Thin-Walled Pressing Sleeve for Low-Force Pipe Fittings
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Solution Overview
Problem
Existing pipeline fittings require high forming and pressing forces, often resulting in leaky connections and damage to pressing tools due to high geometry and material thickness, especially when using stainless steel sleeves, which are difficult to handle with small motor-driven or hand-operated tools.
Innovation Solution
A pressing sleeve made of metal with microhardness less than 65 HV1, specifically copper or aluminum alloys, with a wall thickness to outer diameter ratio of less than 0.06, allowing for easier forming and reduced pressing forces, enabling a uniform radial pressing that eliminates the need for additional elastomer seals and prevents pressing folds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stainless steel pressing sleeves with high geometry and material thickness are used, then connection stability is improved, but forming and pressing forces become excessively high requiring expensive electric pressing machines
Solution Approach 1:
The patent changes the material parameter from stainless steel to aluminum alloy, which has lower microhardness and better formability. This parameter change reduces the forming and pressing forces required while maintaining connection stability through optimized wall thickness ratios (less than 0.06) and controlled microhardness (less than 65 HV1).
Solution Approach 2:
The patent employs a thin-walled pressing sleeve design with wall thickness to outer diameter ratio less than 0.06, creating a flexible structure that can be easily formed by pressing tools. This thin-walled design reduces the forces required for forming while the aluminum alloy material provides sufficient strength for stable connections.
2Reliability
If highly contoured pressing geometries are used, then connection stability is improved, but pressing folds form and damage pressing jaws
Solution Approach 1:
The patent changes the material parameter to aluminum alloy with specific microhardness characteristics, which is more formable and less prone to creating pressing folds. This material parameter change allows for stable connections without the harmful effects of material folding during the pressing process.
Solution Approach 2:
The patent converts the potential harm of thin-walled construction (which could lead to folding) into a benefit by selecting aluminum alloy material that is sufficiently formable. The material's properties transform what would be a weakness into an advantage, enabling easy forming without pressing folds while maintaining connection stability.
3Reliability
If elastomer seals are added to ensure tight connections, then connection tightness is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the elastomer seal component from the sealing system. By using aluminum alloy pressing sleeves with optimized geometry and material properties, the patent achieves tight connections through the metal-to-metal contact between the pressing sleeve and pipe, removing the need for additional sealing elements and simplifying the overall device.
4Duration of action of stationary object
If stainless steel pressing sleeves are used, then durability is improved, but ease of operation with hand tools deteriorates due to high actuating forces required
Solution Approach 1:
The patent changes the material parameter from stainless steel to aluminum alloy, which has lower microhardness and better formability. This parameter change reduces the actuating forces required for hand-operated tools while the optimized wall thickness and geometry maintain sufficient durability for the application.
Solution Approach 2:
The patent employs a pressing sleeve design that prioritizes ease of installation with simple tools over extreme durability. The aluminum alloy sleeve is designed for reliable performance in its service life without requiring the high durability of stainless steel, allowing for easier operation with hand or battery-operated pressing tools.
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 solution reduces forming work, error susceptibility, and costs, allowing for the use of simpler pressing tools, such as battery-operated drivers or hand tools, and ensures a tight, stable connection suitable for construction sites and repairs.
Implementation Method 1
a pressing section of a fitting is formed radially inwards using a pressing tool when the pipe section is inserted, so that a permanent and tight connection is produced
Data Source
AI summary
The invention relates to a fitting to be connected to at least one pipe, in particular a plastic pipe or plastic-metal composite pipe, having a main body, having at least one supporting body connected to the main body for insertion into a pipe end and having at least one pressing sleeve connected to the main body for receiving the pipe end, the pressing sleeve having a cylindrical pressing section. The technical problem of improving the fitting for pressing, in particular with small motor-driven or manually driven pressing tools, is solved by the fact that the pressing sleeve is made of a metal with a microhardness of less than 65 HV 1, in particular less than 50 HV 1, preferably in the range from 40 to 50 HV 1 measured according to Vickers, and that the ratio of wall thickness of the pressing section to the outer diameter of the pressing section is less than 0.06, preferably in the range from 0.03 to 0.06. The invention also relates to a method for establishing a connection.