Dispenser Dose Counter Guide Mechanism
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Solution Overview
Problem
Existing dispensers for medicaments, such as metered-dose inhalers, face issues with manufacturing tolerances affecting performance, leading to unreliable dose counting and potential miscounting due to inconsistent container lengths and movement detection challenges.
Innovation Solution
A dispenser design featuring a counter driver guide with a protrusion and notch configuration to prevent rotation about the longitudinal axis, coupled with a drive mechanism that translates vertical movement into incremental rotation for accurate dose counting, ensuring reliable counting and preventing miscounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a counter driver is used to track doses dispensed, then dose counting capability is provided, but manufacturing tolerances cause rotation inconsistencies leading to miscounts
Solution Approach 1:
The patent transitions from detecting rotational position (2D angular measurement) to detecting linear reciprocating movement (1D linear measurement). The counter driver moves linearly along the longitudinal axis in response to actuation, and this linear displacement is converted to rotational movement of the counter via a drive mechanism. This dimensional change eliminates the problem of rotational inconsistencies caused by manufacturing tolerances.
Solution Approach 2:
The patent changes the fundamental parameter of movement detection from angular position to linear displacement. By measuring the linear reciprocating movement of the counter driver along the longitudinal axis rather than rotational angle, the system becomes insensitive to variations in container length and rotational positioning tolerances.
2Ease of operation
If the counter driver is allowed to rotate freely, then the drive mechanism can operate, but the counter may miscount due to unintended rotation
Solution Approach 1:
The patent extracts the unwanted rotational degree of freedom from the counter driver by introducing a guide feature. The guide protrusion and guide notch configuration removes the ability of the counter driver to rotate about the longitudinal axis, leaving only the desired linear reciprocating movement. This separation of movement modes ensures reliable counter operation.
Solution Approach 2:
The guide feature acts as an intermediary constraint between the counter driver and the drive mechanism. It mediates the movement of the counter driver by permitting linear reciprocating motion while preventing rotational motion, thereby ensuring that the drive mechanism receives only the intended input motion for accurate dose counting.
Data Source
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AI summary
The present invention relates to a dispenser (200) for dispensing a dose of a gaseous, gas borne or droplet substance from a substance source, the dispenser comprising: a body for receiving a substance source, the body having a mouthpiece; and a dose counter (203) for indicating a number of actuations of the dispenser corresponding to a number of doses dispensed from a substance source, or a number of doses remaining in a substance source, the dose counter comprising: a counter having indicia, the counter being rotatable within the body in increments about the longitudinal axis of the body; a counter driver (206) for driving the counter, the counter driver being arranged to be reciprocatably moveable within the body in the longitudinal axis in response to an actuation of the dispenser; and a drive mechanism (205) for rotating the counter, the drive mechanism being coupled to the counter driver and configured to rotate the counter in response to longitudinal movement of the counter driver, wherein the body comprises a counter driver guide (230) configured to guide the counter driver (206) in the body so as to prevent rotation of the counter driver in the longitudinal axis. Examplary means to prevent rotation is the counter guide (230) interacting with notched portion (220) on counter driver.