Winch Drum Assembly for Kink-Free Container Lifting Tethers
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Solution Overview
Problem
Existing load handling devices for storage containers in automated storage systems face issues with the susceptibility of lifting tapes to kinking, leading to uneven tether lengths and potential failure in maintaining a horizontal orientation, especially under heavy loads.
Innovation Solution
The use of elongated drums with axially displaced turns of lifting tethers, allowing for precise control of tether length and preventing kinking, along with a guide member to ensure uniform winding and unwinding, accommodates various types of tethers like ropes or cables, ensuring the container gripping assembly remains horizontal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lifting tapes are used to suspend the container gripping assembly, then the lifting mechanism can support heavy loads, but the tapes are susceptible to kinking which causes uneven tether lengths and potential failure
Solution Approach 1:
The patent changes the geometric parameters of the drum from a conventional circular cross-section to an elongated shape with dimensions specifically designed to accommodate the tether. The drum has a length L and diameter D where L>D, creating an elongated structure that guides the tether along its length and prevents kinking while maintaining load bearing capacity.
Solution Approach 2:
The elongated drum acts as an intermediary component between the tether and the spool assembly. It provides a controlled interface that guides the tether, distributes wear evenly, and prevents direct contact between the tether and the spool, thereby eliminating kinking while maintaining strength.
2Length of moving object
If multiple layers of lifting tape are wound on a spool, then the tether length can be controlled, but the tape thickness and layering make precise length control difficult
Solution Approach 1:
The patent transitions from controlling tether length through radial layering (2D spool surface) to controlling it through axial distribution along the elongated drum (adding a dimensional aspect). The tether is distributed along the length L of the drum rather than stacked radially, allowing more precise control over the effective tether length.
3Volume of moving object
If thin lifting tapes are used to enable multiple overlaps on a spool, then the mechanism can accommodate deep storage, but the tapes are more susceptible to damage and kinking
Solution Approach 1:
The elongated drum serves as a protective intermediary between the thin tether and the spool assembly. It distributes the mechanical stresses and prevents direct folding or kinking of the thin tether, thereby protecting vulnerable thin tapes from damage while still enabling deep storage capability.
4Ease of operation
If separate spools are used for each lifting tether, then each tether can be independently controlled, but the complexity of the lifting mechanism increases
Solution Approach 1:
The patent merges multiple spool functions into a single elongated drum structure. The drum combines the functions of multiple spools into one unified component that accommodates all tethers along its length, reducing the number of separate rotating elements while maintaining independent control capability through the elongated geometry.
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 solution provides a robust and flexible lifting mechanism that maintains the container gripping assembly's horizontal orientation, reduces wear on lifting tethers, and allows for the use of different tether materials, enhancing the reliability and longevity of the load handling device.
Implementation Method 1
an elongated drum rotatable about its central axis of rotation
Implementation Method 2
the elongated drum having an outer surface that is configured to accommodate a plurality of axially displaced turns of the lifting tether such that rotation of the drum causes the lifting tether to coil around the outer surface of the drum
Data Source
AI summary
A load handling device is provided for lifting and moving containers stacked in a storage system including a grid framework. The load handling device includes a vehicle body housing a wheel drive mechanism and a wheel assembly. A container lifting assembly comprising a container gripping assembly, a plurality of winch assemblies each includes a rotatable drum and a lifting tether anchored at a first end to the gripping assembly and at a second end to the drum, and a drive assembly configured to drive rotation of the drums to raise the gripping assembly into a container receiving space. Each drum has an outer surface configured to accommodate a plurality of axially displaced turns of the lifting tether across the drum.