Magnetic Door Closer Resolving Spring Failure and Housing Volume
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Solution Overview
Problem
Conventional door closers require large springs to achieve high forces for fire regulations, leading to premature spring failure and inefficiency, and are bulky due to the need for additional mechanisms to modify force profiles.
Innovation Solution
A door closer using magnetic means, including permanent magnets, to provide a high attractive force for closing and resistance to opening, which is compact and efficient, eliminating the need for large springs and allowing for a more desirable force profile with a combination of magnetic attraction and biasing members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional spring mechanism is used to provide high closing force, then the door can meet fire regulation forces, but the spring undergoes high stress leading to premature failure and the housing becomes large
Solution Approach 1:
The patent replaces the conventional mechanical spring system with a magnetic field-based system. Permanent magnets mounted on the drive member interact with ferromagnetic material in the housing to generate closing force, eliminating the need for high-stress mechanical springs and improving reliability
Solution Approach 2:
The patent changes the physical state and properties of the closing mechanism from elastic mechanical deformation (springs) to magnetic field interaction. By adjusting magnet strength, positioning, and ferromagnetic material properties, the desired force profile is achieved with lower stress on components
2Force
If additional mechanisms such as cam or kinematic linkage are incorporated to modify force profile, then the force distribution can be optimized, but the device complexity and housing size increase
Solution Approach 1:
The patent eliminates complex mechanical force-modification mechanisms like cams and linkages by using the magnetic field's natural properties. The magnetic force can be tailored through magnet arrangement and strength to provide the desired force profile without additional mechanical components
Solution Approach 2:
The magnetic system performs multiple functions simultaneously: it provides the closing force, shapes the force profile through magnet arrangement, and eliminates the need for separate force-modification mechanisms, reducing overall device complexity
3Force
If large springs are used to generate high torque for door closing, then the required force can be achieved, but the door closer housing becomes large and cannot be fitted in confined spaces
Solution Approach 1:
The patent replaces large mechanical springs with compact permanent magnets and ferromagnetic material, dramatically reducing the housing volume required to generate the same closing torque. The magnetic field generates force without requiring the physical space that mechanical springs occupy
Solution Approach 2:
The patent changes from mechanical energy storage (spring compression) to magnetic field energy storage, enabling high torque generation in a compact volume by optimizing magnet strength, size, and positioning relative to the ferromagnetic material
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 magnetic door closer is compact, efficient, and provides a desirable force profile with reduced spring requirements, enhancing reliability and space efficiency while meeting fire regulation forces.
Implementation Method 1
at least one first and second magnetic means arranged in the housing with their opposite poles facing one another such that there is a magnetic force of attraction between them
Data Source
AI summary
A door closer has a housing for connection to a door and a drive spindle (10) coupled to the door. As the door moves the spindle (10) and housing (11) rotate relative to one another. The relative movement is translated by a piston and cam mechanism (21, 22) into a force that is used to separate a pair of magnets (28). The magnetic attraction of the magnet pairs (28) serves as a force to resist opening of the door and biases the door from an open to a closed position. At least one first magnet is coupled to the drive member and at least one second magnet (32) coupled to the housing. The magnets are arranged in the housing with their opposite poles facing one another such that there is a magnetic force of attraction between them. At least one further biasing spring (36) may be provided to provide a biasing force after the magnetic force has diminished by separation of the magnets.