Auto-injector Ramp Beam Deflection Mechanism

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Solution Overview

Problem

Existing detent mechanisms in medicament delivery devices, such as auto-injectors, face challenges in ensuring precise needle penetration depth and efficient medicament delivery while preventing component failure and ensuring safety, requiring an improved mechanism for controlled relative motion between components.

Innovation Solution

The auto-injector incorporates a syringe carrier with a ramp member and a resilient beam, where the beam head is deflected radially and tangentially by ramps to facilitate controlled movement, allowing for precise needle insertion and retraction with reduced force requirements, and ensuring the syringe carrier's controlled translation relative to the chassis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional detent mechanism is used to control axial movement of the syringe, then needle penetration depth can be controlled, but the mechanism complexity increases and reliability decreases due to component failure risks

Engineering Contradiction:
Improveneedle penetration depth controlVSAvoidcomponent failure prevention
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent employs a flexible membrane with predetermined break points instead of rigid mechanical detent components. The membrane flexes to allow controlled axial movement of the syringe for needle penetration depth control, and the predetermined break points provide reliable failure points that prevent component failure under excessive force, thereby resolving the contradiction between precision control and reliability.

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If a detent mechanism with multiple components is implemented to ensure safety and control movement, then safety is improved, but the device complexity increases

Engineering Contradiction:
Improvesafety assuranceVSAvoidmechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions (movement control, safety mechanism, and failure prevention) into a single integrated flexible membrane structure. The membrane simultaneously provides the detent action for controlled movement, the safety function through its rupture characteristics, and the failure prevention through predetermined break points, thereby reducing device complexity while maintaining safety.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The flexible membrane serves multiple functions: it acts as a detent mechanism for controlling syringe axial movement, provides safety through its rupture characteristics, and prevents component failure via predetermined break points. This multi-functionality reduces the number of separate components needed, thereby reducing overall device complexity while ensuring safety.

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

3Ease of operation

If a resilient beam with dual ramp deflection is used to control carrier movement, then ease of operation is improved with reduced force, but the mechanism complexity increases

Engineering Contradiction:
Improveuser force requirementVSAvoidramp mechanism structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent uses curved ramp surfaces on the resilient beam that guide the beam head through controlled radial and tangential deflections. The curved geometry of the ramps converts user input force into efficient motion sequences, reducing the force required to operate the mechanism while the integration of both ramps into a single beam structure minimizes overall complexity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This solution enables precise and safe medicament delivery by providing a controlled mechanism for needle insertion and retraction, ensuring consistent penetration depth and efficient delivery with reduced user force, while preventing component failure and ensuring safety.

Implementation Method 1

a resilient beam having a beam head adapted to engage the ramp member. The first ramp is adapted to deflect the beam head in a radial direction relative to the chassis and the second ramp is adapted to deflect the beam head in a tangential direction relative to the chassis

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2846855B1Auto-injector
Publication Date: 2022.03.02 SANOFI SA(FR)
  • EP2846855B1 patent drawingFigure 1A~1B
  • EP2846855B1 patent drawingFigure 2A~2B
  • EP2846855B1 patent drawingFigure 3A~3B

AI summary

Described is an an auto-injector (1) comprising a syringe carrier (7) adapted to contain a syringe (3). The syringe carrier (7) has a ramp member (7.1) with a first ramp (7.2) and a second ramp (7.3). The auto-injector (1) comprises a chassis (2) including a resilient beam having a beam head (2.1) adapted to engage the ramp member (7.1). The first ramp (7.2) is adapted to deflect the beam head (2.1) in a radial direction relative to the chassis (2) and the second ramp (7.3) is adapted to deflect the beam head (2.1) in a tangential direction relative to the chassis (2).