Removable Fall Arrest Reel for Manhole Access Safety
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Solution Overview
Problem
Existing restraint systems for accessing manholes via a well are inadequate in ensuring worker safety, particularly during descent and rescue operations, as they can be obstructive, increase installation complexity, and do not allow secure anchoring for all workers involved.
Innovation Solution
A removable fall arrest reel-unwinder rod system with anchor points and a cable winching device, where the rod is erected vertically with a winching device at the upper end and a base fixed to the well wall, providing secure anchoring and fall arrest capabilities while allowing safe handling and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cable fall arrest system with tripod restraint is installed, then worker safety during descent is improved, but installation complexity and access obstruction increase
Solution Approach 1:
The system is divided into separate functional components: a removable rod with fall arrest reel that can be independently installed and removed, separate from the permanent base installation. This segmentation allows the complex fall arrest function to be added only when needed without permanently complicating the basic access structure.
Solution Approach 2:
The fall arrest reel-unwinder is extracted as a removable component that can be taken out of the rod when not in use. This extraction principle reduces installation complexity by allowing the system to be configured in different modes (with or without fall arrest capability) while maintaining the permanent base installation.
2Reliability
If a cable fall arrest system is installed, then fall arrest capability is improved, but access to the well is obstructed
Solution Approach 1:
The rod with fall arrest reel is designed to be dynamically removable and reconfigurable. It can be inserted into the permanent base when fall arrest is needed, and removed when not needed, allowing the system to adapt its configuration based on operational requirements rather than permanently obstructing access.
Solution Approach 2:
The rod extends vertically from the base, utilizing the vertical dimension of the well access point. This allows the fall arrest mechanism to be positioned in the vertical space above the manhole opening, rather than obstructing the horizontal access path.
3Reliability
If multiple workers need to be secured, then safety coverage is improved, but system complexity increases
Solution Approach 1:
The permanent base installation serves multiple functions: it provides structural support for the rod, acts as an anchor point for fall arrest operations, and can accommodate different rod configurations. This multi-functionality allows the same base structure to support safety operations for multiple workers without requiring separate installation systems for each worker.
Solution Approach 2:
The rod acts as an intermediary component between the permanent base and the workers. It provides a standardized interface that can accommodate different numbers of workers and different operational scenarios, simplifying the system architecture compared to direct worker-to-base connections.
4Adaptability or versatility
If the rod is made removable for flexibility, then adaptability is improved, but anchoring security may be compromised
Solution Approach 1:
The permanent base is pre-installed in the well structure during the initial construction phase, establishing a secure anchoring foundation before any removable rod components are added. This preliminary action ensures that the anchoring security is established by the permanent structure rather than the removable components.
Solution Approach 2:
The removable rod with fall arrest reel is nested within or upon the permanent base structure. The rod fits into or attaches to the pre-installed base, creating a hierarchical arrangement where the permanent base provides the secure anchoring while the removable rod provides flexible functionality.
Data Source
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AI summary
The invention relates to a personnel restraint system for a descending access shaft accessible from above through a manhole (2), the system comprising a removable restraint pole (1) and a pole installation base (20), the pole (1) being extended longitudinally between two ends, a lower end (15) and an upper end (16), the upper end (16) of the pole (1) having an anchoring element (11, 12), the installation base (20) being fixed to a wall of the shaft, the lower end (15) of the pole being able to be removably immobilized in the installation base (20), the system being configured so that, when the pole (1) is immobilized in the installation base (20), the pole (1) is erected upwards and the upper end (16) of the pole is at a determined height above the level of the manhole (2).According to the invention, the system comprises a winching device (31, 50) with a cable (34), the free end of the cable (34) having an attachment device (39), said winching device (31, 50) being carried by a rod (30) removably fixed to the upper end (16) of the pole (1). The winching device may be a fall arrest winder-reeler (31) or a manual winch (50).