Concrete Wall Step Iron Detent Locking for Low-Force Anchoring

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Solution Overview

Problem

Existing methods for fastening step irons in concrete walls require high impact loads during assembly to ensure pull-out resistance, risking mechanical damage, especially to plastic-coated tread bars, and complicate easy replacement.

Innovation Solution

A detent assembly with a radially sprung detent tongue and a peripheral guide surface is introduced between anchor sleeves and anchor bolts, allowing for secure fastening with low assembly forces and enabling easy replacement by radially displacing the detent tongue along the guide surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If threaded anchor bolts are driven into plastic anchor sleeves to ensure pull-out resistance, then the pull-out resistance is improved, but the assembly forces required increase and mechanical damage to the step iron occurs

Engineering Contradiction:

Improvepull-out resistanceVSAvoidassembly forces

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The coupling between anchor bolt and anchor sleeve is segmented into two independent functions: insertion (guided by the tapered guide surface) and locking (performed by the detent tongue in the detent recess). This separation allows low insertion forces while maintaining high pull-out resistance through the detent mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The detent tongue acts as an intermediary element between the anchor bolt and anchor sleeve. It provides the locking function that ensures pull-out resistance without requiring the high forces that would otherwise be needed to deform plastic materials during insertion.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If threaded anchor bolts are used to ensure pull-out resistance, then the hold security is improved, but the replacement complexity increases due to the need to unscrew bolts

Engineering Contradiction:

Improvepull-out resistanceVSAvoidreplacement simplicity

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

Instead of using a threaded connection that requires unscrewing for removal, the invention uses a detent-based mechanical lock that is released by reversing the insertion motion. The tapered guide surface allows the detent tongue to be pushed out radially during removal, inverting the typical screw-unthreading operation into a simpler push-out motion.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The detent tongue is made resilient and can dynamically transition between engaged and disengaged states. During installation, it is compressed radially to pass the detent recess; during removal, the taper on the guide surface automatically pushes it out of engagement, providing a simple dynamic release mechanism.

Inventive Principle:

Principle #15Dynamics

3Strength

If high impact loads are applied during assembly to ensure pull-out resistance, then the anchoring strength is improved, but the risk of mechanical damage to plastic coatings increases

Engineering Contradiction:

Improveanchoring strengthVSAvoidmechanical damage risk

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The detent assembly is designed to absorb and cushion the insertion forces through the resilient detent tongue and the controlled deformation along the tapered guide surface. This prevents the transmission of high impact loads to the step iron and its plastic coating, while still ensuring proper engagement and anchoring strength.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 solution provides secure hold and protection against pull-out while reducing assembly forces and allowing for simple step iron replacement without mechanical damage, as the detent assembly's predefined pull-out resistance is independent of insertion forces and can be released by rotating the anchor bolts.

Implementation Method 1

a detent assembly formed from at least one detent tongue which is sprung in the radial direction

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 2

the anchor bolts can be rotated about their axis in the direction of the guide surface, with the effect that the detent tongue moves out of the detent recess in the peripheral direction

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS11814900B2Device for securing a rung in a concrete wall

Publication Date: 2023.11.14 SCHLUSSELBAUER ULRICH

AI summary

A device has two anchor sleeves (3) in a concrete wall (2) accommodating two parallel anchor bolts (6) of a U-shaped step iron (1) form-fittingly. Between coupling parts formed by the anchor sleeves (3) and the anchor bolts (6), a detent assembly (7) has at least one detent tongue (8) sprung in the radial direction on one of the coupling parts (3, 6) and a detent recess (9) that receives the detent tongue (8) on the other coupling part (6, 3). A guide surface (15) for the detent tongue (8) is inclined in the peripheral direction and extends in the radial direction over the engagement depth of the detent tongue (8) adjoining the detent recess (9) at least in a peripheral direction.