Rope Exoskeleton Structure for Cut-Resistant Single-Plane Bending
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Solution Overview
Problem
Existing elongate bodies, such as flexible cables or chains, lack sufficient resistance to cutting attempts and are easily accessible for unauthorized cutting, especially when used in security devices like bicycle or motorcycle locks.
Innovation Solution
An elongate body comprising a rope enclosed within closely spaced tubular elements that allow relative rotation and form an exoskeleton, which must be breached before cutting, with restricted bending in one direction and reinforced by cut-resistant materials, and optionally enclosed in shells or locking units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a simple rope or chain is used, then the device is easy to manufacture and operate, but it offers insufficient resistance to cutting attempts
Solution Approach 1:
The rope is divided into sections by inserting tubular elements at intervals along its length. These tubular elements segment the continuous rope into discrete protected sections, creating an exoskeleton structure that must be breached before the rope can be cut. This segmentation provides cutting resistance while maintaining relative structural simplicity.
Solution Approach 2:
The tubular elements are positioned around and enclose the rope, creating a nested structure where the rope is contained within the tubular exoskeleton. This nesting arrangement protects the rope from direct access and cutting attempts while keeping the overall structure relatively compact and manageable.
2Strength
If tubular elements are added to protect the rope, then cutting resistance is improved, but the device becomes more complex
Solution Approach 1:
Rather than making the entire rope structure uniformly complex, the invention applies tubular protective elements only at specific intervals along the rope. This local application of protection provides cutting resistance where needed while minimizing the overall increase in device complexity and maintaining sections of simple rope between protected zones.
Solution Approach 2:
The tubular elements function as flexible protective shells that enclose the rope. These shells provide cutting resistance through their structural form and material properties while maintaining flexibility to allow the overall device to bend and flex as needed, avoiding excessive complexity.
3Strength
If the rope is fully enclosed in rigid tubes, then cutting resistance is maximized, but the body cannot bend
Solution Approach 1:
By segmenting the rope protection into discrete tubular elements spaced at intervals rather than using a continuous rigid enclosure, the invention allows bending to occur at the sections between tubes while maintaining cutting resistance at the protected zones. This segmentation enables both protection and flexibility.
Solution Approach 2:
The tubular elements are designed to allow relative movement and rotation with respect to each other and the rope, creating a dynamic structure that can adapt to bending forces. This dynamic arrangement enables the body to bend while the tubular elements maintain their protective function through controlled movement rather than rigid fixation.
4Adaptability or versatility
If tubular elements allow relative rotation, then bending is enabled, but the structure becomes less stable
Solution Approach 1:
The invention provides different degrees of stability at different locations: the tubular elements provide stable, fixed protection at their positions while allowing controlled movement between elements. This local differentiation enables bending flexibility where needed while maintaining structural stability at the protected zones.
Solution Approach 2:
The invention merges two seemingly contradictory requirements by combining the stability of fixed tubular protective elements with the flexibility of allowed relative movement between them. This merging creates a hybrid structure that exhibits both stability for cutting resistance and flexibility for bending capability.
Data Source
AI summary
An elongate body adapted to bend in a single plane, comprises a rope extending within a succession of individual tubular elements closely spaced along the rope. Each element has on two opposite sides of the plane an extended section engaging a recess in its neighbouring element, the profiles of the section and recess allowing relative rotation of adjacent elements in said plane. The tubular elements thus form an exoskeleton around the rope which must be breached before the rope can be cut. The geometry of the tubular elements can be such that notwithstanding gaps, the rope cannot be readily accessed unless the exoskeleton is broken.