Needle Delivery Device Linear Motion Drive Mechanism
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Solution Overview
Problem
Conventional needle delivery methods cause trauma to the skin due to high forces required to penetrate the outer layer, and existing devices are cumbersome and inefficient in delivering drugs at different depths without reinsertion.
Innovation Solution
A needle delivery device with a linearly movable drive mechanism and a contact member that minimizes rotational movement, combined with a control assembly and sensor for gradual force application and precise drug delivery at varying depths, utilizing a low friction surface and a motor-driven plunger mechanism for efficient drug administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the needle assembly rotates during insertion, then the drive mechanism can be simpler with fewer components, but the skin trauma increases due to non-concentric needle movement
Solution Approach 1:
The device separates the rotational drive function from the needle insertion function. The drive member rotates to provide driving force, while the needle assembly is constrained to move only linearly through the contact member, preventing rotation at the needle-skin interface and eliminating skin trauma caused by rotational movement.
2Productivity
If the needle insertion speed is increased to deliver dose rapidly, then the treatment time is reduced, but the skin trauma increases due to higher forces required to breach the outer layer
Solution Approach 1:
The drive mechanism dynamically adjusts the insertion speed profile. The control assembly varies the rotational speed of the drive member during insertion: slower speed when breaching the tough outer skin layer to minimize trauma, and faster speed once penetration is achieved to rapidly deliver the dose, thus optimizing both patient comfort and treatment efficiency.
3Loss of energy
If a low friction surface is used between drive member and contact member, then the drive mechanism efficiency improves, but the control over needle rotation becomes more challenging
Solution Approach 1:
The contact member has differentiated surface properties: a low friction surface facing the drive member to minimize energy loss and enable smooth rotational driving, and a high friction surface facing the needle assembly to ensure firm gripping and prevent any rotational movement of the needle. This local quality differentiation resolves the contradiction between reducing friction loss and maintaining control precision.
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 solution reduces skin trauma by applying low initial forces and increasing speed after penetration, allowing for accurate and efficient delivery of pharmaceuticals at different depths without reinsertion, enhancing user experience and reducing infection risks.
Implementation Method 1
the surface of the contact member abutting the drive member provides a low friction which prevents translation of the rotational movement of the drive member to the contact member
Implementation Method 2
the drive member includes a threaded shaft and the drive mechanism further includes a fixed drive plate, wherein the threaded shaft and the fixed drive plate are threadably engaged with one another
Data Source
AI summary
A needle delivery device (10) comprises a needle assembly (4, 5), a drive mechanism (2, 3) and a contact member (6). The drive mechanism (2, 3) includes a drive member (2) which is linearly moveable upon rotation of the drive member (2). The contact member (6) is positioned between and abutting the needle assembly (4, 5) and the drive member (2). The contact member (6) is configured to provide only linear motion to the needle assembly (4, 5) upon rotation of the drive member (2) so as to drive movement of the needle assembly (4, 5) between a distal and proximal direction relative to the needle delivery device (10).