Imaging Device Access Door Linkage for Low Closing Force

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Access doors for imaging devices require forces exceeding the 22.2 N limit to overcome spring biasing and engagement forces, friction, and other resistive forces, making them difficult for users with disabilities to open and close according to Section 508 accessibility standards.

Innovation Solution

A movable access door assembly with a linkage assembly, including a lower link connected via a first revolute joint and an upper link connected via a compound joint that transforms between prismatic and revolute joints, allowing the access door to move between closed, open, and raised positions with reduced force requirements, utilizing a four-bar linkage mechanism to facilitate opening and closing with less than 22.2 N of force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional spring-biased access door is used to engage customer replaceable units, then the door can securely hold CRUs, but the closing force exceeds the 22.2 N accessibility limit

Engineering Contradiction:

Improvesecure engagement of CRUsVSAvoidclosing force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent transforms the static hinge connection into a dynamic four-bar linkage mechanism with a transformable compound joint that changes its kinematic properties during operation. The joint transitions between prismatic and revolute configurations, dynamically adjusting the mechanical advantage to reduce closing force while maintaining secure engagement.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The compound joint changes its geometric parameters and kinematic characteristics during door operation. By transforming between different joint types (prismatic to revolute), the system alters its mechanical properties to optimize force reduction during the closing stroke while ensuring proper engagement.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If spring biasing forces are increased to ensure proper seating of CRUs, then engagement reliability improves, but the force required to open and close the door increases beyond accessibility limits

Engineering Contradiction:

Improveproper seating of CRUsVSAvoidease of door operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The four-bar linkage mechanism acts as an intermediary between the user and the spring-biased CRU engagement system. It transforms and amplifies the user's input force, mediating the interaction to overcome spring biasing forces without requiring the user to directly apply excessive force to the door.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The dynamic transformation of the compound joint creates a time-varying mechanical advantage that assists the user during door operation, making the system easier to operate while maintaining reliable CRU seating through the spring biasing.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If friction in hinges is reduced to ease door operation, then ease of operation improves, but the door may not maintain proper engagement position

Engineering Contradiction:

Improveease of door openingVSAvoidmaintenance of engagement position

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces the simple hinge friction mechanism with a sophisticated four-bar linkage system that uses geometric constraints and transformable joints to control door position. This substitutes passive friction-based positioning with active kinematic control, maintaining engagement reliability while reducing operating force.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If a simple hinge mechanism is used for the access door, then device complexity is low, but the closing force exceeds accessibility requirements

Engineering Contradiction:

Improvesimplicity of door mechanismVSAvoidclosing force

Core Design Contradiction:

Device complexityVSForce

Solution Approach 1:

The door mechanism is segmented into distinct functional components: the access door, the four-bar linkage with separate links, and the transformable compound joint. This segmentation allows each component to perform its specific function efficiently, achieving force reduction through the coordinated action of segmented elements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The introduction of the dynamic compound joint that transforms between joint types adds complexity but provides the necessary mechanical advantage to reduce closing force. The dynamic nature of the joint allows the system to adapt its characteristics during operation to meet accessibility requirements.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9996048B1Imaging device access door assembly having a low closing force

Publication Date: 2018.06.12 LEXMARK INTERNATIONAL INC

AI summary

An access door of an imaging device is movable between a raised closed position, a lowered open position, and a raised open position. A linkage assembly includes a lower link connected to the access door using a first revolute joint and an upper link connected to the access door using a compound joint. The compound joint is transformable between a prismatic joint and a second revolute joint, with the compound joint forming the prismatic joint as the access door moves between the raised closed position and the lowered open position and forming the second revolute joint as the access door moves between the lowered open position and the raised open position. The compound joint as the prismatic joint allows translational motion of the access door relative to the upper link. The compound joint as the second revolute joint allows rotational motion of the access door relative to the upper link.