Syringe Guard with Spring Bias and Detents
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Solution Overview
Problem
Existing syringe safety devices often require manual activation or lack permanent locking mechanisms, risking accidental needle exposure and reuse, and may not automatically cover the needle after use.
Innovation Solution
A syringe design with a one-piece plastic construction integrating a guard that automatically covers the needle using a spring bias and cooperating detents, allowing the guard to slide from an exposed to a covered position upon plunger depression, ensuring the needle is securely protected after use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a manual shield extension mechanism is used to cover the needle, then the device structure is simple, but the device requires manual activation and may not reliably prevent accidental needle exposure
Solution Approach 1:
The guard mechanism automatically activates through plunger depression without requiring separate manual activation. The spring element stores energy during injection and automatically drives the guard to cover the needle when released, making the system self-activating and eliminating the need for user intervention to trigger protection.
Solution Approach 2:
The spring element is integrated into the guard mechanism rather than being a separate activation system. The spring is positioned within the guard structure itself, allowing automatic operation while maintaining relatively simple overall device architecture.
2Reliability
If a spring-loaded automatic guard mechanism is used, then the needle is automatically covered, but the device may lack permanent locking mechanisms allowing accidental needle exposure and reuse
Solution Approach 1:
Cooperating detents are pre-positioned on both the guard and syringe body to create permanent locking positions. The first detent locks the guard in the needle-exposed position during injection, and the second detent automatically engages to lock the guard in the needle-covered position after injection, preventing accidental exposure or reuse.
Solution Approach 2:
The plunger itself activates the release mechanism by engaging the latch member during normal injection operation. No separate activation step is needed - the injection action automatically triggers the guard to transition from exposed to covered position and lock in place.
3Reliability
If the guard is designed to slide freely on the syringe, then the device structure is simple, but the guard cannot maintain stable positions for needle exposure or coverage
Solution Approach 1:
Cooperating detents are pre-positioned on both the guard and syringe body to create permanent locking positions. The first detent locks the guard in the needle-exposed position during injection, and the second detent automatically engages to lock the guard in the needle-covered position after injection, preventing accidental exposure or reuse.
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 passive, automatic, and secure mechanism to prevent needle reuse and exposure, enhancing safety by ensuring the needle is always covered after use, reducing the risk of accidental sticks and facilitating safe disposal.
Implementation Method 1
The guard is biased from a first or retracted position wherein the needle of the syringe is exposed toward a second position wherein the guard covers the needle
Data Source
Figure 1
Figure 2
Figure 3a~3e
AI summary
The present invention provides an injection device including a syringe (12) having a distal end for receiving a needle, and a plunger inserted into the proximal end. A guard (14) is slidable on the syringe, has a proximal end, a distal end, and is biased from a first position wherein the needle is exposed toward a second position wherein the guard covers the needle. The syringe includes a body having a central cylindrical opening for receiving medicine and the plunger, and further includes a pair of longitudinally extending members (18) on opposite sides of the body. The guard has an interior configuration for mating with the longitudinal members and sliding thereon.