Sleeve Lock for Reinforcing Bar Stability

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Solution Overview

Problem

Existing methods for stabilizing vertically extending concrete reinforcing steel bars in poured concrete construction sites require significant manual effort and time, with internally threaded sleeves allowing free rotation but posing challenges in maintaining rotational and axial restraint, and often necessitating workers to ascend the structure for adjustments, which is unsafe.

Innovation Solution

The use of smooth bore sleeves with a locking mechanism that allows the reinforcing steel bars to spin freely within the sleeves, eliminating the need for tightening locks at elevated heights by providing stable couplings that can be locked in place before vertical erection, thereby reducing the need for manual adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If internally threaded sleeves are used to allow free rotation of bars, then rotational freedom is improved, but maintaining rotational and axial restraint becomes difficult requiring workers to ascend the structure

Engineering Contradiction:

Improverotational freedomVSAvoidmaintaining rotational and axial restraint

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The connection system is divided into two functional segments: the internally threaded sleeve that provides rotational freedom and the lock nut that provides axial restraint. This segmentation allows each component to perform its specific function independently, resolving the contradiction between rotational freedom and restraint maintenance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lock nut acts as an intermediary element between the internally threaded sleeve and the bar end. It mediates the conflicting requirements by allowing the bar to rotate freely within the sleeve while providing the necessary axial restraint through threading engagement, eliminating the need for workers to ascend the structure for adjustments.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If lock nuts are used to provide rotational and axial restraint, then stability is improved, but bar rotation causes loosening of clamping action requiring restoration at elevated heights

Engineering Contradiction:

Improverotational and axial restraintVSAvoidrestoring locks at elevated heights

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The axial restraint function is extracted from the lock nut and separated from the rotational freedom function provided by the internally threaded sleeve. This allows the lock nut to focus solely on providing stable axial restraint without interfering with bar rotation, while the sleeve handles rotational freedom, eliminating the loosening problem and the need for restoration at elevated heights.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using the lock nut to clamp the bar against the sleeve (which causes loosening during rotation), the solution inverts the approach by having the lock nut thread onto the bar end and engage with the sleeve's internal threads. This inverted configuration maintains stable restraint during rotation, preventing the loosening issue that requires restoration at elevated heights.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If threading or spinning bars into internally threaded sleeves is used, then rotational and axial restraint is achieved, but fabrication time and effort increase requiring temporary supports and rotating tools

Engineering Contradiction:

Improverotational and axial restraintVSAvoidfabrication time and effort

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The internally threaded sleeve is pre-installed on the cage frame assembly before bar installation. This preliminary action eliminates the need for temporary supports during bar insertion and reduces fabrication time, as workers simply need to insert the bar through the pre-positioned sleeve and secure it with a lock nut, rather than threading or spinning the bar into the sleeve.

Inventive Principle:

Principle #10Preliminary action

4Ease of manufacture

If more space is allocated for fabrication to accommodate threading operations, then assembly is simplified, but site space requirements and costs increase

Engineering Contradiction:

Improveassembly simplicityVSAvoidfabrication space

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The internally threaded sleeve is pre-installed on the cage frame assembly in a compact configuration before bar insertion. This preliminary action allows the assembly to be completed in a smaller fabrication space without requiring the extensive room needed for threading or spinning operations, while still achieving the same assembly simplicity and structural integrity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10041252B1Bar sleeve

Publication Date: 2018.08.07 BONGIORNO STEVEN JAMES

AI summary

A sleeve lock locks concrete reinforcing steel bars within rigid support structure retainers for stabilizing the reinforcing bars in place, while allowing the bars to spin freely within sleeves or holes within the retainers. The sleeve locks are stable couplings holding concrete reinforcing bars in position while allowing the bars to spin within the couplings. This reduces the need for tightening locks or fasteners at elevated heights of vertically positioned concrete reinforcing steel bars.