Magnet Cap With Wings For Secure Plastic Attachment

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Solution Overview

Problem

In high-volume manufacturing of telecommunications devices, heat-staking magnets directly to plastic parts often results in inconsistent location and dimensional tolerances, and the difference in coefficients of expansion can cause the magnet to rattle or become loose, leading to insecure attachment.

Innovation Solution

A method involving a magnet cap with wings and a bucket with stepped grooves, where the cap is joined to the bucket using thermoplastic materials, creating an assembly that encapsulates the magnet with ribs for secure engagement, allowing for consistent and strong attachment through various staking processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If heat staking is used to join magnets directly to plastic parts, then the joining process is simple and fast, but the location and dimensional tolerances become inconsistent

Engineering Contradiction:

Improvejoining speedVSAvoidlocation and dimensional tolerances

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention divides the joining system into three separate components: a bucket (mold cavity), a magnet holder (recess), and a cap. This segmentation allows each component to be precisely manufactured and assembled, improving overall positioning accuracy while maintaining production efficiency through modular assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The magnet holder acts as an intermediary component between the bucket and the cap, providing a stable platform for magnet placement. This intermediate structure ensures consistent magnet positioning and dimensional tolerances that cannot be achieved through direct heat staking alone.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If magnets are secured in a conventional housing with heat staking, then the joining process is simple, but the magnet becomes easily broken loose due to coefficient of expansion differences

Engineering Contradiction:

Improvejoining process simplicityVSAvoidmagnet attachment security

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention uses a composite structure combining plastic (bucket and cap) with metal or other non-plastic materials (magnet holder and magnet). This composite design accommodates different coefficients of thermal expansion for each material, preventing the magnet from becoming loose while maintaining manufacturing simplicity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Instead of directly heating and staking the magnet to the plastic part (conventional approach), the invention inverts the process by first forming the magnet holder recess, then placing the magnet, and finally joining the cap to the bucket. This inverted sequence improves reliability by ensuring proper magnet seating before the final joining operation.

Inventive Principle:

Principle #13The other way round (Inversion)

3Productivity

If direct heat staking is used to join magnets to plastic parts, then the process is fast, but the magnet may rattle within the enclosure due to expansion differences

Engineering Contradiction:

Improvemanufacturing cycle timeVSAvoidmagnet position stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The magnet holder recess is formed in advance within the bucket, providing a pre-positioned cavity that precisely fits the magnet. This preliminary action ensures the magnet is correctly positioned before the cap is attached, preventing rattling while maintaining fast production cycle times.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The magnet is nested within the magnet holder recess, which is itself nested within the bucket structure. This nested arrangement provides multiple levels of positioning constraint, ensuring the magnet remains stable and does not rattle, while the modular design maintains manufacturing efficiency.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 provides greater dimensional consistency and a secure attachment of magnets to plastic parts, preventing rattling and extending the product's lifespan by ensuring accurate and reliable joining in high-volume manufacturing.

Implementation Method 1

heat-staking a magnet directly to a plastic part

Methodology Applied

Scientific EffectHeat staking: Heating

Implementation Method 2

the difference between the coefficients of expansion of the magnet and the plastic

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

The cap may be joined to the bucket by ultrasonic welding

Methodology Applied

Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentUS7986206B2Magnet cap

Publication Date: 2011.07.26 AVAYA INC

AI summary

One or more method(s), system(s), and/or device(s) produces an assembly for securing a product to a dissimilar material, such as a magnet to plastic. A magnet assembly may include a plastic cap having one or more wings extending laterally from a side surface of the plastic cap. A plastic holder defines a product cavity and has one or more grooves formed to integrally fit with the one or more wings of the plastic cap. A magnet is positioned within the product cavity. The plastic cap is joined to the plastic holder, such as through staking or welding, to capture the magnet within the product cavity.