Refillable Roll-On Bottle Thread Design to Prevent Disconnection

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Solution Overview

Problem

Existing roll-on bottles are discarded entirely when the product is finished, leading to environmental harm and unnecessary waste, and often suffer from poor assembly and disconnection issues during use.

Innovation Solution

A refillable roll-on bottle design with a conemorse mechanism, where the storage portion can be replaced, featuring distinct thread angles and forces to prevent simultaneous unscrewing of the lid and storage portion, allowing easy refilling and reuse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the entire roll-on bottle is discarded when the product finishes, then the user acquires a completely new bottle, but this causes environmental harm and waste of reusable components

Engineering Contradiction:
Improvesimplicity of bottle designVSAvoidwaste of reusable components
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The bottle is divided into separable components: a reusable applicator assembly (lid with applicator ball) and a replaceable storage portion (refill cartridge). This segmentation allows the storage portion to be replaced while retaining the applicator assembly, eliminating waste of reusable components while maintaining simple design principles.

Inventive Principle:
Principle #1Segmentation

2Loss of substance

If the bottle is designed to be refillable, then component reuse is enabled, but the assembly becomes difficult to use and components may disconnect during application

Engineering Contradiction:
Improvereduction of wasteVSAvoiduser convenience
Core Design Contradiction:
Loss of substanceVSEase of operation

Solution Approach 1:

Different thread configurations are applied to different connections: the connection between the lid and applicator assembly uses a standard thread for easy assembly/disassembly, while the connection between the storage portion and applicator assembly uses a conical thread (conemorse) that provides gradual engagement and secure locking. This local differentiation of thread qualities ensures both ease of operation and prevention of disconnection during use.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the lid is unscrewed with sufficient force to remove it, then the lid can be opened for use, but this may simultaneously cause disconnection of the storage portion

Engineering Contradiction:
Improveease of lid removalVSAvoidstability of assembly
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The conical thread (conemorse) configuration at the storage portion connection creates a self-locking mechanism where the conical geometry distributes the unscrewing force gradually along the threaded engagement. This local structural quality difference ensures that the storage portion remains securely connected even when sufficient force is applied to remove the lid, preventing accidental disconnection during normal operation.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4101338B1Refilling method and refillable bottle
Publication Date: 2026.04.08 NATURA COSMETICOS SA
  • EP4101338B1 patent drawingFigure 1
  • EP4101338B1 patent drawingFigure 2(a)~2(b)
  • EP4101338B1 patent drawingFigure 3A~3C

AI summary

The present invention refers to a refillable bottle (10) comprising a lid (1) connectable to an applicator (2), and a storage portion (3) connectable to the applicator (2), wherein the connection between the lid (1), applicator (2) and storage portion (3) occurs by means of the arrangement of threads on the lid (1), in the applicator (2) and in the storage portion (3). There is further described a method for refilling a bottle (10), said bottle (10) comprising a lid (1) connectable to an applicator (2) and a storage portion (3) connectable to the applicator (2), wherein the method comprises the steps of: disconnecting the storage portion (3) from the applicator (2) and by means of a first unscrewing action, and connecting a refill (20) to the applicator (2), wherein the force required to perform the first unscrewing action is greater than the force required to perform the second unscrewing action, said second unscrewing action being understood as the action performed to disconnect the lid (1) from the applicator (2).