Ladder Cable Tray Radially Expandable Fastener Assembly
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Solution Overview
Problem
Conventional ladder-type cable trays face challenges in securely fastening rungs to side rails without the use of welding or screws, which can lead to instability and issues with cable support in the construction industry.
Innovation Solution
The use of radially expandable fasteners, such as blind rivets, with inwardly extending fastener openings and projections on the rungs, provides a secure and frictional engagement to inhibit withdrawal, allowing for a strong and stable connection between the rungs and side rails without the need for welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding or screws are used to secure rungs to rails, then the connection strength is improved, but the manufacturing complexity and time increase
Solution Approach 1:
The fastening system is divided into separate modular components: the rung with integrated fastener openings and the insert fasteners. This segmentation allows each component to be manufactured independently through extrusion, eliminating complex welding or screw-assembly processes while maintaining connection strength through the friction-fit mechanism.
Solution Approach 2:
The rungs are designed with self-contained fastener openings that directly receive and secure the insert fasteners without requiring external fastening elements like screws or welds. The system is self-sufficient, with the rung structure itself providing the fastening mechanism, thereby reducing manufacturing complexity.
2Strength
If welding is used to secure rungs to rails, then the structural integrity is improved, but the assembly time and productivity decrease
Solution Approach 1:
The fastener openings are pre-formed into the rung structure during extrusion, and the insert fasteners are pre-positioned within these openings. This preliminary preparation eliminates the need for time-consuming welding operations during final assembly, thereby improving productivity while maintaining structural integrity through the pre-engineered friction-fit connection.
3Ease of manufacture
If conventional fastening methods are used, then the ease of manufacture is improved, but the reliability of the connection deteriorates
Solution Approach 1:
The connection reliability is enhanced by changing the fastening parameter from mechanical (screws) or thermal (welding) to friction-based radial expansion. The insert fasteners expand radially within the fastener openings to create a friction fit, providing reliable connections that are easier to manufacture through extrusion processes.
4Reliability
If radially expandable fasteners are used, then the connection reliability is improved, but the device complexity increases
Solution Approach 1:
The fastener system merges multiple functions into a single integrated component: the insert fastener combines the fastening element with the radial expansion mechanism. This merging reduces the number of separate parts and simplifies the overall assembly process, making the device less complex while maintaining high connection reliability through the friction-fit mechanism.
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 enhances the stability and ease of assembly of cable trays by providing a secure fastening mechanism that prevents withdrawal of fasteners, eliminating the need for welding and ensuring consistent connections, thus improving the structural integrity and manufacturing efficiency.
Implementation Method 1
Each radially expandable portion is in an expanded configuration and frictionally engages the corresponding rung inside the corresponding fastener opening to inhibit withdrawal of the radially expandable fastener from the fastener opening.
Data Source
AI summary
A cable tray includes a plurality of fasteners fastening rungs to side rails. Each fastener may be a radially expandable fastener having a radially expandable portion received in one of the fastener openings of one of the rungs. Each radially expandable portion is in an expanded configuration and frictionally engages the corresponding rung inside the corresponding fastener opening to inhibit withdrawal of the radially expandable fastener from the fastener opening. Each fastener opening may be defined by an interior surface of the corresponding rung and at least one projection extending radially inward from the interior surface relative to the fastener opening. The fastener may have an engagement portion frictionally engaging the corresponding at least one projection inside the corresponding fastener opening to inhibit withdrawal of the radially expandable fastener from the corresponding fastener opening.