Passive Integrated Needle Safety Device for Injection Systems
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Solution Overview
Problem
Existing passive needle safety devices for injection devices, such as syringes, face issues like the need for a removable needle plug, pop-off phenomena during sterilization, and loss of spring effect over time, leading to unreliable protection against accidental needle sticks and increased user discomfort during insertion.
Innovation Solution
A passive integrated needle safety device with an inner needle shield acting as both a sealing component and a spring mechanism, where the outer needle shield is movable relative to the sleeve, locking into a safety position after injection, eliminating the need for a removable plug and ensuring automatic needle protection without user activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft rubber cover is used to prevent needle leakage, then drug leakage is prevented, but the cover must be removed and discarded before injection, increasing device complexity and user steps
Solution Approach 1:
The patent combines the sealing function and the protective shield function into a single integrated structure. The distal portion of the inner needle shield serves both as the sealing element that prevents drug leakage and as part of the protective shield that covers the needle, eliminating the need for a separate removable cover
Solution Approach 2:
The inner needle shield's distal portion performs multiple functions: it seals around the needle to prevent leakage, it can be pierced by the needle to allow injection, and it forms part of the protective shielding structure. This multi-functionality eliminates the need for separate components
2Reliability
If the proximal part of the sleeve is deformed radially outwardly to achieve spring effect, then the sleeve can protect the needle after injection, but the device becomes radially cumbersome and deformation is visible which may worry users
Solution Approach 1:
The patent transitions the energy storage mechanism from radial deformation to axial compression. The energy storage portion compresses along the longitudinal axis of the device rather than deforming radially outward, maintaining a compact radial profile while still storing the necessary energy to return the shield to protective position
Solution Approach 2:
The energy storage portion is made of an elastomeric material that can be compressed axially and then elastically recover. This flexible material allows the shield to be compact during injection while automatically returning to cover the needle after injection without visible radial deformation
3Reliability
If the needle must be inserted a long distance to achieve effective spring deformation, then the sleeve can store enough energy, but this causes user stress and harm during insertion
Solution Approach 1:
The patent changes the parameters of the energy storage mechanism by using an elastomeric material with appropriate durometer hardness and designing the energy storage portion with optimized geometry. This allows sufficient energy to be stored with minimal axial compression, reducing the insertion distance required while maintaining reliable needle protection
4Ease of manufacture
If a plastic material is used for the sleeve, then manufacturing is simplified, but the material loses resilient deformation ability over time, reducing reliability
Solution Approach 1:
The patent uses an elastomeric material for the energy storage portion which combines the benefits of ease of manufacture with superior elastic memory. The elastomeric material can be molded like plastic but retains its resilient properties over time, preventing the loss of spring effect that occurs with plastic materials
5Ease of operation
If the inner needle shield is made of elastomeric material, then it can be pierced easily by the needle, but the material may deform visibly which could concern users
Solution Approach 1:
The patent divides the inner needle shield into distinct portions: a distal portion made of elastomeric material that is pierced by the needle, and a proximal portion that forms the visible protective shield. The elastomeric distal portion deforms locally at the needle puncture site while the overall shield structure maintains its shape and provides consistent visual appearance
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 solution provides a compact, easy-to-manufacture safety device that prevents accidental needle sticks by automatically covering the needle post-injection, maintaining sterility, and avoiding pop-off effects during sterilization, while reducing user discomfort and the risk of coring during needle insertion.
Implementation Method 1
an energy storage portion configured to accumulate energy as the passive safety device passes from the pre-use position to the injection position and to release energy as the passive safety device passes from the injection position to a safety position
Implementation Method 2
the inner needle shield is configured to move the outer needle shield distally as the energy storage portion releases its stored energy
Data Source
Figure 1A~1C
Figure 2~3D
AI summary
This passive safety device (1) comprises an inner needle shield (4) having a proximal end (40) configured to be sealed to a tip (102) of an injection device (100), a distal portion (42) configured to be pricked by a needle (108) in a pre-use position and pierced by the needle (108) in an injection position, and an energy storage portion (44) configured to accumulate energy as the passive safety device (1) passes from the pre- use position to the injection position and release renergy as the passive safety device (1) passes from the injection position to a safety position. The passive safety device (1) further comprises a sleeve (2) surrounding the proximal end (40), an outer needle shield (6) having a proximal end (62) slidably attached to the sleeve (2) so that the outer needle shield (6) is movable relative to the sleeve (2), and locking means configured to lock the outer needle shield (6) in the safety position. The inner needle shield (4) is configured to move the outer needle shield (6) distally as the energy storage portion (44) releases its stored energy.