Integrated Door Latch Assembly for Hands-Free Medical Access

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Solution Overview

Problem

Conventional medical device treatment systems face challenges such as contamination from manual door/lid operation, complex and expensive mechanisms, inadequate door opening time, and excessive force leading to component damage, particularly in smaller systems.

Innovation Solution

A single mechanism integrating automatic and manual door opening with a latch and lock assembly, featuring a hands-free foot-operated control and forced-entry prevention, adjustable to handle manufacturing tolerances and maintain functionality throughout its life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two or more independent mechanisms are used to control door latching, locking, opening or closing, then the door can be securely latched and locked, but the assembly becomes complex and expensive and too large for smaller WDS

Engineering Contradiction:
Improvedoor latching and locking securityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines latching, locking, and opening functions into a single integrated mechanism. The door latch assembly includes a latch member with a latch arm that can be positioned in latched, unlocked, and locked states, eliminating the need for separate mechanisms and reducing overall system complexity while maintaining security.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The latch member serves multiple functions: it can latch the door closed, unlock to allow opening, and lock to prevent opening during sterilization cycles. This multi-functional design replaces what would traditionally require multiple separate mechanisms, reducing complexity while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Speed

If automatic door opening mechanism operates immediately upon activation, then door opening is fast, but operators do not have enough time to step back and allow space for the door to open

Engineering Contradiction:
Improvedoor opening speedVSAvoidoperator safety
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The controller is configured to unlock the door latch assembly before automatically opening the door. This preliminary unlocking action allows operators time to step back to a safe position before the door begins to move, eliminating the safety hazard of immediate door opening while maintaining fast overall operation.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If open hook grab latches are used, then the door can be easily opened, but excessive downward force can overcome the latch and impart undue stress on fragile components

Engineering Contradiction:
Improvedoor opening easeVSAvoidlatch mechanism strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The latch member is designed to dynamically transition between latched, unlocked, and locked states. When locked, it provides strong resistance to excessive force; when unlocked, it allows easy manual opening. This dynamic state change capability maintains both strength and ease of operation.

Inventive Principle:
Principle #15Dynamics

4Force

If heavy-duty stronger mechanism components and door hinges are used, then the amount of force required to overcome latches increases beyond operator capability, but the components are too large for smaller WDS

Engineering Contradiction:
Improveforce resistanceVSAvoidcomponent size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The door latch assembly is segmented into distinct functional components: a latch member with latch arm, a locking member, and a controller. This segmentation allows each component to be optimized for its specific function while keeping individual component sizes small enough for compact WDS installations.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4455430B1Door latch, lock and open mechanism for medical device treatment system
Publication Date: 2025.11.12 AMERICAN STERILIZER CO
  • EP4455430B1 patent drawingFigure 1a~1b
  • EP4455430B1 patent drawingFigure 2
  • EP4455430B1 patent drawingFigure 3

AI summary

A latch and lock assembly includes a lever pivotable between a latched and unlatched position. A first actuator selectively moves a locking tab between a locked and unlocked position. In the locked position, the locking tab blocks pivotable movement of the lever from the latched position to the unlatched position. In the unlocked position, the locking tab allows pivotable movement of the lever from the latched position to the unlatched position. A second actuator selectively rotates a door opening tab between a first and second position when the locking tab is in the unlocked position is included. When the door opening tab is in the first position the lever is in a latched position, and when the door opening tab is rotated from the first position to the second position, the door opening tab abuts the lever and urges the lever from the latched position to the unlatched position.