Bottom Up Lumber Stacking Mechanism With Retractable Fingers
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Solution Overview
Problem
Conventional lumber stacking machines face challenges in accommodating different lengths of lumber at high operating speeds while maintaining lower production costs, as they typically build stacks from the top and struggle with efficiency, especially with shorter boards.
Innovation Solution
A lumber stacking machine that stacks lumber from the bottom up, utilizing retractable stacking fingers and a cyclical drive mechanism, with a second conveyor and spacing adjustment mechanism to accommodate various lengths, and vertically movable stops for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional top-down stacking is used, then the stacking structure is simple, but the stacking speed is insufficient for high-speed production
Solution Approach 1:
The patent inverts the conventional stacking approach by building the stack from the bottom up rather than from the top down. The stacking mechanism engages with the bottom of the stack and progressively builds upward, which enables higher stacking speeds while maintaining a relatively simple mechanical structure. This inversion allows the stack to be formed in a single continuous motion rather than requiring complex multi-directional arm movements.
2Adaptability or versatility
If conventional stacking arms are used, then the manufacturing cost is lower, but the ability to handle varying lumber lengths is limited
Solution Approach 1:
The stacking mechanism incorporates dynamic elements including adjustable stacking fingers that can be positioned at different heights and angles, and a cyclical drive mechanism that adapts its motion profile to accommodate varying lumber lengths. The conveyor system also provides dynamic positioning capabilities, allowing the mechanism to efficiently handle both short and long boards without requiring complex reconfiguration or significantly increasing manufacturing complexity.
3Productivity
If top-down stacking is used, then the mechanism is simpler, but the efficiency with shorter boards is reduced
Solution Approach 1:
The stacking mechanism employs locally optimized features including retractable stacking fingers that can extend and retract to match the length of the lumber being stacked. The cyclical drive mechanism provides different motion characteristics at different stages of the stacking cycle, with accelerated motion for shorter boards and controlled motion for longer boards. This localized adaptation significantly improves handling efficiency for shorter boards while maintaining overall system simplicity.
Data Source
AI summary
A lumber stacking machine has a stacking mechanism forming a stack of lumber from the bottom upwardly. The stacking mechanism includes a lift mechanism formed with a plurality of stacking fingers that lift a layer of lumber vertically above a conveyor. With the formation of a new layer of lumber, the stacking mechanism moves below the new layer with the stacking fingers retracting to pass by the new layer and resting the growing stack of lumber on top of the new layer, and then extending below the new layer to raise the entire stack to allow another new layer to be formed. Stops are provided to control the movement of the individual boards from the infeed station into the stacking station and also to control movement of the new layer beyond the stacking station. Two conveyors cooperate to move the lumber with an overlap in the stacking station.