Compact Pulley Assembly for Telescopic Boom Visibility
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Solution Overview
Problem
The existing pulley assemblies for telescopic booms require a large diameter pivot pin to accommodate adjustment bolts, leading to a large pulley size that impairs operator visibility of the load due to increased diameter.
Innovation Solution
A pulley assembly design where adjustment rods engage the pulley frame, which in turn moves the pulley along the pivot pin, allowing for independent sizing of the pivot pin and pulley frame, maintaining a compact pulley size without compromising strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adjustment bolts are threaded into the pivot pin to adjust chain wear, then the chain can be adjusted to resynchronize boom positions, but the pivot pin must be of larger diameter which increases pulley size and impairs operator visibility
Solution Approach 1:
The invention divides the adjustment mechanism into separate components: adjustment bolts are separated from the pivot pin and instead engage with the pulley frame. This segmentation allows the pivot pin to be sized solely for its structural and rotational functions, while the adjustment mechanism is integrated into the pulley frame, enabling independent optimization of both components.
Solution Approach 2:
The pulley frame acts as an intermediary element that mediates between the adjustment bolts and the pivot pin. The bolts engage the pulley frame, which in turn engages the pivot pin, allowing force transmission for chain adjustment without requiring the bolts to directly engage the pivot pin. This intermediary structure enables smaller pivot pin diameter while maintaining adjustment capability.
2Strength
If a larger diameter pivot pin is used to accommodate adjustment bolts, then the threaded hole can withstand loads, but the pulley diameter increases impairing visibility
Solution Approach 1:
The invention separates the load-bearing function from the adjustment function. The pivot pin is optimized for rotational strength and load bearing with appropriate diameter, while the adjustment function is transferred to the pulley frame through dedicated adjustment bolt engagement points. This allows each component to be optimally sized for its specific function without compromise.
Solution Approach 2:
The adjustment mechanism is moved from the radial dimension (threaded hole in pivot pin) to the axial dimension (engagement with pulley frame). This dimensional shift allows the pivot pin diameter to be minimized for visibility while the adjustment bolts engage the pulley frame in a different spatial arrangement that maintains structural integrity.
Data Source
AI summary
A boom assembly including a boom defining a longitudinal direction pulley rotatably mounted on a pivot pin, the pivot pin having a first end with a first outer surface and a second end with a second outer surface, a pulley frame having a first part for receiving the first outer surface, a second part for receiving the second outer surface, a first hole for receiving a first adjustment rod and a second hole for receiving a second adjustment rod, the boom including a first receiving portion for receiving the first adjustment rod and a second receiving portion for receiving the second adjustment rod, the boom assembly being configured such that adjustment of the first and second adjustment rods causes movement of the pulley in the longitudinal direction.