Core for armrest

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Solution Overview

Problem

Resin-based armrest cores face challenges in providing high resistance to loads, especially when equipped with a stopper pin, as they tend to lack the necessary strength and stability compared to metal cores.

Innovation Solution

A resin-based core with a metal stopper pin subjected to insert molding, featuring a rib structure that overlaps with the stopper pin's base-end face, providing enhanced load resistance and preventing the pin from coming off, while maintaining a lightweight design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a resin-based core is used for the armrest, then the armrest becomes lightweight, but the resistance to loads at portions around the stopper pin is insufficient

Engineering Contradiction:
Improveweight of armrest coreVSAvoidresistance to loads at stopper pin portions
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent applies composite materials by combining resin and metal in a single integrated core structure. The framed body is made of resin while the stopper pin is made of metal, creating a composite component that leverages the lightweight properties of resin and the high strength of metal at critical load-bearing locations.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements local quality by using different materials for different portions of the core. The resin is used for the framed body where weight reduction is prioritized, while metal is used specifically for the stopper pin where high load resistance is required. This localized material selection optimizes both weight and strength requirements.

Inventive Principle:
Principle #3Local quality

2Strength

If a metal stopper pin is inserted into a resin core, then the pin exhibits high resistance to loads, but the pin may come off from the resin body under high loads

Engineering Contradiction:
Improveresistance to loads of stopper pinVSAvoidretention of stopper pin in resin body
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies preliminary action by performing insert molding during the core manufacturing process. The metal stopper pin is inserted into the resin framed body before the resin fully cures, allowing the resin to flow around and mechanically interlock with the pin. This preliminary positioning ensures reliable retention before final assembly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the stopper pin and framed body into a single integrated component through insert molding. The metal pin and resin body are combined in one manufacturing step, creating a unified structure where the pin is permanently embedded in the resin, eliminating separate assembly steps and improving retention reliability.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the stopper pin is fixated onto the core after molding, then the pin can be positioned, but the connection strength is insufficient under high loads

Engineering Contradiction:
Improveprocessability of stopper pin installationVSAvoidconnection strength of stopper pin
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies preliminary action by performing insert molding during the core manufacturing process. The metal stopper pin is inserted into the resin framed body before the resin fully cures, allowing the resin to flow around and mechanically interlock with the pin. This preliminary positioning ensures reliable retention before final assembly.

Inventive Principle:
Principle #10Preliminary action

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 solution ensures high load resistance and secure retention of the stopper pin, even under heavy loads, by combining the strength of metal with the lightweight properties of resin, and the rib structure enhances the pin's stability within the core.

Implementation Method 1

a stopper pin being made of metal, the stopper pin being subjected to insert molding in the framed body

Methodology Applied
Scientific EffectInsert molding:

Implementation Method 2

a rib being integrally molded onto the framed body inside the framed body, and being disposed so as to overlap with respect to a base-end face of the stopper pin in an axial direction of the stopper pin

Methodology Applied
Scientific EffectMechanical interlocking:

Data Source

PatentEP2738038B1Core for armrest
Publication Date: 2019.05.08 TOKAI CHEMICAL INDUSTRIES LTD
  • EP2738038B1 patent drawingFigure 1~2
  • EP2738038B1 patent drawingFigure 3~4
  • EP2738038B1 patent drawingFigure 5~6

AI summary

To provide a core for armrest, the core including a stopper pin for restricting rotation, and exhibiting higher resistance to loads. A core (10) for armrest includes a framed body (20) being made of resin, a stopper pin (30) being made of metal, the stopper pin being subjected to insert molding in the framed body (20) so as to protrude a leading-end side thereof toward an outer side of the framed body (20), and being hooked onto a stopper (52) of a seat, thereby being restricted from rotating, and a rib (42) being integrally molded onto the framed body (20) inside the framed body (20), and being disposed so as to overlap with respect to a base-end face of the stopper pin (30) in an axial direction of the stopper pin (30).