Injection Device Trigger Retention Visual Readiness
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Solution Overview
Problem
Existing injection devices lack a simple and cost-effective method to provide visual indication of readiness for use or completion of the injection process, often relying on complex safety interlocks and mechanisms.
Innovation Solution
An injection device with a trigger mechanism that moves from a rest to an active position, allowing the syringe to extend and discharge, featuring a visual indicator that retains the trigger in its active position after use, integrated with a safety interlock mechanism for simplicity and optimal positioning during administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex safety interlock mechanism is used to prevent accidental operation, then safety is improved, but device complexity increases
Solution Approach 1:
The patent combines the safety interlock function and visual indicator function into a single integrated mechanism. The indicator member is mechanically linked to the drive spring assembly, so that the same components that control safety also provide visual feedback. This merging eliminates the need for separate safety and indication systems, reducing overall device complexity while maintaining safety functionality.
Solution Approach 2:
The indicator member serves multiple functions: it acts as part of the safety interlock mechanism preventing accidental discharge, and simultaneously provides visual indication of the drive spring state (ready/unready). By designing this single component to fulfill both safety and indication roles, the patent reduces the number of separate parts needed, thereby reducing device complexity while improving or maintaining safety.
2Loss of information
If a visual indicator mechanism is added to show readiness status, then information feedback is improved, but device complexity increases
Solution Approach 1:
The visual indicator is merged with the existing drive spring assembly and safety interlock mechanism. The indicator member is positioned to move with the drive spring, and its visual state (visible/not visible, positioned in certain locations) directly reflects the compression state of the drive spring. This integration means no separate indicator mechanism is added - the existing moving parts provide the indication function.
Solution Approach 2:
The drive spring assembly itself provides the visual indication through its own movement and positioning. As the drive spring compresses and expands, the indicator member automatically changes position or visibility state without requiring an additional actuating mechanism. The system uses its own operational movements to provide feedback, eliminating the need for separate indicator actuators.
3Ease of operation
If the trigger mechanism is simplified for easier operation, then ease of operation is improved, but safety may be compromised
Solution Approach 1:
The indicator member provides advance visual information about the drive spring state before the trigger is pulled. Users can see whether the device is ready for discharge based on the indicator position, which corresponds to the drive spring compression state. This preliminary visual feedback allows users to confirm readiness before operation, maintaining safety while simplifying the trigger mechanism itself - users don't need to understand complex internal states, just check the simple visual indicator.
Data Source
AI summary
An injection device 110 is described having a housing 112 that receives a syringe 114. The syringe 114 is biased by a return spring 126 from an extended position in which the needle 118 extends from the housing 112 through an exit aperture 128 to a retracted position in which it does not. A drive spring 130 acts via a drive to advance the syringe 114 from its retracted position to its extended position and discharge its contents through the needle 118 and a return spring 126, brought into play when the drive has reached a nominal return position, restores the syringe 114 to its retracted position. A releasable locking mechanism retains the syringe 114 in its retracted position. A sleeve 119 projects from the exit aperture 128 and can be depressed to release the locking mechanism. A trigger 300 has a rest position, in which it engages the drive, retaining it in a position corresponding to the retracted position of the syringe 114, and a depressed position, in which it no longer causes the drive to be so retained. The sleeve 119 normally locks the trigger 300 in its rest position. However, depression of the sleeve 119 into the exit aperture 128, allows the trigger to be depressed. Thereafter, the trigger 300 is retained in its active position.