Dynamic Attachment Point Safety Harness for Fall Arrest
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Solution Overview
Problem
Existing fall arrest safety harnesses with low attachment points tend to cause users to tilt excessively during falls, exceeding the 50° angle limit, due to their design and the resulting center of gravity positioning, and existing hooking systems are prone to neck impacts and reduced resistance control.
Innovation Solution
A safety harness with an umbilical hooking mechanism that moves upwards to a final position above the user's head during a fall, utilizing energy-dissipating seams to redistribute the user's center of gravity, featuring a first low-resistance and a second high-resistance fastening means to manage tensile forces effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the attachment means is positioned low (umbilical position) for ergonomic freedom of movement, then the user's freedom of movement at thorax level is improved, but the user's center of gravity is near or above the attachment means causing excessive tilting angle greater than 50° during fall arrest
Solution Approach 1:
The attachment means is designed to dynamically change its position relative to the user's body during a fall. The connection includes a first low-resistance fixing means that can yield and a second fastening means that provides high resistance, allowing the attachment means to move from the umbilical position upward to a final position above the user's head, thereby adapting the attachment point location based on the fall condition to maintain proper body orientation
Solution Approach 2:
The connection between the attachment means and the harness assembly is segmented into two distinct fastening means: a first low-resistance fixing means (seams with yield force between 150-600 daN) and a second high-resistance fastening means (force greater than fall force). This segmentation allows controlled movement of the attachment means during a fall, enabling it to transition from the umbilical position to a higher position above the user's head, resolving the contradiction between low attachment for ergonomics and high attachment for stability
2Device complexity
If a fixed low attachment point is used, then the harness structure is simple, but the user tends to tilt with upper part down at an angle greater than 50° in the event of a fall
Solution Approach 1:
The attachment means transitions from a fixed low position to a dynamic position that moves upward during a fall. The yieldable first fixing means allows the attachment means to move relative to the user's body, transforming the static harness structure into a dynamic system that automatically adjusts the attachment point location to maintain proper body orientation and prevent excessive tilting
3Stability of the object's composition
If movable hooking systems are used to allow attachment means movement, then the attachment means can relocate during fall, but the hook may impact the neck and the resistance level is reduced and difficult to control
Solution Approach 1:
The resistance characteristics of the connection are changed by using seam-based fastening means with controlled yield properties. The first fixing means has a specified yield force range (150-600 daN) that provides controlled resistance during attachment means movement, preventing both neck impact and uncontrolled movement. This parameter control through material and structural design of the seams replaces the need for mechanical hooks with unpredictable resistance characteristics
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 harness effectively limits user tilting by relocating the attachment point above the user's center of gravity, ensuring the user remains upright post-fall and maintaining control during falls, while preventing neck impacts and improving resistance management.
Implementation Method 1
the first low-resistance fixing means R1 which can yield in the event of a fall, R1 being less than the force which said means undergoes during a fall of the user equipped with the harness
Implementation Method 2
R2 being greater than the force which said means undergoes during a fall of the user equipped with the harness
Implementation Method 3
The fixing means used to fix the hooking means on the harness comprises means for dissipating energy during the fall, in the form of seams which gradually give way when the fall is arrested
Data Source
Figure 1~4
AI summary
The invention relates to a safety harness (1) for stopping the fall of a user, which comprises an assembly of straps intended for being passed around the body of the user and suitable for supporting said user, and a means (5) for hooking onto a fall-prevention system connected by a link to said assembly. According to the invention, the link comprises a first low-strength R1 attachment means (3), which can give in the event of a fall, R1 being lower than the force to which said means is subjected during a fall of the user fitted with the harness; and a second high-strength R2 attachment means (4), which does not give in the event of a fall, R2 being higher than the force to which said means is subjected during a fall of the user fitted with the harness, in order for the initially umbilical hooking means to move upwards relative to the user, when subjected to a pulling force such that the first attachment means gives, into a final position of said hooking means in which said means is blocked due to the strength of the second attachment means.