Plastic Tank Clamped Joint Using C-Shape Clamp
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Solution Overview
Problem
Existing septic tanks assembled from molded plastic halves face challenges in maintaining a strong and leak-resistant joint during transport and use, particularly when subjected to mechanical forces, and require tools for assembly, which is not economical for mass production.
Innovation Solution
The use of C-shaped clamps with grooves and nubs to securely hold the halves together, allowing for easy assembly and disassembly without specialized tools, with features like flared portions for easy engagement and self-locking mechanisms to ensure a tight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If half tanks are joined by adhesives, then the joint has permanency, but the joining process requires joint preparation, is sensitive to substrate material properties, and requires cure time
Solution Approach 1:
The patent replaces the chemical adhesive bonding system with a mechanical fastening system using clamps. The clamps apply direct mechanical force to hold the half tanks together through flanges with nubs, eliminating the need for adhesive preparation, curing time, and reducing sensitivity to substrate material properties.
Solution Approach 2:
The patent extracts the bonding function from the adhesive material and transfers it to a separate mechanical fastening component (the clamp). This allows the joining mechanism to be independent of the tank material properties and eliminates the need for surface preparation and curing processes.
2Ease of manufacture
If half tanks are mechanically joined, then the joining is independent of substrate material properties and cure time, but the joint seal must withstand mechanical forces during transport and use
Solution Approach 1:
The patent applies local quality by creating a concentrated sealing region at the flange interface. The resilient seal is positioned specifically at the joint line where the two half tanks meet, and the clamp applies localized pressure through the nubs to compress the seal, ensuring the sealing function is optimized at the critical joint location while the rest of the tank structure remains unchanged.
Solution Approach 2:
The patent uses a composite joining system combining rigid elements (clamps, flanges, nubs) with a resilient sealing element. The rigid components provide structural strength and positioning independence, while the resilient seal provides the necessary sealing capability to withstand mechanical forces during transport and use.
3Ease of operation
If clamps are used to hold half tanks together, then assembly is simplified, but the clamps must be securely engaged to prevent leakage
Solution Approach 1:
The patent incorporates preliminary action through the pre-formed flanges with nubs that are molded as integral parts of the half tanks. These features are prepared in advance during tank manufacturing, so that during assembly, the clamps simply need to be positioned over the aligned nubs and engaged, eliminating the need for complex alignment procedures or specialized assembly tools.
Solution Approach 2:
The clamp design incorporates a self-locking mechanism where the C-shaped clamp with its open end facing the joint automatically secures itself when engaged with the nubs. The clamp's geometry and the interaction with the nubs create a self-retaining connection that maintains seal integrity without requiring additional fastening steps or specialized tools for secure engagement.
Data Source
AI summary
An injection molded plastic tank for containing liquids, such as a septic tank, is comprised of mated half tanks which are clamped together at mating flanges. A clamp having a C-shape interior concavity has grooves which engage aligned pairs of nubs on the flange surfaces which are spaced apart from the joint surfaces of each flange. A clamp has one or more flared portions at the clamp leading edge end, leading to the grooves or to the inner concavity, to make easier installation of the clamp. When a clamp reaches its home position, the clamp is locked in place against further motion in one or both directions by interacting features on the tank and clamp.