Hinge Bolt Insert for Sawing Resistance
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Solution Overview
Problem
Existing hinges often lack sufficient burglary protection, are complex to manufacture, or compromise visual appearance, with inadequate resistance to cutting attempts, such as sawing through the hinge bolt.
Innovation Solution
A hinge bolt with an insert that provides increased burglary security by allowing rotation during cutting attempts, reducing friction with a clearance fit or lubrication, and a securing element to prevent removal, maintaining structural integrity and appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional hinge pin is used, then the hinge is simple to manufacture and install, but it offers insufficient burglary protection and is easily cut through with a hacksaw
Solution Approach 1:
An insert is placed inside the hinge pin bore, creating a nested structure where the insert is contained within the hinge pin. This nested design increases burglary protection without significantly altering the external appearance or complexity of the hinge assembly.
Solution Approach 2:
The hinge pin combines two different materials: the base hinge pin material and the insert material (which may be harder or have different cutting resistance properties). This composite structure provides enhanced resistance to cutting attempts while maintaining the simplicity of the overall hinge design.
2Reliability
If the insert is tightly fitted in the hinge pin, then it is secured against removal, but friction increases and rotation during cutting attempts is hindered
Solution Approach 1:
A locking element acts as an intermediary between the insert and the hinge pin bore. This locking element secures the insert axially while allowing it to rotate freely during cutting attempts, thus mediating between the need for retention and the need for rotational freedom.
Solution Approach 2:
The securing mechanism is segmented into separate functional elements: the insert itself and a distinct locking element. This segmentation allows the locking element to perform the retention function without interfering with the insert's rotational movement during cutting attempts.
3Strength
If the insert is made harder than the hinge pin, then resistance to sawing attempts increases, but the insert becomes more susceptible to breaking or chipping
Solution Approach 1:
The hardened insert is nested within the larger hinge pin structure, which provides structural support and containment. This nesting allows the insert to be harder for cutting resistance while the surrounding hinge pin material provides a buffer that reduces the risk of catastrophic failure.
Solution Approach 2:
The hinge pin structure serves as a cushioning element around the harder insert. When the insert is subjected to cutting forces, the surrounding softer hinge pin material absorbs and distributes these forces, preventing sudden brittle failure of the hard insert.
4Strength
If the insert can rotate freely during cutting attempts, then cutting resistance is maximized, but the insert may become loose or fall out
Solution Approach 1:
A locking element serves as an intermediary that selectively constrains the insert: it prevents axial movement (keeping the insert in place) while allowing rotational movement (maintaining cutting resistance). This mediator resolves the contradiction between free rotation and retention.
Solution Approach 2:
The locking constraint is applied locally and selectively: the locking element restricts only the axial degree of freedom while leaving the rotational degrees of freedom unrestricted. This local application of constraint allows the insert to rotate freely for cutting resistance while preventing loosening or falling out.
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 bolt offers enhanced resistance to break-in attempts while maintaining a conventional appearance and ease of assembly, as the insert rotates during cutting, preventing penetration and ensuring a secure connection between the hinge parts.
Implementation Method 1
Measures have been taken to minimize friction between the insert and the band bolt during rotation. This minimizes resistance to rotation driven by the cutting tool. These friction-reducing measures include a clearance fit between the insert and the bore in the band bolt and/or lubrication of the insert.
Data Source
Figure 1~4
AI summary
A hinge (100) for pivoting a leaf to a frame, in particular a door leaf to a door frame, with a leaf hinge part (7), a frame hinge part (8) and a hinge bolt (1), wherein, to increase burglary resistance, an insert (2) is provided in the hinge bolt (1) which is long and arranged so that it covers an area (C) between the leaf hinge part (7) and the frame hinge part (8), and the insert (2) has one degree of freedom about its own axis (A) so that the insert (2) rotates during a sawing attempt, and a separately designed locking element (4) is provided to secure the insert (2) in the hinge bolt (1).