Fluid Delivery Pen Dose Setting Mechanism with Variable Audible Feedback
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Solution Overview
Problem
Existing fluid delivery pen devices lack accurate and easy dose setting for patients with poor vision or hearing, and they often result in fluid wastage due to inability to indicate the remaining amount in the cartridge, leading to incorrect dose delivery.
Innovation Solution
A fluid delivery pen with a dose setting mechanism that produces varying sound audibility for dose setting and reduction, an end-of-dose indication without rotatable components, and reduced friction for easier injection, ensuring all fluid is delivered and preventing wastage by indicating the remaining amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a prior art dose setting mechanism with uniform ratchet clicks is used, then the device structure is simple, but visually and hearing-impaired patients cannot accurately distinguish between dose setting and dose reduction
Solution Approach 1:
The patent applies local quality by creating different auditory characteristics at different stages of the same dosing operation. The ratchet mechanism produces a first audible click characteristic when setting the dose and a second audible click characteristic when reducing the dose, allowing patients to distinguish between these operations through sound alone without adding complex visual or electronic components.
2Loss of substance
If no end-of-dose indication mechanism is provided, then the device structure is simple, but fluid wastage occurs due to inability to indicate remaining amount in cartridge
Solution Approach 1:
The end-of-dose indication mechanism utilizes the existing ratchet mechanism and dose setting member to provide self-service indication. When the dose setting member returns to the zero position after dose delivery, the ratchet produces an audible click that automatically indicates the cartridge is empty, eliminating the need for separate sensors, displays, or complex indication systems.
3Reliability
If a rotatable component with threaded features is used for end of dose mechanism, then the mechanism can indicate remaining fluid, but the device complexity increases and reliability decreases
Solution Approach 1:
The patent merges the end-of-dose indication function with the existing dose setting and ratchet mechanisms. The same ratchet that provides tactile and auditory feedback during dose setting also provides the end-of-dose indication when the dose setting member returns to zero, eliminating the need for separate rotatable components or threaded features dedicated to end-of-dose detection.
4Ease of operation
If high friction is present in the drive mechanism, then the structural strength is sufficient, but the ease of injection is reduced requiring higher injection force
Solution Approach 1:
The patent applies dynamics by using a cam mechanism that transforms the injection force application. The cam profile is designed to provide mechanical advantage during the injection stroke, dynamically adjusting the force transmission to reduce the peak force required from the patient while maintaining sufficient drive mechanism strength through the cam's structural design.
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 pen provides accurate and easy dose delivery with audible feedback for visually and hearing-impaired users, minimizing fluid wastage by ensuring all medication is used and preventing over-dosing.
Implementation Method 1
the ratchet cap comprises a ratchet and ratchet teeth, the mating of ratchet with ratchet teeth produce a click
Implementation Method 2
the hollow piston rod has a helical thread on an inner surface; the drive shaft has a helical rib on an outer surface; the helical thread of the piston rod mates with the helical rib of the drive shaft
Implementation Method 3
The thumb pad may be located on a proximal end of the ratchet cap
Data Source
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AI summary
The fluid delivery pen of the present invention has a reduced dose setting friction mechanism which may produce a sound of higher audibility for each click corresponding to one unit dose set using a dose setting mechanism and also produces a sound of lower audibility than the former for each click when the set dose is reduced using the dose setting mechanism. The fluid delivery pen driving mechanism of the present invention has an indication to an end of dose of fluid in a cartridge.