Anesthetic Compound Needle Linear Locking Mechanism

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Solution Overview

Problem

Existing anesthetic compound needles require complex operations to switch between locked and unlocked states, leading to potential nerve tissue damage and failure of spinal anesthesia due to the need for inner needle rotation and difficulty in sensing dura mater insertion.

Innovation Solution

A compound needle design featuring a tubular adaptor with grooves and a restricting plate that allows switching between locked and unlocked states by a simple pushing motion, eliminating the need for inner needle rotation and enhancing the sensing of dura mater insertion without risking nerve damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inner needle is rotated to switch between locked and unlocked states, then the inner needle can be fixed relative to the outer needle, but the operation becomes very complex and the moment of dura mater insertion cannot be sensed

Engineering Contradiction:

Improvefixing reliability of inner needleVSAvoidoperation complexity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the rotational mechanical engagement system with a linear pushing system. The restricting plate moves linearly along the pushing direction to engage or disengage from the protrusion, eliminating the need for rotational movement. This substitution simplifies the operation while maintaining the locking function, and allows clear sensing of dura mater insertion through resistance feedback during linear advancement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the inner needle is rotated to switch states, then locking can be achieved, but there is a possibility of damaging nerve tissue due to advancement or retraction during rotation

Engineering Contradiction:

Improvelocking functionVSAvoidnerve tissue damage risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent eliminates rotational movement by using linear pushing motion of the restricting plate. The protrusion engages with grooves on the outer needle surface through linear displacement rather than rotation, preventing unintended advancement or retraction of the inner needle that could occur during rotational operations. This reduces the risk of nerve tissue damage while maintaining effective locking.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a threadable engagement mechanism is used to fix the inner needle, then the inner needle can be locked, but the operation becomes complex and insertion sensing is lost

Engineering Contradiction:

Improveinner needle fixationVSAvoidengagement mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the threadable engagement mechanism with a simpler linear engagement system. The restricting plate with protrusion engages directly with grooves on the outer needle through linear pushing motion, eliminating threads and rotational components. This reduction in mechanical complexity makes the device easier to operate and allows clear sensing of dura mater insertion through resistance feedback.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If the inner needle is advanced or retracted during confirming or injecting operations, then the distal end may move out of the dura mater causing failure, but fixing the needle requires complex mechanisms

Engineering Contradiction:

Improveanesthesia success rateVSAvoidoperation simplicity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent uses linear pushing motion of the restricting plate to achieve locking, which is simpler than rotational mechanisms. The engaging protrusion and grooves provide reliable fixation that prevents unintended movement during anesthesia operations, while the simple linear operation maintains ease of use and allows clear sensing of insertion points.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8728036B2Anesthetic compound needle

Publication Date: 2014.05.20 UNISYS CORP

AI summary

A front portion of a tubular inner needle proximal end portion disposed at a proximal end of the inner needle is attached to a rear end portion of a tubular adaptor, a tubular outer needle proximal end portion disposed at a proximal end of the outer needle is inserted from a distal end of the adaptor, and a distal end of the inner needle is caused to protrude from a distal end of the outer needle. A restricting plate having an insertion hole through which the outer needle proximal end portion is inserted is inserted into the adaptor from an opening formed in an upper surface of the adaptor. A protrusion formed on a lower surface of the insertion hole protrudes upward and engages with one of the grooves of the outer needle proximal end portion. When the restricting plate is pushed down, the groove of the outer needle proximal end portion and the protrusion of the restricting plate are disengaged from each other and the inner needle is set to the unlocked state in which the inner needle is able to be advanced or retracted relative to the outer needle.