Split Bushing for Long-Stem Screw Fastening
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Solution Overview
Problem
Existing fastening devices face challenges in securely attaching screws with long stems to objects without increasing the size or complexity of the eyelet, particularly when using screws that need to pass through a clearance hole, leading to high manufacturing costs and complexity.
Innovation Solution
A fastening device with a base and connection eyelet featuring a bushing composed of two separate parts that can be inserted around the screw stem, allowing the screw head to pass through and providing sufficient clearance for rotation, enabling the use of ordinary screws without altering the eyelet's size or shape, and incorporating a snap ring for secure assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-piece bushing is used to secure the screw, then the manufacturing is simple, but the screw head cannot pass through the opening when the screw has a long stem
Solution Approach 1:
The bushing is divided into two separate half-bushings that can be assembled around the screw stem after the screw head passes through the opening. This segmentation allows the opening to accommodate long-stemmed screws while maintaining a simple manufacturing process for the bushing components.
2Length of moving object
If the opening size is increased to accommodate long-stemmed screws, then the screw can be inserted, but the eyelet size increases leading to increased bulk, weight and costs
Solution Approach 1:
The two half-bushings are designed to nest around the screw stem, with one half-bushing fitting over the other. This nested configuration allows the bushing assembly to fit within the existing opening dimensions without requiring an enlarged opening, thereby maintaining the original eyelet size, weight, and cost characteristics.
3Reliability
If a special shaped nut with flange is used to fix the screw, then the screw can be secured, but the overall costs and complexity increase
Solution Approach 1:
The bushing assembly serves multiple functions: it acts as a bearing surface for the screw head, provides a retaining flange structure, and enables the eyelet to rotate about the screw axis. By making the bushing multi-functional, the need for separate specialized components like shaped nuts with flanges is eliminated, reducing overall device complexity and cost.
4Length of moving object
If the screw is inserted from the extremity opposite to the head, then long-stemmed screws can be used, but a specially shaped nut is required increasing costs
Solution Approach 1:
Instead of inserting the screw from the opposite extremity and using a special nut to secure it, the invention inverts the approach by having the screw head pass through the opening first, then assembling the split bushing around the stem. This reversal eliminates the need for specially shaped nuts while still accommodating long-stemmed screws.
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
Enables the secure attachment of screws with long stems to objects using commercial screws, simplifying manufacturing and reducing costs while maintaining the eyelet's compact design and allowing for rotation to adapt to load directions, enhancing safety and load-bearing capacity.
Implementation Method 1
said bushing being adapted to be compressed between the head of the screw and a surface of said object
Data Source
Figure 1~2
Figure 3
AI summary
A fastening device comprising: a fastening element (5) which comprises a connection eyelet (4) and a base (3), integral therewith, having an opening (7) adapted to accommodate a screw; a screw (1) adapted to secure said element to an object to be lifted or lashed; a bushing (2) adapted to be accommodated into said opening and to be interposed between said screw and said base, said bushing being adapted to be compressed between the head (8) of the screw and a surface of said object and having a portion (10), capable of retaining said base to the object, when the screw is screwed into said object; characterised in that said opening has dimensions allowing the head of the screw to pass through it and the bushing is composed of at least two separate parts, capable of being inserted into said opening around the stem of the screw when said screw is present in said opening so that said portion is interposed between the head of the screw and the base.