Spring-Propelled Infusion Pump for Tamper-Resistant Medicament Delivery

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Solution Overview

Problem

Existing ambulatory infusion pumps are bulky, inconvenient, and lack safety features in case of breakage or incorrect use, with fluid flow regulation dependent on variable spring force and lacking mechanisms to prevent unauthorized access or tampering.

Innovation Solution

An infusion pump design featuring a propulsion device with concentrically arranged helical springs, a drive system with a retaining member and rigid member to control fluid flow, and safety mechanisms to prevent unauthorized access, including a pinch valve and locking features to ensure secure and controlled medicament delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mains electricity or portable electrical cells are used to power the infusion pump, then the pump can provide controlled fluid delivery, but the pump becomes physically large and heavy making portability inconvenient

Engineering Contradiction:
Improvecontrolled fluid deliveryVSAvoidpump weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the electrical power system with a mechanical spring-based propulsion device. The spring stores potential energy and provides the force needed to propel the piston, eliminating the need for heavy batteries or electrical connections while maintaining controlled fluid delivery capability.

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

Solution Approach 2:

The infusion pump uses periodic release of the spring mechanism to deliver fluid in controlled intervals. The spring is gradually released through a controlled mechanism that allows periodic fluid delivery at regulated rates, maintaining therapeutic effectiveness without continuous power supply.

Inventive Principle:
Principle #19Periodic action

2Volume of moving object

If a spring provides force to deliver fluid from the receptacle, then the pump size can be reduced, but the spring force is variable and cannot regulate fluid flow accurately

Engineering Contradiction:
Improvepump sizeVSAvoidfluid flow regulation
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent transforms the static spring force into a dynamic controlled system. A controlled release mechanism gradually releases the spring tension, converting the variable spring force into a regulated, controllable fluid delivery system. This allows accurate flow regulation while maintaining compact pump size.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates a controlled release mechanism that responds to the spring's tension changes and regulates fluid delivery accordingly. As the spring force varies during extension, the control mechanism adjusts the release rate to maintain consistent fluid flow, achieving precise regulation despite the variable input force.

Inventive Principle:
Principle #23Feedback

3Productivity

If the spring is released to deliver fluid, then fluid flow is achieved, but there are no safety features to prevent unauthorized access or tampering

Engineering Contradiction:
Improvefluid deliveryVSAvoidsafety against tampering
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent incorporates a safety cap that must be removed before the pump can operate. This preliminary action prevents unauthorized access to the fluid receptacle and ensures that only authorized users can initiate fluid delivery. The cap may include additional safety features like breakable seals or coded removal mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The safety cap and locking mechanisms are designed to prevent accidental activation or tampering before use. The system includes built-in safety features that must be deliberately activated by authorized personnel, providing a layer of protection against unauthorized access or misuse before fluid delivery begins.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Force

If a cable is used to retain the spring, then the spring can be held in place, but the cable cannot be controlled during fluid delivery to regulate flow and provides no safety if the cable breaks

Engineering Contradiction:
Improvespring retentionVSAvoidflow control and safety
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent replaces the simple cable retention system with a controlled mechanical release mechanism. This mechanism provides both secure retention of the spring and controlled release capability, allowing regulation of fluid flow while maintaining safety through a more reliable mechanical system that can detect and respond to cable failure.

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

Solution Approach 2:

The controlled release mechanism acts as an intermediary between the spring and the fluid delivery system. It translates the spring's mechanical force into regulated fluid flow while providing safety functions, including detection of cable or mechanism failure that would prevent unauthorized or uncontrolled fluid delivery.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design provides a compact, secure, and reliable infusion pump that ensures accurate medicament delivery, prevents unauthorized access, and includes safety features to prevent fluid leakage or tampering, enhancing user convenience and safety.

Implementation Method 1

The propulsion device is compressed when the fluid receptacle is provided in the infusion pump body such that the propulsion device is biased to advance a piston along an interior of the fluid receptacle to propel fluid from the fluid receptacle

Methodology Applied
Scientific EffectElastic potential energy: Spring

Data Source

PatentEP3927392B1Infusion pump
Publication Date: 2026.04.01 DANBY MEDICAL LTD
  • EP3927392B1 patent drawingFigure 1~2
  • EP3927392B1 patent drawingFigure 3~4
  • EP3927392B1 patent drawingFigure 5~6

AI summary

An infusion pump for administering controlled doses of fluid comprises a pump body 2 and cap 3 attachable to the pump body 2 to retain a medicament fluid receptacle 4 in the pump body 2, The fluid receptacle 4 is connected to a tube 12 for dispensing the fluid. The tube 12 is directed through a normally closed valve within the cap 3. The pump body 2 comprises a propulsion device engaging with a piston support 6 of the fluid receptacle 4, coupled to a retaining member, a drive system coupled to the retaining member and a rigid member coupled to the drive system. Actuation of the drive system enables the propulsion device to deliver fluid. In addition, the rigid member moveably projects into the cap to open the normally closed valve to allow the passage of fluid.