Cap Assembly Interlock for Tamper-Evident Injection Devices
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Solution Overview
Problem
Existing medicament delivery devices face the risk of accidental activation during transportation or handling, and there is a lack of a robust mechanism to prevent recapping and indicate tampering or exposure of the medicament delivery member's sterility.
Innovation Solution
A medicament delivery device with a removable cap assembly featuring an inner tubular integrity lock member and an outer tubular cap body, which includes a resilient structure to prevent the activation member from moving into the retracted position accidentally, and provides a tamper-proof indication by transitioning between initial and intermediate positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple cap is used to cover the medicament delivery member, then the device structure is simple and easy to manufacture, but the device cannot prevent accidental activation during transportation or handling
Solution Approach 1:
The cap assembly is divided into multiple functional segments: an outer cap body for coverage, an inner integrity lock member with resilient structure for preventing activation, and a deshielder for shield removal. Each segment performs a specific function, allowing the system to achieve reliable accidental activation prevention while maintaining reasonable structural complexity through modular design.
Solution Approach 2:
The resilient structure of the integrity lock member is pre-configured to engage with the activation member and prevent it from moving into the retracted position. This preliminary anti-action counteracts any accidental forces that might trigger activation during transportation or handling, ensuring the device remains safe until intentional use.
2Reliability
If a mechanical interlock is added to prevent accidental activation, then the reliability improves, but the ease of operation deteriorates due to additional steps required
Solution Approach 1:
The integrity lock member is pre-positioned in the assembled device with its resilient structure already engaged to prevent activation. The user does not need to manually engage or disengage any mechanisms during operation - simply removing the outer cap body automatically releases the lock through the predetermined motion path, maintaining ease of operation while ensuring safety during storage and transport.
3Ease of operation
If the cap assembly is designed to allow easy removal for shield access, then the ease of operation improves, but the ability to provide tamper-proof indication deteriorates
Solution Approach 1:
The cap assembly incorporates a dynamic transition through an intermediate position during removal. The predetermined motion path guides the outer cap body through distinct states: initially assembled position (providing tamper-proof indication), intermediate position (allowing shield access while maintaining lock engagement), and fully removed position. This dynamic design allows easy shield removal while preserving the ability to indicate tampering through the staged motion sequence.
4Reliability
If a robust integrity lock mechanism is implemented, then the prevention of recapping improves, but the device complexity increases
Solution Approach 1:
The integrity lock member is nested within the outer cap body, with the resilient structure contained inside the tubular housing. This nested configuration allows the robust lock mechanism to be integrated within the cap assembly without significantly increasing overall device complexity. The compact nested design maintains prevention of recapping while avoiding excessive structural complexity.
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 effectively prevents accidental activation and recapping, ensuring the sterility of the medicament delivery member by maintaining the shield until intentional use, providing a clear indication of tampering or exposure.
Implementation Method 1
an inner tubular integrity lock member (9) having a resilient structure configured to interact with both a first engaging structure of the activation member and a second engaging structure of the housing for preventing the activation member from moving into the retracted position
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The present disclosure relates to a medicament delivery device comprises: a housing having a proximal end and a distal end; a medicament container positioned in the housing and having a medicament delivery member shield; a medicament delivery mechanism associated with the medicament container; an activation member operably connected to the medicament delivery mechanism and longitudinally movable in relation to the housing from an extended position to a retracted position to activate the medicament delivery mechanism; and a removable cap assembly comprising a deshielder, an inner tubular integrity lock member having a resilient structure configured to interact with both a first engaging structure of the activation member and a second engaging structure of the housing for preventing the activation member from moving into the retracted position; and wherein the removable cap assembly further comprises an outer tubular cap body which is movable in relation to the housing and to the inner tubular integrity lock member from an initial position in which the outer tubular cap body is releasibly connected to the housing and is disengaged from the inner tubular integrity lock member, to an intermediate position in which the outer tubular cap body is partially disengaged from the housing for giving tamper proof indication and in which the outer tubular cap body is fixedly engaged to the inner tubular integrity lock member for allowing the removal of the medicament delivery member shield.