Bottom up lumber stacker

A lumber stacking machine comprising:

• an infeed station, a stacking station and a staging station;
• a first conveyor operable to move individual pieces of lumber from said infeed station into said stacking station to form a layer of said individual pieces of lumber in said stacking station with said individual pieces of lumber being oriented in parallel orientations;
• a second conveyor selectively operable to move a stack of lumber from said stacking station to said staging station, said first and second conveyors overlapping in said stacking station, said first conveyor incorporating a relief mechanism to retract said first conveyor within said stacking station when said stack of lumber is lowered to engage said layer of individual pieces within said stacking station so that said stack of lumber is supported on said second conveyor instead of said first conveyor;
• and
• a stacking mechanism operable in said stacking station to form said stack of lumber from subsequent layers of individual pieces of lumber conveyed into said stacking station, said stacking mechanism being operable to elevate a newly formed layer of lumber into a stack of lumber vertically elevated above said stacking station such that said stack of lumber is formed from the bottom side until completed so that said second conveyor can transport said completed stack of lumber to said staging station, said stacking mechanism including a pair of opposing stack holders operably connected to a drive mechanism for simultaneously reciprocating said stack holders vertically, each said stack holder having a plurality of stacking fingers selectively movable between extended and retracted positions by linear actuators engaged with said stacking fingers to power horizontal movement thereof, said stack holders also being vertically movable to elevate a stack of lumber above said stacking station while a new layer of individual pieces of lumber is being formed on said stacking station, and a control mechanism for initiating the operation of said relief mechanism in response to a predetermined movement of said stack holders, said stacking fingers being extended to engage a lowermost layer of lumber of said elevated stack of lumber, and retracted when said stack holders are lowered to add said newly formed layer of lumber to allow said stack holders to pass below said newly formed layer of lumber, said relief mechanism being operable to lower said first conveyor when said completed stack of lumber is placed upon said stacking station to enable said selectively operable second conveyor to move said completed stack of lumber from said stacking station to said staging station.

A lumber stacking machine comprising:

• an infeed station having a first conveyor continuously operable to move individual pieces of lumber along a path of movement;
• a stacking station in which said first conveyor terminates so as to deliver said individual pieces of lumber in an orientation transverse to said path of movement from said infeed station to form a layer of lumber within said stacking station, said stacking station supporting the beginning of a second conveyor selectively operable to move a completed stack of lumber from said stacking station, said first and second conveyors overlapping in said stacking station, said stacking station further having a pair of opposing stacking members operable to hold a partially formed stack of lumber vertically above said stacking station while said layer of lumber is being formed, and sequentially move a plurality of subsequently formed completed layers of lumber onto a bottom portion of said partially formed stack of lumber to create said completed stack of lumber, each said stacking member including a pair of opposing stack holders, each said stack holder having a plurality of stacking fingers operably connected to a pair of linear actuators to selectively move said stacking fingers horizontally between extended and retracted positions, said stack holders being vertically movable to elevate a stack of lumber above said stacking station while a new layer of individual pieces of lumber is being formed on said stacking station, said linear actuators being operable to extend said stacking fingers to engage a lowermost layer of lumber of said elevated stack of lumber, and to retract said stacking fingers when said stack holders are lowered to add said newly formed layer of lumber to said partially formed stack of lumber, said stacking station including a relief mechanism operable to lower said first conveyor when said completed stack of lumber is placed upon said stacking station to enable said second conveyor to move said completed stack of lumber from said stacking station to said staging station, said relief mechanism being operable to retract said first conveyor below said second conveyor within said stacking station, said second conveyor being operated selectively when said completed stack of lumber is to be conveyed to said staging station;
• and
• a staging station supporting a terminus of said second conveyor to receive said completed stack of lumber from said stacking station.