Movable Strap Flip-Flop to Sandal Conversion

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Solution Overview

Problem

Existing flip-flop designs lack the ability to convert into a more secure sandal with additional support for the bridge and upper ankle of the foot.

Innovation Solution

A flip-flop shoe with a movable horizontal strap embedded within a recess in the heel section of the sole, allowing the strap to be raised to cover the bridge and upper ankle, converting the flip-flop into a sandal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a flip-flop is designed with only a toe strap, then it provides simplicity and ease of wear, but it lacks adequate support and security for the bridge and upper ankle of the foot

Engineering Contradiction:

Improveease of wearVSAvoidfoot support and security

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The horizontal strap is designed to be movable between a stored position within the recess and an extended position across the foot, allowing the footwear to dynamically adapt between flip-flop and sandal configurations based on support needs

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The footwear structure serves multiple functions: it can function as a simple flip-flop with the strap stored in the recess, or as a supportive sandal with the strap extended across the bridge and upper ankle, providing versatility in a single design

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If additional straps are added to provide foot support, then foot support and security are improved, but the device complexity increases

Engineering Contradiction:

Improvefoot support and securityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The horizontal strap is nested within a recess in the sole when not in use, allowing the support structure to be concealed and integrated into the footwear body, thereby providing support functionality without permanently increasing visual or structural complexity

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The horizontal strap can be extracted or moved from its stored position in the recess to its functional position across the foot, allowing the support element to be deployed only when needed rather than being permanently exposed

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentEP3967173B1Flip-flop capable of changing to a sandal having an embedded rear strap movable between two positions

Publication Date: 2025.03.05 FLIPSANDAL LICENSING LLC

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AI summary

The present invention provides footwear capable of changing between a flip-flop and a sandal. The structure of a flip-flop which includes a sole having a top section, a bottom section, a forefoot section, a heel section, and a sidewall section. Also, a forefoot cover having V-shaped straps is positioned and extends over at least a part of the forefoot section and is attached to the top section of the sole. A horizontal recess is formed in the heel section of the sole for receiving therein a horizontal strap, which is removably placed in the horizontal recess. The horizontal strap is moveable by the user between a first stored position in the recess, and a second in-use raised position, wherein the horizontal strap extends above the horizontal recess and covers the bridge of the user's foot in order to convert the flip-flop to a sandal for securing the foot more securely.