Luer Lock Syringe Reinforcing Ribs Cyclic Olefin Resin
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Solution Overview
Problem
Syringes with Luer lock connections made of cyclic olefin resin are prone to cracking and failure under high torque and pressure, especially when used with non-standard connectors, leading to instability and potential leakage, particularly with highly viscous medications and after autoclaving.
Innovation Solution
A syringe design featuring a one-piece Luer lock connection with axially extending reinforcing ribs on the Luer collar, a rounded transition to the frustoconical section, and an annular recess, which increases rigidity and deflects stress cracks, ensuring a stable and tight connection while being producible by injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Luer collar is made from cyclic olefin resin to ensure chemical resistance and sterility, then the syringe meets medical standards, but the Luer collar becomes brittle and susceptible to cracking under high torque
Solution Approach 1:
The patent applies composite material design by integrating the Luer collar with the syringe body in a one-piece construction made from cyclic olefin resin. This monolithic structure eliminates weak points at junctions and distributes stress throughout the integrated component, preventing crack propagation while maintaining the chemical resistance and sterility properties of the cyclic olefin resin material.
Solution Approach 2:
The patent introduces structural segmentation through reinforcing ribs that are integrally formed with the Luer collar. These ribs create internal stress distribution zones that segment the load path, preventing crack propagation through the collar wall while maintaining the overall integrity of the one-piece construction.
2Strength
If a connector is tightened with excessive torque to ensure a tight connection, then the connection strength increases, but stress cracks develop in the Luer collar and Luer cone
Solution Approach 1:
The patent implements beforehand cushioning by designing the Luer collar with integrated reinforcing ribs that pre-position structural support elements within the collar wall. These ribs are formed as part of the one-piece construction, creating internal stress distribution pathways that cushion against excessive torque loads before cracks can initiate or propagate.
Solution Approach 2:
The patent applies parameter changes by modifying the structural geometry of the Luer collar through the addition of reinforcing ribs with specific dimensions. The ribs have a defined radial extent and axial length that optimize the moment of inertia and stress distribution, allowing the collar to withstand higher torque values without exceeding the fracture strength of the cyclic olefin resin material.
3Strength
If the wall thickness of the Luer collar is increased to prevent cracking, then the connection stability improves, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent applies local quality by strategically placing reinforcing ribs at specific locations within the Luer collar structure rather than uniformly increasing wall thickness throughout. The ribs are positioned to provide maximum structural reinforcement where stress concentrations occur, while maintaining thinner wall sections in areas where full reinforcement is unnecessary, thus optimizing both strength and manufacturability.
Solution Approach 2:
The patent resolves the manufacturing contradiction by transitioning from a two-dimensional wall thickness parameter to a three-dimensional structural solution. Instead of simply increasing wall thickness uniformly, the reinforcing ribs add dimensional complexity in the radial and axial directions, creating a lattice-like internal structure that provides enhanced moment of inertia and crack resistance while maintaining overall dimensional constraints suitable for injection molding.
4Adaptability or versatility
If non-standard connectors are used to meet diverse medical application needs, then the adaptability increases, but the risk of excessive force and cracking increases
Solution Approach 1:
The patent applies universality by designing the Luer collar with a standardized external geometry that conforms to ISO 594-1 specifications, ensuring compatibility with all standard Luer connectors. The integrated reinforcing ribs provide universal structural support that handles the full range of torque values encountered with different connector types, making the collar equally reliable whether used with standard or non-standard connectors.
Data Source
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AI summary
The invention relates to a syringe (1) having a syringe body (2) with a cylindrical section (3) and a cone-shaped section (4) connected thereto, a luer-lock-connector (10) which comprises a luer collar (11) having an inner thread (12) and a luer cone (15) having a through channel (19). The syringe body (2) and the luer lock connector (10) are designed as a single piece and are made from a cyclic olefin resin, the luer collar (11) has reinforcing ribs (18) on its outer side.