Self-retracting lifeline emergency engaging assembly
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Solution Overview
Problem
Conventional self-retracting lifeline devices face issues such as guide pin breakage due to excessive force, unreliable helical springs that tend to slip, and slow operation of single pawls, which can lead to malfunction and increased risk of falls for workers at height.
Innovation Solution
The self-retracting lifeline device incorporates a housing with increased contact area for enhanced counter-force and structural strength, an elastic member that stably urges against fastening projections without slipping, and an emergency engaging assembly with multiple engaging members and protuberances to ensure immediate stopping of the rope seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a guide pin is used in the guiding slot to limit movement direction and distance of the pawl, then the movement control is improved, but the guide pin may break due to excessive force exerted thereon
Solution Approach 1:
The patent removes the guide pin from the system entirely. Instead of using a guide pin in a guiding slot to control pawl movement, the invention uses the engagement between the pawl's engaging edge and the protrusion on the housing to directly control and limit the pawl's movement direction and distance, thereby eliminating the weak guide pin component that could break under excessive force.
2Duration of action of moving object
If a helical spring urges against an arcuate outer surface of the shaft to return the pawl to original position, then the restoration function is achieved, but the spring tends to slip and is not reliable
Solution Approach 1:
The patent changes the spring's engagement surface from a curved arcuate surface to a localized flat stop surface on the shaft. This flat stop surface provides a stable, non-slipping contact area for the spring, improving reliability while maintaining the restoration function. The localized flat surface ensures the spring remains securely positioned during operation.
3Device complexity
If a single pawl is provided to engage the protrusion for emergency stopping, then the device structure is simplified, but the pawl acts slowly and is high risk in operation
Solution Approach 1:
The patent divides the single pawl into multiple segmented pawls (first pawl and second pawl) that can engage the protrusion simultaneously or sequentially. This segmentation allows for faster engagement response because multiple pawls can contact the protrusion at different positions, distributing the engagement force and reducing the time required for complete engagement, thereby reducing operational risk while maintaining structural simplicity.
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 device provides increased structural strength, stable operation, and enhanced emergency engagement capabilities, significantly reducing the risk of falls for workers at height by ensuring reliable and immediate activation of the lifeline.
Implementation Method 1
an elastic member disposed in the restoration space and having a first fastening end for securing the elastic member to the seat positioning member, and a second fastening end for securing the elastic member to the disc positioning member
Implementation Method 2
in response to a centrifugal force exceeding force exerted by at least one of the elastic elements, at least one of the engaging members is thrown toward the engaging ring
Data Source
AI summary
A self-retracting lifeline device includes a housing including a suspension ring, opposing, downward extending first and second extensions, and a pivot pivotably disposed through the first and second extensions; a rope seat rotatably disposed on the pivot between the first extension and the second extension, the rope seat including opposing first and second discs, a rope winding drum, and fastening projections; a restoration assembly disposed on the pivot and between the first extension and the rope seat, the restoration assembly including a restoration seat and an elastic member; and an emergency engaging assembly disposed on the pivot and between the second extension and the rope seat, the emergency engaging assembly including an engaging seat, engaging members, two parallel walls, a protrusion, elastic elements, and an engaging ring. In response to a centrifugal force exceeding force exerted by the elastic element, the rotation of the rope seat is stopped.