Inspection Hatch Fastener Shield for Explosion Shear Containment
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Solution Overview
Problem
Existing solutions fail to prevent the projection of screw heads and other fixing means inside a structure during explosions, posing a risk to occupants, as they are not effectively secured against shear forces.
Innovation Solution
An anti-projection protection device featuring a deformable plate with connecting lugs and screws that interpose the screw heads between the plate and the wall, using notches and holes to secure the plate in place, preventing the screws from being projected inward.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If through connections are used to fix internal elements outside the wall, then the risk of projection of fastening means is reduced, but the heads of screws or bolts are still liable to be sheared off and thrown inside the structure
Solution Approach 1:
A plate is introduced as an intermediary element between the wall and the fixing means. The plate receives the impact of sheared screw heads or bolts, preventing them from being projected inside the structure. The plate acts as a mediator that absorbs the harmful projection effect while maintaining the structural connection.
Solution Approach 2:
The plate is pre-installed on the wall before the fixing means are attached. This preliminary positioning ensures that when screws or bolts are sheared during explosion impact, their heads are already constrained by the plate and cannot be projected inward, providing proactive protection rather than reactive mitigation.
2Object-affected harmful factors
If a plate is placed at a distance from the fixing means to prevent projection, then occupant safety is improved, but the device complexity increases due to additional components and installation steps
Solution Approach 1:
The protective plate is merged with the fixing system by integrating connection lugs directly onto the plate. These lugs serve dual purposes: they attach the plate to the wall and simultaneously secure the fixing means. This combination reduces the number of separate components compared to having independent protective plates and fixing systems.
Solution Approach 2:
The plate performs multiple functions simultaneously: it prevents projection of fixing means, provides structural support, and serves as a mounting surface for connection lugs. This multi-functionality reduces the need for additional specialized components, thereby simplifying the overall device despite the added protection capability.
3Strength
If connecting screws are used to fix the plate to the wall, then the plate can be securely attached, but the screws themselves may be sheared and projected during explosion
Solution Approach 1:
Connection lugs serve as intermediary elements between the plate and the wall, replacing direct screw attachment. The lugs are deformable elements that absorb impact forces through deformation rather than rigid screw connections, preventing the screws from being sheared and projected while maintaining secure attachment.
Solution Approach 2:
The connection system transitions from rigid screw-only attachment to a deformable lug-based connection. The lugs change their physical state from rigid to deformable under impact, allowing them to absorb shear forces through controlled deformation rather than brittle failure, thereby preventing screw projection.
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 device effectively prevents the projection of fixing means inside the structure by absorbing deformations and maintaining the plate's position, ensuring the screws remain trapped and do not enter the structure, thus enhancing occupant safety.
Implementation Method 1
deformable connecting lugs, fixed to the plate, and on which connecting screws engage
Implementation Method 2
the connecting legs comprising notches allowing the heads of the connecting screws to be engaged between the plate and the leg in question
Data Source
Figure 1a~1b
Figure 2a~3
Figure 4a~4b
AI summary
The invention relates to an anti-projectile protection device (1) for an attachment means (7) of a member (8) attached to a wall (4) of a structure. This device is characterized in that it comprises a plate (2) designed to be spaced apart from the attachment means (7) and fixed directly or indirectly to the wall (4) by means of deformable connecting tabs (5) which are secured to the plate (2) and on which engage connecting screws (3). The heads (3a) of the connecting screws (3) are interposed between the plate (2) and the tab (5) in question and holes (12) are created in the plate (2) to allow the connecting screws (3) to be tightened. The connecting tabs (5) comprise notches (9) such that the heads (3a) of the connecting screws (3) can be engaged between the plate (2) and the tab (5) by simple translation of the plate (2) when they are installed in their tapped holes. The invention also relates to an inspection hatch incorporating such a protection device.