Dual-Mandrel PEX Expansion Jaws for Uniform One-Second Cycling
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Solution Overview
Problem
Existing PEX expansion tools are inefficient in terms of cycle time and uniform expansion of PEX tubing, leading to suboptimal connection with fittings.
Innovation Solution
An expansion tool with a mandrel system that includes a first and second mandrel, movable relative to each other, and jaws that expand and retract rapidly, driven by a motor and drive mechanism, allowing for even expansion and contraction of the jaws within one second or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single mandrel is used in existing PEX expansion tools, then the device complexity is reduced, but the uniformity of expansion and cycle time are worsened
Solution Approach 1:
The mandrel is divided into two separate mandrels (first mandrel and second mandrel) that can move independently relative to each other. This segmentation allows each mandrel to contact and expand different sections of the PEX tubing uniformly, solving the problem of non-uniform expansion that occurs with a single mandrel design.
2Productivity
If existing expansion tools are used, then the device complexity is maintained at current levels, but the cycle time increases to more than one second
Solution Approach 1:
The drive mechanism is designed to dynamically control the movement of the two mandrels, enabling them to move simultaneously in a coordinated manner. This dynamic control allows the expansion process to be completed rapidly within one second or less, significantly improving productivity compared to slower existing tools.
Solution Approach 2:
The two mandrels are configured to move continuously and simultaneously during the expansion process, maintaining constant contact with the PEX tubing throughout the cycle. This continuous action eliminates idle time and ensures the expansion is completed efficiently within the one-second cycle time target.
3Reliability
If expansion is not uniform, then the connection quality with fittings is worsened, but achieving uniform expansion would require more complex control mechanisms
Solution Approach 1:
By dividing the mandrel into two separate mandrels that can be independently controlled, the system achieves uniform expansion across different sections of the PEX tubing. This segmentation allows each mandrel to focus on expanding its designated section uniformly, ensuring high connection quality without requiring overly complex control mechanisms.
Solution Approach 2:
Each mandrel is designed with specific contact surfaces tailored to contact and expand particular sections of the PEX tubing. This local customization of the mandrel surfaces ensures that each region of the tubing receives the appropriate expansion force, resulting in uniform overall expansion and reliable fitting connections.
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
Facilitates rapid and uniform expansion of PEX tubing, enabling quick and secure fitting installation by minimizing cycle time and ensuring consistent expansion.
Implementation Method 1
The first contact surface and the second contact surface are engageable with the jaws to move the jaws from the closed position toward the expanded position in response to movement of the first mandrel and the second mandrel from the retracted position toward the extended position
Implementation Method 2
The PEX tube elastically recovers around the fitting to form a tight connection
Data Source
Figure 1
Figure 2~3
AI summary
An expansion tool includes a working element (200) configured to expand an end of a tube. The working element (200) includes a plurality of jaws (218) movable between a closed position and an expanded position. The expansion tool also includes first mandrel (50) with a first contact surface (94) and a second mandrel (310) coupled to the first mandrel (50). The second mandrel (310) has a second contact surface (319). The first mandrel (50) and the second mandrel (310) are movable together relative to the jaws (218) between a retracted position and an extended position. The first contact surface (94) and the second contact surface (319) are engageable with the jaws (218) to move the jaws (218) from the closed position toward the expanded position in response to movement of the first mandrel (50) and the second mandrel (310) from the retracted position toward the extended position.