Rotatable Cannula Attachment With Detent Depth Control
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Solution Overview
Problem
Current devices for injecting botulinum toxin lack reliable and precise control over cannula depth and stability, leading to potential errors and complexity in administering the toxin effectively.
Innovation Solution
A rotatable attachment system with a proximal and distal part, featuring a detent mechanism and spiral groove, allowing for discrete holding positions and tactile/visual feedback, enabling precise control over cannula protrusion and depth adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a threaded connection with a scale is used to adjust cannula protrusion, then the extent of protrusion can be visually checked, but the retention of the distal part is poor when the cannula protrudes only slightly and discrete positions cannot be set
Solution Approach 1:
The patent implements tactile feedback through detent positions that provide distinct clickable stops during rotation, allowing the user to feel and confirm discrete depth settings. Visual feedback is provided through a scale that displays the corresponding depth value at each detent position, combining both tactile and visual confirmation for precise and reliable depth control.
Solution Approach 2:
The continuous rotational adjustment is segmented into discrete detent positions, where each position corresponds to a specific cannula protrusion depth. This segmentation provides stable, predetermined settings that improve retention and prevent continuous sliding, while the associated scale provides visual measurement for each segmented position.
2Measurement precision
If the entire syringe is moved relative to an attachment to adjust insertion depth, then depth control is achieved, but the device becomes very complex and prone to failure
Solution Approach 1:
The patent extracts the depth adjustment function from the entire syringe mechanism and isolates it to a simple rotatable attachment component. Instead of moving the whole syringe or using complex gear mechanisms, only the attachment needs to rotate relative to the syringe body, significantly simplifying the device while maintaining precise depth control capability.
3Stability of the object's composition
If discrete locking positions are provided for the distal part, then stable positions are achieved, but the setting can only be checked visually and not tactilely
Solution Approach 1:
The patent incorporates tactile feedback through the detent mechanism, where each locking position corresponds to a distinct clickable stop that the user can feel during rotation. This tactile confirmation allows the user to know when a discrete position is engaged without relying solely on visual inspection, improving ease of operation while maintaining stable locking positions.
Data Source
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AI summary
An attachment (1, 1a) for or on a device (100) for injecting a fluid into or under the skin (200), suitable, for example, for the injection of botulinum toxin into face muscles of a human patient, has: a proximal part (2, 2a) which can be coupled to the device (100) or is connected to the same, and which has a cannula (3). A distal part (4, 4a) surrounds the cannula (3) at least in sections and is rotatably movable with respect to the proximal part (2, 2a) and vice versa, so that one dimension (d3) of the projection of the cannula out of the distal part (2, 2a) is changeable. A discrete number of stopping positions is provided with respect to the rotatable movement, to which a different dimension of the projection of the cannula (3) out of the distal part (2, 2a) corresponds.