Friction Fit Coupling Mechanism for Compact Medication Delivery
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Solution Overview
Problem
Existing medication delivery devices face challenges with space-efficient design and usability due to the size requirements for needle insertion and retraction mechanisms, as well as the need for efficient coupling mechanisms that allow relative rotation between parts, which are not adequately addressed by prior art solutions.
Innovation Solution
A medication delivery device featuring a friction fit arrangement with a one-way ratchet system that enables axial shifts and relative rotation, reducing the axial distance between components and allowing for efficient needle insertion and retraction without increasing the device's lateral dimensions, while maintaining a compact form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-way ratchet system is used for coupling, then unidirectional force transmission is achieved, but the device requires substantial torque and suffers from efficiency losses
Solution Approach 1:
The coupling mechanism transitions from a static ratchet system to a dynamic friction-fit system where the friction level can change during operation. The elastic element dynamically adjusts the friction fit between coupling members, allowing the system to switch between high-friction (coupled) and low-friction (decoupled) states, thereby reducing energy losses while maintaining reliable force transmission when needed.
2Loss of energy
If axial shifts are used to open/close ratchet system, then efficiency losses are reduced, but additional mechanisms like gearing or threading are required
Solution Approach 1:
The invention merges the coupling and decoupling functions into a single rotational motion of the drive mechanism. The friction-fit arrangement with elastic element allows the coupling members to naturally shift axially and engage/disengage through the rotation itself, eliminating the need for separate gearing or threading mechanisms while maintaining efficiency.
Solution Approach 2:
The elastic element automatically adjusts the friction fit between coupling members based on the rotational position and forces applied. The system self-regulates the coupling state without requiring external control mechanisms, reducing complexity while maintaining efficient operation.
3Ease of operation
If form-fit engagement is used to prevent rotation, then axial movement is allowed, but manual screwing is required for reservoir attachment
Solution Approach 1:
The invention replaces the manual screwing mechanism with an automated friction-fit system driven by the drive mechanism's rotation. The elastic element provides the necessary friction to prevent unwanted rotation while allowing axial movement, and the same rotational motion that drives medication delivery also automatically attaches the reservoir, eliminating manual intervention.
4Adaptability or versatility
If needle insertion mechanism is included, then subcutaneous delivery is enabled, but the device dimensions increase in the perpendicular direction
Solution Approach 1:
The invention reorients the needle insertion mechanism to operate in a direction parallel to the adhesive layer rather than perpendicular to it. This dimensional change allows the needle to be inserted at an angle, enabling subcutaneous delivery while maintaining a compact device thickness suitable for wearability.
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 provides a reliable and space-saving configuration for the coupling mechanism, enabling effective medication delivery while enhancing patient comfort and device usability by minimizing the device's size and complexity.
Implementation Method 1
The second part is in a friction fit engagement with respect to the housing, the friction fit engagement having a second frictional resistance
Implementation Method 2
A rotation of the drive mechanism in one rotation direction closes the one-way ratchet such that the first, second and third part rotate in unison in the one rotation direction
Implementation Method 3
The first part has a threaded engagement to a second part which is arranged along the rotation axis. The threaded engagement between the first part and the second part has a first frictional resistance
Data Source
Figure 1~2
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Figure 5
AI summary
A coupling mechanism for a medication delivery device which is embodied in a housing. The coupling mechanism comprises a first part having a longitudinal axis and which is axially fixed with respect to the housing and rotatable around the longitudinal axis, the first part having a gearing engagement to a second part which is arranged along the longitudinal axis, the gearing engagement having a first frictional resistance. The second part is axially moveable along the longitudinal axis, and directly or indirectly in a friction fit engagement with respect to the housing, the friction fit engagement having a second frictional resistance. The coupling mechanism is characterized by that the first frictional resistance is below the second frictional resistance such that a rotation of the first part in a first rotation direction axially moves the second part away from the first part along the longitudinal axis and a rotation in a second rotation direction which is opposite to the first rotation direction reduces the axial distance between the first and second part and/or axially moves the second part in coupling abutment with the first part.