Syringe Cap Assembly with Deformable Mounting Portion
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Solution Overview
Problem
The existing syringe cap design often results in excessive load on the claw portion during assembly, leading to potential scrapping and easy detachment from the syringe nozzle, especially after sterilization processes.
Innovation Solution
A tubular cap design featuring a plate-shaped sealing member and a harder tubular cover member with specific geometrical features such as claw portions, column portions, and notch/recessed portions that deform to secure the cap without excessive load, preventing scrapping and detachment during assembly and sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cap is attached to the distal nozzle portion using a conventional design with claw portions, then the cap can be fixed to the syringe, but an excessive load is applied to the claw portion during assembly causing the claw portion to be scrapped and the cap to easily come off
Solution Approach 1:
The cap is divided into multiple functional segments: the cover member with claw portions for engagement, the sealing member for sealing, and the reinforcement structure. This segmentation allows each part to perform its specific function optimally while distributing the assembly load across multiple points rather than concentrating it on the claw portions alone.
Solution Approach 2:
The reinforcement structure is strategically positioned at specific locations on the cover member where stress concentration occurs during assembly. This local reinforcement provides additional structural support precisely where needed, strengthening the claw portions without requiring a complete redesign of the entire cap structure.
2Ease of manufacture
If the cap structure is simplified for easy manufacture, then manufacturing cost decreases, but the cap becomes more prone to detachment during sterilization and assembly
Solution Approach 1:
The cap employs an asymmetric structure where the cover member and sealing member have different geometries and material properties optimized for their specific functions. The cover member has a harder, more rigid structure for mechanical engagement, while the sealing member is softer for sealing, creating an asymmetric design that enhances reliability without significantly complicating manufacturing.
Solution Approach 2:
The sealing member is nested within the cover member, with the cover member providing structural support and the sealing member providing the sealing function. This nested configuration allows both components to work together in a compact arrangement that maintains reliability while being manufacturable using standard molding techniques.
3Stability of the object's composition
If the cap uses a harder material for the cover member to prevent deformation during sterilization, then sterilization resistance improves, but the assembly process may cause excessive stress on the claw portions
Solution Approach 1:
The cap is pre-assembled with the sealing member already positioned within the cover member before the final attachment to the syringe nozzle. This preliminary assembly allows the harder cover member to be properly positioned and oriented, reducing misalignment stresses during the final attachment process that would otherwise concentrate excessive force on the claw portions.
Solution Approach 2:
The cap design incorporates controlled flexibility in specific areas while maintaining overall rigidity. The reinforcement structure provides dynamic support that allows the cap to accommodate slight variations in assembly positioning without transmitting excessive stress to the claw portions, while still maintaining sufficient rigidity to resist deformation during sterilization.
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 cap securely attaches to the syringe nozzle, reducing the risk of detachment and maintaining stability during sterilization, thereby ensuring consistent pressure resistance and ease of removal without leakage or rattling issues.
Implementation Method 1
a plate-shaped sealing member (41) that has elasticity and seals a distal opening (49) of the distal nozzle portion (48)
Data Source
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AI summary
A syringe assembly (12A) includes: a plate-shaped seal member (41) that seals a distal opening (49) of a distal nozzle portion (48) of a syringe (24); and a tubular cover member (42). The cover member (42) has a base portion (56) and a mounting portion (58). The mounting portion (58) has two claw portions (62a, 62b), two first column portions (64) arranged on both sides of one of the two claw portions (62a, 62b), and two second column portions (66) arranged on both sides of the other of the two claw portions (62a, 62b). An outer peripheral portion of the mounting portion (58) has two outer peripheral notch portions (67). An inner peripheral portion of the mounting portion (58) has two inner peripheral recessed portions (74).