Shear-Thickening Door Hinge for Anti-Slam Motion Control
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Solution Overview
Problem
The slamming of doors can cause harm to individuals or pets, damage equipment, and produce unpleasant noises due to uncontrolled motion, and existing solutions do not adequately address these issues.
Innovation Solution
The use of Shear Thickening Fluid (STF) in door hinges to control door motion by transitioning from a viscous liquid to a solid-like state under increased pressure, combined with mechanical components to adjust resistance and dampen sudden closures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a door is allowed to close freely without resistance, then the door closes easily and quickly, but the door may slam causing harm to people, damage to equipment, and unpleasant noises
Solution Approach 1:
The patent applies parameter changes by utilizing a shear thickening fluid that changes its viscosity parameter based on the shear rate applied to it. During normal door closure, the fluid maintains low viscosity for easy movement. When the door accelerates toward slamming, the increased shear rate causes the fluid to thicken, providing resistance and dampening the slam while allowing the door to close smoothly under normal conditions.
Solution Approach 2:
The patent implements dynamics by employing a fluid whose properties are not fixed but dynamically change in response to operational conditions. The shear thickening fluid transitions from a runny state during normal closure to a thick, resistive state when the door approaches slamming velocity, enabling the system to adapt its damping characteristics to the instantaneous motion state of the door.
2Object-affected harmful factors
If resistance is added to the door hinge to prevent slamming, then door slamming is dampened, but the door becomes difficult to close under normal conditions
Solution Approach 1:
The shear thickening fluid changes its resistance parameter dynamically based on the shear rate. During normal, slow door closure, the fluid maintains low viscosity and offers minimal resistance. When the door accelerates rapidly, the high shear rate triggers the fluid to thicken, providing the necessary resistance to dampen the slam. This parameter change allows the system to provide resistance only when needed.
Solution Approach 2:
The system dynamically adjusts the damping characteristic of the hinge by using a fluid whose viscosity changes with the rate of deformation. The fluid remains compliant during normal operation but becomes resistive when the door approaches slamming conditions, enabling the hinge to adapt its mechanical properties in real-time based on the door's motion state.
3Reliability
If a fixed resistance mechanism is used in the door hinge, then the resistance is consistent, but the resistance cannot adapt to varying door closure speeds and forces
Solution Approach 1:
The shear thickening fluid provides variable resistance that automatically adapts to the door closure speed and force. The fluid's viscosity parameter changes in response to the shear rate, which is determined by the door's instantaneous motion characteristics. This allows the hinge to provide smooth, low resistance during slow closure and high resistance during rapid closure, without requiring external control systems.
Solution Approach 2:
The shear thickening fluid is self-regulating and automatically adjusts its resistance properties based on the mechanical conditions imposed upon it by the door motion. The fluid senses the shear rate through its own deformation and responds accordingly, providing the appropriate damping level without external intervention or complex control 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 system effectively dampens door slamming, preventing injury and noise, while allowing smooth closure under normal conditions, and providing adjustable resistance to manage varying closure forces.
Implementation Method 1
STF is relaxed at rest and behaves nearly like most viscous liquids under minimal shear or pressure... When pressure or shear forces are applied, the fluid stiffens instantaneously
Data Source
AI summary
Systems and devices to control rotational and/or arcuate motion are provided herein. In some examples, a hinge system is configured to replace a conventional door hinge and to control motion of the door. In some examples, a hinge system is configured to replace a conventional door hinge and to control motion of the door by employing a shear thickening fluid. In some examples, a door closure system is configured to replace a conventional door hinge and to control motion of the door by employing two opposing springs.