Pivoting Fall Protection Base Plate Reduces Roof Torque
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Solution Overview
Problem
Existing fall protection devices for flat roofs with trapezoidal sheet metal constructions fail to minimize torque and prevent damage during falls, as the lever arm extension leads to increased forces on the roof structure, causing the trapezoidal sheets to tear off due to adhesion.
Innovation Solution
The device features a base plate with a central area connected to the peripheral area via narrow material webs and additional straight slots, allowing the post to pivot horizontally, reducing the lever arm and minimizing torque, with circumferential slots extending over 270° and additional slots creating a hinge to facilitate this pivoting, thereby distributing tensile forces horizontally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base plate is fastened to the trapezoidal sheet with a post extending upward, then fall protection function is provided, but the lever arm is extended and torque increases causing the trapezoidal sheet to tear off
Solution Approach 1:
The base plate is segmented into a central area and a peripheral area connected by narrow material webs. The central area can pivot relative to the peripheral area, allowing the post to fold horizontally during a fall, thereby shortening the lever arm and reducing torque on the roof structure while maintaining fall protection functionality
Solution Approach 2:
The base plate transitions from a static rigid structure to a dynamic structure with pivot capability. The central area pivots horizontally relative to the peripheral area when load is applied, enabling the post to fold and reduce the lever arm, thus dynamically adapting to fall loads and minimizing damage to the roof structure
2Strength
If the post is designed to withstand lateral impact forces, then impact protection is provided, but the tensile force creates a moment that increases tearing out force on the anchorage
Solution Approach 1:
The base plate is divided into central and peripheral areas that can move relative to each other. This segmentation allows the central area with the post to pivot independently, converting the tensile force into a pivoting motion that reduces the moment and tearing out force on the anchorage while maintaining impact resistance
Solution Approach 2:
The tensile force that would normally create a harmful moment and increase tearing out force is converted into a beneficial pivoting motion. The central area pivots horizontally, causing the post to fold and convert the harmful tensile moment into a controlled folding action that reduces overall stress on the anchorage
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
This design shortens the lever arm, prevents damage to the roof structure, and ensures the trapezoidal sheet metal remains attached, as the tensile force is absorbed by the peripheral area's anchoring, which is designed to handle 1.2 t lateral forces without tearing off.
Implementation Method 1
The central area is only connected to the remaining peripheral area of the base plate via narrow material webs, allowing the post to pivot horizontally
Implementation Method 2
with circumferential slots extending over 270° and additional slots creating a hinge to facilitate this pivoting, thereby distributing tensile forces horizontally
Data Source
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AI summary
The invention relates to a device for preventing persons from falling, in particular from a roof, comprising a foot plate (10) which can be secured to an underlying surface and which comprises a stop point that can be attached to the foot plate, comprising either a post which projects upwards from the foot plate and which comprises an eyelet arranged in the upper end region of the post or an eyelet which can be introduced directly into the foot plate, in each case for attaching a cable by means of which the person is prevented from falling. According to the invention, a foot plate central region, in which the post or the eyelet is connected to the foot plate, is slotted around the post or the eyelet along at least one first defined circumferential slotted line (18a), which extends over at least approximately 270° in the circumferential direction, such that the central region is connected to the rest of the peripheral region of the foot plate (10) solely via narrow material webs (18b). In the event of a load, a type of joint is produced along the foot plate (10) sheet webs remaining between the slots, and the central region lying within the circumferential slotted line pivots together with the posts secured to the region upwards out of the plane of the footplate on the basis of the lifting force acting via the posts. The posts can thus lie flatly, and a torque is no longer acting on the peripheral region of the foot plate.