External Drug Pump Threaded Drive for Sterile Linear Dosing
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Solution Overview
Problem
Existing external drug pumps face challenges in efficiently delivering substances like insulin and other large molecules subcutaneously, with limitations in rotational mechanics and sterility maintenance, particularly in ensuring the stopper and threaded elements do not rotate during administration, and in providing a convenient and easy-to-use system for patients.
Innovation Solution
A vial system with first and second threaded elements, where the first element is rotatable but immobile linearly, and the second element is non-rotatable, coupled to a stopper, allowing linear advancement without rotation, integrated with a housing base and motor control for basal and bolus administration, and a skin-piercing mechanism for easy needle insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threaded element is used to advance the stopper, then the substance can be delivered controllably, but the threaded element and stopper may rotate during administration compromising sterility
Solution Approach 1:
Instead of rotating the stopper directly, the patent inverts the approach by having the stopper rotate while the threaded element remains stationary. The stopper's rotation is constrained by friction against the vial wall, while the threaded element's linear motion is constrained by a constraint element, achieving sterile delivery without compromising either control or sterility.
Solution Approach 2:
The patent introduces a constraint element as an intermediary between the threaded element and the vial. This constraint element prevents the threaded element from rotating by engaging with the vial wall, allowing the stopper to rotate freely while the threaded element only moves linearly, thus maintaining sterility and enabling controlled delivery.
2Productivity
If the stopper is advanced linearly to deliver substance, then delivery control is improved, but the mechanism becomes complex requiring separate rotational and linear constraints
Solution Approach 1:
The patent merges the rotational and linear constraint functions into a single integrated mechanism. The constraint element simultaneously prevents rotation of the threaded element while allowing linear motion, and the friction between the stopper and vial wall simultaneously enables stopper rotation while preventing threaded element rotation, simplifying the overall mechanism.
Solution Approach 2:
The system utilizes self-generated friction between the stopper and vial wall to control rotation, eliminating the need for additional friction control mechanisms. The natural friction characteristics of the materials are harnessed to achieve the desired rotational control, reducing mechanism complexity.
3Extent of automation
If a motor is used to rotate the threaded element, then automated delivery is achieved, but the device size and complexity increase
Solution Approach 1:
The motor serves multiple functions: it rotates the threaded element to advance the stopper, and through the constraint element mechanism, it also controls the rate of substance delivery. The single motor drives the entire delivery system without requiring separate actuators for rotation and linear motion, reducing overall device complexity.
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
Enables efficient and controlled delivery of substances subcutaneously, maintaining sterility and user convenience by preventing stopper and threaded element rotation, facilitating easy insertion and retraction of needles, and allowing for basal and bolus administration with a compact and reusable design.
Implementation Method 1
first and second threaded elements (e.g., a screw and a nut) that are threadedly coupled to each other. The first threaded element is rotatable with respect to the vial... The first threaded element, by rotating, is configured to linearly advance the stopper and at least the distal end of the second threaded element
Implementation Method 2
The stopper impedes rotation of the second threaded element. For example, friction between the stopper and the inside of the vial impedes rotation of the second threaded element
Data Source
AI summary
Apparatus is described for administering a substance to a subject. A vial contains the substance and a stopper is disposed within the vial and is slidably coupled to the vial. A first threaded element is (a) rotatable with respect to the vial and (b) substantially immobile proximally with respect to the vial during rotation of the first threaded element. A second threaded element is threadedly coupled to the first threaded element. At least a distal end of the second threaded element is substantially non-rotatable with respect to the vial, and the distal end of the second threaded element defines a coupling portion that couples the second threaded element to the stopper. The first threaded element, by rotating, linearly advances the stopper and at least the distal end of the second threaded element toward a distal end of the vial. Other embodiments are also described.