Cable Grab Lever and Energy Absorber for Shorter Fall Arrest
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Solution Overview
Problem
Current fall arrest devices for wire rope safety lines in ladder systems extend the fall distance and stress the lever arm, indicating a need for improved mechanisms to effectively engage and arrest falls while minimizing user stress and design constraints.
Innovation Solution
A cable grab system comprising a channel for receiving a safety wire, a cam to grab the wire during a fall, a lever for rotating and engaging the cam, and an energy absorber with a working length and webbing portion to absorb fall forces, along with a channel cover that can be easily locked and unlocked for secure attachment and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lever arm is directly linked through a chain of load bearing components to the user's harness, then the fall arrest device can effectively arrest a fall, but the fall distance is extended and the lever arm is stressed
Solution Approach 1:
The patent extracts the energy absorber from the direct load path between the lever arm and the user's harness. By removing this intermediate chain of load bearing components, the fall distance is reduced while the lever arm is still effectively stressed to engage the cam mechanism for reliable fall arrest.
Solution Approach 2:
The patent introduces the energy absorber as a mediator that absorbs fall energy through deformation rather than transmitting it directly through rigid load bearing components. This intermediary element reduces the fall distance by controlling the energy absorption process, while still allowing the lever arm to be properly stressed for cam engagement.
2Volume of moving object
If the energy absorber is integrated with the lever arm, then the structure is compact, but the design complexity increases and user weight limits are constrained
Solution Approach 1:
The patent segments the fall arrest device into distinct functional components: the lever arm mechanism for cam engagement and the energy absorber for energy dissipation. This segmentation simplifies the design of each individual component while maintaining overall compactness, and allows for greater user weight limits by distributing the functional requirements across separate elements.
3Reliability
If the channel cover is always locked to prevent access, then the safety wire is protected, but the device cannot be attached or detached
Solution Approach 1:
The patent implements a preliminary locking action where the channel cover is默认 locked to protect the safety wire, but includes a simple release mechanism that allows users to easily unlock and open the cover when attachment or detachment is needed. This preliminary protective state is maintained until deliberately changed by the user.
Solution Approach 2:
The channel cover mechanism is designed to be self-locking through its normal operation, automatically protecting the safety wire without requiring external intervention. The simple release mechanism allows users to easily override this self-service locking function when needed for attachment or detachment operations.
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
The cable grab system reduces fall distance, distributes arresting forces effectively, prevents attachment in inverted orientations, and allows for simpler design and increased user weight limits by separating the energy absorber from the lever, enhancing the overall safety and usability of fall protection systems.
Implementation Method 1
a cam structured to grab the safety wire in the event of a fall
Implementation Method 2
an energy absorber having a working length, a normal webbing portion, and a connection point, wherein the working length or the normal webbing portion are structured to engage the lever in the event of a fall
Data Source
AI summary
A cable grab for a fall protection system includes a channel for receiving a safety wire, a cam structured to grab the safety wire in the event of a fall, a lever structured to rotate and cause the cam to grab the safety wire in the event of a fall, and an energy absorber having a working length, a normal webbing portion, and a connection point, wherein the working length or the normal webbing portion are structured to engage the lever in the event of a fall.