Overmolded Flashlight Grip Recess Design

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Solution Overview

Problem

Existing flashlight grips, such as knurled aluminum and rubber sleeves, face issues with slipperiness, comfort, and durability, with rubber grips often becoming loose and falling off over time.

Innovation Solution

The implementation of overmolded grips on a metal flashlight shaft with a circumferential grip recess bounded by raised portions, where the grip is integrally formed as a single piece and molded directly onto the shaft, using a polymer material insufficiently flexible to pass over the raised portions without damage, ensuring a secure and comfortable hold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rubber sleeve grip is added to the flashlight body, then grip comfort is improved, but the grip may become loose and fall off over time

Engineering Contradiction:

Improvegrip comfortVSAvoidgrip retention

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The grip and flashlight body are merged into a single integrated structure through overmolding. The polymeric grip material is molded directly onto the metal shaft, creating a permanent bond that eliminates the risk of the grip becoming loose or detached, while maintaining ergonomic comfort.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The flashlight combines two different materials - a metal shaft and a polymeric grip material - into a composite structure. This allows the metal shaft to provide structural strength while the polymeric material provides grip comfort and non-slip properties, with the overmolding process ensuring permanent attachment.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If knurling is applied to the flashlight body, then surface friction is improved, but aesthetic appearance deteriorates

Engineering Contradiction:

Improvesurface frictionVSAvoidaesthetic appearance

Core Design Contradiction:

Ease of operationVSShape

Solution Approach 1:

The polymeric grip material is applied locally to the specific region where grip is needed, rather than treating the entire flashlight body. This allows the metal shaft to maintain its smooth, aesthetic appearance while the polymeric portion provides enhanced friction and comfort in the hand-held area.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If a flexible grip material is used, then grip comfort is improved, but the material can be damaged when passing over raised portions

Engineering Contradiction:

Improvegrip comfortVSAvoidmaterial integrity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The grip material is molded onto the shaft in its final position before any potential damage could occur. The overmolding process forms the grip directly on the shaft with the raised portions already in place, eliminating the need to stretch or force the material over these features, which would cause damage.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11162647B2Flashlight with overmolded grip and methods of manufacture

Publication Date: 2021.11.02 SIMPLE PRODUCTS CORP

AI summary

A flashlight can include a flashlight shaft, a grip overmolded on the flashlight shaft, and a light element connected to the flashlight shaft. The flashlight shaft can have a circumferential grip recess bounded by two raised portions. The grip recess can have a surface lower than the two raised portions around a circumference of the shaft. The shaft can be integrally formed as a single piece. The grip can be overmolded into the grip recess, such that the grip covers the surface of the grip recess and is bounded by the two raised portions. The grip can be formed of a material that is insufficiently flexible to pass over the two raised portions without damage.