Hinged Connecting Element for Fall Arrester Oscillation Isolation
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Solution Overview
Problem
Existing fall arresters can be inadvertently released from their arrested state due to oscillating movements of the secured person, failing to securely lock in place during a fall and potentially allowing re-release of the arrest force.
Innovation Solution
A hinged connecting element is attached to the pawl, which minimizes the transmission of oscillating movements to the pawl, ensuring it cannot release itself from the arrested state, and is designed as a damping element that deforms to absorb fall energy, limiting the arrest force to a safe level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the connecting element is rigidly connected to the pawl, then oscillating movements are transmitted to the pawl causing inadvertent release, but the connecting element cannot effectively dampen fall energy
Solution Approach 1:
The hinge connection acts as an intermediary between the connecting element and the pawl. It decouples the oscillating movements from the pawl while maintaining the structural connection needed for force transmission during normal operation. The hinge allows relative rotation, serving as a mediator that filters out harmful oscillations while preserving the functional connection.
Solution Approach 2:
The connection between the connecting element and the pawl is segmented into two functional parts: the hinge connection that allows oscillation isolation, and the force transmission path that remains intact during arrest. This segmentation enables the system to simultaneously achieve oscillation isolation and effective force transmission.
2Loss of energy
If the connecting element is formed as a deformable damping element, then fall energy is absorbed and arrest force is reduced, but the structural integrity may be compromised
Solution Approach 1:
The connecting element's shape parameters are specifically designed to control deformation behavior. By optimizing the geometry (such as curved or zigzag configurations), the element undergoes controlled plastic deformation during fall arrest, absorbing energy while maintaining sufficient structural integrity. The parameter optimization ensures the element deforms within safe limits to protect the user.
Solution Approach 2:
The potential weakness of a deformable element is converted into a benefit: the controlled deformation during fall arrest transforms the harmful fall energy into beneficial energy absorption. The deformation that might seem to compromise strength actually serves to limit the arrest force to safe levels, protecting the user from excessive forces.
3Reliability
If the pawl is pre-stressed by a spring to press against catching stops, then secure locking is achieved, but the oscillating movements can still release the positive locking
Solution Approach 1:
The hinge connection serves as a mediator that protects the pre-stressed pawl from oscillating movements. It allows the pawl to maintain its pre-stressed state for secure locking while isolating it from the oscillations that would otherwise cause inadvertent release. The hinge filters out the harmful oscillations while preserving the locking function.
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 hinged connecting element effectively secures the fall arrester in place during a fall, damping the arrest force and preventing unintended release, ensuring secure locking and controlled force distribution.
Implementation Method 1
the damping element is deformed into a more rectilinear shape by the fall energy, whereby the fall arrest force is damped
Implementation Method 2
Fall energy is reduced by the stretching and the fall arrest force is thereby damped
Implementation Method 3
The pawl is pre-stressed by a spring, with the result that the pawl tooth is pressed against the catching stops in the rear of the guide rail
Data Source
AI summary
The fall arrester (10) is part of a climbing protection system for preventing a user of a ladder, a platform or the like from falling. The fall arrester (10) is movable along a guide rail (12) and has a rotatably mounted pawl (18) which, in the event of a fall, runs against catching stops (16) in the guide rail (12). A connecting element (40) is attached to the pawl (18) and the user can be secured to the connecting element (40) by a lanyard. The connecting element (40) is hinged to the pawl (18). The connecting element (40) can be hinged to the pawl (18) such that the connecting element (40) is coupled releasably rotation-resistant to the pawl (18) and the coupling (50, 52) is released in the event of a predetermined force on the connecting element (40). The connecting element can be formed as a damping element (40) which deforms in the event of a predetermined force.