TECHNICAL FIELD

The present invention relates to lumber stacking machines and, more particularly, to a modular single-fork lumber stacking machine with a controller, board width sensor, and an adjustable stop to load layers of boards with varying widths onto a lift table with justified edges and distributed dead space.

BACKGROUND OF THE INVENTION

Lumber saws cut logs into boards of consistent thickness but varying width as the diameter of the sawn log changes. The boards of varying width are often stacked onto pallets for storage and shipping. Layers of boards assembled from boards of varying width generally vary in the overall layer width resulting in a stack with a jagged edge. Stack handling can be improved by justifying the layers to avoid jagged edges. According to one approach, the varying width boards are sorted into groups of boards with similar width to facilitate justified stacking. This approach requires expensive equipment to sort the boards into groups of similar width. Alternatively, dual-fork stackers have been used to distribute the dead space between the boards of each layer. This approach requires forks on both sides of the stack, which duplicates the number of forks and blocks access to both sides of the stack requiring equipment to be moved out of the way, or a full stack to be moved from the stacking table to allow a forklift to access to remove the stack. There is a need for an improved lumber stacker that avoids the drawbacks of these conventional lumber stacking machines.

SUMMARY OF THE INVENTION

The present invention meets the needs described above through a modular single-fork lumber stacking machine that utilizes a controller, board width sensor, and an adjustable stop to load layers of boards with varying widths onto a lift table. The single-fork design allows a fork lift to readily access the opposing side of the lift table to remove a multi-layer stack of boards assembled on the lift table. The controller, board width sensor, and adjustable stop may be used to justify the leading and trailing edges of the stack to avoid jagged stack edges. These features may also be used to distribute the dead space horizontally within each layer, and vertically between the layers, to stabilize the stack. The modular design includes a stacker module and a separate loader module that allows a forklift to separately lift, move and position each module to facilitate relocation and repositioning of the machine.

It will be understood that specific embodiments may include a variety of features in different combinations, as desired by different users. The specific techniques and structures for implementing particular embodiments of the invention and accomplishing the associated advantages will become apparent from the following detailed description of the embodiments and the appended drawings and claims.

