Slip Dowel Sheath and Coupler for Precise Cold Joint Alignment
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Solution Overview
Problem
Existing methods for placing slip dowels in concrete slabs are labor-intensive, costly, and often result in improper alignment, leading to cracking and faulting at cold joints, while prior art devices are limited in application and costly to manufacture.
Innovation Solution
A concrete dowel placement system comprising a coupler with tubular elements and a sheath that allows for easy, accurate placement of slip dowels, using extrusion to form components with varying dimensions and features for secure attachment to concrete forms, enabling parallel alignment and smooth slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional drilling and manual placement methods are used for slip dowels, then flexibility in installation is maintained, but labor intensity increases and alignment precision deteriorates
Solution Approach 1:
The system performs preliminary alignment by attaching the sheath to the concrete form before pouring concrete. The sheath pre-defines the exact position and orientation of the slip dowel, eliminating the need for post-pour drilling and alignment adjustments. This preliminary positioning action ensures precise parallel alignment while simplifying the overall installation process.
Solution Approach 2:
The sheath acts as an intermediary device between the concrete form and the slip dowel. It provides a guided pathway that ensures precise dowel placement while allowing easy attachment and removal. The sheath mediates the complex alignment requirements by providing a simple, pre-positioned template that guides dowel insertion.
2Reliability
If slip dowels are improperly positioned, then installation speed may be maintained, but structural reliability deteriorates due to cracking and faulting
Solution Approach 1:
The sheath provides localized precision at the critical cold joint interface by defining the exact position and orientation of each slip dowel. This local quality control ensures that dowels are perfectly parallel and properly positioned where it matters most - at the interface between concrete sections - thereby ensuring cold joint integrity without requiring precision throughout the entire construction process.
Solution Approach 2:
The system replaces manual measurement and alignment mechanisms with a pre-fabricated sheath structure that inherently provides the correct geometry. Instead of relying on workers to mechanically measure and align dowels, the sheath's physical structure substitutes for these complex mechanical alignment processes, ensuring consistent precision.
3Device complexity
If multiple separate components are used for dowel placement, then adaptability increases, but device complexity increases and manufacturing cost rises
Solution Approach 1:
The system merges the alignment template, positioning guide, and dowel holder functions into a single integrated sheath component. This consolidation reduces the number of separate parts needed while maintaining full functionality. The sheath combines multiple features that would traditionally require separate devices, thereby reducing complexity without sacrificing adaptability.
Solution Approach 2:
The sheath is designed as a universal component that can accommodate different dowel sizes and configurations while providing the same core functions of alignment, positioning, and guidance. This multi-functionality allows a single component design to serve multiple purposes and adapt to various application requirements without requiring multiple specialized parts.
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 system facilitates cost-effective and precise dowel placement, preventing buckling, bulging, and cracking at cold joints by allowing slip dowels to slide freely, maintaining structural integrity and aesthetic alignment.
Implementation Method 1
a sheath having an interior opening extending along the entire length of the sheath and being slidably extensible over the coupler to frictionally engage one of the first tubular element and the second tubular element
Data Source
AI summary
A concrete dowel placement system and methods for making the same. The system allows for accurate and easy substantially-parallel or parallel placement of slip dowels within sections of concrete so that adjacent sections of concrete may be allowed to undergo thermal expansion and contraction while remaining in a common plane without cracking or faulting. The system includes a coupler and a sheath. The sheath is configured to be slidably extensible over the coupler and may be held to the coupler by friction. Additionally, a method of constructing the concrete dowel placement system includes extruding material to form two tubes of different sizes. The tubes are then attached to each other, then material is extruded to form a sheath. Alternatively, construction may include extruding material to form a tube, then removing some of the material from the tube in order to form a coupler.