Self-Powered Door Closer Harvesting Energy via Motor and Spring
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Solution Overview
Problem
Existing door closer systems face challenges in ensuring doors can close effectively under varying conditions, such as pressure differentials and heavy doors, without exceeding force limits required by regulations like the Americans with Disabilities Act, and often require external power assistance.
Innovation Solution
A self-powered door closer system utilizing a motor that harvests energy during door opening and stores it for a boost to ensure complete closure, incorporating a mechanical interface with a spring, gear set, and energy storage, allowing operation independently of external power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a weak spring is used to meet force limits, then the door can open within regulatory limits, but the door cannot close effectively under pressure differentials or heavy loads
Solution Approach 1:
The door closer system dynamically adjusts the force characteristics during the door operation cycle. The motor provides variable assistance - minimal force during opening to meet accessibility requirements, and substantial boost force during closing to overcome pressure differentials and heavy door weights. This dynamic force adjustment resolves the contradiction between weak spring force and reliable door closing.
Solution Approach 2:
The motor acts as an intermediary between the weak spring and the door, providing supplemental force when needed. During opening, the motor minimizes interference to allow compliant operation. During closing, the motor intervenes to provide the additional force required to overcome adverse conditions, effectively mediating between the weak spring's limitations and the door's closing requirements.
2Reliability
If a motor is added to assist door closing, then the door can close under heavy loads, but the system requires external power sources
Solution Approach 1:
The door closer system is self-powered, harvesting energy from the door's own motion. The motor functions as a generator during door opening, converting the mechanical energy of the moving door into electrical energy that is stored in the energy storage device. This stored energy is then used to power the motor during door closing, eliminating the need for external power sources while maintaining reliable door closing capability.
Solution Approach 2:
The system recovers energy that would otherwise be wasted during door opening. The motor captures the kinetic energy and potential energy from the door's motion during opening, stores it in the energy storage device, and recovers it during closing to provide the necessary boost force. This energy recovery mechanism eliminates external power requirements while ensuring reliable door closing.
3Power
If the spring is compressed upon opening, then the spring can close the door, but the force required to open the door may exceed regulatory limits
Solution Approach 1:
The system replaces the purely mechanical spring-based door closer with an electromechanical system. The motor, powered by energy harvested from door motion, substitutes for the need to pre-compress the spring to high forces. This allows the spring to be configured for closing power while the motor handles the force requirements during opening and closing, resolving the contradiction between closing power and 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 system effectively ensures doors can close completely under diverse conditions without external power, adhering to regulatory force limits, and includes mechanisms to protect against excessive loads through clutch mechanisms.
Implementation Method 1
The motor is configured to generate electricity while impeding rotation of the pinion
Implementation Method 2
the spring is compressed upon opening the door and allowed to expand in order to close the door
Implementation Method 3
The motor is operable with the electricity to rotate the gear set to rotate the pinion in the second direction
Data Source
AI summary
A door closer system is provided that includes a motor, a spring, a reduction gear set, and a rack and a pinion mechanism. The spring and pinion may be coupled to the rack, and the pinion may be selectively coupled to the gear set. The motor may be selectively mechanically coupled to the gear set. The pinion may rotate in a first direction via the rack as the spring is compressed in a second direction opposite the first direction as the spring is expanded. The motor is operable to rotate and act upon the pinion through the gear set, thereby rotating the pinion in the second direction and assist the spring in closing the door.