Dose Divider Syringe Plunger with Rotatable Abutment Surfaces
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Solution Overview
Problem
Existing syringes struggle with accurate delineation of multiple dose ranges, interfere with filling empty syringes, and are complex or expensive to manufacture, limiting their usability and efficiency in delivering precise medication doses.
Innovation Solution
A syringe design featuring a plunger with a dose divider that includes first and second abutment surfaces, allowing for axial and rotational adjustments to provide variable tactile feedback, enabling accurate delivery of multiple doses without requiring rotation of the plunger during filling and using reusable, cost-effective components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dose limiting housing with two axial bearing surfaces is used, then two distinct ranges of plunger travel can be delineated, but no more than two distinct ranges of plunger travel can be delineated
Solution Approach 1:
The dose divider is segmented into multiple dose division elements (first, second, third elements) arranged axially along the plunger rod. Each element has bearing surfaces that interact with the barrel flange to define different dose ranges, enabling delineation of multiple distinct plunger travel ranges beyond two
Solution Approach 2:
The invention transitions from a single housing with two bearing surfaces to multiple dose division elements arranged axially along the plunger rod. This adds the axial dimension to the design, allowing each element to define a separate dose range while maintaining interaction with the same barrel flange through rotational positioning
2Productivity
If stroke stops are frangible about a weakening line, then each broken stroke stop enables forward movement of the impelling plunger, but the stroke stops are inherently non-reusable
Solution Approach 1:
The dose division elements are designed to be rotatable about the longitudinal axis of the plunger rod, transitioning between an interfering position (where bearing surfaces contact the barrel flange to limit plunger travel) and a non-interfering position (where they allow full plunger movement). This dynamic repositioning enables reusability while maintaining sequential dose administration capability
3Measurement precision
If plunger stop surfaces have complex shapes, then predetermined volumes can be metered, but the stop surfaces are difficult or expensive to manufacture
Solution Approach 1:
The invention achieves precise volume metering by changing the axial position of bearing surfaces on rotatable dose division elements rather than using complex stop surface geometries. The bearing surfaces are simple planar or curved surfaces that contact the barrel flange, and precision is achieved through controlled axial positioning and rotation of the elements along the plunger rod
4Ease of operation
If stop mechanism is coupled by a hinge, then travel of plunger can be controlled, but no more than two distinct ranges of plunger travel can be delineated
Solution Approach 1:
The single hinged stop mechanism is segmented into multiple independent dose division elements (first, second, third elements) that can be independently positioned axially along the plunger rod. Each element can be rotated to an interfering position to define a specific dose range, enabling control of multiple distinct plunger travel ranges rather than just two
Data Source
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AI summary
A syringe includes a barrel with an internal surface defining an internal bore therein, a plunger disposed within the internal bore of the barrel, and a dose divider disposed on the plunger. The dose divider includes a first end, a first abutment surface, and a second abutment surface. The first abutment surface is spaced apart from the first end in the axial direction by a first axial distance, and the second abutment surface is spaced apart from the first end in the axial direction by a second axial distance. The second abutment surface is spaced apart from the longitudinal axis of the plunger by a first radial distance, and the first radial distance is greater than a radial dimension from a longitudinal axis of the barrel to the internal surface of the barrel near a proximal end of the barrel.