Reciprocating Linear Motion Mechanism with Overload Protection

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Solution Overview

Problem

Existing reciprocating linear motion mechanisms in medical devices lack intrinsic protection against system overload, leading to potential damage when external forces are applied, and they often have complex structures that compromise safety and reliability.

Innovation Solution

A self-braking mechanism with an overload protection system, featuring a rotatable shaft with a smooth external surface, integrated unidirectional clutches, and a belt transmission mechanism, which converts rotary motion into reciprocating motion while ensuring compactness and reliability through a platform-mounted drive unit and sliding or rolling guide shoes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional threaded screw and nut mechanism is used for reciprocating motion, then the structure is simple, but the mechanism lacks overload protection and is prone to damage under external forces

Engineering Contradiction:

Improveoverload protectionVSAvoidmechanism structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediate mechanism comprising unidirectional clutches that act as mediators between the drive unit and the transport mechanism. These clutches allow the system to absorb reverse forces without transmitting them to the drive unit, providing intrinsic overload protection while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanism automatically protects itself from overload through the self-braking feature and unidirectional clutches that engage passively when reverse forces are applied. The system does not require external sensors or control systems to detect overload conditions - the mechanical design inherently prevents damage.

Inventive Principle:

Principle #25Self-service

2Reliability

If a reciprocating linear motion mechanism is designed for medical devices, then safety and reliability are critical, but existing mechanisms lack intrinsic protection against system overload

Engineering Contradiction:

ImprovesafetyVSAvoiddamage from external forces

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements beforehand cushioning by designing the mechanism to automatically absorb and dissipate reverse forces before they can cause damage. The unidirectional clutches and self-braking feature create a protective buffer that engages immediately when overload conditions occur, preventing harmful effects to the drive unit and other components.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If the drive unit is mounted on the platform, then the mechanism achieves compact structure and reliable operation, but the complexity of integrating the drive unit increases

Engineering Contradiction:

Improvecompact structureVSAvoidintegration complexity

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The patent merges the drive unit with the platform, making them an integrated assembly that moves together during reciprocating motion. This combination eliminates the need for separate mounting structures and simplifies the overall design, achieving compactness while the modular nature of the integration keeps manufacturing feasible.

Inventive Principle:

Principle #5Merging (Combining)

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 mechanism effectively prevents damage from overloads, ensuring safe and reliable operation by allowing continuous rotary motion conversion to linear motion with simultaneous movement of the drive unit, maintaining a compact structure and enhancing safety features.

Implementation Method 1

The intermediate mechanism comprises at least two unidirectional clutches oppositely oriented on the smooth, rotatable shaft

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

each unidirectional clutch comprises rolling elements each of which is mounted on a respective recess with a wedge-shaped edge made in the body of the clutch or directly in the intermediate mechanism and is supported by a spring element

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

rolling elements so arranged that points of contact of said rolling elements with the smooth surface of the shaft determine a helix

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP2949967B1Mechanism for reciprocating linear motion for a medical device

Publication Date: 2020.05.06 FUNDACJA ROZWOJU KARDIOCHIRURGII IM PROF ZBIGNIEWA RELIGI

Figure 1~2
Figure 3~4
Figure 5~6

AI summary

A mechanism for reciprocating linear motion of a medical device comprises a body (3), wherein are mounted a rotatable shaft (2) driven with a drive unit (5) and a guide (1) with a slidably platform (4) mounted thereon. The rotatable shaft (2) has a smooth external surface and is connected with a shaft of the drive unit (5) by means of an intermediate mechanism (6) comprising at least two unidirectional clutches (7, 8) mounted on the smooth rotatably shaft (2) in opposite directions. The platform (4) is integrated with a transport mechanism (11) which is mounted on the rotatable shaft (2) and comprises rolling elements (12) so arranged that points of contact of said rolling elements (12) with the smooth surface of the shaft (2) determine a helix.