Brush Chipper Feed Stop Bar Pivot Axis Inversion
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Solution Overview
Problem
Existing lower feed stop bars in brush chippers are prone to nuisance trips due to the force of gravity and machine vibrations, causing false stops during dynamic loading and transport.
Innovation Solution
The lower feed stop bar is designed with a pivot axis located below the control bar and towards the brush chipper, and an elastic member provides additional force to rotate it in the opposite direction of feed cessation, ensuring it remains in a tripped position during transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lower feed stop bar is pivoted with the axis above the control bar towards the outfeed end, then the stop bar can be actuated by gravity and operator force, but it causes nuisance trips due to gravity and vibrations forcing the bar toward its forward position
Solution Approach 1:
The patent inverts the conventional pivot axis location by placing it below the control bar instead of above it. This inversion changes the gravitational effect from causing nuisance trips to preventing them, while still allowing operator actuation. The center of mass is positioned to the left of the pivot axis, creating a counter-clockwise rotational tendency that opposes the clockwise motion caused by gravity during normal operation.
Solution Approach 2:
The patent uses the weight of the stop bar itself as a counterweight by positioning the center of mass to the left of the pivot axis. This creates a gravitational moment that counteracts the harmful gravitational effect on the right side of the pivot, preventing nuisance trips during dynamic loading and transport while maintaining operational responsiveness.
2Force
If the pivot axis is positioned to the left of the mass of the feed stop bar, then gravity creates a rotational tendency, but machine vibrations and accelerations cause the bar to rotate in the wrong direction during transport
Solution Approach 1:
The patent addresses the two-dimensional problem of gravitational force and vibration-induced rotation by introducing a third dimension through the vertical placement of the pivot axis below the control bar. This spatial reconfiguration creates a moment arm geometry where gravity produces a beneficial counter-clockwise rotational tendency that stabilizes the stop bar position during transport, overriding the harmful effects of vertical accelerations.
3Ease of operation
If the lower feed stop bar is designed to be actuated by gravity toward the forward position, then it responds to operator input, but it cannot maintain a tripped position during machine transport
Solution Approach 1:
The patent enables the stop bar to self-stabilize in the tripped position during transport through its own weight distribution. By positioning the center of mass to the left of the pivot axis, the bar's weight automatically creates a counter-clockwise moment that maintains the tripped position without requiring external forces or additional stabilization mechanisms, while still allowing operator actuation when needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design significantly reduces false trips by managing accelerations and maintains safety and efficiency during transport by ensuring the feed has ceased.
Implementation Method 1
an elastic member provides additional force to rotate it in the opposite direction of feed cessation
Implementation Method 2
the force of gravity, aggravated by machine vibrations, tends to force the lower feed stop bar toward its forward position
Data Source
AI summary
A control mechanism for the feed of a brush chipper is disclosed. A lower feed stop bar, located under a feed table, pivots on a pivot axis located below and toward the brush chipper from the control bar of the lower feed stop bar. The center of gravity of the lower feed stop bar, then, tends to pivot the lower feed stop bar away from the feed disengage position. Hence, nuisance trips due to vibration, impact of brush on the table, etc., are reduced.