Bathroom Transfer System Chair Blocking for Secure Bridge Connection

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Solution Overview

Problem

Existing transfer systems for disabled persons to access bathroom facilities lack a safety mechanism that prevents the slidable translation of the upper chassis onto a removable connector bridge unless both ends of the connection are securely attached, posing a risk of severe injury if the connection is not properly secured.

Innovation Solution

A transfer system with a chair blocking member and latch members that ensure the removable bridge can only be moved between a mobile and stationary base when both latches are securely engaged, preventing unauthorized movement and ensuring safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the removable connector bridge is designed to connect only at one end, then the device complexity is reduced, but the reliability of the transfer system deteriorates because the chair can slide off the bridge

Engineering Contradiction:
Improveconnector bridge structureVSAvoidtransfer system safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The connector bridge is divided into a removable portion and a fixed portion, with the removable portion designed to connect to both the mobile base and stationary base through separate latch mechanisms. This segmentation allows the bridge to be assembled in sections while maintaining overall structural integrity and safety.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The latch members are designed to automatically engage with the mobile base and stationary base before the chair is positioned on the bridge. This preliminary securing action ensures that both ends of the removable connector bridge are firmly attached before use, preventing the chair from sliding off during transfer.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If latch members are added to secure both ends of the removable bridge, then the reliability improves, but the device complexity increases

Engineering Contradiction:
Improveconnection securityVSAvoidlatch mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The latch members are designed to be self-latching, automatically engaging with the mobile base and stationary base when the removable connector bridge is properly positioned. This self-service mechanism eliminates the need for manual securing operations while ensuring reliable connection at both ends.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The latch mechanism replaces complex mechanical fastening systems with simpler engagement features that rely on basic mechanical principles such as hooks, latches, or snap-fit connections. This substitution maintains connection security while reducing overall device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the chair blocking member is always in the unblocked position, then the ease of operation improves, but the safety deteriorates because the chair can move onto the bridge when not properly secured

Engineering Contradiction:
Improvechair movement freedomVSAvoidchair sliding risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The chair blocking member is designed to dynamically change position based on the security status of the latch members. When latches are engaged, the blocking member automatically moves to an unblocked position allowing chair movement. When latches are disengaged, the blocking member moves to a blocked position preventing chair movement, thus adapting to system conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The blocking member is mechanically linked to the latch members, creating a feedback mechanism where the latching status directly controls the blocking status. This feedback ensures that the chair can only move when the system is in a safe state with both ends properly secured, eliminating the need for manual safety checks.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4014940B1Safety system for a bathroom facility transfer system
Publication Date: 2026.02.25 RAZ DESIGN INC
  • EP4014940B1 patent drawingFigure 1~2
  • EP4014940B1 patent drawingFigure 3~6
  • EP4014940B1 patent drawingFigure 7~8

AI summary

A bathroom facility transfer system, including a mobile base, a stationary base, and a removable bridge is disclosed. A user seated in a chair, is positioned adjacent to a bathroom facility with the mobile base. The removable bridge connects the mobile base to the stationary base, which is removably affixed to the bathroom facility, to allow the chair carrying the user to be moved between the mobile base and the stationary base. A chair blocking member on the removable base is movable between a) a chair blocking position, and b) a chair unblocking position. At least one opposed end of the chair blocking member interferes with movement of the chair onto the removable bridge from the mobile base or the stationary base, when the chair blocking member is in the chair blocking position. A method of assisting a user with accessing a bathroom facility is also disclosed.