Actuator Case Structure for Compact Multi-Syringe Injection Devices
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Solution Overview
Problem
Existing injection devices face challenges in reducing size and weight due to the need for additional frames to support the weight of heavier upper covers, particularly when multiple syringes are used, leading to increased device dimensions and weight.
Innovation Solution
The injection device incorporates a case that houses a drive mechanism, including a feed screw shaft and a sliding member with detents, where the detents are guided by a groove in the case, allowing for reduced size and weight by eliminating the need for external frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a frame is provided to support the weight of the upper cover, then the weight support capability is improved, but the housing space is narrowed and the device size increases
Solution Approach 1:
The patent merges the frame structure with the actuator case by integrating the support function into the existing case component. The case is designed to directly support the upper cover weight without requiring a separate frame structure, thereby combining multiple functions into a single component and avoiding space consumption.
Solution Approach 2:
The patent extracts the frame structure from the overall device design and replaces it with the actuator case itself. By making the case the primary load-bearing component, the unnecessary frame is removed, freeing up housing space while maintaining weight support capability.
2Adaptability or versatility
If the upper cover weight increases to accommodate multiple syringes, then the syringe mounting capacity is improved, but the device weight and size increase
Solution Approach 1:
The patent replaces the traditional mechanical support system (frame + heavy covers) with a more efficient actuator-based system. The actuator case serves as the structural backbone, and the detent-groove mechanism provides mechanical advantage for weight support without adding overall device weight.
Solution Approach 2:
The patent introduces dynamic elements through the detent-groove mechanism that allows for adjustable and adaptable mounting configurations. This dynamic system enables the device to accommodate varying weights and configurations without requiring a permanently heavy structure.
3Manufacturing precision
If the detent is fixed in the groove portion, then the positioning precision is improved, but the detent cannot adapt to radial movements and reliability decreases
Solution Approach 1:
The patent makes the detent dynamic by allowing it to move radially within the groove portion while maintaining engagement. This dynamic capability enables the detent to adapt to radial movements of the feed screw shaft during operation, maintaining both positioning precision and operational reliability.
Solution Approach 2:
The patent segments the detent's movement capabilities into different degrees of freedom: axial movement is constrained for positioning precision, while radial movement is permitted for adaptability. This segmentation of constraints allows the detent to satisfy multiple functional requirements simultaneously.
Data Source
AI summary
An injection device includes a syringe holder on which a syringe filled with a liquid medicine is mounted, a presser that pushes out the liquid medicine from the mounted syringe, and an actuator having a case that houses a drive mechanism moving the presser forward or backward. The injection device also includes a first cover and a second cover that house the actuator, wherein at least one of the first cover or the second cover is fixed to the case.