Refrigerator Hands-Free Door Opening Using Foot-Activated Sensing
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Solution Overview
Problem
Conventional refrigerators require users to use both hands to open the door, which can be inconvenient, especially when carrying objects, and existing solutions for assisted door opening often have issues with long leverages and misrecognition of users or objects.
Innovation Solution
A refrigerator system that uses a sensing assembly to detect a user's presence and project an image on the floor, allowing the door to be opened automatically by a user's foot, even when hands are occupied, with a projector and detection device ensuring accurate operation and preventing misrecognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnet is provided inside the gasket to increase adhesion with the cabinet, then the leaking of cool air is decreased, but a greater force is required to open the door
Solution Approach 1:
A push rod is introduced as an intermediary mechanical element between the user's manual operation and the door. The push rod transfers and amplifies the opening force, mediating between the user's limited input force and the high magnetic adhesion force that must be overcome to open the door.
Solution Approach 2:
The solution moves from direct linear force application at the handle to rotational moment application through a lever arm. By positioning the push rod to act at a point far from the hinge axis, the system exploits the rotational dimension and moment arm principle to reduce the required opening force.
2Force
If a door opening device with a long rod is used to push the door open from a position distant from the hinge shaft, then the door can be opened with less force, but the length of the rod becomes very long
Solution Approach 1:
The push rod is designed with a telescopic or nested structure that allows it to extend to the necessary length during door opening operation, then retract into a compact form when not in use. This nesting principle allows the rod to achieve the required functional length without permanently occupying excessive space within the door structure.
Solution Approach 2:
The rod transitions from a static, fixed-length component to a dynamic, variable-length component. The rod extends to its full operational length only when needed for door opening, and retracts or folds to a shorter configuration during normal door closed or open states, adapting its length to the operational requirements.
3Force
If an operating part on the door handle is required to activate the door opening device, then the door can be opened with assistance, but it becomes impossible to operate when the user is holding objects with both hands
Solution Approach 1:
The door opening system activates itself through automatic sensing of the user's presence or intent to open the door. The sensing assembly detects when the user approaches or intends to open the door, and the control system automatically triggers the push rod mechanism without requiring manual activation, allowing the door to serve itself in the opening action.
Solution Approach 2:
The manual mechanical operation of the door handle is replaced with an automatic sensing and actuation system. Optical or proximity sensors substitute for mechanical handle operation, detecting the user's presence and automatically activating the motorized or pneumatic push rod mechanism to open the door.
4Ease of operation
If a sensing assembly is provided to enable automatic door opening, then hands-free operation is achieved, but the device complexity increases
Solution Approach 1:
The sensing assembly is designed to perform multiple functions: detecting user presence, determining intent to open the door, and triggering the appropriate actuation sequence. By making the sensing system multi-functional, the patent reduces the need for separate dedicated sensors for each detection task, thereby limiting the increase in overall device complexity.
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
Enables convenient and reliable hands-free door opening by accurately detecting user input, reducing the risk of accidental operation and fitting within the restricted space of a standard refrigerator door, while maintaining insulation performance.
Implementation Method 1
A refrigerator system that uses a sensing assembly to detect a user's presence
Implementation Method 2
project an image on the floor, allowing the door to be opened automatically
Data Source
Figure 1
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AI summary
Provided is a refrigerator (1) and control method for refrigerator and method for opening a refrigerator door (20). While a user is holding an object in both hands, a door (20) may be automatically and additionally opened using another part of a body other than hands.