Wheeled Fall Arrestor with Pneumatic Arm and Gripping Plate
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Solution Overview
Problem
Existing fall arresting safety devices are not easily mobile and require complex setups, making them inefficient for use on flat roof surfaces or construction sites without exterior walls, where workers need to move freely while being protected from falls.
Innovation Solution
A fall arrestor assembly with a pivotally attached arrestor arm and a gas-filled cylinder to maintain the arm above the surface, connected by a tether that engages a toothed gripping plate into the surface upon a fall, allowing for immediate resistance to prevent further falling, mounted on a wheeled cart for mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If existing fall arresting safety devices are used, then fall protection is provided, but mobility is poor and setup is complex
Solution Approach 1:
The fall arrestor is divided into separate functional components: a mobile support unit (cart or stand), a pivotally attached arrestor arm, and a tether system. This segmentation allows each component to be optimized independently - the support provides mobility while the arm provides fall arrest function, reducing overall setup complexity.
Solution Approach 2:
The arrestor arm is designed to be dynamic rather than static - it pivots from an upright position during normal work to a horizontal engaged position during fall arrest. This dynamic transformation allows the device to adapt between mobility mode (arm clear of surface) and safety mode (arm engaged with surface), eliminating the need for complex manual setup.
2Ease of operation
If the arrestor arm is held above the surface during normal work, then worker mobility is enabled, but fall protection readiness may be compromised
Solution Approach 1:
The arrestor arm dynamically transitions between two states: upright position during normal work allowing worker mobility, and horizontal engaged position during fall arrest providing protection. The pivot mechanism ensures the arm is always in the appropriate position for the current operational state, maintaining both mobility and protection readiness.
Solution Approach 2:
The gas-filled cylinder automatically positions the arrestor arm in the upright state during normal work without manual intervention. Upon fall detection, the same cylinder automatically transitions the arm to the engaged position, eliminating the need for worker intervention and ensuring reliable fall protection readiness.
3Extent of automation
If a gas filled cylinder is used to maintain the arm position, then automatic positioning is achieved, but device weight increases
Solution Approach 1:
A gas-filled cylinder uses pneumatic pressure to automatically position and hold the arrestor arm in the upright state during normal work. The gas pressure provides continuous upward force on the arm, eliminating the need for manual positioning or heavy mechanical springs, thereby achieving automation with moderate weight increase.
4Reliability
If the gripping plate engages the surface upon fall, then immediate resistance is provided, but the gripping plate may be damaged
Solution Approach 1:
The toothed gripping plate is pre-positioned on the arrestor arm, ready to engage the surface immediately upon fall detection. The teeth are already formed and positioned to bite into the surface material, eliminating the need for pre-assembled complex engagement mechanisms and ensuring rapid response while distributing impact forces across multiple tooth elements.
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 solution provides a mobile and easily deployable fall arrestor system that allows workers to move freely while ensuring immediate resistance to falls, enhancing safety on flat roofs and construction sites without the need for complex setups.
Implementation Method 1
a gas filled cylinder that provides just sufficient pressure to maintain the arm and gripping plate spaced from the surface
Implementation Method 2
the tether exerts a pull or a pulling force against the arm having the gripping plate connected thereto. The pulling force is directly proportional to the weight of the worker and the velocity of the worker's fall
Implementation Method 3
allows the pulling force generated by the falling worker to jamb the gripping plate into the surface to provide a resistance to terminate the fall of the worker
Data Source
AI summary
A roofing worker safety device is provided that delivers a resistive force in response to a worker falling from an elevated work surface such as a roof via a safety cable connecting the worker to the safety device, the cable transmitting the force of the falling worker to the device to activate an arrestor arm that is forced into the surface on which the safety device is placed thereby stopping the fall of a worker from the roof.