Cam-Actuated Clamp Safety Mechanism for Infusion Pumps

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Solution Overview

Problem

Existing infusion pump systems risk uncontrolled flow of infusion liquid when the pump door is closed, especially if the tube is not correctly positioned or if there are faults in the pump, leading to potential safety hazards.

Innovation Solution

A safety device that ensures the clamp is closed when the door is opened and remains closed when the door is closed, using a cam mechanism integrated with the door handle to control the clamp's position independently of the pump's power state or tube positioning, with a mechanical fuse to prevent unintended opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the clamp is opened when the door closes, then the pump can operate, but uncontrolled flow of infusion liquid may occur causing safety hazards

Engineering Contradiction:
Improvepump operationVSAvoiduncontrolled flow of infusion liquid
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary checks before allowing pump operation. The control unit verifies that the clamp is in the open position and the tube is correctly positioned in the pump before enabling operation after door closing, preventing uncontrolled flow from occurring

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the positions of the clamp and tube through sensors and provides feedback to the control unit. This feedback mechanism ensures that the pump only operates when safe conditions are confirmed, and can automatically stop operation if unsafe conditions develop

Inventive Principle:
Principle #23Feedback

2Ease of operation

If electrical means are used to close the clamp, then the clamp can be controlled, but the system fails if power supply issues occur

Engineering Contradiction:
Improveclamp controlVSAvoidsystem failure under power issues
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The clamp is designed with a spring-loaded mechanism that automatically returns to the closed position when electrical power is lost. The spring force ensures the clamp maintains its safe closed state without requiring continuous electrical power, making the system self-protecting during power failures

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The clamp mechanism uses asymmetric force application with a strong spring bias toward the closed position. Electrical actuation is only needed to overcome this spring force and open the clamp, while closing is automatically maintained by the spring, creating inherent fail-safe behavior

Inventive Principle:
Principle #4Asymmetry

3Object-affected harmful factors

If the clamp is closed when the door opens, then safety is improved, but the clamp may close prematurely causing operational delays

Engineering Contradiction:
Improveuncontrolled flow preventionVSAvoidoperational delays
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The clamp closes automatically when the door opens, performing the safety action in advance before the user interacts with the pump. This preliminary closing ensures safety is established first, then the system waits for proper tube insertion and user confirmation before allowing operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts its state based on operational context. The clamp closes automatically on door opening, but the pump operation is dynamically enabled only when the control unit confirms safe conditions (tube positioned, clamp open), preventing premature operation while maintaining safety

Inventive Principle:
Principle #15Dynamics

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

Prevents uncontrolled infusion fluid flow by ensuring the clamp remains closed even when the door is opened, maintaining safety and integrity regardless of the pump's state or tube positioning, and operates independently of power supply issues.

Implementation Method 1

a cam (44) which, when the door (4) is closed, causes the movable part (22) to pivot in the closed position

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP2089082B2Device for controlling the opening and closing of a clamp in a positive displacement pump
Publication Date: 2023.02.22 FRESENIUS VIAL
  • EP2089082B2 patent drawingFigure 1~2
  • EP2089082B2 patent drawingFigure 3~4
  • EP2089082B2 patent drawingFigure 5~6

AI summary

The invention relates to a device for controlling the opening and closing of a clamp (2) intended to seal a flexible tube (1), for example in a positive displacement pump, including: a casing (3) that can be closed with a door (4); a tube (1) placed inside the casing (3); a clamp (2) also placed in the casing (3), which cooperates with the tube (1) in order to open or seal same; and means (44) for closing the clamp (2) when the door (4) is being opened. The device also includes means (44) for closing the clamp (2) when the door (4) is being closed. As well as ensuring that the tube (1) is always closed when the door is being opened, the inventive safety device also ensures that the tube (1) remains closed once the door has been closed as long as a suitable device (31) does not trigger the opening of the clamp (2). The fully mechanical closure device is not exposed to the dangers of a faulty power supply.