Inhaler Ratchet Ring Mechanism for Incremental Torque Loading
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Solution Overview
Problem
Conventional drug inhalers require high torque for loading, which can be difficult for patients with limited strength or dexterity, and may result in premature activation and partial dose release, leading to incorrect dose counting.
Innovation Solution
A ratchet mechanism with a ratchet ring and chassis teeth configuration that allows incremental loading and resiliently holds back high loading torque, enabling patients to pause and complete the loading process with minimal force, preventing premature activation and dose undercounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high torque is applied to load the inhaler, then the inhaler can be fully loaded, but it becomes impossible for patients with limited strength or dexterity to operate
Solution Approach 1:
The ratchet mechanism divides the continuous rotational loading motion into discrete incremental steps. Each tooth engagement represents a discrete step in the loading process, allowing the user to apply torque in manageable increments rather than requiring a single high-torque application. This segmentation enables patients with limited strength to complete loading by accumulating small rotational increments.
Solution Approach 2:
The ratchet mechanism enables periodic or intermittent application of torque during the loading process. The user can pause between tooth engagements, applying torque periodically rather than continuously. This periodic action allows patients to rest between applications and complete loading over multiple smaller efforts rather than requiring sustained high torque.
2Ease of operation
If the inhaler is released before attaining the fully loaded state, then the patient can pause the twist action, but the inhaler activates in a premature state and releases a partial dose
Solution Approach 1:
The ratchet teeth and spring mechanism create a preliminary counter-action that prevents reverse rotation. When the user releases the inhaler during loading, the engaged ratchet teeth physically block any backward movement that would trigger premature activation. The spring maintains constant pressure on the teeth to ensure the locking action is always engaged, preventing accidental partial dose release.
Solution Approach 2:
The ratchet mechanism acts as an intermediary between the user's twisting action and the activation mechanism. It decouples the loading motion from the activation trigger, allowing the user to pause at any point during loading without directly activating the dose release. The ratchet teeth serve as the intermediary element that translates rotational motion into a controlled, non-reversible loading process.
3Ease of operation
If the inhaler is released before full loading, then the patient can take a break, but the partial dose is wasted and not registered by the counter mechanism
Solution Approach 1:
The ratchet mechanism prevents the harmful action of reverse rotation that would cause premature activation and waste medication. By engaging the teeth in the direction of loading and blocking reverse motion, the mechanism ensures that any pause during loading does not result in partial dose release. This preliminary anti-action against reverse rotation protects the medication from being wasted.
Solution Approach 2:
The spring-loaded ratchet mechanism provides a cushioning effect that absorbs any accidental reverse forces or pauses during loading. The spring maintains engagement pressure on the teeth, creating a buffer that prevents unintended activation. This beforehand cushioning ensures that even if the user releases the inhaler temporarily, the mechanism remains protected against premature dose release.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Disclosed is a ratchet mechanism having ratchet ring and a chassis. The ratchet ring is rotatable about an axis relative to the chassis, with a general direction of rotation determined by teeth of the ratchet mechanism. The ratchet ring has a first set of teeth arranged regularly around the ratchet ring and protruding in a first axial direction from the ratchet ring and a second set of teeth arranged regularly around the ratchet ring and protruding in a second opposite axial direction from the ratchet ring. The chassis has a third set of teeth arranged regularly and protruding in the second axial direction and generally opposed to the first set of teeth, and a fourth set of teeth arranged regularly and protruding in the first axial direction and generally opposed to the second set of teeth.