Needle insertion device with decoupled spring mechanism
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Solution Overview
Problem
Existing hand-held devices for intravenous catheterization lack precision and comfort due to vibrations caused by spring activation and inability to guide needle insertion, and require more operator skill, especially when dealing with difficult patients.
Innovation Solution
A hand-held device with decoupling means between the needle and casing, allowing controlled needle movement and detection of target position using sensors, which decouples the needle from the casing once the target is reached, preventing further movement and ensuring precise placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring is used to retract the needle after catheterization, then the needle is automatically retracted to improve safety, but vibrations are induced causing operator discomfort
Solution Approach 1:
The harmful vibrations are isolated from the operator by extracting the spring mechanism into a separate, enclosed space (the barrel). The operator holds only the handle, which is decoupled from the vibrating barrel containing the spring, thus removing the source of discomfort while preserving the safety function.
Solution Approach 2:
The device is segmented into distinct functional modules: the handle for operator control, the barrel containing the spring mechanism, and the needle assembly. This segmentation allows the vibrating components to be isolated from the operator's hand, reducing discomfort while maintaining the retraction safety feature.
2Manufacturing precision
If manual catheterization is performed without guidance, then the device is simpler to manufacture, but precision of needle placement in non-homogeneous material is reduced
Solution Approach 1:
The device incorporates a guide structure that constrains the needle's movement from simple linear insertion to a controlled path through non-homogeneous material. The guide provides dimensional constraints that enable precise needle placement while maintaining relative simplicity in the overall device design.
3Measurement precision
If the needle is rigidly coupled to the casing, then the structure is simpler, but the needle cannot be precisely positioned or retracted independently of the casing
Solution Approach 1:
The coupling between the needle and casing is made dynamic rather than rigid. The spring-loaded mechanism allows the needle to move independently relative to the casing during insertion and retraction, enabling precise position control while using a relatively simple mechanical coupling structure.
Data Source
Figure 1~2b
Figure 3~5
Figure 4a~4b
AI summary
A hand-held device (10) for precisely positioning a tip (18) of a needle (16) into a blood vessel (V), at a desired target position, it comprises: a casing (12) adapted to be hand-held by an operator; a shaft (14) extending along a longitudinal axis (x) and carrying at a distal end thereof the needle (16), the shaft (14) being mounted in the casing (12); decoupling or actuating means (22, 22') respectively operable to decouple the shaft (14) from the casing (12); detection means (26) arranged to provide signals indicative of at least one physical characteristic of the vessel into which the needle tip (18) has to be inserted; and control means (24) operatively connected with the decoupling or actuating means (22, 22') and to the detection means (26) and configured to determine, based on the signals received from the detection means (26), whether the needle tip (18) has reached said target position and to operate the decoupling or actuating means (22, 22') to decouple the shaft (14), and hence the needle (16), from the casing (12) or to actively move the shaft (14) relative to the casing (12), respectively.