Spring-Loaded Door Hold-Open Mechanism for Refrigerated Merchandisers
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Solution Overview
Problem
Refrigerated merchandisers with doors often lose cold air due to frequent opening and closing, and existing door hold open mechanisms are not effective in maintaining the door in an open position without user intervention.
Innovation Solution
A door hold open mechanism featuring a spring-loaded elongated pin that is outwardly biased from a housing attached to the mullion, engaging with a channel along the door hinge to securely hold the door in an open position and disengage when a predetermined force is applied, allowing the door to close.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a door hold open mechanism is added to maintain the door in an open position, then cold air loss is reduced and energy efficiency is improved, but the device complexity increases
Solution Approach 1:
The door hold open mechanism is segmented into distinct functional components: a spring element for providing holding force, a roller for engagement with the channel, and a housing for mounting. This segmentation allows each component to be optimized independently and simplifies manufacturing and assembly while achieving the energy conservation goal.
Solution Approach 2:
The door hold open mechanism is designed as a self-service system that automatically maintains the door in an open position without requiring external power sources, control systems, or manual intervention. The spring-loaded roller automatically engages with the channel when the door is opened and maintains the open position passively, reducing both device complexity and energy consumption.
2Ease of operation
If a spring-loaded engagement member is used to hold the door open, then the door can be easily held in any position, but the mechanism complexity increases
Solution Approach 1:
The engagement function is extracted from complex motorized or manual systems and implemented through a simple spring-loaded roller that passes through a channel. This extraction reduces mechanism complexity while maintaining ease of operation, as the roller naturally follows the channel geometry to provide smooth positioning.
Solution Approach 2:
The spring constant and roller diameter are optimized to provide sufficient holding force for various door weights and sizes. By adjusting these parameters, the mechanism accommodates different door configurations without requiring complex adaptive controls, thus maintaining ease of operation while limiting complexity increases.
3Reliability
If the engagement member is outwardly biased to engage with the channel, then reliable door holding is achieved, but the force required to close the door increases
Solution Approach 1:
The spring-loaded roller provides dynamic engagement where the spring force automatically adjusts to the door's weight and position. When the door is closed, the roller naturally disengages from the channel without requiring excessive force, as the spring compression decreases. This dynamic behavior maintains reliable holding during operation while minimizing closing force requirements.
Solution Approach 2:
The engagement and disengagement of the roller with the channel occurs periodically as the door moves between open and closed positions. The spring force is applied only when needed to maintain the open position, and naturally releases when the door closes, reducing the overall force burden compared to continuously engaged mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The mechanism effectively keeps the door open without manual assistance, reducing energy loss by minimizing cold air escape and allowing easy access to the product display area, while also being adaptable for retrofitting onto existing merchandisers.
Implementation Method 1
a spring-loaded elongated pin that is outwardly biased from a housing attached to the mullion
Data Source
AI summary
A merchandiser including a case defining a product display area for supporting and displaying food product. The case includes a case frame that has at least one mullion defining an opening into the product display area, a door that is positioned over the opening and pivotably coupled to the case frame for movement between a closed position and an open position, and a door hold open mechanism attached to either the mullion or the door. The other of the mullion and the door defines a channel, and the door hold open mechanism includes an engagement member that is outwardly biased from the mullion or the door to which the door hold open mechanism is attached such that the engagement member is engageable with the other of the mullion and the door within the channel to hold the door in the open position.