Telescopic Piston Rod Assembly for Compact Medicament Delivery
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Solution Overview
Problem
Existing medicament delivery devices are too long to fit unobtrusively in a pocket or handbag due to their design, making them cumbersome for users with impaired vision and reduced dexterity, particularly those with diabetes who require insulin administration.
Innovation Solution
A medicament delivery device featuring a telescopic piston rod assembly with an input drive telescopically coupled to a plunger via an intermediate coupling, where the plunger and sleeves are axially but not rotationally movable, allowing for a compact design by minimizing the length of the telescopic piston rod assembly through progressive diameter reduction from the plunger to the input drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lead screw with threaded piston engagement is used to drive the medicament cartridge, then the driving action can effectively expel medicine, but the device length becomes at least twice the cartridge length, making it too long to fit unobtrusively in a pocket or handbag
Solution Approach 1:
The patent implements a telescopic piston rod assembly where multiple rod segments are nested within each other. The segments can extend axially to provide the necessary stroke length for driving the bung, then retract to minimize the overall device length for portability. This nesting approach allows the device to achieve both long stroke capability and compact storage dimensions.
Solution Approach 2:
The piston rod is divided into multiple telescopic segments that can extend and retract relative to each other. This segmentation allows the rod to achieve a long extended length for effective medicament expulsion while maintaining a short retracted length for pocketable dimensions, directly resolving the contradiction between driving effectiveness and portability.
2Length of moving object
If a telescopic piston rod is used to reduce device length, then the device becomes more portable, but the telescopic mechanism increases structural complexity
Solution Approach 1:
The telescopic piston rod assembly uses a nested structure where segments are housed within each other, providing a systematic way to manage the complexity of the telescopic mechanism while achieving compact dimensions.
3Length of moving object
If the device is made compact for portability, then it becomes easier to carry, but it may become difficult to use for users with impaired vision and reduced dexterity
Solution Approach 1:
The device incorporates an automatic drive mechanism with a motor that dynamically controls the telescopic piston rod extension and retraction. This dynamic automation eliminates the need for users to manually manipulate complex telescopic mechanisms, making the device easy to operate even for those with impaired vision and dexterity, while maintaining compact portability.
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 compact design enables a more portable medicament delivery device that is easier to use for individuals with impaired vision and reduced dexterity, allowing for efficient medicament dispensing while maintaining robustness and ease of operation.
Implementation Method 1
the lead screw is in threaded piston engagement with a drive mechanism that comprises a gear and electric motor. The rotational drive of the motor is translated into an axial force by the gear and threaded piston
Implementation Method 2
a telescopic piston rod assembly for driving a bung of a medicament container; and a drive mechanism for the telescopic piston rod assembly, wherein the telescopic piston rod assembly has an input drive telescopically coupled to a plunger
Implementation Method 3
a key for restraining rotation of the plunger relative to the housing
Data Source
Figure 1~4
Figure 5
Figure 6~8
AI summary
A medicament delivery device (1) comprises a housing (15), a telescopic piston rod assembly (12) for driving a bung (20) of a medicament container (9), and a drive mechanism (17) for the telescopic piston rod assembly. The telescopic piston rod assembly (12) has an input drive (23) telescopically coupled to a plunger (55) for driving the bung (20) via an intermediate coupling. The intermediate coupling comprises first and second cylinders (45, 49) telescopically coupled to one another. The plunger (55) is telescopically coupled to one of the first and second cylinders (45, 49) and the input drive (23) is telescopically coupled to the other cylinder. A key (14) is provided for restraining rotation of the plunger (55) relative to the housing (15) so that as the drive mechanism (17) drives the input drive, the plunger, first and second members and input drive telescopically expand or retract with respect to one another.