Anti-Ligature Door Hinge With Threshold Force Release
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Solution Overview
Problem
Existing door hinges pose a ligature risk for vulnerable individuals, particularly those with mental health issues, as they can be used to support hanging attempts, and existing anti-ligature solutions are complex, costly, difficult to install, or create new points of risk.
Innovation Solution
A hinge design that disconnects from its bracket in response to predetermined force thresholds, either transverse or axial, with magnetic and resilient biasing means to prevent ligature points, and a leaf system that minimizes clearance and guides ligatures away from the hinge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional butt hinge is used for door self-closing mechanisms, then the door can effectively self-close, but ligature points are created at the hinge and spring arm
Solution Approach 1:
The patent removes the traditional spring arm component that creates ligature points and extracts the self-closing function into a separate concealed mechanism positioned between the transom and door, eliminating exposed ligature points while preserving the self-closing capability
Solution Approach 2:
The self-closing mechanism is nested within the door assembly structure, with the spring mechanism concealed between the transom and door when closed, creating a compact integrated system that eliminates external ligature points
2Object-affected harmful factors
If a continuous geared hinge system is used to eliminate ligature points, then ligature risks are reduced, but the system becomes complex and expensive to install
Solution Approach 1:
The patent extracts the self-closing function from the hinge assembly itself and places it in a separate concealed mechanism, allowing the hinge to remain a simple butt hinge without complex geared mechanisms while still eliminating ligature points through the concealed spring arm design
Solution Approach 2:
Instead of making the hinge itself complex to prevent ligature points, the patent inverts the approach by concealing the self-closing mechanism within the door structure, thereby simplifying the hinge while achieving the same safety objective
3Object-affected harmful factors
If a continuous hinge along the full length of the door is used, then ligature points on the hinge are avoided, but installation difficulty increases and friction is added
Solution Approach 1:
The patent extracts the self-closing function from a continuous hinge system and implements it as a separate concealed mechanism at the top of the door, allowing the use of a simple top hinge that is easy to install while still preventing ligature points through the concealed spring mechanism
Solution Approach 2:
The patent segments the door closing function from the hinge assembly, placing the self-closing mechanism in a separate location (between transom and door) rather than requiring a continuous hinge along the full door length, thereby simplifying installation while maintaining safety
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 hinge effectively prevents the use of doors as ligature points by disconnecting under controlled forces, reducing the risk of self-harm and ensuring doors cannot support or reattach ligatures, while being user-friendly and cost-effective.
Implementation Method 1
a resilient member, such as a spring
Implementation Method 2
a magnetic member
Data Source
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AI summary
An anti-ligature hinge for a door and associated methods and systems are provided. The anti-ligature hinge has a hinge bracket operatively associable with a support and a hinge member operatively associable with a leaf. The hinge member is connectable to the hinge bracket and rotatable relative to the hinge bracket about an axis of rotation. The hinge member can disconnect from the hinge bracket in response to a threshold force acting along or transverse to the axis or rotation. This hinge is for eliminating ligature points in doors where vulnerable individuals are to be left unsupervised.