Plunger Rod Guide-and-Stop Elements for Dose Volume Adjustment
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Solution Overview
Problem
Existing medicament delivery devices face challenges in handling varying medicament doses for different patients, as they often require modification or additional complex components to accommodate different container sizes, leading to increased costs and complexity.
Innovation Solution
A medicament delivery device with a housing that accommodates a container holder and a power unit comprising a force element and plunger rod, featuring guide-and-stop elements to adjust the linear distance of the plunger rod's movement, allowing for customizable dose volumes without altering the device's structure, and includes a medicament delivery member cover for safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the device is designed to handle a certain container size with a fixed drive mechanism, then the device structure is simple, but it cannot accommodate different dose volumes for different patients
Solution Approach 1:
The plunger rod is designed with an adjustable linear travel distance through guide-and-stop elements. The stop element can be positioned at different locations along the guide element, allowing the plunger rod to move different distances to deliver different dose volumes. This dynamic adjustment capability enables the device to handle various dose requirements without requiring multiple fixed designs.
Solution Approach 2:
The invention changes the parameter of plunger rod travel distance to accommodate different dose volumes. By adjusting the position of the stop element relative to the guide element, the linear distance the plunger rod can move is varied, thereby delivering different volumes of medicament from the same container size.
2Adaptability or versatility
If a dose setting mechanism is added to deliver different doses, then different dose volumes can be delivered, but the device becomes more complicated and expensive to manufacture
Solution Approach 1:
The dose adjustment function is segmented into simple, discrete components: a guide element with marked positions and a stop element that can be positioned at different locations. This segmentation avoids the need for complex integrated dose setting mechanisms while achieving the same functional result of delivering different dose volumes.
Solution Approach 2:
The guide-and-stop element assembly is designed as a simple, low-cost component that can be easily manufactured and potentially disposed of with the device. This simple mechanical solution is much cheaper to manufacture than complex electronic or mechanical dose setting mechanisms.
3Adaptability or versatility
If the plunger rod travels the full length of the container, then the entire medicament volume is delivered, but it cannot accommodate partial dose deliveries for different patient requirements
Solution Approach 1:
The stop element can be positioned at different locations along the guide element before use, allowing the plunger rod to travel only the necessary distance to deliver the required partial dose. This dynamic positioning enables flexible dose adjustment while maintaining simple operation - the user simply sets the stop position and activates the device.
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 flexible delivery of different medicament doses by adjusting the plunger rod's travel length, simplifying device assembly and reducing manufacturing complexity, while ensuring safe needle protection and minimizing accidental needle sticks.
Implementation Method 1
a force element and a plunger rod, wherein the plunger rod is arranged to, upon activation, move linearly in the proximal direction by the linear force from the force element
Data Source
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AI summary
The present invention relates to a medicament delivery device comprising a housing (10, 12), which housing (10, 12) is arranged to accommodate a medicament container (20), which medicament container (20) comprises a medicament delivery member (134); a power unit (74) interactively connected to the housing comprises a force element (82) and a plunger rod (76) which is arranged to, upon activation, move linearly in the proximal direction and act on said medicament container (20) for expelling a dose of medicament through said medicament delivery member (134); and a holding member (56) connected to said power unit and to said container holder. The invention is characterised in that the plunger rod comprises at least one first guide-and-stop element configured to interact with at least one second guide-and-stop element on said a holding member for limiting the linear distance the plunger rod (76) is capable of moving during expelling of medicament and which distance corresponds to a dose volume.