Fire Department Connection Locking Cap With Friction Anti-Theft Retention
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Solution Overview
Problem
Existing locking caps for fire department connections are vulnerable to vandalism, theft, and degradation due to material value and thermal expansion issues, leading to operational inefficiencies and security concerns.
Innovation Solution
A locking cap system featuring a plug portion with a threaded region and a flange, combined with a swivel guard and wave washer, which increases frictional force and resistance to removal, utilizing a unique patterned driver receptacle and adjustable dowel pin receivers to secure the cap in place, and a cam mechanism for enhanced locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a brass plug is used for the fire department connection, then the cap can be operated by a spanner wrench like the union nut, but the cap becomes susceptible to theft for scrap value
Solution Approach 1:
The cap is designed with a non-circular perimeter shape that does not match a standard spanner wrench, preventing unauthorized removal while still allowing operation with a specialized fire department tool. This asymmetric design eliminates the theft risk associated with brass plugs that have radial extensions for spanner wrench operation.
Solution Approach 2:
The cap is made from a low-value material such as plastic or painted metal instead of valuable brass, eliminating the scrap value incentive for theft. The cap is designed to be replaced rather than repaired if damaged, reducing the economic incentive for vandalism and theft.
2Strength
If a cast iron cap with U-bolts is used, then the cap can be securely attached to the union nut, but the cap becomes vulnerable to breakage at the U-bolt points and rusting over time
Solution Approach 1:
The cap is made from composite or treated materials that resist rust and corrosion, such as painted metal or plastic, eliminating the rusting problem associated with cast iron. The attachment mechanism uses corrosion-resistant fasteners and design features that distribute stress evenly, preventing breakage at attachment points.
Solution Approach 2:
The attachment mechanism is divided into multiple distributed attachment points around the cap perimeter rather than relying on a few concentrated U-bolt points. This segmentation distributes mechanical stress and prevents catastrophic failure at single points, while each attachment point is designed to be less stressed than traditional U-bolts.
3Device complexity
If a simple plug or cap is used, then the device complexity is low, but the cap is susceptible to vandalism and breakage
Solution Approach 1:
The cap features a non-circular perimeter shape with specific geometric characteristics that prevent standard tools from being used for vandalism or unauthorized removal. This simple asymmetric shape adds security without requiring complex mechanisms, maintaining low device complexity while effectively preventing vandalism.
Solution Approach 2:
The cap is made from inexpensive material such as plastic or painted metal with low scrap value, eliminating the incentive for theft and vandalism. The cap is designed as a disposable component that is replaced rather than repaired, reducing the economic motivation for malicious damage while keeping the overall system simple.
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 prevents unauthorized removal and theft, maintains operational integrity by resisting thermal expansion, and ensures the cap remains securely attached to the fire department connection, enhancing both security and reliability.
Implementation Method 1
a swivel guard and wave washer, which increases frictional force and resistance to removal
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 removal of the plug portion.