Medicament Delivery Device with Segmented Plunger Rod
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Solution Overview
Problem
Existing medicament delivery devices face challenges in accuracy and ergonomics when delivering multiple small, predetermined quantities of medicament in a stepwise mode, particularly due to high forces required for viscous substances and difficulties in delivering precise small doses.
Innovation Solution
A device with a container, pressure means, and driving mechanism featuring an energy accumulating member, nut, and driver, along with a manually operated push button for ergonomic handling, allowing stepwise pressure application and precise dose delivery through a threaded plunger rod and pinion gearing system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spring means are used to exert pressure on the medicament for delivering a specific dose, then the delivery of multiple specified quantities is achieved, but the friction between the resilient stopper and the inner surface of the container increases the force required
Solution Approach 1:
The device divides the total medicament volume into multiple predetermined doses by segmenting the plunger rod into sections corresponding to each dose. Each section can be independently actuated to deliver a specific quantity, allowing multiple specified quantities to be delivered without requiring excessive force for each individual dose.
Solution Approach 2:
A resilient member (spring) is introduced as an intermediary element between the actuator and the plunger rod. This spring stores energy when compressed and releases it to push the plunger rod, reducing the direct force requirement from the operator while still achieving the necessary pressure to deliver the medicament through the needle.
2Adaptability or versatility
If a normal type of syringe is used for manual injection of high viscosity medicament, then the medicament can be delivered, but the large forces required and many small injections make the treatment tiresome for the operator
Solution Approach 1:
The device is pre-loaded with a predetermined volume of medicament in the container, and the plunger rod is positioned to deliver multiple specified quantities. This preliminary preparation allows the operator to administer multiple doses without repeatedly loading the syringe or manually adjusting the volume, reducing fatigue while maintaining adaptability for high viscosity substances.
Solution Approach 2:
The device incorporates a movable plunger rod that can be actuated in a controlled manner to deliver multiple predetermined doses. The dynamic mechanism allows for precise control of each dose delivery, making the administration of multiple small injections less tedious while maintaining the ability to handle high viscosity medicament.
3Reliability
If a non-rotatable plunger rod with stop and release toothed unit is used, then the device can maintain the plunger in a stopped position, but the gearing is not adapted for delivering very small doses accurately
Solution Approach 1:
The plunger rod is made rotatable instead of non-rotatable, adding a rotational dimension to the linear pushing motion. This rotation allows for more precise control of the plunger's position and movement, enabling accurate delivery of very small doses while still maintaining the ability to stop and release at predetermined positions through the toothed unit.
4Productivity
If the actuation button is not fully depressed in multi-dose injection devices, then smaller doses cannot be delivered, but the mechanism for delivering multiple specified quantities is compromised
Solution Approach 1:
The plunger rod is segmented into multiple sections, each corresponding to a predetermined dose. The actuation button is designed to work with this segmentation, allowing for precise delivery of smaller doses by activating specific segments. This segmentation ensures that even small doses can be delivered accurately without compromising the ability to deliver multiple specified quantities.
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 accurate and ergonomic delivery of small doses, reducing operator fatigue and improving precision for delivering medicaments in the range of 0.01 ml to 0.005 ml per step, suitable for both high and low viscosity substances.
Implementation Method 1
a threaded plunger rod arranged to interact with said driving means for pushing said movable wall part forwardly
Implementation Method 2
a driver for driving said pressure means... wherein said activation means are capable of interacting with said driving means in a stepwise mode
Data Source
AI summary
The present invention relates to a device for expelling a predetermined quantity of medicament comprising driving means comprising an energy-accumulating member, a nut, and a driver for driving a pressure means; and activation means for activating said driving means wherein said pressure means comprises a movable wall part arranged inside a 2 container and a threaded plunger rod arranged to interact with said driving means for pushing said movable wall part forwardly, and wherein said activation means comprises a manually operated push button arranged on the front end of the device for promoting an ergonomic handling of the device and wherein said activation means are capable of interacting with said driving means in a stepwise mode; such that each time said push button is depressed said pressure means moves an step exerting pressure on the medicament inside the container and expelling a predetermined quantity of the medicament through the opening.