Anti-Creep Ring Captive Screw Alignment Mechanism
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Solution Overview
Problem
Securing a cap screw to an element while maintaining alignment and stability is challenging due to the difficulty in holding multiple components during screwing, particularly in applications like automotive engineering where cables need to be attached to cable stops.
Innovation Solution
An anti-creep ring with features that allow it to act as both a captive screw and a stop, featuring a design with projections and a slot for elastic deformation, enabling it to trap a conventional screw with a threaded portion larger than the shank diameter, allowing limited movement and coaxial alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional screw is used with a threaded portion larger than the shank diameter, then the screw can be easily manufactured and obtained, but it is difficult to hold and position the screw correctly during assembly
Solution Approach 1:
The anti-creep ring serves as an intermediary component between the screw and the element. It provides a positioning interface with its circular area that matches the screw's threaded portion diameter, enabling correct alignment and positioning during assembly while the screw itself remains a standard conventional design
Solution Approach 2:
The solution segments the positioning function from the screw itself by introducing a separate anti-creep ring component. The ring handles the positioning and alignment tasks while the screw focuses on its fastening function, resolving the difficulty of holding and positioning the screw during assembly
2Ease of operation
If the screw is made a captive component of the element, then alignment and positioning are improved, but the screw movement is overly constrained
Solution Approach 1:
The anti-creep ring provides localized constraint only where needed - the circular area constrains the threaded portion for positioning, while the smaller circular area allows the shank to move freely. This selective constraint achieves alignment without overly restricting screw movement
Solution Approach 2:
The ring transitions from a fully constrained captive screw design to a dynamic system where the screw can move within permitted ranges. The differential circular areas create zones of constraint and freedom, allowing the screw to adjust position while maintaining alignment
3Reliability
If the anti-creep ring is engaged in the recess, then the screw is trapped and retained, but the ring must undergo elastic deformation which complicates the design
Solution Approach 1:
The ring's diameter parameter is made variable through elastic deformation. The slot introduces flexibility allowing the ring to change its diameter temporarily during installation, then maintain a constrained state for screw retention, achieving reliability without permanent complex structures
4Reliability
If a special design captive screw is used, then the screw can be secured to the element, but the cost increases significantly
Solution Approach 1:
The anti-creep ring serves multiple functions: it acts as a captive screw holder, provides positioning alignment, prevents creep, and enables retention. By making one component multi-functional, the need for special expensive captive screws is eliminated while maintaining reliable screw securing
Solution Approach 2:
The invention merges the anti-creep function with the captive screw retention function into a single ring component. This consolidation achieves reliable screw securing without requiring specially designed expensive captive screws, reducing production costs
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 anti-creep ring effectively retains the screw as a captive component, simplifying the attachment process by performing dual functions, ensuring secure alignment and easy assembly in various industrial applications.
Implementation Method 1
said ring has features suitable for allowing elastic deformation as a result of the ring being engaged in the recess of the element, said deformation corresponding to a reduction in the diameter of the circular area
Data Source
AI summary
The cap screw (1) has a threaded portion (1b) having a nominal diameter (D1) that is greater than the diameter (D3) of its shank. The device comprises an anti-creep ring (4) designed to receive screw (1), one end of which has features (4a-4b-4c-4d) suitable for delineating, before ring (4) is engaged in a recess (2a) of element (2) that is to be screw fastened, a circular area having a diameter (D) that is greater than the nominal diameter (D1) of threaded portion (1b) and, after said ring (4) has been engaged in said recess (2a), a circular area (D) having a diameter (D2) that is less than the nominal diameter (D1) of threaded portion (1b), but greater than the diameter (D3) of shank (1a), so as to act as a stop for said threaded portion and trap screw (1) in ring (4) while permitting limited movement of the screw.