Folding Rule Snap-Fit End Cap Design
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Solution Overview
Problem
Existing folding rules face challenges in protecting their free end portions from damage, especially when made of plastic, as previous solutions require complex assembly methods and precise fastening that can introduce measurement errors.
Innovation Solution
A folding rule with a protective end cap featuring a snap-fit engagement mechanism, where a U- or C-shaped end cap with a protrusion and recess system securely covers the free end portion, allowing for easy assembly and minimizing manufacturing complexity while ensuring accurate positioning to prevent measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal spikes or rivets are used to fix the protective end piece to plastic folding rule members, then the protective end piece can be securely fastened, but the assembly process becomes complex and difficult to manufacture
Solution Approach 1:
The patent replaces complex mechanical fastening systems (metal spikes, rivets, welding) with a simple snap-fit engagement mechanism. The protective end piece features a geometric shape that automatically engages with the end member through elastic deformation and geometric interlocking, eliminating the need for additional fasteners or complex assembly processes while maintaining secure attachment
Solution Approach 2:
The protective end piece is designed to self-align and self-fasten through its geometric shape and elastic properties. During assembly, the end piece automatically deforms to engage with the end member and then snaps into place without requiring external fastening operations, making the assembly process as simple as pressing the components together
2Reliability
If welding is used to secure the end piece to the folding rule, then the protective end piece can be firmly attached, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The patent replaces thermal welding processes with a mechanical snap-fit engagement system. The protective end piece uses elastic deformation and geometric interlocking to achieve firm attachment without heat application, significantly reducing assembly time and eliminating the complexity of welding equipment and processes
3Reliability
If hooks or holding means are provided inside the end member to secure the protective piece, then the protective end piece can be firmly fastened, but the end member design becomes complex and requires extensive cutouts
Solution Approach 1:
Instead of providing holding means (hooks, recesses) inside the end member, the patent inverts the approach by providing the engagement features directly on the protective end piece itself. The geometric shape and elastic properties of the end piece create the fastening mechanism, simplifying the end member design to a basic supporting structure without internal cutouts or features
4Manufacturing precision
If the protective end cap is precisely matched to the engagement portion, then accurate positioning is achieved, but manufacturing tolerance requirements increase and assembly becomes more difficult
Solution Approach 1:
The patent uses elastic deformation as a parameter change mechanism to accommodate manufacturing tolerances. The protective end piece is designed with elastic properties that allow it to deform during assembly, enabling it to engage with the end member even when there are slight variations in dimensions. The elastic recovery then provides precise positioning after assembly
Solution Approach 2:
The patent introduces dynamic behavior through elastic deformation, allowing the protective end piece to adapt its shape during assembly. This dynamic capability enables the component to accommodate tolerance variations and self-align with the end member, achieving accurate positioning without requiring extremely tight manufacturing tolerances
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 snap-fit engagement system provides robust protection for the free end portion, simplifies the manufacturing process, and ensures precise alignment to prevent measurement faults, enhancing the durability and accuracy of the folding rule.
Implementation Method 1
a protrusion (7) in snap-fit engagement with a corresponding recess (8) in the end member (2)
Data Source
Figure 1
Figure 2~3a
Figure 3b~3c
AI summary
The present invention relates to a folding rule and to a protective end cap for a folding rule. The folding rule (1) comprises an end member (2) with a first end portion (3) and a second end portion (4) opposite the first end portion, wherein said the first end portion is linked to another member (5) of the folding rule and the second end portion is provided with a protective end cap (6), wherein the protective end cap includes a protrusion (7) in snap-fit engagement with a corresponding engagement portion (8) of a first outer surface (12) of the end member so as to prevent the protective end cap from sliding off the end member.