Safety Harness Ventral Blocker for Fall Arrest
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Solution Overview
Problem
Existing rope harnesses for work at height safety often result in awkward suspension positions due to the resistance not passing through a blocker, and some lack upper safety attachment points, compromising safety, especially in caving and other height work scenarios.
Innovation Solution
A tie-in harness design featuring integrated ascenders with a sternal attachment buckle and adjustable buckles, where the ascender serves both as a suspension retainer and a strong connection between the ventral and sternal attachment points, providing an upper fall arrest safety attachment and multiple work positioning configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the ascender is fixed in parallel on the strap between the sternal point and belt, then the ascender can retain suspension on the work rope, but the resistance does not pass through the blocker resulting in awkward position in suspension
Solution Approach 1:
The patent merges the ascender attachment function with the ventral blocker connection. The ascender is attached to the ventral attachment means rather than being fixed in parallel on a separate strap, so that the resistance force passes through the blocker. This integration eliminates the awkward suspension position while maintaining the ascender's retention function, resolving the contradiction between ease of operation and device complexity.
Solution Approach 2:
The ventral blocker serves as an intermediary element that transmits the resistance force from the ascender to the belt structure. By positioning the ascender to work through the blocker rather than via a separate parallel connection, the blocker mediates the force transmission path, ensuring proper suspension position and force distribution without requiring complex additional connection structures.
2Device complexity
If a simple leg strap with ascender is used as in caving harnesses, then the structure is simple, but there is no upper safety attachment point making it unsuitable for work at heights
Solution Approach 1:
The patent applies multi-functionality by designing the ventral attachment means to serve dual purposes: it acts as the attachment point for the ascender for work positioning, and simultaneously provides the upper safety attachment point for fall arrest through its connection to the sternal attachment loop via the blocker. This eliminates the need for separate simple leg strap configurations while ensuring reliability for work at heights.
Solution Approach 2:
The harness is segmented into distinct functional components: the ventral attachment means for ascender connection, the sternal attachment loop for upper safety attachment, and the blocker for force transmission. This segmentation allows each component to fulfill specific safety functions while maintaining overall structural simplicity, meeting both the simplicity requirement and the reliability need for upper safety attachment.
3Reliability
If the ventral attachment point is connected to sternal attachment point by a strong strap, then safety connection is established, but the installation of ascender requires separate fixing resulting in complex structure
Solution Approach 1:
The patent combines the ascender attachment function with the existing ventral-to-sternal connection system. Instead of requiring separate fixing of the ascender on a parallel strap, the ascender is attached to the ventral attachment means which is already part of the strong safety connection system. This merging approach maintains reliable safety connection while simplifying ascender installation and reducing overall structure complexity.
Data Source
Figure 1
Figure 2
AI summary
The harness (10) has a belt (13) equipped with a ventral fastener loop (19), and a pair of shoulder straps (14, 15) joined by a sternal fastener loop (22) having an antifall upper fastener point. The sternal fastener loop is located above the ventral fastener loop having a lower fastener loop. A trigger or cam type ventral blocker (23) is inserted between the fastener loops to ensure a resistant connection between the straps and a leg strap formed by a pair of thigh girths (11, 12) and the belt. The belt and the thigh girths are internally folded twice with breathable cushioned foam.