Medicament Dose Counter with Nested Count Wheels
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Solution Overview
Problem
Existing medicament dispensers lack a reliable and tamper-proof dose counter that can accurately count both aerosol and powdered medicament doses, with a focus on minimizing false counts and being easily reusable and recyclable.
Innovation Solution
A dose counter comprising a ratchet, a first count wheel, a second count wheel, and a kick wheel, where the first count wheel includes ratchet drive receipt elements and a fixed index tooth for intermittent meshing with the kick wheel, ensuring accurate counting and preventing reverse rotation, housed in a compact and reusable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a dose counter is designed to be compact and thin, then the housing extends upwards to a minor extent, but accommodating a large count range (at least 120 counts) in such a compact space becomes difficult
Solution Approach 1:
The counter wheels are arranged concentrically with the first count wheel having a smaller diameter than the second count wheel, allowing both wheels to be nested within the same housing space. This nesting arrangement enables a large count range to be accommodated in a compact, thin housing without requiring excessive upward extension.
Solution Approach 2:
Instead of extending the housing upwards to accommodate multiple count wheels vertically, the invention arranges the count wheels in a horizontal plane with different diameters. This dimensional change allows the counter to achieve a large count range while maintaining a compact, thin profile in the vertical direction.
2Device complexity
If the counter wheels are arranged to rotate about a common axis, then the structure is simplified, but the mechanism becomes more susceptible to tampering and false counts
Solution Approach 1:
The counter mechanism is segmented into multiple independently rotatable count wheels (first and second count wheels) with different functions. The first count wheel counts individual doses while the second count wheel counts groups of ten doses. This segmentation allows each wheel to have specialized anti-tampering features while maintaining overall structural simplicity.
Solution Approach 2:
A ratchet mechanism acts as an intermediary between the drive source and the count wheels, providing controlled unidirectional rotation and preventing reverse rotation that could indicate tampering. The ratchet allows the first count wheel to rotate only in the counting direction, enhancing reliability while maintaining the common axis arrangement.
3Measurement precision
If the counter is designed to register counts only when medicament is provided to the patient, then false counts are minimized, but the mechanism becomes more complex
Solution Approach 1:
The counter mechanism is driven directly by the medicament dispenser's own operation through the ratchet drive. Each actuation of the dispenser automatically advances the ratchet, which in turn rotates the first count wheel to register a count. This self-service arrangement ensures that counts are registered only when actual medicament delivery occurs, minimizing false counts without requiring external monitoring systems.
Solution Approach 2:
The counting mechanism operates periodically with each medicament delivery event. The ratchet advance and count wheel rotation occur in discrete, periodic steps synchronized with dispenser actuation. This periodic action ensures that each count corresponds to an actual dose delivery, improving measurement precision while maintaining relatively simple mechanism design.
4Ease of manufacture
If the counter components are designed for re-use and recycling, then manufacturing costs are reduced, but ensuring tamper-proof operation becomes more difficult
Solution Approach 1:
The counter housing and components are designed as universal, reusable units that can be removed and replaced between different medicament dispensers. The standardized interface and robust construction allow the same counter assembly to serve multiple dispensers, reducing manufacturing costs while maintaining anti-tampering features through consistent design across all units.
Solution Approach 2:
The ratchet mechanism incorporates built-in anti-tampering features that are activated automatically upon any attempt at manipulation. The resilient pawl and ratchet teeth are designed to detect and respond to reverse rotation attempts before significant tampering can occur, providing beforehand protection that maintains reliability even in reusable components.
Data Source
AI summary
A dose counter for use with a medicament dispenser which comprises a ratchet; a first count wheel arranged to rotate about a first axis of rotation, the first count wheel including one or more ratchet drive receipt elements arranged thereon for receipt of drive from the ratchet to rotate the first count wheel about the first axis of rotation; a second count wheel arranged to rotate about the first axis of rotation, the second count wheel including a set of teeth arranged annularly thereon; and a kick wheel arranged to rotate about a second axis of rotation offset from the first axis of rotation, the kick wheel including a set of kick teeth arranged annularly thereon and in meshed relationship with the teeth of the second count wheel such that rotary motion of the kick wheel results in rotary motion of the second count wheel is described.