Hollow Needle Cutting Edge Reduces Clamping Force
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Solution Overview
Problem
Hollow needles used for piercing sample vessel closures in laboratory automation devices face increased piercing force and clamping forces, leading to premature wear and potential contamination or clogging, as the larger diameter section requires significant force to pass through the closure and can cause the closure to be pulled off or contaminated.
Innovation Solution
A hollow needle design with a cylindrical profile featuring a first section, a second section of larger diameter, and a transition with cutting edges that reduce clamping forces by cutting open the closure, allowing for reduced lateral forces on the needle during piercing, with cutting edges distributed around the circumference and angled to compensate for asymmetrical loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hollow needle has a second section with larger diameter to enable effective piercing, then the piercing capability is improved, but the clamping forces and piercing force increase significantly
Solution Approach 1:
The cutting edges perform a preliminary action by cutting the closure material before the larger diameter second section needs to pass through. This pre-cutting creates an opening that allows the second section to pass with minimal clamping forces, resolving the contradiction between needing a large diameter for effective piercing and avoiding excessive clamping forces.
Solution Approach 2:
The transition region is segmented into multiple cutting edges distributed around the circumference. This segmentation allows the closure to be cut in a stepwise manner, distributing the cutting action and reducing the peak forces required compared to a single cutting action, thereby enabling the larger diameter section to pass through with reduced clamping forces.
2Reliability
If the hollow needle has a second section with larger diameter for effective piercing, then the piercing capability is improved, but the closure may be pulled off or pulled out together with the sample vessel
Solution Approach 1:
The cutting edges create a pre-cut opening in the closure before the larger diameter second section passes through. This preliminary cutting action ensures that the closure material is already separated along the piercing path, preventing the closure from being pulled off or detached when the needle is withdrawn, thus resolving the contradiction between effective piercing and closure detachment.
3Reliability
If the hollow needle has a second section with larger diameter, then the piercing capability is improved, but the mechanics of the device experience strain and wear
Solution Approach 1:
The cutting edges perform preliminary cutting to create an opening before the larger diameter second section passes through the closure. This preliminary action significantly reduces the force required for the second section to pass through, thereby reducing the mechanical strain and wear on the device mechanics while maintaining effective piercing capability.
4Reliability
If the hollow needle has a second section with larger diameter, then the piercing capability is improved, but material of the closure may be punched out causing clogging or contamination
Solution Approach 1:
The cutting edges perform a preliminary cutting action to cleanly separate the closure material along the piercing path before the larger diameter second section passes through. This pre-cutting prevents the closure material from being punched out or torn, thereby avoiding clogging of the needle or contamination of the sample while maintaining effective piercing capability.
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 design minimizes clamping forces during piercing, reducing the risk of closure detachment, contamination, and mechanical strain on the device, while ensuring efficient sample handling and reducing wear and tear on the device's mechanics.
Implementation Method 1
The cutting edge means that when the closure is pierced, the closure is further cut open by the cutting edge, which reduces the clamping forces acting laterally on the hollow needle
Data Source
AI summary
A hollow needle for piercing a closure of a sample vessel, wherein the hollow needle has a cylindrical hollow profile extending along a longitudinal axis and having a tip at a first end thereof, where the hollow needle has a first section that has a tip and a second section that has a larger diameter than the first section, and a transition between the first section and the second section has at least one cutting edge that extends from the first section to the second section.