Fork assembly for lumber stackers

Abstract

The fork assembly for lumber stackers includes a plurality of mechanized arms. Each mechanized arm includes a biasing assembly that provides a movable carrying surface onto the arm upper surface Such movable carrying surface is for example in the form of an endless belt, that biases an object deposited onto the arm towards a distal end thereof. The fork assembly according to the present invention prevents smaller pieces of lumber to rise when the fork assembly is retracted above a lumber stacker elevator during deposition of the lumber from the fork assembly to the elevator's platform. The present invention further allows creating stack of lumbers having different configurations.

What is claimed is:  
     
         1 . A mechanized arm for a lumber stacker comprising: 
 a body;    a longitudinal arm mounted to said body and having a proximate end and a distal end and generally extending from said body from said proximate end along a longitudinal axis;    a biasing assembly mounted on said longitudinal arm; said biasing assembly defining a carrying surface on said longitudinal arm; said carrying surface being movable along said longitudinal axis, and    a biasing assembly actuator in operative relation with said biasing assembly for moving said carrying surface;    whereby an object deposited onto said longitudinal arm is biased towards said distal end of said arm by actuating said biasing assembly using said biasing assembly actuator.    
     
     
         2 . A mechanized arm as recited in  claim 1 , wherein said longitudinal arm includes a belt-receiving portion and said biasing assembly includes a drive pulley so mounted to said body as to be complementary aligned with said belt-receiving portion, and an endless belt rotatably mounted to said drive pulley and said belt-receiving portion.  
     
     
         3 . A mechanized arm as recited in  claim 2 , wherein said biasing assembly further includes at least one of an upper guide pulley mounted to said body near said proximate end of said longitudinal arm and a bottom guide pulley mounted to said longitudinal arm below said belt-receiving portion.  
     
     
         4 . A mechanized arm as recited in  claim 3 , wherein said biasing assembly is so position relatively to said drive pulley as to define an upward slope portion of said belt.  
     
     
         5 . A mechanized arm as recited in  claim 2 , wherein said biasing assembly further includes a belt idler assembly.  
     
     
         6 . A mechanized arm as recited in  claim 1 , wherein said longitudinal arm has a generally triangular profile defining a downward slope from said proximate end to said distal end of said longitudinal arm.  
     
     
         7 . A fork assembly for a lumber stacker comprising: 
 a plurality of mechanized arms as recited in  claim 1 , each of said mechanized arms being mounted to the lumber stacker as to be movable along each of said mechanized arm longitudinal axis; said plurality of mechanized arms being so positioned in a parallel relationship as to generally yield said mechanized arms carrying surfaces in a first plane; and    at least one drive system mounted to the lumber stacker and coupled to said mechanized arms for causing translation movements of said plurality of mechanized arms along its respective longitudinal axis.    
     
     
         8 . A fork assembly as recited in  claim 7 , further comprising a controller connected to both said at least one drive system and each of said biasing assembly actuator for operating said at least one drive system and each of said biasing assembly actuator.  
     
     
         9 . A fork assembly as recited in  claim 8 , wherein said controller further allows determining a relative speed between each of said carrying surface of said plurality of mechanized arms and said plurality of mechanized arms.  
     
     
         10 . A fork assembly as recited in  claim 7 , further comprising a carriage so mounted to said at least one drive system as to be movable along said longitudinal axis; said plurality of mechanized arms being mounted to said carriage; 
 whereby, operation of said at least one drive system causing translation of said plurality of mechanized arms along said longitudinal axis.    
     
     
         11 . A fork assembly as recited in  claim 10 , wherein said plurality of mechanized arms being pivotally mounted to said carriage.  
     
     
         12 . A fork assembly as recited in  claim 10 , wherein said longitudinal arm includes a belt-receiving portion and said biasing assembly includes a drive pulley so mounted to said body as to be complementary aligned with said belt-receiving portion and an endless belt rotatably mounted to said drive pulley and said belt-receiving portion.  
     
     
         13 . A fork assembly as recited in  claim 12 , wherein said biasing assembly actuator includes a motor and at least one drive assembly for transmitting the energy of said motor to said biasing assembly.  
     
     
         14 . A fork assembly as recited in  claim 13 , wherein said plurality of mechanized arms being mounted to said carriage via a rotatable mounting shaft positioned generally perpendicular to said longitudinal axes; said at least one drive assembly including a first drive assembly for transmitting the energy of said motor to said rotatable mounting shaft, and a second drive assembly for transmitting the energy of said rotatable mounting shaft to said biasing assembly; 
 whereby actuation of said motor causes the actuation biasing assembly via said first and second drive assembly.    
     
     
         15 . A fork assembly as recited in  claim 14 , wherein said first drive assembly includes a first drive wheel mounted to a drive shaft of said motor, and a first driven wheel fixedly mounted to said rotatable mounting shaft and being coupled to said first drive wheel for rotation in unison; said second drive assembly includes a second drive wheel fixedly mounted to said mounting shaft and rotatably mounted to said body, a second driven wheel rotatably mounted to said body and coupled to said second drive wheel for rotation in unison, and a shaft mounted to said body and coaxially mounted to said second driven wheel and said drive pulley.  
     
     
         16 . A lumber stacker comprising: 
 a mounting structure;    a lumber transfer apparatus mounted to said mounting frame structure for receiving wood lumbers, aligning wood lumbers parallel to a second axis, in a second plan, and for moving wood lumbers, in said second plan, in a second direction perpendicular to said second axis; said lumber transfer apparatus including a series of parallel spaced conveyor belts;    an elevator mounted to said mounting structure positioned adjacent said lumber transfer apparatus and including a platform movable along an axis perpendicular to both said second plan and said second direction;    a fork assembly as recited in  claim 2  mounted to said mounting structure, said fork assembly being so configured and sized and so positioned relative to said lumber transfer apparatus and said elevator as to be movable between a first position wherein said arms of said fork assembly generally overlap said belts of said lumber transfer apparatus, to a second position wherein said arms extend above said elevator;    a first stop mounted to said mounting structure so as to allow passage of lumbers from said lumber transfer apparatus to said fork assembly when said fork assembly is in its second position and to force lumbers on said fork assembly from said fork assembly to said platform of said elevator when said fork assembly is moved from said second position to said first position; and    a second stop so mounted to said mounting structure opposite said first stop relatively to said elevator as to be positioned in a moving path of said fork assembly