating the wooden ball 20 about its own axis. In summary, the wooden ball receiving location 4 includes a spindle 51. The motor device 5, which drives the rotation of the wooden ball 20, is configured within said location 4 to rotate the wooden ball around an axis XX' coaxial with the spindle 51.

[0035] The cutting element 6 equipping the uncoiler 2 can be in the form of an uncoiling knife whose cutting edge contacts the wooden log 20 at the periphery of said log 20. This uncoiling knife can be arranged on a carriage for a mobile mounting, allowing the cutting element 6 to move along the axis XX' of rotation of the log 20 as the log is uncoiled. Again, such a carriage is well known, as illustrated by patent EP2324978.

[0036] The combined action of the rotational drive of the wooden log 20 and the movement of the cutting member 6 makes it possible, in a manner known in itself, to obtain at the output of the uncoiler 2 a strip 21 of wood whose longitudinal axis YY' is orthogonal to the axis XX' of rotation of the log 20, that is to say orthogonal to the spindle 51 of the uncoiler 2. This strip 21 of wood advances as the rotational drive of the wooden log 20 progresses.

[0037] Generally, the installation 1 is, as illustrated in [Fig. 3], equipped at the outlet of the uncoiler 2 with a path 11 for the flow of the strip 21 coming from the uncoiler 2. The movement of the wooden strip 21 resulting from the rotation of the log 20 can be guided along this path 11. For this purpose, the path 11 for the flow of the wooden strip 21 can be equipped with means for movement to form a moving path for transporting the wooden strip 21. The path 11 for the flow of the wooden strip 21 is, in the example of [Fig. 1], a conveyor in the form of a conveyor belt.

[0038] The installation 1 includes a system 8 for determining a parameter representative of the speed of movement of the wooden strip 21. This speed of movement of the wooden strip 21 is a function of the rotational drive speed of the wooden log 20 and the diameter of the wooden log 20 as a function of the position of the cutting member 6.

[0039] The installation therefore includes a system 8 for determining a parameter representative of the speed of movement of the wooden strip 21 which includes at less a first device 81 for measuring the rotation speed of the ball and a second device 82 for determining the position of the cutting member 6.

[0040] Installation 1 includes a control unit 10. This control unit 10 is in the form of an electronic and computer system which includes, for example, a microprocessor and working memory. In one particular aspect, the control unit may be in the form of a programmable logic controller (PLC). In other words, the functions and steps described may be implemented either as a computer program or via hardware components (e.g., programmable gate networks).In particular, the functions and steps performed by the control unit or its modules can be carried out by instruction sets or computer modules implemented in a processor or controller, or by dedicated electronic components, or by components such as field-programmable gate arrays (FPGAs), or application-specific integrated circuits (ASICs). It is also possible to combine computer and electronic components.When it is specified that the unit or means or modules of said unit are configured to perform a given operation, this means that the unit includes computer instructions and the corresponding means of execution which enable said operation to be performed and / or that the unit includes corresponding electronic components.

[0041] The control unit 10 is therefore configured to, based on the data from the first and second devices 81 and 82, determine by calculation the so-called linear speed of the wood strip 21 at the exit of the uncoiler 2 and, consequently, the position of one of the so-called driving ends of the wood strip 21 opposite to the end of the strip connected to the log 20. This driving end is represented in 22 in the figures.

[0042] The control unit 10 is also configured to control the belt rotation drive motor 5 and the movement drive of the cutting element 6, so that the linear speed of the wood belt 21 is substantially constant. It is thus easy to implement the travel path 11 as a transport path for the wood belt 21, the control unit 10 being configured to drive this transport path at a speed identical to the linear speed of the belt determined from the data provided by the system 8 for determining a parameter representative of the movement speed of the wood belt 21.

[0043] The first device 81 for measuring the rotational speed of the ball 20 can be formed by an angular encoder integrated, for example, into the spindle 21.

[0044] The second device 82 for determining the position of the cutting member 6 can be a linear sensor capable of detecting the position of the cutting member 6 as it moves. The data from its first and second devices are acquired by the control unit 10. The control unit 10 is configured to, based on the data from the first and second devices 81 and 82, calculate the linear speed of the strip 21 exiting the unwinder 2 and consequently the real-time, continuous position of one of the leading ends 22 of the strip 21 opposite the end connected to the ball 20.

[0045] The installation includes a visualization system 7 for detecting wood defects. This wood defect, represented by 25 in the figures, may consist of an incorrect thickness, an incorrect length, an incorrect width, an incorrect geometry, the presence of a hole in an undesirable location, an excessively large hole, the presence of a knot, the presence of a crack, the presence of splintering, a flash (splinters, uneven edges)... This visualization system 7 for detecting wood defects includes at least one image-capturing device 71, such as a camera, oriented towards the receiving location 4 for the log 20 and / or towards the path 11 of the strip 21 coming from the uncoiler 2 to visualize an area 72 called the image-capturing area 72. The relative position of the visualization system 7, in particular of the image-capturing area 72, and of the device 9 for cutting the wood strip 21 is predetermined and known.so that the control unit 10, which is configured to control the device 9 for cutting the wood strip 21 into strip segments based at least on the data provided by the visualization system 7 and the position of the driving end 22 of the strip 21, itself a function of the linear speed of the strip 21, is configured to, when a wood defect is detected by the visualization system 7, determine the position of the defect relative to the position of the driving end 22 of the strip 21 and control the strip cutting device 9 based at least on the position of the defect relative to the position of the driving end 22 of the wood strip 21 to obtain a strip segment of length that is a function at least of the position of the defect 25 relative to the position of the driving end 22 of the wood strip.

[0046] The detection and visualization of a defect by the control unit 10 is carried out in a conventional manner by comparing the images obtained at the shooting zone 72 with an image library to determine the presence or absence of a defect. Once the defect is detected, it is easy, based on the time of shooting, to determine its position relative to the position of the leading end 22 of the strip and to control the cutting device 9 accordingly.

[0047] Generally, the installation 1 is equipped with a memory 12 for storing at least one setpoint length of a strip segment. This length is taken according to a direction orthogonal to the axis of rotation, that is to say along the longitudinal axis of the strip 21 of wood.

[0048] The objective is to obtain a maximum number of defect-free strip sections of equal length to the target length.

[0049] The control unit 10 is therefore configured to optimize the cutting of the wood strip 21, depending on the position of the defect relative to the leading end 22 of the wood strip. The control unit 10 can thus command the cutting of the wood strip 21 into three types of strip sections, namely, either a strip section 231 with a defect and shorter than the set length, or a strip section 232 free of defects and shorter than the set length, or a strip section 233 free of defects and equal to the set length.

[0050] The installation therefore comprises, as illustrated in [Fig. 4], at least one first discharge outlet 13, a second discharge outlet 14, and a third discharge outlet 15. Each discharge outlet allows the discharge of a section of the belt. The first outlet 13 allows the discharge of a section of the belt 231 that has a defect and is shorter than the specified length. The second outlet 14 allows the discharge of a section of the belt 232 that is free of defects and shorter than the specified length. The third discharge outlet 15 allows the discharge of a section of the belt 233 that is equal to the specified length and free of defects.

[0051] To allow the selective feeding of one of these first, second, and third evacuation outlets, the installation includes a switch 16 located between the wood-cutting device 9 and said first, second, and third outlets. This switch 16 is located at the end of the path 11 of the belt 21 coming from the unwinder 2 and forms a movable part of the path 11 that can be selectively positioned opposite one of the first, second, and third evacuation outlets of the belt section.

[0052] In the example of [Fig. 4], this switch 16 is a pivoting conveyor belt mounted to pivot about an axis perpendicular to the direction of movement of the wooden strip, that is, parallel to the axis XX' of rotation of the log 20. This conveyor belt is, during its pivoting movement, driven by the control unit 10 to be positioned opposite any one of the outlets. Each outlet for the section of the belt includes, in the example shown, a collection bin.

[0053] The installation 1 includes an additional cutting device 17 for cutting at least some of the strip sections into boards 24. This additional cutting device 17 comprises, in the example shown in Figures 1 and 4, a guillotine cutter to allow cutting the section 233 of defect-free strip of equal length to the specified length into board 24 and a manipulator to allow the storage of the boards in a new collection bin.

[0054] To complete this installation 1, a detection cell 18 can be provided on the path 11 of the conveyor belt 21 coming from the uncoiler, upstream of the visualization system 7 (which is positioned relative to the direction of travel of the wood belt 21). This cell detects the leading end 22 of the wood belt and participates in the initialization of the installation 1 to determine the actual position of the leading end 22 at a given time. From this actual position of the leading end, determined during the initialization phase of the installation 1, the control unit 10 can then calculate, in real time and continuously, the position of the leading end 22 of the wood belt 21. The presence of this detection cell 18 is not mandatory, but it allows for confirmation of information that would have been determined by calculation.

[0055] The operation of such an installation 1 is extremely simple. A log 20 is positioned in the designated log receiving slot 4. The log 20 is then rotated by the log rotation drive device 5, while the cutting element 6 is moved along the axis XX' of rotation of the log. This results in the formation of a strip of wood at the output of the uncoiler 2.

[0056] This wooden strip 21 rests on the travel path 11 located at the exit of the uncoiler 2, and advances as the log is rotated. This movement can be accompanied by the travel path 11 when this travel path 11 is also a transport path.

[0057] The wooden strip 21 passes through the shooting area 72 of the viewing system 7, the viewing system 7 being, in the example of [Fig.1], arranged above the traffic path 11.

[0058] Alternatively, the viewing system 7 could have been directly oriented towards the wooden ball to view the wooden ball during its rotational drive.

[0059] The images resulting from this visualization are processed and the control unit 10, which has determined, from the data relating to the rotation speed of the ball and the position of the cutting member 6, the linear speed of the wood strip 21 and the position of the leading end 22 of the strip, controls the cutting device 9 at times depending on the presence / absence of defects and their positions relative to the leading end 22 to obtain strip sections which are in turn directed towards one of the evacuation outlets of the installation according to their length relative to a set length and the presence or absence of defects.

[0060] Thus, the process includes, after the cutting operation, a step of diverting the strip section to allow, at the level of said first outlet 13, an evacuation of a strip section 231 having a defect and a length less than the set length; at the level of the second outlet 14, an evaluation of a strip section 232 free of defect and of a length less than the set length and; at the level of the third outlet 15, an evacuation of a strip section free of defect and of a length equal to the set length.

[0061] At least the sections of strip free from defects and of equal length to the specified length are taken back to cut into boards 24.

[0062] Such an installation 1 makes it possible to reduce the occurrence of musculoskeletal disorders in operators and allows an increase in production rate, in particular of wooden boards.

[0063]

Claims

Demands

1. Installation (1) for cutting logs (20), said installation (1) comprising at least one uncoiler (2), said uncoiler (2) comprising a frame (3) with a receiving location (4) for a log (20), a motor-driven rotation device (5) for rotating the log (20) within said location (4) about an axis (XX') of rotation corresponding to a longitudinal axis of the log (20) for rotation of the log (20) about itself, and at least one cutting member (6) mounted movable in the direction of the axis (XX') of rotation to allow, as the log (20) is rotated, the production at the output of the uncoiler (2) of a strip (21) of cuttable wood with a longitudinal axis (YY') orthogonal to the axis (XX') of rotation. the wooden ball (20),characterized in that the installation (1) comprises a visualization system (7) for detecting defects (25) in the wood, a system (8) for determining a parameter representative of the speed of movement of the wood strip (21), a device (9) for cutting the wood strip (21) in a direction parallel to the axis (XX') of rotation of the log (20), i.e., transverse to the longitudinal axis (YY') of the strip (21) to form at least one strip section and a control unit (10), in that the visualization system (231, 232,233) is arranged upstream of the device (9) for cutting the wood strip (21) into strip sections taken with respect to the direction of movement of the wood strip (21), and in that the control unit (10) is configured to control the device (9) for cutting the wood strip (21) into strip sections based at least on the data provided by the visualization system (7) for detecting wood defects and the system (8) for determining a parameter representative of the speed of movement of the wood strip (21).

2. Installation (1) according to claim 1, characterized in that it comprises a path (11) for the movement of the strip (21) of wood coming from the uncoiler (2), and in that the device (9) for cutting the strip (21) of wood into strip sections is disposed on said path (11).

3. Installation (1) according to any one of claims 1 or 2, characterized in that the visualization system (7) for detecting wood defects comprises at least one image-taking device (71), such as a camera, directed towards the location (4) for receiving the log (20) of wood and / or towards the path (11) of the strip (21) coming from the uncoiler (2) to visualize an area (72) called the image-taking area.

4. Installation (1) according to any one of claims 1 to 3, characterized in that the system (8) for determining a parameter representative of the speed of movement of the wood strip (21) comprises at least a first device (81) for measuring the speed of rotation of the log (20) of wood and a second device (82) for determining the position of the cutting element (6) and in that the control unit (10) is configured to, as a function of the data of the first and second devices (81, 82), determine by calculation the so-called linear speed of the strip (21) at the exit of the uncoiler (2) and consequently the position of one (22) of the so-called driving end of the strip (21) opposite to that connected to the log (20) of wood.

5. Installation (1) according to claim 4, characterized in that the control unit (10) is configured to control the device (9) for cutting the wood strip (21) into strip sections as a function at least of the data provided by the display system (7) and of the position of the driving end (22) of the strip (21) itself as a function of the linear speed of the strip (21).

6. Installation (1) according to any one of claims 4 or 5, characterized in that the control unit (10) is configured to, when a wood defect is detected by the visualization system (7), determine the position of the defect relative to the position of the leading end (22) of the strip (21) and control the strip cutting device (9) as a function at least of the position of the defect relative to the position of the leading end (22) of the strip (21) to obtain a strip section whose length is a function at least of the position of the defect relative to the position of the leading end (22) of the strip (21).

7. Installation (1) according to any one of claims 1 to 6, characterized in that the installation (1) is equipped with a memory (12) for storing at least one setpoint length of a strip segment.

8. Installation (1) according to claim 7, characterized in that the installation (1) comprises at least a first (13), a second (14) and a third (15) strip section discharge outlet to permit, at said first outlet (13) discharge of a strip section (231) having a defect and a length less than the set length, at said second outlet (14) discharge of a strip section (232) free of defect and of a length less than the set length and, at said third outlet (15) discharge of a strip section (233) free of defect and of a length equal to the set length (233).

9. Installation (1) according to claim 8, characterized in that the installation (1) comprises a switch (16) disposed between the wood cutting device (9) and said first, second and third exits (13, 14, 15).

10. Installation (1) according to claim 9 taken in combination with claim 2, characterized in that the switch (16) is disposed at the end of the path (11) of the band (21) coming from the unwinder (2) and forms a movable part of said path (11) which can be selectively positioned opposite one of the first, second and third exits (13, 14, 15).

11. Installation (1) according to any one of claims 1 to 10, characterized in that it comprises an additional cutting device (17) for cutting at least some (233) of the sections (231, 232, 233) of strip into planks (24).

12. Assembly comprising at least one log (20) of wood and an installation (1) for cutting said log (20) of wood, characterized in that the installation (1) conforms to any one of claims 1 to 11.

13. A method for cutting a log (20) of wood, particularly for the manufacture of boards (24), using a log (1) cutting installation (20) of wood comprising at least one uncoiler (2), said uncoiler (2) comprising a frame (3) with a receiving location (4) for a log (20) of wood, a device (5) for driving the log (20) of wood in rotation within said location (4) about an axis (XX') of rotation corresponding to a so-called longitudinal axis of the log (20) of wood for rotation of the log (20) of wood about itself and at

14.

15. less a cutting member (6) mounted movable in the direction of the axis (XX') of rotation and configured to allow, as the log (20) of wood is rotated, the production at the output of the uncoiler (2) of a strip (21) of cuttable wood, said strip (21) having at the output of the uncoiler (2) a longitudinal axis orthogonal to the axis (XX') of rotation of the log (20) of wood, characterized in that the installation (1) for cutting the log (20) of wood conforming to any one of claims 1 to 11, the method includes a step of visualizing the log (20) of wood and / or the strip (21) resulting from the uncoiling in order to detect wood defects,a step of determining a parameter representative of the speed of movement of the wooden strip (21) and a step of transversely cutting the strip (21) into at least one strip section according to the data provided during the steps of visualization and determination of a parameter representative of the speed of movement of the wooden strip (21). A method for cutting a log (20) of wood according to claim 13, characterized in that the step of determining a parameter representative of the speed of movement of the strip (21) of wood comprises a step of measuring the rotational speed of the log (20) and determining the position of the cutting element (6), a step of determining, from said data, the so-called linear speed of the strip (21) at the exit of the uncoiler (2) and consequently the position of the driving end (22) of the strip (21) opposite to that connected to the log (20) to allow, when a wood defect has been visualized during the visualization step, the determination of the position of said defect relative to the driving end (22) of the strip, and in that, during the step of cutting the strip (21),The strip (21) is cut according to at least the data provided during the visualization step and the position of the leading end (22) of the strip (21) itself, which is a function of the linear speed of the strip (21), the position of the strip (21) cutting device (9) being predetermined and known. A method for cutting a log (20) according to claim 14, characterized in that, a set length of strip section being stored, the method comprises, during the strip cutting step (21), cutting either a strip section (231) having a defect and of a length less than the length of

16. instruction, either of a section of strip (232) free from defects and of a length less than the instruction length, or of a section of strip (233) free from defects and of a length equal to the instruction length. A method for cutting a log (20) according to claim 15, characterized in that the installation (1) comprises at least a first (13), a second (14) and a third (15) strip section discharge outlet and a diverter (16) disposed between the wood strip cutting device (9) and said first (13), second (14) and third (15) discharge outlets, the method comprises, after the operation of cutting the strip into a strip section, a strip section diverting step to allow, at said first outlet (13), discharge of a strip section (231) having a defect and a length less than the set length, at said second outlet (14), discharge of a strip section (232) free from defects and of a length less than the set length, and, at said third outlet (15),a section of strip (233) free from defects and of equal length to the specified length.

Images