Fire Department Connection Locking Cap With Friction-Resistant Removal
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Solution Overview
Problem
Existing locking caps for fire department connections are vulnerable to vandalism, theft, and damage due to material value and design flaws, such as breakage from temperature extremes and loose fitting, which compromises the security and integrity of fire sprinkler systems.
Innovation Solution
A locking cap design featuring a plug portion with a threaded region and a flange, combined with a swivel guard and wave washer, which increases frictional force for secure installation and resistance to removal, utilizing a unique patterned driver receptacle and adjustable dowel pin receivers for enhanced security and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a brass plug is used for the fire department connection, then the aesthetic match with the brass union nut is improved, but the scrap value increases making it susceptible to theft
Solution Approach 1:
The cap is constructed with a two-material design: the body is made of non-precious material (cast iron, ductile iron, or steel) while only the minimal necessary portions are made of brass to match the union nut aesthetically. This local application of brass material achieves the desired appearance match without making the entire cap valuable for scrap.
2Strength
If a cast iron cap with U-bolts is used, then the structural strength is improved, but the vulnerability to vandalism and breakage at U-bolt points increases
Solution Approach 1:
The vulnerable U-bolt attachment mechanism is completely removed from the design. Instead, the cap uses a threaded body that screws directly onto the union nut, eliminating the U-bolts and their attachment points which were identified as weak spots susceptible to vandalism and breakage.
Solution Approach 2:
Instead of attaching the cap to the union nut from the outside using U-bolts, the cap is designed to thread onto the union nut from the inside, reversing the attachment approach. This inversion creates a more secure connection that is difficult to remove without proper tools.
3Ease of manufacture
If a simple cap design is used, then the manufacturing cost is reduced, but the resistance to unauthorized removal is insufficient
Solution Approach 1:
The cap incorporates asymmetric features including a non-circular tool receiver opening and an offset slot that requires a specific tool with a matching asymmetric profile. This asymmetric design prevents removal with standard tools while maintaining a relatively simple overall cap structure that is not overly complex or expensive to manufacture.
4Ease of operation
If a cap with radial edges is used, then the tool engagement is improved, but the vulnerability to flathead screwdriver attacks increases
Solution Approach 1:
The tool receiver opening is designed with a non-circular asymmetric shape that accepts only the specific proprietary tool. This asymmetric geometry prevents engagement with flathead screwdrivers or other common tools, eliminating the vulnerability to screwdriver attacks while still providing positive engagement with the correct tool.
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 locking cap design significantly enhances the security and integrity of fire department connections by increasing the frictional force and making unauthorized removal difficult, thus protecting the sprinkler system from vandalism and theft while maintaining operational reliability.
Implementation Method 1
A locking cap design featuring a plug portion with a threaded region and a flange, combined with a swivel guard and wave washer, which increases frictional force for secure installation
Data Source
AI summary
A locking cap may be selectively locked into place within a tubular opening, such as the open end of a standpipe used to charge a building sprinkler system. The locking cap may have a plug portion. A friction load can be used to limit the unauthorized removal of the plug portion.