Fall Arresting Safety Apparatus with Acute-Angle Engaging Member
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Solution Overview
Problem
Conventional safety apparatuses for arresting falls from elevated surfaces face issues with insufficient gripping force due to penetration depth and risk of unhooking during hoisting, particularly with inverted U-shaped attachment elements that can unhook if hooks become slack.
Innovation Solution
A safety apparatus featuring a frame unit with a pulley system, a slide mechanism, and an engaging member with acute-angle teeth that grips the surface when the worker falls, combined with lifting attachments that prevent unintentional unhooking by guiding hooks securely through shaped passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engaging member pivots about a pivot axis to grip the surface, then the safety apparatus can arrest a fall, but the penetration depth is insufficient leading to inadequate gripping force
Solution Approach 1:
The engaging member transitions from a static pivoting mechanism to a dynamic penetrating mechanism. The member is designed to be forceable into the surface, converting the fall force directly into penetration motion rather than relying on pivoting action. This dynamic approach ensures sufficient penetration depth while maintaining reliable gripping.
Solution Approach 2:
The engaging member geometry is optimized with specific parameters including an acute angle (20-45 degrees) relative to the slide axis, and dimensions designed to achieve adequate penetration depth. The member length extends 0.5-2 inches beyond the slide in the lower position, ensuring proper engagement with the surface while maintaining the ability to arrest falls reliably.
2Ease of operation
If conventional inverted U-shaped attachment elements are used for hoisting, then the apparatus can be lifted to the surface, but the hooks are liable to unhook if the hook lines become slack
Solution Approach 1:
The lifting attachment elements are pre-configured with specific geometric features (passages with acute angles) that guide the hooks into proper engagement positions before hoisting begins. The passages are designed to automatically position hooks correctly, preventing unhooking even if lines become slack during operation.
Solution Approach 2:
The lifting attachment elements serve as intermediary structures between the hooks and the frame unit. These attachments include passages that act as guiding intermediaries, ensuring hooks remain properly engaged during hoisting and preventing direct contact between hooks and the frame unit that could lead to unhooking.
3Device complexity
If the slide is mounted parallel to the rotation axis, then the structure is simplified, but the engaging member cannot effectively grip the surface during fall arrest
Solution Approach 1:
The slide is intentionally mounted at an asymmetric angle (non-parallel) to the rotation axis, creating a specific geometric relationship that enables effective fall arrest. This asymmetric mounting angle (between 0-45 degrees relative to perpendicular of rotation axis) allows the engaging member to properly engage the surface while the pulley rotates, ensuring both structural functionality and fall arrest effectiveness.
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 apparatus effectively arrests falls by ensuring deep penetration and secure gripping of the surface, while the lifting attachments prevent unhooking during hoisting, providing reliable worker safety and equipment stability.
Implementation Method 1
A biasing member is mounted between the slide and the frame unit and biases the slide from the lower position to the upper position
Implementation Method 2
A pulley is rotatably mounted to the frame unit about a rotation axis spaced from the surface
Implementation Method 3
The engaging member grips the surface when the slide is in the lower position, preventing further falling of the worker
Data Source
AI summary
A safety apparatus (10) includes a frame unit (12) placed on a surface (102). A cable (62) is mounted around a pulley (60) rotatably mounted to the frame unit (12) about a rotation axis (58). A slide (90) is slideably mounted to the frame unit (12) along a slide axis (92) at a non-parallel angle to the rotation axis (58) and movable between upper and lower positions. The cable (62) is attached between the slide (90) and a worker (100) on the surface (102). A biasing member (110) is mounted between the slide (90) and the frame unit (12) and biases the slide (90) from the lower position to the upper position. An engaging member (120) is mounted to the slide (90) to move therewith. The engaging member (120) is above the surface (102) when the slide (90) is in the upper position. If the worker (100) falls from the surface, the engaging member (120) is moved downward and grips the surface (102) under the action of force resulting from falling of the worker (100) to retain the safety apparatus (10) on the surface and, thus, arrests the fall of the worker (100) from the surface (102).