Cutting Element for Retracting Needle Syringe Activation
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Solution Overview
Problem
Existing retracting needle syringes face challenges in consistently and safely retracting the needle into the syringe barrel, often requiring a broad range of forces due to varying designs, which can lead to inconsistent activation and potential safety risks during needle disposal.
Innovation Solution
A cutting element with a cylindrically shaped body and distally projecting tapered teeth, featuring a beveled cutting edge and concave cutting edges, is designed to cut through the plunger and support structures, allowing for consistent and safe retraction of the needle with reduced activation forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a cutting element with tapered teeth and beveled edges is used, then the activation force required for needle retraction is reduced and becomes more consistent, but the manufacturing complexity of the cutting element increases
Solution Approach 1:
The cutting element is pre-formed during manufacturing with tapered teeth and beveled edges already integrated into the structure. This preliminary formation of the cutting geometry eliminates the need for post-manufacturing sharpening operations and ensures consistent activation forces from the start, resolving the contradiction between reduced activation force and manufacturing complexity
Solution Approach 2:
The cutting element geometry is optimized with specific parameters including tapered tooth profiles, beveled edges, and controlled radii. These parameter changes in the cutting element design enable consistent cutting performance with lower activation forces while maintaining manufacturability through precise but achievable geometric specifications
2Ease of manufacture
If a cutting element requiring post-forming sharpening and heat treatment is used, then the initial manufacturing is simpler, but the production time and additional processing steps increase
Solution Approach 1:
The cutting element is pre-formed during the primary manufacturing process with the final cutting geometry already established. The tapered teeth and beveled edges are created in-situ during forming, eliminating subsequent sharpening and heat treatment operations. This preliminary action resolves the contradiction by maintaining initial manufacturing simplicity while dramatically reducing production time through elimination of additional processing steps
3Device complexity
If dislodgeable elements or frangible barriers are used to allow needle retraction, then the structure can be simpler, but the forces required to activate retraction vary broadly between syringes
Solution Approach 1:
The cutting element features localized high-strength regions with specific geometric characteristics (tapered teeth, beveled edges) at the cutting interface, while the overall structure remains integrated and relatively simple. This local quality enhancement at the cutting surface ensures consistent activation forces without requiring complex overall structural changes, resolving the contradiction between structural simplicity and activation consistency
Solution Approach 2:
The cutting element geometry is optimized with specific parameters including tooth taper angles, edge bevel dimensions, and radius values that control the cutting characteristics. These parameter optimizations enable reliable and consistent activation forces across all syringes while maintaining a relatively simple integrated structure, resolving the contradiction between device complexity and reliability
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 cutting element provides a more consistent and safer mechanism for needle retraction, minimizing the forces required for activation and enhancing user safety by using a piercing and shearing mechanism instead of chopping, thus reducing the need for post-forming sharpening and heat treatment.
Implementation Method 1
The cutting element provides a more consistent and safer mechanism for needle retraction, minimizing the forces required for activation and enhancing user safety by using a piercing and shearing mechanism instead of chopping
Data Source
AI summary
A cutting element for a retracting needle syringe having a plunger with a cuttable distal end and a spring biased needle held by a cuttable support and a cutting element capable of cutting the cuttable distal end and the cuttable support includes a body portion having a proximal end, a distal end side wall therebetween and a passageway therethrough. The distal end of the body portion includes a cutting edge and a raised distally projecting tapered cutting tooth having distally converging edges. At least one tooth edge includes a sharp side wall for cutting the distal end of the plunger and the needle support.