Fiber Rope Drum End Fastening with Guide Channels and Fold-Back Clamping
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Solution Overview
Problem
High-strength fiber ropes pose challenges in attaching the rope end to a cable drum due to low coefficient of friction and limited transverse compressive strength, requiring additional safety windings and complex mounting configurations, which can lead to rope damage and hinder threading through pulleys.
Innovation Solution
A cable drum design featuring strand guide channels and a clamping device that folds the rope end back around a handling element, generating high holding forces through U-shaped wrapping and clamping, allowing for secure attachment without spliced rope eyes and minimizing clamping forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional steel rope attachment methods are used with high-strength fiber ropes, then the attachment structure remains simple, but the rope end loosens due to low coefficient of friction
Solution Approach 1:
The attachment structure is segmented into multiple functional components: a drum body for winding, flanged wheels for guiding, and a cable end attachment device with clamping jaws and safety windings. This segmentation allows each component to address specific aspects of the retention problem independently.
Solution Approach 2:
The rope end is pre-secured through multiple safety windings (at least three) around the drum body before final attachment. This preliminary action creates initial friction retention that reduces the load on the clamping jaws, compensating for the low coefficient of friction of fiber ropes.
2Reliability
If clamping force is increased to secure fiber rope attachment, then rope retention improves, but rope damage occurs due to limited transverse compressive strength
Solution Approach 1:
The design changes the attachment parameters by using multiple clamping jaws distributed along the rope end rather than a single high-force clamp. This distributes the clamping force across multiple contact points, reducing the force per unit area and preventing structural damage to the fiber rope.
Solution Approach 2:
The clamping jaws are designed with cushioning features and distributed arrangement to prevent concentrated stress on the rope. The safety windings also serve as a cushioning mechanism, absorbing some of the tension and reducing the peak clamping force required at the attachment point.
3Reliability
If multiple safety windings are added to compensate for low friction, then rope retention improves, but device complexity increases
Solution Approach 1:
The drum body serves multiple functions: it winds the rope during operation, provides the surface for safety windings to create friction retention, and acts as the core structure for the entire attachment device. This multi-functionality reduces the need for additional specialized components.
Solution Approach 2:
The safety windings are integrated directly into the existing drum body structure rather than being separate components. The flanged wheels are merged with the drum assembly, creating a compact unified structure that provides both guidance and friction retention without adding excessive complexity.
4Ease of manufacture
If rope end is routed outside flanged wheel for clamping, then attachment is achieved, but threading through pulleys becomes difficult
Solution Approach 1:
The flanged wheels act as intermediary elements that guide the rope from the drum body to the clamping jaws. These wheels provide a smooth transition path that facilitates easy threading through pulleys while still allowing the rope end to be routed outside for proper clamping attachment.
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 enhances rope holding forces while reducing clamping force requirements, ensuring secure attachment without damaging the fiber rope and facilitating easy threading through pulleys, thus improving the reliability and efficiency of fiber rope drives.
Implementation Method 1
the coefficient of friction for the high-strength fiber rope is only around 0.05 μ. This means that for the same end-of-rope pull for the high-tenacity fiber rope, at least seven safety turns would be required to achieve the same entrapment friction retention force.
Implementation Method 2
a clamping device assigned to the strand guide channels for clamping at least the Rope strand, which is folded back around the rope handling element, in the strand guide channel assigned to this rope strand.
Data Source
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AI summary
The invention relates to rope drives operating with high-strength fiber ropes, such as crane hoisting gear, boom adjustment units, trolley running gears, and the like. The invention relates in particular to a rope drum (1) for such a fiber rope drive, having a drum body (2) for winding the fiber rope, flanged wheels (3) enclosing the drum body, and a rope end fastening device (9) for fastening a rope end to the rope drum. According to the invention, the rope end fastening device of the rope drum comprises two adjacent strand guiding channels (13, 14), which lead to a rope deflection element (15), around which the rope end can be passed, such that one rope strand comes to lie in each of the two strand guiding channels, and furthermore a clamping device (26) provided for the strand guiding channels for clamping at least the rope strand that is passed back around the rope deflection element, in the strand guiding channel provided for said rope strand.