Syringe Attachment Piece Chamfer Design
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Solution Overview
Problem
Syringes with existing designs often experience insufficient holding forces due to line-shaped contact between the clamping region and the radially set-back edge, leading to easy detachment during operation and sterilization, especially when the attachment piece is placed closer to the syringe cylinder, causing material stress and reduced friction.
Innovation Solution
The syringe design incorporates chamfers on both the clamping region and the radially set-back edge, creating a surface contact that enhances frictional forces, with the chamfers geometrically harmonized to optimize surface friction and maintain secure attachment, even under varying placement positions and sterilization conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the distal edge of the clamping region has an acute angle or right angle, then the attachment piece can be easily assembled, but the holding forces are insufficient and the attachment piece can slip off easily
Solution Approach 1:
Instead of having the clamping region edge engage with the flat surface of the set-back region, the invention inverts the engagement geometry by providing a chamfer on the set-back region that engages with a corresponding chamfer on the clamping region. This inversion creates surface contact rather than line contact, significantly increasing frictional forces and holding capability while maintaining ease of assembly.
Solution Approach 2:
The invention changes the geometric parameters of the engaging surfaces by introducing chamfers with specific angles (e.g., 45 degrees) on both the set-back region and the clamping region. This parameter change transforms the contact from a line contact (acute angle or right angle) to a surface contact, increasing the contact area and frictional forces, thereby improving holding force without compromising assembly ease.
2Reliability
If the attachment piece is placed closer to the syringe cylinder, then the connection is more secure, but material stress increases and holding forces decrease due to over-expansion
Solution Approach 1:
The chamfer geometry on the set-back region is designed with specific dimensional parameters (length, angle) that optimize the engagement zone. This parameter optimization ensures that the clamping region engages effectively without excessive expansion, reducing material stress while maintaining secure connection even when the attachment piece is positioned closer to the syringe cylinder.
3Reliability
If the clamping region is expanded considerably, then the attachment piece is held firmly, but during sterilization material relaxation occurs and holding forces are reduced
Solution Approach 1:
The chamfer design optimizes the engagement parameters to achieve firm holding without excessive expansion of the clamping region. By controlling the expansion within optimal limits through the chamfer geometry, the material remains below its glass transition temperature during sterilization, preventing irreversible relaxation and maintaining holding forces.
Solution Approach 2:
The chamfer engagement creates a buffered connection that accommodates thermal expansion and contraction during sterilization without causing excessive stress or relaxation. The geometric harmonization of the chamfers provides a cushioning effect that protects against material property changes during temperature cycling.
4Ease of manufacture
If the region set back in radial direction is configured as tapered, then manufacturing is easier, but the outside diameter variation causes uneven expansion and reduced friction
Solution Approach 1:
Instead of having the clamping region engage with the tapered surface of the set-back region (which would cause line contact and uneven expansion), the invention inverts the engagement by providing a chamfer on the set-back region that creates a localized engagement zone. This inversion ensures that the clamping region engages at a consistent diameter regardless of the overall taper, maintaining uniform friction forces.
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 enhanced surface contact and geometric harmonization of chamfers significantly increase holding forces, preventing accidental detachment during use and minimizing material stress and relaxation during sterilization, ensuring a secure and stable attachment of the attachment piece to the syringe body.
Implementation Method 1
The chamfer on the distal edge of the clamping region engages with the chamfer that is configured at the edge of the region that is set back in a radial direction... thereby creating surface contact and thus increasing the frictional forces
Implementation Method 2
When the attachment piece is placed onto the syringe in such a way that the clamping region engages with the region that is radially set back, there results an expansion of the clamping region in a radial direction in such a way that holding forces are introduced into the radially set-back region of the syringe
Data Source
AI summary
A syringe includes a syringe cylinder and a distal end designed as a syringe cone. The distal end comprises a region set back in a radial direction such that an edge extending in the circumferential direction is formed. The edge has a first chamfer, and comprises an attachment piece having a clamping region. Holding forces are introduced from the attachment piece via the clamping region in the region of the syringe set back in a radial direction. The clamping region comprises a distal edge. The the distal edge of the clamping region has a second chamfer.