Spin Welding Flexible Hose to Thermoplastic Fitting
Solution Overview
Problem
Existing methods for producing pressure-tight hose and fitting assemblies for connecting apparatuses to water mains face challenges such as high production costs, leakage risks, and reduced flexibility due to the use of crimped metal bushings and rigid thermoplastic materials, which are not effectively addressed by alternative solutions like overmolding or thermoforming that require hoses without reinforcing braids.
Innovation Solution
A method involving a pressure-tight flexible hose with a thermoplastic material and braided reinforcing layer, where the hose is spin-welded to a thermoplastic fitting with an annular seat and collecting groove, allowing the thermoplastic material to solidify and form a solid bridge over the braided layer, ensuring a strong and flexible connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crimped metal bushing is used to connect the fitting to the hose, then the connection is secure and pressure-tight, but the production cost increases and there is a risk of leakage and waste at the crimped interface
Solution Approach 1:
The patent merges the fitting and hose into a monolithic assembly where the fitting is directly overmolded onto the hose, eliminating the separate metal bushing component. This integration removes the crimped interface that causes leakage risks and reduces production steps, thereby lowering manufacturing costs while maintaining connection reliability.
Solution Approach 2:
The invention extracts and removes the metal bushing component from the assembly, replacing it with a direct thermoplastic-to-thermoplastic overmolding process. This elimination of the intermediate metal component removes the source of leakage and waste at the crimped interface while simplifying the manufacturing process.
2Ease of manufacture
If overmolding or thermoforming techniques are used to join the fitting directly to the hose, then production cost is reduced and leakage risk is minimized, but the hose must be free from reinforcing braid which weakens the welding
Solution Approach 1:
The patent applies local quality by creating a localized bonding zone at the interface between the fitting and hose through overmolding. The thermoplastic material of the fitting is molded directly onto the thermoplastic layer of the hose, creating a strong molecular bond at this specific location while allowing the reinforcing braid to remain intact in other areas of the hose.
Solution Approach 2:
The invention utilizes composite materials by combining the thermoplastic hose layer with the thermoplastic fitting material through overmolding. This composite structure allows the reinforcing braid to remain embedded in the hose while the thermoplastic layers bond together, creating a strong monolithic connection that maintains both strength and flexibility.
3Reliability
If a monolithic hose and fitting assembly is made with overmolding, then leakage risk is reduced, but the hose must be made of rigid or semi-rigid thermoplastic materials which have high rigidity making installation difficult
Solution Approach 1:
The patent applies parameter changes by selecting thermoplastic materials with specific properties that balance rigidity and flexibility. The hose is made from thermoplastic material that maintains sufficient rigidity for pressure-tight connections while retaining enough flexibility for easy installation and bending, unlike rigid or semi-rigid materials that are difficult to install.
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
This method achieves a firm, leak-proof connection with high flexibility, reducing production costs and eliminating potential weakening points, while maintaining the necessary pressure-tightness and ease of installation, with improved weld quality and reduced waste.
Implementation Method 1
fastening said hose fixing end to the fitting fixing end, by means of spin welding
Implementation Method 2
allowing the thermoplastic material to solidify and form a solid bridge
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
Method of producing a pressure-tight hose and fitting assembly (1), suitable for connecting an apparatus to the water mains, said method comprising the following steps: - preparing a pressure-tight flexible hose (10), comprising at least one layer of thermoplastic material (12,14) and at least one braided reinforcing layer (13), said flexible hose (10) having a hose fixing end (11); - preparing a fitting (20) made of a thermoplastic material, having a fitting fixing end (21), in which an annular housing (22), of a sized suitable for receiving the hose fixing end (11) is formed; - inserting the hose fixing end (11) inside the annular seat (22) of the fitting (20); - fastening said hose fixing end (11) to the fitting fixing end (21), by means of a spin welding.