Medical Device Actuator Spring Lock Mechanism

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Solution Overview

Problem

Biopsy devices with multiple actuators and springs are complex in structure and operation, making them difficult to control and use effectively.

Innovation Solution

A simplified actuator design using a single spring with a preloaded force to drive both the needle and needle tube units, featuring a housing, driving unit, and locks that allow tandem movement and sliding relative to each other under spring restoring force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two actuators and two springs are used to control needle and needle tube movement, then the biopsy device can perform tissue sampling, but the structure becomes complex and operation becomes difficult

Engineering Contradiction:
Improvebiopsy functionVSAvoidactuator structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines two separate actuators and two springs into a single integrated actuator with one spring. The first and second cars (representing needle and needle tube drive mechanisms) are both driven by the same spring force, eliminating the need for separate actuators while maintaining the ability to perform both needle insertion and needle tube advancement functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single spring serves multiple functions: it provides driving force for both the first car (needle drive) and the second car (needle tube drive). The lock mechanism allows the same spring to sequentially drive different components, making the spring a universal driving element that replaces two separate actuators.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If two actuators and two springs are used to control needle and needle tube movement, then the biopsy device can perform tissue sampling, but the operation becomes complex

Engineering Contradiction:
Improvebiopsy functionVSAvoidoperation complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent combines two separate actuators and two springs into a single integrated actuator with one spring. The first and second cars (representing needle and needle tube drive mechanisms) are both driven by the same spring force, eliminating the need for separate actuators while maintaining the ability to perform both needle insertion and needle tube advancement functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The lock mechanism dynamically switches the connection between the spring and the two cars. When the lock is in the first position, the spring drives the first car; when switched to the second position, the spring drives the second car. This dynamic reconfiguration simplifies operation by allowing a single actuator to control both functions sequentially.

Inventive Principle:
Principle #15Dynamics

3Force

If a preloading force on the spring is not easy to control, then the spring can provide driving force, but the precision of force application is poor

Engineering Contradiction:
Improvespring driving forceVSAvoidpreloading force control
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The patent replaces direct mechanical preloading adjustment with a lock-based force transmission system. The lock mechanism with protrusions and snaps provides discrete, controllable force transmission states, replacing the need for precise continuous preloading force adjustment while maintaining effective spring-driven operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The actuator is simpler in construction and easier to use, allowing for precise control of the needle and needle tube movement, enhancing the biopsy process with a single spring driving both units.

Implementation Method 1

a spring capable of storing a projecting force when being compressed, the spring being able to move the first and second cars forward together when the first and second cars are connected together

Methodology Applied
Scientific EffectElastic potential energy: Elasticity

Implementation Method 2

when the first protrusion disengages from the first snap, the spring moves the first car and the second car in tandem relative to the housing

Methodology Applied
Scientific EffectSpring restoring force: Elasticity

Implementation Method 3

when the second protrusion is disengaged from the second snap, the first car further slides relative to the second car under a restoring force of the spring

Methodology Applied
Scientific EffectSpring restoring force: Elasticity

Data Source

PatentEP3000403B1Actuator of medical device
Publication Date: 2019.10.23 JOHNSON ELECTRIC INTERNATIONAL AG
  • EP3000403B1 patent drawingFigure 1~2
  • EP3000403B1 patent drawingFigure 3~3A
  • EP3000403B1 patent drawingFigure 4~4B

AI summary

An actuator for a medical device includes a housing (10), a driving unit (20) mounted in the housing, a first moving unit (30) slidably mounted in the housing and movable by the driving unit. The first moving unit includes a movable first car (32), a spring (70) with two ends thereof abutting the housing (10) and first car (32), respectively, and a lock (40) formed between the driving unit (20) and first car (32). The lock includes a first snap (42) and a first protrusion (45) detachably engagable with the first snap (42). One of the first snap (42) and first protrusion (45) is formed on the first car (32), and the other is formed on the driving unit (20). When the first protrusion (45) disengages from the first snap (42), the spring (70) moves the first car (32) relative to the housing (10).