Weldless Bailer Snap-Fit Assembly for Dissimilar Plastics

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Solution Overview

Problem

Conventional bailers for collecting liquid samples face issues with weak weld bonds, especially when using dissimilar plastics, leading to assembly and reliability problems due to the high cost of ultrasonic welding.

Innovation Solution

A weldless bailer design featuring snap-fit end caps and a weighted member for anti-buoyancy, which eliminates the need for welding and provides a strong, cost-effective assembly solution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If spot welding is used to assemble end caps to the bailer body, then the assembly process is simple, but the bond strength is too weak and may come apart in use

Engineering Contradiction:

Improveassembly process simplicityVSAvoidbond strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent replaces the welding process (thermal/mechanical system) with a mechanical interference fit system consisting of ridges on the end caps that engage with grooves in the bailer body. This mechanical engagement provides both ease of assembly and strong bonding without the need for welding equipment or procedures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The end caps are segmented with multiple ridges (typically 3-6 radial ridges) that engage with corresponding grooves in the bailer body. This segmentation distributes the bonding stress across multiple engagement points, providing both strong overall bonding and ease of assembly through simple radial insertion.

Inventive Principle:

Principle #1Segmentation

2Strength

If ultrasonic welding is used to assemble end caps to the bailer body, then the bond strength is strong, but the production cost is prohibitively expensive

Engineering Contradiction:

Improvebond strengthVSAvoidproduction cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent employs inexpensive molded plastic components with integrated ridges and grooves that can be assembled using simple tools. This approach replaces expensive ultrasonic welding equipment and processes with low-cost molded features and manual or automated snap-fit assembly, dramatically reducing production costs while maintaining adequate bond strength for the application.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes the expensive ultrasonic welding mechanical system with a simple mechanical interference fit system. The ridges and grooves are molded into the plastic components, eliminating the need for ultrasonic welding equipment, skilled operators, and complex process control, thereby drastically reducing manufacturing costs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If welding is used to assemble dissimilar plastics in the bailer, then a strong bond is needed, but welding dissimilar plastics is problematic and costly

Engineering Contradiction:

Improvebond strength for dissimilar plasticsVSAvoiddifficulty of welding dissimilar plastics

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the bonding mechanism from thermal welding (which has difficulty with dissimilar plastics) to mechanical interference fit. The ridges and grooves are designed with specific dimensional parameters (ridge height, groove depth, radial engagement) that provide strong bonding for dissimilar plastics without requiring the plastics to be weldable to each other.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the welding process (which is problematic for dissimilar plastics) with a mechanical interference fit system. The ridges on one plastic component engage with grooves in another plastic component, providing strong bonding that works equally well with dissimilar plastics regardless of their welding compatibility.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 snap-fit assembly ensures a secure and reliable connection without the need for welding, enhancing the bailer's durability and ease of production while maintaining anti-buoyancy and efficient liquid sampling.

Implementation Method 1

the ridges of the top and bottom caps are configured to form snap fits with the corresponding grooves of the cylindrical body

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a weighted member is provided in the bailer to provide anti-buoyancy to the bailer

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentUS10935471B2Weldless bailer

Publication Date: 2021.03.02 AQUA BAILERS INC

AI summary

A liquid sampling device including a cylindrical body having a first plurality of grooves formed with irregular spacing near a first end of the cylindrical body, and a second plurality of grooves formed with irregular spacing near a second end of the cylindrical body, a top cap having an insertion portion to fit inside the cylindrical body and having a plurality of ridges formed thereon to correspond to the first plurality of grooves, and a cap portion having a suspension member, and a bottom cap having an insertion portion to fit inside the cylindrical body and having a plurality of ridges formed thereon to correspond to the second plurality of grooves, and an external annular flange forming an opening in the bottom cap to pass liquid therethrough, wherein the ridges of the top and bottom caps are configured to form snap fits with the corresponding grooves of the cylindrical body.