Abstract:
Provided is a positioning fence for use in lumber sawmills that facilitates automated positioning of lumber for cutting and a method of positioning lumber for cutting. A continuous moving track loop has a plurality of paddles laterally positionable across the width of the track. Electromagnets are used to control the position of the paddles and, thus, the position of lumber being transported by the paddles. Also provided are uses of the positioning fence to position lumber for cutting.

Description:
[0001]    This application claims priority to U.S. Provisional Patent Application Ser. Nos. 61/180,988, filed 26 May 2009, and 61/302,564, filed 9 Feb. 2010, the complete disclosures of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTIONS 
       [0002]    The inventions relate to positioning fences for lumber or timber in sawmills or planermills and methods of using the positioning fences. 
       BACKGROUND OF THE INVENTIONS 
       [0003]    In sawmills, various lumber or timber handling machinery is provided to cut and shape the lumber or timber into saleable wood products. One of the required operations in a mill, after sawing or forming to the desired cross section, is end trimming individual boards or timbers to a specified length. 
         [0004]    To cut the material to length, a typical arrangement of transport equipment has a conveyor that has a lug chain table to transport the lumber pieces to length cutting saws. The lumber pieces are carried along the conveyor in equidistantly spaced succession based on the lug spacing of the lug chains. The conveyor has a set of lateral alignment rollers. The lateral alignment rollers form a roller bed system placed at right angles to the lug chain, which operate to urge one end of the lumber material toward a stop or fence, also referred to as a paddle. In this arrangement, each successive piece of lumber is spaced from the other in the direction of travel along the lumber conveyor by the lugs of the lug chain and one of the ends of the lumber is laterally aligned to the stop or fence. 
         [0005]    The piece to be cut to length is positioned for contact with a saw or series of saws. In the configuration of sawmill conveyor equipment just described, the saws are stationary relative to the conveyor and the board is laterally positioned on the conveyor relative to the saw blade. A positioning fence, which one end of the lumber piece abuts against, controls the lateral position of the lumber piece on the feed conveyor. Numerous prior art arrangements for adjustable positioning fences for use with such a feed conveyor arrangement have been proposed in the past. For example a step positioning fence is disclosed in the published Canadian Patent application 2,241,481 of Wight et al. The stepped positioning fence of Wight has a plurality of rigid elevated faces, or steps that extend longitudinally along a side of the fence in an adjacent stepped array of differing offset spacing. The fence is oriented to present one of the steps for contact with the lumber piece to align the lumber end to the corresponding offset of that step. The lumber is urged into contact with the fence by the lateral alignment rollers resulting in alignment of the lumber end to the fence step offset. The stepped fence provides fixed incremental ending settings and a positioning mechanism to ensure the board is presented with a step suitable to obtain the desired or intended lateral translation of the board piece. 
         [0006]    Another flexible trimmer position fence is disclosed in Canadian Patent 2,191,390 to Jackson, which discloses a board positioning fence comprised of a plurality of adjustable fence elements each staged one after the other in the downstream direction of travel of the lumber to be positioned. The lumber is urged against the positioning fence by lateral alignment or ending rollers. The ending rollers urge the lumber laterally across the feed conveyor into contact with the successive fence elements of the board positioning fence. When the desired lateral positioning of the board is achieved, lift skids are engaged to remove the lumber from contact with the lateral urging end rollers. This arrangement has multiple flexible fence elements, which are adjusted to allow the board to be ended to the desired positioning or ending location. Once the board has been displaced laterally to the desired position offset, skids are engaged that lift the positioned lumber piece away from the ending rollers. 
         [0007]    Another arrangement to provide board lumber end positioning is disclosed in the Canadian patent 2,236,508 of Hannebauer et al. Hannebauer discloses a circulating paddle positioning fence with a flexible guide track. Actuators position the flexible guide track, which results in corresponding positioning of a paddle to a desired offset or ending position. 
         [0008]    And yet another positioning mechanism is disclosed in the published Canadian Patent application 2,345,872 of Jobin, for apparatus for positioning pieces of wood for precise cutting. Jobin discloses an adjustable barrier, which is provided with actuators to position the barrier to the desired offset location. Various forms of adjustable barriers are shown including ones which have a face that remains perpendicular to the board as well as providing for incline planes that have a set displacement selected by an actuator to achieve an ending or offset of the lumber laterally to the desired offset amount. 
         [0009]    A further positioning mechanism is disclosed in U.S. Pat. No. 7,419,047. This patent discloses a continuous moving track loop having a plurality of paddles laterally positionable across the width of the track. Complex mechanical brake mechanisms, positioning cams and reset cams are used to position the paddles. 
         [0010]    There is a need for a simplified board positioning mechanism that positions accurately, does not operate via cylinders, compressed air or hydraulics and is resistant to wear. 
       SUMMARY OF THE INVENTION 
       [0011]    The invention relates to an apparatus for positioning a lumber piece comprising:
       a continuous track loop;   a plurality of paddles spacedly disposed along the length of the continuous track loop, at least one paddle slideably mounted along a bearing way coupled to the track loop so that the paddle is laterally displaceable across a width of the track loop, and wherein the paddle comprises a lumber surface for contacting a surface of the lumber piece and stopping the lumber in a desired position perpendicular to a longitudinal direction of the track loop during use;   the at least one paddle having a locking mechanism constructed and arranged to lock the lateral position of the at least one paddle on the bearing way, the locking mechanism being biased in a closed position and being constructed such that when the locking mechanism is in a closed position the paddle is locked in position on the bearing way;   an actuator disposed at an angle across the width of the track, the actuator constructed and arranged such that when activated the locking mechanism is in an open position and the paddle is free to move along the length of the bearing way and when the actuator is deactivated the locking mechanism locks the position of the paddle on the bearing way; and   a paddle roller bank disposed at an angle across the width of the track, the paddle and paddle roller bank constructed and arranged so that as the track moves during operation and the locking mechanism is in an open position the paddle moves in the direction of the track and along the paddle roller bank which moves the paddle in a direction along the bearing way from a starting position to a desired position on the bearing way, and when the actuator is deactivated the locking mechanism goes to a closed position and the paddle is in a locked position on the bearing way and movement of the track pulls the paddle away from the paddle roller bank so that the paddle then moves only in the direction of the track.       
 
         [0017]    The invention also relates to an apparatus for positioning a lumber piece comprising:
       a continuous track loop;   a plurality of paddles spacedly disposed along the length of the continuous track loop, at least one paddle slideably mounted along a bearing way coupled to the track loop so that the paddle is laterally displaceable across a width of the track loop, and wherein the paddle comprises a lumber surface for contacting a surface of a lumber piece and stopping the lumber in a desired position perpendicular to a longitudinal direction of the track loop during use;   the at least one paddle having a locking mechanism constructed and arranged to lock the lateral position of the at least one paddle on the bearing way, the locking mechanism comprising a movable pin biased in a closed position where a first end of the pin is against the bearing way, the pin having a pad disposed at a second end of the pin, a first surface of the pad facing away from the pin and a second surface of the pad facing the pin;   an actuator magnet bank disposed at an angle across the width of the track, the actuator magnet bank constructed and arranged such that when activated the pad on the pin is attracted to the actuator magnet bank and the pin is moved into an open position where the first end of the pin is not against the bearing way and the paddle is free to move along the length of the bearing way and when the actuator magnet bank is deactivated the first end of the pin is against the bearing way to lock the position of the paddle on the bearing way; and   a paddle roller bank disposed at an angle across the width of the track, the paddle roller bank comprising a depression constructed to receive a portion of a roller ball, the paddle having a roller ball receiver containing a roller ball biased in a direction towards the depression, a portion of the roller ball disposed within the depression so that as the track moves during operation the paddle moves in the direction of the track and in the direction of the bearing way as the roller ball travels along a length of the paddle roller bank which moves the paddle from a starting position on the bearing way to a desired position on the bearing way, and when the locking mechanism is moved to a closed position, the paddle is locked, and movement of the track forces the ball to retract into roller ball receiver so that the roller ball leaves the depression and the paddle then moves only in the direction of the track.       
 
         [0023]    The invention further relates to an apparatus for positioning a lumber piece comprising:
       a continuous track loop;   a plurality of paddles spacedly disposed along the length of the continuous track loop, at least one paddle slideably mounted along a bearing way coupled to the track loop so that the paddle is laterally displaceable across a width of the track loop, and wherein the paddle comprises a lumber surface for contacting a surface of a lumber piece and stopping the lumber in a desired position perpendicular to a longitudinal direction of the track loop during use;   the at least one paddle having a locking mechanism constructed and arranged to lock the lateral position of the at least one paddle on the bearing way, the locking mechanism comprising a movable pin biased in a closed position, the pin having a first end that contacts the bearing way when in the closed position and a pad disposed at a second end of the pin;   an actuator magnet bank disposed at an angle across the width of the track, the actuator magnet bank constructed and arranged such that when activated the pad on the pin is attracted to the actuator magnet bank and the pin is moved into an open position where the first end of the pin does not contact the bearing way and the paddle is free to move along the length of the bearing way and when the actuator magnet bank is deactivated the first end of the pin contacts the bearing way to lock the position of the paddle on the bearing way; and   a paddle roller magnet bank disposed at an angle across the width of the track, the paddle having a surface that is magnetically attracted to the paddle roller magnet bank so that as the track moves during operation the surface of the paddle is magnetically bound to the paddle roller magnet bank and travels along the paddle roller magnet bank which moves the paddle moves from a starting position to a desired position on the bearing way, and when the pin is moved to a closed position, the paddle is locked, and movement of the track overtakes the magnetic force between the paddle roller magnet bank and the surface of the paddle so that the paddle then moves only in the direction of the track.       
 
         [0029]    The invention also relates to a method of positioning a lumber piece traveling on a conveyor comprising:
       a continuous track loop;   a plurality of paddles spacedly disposed along the length of the continuous track loop, at least one paddle slideably mounted along a bearing way coupled to the track loop so that the paddle is laterally displaceable across a width of the track loop, and wherein the paddle comprises a lumber surface for contacting a surface of the lumber piece and stopping the lumber in a desired position perpendicular to a longitudinal direction of the track loop;   the at least one paddle having a locking mechanism constructed and arranged to lock the lateral position of the at least one paddle on the bearing way, the locking mechanism being biased in a closed position and being constructed such that when the locking mechanism is in a closed position the paddle is locked in position on the bearing way;   an actuator disposed at an angle across the width of the track, the actuator constructed and arranged such that when activated the locking mechanism is in an open position and the paddle is free to move along the length of the bearing way and when the actuator is deactivated the locking mechanism locks the position of the paddle on the bearing way; and   a paddle roller bank disposed at an angle across the width of the track, the paddle and paddle roller bank constructed and arranged so that as the track moves during operation and the locking mechanism is in an open position the paddle moves in the direction of the track and along the paddle roller bank which moves the paddle in a direction along the bearing way from a starting position to a desired position on the bearing way, and when the actuator is deactivated the locking mechanism goes to a closed position and the paddle is in a locked position on the bearing way and movement of the track pulls the paddle away from the paddle roller track so that the paddle then moves only in the direction of the track, the method comprising:   transporting a piece of lumber with the lumber contacting the paddle;   moving the lumber in a direction perpendicular to the travel of the track until a desired position of the lumber is reached;   switching the locking mechanism to a closed position when the desired position of the lumber is reached which locks the paddle in place on the bearing way and stops further movement of the lumber in the direction perpendicular to the travel of the track;   separating the paddle from the paddle roller bank by continuing to move the track while the paddle is in a locked position on the bearing way so that the lumber only travels in the direction of the track; and   returning the paddle to a starting position.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0040]      FIG. 1  is a top view of an embodiment of the positioning fence; 
           [0041]      FIG. 2  is a side view of the positioning fence of  FIG. 1 ; 
           [0042]      FIG. 3  is a side view of a paddle, an actuator magnet bank, and a paddle roller magnet bank; 
           [0043]      FIG. 4  is a cut away view of a positioning fence; 
           [0044]      FIG. 5  is a top view of a positioning fence; 
           [0045]      FIG. 6  is a side view of a positioning fence; 
           [0046]      FIG. 7  is an angled view of a positioning fence; 
           [0047]      FIG. 8  is an end view of a positioning fence; 
           [0048]      FIG. 9  is an end view of a permanent magnet bank; and 
           [0049]      FIG. 10  is an end view of an electromagnet bank. 
       
    
    
     DETAILED DESCRIPTION 
       [0050]    The inventions will now be explained with reference to the non-limiting FIGs. 
         [0051]      FIGS. 1 and 2  show an embodiment of the positioning fence of the present inventions, generally depicted by reference numeral  10 . The positioning fence has a continuous track  16  extending between an opposed set of end rollers  14 . The width of the track  16  is generally about 3 feet, but any desired width can by used. The top of the track  16  moves in a left to right direction, as shown by the arrow A. The track  16  includes a plurality of paddles  18  spaced along the continuous track  16  corresponding to the lumber spacing of the individual lumber pieces that the lumber position fence will be used to position. The paddles  18  have a surface  19  for interacting with the lumber pieces as shown in  FIG. 3 . 
         [0052]    At least one of end rollers  14  is driven to cause the track  16  and the paddles  18  to move in a longitudinal direction, that is in the direction of travel of the lumber, which is generally depicted by arrow A. End roller  14  can be driven by and in time with the lumber conveyor or by a separate drive that follows the movement of the lumber coveyor exactly. At least one of the paddles  18  is mounted for lateral sliding movement across the width of the track loop along a bearing way  20 . The bearing way  20  is oriented for lateral movement of the paddle  18 , which is a direction perpendicular to the longitudinal direction of the track  16 . 
         [0053]      FIG. 3  shows a side view of a paddle  18  mounted on a bearing way  20 . The paddle  18  having a locking mechanism constructed and arranged to lock the lateral position of the at least one paddle. The locking mechanism comprises a movable pin  22  biased in a closed position by a spring  24 . The pin  22  has a pad  26  that is attracted to a magnetic source. The bearing way  20  has a plurality of detents  28  along a length of the bearing way sized to receive the pin  22  when in the closed position. Preferably, the detents  28  are located about 0.1 to 3 inches apart, more preferably about 0.2 to about 1 inch apart, and most preferably about 0.5 inch apart. 
         [0054]    As shown in  FIGS. 1-3 , an actuator magnet bank  30  is disposed at an angle β across the width of the track  16 . The actuator magnet bank  30  comprises at least one electromagnet that can be activated and deactivated. The actuator magnet bank  30  is constructed and arranged such that when activated, the pad  26  is magnetically attracted to the actuator magnet bank  30  and the pin  22  moves to an open position where the end of the pin  22  is not inserted in the detent  28  on the bearing way  20 . When the pin  22  is an open position, the paddle  18  is free to move along the length of the bearing way  20 . When the actuator magnet bank  30  is deactivated the end of the pin  20  is inserted in the detent  28  on the bearing way by the spring  24  to lock the position of the paddle  18  on the bearing way  20 . While a linear actuator magnet bank  30  is shown, a non-linear actuator magnet bank  30  can be used if desired. The angle β of the actuator bank  30  can be as desired for the particular application. In general, the greater the angle β the faster the paddle  18  will travel along the bearing way  20  as the track  16  moves. When using a linear track, examples of suitable angles β are from 1 to 80 degrees, preferably from 5 to 60 degrees, more preferably about 10 to about 35 degrees. 
         [0055]    A paddle roller magnet bank  32  is disposed at an angle β across the width of the track  16 . The paddle roller magnet bank  32  can comprise a permanent magnet and/or an electromagnet. The paddle  18  has a metal surface  40  that is magnetically attracted to the paddle roller magnet bank  32 . Thus, when the track  16  is moving in the left to right direction shown in  FIGS. 1-2 , the metal surface  40  is magnetically bound to the paddle roller magnet bank  32  and moves the paddle  18  from a starting position shown at  33  along the bearing way  20  while the actuator magnet bank  30  is activated and the pin  22  is in the unlocked position. When a desired position of the paddle  18  on the bearing way  20  is obtained, the actuator magnet bank  30  is deactivated and the pin  22  is inserted in a detent  28 , the paddle  18  is locked, and as the track  16  continues to move the metal surface  40  is pulled away from the paddle roller magnet bank  32  and the paddle  18  continues to move in the direction of the track  16 . Preferably, the paddle roller magnet bank  32  and the actuator magnet bank  30  have the same angle β. When a magnet bank  30  is used having a length in which more than one paddle  18  will be traveling along the length at a time, the magnet bank  30  comprises a plurality of electromagnets and the individual electromagnets can be activated and deactivated independently of one another to separately control each paddle  18  location. 
         [0056]    A paddle reset slide  34  is disposed at an angle φ across the track  16 . The paddle reset slide  34  is constructed and arranged to move the paddles  18  back into the starting position  33 . The paddle reset slide  34  can comprise a magnet bank or other means for moving the pin  22  into an open position and sliding the paddle  18  back to the starting position. The angle φ can be as desired for the particular application. In general, the greater the angle φ the faster the paddle  18  will travel along the bearing way  20  as the track  16  moves. Examples of suitable angles φ are from 1 to 80 degrees, preferably from 5 to 60 degrees, and more preferably about 10 to about 35 degrees. 
         [0057]    The detents  28  can be, for example, holes, depressions, cuts, or rack gears, as desired. If desired, in place the detents  28 , the pointed end of the pin  22  shown in  FIG. 3  can be replaced with a friction material so that location of the paddle  18  is not limited by the location of the detents and the end of the pin  22  contacts the bearing way  20  to lock the paddle  18  in place on the bearing way  20 . A cap can also be used, as further described below, which is disposed between the pin  22  and bearing way  20  so that the pin  22  contacts the bearing way  20  through the cap. 
         [0058]    Preferably, the paddle  18  and/or the paddle roller magnet bank  32  includes spacing structure to provide space between the paddle  18  and the paddle roller magnet bank  32  so that the paddle  18  does not hang up on the paddle roller magnet bank  32 . For example the spacing structure  42 , can be a wheel or a low friction surface, such as nylon or graphite, as desired. 
         [0059]    A programmable computer controller  50  is preferably used to control the operation of the actuator magnet bank  30 , and preferably individual electromagnets on the magnet bank  30 . The location of the paddles  18  can be known to the programmable computer controller  50  by calculation of the offset relative to the displacement of the lumber conveyor in the path of lumber travel as measured with an encoding device, at the known angle of the magnet banks. A commercial example of a suitable encoding device is an Electrocam PS4256 absolute grey code encoder. A commercial example of the programmable computer controller  50  is an A.B.ControLogix 5000 series. Any suitable controller  50  can be used. 
         [0060]      FIGS. 4-8  show another embodiment of the lumber positioning fence. Like reference numbers and letters are as described above unless otherwise stated.  FIG. 4  is a cut away view through the center of the positioning fence. The positioning fence has a continuous track  16  extending between an opposed set of end rollers  14 . The width of the track  16  is generally about 3 feet, but any desired width can be used. The top of the track  16  moves in a right to left direction, as shown by the arrow C in  FIGS. 5 and 6 . The track  16  includes a plurality of paddles  18  spaced along the continuous track  16  corresponding to the lumber spacing of the individual lumber pieces that the lumber position fence will be used to position. The paddles  18  have a surface  19  for interacting with the lumber pieces. 
         [0061]    At least one of the end rollers  14  are driven to cause the track  16  and the paddles  18  to move in a longitudinal direction, that is in the direction of travel of the lumber, which is generally depicted by arrow C. End roller  14  can be driven by and in time with the lumber conveyor or by a separate drive that follows the movement of the lumber coveyor exactly. At least one of the paddles  18  is mounted for lateral sliding movement across the width of the track loop along a bearing way  20 . The bearing way  20  is oriented for lateral movement of the paddle  18 , which is a direction perpendicular to the longitudinal direction of the track  16 . 
         [0062]    The paddle  18  has a locking mechanism constructed and arranged to lock the lateral position of the paddle on the bearing way  20 . The locking mechanism comprises a movable pin  22  biased in a closed position by a spring  24 . The pin  22  has a pad  26  located a second end of the pin  22 . The pad  26  has a first surface  60  facing away from the pin  22  that is attracted to a magnetic source and a second surface  61  that faces the pin  22 . When the pin  22  is in a closed position, a first end  23  of the pin  22  contacts the bearing way  20  to lock the paddle  18  in position on the bearing way  20 . Reference No. 25 shows the pin  22  in a lower position. An optional cap (not shown) can be used between the first end  23  of the pin  22  and the bearing way  20 . The cap can be formed from any desired material. If desired, the bearing way  20  can contain detents  28  in which the first end  23  of the pin  22  contacts the bearing way  20 . If the optional cap is present, the first end  23  will contact the bearing way  20  through the cap. While the preferred locking mechanism utilizes a pin  22 , any desired locking mechanism can be utilized so long as the locking mechanism can be controlled by the actuator magnet bank  30 . Examples of other locking mechanisms include clamps or other devices that contact the bearing way  20  in a closed position to lock the paddle  18  in position on the bearing way  20  so that the locking position is infinitely variable. 
         [0063]    An actuator magnet bank  30  is disposed at an angle β across the width of the track  16 . The actuator magnet bank  30  comprises an electromagnet that can be activated and deactivated. The actuator magnet bank  30  is constructed and arranged such that when activated, the pad  26  is magnetically attracted to the actuator magnet bank  30  and the pin  22  moves to an open position where the first end  23  of the pin  22  does not contact the bearing way  20 . When the pin  22  is an open position, the paddle  18  is free to move along the length of the bearing way  20 . When the actuator magnet bank  30  is deactivated the first end  23  of the pin  20  contacts the bearing way by the spring  24  to lock the position of the paddle  18  on the bearing way  20 . 
         [0064]    A paddle roller bank  132  is disposed at an angle β across the width of the track  16 . The paddle roller bank  132  comprises a depression  133  which is sized to receive a portion of a roller ball  134 . The paddle  18  includes a roller ball  134 , a roller ball receiver  135 , and a spring  136 . The spring  136  biases the roller ball  134  towards the depression  133 . 
         [0065]    Thus, when the track  16  is moving in the right to left direction shown in  FIGS. 4-8 , the roller ball  134  travels along the depression  133  and moves the paddle  18  from a starting position shown at  33  along the bearing way  20  while the actuator magnet bank  30  is activated and the pin  22  is in the unlocked position. If the length of the magnet bank  30  is such that more than one paddle  18  will be travelling along the length of the magnet bank  30  at the same time, the magnet bank  30  comprises a plurality of electromagnets and the individual electromagnets can be activated and deactivated at different times to control the position of each paddle  18  independently of one another. When a desired position of the paddle  18  on the bearing way  20  is obtained, the individual electromagnets on the actuator magnet bank  30  controlling the paddle  18  are deactivated and the first end  23  of pin  22  contacts the bearing way  20  and the paddle  18  is locked in position on the bearing way  20 , and as the track  16  continues to move the roller ball  134  retracts into the receiver  135  and leaves the depression  133  so that the paddle  18  is pulled away from the paddle roller bank  132  and the paddle  18  continues to move only in the direction of the track  16 . The paddle roller bank  132  can contain an optional safety bar  80  that prevents the roller ball  134  from exiting the wrong side of the depression  133 . 
         [0066]    A paddle reset slide  140  is disposed at an angle φ across the track  16 . Preferably, the paddle reset slide  140  is located on a bottom side of the track  16 . The paddle reset slide  140  is constructed and arranged to move the paddles  18  back into the starting position  33 . The paddle reset slide  140  has a sliding surface  141  that contacts the second surface  61  of the pad  26 . When the second surface  61  slides onto the sliding surface  141  as the track  16  moves the pad  26  is pulled in a direction away from the paddle  18 , thus moving the pin  22  away from the bearing way and unlocking the paddle  18 . The second surface  61  slides along the surface  141  as the track  16  moves to move the paddle  18  back to a starting position  33 . Once the paddle  18  reaches the starting position  33  the second surface  61  exits the sliding surface  141  and the first end  23  of the pin  22  contacts the bearing way  20  locking the paddle  18  in the starting position on the bearing way  20 . The pin  22  can rotate within the paddle  18 , thus allowing the surface  61  to rotate as it slides along the sliding surface  141  thereby increasing wearability and life of the pad  26 . The sliding surface  141  and the surface  61  are preferably formed from a low friction material, such as plastic. 
         [0067]    An example of the apparatus was tested. It was found that occasionally the pad  26  would come into contact with the magnet bank  30  when the pad  26  was pulled down too far by the magnet bank  30  during operation. Thus, preferably a slide bar  54 , such as UHMW plastic, is placed on the magnet bank  30  in a position so that if the pad  26  is pulled too far by the magnet bank  30  the pad  26  contacts the slide bar  54  and not the magnet bank  30 . 
         [0068]    It was also found that premature pin  22  wear can sometimes occur. Without being limited to any cause, it is believed that the pin  22  wear is from the paddle reset slide  140  where the pin  22  is pulled out of the detent hole  28  with the reset slide angle  140  and pushing the pin  22  over somewhat at the same time. To solve this problem a long magnet or shorter series of magnets can be placed the entire length of the paddle reset slide and located just out in front of the paddle reset slide  140 . The magnet can pull the pin  22  before hitting the return angle  140  and the pin  22  should be all the way out of the detent hole  28  before having to be pushed back to the zero position. Even though a permanent or earth magnet would work, as shown in  FIG. 9 , preferably an electromagnet, as shown in  FIG. 10 , is utilized so that when the electromagnet is turned off when it is not being used, the magnet can be cleared of any metallic debris the magnet may attract.  FIG. 9  illustrates permanent magnets embedded in an aluminum block, and slide bar  54 . The permanent magnet does not have to be embedded, and if the permanent magnet is embedded, any suitable material can be used. An example of a suitable magnet structure is the paddle reset slide  34  described herein above. The paddle reset slide  34  can be used in place of the paddle reset slide  140  or in combination with the paddle reset slide  140 .  FIG. 4  shows the paddle reset slide  34 , in the form of a magnet bank with optional slide bar  54 , as shown in  FIGS. 9 and 10 , used in combination with the paddle reset slide  140 . In this manner, if the magnet in the paddle reset slide  34  does not fully disengage the pin  22  from the detent hole  28 , the paddle reset slide  140  will ensure that the pin  22  is fully removed from the detent hole  28 . Alternatively, the paddle reset slide  34  can be used in combination with a slide bar, which comprises the vertical wall shown as part of the paddle reset slide  140  in  FIG. 4 . 
         [0069]    An example of the apparatus having seventeen paddles  18  was tested. It was found that the paddles  18  all acted a little differently. Each paddle  18  tested had forty nine set points (defined by detents  28 ), along 0″ to 24″ on 0.5″ increments, which is a total of 833 (49×17) individual set points. Thus, seventeen individual timing tables with individual encoder counts for each set point were set up. In addition to that, the paddle  18  timing points appeared to change with temperature, wear and other unknown factors. Timing of the paddles  18  would be a tedious task to do manually and cannot be done while the paddles  18  are in the operational mode. To correct for these changes, an auto-timing feature was added. With the addition of a paddle position sensor  58 , such as a laser sensor, located on the out-feed side of the track  16  and connected to the controller  50 , the exact location of the paddle  18  can be determined. The exact location of the paddle  18  can then be compared to the set point that the paddle  18  should have gone to. Knowing the difference (+/−) between the actual location and the set point, the controller can automatically adjust the individual encoder counts for that individual set point within that individual table to correct for the inaccuracy or miss-set of the paddle  18 . This adjustability is also useful when setting up the paddle  18  as it will time itself rather than having to spend several hours doing it manually. 
         [0070]    The temperature of the magnet  30  may be a concern. The magnet  30  should not be run too hot nor too cool. The timing seems to change with magnet temperature. Thus, an auto-temp feature is preferably included with the addition of thermocouple(s)  56  connected to the controller  50 . Preferably, each electro magnet  30  has an associated thermocouple  56  for measuring the temperature of the magnet  30 . Since the magnet  30  cools off when not in use, the control can automatically turn the magnet  30  on early to reach the desired running temperature or even hold the magnet  30  at that temperature overnight if desired. While not required, knowing the magnet temperature seems to be beneficial in making the apparatus function better. 
         [0071]    The invention also relates to a method of locating a piece of lumber on a conveyor that is transporting the lumber with one end of the lumber contacting the surface  19  of the paddle  18 . During use, a piece of lumber being transported on the conveyor is urged toward the paddle  18  traveling on track  16 . The paddle  18  prevents further movement of the lumber in a direction perpendicular to the travel of the track  16  when the locking mechanism is switched to a closed position which locks the paddle  18  in place on the bearing way  20 . The track  16  continues to move separating the paddle  18  from the paddle roller bank  32  or  132  by continuing to move the track  16  while the paddle  18  is in a locked position on the bearing way  20  so that the lumber only travels in the direction of the track. Once the lumber is in a desired position, it will continue to be transferred downstream to a trimmer where the lumber can be cut to size. After the lumber has exited the track, the paddle  18  is returned to a starting position  33 . 
         [0072]    While the claimed invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one of ordinary skill in the art that various changes and modifications can be made to the claimed invention without departing from the sprit and scope thereof.