Abstract:
A board unscrambler for sorting a plurality of boards comprises a frame having an entrance and an exit. The frame comprises a U-shaped accumulator near the entrance and an upwardly substantially longitudinal slope connecting the U-shaped accumulator portion to the exit. The board unscrambler further comprises a powered conveyor which substantially adopts the shape of the frame, comprising driving chains and a plurality of spaced apart catches mounted on the driving chains for mating with and displacing the boards along the frame from the U-shaped accumulator portion toward the exit. Accordingly, the board unscrambler features accumulation capability, thereby increasing efficiency and regulating performance.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. patent provisional application 62/146,741 filed Apr. 13, 2015, the specification of which is hereby incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     (a) Field 
     The subject matter disclosed generally relates to systems for sorting or unscrambling boards and to methods of operating the same. 
     (b) Related Prior Art 
     Lumber manufacturing nowadays has become increasingly competitive to a point where its operations must be automated as much as possible for economic viability of the manufacturing process. 
     In automating various lumber processing machinery, it is often necessary to receive an agglomerated supply of scrambled elongated boards, having longer dimensions extending somewhat in the same general direction, and turn the longitudinal boards to a uniform parallel attitude while singulating them, individually, or in small groups, in adjacency or at discrete intervals for delivery to other devices, machines, machineries or components for further processing. Machines accomplishing this function are commonly known in the lumber industry as board unscramblers, board sorters, unscrambling devices or unscramblers. 
     There exists on the market a plurality of apparatuses for unscrambling boards. 
     U.S. Pat. No. 6,401,906, to Franz et al., describes a S-shaped board unscrambler for lumber processing. The efficiency of such an apparatus is not optimal. 
     According to another example, and referring now to PRIOR ART  FIG. 1 , there is shown a V-shaped board unscrambler for lumber processing. The efficiency of such an apparatus is not optimal. 
     There is therefore a need for improved board unscramblers for sorting a plurality of boards that overcome the prior art drawbacks and that allows for improved efficiency of the sorting process of the boards. 
     SUMMARY 
     According to an embodiment, there is disclosed a board unscrambler adapted for unscrambling boards comprising: a frame having an entrance and an exit for the boards, the frame comprising: a U-shaped accumulator portion in which the boards accumulate after the entrance; and an upward slope portion between the U-shaped accumulator portion and the exit; and a powered conveyor comprising catches for carrying forward the boards along the frame from the U-shaped accumulator portion through the upward slope portion toward the exit; wherein boards which are not directly or indirectly carried forward by the catches will fall back in the U-shaped accumulator portion thereby resulting in an unscrambling of the boards which are carried forward. 
     According to an aspect, the upward slope portion is substantially longitudinal. 
     According to an aspect, the upward slope portion comprises a curved portion. 
     According to an aspect, the upward slope portion is a direct and immediate continuation of the U-shaped accumulator portion. 
     According to an aspect, the upward slope portion forms part of and is integrated with the U-shaped accumulator portion. 
     According to an aspect, the catches have a substantial longitudinal shape having a longitudinal direction which is substantially parallel to the boards. 
     According to an aspect, the powered conveyor comprises driving chains to which the catches are mounted wherein the driving chains are parallel to each other and in a direction which is perpendicular to the entrance and the exit wherein the entrance and the exit extends laterally and are substantially parallel to each other. 
     According to an aspect, the catches mounted on respective ones of the driving chains are horizontally aligned. 
     According to an aspect, the catches have a substantial longitudinal shape having a longitudinal direction which is substantially parallel to the boards and the catches are mounted across more two or more driving chains. 
     According to an aspect, the powered conveyor further comprises a drive shaft and geared wheels which are spaced apart on the drive shaft, and wherein the driving chains ride on the geared wheels. 
     According to an aspect, the frame comprises a rail along which the driving chains travel. 
     According to an aspect, the board unscrambler further comprises a motor driving the powered conveyor. 
     According to an aspect, the motor driving the powered conveyor is connected to the drive shaft thereby driving the geared wheels. 
     According to an aspect, the U-shaped accumulator portion has a radius of curvature R of about between 0.1 meters and 3 meters. 
     According to an aspect, the entrance is at a first elevation, and the exit is at a second elevation, and wherein the second elevation is greater than the first elevation. 
     According to an aspect, the upward slope portion defines an angle of about between 40° and 80° relative to the horizontal. 
     According to an aspect, comprising sensors for monitoring boards on the powered conveyor. 
     According to an embodiment, there is disclosed a method of unscrambling boards comprising: providing boards perpendicularly to a forward direction of movement of the boards; accumulating boards in a U-shaped accumulator; and a conveyor catching at least some boards for carrying them forward on an upward slope still perpendicularly to a forward direction of movement of the boards; wherein boards which are not directly or indirectly carried forward by the catches will fall back from the upward slope or remain in the U-shaped accumulator thereby resulting in an unscrambling of the boards which are carried forward. 
     According to an embodiment, there is disclosed a board unscrambler adapted for unscrambling boards comprising: a U-shaped accumulator in which the boards accumulate after entering the board unscrambler; an upward slope after the U-shaped accumulator; and a powered conveyor comprising catches for carrying forward the boards from the U-shaped accumulator through the upward slope; wherein boards which are not directly or indirectly carried forward by the catches will fall back from the upward slope or remain in the U-shaped accumulator thereby resulting in an unscrambling of the boards which are carried forward. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the present disclosure will become apparent from the following detailed description, taken in combination with the appended drawings, in which: 
         FIG. 1  is a picture showing a V-shaped board unscrambler in accordance with the PRIOR ART; 
         FIG. 2  is a picture showing a board unscrambler in accordance with an embodiment; 
         FIGS. 3-11  are pictures showing the board unscrambler of  FIG. 2  in operation; 
         FIG. 12  is a picture showing the board unscrambler of  FIG. 2  according to another perspective; 
         FIG. 13  is a picture showing the board unscrambler of  FIG. 2  according to another perspective also showing part of an upstream conveyor; and 
         FIGS. 14-15  are pictures showing the motor and chain assembly driving the board unscrambler according to an embodiment. 
     
    
    
     It will be noted that throughout the appended drawings, like features are identified by like reference numerals. 
     DETAILED DESCRIPTION 
     In embodiments there are disclosed board unscramblers, also commonly known as board sorters, unscrambling devices or unscramblers, for sorting or unscrambling a plurality of boards and methods of operating the same. 
     It has to be noted that the embodiments, geometrical configurations, materials mentioned and/or dimensions shown in the figures or described in the present description are preferred embodiments only, given for exemplification purposes only. 
     Throughout the present document, expressions such as “conveying”, “transferring”, “displacing”, “wood board”, “lumber”, “mill”, etc., used herein should not be taken as to limit the scope of the present invention and include all other kinds of objects or fields with which the present invention could be used and may be useful. 
     Moreover, in the context of the present invention, the expressions “system”, “assembly”, “unit”, “device” and any other equivalent expression and/or compound words thereof known in the art will be used interchangeably. Furthermore, the same applies for any other mutually equivalent expressions, such as “wood board”, “board”, “lumber”, “elongated piece of lumber”, “log”, “plank” and the like, “sorting”, “unscrambling”, “arranging”, “straightening” and the like, as well as “segment”, “portion” and “section”, for example, as also apparent to a person skilled in the art. Furthermore, and also in the context of the present description, the expressions “align”, “orientate”, “place” and “space” may also be used interchangeably, as well as “finger”, “stop wedge” and “stopper”, or even “second” and “subsequent”, as also apparent to a person skilled in the art. 
     Referring now to the drawings, and more particularly to  FIG. 2 , there is shown a board unscrambler  10  for sorting a plurality of boards  12 . The board unscrambler  10  includes a frame  14  which defines an entrance  16  and an exit  18 . According to an embodiment, the entrance  16  is at a first elevation, and the exit  18  is at a second elevation, and wherein the second elevation is greater than the first elevation. 
     The frame  14  of the board unscrambler  10  includes a U-shaped accumulator portion  20  near and below the entrance  16  and an upward slope portion  22  after and generally above the U-shaped accumulator portion  20  towards the exit  18 . According to an embodiment, the upward slope portion  22  is substantially longitudinal or at least comprises a substantially longitudinal portion. According to another embodiment, the upward slope portion  22  comprises a curved portion. 
     The board unscrambler  10  further includes a conveyor  24  (aka a powered conveyor) which substantially adopts the shape of the frame  14 . The conveyor  24  comprises driving chains  26  for conveying boards  12  about the frame  14  in a travel or forward direction that is substantially perpendicular to the boards  12 . A plurality of regularly spaced apart stop wedges  28  are mounted on the driving chains  26 . The term “wedges” here is used in the sense that they are used to create a separation between boards or groups of boards while the conveyor  24  drives the wedges forward on the conveyor  24 . While the present description discusses stop wedges  28 , it is understood that other types of wedges (such as catches, hooks, gaps, lips, chocks, chucks, stops, blocks, etc.) capable of carrying forward the boards  12  could also be incorporated in the present design. 
     According to an embodiment the catches (stop wedges  28 ) have a substantial longitudinal shape having a longitudinal direction which is substantially parallel to the boards. Furthermore, the catches comprise a top longitudinal side and a bottom longitudinal side opposite the top longitudinal side, wherein the top longitudinal side interfaces with the boards  12  and carries the boards  12  forward. 
     When the plurality of boards  12  are received on the conveyor  24 , within the U-shaped accumulator portion  20 , at least one board  12  from the plurality of boards  12  that are in contact with the conveyor  24  engages with one stop wedge  28  from the plurality of regularly spaced apart stop wedges  28  and is displaced on the slope portion  22  towards the exit  18 . The purpose of the U-shaped accumulator portion  20  after or near the entrance  16  is to receive and to accumulate a plurality of boards  12  that are falling from an upstream conveyor  42  passed the entrance  16  in a way such as to allow only the boards  12  that are following the conveyor surface  29  of the conveyor  24  (that are on the conveyor surface  29  of the conveyor  24 ) in the U-shaped accumulator portion  20  to be displaced by the plurality of regularly spaced apart stop wedges  28  towards the slope portion  22 . 
     The frame  14  includes a base  56  for supporting the board unscrambler  10  on the ground surface. 
     As shown in  FIG. 2 , the conveyor  24  comprises the driving chains  26 , specifically a plurality of parallel driving chains  26   a ,  26   b ,  26   c ,  26   d ,  26   e  allowing the plurality of boards  12  to be sorted and driving the boards  12  over the conveyor surface  29 . Stop wedges  28  are mounted on the driving chains  26  of the same length, at similar position, resulting in having stop wedges  28  at the same elevation for each driving chains  26   a ,  26   b ,  26   c ,  26   d ,  26   e . The stop wedges  28  can be mounted on a single driving chain  26  or across multiple driving chains  26  depending on their chosen length. The outcome is a board unscrambler  10  able to keep the boards  12  horizontal when displacing the boards  12 . 
     Now also referring to  FIGS. 14-15 , the plurality of driving chains  26  (driving chains  26   a ,  26   b ,  26   c ,  26   d ,  26   e  shown in  FIG. 2 ) are powered by a driving mechanism  58 . The driving mechanism  58  comprises a motor  60 , a first drive shaft  30  about the entrance  16  and a second drive shaft  32  distant from the first drive shaft  30  and about the exit  18 . The first and second drive shafts  30 ,  32  are in driving arrangement/engagement with the motor  60  through shaft-driving chains  62 . The first drive shaft  30  defines a first axis  34  on which are mounted a plurality of first geared wheels  36  while the second drive shaft  32  defines second axis  38  on which are mounted a plurality of second geared wheels  40 . The plurality of first geared wheels  36  and the plurality of second geared wheels  40  respectively rotate about the first and second axis  34 ,  38  for meshing with the plurality of driving chains  26   a ,  26   b ,  26   c ,  26   d ,  26   e.    
     Also referring to  FIGS. 13-14 , the driving mechanism  58  may comprise additional drive shafts (not shown and/or with no reference number) defining axes (not shown and/or with no reference number) for receiving additional geared wheels (not shown and/or with no reference number). These additional geared wheels have the purpose of driving or guiding the driving chains  26  along a return path away from the conveyor surface  29 . 
     Location of the first drive shaft  30  may vary. Feeding of the U-shaped accumulator portion  20  with boards  12  may be performed with aid of the driving chains  26  or with aid of a conveyor mechanism of the upstream conveyor  42  and/or gravity effect.  FIG. 13  shows an embodiment wherein the boards  12  are pushed down in the U-shaped accumulator portion  20  by the stop wedges  28  as they reach the entrance  16  of the board unscrambler  10 . 
     Each one of the plurality of driving chains  26   a ,  26   b ,  26   c ,  26   d ,  26   e  includes a plurality of regularly spaced apart stop wedges  28  to cooperate with (to transport individually or in groups as it will be described below) the plurality of boards  12  from the U-shaped accumulator portion  20  towards the slope portion  22  (from the entrance  16  towards the exit  18  of the frame  14 ). The plurality of driving chains  26  are powered by the driving mechanism  58  such as to provide the plurality of regularly spaced apart stop wedges  28  (the five spaced apart stop wedges  28   a ,  28   b ,  28   c ,  28   d ,  28   e  of the five parallel driving chains  26   a ,  26   b ,  26   c ,  26   d ,  26   e , as shown in  FIG. 2 ) to travel at the same level about the frame  14  in a way to allow the plurality of boards  12  to travel from the U-shaped accumulator portion  20  entrance  16  towards the exit  18  in a predefined orientation (substantially perpendicularly to the conveyor surface  29  and parallel, according to their longitudinal orientation, to the exit  18  of the frame  14 ); that is, the stop wedges  28   a ,  28   b ,  28   c ,  28   d ,  28   e  mounted on respective ones of the driving chains  26   a ,  26   b ,  26   c ,  26   d ,  26   e  are horizontally aligned. 
     Each one of the plurality of regularly spaced apart stop wedges  28  may include a projection outwardly extending from the respective ones of the plurality of driving chains  26   a ,  26   b ,  26   c ,  26   d ,  26   e  (parallel driving chains  26 ). The projection may be integrally formed with the plurality of driving chains  26  or may be connected driving chains  26  using known connection techniques. 
     The distance between two regularly spaced apart stop wedges  28  on a driving chain  26  may substantially be the width of one, two, three, four or more board(s)  12  such as to allow the one or more board(s)  12  to be pushed by the plurality of regularly spaced apart stop wedges  28  that are travelling along with the conveyor  24 . A proposed configuration is based on the dimensions of the boards  12 , dimensions of the U-shaped accumulator portion  20  and power of the driving motor for instance. 
     The driving chains  26  are mounted in such a way to adopt at least part of the shape of the frame  14 , preferably a displacement path defined substantially from at least the bottom of the U-shaped accumulator portion  20  to the exit  18  of the frame  14 , moreover preferably from the entrance  16  of the U-shaped accumulator portion  20  to the exit  18 . Commonly known techniques may be used for the driving chains  26  to marry at least sections of the frame  14 , such as driving channels or stop wedges  28  having a portion sliding over part of the frame  14 . Shown on  FIG. 13 , the driving chains  26  may naturally adopt the shape of a portion of the frame  14  when sliding over the frame  14 , with the married portion of the frame  14  acting as a rail guiding the driving chains  26  and preventing the chains from “derailing” as lateral forces may be applied on the driving chains  26  by the boards  12 . The shape of unguided portions of the driving chains  26  may be determined by natural tension and/or may depend on additional wheels guiding the driving chains  26  according to a desired path, for instance passing under the conveyor surface  29 . Since the first drive shaft  30  and the second drive shaft  32  are linked by shaft-driving chains  62  and rotate synchronously, the length of the driving chains  26  between the entrance and the exit on the conveyor surface  29  stays mostly constant and the driving chain  26  is kept pressed on the rail at the bottom of the U-shaped accumulator portion  20 . 
     Referring particularly to  FIG. 3 , the U-shaped accumulator portion  20  typically defines a radius of curvature R of about between 0.1 meters and 3 meters so as to receive and to accumulate a sufficient number of boards  12  that needs to be sorted. According to another embodiment, the radius of curvature R is between 0.5 meters and 2.5 meters. According to another embodiment, the radius of curvature R is between 1.0 meter and 2.0 meters. According to another embodiment, the radius of curvature R is between 1.25 meters and 1.75 meters. 
     The U-shaped accumulator portion  20  is for receiving a plurality of boards  12  that are coming from a previous operation. The U-shaped accumulator portion  20  is therefore for receiving a plurality of boards  12  that are coming from the upstream conveyor  42 . A driving chain  44  that drives the upstream conveyor  42  about its frame  46  is powered by a driving mechanism  58  (which can be distinct from the driving mechanism  58 ). The driving mechanism  58  includes a motor  60  and a third drive shaft  48  about the entrance  16  that defines a third axis  50 . The third axis  50  is distant from the first axis  34 . The third drive shaft  48  receives a plurality of third geared wheels  52  to rotate about that third axis  50  for meshing with the driving chain  44 , thereby driving the upstream conveyor  42  about the frame  46 . As best shown in  FIG. 3 , the frame  46  further includes a plurality of guides  54  for guiding the plurality of boards  12  that are travelling from the upstream conveyor  42  to fall within the U-shaped accumulator portion  20  located below the level of the upstream conveyor  42 . 
       FIG. 15  illustrates an embodiment wherein the same driving mechanism  58  is used to drive the board unscrambler  10  and a downstream conveyor  64  receiving boards  12  once they exit the board unscrambler  10 . 
     Returning to  FIG. 3 , the slope portion  22  defines an angle θ of typically about between 40° and 80° relative to the ground surface (not shown). The purpose of the slope portion  22  that has a predetermined angle θ relative to the ground surface is to compel the boards  12  not mating with the stop wedges  28  (or with another board  12  that cooperates with the stop wedges  28 ) to fall back by gravity effect in the U-shaped accumulator portion  20 . According to another embodiment, angle θ is between 45° and 75° relative to the ground surface. According to another embodiment, angle θ is between 50° and 70° relative to the ground surface. According to another embodiment, angle θ is between 55° and 65° relative to the ground surface. According to another embodiment, angle θ is between 70° and 75° relative to the ground surface. According to another embodiment, angle θ is between 75° and 80° relative to the ground surface. 
       FIGS. 3-11  show the board unscrambler  10  in operation.  FIG. 3  shows that the plurality of boards  12  to be sorted are laying on the upstream conveyor  42 ; the stack of boards  12  coming from a previous process. It is to be mentioned that the upstream conveyor  42  may be continuously transporting the plurality of boards  12  towards the U-shaped accumulator portion  20 , or may be punctually or periodically transporting boards  12  towards the entrance  16 , and as a result in the U-shaped accumulator portion  20 . 
       FIGS. 4-5  show that the upstream conveyor  42  is in operation mode transporting the boards  12  towards the entrance  16  of the board unscrambler  10 . The boards  12  (shown in a stack) will follow the plurality of guides  54  extending from the frame  46  and fall, helped by gravity, within the U-shaped accumulator portion  20  following the conveyor surface  29  as they pass the entrance  16 . 
       FIG. 6  shows that some of the boards  12  that are laying on the conveyor surface  29  within the U-shaped accumulator portion  20  will enter in direct contact with the stop wedges  28 , and thereby be displaced by the plurality of regularly spaced apart stop wedges  28 , while some will be indirectly pushed by the other boards  12  that are cooperating with the stop wedges  28 . 
       FIG. 7  shows when some boards  12  have been transported from the U-shaped accumulator portion  20  to the slope portion  22 , about to actually reach the exit  18  of the board unscrambler  10 . These boards  12  will be guided towards another station to be subject to a subsequent processing step.  FIGS. 7-11  further show that boards  100  that are not directly or indirectly mating and/or cooperating with the stop wedges  28  will fall (by gravity effect caused by the angle θ) back within the U-shaped accumulator portion  20 . Accordingly, they become available to be driven up the longitudinal slope portion  22  upon directly or indirectly mating the stop wedges  28  at a pass of subsequent “upstream” stop wedges  28 . 
     It is to be noted that the board unscrambler  10  may further include sensors (not shown) as an aid in performing monitoring operations such as counting the number of boards  12  passing through the board unscrambler  10 , registering the width and/or length of the boards  12  passing through the board unscrambler  10 , registering the color or other physical characteristic of the boards  12  passing through the board unscrambler  10 , and/or the like. A feedback signal can then be sent to the upstream conveyor  42  in order to control its speed. If the board unscrambler  10  can accommodate more boards, the speed of the upstream conveyor will be increased while, on the other hand, if the board unscrambler  10  is already full, the speed of the upstream converter  42  will be reduced. 
     It is to be noted that the frame  14 , the U-shaped accumulator portion  20 , the slope portion  22 , the conveyor  24 , the driving chains  26 , the regularly spaced apart stop wedges  28 , and the driving mechanism  58  may adopt alternative configurations (sizes, angles, relative parameters) while respecting the objectives herein described. 
     Specifically, the U-shaped accumulator portion  20  is adapted to receive a plurality of boards  12  and at the same time to provide the board unscrambler  10  with an increased efficiency. That increased efficiency includes having more boards  12  that can be sorted in a given period compared to the prior art apparatuses and providing improved and/or regulated performance with an upstream conveyor  42  punctually or periodically transporting boards  12 . 
     While preferred embodiments have been described above and illustrated in the accompanying drawings, it will be evident to those skilled in the art that modifications may be made without departing from this disclosure. Such modifications are considered as possible variants comprised in the scope of the disclosure.