Patent Publication Number: US-11376757-B2

Title: Lumber loading system and method for simultaneous loading and longitudinal displacement of successive lumber pieces using same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of the filing date of International Application No. PCT/CA2018/050286, filed Mar. 9, 2018, which application claims priority under 35USC § 119(e) of US provisional patent application 62/469,882, which was filed on Mar. 10, 2017, the specifications of which are hereby incorporated by reference. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to the field of lumber loading and trimming. More particularly it relates to a lumber loading system for transferring lumbers between a first carrier assembly and a second carrier assembly while positioning the lumber longitudinally and to a method of operation of the system for performing the same. 
     BACKGROUND 
     In the field of lumber production, loading systems are commonly used to individually transfer lumber pieces between a first carrier assembly and a second carrier assembly. Typically, upon loading of the lumber pieces on the second carrier assembly by such a loading system, each one of the lumber pieces are loaded between cleats (or lugs, or cleat sets) of the second carrier assembly and can be subsequently processed individually in the production line. 
     For example and without being limitative, loading systems are generally used to transfer the lumber pieces on a carrier assembly (or conveyor), following the planing of the lumber pieces, to subsequently perform trimming and/or sorting thereof. Typically, in order to perform the trimming and/or sorting, each lumber piece is individually marked and is subsequently loaded by the loading system onto the carrier assembly. Once it is loaded on the carrier assembly, each lumber piece corresponding to a specific cleat (or lug, or cleat set) is identified (for example by reading the previously generated mark or tracking); the trimming position is determined according to optimization parameters based on characteristics of the lumber piece (e.g. curvature data, modulus of elasticity data, etc.); the lumber piece is moved longitudinally on the carrier assembly (i.e. the lumber piece is moved along its length as it is conveyed transversally to its length on the carrier assembly) to be positioned properly for trimming; the trimming is performed as the lumber piece is moved by the carrier assembly along the production line; and the lumber piece is subsequently sorted for subsequent operations. 
     It will be understood that, each operation of the above described sequence of operations for performing trimming and/or sorting requires space along the carrier assembly, thereby resulting in substantial longitudinal space being required for the system performing these operations as the lumber pieces are conveyed. For example, see  FIG. 1  showing a prior art system for performing trimming and sorting of lumber pieces. Moreover, some operations which are intrinsically linked (such as the longitudinal positioning of the lumber pieces and the trimming thereof) are performed sequentially, thereby resulting in increased production time and a possible loss of precision due to the transfer of the lumber pieces between the performance of the operations. 
     In view of the above, there is a need for an improved loading system and method of operation thereof, which would be able to overcome or at least minimize some of the above-discussed prior art concerns. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a first general aspect, there is provided a lumber loading system for transferring lumber pieces conveyed in a conveying direction defined by a conveying axis. The lumber loading system comprises a driving shaft rotating about a longitudinal axis; at least one lumber piece grasping assembly operatively connected to the driving shaft and rotating about the longitudinal axis along with the driving shaft; and a longitudinal positioning system connected to the at least one lumber piece grasping assembly. The at least one lumber piece grasping assembly is displaceable along the longitudinal axis and is operative to initially grasp a section of a corresponding one of the lumber pieces with the corresponding one of the lumber pieces extending longitudinally substantially parallel to the longitudinal axis, temporarily maintain the section of the lumber piece and subsequently release the lumber piece. The longitudinal positioning system moves each one of the at least one lumber piece grasping assembly independently along the longitudinal axis, during rotation thereof about the longitudinal axis. 
     In an embodiment, the lumber loading system further comprises guiding shafts rotating along with the rotation of the driving shaft and extending along the longitudinal axis. The guiding shafts support each one of the at least one lumber piece grasping assembly slidably mounted thereon. Each one of the at least one lumber piece grasping assembly is movable longitudinally along corresponding ones of the guiding shafts. 
     In an embodiment, the at least one lumber piece grasping assembly each include a carriage slidably engaged with the corresponding ones of the guiding shafts. The carriage comprises at least one lumber supporting member engaging a first surface of a corresponding lumber piece and at least one lumber grasping member selectively engageable to a second surface of the lumber piece, opposed to the first surface thereof. 
     In an embodiment, the longitudinal positioning system comprises a linear actuator connected to the carriage of each one of the at least one lumber piece grasping assembly and selectively driving the corresponding carriage along the longitudinal axis. 
     In an embodiment, the lumber loading system comprises a plurality of lumber piece grasping assemblies angularly spaced apart around the driving shaft. 
     In an embodiment, the longitudinal axis is substantially perpendicular to the conveying axis. 
     In an embodiment, the lumber loading system further comprises a trimming assembly configured and positioned to trim at least one end of the lumber pieces transferred by the lumber loading system. The trimming assembly comprises at least one trimmer having a trimming blade operatively connected to a motor driving the trimming blade in rotation. 
     In an embodiment, the trimming assembly includes a first trimming assembly and a second trimming assembly. The first trimming assembly is positioned to trim a first end of the lumber pieces transferred by the lumber loading system at a first angular position about the longitudinal axis and the second trimming assembly is positioned to trim a second end of the lumber pieces transferred by the lumber loading system at a second angular position about the longitudinal axis, angularly distal from the first angular position. 
     In an embodiment, the longitudinal positioning system is configured to position each one of the at least one lumber piece grasping assembly in a first longitudinal position along the longitudinal axis, prior to a corresponding one of the lumber pieces maintained thereby reaching the angular position of the first trimming assembly, and to position each one of the at least one lumber piece grasping assembly in a second longitudinal position along the longitudinal axis, prior to the corresponding one of the lumber pieces maintained thereby reaching the angular position of the second trimming assembly. 
     In an embodiment, the lumber loading system further comprises at least one supplemental supporting assembly operative to grasp, temporarily maintain and subsequently release a supplemental section of the lumber pieces along the longitudinal axis, during a least a portion of the transfer of the lumber pieces. 
     In an embodiment, each one of the at least one supplemental supporting assembly comprises at least one support wheel mounted to the driving shaft and having a supplemental lumber engaging surface engageable to a first surface of the lumber pieces and at least one supplemental lumber grasping member selectively engageable to a second surface of the lumber pieces, opposed to the first surface thereof. 
     In accordance with another general aspect, there is also provided a method for simultaneous loading and longitudinal displacement of successive lumber pieces. For each one of the successive lumber pieces, the method comprising the steps of: conveying the lumber piece in a conveying direction defined by a conveying axis; grasping the lumber piece using a lumber piece grasping assembly with the lumber piece extending longitudinally substantially parallel to a longitudinal axis substantially perpendicular to the conveying axis; maintaining the lumber piece using the lumber piece grasping assembly during rotation of the lumber piece grasping assembly about the longitudinal axis and simultaneously displacing the lumber piece grasping assembly longitudinally along the longitudinal axis, to position the lumber piece at a predetermined longitudinal position thereof; and releasing the lumber piece from the lumber piece grasping assembly. 
     In an embodiment, the method further comprises the step of determining an optimized longitudinal position of the lumber piece and wherein the predetermined longitudinal position is the optimized longitudinal position. 
     In an embodiment, the step of grasping the lumber piece using a lumber piece grasping assembly includes pivoting at least one pivoting finger in an engaged configuration to engage a surface of the lumber piece and press a portion of the lumber piece against a lumber supporting surface of the lumber supporting member of the lumber piece grasping assembly. 
     In an embodiment, the method further comprises the step of trimming at least one end of the lumber piece. The step of trimming at least one end of the lumber piece is performed after the step of displacing the lumber piece grasping assembly longitudinally and before the step of releasing the lumber piece from the lumber piece grasping assembly. 
     In an embodiment, the method further comprises the steps of initially trimming a first end of the lumber piece and subsequently trimming a second end of the lumber piece. The steps of trimming a first end of the lumber piece and trimming a second end of the lumber piece are performed at different angular positions of the lumber piece grasping assembly about the longitudinal axis. 
     In an embodiment, the steps of displacing the lumber piece grasping assembly longitudinally along the longitudinal axis comprises performing a first longitudinal displacement of the lumber piece grasping assembly prior to the step of trimming a first end of the lumber piece and performing a second longitudinal displacement of the lumber piece grasping assembly following the step of trimming the first end of the lumber piece and prior to the step of trimming the second end of the lumber piece. 
     In an embodiment, the method further comprising the steps of: grasping at least one additional section of the lumber piece being transferred, using at least one supplemental supporting assembly; temporarily maintaining the at least one additional section of the lumber piece using the at least one supplemental supporting assembly; and releasing the lumber piece from the at least one supplemental supporting assembly. 
     In an embodiment, the method further comprises the steps of: grasping a first additional section of the lumber piece being transferred, using a first subset of the at least one supplemental supporting assembly, following the step of performing the first longitudinal displacement of the lumber piece grasping assembly and prior to the step of trimming the first end of the lumber piece; releasing the lumber piece from the first subset of the at least one supplemental supporting assembly following the step of trimming the first end of the lumber piece and prior to the step of performing the second longitudinal displacement of the lumber piece grasping assembly; grasping a second additional section of the lumber piece being transferred, using a second subset of the at least one supplemental supporting assembly, following the step of performing the second longitudinal displacement of the lumber piece grasping assembly and prior to the step of trimming the second end of the lumber piece; and releasing the lumber piece from the at least one supplemental supporting assembly following the step of trimming the second end of the lumber piece. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects, advantages and features will become more apparent upon reading the following non-restrictive description of embodiments thereof, given for the purpose of exemplification only, with reference to the accompanying drawings in which: 
         FIG. 1  is a side schematic representation of a prior art system for performing trimming of lumber pieces, in accordance with an embodiment. 
         FIG. 2  is an isometric view of a lumber loading system, in accordance with an embodiment. 
         FIG. 3  is an isometric view of the lumber loading system of  FIG. 2 , shown with a top cover removed to allow a better viewing of the components thereof. 
         FIG. 4  is a side elevation view of the lumber loading system of  FIG. 3 . 
         FIG. 5  is an isometric view of the rotating shaft of the lumber loading system of  FIG. 2 , with the components of the lumber loading system mounted thereto, and shown in isolation. 
         FIG. 6  is an enlarged view of a section the rotating shaft of the lumber loading system of  FIG. 5  with the components of the lumber loading system mounted thereto, shown in isolation, showing in more details a longitudinal positioning assembly. 
         FIG. 7  is an enlarged view of another section of the rotating shaft of the lumber loading system of  FIG. 5  with the components of the lumber loading system mounted thereto, shown in isolation, showing in more details the lumber piece grasping assemblies. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, the same numerical references refer to similar elements. The embodiments, geometrical configurations, materials mentioned and/or dimensions shown in the figures or described in the present description are embodiments only, given solely for exemplification purposes. 
     Although the embodiments of the lumber loading system and corresponding parts thereof consist of certain geometrical configurations as explained and illustrated herein, not all of these components and geometries are essential and thus should not be taken in their restrictive sense. It is to be understood, as also apparent to a person skilled in the art, that other suitable components and cooperation thereinbetween, as well as other suitable geometrical configurations, may be used for the lumber loading system, as will be briefly explained herein and as can be easily inferred herefrom by a person skilled in the art. Moreover, it will be appreciated that positional descriptions such as “above”, “below”, “left”, “right” and the like should, unless otherwise indicated, be taken in the context of the figures and should not be considered limiting. 
     Moreover, although the embodiments as illustrated in the accompanying drawings comprise particular steps of a method, not all of these steps are essential and thus should not be taken in their restrictive sense. It is to be understood, as also apparent to a person skilled in the art, that other suitable sequence of operations may be used for the method, as will be briefly explained herein and as can be easily inferred herefrom, by a person skilled in the art, without departing from the scope of the invention. 
     Referring generally to  FIGS. 2 to 7 , in accordance with one embodiment, there is provided a lumber loading system  20 . The lumber loading system  20  is configured to cooperate with a first carrier assembly  12  positioned upstream of the lumber loading system  20  along a production line (not shown) and operative to convey successive lumber pieces  16  towards the lumber loading system  20  and at least a second carrier assembly (not shown) positioned downstream of the lumber loading system  20  along the production line and operative to receive the lumber pieces  16  from the lumber loading system  20  and subsequently convey the lumber pieces  16  away from the lumber loading system  20 . The lumber pieces  16  are elongated workpieces conveyed in a conveying direction (i.e. conveyed in a direction defined by a lumber conveying axis X). For example and without being limitative, the lumber pieces  16  can be elongated planed lumber, such as wood planks or the like. Hence, one skilled in the art will understand that the lumber loading system  20  can be part of a production line which extends along the lumber conveying axis X thereof, substantially perpendicular to the length of the lumber pieces  16  and where the lumber pieces  16  are transversally conveyed along the lumber conveying axis X of the production line. In other words, the lumber pieces  16  are conveyed along the lumber conveying axis X of the production line (and extend longitudinally substantially transversally to the lumber conveying axis X), as they are conveyed along the first carrier assembly  12 , the lumber loading system  20 , and the second carrier assembly (not shown). 
     The lumber loading system  20  is configured to transfer the lumber pieces  16  from the first carrier assembly  12  to the second carrier assembly (not shown) and perform longitudinal movement (i.e. longitudinal positioning) of each one of the lumber pieces  16 , as they are being transferred (i.e. simultaneously with the transfer movement thereof). In order to perform the longitudinal displacement of the lumber pieces  16  during the transfer thereof, the lumber loading system  20  includes a driving shaft  21  rotatable about a longitudinal axis Y and at least one longitudinally movable lumber piece grasping assembly  22  (i.e. at least one lumber piece grasping assembly  22  movable along the longitudinal axis Y) operatively connected to the driving shaft  21 . The lumber piece grasping assembly  22  is operative to grasp a section of a transferred lumber piece  16 , with the lumber piece  16  extending longitudinally substantially parallel to the longitudinal axis Y, temporarily retain the section of the transferred lumber piece  16  as the lumber piece grasping assembly  22  is rotated about the longitudinal axis Y and moved longitudinally along the longitudinal axis Y, and subsequently release the transferred lumber piece  16 . 
     In the embodiment shown, a plurality of angularly spaced-apart lumber piece grasping assemblies  22  are operatively connected to the driving shaft  21 , each lumber piece grasping assembly  22  transferring a corresponding lumber piece  16 . Hence, in operation, each lumber piece grasping assembly  22 , grasps, maintains, longitudinally positions and releases a corresponding lumber piece  16 , such that multiple lumber pieces  16  can be simultaneously transferred and longitudinally positioned by the lumber loading system  20 . Each lumber piece grasping assembly  22  is independent, such that each lumber piece  16  temporarily maintained by a corresponding lumber piece grasping assembly  22  can be independently moved longitudinally to reach a desired longitudinal position thereof, as it is being transferred. 
     In the embodiment shown, each lumber piece grasping assembly  22  includes a carriage  30  slidably mounted relative to the driving shaft  21  (and relative to the longitudinal axis Y). More particularly, in the embodiment shown, the lumber loading system  20  includes guiding shafts  24  rotatable along with the rotation of the driving shaft  21  and extending along the longitudinal axis Y, with the carriage  30  being slidably mounted to the guiding shafts  24 , to be freely movable therealong. Hence, each carriage  30  is slidable with regard to the corresponding guiding shafts  24 , in order to the positioned according to the longitudinal axis Y, as will be described in more details below. 
     One skilled in the art will understand that, in alternative embodiments (not shown), other assemblies could be provided to allow the movement of the carriage  30  of each lumber piece grasping assembly, along the longitudinal axis Y. For example and without being limitative, in an embodiment (not shown) the lumber loading system  20  could include a supporting base mounted to the driving shaft  21  and rotating therewith, with the supporting base including guiding shafts extending along the longitudinal axis Y, for each corresponding carriage  30  operatively connected to the driving shaft  21  and each carriage  30  including sliders slidably engaged with the corresponding guiding shafts. 
     To grasp, temporarily retain and subsequently release the lumber pieces  16 , the carriage  30  of each lumber piece grasping assembly  22  further includes at least one lumber supporting member  34  engaging a first surface of a corresponding lumber piece  16  and at least one lumber grasping member  38  selectively engageable to a second surface of the lumber piece  16 , opposed to the first surface thereof. 
     In the embodiment shown in  FIGS. 2 to 7 , each carriage  30  has two lumber supporting members  34  spaced apart along the longitudinal axis Y. Each lumber supporting member  34  has a lumber supporting surface  35  defined at an outer edge thereof, with a projecting tooth  36  extending substantially radially therefrom and engaging the first surface of the lumber piece  16 . The carriage  30  further includes a lumber grasping member  38 , embodied by two pivoting fingers  39  pivotable between an engaged configuration and a disengaged configuration. The pivoting fingers  39  are each positioned proximate to a corresponding lumber supporting member  34 . 
     In the engaged configuration, each pivoting finger  39  is pivoted to engage the second surface of the lumber piece  16 , thereby sandwiching a portion of the lumber piece  16  between a section of the lumber supporting surface  35  of the lumber supporting member  34  and the corresponding pivoting finger  39  (i.e. pressing the portion of the lumber piece  16  against the section of the lumber supporting surface  35 ) and firmly maintaining the lumber piece  16  therebetween. In an embodiment, in the engaged configuration, each pivoting finger  39  presses the portion of the lumber piece  16  against at least portion of the projecting tooth  36  of the lumber supporting surface  35  of the lumber supporting member  34 . 
     In the disengaged configuration, each pivoting finger  39  is pivoted away from the second surface of the lumber piece  16  (i.e. away from the lumber supporting surface  35  of the corresponding lumber supporting member  34 ) and is disengaged therefrom. Therefore, when the pivoting fingers  39  are pivoted from the engaged configuration to the disengaged configuration, the grip is released on the lumber piece  16 . In an embodiment, the pivoting fingers  39  are each connected to a rotary actuator  40  pivoting the corresponding pivoting finger  39  between the engaged configuration and the disengaged configuration and vice-versa. In the embodiment shown, the rotary actuators  40  are pneumatic actuators. One skilled in the art will however understand that, in alternative embodiments (not shown), the rotary actuators  40  could be of another type such as, for example an electric actuator or the like. 
     One skilled in the art will understand that, in alternative embodiments, the lumber piece grasping assembly  22  operative to firmly maintain the lumber piece  16  being transferred, could differ from the embodiment shown. For example and without being limitative, more or less than the two spaced apart lumber supporting members  34  could be provided and/or the lumber supporting members  34  could be free of projecting tooth  36 . Moreover, more or less than the two pivoting fingers  39  could be provided and/or a component different from a pivoting finger could be used for the lumber grasping member  38 . Furthermore, an assembly different from the above described guiding shafts and sliders could be provided to allow movement of the carriages  30  relative to the driving shaft  21 , along the longitudinal axis Y. For example and without being limitative, a longitudinally displaceable clamp or other types of longitudinally displaceable engaging member could be used. 
     Referring to more particularly to  FIGS. 5 and 7 , to move the lumber piece  16  longitudinally (i.e. along the longitudinal axis Y) as it is being transferred by the lumber loading system  20 , the lumber loading system  20  further includes a longitudinal positioning assembly  50  moving each lumber piece grasping assembly  22  longitudinally along the longitudinal axis Y. For example and without being limitative, in  FIG. 7 , one of the carriage  30  of a lumber piece grasping assembly  22  is shown in a longitudinal position different from the longitudinal position of the other carriages  30 . As can be seen in  FIG. 7 , the carriage  30  moves relative to the guiding shafts  24  as it is being displaced longitudinally. 
     In the embodiment shown, the longitudinal positioning assembly  50  includes a linear actuator  59  connected to each carriage  30  by a connecting shaft  57  and linearly displacing the corresponding carriage  30  along the longitudinal axis Y. For example and without being limitative, in an embodiment, each linear actuator  59  includes a servomotor which allows a precise control of the linear position of the corresponding carriage  30 . One skilled in the art will understand that, several types of linear actuators (or motors) could be used as part of the servomotor, such as, without being limitative, a mechanical actuator, a hydraulic actuator, a pneumatic actuator, a piezoelectric actuator, or the like. The linear actuator  59  performs longitudinal positioning of each carriage  30  during rotation of the driving shaft  21 , thereby resulting in longitudinal movement of the corresponding lumber piece  16  grasped by the corresponding lumber piece grasping assembly  22 , during its transfer. 
     One skilled in the art will again understand that, in alternative embodiments (not shown), a longitudinal positioning assembly  50  different than the embodiment shown could be used for performing the longitudinal displacement of the lumber piece grasping assemblies  22 . 
     For example and without being limitative, in an alternative embodiment (not shown), the longitudinal positioning assembly  50  could include a positioning cam and a positioning cam follower mounted to each carriage  30  of a lumber piece grasping assembly  22  and engageable with a corresponding positioning cam and a return cam and a return cam follower mounted to each carriage  30  and engageable to the corresponding return cam for returning the carriage to an initial carriage position, following the longitudinal positioning thereof. In such an embodiment, during operation, the positioning cam could be actuated to drive the cam follower and displace the carriage  30  along the longitudinal axis Y. Following the longitudinal positioning of the carriage  30  by the combination of the positioning cam driving the positioning cam follower, the carriage  30  could be driven back to an initial longitudinal position through engagement of the return cam follower with the return cam. An actuator could be provided to move the positioning cams in order to induce movement to the corresponding carriages  30 , through the positioning cam follower, and position the carriages  30  in the desired longitudinal positions. 
     In the embodiment shown, the longitudinal positioning assembly  50  can move the lumber piece grasping assemblies  22  in a first direction along the longitudinal axis Y and a second direction opposed to the first direction also along the longitudinal axis Y. For example and without being limitative, in an embodiment, the longitudinal positioning assembly  50  can move the lumber piece grasping assemblies  22  of at least about 6 inches in the first direction and at least about 6 inches in the second direction, thereby providing a longitudinal travel distance of at least about 12 inches. 
     In an embodiment, the lumber loading system  20  carries each transferred lumber pieces  16  between a grasping position and a release position along at least about 90° and less than about 270° and, in a particular embodiment, less than about 180°. 
     In the embodiment shown, the lumber loading system further includes at least one supplemental supporting assembly  80  for engaging and supporting the corresponding lumber pieces  16 , along supplemental sections thereof, during the transfer of the lumber pieces  16 . In the embodiment shown, the supplemental supporting assembly  80  includes at least one support wheel  82  mounted to the driving shaft  21  and operating as supplemental lumber supporting members  84 . The support wheel  82  has a supplemental lumber engaging surface  85  and supplemental projecting teeth  86  extending substantially radially therefrom and substantially angularly aligned with the projecting teeth  36  of the lumber piece grasping assemblies  22 . The supplemental supporting assembly  80  also includes supplemental lumber grasping members  88 , embodied by supplemental pivoting fingers  89  pivotable between an engaged configuration and a disengaged configuration (similar to the above described engaged configuration and a disengaged configuration of the pivoting fingers  39  of the lumber grasping member  38  of the lumber piece grasping assembly  22 ). The supplemental pivoting fingers  89  are each connected to a rotary actuator  87  pivoting the corresponding supplemental pivoting finger  89  between the engaged configuration and the disengaged configuration and vice-versa. In the embodiment shown, the rotary actuators  87  are pneumatic actuators. One skilled in the art will however understand that, in alternative embodiments (not shown), the rotary actuators  87  could be of another type such as, for example an electric actuator or the like. 
     As can be seen in the Figures, the lumber grasping members  88  are substantially angularly aligned with the lumber grasping members  38  of the lumber piece grasping assemblies  22 , to clasp the corresponding section of one of the lumber piece between the corresponding supplemental pivoting finger  89  (or angularly aligned set of pivoting fingers  89 ) and at least a section of the corresponding one of the supplemental teeth  86 . 
     In the embodiment shown, the at least one support wheel  82  of each one of the at least one supplemental supporting assembly  80  is fixedly mounted to the driving shaft  21  (i.e. is not displaceable along the longitudinal axis Y) and has sections (i.e. a corresponding supplemental tooth  86  and lumber grasping members  88 ) angularly aligned with each corresponding lumber piece grasping assembly  22 . Hence, the supplemental grasping members  88  thereof are operative to grasp and retain the corresponding sections of the lumber piece  16  engaged by each supplemental supporting assembly  80 , once the lumber piece  16  has been properly positioned longitudinally by the corresponding lumber piece grasping assembly  22 . In other words, the at least one supplemental supporting assembly  80  can grasp the corresponding section of the lumber piece  16  at a later time than the corresponding lumber piece grasping assembly  22 , once the lumber piece grasping assembly  22  has been positioned longitudinally, such that the lumber piece  16  has reached the desired longitudinal position. 
     As will be described in more details below, in an embodiment, the supplemental supporting assembly  80  allow a section of a corresponding lumber piece  16  to be maintained, for example during and/or following the trimming thereof (i.e. until the lumber piece  16  is released by the corresponding lumber piece grasping assembly  22 ). This allows a better trimming as the lumber piece is maintained in a section proximal to where the lumber piece is trimmed and prevents a trimmed section (a section release from the lumber piece following the trimming) to fall and thereby potentially interfere with the proper functioning of the apparatus. 
     In an embodiment, the at least one supplemental supporting assembly  80  could include a first subset  80   a  of supplemental supporting assemblies  80  and a second subset  80   b  of supplemental supporting assemblies  80 , with the first subset of supplemental supporting assemblies  80   a  and the second subset of supplemental supporting assemblies  80   b  engaging separate sections of a lumber piece  16 . In an embodiment, the supplemental lumber grasping members  88  of the first subset of supplemental supporting assemblies  80   a  and the second subset of supplemental supporting assemblies  80   b  could engage the lumber piece  16  at different angular position around the longitudinal axis, for example in order to match the trimming performed at the corresponding angular position. 
     One skilled in the art will understand that, in alternative embodiments (not shown), the at least one supplemental supporting assembly  80  could include lumber supporting members  84  spaced apart along the longitudinal axis Y with independent freely movable sections (i.e. independent portions including a supplemental lumber engaging surface  85  and a supplemental lumber grasping member  88 , for example embodied by at least one supplemental pivoting finger  89  pivotable between an engaged configuration and a disengaged configuration) substantially angularly aligned with a corresponding carriage  30  around the driving shaft  21 , rather than the support wheel  82  of the embodiment shown. In an embodiment (not shown), each one of the independent sections can be operatively connected to the driving shaft  21 , to be freely longitudinally movable therealong. Hence, in such embodiments, the supplemental lumber grasping member  88  can be operative to grasp and retain the section of the lumber piece substantially simultaneously to the corresponding lumber piece grasping assembly  22 , such that the independent freely movable sections of the supplemental supporting assembly  80  are independently moved along with the corresponding lumber piece  16  being moved longitudinally, as a result of the corresponding lumber piece grasping assembly  22  being driven longitudinally by the longitudinal positioning assembly  50 . In other words, in such embodiments, the independent freely movable sections of the supplemental supporting assembly  80  are not actuated but rather simply movable with regard to the longitudinal axis Y, along with the corresponding lumber piece  16  it temporarily grasps. 
     In an embodiment, the lumber loading system  20  includes an electronic control system (not shown) operatively connected to the actuators  40  of the lumber grasping member  38  and/or the linear actuators  59  of the longitudinal positioning assembly  50  and/or the actuators  87  of the supplemental grasping members  88  of the supplemental supporting assembly, such that the operations of the components of the lumber piece grasping assembly  22 , the longitudinal positioning assembly  50  and/or the supplemental supporting assembly  80 , for grasping, maintaining, longitudinally moving and releasing the transferred lumber piece  16 , are synchronized. Hence, each transferred lumber piece  16  is moved longitudinally as sections of the transferred lumber piece  16  are being maintained and supported by the lumber supporting member  34  and the lumber grasping member  38 . In an embodiment, the electronic control system can receive data relative to each lumber piece  16  in order to perform the specific longitudinal displacement for each one of the lumber piece  16  being transferred as will be described in more details below. 
     For example and without being limitative, in an embodiment, a scanning assembly can scan the lumber pieces  16  conveyed on the first carrier assembly  12  to examine the lumber pieces  16  and generate optimization parameters thereof related to the longitudinal positioning of each lumber pieces  16 , with the electronic control system controlling the components of the lumber piece grasping assembly  22 , the longitudinal positioning assembly  50  and/or the supplemental supporting assembly  80  according to the received optimization parameters. 
     Referring to  FIGS. 2 to 7 , in the embodiment shown, the lumber loading system  20  further includes a trimming assembly  60  operative to perform trimming of at least one end of the lumber pieces  16  transferred and longitudinally positioned by the lumber loading system  20 . The trimming assembly  60  includes at least one trimmer  62  having a trimming blade  64  operatively connected to a motor  66  driving the trimming blade  64  in rotation. In such an operation, each lumber piece  16  being transferred by the lumber loading system  20  can consequently be adequately positioned longitudinally (through longitudinal movement of the corresponding lumber piece grasping assembly  22 ) for the trimming blade  64  to engage the lumber piece  16  at the desired position and therefore trim the lumber piece  16  according to optimization parameters specific to the lumber piece  16 . 
     In an embodiment, the trimming assembly  60  can include a plurality of trimmers  62  spaced apart along the longitudinal axis Y and/or a plurality of trimming blades  64  spaced apart along the longitudinal axis Y and operatively connected to the motor  66  of a trimmer  62  for driving the trimming blades  64  in rotation. Hence, the trimming assembly  60  can include multiple trimmers  62  or multiple trimming blades  64  positioned along the longitudinal axis Y and engageable to a section of the lumber pieces  16  for performing trimming thereof. Therefore, in such an embodiment a smaller longitudinal displacement of the lumber piece  16  by the longitudinal positioning assembly  50  can be required to position the lumber piece  16  adequately, relative to a trimming blade  64 , to perform the trimming thereof. In other words, in such an embodiment, the lumber piece  16  is only required to be positioned longitudinally relative to the trimming blade  64  closest to the section of the lumber piece  16  that is to be trimmed. 
     For example and without being limitative, in an embodiment, where the longitudinal positioning assembly  50  can move the lumber piece grasping assemblies  22  of about 6 inches in the first direction and about 6 inches in the second direction, thereby providing a longitudinal travel distance of about 12 inches, the multiple trimmers  62  or multiple trimming blades  64  positioned along the longitudinal axis Y can be spaced apart of a distance of about 12 inches along the longitudinal axis Y. One skilled in the art will understand that, in alternative embodiments where the longitudinal positioning assembly  50  can move the lumber piece grasping assemblies  22  of a different distance, the distance between the multiple trimmers  62  or multiple trimming blades  64  along the longitudinal axis Y can be adjusted to substantially match the longitudinal travel distance provided by the longitudinal positioning assembly  50 . 
     In an embodiment, each one of the multiple trimmers  62  or multiple trimming blades  64  positioned along the longitudinal axis Y can be selectively and independently movable transversally to the longitudinal axis Y (for example in a substantially downward/upward movement), such that the trimmer  62  or trimming blade  64  closest to the section of the lumber piece  16  that is to be trimmed can be moved toward the lumber piece  16  to perform the trimming. For example and without being limitative, each one of the multiple trimmers  62  or multiple trimming blades  64  can be connected to a linear trimmer actuator  68  activable to selectively move the corresponding trimmer  62  or trimming blade  64  in the substantially downward/upward movement to proceed to the trimming of the lumber piece  16 . In an embodiment, the linear trimmer actuator  68  can be a pneumatic actuator. One skilled in the art will understand that, in alternative embodiments, the linear trimmer actuator  68  can be of another type, such as, a mechanical actuator, a hydraulic actuator, a piezoelectric actuator, or the like. 
     In the embodiment shown, the lumber loading system  20  includes a first trimming assembly  60   a  and a second trimming assembly  60   b , each trimming the lumber pieces  16  at a different angular position, as the lumber pieces  16  are being transferred. In the embodiment shown, the first trimming assembly  60   a  includes a single trimmer  62  and is positioned upstream of the second trimming assembly  60   b , along the lumber conveying axis X. The second trimming assembly  60   b  includes multiple trimmers  62  substantially angularly aligned along the longitudinal axis Y. The combination of the first trimming assembly  60   a  and the second trimming assembly  60   b  allows each lumber piece  16  transferred by the lumber loading system  20  to be trimmed twice, with the lumber piece  16  being moved longitudinally between the first trimming assembly  60   a  and the second trimming assembly  60   b.    
     In view of the above, it will be understood that the lumber piece grasping assemblies  22  of the lumber loading system  20  can each be independently moved longitudinally by the longitudinal positioning assembly  50  prior to reaching the angular position where the first trimming assembly  60   a  engages the piece of lumber  16  and be again moved longitudinally by the longitudinal positioning assembly  50  after moving past the angular position where the first trimming assembly  60   a  engages the piece of lumber  16  and before reaching the angular position where the second trimming assembly  60   b  engages the piece of lumber  16 . Such a combination allows production of lumber pieces  16  of many different lengths, without being limited to the distance between two of the multiple trimmers  62  or trimming blades  64  of a single trimming assembly. 
     In an embodiment the electronic control system (not shown) can also be operatively connected to the trimming assembly  60  (i.e. operatively connected to the trimmers  62 , the motor  66  associated to a trimmer blade  64  and/or the trimmer actuator(s)  68  for selectively moving the trimmers  62  trimming blades  64  transversally to the longitudinal axis Y) and therefore allow synchronization of the operations of the trimming assembly  60  with the operations of the components of the lumber piece grasping assembly  22 , the longitudinal positioning assembly  50  and/or the supplemental supporting assembly  80 , for grasping, maintaining, longitudinally moving, trimming and releasing the transferred lumber piece  16 . 
     One skilled in the art will understand that, in an alternative embodiment, the lumber loading system  20  can be free of trimming assembly  60 . For example and without being limitative, in an embodiment (not shown), the trimming assembly  60  can be provided along the second carrier assembly (not shown) onto which the lumber pieces  16  are loaded in the optimized longitudinal position, given the longitudinal movement thereof provided by the lumber loading system  20  loading the lumber pieces  16  onto the second carrier assembly. 
     In view of the above, the lumber loading system  20  is configured to allow the lumber pieces  16  to be positioned longitudinally during transfer thereof between components of a production line (e.g. between the first carrier assembly  12  and the second carrier assembly (not shown)). Therefore, in operation, the above described lumber loading system  20  provides a solution that minimizes the space along a production line for performing multiple tasks by performing the longitudinal positioning of the lumber pieces  16  (and in an embodiment the trimming of the lumber pieces  16 ) during the transfer performed by the lumber loading system  20 . Hence, in an embodiment, the longitudinal positioning (and in an embodiment the trimming) of the lumber pieces  16  does not interfere or negatively impact on the speed of operation of the lumber loading system  20 , the driving shaft  21  of the lumber loading system  20  being allowed to rotate continuously to transfer the corresponding lumber piece  16  from the first carrier assembly  12  to the second carrier assembly. 
     The lumber loading system  20  having been described above, a sequence of operation of the lumber loading system (i.e. a method for simultaneous loading and longitudinal displacement of lumber pieces) will now be described in more details below. 
     In operation, the lumber pieces  16  are successively in a conveying direction defined by a lumber conveying axis X. The lumber pieces  16  are conveyed transversally on the first carrier assembly  12 , towards the lumber loading system  20 . During the conveying of the lumber pieces  16  (or previous manutention thereof) each lumber piece  16  is examined to generate optimization parameters thereof. Using the optimization parameters, an optimized longitudinal position of the lumber piece  16  is determined (or calculated). For example and without being limitative, the optimized longitudinal position can correspond to the longitudinal position best suited to perform an optimized trimming of at least one end of the lumber piece  16 . 
     When each successive lumber piece  16  reaches the lumber loading system  20 , in an embodiment, the lumber piece  16  is momentarily held against a stopper (not shown) until the lumber loading system  20  is ready to grasp the lumber piece  16 . When the lumber loading system  20  is ready to grasp one of the successive lumber pieces  16 , the stopper is retracted and the lumber piece  16  is moved towards a corresponding lumber piece grasping assembly  22 . The lumber piece grasping assembly  22  grasps a section of the lumber piece  16  and maintains the section of the lumber piece  16  in a firm grip, with the lumber piece  16  extending longitudinally substantially parallel to the longitudinal axis Y. The rotation of the driving shaft  21  subsequently rotates the lumber piece grasping assembly  22  and the transferred lumber piece  16  held by the lumber piece grasping assembly  22 , about the longitudinal axis Y. 
     In an embodiment, in order to perform the step of grasping the lumber piece  16 , the piece grasping assembly  22  pivots at least one pivoting finger  39  in an engaged configuration to engage a surface of the lumber piece  16  and thereby sandwich a portion of the lumber piece  16  between a lumber supporting surface  35  of the lumber supporting member  34  of the piece grasping assembly  22  and the at least one pivoting finger  39  (i.e. press a portion of the lumber piece  16  against the lumber supporting surface  35  of the lumber supporting member  34  of the piece grasping assembly  22 ), to firmly maintain the section of the lumber piece  16  therebetween. 
     The method further includes the step of moving the lumber piece grasping assembly  22  longitudinally, to position the lumber piece  16  at the optimized longitudinal position thereof, while the lumber piece  16  is maintained by the lumber piece grasping assembly and the lumber piece grasping assembly is rotated about the longitudinal axis Y. In other words, during the transfer of the lumber piece  16  (i.e. during the rotation of the lumber piece grasping assembly  22  retaining the lumber piece  16 ) about the longitudinal axis Y, the corresponding lumber piece grasping assembly  22  is moved longitudinally (i.e. moved along the longitudinal axis Y of the driving shaft  21 ) to position the lumber piece  16  in the previously determined optimized longitudinal position thereof. Hence, the lumber piece  16  is moved longitudinally as it is held firmly by the lumber piece grasping assembly  22 , as a result of the longitudinal movement of the lumber piece grasping assembly  22 . 
     In an embodiment, the method includes the further step of trimming at least one end of the lumber piece  16 , during the transfer of the lumber piece  16 . (i.e. during the rotation of the lumber piece grasping assembly  22  retaining the lumber piece  16 ). Hence, during the transfer of the lumber piece  16 , at least one end of the lumber piece  16  is trimmed by a trimming assembly  60 . The step of trimming the end of the lumber piece  16  is performed subsequently to the lumber piece being positioned longitudinally, therefore allowing the lumber piece  16  to be trimmed according to the optimized parameters for longitudinal positioning thereof. Once again, in such an embodiment the end of the lumber piece  16  is trimmed as the lumber piece  16  is held firmly by the lumber piece grasping assembly  22  (i.e. as the lumber piece  16  is loaded by the lumber loading system  20  between the first carrier assembly  12  and the second carrier assembly (not shown)). 
     In an embodiment, the step of trimming at least one end of the lumber piece  16  includes the step of initially trimming a first end of the lumber piece  16  and subsequently trimming a second end of the lumber piece  16 . The steps of trimming a first end of the lumber piece  16  and trimming a second end of the lumber piece  16  are performed at different angular position of the lumber piece grasping assembly  22  about the longitudinal axis Y. 
     In an embodiment, the steps of moving the lumber piece grasping assembly  22  longitudinally while the lumber piece  16  is maintained by the lumber piece grasping assembly and the lumber piece grasping assembly is rotated about the longitudinal axis Y includes performing a first longitudinal displacement of the lumber piece grasping assembly  22  prior to trimming a first end of the lumber piece  16  and performing a second longitudinal displacement of the lumber piece grasping assembly  22  following the trimming of the first end of the lumber piece  16  and prior to trimming the second end of the lumber piece  16 . 
     In an embodiment, the method includes the further step of grasping at least one additional section of the lumber piece being transferred, using at least one supplemental supporting assembly  80  grasping a section of the lumber piece  16  and maintaining the lumber piece  16  in a firm grip. The rotation of the driving shaft  21  once again rotates the at least one supplemental supporting assembly  80  and the transferred lumber piece  16  held by the lumber piece grasping assembly  22 , and the supplemental supporting assembly  80  about the longitudinal axis Y. 
     In an embodiment, where the step of trimming at least one end of the lumber piece  16  includes the step of initially trimming a first end of the lumber piece  16  and subsequently trimming a second end of the lumber piece  16 , the at least one supplemental supporting assembly  80  can include a first subset  80   a  of supplemental supporting assemblies  80  and a second subset  80   b  of supplemental supporting assemblies  80 . In such an embodiment, the method can include the steps of grasping a first additional section of the lumber piece  16  being transferred, using the first subset  80   a  of supplemental supporting assemblies  80 , prior to trimming a first end of the lumber piece  16  (and following the first longitudinal displacement of the lumber piece grasping assembly  22 ); releasing the first additional section of the lumber piece being transferred prior to the second longitudinal displacement of the lumber piece grasping assembly  22 ; and grasping at least a second additional section of the lumber piece  16  being transferred, using the second subset  80   b  of supplemental supporting assemblies  80 , prior to trimming a second end of the lumber piece  16  (and following the second longitudinal displacement of the lumber piece grasping assembly  22 ). 
     The method finally includes the step of releasing the lumber piece  16  onto the second carrier assembly (not shown). In other words, the lumber piece  16  is subsequently released by the lumber piece grasping assembly  22  (and the supplemental supporting assemblies  80  if such assemblies are used to maintain supplemental sections of the lumber piece  16 ) onto the second carrier assembly (not shown) and is conveyed transversally on the second carrier assembly (not shown) away from the lumber loading system  20 . 
     In an embodiment, the above-described steps are coordinated by a control system (not shown) based on the optimization parameters for each of the lumber pieces. One skilled in the art will understand that, in an alternative embodiment, other mechanism or method could be used to coordinate the operation of the components to perform the above-described steps. 
     Several alternative embodiments and examples have been described and illustrated herein. The embodiments of the invention described above are intended to be exemplary only. A person skilled in the art would appreciate the features of the individual embodiments, and the possible combinations and variations of the components. A person skilled in the art would further appreciate that any of the embodiments could be provided in any combination with the other embodiments disclosed herein. It is understood that the invention may be embodied in other specific forms without departing from the central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein. Accordingly, while specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the scope of the invention as defined in the appended claims.