Fastener Retainer Cavity Design for Damage-Free Alignment
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Solution Overview
Problem
Conventional fastener retainers, such as welded nuts and thin metal strips, often damage or lose fasteners, leading to increased costs and logistical burdens due to misalignment, breakage, and difficulty in attachment to mounting surfaces.
Innovation Solution
A retainer arrangement with a cylindrical cavity, internal dome step, and tapered entry, composed of thermoplastic or spring steel, that restricts fastener movement while allowing flexibility and snap-fit attachment to mounting surfaces, guiding fasteners without damaging them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is used to attach the nut to the work piece, then the nut is securely fixed and cannot move during assembly, but this introduces problems as the welding does not allow for any tolerances and the nut becomes immovable with respect to the work piece
Solution Approach 1:
The retainer arrangement separates the attachment function (projections attaching to mounting surface) from the fastener retention function (cylindrical cavity holding fastener), allowing each to be optimized independently. The projections can be designed for specific attachment methods while the cavity provides universal fastener retention with tolerance accommodation.
Solution Approach 2:
The retainer body is designed with flexible projections that can deform elastically during attachment, allowing the retainer to adapt to mounting surface variations and tolerances. This dynamic flexibility resolves the contradiction between secure attachment and tolerance adjustment.
2Ease of operation
If a thin metal strip is used as a retainer to guide the fastener, then the fastener can be guided during assembly, but this type of arrangement can sometimes damage the fastener or the threads of the fastener
Solution Approach 1:
The retainer body is made from a flexible material that can deform elastically, providing a soft guidance mechanism that accommodates fastener variations without causing damage. The flexible material absorbs misalignment stresses that would otherwise damage rigid thin metal strip retainers.
Solution Approach 2:
The retainer design changes the mechanical parameters of the guidance system by using elastic deformation capability and increased material thickness, transforming the rigid guidance mechanism into a compliant one that prevents fastener damage while maintaining guidance functionality.
3Reliability
If thin metal strip retainers are used to engage with the fastener, then the fastener can be retained, but these retainers are prone to breaking during shipping or assembly and may deform and lose functionality
Solution Approach 1:
The retainer is constructed from composite or reinforced material structure that combines flexibility with high strength and break resistance. This allows the retainer to maintain fastener retention capability while withstanding shipping and assembly stresses that would break thin metal strip retainers.
Solution Approach 2:
The retainer design incorporates inherent flexibility and deformation capacity to absorb and cushion against impact loads during shipping and assembly, preventing the breakage that occurs with rigid thin metal strip retainers subjected to the same stresses.
4Reliability
If additional means such as riveting or welding are used to attach the metal strip to a mounting surface, then the retainer can be securely attached, but this increases the complexity of the attachment process and may damage the mounting surface
Solution Approach 1:
The retainer features self-contained attachment projections that can be directly attached to mounting surfaces without requiring additional fastening operations. The projections are designed to engage with corresponding features on the mounting surface, making the retainer self-sufficient for attachment and eliminating the need for separate riveting or welding steps.
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 retainer arrangement ensures secure fastener alignment and easy attachment, reducing assembly time and costs by preventing fastener loss and damage, while allowing flexible installation and removal.
Implementation Method 1
a tapered entry at a second end of the cylindrical cavity
Implementation Method 2
an internal dome step at a first end of the cylindrical cavity
Implementation Method 3
The cylindrical cavity is smooth and aligns the fastener with an axis of the object
Implementation Method 4
the body is composed of a spring steel composition or elastic material
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A retainer arrangement for retaining and guiding a fastener to an object includes a body having an opening, a cylindrical cavity, and a pair of projections defining attachment elements for attaching to a mounting surface, the cylindrical cavity having an internal dome step at a first end of the cylindrical cavity and a tapered entry at a second end of the cylindrical cavity, wherein the fastener is received in the cylindrical cavity, and the opening being defined between the pair of projections.