Dishwasher Soft-Open Door Damping for Bounce Control
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Solution Overview
Problem
Conventional dishwasher door opening mechanisms often require excessive force and can result in hard bounces or damage due to varying door weights and center of gravity, especially when compartments are loaded with liquids, leading to suboptimal opening parameters and user inattention.
Innovation Solution
A soft open door mechanism featuring a tension device to oppose door movement towards the horizontal position and a damping device with a partial fill damper that initiates an opposing force only when the door has moved at least 45 degrees from the upright position, providing a controlled and smooth opening by slowing down the door's motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-loaded mechanism is used to assist door closing, then the door can be held closed and reclosed automatically, but excessive force is required to initiate door opening and hard bounces occur near the fully opened position
Solution Approach 1:
The patent changes the parameters of the damping device, specifically using a variable damping coefficient that changes with door position. The damping force is minimal when the door is closed (allowing easy opening) and increases as the door approaches the fully opened position (preventing hard bounces). This is achieved through a damper with a non-linear damping characteristic where the damping coefficient varies with the velocity and position of the door.
Solution Approach 2:
The patent implements a dynamic damping system where the damping force is not constant but varies dynamically with door position and velocity. The damping device is configured to provide progressive resistance as the door opens, creating a soft-open effect that adapts to the door's movement characteristics throughout its travel range.
2Ease of operation
If the door is allowed to move freely under gravity, then opening force is reduced, but the door accelerates and bounces hard near the fully opened position causing damage
Solution Approach 1:
The patent applies preliminary anti-action by introducing a damping force that opposes the door's acceleration before the hard bounce occurs. The damping device is configured to engage progressively as the door opens, creating a counteracting force that prevents the door from gaining excessive speed and bouncing hard at the fully opened position.
Solution Approach 2:
The damping device acts as a cushioning mechanism that is activated in advance of the potential hard bounce. By providing progressive damping force as the door approaches the fully opened position, the system cushions the door's movement beforehand, preventing the harmful bounce and potential damage to stops or hinges.
3Reliability
If counterbalancing springs are made more active around the closed position, then door holding and reclosing is improved, but the force required to open the door increases
Solution Approach 1:
The patent changes the parameter distribution of the spring mechanism so that the spring force is not maximum when the door is closed but decreases as the door opens. This is achieved by positioning the spring to have minimal influence at the closed position and increasing its counterbalancing effect as the door moves toward the fully opened position, thereby maintaining reliable door holding while reducing opening force.
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 solution prevents hard bounces and damage by ensuring a smooth, controlled door opening, reducing the risk of accidents and extending the lifespan of the appliance.
Implementation Method 1
a damping device with a partial fill damper that initiates an opposing force only when the door has moved at least 45 degrees from the upright position, providing a controlled and smooth opening by slowing down the door's motion
Data Source
AI summary
A consumer appliance has a soft open door mechanism. The mechanism may include a damping device with a first end mounted to the cabinet and a second end mounted so as to move with the door. The damping device includes a partial fill damper activatable by an opening movement of the door toward the horizontal position to provide an opposing force to slow the door motion. The damper may be configured so as to initiate the opposing force only when the door has moved at least about 45 degrees from the upright position toward the horizontal position, and/or may be configured so that the damper includes a damping coefficient of about 200 to about 240 lb*s/ft.