Cam-Controlled Needle Access Device for Repeatable Penetration
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Solution Overview
Problem
Existing access devices for injections and infusions lack precision and repeatability, posing risks for both patients and users, especially when administered by untrained individuals.
Innovation Solution
An access device with a base and a movably mounted needle that can be controlled between fully retracted and maximally extended positions, featuring a locking mechanism and cam system to ensure accurate penetration depth and minimize discomfort, allowing for precise and repeatable injections without requiring user interaction for needle retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a movable needle mechanism is used to enable retraction, then safety and ease of operation are improved, but device complexity increases
Solution Approach 1:
The needle is pre-loaded in a retracted position within the hub, and the spring is pre-compressed to provide automatic retraction force. The cam mechanism is pre-configured with its profile to automatically engage and disengage at the correct moments during insertion and removal, eliminating the need for manual retraction operations.
Solution Approach 2:
The spring-loaded cam mechanism automatically performs needle retraction without user intervention. When the device is removed from the skin, the cam follower naturally follows the cam profile, causing the needle to self-retract into the hub and self-lock, reducing the need for additional user actions.
2Manufacturing precision
If a locking mechanism is added to control penetration depth, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The cam mechanism provides depth control only at the critical moment of insertion, where precise penetration depth is needed. The cam profile is designed with specific geometric features that engage the follower at predetermined positions, providing localized precision control rather than requiring complex mechanisms throughout the entire device.
Solution Approach 2:
The cam profile geometry is designed to change the positional parameters of the needle during insertion. By varying the cam surface contour, the mechanism automatically adjusts the needle's penetration depth and orientation angles, achieving precise control through geometric parameter variation rather than mechanical adjustments.
3Ease of operation
If the needle is kept extended for easy access, then ease of operation is improved, but harmful factors increase due to exposure risk
Solution Approach 1:
The needle transitions dynamically between retracted and extended states based on operational needs. During insertion, the needle is extended; during removal and disposal, it automatically retracts. This dynamic positioning reduces exposure time and risk while maintaining accessibility when needed.
Solution Approach 2:
The hub serves as an intermediary protective structure that houses the needle when not in use. The cam mechanism acts as a mediator that controls the needle's transition between protected and exposed states, ensuring the needle is only accessible during the brief moment of medical procedure.
Data Source
Figure 1
Figure 2a~2c
Figure 2d~2f
AI summary
The invention relates to an access device comprising: a base (1) for aligning the access device with the skin of a patient; a needle for puncturing the skin, the needle comprising a hub (2) and a cannula (10), and the needle being movably mounted in the base (1) such that it can move between a first, fully retracted, and a second, maximally extended, position; and a locking mechanism which engages when the needle retracts from the second position and reaches a discrete third position, inhibiting the needle from further retracting to the first position. According to the invention, the access device is actuatable to disengage the locking mechanism.